CA2107783C

CA2107783C - Launderable retroreflective applique

Info

Publication number: CA2107783C
Application number: CA002107783A
Authority: CA
Inventors: Wu-Shyong Li
Original assignee: Minnesota Mining and Manufacturing Co
Current assignee: 3M Co
Priority date: 1991-05-08
Filing date: 1992-03-09
Publication date: 2002-05-14
Anticipated expiration: 2012-03-09
Also published as: CA2107783A1; DE69219465D1; ES2101095T3; US5283101A; JP3048062B2; EP0583267A1; WO1992019993A1; EP0583267B1; DE69219465T2; JPH06507253A

Abstract

Retroreflective appliques comprising a monolayer of retroreflective elements partially embedded in and protruding from the front surface of a binder layer and an optional layer of adhesive on the rear surface of the binder layer, wherein the binder layer comprises an electron-beam cured elastomer.

Description

~AUNDERABLE RETROREFLECTIVE APPLIOUE
Field of Invention The present invention relates to novel retroreflective appliques and articles to which such appliques have been applied.
Background In order to improve safety of pedestrians, joggers, workers on roadways, etc., retroreflective markings have been attached to clothing. In one common embodiment, retroreflective appliques comprising a monolayer of retroreflective elements, e.g., transparent. microspheres with hemispheric reflectors, partially E=mbedded in a layer of binder material, with adhesive backings are bonded to articles of clothing.
Typically, the binder materials in such appliques comprise thermally or chemically cured compositions, e.g., phenolic cured resins, isocyanate cured polymers with active hydrogens such as two part urethanes, and aminoplast- or amine-cured hydroxy functional polymers. A problem with such appliques is that their retroreflective performance tends to diminish u=nacceptably when the garment to which they are bonded is washed. After a few washings, the retroreflective brightness of the applique may be reduced to a small fraction, e.g., 5 percent or less, of its original brightness. This decrease is due to loss of retroreflective elements from the surface of the applique and/or degradation of the retroreflective elements, e.g., corrosion of aluminum hemispheric reflectors, during washing.
Th.e problem is particularly troublesome when the clothing is subjected to industrial laundering, where the conditions of laundering are often more severe than conventional home laundering. For instance, in an industrial laundry, the laundering condition:. may include wash temperatures of 40° to 90°C
(105° to 7.90°F) and pH of 10 to 12.5, whereas in ~1~7783 contrast, typical conditions for home laundering may include temperatures of 4° to 60°C (40° to 140°F) and pH of less than 11. Also, home laundering equipment typically subjects the articles being cleaned to less rigorous handling and stress than does industrial laundry equipment.
Summary of Invention The present invention provides novel retroreflective appliques which can be applied to substrates such as fabrics and garments to impart retroreflective properties thereto. The appliques of the invention provide unexpected durability. Capable of being applied to fabric substrates, appliques of the invention exhibit surprising resistance to degradation when the article is laundered and retain a surprising degree of retroreflective properties.
In brief summary, retroreflective appliques of the invention comprise a monolayer of retroreflective elements partially embedded in and protruding from the front surface of a binder layer and an optional layer of adhesive, preferably hot melt type, on the rear surface of the binder layer. The adhesive layer is optionally covered with a removable release liner. In some embodiments, the applique is bonded to a substrate, e.g., a piece of fabric or article of clothing, with the adhesive, and in other embodiments the binder layer serves to both secure the retroreflective elements and to bond the applique to a desired substrate. If desired, the applique can be sewn onto a fabric substrate. In an important distinction from previously known retroreflective appliques, the binder layer of appliques of the invention comprises an elastomeric composition crosslinked or cured by electron beam ("e-beam") radiation.
Retroreflective appliques of the invention have been found to exhibit surprising retention of retroreflective brightness when subjected to industrial laundering conditions. This advantageous result is achieved through a combination of increased resistance to loss of retroreflective elements and an increased resistance to degradation of the retroreflective elements, e.g., degradation of the reflector layer. As a result, articles to which appliques of the invention have been applied may be laundered many more times than previously possible while still retaining the desired retroreflective character.
According to one aspect of the present invention, there is provided a retroreflective app:Lique wherein said applique comprises a monolayer of retro:reflective elements partially embedded in and protruding from the front surface of a binder layer wherein said binder layer comprises at least one of the following electron-beam cured el<~stomers:
chlorosulfonated polyethylene, ethylene copolymers, and EPDM
polymers, said applique being applied to a garment.
According to another aspect o:E the present invention, there is provided a retroreflective applique wherein said applique comprises a monolayer of retro:reflective elements partially embedded in and protruding from the front surface of a binder layer wherein said binder layer comprises at least one of the following electron-beam cured elastomers:
chlorosulfonated polyethylene, ethylene copolymers, and EPDM
polymers, said applique being sewn to a fabric.
Brief Description of Drawing The invention will be further explained with reference to the drawing, wherein:
Figure 1 is cross-sectional i:Llustration of a portion of an illustrative embodiment of a retroreflective applique of the invention; and 3a Figure 2 is cross-sectional i:Llustration of a portion of another illustrative embodiment of a retroreflective applique of the invention bonded to a substrate.
These figures, which are idea:Lized, are not to scale and are intended to be merely illustrative and non-limiting.
Detailed Description of Illustrative Embodiments Reference is made to Figure 1 wherein is shown an illustrative embodiment of retroreflect:ive applique 10 of the invention. Applique 10 comprises a monolayer of l0 retroreflective elements 12 partially embedded in and protruding from front surface 14 of binder layer 16. Disposed on rear surface 18 of binder layer 16 i;s optional adhesive layer 20. Applique 10 is shown with opi:,ional release liner 22 which covers the exposed surface of adhesive layer 20. To apply applique 10 to a substrate such a;s a fabric (not shown), release liner 22 is first removed. App:Lique 10 is also shown on optional temporary carrier 8 comprising paper sheet 4 and polymer lining 6.

