CA2151264A1 - Negative working, peel developable, single sheet color proofing system having a crosslined layer containing a polymer with phenolic moieties - Google Patents
Negative working, peel developable, single sheet color proofing system having a crosslined layer containing a polymer with phenolic moietiesInfo
- Publication number
- CA2151264A1 CA2151264A1 CA002151264A CA2151264A CA2151264A1 CA 2151264 A1 CA2151264 A1 CA 2151264A1 CA 002151264 A CA002151264 A CA 002151264A CA 2151264 A CA2151264 A CA 2151264A CA 2151264 A1 CA2151264 A1 CA 2151264A1
- Authority
- CA
- Canada
- Prior art keywords
- layer
- color
- photoadhering
- color layer
- present
- 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
Links
Classifications
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/004—Photosensitive materials
- G03F7/09—Photosensitive materials characterised by structural details, e.g. supports, auxiliary layers
- G03F7/095—Photosensitive materials characterised by structural details, e.g. supports, auxiliary layers having more than one photosensitive layer
- G03F7/0957—Photosensitive materials characterised by structural details, e.g. supports, auxiliary layers having more than one photosensitive layer with sensitive layers on both sides of the substrate
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F3/00—Colour separation; Correction of tonal value
- G03F3/10—Checking the colour or tonal value of separation negatives or positives
- G03F3/106—Checking the colour or tonal value of separation negatives or positives using non-macromolecular photopolymerisable compounds having carbon-to-carbon double bonds, other than silicon containing compounds
Abstract
In the present invention, one produces a negative-acting color proofing element comprising sequentially, a strippable cover sheet which is transparent to actinic radiation; a crosslinked layer containing a polymer having a phenolic groups; a color layer, containing a colorant, a polymeric binder, a polymerizable monomer and, optionally, a photoinitiator, a photoadhering layer, containing a linear photosensitive polymer containing ethylenically unsaturated, free-radical polymerizable groups and having a molecular weight greater than 3,000, a polymerizable monomer, and, optionally, a free radical photoinitiator; a thermoplastic adhesive layer; and a receiver sheet, at least one of the color layer and the photoadhering layer containing the photoiniator.
Description
WO 94117451 2 ~ ~ 1% 6 ~ PCT/US94/00705 Description Ne~ative Workin~e~ Peel Developable~
Single Sheet Color Proo~ln~ SYstem Havin~e a Crosslinked Layer Containing A Polymer With Phenolic Moieties s Back~round of the Invention The present invention relates to color proofing films, or more particularly to a negative working, peel-apart photosensitive element capable of producing negative images upon treatment with actinic radiation and peel 1 0 development.
In the graphic arts, it is desirable to produce a three or more color proof to assist in correcting a set of color separation films prior to using them to produce printing plates. The proof should reproduce the color quality that will be obtained during the printing process. The proof must be a consistent lS duplicate of the desired halftone image. Visual cY~min~tion of a color proof should show the color rendition to be expected from press printing using the color separations and any defects on the separations which might need to be altered before making the printing plates.
Color proofing sheets for multicolored printing can be made by using a 20 printing press or proof press. This requires that all of the actual printing steps be performed. Therefore, this conventional method of color proofing is costly and time cone-lminp Photoim~in~ processes can also be used to produce a color proo There are two general types of photoim~ging methods, namely the overlay type 25 and the single sheet type.
In the overlay type of color proofing method, an independent transpare~t plastic support is used for producing an image of each color separation film by applying a photosensitive solution of the corresponding color. A plurality of such supports carrying images of the corresponding colors are then 30 superimposed upon each other over a white sheet to produce a color proofing composite. The primary advantage of the overlay method is that proofs can be wo 94/17451 21 ~ I 2 ~ ll PCT/USg410070 made quickly and can serve as a progressive proof by combining any two or three colors in register. However, this type of color proofing method has the disadvantage that the superimposed plastic supports tend to darken the color proofing sheet. As a result, the impression of the color proofing composite S thus Frepared is vastly dirre-el~t from that of copies actually obtained with conventional printing presses and with proof presses. Examples of such overlay approaches are contained in U.S. Patents 3,136,637; 3,211,553; and 3,326,682.
In the single sheet type of color proofing method, a color proofing sheet is prepared by s~ccescively producing images of different colors from different color separation films on a single receiver sheet. This can be accomplished by sequentially applying colorants or colored, photosensitive layers to a single opaque support. This method more closely resembles the actual printing process and ~limin~te~ the color distortion inherent in the overlay system.
Examples of such single sheet approaches are contained in U.S. Patents 3,574,049; 3,671,236; 4,260,673; 4,366,223; 4,650,738; 4,656,114; and 4,659,642.
Various processes for producing single sheet color proofs of an image embodying thermal transfer and photopolymerization techniques are known, for example, from U.S. Patents 3,060,023; 3,060,024; 3,060,025; 3,481,736; and 3,607,264. In these processes, a photopolymerizable layer coated on a suitable support is imagewise exposed through a color separation film. The surface of the exposed layer is then pressed into contact with an image receptive surface of a separate element. At least one of the elements is heated to a temperature above the transfer temperature of the unexposed portions of the layer. The two elements are then St;~ ~led, whereby the thermally transferrable, unexposed, image areas of the composite transfer to the image receptive element. If the element is not precolored, the tacky unexposed image may now be selectively colored with a desired toner. The colored matter prefelenlially adheres to the clear unpolymerized material.
In U.S. Patent 3,721,557, a method for transferring colored images is shown which provides a stripping layer coated between a photosensitive WO94/17451 ~ PcrruS94 element and a support. When the photosensitive layer is exposed to actinic light and developed, the more soluble portions are selectively removed to produce a visible image. The image carrying support is pressed against an adhesive coated receptor member and the carrier support is subsequently S stripped to accomplish the transfer of the image. A fresh layer of adhesive must be applied to the receptor for each ~ubse~uent transfer.
U.S. Patent 4,596,757 provides a method for transferring images or solid colors which are subsequently imaged. The photosensitive material comprises a carrier support having sequentially disposed thereon a release layer; a colored,10 photopolymerizable layer; and an adhesive layer. The material can undergo exposure, l~min~tion to a temporary support, wet development, and then l~min~tion to a receptor sheet. Alternatively, the photosensitive material can be l~min~te~l to a receptor sheet, undergo exposure, and then wet processed. Both processes require development in an aqueous medium.
lS In U.S. Patent 4,489,154, a process is claimed which produces a single layer color proof without wet development. The photos~n~itive nnaterial comprises a strippable cover sheet; a colored photoadherent layer; a nonphotosensitive organic contiguous layer; and a sheet support. The material is exposed and peel developed. The positive or negative image is transferred to 20 a receiver base. A fresh layer of adhesive must be applied to the receptor for each subsequent transfer.
Summaly of the Invention In the present invention, one produces a negative-acting color proofing 25 element. The element sequentially comprises a strippable cover sheet which istransparent to actinic radiation; a crosslinked layer collt~ining a polymer having phenolic groups; a color layer, cont~ining a colorant, a polymeric binder, a polymerizable monomer and, optionally, a photoinitiator; a photoadhering layer, cont~ining a linear photosensitive polymer cont~ining ethylenically unsalu~ed~
30 free-radical polymerizable groups and having a molecular weight greater than 3,000, a polymerizable monomer, and, optionally, a free radical photoinitiator; a WO 94/17451 21 Sl ; PCT/US94/00705 thermoplastic a&esive layer; and a receiver sheet, at least one of the color layer and the photoadhering layer containing the photoinitiator. A single sheet,negative working color proofing film having improved image quality with very high resolution has been found by using the photosensitive polymer in the photoadhering layer of the articie of this invention.
It has been unexpectedly found that a negative image of very high resolution and low peel force can be obtained when a crosslinked layer of a phenolic resin is present between the strippable cover sheet and the color layer.
The article of the present invention provides consistent, high resolution negative images by a peel development process.
The present invention relates to a negative-acting, single sheet color proofing element which comprises, in order from top to bottom:
(i) a strippable, transparent cover sheet;
(ii) a cro~linked layer, which comprises a polymer having phenolic 1 5 groups;
(iii) a color layer, which comprises an organic binder, a polymerizable monomer, a colorant, and optionally, a photoinitiator wherein the binder is present in sufficient amount to bind the color layer components into a uniform film, wherein the optional photoinitiator, when present, is present in sufficient amount to initiate polymerization of the polymerizable monomer, wherein the polymerizable monomer is present in sufficient amount to provide image dirrer~ iation when the element is imagewise exposed to actinic radiation and wherein the colorant is present in an amount sufficient to uniformly color the color layer;
(iv ) a photoadhering layer, which comprises a photosensitive polymer having ethylenically u ls~lurated, photocro~link~kle groups and a molecular weight greater than 3,000, a polymerizable monomer having at least one ethylenically unsalu,~ed group and an optional photoinitiator, wherein the optional photoinitiator, when ~15126~
WO 94tl7451 PCr/US94/00705 present, is present in sufficient amount to initiate polymerization of the polymerizable monomer and the crosclinking of the photosensitive polymer and wherein at least one of either the color layer or the photoadhering layer contains a photoinitiator;
(v) a thermoplastic adhesive layer; and (vi) a support sheet.
The present invention also relates to a method for producing a negative image which comprises:
(A) providing a photosensitive color proofing element which comprises, in order from top to bottom:
(i) a strippable, transparent cover sheet;
(ii) a crosslinked layer, which comprises a polymer having phenolic groups;
(iii) a color layer layer, which comprises an organic binder, a polymerizable monomer, a colorant, and optionally, a photoinitiator wherein the binder is present in suf~lcient amount to bind the color layer col-Jpol~ents into a uniform film, wherein the optional photoinitiator, when present, is present in sufficient amount to initiate polymerization of the polymerizable monomer, wherein the polymerizable monomer is present in sufficient amount to provide image differentiation when the element is imagewise exposed to actinic radiation and wherein the colorant is present in an amount sufficient to uniformly color the color layer;
(iv) a photoadhering layer, which comprises a photosensitive polymer having ethylenically ullsalul~ed, photocroc.clink~ble groups and a molecular weight greater than 3,000, a polymeri7~ble monomer having at least one ethylenically unsalulaled group and an optional photoinitiator, wherein the optional photoinitiator, when present, is present in sufficient amount to initiate polymerization of the polymerizable monomer and the crocslinking of the WO 94tl7451 2 1 ~ 1 2 6 ~I - 6 - PCT/US94/00705 photosensitive polymer and wherein at least one of either the color layer or the photoadhering layer contains a photoinitiator;
(v) a thermoplastic adhesive layer;
(B) l~min~ting the photosensitive color proofing element to a receiver sheet;
5 (C) imagewise exposing the color layer and the photoadhering layer to actinic radiation through the transparent cover and crosslinked phenolic layer;
(D) peeling apart the receiver sheet and the transparent cover sheet, leaving exposed areas of the color layer attached to the receiver sheet via the photoadhering layer and adhesive layer and unexposed areas being removed with the cover sheet and the crosslinked phenolic layer, thereby forming a colored negative image on the receiver sheet; and (E) optionally repeating steps A) through D) at least once wherein another photosensitive element having at least one different colorant, is transferred via its photoadhering and adhesive layers to the negative image previously produced on the receiver sheet.
Detailed Desc~ ion of the Preferred Embodiment In the usual full color proofing guide, four distinct colored images are formed, namely magenta, cyan, yellow, and black. When the images are superimposed upon each other, a simulated full color reproduction results. As hereinbefore described, one begins the process of the present invention by preparing a photosensitive element which has a cover and carried thereon a polymerizable layer.
