AU593625B2

AU593625B2 - Clear coat definition control

Info

Publication number: AU593625B2
Application number: AU70557/87A
Authority: AU
Inventors: John William Frank; Jeffrey Robert Janssen; Brian Leroy Koster; Kenneth Gary Olson
Original assignee: Minnesota Mining and Manufacturing Co
Current assignee: 3M Co
Priority date: 1986-04-01
Filing date: 1987-03-24
Publication date: 1990-02-15
Anticipated expiration: 2007-03-24
Also published as: AU7055787A; JPH0638943B2; BR8701469A; DE3767947D1; MY100500A; JPS62289272A; AR244600A1; KR940011822B1; EP0257729B1; MX171635B; KR870009853A; ES2021035B3; EP0257729A1

Description

r 4 .593625 SPRUSON FERGUSON FORM 10 COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE: Class Int. Class Complete Specification Lodged: Accepted: "Mel~wts nde uAsI4 seuw49, 9.

00 *0* 9* t *0f I t~ Published: Priority: Related Art: and is 0 tatr ptwugi Name of Applicant: Address of Applicant: Actual Inventor(s): Address for Service: MINNESOTA MINING AND MANUFACTURING COMPANY 3M Center, St. Paul, Minnesota, United States of America JOHN WILLIAM FRANK, BRIAN LEROY KOSTER, JEFFREY ROBERT JANSSEN and KNNETH GARY OLSON Spruson Ferguson, Patent Attorneys, Level 33 St Martins Tower, 31 Market Street, Sydney, New South Wales, 2000, Australia t t 4 Complete Specification for the invention entitled: "CLEAR COAT DEFINITION CONTROL" including the best method of performing it known to us SBR/JS/0207M ~:z 41027 AUS 7A CLEAR COAT DEFINITION CONTROL Field of Tnvent ion This invention relates to a thin film graphic design article, and 'to methods for making same. more particularly, it relates to an article comprising a thin film graphic design having a protective coating thereover, with the protective coating having tapered edges, providing an appearance which is similar to that of paint.

Background on site application of paint directly to a surface to be decorated is the time-honored method for providing a graphic design, such as a decorative design. While such a process provides many aest-hetic and physical features, including realistic appearance, color flexibility, durability to abrasion, weathering and chemical attack, it also suffers from many disadvantages. For example, relatively skilled labor is necessary. Long application times are usually the rule, and potential contamination to adjacent areas, particularly mechanical equipment, can occur. Accordingly, prefabricated film graphics have been utilized Lo avoid It 25 many of these disadvantages. Such film graphics, often called "decals" or "transfer graphics", when utilized on the exterior surface of vehicles, typically require extreme resistance to abrasion and chemical attack because of exposure of the vehicle surfaces to various 30 atmospheres or environments. Accordingly, such graphics must generally be provided with a protective clear coat over the graphic Fareas.

This protective clear coat can be located in registry with the graphic area by applying a continuous layer of clear coat over the graphic and non-graphic areas, and subsequently cutting th7i. ough the several layr peisely at the outline of the graphic area, j r -2typically called "die cutting" or "kiss cutting". This approach results in substantially vertical or right angle edges of the graphic and protective clear coat which can collect dirt, wax, and other foreign materials which can detract from the aesthetics of Lhe applied graphic design. Responsive thereto, a sealing agent, such as SCOTCHCAL Brand 4150 Edge Sealer, available from the Minnesota Mining and Manufacturinj Company may be applied about the edges of such a graphic after application, to the side of a vehicle with adhesive. The sealing agent protects the exposed sides of the qraphic and adhesive from chemical attack and reduces the mechanical forces acting thereon. This technique is most typically practiced in the airline 15 industry.

A second approach is to apply the protective clear coat only to graphic areas, as, for example, by screen printing, or utilizing a stencil with an open area corresponding precisely to the outline of the graphic design. Those skilled in the art are aware of the difficulty encountered with such a process, because of 'factors such as dimensional changes in the film substrate, tension variables in the screen itesh, and accurate positioning of the substrate in registry with the stencil. Small graphics, such as those with overall dimensions of not greater than about 30 centimeters x 30 centimeters (12 inches x 12 inches) can generally be manufactured with satisfactory registration by those having requisite skill. However, this becomes much more difficult for larger graphic areas, and particularly for decorative items such as pin stripes which are common for the vehicle or automotive market.

