CA2229801A1 - Thermoplastic lens blocking material - Google Patents

Thermoplastic lens blocking material Download PDF

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Publication number
CA2229801A1
CA2229801A1 CA002229801A CA2229801A CA2229801A1 CA 2229801 A1 CA2229801 A1 CA 2229801A1 CA 002229801 A CA002229801 A CA 002229801A CA 2229801 A CA2229801 A CA 2229801A CA 2229801 A1 CA2229801 A1 CA 2229801A1
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CA
Canada
Prior art keywords
lens
composition
blocking
blocking composition
block
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
CA002229801A
Other languages
French (fr)
Inventor
William L. Parish, Jr.
Joel D. Oxman
Michael Govek
F. Andrew Ubel
Patrick D. Hyde
John H. Ko
Richard L. Severance
Todd R. Williams
Philip G. Martin
Sharon R. Benjamin
Carole Sedlock
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
3M Co
Original Assignee
Individual
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Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of CA2229801A1 publication Critical patent/CA2229801A1/en
Abandoned legal-status Critical Current

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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B24GRINDING; POLISHING
    • B24BMACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B13/00Machines or devices designed for grinding or polishing optical surfaces on lenses or surfaces of similar shape on other work; Accessories therefor
    • B24B13/005Blocking means, chucks or the like; Alignment devices
    • B24B13/0057Deblocking of lenses
    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09JADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00Adhesives in the form of films or foils
    • C09J7/20Adhesives in the form of films or foils characterised by their carriers
    • C09J7/22Plastics; Metallised plastics
    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09JADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00Adhesives in the form of films or foils
    • C09J7/30Adhesives in the form of films or foils characterised by the adhesive composition
    • C09J7/38Pressure-sensitive adhesives [PSA]
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08LCOMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L33/00Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
    • C08L33/04Homopolymers or copolymers of esters
    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09JADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2301/00Additional features of adhesives in the form of films or foils
    • C09J2301/10Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet
    • C09J2301/12Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet by the arrangement of layers
    • C09J2301/124Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet by the arrangement of layers the adhesive layer being present on both sides of the carrier, e.g. double-sided adhesive tape
    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09JADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2301/00Additional features of adhesives in the form of films or foils
    • C09J2301/30Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier
    • C09J2301/302Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier the adhesive being pressure-sensitive, i.e. tacky at temperatures inferior to 30°C
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00Stock material or miscellaneous articles
    • Y10T428/28Web or sheet containing structurally defined element or component and having an adhesive outermost layer
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00Stock material or miscellaneous articles
    • Y10T428/28Web or sheet containing structurally defined element or component and having an adhesive outermost layer
    • Y10T428/2848Three or more layers
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00Stock material or miscellaneous articles
    • Y10T428/28Web or sheet containing structurally defined element or component and having an adhesive outermost layer
    • Y10T428/2852Adhesive compositions
    • Y10T428/2878Adhesive compositions including addition polymer from unsaturated monomer
    • Y10T428/2891Adhesive compositions including addition polymer from unsaturated monomer including addition polymer from alpha-beta unsaturated carboxylic acid [e.g., acrylic acid, methacrylic acid, etc.] Or derivative thereof

Abstract

The present invention provides thermoplastic ophthalmic lens blocking compositions that have many advantages over traditional metal alloy materials.
Preferred compositions comprise a homopolymer or copolymer of epsilon-caprolactone, have a number average molecular weight between 3,000 and 100,000, and a polydispersity less than 10. The composition may also comprise one or more modifiers, fillers or heat absorbing materials. In one embodiment, the composition is used to fill the cavity between a preformed lens block and a lens. In another embodiment the composition is used to form a lens block.
Methods of holding a lens blank are taught. Tapes that provide a receptive surface against which the composition may be adhered are disclosed.

Description

- W O 97/10924 PCT~US96/14668 Thermoplastic Lens Blocking Material Field The present invention relates generally to a thermoplastic blocking composition for use in forming or attaching a lens block to an ophth~lmic lens blank or a lens blank coating or tape and to preformed base blocks and lens blank tapes used with the blocking composition. The present invention also relates generally to methods of forming or attaching a lens block to an ophth~lmic lens blank thereby facilit~ling the use of conventional machining, grinding and processing equipment to generate the ophth~lmic lens.

Background A number of dirr~ l methods have been used to hold a lens in place during the surfacing process. The method most commonly used at present makes use of a low-melting-temperature metal alloy to form or attach a "block"
to the semifini~h~rl surface of a lens "blank." This procedure is often referred to as "lens blocking."
2 o A common low-melting-temperature alloy comprises bismuth, tin, lead, ~lmillm, indium, and antimony. When these elements are combined correctly, the alloy melts at a temperature considerably lower than any one of its component elements would melt by itself. The alloy will neither cause a plastic lens to melt nor a glass lens to crack. For example, one alloy that melts at 47 ~C is made from the following combination of metals: 45% bismuth; 23% lead;
8% tin; 5% c~tlmillm; and 19% indium. This alloy will work for either plastic or glass lenses. In general, a higher melting alloy (e.g, one which melts at 70~C) will generally only work for glass lenses.

ullfolLullaLely~ many of the present metal alloy materials pose signific~nt ~llvilol~ ental and health hazards. For example, lead, a common ingredient in many alloys, is considered to be a strong protoplasmic poison which can be introduced into the body through ingestion, inh~l~tion and skin absorption.
Similarly, c~lmillm may also pose signifi~nt health hazards. These hazards are particularly acute since many of the procedures used in the ophth~lmic laboratory may cause fumes and/or dust particles of these metals to be released to the air, thereby creating ellvho~ ental and health hazards for those formlll~fing these alloys or those working with them.
0 A "blocker" is a piece of equipment employed for the purpose of lens blocking. Blockers that use metal alloy either inject molten alloy between the s.-mifini~h~d lens and a preformed block, or mold a block fully and completely from the alloy material. Both types of blockers have a melting pot that is thermostatically regulated, and a heated feeding tube.
Ideally, for plastic lenses, the alloy temperature is kept just above its melting point until it fills in the cavity between the lens and lens block. For example, the 47 ~C alloy used for plastic, polycarbonate and polyurethane lenses should preferably be kept at 52 ~C, or even lower if possible. For glass lenses the alloy temperature may be m~int~inl~fl at higher temperatures (e.g., 2 0 about 77 ~C).
Once on the lens, the alloy should be cooled as rapidly as possible. In addition to saving time, rapid cooling of the alloy helps prevent the formation of aberrations or indentations on the surface of the lens. However, it is also important that the alloy be allowed to cool fully before generating the lens. If a 2 5 lens is generated too soon after blocking, the alloy may not have cooled evenly, thereby producing surface distortion or waviness or the lens may become dislodged from the blank.
There are two convenient ways used to harden the alloy quickly. The first is to circulate cold running water or a coolant through a water or "chill"

ring, which fits around the lens block. This causes the lens block and alloy to chill, "freezing" the alloy. The second method is to chill the block (e.g., in arefrigerator) before it is placed on the blocker.
A tape or other lens coating is often used when surfacing lenses: (1) to L~lev~lll the lenses from being scratched; (2) to serve as a heat shield (e.g., to protect a plastic lens from warpage caused by the heat of the alloy); (3) to achieve better or enh~need alloy adherence; and (4) to elimin~te the step of cleaning the lens after surfacing. The cleanest and most common method for protecting lens surfaces and holding the block securely is the use of a surface tape. Tapes for this purpose were developed by the 3M Company and may be applied by placing the lens in a small chamber, stretching the tape over the chamber, and applying a partial vacuum. The lens moves up to the tape and the tape is pulled down over the lens surface. Alternatively, lens coatings, available in brush-on and spray applications, may be applied to the convex side of the lens.
Blocks used for glass lenses ("glass blocks" or "glass-lens blocks") are generally about 43 mm in tli~m~ter They do not need to be large, since their purpose is purely to hold the lens during generating. Blocks used for plastic lenses ("plastic-lens blocks") must not only hold the lens in place, they must 2 o also keep it from flexing (bending) during generating, fining, and polishing.
For that reason, plastic-lens blocks are generally considerably larger than glass-lens blocks. Since blocks for plastic lenses should be made as large as possiblefor each grinding situation, they are available in a variety of sizes ranging from approximately 55 to 6~ mm. Generally, the largest block that can be used on a given semifini~hed lens blank is chosen. It should be understood that "glass-lens blocks" are generally made from steel, not glass. They are normally used for blocking glass lenses. Neither are "plastic-lens blocks" made exclusively from plastic. Such blocks are normally made from alllmimlm.

- WO 97/10924 PCT~US96/14668 When a lens has been blocked using a metal alloy, it can be deblocked through shock deblocking or hot-water deblocking.
Shock deblocking of plastic lenses is done with a ring that is placed around the outside of the lens block on the front surface of the lens. It is deeper than the block, so when the lens and block are turned block side down, the ring may be struck against a flat surface. The block drops off the lens from the shock.
Hot-water deblocking is a commonly used technique that utilizes a hot-water bath. The temperature of the water is kept below the boiling point. The blocked lenses are placed on a rack, which is lowered into the water. With the lens under water, the alloy begins to melt and drips to the bottom of the tank.
There is a valve at the bottom of the tank through which the liquid alloy can bedrained off from time to time. After deblocking, the blocks and lenses are removed from the rack, the surface tape removed, and the lenses cleaned.
Attempts have been made to use less toxic materials in place of the toxic metal alloy. For example, materials comprising low molecular weight thermoplastic polymers and resins have been tried. Unfortunately, some of these compositions exhibit generally poor physical plupelLies (e.g., they are relatively brittle and of little cohesive or tensile strength). Others are very soft 2 o and waxy (or become soft and waxy during use), and are prone to flexing which could cause lens distortion during processing. In addition, some of these compositions are also very tacky and messy to work with and do not directly adhere well to glass lenses. Cleaning of these tacky compositions from lens blanks can be very time con~llming and significantly increase the cost of the 2 5 lens processing operation. Also, current wax compositions tend to be heat sensitive at temperatures encountered during normal processing conditions (e.g., grinding and polishing). Materials that are sensitive to normal operatingtemperatures (e.g., those materials that soften signific~ntly at those temperatures) are undesirable for use in this application. Also, some of the wax - W O 97/10924 PCT~US96/14668 based materials are not recommended for use in this application. Also, some of the wax based materials are not recornmended for use with glass lenses or cannot be used in the presence of petroleum based lubricants.

Smnm~ry We have discovered blocking compositions that have many advantages over traditional metal alloy materials. For example, the lens blocking compositions of the present invention are non-toxic, environmentally safe, and preferably biodegradable. The materials preferably can be used with existing 0 processing equipment and may be recycled.
In one embodiment an ophth~lmic lens block is provided that comprises a solidified mass of a thermoplastic blocking composition. The blocking composition may comprise a homopolymer or copolymer of epsilon-caprolactone, and preferably has a number average molecular weight of at least 3,000, a mean bending modulus of at least 69 MPa at 21 ~C, or a mean flexural strength of at least 1 MPa at 21 ~C. The composition is solid at 21 ~C and has asufficiently low melting or softening point such that the composition may be placed adjacent to an ophth~lmic lens blank while at its melting or softening point without ~1~m~ing the lens blank. The composition also has sufficient 2 o adhesion to a lens blank or to a lens blank coating or tape to hold an ophth~lmic lens during a generating procedure. Ophth~lmic lens blocking kits are provided that comprise the thermoplastic blocking composition and optionally a lens blank tape or coating and/or a pl~folllled base block. Preferred preformed base blocks comprise a front portion that has a negatively tapered peripheral edge.
2 5 The preferred preformed base block readily retains the thermoplastic blocking composition, yet can be easily separated from it after use. Preferred lens blanktapes are conformable and comprise a polymer backing that has both polar and non-polar moieties. By adjusting the ratio of polar and non-polar moieties, the adhesion to a thermoplastic blocking composition can be adjusted.

- WO 97/10924 PCT~US96/14668 In another embodiment, a method of holding an ophth~lmic lens blank is provided, comprising the steps of: providing a lens blocking composition as described above; heating the lens blocking composition to its melting or softening point; providing a blocking material receiving cavity against the lensblank; forming the ophth~lmic lens blocking composition into the receiving cavity; and allowing the composition to solidify. Alternatively, a method of holding an ophth~lmic lens blank is provided, comprising the steps of:
providing an ophth~lmic lens block com~lisillg a solidified mass of a thermoplastic blocking composition, and preferably comprising a heat absorbing 0 material; heating the surface of the lens blocking composition to its melting or softening point; positioning a lens blank against the softened surface of the lens blocking composition; and allowing the composition to resolidify.

Brief Description of the D.~wi~
This invention will be better understood when taken in conjunction with the drawings wherein:
FIG. 1 is a perspective view of an ophth~lmic lens blank and a lens block;
2 o FIG. 2 is a side view of an ophth~lmi~ lens blank and a lens block, wherein the ophth~lmic lens blank and a lens block are attached using a lens blocking composition of the present invention;
FIG. 3 is an end view of the ophth~lmic lens blank and lens block of FIG. 2;
FIGS. 4a and 4b are side and end views of an ophthalmic lens blank and a lens block formed from a lens blocking composition of the present invention, FIG. 4c is a side view of an ophth~lmic lens blank and a mold into which a lens blocking composition of the present invention may be injected to form a lens block;

FIGS. Sa and Sb are side and end views of an alternative ophth~lmic lens blank and a lens block formed from a lens blocking composition of the present invention;
FIGS. 6a and 6b are side and end views of an alternative ophth~lmic lens blank and a lens block formed in part from a lens blocking composition of the present invention and using a preformed base block;
FIGS. 7a and 7b are side and end views of an alternative ophth~lmic lens blank and a lens block formed in part from a lens blocking composition of the present invention and using a preformed base block;
lo FIG. 8a is a side view of an ophth~lmic lens blank and a lens block formed in part from a lens blocking composition of the present invention and using a preformed base block, FIG. 8b is a side view of the ophth~lmic lens blank and block of FIG. 8a, further showing a cross-section of a chill ring mold, FIG. 8c is a cross-sectional view of the block of FIGS. 8a and 8b;
FIG. 8d is a cross sectional view of a block similar to the block depicted in FIGS. 8a and 8b, but having an alternative location for the filling gate;
FIGS. 8e to 8g are side and end views of the preformed base block of FIG. 8c;
FIGS. 9e to 9g are side and end views of an alternative preformed base 2 o block having a scalloped outer edge; and FIGS. 10e to lOg are side and end views of a further alternative ulllled base block having a keyed outer edge.
This invention utilizes certain principles and/or concepts as are set forth in t_e claims appended to this specification. Those skilled in the lens generating 2 5 arts to which this invention pertains will realize that these principles and/or concepts are capable of being illustrated in a variety of embodiments which may differ from the exact embodiments utilized for illustrative purposes in this specification. For these reasons, the invention described in this specification is - W O 97/10924 PCT~US96/14668 not to be construed as being limited to only the illustrative embodiments but isonly to be construed in view of the appended claims.

Ur~less otherwise specified, the term "molecular weight" in this specification refers to "weight average molecular weight." (Mw = ~-,NjMj2/~:,N;
Mj) Although weight average molecular weight (Mw) can be determined in a variety of ways, with some differences in result depending upon the method employed, it is convenient to employ gel permeation chromatography. Standard 0 sample ~lep~dlion techniques should be observed. Molecular weight values reported by commercial suppliers of various materials are not always representedto be weight average molecular weight. The reported molecular weight is often presented in order to identify the particular material.
As used herein, the term "number average molecular weight" (Mn) refers to the total weight of all the molecules in a polymer sample divided by the total number of moles present. (Mn = ~-,NjMj/~jNj ) Although number average molecular weight can be determined in a variety of ways, with some differences in result depending upon the method employed, it is convenient to employ gel permeation chromatography.
2 o As used herein, the term "Z average molecular weight" (Mz) refers to a weighted average molecular weight defined by the equation Mz =
~jNjMj3/~jNjMj2. Although Z average molecular weight can be determined in a variety of ways, with some differences in result depending upon the method employed, it is convenient to employ gel permeation chromatography.
2 5 As used herein, the term "polydispersity" refers to the ratio of amz~terizll~' "weight average molecular weight" divided by its "number average molecular weight (MW/Mn) - W O 97/10924 PCTrUS96/14668 _g _ As used herein, the term "melting or softening point" refers to the temperature at which a material has changed from its cool state to its warm state and is capable of being shaped to conform to a lens blank.
As use herein, a "lens block" refers to the entire three-dimensional apparatus that is attached to the lens blank and used to "handle" the lens blankduring processing. This term includes any optional preformed base block and the thermoplastic blocking composition that attaches the preformed base block to the lens. This term does not include the lens itself or any lens surface protection tape or coating that is applied to the lens prior to blocking.

Detailed Description A variety of materials can be used in the ophth~lmic lens blocking compositions of the present invention. The materials described herein provide a blocking composition that has many advantages over traditional metal alloys.
For example, the materials are non-toxic, environmentally safe, and preferably biodegradable. The materials preferably can be used with existing processing equipment and may be recycled.
Preferred compositions COlllpli~t: a thermoplastic material, selection of which should be based in part on the desired end use for the composition (e.g., 2 o the type of lens being blocked, whether the composition is being used to form a block or attach a ~lerol,ned block, etc.) and the desired properties of the composition in the molten or softened ("warm") state and solid or hard ("cool") state.
The warm state is characterized by appreciable mass flow of the blocking composition under moderate pressure at some l~ ldture between above room temperature (preferably above about 35 ~C) and the maximum temperature that can be safely tolerated by the lens blank against which the composition is formed or applied (e.g., for a thermoplastic material preferably below about 85 ~C, more preferably below about 75 ~C). Notably, L,ler~ d thermoplastic materials of the present invention have a sufficiently high heat capacity that a Lt;lllpelature of 85 ~C~ can be tolerated. In contrast, metal alloys heated to 85 ~C might cause a plastic lens to melt or warp.
The cool state is characterized by sufficient ~ ,Lh and ~lirr~.~?s~ to permit a lens blank to be attached to a block, and by minim~l a~al~llL mass flow of the blocking composition under typical lens processing stresses and/or pressures at temperatures near or below room temperature.
The warm and cool state properties permit the blocking composition to be heated to a moderate temperature, shaped while warm to conform to the lens 1 o blank, and cooled or allowed to cool to form a substantially rigid block or blocking composition.
Suitable thermoplastic materials for use in the present invention include polyesters and polyurethanes such as those described in U.S. Pat. Nos.
3,382,202, 4,059,715, 4,182,829, 4,327,013, 4,361,538, 4,552,906 and 4,569,342; copolymers such as those described in U.S. Pat. Nos. 4,659,786 (e.g., polyester-polysiloxane block copolymers), 4,740,245 (e.g., ethylene vinyl acetate copolymers), and 4,768,951 (e.g., ionomer resins of ethylene copolymers); segm~nt~-l copolyesters and polyetheresters such as those described in U.S. Pat. Nos. 3,651,014, 4,173,506, 4,059,715, 4,066,600, 2 o 4,025,694, 4,430,429 and 4,552,906; ethylene vinyl acetate resins such as are described in European Published Pat. Application No. 0 359 135 and Kokai No.
Sho 63[1988]-96536; and polycaprolactones such as those described in U.S.
Pat. Nos. 5,066,231, 5,040,976, and 5,026,278. The disclosures of these references are herein incorporated by reference for their t~-~chings and disclosures of suitable thermoplastic materials.
Preferred thermoplastic materials have a weight average molecular weight of between about 5,000 and 100,000; more preferred materials have a weight average molecular weight of between about 10,000 and 70,000; and most preferred materials have a weight average molecular weight of between about 12,000 and 65,000. Preferred thermoplastic materials have a number average molecular weight of between about 3,000 and lO0,000; more preferred materials have a number average molecular weight of between about 3,000 and 50,000; and most ~l~felled materials have a number average molecular weight of between about 4,000 and 45,000. Preferred thermoplastic materials have a polydi,l)el.,iLy less than about 10; more plc:relled materials have a polydispersity less than about 8; and most preferred materials have a polydispersity less than about 6.
In one presently pler~lled embo~lim~nt, the thermoplastic material is a homopolymer or copolymer of epsilon-caprolactone. Preferred polycaprolactones have the general formula:

HO-- ~O~ J~ ~M~R~
O O
wherein Rl is an aromatic or a straight chain or branched aliphatic backbone, which can optionally contain one or more non-hllel rel ing substituents such as hydroxyl or amine groups, w is 1 if Rl is hydrogen, and w otherwise has an average value of about 1 to about 4, M is oxygen or -NR2- where R2 is hydrogen or a non-interfering aromatic or aliphatic group, and the average product of w times x is preferably greater than about 35.
Blends of polycaprolactones can also be employed. Compositions 2 o cont~inin~ a blend of high and low molecular weight polycaprolactones can have both a higher modulus and a lower viscosity than a composition con1~ining only one of the constituent polycaprolactones. In other words, the blend provides a synergistic combination of modulus and low viscosity. For example, blends of high molecular weight polycaprolactones (e.g., with a number average molecular weight greater than about 20,000) and low molecular weight polycaprolactones (e.g., with a number average molecular weight less than ~ about 20,000) may be used. If desired, more than one high or low molecular W O 97/10924 PCT~US96114668 -12-weight polycaprolactone may be used. For example, one may employ two dirrel~nL low molecular weight polycaprolactones and one high molecular weight polycaprolactone.

