CA2252613A1 - Glittering cube-corner article - Google Patents

Abstract

A glittering non-reflective sheeting (60) includes an array of cube-corner elements (30) that are arranged in the array such that the sheeting glitters when light is incident thereon. The glitter is in the form of many discrete points of light (68) that tend to blink off and on. The array may be configured such that a dihedral angle .alpha. varies between adjacent cube faces (31) of adjacent cube-corner elements (30) in each groove in one of the groove sets (45, 46, or 47) and such that the base planes (36) are not parallel to each other when the sheeting (60) is laid flat. Preferably, the dihedral angle .alpha. between faces (31) of adjacent cube-corner elements (30) varies in essentially all of the grooves such that the cube-corner elements are randomly tilted throughout the array. The glitter can make the sheeting very useful for aesthetic or decorative applications.

Description

GLIT~ERING CUBE_CORNER ART~CLE

This invention pe,la;ns to a cube-comer article that glitters when exposed to light.
Glittering articles have been produced for many years. The articles often are used for dccGlali~re ~l",Gses. Cllstomarily, glitter has been producedby h~co,l,o.~ling or s~ eJ.di~g metallic particles into a substrate. Flakes of finely divided metallic pa.licles such as copper, silver, ~ or the like have been inco,},olaled into polymeric s~lbsl~ales as documented by US.
Patents S,470,058, 5,362,374, 5,202,180, 3,988,494, 3,987,229, and 3,010,845. Finely divided metal flakes have also been placed in a coating substrate -- see U.S. Patents S,276,075, 3,988,494, 3,697,070, and 3,692,731.
In another approach, U.K. Patent No. 1,516,686 discloses a glittering product that is produced from non-met~ eed and non-reflective substrate on which a metallic, reflecting fflm is hot pressed, cirnl~t~neously forming an h,lpression or copy from a printing block. The copy is engraved with adjacent zones formed by nclwolks with varying orientation and which are too fine to be seen by the naked eye, the result being the fo,l~laliol~ of glittering zones created by the valley and peaks of the n~,lw~rks. The glittering zones (i.e., iridescence) are produced on a non-met~llieed and non-reflective substrate.
Cube-comer articles have been used in the r~trorenective field for many years. See, for eY~mple, U.S. Patents 5,138,488, 4,775,219, 4,588,258, 4,066,331, 3,923,378, 3,684,348, 3,541,606, and Re 29, 396. The articles are capable of le~u~lung ;,ubst~nlial ~ r.lil;es of incident light back towards the light source, and ll.erefole have becon,c commonly used on road signs, barricades, and safety vests.
FIGs. 1 and 2 illustrate an ~"~a~"ple of a cube-corner rel,oreflective sheefing, noted generally by numeral 10. The array of cube-corner elements 12 project from a first or rear side of a body portion 14 that incllldes a body layer ~ 30 18 (also rt;~ ,d to in the art as an overlay) and may also include a land layer 16. Light enters the cube-corner .e~eeting 10 through the front surface 21; it then passes through the body portion 14 and strikes the planar faces 22 of the cube-corner cl--..c .1~12 to return in the direction from which it came as shownby arrow 23.
FIG. 2 shows the back side ofthe cube-corner clc --f .~c 12, where each 5 cube-corner element 12 is in the shape of a trihedral prism that has three exposed p}anar faces 22. The cube-corner ~lc~ 12 in known arrays are typically defined by three sets of parallel v-shaped grooves 25, 26, and 27.
~djacent planar faces 22 on adjacent cube-corner c~ nls 12 in each groove form an external dihedral angle (a dihedral angle is the angle forrned by two 10 inte. ~e-;lh~g planes). This external dihedral angle is consku~l along each groove in the array. This has been the case for a variety of previously produced cube-corner arrays.
Althoueh cube-comer shçetin_ is known to provide very effective relro,t;nectivity, the ~h~oeti~ that have been herelofole developed are not 15 known for displaying a glittering apped. ance~
The present invention provides a new and very dirrere,.l approach to providing a glittering article. Rather than use met~llic particles or flakes, as has been done in the prior art, the present invention produces glitter from a cube-corner .~l~e,,~ p that has a new arra~ment of cube-corner elements. In brief, 20 the invention is a glittering non-rell~r~llective ~heeting that in~ des an array of cube-corner el~."e~,t..; that are a-l~ged such that the sheeting glitters when light is inrident thereon.
The terms "glitter", "glitters", or "glittering" are used herein to mean a ~--ltir!icity of discreet regions of light that appear as distinct points of light, each of which may be noticed by the lm~ided eye of an oldina-y observer when light is incident on the sheeting, but which points of light disappear or becomeunnoticeable to the eye of the same observer when either the angle of the incid.ont light source to the shçetine the angle of observation, the shç~lh~e's orientation, or a cGrllbh-alion thereof are ch~nged The glitter enh~ncçs the sl.Ç~ti~e~s conspicuity, and may filrnish the sheetin_ with an ncsthetiC appeal and may also be useful for producing graphic W O 97/41462 PCTrUS96/13146 images such as product id~ e~ ~. The glittering che.,~ p. may also be useful as a decorative material and for providing decorative feat~les to other articles.
These advantages and others are more fully described below in the det~iled descliy~ion ofthe invention.
FIG. 1 is a sectionsl view of a prior art cube-corner sl-e~ g 10.
FIG. 2 is a bottom view of the prior art ~eLlulenective cheeting 10 illustrated in FIG. l.
FIG. 3 is an isometric view of a cube-corner e4~..cnl 30 that may be used in a glille~;nB sh~e~ g ofthe invention.
FIG. 4 is a bottom view of a glittering sheetine 60 in accordance with the present invention.
FIG. 5 is a sectio~' view of a glittering sheetin 60 taken along lines 5-5 of FIG. 4.
FIG. 6 is a bottom view of a glittering sheeting 60, illustrating apex and groove intersection heights from a ~ererence plane.
FIG. 7 is a sectional view of a glill~, hlg sheeting 60 taken along lines 7-7 of FIG. 5.
FIG. 8 is a s~h~mstic view of how a glille,i,.g ;~hee~ g can be made by exposing a sh~eting 10 to heat and pressure in a l~rnin~ting appalal~ls 71.
FIG. 9 is a schem~tic view of an alternative method of exposing a .che~ine 10 to heat and pressure to produce a glittering ~hPeting 60.
FIG. 10 is a top view of a mold 79 that may be used to produce a glittering sheeti~
FIG. 11 is a sl-h~ ;c view of a second technique for making a glittering Cl~e~ g 60 by casting the -hr~ g from a mold 79.
FIG. 12 is a front view of an imaged ~heeting lOl that has glittering and non-g1ittering regions 102 and 103, respectively.
FIG. 13a is a side view of an insert 104a that may be used to produce an image in a ~lilLe.ing ~heeting of the present invention.
FIG. 13b is a side view of an insert 104b that may be used to produce a glittering ~l-e~ g of the present invention.

W O 97/41462 PCT~US96/13146 DFTA~r.Fn DESC~PTIO~ OFPREFERRED EA~BOD~TS
In the practice of the present invention, a new ~he. ~ p is provided that can glitter when exposed to light. The cheeting may display at least about 10, and preferably at least about 50, points of light per square c~ntimeter (cm2) 5 when the sheeting is viewed under direct sunlight from the back side of the array of cube-corner ~ nl s Typically there are less than about 250 points of light per cm2 when viewed under direct sllnlight Thus, a cheeting that ocG~ es slightly more than a few square c~ te-~ in area can produce hundreds, or to borrow a phrase from a former United States ~esident, "a 10 thousand points of light", to enh~nce ~o~ pl~-ity and nes~hetic appeal of the ~e~
The gliue,i,.g effect is achieved by ol;e.lflng cube-corner elemente in a new geomel,;c arran&~ ~F -t In a prere.lcd embodiment of this new geoll.~l-ic p,~..n~l~l, at least one set of parallel grooves in an array of cube-corner 15 elemPnts has faces of a~ cçnt cube-corner elPments arranged such that the extemal dihedral angle formed between the faces varies along at least one groove in the set.
In another p,e~.led embodiment, the external dihedral angle belween faces of ~ Ijac~nt cube-corner e4~ varies in all grooves to such an extent 20 that the cubes are randomly tilted across the array. What is meant by "randomly tilted" is that the cubes in the sheetin~ are tilted in a nomepealitlgpattern relative to a reference plane that can be the front surface of the glittering eheetin~ when laid flat. A cube is considered "tilted" when its optical axis is not perpen~lic~lqr to the r~re,~nce plane. The "optical axis" is 25 customarily understood as being the internal line that extends from the cube apex and forms equal angles with each cube edge that extends from the apex.
In other words, the optical axis is the line defined by the intersection of three planes that each bisect one of the three internal dihedral angles formed by the cube-corner clc.,.~n~'~ three planar faces. All previously known cube-corner 30 ~heeting~ have had the cube-corner P~ ~langed in a predetermined l~,peali..g pattern throughout the array. If a known cube-corner eheetir~ is W O 97/41462 pcTnus96ll3l46 tho~ of as an army that ~-~ches in cadence in strict formation, a randomly-oriented sheeting would be a drunken army where each cube-corner clc.n~l ~-ese~led individual soldiers that staggered and bumped into one another'as they mdr~,hed.
FIG. 3 illustrates a cube-corner Plem~nt 30 that is useful in glittering she~ g~c ofthe invention (60, FIG. 4) as well as in ~ ol~llective ch~e~ings of the prior art (10, FIG. 1). As shown, a cube-corner elc ~cnl 30 is a body that has three mutually perpen~lic~l?r faces 31a, 31b, and 31c that meet at the cube's apex 34. The cube's base edges 35 are generally linear and generally lie 10 in a single plane that defines the base plane 36 of the e~lc." n 30. Cube-corner el~-n~ 30 also has a central axis 37, which is the tri-sector of the internal angles defined by lateral faces 31a, 31b, and 31c. The optical axis may be disposed perpen-lic~ r to the base plane 36, or it may be canted as described inU.S. Patent No. 4,588,258 to Hoopman and U.S. Patent No. 5,138,488 to .~7c7ech In addition to defini~ a single cube-corner by a three-sided pyramid having a tri~n~llAr base plane such as di~c1osed in the Hoopman patent, the cube-corner elçrn~nts may be defined by a re~ r base, two rect~ne~ r sides, and two triAn~lDr sides such that each structure has two cube-corners each such as disclosed in U.S. Patent No. 4,938,563 to Nelson et al., or may be of e sse-.l ;Ally any other cube-corner shape.
FIG. 4 shows the structured surface or bacL~i~e of a cube-corner eeting 60, which inrl~ldes a unitary or single layered array of cube-corner ~le-~ 30, like those depicted in FIG. 3. Each cube-corner element 30 meets, but is not necess-.;ly col-n~ed to, an ad~ent cube-corner element at a base edge 35. The array inrludes three sets of generally parallel grooves 45, 46, and 47. The externsl dihedral angles (a, FIG. 5) bet~.cen faces 31 of ndj~ent cube-corner P~ enls 30 vary along the grooves 4~47 in the array.
The cube-corner el~ nl e in the array sre randomly tilted, and because of this, the apex 34 of one cube, such as cube 30a may be relatively close to another apex such as cube 30b, but cube 30b's apex may then be farther away from another ~ ent apex such as the apex of cube 30c.
s , ~ .. , .. ~