U.S. Patent No. 4,356,617 (Coscia) discloses the formation of a raised dike around a graphic designL for the purpose of controlling the flow of a coating composition applied thereto. The reference further teaches that such flow may also be controlled by a -3groove or gap around the design if the coaling composition has sufficient surface tension. Patents Nos. 4,332,074 (Auld et al.) and 4,605,575 (Auld eL al.) disclose utilization of integral bezels for similar purpose.

Such techniques are typically not preferred because they may not provide the tapered edge which is desired of thin film graphic to impart a paint-like appearance thereto. Furthermore, the techniques disclosed in these references do not provide application of the protective clear coat to the adhesive layer which adheres the graphic design to a desired substrate, thereby leaving the edges of the adhesive exposed and subject to collection of foreign materials and environmental degradation.

Yet another approach which could be utilized is to apply the protective clear coat with a substantial oversize border to assure complete coverage of the graphic area. While this method achieves the required objective of protection for the graphic design, it I is generally considered not to be aesthetic.

Although application of a protective clear coat by screen printing is a typical technique, other methods such as roller coating or spray coating may also be considered, providing a dry film thickness of from about 0.01 to 0.1 millimeters (0.5 to about 4 mils) is achieved.

Summarizing, an acceptable protective clear coat should: be of sufficient thickness to provide adequate wearability and resistance to chemical environments; precisely cover the graphic area, whether same be large or small, and whether it be a simple geometric shape, such as a narrow width line, or a complex intricate design; and provide a tapered profile to the graphic. If desired the protective clear coat should also seal the underlying adhesive which adheres the graphic to a depired substrate. Known techniques described above do !ot satisfy all these requirements.

1 S -4- Accordingly, the present invention provides precise registration of a clear protective coat over a graphic pattern; the protective coat has tapered, rounded and sloping edges which inhibit the buildup of wax and foreign matter at the edge portions, and looks integrated with the substrate; provides a paint-like look; the process can accommodate varying process tolerances, operator variability and equipment tolerances; and the process provides a lenticular appearance on thin pin stripes, such as may be placed on vehicle surfaces. If desired, the protective coating may also cover the underlying adhesive'that is used to adhere the graphic to a desired substrate, thereby sealing the edges of the adhesive to further enhance the inhibition of the 'buildup of wax and foreign matter at the edges of the graphic, and providing unexpected A: .0 solvent resistance thereto.

Summary of Invention 20 In accordance with the invention, there is a process provided for preparing a graphic pattern having a protective coating thereon in "precise r registration" (as defined herein) therewith. The process r comprises: 1) providing a carrier having a major surface, 2) applying, in imagewise fashion, an imaging composition on the major surface of the carrier, which composition has sufficient surface tension to wet the major surface, to provide a film of the graphic pattern thereon, 3) drying the film of graphic pattern, 4) applying a liquid protective coating over the graphic pattern, beyond the edge definition thereof and in substantial registration therewith, the protective coating composition having a surface tension sufficient to wet the graphic pattern but not the major surface of the carrier film and 5) At drying the coating of protective material, whereby upon drying the protective overcoat dewets or retracts C r C\ Yi 77 b v 'N 1 from the major surface of the carrier totally onto the graphic pattern, thus providing precise registration therewith. If desired, multicolor graphic patterns may be provided by applying, in the appropriate imagewise fashion, one or more additional layers of imaging compositions of appropriate color.

In a preferred embodiment of the invention, a dry transfer graphic article comprising a graphic pattern and underlying adhesive is provided which has a protective coating thereon in "precise registration" (as defined herein) therewith such that the graphic has rounded and sealed edges and a paint-like appearance when applied to a desired substrate. The protective clear coat covers the graphic pattern and seals the 15 edges of the graphic pattern and also the underlying adhesive so as to protect the transfer graphic from abrasive forces and prevent collection of foreign matter at the edges of the graphic pattern and underlying adhesive. Further, the clear coat provides unexpected S 20 solvent resistance to the adhesive, thereby improving the durability and longevity of such graphics. The present invention also provides a process for making S'such a graphic transfer article.