As used in this specification a "high molecular weight polycaprolactone"
refers to an epsilon-caprolactone homopolymer or copolymer whose number average molecular weight is at least about 20,000, and preferably at least about30,000. The high molecular weight polycaprolactones preferably have the general formula described above, wherein Rl, R2, w, and M are as previously defined and the product of w times x is greater than about 175. The product of w times xis more preferably at least about 250 and most preferably between about 250 and 440.
The low molecular weight polycaprolactone is an epsilon-caprolactone homopolymer or copolymer whose number average molecular weight is less than about 20,000, and preferably less than about l0,000. The low molecular weight polycaprolactones preferably have the general formula described above, wherein Rl, R2, w, and M are as previously defined and the product of w times x is less than about 175. The product of w times x is more preferably less than about 100,and most preferably between about 3 and 90.
2 o As a further guide, when the composition comprises a blend of high andlow molecular weight polycaprolactones, the weight ratio of high to low molecular weight polycaprolactones preferably is between about 9.5:0.5 to 0.5:9.5, more preferably between about 9: l to 1:9, most preferably 50:50 to 1.5:8.5, and will depend in part on the intended use for the composition.
2 5 The polycaprolactone can contain property-modifying or cross-linkable functional groups (for example, hydroxyl, acrylate, methacrylate, epoxy, isocyanato, or vinyl groups) if desired.
Preferred commercially available high molecular weight polycaprolactone polymers include "TONE P-767" polycaprolactone from Union Carbide Corp., - W O 97/10924 PCT~US96/14668 the "CAPA" polycaprolactones "640" (reported 40,000 molecular weight), "650" (reported 50,000 molecular weight) and "656" (reported 56,000 molecular weight) from Solvay Interox, and the various high molecular weight polycaprolactones available from Daicell Chemical Industry Co., Ltd. Other suitable high molecular weight polycaprolactone polymers include CAPA 630 from Solvay Interox.
Preferred commercially available low molecular weight polycaprolactone polymers include "TONE P-300" polycaprolactone (reported 10,000 molecular weight), "TONE 1270" polycaprolactone (reported 4,000 molecular weight), the 0 "TONE" polycaprolactone diols "0200" (reported 530 molecular weight), "0210" (reported 830 molecular weight), "0230" (reported 1,250 molecular weight), "0240" and "2240" (reported 2,000 molecular weight), and "0250"
(reported 3,000 molecular weight), "TONE" polycaprolactone triols "0301"
(reported 300 molecular weight), "0305" (reported 540 molecular weight) and "0310" (reported 900 molecular weight) from Union Carbide Corp., as well as the "CAPA" polycaprolactone diols "203" (reported 400 molecular weight) through "240" (reported 4,000 molecular weight), "CAPA" polycaprolactone triols "304" (250 molecular weight) and "305" (reported 540 molecular weight), and the "CAPA" polycaprolactone tetraol "316" (reported 1,000 molecular 2 o weight) available from Solvay Interox.
The amounts of high molecular weight and/or low molecular weight polycaprolactone, and the amounts of other ingredients in the blocking compositions of the invention, usually will be empirically selected. Selection should be based in part on the desired end use for the composition and the desired properties in the molten or softened ("warm") and solid or hard ("cool") states.For polycaprolactones, the warm state is characterized by an amorphous microstructure, and by appreciable mass flow under moderate pressure at some temperature between about 35 ~C and about 85 ~C, although a maximum of about 75 ~C is preferred. The cool state is characterized by a solidified semi-crystalline - W O 97/10924 PCT~US96/14668 polycaprolactone microstructure, and by minim~l, preferably no, app~ t mass flow under moderate pressure at temperatures below 21 ~C.
Blends of polycaprolactones with other suitable and compatible materials and polymers can also be employed. For example, a suitable polycaprolactone material may be blended with an ethylene vinyl acetate ("EVA") resin. Suitable EVA resins are described in European Published Pat. Application No. 0 359 135 and Kokai No. Sho 63[1988]-96536. Suitable commercially available EVA resins include the "ELVAX" resins shown below:
ELVAX ResIn Meltflowrate ~/~ Vinyl acetate 260 5.3-6.7 28 o These resins are commercially available from E.I. duPont de Nemours &
Company. "ULTRATHENE" EVA resins from Quantum Chemical Corp. and "ESCORENE" EVA resins from Exxon Chemical Corp. are also useful. Blends of resins can be used if desired.
In another embodiment, the thermoplastic material comprises a blend of the aforementioned EVA resins with a suitable wax material ~e.g., paraffinic hydrocarbons). Suitable wax materials include commercially available waxes such as "SHELLWAX" and "SHELLMAX" available from Shell Oil Company, Houston TX and "EPOLENE" waxes available from Eastman Chemical Products, Inc. Kingsport, TN. "SHELLWAX" waxes are available in a variety of grades having melt points from 50 to 84 ~C. Suitable "SHELLWAX" waxes include grades 100, 120, 200, 270, 300, and 700. "SHELLWAX" grade 200 is presently particularly preferred. Suitable "EPOLENE" waxes are available in a variety of grades having molecular weights from about 1,800 to 23,000.

CA 0222980l l998-02-l7 - W O 97/10924 PCT~US96/14668 The preferred arnounts of thermoplastic resin and wax in this embodiment of the thermoplastic blocking composition are as follows:

Ingredient Preferred weight % More ~lc~l~d weight %
Thermoplastic resin 30 to 90 50 to 80 Wax l0to70 20toS0 In yet another embodiment, the thermoplastic material is a segmented copolyester, preferably consisting essentially of a multiplicity of recurring intralinear long chain and short chain ester units connected head-to-tail through ester linkages. These are solid, non-tacky, strongly cohesive, solvent-free thermoplastic polymers. They consist essentially of from about S to 75 percent by 0 weight of amorphous ester units and 9S to 25 percent by weight of crystallizable ester units joined through the ester linkages (the term "crystallizable" as usedherein includes both crystalline ester units and units which are capable of becoming crystalline).
The crystallizable ester units in the copolyesters are of the formula:
-C(O)RlC(O)-OR2O- (forrnula I) and the amorphous ester units are of the formula: -C(O)R3C(O)-OR40- (formula II) wherein Rl is preferably the divalent radical rem~ininp; after removal of carboxyl groups from a dicarboxylic acid having a molecular weight less than about 300, more preferably, Rl consists of residues 2 o (rem~ining after removal of the carboxyl groups) of one or more diacids selected from saturated aliphatic dicarboxylic acids cont~ining from 4 to l0 carbon atoms (the residues thereof cont~ining from 2 to 8 carbon atoms) and, alternatively and less preferably, aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, 4-4'-benzophenone dicarboxylic acid, 4-4'-diphenylmethanedicarboxylic acid, 4-4'-diphenylether - W O 97/10924 PCT~US96/14668 dicarboxylic acid, 4,4'-diphenylthioether dicarboxylic acid and 4,4'-diphenylamine dicarboxylic acid;
R2 is preferably the divalent radical rem~ining after removal of hydroxyl groups from a low molecular weight diol having a molecular weight less than about 250, more preferably, R2 consists of residues (rem~inin~ after removal of the hydroxyl groups) of one or more saturated aliphatic diols co~ ioi.l~ from 2 to 12 carbon atoms;
R3 is preferably Rl, optionally R3 is Rs~ wherein R5 consists of the divalent radicals cont~ininp; from 22 to 50 carbon atoms which remain after removal of the carboxyl groups from saturated aliphatic dimer acids (i.e., the polymerized and hydrogenated product of two molecules of an ethylenically unsaturated fatty acid containing from about 12 to 26 carbon atoms, the dimer acid thus being saturated and cont~inin~ from 24 to 52 carbon atoms); and R4 is R2 or R6, wherein R6 consists of the divalent radicals rem~inin~ after removal of the hydroxyl groups from a long chain aliphatic diol having an average molecular weight of 200 to 4,000 (preferably 400 to 2,000, and more preferably 600 to 2,000), provided that at 2 o least one of R3 and R4 in each amorphous ester unit is R5 or Ro~
and provided that when Rl is aromatic, R2 contains from 6 to 12 carbon atoms and the amorphous content is 50-75 percent by weight.
The copolyesters preferably have DTA melting temperatures of from about 25~ to 2 5 150~C and inherent viscosities of preferably at least 0.5 dl/g (this and the other inherent viscosities herein are measured in 0.3 g/dl solutions of polymer in chloroform at 25~C). Usually the inherent viscosities of the copolyesters are not -more than 1.5 dl/g at 25~C.

The copolyesters of the present invention are preferably substantially linear and of relatively high strength. The linear copolymers are prepared from short and long chain precursors which are difunctional with respect to carboxyl and hydroxyl, for example organic diols (glycols) and dicarboxylic acids. The diacid precursors cont~ininp Rl are often referred to herein as short chain diacids, the diol precursors cont~ininP R2 as short chain diols, the diacid precursors contz~ining R5 as long chain diacids and the diol precursors contz-inin~ R6 as long chain diols. The carboxyl and hydroxyl functions most often appear in the precursors as the free acid and free base but can also appear as simple derivative functions such as esters, acid chlorides or anhydrides if desired.
The relative amount of crystallizable and amorphous units is ~ietermined by the precursor charge. Most frequently the copolyesters are reaction products of a long and a short chain precursor of one functionality and a short chain precursor of the other functionality. In case of such a stoichiometrically balanced charge of three monomers, the weight percentages of amorphous and crystallizable units can be calculated exactly (this is also true where there are more than three monomers but of only three types, e.g., two short chain diacids, one short chaindiol and one long chain diacid but no long chain diol, etc.). However, if monomers of all four types are included in the charge, the relative amounts of 2 o amorphous and crystallizable units are not exact but can be expressed as falling between two values (the range being quite narrow). Thus, to calculate the minimum amorphous content in such a copolyester, it is assumed that the maximum possible reaction occurs between the short chain diol and short chain diacid (thus m~imi7ing the content of crystallizable units). To calculate the 2 5 m~imnm amorphous content, it is assumed that the maximum possible reaction occurs first between the short chain diacid and the long chain diol and between the short chain diol and the long chain diacid~ the rem~ining reactants after those reactions (if any remain) reacting with one another.

The amorphous and crystallizable units of the copolyesters can alternate in the polymer chains or they can appear in blocks of the same type and this canbe controlled to some extent by the process of pl~,al~Lion. For example, prepolymers of crystallizable and/or amorphous units can be prepared separately thus assuring larger blocks of one type or the other or, as is the usual practice, the precursors (monomers) can be charged directly and simultaneously to the reactionvessel.
The amorphous blocks of the copolyesters of the invention are most often composed of ~ltern~tinp long chain diol and short chain diacid residues, but this is not nec~ccz~rily the case. Although it is possible that a long chain diol and a long chain diacid could react alternately to form blocks of several repeating units, this is unlikely and, at any rate would have little effect on the ~lo~cl Lies of the resulting polymer. The end groups of the copolyesters can be of a single functionality, if an excess of one precursor is included, or can be a mixture if the charge was stoichiometrically balanced.
The short chain diacids can be saturated aliphatic acids cont~inin~ from 4 to 40 carbon atoms (including unbranched, branched, or cyclic having S to 6 atoms in a ring) and/or aromatic acids cont~ining from 8 to 15 carbon atoms.
Examples of suitable aliphatic acids are succinic, glutaric, adipic, pimelic, 2 o suberic, azelaic, sebacic, 1,3- or 1,4-cyclohexanedicarboxylic, 1,3-cyclopentanedicarboxylic, 2-methylsuccinic, 2-methylpentanedioic, 3-methylhexanedioic, carbonic, oxalic, itaconic, diethylmalonic, fumaric, citraconic, allylmalonate, 4-cyclohexene-1,2-dicarboxylate, 2,5-diethyladipic, 2-ethylsuberic, 2,2,3,3-tetramethylsuccinic, decahydro-l,S- (or 2,6-) naphthylene 2 5 dicarboxylic, 4,4'-bicyclohexyl dicarboxylic, 4,4'-methylenebis(cyclohexyl carboxylic), 3,4-furan dicarboxylate, and l,1-cyclobutane dicarboxylate acids and the like. Other representative dicarboxylic acids include terephthalic and isophthalic acids, bibenzoic acid, substituted dicarboxy compounds with benzene nuclei such as bis(p-carboxyphenyl) methane, p-oxy(p-carboxyphenyl) benzoic - W O 97/10924 PCT~US96/14668 acid, ethylene-bis(p-oxybenzoic acid), 1,5-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 2,7-naphthalene dicarboxylic acid, phen~nthralenedicarboxylic acid, anthralene dicarboxylic acid, 4,4'-sulfonyl dibenzoic acid, etc.
and Cl-C10 alkyl and other ring substitution derivatives thereof such as halo, alkoxy or aryl derivatives.
The short chain diols include branched, unbranched, and cyclic aliphatic diols having 2 to 15 carbon atoms, such as, for example, ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 2-methyl-2,4-pentanediol, 1,6-hexanediol, 1,8-octanediol, 0 cyclobutane- 1 ,3-di(2' -ethanol), cyclohexane- 1 ,4-dimethanol, 1,1 O-decanediol, and 1,12-dodecanediol. Preferred are diols with 2-15 carbon atoms such as ethylene, propylene, isobutylene, tetrarnethylene, pentamethylene, 2,2-dimethyltrimethylene, hexamethylene and decamethylene glycols, dihydroxy cyclohexane, cyclohexane dimethanol, resorcinol, hydroquinone, 1 ,5-dihydroxy naphthalene, etc. Especially preferred are aliphatic diols cont~inin~ 2-8 carbonatoms. Included among the bis-phenols which can be used are bis(p-hydroxy) diphenyl, bis(p-hydroxyphenyl) methane, and bis(p-hydroxyphenyl) propane.
The chemical structure of the long chain diol is not critical. Any substituent groups which do not interfere with the polymerization reaction to 2 o form the copolyester can be present. Thus, the chain can be a single divalent acyclic or alicyclic, hydrocarbon group, poly(alkylene oxide) group, polyester group, a combination thereof, or the like. Any of these groups can contain substituents which do not interfere to any substantial extent with the polymerization to form the copolyester used in accordance with this invention.
2 5 The hydroxy functional groups of the long chain diols used to prepare the copolyesters should be tt?rmin~l groups to the extent possible.
Suitable long chain diols include poly(oxyalkylene)glycols in which the aLkylene group contains from 2 to 9 carbon atoms, preferably from 3 to 8 carbon atoms and more preferably from 2 to 4 carbon atoms. Among these compounds are poly(aLIcylene oxide) glycols and polyether glycols such as poly(oxyethylene)glycols having molecular weights of about 200, 600, 1500, and 2000, poly(~xy~ro~ylene)glycols, having molecular weights of about 425 and 1800, poly(oxytetramethylene)glycols, poly(oxypentamethylene)glycol, poly(oxyhexamethylene)glycols, poly(oxyheptamethylene)glycols, poly(oxyoctamethylene)glycols, poly(oxynonamethylene)glycols, poly(l,2-butylene oxide)glycol, random or block copolymers thereof, for example, glycols derived from ethylene oxide and 1,2-propylene oxide and poly-formals ~lepaled by reacting formaldehyde with glycols, such as pentamethylene glycol, or 0 mixtures of glycols, such as a ~ lule of tetramethylene and pentamethylene glycols. Also included are poly(lactone)glycols, e.g., poly(caprolactone)glycol;poly(oxyalkylenecarbonate)glycols, e.g., poly(oxyethylenecarbonate)glycol; and glycols con~ining a hydrocarbon main chain, e.g., hydroxy-terrninzlt~d polybutadiene.
The copolyesters can be prepared by conventional polycon~len~tion polyester-forming reactions wherein one or more short chain diacids and/or long chain diacids or their equivalents (e.g., volatile alcohol esters, acid chlorides, or anhydrides of the diacids) are caused to react with an equivalent amount of one or more short chain diols and/or long chain diols. When copolyesters having an acid2 o value of no more than about 2 (indicating substantially complete reaction) and relatively high molecular weight are desired, it is preferable that the polyester reaction be carried out in the presence of a suitable catalyst.
The choice of catalyst depends on the starting materials. Thus, for simple esterification of a short chain diacid with a short chain diol and a long chain diol, 2 5 the diacid alone may preferably function as esterification catalyst. Optionally, however, one may use as a catalyst a compound having an ionization constant greater than about 10-3, such as, for example, p-t-butylbenzenesulfonic acid. For esterification by ester interchange, an ester interchange catalyst is used. Suitable catalysts include, for example, m~ng~nous acetate, calcium acetate, zinc acetate, sodium methoxide, antimony oxide, antimony glycoxide, tetraalkyltit~n~tes7 complex tit~n~tes such as magnesium he~lkyltitanates or other suitable ester interchange catalysts as described in the literature relating to the preparation of polyesters.
Suitable thermoplastic materials have a melting or softening point above about 35 ~C. Preferred thermoplastic materials have a melting or softening point between about 40 and 85 ~C, more preferably between about 45 and 75 ~C, and most preferably between about 50 and 70 ~C. A composition has reached its melting or softening point when it has changed from its solid state 0 and has become capable of appreciable mass flow under moderate pressure.Preferred compositions are capable of being injection molded using standard blocking all~aldLus. Typically, the pressure employed in commercial blocking apparatuses is about 69 kPa (10 psi). Preferred compositions for forming blocks are able to fill the lens block cavity in less than about 2 mimltes using standard equipment, such as an "OPTEK" 200 blocker from Optek Division, Associated Development Corp., Pinellas Park, FL. More preferably, the cavity can be filled in less than about 1 minute, and most preferably, the cavity can be filled in less than about 30 seconds.
A common physical property measured in the plastics industry to 2 o characterize a material's flow properties under pressure is its viscosity. Suitable compositions have a viscosity that is low enough such that the material may be easily molded when in its warm state to the shape of the lens blank. Preferred materials have a viscosity that is low enough such that the material may be injection molded within a reasonable time under a reasonable pressure. The composition's viscosity is preferably not so low that the composition undesirably "flashes" when injection molded (i.e., undesirably flows through cracks between the cavity and the lens blank). In addition, when the composition contains solid adjuvents, such as fillers, the warm state viscosity - should preferably be high enough that the filler does not undesirably settle.

Preferred blocking compositions for use in the present invention with traditional blocking machines have a shear viscosity (measured at the desired temperature of use using a Rheometrics Dynamic Analyzer (RDA-II) having 25 mm parallel plate geometry and a steady shear rate of 1 s-l) of between 3 and 500 Pascal seconds (Pa s). More ~ler~ d blocking compositions for use in the present invention with traditional blocking machines have a shear viscosity of between 3 and 100 Pa s. Most pler~lled blocking compositions for use in the present invention with traditional blocking machines have a shear viscosity of between 3 and 30 Pa s.
The blocking composition should preferably be hard enough at its use temperature to function in the manner intended. For example, the composition, when used to form a complete block, should be hard enough to with~t~nrl the forces and stresses imparted during the typical lens processing procedure, including any forces and stresses imparted tO the composition during mounting and unmounting from the lens processing machinery as well as any forces imparted to the composition during the actual grinding or fini~hin~ operation.
Compositions that deform or flow appreciably during these operations may be unsuitable. Suitable thermoplastic materials are solid or "hard" at temperaturesnear or below room temperature. Preferred thermoplastic materials are solid at 2 o temperatures below about 40 ~C, more pl~r~;lled thermoplastic materials are solid at temperatures below about 45 ~C, and most preferred thermoplastic materials are solid at temperatures below about 50 ~C.
The hardness of the blocking composition may be measured by the material's bending modulus. This property is conveniently measured using the 2 5 three-point bending technique described in ASTM D790-86. Suitable blocking compositions have a mean bending modulus of at least 34.4 MPa, preferably at least 69 MPa, more preferably at least 138 MPa, and most preferably at least 276 MPa, when tested at 21 ~C according to ASTM D790-86 (using at least 3 specimens per test).

- WO 97/10924 PCT~US96/14668 Preferred solid blocking compositions exhibit a Shore "A" hardness of at least 40 when tested at 21 ~C using the technique described in ASTM D2240 (using at least 3 specimens per test). More preferred compositions have a Shore "A" hardness of at least 70, and most ~Icfell~d compositions have a Shore "A"
~ 5 hardness of at least 90. If the Shore "A" value of a particular material is out of scale then Shore "D" may be employed. More preferred solid blocking compositions exhibit a Shore "D" hardness of at least 20 when tested at 21 ~C
using the technique described in ASTM D2240 (using at least 3 specimens per test). Most ~lcrt;llcd compositions have a Shore "D" hardness of at least 25, and oy~llllum compositions have a Shore "D" hardness of at least 30.
Alternatively, the hardness of the composition may be tested using a nanoindentation technique, as described in Example 2. Preferred compositions have a nanoindentation hardness of at least 1 GPa, more p~crc"ed compositions have a nanoindentation hardness of at least 2 GPa, and most ~,cre"cd compositions have a nanoin~lent~tion hardness of at least 4.5 GPa.
The blocking composition should preferably have enough cohesive strength and/or tensile strength to function in the lllallllcl int~onrlPcl. For example, the composition, when used to form a complete block, should have enough cohesive strength to with~t~n(l the forces and stresses imparted during 2 o the typical lens processing procedure, including any forces and stresses imparted to the composition during mounting and unmounting from the lens processing machinery as well as any forces imparted to the composition during the actual grinding or fini~hin~ operation. Compositions that fall apart, crack,or shatter during these operations are llnsllit~ble.
2 5 The strength of the blocking composition may be conveniently measured using the three-point bending technique described in ASTM D790-86. Preferred blocking compositions have a mean flexural strength at 21 ~C of at least 1 MPa, more preferably at least 2 MPa, most preferably at least 4 MPa, and optimally at least 6.8 MPa, when tested according to ASTM D790-86 (using at least 4 specimens per test).
The blocking composition preferably should be dimensionally stable and should m~int~in the desired geometric ~ nmPnt of the lens blank to the processing machine. Compositions that are either too soft or that creep under typical operating stresses may not m~int~in the nl-cess~ry ~lignm~nt of the lensto the reference guides on the back of the block. These errors will be ilnpalLedto the lens and may cause imprecise machining of the lens.
Preferred blocking compositions are relatively dimensionally stable 0 when heated over a temperature range of 0 ~C to near the melting temperature of the composition. Example 1 describes a Thermal Mechanical Analysis technique that may be used to measure a material's dimensional change upon heating. Preferred blocking compositions exhibit less than 2.9 % change in dimension over a teln~ dture range between 0 ~C and three degrees less than the material's melting ~elll~eldture, when tested according to the procedure described in Example 1. More ~l~r~ d blocking compositions exhibit less than 2 % change in ~ n~ion7 and most pl~r~ d blocking compositions exhibit less than 1.5 % change in dimension.
Preferred blocking compositions are also relatively dimensionally stable 2 o when cooled over a temperature range of near the melting temperature of the composition to 21 ~C. Preferred blocking compositions exhibit less than a 5 %
change in volume when cooled from the material's melting temperature to 21 ~C. More ~l~felled blocking compositions exhibit less than 4 % change in volume, and most pl~fell~d blocking compositions exhibit less than 3 % change in volume. Optimally, the blocking composition can with~t~n~l normal changes in dimension without cracking or crazing.
The blocking composition is preferably non-tacky at 21 ~C. Materials which are tacky at room temperature tend to be difficult to work with and messy. Tacky materials also tend to become cont~min~tp~l with lint and dust.