WO 92/19993 ' ' PGT/US92/01944 In brief summary, a typical method of making appliques of the invention comprises arranging retroreflective elements in desired monolayer arrangement on a temporary carrier with the rear portions of the retroreflective elements presented away from the carrier, forming a binder layer over the rear portions of the retroreflective elements, and applying an optional adhesive layer on the back side of the binder layer.
The most typical form of retroreflective elements 12 will be spherical microspheres 24 having reflectors 26 on the back sides thereof as shown in Figure 1. As known to those skilled in the art, one method for assembling a monolayer of such retroreflective elements is to cascade microspheres onto temporary carrier 8 which secures microspheres 24 in desired arrangement temporarily. For instance, microspheres 24 can be partially embedded in heat softenable polymer layer 6 on paper sheet 4. Some examples of useful polymer coatings include polyvinyl chloride, polysulfones, polyalkylenes such as polyethylene, polypropylene, and polybutylene, polyesters such as polyethylene terephthalate, and the like. Upon cooling, polymer layer 6 retains microspheres 24 in desired arrangement. Depending in part upon the characteristics of carrier 8 and elements 12, it may be desired to condition carrier 8 and/or elements 12 to achieve desired release properties. For instance, selected release agents or adhesion promoters may be used.
Microspheres 24 are typically preferably packed as closely as possible, ideally in their closest hexagonal arrangement, to achieve greater retroreflective brightness and may be so arranged by any convenient applique process, such as printing, screening, cascading, or with a hot can roll.
The most typical kind of retroreflective elements are transparent microspheres having reflectors on the rear surfaces thereof as shown in Figure 1.