Briefly summarizing, the process for making such a transfer graphic article comprises: 1) providing S' a carrier having a major surface; 2) coating a layer of adhesive, typically pressure-sensitive adhesive, thereon; 3) applying an imaging layer or stratum, e.g., tI t fe a polymer film of des;fred color or layer of an imaging composition such as an ink, thereover; 4) trimming H the imaging stratum and underlying adhesive in imagewise fashion to provide the desired graphic pattern, e.g., by kiss-cutting in imagewise fashion and then removing the nonimagewisq portions of the same; 5) applying a liquid protective coating over the graphic pattern, 11, I~ r X

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4r, t I f t4 to 44 04- 0,0 -6beyond the edge definition thereof and in substantial registration therewith, the protective coating composition having a surface tension sufficient La wet the graphic pattern and exposed edges of the underlying adhesive, but not the major surface of the carrier; and 6) drying the coating of protective material, whereby upon drying the protective clear coat dewets or retracts from the major surface of the carrier into precise registration with the graphic pattern, sealing the edges of the graphic pattern and underlying adhesive and providing a rounded profile. If desired, one or more layers of an imaging composition, ink, may be applied to -the imaging stratum to provide special effects, e.g., a multicolor graphic, etc., as discussed above.

Brief Description of Drawing The present invention is further explained with reference to the drawing which illustrates a preferred embodiment thereof wherein: 20 Figure 1 is a cross-sectional representation of an imaging stratum and underlying adhesive layer which have been applied -to a carrier; Figure 2 is a cross-sectional representation of the construction of Figure 1 after an image composition has been printed thereon and a desired graphic pattern has been formed by kiss-cutting and weeding in an imagewise fashion; Figure 3 is a cross-sectional representation of the construction of Figu~re 2 after a liquid protective coating has been applied and dried thereon; Figure 4 is a cross-sectional representation of the construction o Figure 3 after lamination of an application tape thereto; and Figure 5 is a cross-sectional representation of a preferr9d transfer graphic of the invention being applied to a substrate.

V

r ~1' These figures, which are not Lo scale, are intended to be merely illustrative and not limiting.

Detailed Description of Preferred Embodiment: of Invention The invention relates to a process for the mnniufacture of a dry transfer graphic material, comprising the steps of applying an image layer, typically comprising one or more layers of ink to a substrate surface to form a graphic pattern thereon, and applying thereover, a protective clear coat, the clear coat being applied, beyond the edge definition of the graphic pattern in substantial registration therewith, the surface energy of the substrate being sufficiently low relative to the surface tension of the protective clear coating that non-wetting by the protective coating occurs, and same therefor "creeps" back to the edge surface of the graphic pattern. The protective coating is thus in precise registration with -the graphic pattern thereby providing an aesthetically pleasing unitary or paint-like 20 appearance.

"1Precise registration" is defined herein to mean a slight oversize border which is approximately 0.12 millimeters mils) or less in width. Such borders provide the desired protection and sealing of the graphic pattern and, in some embodiments, the underlying adhesive; but are essentially undistinguishable to the unaided eye, thus clear coats having such borders appear to be in precise registration with the graphic or visually coincident therewitLh, In a preferred embodiment, the invention also relates to a transfer graphic article having a protective coating thereon such that the article, including graphic pattern and underlying adhesive in registry therewith, has rounded and sealed edges. The process for the manufacture of such a dry transfer graphic article comprises the steps of applying to a carrier *0 P 4#4

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surface an imaging layer or stratum, one or more layers of an imagingj composition, and underlying adhesive to form a desired graphic pattern; and applying thereover a protective clear coat, the clear coat being applied beyond the edge definition of the image areas in substantial registration therewith, the surface energy of the carrier being sufficiently low relative to the surface tension of the protective clear coating that non-wetting of the carrier by the protective coating occurs, and same therefor "creeps" back to the surface and edges of the graphic pattern and. underlying adhesive into precise registration ther~ewith.

The carrier comprises a material which inherently has a low surface energy, or has a low surface energy coating -thereon, a paper or polyester film with silicone coating thereon. The carrier functions to provide a base surface having sufficient rigidity on which to coat the adhesive and apply the imaging stratum, a polymez film, and trim the same in imagewise 20 fashion, by kiss cutting and removing weed; yet has a sufficiently low comparative surface energy such that as the clear liquid protective top coat dries thereon, same will nrt wet, or will retract from, the carrier surface onto the graphic film and and underlying adhesive. In addition, the carrier functions as a release liner and must allow for easy release of the graphic transfer therefrom, the adhesion of the adhesive therato should bereleasable.

The imaging stratum comprises a material such as a polymer film or ink. The film is preferably a material of desire4 color Which has a surface energy which is higher than that of the carrier such that when the protective clear coat is applied it will dewet or retract from the carr~ier surface onto the imaging stratum and underlying adhesive.

The underlying adhesive should provide high I I

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t t1~ I I 1~ 1* i I-i j -9adhesion to the imaging stratum and desired substrate to which the ultimate graphic is applied, yet should releasably adhere to the carrier.