- W O 97/10924 PCT~US96/14668 These cont~minznt~ can adversely affect the ability of the composition to be recycled. Tackiness may be measured using a probe tack test as described in ASTM D2979-88 and Example 2 below. Preferred compositions have a mean peak value of less than 800 g, more preferred compositions have a mean peak value of less than 400 g, when tested as described herein.
The blocking composition should preferably adhere to the lens blank (or to a coating or tape applied to the lens blank) with a sufficient strength to avoid nnint~n~lç~ detachment of the lens during processing, yet preferably allow deblocking of the lens using traditional shock deblocking or hot-water deblocking methods. Thus, a preferred balance of adhesion should be achieved.
One method of measuring adhesion is described in Example 2. This method utilizes a tensile testing m~hin~ to shear a small button of material from the surface of a substrate. Using this method, preferred blocking compositions have a mean shear adhesion value, of at least 6.5 kg/cm2, more preferably between 6.5 and 25 kg/cm2, and most preferably bet~,veen about 8 and 20 kgtcm2.
Another method of assessing whether a particular blocking composition achieves the n~cess~ry balance of adhesion between the blocking composition and the lens blank (or to a coating or tape applied to the lens blank) is to 2 o perform a shock deblocking test using a standard commercial lens block. For this test, a 70 mm plastic lens with a 2.0-2.4 mm center thickness, plano, finished uncut, "RLX PlusTM Scratch Rçsi~tslnt, Finished Lens in Hard Resin" from Signet Armorlite, Inc. is optionally covered with a surface protective tape. A brass blocking ring is placed on a blocker (e.g., OPTEKTM Model 200 Blocker) and a 56 2 5 mm diameter Coburn Block from Coburn Company is placed into the ring such that the inlet in the block fits snugly over the rubber nozzle. The block is then centered on the lens and slowly filled with molten blocking composition. The blocked lens assembly is allowed to set for l 0 to l 5 seconds after filling, in order for the resin to harden and form a good bond to the taped lens. The blocked lens is removed from the blocker and allowed to set for 1 hour before deblocking. Theblocked lens is placed into the deblocking ring and the lens is taped to the deblocking ring using 1.27 cm wide filament tape. With the blocking tool facing dow,lw~u.l, the blocked lens is placed in a hollow tube. The diameter of the tube is much greater than the blocking tool and the tube is sufficiently thick to abruptly stop the lens by its perimeter. The blocked lens assembly is dropped starting at 2.54 cm height and raised in 2.54 cm increments until the block separated from the tape or until 15.24 cm in height, then, raised and dropped in5.08 cm increments up to 91.44 cm. The height in centimeters at which the block o released from the tape is recorded as the deblock value. Using this method, p~c:fe~ d blocking compositions have a deblock value of between 5 and 56 cm, more preferably between 7 and 45 cm, most preferably between about lO and 35 cm, and optimally between about 14 and 20 cm.
The blocking compositions of the present invention can contain a wide variety of adjuvents depending upon the desired end use. Suitable adjuvell~
include solvents, ~ ntc, plasticizers, pigments, dyes, inorganic and organic fibrous or particulate reinforcing or extending fillers, nucleating agents, thixotropic agents, in~licat->rs, inhibitors, stabilizers, UV or IR absorbers, and the like.
2 o Viscosity modifiers and/or performance modifiers (hereinafter "modifiers") are particularly preferred optional adjuvents for use with the thermoplastic blocking compositions of the present invention. These modifiers may be added to the blocking composition as needed to either enhance or adjust certain warm state ~loL)ellies, such as the viscosity of the heated composition (e.g., to facilitate flow rates during cavity filling) and/or to enhance or adjust certain cool state properties, such as resistance of the material to cracking upon cooling. Preferably, the modifiers are essentially solid at room temperature (soas to not undesirably provide a "greasy" feel to the blocking composition). The modifiers also preferably m~int~in their compatibility with the blocking composition during their transition to or from the cool state to the warm state.Most preferably, the modifier does not undesirably phase separate during these transitions.
Suitable modifiers include carboxylic acids of the form CH3(CH2)nCOOH, where n is preferably between about 10 and 16 for blocking compositions that have a melting temperature between about 45 and 75 ~C. In general, the number of -CH2- groups may be adjusted to complement the particular thermoplastic blocking composition being used. Higher numbers of these groups tend to increase the melting temperature of the acid. Thus, when the melting temperature of the blocking composition being used is higher than 75 ~C, the number of -CH2- groups can be larger. Conversely, acids having lower numbers of -CH2- groups will tend to be liquids at room temperature.
Their use in a blocking composition may result in a blend that has a somewhat greasy feel. A particularly pler~lled carboxylic acid modifier for use with polycaprolactone polymers and blends of polycaprolactone polymers is 1-oct~-ltoc~noic acid ("stearic acid," available from Aldrich Chem. Co., Milwaukee, WI).
Suitable blocking compositions have been developed that incorporate between about 0 and 40 weight percent carboxylic acid modifier. More 2 o preferably, polycaprolactone based blocking composition comprise betweenabout 1 and 25 weight percent carboxylic acid modifier, and most preferably, between about 5 and 20 percent carboxylic acid modifier.
Other suitable modifiers include monohydric and polyhydric alcohols.
Suitable alcohols include straight chain alcohols, branched chain alcohols and 2 5 glycols. Preferred monohydric straight chain alcohols have the general form CH3(CH2)nOH, where n is preferably between about 11 and 19 for blocking compositions t'nat have a melting temperature between about 45 and 75 ~C.
More preferably, n is between about 13 and 17 for these compositions. In - general, the number of -CH2- groups may be adjusted to complement the particular thermoplastic blocking composition being used. Higher numbers of these groups tend to increase the melting temperature of the alcohol. Thus, when the melting temperature of the blocking composition being used is higher than 75 ~C, the number of -CH2- groups can be larger. Conversely, alcohols having lower numbers of -CH2- groups will tend to be liquids at room ~ laLule. Their use in a blocking composition may result in a blend that has a somewhat greasy feel. In general, suitable branched chain alcohols may have a somewhat larger number of -CH2- groups than straight chain alcohols.
Preferred branched chain alcohols have between 10 and 20 carbon atoms.
Particularly L~lc;r~lled monohydric straight chain alcohol modifiers for use with polycaprolactones and blends of polycaprolactones include 1-octz~-iec~nol ("stearyl alcohol," available from Aldrich Chem. Co., Milwaukee, WI), l-hex~rl.oc~nnl ("cetyl alcohol," available from Aldrich Chem. Co.), 1-tetr~ c~nol ("myristyl alcohol," available from Aldrich Chem. Co.), and 1-dodecanol ("dodecyl alcohol," available from Eastman Chem. Products, Inc., V~gspor,, TN).
Suitable blocking compositions comprise up to about 60 weight percent alcohol modifier. Preferred compositions comprise between about 1 and 60 weight percent alcohol modifier. More preferably, polycaprolactone based 2 o blocking compositions comprise between about 5 and 45 weight percent alcohol modifier, and most preferably, between about 15 and 40 percent alcohol modifier.
Preferred polyhydric alcohols include polyethylene gylcols having the general form H(OCH2CH2)nOH, where n is between 20 and 185, and 2 5 polyethylene glycol ethers having the general for~n R(OCH2CH2)nOR, where R
is typically hydrogen or a straight-chain or branch-chain alkyl group having between 1 and 10 carbon atoms and where n is between 17 and 116. More preferably, one R group is hydrogen and the other R group is selected from the group consisting of CH3 and CH2CH3.

- W O 97/10924 PCT~US96/14668 Most preferably, the polyhydric alcohol is a polyethylene glycol.
Preferred polyethylene glycols have a weight average molecular weight between about 900 and 8,000. More preferably, for use with polycaprolactone based blocking compositions the polyethylene glycol has a weight average molecular weight between about 1,000 and 3,400. A presently ~l~r~l.ed polyethylene glycol is available from Aldrich Chemical Company, Milwaukee, WI, and has a molecular weight of about 1,500.
Other suitable polyhydric alcohols include polyethylene glycol methyl ethers having a weight average molecular weight between about 750 and S,000.
More preferably, for use with polycaprolactone based blocking compositions the polyethylene glycol methyl ether has a weight average molecular weight between about 1,000 and 3,400. A presently preferred polyethylene glycol methyl ether is available from Aldrich Chemical Company, Milwaukee, WI, and has a molecular weight of about 2,000.
If desired, blends of two or more modifiers may be employed. For example, combinations of stearic acid and stearyl alcohol; stearyl alcohol and yli~lyl alcohol; stearyl alcohol, myristyl alcohol and dodecyl alcohol; and stearyl alcohol, myristyl alcohol and polyethylene glycol have been found to be beneficial. Other combinations will likely also be suitable. The blend should bechosen to ~,p~ the pl-,pellies of the blocking composition for its desired use. Myristyl alcohol has been found to be particularly compatible with polycaprolactone based blocking compositions and has also been found to help make other less compatible modifiers compatible with polycaprolactone. When blends of two or more modifiers are employed, suitable blocking compositions 2 5 comprise up to about 60 weight percent of the blend of modifiers. Preferably, polycaprolactone based blocking compositions comprise between about 1 and 60 weight percent of the blend of modifiers, more preferably between about 15 and 50 weight percent of the blend of modifiers, and most preferably, between ~ about 15 and 40 percent of the blend of modifiers.

Preferred fillers for use in the present invention comprise inorganic or organic, particulate or fibrous materials which are substantially insoluble in the continuous phase. Filler morphologies may include spheres, bubbles, exp~n~l~ble bubbles, particulate materials, fil~m.ont~, microfibers, flakes and platelet type materials, as well as combinations of these. The fillers may have a solid, porous, or hollow structure.
Suitable inorganic filler materials include glass, amorphous and crystalline silica, soda lime borosilicate, amorphous sodium/pot~sillm/~ min~-m silicate glass, ~lllmin~, iron oxides, calcium lo m~t~ilir~t~, calcium carbonate, calcium sulfate (in either a particulate or microfiber form), kaolin, mica, talc, barium sulfate, boron fibers, carbon fibers, glass fibers, ground glass fibers, flake glass, mtot~llic fibers, feldspar, barium ferrite, ~ ll oxide, ceramics and the like. Preferred inorganic filler materials include glass and ceramic bubbles such as: Scotchlite~ brand glass bubbles H50/10000 EPX, HS0/10000 (acid washed), K-46, and S60/10000 (available f~om 3M}; ~x~.endospllere~ brand SG, CG, Sr-12 (a-vailable lrOm PQ
Corp.); Zeeosphere~ brand 200, 400, 600, 800, and 850 (available from 3M);
ZeoliteTY W1000, W1012, W1300, W1600, G3400, and G3500 (available from 3M); Dicaperl~ brand HP-900 and HP-920 (available from Grefco) and Sil-2 o Cell~ brand Sil-35/34, Sil-32, Sil-42, and Sil-43 (available from Silbrico Corp., Hodgkins, IL 60525). DicaperlTM brand HP-820, HP-720, HP-520, HP-220, HP-120, HP-900, HP-920, CS-10-400, CS-10-200, CS-10-125, CSM-10-300, and CSM-10-150 (available from Grefco, Torrance, CA), and ceramic particles such as Ceramcel~ (available from Microcel Tech. Inc.) may also be suitable, particularly when blended with other fillers. Colored pigment fillers are also suitable. Blends of these fillers may also be suitable.
Suitable organic fillers include fillers comprised of thermoplastic or thermoset organic materials ~r both as well as composite filler materials comprising the aforementioned organic materials as matrix and inorganic micro-- W O 97/10924 PCTrUS96/14668 inclusions dispersed therein. Preferred organic fillers are insoluble in the blocking composition. Suitable thermoplastic filler materials include polyolefins such as Primax brand UH-1080, UH-1060 and UH-1250 (available from Air Products & Chemicals - Allentown, PA), polyesters (e.g., poly(ethylene terephth~ te), hereinafter referred to as "PET"), polyamides, polyimides, ~olyaçr~la~es, p~)ly~rbQnatç5 pol~ ane and the like including copol~vmers of the aforementioned materials. Suitable thermoplastic filler materials also include exr~ntl~ble bubbles such as F.xp~nrel 461 DE 20 microspheres (available from Nobel Industries). Suitable thermoset filler materials include epoxies, aldehydeo condensation products (e.g., Ucar Thermoset microballoons BJO-0950, BJO-0820, BJO-0900, BJO-0840, BJO-09300 available from Union Carbide, Danbury CT), acrylates, and methacrylates. Preferred organic filler materials include polyethylene microspheres (available from Air Products & Chemicals -Allentown, PA).
Preferred particulate fillers have an average particle ~ m~t~r between S
and 500 microns, more preferably the particulate fillers have an average particle m~ter between 20 and 200 microns, most preferably the particulate fillers have an average particle tii~m~ter between 30 and 120 microns. As used herein, "average particle diameter" is defined as the diameter of a sphere of the same 2 o volume as the particle.
Microfibers may be added to the blocking composition to enhance integrity or composite strength. Preferred fibers for use in the present invention have an average length between 25 and 5,000 microns, more preferably the fibers have an average length between 30 and 1,000 microns, most preferably 2 5 the fibers have an average length between 30 and 500 microns. Microfiber fillers such as those described in U.S. Patent Application No. 08/008,751, which is herein incorporated by reference, may also be useful alone or in combination with other particulate fillers or fibers.

- WO 97/10924 PCT~US96/14668 Suitable concentrations of filler in the blocking composition (i.e., "filler loading") will vary depending on the buLk density of the filler, the specific gravity of the filler and particular thermoplastic blocking composition employed, and the desired h~n~lling property of the composition. A suitable filler loading is determined by selecting a level which is sufficiently high to ensure adequate strength but not so high that the composition becomes too viscous to flow and adapt to the lens surface when softened.
The composition should remain substantially homogeneous (that is, it should not undergo macroscopic phase separation or filler sedimentation) during o use and more preferably during prolonged storage prior to use. The composition preferably should retain its desired physical L~lop~lLies even if repeatedly cycled between the warm and cool states. Thus the selection of ingredients can be guided in part by a desire to preserve homogeneity and thermal reversibility.
The ingredients in the blocking composition can be blended by hand or by mech~nir~l mixing. The ingredients preferably are warmed sufficiently to melt the thermoplastic material, but if desired can be mixed at lower temperatures. Any suitable mixing device can be used, including kettles equipped with a mechanical stirrer, extruders, rubber mills, and the like.
2 o The blocking composition can be put up in a variety of forms including preformed blocks, sheets, ropes, pellets, powders and the like. The composition can be shaped in a variety of ways including extrusion, injection molding and web proce~cing using a coating knife or rollers. The composition can be sold ullwl~ed, loosely wrapped in a package, or packaged in tubes, syringes, and 2 5 the like.
The blocking composition can be converted from the cool state to the warm state by using a variety of energy sources. The composition can be immersed in a heated bath conf~ining a suitable inert liquid (e.g., water or a fluoroch~mic~l fluid) that will not dissolve or swell the composition in either its - W O 97/10924 PCT~US96/14668 cool or warm states. The composition can also be softened using heat sources such as a melting pot, hot air gun, hot plate, conventional oven, infrared heater, or microwave oven. The composition can be encased in a plastic pouch, syringe or other container which is in turn heated or is subjected to one or more of theabove-mentioned heating methods.
Transforming the blocking composition from a warm state to a cool state requires loss of thermal energy and can be carried out using a variety of cooling techniques. Cooling can take place under ambient conditions in the presence of air only. Cooling can also be expedited using forced air, cold water, ice, or heat 0 sinks such as chilled "cold pack." In one presently ~lefellcd method, the blocking composition is cooled using "cooling" or "chill" rings. The rings are shaped to ~ullound the block and circulate a cool liquid, such as chilled water,thus ~ ipating heat from the blocking composition.
In one embodiment of the present invention, a composition, preferably comprising a "heat absorbing material," is ~l~r(Jlllled into a "stock" lens block (e.g., by injection molding techniques). The generally concave surface of the stock lens block is then heated, for example, using an infrared (IR) heat source, to melt the surface of the ~lcfo~ ed block to a depth sufficient to allow the plc~rolllled block to conform to the surface of the lens blank. A lens blank is 2 o then positioned against the softened surface of the block and the heated surface is allowed to cool. AlL~ln~Lively, the composition cont~ining the heat absorbingmaterial may be provided in a powdered, pelleted or sheet form and placed in the cavity of a block. The composition may then be heated as described above.
This method has the advantage that less material needs to be heated.
Consequently, the procedure is very fast (sufficient surface heating can occur in less than about 10-15 seconds). In addition, the material is not stored in its warm state for a prolonged period (such as would occur in a melting pot). Thus, compositions having less long~--term stability in the warm state may be employed.

Suitable "heat absorbing materials" include carbon black, and other inorganic pigments and fillers. The heat absorbing materials are preferably present in an amount sufficient to speed the heating of the blocking composition. Preferred compositions contain up to about 70 % by weight of a heat absorbing material. More ~lcre~ d compositions contain between about 1 and 20 % by weight of a heat absorbing material, most preferred compositions contain between about 5 and 15 % by weight of a heat absorbing material. The amount of the heat absorbing material may be empirically selected to adjust the depth of the softening layer for a given h~ siLy IR source and a given exposure 1 o time.
If desired, a preformed stock lens block base can be fitted with a layer of a blocking composition of the present invention. Preferably, the layer comprises a heat absorbing material as described above. Desirably, the layer of blocking composition is thick enough to allow the heated layer to "conform" to the surface of the lens blank.
The blocking composition of the present invention is preferably utilized in conjunction with a suitable lens blank coating or tape. Preferred tapes for use with the blocking composition have a pressure-sensitive adhesive surface and a tack-free adhesion promoting surface. The tapes assist in the firm bonding of the 2 o lens blank to the lens block (i.e., the p~e~ ; sensitive adhesive on the tape firmly bonds to the lens blank and the thermoplastic lens blocking composition firmly adheres to the tack-free backside of the tape when applied thereto in thewarm state and cooled). In addition, pl~r~ c;d tapes are conformable, that is, they follow the curvature of the lens blanks without any wrinkles or air bubbles; and2 5 translucent, that is, they permit light to pass therethrough. As a result, the lens may be visually aligned in the a~ pliate device prior to blocking. Still further, when pl~r~ d tapes of the present invention are removed from the lens they leave virtually no adhesive residue. Thus, messy and time con~l~ming cleaning operations need not be performed on the lens before it can be used.

Despite this clean removability, suitable tapes of the present invention exhibit excellent adhesion to both the lens blank and the thermoplastic blockingcomposition. Additionally, the tapes of the invention are able to withstand the shear forces encountered during the surfacing and edging operations. As a result, lenses are held in accurate position throughout these operations. An added benefit offered by the tape of the present invention is the protection provided to the lenses from thermal and mechanical shock.
The composition of the exposed surface of the tape (i.e., the non-adhesive surface away from the lens blank) should be selected so as to achieve the desired degree of adhesion with the particular thermoplastic blocking composition. The blocking compositions described herein generally comprise varying amounts of polar constituents or groups. While not intending to be bound by theory, it is presently believed that the polar constituents or groups present in certain blocking compositions of the present invention may interact with the polar groups present in certain tape backings and thus contribute to the adhesion between the tape surface and the thermoplastic cu~ osiLion (e.g., through a hydrogen bonding mechanism). According to this theory, the amount of available polar constituents or groups in both the blocking composition and at the surface of the tape would impact the total amount of adhesion between the 2 o composition and the tape.
For example, it has been discovered that blocking compositions comprising polycaprolactone polymers exhibit extremely high adhesion to certain con~ el.;ial lens protection tapes that have a backing surface layer made from a polyurethane polymer (a very polar backing). The level of adhesion is 2 5 often too high and causes difficulties when the user attempts to deblock the lens and block. In contrast, this same thermoplastic blocking composition adheres poorly to non-polar polymers such as polyethylene. The poor adhesion is undesirable as the lens and block may become detached during lens procçs~ing.

Surprisingly, a tape backing co~ ?lisillg a blend of a polar polymer and a "~ tin3~" polymer (e.g., a "non-polar" polymer) provides an ideal surface against which such a polycaprolactone blocking composition may be adhered.
The two component backing may be produced, for example, from these two dirr~ ,nL and often incompatible types of materials by coextrusion procçs~ing techniques. Alternatively, one may construct the backing from a suitable copolymer material that comprises both polar and non-polar or t1illltinp con~tih~nt~ or groups.
A wide variety of polymers may be employed as the "polar" polymer.
Pler~lled polymers colll~lishlg polar constituents or groups include polyule~halle polymers and polycaprolactone polymers. Particularly ~lerc;ll~d polyul~Lllalle polymers include "ESTANE" polyether type polyurethanes from the B.F. Goodrich Co., Cleveland, OH. Suitable ESTANE polyether type polyurethanes include grades 58370, 58866, 58202, 58300, 58891, 58630, 58309, 58311, 58315, 58863, 58887, and 58810. Polyester type polyurethanes may also be suitable. Examples of polyester type polyurethanes include ESTANE grades 58360, 58206, 58271, 58092, 58134, 58130, 58277, 58133, and 58137. Other suitable polyurethane polymers or polar group cont~inin~
polymers may be used if desired. For example, PELLETHANE, a polytetramethylene glycol ether thermoplastic polyurethane elastomer, from Dow Ch~mic~l Co. Suitable polycaprolactone polymers for use as the "polar"
polymer of the tape include the high molecular polycaprolactone polymers previously described as being L~l~r~ll.,d or suitable for the blocking composition. A particularly preferred polycaprolactone polymer for this use is CAPA 650.
A wide variety of polymers may be employed as the "diluting" polymer.
Pl~r~lled ~ ting polymers comprise non-polar constituents or groups and include, e.g., polyethylene polymers and copolymers. Also prer~lled are low density polyethylene polymers such as "AFFINITY" VLDPE and "ASPUN"

- W O 97/109Z4 PCT~US96/14668 LLDPE (an ethylene-octene copolymer) both from Dow Cht-rnir~l Co., Midland, MI. Suitable AFFINITY polymers include grade PL 1845. Suitable ASPUN resins include grades 6804, 6806, 6814, and 6809. Suitable diluting polymers include ENGAGE 8200 polyolefln elastomer from Dow Chl~mic~l Co.
Particularly ~lc;rcllcd "flihlting" polymers include "BYNEL" resins available from E.I. Du Pont de Nemours and Colllpally, Wilmington, DE including:
anhydride modified ethylene acrylate copolymers such as grades E369 and E374 (now commercially available as "Bynel 2174"); a maleic anhydride modified linear low density polyethylene (available as "Bynel 4109"); and a maleic anhydride modified low density polyethylene (available as "Bynel 4206").
The tape backing preferably comprises less than about 60 % polar component, and more preferably between 20 and 60 % (e.g., a preferred blend of polyurethane polymer with a non-polar polymer such as VLDPE comprises less than about 60 % polyulclhalle component, more preferably between 20 and 60 % polyulclhalle). As previously mentioned, the tape backing, C~lllpli~illg both polar and non-polar constituents or groups may be processed by coextrusion methods as herein described.
The tapes of the present invention may also include additional "core"
layers of materials (including layers of materials that do not comprise an olefin 2 o moiety and an acid moiety) bet~,veen the adhesion promoting surface layer and the ples~ule sensitive adhesive layer. Examples of useful materials for the optional core layers include: polyolefins, ethylene vinyl acetate copolymers;
ethylene methylacrylate copolymers; ethylene ethylacrylate copolymers; ethylene acrylic acid copolymers; vinyl polymers (e.g., polyvinyl chloride); urethane 2 5 polymers (e.g., polyester urethanes and polyether urethanes); polyester films (e.g., poly(ethylene terephth~l~te)); ionomer polymers; maleic anhydride/acrylicacid graft copolymers with ethylene vinyl acetate copolymer, ethyl acrylate, polyethylene, or polypropylene such as "BYNEL" resins from E. I. Du Pont de Nemours and Company; and polyamide films (e.g., nylon). The core layer should CA 0222980l l998-02-l7 - W O 97/10924 PCT~US96/14668 be selected so as to provide a tape with the desired conformability. In addition, the core layer should optimally provide a surface that retains the adhesive layer, i.e., inhibits adhesive transfer to the lens blank. Additional layers, such as "anchoring" layers or "tie" layers, may be used if desired, e.g., to join the backing to the adhesive layer.
The total thickness of the polymer backing (including any core or skin layers or coating applied thereto, but not including the adhesive layer of the tape) is preferably between about O.Ol and 0.25 mm, more preferably between about 0.03 and 0. l 5 mm, most preferably between 0.04 and 0. l rnm.
0 A wide variety of adhesives may be used when forming the tapes of the present invention. Most preferably, the adhesive is a pressure s~ ive adhesive. Suitable pressure-sensitive adhesives exhibit high bond strength to the ophth~lmic lens (e.g., plastic and glass). They also exhibit high cohesive strength and high bond strength to the backing layer. Preferably, they leave virtually noa&esive residue when removed from the lens.
The amount of adhesive present on the backing layer should be sufficient to hold the tape on the lens during the surfacing and generating process. It hasbeen found preferable that the amount of adhesive present be in the range of about 7 g/m2 to l 60 g/m2. More preferably, the amount of adhesive present is in2 o the range of about 15 g/m2 to l 00 g/m2; most preferably, the amount of adhesive present is in the range of about l 5 g/m2 to 80 g/m2; and optimally, it is in the range of about l g g/m2 to 80 g/m2.
A variety of pressure-sensitive adhesives are useful. They include polyacrylate adhesives, natural rubber adhesives, thermoplastic rubber adhesives, 2 5 and blend thereof. Preferably the adhesive is a polyacrylate adhesive.
In one presently preferred embodirnent, a layer of ~ e sensitive adhesive is coextruded with the backing to form the tape. Suitable "coextrudable" or "melt-processable" pressure sensitive adhesives include those adhesives disclosed in U.S. Patent Nos. 4,737,559 and 4,847,137, and in U.S.