W0 92/19993 2 ~ ~ ~ ~ ~ 3 Such retroreflective elements typically provide satisfactory levels of retroreflective brightness over a wide range of incidence angles, i.e., the angles at which the light strikes the sheeting, a property 5 sometimes referred to as "angularity".
If 'transparent microspheres are used, the microsphere;s are preferably substantially spherical in shape in order to provide the most uniform and efficient retroreflection. Furthermore, the microspherea are preferably substantially transparent so as to minimize the amount of light absorbed by the microsphere:~ and thereby optimize the amount of light which is reltroreflected by sheetings of the invention.
The microspheres are typically substantially colorless, but, may be colored to produce special effects if desired.
Mic~~ospheres used herein may be made from glass or synthetic: resin having the optical properties and physical ch<iracteristics taught herein. Glass microsphereaa are typically preferred because they typically cost less, are harder, and exhibit superior durability i~o microspheres made of synthetic resins.
Microspheres used in the present invention will typically h<ive an average diameter of between about 30 and about 200 microns. Microspheres which are smaller than this r<~nge may tend to provide lower levels of retrorefleci~ion because of diffraction effects, whereas microspheres larger than this range may tend to impart undesirably rough texture to the applique or undesirably reduce the flexibility thereof.
Microsphere:a used in the present invention will typically hive a refractive index of between about 1.7 and about 2..0, the range typically considered to be useful in m:Lcrosphere-based retroreflective products where, as hE~re, the front surfaces of the microspheres are exposed or air-incident.
As mentioned above, microsphere-based retroreflect:ive elements of retroreflective appliques of the invention have reflectors on the rear surfaces 21~17'~~3 WO 92/19993 ~ ~ PCT/US92/01944 thereof. Typically, such reflectors are applied to the rear surfaces of the microspheres after the microspheres have been partially embedded in the carrier, thereby facilitating the arrangement of the microspheres in substantially uniform direction for retroreflection. Furthermore, as is known, the size of reflectors, i.e., how much of the surface of the microspheres which is covered, may be controlled in part by controlling the depth into the carrier to which the microspheres are embedded prior to application of the reflectors thereto.
Among the variety of materials which may be used as reflectors are vacuum-deposited or vapor-coated metal coatings, such as aluminum or silver;
chemically-deposited metal coatings, such as silver;
metal-coated plastic films; metal flakes; such as aluminum or silver; and dielectric coatings. Aluminum or silver coatings are typically preferred, because they tend to provide the highest retroreflective brightness. The reflective color of silver coatings is typically preferred to that of aluminum coatings, but an aluminum vapor coat is normally more preferred, because silver reflective coatings typically suffer more severe degradation in outdoor exposure than do aluminum coatings. U.S. Patent No. 3,700,305 (Bingham) discloses dielectric mirrors or coatings that may be used as reflectors in retroreflective articles of the invention.
An advantage of dielectric reflectors is that 3o appliques made with microspheres having such reflectors may be easily made in a variety of bright colors. Such reflectors are typically subject to degradation under laundering conditions, particularly industrial laundering conditions, and are accordingly used on articles destined for home laundering. Aluminum and silver reflectors typically exhibit substantially greater durability under industrial laundering conditions, but aluminum reflectors often tend to impart a gray color to the applique under ambient conditions.
Fol:lowing arrangement of reflective elements 12, a composition forming binder layer 16 is applied thereover. Binder layer 16 is typically between about 50 and about: 250 microns (2 and 10 mils) thick over the embedded portion of retroreflective elements 12, with thicknesses of between about 75 and about 100 microns (3 and 4 mi:Ls) typically being preferred. It will be l0 understood that binder layers having thicknesses outside there ranges may be used. However, if binder layer 16 is too thin, it will not provide sufficient support to retroreflective elements 12 which will may be readily dislodged, whereas increasing the thickness of binder layer 16 leads to increased cost for applique 10 as greatear amounts of the binder material are required. Furthermore, at greater thicknesses, greater e-beam dosages will be required to achieve suitable curing and t:he flexibility of applique 10 typically tends to decrease.
Binder layer 16 consists essentially of the binder materials, i.e., e-beam curable elastomers, discussed herein with the additives discussed below.
One useful example of such compositions is the HYPALONTM series of polymers, a series of chlorosulphonated polyesters from E.I. du Pont de Nemours & Co. ("du Pont"). Such materials are highly flexible, arid have been found to be resistant to degradation by exposure to ozone, oxygen, weathering, oil, and many chemicals as well as harsh laundering conditions.
Such binder materials offer improved performance as compared to that of binder materials used in previously known retroreflective appliques.
For instance:, phenolic-cured nitrile rubbers have been found to be sensitive to high temperature and high pH, resulting in discoloration and loss of retroreflective brightness. The presence of the phenolic functionalit:ies is believed to make such binder layers ~1O?7~3 WO 92/19993 ~ PCT/US92/01944 susceptible to undesirable degradation. Two component urethanes have been found to be sensitive to degradation upon exposure to high moisture as well as high temperature and high pH wash conditions. The urethane linkages are believed to make such binder layers susceptible to undesirable degradation. Such materials are also typically relatively expensive.
Moisture-cured one component urethanes suffer similar drawbacks and in addition are slow and difficult to cure controllably. If overcured, such binder layers tend to become insufficiently flexible and subject to loss of retroreflective elements when flexed.
The binder layer comprises one or more elastomers and typically one or more crosslinkers and one or more coupling agents. If desired, it may also comprise such optional additives as colorants (e. g., pigments, dyes, metal flakes) and stabilizers (e. g., thermal stabilizers and antioxidants such as hindered phenols and light stabilizers such as hindered amines or ultraviolet stabilizers), flame retardants, and flow modifiers (e. g., surfactants such as fluoropolymer silicones). Preferred colorants for appliques with reflective elements having aluminum reflector layers are black dyes, e.g., metal-azo dyes such as chromium-azo dyes.
Elastomers which may be used herein include those which are e-beam curable. Illustrative examples thereof include chlorosulfonated polyethylenes (e. g., du Pont's HYPALONTM series), styrene-butadiene(isoprene)-styrene block copolymers (e. g., Shell Chemical Company's KRATON~ series), nitrile rubbers (e. g., B.F. Goodrich's HYCARTM series), poly(butadiene-co-styrene), ethylene copolymers such as ethylene/vinylacetate, ethylene/acrylate, ethylene/
acrylic acid, and polyethylene-co-propylene-co-diene) ("EPDM") polymers.
Some elastomers tend to be degraded by e-beam irradiation rather than crosslinked. For instance, polyisobutylene, butyl rubber (e. g., isoprene/