W O 97/41462 PCTrUS96/13146 FIG. 5 also illustrates the position of one cube apex relative to another and additionally shows how the cube's base edges 35 do not lie in the same common plane. The base edge 35 of one cube may be disposed closer to or farther away from the front surface 51 of glittering sl-eel;-lp 60 than the base5 edges of other ~d,~-nt cube-corner f~ s And in a single cube, points on one of its base edges 35 may be located closer to or farther away from front surface 51 than points on another base edge 35 in the same cube. Base edges 35 define the lowest point of grooves 45-47 -- and because edges 35 do not all lie in the same plane, the grooves have a varying pitch along their length. If the 10 cube-corner cheeting possesses a land layer 56, it too is also not ~".iro.,l.ly spaced from the front surface 51. When the cube-corner clel,.enl~ are tilted, the base planes 36 (FIG. 3) of each cube-corner elF.~ nl are not parallel, and they do not reside in the same plane. Many of the base planes also do noe reside in the same plane as the front surface 51 -- that is, the base planes are15 not parallel to the ~l~eeth~g~s front surface 51 when the eheeting is laid flat on a surface.
Cube-corner elempnt ~,eet;i-gs have been produced where some of the elemçnt's base planes do not reside parallel to the sh~ g's front surface when the .cheel;.,g is laid flat. Such sheeting.e, however, are rellorenective and 20 therefore have had the array of cube-corner Plçmente disturbed or rearranged in certain areas by sealing a film to the ba~Q;de of the array (such as ~ clle~ed below with ~e~e-ence to FIGs. 8 and 9) or by crealing bubbles (~J.S. Patent 5,485,311 to McAllister). The seal line and the bubbles upset the sheeth~g~s front surface and the orientation of the cube-corner ele.--~ in the array. For p~llJOSes of this invention, Ihel~rore, a eheeting is not considered to be "laidflat" in those areas where the sl~e~t;-~, is dislu,l,ed by seal lines (item 64 FIGS.
8 and 9) or bubbles (24 of the '311 patent). The base planes 36 (FIG. 3) in Rhf~.eting.s of the invention may be offset at angles of zero to 90 degrees fromthe refelencc plane or front surface when the cl,ec~ g is laid flat. The base 30 planes that are tilted relative to the front surface of the .~h~e~ g when laid flat typically form an angle of about 1 to 10 degrees from the front surface.

.... .

W O 97/41462 PCTrUS96/13146 FIG. 5 also shows the extemal dihedral angle, a, that defines the angle bct~c~,n faces 31 (FIG. 4) of a~ e!lt cube-comer ~l&.n~ ts 30. Angle a may vary along some or all grooves in a single generally parallel groove set, it mayvary along some or all grooves in t-wo generally parallel groove sets, or it may5 vary along some or all grooves in all three generally parallel groove sets in the array. In an array of randomly tilted cube-corner ~ ..f ~ , angle a varies randomly ~ ~~ cent faces of adjacent cube-comer rl.~",~ $ throughout essentially the whole array that is in~entled to glitter. Angle a may vary from zero degrees to 180 degrees, but on average ranges from about 35 to 115 10 degrees for dihedral angles b~ .,e.~ faces of ~ cent cubes.
FIG. 6 illustrates some typical di~tPnces of apexes 34 and groove intersections from the .~heeti~'s front surface 51 (FIG. 5). The cube-comer e".~"l in the upper left hand comer of the array has an apex that is spaced 350 t o...~,lers from the front surface 51. The fourth cube over from the upper left-hand comer, however, has an apex height of 335 micrometers.
There is thus a dil~re.lce in apex height of 15 micrometers bt;tw~en cubes that are fairly close to one another. The cube-comer ele."ents typically have an average height of about 10 to 500 mic.om.,te.~, more typically of about 20 to 200 miclo".~,le.~. For cube-comer el~.-)c.~ls that are about 20 to 200 ll,icro~ s high, the variation in height b~ween adjar~nt apexes typically is about 0 to 60 mic-~ er~ and typically is about 1 to 40 micrometers on average, more typically 2 to 25 micrometers on average, but preferably does not exceed more than 50 micro~eLe~ on average. The variation in height b~t~,ell n~;~c~nt groove inle.~c.,lions for such cubes typically is about 0 to 100 mic,ol~le.~ and typically is about 3 to 50 ~,L.c,omele,~ on average, but preferably does not exceed more than 60 micrometers on average.
The body }ayer 58 (FIG. 5) in body portion 54 (FIG. 5) typically has an average thickness of applo~ ely 20 to 1200 micrometers but could be csse~ ly any tkic~ .~ecs. The optional land layer 56 (FIG. 5) pre~l ~bly is kept- 30 to a minimal thickness of 0 to less than about 100 mic,or.,~tt;,~.

In the cube-corner o~ array shown in FIGs. 4-6, the groove sets 45, 46, and 47 are illustrated as being parallel. It is within the scope of thisinvention, however, for grooves of the same set to be other than parallel.
Some grooves may be parallel and others may not. Some grooves may run 5 parallel to ~dj~~~nt grooYcs of the same groove set in some regions of the cho~ e but may also cross paths or overlap those same grooves. In such qnccs, the cube-corner c~ ls may pile up on each other. As long as there are two or more grooves that extend in the same general d;l~cLioll roughly parallel to each other, those grooves are viewed as being "generally 10 parallel" regardless of WLflhf~ the grooves at some other point cross paths, overlap, converge, or diverge.
~ lth~lgh ~he~ ,gs of the invention Col~ iSe, an array of cube-corner C4 --~f ~~1~ that normally would allow the cheetin to r~l- ort;nect light in~i~P~nt on front surfaces 51, ~ ,.ing sl.eet;~s of the invention are rendered 15 nonret~ t;nective by making the body portion S4 or cube-corner el~PmPntc opaque, for example, by using fillers, opaque pi~nentQ~ flakes, or other particulate additives, or by preventing light from passing through the front surface 51 of cheeting 61 by placing an opaque coating or film (not shown) on the shee~ ,'s front surface 51 or by placing the Q~hPeting face down on an 20 opaque surface. Gliut~ g cheetingc are also rendered non-lelro,~Ilective by coating or applying materials to the bacl~Q;des of the cube-corner Pk ..f-~lS
~ltçrnqtively~ the glille-ing cl~e~ of the invention may be rendered non-rel.olenective by altering the exposed cube-corner faces such as by etching or by altering the internal cube-corner geon~ -y. Glittering ~he~ gc of the 25 invention may also be used with the front surface typically mollnted to or juAlaposed against another substrate such that the back side of the array of cube-corner ele nf .~t~ is exposed to light. Light incidPnt on the bael~citle of the array of cube-corner clo-~ c is reflected toward a viewer in a nonuniform pattern such that .I~nIeJ~US points of light become visible to the viewer as 30 glitter.