- W O 97/10924 PCT~US96/14668 Patent Application Serial No. 08/390,780, which are herein incorporated by reference.
Examples of suitable melt-processable adhesives include crosslinked pressure-sensitive adhesives comprising a crosslinked copolymer comprised of A
monomers, PX monomers, and optional B monomers wherein:
A is a monomeric acrylate or methacrylate ester of a non-tertiary alcohol or a mixture of non-tertiary alcohols, said alcohols having from 1 to 14 carbon atoms with the average number of carbon atoms being about 4-12;
l o PX is a copolyrnerizable mono-ethylenically unsaturated aromatic ketone monomer free of ortho-aromatie hydroxyl groups; the copolymer being crosslinked by means of said PX monomer and the degree of cro.~linkin~ and the degree of polymeri7~1ion of the eopolymer being such that the crosslinked pressure-sensitive adhesive composition preferably has a creep compliance value (hereinafter J-value) of at least about 1.2 x 10-5 cm2/dyne; and B is an ethylenically unsaturated eompound eopolymerizable with the A
and/or PX monomers.
Use of the PX monomer to crosslink the copolymer allows for eontrol of 2 o the creep compliance of the adhesive. Copolymerizing the PX monomer into the baekbone of the ~ies~ule-sensitive adhesive copolymer also allows for cro~linkin~ of the copolymer with ultra-violet or aetinie radiation after formation of the eopolymer. Further, copolymerizing the PX monomer into the polymer baekbone before the ero~linking thereof greatly inereases the effieiency of the cro.~linkin~ obtainable by inclusion ofthe PX monomer in the adhesive as compared with addition of an aromatic ketone compound which is not initially copolymerized into the copolymer. Because of the increased efficiency, only small amounts of PX monomer are needed to achieve useful degrees of - cro~linkin~.

The number and composition of A, PX and B monomers and the degree of polymerization of the copolymer are preferably adjusted to obtain the desired physical properties of the adhesive (e.g., the desired degree of creep compliance).
For a polymer having a given A and B composition, an increase in the amount of PX monomer will generally result in an increase in the degree of photocro~linkinp and decrease the level of creep compliance of the copolymer.
Likewise, an increase in the degree of polymerization of the copolymer will decrease the level of creep compliance of the adhesive. Accordingly, as the amount of PX monomer is increased and, as a result, the degree of photocro~.clinkinp is increased, the degree of polymerization ofthe copolymer adhesive should be decreased to obtain a comparable level of creep compliance.
Conversely, if the amount of PX monomer is decreased, and, as a result, the degree of photocros~linkin~ is decreased, the degree of polymerization of the uncrosslinked copolymer adhesive should be increased to obtain a comparable level of creep compliance when crosslinked. For example, a pl~r~llcd composition of the copolymer adhesive is 94 parts isooctyl acrylate, 0.04 parts para-acryloxy bell~ophenone and 6 parts acrylic acid. For this particular composition, the inherent viscosity, which is a measure of the degree of polymerization of the res--ltin3~ copolymer before cro~linkin~ should be from 2 o about 1 to about 1.7 dl/g.
To obtain the desired physical properties, the weight of PX monomer is generally within the range of about 0.01% to about 2%, preferably about 0.025%
to about 0.5% of the total weight of all monomers in the copolymer.
In general, the inherent viscosity of the uncrosslinked copolymer should range from about 0.5 to about 2.0 dl/g, more preferably from about 0.8 to 1.6 toobtain the desired degree of polymerization of the copolymer. The test procedurefollowed and the apparatus that can be used to measure inherent viscosity are described in detail in "Textbook of Polymer Science", F. W. Billmeyer, Wiley-Interscience, Second Edition, 1971, pages 84 and 85.

- W O 97/10924 PCT~US96/14668 Monomer A is a monomer which contributes to the visco-elastic properties of the copolymer. Monomer A preferably is a monomeric acrylic or methacrylic acid ester of a non-tertiary alcohol or a mixture of non-tertiary alcohols, said alcohols having from 1 to 14 carbon atoms with the average number of carbon atoms being about 4 to 12. Examples of such monomers include the esters of acrylic acid or methacrylic acid with non-tertiary alkyl alcohols such as l-butanol, l-pentanol, 2-pentanol. 3-pentanol, 2-methyl-1-butanol, l-methyl-l-butanol, l-methyl-l-pentanol, 2-methyl-1-pentanol, 3-methyl-l-pentanol, 2-ethyl-1-butanol, 2-ethyl-1-hexanol, 3,5,5-trimethyl-1-o hexanol, 3-heptanol, 2-octanol, l-decanol, l -dodecanol, and the like. Such monomeric acrylic or methacrylic esters are known in the art and many are commercially available.
The PX monomer is a copolymerizable monoethylenically unsaturated aromatic ketone compound preferably free of ortho-aromatic hydroxyl groups, wherein only the ethylenically unsaturated group is copolymerizable with the A
monomers and optional B monomers under the polymerization conditions selected to form the copolymer.
Aromatic ketones free of ortho-aromatic hydroxyl groups absorb ultraviolet radiation to form a triplet excited state through intersystem crossing.
2 o These excited state molecules can abstract hydrogen radicals from the polymer.
The free radical sites thus generated on the polymer can combine to form crosslinks. The semi-pinacol radical which results from the combination of the photocrosslinker (PX) and the hydrogen radical can also lead to cro~linkinp since the photocrosslinker is copolymerized. The presence of a hydroxyl group as2 5 ring substituent in a position ortho to the carbonyl on the aromatic ring will inhibit the cro~linking ability of the aromatic ketone monomer. Accordingly, thearomatic-ketone monomer is preferably free of ortho-aromatic hydroxyl groups.

Preferred PX monomers are represented by the general formula:

R ~ C~) Y-Z

wherein R is lower alkyl or phenyl, provided that R may be substituted with one or more halogen atoms, alkoxy groups, or hydroxyl groups, and further provided that when R is phenyl substituted with one or more hydroxyl groups, any such hydroxyl groups must be meta or para to the aromatic carbonyl;
X is halogen, alkoxy, or hydroxyl, provided that when an X is a hydroxyl groups, X must be meta or para to the aromatic carbonyl;
nisanintegerfromOto4;
Y is a divalent linking group, preferably selected from the group con~i~tin~ of a covalent bond, an oxygen atom (-O-), an amino groups (-NR'-wherein R is hydrogen or lower aL~yl), an oxyalkyleneoxy group (-O-R"-O-wherein R" is an alkylene group), a carbamoylalkyleneoxy group (-O-R"-O-C(O)-N-(R')-R'"- wherein R'" is a covalent bond or an alkyleneoxy group such as -R"-O- wherein R" is an alkylene group); and Z is alkenyl or ethylenically unsaturated acyl.
Particularly ~,~fel,c~d PX monomers are the acryloxybenzophenones, e.g., para-acryloxybenzophenone .
2 o The optional B monomer is an ethylenically unsaturated compound copolymerizable with the monomeric acrylic acid ester and is employed to modify the physical properties of the copolymer. In general, the addition of the B
monomer will reduce the flexibility of the copolymer. Preferred B monomers are acrylic acid, methacrylic acid, itaconic acid, acrylamide, methacrylamide, 2 5 acrylonitrile, methacrylonitrile, vinyl acetate, and N-vinylpyrrolidone. The B
monomer may be included at levels up to 25% of the total weight of all monomers. The preferred adhesive according to the present invention will contain :; :
CA 0222980l l998-02-l7 - W O 97/10924 PCT~US96/14668 from about 1% to about 15% by weight of B monomer of the total weight of all monomers. In a preferred adhesive, the amount of acrylic acid or acrylamide willrange from about 1% to about 7% by weight of total monomer. In adhesives cont~inin~ N-vinylpyrrolidone as the B monomer, the preferred copolymer will contain from about 5% to about 15% of N-vinylpyrrolidone by weight.
The A monomer, PX monomer, and optional B monomer may be dissolved in a suitable inert organic solvent and polymerized by standard free radical polymerization l~tili7in3~ a suitable free radical initiator such as those described U.S. Patent No. RE 24,906(Ulrich). Suitable initiators which may be 0 utilized include azo compounds such as 2,2'-azo-bis(isobutyronitrile), hydroperoxides such as tert-butyl hydroperoxide, peroxides such as benzoyl peroxide or cyclohexanone peroxide. Generally, from about 0.01% to about 1%
by weight of thermally activatable initiator based upon the total polymerizable composition is used, preferably 0.01% to 0.5%.
The organic solvent utilized in the free radical polymerization may be any organic liquid which is a solvent for the reactants and product, that is inert to the re~ct~nt~ and product, and will not otherwise adversely affect the reaction.
Suitable solvents include ethyl acetate and mixtures such as ethyl acetate with toluene, heptane and toluene and isopropyl alcohol and heptane with toluene and 2 o methyl alcohol. Other solvent systems are useful. The amount of solvent is generally about 30-80% by weight based on the total weight of the reactants and solvent. Copolymerization may be carried out by other well known techniques such as suspension, emulsion or buLk polymerization.
The uncrosslinked copolymer is easily coated or coextruded upon suitable 2 5 b~ckin~ After the adhesive has been coated or coextruded, it may be subjected to ultraviolet radiation of sufficient intensity for a time sufficient to crosslink the copolymer to the desired degree by means of the aromatic ketone groups of the PX monomer. The degree of cro~linkin~ by means of the PX monomer is controlled by the amount of P~ monomer in the copolymer and the intensity of - W O 97/10924 PCT~US96/14668 the crosslinking radiation to which the uncrosslinked copolymer is exposed during the method of preparing an adhesive of this invention.
To measure the creep compliance ofthis adhesive, a 150-micrometer thickness of the adhesive is knife-coated onto a smooth film of polytetrafluoroethylene. The coated film is then dried to constant weight by placing it in an air-circulating oven generally for at least five minlltec at 110~C.
The adhesive, thus dried, is stripped from the polytetrafluoroethylene and two test pieces of equal area are die-cut and placed in a parallel plate creep compliancerheometer, one piece being on each side of the center plate, with an outer platecontacting the exposed surface of each. Screws which connect the two outer plates are then tightened so as to compress the interposed layers of adhesive approximately 10%. The parallel plates are placed in horizontal arrangement and one end of the center plate is connected to a chart recorder. A hook is attached to the opposite end of the center plate with a flexible wire extending horizontallyfrom the hook and then downward over a pulley, the outer plates being held in a fixed position. A suitable weight (one sufficient to measurably deform the sample a distance no greater than its thickness) is attached to the free end of the wire, then the strip chart recorder is started. The weight typically used to exert thestress on the adhesive films is S00 grams. From the strip chart recorder, the time 2 o and the displacement (strain) are read and the applied force (stress) is recorded.
The creep compliance at a given temperature is then calculated using the equation:
J(t, = 2AX/hf where t is the time at which the measurement is taken, A is the area of one face of 2 5 the adhesive samples, h is the thickness of the adhesive mass, X is thedisplacement at time t (where X is less than h) and f is the force due to the mass attached to the wire connected to the middle plate. Where A is expressed in cm2,h in cm, X in cm, and f in dynes, the compliance value J(t) is given in cm2/dyne.

It has been found that the adhesive films of this embodiment of the invention have the required degree of compliance and the short term creep to function as an exceptionally fine pressure sensitive adhesive when the J value measured at ambient conditions at the end of a 3 minute period of subjection to stress is at least about 1.2 x 10-5 cm2/dyne to about 2.3 x 10-5 cm2/dyne, preferably about 1.3 x 10-5 cm~/dyne to about 2.0 x 10-5 cm2/dyne.
In a second embodiment, the adhesive comprises a co-extrudable adhesive such as are disclosed in U.S. Patent Nos. 4,833,179 and 4,952,650, which are herein incorporated by reference. These suitable coextrudable adhesives may be made by the suspension polymerization of a pressure-sensitive acrylate copolymer bead having a glass transition temperature of 0~C or less. This methodcomprises the steps of:
(a) making a monomer premix comprising (i) an acrylic acid ester of a non-tertiary alcohol, said alcohol having from 1 to 14 carbon atoms, with the average nurnber of carbon atoms being about 4 to about 12, (ii) a polar monomer copolymerizable with said acrylic acid ester, (iii) a chain transfer agent, (iv) a free-radical initiator, and 2 o (v) a modifier moiety;
(b) combining the premix with a water phase cont~ining a suspending agent to form a suspension;
(c) concurrently ~git~ting the suspension and permitting polymerization of said monomer premix until polymer beads are forrned; and 2 5 (d) collecting the polymer beads, whereby the amount of the modifier moiety is sufficient to render wet copolymer beads non-agglomerating at room temperature to be safely handleable and transportable. The modified moiety is preferably selected from the group consisting of polystyryl macromers, reactive zinc salts and hydrophobic silica. Certain zinc salts and the hydrophobic silicamay be added after polymerization has begun, if desired.
Suitable aL~yl acrylate monomers useful in this embodiment of the present invention include monofunctional acrylate ester monomers. Included within this class of monomers are, for example, isooctyl acrylate, isononyl acrylate, 2-ethyl-hexyl acrylate, decyl acrylate, dodecyl acrylate, n-butyl acrylate and hexyl acrylate. Preferred monomers include isooctyl acrylate, isononyl acrylate, and butyl acrylate. Acrylate monomers preferably comprise at least about 80 parts based on 100 parts total monomer content, preferably from about 85 parts to lo about 95 parts.
Polar monomers useful in this embodiment of the invention include both moderately polar and strongly polar monomers. Strongly polar monomers useful herein include acrylic acid, methacrylic acid, itaconic acid, hydroxyalkyl acrylates, styrene sulfonic acid or the sodiurn salt thereof, maleic acid, fumaric acid, citraconic acid, acryl~rnicles7 and substituted acrylamides. Moderately polar monomers useful herein include N-vinyl lactams such as N-vinyl pyrrolidone, N-vinyl caprolactam, acrylonitrile, dimethyl amino-propyl methacrylate, and vinyl chloride. Preferred polar monomers include acrylic acid, methacrylic acid, acrylamides and substituted acrylamides. Polar monomers preferably comprise up 2 o to about 20 parts based on the total monomer content.
Modifier moieties useful in the method of the present invention include polystyryl methacrylate macromolecular monomers (macromers), zinc oxide or reactive zinc salts, and hydrophobic silica. Preferred moieties include the reactive zinc salts, and the macromers. A variety of useful macromers and methods for their preparation are disclosed in U.S. Patent No. 3,786,116, which is herein incorporated by reference. A particularly useful l-polystyrylethyl methacrylate macromonomer is commercially available under the name Chemlink 4500TM.
This macromer is a high glass transition temperature (Tg) polymeric material, having a Tg of about 90~C or higher, and a molecular weight of from about 5,000 to about 25,000. The modifier moiety is suitably present in an amount ranging from about 0.05 to about lO parts based on lO0 parts total monomer content. The preferred level of modifier moiety varies with the selection of the moiety, i.e., a preferred level of macromer ranges from 0.5 to about l 0 parts based on l 00 parts monomer content. The macromer is added to the monomer premix. The reactive zinc salts and/or hydrophobic silica may be added to the monomer premix, alternatively, they may be added to the suspension during polymerization.
The copolymer beads of this embodiment are prepared by an aqueous suspension polymerization technique ntili7in~ conventional suspension agents with optional anionic surfactants. The amount of surfactant is preferably from about 2.5 ppm to about l.0 part based on lO0 parts total monomer content.
Preferred surfactants include sodium lauryl sulfate and sodium dioctyl sulfosuccinate. Non-ionic surfactants may also be included so long as an anionicsurfactant is present and predominates.
Suspending agents are those conventionally used in suspension polymeri7~tion processes. They may be minim~lly water-soluble inorganic salts such as tribasic calcium phosphate, calcium carbonate, calcium sulfate, barium sulfate, barium phosphate, hydrophilic silicas, and m~pne~ium carbonate.
Preferred inorganic suspending agents include barium sulfate, hydrophilic silicas, 2 0 and tribasic calcium phosphate. Water-soluble organic suspending agents may also be used, e.g., polyvinyl alcohol, poly-N-vinyl pyrrolidone, polyacrylic acid, polyacrylamide and hydroxyalkyl cellulose. The suspending agent is present in amounts ranging from about O.Ol part to about 5 parts based on lO0 parts total monomer content.
2 5 Initiators for polymerizing the monomers to provide the copolymer beads of the invention are those which are normally suitable for free-radical polymerization of acrylate monomers and which are oil-soluble and have low solubility in water, e.g., organic peroxides such as benzoyl peroxide, lauryl peroxide and various thermal initiators. Preferred thermal initiators include 2,2'-- W O 97/10924 PCTnJS96/14668 azobisbutryronitrile, commercially available from E. I. duPont de Nemours under the trade name VAZO 64. The initiator is present in an amount from about 0.05 toabout 1 part based on 100 parts total monomer content.
Useful chain transfer agents include melca~ s, alcohols, and carbon tetrabromide. Isooctyl thioglycolate and carbon tetrabromide are preferred. The chain transfer agent is present in any amount of from about 0.01 to about 0.5 part based on 100 parts total monomer content.
Photocro~linkin~ agents may also be used in methods of the invention.
Preferred cro~1inking agents include copolymerizable aromatic ketone monomers, especially acryloxybenzophenone. When present, the photocro~linker generally comprises from about 0.01 to about 5.0 parts based on 100 parts total monomer weight.
The monomers, modifier moiety, chain transfer agent, free-radical initiator, and any optional m~t~ ri~1~ are mixed together in the prescribed ratio to form a monomer premix. They are then combined with a water phase comprising a suspending agent, any optional surfactant and water, and are polymerized with agitation for from about 2 to about 16 hours at a temperature of from about 40~Cto about 90~C to give a suspension which contains the copolymer beads. The beads are then washed and separated from the water by means such as gravity filtration. The filtered product also generally comprises about 15-30% water.
In yet a further embodiment, the adhesive layer alternatively may be coated onto the backing (e.g., using a conventional coating process) or transferred onto the backing (e.g., in the form of a transfer adhesive or a double-sided adhesive tape). Suitable transfer adhesives include 3M Transfer Adhesive No.
2 5 1524 from 3M, St. Paul, MN or the like.
Suitable coatable pressure sensitive adhesives include adhesives that comprise a polymer of an acrylate ester of acrylic acid with a non-tertiary alcohol.
These adhesives also preferably contain a minor amount of a copolymerized acid or amide. These adhesives and methods of their preparation are described in U.S.