~~ ~7'~~3 ~~ WO 92/19993 - PCT/US92/01944 isobutylene: copolymer), and neoprenes (e. g., polychloro~:rene) are typically not useful herein. The binder lays:r is preferably substantially free of these components.
Illustrative examples of crosslinkers which may be used herein include multifunctional monomers and oligomers such as trimethylolpropanetrimethacrylate, pentaerythritol-triacrylate, and triallyl-1,3,5-triazine- 2,4,6(1H,3H,5H)trione.
Illustrative examples of other useful crosslinkers include 1,6-hexanediol diacrylate, tetraethylene glycol diacrylate, neopentylglycol diacrylate, tripropylene glycol diac.rylate, trimethylolpropane ethoxy triacrylate., tris(2-hydroxethyl) isocyanurate triacrylate., dipentaerythritol pentaacrylate; urethane acrylate oligomers (e. g., CN970 series from Sartomer Co. and EBE~RCRYLTM from Radcure Specialties, Inc.), epoxy acrylate oligomers, and acrylic oligomers.
Crosslinkers may be used alone or in combination of one or more. Typically, the binder layer will contain up to about 10 weight percent, and preferably between about 0.5 and about 2 weight percent, of crosslinker. If too much crosslinker is used, the resultant binder layer may tend to be insufficiently flexible. Also, because many crosslinkers tend to be susceptible to degradation due to water and high pH, binder layers made with excessive amounts may tend to suffer impaired launderability. If too little crosslinker is used, the resultant binder layer may not be cured sufficiently and thus be subject to degradation, e.g., swelling and retroreflective element loss, under laundering conditions, or require high e-beam dosage to achieve sufficient cure.
Typically, it is preferred that the binder layer be sufficiently cured so as to withstand immersion at room temperature for 24 hours in methylene chloride without dissolving or breaking apart. Acceptable binder layers may swell in this test so long as they do not dissolve or break apart. It will be understood that use of 21~'~783 higher e-beam dosages to achieve sufficient curing will typically incur greater processing costs and perhaps slower manufacturing speeds. Also, higher e-beam dosages may lead to degradation of some components of 5 the construction.
Typically, binder layer 16 will comprise a coupling agent, e.g., silane coupling agent, to promote adhesion of binder layer 16 to retroreflective elements 12. Selection of a coupling agent will be based in 10 part upon the particular elastomer, crosslinker (if any), and retroreflective elements which are used.
Illustrative examples of coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, gamma-methacryloxypropyl-tris-(2-methoxyethoxy)silane, gamma-methacryloxypropyltrimethoxysilane, beta-(3,4-epoxycyclohexy)ethyltrimethoxysilane, gamma-glycidoxypropyltrimethoxysilane, gamma-mercaptopropyltriethoxysilane, gamma-mercaptopropyltrimethoxysilane, gamma-aminopropyltriethoxysilane, and N-beta-(aminoethyl)-gamma-aminopropyltrimethoxysilane.
These may be used singly or in combination. It will be understood that selection of coupling agent(s), if used, will be dependent in part upon the binder material and retroreflective elements used. To minimize fading of aluminum reflector layers, it is typically preferred that amino-containing silane coupling agents be avoided.
Gamma-glycidoxypropyltrimethoxysilane, gamma-mercaptopropyltrimethoxysilane, and gamma-methacryloxypropyltrimethoxysilane have been found to exhibit the best performance among those listed and are preferred.
The coupling agent may be applied, e.g., by spraying or coating, to the surfaces of the retroreflective elements or to the binder layer prior to its application to the elements or may be incorporated directly into the binder composition.
Application to the elements provides the advantage of 2a ~77R~