W O 97/41462 PCT~US96/13146 FIG 7 shows cube-comer ete~ te.~e~,~ed by a plane that is parallel to the glittering cheeting's front surface 51 (FIG 5) As illustrated, the plane intersects the cube-comer ele ..~ .Is to produce triangles 62 of uli~rer~
cross-sectio~ areas Some cubes may be tilted to such an extent that the 5 int~.~ccling plane only passes through a tip of the cube, resl.ltin~ in a small tri~n~ r cross-section -- whereas, a cube that stands upright may be intersected such that the triangle rçsulting from the cross-section is relatively large Thus, even though the cube-corner el~ ..Pn~ in the array may be of similar size, they can produce triangles of random sizes when intelse~,led as 10 der~,-;bed because of the manner in which the cubes are tilted with respect to a reference plane The inventive ~ ,.h~g cube-comer sl.ee~ e,c can be made in accordance with two techri~uçs In the first technique, a glittering cube-corner ~heetine is made by providing a first cube-corner ~l~fe~t;~ that has the cubes 15 arranged in a convention~l configuration, namely, a non-random orientation, and exposing this ch~eting to heat, pressure, or a co...binalion of both In the second te..~- que, a mold is produced that is a negative of a cube-corner ~heetin~ of the invention This mold may then be used to provide a glittering sheeti~ A method of making glittering sheetine~ is described in U S Patent Application 08/641,129 entitled "Method of Making Glittering Retroreflective .~heeting~" filed on the same day as this application under attorney docket number 52374USAlA
When using the first ter,hn;ql1e~ a cube-corner ~heeti~ is first produced or otherwise obtained which has the cube-corner elemPnts ~-~ged in an ordered cQnfi~.ration There are many patents that ~ se ~l~ect; ~gc that have ordered arrays of cube-corner ~le ~,e~ see, for example, U S Patents 5,236,751, 5,189,S53, 5,175,030, 5,138,488, 5,117,304, 4,938,563, 4,775,219, 4,668,558, 4,601,861, 4,588,258, 4,576,850, 4,555,161, 4,332,847, 4,202,600, 3,992,080, 3,935,359, 3,924,929, 3,811,983, 3,810,804, 3,689,346, 3,684,348, and 3,450,459 Ordered cube-corner arrays may be produced n~cordin~ to a number of known mP,thod~ cll~din~ those disclQsed in the patents cited in the previous sto~nt~nce Other C~.A "les are ~iic~losed in U S. patents: 5,450,235, 4,601,861, 4,486,363, 4,322,847, 4,243,618, 3,811,983, 3,689,346, and in U.S Patent ~rplication 08/472,444 filed June 7, 1995.
Preferably, the cube-corner ek ~ c that are used in the non-randomly S oriented starting ~e~t; .e are made ~om materials that are harder than the materials used in the body portion, particularly the body layer A selection of such materials allows the cube-corner ek...~ ~~s to tilt, without significantly distorting each cube's shape, when the cheetine is exposed to certain anluullts of heat and/or pre~ ,e The heat, plessure, or both that are applied to the 10 cheeting should be sllfficipnt to alter the array significantly from its ordered configuration With a very soft body layer, pressure alone, that is, pres;,.lle above ~tmospheric, or heat alone, namely, heat greater than the sofl[ening tempet~t~lre may be suffiriPnt to change the array from an ordered configuration A Hix N-800 l~nin~tor has a first pressure-applying surface 72 that is made of metal and that may be heated to te"-p_talures as high as 500 ~F The second pressure-applying surface 74 iS an ~ k~(ed rubber mat In ope.~lion, two layers of release paper 7C may optionally be disposed b~h~een the surfaces 72 and 74 and the cube-corner ~heet;~J> 10 A carrier 78 (such as made from 20 polyester) may be disposed on the cube-corner cheeting's front surface 51 Carrier 78 iS a byproduct of the process used to produce cheeting 10 (see, for example, U S Patent Application 08/472,444 at the riicc~csion describing its FIG. 4, where the carrier is ,epresenled by numeral 28) and may optionally remain thereon until after the cube-corner ~1&-"~;"1~5 have been rearranged from25 exposure to heat and/or p.e~ e.
When the ordered~ non-glitl~ii,g cube-corner 5l~ee~ g and optional release paper 76 are all~h~ed in the heat l~tnin~tion m~~hine as shown in FIG
8, the machine is activated so that the pressur~-applying surfaces 72 and 74 move toward each other and hold the ordered cube-corner cheeting at a desired 30 te.llp&-lall~re and p,es;,.lre for a predetc.l"i.-cd time If desired, the lower release paper 76 in FIG 11 may be omitted and the pattern or image of the W O g7141462 PCT~US96/13146 lower, lmhP~ted surface 74 of the heat l~ e --hine may be llan~r~ ed to the ,~lr~lenective sheeting in a glittering pattern. In lieu of a l~ g ;ne, a vacuum former -- such as a ScotchliteTM Heat Lamp Applicator available from Dayco Industries, Inc., Miles, Michigan; P.M. Black Co., 5 Stillwater, Mil-l)çsol~; and Co.~e.ling Technologies, Inc., Goodard, Kansas -- may be used.
A cube-corner l~t~o,~;lle~;li.~e ~l.e~ g that has hard cubes and a softer body layer is tiicc~osed in U.S. Patent No. 5,450,235 to Smith et al. As des~lil,ed in this patent, the body portion incl~des a body layer that co.~ ..c a 10 light ~ is-il,le polymeric material that has an elastic mo~ ls less than 7 x 108 Pascals. The cube-corner ek ..~ , on the other hand, contain a light ~m~ cL:l)le polymeric material that has an elastic modulus greater than 16 x 108 Pascals. U.S. Patent Application Serial No. 08/472,444 also discloses a number of materials that may be used to produce cube-comer shPeti~c in accordance with this invention. This patent application specifies that the elastic modulus of the cube-corner elements is at least 1 x 107 Pascals greater than theelastic modvllJc of the body layer and that its cube-corner elements may be made from materials that have an elastic modulus greater than about 2.0 x 108 Pascals (preferably greater than about 25 x 1 o8 Pascals) and that the body layer or overlay may be made from materials that preferably have an elastic mod--l--c less than about 13 x 108 Pascals. When a cube-corner ~sheeting made from materials of those dçsienstecl elastic modulus values is exposed to certain ~mo~ ntc of heat and pressure, the body layer softens, allowing the cubes to move in l~onse to the pressure and thus become tilted relative to the sheet;.~g's front surface. When using such a construction, the land layer (56, FIG. 7) ideally is kept to a minim~ n~cs (for eY~mple, less than ten percent of the cube-corner P4~ P-l1 height), and preferably zero th ~~neCc~ so that the cubes can easily tilt along their base edges. For this sarne reason, it is also pr~rc~led in this invention that the cube-corner rle "P~ are fractured along their base edges as /licclose~ in U.S. Patent Application Serial No. 08/139,914 filed October 20, 1993 and in U.S. Patent Application Serial No. 08/472,444 filed June 7, 1995.
Elastic r.mdu4ls may be d~t~llu,.ed accolJ;ng to stand~di~ed test ASTM D 882-7Sb using Static Weighing Method A with a five inch initial grip 5 s~a~alion~ a one inch sample width, and an inch per minute rate of grip sepa,alor. Under some cirC~mstqnces~ the polymer may be so hard and brittle that it is tiiffirult to use this test to asc.,.lai" the morlullls value precisely ("ltho-l~h it would be readily known that it is greater than a certain value). If the ASTM method is not entirely suitable, another test, known as the 10 "NAnoindçnt~stion Technique" may be en~ployed. This test may be carried out using a ~f~c~u;~ nt-q~tiQn device such as a U~S 2000 available from CSIRO
Division of Applied Physics Tnctitute of Industrial Technologies of Lindfield, New South Wales, Australia. Using this kind of device, penel~lion depth of a Berkovich pyramidal ~is-non~ indent~r having a 65 degree inrln~1ed cone angle 15 is measured as a function of the applied force up to the maximum load. After the m~x;.. --. Ioad has been applied, the material is allowed to relax in an elastic manner against the indenter It is usually ~sss~lmed that the ~ad.e.ll ofthe upper portion of the unloading data is found to be linearly propo, lional toforce. Sneddon's analysis provides a relationship between the ind~nting force 20 and plastic and elastic components of the penel~lion depth (Sneddon I.N. InL
J. Eng Sci. 3, pp. 47-57 (1965)). From an examination of Sneddon's equation, the elastic modulus may be recovered in the form E/(1-v~). The calculation uses the equation:
E/(l-v2) = (dF/dhe)Fn,a.cl/(3.3hp",a~tan(~)) 25 where:
v is Poisson's ratio of the sample being tested;
(dF/dhe) is the gradient ofthe upper part ofthe l~nlo,~ing curve;
F~ DC is the mqYimllm applied force;
hp~ is the maximum plastic penetration depth;

~ is the half-inrl~lded cone angle of the Berkovich pyramidal inrlçnter;
and E is the elastic mod~ lc It may be neGe~ y to correlate the results of the nqnoind~ntatiQn technique 5 back to the ASTM m~tl -The amount of heat and/or pressure applied to a cube-corner sl.eel;n~
10 may vary depen~iing on the materials from which the cube-corner ~he~ g is made. It has been d,scovered in this invention that when polymeric materials having an elastic modulus of about 10 x lo8 to 25 x lo8 Pascals are used in the 10 cube-corner ek.~- ~Is 12 (and an optional land layer 16), and a polymeric material having an elastic modulus of about 0.05 x lo8 to 13 x lo8 Pascals is used in the body layer 18, the cube-corner sl.ee~ F preferably, is heated to a te~ e-al~lre of about 300 to 400 ~F (150 to 205 ~C) and that about 7 x 104 to 4.5 x 105 Pascals (10 to 60 psi) of pressure are applied to the article. Using 15 polymers that have a relatively high elastic modulus, for ~A~,..ple, greater than 16x 108 Pascals, the geo...~,.-y of each cube, namely, its internal dihedral angles, are generally l"~ ed to within a couple of degrees.
In FIG. 9, a continlloll~ method is shown for applying heat and/or pressure to a co--./e-n;on~l .$l~cet;ng 10 to produce a glittering sheetine 60. In 20 this method, $heel;~ 10, having the optional carrier film 78 disposed thereon, is fed through the nip forrned by rolls 77 and 77'. As shown, cube-corner ele~ 12 are in a non-random, ordered configuration before being exposed to the heat and/or pres~ule from rolls 77 and 77', but after exiting the rolls they are randornly tilted, and the dihedral angles formed bel~cel1 ndjacent cube-25 corner elc ~e ~n~ vary along each groove in the array. The base planes of eachcube-corner Plf~,n.~ also do not reside in the same general plane. The sh~etir~CO that exits the rolls is capable of producing a glille.;ng effect, ~he~eas thecube-comer _heel;.~8 10 that has not been exposed to suffici~nt ~,o~ 1s of heat and/or preSS.IleiSi:~a~?,ble of proclucine such an effiect. The ~nnounts of30 heat and/or p.~,s ,.ne that may be used in this continuous method are similar to those used in the batchwise method for similar starting materials. When using .