- W O 97/10924 PCT~US96/14668 Patent No. RE 24,906 which is herein incorporated by reference. An example of a useful pressure-sensitive adhesive of this type comprises a polymer of 90 parts by weight isooctyl acrylate and l 0 parts by weight acrylic acid available as Y 9460 from 3M Company.
Also useful are natural rubber adhesives comprising natural rubber and, preferably, a tackifying resin. One such adhesive comprises natural pale crepe rubber (l00 parts by weight), polyterpene resin (75 parts by weight), and antioxidant (l part by weight). Other useful natural rubber adhesives are also useful and will be apparent to those skilled in the art.
0 In addition, thermoplastic rubbery adhesives comprising a rubbery block copolymer and, preferably, at least one resin compatible with the block copolymer are useful. The rubbery copolymers have the general configuration A-B-A wherein the A units represent a thermoplastic polymer block with a Tg above 20~C and the B units represent an elastomeric polymer block formed from a conjugated diene. The A units are relatively incompatible with the B units andhave an average molecular weight of from about 5,000 to l 25,000. Preferably theA units are styrene and the B units are polybutadiene or polyisoprene or poly(ethylene/butylene). An example of block copolymer of this type is Shell Chemical Company Kraton D l l 0 l . Other block copolymers of this type may also2 o be used. Resins compatible with the block copolymer are known and include, for example, hydrocarbon resins, coumarone-indene resins, dimerized rosins, metal resin~tes7 hydrogenated rosins, poly-terpene resins and heat treated wood rosins.
The polymer backing of the present invention may contain a variety of additional ingredients. Thus, they may be modified by the incorporation of agents 2 5 that increase flexibility and/or clarity (e.g., nucleating agents), fillers, antiblocking agents, and the like. Fillers and antiblocking agents are useful inreducing blocking to other surfaces. Materials useful as fillers and antiblocking agents are well known in the art. If desired, low adhesion ba~k~ s (LAB) may be used as an antiblocking agent. However, the selection of the LAB should be made so as to not i~ lr~l~ with the desired level of a&esion between the tape backing and the blocking composition. Presently preferred tapes do not contain aLAB.
Other layers and ingredients may be employed in the tapes of the present invention. For example, an anchoring layer may be employed between the backing layer and the pressure-sensitive adhesive in order to improve the bond therebetween. The anchoring layer can be selected from a variety of m:~t commonly employed for improving bonds between substrates.
It has been found that colorants (e.g., dyes and pigments) are useful in the 0 tapes of the present invention to enhance the visibility of the tapes once they have been applied to the ophth~lmic lens blanks. Preferably they do not render the tapes opaque. Typically, they are included in the backing layer. They may also be included within the pressure-sensitive adhesive. Typically they comprise up to about l 0% by weight of whatever layer they are in. The colorants are preferablypigment~ A particularly useful pigment and concentration is copper phthalocyanine present in an amount in the range of 2 to 7 parts by weight.
The tapes of the present invention may be readily prepared from known processing techniques. Thus, for example, the pressure-sensitive a&esive may be applied by solution coating the ~plopl;ate adhesive onto the backing layer 2 o followed by removal of the solvent therefrom. Alternatively, the adhesive may be applied by first solution coating it onto a liner followed by removal of the solvent therefrom. The dried adhesive may then be nip l~min~t(?~l to the backing layer.
Alternatively, and presently preferably, the tape of the present invention may be prepared by coextruding an adhesive material and a separate polymeric 2 5 backing material or blend of backing materials. For example, the multilayered, coextruded tape may be made using multi-layered coextrusion feedblocks such as those fabricated by The Cloeron Co., Orange, TX. In one embodiment, a layer of backing material is coextruded with a layer of adhesive to form a two-layer tape.
The backing material and adhesive are individually melted and fed using a screw - W O 97/10924 PCTrUS96/14668 extruder into a coextrusion feedblock where the melt streams were combined. In another embodiment, a core layer and a skin layer or skin layers are coextruded with an adhesive layer using a multilayered coextrusion feedblock.
The method in which the polymer blend is prepared is not particularly critical within the preferred range of proportions and with the inclusion of thepreferred ingredients. Any conventional mixing device which provides substantialhomogeneity can be employed. Another possible method is to prepare the blend in a twin-screw mixing extruder at the desired proportions. It is also possible to prepare a polymer "master-batch" concentrate and then add the a~plol,liate 0 quantity of either virgin resin to obtain the desired proportions. It is also ~pl~pl;ate to incorporate other polymer additives, e.g., plasticizers, colorants, fillers, processing aids, antiblocks, stabilizers, etc. in the concentrate to enhance their dispersibility in the final blend.
Films of the blends of this invention are readily prepared by intim~t~ly admixing the polymers; and extruding the resulting mixture in the form of a clear, flexible sheet or film which is subsequently cooled in a draw-down procedure to form a backing film having an average thickness in the range of about 0.0 l mm to about 0.25 mrn or more, more preferably in the range of about 0.03 mm to about 0. l 5 mm, and most preferably in the range of about 0.04 mm to about 0. l O mm.2 o The thin sheet is extruded and drawn onto a chill roll.
Mixing of the required components is readily carried out in a conventional mixing app~dL~Is such as a Banbury mixer or screw-type extruder. In one embodiment wherein the mixing device is a screw-type extruder, the m~teri~l~ arefed into the barrel of the extruder. The extruded mixture may be mixed with 2 5 additional polymer(s) prior to final extrusion or may be fed directly into an extruder equipped with a sheet die, annular die, or coextrusion die and extrudedin the form of a transparent sheet onto a chill roll and drawn down to form a film having the desired thickness. Suitable extrusion apparatus include a typical screw-type extruder, an extruder equipped with a r~mmin~ device and the like.

W O 97/10924 PCT~US96/14668 In a preferred embodiment the mixing and extruding steps are carried out in a single apparatus which is a typical screw-type extruder that is equipped with a sheet die or annular die and feed means placed along the extruder barrel whichhouses the screw or screws of the extruder. The blend materials are introduced as the polymer is being extruded at a rate such that a constant mixture is m~int~ined.
Similarly, concentrated master-batches can be added to virgin material in the screw-type extruder.
The tapes of the present invention are easily applied to ophth~lmic lens blanks. Generally, the pressure-sensitive adhesive portion of the tapes of the l o present invention are applied to the front, or finished, surface of a lens blank. This may be done either by hand or, preferably, by means of a mechanical device. In either event, the tape of the present invention conforms readily to the configuration of the lens blank without wrinkles, folds, air bubbles, or other discontinuities between the adhesive and the front surface of the lens. Preferably, the tape of the invention is applied so that it covers the entire front surface or back surface of the lens. Normally it is applied to the front surface.
The tapes of the invention may be used on both plastic and glass lens blanks which may vary in curvature from plano to 1 O-base curve or higher. It is, of course, understood that the particular tape employed may be selected to suit 2 o the particular lens to be altered. Preferably, more conformable tapes are employed with lens blanks having a higher base curvature.
After application, excess tape is trimmed away from the periphery of the lens blank. The lens blank is then blocked. After the blocking composition has solidified and cooled, the blocked lens is removed from the blocking m~chine and2 5 is ready for mounting in the surfacing and/or edging machines. When these operations have been completed, the finished lens is deblocked, for example, by means of a sharp tap. This may be easily accomplished, for example, with the aidof a hollow cylinder that is adapted to support the finished lens on its wall while receiving the still attached lens blank within its hollow portion. By holding the .-53-lens and cylinder together and striking the bottom of the cylinder upon a hard surface, the bond between the blocking composition and the tape may be broken.
The lenses may also be deblocked, for example, by melting the blocking composition in hot water. In either event, the tape is then removed from the lens and discarded. The lens and block may then, if necessary, be cleaned.
The blocking composition of the present invention is preferably utilized in conjunction with a suitable preformed base block. Preferred base blocks are .ocign~l so that the blocking composition and base block form a unitary structure that securely holds the lens during processing. More preferably, the base block and composition are easily separated after use so that the base blockand/or the composition may be reused or recycled.
A presently preferred base block contains a rear portion that is sized and adapted to fit the chuck of a desired lens processing m~chin~ and a front portion that is adapted to retain a blocking composition. The exact size and shape of the rear portion of the preformed base block may assume a variety of configurations. The ~l~r~ d preformed base block also has a "negatively"
tapered peripheral edge and a curved front surface. The tapered peripheral edge is preferably angled so as to provide a mechanical "overcut" and retain the thermoplastic blocking composition against the preformed base block. This 2 0 avoids the need for adhesive intern~ the thermoplastic blocking composition and the preformed base block. The blocking composition may be very easily and cleanly separated from the preforrned base block by simply holding t'ne preformed base and "peeling" the blocking composition off the base. Upon separation, very little if any blocking composition remains stuck to the preformed base. There is also no need to "dig" out blocking composition from cavities formed by "positively" tapered "undercuts". If desired, the cleanly separated preformed base block may then be reused, and the blocking composition recycled (i.e., reheated) and used again.

- W O 97/10924 PCTrUS96/14668 To ~l~V~ undesired rotation of the thermoplastic blocking composition relative to the preformed base block the preformed base block preferably also comprises a means to resist such rotation. This may be accomplished using an adhesive or a m~rh~nic~l means. Suitable mechanical means include, for example, lun~ (e.g., off-centered fill holes) that extends at least partially through the ~lerolllled base block. Blocking composition that solidifies in the runner will help prevent such rotation. Alternatively, for example, the preformed base block may optionally comprise a non-circular periphery, such as a scalloped outer edge as shown in FIG. 9e or a key or plurality of keys as 0 shown in FIG. 10e. Other mechanical means to resist rotation may be employed, if desired.

Detailed Description of the Dr~wil.gs Shown in FIG. 1 is an ophth~lmic lens blank 10 and a conventional lens base block 20. A tape 12 or other lens coating is shown applied to the semi-fini~hl-d surface of the lens and provides additional protection to keep the lens from being scratched or otherwise ~l~m~ged by the heat of the lens blocking composition when the molten blocking composition is placed '~adjacent" to the lens blank and/or to achieve better adherence between the base block and the 2 o lens blank. When base block 20 is placed against lens 10 a cavity is formed between cavity 21 of the block and the surface of the lens. A lens blocking composition may be injected through hole 22 to fill the cavity.
FIG. 2 depicts a side view of the ophth~lmic lens blank 10 and lens base block 20 of FIG. 1. As shown in FIG. 2, an optional tape 12 or other lens coating may be applied to the semi-fini~h~l surface of the lens. A lens blockingcomposition 14 then fills the cavity forrned between metal base block 20 and optional tape 12 on lens 10 and attaches the base block to the lens. Depending on the particular composition used, the composition may just fill the cavity or may form a film between the base block and the lens (as shown). FIG. 3 depicts - W O 97/10924 PCT~US96/14668 an end view of the ophth~lmic lens blank and lens block of FIG. 2. Base block 20 is provided with positioning guides 24 and hole 22 through which lens blocking composition 14 may be injected.
FIGS. 4a and 4b depict an alternative embodiment of the present invention wherein a lens block 16 is formed from the lens blocking composition of the present invention. If desired, a tape 12 or other lens coating may be first applied to the semi-fni~hPcl surface of the lens. As shown in FIG. 4c, a mold 30 is used to define a cavity in the shape of a lens block. The mold 30 forms the cavity using the fini~h~-l surface of lens 10 as one boundary. When a lens 0 blocking composition is injected into the mold (e.g., through gate 26) and allowed to harden a rigid block is formed against and adhered to the lens or lens coating.
FIGS. 5a and Sb depict an alternative embodiment of the present invention wherein a lens block 16 is formed from the lens blocking composition of the present invention. If desired, a tape 12 or other lens coating may be first applied to the semi-finished surface of the lens 10. In this embo~lim~nt, lens block 16 comprises positioning guides 17 and hole 15.
FIGS. 6a and 6b depict a further alternative embodiment of the present invention wherein a lens block 16 is formed in part from the lens blocking composition of the present invention. In this embodiment, a ~lerclllled metal (or other rigid material) base block 25 is placed in the blocker, and the lens blocking composition is used to fill a cavity between the preformed base block and the lens 10 and to form a support ring of blocking composition against the lens. Preformed base block 25 may comprise one or more positioning guides 17, one or more polishing pin guide holes 24, and preferably contains an optional means to hold or "lock" the pl~rolllled base block against the blocker while the cavity is being filled with the blocking composition. One method for accomplishing this is to provide one or more "J-locks" 19, which engage pins on the blocker or on an optional cooling ring. The "J-locks" prevent the - W O 97/10924 PCT~US96/14668 prerolll,ed base block from being pushed away from the blocker by the blocking composition. This ensured that the positioning guides of the plefo~ ed base will be in the desired ~ nm~ont. Preformed base block 25 preferably contains a one or more holes 29 through its rear surface. When the base block and blocking composition are formed to provide a lens block, the blocking composition is viewable through the rear holes 29. After the block is separated from the lens, the user may conveniently separate the ~ r~ln,ed base block from the blocking composition by holding the base block and pressing against the blocking composition (e.g., using a thumb or a tool) through the rear hole 0 29.
FIGS. 7a and 7b depict a further alternative embodiment of the present invention wherein a lens block 23 is formed in part from the lens blocking composition of the present invention. In this embodiment, a pler~lllled metal (or other rigid material) base block 25 is placed in the blocker, and the lens blocking composition is used to fill the cavity between the preformed base blockand the lens and to form a support ring of blocking composition against the lens. Preformed base block 25 may comprise one or more positioning guides 17, one or more polishing pin guide holes 24, and optionally contains a means to hold or "lock" the preformed base block against the blocker while the cavity 2 o is being filled with the blocking composition. Preformed base block 25 preferably contains a one or more holes 22 through its rear surface. When the base block and blocking composition are formed to provide a lens block, the blocking composition is viewable through the rear holes 22. After the block is separated from the lens, the user may conveniently separate the preformed base block from the blocking composition by holding the base block and pressing against the blocking composition (e.g., using a tool) through the rear surface hole 22.
Shown in FIG. 8a is an ophth~lmic lens blank 10 and a lens block 40 of the present invention. The lens block 40 comprises a preformed base block 42 and a thermoplastic blocking composition 44. An optional tape 12 or other lens coating is shown applied to the semi-fini~hPd surface of the lens 10 and provides additional protection to keep the lens 10 from being scratched or otherwise damaged by the heat of the lens blocking composition 44 when the molten blocking composition is placed "adjacent" to the lens blank and/or to achieve better adherence between the block and the lens blank. As shown in FIGS. 8b to 8d, preformed base block 42 is inserted into a mold 46 that is placed adjacent the lens blank 10. This forms a cavity between and optionally around at least a portion of the preformed base block 42 and the surface of the lo lens. The mold may also be fitted with a cooling apparatus, such as a water circuit 48 that allows the circulation of chilled water to pass. The thermoplastic blocking composition is then injected into the cavity between the p.,efo,.lled base block 42 and lens 10 and allowed to harden. The thermoplastic blocking composition 44 may be injected either through a hole 50 in the mold that is located opposite the lens (as shown in FIG. 8b and 8c) or through a hole 51 in the mold that is located on the side of the block 40 as is shown in FIG. 8d.
FIG. 8b depicts a side view of the ophth~lmic lens blank 10 and lens block 40 of FIG. 1. As shown in FIG. 8b, an optional tape 12 or other lens coating may be applied to the semi-fini~h~-l surface of the lens. A lens blocking 2 o composition 44 then fills the cavity formed between the mold 46, preformed base block 42, and lens 10; and attaches the preformed base block to the lens.
FIG. 8c depicts a cross-sectional side view of the block 40 of FIGS. 8a and 8b.
Preformed base block 42 is shown in FIG. 8f having a rear surface 54 and collar 55 that together are sized and adapted to fit the chuck of a desired lens2 5 processing machine. As such, the exact s'7e and shape of this portion of the plero~ ed base block may assume a variety of configurations. Preformed base block 42 preferably also has a "negatively" tapered edge 56 and a curved front surface 58. A fill hole 122 may optionally be provided through the preformed base block 42 to enable filling from the rear surface. Tapered edge 56 is - W O 97/10924 PCT~US96/14668 preferably angled so as to provide a mechanical "overcut" and retain the thermoplastic blocking composition against the preformed base block 42. This avoids the need for adhesive between the thermoplastic blocking composition 44 and the ~Lefo""ed base block 42. The blocking composition may be very easily and cleanly separated from the preformed base block by simply holding the efolllled base and "peeling" the blocking composition off the base. It has been observed that having a peripheral overcut retention means is ~l~fell~d.
Upon separation, very little if any blocking composition remains stuck to the .lled base. There is also no need to "dig" out blocking composition from o cavities formed by "positively" tapered undercuts. If desired, the cleanly separated performed base block may then be reused, and the blocking composition recycled (i.e., reheated) and used again. To prevent undesired rotation of the thermoplastic blocking composition 44 relative to the preformed base block 42 the preformed base block 42 preferably also comprises a means to resist such rotation. This may be accomplished using an adhesive or a mech~nir~l means. For example, when the thermoplastic blocking composition is filled through an off-centered hole 122 that extends at least partially through the preformed base block, the material that solidifies in the hole will help prevent such rotation. Alternatively, for example, the preformed base block 2 o may optionally comprise a scalloped outer edge 132 as shown in FIG. 9e or a key 140 or plurality of keys as shown in FIG. 10e. Other mech~nir~l means to resist rotation may be employed, if desired.
FIGS. 8e to 8g illustrate the preformed base block of FIGS. 8a to 8c.
FIG. 8e is a rear end view of preformed base block 42, showing positioning guides 117, polishing pin holes 124, fill hole 122, and outer edge 130. FIG. 8f is a side view of this same L~lerolllled base block 42, illustrating rear surface 54, collar 55, and tapered edge 56. FIG. 8g is a front end view of preformed base block 42, illustrating fill hole 122 and curved front surface 58. If desired, e.g., for preformed base blocks that are formed from a plastic material, the polishing - W O 97/10924 PCT~US96/14668 _59_ pin guides optionally may be formed using a suitable insert, such as a metal or ceramic insert. The metal or ceramic inserts may resist wear that would coll~ ise the polishing process.
FIGS. 9e to 9g illustrate an alternative embodiment of the plero~ ed base block of FIGS. 8a to 8c. FIG. 9e is a rear end view of a plerolllled base bl~k, sh~wing posi.t.~oniE~.g guides 117, po!ishing pin holes 124, ..nd fi!l ho!e 122. The outer edge 132 in this example is scalloped so as to ~l~v~lll rotation of the thermoplastic blocking composition about the preformed base block. FIG. 9f is a side view of this same preformed base block, illustrating rear surface 54, 0 collar 55, and tapered edge 56. FIG. 9g is a front end view of this preformed base block, illustrating fill hole 122 and curved front surface 58.
FIGS. 10e to 10g illustrate a further alternative embodiment of the preformed base block of FIGS. 8a to 8c. FIG. 10e is a rear end view of a preformed base block, showing positioning guides 117, polishing pin holes 124, and fill hole 122. The outer edge 130 in this example contains at least one key 140 that helps prevent rotation of the thermoplastic blocking composition about the preformed base block. FIG. 10f is a side view of this same pl~rolnled base block, illustrating rear surface 54, collar 55, and tapered edge 56. FIG. 10g is a front end view of this LJI~rolllled base block, illustrating fill hole 122 and 2 o curved front surface 58.

The following examples are offered to aid in the underst~n~iin~ of the present invention and are not to be construed as limiting the scope thereof.
Unless otherwise innit~tt~ all parts and percentages are by weight.

EXAMPLES
Example 1 Polyetherester block copolymers were synthesized by placing the re~ct~nt~ in the amounts listed in Table l a into a 500 ml three-neck round bottom flask. The center neck had a stir shaft and paddle, one side neck had an adapterattached to a nitrogen source, and another side neck had a modified /Dean-Stark trap to condense and collect vapor. Run conditions for Runs 1-8 are given in Table lb. The heat source was a Wood's metal bath commercially available from Aldrich Chemical Company, Milwaukee, WI. The mixture was stirred with a nit~ogen flow until it cooled to approximately 150 ~C and then it was poured from the flask into a container.
Table la Run Reactants Numbe~
Diacid ShortChain Diol Polyol Name Amount Name AmountName Amount , r ~ g~
.cu,-c r ic ~ n" ~, --ER---- ~ETM~ 29~
r, -, _ '. . , nc n~ TM ' I (' r, c. - m~, ~ A ~ TM
er ~ u ~ TM ' i i Cil , , _,~ " , , ~ -- _A~ TM
. Icr - ac ~ . . . ,~ ~ ~ - TM
u er ac ' .. ,~-r ~ TM
ccin: aci~ . e- o ~ ~ TM
TERETHANE is the tradename for polyether giycols available from E. 1. Du Pont de Nemours, Inc., Wilmington, DE.

Table Ib Run Condittons Time Chours~TGIII~ alUIG ~~C)Nit~ogen Flow Rate (m~min) 7 (Shut down) 150 500 -The polyetherester materials, Runs 1-3 and 5-8, and a competitive m~t~ri~l, Comp. Run 9, commercially available as "FREE BONDTM Non-alloy Blocking Substance" from Gerber Optical Inc., South Windsor, CT were evaluated by Thermal Mech~nic~l Analysis (TMA) using a "Perkin-Elmer 7 Series Thermal Analysis System" commercially available from The Perkin-Elmer Corporation, Norwalk, CT to determine the percent change in dimensions while heating over a temperature range of 0 ~C to near the melting temperature at a rate of 5 ~C per minute. An expansion probe with 50 mN of applied force was used.
Transition t~ lp~ldLules and melting points were extrapolated at onset from the curves. The results for the polyetherester materials, Runs 1-3 and 5-8, and the competitive material, Comp. Run 9, are shown in Table 1 c.
Table Ic Thr~mnm~çh~ni~i An Iysis of Polyetheresters Run NumberPcrcent Changc in E~ Onset of D;.. ~ for a T~ làtu~G RangcTransition Melting (%~ T~ ,Ialu~ T~ a~ulG
(~C~ (~C) 1.6 39,55 64 f0 ~~ 60 ~C) 2 2.8 32,19,19,20 57 (O ~~ 52 q~) 3 1.7 40,38,39 62 ~0 ~~ 60 ~C
1.5 26 48 (O ~~ 45 ~C) 6 2.2 29,17,17 47 (O ~~ 45 ~C) 7 1.7 34736,37 50 (O ~~ 49 qC) 8 1.5 34734734 60 (O ~~ 58 ~C) Comp.Run9 2 9 29,25726 44 (O ~~ 41 ~C) WO97/10924 PCT~US96/14668 The polyetherester materials, Runs 1-3 and 5-8 had higher melting telnl~el~Lul~s and a lower percent change in dimensions over the temperature range of heating than the competitive rn~t~ri~l in Comp. Run 9.
The polyetherester materials, Runs 1- 8, were evaluated by Gel Permeation Chromatography (GPC) for weight, number, and z average molecular weights. GPC analysis was done in tetrahydrofuran ( I'HF) at 1.0 ml/min. using aHP109OLC System from Hewlett-Packard, Palo Alto, CA including a HP 1047A
Refractive Index detector and a HP Diode Array Detector (Wdetector at 254 nm). A CRI Permagel 10 micron particle size column from Column Resolutions Inc., San Jose, CA was used for high molecular weight materials. Analog signals were converted to digital data using Polymer Laboratories, Inc., Amherst, MA, software and hardware. Calibration was based on polystyrene standards from Pressure Chemical Co., Pittsburgh, PA. The sample solution was weighed accurately to give 15 mg of resin /5 ml solvent and filtered with a 0.2 micron "TEFLONTM Filter" from Scientific Resources, Eatontown, NJ and 100 microliters was injected into the column. A Polydispersity Index was calculated by dividing Mw by Mn. The results are shown in Table ld.

Table ld RunWeight AverageNumber Ave3~ageZ Average Polydi~ ily ~ex NumberMolecular Weight Molecular Molecular (M~ n?
(Mw~ Weight ~n? Weight (Mz?
23684 9871 38973 2.40 - 2 21411 10554 34580 2.03 3 15015 7253 24074 2.07 4 21488 8r82 35976 2.48 S 1640' 4 16 28342 3.41 6 21061 11 26 31237 1.78 7 1811~ 9199 28880 1.97 8 15448 7973 23949 1.94 2 o Number average molecular weight equals weight average molecular weight for a monodisperse system. Polydispersity Index is a measure of the CA 0222980l l998-02-l7 breadth of the polymer molecular weight distribution. Run 5 had the broadest molecular weight distribution.
The flow behavior of polyetherester formulations was e~mined using a parallel plate fixture on a Rheometrics Dynamic Analyzer (RDA-II) from Rheometrics, Inc., Piscataway, NJ. The steady shear viscosity (Pa s) was measured at shear rates of l, 5, and l 0 second~~ at 65.6 ~C. At each shear rate, the measurement was made when the torque was at steady state. The results are shown in Table l e.
Table le Run Number Shear Viscosity at Shear Rates of 1, 5, and 10 second i ~Pa s3 ls' 5s' lOs' 15.27 15.11 15.16 2 7.45 7.44 7.39 3 3.16 3.04 3.02 5.22 5.16 5.17 6 9.93 9.59 9.67 7 5.37 5.36 5.37 8 3.44 3.83 3.86 Comp. Run 9 0.98 0.91 0.88 The differences in the measured viscosity indicated variation in the molecular weight of the resin systems. For the "FREE BONDTM Non-alloy Blocking substance" (Comp. Run 9), the measured viscosity was at the limit of the instrument sensitivity; therefore, the viscosity may be approximate values.
The polyetherester materials, Runs 1-3 and 5-8, and the competitive material, Comp. Run 9, were evaluated for hardness using ASTM Test Method D2240-91 "Shore Type 'A' Hardness". Three measurements were made for each run. The results are shown in Table l f.