In the preferred embodiment, the cover sheets may be composed of any suitable flexible sheet material provided it is transparent to the actinic radiation for the color layer and adhesive layer. In the prere,led embodiment, it has a surface which is dimensionally stable when undergoing the herein specified treatment process. That is, it should have subst~nti~lly no change in dimensions under heating in the range of al.plu~illlately 60C to 120C during l~min~tion. One preferred material is polyethylene terephth~l~te. In the WO 94117451 2 1 5 1 2 6 ~ PCrlUS94/0070~
prere,.ed embodiment, it has a thickness of from about 1 to about 10 mils, a more plerel-ed thickness is from about 2 to about 5 mils and most preferably from about 2 to about 3 mils. Suitable films nonexclusively include Melinex 054, 504, 505, and 582 films available from ICI, and ~ost~rh~n 4400, 4500, 5 and 4540 films available from Hoechst Celanese Corporation. The surface of the support may be smooth or it may be provided with a matte ~exture as with Melinex 475 film. A smooth surface is preferred because a rough surface scatters the actinic radiation and thereby reduces the resolution capability of the element.
The phenolic layer is applied from a solvent coating composition to the cover sheet. Possible solvents include organic solvents as well as water. The phenolic polymer can be a novolak (cresol-formaldehyde resin), polyhydlo,~y~lyrene homo- and co-polymers, acrylic polymers cont~ining phenolic groups etc. Croselinking of the polymer can be achieved by the use 15 of, nonexclusively, polyisocyanates, melamine-formaldehyde resins, urea-formaldehyde resins, epoxy resins, aziridine resins, and heat, acrylic monomers and light, etc. The cros~linked phenolic layer should be insoluble in solvents used to coat the subsequent layer.
The color layer is applied from a solvent coating composition to the 20 clu~liked phenolic layer. Organic solvents are plefel,ed for the color layer because of the diverse solubility characteristics of the various components.
Typical solvents nonexclusively include methyl ethyl ketone, 2-methoxyethanol, 1-methoxy-2-propanol, 4-hydroxy-4-methyl-2-pentanone, tetrahydrofuran, diacetone alcohol, and gamma-butyrolactone.
The polymerizable monomers in the color layer and in the photoadhering layer preferably comprise addition polymerizable, non-gaseous (boiling temperature above 100C at normal atmospheric ~re~ule)~
ethylenically-unsaLu,~l~d compounds containing at least one and plerelably at least two termin~l ethylenically unsaLul~led groups, and being capable of forming a high molecular weight polymer by free radical initiated, chain propa~ting addition polymerization. The most preferred compounds are Wo 94/17451 ~ 1512 ~ ~ 8 - PCT/US94/00705 acrylate or methacrylate monomers as are well known in the art. Suitable polymerizable monomers nonexclusively include triethylene glycol dimethacrylate, tripropylene glycol diacrylate, tetraethylene glycol limeth~.rylate, diethylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol tlimeth~crylate, pentaerythritol tetraacrylate, trimethylol propane triacrylate, trimethylol propane trimethacrylate, di-pentaerythritol monohydroxypentaacrylate, pentaerythritol triacrylate, bisphenol-A-ethoxylate ~limeth~crylate, trimethylolpropane ethoxylate triacrylate, trimethylolpropane propoxylate triacrylate, and bisphenol A diepoxide dimethacrylate. The monomers in the color and photoadhering layers can be the same or different.
Free radical liberating photoinitiators used in the color layer and/or photoa&ering layer include any compound which liberate free radicals on stimulation by actinic radiation. :FIefel,ed photoinitiators nonexclusively include quinoxaline compounds as described in U.S. Patent 3,765,898; the vicinal polyketaldonyl compounds in U.S. Patent 2,367,660; the alpha-carbonyls in U.S. Patents 2,367,661 and 2,367,670; the acyloin ethers in U.S. Patent 2,448,828; the triarylimidazolyl dimers in U.S. Patent 3,479,185; the alpha-hydrocarbon-aubali~uled aromatic acyloins in U.S. Patent 2,722,512; polynuclear quinones in U.S. Patents 2,951,758 and 3,046,127; and s-tri~ines in U.S.
Patents 3,987,037 and 4,189,323. The most preferred photoinitiators include 2,3-di(4-methoxyphenyl)quinoxaline, 9-phenylacridine, 2-biphenyl-4,6-bis-trichloromethyl-5-triazine, bis(2,4,5-triphenyl)imidazole and its derivatives, bis-trichloromethyl-s-triazines, thioxanthones and acetophenones. The photoinitiatorused in the color and/or photoa&ering layer may be the same or dirre,eilt.
The color layer may also contain a binding resin which not only determines the hardness and/or flexibility of the coating but is also used to control the dry development. Binding resins found suitable for the color layer are polyvinyl ~cet~tec, styrene/maleic anhydride copolymers and their half esters; acrylic polymers and copolymers; polyamides; polyvinyl pyrrolidones;
cellulose and its derivatives; phenolic resins; and the like. The most ~ler~"ed binding resins are polyvinyl ~cet~tes and acetals, such as UCA~ resins ~1512~
9 : , available from Union Carbide, and polyvinyl formal, polyvinyl butyral and polyvinyl propional.
Dyes may be included in the color layer to spectrally sensitize the - photoinitiator, such as described in U.S. Patent 4,282,309 and 4,454,218, and European Patent Applications 0,179,448 and 0,211,615.
In the l,lGfe.led embodiment: 1) the dry color layer has a coating weight range of from about 0.1 to about 5 g/m2, preferably from about 0.4 to about 2 g/m2; 2) the crosslinked phenolic layer has a coating weight range of from about 0.1 to about 5 g/m2, preferably from about 0.4 to 1.0 g/m2.
In the practice of the present invention, the optional pho~oinitiator component is preferably present in the color layer in an amount ranging from approximately 0.01 to 20% based on the weight of the solids in the layer. A
,-ere,.ed range is from about 0.1 to 15%, more prGre,~bly from 1 to 10%.
In the practice of the present invention, the optional photoinitiator 15 co~ponent is l,lefe.~bly present in the photoa&ering layer in an amount ranging from a~ o~"--ately 1 to 40% based on the weight of the solids in the layer. A prefelled range is from about 2 to 30%, more l,-t;r~ bly from 5 to 20%.
Dyes and/or pigm~nt~ are included in the color layer to provide color to the image areas. Plefe.led colorants for this invention are pigment~ rather thandyes. Light fast colorants are l"Gre,led. The pigments are typically dispersed with an organic binder in an organic solvent or l~ UlG of organic solvents.
The pigm~nt~ may be organic or inorganic. They are ground to a small enough particle size to duplicate the particle size and color of equivalent inks. The median diameter is generally less than 1 micrometer.
Nonexclusive examples of colorants usable in the pr~ent invention are as follows: Permanent Yellow G (C.I. 21095), Permanent ~ellow GR (C.I.
21100), Permanent Yellow DHG (C.I. 21090), Permanent Rubine L6B (C.I.
15850:1), Permanent Pink F3B (C.I. 12433), Hostaperm Pink E (73915), Ho~l~e,lll Red Violet ER (C.I. 46500), Permanent Car~nine FBB (12485), Hosl~e.... Blue B2G (C.I. 74160), Hostaperm Blue A2R (C.I. 74160), and -Wo 94/17451 PCT/USg4/00705 ~
215~ 2~ lo Printex 25. Most of these are products of Hoechst AG. They can be used sep~alely or blended for a desired color.
Other ingredients which may be present in the color layer are thermal polymerization inhibitors, plasticizers, tackifiers, oligomers, residual solvents, S su~f~r~nts, inert fillers, antihalation agents, hydrogen atom donors, photoactivators, and optical bright~oning agents.
In a pl~felled embodiment of the present invention, the binder component is preferably present in the color layer in an amount sufficient to bind the components in a uniform mixture and a uniform film when it is coated 10 on a substrate. It is preferably present in an amount ranging from about 10 to about 90% based on the weight of the solids in the color layer. A more preferred range is from about 20 to about 80%.
In the pl~rt;lled embodiments, the polymerizable monomer is prest;lll.
1) in the color layer in an amount of from about 1 to about 60% by weight of 15 the total solids in the color layer, more prefe.~bly from about 5% to about 50%, and 2) in the photoadhering layer from 1 to about 50% by weight of the total solids in photoadhering layer, more preferably from about 10 to about 40%.
In the practice of the present invention, the colorant component is 20 plerelably present in an arnount sufficient to uniformly color the color layer. It is preferably present in an amount ranging from about S to about 50% based on the weight of the solids in the color layer. A more preferred range is from about 8 to about 40%.
A plasticizer may also be included in the color or photoadhering layer 25 of this invention to prevent coating brittleness and to keep the composition pliable if desired. Suitable plasticizers include dibutylphth~l~te, triarylphosph~te and ..ubsliluled analogs thereof and preferably dioctylphth~l~te.
Adhered to the color layer is the photoadhering layer. The photoadhering layer preferably comprises a photosensitive polymer, a 30 photoinitiator, and a polymerizable monomer, as hereinbefore deflned.
21512~
WO 94/174~1 - 1 1 - PCT/US94100705 To form the photoadhering layer, the components may be dissolved in a solvent or ,.,ixlu,e of solvents to facilitate application of the composition to the subs~ale. Suitable solvents for this purpose nonexclusively include water, tetrahydrofuran, n-butyl acetate, isobutyl isobutyrate, glycol ethers such as 5 propylene glycol monomethyl ether and methyl cellosolve, alcohols such as ethanol and n-propanol and ketones such as methyl ethyl ketone. In general, the solvent system is evaporated from the coating composition once it is applied to an appro~",ate substrate. However, some insignifican~ amount of solvent may remain as residue. In addition, the monomer from the 10 photoadhering layer tends to diffuse into the color layer during overcoating process, so one way of providing the color layer with the monomer is not to include it in the coating solution of the color layer, but let it migrate there from the photoadhering layer during coating and drying process, or during l~min~tion of the layers. This process of monomer migration via diffusion is known to 15 those skilled in the art of creating multilayer im~ging systems. According tothe present invention, it is i."po,l~,l that the monomer be present in the colorlayer when the element is exposed to actinic radiation, regardless of the way itbecame the part of the color layer.
In the preferred embodiment, the photoadhering layer has a coating 20 weight between ap~ k;...~tely 2 and 20 g/m2. The most prert;"~d weight is from about 4 to 10 g/m2.
The photo~flh~rin~ layer cont~in~ a polymerizable monomer and may optionally contain such other desired components as uv absorbers, ~nti~t~tic compositions, optical brighteners, inert fillers, therm~l polymerizable inhibitors, 25 residual solvents, surf~ct~nts, ~ntih~l~tion agents, hydrogen atom donors, tackifiers, and plasticizers. Suitable photosensitive polymers nonexclusively include: a urethane adduct of polyvinyl butyral or other acetal resins Gont~ining hydroxy groups and isocyanatoethyl methacrylate, or reaction product of hydroxy-cont~inin~ acetal resins with methacrylic anhydride, acrylic 30 acid, acryloyl chloride, etc. Acrylic polymers cnnt~ining hydroxy groups can also be used as ~ubs~ es with all the above (meth)acrylic groups-containing WO 94/17451 21512 ~ 4 12 - PCTN594/00705 reagents, as can polyvinyl alcohols and their copolymers, phenolic resins, etc.
Other reactive groups on polymers which can be (meth)acrylated nonexclusively include: amino, carboxyl, epoxy, etc. The (meth)acrylated polyvinyl acetal polymers are preferred. The photoa&ering layer may optionally contain a uv absorber such as Uvinul D-50 available from GAF. It may also contain a plasticizer such as Resoflex R-296, available from Cambridge Industries. It may also contain ~nti~t~tic compounds, such as Gafac and Gafstat available from GAF.