CA 022~2613 1998-10-20 W O 97/41462 PCTrUS96113146 heat, either or both rolls 77 and 77' may be heated to the te.~ alllre sl~fficiçnt to alter the cube configuration.
In the second technique for producing a ~ .,l.g cube-corner chr~;.,g a mold may be used that is a negative of a glilLeling cube-corner l-e~t;-~p 5 Such a mold may be made from a glittering cube-corner .~heeting that is produced by the first technique des~,il,ed above. That is, the structured surface or ~c~Q;de of an array of, for example, randomly-tilted cube-corner e~ nl~
can be used as a pattern to produce the mold. This can be accomplished, for e,.~.,ple, by depGs~ g suitable mold material(s) onto the back side of an array 10 of randomly tilted cube-corner pl- -"e~ and allowing the mold material(s) to harden in place. The randomly tilted cube-corner ~heeting that is used as the pattern may then be separated from the newly formed mold. The mold is then capable of prod~c.ing cube-corner .~heetin~ that glitter.
As an alternate method of producing a mold, a diamond tool may be 15 used to fashion the array of cube-corner ~l~ ..c .ls. This may be accompli~hed by, for c,~"~le, using a number of diamond cutting tools, each tool being able to cut the groove which forms one of the desired dihedral angles bel~,en rdj~cPnt cube-corner el~ s Groove depth and angle between ~lilcent cube-corner ele-.. ~1 faces in any single groove is dele",~ ed by the profile of20 the diamond cutting tool that is used to cut the mold material.
To prepare a mold having cube-corner Pl.onnP.nt~ with varying dihedral angles between faces of adjlcent cube-corner Plpments along the groove, it is neceSC~. y to position a ~iz~ond cutting tool capable of cutting the first desi~ed dihedral angle, insert it into the mold material and cut the groove portion that2~ eYtPn~ls from one groove intersection to the ~ ~çnt groove intersection. The tool is then removed from the mold material, and the .1'9 ..onrl cutting tool isreplaced by a tool that is capable of cutting the next desired dihedral angle along the groove. The newly sP4cted tool is then positioned in the ~;~o~ing groove as close as possible to the location where the first cutting tool finished 30 cutting. Cutting the groove is then continued with the second cutting tool until the next groove intersection is l~P-hed~ The second cutting tool is then CA 022~2613 1998-10-20 removed from the mold material and replaced with a cutting tool capable of cutting the third desired dihedral angle in pre~Jalalion for cutting the next groove portion. This process is contin~led for the length of the groove. After co.,.pletior- of the first groove, the next or r1ja-ent groove may be cut in theS same manner using various cutting tools and inc-.,.ne,~tal cuts until the desired number of parallel, or generally parallel, grooves have been completed.
After the first set of grooves is CG ,lete, the diamond cutting tool is a~ cted so that the second set of parallel grooves may be cut such that they intersect with the first set and contain varying dihedral angles bcl~.. en s~jscent 10 cube-corner faces. This process is contin~led until the desired ...l.,.bel of sets of generally par~lel grooves are cut into the mold material.
A mold also may be produced using pin b~n~lling techn~ es Molds msn~lf. ct~red using pin blln~ ng are made by assembling together individual pins that each have an end portion shaped with features of a cube-corner lel.orenective elçm~ont U.S. Patent No. 3,632,695 to Howell and U.S. Patent No. 3,926,402 to Heenan et al. ~licçlQse illustrative c.~amplPs of pin bl~n~lling A plurality of pins are typically fashioned to have an optically active surface on one end d;spGscd at an oblique angle to the longitudinql axis of the pin. The pins are bundled together to form a mold having a structured surface in which 20 the optical surfaces co.,-bine to form the cube-comer el~m~nts. The mold may be used to form glittering sheetin~ or to generate other molds useful in msnufnctl~ring cube-corner sheeting Pins may be arranged such that the dihedral angle be~ ell optical faces of ~ cçnt cube-corner el~ments vary.
One advantage associated with pin bun~ling techniq~s is that the dihedral 25 angle may be varied in a single groove set or in two or more groove sets. Thepins also can be configured such that there are no generally parallel grooves and/or such that the cube-corner el ..fr.ls do not possess base planes that are parallel to one another when the res~lting sheeting is laid flat. Pin b-)n~llingthus can provide additional flexibility in pro~çing glittering sheeting~.
FIG. 10 illustrates a mold 79 that is a negative of an array of cube-corner e~ that co.,.p,ise a glittering .~heeting The mold (also referred to W O 97/41462 PCTrUS96/13146 in the art as a tool) th~eîole may possess three sets of parallel v-shaped grooves 8S, 86, and 87, and the planar faces 81 of adjacFnt cube-corner ..Pn~S80 can form dihedral angles that vary in ~1i",~Y~:on along each groove in the mold's array. For example, in groove 86a, faces 81a and 81b of ~i,ac~nt S cubes 80a and 80b form a tighter dihedral angle a (FIG. S) than faces 81c and 81d of cubes 80c and 80d. The mold may be e~Spnti~l~y the same as the array of cube-corner fl~ ~-cn1s of the invention with the exception of being a negaLive thereof, and since it may not need to t,a.)s.nll light or be col~l".able, it may be made from an opaque material that is relatively inflF~Yible, for example, metal.A mold useful for producing glittering cheeting~ of the invention is described in U.S. Patent Application 08/640,383 entitled "Mold for Producing Glittering Cube-Corner Retroreflective .Sheet;ngc" filed on the same day as this application under attorney docket number 52471USA5A.
FIG. 11 s~-he~9t;C~lly shows how a structured article that is capable of glittering may be formed from a mold 79 of the invention. The method inrl~dçs an apparatus, shown generally as 90, for casting and curing composite sheeting 60. As shown, body layer S8 is drawn from a roll 92 to a nip roller 93 such as a rubber coated roller. At roller 93, the body layer 58 contacts a s -i~able resin formulation 94 previously applied to a patterned mold 79 on a roll 95 through a coating die 96. The excess resin 94 ~Yten-lin~e above the cube-corner Flr....-."c 80 may be ...;~ ed by setting nip roller 93 to a width setting that is effectively less than the height of the cube-corner forming Fl.."~ c of mold 79. In this fashion, meçh~nical forces at the interface b~ e~,n nip roller 93 and mold 79 ensure that a ~ -,.. amount of resin 94 25 eYt~.nds above the mold el~-..enls 80. DepF..--ling on its flexibility, the body layer 58 may be optionally supported with a suitable carrier film 78 that provides structural and n~cllAn .c ~ eglily to the body layer 58 during casting and curing, and which is sll;yped from the body layer 58 after the ~hee~ is removed from the mold 79 at roll 98. Use of a carrier film 78iS pre~led for 30 low modulus body layers 58.

W O97/41462 PCT~US96/13146 The method shown in FIG. 11 may be altered such that the resin 94 is applied to the body layer 58 first rather than being first deposited on the mold79. This embodiment for a contin~lous process is Ai~cucsed in U.S. Patent ~rplic~tiQn 08t472,444 with re~.ence to its figure 5.
As shown in FIG. 11, the resin comro~itiQn that forms the array of cube-corner ~le-~r-~l C can be cured in one or more steps. Radiation sources 9g expose the resin to actinic radiation, such as ultraviolet light or visible light, depen~ling upon the nature of the resin, in a primary curing step. The actinic radiation from source 99 irradiates the resin through the layer 58 -- thus 10 impo~ g a requ;re."enl that the body layer S8 ~ S~II;l radiation to allow curing to occur. Alternatively, curing can be peJÇo,...ed by irradiation throughthe mold 79 -- if the mold used is s~fficie1ltly Lf~-spa.enl to ~ 5--llL the sPlected radiation. Curing through both the tool and the body layer also may be carried out.
The p.;.l.a~y curing may cGmpl~tçly cure the cube-corner rll,n~e~-ls or may partially cure the resin composition to a degree sl.ffici~Pnt to produce dimensionally stable cube-comer ele.~e~lc that no longer require the support of the mold 79. The shecl;~ 60 can then be removed from the mold 79, exposing the ~heeting's cube-corner ehP,mP~ts 30. One or more second~ry curing 20 treatments 100, selected dep~ B upon the nature of the resin, can then be applied to fully cure the array of cube-corner Plennents and strenethPn the bondbelvleen the array of cube-corner e4-~.e ls and the body layer. This bifurcated curing approach can permit opLi-luLed processing and materials selection. For ;~s~ ce a $he~l;ng made from a body layer that contains an ultraviolet 25 absorber (to impart greater durability and weathering ability) can be made byapplying a primary curing ll~ nl~v ~l of visible light through the light-.s~ s,ib1e body layer, and then removing the shPeting from the mold 79 atroll 98 and applying a second curing ll~~l...e.~ 100 of ultraviolet radiation to the &.~},Gsed cube-comer ele..e lls. Such a bifurcated appr~sch may permit 30 faster overall prod~ction CA 022~2613 1998-10-20 The eY~tent of the second curing step de~ c on a number of variables, among them the rate of feed-through of the materials, the con.pGsilion of the resin, the nature of any cros~ in~ initiators used in the resin formulation, andthe geon,~t-y of the mold. In general, faster feed rates increase the likelihood5 that more than one curing step is needed. Selection of curing l~ça~...e..1c depends in large part on the specific resin chosen for produ~ing the cube-cornerelement~ Electron beam curing could be used, for ~"~anl~,le, in lieu actinic radiation.
When using a mold to prepare glilleling l~t~oltnective shçe~
10 thermal curing materials may be used. In this case, the mold is heated to a t~.l,p~ re s~lffi~ ient to cause develop..le.ll of enough cohesion in the newly formed glillel i"g cube-corner material to allow it to be removed from the mold without r~n~agjn~ the physical or optical prope,lies of the newly formed ~ e~,l;ng The sf1e~,ted t~,."pe.al-lre is a function of the therrnal curing resin.
15 Thermal curing may be achieved, for . Y~mple, by heating the resin, by heating the mold, or by heating the glittering ~he~ p by indirect means. Col"b;l-dtions of these m~ti otls also may be used. Indirect heating inr~des metho~s such as heating with lamps, infrared or other heat source fil~m~nt~, or any other convenient m.othof1 The mold may also be housed in an oven or other 20 environl"ellt that is ~ ned at the temperature required by the therrnal curing resin setecte~l A~er the glilleling rello~ ective ~heetin~ has been removed from the mold, it may be further treated by exposure to heat from an oven or other heated em~i~o....-~ ~ Such subsequçnt heat lle~..e~ may adjust the sh~eting's 25 physical or other p.ope.lies to some desired state, to co.nl:lete reactive processes in the she~ g or to remove volatile s~ -ces such as solvents, unreacted materials, or by-products of the thermal curing system.
Thermal curing resins may be applied to the mold as sol~tiQns or as neat resin formulations. Resins also may be either reactively extruded or extruded in30 the molten state onto the mold. Metho~s of thermal curing after app1ying the . ...
.....