- W O 97/10924 PCT~US96/14668 Table I f Shore Type 'A' Hardness Test (A~TM D2240 - 91) Run Nu~nber M~
2 3 Average Comp. Run 9 66 63 64 64 Example 2 Polycaprolactone materials commercially available as "TONETM p 300~
(10,000 molecular weight) polycaprolactone from Union Carbide Chemicals and Plastics Company Inc., Danbury, CT, Run 1, and as "CAPATM 630" (30,000 molecular weight) polycaprolactone from Solvay Interox, Houston, TX, Run 2, were evaluated by Thermal Mechanical Analysis (TMA) using the sarne procedure described for Example 1. The results are shown in Table 2a along with the results of two comparison runs.

Table 2a Th~ u~ 1 Analy~is oi Polyo~ c., Run Ntlmber Percent Change in E~L~UI : Onset of D;.. ~ oo~for a Transition ~elt T,~ LUI~ RangeT~ lul~j Tc~ tu-~
(~C ) (~C ) 1.0 41, 47 61 (0~~ 54~C) 2 1.4 26.38, 41 60 (0~~ S4~C) Comp. Run 31 1.9 46 (0~~ 40~C) Comp. Run 4 ~2.9 29, 25, 26 44 (0~~ 41~C~
"OPTEKr~ Feather Lite Blocking Compound" available from Associated D~ Corporation, Optek Division, Pincllas Park, FL.
~'FREE BONDr~ Non-alloy Blocking Substance" available from Gerber Optical Inc., South Windsor, CT.

- W O 97/10924 PCT~US96/14668 The polycaprolactone materials, Runs l and 2, had a higher melt temperature and a lower percent change in dimensions over a t~n~eldLul~ range of heating than the competitive materials in Comp. Runs 3 and 4.
The polycaprolactone materials and the two comparison materials were evaluated by Gel Permeation Chromatography (GPC) for weight, number, and z average molecular weights using the same procedure described for Example l.
The results are shown in Table 2b.

Table 2b Run NumberWeight AverageNumber AverageZ AverageP~ly~ i Molecula~Molecular Weight Molecular Index Weight (M") Weight ~M~
~w) ~Mz) la 23850 5220 38803 4.57 Ib' 23520 4720 38611 4.98 2 61800 40190 87281 1.54 Comp. Run 3 35470 2500 179460 14.18 Comp. Run 4 26570 1140 172450 23.35 Run Ib differed from Run I a in that this sarnple was aged in an oven at 66 ~C for 30 days before GPC testing.

The polydispersity index shows that the competitive blocking compounds, Comp. Runs 3 and 4 had very broad molecular weight distributions. The "TONETM P-300 Polycaprolactone" from Union Carbide Chemicals and Plastics Company Inc., Runs l a and l b had a somewhat broader molecular weight distribution than "CAPATM 630 Polycaprolactone" from Solvay Interox, Run 2.
The flow behavior of polycaprolactone materials, Runs l and 2, and the two comparison materials, Comp. Runs 3 and 4, were examined using the same procedure described for Example l. The results are shown in Table 2c.

W O 97/10924 PCTrUS96/14668 Table2c Run Number Shear Viscosity at Shear Rates of 1, 5, and 10 s ' (Pa s) lsl 5s lOs 1 15.5 15.6 15.7 2 407.3 408.9 410.0 Comp. Run 3 2.6 2.4 2.21 Comp. Run 4 0.98 0.91 0.88 The polycaprolactone materials, Runs 1 and 2, had a higher viscosity than the competitive m~tt-rizll~ in Comp. Runs 3 and 4. The polycaprolactone in Run 2had a significantly higher viscosity than any of the other m~t~ri~l.s The tangent modulus of elasticity in bending and flexural strength were measured for the two polycaprolactones and the competitive materials using ASTM D 790-86, '~Standard Test Methods for Flexural Properties of Unreinforced and Reinforced Plastics and Electrical Insulating Materials" Test Method I. This test employs a three-point loading system ~ltili7ing center loading o on a simply supported beam. The specimen were molded by heating the material to its melting temperature and pouring into a fluorocarbon coated mold die to give a test specimen that was 165 mm long, 12 mm wide, and 6 mm thick. The measurements were made on a "MTS SinTechTM Mechanical Tester" from MTS
Systems Corporation, Eden Prairie, MN. The span tested was 96 rnm long giving a span to depth ratio equal to 16:1. The crosshead motion was 2 mm per min.
Four specimen were tested for each Run. The results are shown in Tables 2d and 2e.

Table 2d Run NumberTangent ~vlodulus of Elasticity in Bending (ASTM D 790 - 8~) ~MPa) 2 3 4 MeanStandard Deviation Comp. Run 3 28 48 32 11 30 15 Comp. Run 4 30 22 29 37 29 6 - W O 97/10924 PCT~US96/14668 The polycaprolactone materials in Runs l and 2 had ten times greater bending modulus than the comparison competitive materials in Runs 3 and 4.

Table 2e Run NumberFlexural Stren~,th (ASTM D 790-86) (MPal 2 3 4 MeanStandard Deviation 1 2.7 2.8 3.0 2.0 2.6 0.3 2 14.313.3 20.1 18.1 16.5 3.2 Comp. Run 3 0.5 1.3 0.7 0.7 0.8 0.4 Comp.Run 4 1.2 0.8 0.7 1.2 1.0 0.3 The polycaprolactone used in Run 2 had a flexural strength that was six times greater than the polycaprolactone used in Run l and fifteen times greater that the comparison competitive materials in Comp. Runs 3 and 4. As a result of having greater rigidity, the polycaprolactone materials should exhibit less flexing during normal lens processing conditions.

Hardness Test The hardness of the polycaprolactone materials used in Run l and 2 and - the competitive materials in Comp. Runs 3 and 4 was dett?rTnined using a nanoin~lent:~tion method. An ultramicro hardness tester, "UMISTM 2000 Tester"
from Division of Applied Physics, CSIRO, Australia was used. A Berkovich diamond indenter with a cone angle of 65 degrees was impressed against a surface in load increments of l mN while the resultant displacement was measured until the maximum load of 60 mN was achieved, then the load was incrementally decreased at l mN and the material's elastic recovery was observed2 o as a decrease in total penetration. The hardness is equal to maximum load divided by the projected area of plastic deformation (i.e. contact area) and is reported in giga-pascals (GPa). The results are shown in Table 2f.

Table 2f Run Number Ha~ness (GPa) 5.02 2 5.29 Comp. Run 3 0.00187 Comp. Run 4 0.14 The polycaprolactones, Runs l and 2, were significantly harder than the competitive materials, Comp. Runs 3 and 4.

Probe Tack Test A probe tack test was used to evaluate the tzl~kinec~ of the materials and is described in ASTM D2979-88. Alllmimlm tins, 57 mm in diameter, were tared and three grams of each polycaprolactone (Runs l and 2) and each competitive material (Comp. Runs 3 and 4) were added to a tin. The materials were melted on lo a standard hot plate and cooled for 2 minlltes A 25.4 mm by 25.4 m~n square of the material including the alllminllm beneath the material was scissors cut and placed on the test probe area of a "TMI Polyken Probetack (Model 80-02-Ol)"
commercially available from Testing Machines Inc., Amityville, NY with an "A"
annular weight of 200 grams (foarn side down) on top of the alllminnm side of the sample and the material side directly on top of the test probe. The m~hine settings were: Speed - 0.5 cm; Dwell time: 2 seconds; Mode: peak. The test was initi~tt--1 and the peak value recorded in grarns. The results are shown in Table 2g.
T~ble 2g R~un Number 1 2 3 4 5 Meall Standa}d (g) (g) ~g) (g) (g) tackDeviat~on ~g) ~g) Comp.Run3 115 109 110 90 102 105 10 Comp. Run 4 1190 14621474 10901067 1257198 The probe tack test showed that "FREE BONDTM Non-alloy Blocking 2 o Substance" (Comp. Run 4) was significantly stickier than the polycaprolactone - W O 97/10924 PCT~US96/14668 materials (Runs 1 and 2) and "OPTIKTM Feather Lite Blocking Compound (Comp. Run 3). Thus, "FREE BONDTM Non-alloy Blocking Substance" would be stickier around the laboratory and more difficult to clean from surfaces.

Shear Adhesion Test Circular polymethacrylate resin mounts were made and then ground using Grade 120 silicon carbide paper-backed abrasive mounted on a lapidary wheel.
Further ~rin-ling and polishing of the mounts was carried out by mounting Grade 600 silicon carbide paper-backed abrasive on the lapidary wheel. Approximately l o 2.8 cm circles were cut from each of two commercially available tapes: A) "VENTURETM Tape", available from Venture Tape Corp., Rockland, MA; and B) "SURFACE SAVERTM #1640 Lens Surface Systems" available from 3M
Company, St. Paul, MN. The tape circles were applied to the resin mounts with the adhesive side of the tape on the smooth surface of the resin mount, rolled twice with a t~,vo inch hand roller, and placed on a round 0.5 cm mold made froma 2 mm thick "TEFLONTM Polytekafluoroethylene Sheet" with a S mm diameter circular hole through the sheet. The hole in each mold was filled using syringeswith melted polycaprolactone from Run 1 or 2, competitive materials from Comparison Runs 3 or 4, or a low-melting-temperature blocking alloy commercially available as "Coburn Blok-alloy 9916" from Coburn Optical Induskies, Muskogee, OK, Comp. Run 5. The materials were allowed to harden and the mold was removed leaving resin mounts with the applied tape sample molded to the polycaprolactone, competitive materials or blocking alloy.
Adhesive strength was evaluated by mounting the resin mount in a holder 2 5 clamped in the jaws of an "INSTRONTM Testing A~aldLus" with the polished mount surface oriented parallel to the direction of pull. A loop of 0.44 mm diameter wire was placed around the base of the hardened materials. The ends of the wire were clamped in the pulling jaw of the tensile testing apparatus, placing the bond in shear skess. The bond was stressed until it failed, using a crosshead speed of 2 mm/min. Shear adhesion values for 10 samples of each material were measured and the average and standard deviation recorded. The results are recorded in Table 2h.
Table 2h Run . Shea~ Adhesion Test Nur~ber Number Bonded out of Avcrage adhesion value Starlda}d Deviation 10 al ~ci~ ,ls (kg/cm2) (k-~cm~) ~'VENTURE"Sl J~AC~"VENll~RE "SURF~CE"VENTURE "SUREACE
T~pe" I SAVER Tape" SAVER ~ape"SAVER
L ens Lens Sur~acing L~ns Surfiacin~
Surfiacing Systcms'- Sy5teJ
Systçms" 2 8.15 18.12 1.66 1 61 2 0 10 _Tape Ripped Comp. 0 2 - 4.51 - 1.14 Run 3 Comp. 3 4 5.56 6.25 2.44 1.17 Run 4 Comp. 2 10 12.15 12.96 4.09 2.80 Run 5 "VENTURE'~ No. 455 Tape" ~ lly ava lable from Venture Tape Corp., Rockland, MA
"SURFACE SAVERrM #1640 Lens Surfacing Systems" . ~ available from 3M Company, St. Paul, MN

Lens Distortion Test A surface protection tape was made by blending two resins, "BYNELTM
3101 Acid and Acrylate Modified Ethylene Vinyl Acetate" (25 wt. %) from E. I.
o Du Pont de Nemours and Company, Wilmington, DE and "ATTANETM 4602 Ultra Low Density Ethylene/Octene Copolymer" (75 wt. %) from Dow Chemical Company, Midland, MI on a "Haake Rheocord extruder" (Model 252) commercially available from Haake Inc., Saddle Brook, NJ with a 1.9 cm diameter screw and with a length to diameter (L:D) ratio of 25: 1 to form the backing layer of the surface protection tape. The temperature was progressively increased from 177 ~C to 277 ~C from zone 1 to zone 3. The die temperature was 288 ~C.
A double coated tape commercially available as "3M Double Coated 1512 Tape" was applied to one side of the backing layer of the lens surface 2 o protective film and to 70 mm plastic lenses with 2.0-2.4 mm center thickness, - W O 97/10924 PCT~US96/14668 plano, finished uncut, "RLX PlusTM Scratch Resistant, Finished Lens in Hard Resin" from Signet Armorlite, Inc., San Marcos, CA using the 3M SURFACE
SAVER Applicator available from 3M. Air pressure was set at 0.02-0.03 MPa for the blocker comrnercially available as OPTEKTM Model 200 Blocker. A brass blocking ring was placed on the blocker and a 56 mm diameter Coburn Block from Coburn Company was placed into the ring such that the inlet in the block fit snugly over the rubber nozzle. The block was centered on the lens and slowly filled with polycaprolactone from Run 1 at 60~C. The blocked lens assembly was allowed to set for 10 to 15 seconds after filling, in order for the resin to harden o and form a good bond to the taped lens. The blocking ring and blocked lens was removed from the blocker and the blocked lens was removed from the blocking ring.
The heat transfer temperature of the melted polycaprolactone was measured at the lens surface using a temperature probe sandwiched between the lens surface and the adhesive side of the surface protector tape. The results are shown in Table 2i.
Table~i Time(minutes) T~ . a~ul ~ (~C) 0 25.56 1 36.67 2 36.11 3 36.11 4 36.11 35.56 6 35.00 7 34.44 8 34.44 9 33. 9 33. 9 Il 33.
12 33.8 13 33.8 14 33.33 33.33 16 33.33 - W O 97/10924 -72- PCT~US96/14668 The lens were examined and found to be distortion "free" which means that it is safe to block such lenses with a surface protector tape at 60 ~C.

Cooling Rates The cooling rates of the polycaprolactones, Runs 1 and 2, were compared to the blocking alloy commercially available as "Coburn Blok-alloy 9916" from Coburn Optical Industries, Comp. Run 5, and the competitive material used in Comp. Run 4. An Omega Model HH2 1 microprocessor therrnometer type J-K-T
thermocouple was placed below the tape and against the lens. The results are 0 shown in Table 2j.
Table2j Time T~ lalul~(~C) (M~utes) Runl Run2 Comp.Run4 Comp.RunS
1 66.67 67.22 65.56 66.67 2 62.78 63.89 62.22 61.67 3 63.33 61.11 57.78 57.22 4 58.89 58.89 55.56 53.89 56.67 56.67 52.78 50.56 6 52.78 54.44 47.78 47.78 7 50.00 53.33 45.00 45.56 8 50.00 51.67 43.'3 4~.44 9 48.33 50.00 38. 3 4~.89 46.67 48.33 40.~0 4 .00 Il 44.44 46.67 38.89 4 .00 12 43.89 45.'~ 37.7 4~.00 13 42.78 43.'~.1 4 -~~
14 41.67 42.-J~.l 4.. 00 40.56 41.6. : .56 45.00 38.89 '7.78 '333 45.00 40.00 '7.78 1.11 45.00 ~0.00 :8.33 :0.00 45.56 '7.78 37.78 28.89 45.56 '2.78 37.22 27.22 45.56 31.67 36.67 26.67 45.56 31.11 35.00 26.11 43.89 28.89 33.33 25.00 36.67 27.Z2 27.22 25.00 31.11 27.78 27.78 25.00 28.33 28.89 28.89 25.00 27.78 - W O 97/10924 PCT~US96/14668 Blocking alloy, Comp. Run 5, initially cooled faster than any of the other mzlt--ri~l~ in the first five mimltec and then after ten minutes it held at a temperature between 45.00 ~C and 45.56 ~C which was a slower cooling rate.
"FREE BONDTM Non-alloy Blocking Substance", Comp. Run 4, cooled more quickly than any of the other materials.

Example 3 Low molecular weight polycaprolactones commercially available as "TONETM Polyol 1270" (reported MW = 4,000), "TONETM Polyol 0260"
(reported MW= 3,000), and "TONETM Polyol 2241" (reported MW = 2,000) from Union Carbide Chemicals and Plastics Company Inc., Danbury, CT were blended with a higher molecular weight polycaprolactone (PCL) commercially available as "TONETM Polyol P-300" (reported MW = 10,000) from Union Carbide Chemicals and Plastics Company Inc. in the arnounts shown in Table 3a, Runs 1 - 12. The polycaprolactones were placed in a high density polyethylene container in an oven at 65 ~C until they were melted, approximately 2 hours. Thecontainer was placed in boiling water on a hot plate with a mechanical stirrer for a few mimltes The container was returned to a 65 ~C oven to deaerate the molten polymers. Then the molten polymers were poured onto a tray to cool to room 2 o temperature and solidify. Low molecular weight polycaprolactone triols (reported MW = 300, 530, and 1250) commercially available from Aldrich Chemical Co., Inc., Milwaukee, WI were added to the melt of the higher molecular weight polycaprolactone, Run 1, in varying amounts (Table 3a) in Runs 13-24.
Hardness was measured using two durometers commercially available as Model 307L for Shore Type 'D' and Model 306L for Shore Type 'A' from Pacific Tr~n~ cer Corporation, Los Angeles, CA according to ASTM D2240 -91.
Viscosity of the molten polymer mixtures were determined using a Brookfield viscometer, Model LVT, spindle No. 34 commercially available from W O 97/10924 PCT~US96/14668 Brookfield Engineeling Laboratories, Inc., Stoughton, MA at 60 ~C. The spindle end was immersed to about 0.6 cm in the melt and r~lin~ were taken at intervals for 5 to 10 minutes until the reading was constant. The viscosity in centipoise (cP) was calculated.

Table 3a -Rull Number High Molecularl~ow Low Hardness Viscosity Weight PCL ~ MolecularMolecular Shore (cP) (wt. %) WeightWeight PCL 'D~/'A' PCL Triol ~wt. %)(wt. %) 2 80 20~ 0 52/98 14800 4 40 60;~ 0 47/98 8000 80~ 0 7 80 20 ~ 0 46/98 11600 8 60 40 ~ 0 42/98 9 0 100~ 0 1500 13 90 0 lOS 50/-- 15000 0 0 1ooS 90 16 97.5 o 2 56 18400 18 90 0 106 30/__ 19 80 0 206 30/__ 0 306 30/__ "TONET~ Polyol P-300" poly~ ,,ula~Lu.,., available from Union Carbide Chemicals and Plastics Company, Inc., Danbury, CT
"TONETM Polyol 1270" polycc-~ available firom Union Carbide Chemicals and Plastics Company, Inc.
"TONETM Polyol 0260" pOly.,~.u,uia..~u.._ available &om Union Carbide Chemicals and Plastics Company, Inc.
"TONETM Polyol 2241" ~uly~a~ull ' available from Union Carbide Chemicals and Plastics Company, Inc.
5 Low molecular weight pG~ ulula~lu~ triol (reported MW = 1250) ~.ul..",~,- "y available from Aldrich Chemicai Co.. Inc., Milwaukee, Wl Low molecular weight pOly.,a~ -. ' triols (reported MW = 530) .u,.",.~ ,lly available from Aldrich Chemical Co., Inc.
7 Low molecuiar weight puly-.a,u-ulaclu-,~ triols (reported MW = 300) ~,ullll~ lly available from Aldrich Chemicai Co., Inc.

W O 97/109~4 PCT~US96/14668 The addition of lower molecular weight solid polycaprolactone in Runs 2 -12 helped to reduce the viscosity of the blend. The addition of low molecular weight polycaprolactone triol in Runs 13 - 24 served as a plasticizer m~kin~ thepolycaprolactone blend soft while decreasing viscosity.
Example 4 Carbon black comrnercially available as "AROSPHERE 11" from Huber Corp., Borger, TX and a black inorganic pigment commercially available as "F-6331 " from Ferro Corporation, Color Division, Cleveland, OH were added in the amounts shown in Table 4a to a polycaprolactone comrnercially available as "TONETM Polyol P-300" (10,000 molecular weight) from Union Carbide Chemicals and Plastics Company, Inc. Ceramic microspheres commercially available as "ZEEOSPHERESTM 200" from 3M Company, St. Paul, MN were added in the amounts shown in Table 4a to a polycaprolactone commercially available as "TONETM Polyol 1270" (4,000 molecular weight) from Union Carbide Chemicals and Plastics Company, Inc. The polycaprolactone and carbon black, pigment, or microspheres were placed in a HDPE container in an oven at 65 ~C until the polycaprolactone was melted. Then the container was placed in boiling water on a hot plate with a mechanical stirrer for a few minlltes The 2 o container was placed back in a 65 ~C oven to deaerate. The molten polymer fi~ e was poured into an anodized alllmimlm metal block commercially available from Coburn, Muskogee, OK, covered with a polyethylene film, and molded in a concave shape. The block was cooled and the polycaprolactone mixture solidified. The melting time was evaluated by observing the time in seconds that the polymer mixture took to melt at 65 ~C under a 500 watt GE sun lamp held at a distance of 125 rnm from the surface of the polymer.
The polycaprolactone mixtures were also evaluated for hardness. The results are shown in Table 4a. Hardness was measured using ASTM D2240 - 91 "Shore Type 'D"'.

-W O 97/10924 PCTrUS96/14668 . Table4a Rlln PCL l~organic: Carbon Ceramic ~e~ting Hardncss Number ~wt. %~pigment3Black4 ~u7~ sTime Shvre (wt. %1~wt. %~ ~wt. %~ ~second~3~ "D"
00' 0 0 0 >1, 0 : 3 2 ~5' 5 0 0 10- 5 ~ 4 3 ~0' 10 0 0 10- 5 ~7 4 ~5' 0 5 0 10-15 ~ 3 ~0' 0 10 0 10-15 3 6 0' 0 0 20 10 45 7 100' 0 0 0 ~60 40 "TONET'/ Polyol P-300'- pol~ ' avai able ftom Union Carbide Chemicals and Pl~qtics Company, Inc., Danbury, Cl "TONETM Polyol 1270" pOIy~ ' available from Union Carbide Chemicals and Plastics Company, Inc.
3 "F-633 1 " black inorganic pigment available fiom Ferro C~ r~ Color Division, Cleveland, Ol I
"AROSPHERE 11 " carbon black available from Huber Ct~rnrs.~io~-, Borger, l~C
5 "ZEEOSPHERES~ Z-Z00" ceramic J~ h~,.c:- available from 3M Company, St. Paul, MN

The carbon black, the black inorganic pigment, and the ceramic microspheres increased the hardness of the polycaprolactone. Since both carbon 10 black and the pigment are able to absorb heat and light very quickly, they have a potential advantage of fast heating and cooling for lens blocking applications. In general, the black inorganic pigment blended with the polycaprolactone more easily than the carbon black.