The therrnoplastic adhesive layer should be coated directly on the photoadhering layer. The coating weight should be 2-20g/m2, more preferred 5-15 g/m2, most preferred 6-10 g/m2. The adhesive layer should be coated from a solvent which does not disturb the photoadhering layer undemeath.
Water is the prefelled solvent. Examples of thermoplastic resins coatable out of water nonexclusively include Carboset acrylic resins, polyvinyl acetate/crotonic acid copolymers, polyvinyl pyrrolidone/polyvinyl acetate copolymers, polyvinyl acetate emulsions, styrene/maleic anhydride copolymers, urethane polymers, etc.
The adhesive layer should be transferable to a receiver sheet in a temperature range of from about 50C to about 180C, preferably 60C to 120C, more preferably 60C to 100C when l~min~ted with heat and pressure.
The plasticizer may be present in an amount of up to about 10% by weight and the uv absorber up to about 10% by weight.
Receiver sheets may comprise virtually any material which can withstand the l~min~ting and dry development processes. White plastic sheets, such as adhesion plell~aled polyester Melinex 3020 film available from ICI, are useful for this purpose. Plastic coated paper sheets, such as polyethylene coated paper available from Schoeller, may also be used. Other bases may include wood, glass, metal, paper and the like.
In place of direct overcoafing one can assemble the hereinbefore described photosensitive element by hot-l~min~ting the layers to each other, as is well known in the art.
21~12~
WO g4117451 PCTIUS94/00705 T.~min~tion may be conducted by putting the a&esive layer in contactwith the receiver sheet and then introducing the materials into the nip of a pair of heated l~min?fin~ rollers under suitable pressure. Suitable l~min~ting temper~lu~es usually range from ap,uloxi"-ately 60C to 120C, preferably from 5 70C to 100C. The element is then exposed by means well known in the art.
Such exposure may be con~cte~ by exposure to actinic radiation from a light source through a co~lve~llional halftone negative color sep~lion under vacuum frame conditions. Mercury vapor discharge lamps are p~erelled over metal halide lamps. Other radiation sources, such as carbon arc, pulsed xenon, and 10 lase~s, may also be used. Light absorbing filters may be used to reduce light scalle""g in t}t~ ~terials.
After e~pQsure, a negative image is anchored via the photoa&ering layer and a&esive layer on the lect;ivel sheet by stripping the Ll~s~,arent cover sheet from the receiver sheet at room temperature with a steady, continuous 15 motion. The plere,led peel angle relative to the peel direction is greater than 90. The d~l~min~tion leaves the photoexposed areas of the color layer attached to the photoa&ering layer, which in its entirety is attached to the receiver sheet via the a&esive layer on the receiver sheet. The nonexposed areas of the color layer remain on the phenolic layer on the cover sheet which 20 has been peeled apart from the ,~c~i~/el sheet. Thus, a negative image remains on the receiver sheet.
In order to attain a multicolored image, another photosensitive element comprising, in order, a transparent cover sheet, crosslinked phenolic layer, a color layer, a photoa&ering layer and an a&esive layer is l~min~ted onto the 25 first image on the receiver sheet, exposed and the second color is dry developed by peeling apart the receiver sheet from the cover sheet of the additional photos~n~itive element. The second negative image remains with its photosensitive a&esive layer with the first image. A third and a fourth image may be added in a manner similar to that used to produce the second image. In 30 the usual case, four colored layers are employed to produce a full color WO 94117451 2 1 ~ 1 2 6 ll PCr/US94/00705 reproduction of a desired image. These four colors are cyan, magenta, yellow and black.
A matte finish of the final image may be obtained by embossing the shiny, top surface of the image with a matte material, such as Melinex 377 film 5 available from ICI. This is done by l~min~ting together the final image and matte m7~teri~1 and peeling the matte material away.
The final four color proof may be given a uniform, blanket exposure to photoharden the exposed, colored areas on the receiver base. A protective layer may also be l~min~ted on top of the last dry developed layer.
The following nonlimiting examples serve to illustrate the invention.
Example 1 Photoadherin~ Layer Solution To prepare the polymer with ethylenically unsalul~led groups useful in photoadhering layer, 50 g of Butvar 79 polyvinyl butyral resin from ~m~ntQ
c;Q~ g free hydroxyl groups (10.5-13%, tAI,-e;ssed as % polyvinyl alcohol) was placed in 200 g of n-buty~l acetate with stirring, at room temperature. To this solution, there were added 20 g of isocyanatoethyl methacrylate (Monomer, Polymer & Dajac Laboratories, Inc.), along with 0.05 g of dibulylliil dilaurea~eas catalyst. The nliAIule was left stirring ovemight, and after that time no isocyanate band was seen in the IR spectrum of the polymer. Thus, a polymer COI-l ~;lling methacrylate groups was created.
To 10 g of the above stock solution, there were added 0.38 g of Sartomer 399 Dipentae,ylh,ilol pentaacrylate (available from the Sartomer Co.), as monomer, and 0.1 g of 2-biphenyl-4,6-bis-trichloromethyl-s-triazine as initiator, completing the photoadhering layer formulation.
Phenolic Layer Solution 1. Methyl Ethyl Ketone (MEK) - 47 g 2. Dowanol PM - 47 g 3. Poly-p-hyd~oAy~lylene (6,200 MW, available from Hoechst Cel~n~se wo g41l74sl 2 1 ~ 1 2 6 ~ PCT/US94/00705 Corporation) - 3 g 4. Melamine-formaldehyde resin (Cymel 303, Cyanamid) - lg 5. p-Toluene sulfonic acid - 0.2 g This solution was coated on Melinex 505, 2 mil polyester available from ICI to 5 coating weight of .5 g/m2. The layer subsequently crosslinked upon drying in the oven at 110C for 2 minutes. Cro~clinking was verified by MEK rubs.
Color Layer Solution 1. Tetrahydrofuran - 21.7 g 2. Dowanol PM - 43.42 g 3. Diacetone alcohol - 16.18 g 4. Urethane adduct of 1 mole of trimethylhexamethylene diisocyanate with 2 moles of 2-hydroxyethyl-4,6-bis-acryloxyethyl isocyanurate (Aronix M-215, Mitsui) - 3.38 g 5. 2-biphenyl-4,6-bis-trichloromethyl-s-triazine - 0.84 g 6. Magenta Formvar Dispersion (19.8% solution) (The Dispersion consists, in percent by weight, of: 80.2% gamma-butyrolactone, 9.0 FORMVAR
12/85 polyvinyl formal resin ~available from ~on~nto Co.]) and 10.8%
Permanent C~rrnine FB) - 14.48 g 20 The color coat solution was coated on the crosslinked phenolic layer on the cover sheet and dried. The coating weight was 0.8 g/m2. The color coat was then overcoated with the above photoadhering layer solution with a Meyer rod #24 and dried. The coating weight was 6.8 g/m2.
The adhesive solution was Carboset XL-37 aqueous acrylic dispersion 25 (available from B.F. Goodrich). It was coated on the photoadhering layer with a Meyer rod #15 and dried. The coating weight was 6 g/m2.
The receiver base was Pres~m~teh Commercial Receiver Base, available from Hoechst Celanese Corporation.
The above-described photosensitive element was l~min~te(l to the above 30 receiver base using heat and p~ u,e. The thusly prepared composite was imagewise exposed to actinic radiation through the transparent cover sheet WO 94/17451 PCT/US94/0070~ --21512~ - 16-using a UGRA target for 15 seconds in a Berkey-Ascor exposure unit. Peeling away the cover sheet resulted in exposed areas of the color coat staying on the photoadhering layer, which in its entirety remained attached to the receiver sheet via the adhesive layer, while unexposed areas of the color coat were removed together with the cover sheet and the entire phenolic layer. The thusly obtained negative m~gent~ image anchored to the base via the adhesive showed dot reproduction of 3-97% at 150 lines/inch, and very low peel force.
Exposing the element for 30 and 45 seconds did not increase the peel force noticeably.
Col"~ ive Example 2 Example 1 was repeated, but the element did not contain the crosslinked phenolic layer. At 15 second exposure, the peel force of this element was comparable to that of the element of Example 1, but at 30 and 45 second exposure the peel force of the element of Example 2 increased sharply causing unwanted de-l~min~tion from the receiver sheet during peel development.
Example 3 Phenolic Layer Solution 1. Methyl Ethyl Ketone - 47 g 2. Dowanol PM - 47 g 3. Cresol/formaldehyde Novolak (S-Resin, available from Hoechst Celanese Corp.) - 3 g 4. Mel~mine/formaldehyde resin (Cymel 303, Cyanamid) - 1 g 5. p-Toluene sulfonic acid - 0.2 g The above solution was used in place of phenolic layer solution from Example 1, and the procedure was repeated. 20 second exposure and peel development afforded an image with 3-97% resolution at 150 lines/inch screen and low peel force, which did not increase appreciably with exposure.
21~1264 WO 94/17451 PCTnUS94/00705 Example 4 Phenolic Layer Solution 1. Methyl Ethyl Ketone - 47 g 2. Dowanol PM - 47 g 3. Poly-p-hyd.u"y~lyl~.le (20,000 MW, available from Hoechst Cel~nese Corp.) - 3g 4. Desmodur N-3300 (Polyisocyanate, Miles) - 1 g This solution wac used in place of the phenolic layer solution in Example 3.
Crosslinking was verified by MEK rubs of the phenolic layer after dlying, and 10 the coating procedures were repeated. After 20 second exposure and peel development the el~-Tne-nt showed 2-97% resolution and low peel force.
Comparative Example 5 This example illu~llales the necessity of crosclinking of the phenolic 15 layer prior to coating of sul?se~ t layers.
Phenolic Layer Solution 1. Methyl Ethyl Ketone - 47 g 2. Dowanol PM - 47 g 3. Poly-p-hyd,u~y:~lyltille (20,000 MW, available from Hoechst Cel~nese Corp.) - 3 g This solution was coated on 2 mil Melinex 505 polyester and dried. In the ~bsPnce of suitable crosclinker, the layer was easily ~tt~cl~ec~ by MEK.
Repeating the coating procedures of Example 1 on this sample, exposure for 45 25 seconds to light and peel development resulted in undesireably high peel forces.
Example 6 This example shows a pre~ alion of a four-color proof using the 30 present invention. The formulations for the color layers include the following ingredients in parts by weight.
WO 94/17451 ' ' ~ Pcr/uS94/00705 2 ~ 2 6 l~ . - 18 -Ingredient - Color Layer Cvan YellowMa~enta Black Tetrahyd,ufu,~, 200 200 200 200 4-hydroxy-4-methyl pentanone 150 150 150 150 1-methoxy-2-propanol 444 465 489 490 Formvar 12/85 resin 12 13 15 18 Sartomer 369 (Sartomer Co, Hydroxyethyl isocyanurate triacrylate monomer) 10 12 16 15 Hostaperm B2G 14 Permanent Yellow GR - 14 Permanent Red FBB - - 24 Printex 25 - - - 24 15 The pigments were dispersed in some of the Formvar 12/85 and solvents. The color solutions were coated on the cros~linked phenolic layer from Example 1 with a Meyer rod #12 and dried. The photoadhering solution from Example 1 was overcoated on each color layer with a Meyer rod #24, and dried, as was the Carboset XL-37 adhesive solution. The receiver base for the four-color 20 proof was Pres~m~tçh Commercial Receiver Base. The first photosensitive element, magenta, was l~min~ted to the receiver base by using heat and ple~,~,ule7 and imagewise exposed to actinic radiation through the transparent polyester cover sheet for 10 seconds. Upon peeling away the polyester cover sheet, the unexposed areas of the color layer were removed along with it, while 25 the exposed areas of the color layer remained anchored to the base via the photoadhering layer and the adhesive layer. Thus, a negative image was created on the receiver base, while a positive image was removed together with the transparent carrier sheet. The second photosensitive element, yellow, was in turn l~min~tecl to the previously created negative magenta image. Upon 30 imagewise exposure to actinic light via a target in registration with the previous image, and peeling away the polymer sheet, the yellow negative image was WO 94/17451 ~ 1 5 1 ~ ~ 4 PCT/US94/00705 created, attached to the previous image via the photosensitive adhesive.