using lesser quantities of coupling agent, which in some instances is relatively expensive, whereas incorporation into the binder composition provides the advantage of eliminating a separate application process curing fabrication of the retroreflective applique.
Typically, binder layer 16 will contain up to about 10 weight percent, and preferably between about 0.1 and about 7 weight percent, of coupling agent. If too little coupling agent is used, the resultant l0 applique may, depending upon the characteristics of the elastomer, tend to under undesirable loss of retroreflective elements. If too much coupling agent is used, it may in some instances impair the physical properties of the binder layer, e.g., mercapto-based agents may cause the binder to swell. Also, the coupling agents are typically relatively expensive as compared to the other components of the appliques.
Examples The invention will be further explained by the following illustrative examples which are intended to be non-limiting. Unless otherwise indicated, all amounts are expressed in parts by weight.
Unless otherwise indicated, the following test methods were used.
Retroreflective Brightness Retroreflective brightness was measured using a retroluminometer as described in U.S. defensive publication T987,003 at divergence angles of about 0.2°
and entrances angles of about -4°.
Launder incr Launderability of appliques was evaluated by washing a piece of fabric to which the subject applique had been applied for the indicated number of cycles in a Milnor System 7 Washing Machine Model 30015M4G from Pellerin Minor Corp. using program no. 5 for medium soiled, colored fabric with the indicated detergent.

~~1~.~''~7~~
Each cycle as about 4o minutes in length. The washer was loaded ~~tith about 5.5 to 6.8 kilograms (12 to I5 p011ndBj (dr;~) of laundry and used about 68 liters (18 gallons) of water at the indicated tetmperature.
Ths detergent used was 30 grams of FACTOR''M
detergent, :~ detergent from gabrilife chemicals, Znc.
containing l:etrasodium pyrophoaphato, nonylphanox~~poly(sthyisneoxy)ethanol, sedium carbonate, and silica. In some cases, the detergent gurther included 60 grams of ULTRASIL~, a pH builder from Pennwalt Co~'p. believed to contain 4o Weight parcQnt NaOH and 60 weight percent sodium metasilicatas.
Examr~e 1 GlaE~s micrcapheres having an average diameter of about 40 to 90 r~i:,rona were partially embedded into a temporary carrier sheet and aluminum spacular reflective layers arplisd to the exposed portions of the microspherea to yield retrcreflactive elements.
A binder ca:~positicn comprising:
mount C o~go are t 100 E;lastolrar - 35 weight porcent solution of HYPALCN"'' 20 in methyl ethyl keZOne with about Q~C45 weight percent of ZAPONTM X50, black dye from BASF Carp.;
Z.l Coupling Agent - A~189, a gamma-mercapto-- prOpyltrimethoxysilane fxom Union Carhide Corp.; and 0.35 Crosslinker - trimethylolpropanstrimQth-Efcrylate having molecular weight of 338.4 from Aldrioh Chemical Co.;
coated over the retroretiective eihrtants to a wet thicknsas of about 30o microns (12 mils) and dried at about~66°C (150°F) for 30 minutes. The dried coating was then s-beam irradiated to an exposure of 3 or s Mrads at 200 kilovolts to yield the binder layer. An Mrad is a me~garad where. a red or ~~radiation absorbed doss" is equal to 1.0 x 10's joulea/gran~.
~t~~S! i i ~~~ S~i~~l ~ 2 Q2 93 ~~.Q'~'~83 An adhesive layer comprising (1) 100 parts of a 40 percent solids solution of a polyol having a hydroxy equivalent oi° 3000 in methyl ethyl ketone and (2) 6.5 parts of DESZ40DURTM CB-75, a 75 percent solids solution of an aromatic polyisocyanate adduct based on toluene diisocyanate in ethyl acetate from Mobay Corp., was then coated over the rear side of the binder layer to a wet thicknes:~ of about 300 microns (12 mils).
The resultant retroreflective applique was then wet laminated to a polyester fabric (S-551-060 from Milliken & Company, a 3.11 ounce/yard2 textile polyester) and the construction dried and cured at 65°C
(150°F) for 30 minutes. The temporary carrier was then stripped from the front of the applique to reveal the silver colored retroreflective surface.
Launderability of the appliques was evaluated by washing f ~r the indicated number of cycles at a water temperature of about 83°C (180°F). The appliques had initial retroreflective brightnesses in candelas per square meter per lux ("cps") of about 605, 570, 600, and 615, respectively. The launderability results obtained are tabulated in Table I.
Table I
Cures Cvcles2 Aaent3 Brig~htness4 3 0 F + U 100 3 5 F + U 82 3 10 F + U 53 3 15 F + U 35 3 20 F + U 25 3 25 F + U 20 5 0 F + U 100 5 5 F + U 79 5 10 F + U 46 5 15 F + U 29 5 20 F + U 19 5 25 F + U 15 3 2 0 F~ 5 8 1 E-beam exposure in Mrads.
2 Number of wash cycles completed.
3 Cleaning agents) used - F indicates FACTORTM and U indicates ULTRASILTM.
4 Percentage of its initial retroreflective brightness that indicated sample retained after indicated number of wash cycles.
These results illustrate the superior launderability of retroreflective appliques of the invention as compared to conventional appliques made with thermo-chemically cured binder layers.
Example 2 Two different crosslinkers are examined in Example 2. Except as noted below, retroreflective appliques were made as in Example 1. In Sample 2-1 the crosslinker was o.35 parts of trimethylolpropane-trimethacrylate, and in Sample 2-2 the crosslinker was 0.35 parts of pentaerythritoltriacrylate. In both cases, the binder composition was coated to a wet thickness of 250 microns (10 mils), oven dried at 65°C
(150°F) for 10 minutes, covered with a 25 micron (1 mil) thick silicone coated polyethylene terephthalate 21~~'~~3 film, and exposed to 5 Mrads at 200 kilovolts through the f i lm .
After the film was removed, an adhesive composition comprising (1) 100 parts of a 50 percent 5 solids solution of linear saturated polyester in methyl ethyl ketone and toluene and (2) 2.4 parts of DESMODUR~ CB-75 was applied. The applique was then wet laminated to a polyester fabric as in Example 1.
After the temporary carrier was removed from 10 the front of the appliques, the appliques were allowed to sit at room ambient conditions for 1 month. The launderability of the samples was then evaluated using by washing as in Example 1 for the indicated number of cycles using water having a temperature of about 75°C
15 (165°F). Th.e appliques had initial retroreflective brightnesses~ (in cpl) of about 615 and 620, respectively. The launderability results obtained are tabulated in Table II.
Table II
Sam ale Cycled Brightness2 2-1. 0 100 20 1.6 2-:'. 0 100 1 Number of wash cycles completed.
2 Percentage of its initial retroreflective brightness that indicated sample retained after indicated number of wash cycles.