Example 5 Low tt;lllp~. dlule melting plastics: candle wax, Gerber wax from Gerber Optical Inc., South Windsor, CT, and Exxon Ethylene Vinyl Acetate (MV 02528) from Exxon Company, Houston, TX were each mixed with 30 weight percent carbon black comrnercially available as "AROSPHERE 11 " from Huber Corp., 2 o Borger, TX . The waxes and carbon black were placed in a HDPE container in an oven at 85 ~C until the waxes melted. Then the container was placed in boiling water on a hot plate with a mechanical stirrer for a few minlltes The container was placed back in a 65 ~C oven to deaerate. The molten polymer mixture was poured into a tray and allowed to cool and solidify. The melting time was 2 5 evaluated by observing the time in seconds that the wax mixture took to melt at 65 ~C under a 500 watt GE sun lamp held at a distance of 125 mrn from the W O 97/10924 PCT~US96/14668 surface of the polymer. Hardness was measured using ASTM D2240 - 91 " Shore Type 'D'".
-Table 5a Rull Numb~rI o~f MeltingCa~bon B}ackMelting Time IIa~
~wt. ~/0~ (Wt. %) (seconds~ ~'D'~"A'~
ethylene vinyl 30 15 acetate 2 candle wax 30 10 3 wax' 30 S 28/88 ~'Exxon Ethylene vinyl acetate (MV 02528)" available from Exxon Chemical Company, Houston, TX
"Gerber wax" available from Gerber Optical Inc., Sou~ Windsor, CT

Low melting plastics mixed with a heat absorbing m~eri~l such as carbon black had sufficiently low melting times to be useful as a blocking m~teri~l Blending carbon black, black pigment or ceramic microspheres increased o hardness The wax used in Run 3 had a hardness of 22D before adding the carbon black Example 6 Two resins were blended on a "Haake Rheocord Extruder" (Model 252) commercially available from Haake Inc, Saddle Brook, NJ with a 1.9 cm diameter screw and with a length to diameter (L:D) ratio of 25:1 to form the backing layer of the surface protection tape. The amounts and types of resins are listed in Table 6a. The temperature of the extruder inlet was m~int:~ined at 1 49~C.
The extruder outlet and neck tube temperatures were kept at the same 2 o temperatures, 177 ~C. The die temperature was 204 ~C.
The deblock test was used to measure the deblocking force required to separate a blocked lens from the block. A double coated tape commercially available as "3M Double Coated 1512 Tape" was applied to one side ofthe - backing layer of the lens surface protective film and to 70 mm plastic lenses with - W O97/10924 PCT~US96/14668 2.0-2.4 mm center thickness, plano, finished uncut, "RLX PlusTM Scratch p~eci~t~nt, Finished Lens in Hard Resin" from Signet Armorlite, Inc. using the 3M SURFACE SAVER Applicator with an air pressure setting of 0.28 MPa. Air pressure was set at 0.02-0.03 MPa for the blocker commercially available as OPTEKrM Model 200 Blocker. A brass blocking ring was placed on the blocker and a 56 mm diarneter Coburn Block from Coburn Company was placed into the ring such that the inlet in the block fit snugly over the rubber nozzle. The block was centered on the lens and slowly filled with polycaprolactone from Run 1. Theblocked lens assembly was allowed to set for 10 to 15 seconds after filling, in order for the resin to harden and form a good bond to the taped lens. The blocked lens was removed from the blocker and allowed to set for 1 hour before deblocking. The blocked lens was placed into the deblocking ring and the lens was taped to the deblocking ring using 1.27 cm wide filament tape. With the blocking tool facing downward, the blocked lens was placed in a hollow tube.
The diameter of the tube was much greater than the blocking tool and the tube was sufficiently thick to abruptly stop the lens by its perimeter. The blocked lens assembly was dropped starting at 2.5 cm and raised in 2.5 cm increments until the block separated from the tape or until 15.2 cm in height, then, raised and dropped in 5.1 cm increments up to 91.4 cm. The height in centimeters (cm) at which the 2 o block released from the tape was recorded as the deblock values in Table 6a.
Tensile Strength and Percent Elongation in the machine and cross m~hine directions were determined for Runs 1-7 using ASTM Test Method D
882 - 91 ("Standard Test Methods for Tensile Properties of Thin Plastic Sheeting" Test Method A: Static Weighing, Constant-Rate-of-Grip Separation Test) on an "INSTRONTM Model No. 1122 Tensile Tester" from Instron Corporation, Canton, MA. The films were tested in the machine direction and cross m~hine direction and the results of 3 samples in each direction were averaged. The crossheiqcl speed was 25.4 cm/min, size of sample was 10.2 cm - W O 97/10924 PCT~US96/14668 long, 2.54 cm wide, and 0.127 mm thick, and the distance between the grips was 5.08 cm.

Table6a Pcun C~ . Deblock Tensile Strength ~lumher ~alues Rcsi~ 1'Reshl2 ~m) MachineCross Machinc CrossDirection ~wt. %)~wt. %~ DirecffonDirectionDiree~ion - ~/o~
~MPa) (MPI) ~~/ ) 80' 15.2 0.098 0.066 624 638 2 20 80~ 15.2 0.134 0.107 737 799 3 40 604 20.3 4 40 60' 20.3 0.132 0.044 409 457 60~ 15.2 0.134 0.046 512 416 6 60 40~ 20.3 0.134 0.062 603 44-~
7 60 40j 30.5 0.134 0.069 612 46~
~ "ESTANETM 58309 Polyether Type Tl ~ . ~ rOI~ from The B. F. Goodrich Company, Clevelant, OH.
~ "BYNELTM E-374 Anhydride Modified Ethylene Acrylate" from E. 1. Du Pont de Nemours and Company, Wilmington, DE (now BYNEL 2174).
3 "AFE~INITYTM 1845 Very Low Density rol~ hJI.,..~," from Dow Chemical Company, Midland, Ml.
'-ASPUNTM 6806 Linear Low Density P~ ," from Dow Chemical Company, Midland, Ml.

Example 7 Runs 1-3 were plepal~d by melt blending the amounts and types of resins, waxes, and other additives described in Table 7a to form blocking compositions.

Table 7a 3~unNurnber Ethylene/VinylParaffin Wax'OtherAdditives Acetatel (parts) (parts~
(parts) 200 100 15.8 2 400 200 1.24 "ELVAXTM 210" (72 weight percent ethylene/28 weight percent vinyl acetate) from E. 1. Du Pont de Nemours and 15Company, Wilmington, DE.
~'SHELLWAXTM 200" from Shell Oil Company, Houston, TX.
"Dow Coming 360 Silicone Medical Fluid" (Z0 centipoise viscosity) from Dow Coming, Midland, Ml "GP-I Thixotrope" (N-lauroyl-L-glutamic acid di-n-butylamide) from Ajinomoto U.S.A., Inc., Teaneck, NJ.

~ 2 o In order to test the adhesion of the blocking compositions to a lens protection tape (commercially available as "SURFACE SAVERTM #1640 Lens Surface Systems" from 3M Company), a ceramic plate was clamped to the top of - W O 97/10924 PCT~US96/14668 a laboratory bench, the lens protection tape was placed adhesive side down on the plate and a TEFLONTM Coated Mold with four 1.3 cm diameter holes was placed on top of the backing of the tape. A blend from Run 1, 2, or 3 was placed in a container on a hot plate until it was melted. Then the molten blend was poured into the holes in the mold to a depth of 0.3 to 0.6 cm. The molten blend was allowed to cool to room temperature and solidify into cylinders. The cylinders of resin/wax blend were removed from the mold. The cylinders of solidified resin/wax blend were removed from the tape by pulling them off by hand. The cylinder made in Run 1 came off the easiest and marred the tape backing the o least. However, the cylinder would not come off by knocking it against the laboratory bench which is the usual method for deblocking a lens. The cylinder made in Run 2 was harder to remove than the one made in Run 1 and a little more m~rkin~ was observed on the tape backing surface. The cylinder made in Run 3 was the hardest to pull off the tape backing.
In a second experiment using the same resin/wax blends, an assembly of the mold on the tape b~-~kinp was clamped to a piece of acrylic film instead of the ceramic plate. Solid pieces of resin/wax blends from Runs 1, 2, or 3 were placedin the holes of the mold and the entire assembly was placed in an oven at 70~ C
until the resin/wax blend had melted and flowed. The assembly was allowed to 2 0 cool and the resin/wax blend solidified. The cylinders of resin/wax blends were removed from the mold and pulled offof the tape by hand. The resin/wax blend from Run 1 had very low adhesion to the backing and came off very easily. The blend from Run 2 was fairly hard to remove and left a little residue on the backing. The blend from Run 3 has hard to remove and left a lot of residue on the 2 5 b~qckin~

Example 8 Pieces of polycaprolactone (PCL) (commercially available as "TONETM
Polyol P-300" (lO,000 molecular weight) from Union Carbide Chemicals and - W O97/10924 PCT~US96/14668 Plastics Company Inc., Danbury, CT) were placed in the holes of the mold described in Example 7 and the entire assembly was placed in an oven at 70~ C
until the resin had melted and flowed. The assembly was allowed to cool and the resins solidified. The cylinders of resin were removed from the mold and pulled off of the tape by hand. PCL was as hard to remove from the tape backing as the cylinders in Example 7, Runs 2 and 3. In a second experiment the lens protectiontape in the assembly was replaced with an unprimed polyethylene terephthlate (PET) film. There was no adhesion of the PCL to the PET film. In a third experiment the PET film was replaced with a polyethylene film from a o "ZIPLOCTM Bag". The cylinders were very easily removed.

Example 9 Resins were made by blending the amounts and types of resins described in Table 9a to form blocking compositions.
Table 9a Run NurnberPOl~,alJIvlac~vllclFthylene/Yinyl Acetate (parts) ~part~
400 100' 2 400 100~
~-TONETU Polyot P-300'- (10,000 molecular weight) from Union Carbide Chemicals and Plastics Company Inc.
~-ELVAXTM 210" (72 weignt percent ethylene/28 weight percent vinyl acetate) (Melt Index 400) from E. 1. Du Pont de 3Nemours and Company ~-ELVAXTM 4969-6W" (72 weight percent etnylene/28 weight percent vinyl acetate) (Melt Index 1900) from E. 1. Du Pont de Nemours and Company Pieces of the resin blends from Run 1 or Run 2 were placed in the holes of the mold described in Example 7 and the entire assembly was placed in an oven at 70~ C until the resin blends had melted and flowed. The assembly was allowed to cool and the resin blends solidified. The cylinders of resin from Run 1 or Run 2 5 2 were removed from the mold and pulled off of the tape by hand. Cylinders of resin from Run 1 were removed easily but not too easily. The viscosity of the resin blend from Run 1 was fairly high. Cylinders of resin blends from Run 2 - W O 97/10924 PCT~US96/14668 were removed very easily and the viscosity of the resin blend from Run 2 was also fairly high.

Example lO
A resin was made by blending 8 parts polycaprolactone (cornmercially available as "TONETM Polyol P-300" (10,000 molecular weight) from Union Carbide Chemicals and Plastics Company Inc.) with 5 parts polycaprolactone (commercially available as "TONETM Polyol 221"(1000 molecular weight) from Union Carbide Chemicals and Plastics Company Inc.). Pieces of the resin were o placed in the holes of the mold described in Example 7 and the entire assembly was placed in an oven at 70~ C until the resin had melted and flowed. In this experiment the lens protection tape in the assembly was replaced with a polyethylene film from a "ZIPLOCTM Bag". The assembly was allowed to cool and the resin solidified. The cylinders were removed from the mold and pulled off of the tape by hand. The cylinders of resin were very easily removed from the film.
Melting points were determined using Differential Sç~nning Calorimetry (DSC) at a rate of 20~ C per minute from minus 50~ C to plus 150~ C. The resultsare reported in Table 1 Oa.
Table lOa Example No.fRun No.Melting Temperature (~ C) lo 58 Example ll Two layer lens surface protection tapes were coextruded in a one step process. The two layers were an outer film layer and an adhesive layer.
The resins used for the film layer comprised 60 parts "ESTANETM 58309 2 5 Polyether Type Thermoplastic Polyurethane" from the B. F. Goodrich Company;

CA 0222980l l998-02-l7 - W O 97/10924 PCT~US96/14668 34 parts AFFINITYTM 1845 Very Low Density Polyethylene" from Dow Chemical Company; and 6 parts "Green Pigment Number 1054" from Hoechst-Celanese Corp., Specialty Chemical Group, Coventry, Rl. The resins were blended using a 58 mm diameter twin screw extruder with a L:D ratio of 44:1 (available from Crompton & Knowles Corp., Davis Standard Division, Pawiatuck, CT). The t~lllp~,ldLulc; of the extruder inlet was m~int~ined at 38~Cand the extruder outlet and neck tube temperatures were m~int~ined at 149~C.
The target film layer caliper was 0.051 mm.
The adhesive layer was a 94 parts IOA /6 parts AA acrylic adhesive with 0.4% ABP crosslinker made by the process described in US Patent Numbers 4,737,559 and 4,847,137. The adhesive layer was processed using a 58 mm diameter twin screw extruder with a L:D ratio of 44:1 (available from Crompton & Knowles Corp.). The temperature of the extruder inlet was m~int~ined at 93~C, the extruder outlet was at 149~C, and the neck tube temperature was m~int~ined at l 66~C. The target adhesive layer caliper was 0.076 mm.
The melt flows from the two extruders were combined into one melt stream using a "CloerenTM Model 93-1123 feedblock" (available from The Cloeren Company, Orange, TX) and formed into a two layer film with the adhesive layer down using a "Cloeren EPOCHTM 3 Die" fabricated by The 2 o Cloeren Company. The feedblock and the die temperature were m~int~ined at 177~C. The film was extruded onto a silicone release liner. The adhesive was crosslinked by irr~ ting the tape from the film side using UV curing lamps (available from UVEX Inc., Sunnyvale, CA) with a light intensity of l 00 millijoules per square cm as measured by a Model M365 W Radiometer (from 2 5 Electronic Instrumentation and Technology Inc., Sterling, VA). The target caliper for the adhesive was 0.076 rnm.
The tape was evaluated for deblock force using the Deblock Test described in Example 6 except the double coated tape was not used to attach the tape to the lens surface. The average deblock value was 58.4 cm.

- WO 97/10924 PCT~US96/14668 Example 12 Two layer lens surface protection tapes were coextruded in a one step process.
The resins used for the film layer comprised 56 parts "PELLETHANETM
2103-9OAE Polytetramethylene Glycol Ether Thermoplastic Polyurethane Elastomers" from Dow Chemical Company; 38 parts "ENGAGETM 8200 Polyolefin Elastomer" from Dow Chemical Company, and 6 parts "Green Pigment Number 1054" from Hoechst-Celanese Corp. The resins were blended 1 o using the twin screw extruder described in Example 11. The temperature of the extruder inlet was m~int~ined at 21~C and the extruder outlet and neck tube temperatures were m~int~ined at 166~C. The target film layer caliper was 0.051 mm.
The adhesive layer was the same as that described in Example 11. The adhesive layer was processed using the twin screw extruder described in Example 11. The temperature of the extruder inlet was m~int:~ined at 93~C, the extruder outlet was at 149~C, and the neck tube temperature varied from 177~C to 193~C.
The target adhesive layer caliper was 0.076 mm.
The melt flows from the two extruders were combined into one melt 2 o stream as described in Example 11. The feedblock temperature was m~int~ined at 177~C and the die temperature was m~int:~ined at 179~C. The film was extruded onto a silicone release liner. The adhesive was cro~slinked by irr~ tinp; the tape from the film side using UV curing lamps (available from UVEX Inc.) with a light intensity of 150 millijoules per square cm as measured by a Model M365 2 s UV Radiometer (from Electronic Instrllment~tion and Technology Inc.). The target caliper for the adhesive was 0.076 mm.

- W O 97/10924 PCT~US96/14668 F, ~ 13 Polycaprolactone (PCL) materials available as "CAPATM poly(~-caprolactone) diol" (10,000 molecular weight) from Solvay Interox, Houston, TX, Run 1, were blended with a lower viscosity material, stearic acid (SA) available from J. T. Baker, Phillipsburg, NJ, in the amounts shown in Table 13a, Runs 2-5. The lower viscosity material, SA, was heated in an ~ minllm tin until liquified and allowed to cool and solidify. The PCL was heated in an ~ll,...i,.l.,~ tin on a hot plate to about 100~C. Chunks of SA were broken off and added slowly to the molten PCL while stirring mech~nir~lly.
Table 13h ~:unPolycaprolactone Stearic Acid Number(weight percent) (weight percent) Viscosity of the molten PCL/SA ~ u,~;:s was determined using a Brookfield Viscometer as described in Example 3.
Hot melt blends of PCL/SA were poured into a Coburn block, then covered with polyethylene terephth~l~t~ film and allowed to solidify. Hardness was measured using a durometer for Shore type LD' as described in Exarnple 3 after 10, 20, and 30 mimlt~s of cooling. The solidified PCL/SA mi~lule was inspected for cracking on the surface. The time required for the molten PCL/SA llli~Ul~, to solidify was measured. The results of viscosity and hardness testing as well as the presence or absence of cracks and the set-up time 2 o are reported in Table 13b.

CA 0222980l l998-02-l7 Table 13b ~un Viscosi~y Shore "D" HardnessCrackingSet-up Number (cp) (yes or Time no) (seconds~
10 min20 min 30 rnin 30,000 37 41 44 no > 30 2 18,000 37 39 38 no 10-15 3 14,400 27 30 36 no 4 10,600 24 28 34 no 8,300 20 27 30 no The viscosity of PCL was decreased by a factor of about 4 when 20 percent SA was added to the melt.

F,Y~mrl~ 14 Polycaprolactone (PCL) materials available as "CAPATM poly(~-caprolactone) diol" (10,000 molecular weight) from Solvay Interox, Houston, TX, were blended with a lower viscosity material, stearyl alcohol (SAL) or 1-oct~lleç~n~ l available from Aldrich Chf nnic~l Colllpally, Milwaukee, WI, as 0 described in Example 13 in the amounts shown in Table 14a.
Table 14~t ~n Polycaprolactone Stearyl alcohol Number (weight percent) (weight percent~

The blocking compositions of molten PCL/SAL blends were evaluated for viscosity, hardness, and cracking, as described for Example 13. The results are reported in Table 14b.

- W O 97/10924 PCT~US96/14668 Table 14b Run Viscosi~Shore "D" HardnessCracking Number (cp~ ~yes or no) lQ min 20 min30 min ~ 1 30,000 37 41 44 no 2 16,600 35 39 43 no 3 12,200 24 29 31 no 4 8,920 19 24 28 no 6,720 18 24 27 no SAL is less acidic than SA.

Example 15 Polycaprolactone (PCL) materials available as "CAPATM poly(~-caprolactone) diol" (10,000 molecular weight) from Solvay Interox, Houston, TX, were blended with lower viscosity materials, stearic acid (SA) and stearyl alcohol (SAL). Chunks of soliclifif ~l, blended SA and SAL in a ratio of 64 parts by weight SA to 36 parts by weight SAL were added to the molten PCL as described in Example 13 in the amounts shown in Table 15a.
Table 15~
Run PolycaprolactoneStearic Acid.Stearyl alcohol Number ~weight percent) (weight percent) The blocking compositions of molten PCL/SAL blends were evaluated for viscosity, hardness, and cracking as described for Example 13. The results are reported in Table l5b.

Table l5b Run ViscosityShore "D" HardnessCracking ~umber ~cp) (yes or no) 10 min20 min 30 min 30,000 37 41 44 no 2 17,900 34 41 41 no 3 12,400 ~2 35 36 no 4 8,000 ~8 32 32 no 5,500 27 31 31 no The blend solidified faster than PCL alone.

~,Y~mrl~ 16 Polycaprolactone (PCL) materials available as "TONETM P-300 polycaprolactone" (10,000 molecular weight) from Union Carbide Corporation, Danbury, CT were blended with a lower viscosity material, tri-phenyl phosphate (TPP) available from Monsanto Chf mir~l Company, St. Louis, MO, as described in Example 13 in the amounts shown in Table 16a.
Table 16i.
Run Polycaprolactone Tri-phenyl phosphate ~umber (weight percent) (weightpercent) The blocking compositions of molten PCL/TPP blends were evaluated for viscosity, llaldlless, and cracking as described for Example 13. The resultsare reported in Table 16b.

Table 16b :~un ViscosityShore "D" HardnessG~chi~1g Number (cp~ ~yes or no) 10 min 20 min 30 min ~ 1 54,000 37 41 44 no 2 44,200 38 40 41 no 3 35,500 34 35 36 no 4 30,000 30 31 31 no The viscosity of PCL was decreased by a factor of about 2 when 15 percent TPP was added to the melt.

l~ nrle 17 Polycaprolactone materials available as "CAPATM poly(~-caprolactone) diol" (10,000 molecular weight) from Solvay Interox, Houston, TX, were blended with a lower viscosity material, myristyl alcohol (MAL) (1-tetradecanol) available from Aldrich Chemical Co~ ally as described in Example 13 in the amounts shown in Table 17a.
Table 17~
~un Polycaprolactone Myristyl alcohol Number (weight percent) (weight percent) The blocking compositions of molten PCL/MAL blends were evaluated for viscosity as described for Example 3 except spindle no. 16 was used. The molten blends were poured into a mold, allowed to cool and solidify, and evaluated for Tangent Modulus of Elasticity in Bending and Flexural Strength as described for Example 2 except the crosshead motion was 2.8 mm per minute. The results are reported in Tables 17b and 17c.

W O 97/10924 PCTnUS96/14668 Table 17b Run Tangent Modulus of Elasticity in Bending Number Number of MeanStandard Deviation S~mI-lçs (MPa) (MPa~

Table 17c Run Flexural Strength Number Number of MeanStandard Deviation Samples (MPa) (MPa) 3.3 0.3 ~,Y~mrle 18 Polycaprolactone materials available as "CAPATM poly(~-caprolactone) diol" (10,000 molecular weight) from Solvay Interox, Houston, TX were blended with lower viscosity materials, myristyl alcohol (MAL) (1-tetra~itoc~nol) and stearyl alcohol (SAL) (1-octadeconol) available from Aldrich Chemical G~ ally. Chunks of blended and solidified MAL and SAL were added as described in Example 13 in the amounts shown in Table 18a.
T-*le 18a Run PolycaprolactoneMyristyl alcoholStearyl alcohol Number (weight percent)(weight percent~(weight percent) The blocking compositions of molten PCL/MAL/SAL blends were evaluated for viscosity as described for Example 3, except spindle no. 16 was used. The molten blends were poured into a mold, allowed to cool and solidify, and evaluated for Tangent Modulus of Elasticity in Bending and Flexural - W O 97/10924 PCT~US96/14668 Strength as described for Example 2 except the crosshead motion was 2.8 mm per minute. The results are reported in Tables 18b and 18c.
Table 18b Run Viscosity Tangent Modulus of Elasticity in Bending Number (cp) Number of MeanS~andard Deviation Samples (MPa) ~MPa~
6,000 5 436 31 2 6,000 5 506 29 3 5,900 5 454 34 4 5,800 5 471 39 Table 18c Run Flexural Strength Number Number of Mean Standard Deviation Samples (MPa) (MPa) 3.2 0.4 2 5 3.2 0.3 3 5 3.3 0.2 4 5 3.5 0.3 Example 19 Polycaprolactone materials available as "CAPATM poly(~-caprolactone) diol" (10,000 molecular weight) from Solvay Interox, Houston, TX were blended with lower viscosity materials, dodecyl alcohol (DO) (1-odecanol) available from Eastman Chemical Company, Kingsport, TN, myristyl alcohol (MAL) (1-tetr~1ec~nol) and stearyl alcohol (SAL) (1-octadeconol) available from Aldrich Chtomi~l Company. Chunks of blended and solidified DO, MAL, and SAL were added as described in Example 13 in the amounts shown in Table 19a.