Repeating the above procedure for the rem~ining two colors resulted in a high quality negative color proof.
S Conlpa~ e Example 7 This example describes the results when polymer other than one cont~inin~ phenolic groups is used in the crosslinked top layer.
Top Layer Solution 10 1. Methyl Ethyl Ketone - 47 g 2. Dowanol PM - 47 g 3. Carboset 526 (Acrylic Polymer, available from BF Goodrich) - 3 g 4. Cymel 303 - 1 g 5. p-Toluenesulfonic acid - 0.5 g 15 The top layer was coated on 2 mil Melinex 505 polyester and cros~linked during drying at 120C for 2 minutes The procedure from Example 1 was then followed. Exposures at 30 and 45 seconds resulted in high peel force and del~min~.on.
Example 8 This example illu~ tes the use of a methacrylated acrylic polymer in the photoa&ering layer.
15 grams of a copolymer of isobutyl meth~(rylate and hydroxyethyl methacrylate (75/25) were dissolved in 100 g of methyl ethyl ketone.
Methacrylic anhydride (4.5 g) was added, followed by 0.5 g of p-dimethylamino pyridine as catalyst. The mi~lu~e was refluxed for 6 hours, cooled, and the polymer was plt;ci~ ldd in water and dried. IR spectrum of the polymer showed the presence of unpolymerized methacrylate groups.
This polymer was used in place of the urethane adduct of Butvar B 79 and isocyanatoethyl methacrylate in Example 1. Following the procedure of WO 94/17451 2 1 ~ 1 2 ~ 4 PCr/US94/00705 ~
Example 1 resulted in image with resolution of 5-95% on 150 lines/inch screen.
Peel development of elements exposed longer did not reveal high peel forces.
Example 9 S This example illu~llates the ~ ion of the element of the present invention by l~min~tion rather than direct overcoating of all the layers.
The phenolic layer solution from Example 1 was coated on 2 mil Melinex 505 substrate and crosslinked. This was overcoated by the color layer solution from Example 1 and dried. On a separale sheet of polyester, 3 mil Melinex 516 available from ICI, was coated photoadhering layer solution from Example 1 and dried. This was overcoated with the adhesive layer solution from Example 1 dried.
The element on Melinex 516 was then l~min~ted to a receiver sheet identical to that used in Example 1 and the Melinex 516 polyester sheet was peeled off. This created an element, con~i~ting of, from top to bottom:
photoadhering layer, adhesive layer, and receiver sheet. To this element, there was l~min~tefl color layer in contact with the photoadhering layer, the element on Melinex 505. The newly created multilayer element was exposed to actinic radiation analogously to Example 1 and peel-developed. An image with resolution of 3-97% was created, and longer exposures did not increase the peel forces.
Example 10 This example illu~llates incorporating a monomer in the color layer by controlled diffusion of the monomer from the photoadhering layer.
Color Layer Solution:
1. Tetrahy.lrorul~l - 21.7 g 2. Dowanol PM - 43.42 g 3. Diacetone alcohol - 16.18 g 4. Magenta Formvar Dispersion (19.8% solution) (The Dispersion consists, in percent by weight, of: 80.2% garnma-butyrolactone, 9.0 FORMVAR
12/85 resin and 10.8% Permanent Carmine FB) - 14.48 g 5. Irgacure 369 (2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one initiator, Ciba-Geigy) - 0.5 g This color solution was coated on the crosslinked phenolic layer from Exarnple 1 with Meyer rod #10 and dried. Since it does not contain a monomer, it is not expected to be photopolymerizable. A controlled experiment was performed, in which the above element was imagewise irradiated for 10 minutes with actinic light, and thelearler rubbed with a pad soaked in ethyl acetate. The color coating readily dissolved, indicating that no photopolymerization took place, asexpected.
Photoadherin~ Layer Solution 1. Stock Solution from Example 1 - 10 g 2. Sartomer 399 monomer - 0.38 g 3. Irgacure 369 Photoinitiator - 0.01 g This solution was overcoated on above-described color element with a Meyer rod #24 and dried to give the photoadhering layer. This layer was then peeled off the color layer and discarded. Now the color layer was imagewise exposed to actinic light for 10 minutes and rubbed with a pad soaked in ethyl acetate.
The exposed areas of the color layer were insoluble due to photopolymerization, while the unexposed areas dissolved as before. IR
showed the presence of acrylic monomer in these areas. This monomer 2~ diffused into the color layer from the photoadhering layer.
Another element was prepared as described above. The photoadhering layer was not peeled off, but overcoated with an adhesive layer, as described inExample 1. T.~nnination to receiver sheet, imagewise exposure and peel development of the element gave an image with 3-97% resolution.
Diffusion of liquid monomers between layers in multilayer elements is known in the art. Thus, in order to provide the color layer with a monomer, WO 94117451 Pcrtuss4/00705 21 ~1 2 6 ll - 22 -one can either include the monomer in the color solution in the first place, or not include it, but let it diffuse from the photoadhering layer, or both include it, and let the additional monomer diffuse from the photoadhering layer into the color layer. The final element, thus, comprises at least one monomer in both 5 color and photoadhering layers
Single Sheet Color Proo~ln~ SYstem Havin~e a Crosslinked Layer Containing A Polymer With Phenolic Moieties s Back~round of the Invention The present invention relates to color proofing films, or more particularly to a negative working, peel-apart photosensitive element capable of producing negative images upon treatment with actinic radiation and peel 1 0 development.
In the graphic arts, it is desirable to produce a three or more color proof to assist in correcting a set of color separation films prior to using them to produce printing plates. The proof should reproduce the color quality that will be obtained during the printing process. The proof must be a consistent lS duplicate of the desired halftone image. Visual cY~min~tion of a color proof should show the color rendition to be expected from press printing using the color separations and any defects on the separations which might need to be altered before making the printing plates.
Color proofing sheets for multicolored printing can be made by using a 20 printing press or proof press. This requires that all of the actual printing steps be performed. Therefore, this conventional method of color proofing is costly and time cone-lminp Photoim~in~ processes can also be used to produce a color proo There are two general types of photoim~ging methods, namely the overlay type 25 and the single sheet type.
In the overlay type of color proofing method, an independent transpare~t plastic support is used for producing an image of each color separation film by applying a photosensitive solution of the corresponding color. A plurality of such supports carrying images of the corresponding colors are then 30 superimposed upon each other over a white sheet to produce a color proofing composite. The primary advantage of the overlay method is that proofs can be wo 94/17451 21 ~ I 2 ~ ll PCT/USg410070 made quickly and can serve as a progressive proof by combining any two or three colors in register. However, this type of color proofing method has the disadvantage that the superimposed plastic supports tend to darken the color proofing sheet. As a result, the impression of the color proofing composite S thus Frepared is vastly dirre-el~t from that of copies actually obtained with conventional printing presses and with proof presses. Examples of such overlay approaches are contained in U.S. Patents 3,136,637; 3,211,553; and 3,326,682.
In the single sheet type of color proofing method, a color proofing sheet is prepared by s~ccescively producing images of different colors from different color separation films on a single receiver sheet. This can be accomplished by sequentially applying colorants or colored, photosensitive layers to a single opaque support. This method more closely resembles the actual printing process and ~limin~te~ the color distortion inherent in the overlay system.
Examples of such single sheet approaches are contained in U.S. Patents 3,574,049; 3,671,236; 4,260,673; 4,366,223; 4,650,738; 4,656,114; and 4,659,642.
Various processes for producing single sheet color proofs of an image embodying thermal transfer and photopolymerization techniques are known, for example, from U.S. Patents 3,060,023; 3,060,024; 3,060,025; 3,481,736; and 3,607,264. In these processes, a photopolymerizable layer coated on a suitable support is imagewise exposed through a color separation film. The surface of the exposed layer is then pressed into contact with an image receptive surface of a separate element. At least one of the elements is heated to a temperature above the transfer temperature of the unexposed portions of the layer. The two elements are then St;~ ~led, whereby the thermally transferrable, unexposed, image areas of the composite transfer to the image receptive element. If the element is not precolored, the tacky unexposed image may now be selectively colored with a desired toner. The colored matter prefelenlially adheres to the clear unpolymerized material.
In U.S. Patent 3,721,557, a method for transferring colored images is shown which provides a stripping layer coated between a photosensitive WO94/17451 ~ PcrruS94 element and a support. When the photosensitive layer is exposed to actinic light and developed, the more soluble portions are selectively removed to produce a visible image. The image carrying support is pressed against an adhesive coated receptor member and the carrier support is subsequently S stripped to accomplish the transfer of the image. A fresh layer of adhesive must be applied to the receptor for each ~ubse~uent transfer.
U.S. Patent 4,596,757 provides a method for transferring images or solid colors which are subsequently imaged. The photosensitive material comprises a carrier support having sequentially disposed thereon a release layer; a colored,10 photopolymerizable layer; and an adhesive layer. The material can undergo exposure, l~min~tion to a temporary support, wet development, and then l~min~tion to a receptor sheet. Alternatively, the photosensitive material can be l~min~te~l to a receptor sheet, undergo exposure, and then wet processed. Both processes require development in an aqueous medium.
lS In U.S. Patent 4,489,154, a process is claimed which produces a single layer color proof without wet development. The photos~n~itive nnaterial comprises a strippable cover sheet; a colored photoadherent layer; a nonphotosensitive organic contiguous layer; and a sheet support. The material is exposed and peel developed. The positive or negative image is transferred to 20 a receiver base. A fresh layer of adhesive must be applied to the receptor for each subsequent transfer.
Summaly of the Invention In the present invention, one produces a negative-acting color proofing 25 element. The element sequentially comprises a strippable cover sheet which istransparent to actinic radiation; a crosslinked layer collt~ining a polymer having phenolic groups; a color layer, cont~ining a colorant, a polymeric binder, a polymerizable monomer and, optionally, a photoinitiator; a photoadhering layer, cont~ining a linear photosensitive polymer cont~ining ethylenically unsalu~ed~
30 free-radical polymerizable groups and having a molecular weight greater than 3,000, a polymerizable monomer, and, optionally, a free radical photoinitiator; a WO 94/17451 21 Sl ; PCT/US94/00705 thermoplastic a&esive layer; and a receiver sheet, at least one of the color layer and the photoadhering layer containing the photoinitiator. A single sheet,negative working color proofing film having improved image quality with very high resolution has been found by using the photosensitive polymer in the photoadhering layer of the articie of this invention.
It has been unexpectedly found that a negative image of very high resolution and low peel force can be obtained when a crosslinked layer of a phenolic resin is present between the strippable cover sheet and the color layer.
The article of the present invention provides consistent, high resolution negative images by a peel development process.