Example 3 A monolayer of retroreflective elements was prepared as in l;xample 1.
A binder composition comprising a solution in toluene of (1) 26.7 weight percent of elastomer, KRATON~ D1320X, and (2) 1.6 weight percent of coupling agent, A-189 was coated over the retroreflective elements to a wet thickness of about 300 microns (12 mils) and dried at about 65°C (150°F) for 30 minutes.
The dried coating was then e-beam irradiated to exposures of 0, 3, or 5 Mrads at 200 kilovolts as indicated to yield the binder layer.
An adhesive layer comprising (1) 100 parts of a 40 percent solids solution in methyl ethyl ketone of polyol having an hydroxy equivalent of 3000 and (2) 8.6 parts of DESMODUR~ CB-75 was then coated over the rear side of the binder layer to 150 microns (6 mils) wet thickness.
The resultant retroreflective applique was then wet laminated to a PRIMALUX~ fabric (an 80/20 blend of polyester and combed cotton, weight 3 ounce/yard2) from Springs Industries, Inc. The construction was dried and cured at 65°C (150°F) for 30 minutes. The temporary carrier was then stripped from the front of the applique to reveal the silver colored retroreflective surface.
Launderability of the applique was evaluated by washing for the indicated number of cycles at a water temperature of about 74°C (165°F). The appliques had initial retroreflective brightnesses (in cpl) of about 660, 645, and 650, respectively. The launderability results obtained are tabulated in Table III.
Table III
Cure1 Cycles2 Brightness3 21t~~7R3 E-lbeam exposure in Mrads.
Number of wash cycles completed.
l0 3 Percentage of its initial retroreflective brightness that indicated sample retained after indicated number of wash cycles.
Example 4 A monolayer of retroreflective elements was prepared as in Example 1.
A binder composition comprising:
Amount Component 100 Elastomer - solution in methyl ethyl ketone of 35 weight percent percent HYPALONTM 20 and 0.045 weight percent ZAPONTM X50;
2.1 Coupling Agent - A-189;
0.35 Crosslinker - trimethylolpropanetrimeth-acrylate;
was coated over the retroreflective elements to a wet thickness of about 375 microns (15 mils). Appliques were then we.t laminated to PRIMALUX~ fabric like that used in Example 3, referred to as Sample 4-1, or S-551-060 fabric like that used in Example 1, referred to as Sample: 4-2 and dried at about 65°C (150°F) for 30 minutes. Th.e dried composites were then e-beam irradiated t.o an exposure of 7 or 10 Mrads at 300 kilovolts through the fabrics to yield the binder layers bonded to the respective fabric substrate.
The temporary carriers were then stripped from the front of the appliques to reveal the retroreflect.ive surfaces which each provided a brightness of about 600 candela per square meter per lux.