The adhesive may first be coated on the carrier and the imaging stratum then applied thereto, or it may first be coated on the imaging stratum, a film, following which the precoated imaging stratum is applied to the carrier. The adhesive should form a substantially continuous layer covering at least the area of the desired graphic pattern, and preferably extends at least slightly therebeyond, such that a layer of adhesive will underly substantially all of the graphic pattern, providing secure adhesion to the substrate. Examples of suitable adhesive-precoated films include SCOTCHCAL Brand 3650 Series Polyvinyl Chloride Films, and SCOTCHCAL Brand 5690 Series Polyester Films, which have acrylic type pressure-sensitive adhesives on the back side and are available from the Minnesota Mining and Manufacturing Company Figure 1 shows carrier 10 comprising a polymer film 12 with surface 14 having a low surface energy to which adhesive 16 and imaging stratum 18 have been applied.

If desired, for multi-color graphic patterns, one or more layers of imaging compositions or materials may be coated or printed on the imaging S stratum in desired pattern.

The imaging material can be comprised of conventional imaging materials used to form graphic images on substrates, such as inks, for example. The exact composition of the imaging material depends on the end use properties required. The imaging material ,i is typically applied from a wet composition having surface tension properties such that the composition will wet out and flow on the imaging stratum to form a film and provide a visible printed pattern thereon.

Imaging materials may be colored or colorless, although colored compositions are preferred. If desired, special effects may be achieved if the composition provides a product which is visible under ultraviolet light, but is colorless under ordinary ambient light. Conventional inks can be utilized, such as the vinyl or vinyl acrylic inks which are commercially available.

Screen printable inks can be classified on the basis of formation of an ink film, and the vehicles used for that film formation. For example, solvent-based inks form a film by evaporation of the various solvents contained therein, the wet film is dried. Curable inks provide a film which becomes polymerized through chemical change. Examples of inks include enamels; solvent-based inks, those containing lacquers and other solents, poster inks, and water-based inks; those containing 100 percent solids, such as those based on epoxies, ultraviolet exposure systems, plastisols, etc.; and specialty inks, such as those which ale expandable, those which exhibit electrical properties, etc.

To obtain good wetting, maximum surface contact on the imaging stratum, the surface tension of the ink must be equal to or less than the critical surface tension of the imaging stratum. In other words, the imaging stratum must have a higher degree of surface .a wetability than the imaging composition. However, the surface tension of the film formed by the imaging composition must be greater than that of the carrier surface such that the protective coatin, will properly dewet from the carrier surface to achieve desired registration with the graphic. If the surface tension Sof the film formed by the imaging composition is not sufficiently greater than that of the carrier surface, precise registration of the clear coat with the graphic pattern may not be achieved. Specific solvents, ,t l p.

7] -11surfactants, and other conventional and known additives can be utilized to modify the surface properties of the imaging composition, as desired.

Multiple imaging composition films, such as of different col>rs, may also be printed in sequence if desired.

The imaging stratum, imaging composition film, if any, and underlying adhesive are then trimmed in an imagewise fashion to provide the desired graphic pattern, such as by kiss cutting in imagewise fashion and removing undesired portions, weed. Care should be taken when kiss cutting because cutting too deeply, into the carrier, may tend to cause the clear coat composition to incompletely dewet from the carrier during drying, thus causing the final clear coat to only partially seal the edges of the graphic pattern and adhesive, whereas failure to cut deeply enough, not completely through the adhosive layer, may interfere with complete stripping of the weed. Figure 20 2 shows adhesive 16, imaging stratum 18, and imaging composition film 20 on carrier 10 after kiss-cutting and weeding to form the desired graphic pattern.

This invention relates to a process utilizing the surface tension characteristics of each of the four components of the process, the carrier surface, the imaging stratum, the imaging composition, if any, and the protective clear coat. Usually, one begins with a determination of the critical solid surface tension of the carrier surface and then tailors the other components to meet the requisite surface tension requirements. The surface energy of a fili cin be determined in a number of ways. For example, a series of liquids of known surface tension can bo applied to a smooth test surface. The contact anglo liquids on the solid surface is Measure information can then be plotted againr p p.

p P p

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It I *t 4 r' 2 l 1 w tension of the respective liquids. Extrapolation of such data to a zero contact angle provides the solid surface tension, that of the carrier surface, since at this point the surface tension of the solid film is approximately equal to that of the liquid.