The present invention relates to a negative-acting, single sheet color proofing element which comprises, in order from top to bottom:
(i) a strippable, transparent cover sheet;
(ii) a cro~linked layer, which comprises a polymer having phenolic 1 5 groups;
(iii) a color layer, which comprises an organic binder, a polymerizable monomer, a colorant, and optionally, a photoinitiator wherein the binder is present in sufficient amount to bind the color layer components into a uniform film, wherein the optional photoinitiator, when present, is present in sufficient amount to initiate polymerization of the polymerizable monomer, wherein the polymerizable monomer is present in sufficient amount to provide image dirrer~ iation when the element is imagewise exposed to actinic radiation and wherein the colorant is present in an amount sufficient to uniformly color the color layer;
(iv ) a photoadhering layer, which comprises a photosensitive polymer having ethylenically u ls~lurated, photocro~link~kle groups and a molecular weight greater than 3,000, a polymerizable monomer having at least one ethylenically unsalu,~ed group and an optional photoinitiator, wherein the optional photoinitiator, when ~15126~
WO 94tl7451 PCr/US94/00705 present, is present in sufficient amount to initiate polymerization of the polymerizable monomer and the crosclinking of the photosensitive polymer and wherein at least one of either the color layer or the photoadhering layer contains a photoinitiator;
(v) a thermoplastic adhesive layer; and (vi) a support sheet.
The present invention also relates to a method for producing a negative image which comprises:
(A) providing a photosensitive color proofing element which comprises, in order from top to bottom:
(i) a strippable, transparent cover sheet;
(ii) a crosslinked layer, which comprises a polymer having phenolic groups;
(iii) a color layer layer, which comprises an organic binder, a polymerizable monomer, a colorant, and optionally, a photoinitiator wherein the binder is present in suf~lcient amount to bind the color layer col-Jpol~ents into a uniform film, wherein the optional photoinitiator, when present, is present in sufficient amount to initiate polymerization of the polymerizable monomer, wherein the polymerizable monomer is present in sufficient amount to provide image differentiation when the element is imagewise exposed to actinic radiation and wherein the colorant is present in an amount sufficient to uniformly color the color layer;
(iv) a photoadhering layer, which comprises a photosensitive polymer having ethylenically ullsalul~ed, photocroc.clink~ble groups and a molecular weight greater than 3,000, a polymeri7~ble monomer having at least one ethylenically unsalulaled group and an optional photoinitiator, wherein the optional photoinitiator, when present, is present in sufficient amount to initiate polymerization of the polymerizable monomer and the crocslinking of the WO 94tl7451 2 1 ~ 1 2 6 ~I - 6 - PCT/US94/00705 photosensitive polymer and wherein at least one of either the color layer or the photoadhering layer contains a photoinitiator;
(v) a thermoplastic adhesive layer;
(B) l~min~ting the photosensitive color proofing element to a receiver sheet;
5 (C) imagewise exposing the color layer and the photoadhering layer to actinic radiation through the transparent cover and crosslinked phenolic layer;
(D) peeling apart the receiver sheet and the transparent cover sheet, leaving exposed areas of the color layer attached to the receiver sheet via the photoadhering layer and adhesive layer and unexposed areas being removed with the cover sheet and the crosslinked phenolic layer, thereby forming a colored negative image on the receiver sheet; and (E) optionally repeating steps A) through D) at least once wherein another photosensitive element having at least one different colorant, is transferred via its photoadhering and adhesive layers to the negative image previously produced on the receiver sheet.
Detailed Desc~ ion of the Preferred Embodiment In the usual full color proofing guide, four distinct colored images are formed, namely magenta, cyan, yellow, and black. When the images are superimposed upon each other, a simulated full color reproduction results. As hereinbefore described, one begins the process of the present invention by preparing a photosensitive element which has a cover and carried thereon a polymerizable layer.
In the preferred embodiment, the cover sheets may be composed of any suitable flexible sheet material provided it is transparent to the actinic radiation for the color layer and adhesive layer. In the prere,led embodiment, it has a surface which is dimensionally stable when undergoing the herein specified treatment process. That is, it should have subst~nti~lly no change in dimensions under heating in the range of al.plu~illlately 60C to 120C during l~min~tion. One preferred material is polyethylene terephth~l~te. In the WO 94117451 2 1 5 1 2 6 ~ PCrlUS94/0070~
prere,.ed embodiment, it has a thickness of from about 1 to about 10 mils, a more plerel-ed thickness is from about 2 to about 5 mils and most preferably from about 2 to about 3 mils. Suitable films nonexclusively include Melinex 054, 504, 505, and 582 films available from ICI, and ~ost~rh~n 4400, 4500, 5 and 4540 films available from Hoechst Celanese Corporation. The surface of the support may be smooth or it may be provided with a matte ~exture as with Melinex 475 film. A smooth surface is preferred because a rough surface scatters the actinic radiation and thereby reduces the resolution capability of the element.
The phenolic layer is applied from a solvent coating composition to the cover sheet. Possible solvents include organic solvents as well as water. The phenolic polymer can be a novolak (cresol-formaldehyde resin), polyhydlo,~y~lyrene homo- and co-polymers, acrylic polymers cont~ining phenolic groups etc. Croselinking of the polymer can be achieved by the use 15 of, nonexclusively, polyisocyanates, melamine-formaldehyde resins, urea-formaldehyde resins, epoxy resins, aziridine resins, and heat, acrylic monomers and light, etc. The cros~linked phenolic layer should be insoluble in solvents used to coat the subsequent layer.
The color layer is applied from a solvent coating composition to the 20 clu~liked phenolic layer. Organic solvents are plefel,ed for the color layer because of the diverse solubility characteristics of the various components.
Typical solvents nonexclusively include methyl ethyl ketone, 2-methoxyethanol, 1-methoxy-2-propanol, 4-hydroxy-4-methyl-2-pentanone, tetrahydrofuran, diacetone alcohol, and gamma-butyrolactone.
The polymerizable monomers in the color layer and in the photoadhering layer preferably comprise addition polymerizable, non-gaseous (boiling temperature above 100C at normal atmospheric ~re~ule)~
ethylenically-unsaLu,~l~d compounds containing at least one and plerelably at least two termin~l ethylenically unsaLul~led groups, and being capable of forming a high molecular weight polymer by free radical initiated, chain propa~ting addition polymerization. The most preferred compounds are Wo 94/17451 ~ 1512 ~ ~ 8 - PCT/US94/00705 acrylate or methacrylate monomers as are well known in the art. Suitable polymerizable monomers nonexclusively include triethylene glycol dimethacrylate, tripropylene glycol diacrylate, tetraethylene glycol limeth~.rylate, diethylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol tlimeth~crylate, pentaerythritol tetraacrylate, trimethylol propane triacrylate, trimethylol propane trimethacrylate, di-pentaerythritol monohydroxypentaacrylate, pentaerythritol triacrylate, bisphenol-A-ethoxylate ~limeth~crylate, trimethylolpropane ethoxylate triacrylate, trimethylolpropane propoxylate triacrylate, and bisphenol A diepoxide dimethacrylate. The monomers in the color and photoadhering layers can be the same or different.
Free radical liberating photoinitiators used in the color layer and/or photoa&ering layer include any compound which liberate free radicals on stimulation by actinic radiation. :FIefel,ed photoinitiators nonexclusively include quinoxaline compounds as described in U.S. Patent 3,765,898; the vicinal polyketaldonyl compounds in U.S. Patent 2,367,660; the alpha-carbonyls in U.S. Patents 2,367,661 and 2,367,670; the acyloin ethers in U.S. Patent 2,448,828; the triarylimidazolyl dimers in U.S. Patent 3,479,185; the alpha-hydrocarbon-aubali~uled aromatic acyloins in U.S. Patent 2,722,512; polynuclear quinones in U.S. Patents 2,951,758 and 3,046,127; and s-tri~ines in U.S.
Patents 3,987,037 and 4,189,323. The most preferred photoinitiators include 2,3-di(4-methoxyphenyl)quinoxaline, 9-phenylacridine, 2-biphenyl-4,6-bis-trichloromethyl-5-triazine, bis(2,4,5-triphenyl)imidazole and its derivatives, bis-trichloromethyl-s-triazines, thioxanthones and acetophenones. The photoinitiatorused in the color and/or photoa&ering layer may be the same or dirre,eilt.
The color layer may also contain a binding resin which not only determines the hardness and/or flexibility of the coating but is also used to control the dry development. Binding resins found suitable for the color layer are polyvinyl ~cet~tec, styrene/maleic anhydride copolymers and their half esters; acrylic polymers and copolymers; polyamides; polyvinyl pyrrolidones;
cellulose and its derivatives; phenolic resins; and the like. The most ~ler~"ed binding resins are polyvinyl ~cet~tes and acetals, such as UCA~ resins ~1512~
9 : , available from Union Carbide, and polyvinyl formal, polyvinyl butyral and polyvinyl propional.
Dyes may be included in the color layer to spectrally sensitize the - photoinitiator, such as described in U.S. Patent 4,282,309 and 4,454,218, and European Patent Applications 0,179,448 and 0,211,615.
In the l,lGfe.led embodiment: 1) the dry color layer has a coating weight range of from about 0.1 to about 5 g/m2, preferably from about 0.4 to about 2 g/m2; 2) the crosslinked phenolic layer has a coating weight range of from about 0.1 to about 5 g/m2, preferably from about 0.4 to 1.0 g/m2.
In the practice of the present invention, the optional pho~oinitiator component is preferably present in the color layer in an amount ranging from approximately 0.01 to 20% based on the weight of the solids in the layer. A
,-ere,.ed range is from about 0.1 to 15%, more prGre,~bly from 1 to 10%.
In the practice of the present invention, the optional photoinitiator 15 co~ponent is l,lefe.~bly present in the photoa&ering layer in an amount ranging from a~ o~"--ately 1 to 40% based on the weight of the solids in the layer. A prefelled range is from about 2 to 30%, more l,-t;r~ bly from 5 to 20%.
Dyes and/or pigm~nt~ are included in the color layer to provide color to the image areas. Plefe.led colorants for this invention are pigment~ rather thandyes. Light fast colorants are l"Gre,led. The pigments are typically dispersed with an organic binder in an organic solvent or l~ UlG of organic solvents.
The pigm~nt~ may be organic or inorganic. They are ground to a small enough particle size to duplicate the particle size and color of equivalent inks. The median diameter is generally less than 1 micrometer.
Nonexclusive examples of colorants usable in the pr~ent invention are as follows: Permanent Yellow G (C.I. 21095), Permanent ~ellow GR (C.I.
21100), Permanent Yellow DHG (C.I. 21090), Permanent Rubine L6B (C.I.
15850:1), Permanent Pink F3B (C.I. 12433), Hostaperm Pink E (73915), Ho~l~e,lll Red Violet ER (C.I. 46500), Permanent Car~nine FBB (12485), Hosl~e.... Blue B2G (C.I. 74160), Hostaperm Blue A2R (C.I. 74160), and -Wo 94/17451 PCT/USg4/00705 ~
215~ 2~ lo Printex 25. Most of these are products of Hoechst AG. They can be used sep~alely or blended for a desired color.
Other ingredients which may be present in the color layer are thermal polymerization inhibitors, plasticizers, tackifiers, oligomers, residual solvents, S su~f~r~nts, inert fillers, antihalation agents, hydrogen atom donors, photoactivators, and optical bright~oning agents.
In a pl~felled embodiment of the present invention, the binder component is preferably present in the color layer in an amount sufficient to bind the components in a uniform mixture and a uniform film when it is coated 10 on a substrate. It is preferably present in an amount ranging from about 10 to about 90% based on the weight of the solids in the color layer. A more preferred range is from about 20 to about 80%.
In the pl~rt;lled embodiments, the polymerizable monomer is prest;lll.
1) in the color layer in an amount of from about 1 to about 60% by weight of 15 the total solids in the color layer, more prefe.~bly from about 5% to about 50%, and 2) in the photoadhering layer from 1 to about 50% by weight of the total solids in photoadhering layer, more preferably from about 10 to about 40%.