210'783 Launderability of the appliques was evaluated by washing for five cycles with water at a temperature of about 82°C (180°F).
Sample 4-1 had an initial retroreflective brightness of about 625 candela per square meter per lux and a final retroreflective brightness of about 270 candela per square meter per lux. Sample 4-2 had an initial retroreflective brightness of about 620 candela per square meter per lux and a final retroreflective brightness of about 300 candela per square meter per lux.
Sample 4-2 was observed to have retained a somewhat greater degree of its retroreflective brightness than did Sample 4-1. This is believed to be due to the fact that S-551-060 fabric is somewhat stiffer than is PRIMALUX~ f abr i c .
Comparative Example A
An array of retroreflective elements on a temporary carrier was prepared as in Example 1.
A binder composition comprising:
Amount Component 100 Binder Material - 45 weight percent solids emulsion in water of non-ionic acrylic emulsion, RHOPLEX~ HA-8 from Rohm & Haas;
2 Binder Material - 80 weight percent aqueous solution of melamine-formaldehyde resin;
and 2 Coupling Agent - Z-6040 from Dow Corning Corp.;
was coated over the retroreflective elements to a wet thickness of about 150 microns (6 mils) and dried and cured at 82°C (180°F) for 7 minutes to yield the binder layer.
A layer of the same composition except further containing 0.2 parts carbon black and 3.0 parts titanium dioxide was coated over the back side of the binder layer to a wet thickness of about 175 microns (7 mils).

2~p~~~3 The <ipplique was then wet laminated to a polyester/coi~ton blend, POTENTIATM, a 3.0 ounce/yard2 65/35 blend of polyester and combed cotton from Springs Industries, :Cnc. and the laminate dried and cured at 110°C (230°F) for 7 minutes.
The i~emporary carrier was then stripped from the front of the applique to reveal the silver colored retroreflect:ive surface. The initial retroreflective brightness was about 605 candela per square meter per lux.
Comparative l~xample B
An a~__~ray of retroref lective elements on a temporary ca~~rier was prepared as in Example 1.
A binder composition comprising:
Amount Component 100 Binder Material - 20.5 weight percent solids solution in methyl ethyl ketone of nitrile rubber;
13.7 Binder Material - thermosetting phenolic resin;
4.1 Binder Material - dioctyl phthalate plasticizer;
2 Coupling Agent - A-189; and 2 Colorant - dispersion of carbon black and titanium dioxide;
was coated over the retroreflective elements to a wet thickness of about 150 microns (6 mils) and dried and cured at 77°C: (170°F) for 3 minutes and then 154°C
(310°F) for ~E minutes to yield the binder layer.
An adhesive composition comprising: (1) 100 parts of BOS'rIKTM 7660, a 30 weight percent solids solution in ;methyl ethyl ketone of a polyester diol from Emhart ~Corp. and (2) 4 parts of BOSCODURTM No. 22, a 66 weight ;percent solids solution in ethyl acetate and toluene (1:1) of a polyisocyanate from Emhart Corp., was dated over the back side of the binder layer to a wet thickness of 175 microns (7 mils).

2107'83 The applique was then wet laminated to a fabric as in Example 1 and the temporary carrier stripped from the front of the applique to reveal the silver colored retroreflective surface. The initial retroreflective 5 brightness was about 560 candela per square meter per lux.
Comparative Example C
In this Comparative Example, a piece of 10 REFLITE~ Retroreflective Fabric from Nippon Reflite Industry Company of Uji-City, Japan was evaluated. The material comprises a monolayer of aluminum-coated microspheres partially embedded in a binder layer which is believed to comprise a urethane binder material.
15 The fabric had an initial retroreflective brightness of about 630 candela per square meter per lux. The launderability results obtained with the appliques of Example 1 and Comparative Examples A, B, and C are tabulated in Table IV.
20 As reported above, the initial retroreflective brightness of Sample 1 was about 605 candela per square meter per lux.
Table IV
Cyclesl Agent2 Brightness3 ~- A_ B_ C_ 5 F + U 82 -- 67 <2 10 F + U 53 -- 21 -15 F + U 34 -- 4 -20 F + U 25 -- <1 -21~"~7R3 ' Numbgr of wash cycles complsted at water temperature of 83°C (16o°P') except Comparative Example C which was at 66°C (150°F).
Cleaning Agents) used - F indicates FACTOR'"' and U
indicates 1JLTRASILrM, ' percentage of its initial retroreflactiva brightness that indicated sample ratainsd after indicated number of wash cyclaa.
The*e; results illustrate the ouporior lp launderabilit:y of ratrorGtlective appliguse of the invention ag compared to conventional appliguea msde with tharmo-c:hemically cured binder layers.
Vatic>ua modifications and alterations oP this invention wi7.l Decome apparent to those r~killod in the 15 art without departing >:xom the *cope of this invention.
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Claims

CLAIMS:

1. A retroreflective applique wherein said applique comprises a monolayer of retroreflective elements partially embedded in and protruding from the front surface of a binder layer wherein said binder layer comprises at least one of the following electron-beam cured elastomers:
chlorosulfonated polyethylene,, ethylene copolymers, and EPDM polymers, said applique being applied to a garment.