- W O 97/10924 PCT~US96/14668 Table l9a - RunPolycaprolactone( DodecylMyristyl Stearyl Numberweight percent) alcoholalcohol alcohol (weight~weight (weight percent) percent) percent) 0.1 1.7 3.2 2 90 0.2 3.4 6.4 3 85 0.3 5.1 9.6 4 80 0.4 6.8 12.8 The blocking compositions of molten PCL/DO/MAL/SAL blends were evaluated for viscosity as described for Example 3 except spindle no. 16 was used. The molten blends were poured into a mold, allowed to cool and solidify, and evaluated for Tangent Modulus of Elasticity in Bending and Flexural Strength as described for Example 2 except the crosshead motion was 2.8 mm per minute. The results are reported in Tables l9b and l9c.
Table l9b Run Viscosity Tangent Modulus of Elasticity inBending NumbeF {cp~
Number of Mean Standard Deviation Samples (MPa) ~MPa) 16,400 5 566 49 2 11,600 5 521 15 3 7,800 5 447 42 4 5,600 5 509 30 Table l9c ~un Flexural Strength Number Number of Samples Mean Standard Deviation (MPa) ~MPa) 1 5 1.9 0.03 2 5 2.3 0.2 3 5 2.3 0.1 4 5 3.2 0.2 - W O 97/10924 PCT~US96/14668 ~ n~1~.20 Polycaprolactone materials available as "CAPATM poly(~-caprolactone) diol" (10,000 molecular weight) from Solvay Interox, Houston, TX were blended with polyethylene glycol methyl ether (2,000 molecular weight) (PEGME) available from Aldrich Ch~mic~l Co~ ally as described in Example 13 in the amounts shown in Table 20a.
Table 20a RunPolycaprolactonePolyethylene glycol methyl ether Number(weight percent)(weightpercent~

The molten PCL/PEGMA blends were poured into a mold, allowed to cool and solidify, and evaluated for Tangent Modulus of Elasticity in Bending lo and Flexural Strength as described for Example 2 except the crosshead motion was 2.8 mm per minute. The results are reported in Tables 20b and 20c.
Table 20b Run Tangent Modulus of Elasticity in Bending Number Number of MeanStandard Deviation Samples ~MPa) (MPa) Table 20c Run Flexural Streng~
Nuraber Number of MeanStandard Deviation Samples (MPa) (MPa~
2.6 0.2 2 5 3.5 0.3 3 5 3.2 0.4 ~,Y~mpl~ 21 Polycaprolactone materials available as "CAPATM poly(~-caprolactone) diol" (8,000 molecular weight), "CAPATM poly(~-caprolactone) diol" (10,000 molecular weight) ,and "CAPATM poly(~-caprolactone) diol" (12,000 molecular weight) from Solvay Interox were blended with polyethylene ethylene glycol (1500 or 2000 molecular weight (MW)) (PEG) available from Aldrich Chemical Company as described in Example 13 in the amounts shown in Table 21a.

Table 21a Run PolycaprolactonePolyethylene ethylene glycol Number ~weight perce~t) (weight percent~
"P-8K"' "P-lOK"~ "P-12K"3 1500 MW 2000 MW

6 ~ ~ 90 ~ 10 1 "CAPATM poly(~~},., 1?) diol' (8.000 molecular ~ Solvay Interox. Houston. ~X.2 '-CAPATM poly(~~~ ' ) diol'- (10.000 molecular ~ Solvay Interox.
3 '-CAPAT~ poly(~ ~ ) diol~ (12,1)00 molecular ~ Solvay Interox.
The blocking compositions of molten PCL/PEG blends were evaluated for viscosity as described for Example 3 except spindle no. 16 was used. The molten blends were poured into a mold, allowed to cool and solidify, and evaluated for Tangent Modulus of Elasticity in Bending and Flexural Strength as described for Example 2 except the crosshead motion was 2.8 mm per minute. The results are reported in Tables 21b and 21c.

_95 _ Table 21b Run Viscosity Tangent Modulus of Elasticity in Bending Number (cp) Number of MeanSt~n~l~r~l Deviation -Samples (MPa) (MPa~
17,000 5 419 22 ~ 2 11,000 5 404 35 3 8,300 5 493 17 4 6,200 5 430 64 16,200 5 525 42 6 31,000 4 454 34 Table 21c Run Flexural Strength Number Number of Samples Mean Standard Deviatior (MPa) (MPa) 3.4 0.5 2 5 2.1 0.7 3 5 2.4 0.3 4 5 4.2 0.9 2.0 0.3 6 4 3.0 0.5 h~ m~ 22 High molecular weight polycaprolactone materials available as "CAPATM
630" (30,000 molecular weight) from Solvay Interox were blended with lower viscosity materials, a low molecular weight polycaprolactone available as "TONETM P-1270" (4,000 molecular weight) from Union Carbide Chemicals and Plastics Company Inc. polycaprolactone (PCL) and, myristyl alcohol (MAL) (l-tetr;~ c~nol) available from Aldrich Chemical G~ ally. Chunks of a low molecular weight PCL and MAL were added as described in Example 13 in the amounts shown in Table 22a.

-WO97/10924 PCTrUS96/14668 Table 22a RlmPolycaprolactone Myristyl alcohol Number~weight percent)(weight percent) "CAPATM 630 T(:~NETM p 1270" ~

lIy available from Solvay Interox, Houston, 17~.
(' ~,i~.lly available from Union Carbide Chemicals and Plastics Company Inc.. Danbuly, CT.
The blocking compositions of molten PCL/MAL blends were evaluated for viscosity as described for Example 3 except spindle no. 16 was used. The molten blends were poured into a mold, allowed to cool and solidify, and evaluated for Tangent Modulus of Elasticity in Bending and Flexural Strength as described for Example 2 except the crosshead motion was 2.8 mm per minute. The results are reported in Tables 22b and 22c.

Table 22b RunViscosity TangentModulus of Elasticity in Bending Number (cp) Number of MeanSt~n-l~rd Samples ~Pa)Deviation ~MPa) 22,000 5 336 23 2 22,000 5 396 24 Table 22c Run Flexural Strength Number Number of MeanStandard Deviation Samples (MPa) 5.0 0.7 2 5 4.4 0.4 Example 23 High molecular weight polycaprolactone materials available as "CAPATM
630" (30,000 molecular weight) from Solvay Interox were blended with lower CA 0222980l l998-02-l7 viscosity materials, a low molecular weight polycaprolactone available as "TONETM P-1270" from Union Carbide Chemicals and Plastics Co~ ally Inc.
polycaprolactone (PCL), myristyl alcohol (MAL) (l-tetraclec~n~-l) and stearyl alcohol (SAL) (l-octadeconol) available from Aldrich Chemical C~ lly.
Chunks of blended and solidified low molecular weight PCL, MAL, and SAL
were added as described in Example 13 in the amounts shown in Table 23a.

Table ''3a RunPolycaprolactone Myristyl alcoholStearyl alcohol ~umber~weightpercent) (weight percent) ~weight percent~
CAPATM TONETM
630"1 P-1270~ 2 available from Solvay Interox. Houston. TX.
2 t~ available from Union Carbide Chemicals and Plastics Company Inc.. Danbury. CT.
The blocking compositions of molten PCL/MAL/SAL blends were evaluated for viscosity as described for Example 3 except spindle no. 16 was used. The molten blends were poured into a mold, allowed to cool and solidify, and evaluated for Tangent Modulus of Elasticity in Bending and Flexural Strength as described for Example 2 except the crosshead motion was 2.8 mm per minute. The results are reported in Tables 23b and 23c.
Table 23b RuiuViscosity Tangent Modulus of Elasticity in Bending Number (cp) Number of Mean Standard Samples (~IPa)Deviation ~MPa) 21,000 5 303 66 Table 23c ~un Flexural Strength Number ~umber of Mean Standard Deviation ~amples (MPa) 4.6 0.6 Example 24 High molecular weight polycaprolactone materials available as "CAPATM
630" (30,000 molecular weight) from Solvay Interox were blended with lower viscosity materials, a low molecular weight polycaprolactone material available as "TONETM P-1270" (4,000 molecular weight) from Union Carbide Chemicals and Plastics Co~ ally Inc. polycaprolactone (PCL), myristyl alcohol (MAL) (1-tetr~tlecanol), stearyl alcohol (SAL) (l-octadeconol) and polyethylene glycol (PEG) available from Aldrich ChPrnir~l Company. Chunks of blended and 0 solidified low molecular weight PCL, MAL, Sal, and PEG were added as described in Example 13 in the amounts shown in Table 24a.

Tab e 24a Run Polycaprolactone Myristyl Stearyl Polyethylene - Number (weight percent) alcohol alcohol Glycol (weight (weight ~weight percent) percent) pcr~ellL) "CAPATM "TONETM
630n l P-127~

available from Solvay Interox, Houston. TX.
2 ~ available from Union Carbide Chemicals and Plastics Company Inc., Danbury, CT.
The blocking compositions of molten PCL/MAL/SAL/PEG blends were evaluated for viscosity as described for Example 3 except spindle no. 16 was _99_ used. The molten blends were poured into a mold, allowed to cool and solidify, and evaluated for Tangent Modulus of Elasticity in Bending and Flexural Strength as described for Example 2 except the crosshead motion was 2.8 mm per minute. The results are reported in Tables 24b and 24c.
Table 24b RunViscosity Tangent Modulus of Elasticity in Bending Number~cp) Number of Mean Standard Samples (MPa)Deviation (MPa~
18,000 5 319 24 2 13,000 5 255 26 3 14,000 3 290 5 4 17,000 5 316 35 Table 24c l~un Flexural Strength Number Number of MeanStandard Deviation Samples (MPa) ~.6 0.6 2 5 ~.3 0.3 3 3 ~.4 0.1 4 5 3.7 0.6 ~,y~m~l~ 2~
Three layer lens surface protection tapes were coextruded in a one step process. The three layers were an outer film layer (skin), a tie layer (core) and an adhesive layer. The compositions of the various layers used to make the tapes are given in Table 25a. The target thickness for the outer film layer, tielayer, and adhesive layer are reported in Table 25b.
The outer film layer was either a blend of polycaprolactone (PCL) lS (available as "CAPATM 650" from Solvay Interox) and a maleic anhydride modified ethylene acrylate (available as "Bynel 2174" from DuPont Packaging - W O 97/10924 PCT~US96/14668 & Industrial Polymers, Wilmington, DE) and a maleic anhydride modified linear low density polyethylene (available as "Bynel 4109" from DuPont Packaging & Industrial Polymers) or a blend of the PCL and a maleic anhydride modified low density polyethylene (available as "Bynel 4206" from DuPont Pack~ing & Industrial Polymers). Three percent of a pigment (available as "OSELD-1054" from Resco Colours a division of Hoechst, Missi~s~ , Ontario) was added to this blend. The resins and pigment as described in Table 25a were blended using a 58 mm ~ mt-ter twin screw extruder with a length to ~ m~t~r (L:D) ratio of 44: 1 (available from Crompton & Knowles Corp., Davis Standard Division). The temperature of the extruder inlet was m~int~in~od at 21~C and the extruder outlet and neck tube t~ ,eldtureswere m~int~in~l at 193~C.
The tie layer was made from a nylon 6/6,9 copolymer (available as "GRILONTM CF62BSE Nylon 6/6~9 Copolymer" from EMS-American Grilon Inc., Sumter, SC). The tie layer (core) was processed using a 6.35 cm (2.5 inch) ~ m~oter single screw extruder with a length to ~ mloter (L:D) ratio of 30:1 (available from Crompton & Knowles Corp., Davis Standard Division).
The temperature of the extruder inlet was m~int~in~d at 66~C and the extruder outlet and neck tube temp~dlules were m~int~in~l at 177~C.
2 o The adhesive layer was made from a 94 parts IOA /6 parts AA acrylic adhesive with 0.4% ABP crosslinker made by the process described in US
Patent Numbers 4,737,559 and 4,847,137. The adhesive layer was processed using a 58 mrn ~ m.?ter twin screw extruder with a length to ~ m~ot~r (L:D) ratio of 44: 1 (available from C1O111PL~n & Knowles Corp., Davis Standard Division). The temperature of the extruder inlet was m~int~in~-i at 93~C and the extruder outlet and neck tube te"l~eldtures were m~int~in.-~l at 177~C.
The melt streams from the three extruders were combined into one melt stream using a "CloerenTM Model 92-1033 feedblock" (available from The Cloeren Company) and formed into a film using a Cloeren Epoch die fabricated by The Cloeren Coml?ally. The feedblock ~lllpel~Lule was m~int~in~l at 177~C
and the die temperature was m~int~in~l at 179~C.
The adhesive was crosslinked by irr2~ tin~ the tape from the adhesive side using UV curing lamps (available from UVEX Inc., Sunnyvale, CA) with a ~ 5 light illLel,si~y of 84 millijoules/square cm as measured by a Model M365 UV
Radiometer (from Electronic Instrumentation and Technology Inc., Sterling, VA) in the 320 to 390 nm range.

Table 25a Run Composition Number Film Layerl Tie Layer Adhesive - L~yer Resin 12Resin 23Resin 34 Resin 45 Resin6 Adhesive7 (wt. %) (wt. %) (wt. %) (wt. %) ~wt. %) ~wt. %) ' The Film Layer of Runs 1-5 also contain 3 we ght percent pigment, . 'l~ available as "05F-.LD-1054~ from Resco Colours a Division of Hoecbst. 1~ Ontario.
Z ('~ available as ''CAPATM 650 ~l~, ,ulvh.lul.~," from Solvay Interox, Houston. lX.
3 (' ~,;..11,~ available as ~Bynel 4206 maleic anhydride modified low density ,vul~.,~l.,-~ from DuPont Packaging & Industrial Polymers, ~i' DE.
4 C ' ~'~, available as "Bynel 2174 maleic anhydride modified etbylene acrylate~ from DuPont Packaging &
Indusrrial Polymers.
5 ('' ' ~ available as Bynel 4109 maleic anhydride modified linear low density pGI,~ ." from DuPont Packaging & Industrial Polymers.
6 C, ' ".~ available as '-GRILONTM CFo2BSE Nylon 6/6,9 Copolymer" from EMS-American Grilon Inc., Sumter, SC.
2 0 7 94 parts IOA /6 parts AA with 0.4% ABP crosslinker. made by tne process described in US Patent Numbers 4,737,559 and 4,847,137.

The lens surface protection tapes were evaluated using the Deblock Test described in Example 6 except that a second set of blocked lens were deblocked after being allowed to set for 17 hours. The results are reported in Table 25b.

- W097tlO924 PCTrUS96/14668 Table 25b Run Tar et Thi~n~ Deblock Yalues after-Number Outer Film Tie Adhesive 1 hour 17 hours Layer' Layer Layer ~cm) (cm~
(mm) (mm~ (mm) 1 0.05080.0076 0.0762 8.4 10.9 2 0.05080.0076 0.0762 nal na 3 0.05080.0076 0.0762 10 2 13.5 4 0.05080.0076 0.0762 na na 0.05080.0076 0.0762 32.0 3~.3 6 0.05080.0076 0.0762 18.5 1~.5 7 0.05080.0076 0.0762 23.6 2~.4 "na" means not available.

Various modifications and alterations of this invention will be apparent to those skilled in the art without departing from the scope and spirit of this invention, and it should be understood that this invention is not limited to theillustrative embo~lim~nt~ set forth herein.

Claims (20)

What is claimed is:
1. An opthalmic lens block, comprising: a solidified mass of a thermoplastic blocking composition having a mean bending modulus of at least 69 MPa at 21 °C, the composition being solid at 21 °C and having a sufficiently low melting or softening point such that the composition may be placed adjacent to an ophthalmic lens blank while at its melting or softening point without damaging the lens blank.
2. An ophthalmic lens block according to claim 1, wherein the thermoplastic blocking composition is selected from the group consisting of polyesters, polyurethanes, ionomer resins of ethylene copolymers, polyester-polysiloxane block copolymers, segmented copolyesters and polyetheresters, ethylene vinyl acetate resins and copolymers, polycaprolactones and blends thereof.
3. An ophthalmic lens block, comprising: a solidified mass of a thermoplastic blocking composition comprising a homopolymer or copolymer of epsilon-caprolactone, the composition being solid at 21 °C and having a sufficiently low melting or softening point such that the composition may be placed adjacent to an ophthalmic lens blank while at its melting or softening point without damaging the lens blank.
4. An ophthalmic lens block according to any preceding claim, wherein the thermoplastic blocking composition comprises a blend of a high and a low molecular weight polycaprolactone.
5. An ophthalmic lens block according to any preceding claim, wherein the thermoplastic blocking composition further comprises a heat absorbing material.
6. An ophthalmic lens block according to any preceding claim, wherein the thermoplastic blocking composition has a melting or softening point between 45 and 75 °C.
7. An ophthalmic lens block according to any preceding claim, wherein the thermoplastic blocking composition further comprises a sufficient amount of a viscosity or performance modifier to enhance or adjust at least one of the viscosity of the heated composition and the flexural strength of the cooled composition.
8. An ophthalmic lens block according to any preceding claim, wherein the thermoplastic blocking composition further comprises a modifier selected from the group consisting of carboxylic acids of the general form CH3(CH2)nCOOH, where n is between about 10 and 16, straight chain monohydric alcohols of the general form CH3(CH2)nOH, where n is between about 11 and 19, branched chain monohydric alcohols having between 10 and 20 carbon atoms, polyethylene gylcols of the general form H(OCH2CH2)nOH, where n is between 20 and 185, and polyethylene glycol ethers of the general form R(OCH2CH2)nOR, where R is hydrogen or a straight-chain or branch alkyl group having between 1 and 10 carbon atoms and where n is between 17 and 116.
9. An ophthalmic lens block according to any preceding claim, wherein the thermoplastic blocking composition further comprises a modifier selected from the group consisting of 1-octadecanoic acid, 1-octadecanol, 1-hexadecanol, 1-tetradecanol, 1-dodecanol, polyethylene glycols having a weight average molecular weight between about 1,000 and 3,400, polyethylene glycol methyl ethers having a weight average molecular weight between about 1,000 and 3,400, and combinations thereof.
10. An ophthalmic lens block according to claims 7 to 9, wherein the modifier is present in an amount up to about 60 weight percent based on the total weight of the blocking composition.
11. An ophthalmic lens block according to any preceding claim, wherein the block comprises a preformed block defining a cavity with a lens blank, and wherein the cavity contains the solidified blocking composition.
12. An ophthalmic lens block according to any preceding claim, wherein the block comprises a preformed base block having a rear portion that is sized and adapted to fit the chuck of a lens processing machine, and a front portion having a negatively tapered peripheral edge and a curved front surface, wherein the front portion is adapted to mechanically retain the thermoplastic blocking composition to thereby form the lens block.
13. A composition, comprising:
a homopolymer or copolymer of epsilon-caprolactone; and a modifier selected from the group consisting of: carboxylic acids of the general form CH3(CH2)nCOOH, where n is preferably between about 10 and 16; straight chain monohydric alcohols of the general form CH3(CH2)nOH, where n is preferably between about 11 and 19; branched chain monohydric alcohols having between 10 and 20 carbon atoms; polyethylene gylcols of the general form H(OCH2CH2)nOH, where n is between 20 and 185; and polyethylene glycol ethers of the general form R(OCH2CH2)nOR, where R is typically hydrogen or a straight-chain or branch alkyl group having between 1 and 10 carbon atoms and where n is between 17 and 116; wherein the composition is solid at 21 °C and has a melting or softening point between 55 and 70 °C.
14. A preformed base block, comprising:
a rear portion that is sized and adapted to fit the chuck of a lens processing machine, and a front portion having a negatively tapered peripheral edge and a front surface, wherein the front portion is adapted to mechanically retain a thermoplastic blocking composition to form a lens block against a lens blank.
15. A method of holding an ophthalmic lens blank, comprising the steps of:
providing a thermoplastic lens blocking composition of claims 1 to 10;
heating the lens blocking composition to its melting or softening point;
providing a blocking material receiving cavity against the lens blank;
forming the ophthalmic lens blocking composition into the receiving cavity; and allowing the composition to solidify.
16. A method of holding an ophthalmic lens blank, comprising the steps of:
providing an ophthalmic lens block comprising a solidified mass of a thermoplastic blocking composition of claims 1 to 10;
heating the surface of the lens blocking composition to its melting or softening point;
positioning a lens blank against the softened surface of the lens blocking composition; and allowing the composition to resolidify.
17. A conformable tape for bonding a lens block comprising a thermoplastic lens blocking composition to an ophthalmic lens blank, comprising:
a polymer backing having a first major surface comprising a polymer composition having a polar moiety and a non-polar moiety; and a pressure-sensitive adhesive on a second major surface of said polymer backing.
18. The tape of Claim 17, wherein the backing comprises a blend of a polar polymer selected from the group consisting of polyurethane polymers and polycaprolactone polymers and a diluting polymer selected from the group consisting of polyethylene polymers and copolymers, ethylene-octene copolymers, maleic anhydride modified ethylene acrylate copolymers, and maleic anhydride modified low density polyethylenes.
19. The tape of Claim 18, wherein said blend comprises between 20 and 60%
polar polymer.
20. An ophthalmic lens blocking kit, comprising at least two of a thermoplastic blocking composition according to any preceding claim;
a preformed base block according to any preceding claim; and a lens blank tape according to any preceding claim.
CA002229801A 1995-09-18 1996-09-13 Thermoplastic lens blocking material Abandoned CA2229801A1 (en)

Applications Claiming Priority (2)

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US391895P 1995-09-18 1995-09-18
US60/003,918 1995-09-18

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US (5) US5919563A (en)
EP (1) EP0851800B1 (en)
JP (1) JPH11512480A (en)
AU (1) AU7360696A (en)
BR (1) BR9610536A (en)
CA (1) CA2229801A1 (en)
WO (1) WO1997010924A1 (en)

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Also Published As

Publication number Publication date
EP0851800A1 (en) 1998-07-08
BR9610536A (en) 1999-07-06
US6036313A (en) 2000-03-14
EP0851800B1 (en) 2002-06-05
US5827390A (en) 1998-10-27
JPH11512480A (en) 1999-10-26
US5916017A (en) 1999-06-29
AU7360696A (en) 1997-04-09
US5754269A (en) 1998-05-19
WO1997010924A1 (en) 1997-03-27
US5919563A (en) 1999-07-06

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