In the practice of the present invention, the colorant component is 20 plerelably present in an arnount sufficient to uniformly color the color layer. It is preferably present in an amount ranging from about S to about 50% based on the weight of the solids in the color layer. A more preferred range is from about 8 to about 40%.
A plasticizer may also be included in the color or photoadhering layer 25 of this invention to prevent coating brittleness and to keep the composition pliable if desired. Suitable plasticizers include dibutylphth~l~te, triarylphosph~te and ..ubsliluled analogs thereof and preferably dioctylphth~l~te.
Adhered to the color layer is the photoadhering layer. The photoadhering layer preferably comprises a photosensitive polymer, a 30 photoinitiator, and a polymerizable monomer, as hereinbefore deflned.
21512~
WO 94/174~1 - 1 1 - PCT/US94100705 To form the photoadhering layer, the components may be dissolved in a solvent or ,.,ixlu,e of solvents to facilitate application of the composition to the subs~ale. Suitable solvents for this purpose nonexclusively include water, tetrahydrofuran, n-butyl acetate, isobutyl isobutyrate, glycol ethers such as 5 propylene glycol monomethyl ether and methyl cellosolve, alcohols such as ethanol and n-propanol and ketones such as methyl ethyl ketone. In general, the solvent system is evaporated from the coating composition once it is applied to an appro~",ate substrate. However, some insignifican~ amount of solvent may remain as residue. In addition, the monomer from the 10 photoadhering layer tends to diffuse into the color layer during overcoating process, so one way of providing the color layer with the monomer is not to include it in the coating solution of the color layer, but let it migrate there from the photoadhering layer during coating and drying process, or during l~min~tion of the layers. This process of monomer migration via diffusion is known to 15 those skilled in the art of creating multilayer im~ging systems. According tothe present invention, it is i."po,l~,l that the monomer be present in the colorlayer when the element is exposed to actinic radiation, regardless of the way itbecame the part of the color layer.
In the preferred embodiment, the photoadhering layer has a coating 20 weight between ap~ k;...~tely 2 and 20 g/m2. The most prert;"~d weight is from about 4 to 10 g/m2.
The photo~flh~rin~ layer cont~in~ a polymerizable monomer and may optionally contain such other desired components as uv absorbers, ~nti~t~tic compositions, optical brighteners, inert fillers, therm~l polymerizable inhibitors, 25 residual solvents, surf~ct~nts, ~ntih~l~tion agents, hydrogen atom donors, tackifiers, and plasticizers. Suitable photosensitive polymers nonexclusively include: a urethane adduct of polyvinyl butyral or other acetal resins Gont~ining hydroxy groups and isocyanatoethyl methacrylate, or reaction product of hydroxy-cont~inin~ acetal resins with methacrylic anhydride, acrylic 30 acid, acryloyl chloride, etc. Acrylic polymers cnnt~ining hydroxy groups can also be used as ~ubs~ es with all the above (meth)acrylic groups-containing WO 94/17451 21512 ~ 4 12 - PCTN594/00705 reagents, as can polyvinyl alcohols and their copolymers, phenolic resins, etc.
Other reactive groups on polymers which can be (meth)acrylated nonexclusively include: amino, carboxyl, epoxy, etc. The (meth)acrylated polyvinyl acetal polymers are preferred. The photoa&ering layer may optionally contain a uv absorber such as Uvinul D-50 available from GAF. It may also contain a plasticizer such as Resoflex R-296, available from Cambridge Industries. It may also contain ~nti~t~tic compounds, such as Gafac and Gafstat available from GAF.
The therrnoplastic adhesive layer should be coated directly on the photoadhering layer. The coating weight should be 2-20g/m2, more preferred 5-15 g/m2, most preferred 6-10 g/m2. The adhesive layer should be coated from a solvent which does not disturb the photoadhering layer undemeath.
Water is the prefelled solvent. Examples of thermoplastic resins coatable out of water nonexclusively include Carboset acrylic resins, polyvinyl acetate/crotonic acid copolymers, polyvinyl pyrrolidone/polyvinyl acetate copolymers, polyvinyl acetate emulsions, styrene/maleic anhydride copolymers, urethane polymers, etc.
The adhesive layer should be transferable to a receiver sheet in a temperature range of from about 50C to about 180C, preferably 60C to 120C, more preferably 60C to 100C when l~min~ted with heat and pressure.
The plasticizer may be present in an amount of up to about 10% by weight and the uv absorber up to about 10% by weight.
Receiver sheets may comprise virtually any material which can withstand the l~min~ting and dry development processes. White plastic sheets, such as adhesion plell~aled polyester Melinex 3020 film available from ICI, are useful for this purpose. Plastic coated paper sheets, such as polyethylene coated paper available from Schoeller, may also be used. Other bases may include wood, glass, metal, paper and the like.
In place of direct overcoafing one can assemble the hereinbefore described photosensitive element by hot-l~min~ting the layers to each other, as is well known in the art.
21~12~
WO g4117451 PCTIUS94/00705 T.~min~tion may be conducted by putting the a&esive layer in contactwith the receiver sheet and then introducing the materials into the nip of a pair of heated l~min?fin~ rollers under suitable pressure. Suitable l~min~ting temper~lu~es usually range from ap,uloxi"-ately 60C to 120C, preferably from 5 70C to 100C. The element is then exposed by means well known in the art.
Such exposure may be con~cte~ by exposure to actinic radiation from a light source through a co~lve~llional halftone negative color sep~lion under vacuum frame conditions. Mercury vapor discharge lamps are p~erelled over metal halide lamps. Other radiation sources, such as carbon arc, pulsed xenon, and 10 lase~s, may also be used. Light absorbing filters may be used to reduce light scalle""g in t}t~ ~terials.
After e~pQsure, a negative image is anchored via the photoa&ering layer and a&esive layer on the lect;ivel sheet by stripping the Ll~s~,arent cover sheet from the receiver sheet at room temperature with a steady, continuous 15 motion. The plere,led peel angle relative to the peel direction is greater than 90. The d~l~min~tion leaves the photoexposed areas of the color layer attached to the photoa&ering layer, which in its entirety is attached to the receiver sheet via the a&esive layer on the receiver sheet. The nonexposed areas of the color layer remain on the phenolic layer on the cover sheet which 20 has been peeled apart from the ,~c~i~/el sheet. Thus, a negative image remains on the receiver sheet.
In order to attain a multicolored image, another photosensitive element comprising, in order, a transparent cover sheet, crosslinked phenolic layer, a color layer, a photoa&ering layer and an a&esive layer is l~min~ted onto the 25 first image on the receiver sheet, exposed and the second color is dry developed by peeling apart the receiver sheet from the cover sheet of the additional photos~n~itive element. The second negative image remains with its photosensitive a&esive layer with the first image. A third and a fourth image may be added in a manner similar to that used to produce the second image. In 30 the usual case, four colored layers are employed to produce a full color WO 94117451 2 1 ~ 1 2 6 ll PCr/US94/00705 reproduction of a desired image. These four colors are cyan, magenta, yellow and black.
A matte finish of the final image may be obtained by embossing the shiny, top surface of the image with a matte material, such as Melinex 377 film 5 available from ICI. This is done by l~min~ting together the final image and matte m7~teri~1 and peeling the matte material away.
The final four color proof may be given a uniform, blanket exposure to photoharden the exposed, colored areas on the receiver base. A protective layer may also be l~min~ted on top of the last dry developed layer.
The following nonlimiting examples serve to illustrate the invention.
Example 1 Photoadherin~ Layer Solution To prepare the polymer with ethylenically unsalul~led groups useful in photoadhering layer, 50 g of Butvar 79 polyvinyl butyral resin from ~m~ntQ
c;Q~ g free hydroxyl groups (10.5-13%, tAI,-e;ssed as % polyvinyl alcohol) was placed in 200 g of n-buty~l acetate with stirring, at room temperature. To this solution, there were added 20 g of isocyanatoethyl methacrylate (Monomer, Polymer & Dajac Laboratories, Inc.), along with 0.05 g of dibulylliil dilaurea~eas catalyst. The nliAIule was left stirring ovemight, and after that time no isocyanate band was seen in the IR spectrum of the polymer. Thus, a polymer COI-l ~;lling methacrylate groups was created.
To 10 g of the above stock solution, there were added 0.38 g of Sartomer 399 Dipentae,ylh,ilol pentaacrylate (available from the Sartomer Co.), as monomer, and 0.1 g of 2-biphenyl-4,6-bis-trichloromethyl-s-triazine as initiator, completing the photoadhering layer formulation.
Phenolic Layer Solution 1. Methyl Ethyl Ketone (MEK) - 47 g 2. Dowanol PM - 47 g 3. Poly-p-hyd~oAy~lylene (6,200 MW, available from Hoechst Cel~n~se wo g41l74sl 2 1 ~ 1 2 6 ~ PCT/US94/00705 Corporation) - 3 g 4. Melamine-formaldehyde resin (Cymel 303, Cyanamid) - lg 5. p-Toluene sulfonic acid - 0.2 g This solution was coated on Melinex 505, 2 mil polyester available from ICI to 5 coating weight of .5 g/m2. The layer subsequently crosslinked upon drying in the oven at 110C for 2 minutes. Cro~clinking was verified by MEK rubs.
Color Layer Solution 1. Tetrahydrofuran - 21.7 g 2. Dowanol PM - 43.42 g 3. Diacetone alcohol - 16.18 g 4. Urethane adduct of 1 mole of trimethylhexamethylene diisocyanate with 2 moles of 2-hydroxyethyl-4,6-bis-acryloxyethyl isocyanurate (Aronix M-215, Mitsui) - 3.38 g 5. 2-biphenyl-4,6-bis-trichloromethyl-s-triazine - 0.84 g 6. Magenta Formvar Dispersion (19.8% solution) (The Dispersion consists, in percent by weight, of: 80.2% gamma-butyrolactone, 9.0 FORMVAR
12/85 polyvinyl formal resin ~available from ~on~nto Co.]) and 10.8%
Permanent C~rrnine FB) - 14.48 g 20 The color coat solution was coated on the crosslinked phenolic layer on the cover sheet and dried. The coating weight was 0.8 g/m2. The color coat was then overcoated with the above photoadhering layer solution with a Meyer rod #24 and dried. The coating weight was 6.8 g/m2.
The adhesive solution was Carboset XL-37 aqueous acrylic dispersion 25 (available from B.F. Goodrich). It was coated on the photoadhering layer with a Meyer rod #15 and dried. The coating weight was 6 g/m2.
The receiver base was Pres~m~teh Commercial Receiver Base, available from Hoechst Celanese Corporation.
The above-described photosensitive element was l~min~te(l to the above 30 receiver base using heat and p~ u,e. The thusly prepared composite was imagewise exposed to actinic radiation through the transparent cover sheet WO 94/17451 PCT/US94/0070~ --21512~ - 16-using a UGRA target for 15 seconds in a Berkey-Ascor exposure unit. Peeling away the cover sheet resulted in exposed areas of the color coat staying on the photoadhering layer, which in its entirety remained attached to the receiver sheet via the adhesive layer, while unexposed areas of the color coat were removed together with the cover sheet and the entire phenolic layer. The thusly obtained negative m~gent~ image anchored to the base via the adhesive showed dot reproduction of 3-97% at 150 lines/inch, and very low peel force.
Exposing the element for 30 and 45 seconds did not increase the peel force noticeably.
Col"~ ive Example 2 Example 1 was repeated, but the element did not contain the crosslinked phenolic layer. At 15 second exposure, the peel force of this element was comparable to that of the element of Example 1, but at 30 and 45 second exposure the peel force of the element of Example 2 increased sharply causing unwanted de-l~min~tion from the receiver sheet during peel development.