W O 97/41462 PCTrUS96113146 resins to the mold, and any subseqllent exposure ofthe ~l-ee~ing to heat, may bedone i~depcf~1ent of applying the thermal curing resin to the mold.
An advantage of glittering shf~line made from thermal curing materials in a mold is that both the cube-corner ~ 5 30 (FIG. 3) and body portion 5 54 (FIG. S) may be made from the same subsl ~ce, which may be applied to the mold in a single ope~alion. A co~-~e~-lçnce of this construction is that the~$he~,t;ng may exhibit uniru--,. materials and propcllies throughout the .Cl~eeting A further advantage is that constructions of this type do not require a separatebody layer to be applied as illustrated in FIG. 11.
In addition to curing Ir~n~e.~ls, sheefin~ may also be heat treated after it is removed from the mold. ~in~ serves to relax stresses that may have developed in the body layer or in the cube-corner Ple~-f ~IS, and to drive off unreacted moieties and byproducts. Typically, the ~heeting is heated to an elevated te~ JeGlal~lre~ for example, above the polymer's glass tr~nqition 15 temperature(s).
In lieu of cast-and-cure methods, glillG~ing sheeting~ of the invention may also be produced by embossing a polymeric sheet over a mold that possesses cube-corner ek....~ s a~ ged in accordance with the present invention. E~ tvles of embossing methods are disclosed in United States Patents: 5,272,562, 5,213,872, and 4,601,861.
Glittering ~heeti~.~ that display images also may be produced in accordance with the present invention.
FIG. 12 illustrates a glittering article 101 that displays the image "ABC". The image 102 in this case is cha, t srized by a glill~.i,-g area, while the background 103 is charavlelizeGd by a non-gliue.i,lg area. As used herein, an "image" may be any co.nbi~ ion of alph~ eric characters or other indicia that stands out in contrast to the bac~round. Glittering imaged articles, like article 101, may be produced as descli~ed below.
Imaged glittering cl~elinp. may be produced in a first embodiment by 30 h~sv. lig a material in the shape of the desired image into the assG.l,bly shown in FIG. 8. Thin material in the shape of the desired image, such as an insert . . .

CA 022~2613 1998-10-20 W O 97/41462 PCT~US96113146 104 (104 refers generically to any s~ it~ble insert inclu~li~ 104a and 104b of FIGs. 16a and 16b) in ~IG. 8 can be placed between the cube-corner reflective e4rn~nts 30 and the optional lower release liner 76. The image m~t~ s may be a polymeric film made frorn, for example, polyester. The insert 104 may 5 comprise a large, smooth sheet firom which the desired image has been cut, fo...f.,.g a negative image in the insert. Sul~tin~ this arrangement to procescing con~i1;ons of elevated te.lli)elalult; and/or p~es~lfe results in a ~l.ce~in~ that bears the desired image as a glittering portion on a bac~,ound that is subst~ntislly not glittering or that has a low level of glittering. When the 10 insert 104 is in the size and shape ofthe desired image, suhjecting the cheeting 10 to elevated tenl~Jc~al~lre and/or pressure results in sheet material that bears a non-glittering image co,.~ yonding to the insert 104 on the glill~.i"g background. A p,~fe..ed embodiment is without the release liner 76.
An insert 104 can be placed with the image forrning elements in contact 15 with exposed cube-corner PlPm~ntC 30 as shown in FIG. 8, or on the top face of the ordered rel.ol~llective sheeti~ 10 with image forming elen Pntc 106 cont~cting the optional polyester film liner 78 or directly cont~cting the frontsurface 51. Alternatively, an ordered cube-corner .~heeting 10 may be ins~,led in l~.n;~ or 71 with the cube-corner Ple~ 30 facing the heated l~...;..~lQr surface 72, and the front surface 51 (and optional carrier 78) facing an unhP~ted lqnn;~qtQr surface 74. Thus, an image forming insert may be disposed either above or below the sheeting.
In FIG. 13a an image insert 104ais shown that may co--.~-ise a durable ."ale. -' 105 that bears projectionC 106 rising away from the surface of the sheet material 10~. In this embodiment~ the projections 106 form the desired image. An c ,~".~,lc of such a device is a flexographic plhltmg plate. When thistype of image bearing device is placed in the arrangement of FIG. 8 such that the image fo",.ing projections 106 of insert 104a contact the exposed cube-corners and the ass~..bly is subjected to elevated ten.~,~,.dl~lre and/or pressure, 30 a c~ ee~ e is produced that bears a glittering image on a subs~ y non-glittering background.

. . . ~

The degree and extent of glittering may be controlled by the process con-lifion~ For P~ ple, procecsing with a flexographic printing plate for short time periods results in an image that is capable of glittering only at thepoints where projections 106 directly contact the bar~side of the cube-corner S e4 ..~ 30 Non-contact areas remain and sul~ lly not glittering As procçccing time incl~,ases, and as proces.:~lg t~,..lpelal~lre increases, the extent of glill~.;..B, extends away from the contact points of projections 106, and theres~llting image graduaJly cl-~ng~s from (a) glille.ing only at contact points to (b) a glittering image on a glittering bacl~r~,und, to (c) a non-glittering image 10 (where cube-corners have been sub~lanlially pushed out of the contact areas) on glittering background In FIG 13b, an image forning element 104b is shown that may co...p~ise a carrier material 108 on which a heat-~.ar.srt;..able material 110 has been deposited in the shape and size of the desired image For example, heat-Ir~.,~,-able ink 110 may be deposited on a carrier film 108 in the form of the image to be l,~.~..cd. The carrier film 108 bearing the desired image is placed as an insert 104 in a l~min~tor 71 of FIG 8 such that the exposed back side of the cube-corner Ple~ s 30 contacts the image surface 110 on carrier film 108 The a~ r~e~ is subje ed to the processing conditions of 20 elevated te...pc~ re and/or pressure, and the resulting ~heeting bears an image on a glittering bacl~ground The image bearing insert 104 in FIG 8 also may be a large piece of fabric (not shown) or other material bearing an overall pattern or texture In the case of a fabric insert, the image carried by the insert is derived from the25 fabric's confiel-~ation Additionally, the image on the sheetin~ may cGlres~ond to an image cut from the fabric When a fabric type insert is placed in contact with the eA~Gsed back side ofthe cube-corner el~ ls 30 and the a li ~g~
is s~lbje~;ted to elevated tc.l~ ure and/or presswe, the relc..lting cube-cornersheel;~g bears an overall image that is capable of glittering and that exhibits the 30 confi~.ration or texture ofthe fabric Further, the fabric's texture or weave can enhance the glittering effect in the imaged area Coarse fabrics tend to ... ~. .

W O 97/41462 PCTrUS96113146 encourage more glittering. If desired, the lower release paper 76 in FIG. 8 may be removed completely, and the pattem or image of the lower, unhe~ted surface 74 ofthe heat 1z.~ 9~in~ hine may be Iràl1s~lled to the ~hfe~ p in a glilh,ing pattem.
There is broad latitude in prod~lç;~ images by contactin the ordered cube-comer o~etin with an image fomling e~ r--.l The appeal~i~ce of the image depr-~Ac on process co~itions~ the construction from which the imaged glittering Cl~ee~;~8 is made, and on the size, shape, and materials of the imagefomling el~ -ne~ The degree of gliU~ .g in imaged and in no..;...sged areas 10 may be s~lccescfi.lly altered when one or more of these variables is changed.When the image fomling element 104 is, for example, a textured surface such as fabric -- such as a woven polyester mesh -- the glittering effect may be considerably enh nced when col,lpared with the glille,i~ heeting prepared in the ~1 sPnce of such a textured surface. Photomicrographs of sheeting with 15 Pnhqnced ~Gtlc-ing showed a s~b~ lly greater degree of cube-comer el~mPnt reori~"ltalion, inrlll~ing groups of cube-comer elements piled upon each other, than sheetin~ fommed in the ~bsPnr,e of a textured image forming rl/~ It is believed that the enhqnce~ e,ii~g effect is related to the additional reflective paths available to light inridçnt on the piled cube-corner20 rlo -~el-ls. Accol.lh,gly, there is a general range of glittering image forming abilities of the article of the invention which can be achieved by ch~ngjne these or other ~a,;ab'es.
Glittering sheeti~ capable of bearing images also may be pl~pa.ed by the second technique, directly from a mold. Fssrnti~lly any method used to 25 prepare sheetings that display glille,ing images on glittering or a non-gl;llel;ng background or non-glittering images on a glittering b&c~lollnd according to the first technique (FIG. 8) is also ~pplir-~ble to the second teçhniq~le (FIG. 11).
A glittering sheeting that displays an image may be used as a pattern on which mold materials are de~,os;led and/or cured. Removal of the paUellled sheetins~
30 reveals a newly formed mold that bears the image formed on the pattérn material. Use of such molds produces sheeting that is capable of glittering and still cc,..lAil.c the image applied to the original ~l ev~ g from which the moldwas prepared. Images printed, deposited, or formed directly on the exposed back side of the cube-corner ele~ l5 by various terhniques may be fgithfi~ly replir,s-ted in the mold making process. Images placed on the body layer 58 5 may also end up being replir~sted in the mold making process.
For some applicatiQr,~ particularly when produring a glittering article accGr~ng to the first technique (that is, using heat and/or p,cs~ure), the polymeric materials that are h..plo~cd in the cube-corner el ~.le ~lS plef~ bly are hard and rigid. The polymeric materials may be, for CA~l.~ le, thermoplastic10 or crosslinkable resins. The elastic mod~llus of such polymers pre~el bly is greater than about 10 x 108 Pascals, and more preferably is greater than about 13 x lOg Pascals.
FY~srnpl~s of thermoplastic polymers that may be used in the cube-corner elemPntc include acrylic polymers such as poly(methyl meth~crylate);
15 polycarbonates; celll~losics such as cellulose acetate, cellulose (acetate-co-butyrate), ce~ ose nitrate; e~u~ies~ polyurethsnes; polyesters such as poly(butylene tereph~ te), poly(ethylene ter~l.~halqte); fluoropolymers such as poly(chlorofluoroethylene), poly(vinylidene fluororide); polyvinyl halides such as poly(vinyl chloride) or poly(vinylidene chloride); polyamides such as 20 poly(caprol~ctsm), poly(amino caproic acid), poly(heY-s-~nethylene diamine-co-adipic acid), poly(amide-co-imide), and poly(ester-co-imide); polyetherketones;
poly(etherimide); polyolefins such as poly(methylpentene); poly(phenylene ether); poly(phenylene sulfide); poly(styrene) and poly(styrene) copolymers such as poly(st)~l e.lc-co-acrylonitrile), poly(styrene-cû-acrylonil, ilc-co-25 butadiene); polysulfone; silicone modified polymers (i.e., polymers that containa small weight percent (less than 10 weight percent) of silicone) such as silicone polyarnide and silicone polyca.l,onale, fluorine tnodified polymers such as perfluoropoly(ethyleneterephthslste); and n.i~lules of the above polymers such as a poly(ester) and poly(ca,l,onale) blend, and a fluoropolymer and 30 acrylic polymer blend.