2. The applique of claim 1, wherein said binder layer further comprises at least one of the following:
a crosslinker, a coupling agent, a colorant, a stabilizer, a flame retardant, and a flow modifier.

3. The applique of claim 2, wherein said crosslinker comprises one or more multifunctional monomer or oligomer.

4. The applique of claim 2, wherein said crosslinker is selected from one or more of the following:
trimethylolpropanetrimethacrylate, pentaerythritol-triacrylate, triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)trione, 1,6-hexanediol diacrylate, tetraethylene glycol diacrylate, neopentylglycol diacrylate, tripropylene, glycol diacrylate, trimethylolpropane ethoxy triacrylate, tris(2-hydroxethyl) isocyanurate triacrylate, dipentaerythritol pentaacrylate, urethane acrylate oligomer, epoxy acrylate oligomer, and acrylic oligomer.

5. The applique of any one of claims 2 to 4, wherein said coupling agent is selected from one or more of the following:
vinyltrimethoxysilane, vinyltriethoxysilane, gamma-methacryloxypropyl-tris-(2-methoxyethoxy)silane, gamma-methacryloxypropyltrimethoxysilane, beta-(3,4-epoxycyclohexy)-ethyltrimethoxysilane, gamma-glycidoxypropyltrimethoxysilane, gamma-mercaptopropyltriethoxysilane, gamma-mercaptopropyltri-methoxysilane, gamma-aminopropyltriethoxysilane, and N-beta-(aminoethyl)-gamma-aminopropyltrimethoxysilane.

6. The applique of any one of claims 1 to 5, further comprising a layer of adhesive on the rear surface of said binder layer.

7. The applique of claim 6, wherein said adhesive is a hot melt adhesive.

8. The applique of claim 6 or 7, wherein said applique is bonded to the garment with said adhesive.

9. The applique of any one of claims 1 to 8, wherein said retroreflective elements comprise microspheres with hemispheric reflectors thereon.

10. The applique of claim 9, wherein said reflectors comprise vapor-coated aluminum.

11. The applique of claim 9, wherein said reflectors comprise dielectric vapor coats.

12. A retroreflective applique wherein said applique comprises a monolayer of retroreflective; elements partially embedded in and protruding from the front surface of a binder layer wherein said binder layer comprises at least one of the following electron-beam cured elastomers:
chlorosulfonated polyethylene, ethylene copolymers, and EPDM polymers, said applique being sewn to a fabric.

13. The applique of claim 12, wherein said binder layer further comprises at least one of the following:

a crosslinker, a coupling agent, a colorant, a stabilizer, a flame retardant, and a flow modifier.

14. The applique of claim 13, wherein said crosslinker comprises one or more multifunctional monomer or oligomer.

15. The applique of claim 13, wherein said crosslinker is selected from one or more of the following:
trimethylolpropanetrimethacrylate, pentaerythritol-triacrylate, triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)trione, 1,6-hexanediol diacrylate, tetraethylene glycol diacrylate, neopentylglycol diacrylate, tripropylene glycol diacrylate, trimethylolpropane ethoxy triacrylate, tris(2-hydroxethyl) isocyanurate triacrylate, dipentaerythritol pentaacrylate, urethane acrylate oligomer, epoxy acrylate oligomer, and acrylic oligomer.

16. The applique of any one of claims 13 to 15, wherein said coupling agent is selected from one or more of the following:

vinyltrimethoxysilane, vinyltriethoxysilane, gamma-methacryloxypropyl-tris-(2-methoxyethoxy)silane, gamma-methacryloxypropyltrimethoxysilane, beta-(3,4-epoxycyclohexy)-ethyltrimethoxysilane, gamma-glycidoxypropyltrimethoxysilane, gamma-mercaptopropyltriethoxysilane, gamma-mercaptopropyltri-methoxysilane, gamma-aminopropyltriethoxysilane, and N-beta-(aminoethyl)-gamma-aminopropyltrimethoxysilane.

17. The applique of any one of claims 12 to 16, wherein said retroreflective elements comprise microspheres with hemispheric reflectors thereon.

18. The applique of claim 17, wherein said reflectors comprise vapor-coated aluminum.

19. The applique of claim 17, wherein said reflectors comprise dielectric vapor coats.