Example 3 Phenolic Layer Solution 1. Methyl Ethyl Ketone - 47 g 2. Dowanol PM - 47 g 3. Cresol/formaldehyde Novolak (S-Resin, available from Hoechst Celanese Corp.) - 3 g 4. Mel~mine/formaldehyde resin (Cymel 303, Cyanamid) - 1 g 5. p-Toluene sulfonic acid - 0.2 g The above solution was used in place of phenolic layer solution from Example 1, and the procedure was repeated. 20 second exposure and peel development afforded an image with 3-97% resolution at 150 lines/inch screen and low peel force, which did not increase appreciably with exposure.
21~1264 WO 94/17451 PCTnUS94/00705 Example 4 Phenolic Layer Solution 1. Methyl Ethyl Ketone - 47 g 2. Dowanol PM - 47 g 3. Poly-p-hyd.u"y~lyl~.le (20,000 MW, available from Hoechst Cel~nese Corp.) - 3g 4. Desmodur N-3300 (Polyisocyanate, Miles) - 1 g This solution wac used in place of the phenolic layer solution in Example 3.
Crosslinking was verified by MEK rubs of the phenolic layer after dlying, and 10 the coating procedures were repeated. After 20 second exposure and peel development the el~-Tne-nt showed 2-97% resolution and low peel force.
Comparative Example 5 This example illu~llales the necessity of crosclinking of the phenolic 15 layer prior to coating of sul?se~ t layers.
Phenolic Layer Solution 1. Methyl Ethyl Ketone - 47 g 2. Dowanol PM - 47 g 3. Poly-p-hyd,u~y:~lyltille (20,000 MW, available from Hoechst Cel~nese Corp.) - 3 g This solution was coated on 2 mil Melinex 505 polyester and dried. In the ~bsPnce of suitable crosclinker, the layer was easily ~tt~cl~ec~ by MEK.
Repeating the coating procedures of Example 1 on this sample, exposure for 45 25 seconds to light and peel development resulted in undesireably high peel forces.
Example 6 This example shows a pre~ alion of a four-color proof using the 30 present invention. The formulations for the color layers include the following ingredients in parts by weight.
WO 94/17451 ' ' ~ Pcr/uS94/00705 2 ~ 2 6 l~ . - 18 -Ingredient - Color Layer Cvan YellowMa~enta Black Tetrahyd,ufu,~, 200 200 200 200 4-hydroxy-4-methyl pentanone 150 150 150 150 1-methoxy-2-propanol 444 465 489 490 Formvar 12/85 resin 12 13 15 18 Sartomer 369 (Sartomer Co, Hydroxyethyl isocyanurate triacrylate monomer) 10 12 16 15 Hostaperm B2G 14 Permanent Yellow GR - 14 Permanent Red FBB - - 24 Printex 25 - - - 24 15 The pigments were dispersed in some of the Formvar 12/85 and solvents. The color solutions were coated on the cros~linked phenolic layer from Example 1 with a Meyer rod #12 and dried. The photoadhering solution from Example 1 was overcoated on each color layer with a Meyer rod #24, and dried, as was the Carboset XL-37 adhesive solution. The receiver base for the four-color 20 proof was Pres~m~tçh Commercial Receiver Base. The first photosensitive element, magenta, was l~min~ted to the receiver base by using heat and ple~,~,ule7 and imagewise exposed to actinic radiation through the transparent polyester cover sheet for 10 seconds. Upon peeling away the polyester cover sheet, the unexposed areas of the color layer were removed along with it, while 25 the exposed areas of the color layer remained anchored to the base via the photoadhering layer and the adhesive layer. Thus, a negative image was created on the receiver base, while a positive image was removed together with the transparent carrier sheet. The second photosensitive element, yellow, was in turn l~min~tecl to the previously created negative magenta image. Upon 30 imagewise exposure to actinic light via a target in registration with the previous image, and peeling away the polymer sheet, the yellow negative image was WO 94/17451 ~ 1 5 1 ~ ~ 4 PCT/US94/00705 created, attached to the previous image via the photosensitive adhesive.
Repeating the above procedure for the rem~ining two colors resulted in a high quality negative color proof.
S Conlpa~ e Example 7 This example describes the results when polymer other than one cont~inin~ phenolic groups is used in the crosslinked top layer.
Top Layer Solution 10 1. Methyl Ethyl Ketone - 47 g 2. Dowanol PM - 47 g 3. Carboset 526 (Acrylic Polymer, available from BF Goodrich) - 3 g 4. Cymel 303 - 1 g 5. p-Toluenesulfonic acid - 0.5 g 15 The top layer was coated on 2 mil Melinex 505 polyester and cros~linked during drying at 120C for 2 minutes The procedure from Example 1 was then followed. Exposures at 30 and 45 seconds resulted in high peel force and del~min~.on.
Example 8 This example illu~ tes the use of a methacrylated acrylic polymer in the photoa&ering layer.
15 grams of a copolymer of isobutyl meth~(rylate and hydroxyethyl methacrylate (75/25) were dissolved in 100 g of methyl ethyl ketone.
Methacrylic anhydride (4.5 g) was added, followed by 0.5 g of p-dimethylamino pyridine as catalyst. The mi~lu~e was refluxed for 6 hours, cooled, and the polymer was plt;ci~ ldd in water and dried. IR spectrum of the polymer showed the presence of unpolymerized methacrylate groups.
This polymer was used in place of the urethane adduct of Butvar B 79 and isocyanatoethyl methacrylate in Example 1. Following the procedure of WO 94/17451 2 1 ~ 1 2 ~ 4 PCr/US94/00705 ~
Example 1 resulted in image with resolution of 5-95% on 150 lines/inch screen.
Peel development of elements exposed longer did not reveal high peel forces.
Example 9 S This example illu~llates the ~ ion of the element of the present invention by l~min~tion rather than direct overcoating of all the layers.
The phenolic layer solution from Example 1 was coated on 2 mil Melinex 505 substrate and crosslinked. This was overcoated by the color layer solution from Example 1 and dried. On a separale sheet of polyester, 3 mil Melinex 516 available from ICI, was coated photoadhering layer solution from Example 1 and dried. This was overcoated with the adhesive layer solution from Example 1 dried.
The element on Melinex 516 was then l~min~ted to a receiver sheet identical to that used in Example 1 and the Melinex 516 polyester sheet was peeled off. This created an element, con~i~ting of, from top to bottom:
photoadhering layer, adhesive layer, and receiver sheet. To this element, there was l~min~tefl color layer in contact with the photoadhering layer, the element on Melinex 505. The newly created multilayer element was exposed to actinic radiation analogously to Example 1 and peel-developed. An image with resolution of 3-97% was created, and longer exposures did not increase the peel forces.
Example 10 This example illu~llates incorporating a monomer in the color layer by controlled diffusion of the monomer from the photoadhering layer.
Color Layer Solution:
1. Tetrahy.lrorul~l - 21.7 g 2. Dowanol PM - 43.42 g 3. Diacetone alcohol - 16.18 g 4. Magenta Formvar Dispersion (19.8% solution) (The Dispersion consists, in percent by weight, of: 80.2% garnma-butyrolactone, 9.0 FORMVAR
12/85 resin and 10.8% Permanent Carmine FB) - 14.48 g 5. Irgacure 369 (2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one initiator, Ciba-Geigy) - 0.5 g This color solution was coated on the crosslinked phenolic layer from Exarnple 1 with Meyer rod #10 and dried. Since it does not contain a monomer, it is not expected to be photopolymerizable. A controlled experiment was performed, in which the above element was imagewise irradiated for 10 minutes with actinic light, and thelearler rubbed with a pad soaked in ethyl acetate. The color coating readily dissolved, indicating that no photopolymerization took place, asexpected.
Photoadherin~ Layer Solution 1. Stock Solution from Example 1 - 10 g 2. Sartomer 399 monomer - 0.38 g 3. Irgacure 369 Photoinitiator - 0.01 g This solution was overcoated on above-described color element with a Meyer rod #24 and dried to give the photoadhering layer. This layer was then peeled off the color layer and discarded. Now the color layer was imagewise exposed to actinic light for 10 minutes and rubbed with a pad soaked in ethyl acetate.
The exposed areas of the color layer were insoluble due to photopolymerization, while the unexposed areas dissolved as before. IR
showed the presence of acrylic monomer in these areas. This monomer 2~ diffused into the color layer from the photoadhering layer.
Another element was prepared as described above. The photoadhering layer was not peeled off, but overcoated with an adhesive layer, as described inExample 1. T.~nnination to receiver sheet, imagewise exposure and peel development of the element gave an image with 3-97% resolution.
Diffusion of liquid monomers between layers in multilayer elements is known in the art. Thus, in order to provide the color layer with a monomer, WO 94117451 Pcrtuss4/00705 21 ~1 2 6 ll - 22 -one can either include the monomer in the color solution in the first place, or not include it, but let it diffuse from the photoadhering layer, or both include it, and let the additional monomer diffuse from the photoadhering layer into the color layer. The final element, thus, comprises at least one monomer in both 5 color and photoadhering layers
Claims (18)
1. A photosensitive element which comprises, in order from top to bottom (i) a strippable, transparent cover sheet;
(ii) a crosslinked layer, which comprises a polymer having phenolic groups;
(iii) a color layer, which comprises an organic binder, a polymerizable monomer, a colorant, and optionally, a photoinitiator, wherein the binder is present in sufficient amount to bind the color layer components into a uniform film, wherein the optional photoinitiator, when present, is present in sufficient amount to initiate polymerization of the polymerizable monomer, wherein the polymerizable monomer is present in sufficient amount to provide image differentiation when the element is imagewise exposed to actinic radiation and wherein the colorant is present in an amount sufficient to uniformly color the color layer;
(iv) a photoadhering layer, which comprises a photosensitive polymer having ethylenically unsaturated, photocrosslinkable groups and a molecular weight greater than 3,000, a polymerizable monomer having at least one ethylenically unsaturated group, and an optional photoinitiator, wherein the optional photoinitiator, when present, is present in sufficient amount to initiate polymerization of the polymerizable monomer and the crosslinking of the photosensitive polymer and wherein at least one of either the color layer or the photoadhering layer contains a photoinitiator;
(v) a thermoplastic adhesive layer;
(vii) a receiver sheet
(ii) a crosslinked layer, which comprises a polymer having phenolic groups;
(iii) a color layer, which comprises an organic binder, a polymerizable monomer, a colorant, and optionally, a photoinitiator, wherein the binder is present in sufficient amount to bind the color layer components into a uniform film, wherein the optional photoinitiator, when present, is present in sufficient amount to initiate polymerization of the polymerizable monomer, wherein the polymerizable monomer is present in sufficient amount to provide image differentiation when the element is imagewise exposed to actinic radiation and wherein the colorant is present in an amount sufficient to uniformly color the color layer;
(iv) a photoadhering layer, which comprises a photosensitive polymer having ethylenically unsaturated, photocrosslinkable groups and a molecular weight greater than 3,000, a polymerizable monomer having at least one ethylenically unsaturated group, and an optional photoinitiator, wherein the optional photoinitiator, when present, is present in sufficient amount to initiate polymerization of the polymerizable monomer and the crosslinking of the photosensitive polymer and wherein at least one of either the color layer or the photoadhering layer contains a photoinitiator;
(v) a thermoplastic adhesive layer;
(vii) a receiver sheet
2. The element of claim 1 wherein both the color layer and the photoadhering layer contain a photoinitiator.
3. The element of claim 2, wherein the ethylenically unsaturated polymerizable monomer is delivered to the color layer by interlayer diffusion during assembly of the photosensitive element.