W O 97/41462 PCTAJS96tl3146 The cube-corner el~, . .P ~1 ~ also may be made from reactive resin systems that are capable of being crosslinked by a free radical polyl..eliLalion mechsrlicm by eYros~lre to actinic radiation. Additionally, these materials may be pol~llleli~ed by thermal means using a thermal initiator such as benzoyl S peroxide. Radiation-it~;tisted cationically polyl"~,.i,~ble resins also may be used.
Reactive resins suitable for forming the cube-corner el~ ne~ may be blends of a photoi~ or and at least one co...pound bearing an acrylate group.
~lerelably the resin blend co"~Ai"c a ~ifilnctional or polyfunctional cG...pound10 to ensure formation of a crosslinked polymeric network when irradiated.
F.--lmp1es of resins that are capable of being polymerized by a free radical ~ h~n.~ .. include: acrylic-based resins derived from epoxies, polyesters, polyell.el~, and uletll~n~s, ethylenically unsaturated compounds;
aminoplast derivatives having at least one pendanl acrylate group; isocyanate 15 derivatives having at least one pendant acrylate group; epoxy resins other than acrylated epoxies; and mixtures and con~inalions thereof. The term acrylate is used here to encor..pass both acrylates and methacrylates. U. S . Patent 4,576,850 to Martens discloses e,.a,~ les of crosslinked resins that may be usedin the cube-corner ~lem ~ of glittering ~ ol enective sheeting Ethylenically unsdlu~aled resins include both monomeric and polymeric compounds that contain atoms of carbon, hydrogen and oxygen, and optionally nitrogen, sulfur and the halogens. Oxygen or nitrogen atoms or both are generally present in ether, ester, ur~thane, amide and urea groups.
Ethylenically unsaturated compounds preferably have a molecular weight of less than about 4,000 and p-efer~bly are esters made from the reaction of compounds co..~ . ~l;rh~tic monohydroxy groups or aliphatic polyl.~d.v~y groups and uns~lulaled carboxylic acids, such as acrylic acid, meth~~rylic acid,haconic acid, ~i.oto- acid, isocrotonic acid, maleic acid, and the like.
Some examples of compounds having an acrylic or meth~crylic group 30 are listed below. The listed compounds are illustrative and not limiting (I) Monoru .~,l;onal co-,-pc-~nds:

ethylacrylate, n-butylacrylate, isobulylacrylate~ 2-ethylhexylacrylate, n-hexylacrylate, n-octylacrylate, isooctylacrylate, isobornyl acrylate, tetrahydrofurfuryl acrylate, 2-phenoAyethyl acrylate, N,N-dimethylacrylamide;
(2) D ~lnctionsl comrolln~C
5 1,4-but~n~iol diacrylate, 1,6-L ~ -~;ol diacrylate, neop.,..lylglycol diacrylate, ethylene glycol diacrylate, triethyleneglycol diacrylate, and tetraethylene glycol diacrylate, and diethylene glycol diacrylate;
(3) PolyfilrlctiQn-q-l co..,pounds:
lolp~opane triacrylate, glyceroltriacrylate, pentaerythritol triacrylate, pent&e.yllll;lol tetraacrylate, and tris(2-acryloyloxyethyl)isocyanurate Some It;prese-~alive ~ ~ of other ethylenically unsaturated compounds and resins include styrene, divinyll,~ -7Pl-e, vinyl toluene, N-vinyl pyrrolidone, N-vinyl caprolactam, monoallyl, polyallyl, and polymethallyl esterssuch as diallyl phthqlste and diallyl a lir-s-tç, and amides of carboxylic acids such as and N,N-diallyladipamide Examples of photopol~ c~ization initiators that may be blended with the acrylic compounds include the following illustrative initiators benzyl, methyl o-ben7~q~te, ben7sin, ben_oin ethyl ether, benzoin isoprol)yl ether, benzoin isobutyl ether, etc, benzopkensne/tertiary amine, acetophenones such as 2,2-diethoA~ cetophenone, benzyl methyl ketal, l-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl- 1 -phen~lpropan- 1 -one, 1 -(4-isopro~yll)henyl)-2-hydroxy-2-meth~lp~opan- 1 -one, 2-benzyl-2-N,N-dimethylamino- 1 -(4-morphol-inophenyl)-l-but~rlone, (2,4,6-~ etl,~lbenzoyl)diphenylphosphine oxide 2-methyl-1-4-(-~ lh~llh o)phenyl-2-morpholino-1-plopanone, bis(2~6-~ thoAybenzoyl)-2~4~4-lli~nell~lpcl~lylrhosrhine oxide, et cetera These compounds may be used individually or in co".~i..alion.
C"~ic-- ~"y pol~.l.e.i~ble materials include but are not limited to materials co~ g epoxy and vinyl ether filr ction~l groups These systems are photoiniti~ted by onium salt inilialo~ such as l.i~,yls~lfonium, and 30 diaryliodonium salts ., CA 022~2613 1998-10-20 Plc;fe~led polymers for use in the cube-corner ek~"-,ls include poly(c~l,on~le), poly(methy' ' acrylate), poly(ethylene terephthqlqte), aliphatic polyur~l.at-es and crosslinked acrylates such as multi-functional acrylates or acrylated epoxies, acrylated polyesters, and acrylated urethanes bl~nded with mono- and multi-fi~n~---' monomers. These polymers are pre~ d for one or more of the following reasons: therrnal stability, envilu~ eQt~l stability, clarity, release from the tooling or mold, or high receptivity for receiving a reflective coating The polymeric l"aleli~ls employed in a land layer, if one is present, may be the same as the polymers that are employed in the cube-corner elements.
The optional land layer pr~felably has a smooth interface with the cubes and the body layer. When present, the land layer, in most instances, is integral with the cube-corner elem~nt~. By "integral" is meant the land and cubes are formed from a single polymeric material -- not two d~ ;l e,~l polymeric layers subsequently united together. Although the land layer desirably is made of a polymer similar to that of the cubes, the land layer also may be made from a softer polymer such as those described above for use in the body layer.
The body layer may comprise a low elastic modulus polymer for easy b~n-lin~ curling, flexing, col~rl"i~lg, or stretchine and for allowing the cube-corner elem~onts to become reoriented when an ordered array is exposed to heat and pl~ss.~le. The elastic modulus may be less than 5 x 108 Pascals, and may also be less than 3 x 108 Pascals. A low elastic modulus body layer, however, is not always required. If it is desired to make glittering sheetine~ that are less flexible, ~l~e~ s with body layer having higher elastic modulus may be used, such as rigid vinyl with elastic mod~llus about 21 to 34 x 108 Pa. Generally, the polyrners of the body layer have a glass transition tel..~)el al~lre that is less than 50 ~C. The polymer plere.ably is such that the polymeric material retains its physical inleg,ily under the conditions to which it is exposed during processi-l~
The polyrner desirably has a Vicat so~ening tel~ c~all~re that is greater than 30 50~C. The body layer may be either a single layer or a multi-layer col..pol1en as desired Examples of polymers that may be employed in the body layer include fluorinated polymers such as poly(chlorotrifluoroethylene), for example Kel-F800TM available from 3M, St Paul, Mi~u~e~ola; poly(tetrafluoroethylene-co-hex~fl~orol)ropylene), for example Exac FEPIM available from Norton Pe.~.",dnce, Bl~.,ploll, M~s~ch~setts; poly(tetrafluoroethylene-co-perfluoro(alkyl)vinylether), for example, Exac PEATM also available from Norton P~,.ru""ance; and poly(vinylidene fluoride-co-h~Y~fluQlupropylene), for e,.~,ple, Kynar Flex-2800TM available from Pennwalt Co".o, alion, Ph;~ elrhia, Pennsylvania;
ionomeric ethylene copolymers such as: poly(ethylene-co-meth~rylic acid) with sodium or zinc ions such as Surlyn-8920TM and Surlyn-99101M
available from E I. duPont Nemours, Wilmington, Delaware;
low density polyethylenes such as: low density polyethylene; linear low density polyethylene; and very low density polyethylene;
pl~ti~i7~d vinyl halide polymers such as plaslic;~ed poly(vinyl chloride);
non- or l-nr1~ctici7ed rigid vinyl polymers such as Pe~ intTM PR 180 from Klockner Pçnt~rl~t of America, Inc, Gordonsville, Virginia;
polyethylene copolymers incluriing acid functional polymers such as poly(ethylene-co-acrylic acid) and poly(ethylene-co-meth~~rylic acid) poly(ethylene-co-maleic acid), and poly(ethylene-co-fumaric acid); acrylic functional polymers such as poly(ethylene-co-alkylacrylates) where the alkyl group is methyl, ethyl, propyl, butyl, et cetera, or CH3(CH2)n- where n is 0-12,and poly(ethylene-co-vinylacetate); and ~lirh~tiC and aromatic polyurethanes derived from the following monollle.~ (1)-(3): (1) diisocyanates such as dicyclohexylmethane-4,4'-diisocyanate, isophorone diisocyanate, 1,6-h~ 1hylene diisocyanate, cyclohexyl diisocyanate, diphenylmeth~ne diisocyanate, and co...bh~dlions of 30 these diisocyanates, (2) polydiols such as polypentyle~ ir~te glycol, polytt;l~alll~lhyl~ne ether glycol, polyethylene glycol, polycaprolactone diol, ., . . ~

W O 97141462 PCTAUS96tl3146 poly-1,2-butylene oxide glycol, and combinalions of these polydiols, and (3) chain eYtpndçrs such as but~ne~liol or hPY~neAiol. Commercially available urethane polymers include: PN-04, or 3429 from Morton International Inc., Seabrook, New ~ .s~;~c, or X~107 from B.F. Goodrich Company, 5 Cleveland, Ohio.
Col..b;~ ;ons ofthe above polymers also may be employed in the body layer of the body portion. Preferred polymers for the body layer include: the ethylene copolymers that contain units that contain carboxyl groups or esters of ca.l,u~ylic acids such as poly(ethylene-co-acrylic acid), poly(ethylene-co-10 mPth~crylic acid), poly(ethylene-co-vinyl~Get~te); the iono---e.ic ethylene copolymers; pl~ctici7ed poly(vinyl chloride); and the aliph~tic urell~Anes Thesepolymers are plefc~l~,d for one or more of the following reasons: suitable ~--e~ l plupellies~ good adhesion to the land layer or cube-corner Pl~ ..c ~s, clarity, and en~,ho~ l stability.
Selection of certain resins for the cube-comer ~l~m~nts and the body layer may result in an intel~, nc l.aling network after curing. Particular co...binalions of resins for cube-corner elements and body layer can be readily screened for pench~lion by application of a quantity of the cube-corner resin tothe body layer. Priola, A., Go7.7elino, G., and Ferrero, F., Proceedings of the 20 ~7II Internafional Conference in Organic Coatings Science and Technolof~y, Athens, Greece, July 7-11, 1987, pp. 308-18, discloses a watch glass test suitable for this purpose. See also U.S. Patent Application 07/472,444 filed June 7, 1995.
In an embodiment that conlains polycall,ol,a~e cube-corner elemçnt~
25 and/or a polycarbonate land layer and a body layer that co~ nC a polyethylenecopolymer such as poly(ethylene-co-(meth)acrylic acid), poly(ethylene-co-vinyl~c~te) or poly(ethylene-co-acrylate), the interfacial adhesion bc;l~eel- the body layer and the land layer or cube-comer elements can be improved by placing a thin tie-layer (not shown) therebetween. The tie-layer can be applied 30 on the body layer before l~ cl;ng the body layer to the land layer or to the cube-corner e~ The tie-layer can be applied as a thin coating using, for CA 022~2613 1998-10-20 f ~ .le: an ~1irhqtic polylll elhane in organic solution, for eY~mp'e Perm~-th-~ e~M U26-248 solution, available from Perm~th~nç Company, Peabody, ~-s~~hl~settc; Q-thaneTM QC-4820 available from K.J. Quinn and Co., Inc., Seabrook New ~ s' :-e; an ~lirh~tic polyurethane waterborne disp~,.s;on, for example NeoRezTM R-940, R-9409, R-960, R-962, R-967, and R-972, svailable from ICI Resins US, Wilmington, ~ achucettc; an acrylic polymer water borne d;sye~;on, for eAanlple, NeoCrylTM A-601, A-612, A-614, A-621, and A-6092, available from ICI Resins US, Wilmington, ~Cc~hllcett~; or an alkyl acrylate and ~lirhqtic ut~lhane copolymer water borne dispersion, for example NeoPacTM R-9000, available from ICI Resins US, Wilmin~on, M~c~ch~setts. In addition, an electrical discharge method, such as a corona or plasma l~ , can be used to further improve the adhesion of tie-layer to the body layer or the tie-layer to the land layer or to the cube-corner elçnlpnts Cube-corner cheetinec that are produced accol ~lh~g to the second teç~mique may be made from polymers ~liccucsed above as being applicable in the first technigue. That is, the cube-corner f~"~F .ls may comprise harder, or high m~ldulus polymer(s) and the body portion may cGIll~lise softer, or lower modulus polymer(s). In ~ itio~ to these materials, cube-corner cheetingc that colllpl;se harder body layer polymers such as polyesters or polycarbonates may also be made by the second teçhni~ue. Further, when cheetine is made by the second techn;que the chemistry applicable to the cube-corner elements is broader than in the first technique, that is, cube-corner Plcn~el~ls may comprise either hard or soft polymers. U.S. Patent ~pplication 08/625,857 to Wilson et al. (filed April 1, 1996) diccloses c,. ples of polymers that may be used in thecube-corner p~ r..~l C of the present invention.
When an article of the invention is prepared according to the second technique, sofL polymers -- that is, polymers having an elastic rnodl~hls less than 10x108 Pascals -- may be used to produce the cube-corner ek..(!-ts in 30 glittering cheeting In the second technique, the cube-corner ele ..el-l~ are not sub,e ~:ed to the heat and/or pressure con~1itiQnS of the batchwise or contin~JouC

W O 97/41462 PCT~US96113146 processes of the first technique because the cube-corner ele.nent orie~ ;ollc are dete,.".ned by the confi~lration of the mold. That is, glittering sheeting~
made by the second teçhn:~ue can produce cube-corner cle..-e~l oriçnt~ir~nc of the invention directly from the mold. Distortion of the cube-corner ek ..~ .~s 5 th~ ,fole is much less a concern, and it is possible to produce glittering ~heetir~s that co...l.. ;.ce only, or consist ess~ lly of, soft polyrners throughout the construction.
F.Yqn, le of soft polymers that can be used to make glittering cube-corner ~I.~e~;~ using the second technique include flexible poly(vinyl halides) 10 such as poly(vinyl chloride), poly(vinylidene chloride); PVC-ABS; reactive and nonreactive vinyl resins; vinyl acrylates; mixtures of vinyl acrylates with acrylated epoxies; polysiloxanes; alkylalkoxysilanes; acrylated polysiloxanes;
polyurelhAI~es; acrylated ureth-q-nes; polyesters; acrylated polyesters; polyethers;
acrylated polyelh~, acrylated oils; poly(tetrafluoroethylene);
15 poly(fluoroethylene-co-fluoropl opylene); poly(ethylene-co-tetrafiuoroethylene); polybutylene; polybutarii~ne; poly(methylpentene);
polyethylenes such as low density, high density, and linear low density;
poly(ethylene-co-vinyl acetate); poly(ethylene-co-ethyl acrylate).
These polymers can be used either alone or may be blended together.
20 Further, they can be blended with those described for the first teçhn:que to give glittering cube-corner rel,orellective ~heeting via the second technique. Tn addition, ~qdj--sti~ the crosslink density of the reactive polymers or blends listed for the first technique can also yield soft materials. The plOpt;l ties of the no~ P~tive polymers can be adjusted by c~ gi..g the conce~ltlalion bf 25 additives such as p!q~ti~ i7er, or by selectinn of dirre~ ~nt polymer grades.Colorants, UV abso~l~e,s, light stabili,t;,s, free radical scavengers or antioxiclqnt~, processing aids such as antiblocking agents, releq~ing agents, lubricants, and other additives may be added to the body portion or cube-corner elem~ont~ The p. rticular colorant s~lected of course, dep~n-l~ on the 30 desired color of the sheeting Colorants typically are added at about 0.01 to 1 weight percent. W absorbers typically are added at about 0.5 to 2.0 weight .... .. .

percent. FY~nlrl~s of W absorbers include derivatives of bel~olliazole such as TinuvinTM 327, 328, 900, 1130, Tinuvin-PW, available from Ciba-Geigy Corporation, Ardsley, New York; chemical derivatives of benzophonone such as UvinullM-M40, 408, D-50, available from BASF Corporation, Clifton, New 5 Jersey, or CyasorbTM W531 from Cytech Industries, West Patterson, New Jersey; SyntaselM 230, 800, 1200 available from Neville-Synthese Olg~lLCS7 Inc., F~ s).ul~ , Pennsylvania; or chemie~l derivatives of diphenylacrylate suchas UvinulT~-N35, 539, also available from BASF Coll,o,~lion of Cli~on, New Jersey. Light stabilizers that may be used include hindered amines, which are 10 typically used at about 0.5 to 2.0 weight percent. F.Y~mp'~s of hindered amine light stabilize~s include TinuvinlM-144, 292, 622, 770, and Chim~ssorbTM-944 all available from the Ciba-Geigy Corp., Ardsley, New York. Free radical scavengers or antioxi(~nts may be used, typically, at about 0.01 to 0.5 weight percent. Suitable antio~idallls include hindered phenolic resins such as IrganoxTM-1010, 1076, 1035, or MD-1024, or IrgafosTM-168, available from the Ciba-Geigy Corp., Ardsley, New York. Small amount of other proces.cine aids, typically no more than one weight percent of the polymer resins, may be added to improve the resin's processibility. Useful procçssine aids include fatty acid esters, or fatty acid amides available from Glyco Inc., Norwalk, 20 Connecticut, metallic stearates available from Henkel Corp., Hoboken, New Jersey, or Wax EIM available from Hoechst Celanese Corporation, Somerville, New Jersey. Flame retardants -- such as Tetrabromo Bisphenol A Diacrylate Monomer, SR640, from Sauromer Company, Inc., Exton, Pennsylvania, or Tricresyl phosphate, KronitexTM TCP, from FMC Col~oralion, Phil~delrh;a, 25 Pennsylvania -- a1so may be added to the polymeric materials of the inventivesheeting to opti.n.Le its overall propellies, as well as the plopc~ es of the article to which it may be a~t~-hed Flexible glittering sh~etine may be used on or as irregular surfaces as decorative articles. For ~ lllple, the cheetine may be placed on or used as 30 small decorative items such as: ribbons, bows, shred, tinsel; w~pping and 1~ r c~eing items such as tissue, bags, wrapping paper; greeting cards;

. .