4. The element of claim 3 wherein the polymerizable monomer in steps A (iii) and A
(iv) comprises one or more monomers selected from the group consisting of triethylene glycol dimethacrylate, tripropylene glycol diacrylate, tetraethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol dimethacrylate, pentaerythritol tetraacrylate, di-pentaerythritol pentaacrylate, trimethylol propane triacrylate, trimethylol propane trimethyacrylate, pentaerythritol triacrylate, bisphenol A ethoxylate dimethacrylate, trimethylolpropane ethoxylate triacrylate, trimethylopropane propoxylate triacrylate, diacrylate bisphenol A
diepoxide dimethacrylate and bisphenol A diepoxide diacrylate.
(iv) comprises one or more monomers selected from the group consisting of triethylene glycol dimethacrylate, tripropylene glycol diacrylate, tetraethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol dimethacrylate, pentaerythritol tetraacrylate, di-pentaerythritol pentaacrylate, trimethylol propane triacrylate, trimethylol propane trimethyacrylate, pentaerythritol triacrylate, bisphenol A ethoxylate dimethacrylate, trimethylolpropane ethoxylate triacrylate, trimethylopropane propoxylate triacrylate, diacrylate bisphenol A
diepoxide dimethacrylate and bisphenol A diepoxide diacrylate.
5. The photosensitive element of claim 1 wherein the photoinitiator comprises one or more photoinitiators selected from the group consisting of 2,3-di(4-methoxyphenyl)quinoxaline, 9-phenylacridine, 2-biphenyl-4,6-bis-trichloromethyl-5-triazine, bis(2,4,5-triphenyl)imidazole, bis-trichloromethyl-s-triazine, acetophenones, thioxanthones, and their derivatives.
6. The element of claim 1 wherein the color layer comprises one or more organic binder selected from the group consisting of styrene/maleic anhydride copolymers and their half esters; acrylic polymers and copolymers; polyamides; polyvinyl pyrrolidones;
cellulosic resins; phenolic resins; polyvinyl acetals, polyvinyl acetates and their copolymers.
cellulosic resins; phenolic resins; polyvinyl acetals, polyvinyl acetates and their copolymers.
7. The element of claim 1 wherein the polymerizable monomer is present int he color layer in an amount ranging from about 5% to about 50% by weight of the color layer.
8. The element of claim 2 wherein the photoinitiator is present in the photoadhering layer in an amount ranging from about 5% to about 20% by weight ofthe photoadhering layer.
9. The element of claim 1 wherein the binder is present in the color layer in anamount ranging from about 20% to about 80% by weight of the color layer.
10. The element of claim 1 wherein the receiver sheet comprises polyethylene terephthalate.
11. The element of claim 1 wherein the cover sheet comprises polyethylene terephthalate.
12. The element of claim 1 wherein the color layer further comprises one or moreingredients selected from the group consisting of plasticizers, tackifiers, stabilizers, antistatic compositions, uv absorbers, spectral sensitizers, optical brighteners, inert fillers, exposure indicators, polymerization inhibitors, surfactants, hydrogen atom donors, antihalation agents, and photoactivators.
13. The element of claim 1 wherein the coating weight of the photoadhering layerranges from about 2 to 20 g/m2.
14. The element of claim 1 wherein the photoadhering layer further comprises oneor more ingredients selected from the group consisting of plasticizers, tackifiers, stabilizers, antistatic compositions, uv absorbers, spectral sensitizers, optical brighteners, inert fillers, exposure indicators, polymerization inhibitors, surfactants, hydrogen atom donors, antihalation agents, and photoactivators.
15. The element of claim 1 wherein the the receiver sheet comprises paper, coated paper, or polymeric film.
16. A method for producing a negative image which comprises:
A) providing the photosensitive element of claim 1;
(B) imagewise exposing the color layer and the photoadhering layer to actinic radiation through the transparent cover and crosslinked phenolic layer;
(C) peeling apart the receiver sheet and the transparent cover sheet, leaving exposed areas of the color layer attached to the receiver sheet via the photoadhering layer and adhesive layer and unexposed areas being removed with the cover sheet and the crosslinked phenolic layer, thereby forming a colored negative image on the receiver sheet; and (D) optionally repeating steps A) through D) at least once wherein another photosensitive element having at least one different colorant, is transferred via its photoadhering and adhesive layers to the negative image previously produced on the receiver sheet.
A) providing the photosensitive element of claim 1;
(B) imagewise exposing the color layer and the photoadhering layer to actinic radiation through the transparent cover and crosslinked phenolic layer;
(C) peeling apart the receiver sheet and the transparent cover sheet, leaving exposed areas of the color layer attached to the receiver sheet via the photoadhering layer and adhesive layer and unexposed areas being removed with the cover sheet and the crosslinked phenolic layer, thereby forming a colored negative image on the receiver sheet; and (D) optionally repeating steps A) through D) at least once wherein another photosensitive element having at least one different colorant, is transferred via its photoadhering and adhesive layers to the negative image previously produced on the receiver sheet.
17. The method of claim 16, further comprising producing the elements of claims 2-15.
18. The method of claim 16 wherein each lamination is conducted at a temperatureof from about 60°C to about 120°C.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/006,879 US5300399A (en) | 1993-01-21 | 1993-01-21 | Negative working, peel developable, single sheet color proofing system having a crosslinked layer containing a polymer with phenolic moieties |
| US08/006,879 | 1993-01-21 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2151264A1 true CA2151264A1 (en) | 1994-08-04 |
Family
ID=21723070
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002151264A Abandoned CA2151264A1 (en) | 1993-01-21 | 1994-01-19 | Negative working, peel developable, single sheet color proofing system having a crosslined layer containing a polymer with phenolic moieties |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US5300399A (en) |
| EP (1) | EP0680625B1 (en) |
| JP (1) | JPH08507157A (en) |
| CA (1) | CA2151264A1 (en) |
| DE (1) | DE69417399T2 (en) |
| DK (1) | DK0680625T3 (en) |
| WO (1) | WO1994017451A1 (en) |
Families Citing this family (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5545506A (en) * | 1992-01-28 | 1996-08-13 | Hoechst Celanese Corporation | Method of producing an image using a negative working, peel developable, single sheet color proofing system |
| DE4204949A1 (en) * | 1992-02-19 | 1993-09-09 | Hoechst Ag | METHOD FOR PRODUCING A MULTICOLORED IMAGE AND LIGHT-SENSITIVE MATERIAL FOR CARRYING OUT THIS PROCESS |
| US6010824A (en) * | 1992-11-10 | 2000-01-04 | Tokyo Ohka Kogyo Co., Ltd. | Photosensitive resin composition containing a triazine compound and a pre-sensitized plate using the same, and photosensitive resin composition containing acridine and triazine compounds and a color filter and a pre-sensitized plate using the same |
| DE4311949A1 (en) * | 1993-04-10 | 1994-10-13 | Hoechst Ag | Photopolymerizable material and process for producing a colored image |
| US5436112A (en) * | 1994-04-01 | 1995-07-25 | Hoechst Celanese Corporation | Method for producing a negative image with color proofing element containing a urethane monomer |
| US5660968A (en) * | 1995-05-05 | 1997-08-26 | Bayer Corporation | Negative working, peel developeable, single sheet color proofing system with improved background color |
| US5707781A (en) * | 1995-05-05 | 1998-01-13 | Bayer Corporation | Photopolymerizable compositions having acyl or diacyl phosphine oxide and a fluorescent optical brightner |
| US5686221A (en) * | 1995-12-27 | 1997-11-11 | Bayer Corporation | Negative working peel apart color proofing process |
| US5856064A (en) * | 1996-09-10 | 1999-01-05 | Minnesota Mining And Manufacturing Company | Dry peel-apart imaging or proofing system |
| US6013409A (en) * | 1996-09-10 | 2000-01-11 | 3M Innovative Properties Company | Dry peel-apart imaging process |
| US5738970A (en) * | 1997-03-24 | 1998-04-14 | Bayer Corporation | Negative working, peel developable, single sheet color proofing system with polyvinyl acetal photoadhering layer |
| JPH11109621A (en) * | 1997-07-08 | 1999-04-23 | Agfa Gevaert Nv | Developing material for manufacturing negative color proof, method therefor and method for manufacturing both of positive and negative color proofs on one image receiving material |
| BR9805051A (en) * | 1997-12-05 | 1999-12-07 | Bayer Ag | Positive work detachable-revealable color proof system. |
| US5928834A (en) * | 1998-03-19 | 1999-07-27 | Agfa Corporation | Spot gloss film for color images |
| US6143461A (en) * | 1999-09-15 | 2000-11-07 | Agfa Corporation | Process for obtaining a color image with improved resolution |
| US6409017B1 (en) | 2000-06-30 | 2002-06-25 | Corning Incorporated | Use of inhibitor in optical fiber reel covers |
| US6602601B2 (en) | 2000-12-22 | 2003-08-05 | Corning Incorporated | Optical fiber coating compositions |
| JP4401262B2 (en) * | 2004-02-02 | 2010-01-20 | 富士フイルム株式会社 | Planographic printing plate precursor |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6032173B2 (en) * | 1974-12-28 | 1985-07-26 | 富士写真フイルム株式会社 | Image forming method |
| US4260673A (en) * | 1979-09-05 | 1981-04-07 | Minnesota Mining And Manufacturing Company | Single sheet color proofing system |
| US4489154A (en) * | 1983-12-22 | 1984-12-18 | E. I. Du Pont De Nemours And Company | Process for preparing a surprint proof |
| JPH0719051B2 (en) * | 1985-02-15 | 1995-03-06 | 富士写真フイルム株式会社 | Photosensitive transfer sheet |
| JPH0719052B2 (en) * | 1985-02-19 | 1995-03-06 | 富士写真フイルム株式会社 | Image forming method |
| US5183723A (en) * | 1988-10-21 | 1993-02-02 | Hoechst Celanese Corporation | Colored image on a degradable sheet material and method of formation |
| EP0413863A1 (en) * | 1989-08-24 | 1991-02-27 | Toyo Ink Manufacturing Co., Ltd. | Image-forming process and image-forming material |
| US4963462A (en) * | 1990-01-08 | 1990-10-16 | Hoechst Celanese Corporation | Positive working, peel developable, color proofing system having two photosensitive layers |
| CA2037804A1 (en) * | 1990-03-13 | 1991-09-14 | Richard P. Pankratz | Polyolefin backside coating for photosensitive reproduction element |
| US5545506A (en) * | 1992-01-28 | 1996-08-13 | Hoechst Celanese Corporation | Method of producing an image using a negative working, peel developable, single sheet color proofing system |
-
1993
- 1993-01-21 US US08/006,879 patent/US5300399A/en not_active Expired - Fee Related
-
1994
- 1994-01-19 EP EP94907847A patent/EP0680625B1/en not_active Expired - Lifetime
- 1994-01-19 DK DK94907847T patent/DK0680625T3/en active
- 1994-01-19 WO PCT/US1994/000705 patent/WO1994017451A1/en active IP Right Grant
- 1994-01-19 CA CA002151264A patent/CA2151264A1/en not_active Abandoned
- 1994-01-19 JP JP6517174A patent/JPH08507157A/en active Pending
- 1994-01-19 DE DE69417399T patent/DE69417399T2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| EP0680625B1 (en) | 1999-03-24 |
| JPH08507157A (en) | 1996-07-30 |
| DK0680625T3 (en) | 1999-10-11 |
| DE69417399T2 (en) | 1999-08-26 |
| DE69417399D1 (en) | 1999-04-29 |
| EP0680625A1 (en) | 1995-11-08 |
| US5300399A (en) | 1994-04-05 |
| WO1994017451A1 (en) | 1994-08-04 |
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