W O 97/41462 rCTAUS96/13146 G~ 5, home deco.alions such as wall coverings and window decorations;
fabric; decorations or ol..~ enlh~;ons for toys; or may be a conspicuity articlefor use on a sidewall of truck trailer, a flexible article of clothing, a warning flag, a light wands, et cetera. Sheetin~s of the invention also may be embossed 5 or otherwise ~dPpted into three ~ .-P .~ onal structures as taught in U.S. Patent Application 08/641,126 entitled "Formed Ultra-Flexible Retroreflective Cube-Corner Composite ~heeting with Target Optical Flope,lies and Method for Making Same" (attorney docket l~umber 52477USA3A) filed on the same day as this patent application.
The invention is further illustrated in detail by the following Examples.
While the FY~.I.IeS serve this purpose, it should be understood that the particular ingredients used as well as other conditions and details are not to be construed in a manner that would unduly lirnit the invention.

EXAMPLES
Exam~le 1 - Glittenng, No. ILl~ cJlect~ve S~ t -g from Electroformed Tool Glittering cube-corner retroreflective sheeting -- prepared as described in Example lh of U.S. Patent Application Serial No. 08/640,326 -- entitled 20 "Glittering Cube-Corner Retroreflective Sheeting" (attorney docket number 52373USA3A) filed on the same day as this application -- was positioned on a ~s~ine support and fixed in place with double-sided adhesive tape. A silver metal coating was provided over the entire surface by electroless deposition forrendering the glittering cube-corner lel-orellecting sheetine conductive for 25 ele-;l.opl~il.g. The reC~lting assc.-,bly was immersed in a nickel s -lf~rnate bath co..~ g 16 ounces/gallon (120 g/L) of nickel; 0.5 ounces/gallon (3.7g/L) of nickel bromide; and 4.0 ounces/gallon (30g/L) of boric acid. The rpm~inllpr Of the plating bath was filled with ~listilled water. A quantity of S-nickel anode pellets were co.~ ed within a fit~nium basket that was s~spended in the 30 plating bath. A woven polypropylene bag was provided surrounding the tit~ni~lm basket within the plating bath for l-~pil.~ particlll~es. The plating bath was continllo~l~ly filtered through a 5 micrometer filter. The te~ alu~e ofthe bath was ...~ A;~.~d at 90 ~F (32 ~C) and a pH of 4.0 was ...a~ ed in the plating bath solution. A current density of 20 amps per square foot (215 amp/square meter) was applied to the system for 24 hours with the mounted 5 .~heeting continuoll~ly rotated at 6 rpm to e -h~ -ce unirur~ y of deposition.Upon removal from the elecl-ofo"~ling bath, the cube-corner sheeting capable of e~ ;';n~ the glittering effect was removed from the electrodeposited metal to give a nickel mold, appro~ lely 0.025 inches (appro,.;.~a~ely 0.063 cm) thick, which was the negative image of the original glittering cube-corner 10 ~heeting The mold alone displayed the properties of glittering, although it did not exhibit the lahlbO~v hues of which the sheet;.-g was capable.
A mixture of 54.2 parts by weight of LSR-9151-200P liquid silicone rubber Par A and 5.4 parts by weight of LSR-9195 1-200P Part B (both parts A
and B available from Dow Corning, Midland, Michigan) was stirred thoroughly 15 and then deg~sed by sul~ecting to vacuum at room telllpc;lal~lre for 15 mimlteS~ The resulting mixture was applied to the mold described above and allowed to fill all the cavities. The filled tool was heated at 370 ~F for 10 minutçs then allowed to cool to room telllpclalure. Removal of the cured ~he.,t;-~e from the mold gave an o~ nquç, white .~.1 ,e~ that was capable of fine 20 glittering from the back side of the ~he.,lil~g and was not ~ ,o~enective.

E~cam~le 2 An elccl.oro.-.lcd tool preparcd acco.ding to Example 1 was used. A
~.~lure of 32.7 g of SX 863 magenta pl~stisol screen plillli"g ink (Plasto-O-25 Meric, Sussex, Wisconsin) and 13.6 g of Di-isononylrhth~l~te (Exxon Chemical Con.pa~y, Houston, Texas) was thoroughly mixed, then poured into the mold. The filled mold was heated at 390 ~F for 15 min~tç.~ then cooled to room te...~ t-lre. Removal of the sheeting from the mold gave a dark mag~nt~ colored glittering cheeting that was not lel,ort;llective and glittered.

W O97/41462 PCT~US96113146 Examl)le 3 An ele~,l,o~.,.~ed tool pl~pared accG,d;ng to Fysrnple 1 was used. A
mixture of 36.7 g of SX 863 m~çnt~s. plq~ti~ol screen printing ink and 30.5 g ofM2112 heat sealing plastisol (both available from Plasto-O-Meric, Sussex, S Wiscon~in) was thoroughly mixed, then poured into the mold. The filled mold was heated on a hot plate set to low le~"pe~alule for 2 min~ltes, then heated at370 ~F for 10 min~tes, and then cooled to room te.l.peralu,e. Removal of the shPeting from the mold gave a light m~ents, colored glittering shçeting that was not rel-or~nective and glittered from both sides of the .~heeting The 10 glittering from light tran~mitted through the ~heetine was red in color and the glittering from the back side of the shec l ;i~e was white.

Example 4 An ele~;l.ofo.-l.ed tool p~ep~d accordi,lg to Example 1 was used. A
mixture of 32.7 g of SX 863 .nage.-l,s, plastisol screen prhlling ink, 12.1 g ofSX 863 Cyan colored screen printing plastisol, and 41.6 g of M2112 heat sealing plastisol (all three available from Plasto-O-Meric, Sussex, Wisconslll) was thoroughly mixed, then poured into the mold. The filled mold was heated on a hot plate set to low te--lp~-al~lre for 2 min--tes7 then heated at 370 ~F for 10 minutec~ and then cooled to room tempe.alLlre. Removal of the ~hçetine from the mold gave a green colored glittering sheetine that was not orenective and exhibited the glittering effect from both sides of the chçetir~ The glittering from light tr~ led through the ~l~ee~ g was green in color and the glittering from the back side of the ~l.e~l;.-g was white.
All of the patents and patent applicstiQnc cited above are wholly incol~olated by rel'el~,nce into this patent app'ic~tion.
As illustrated by the above tiicc~lC~ion, the invention may take on various motlificqtions and alterations without depa, ~ g from its total scope and spirit. Acco~d;ngly, the invention is not limited to the above-described but is to be controlled by the limitations set forth in the claims and any equivalents thereof.

., .. , , . . . , . . ,--.. .

Claims (14)

CLAIMS:

1. A non-retroreflective glittering sheeting that comprises an array of cube-corner elements that are arranged in the array to such an extend that the sheeting glitters when light is incident thereon.

2. The sheeting of claim 1, wherein the array of cube-corner elements is defined by three sets of intersecting grooves, wherein each groove set includes two or more generally parallel grooves, and at least one groove in at least one of the sets has faces of adjacent cube-corner elements arranged such that a dihedral angle .alpha. located between the adjacent faces varies along the groove(s) in the set.

3. The sheeting of claims 1-2, wherein at least one groove in each of the three sets of intersecting grooves has faces of adjacent cube-corner elements arranged such that the dihedral angle .alpha. located between the adjacent faces varies along the grooves in all three groove sets.

4. The sheeting of claims 1-3, wherein the cube-corner elements each include a base plane and the cube-corner elements are arranged such that the base planes do not all reside in the same general plane when the sheeting is laid flat.

5. The sheeting of claims 1-4, wherein the cube-corner elements are randomly-tilted across at least a portion of the array, and wherein the cube-corner elements are about 20 to 200 micrometers high and exhibit a variation in height between adjacent apexes of 1 to 40 micrometers on average.

6. The sheeting of claims 1-5, wherein the cube-corner elements have base edges that do not lie in the same common plane when the sheeting is laid flat.

7. The sheeting of claims 2-6, wherein angle .alpha. ranges from 35 to 115 degrees on average.

8. The sheeting of claims 1-7, which contains a glittering image on a non-glittering background, a glittering image on a glittering background, or a non-glittering image on a glittering background.

9 The sheeting of claim 1, wherein the glitter produces at least about 50 points of light per square centimeter.

10. The sheeting of claims 1-9, wherein the array of cube-corner elements project from a body portion, and wherein the cube-corner elements, the body portion, or both are opaque.

11. The sheeting of claims 1-10, wherein opacity is provided by fillers, opaque pigments, or flakes.

12. The sheeting of claims 1-11, wherein the array of cube-corner elements project from a body portion that has a front surface, and wherein the sheeting is rendered non-retroreflective by having the front surface juxtaposed against an opaque surface.

13. A decorative article that comprises the sheeting of claims 1-12

14. The decorative article of claim 13 being a ribbon, bow, shred, tinsel, wrapping, cards, ornaments, wall coverings, window decorations, or fabric.