This surface tension thus becomes the critical solid surface tension. When utilizing this procedure with a silicone-coated carrier, surface tension was calculated to be 23.8 dynes/centimeter, which is in agreement with the reported literature value of 24 dynes/centimeter.

Similarly, results of contact angle measurements for liquids having known values of liquid surface tension due to dispersion forces and polar forces, both of which contribute to surface free energy can be utilized.

Finally, wetting tension test kits are commerially available to determine the critical surface tension of specific film substrates.

Examples of typical surface tension values include about 32 dynes/centimeter for polyvinyl chloride films which can typically be corona treated to yield values of about 60 to 70 dynes/centimeter, and about 26 to 35 dynes/centimeter for typical vinyl inks which can Also be corona treated to yield surface energies of greater than 60 dynes/centimeter.

Once the critical solid surface energy of the carrier surface is known, an imaging stratum can be selected and an imaging composition can be tailored thereto to ptovide or produce a good graphic pattern which cain be clear coated with the desired precise or visually coincident registration.

Once the desired graphic pattern is appropriately formed on the carrier surface, the protective clear coat can be formulated based on solvent selection, particular resin, and other additives which together provide a formulation which is capable of wetting the dry graphic pjftern and exposed adhesive layer ft t 4 U, ft ft f ft bf *4 4A ft ft ft ft 4 4

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S -13sufficiently, and yet is not capable of wetting the carrier surface.

Other critical factors include the solvation of the coating composition and its rate of drying, in addition to its relative surface tension.

The protective clear coat is made typically of a resinous film-forming material, an example thereof being aliphatic polyurethanes, which are conventionally utilized today to provide a protective top coat for a transfer graphic image.

The liquid top coat is printed, as by screen printing, for example, over the graphic pattern, and slightly beyond the edge definition thereof, i.e., typically with an overprint margin up to about 2.54 millimeters (100 mils) wide, so as to assure complete coverage of the graphic pattern. As this liquid coat dries, it will dewet, creep or retract from the carrier where it has been overprinted onto the graphic pattern into precise registration therewith, and can 20 be cured in conventional fashion. Preferably, the liquid t E Sc: is printed at least 0.12 millimeter (5 mils) beyond the edge of the graphic pattern to ensure complete sealing of the edges of same and underlying adhesive.

Overprint margins of increasing width may cause the overcoat to puddle on the carrier or to bridge gaps V" within the graphic pattern, spaces between parallel strips such as are provided for 'racing" stripes used for automotive decoration.

S Accordingly, the protective clear coat provides S 30 a variable high thickness over the surface of the graphic pattern and seals the edges of the graphic pattern and underlying adhesive. Thus the clear coat protects the graphic pattern and underlying adhesive from chemical and environmental attack, thereby increasing the durability thereof, and also provides a unitary, paint-like appearance, thereby improving the attractiveness thereof.

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i:i -14- Preferably the final thickness of the clear coat is at least 0.01 millimeter (0.5 mil), and not greater than about 0.1 millimeter (4 mils). Thinner clear coats tend to provide less effective protection to the graphic pattern and underlying adhesive whereas those substantially thicker than the indicat:ed range may tend to give the graphic an undesirable artificial appearance.

Figure 3 shows the rounded profile provided by clear coat 22 after it has dried. The edges 24 of imaging stratum 18, underlying adhesive 16, and imaging composition film 20 have been sealed by clear coat 22.

Surprisingly, in addition to preventing collection of foreign matter at the edges of the transfer article, it has been found that the clear coat provides excellent solvent resistence to the graphic, particularly to the underlying adhesive. Thus it is preferred that S* the clear coat and underlying adhesive are mutually reactive to achieve an optimum seal. For instance, an isocyanate-containing clear coat composition and acrylic acid-containing adhesive wil] typically react to provide a chemical bond between the adhesive layer t' and clear coat, such a bond typically providing exceptional solvent resistance to the adhesive layer.

As shown in Figure 4, the article can then S be laminated to a conventional application tape 26, S" a flexible film 28 having a low-tack adhesive 30 thereon, whereupon imaging composition film S 30 imaging stratum 18, underlying adhesive 16, and overlying id protective coat 22 Oan be stripped away from the carrier S" 10, which cari then be discarded, and the transfer article then applied to a substrate. Following burnishing action, with a squeegee, the application tape is removed leaving the transfer article adhered to the substrate.

Figure 5 shows the transfer article adhered to substrate *1 n-- 32 after application tape 26 has been partially removed.

In this manner, there is provided a low profile, high performance, durable graphic transfer system, having special utility in the automotive market place.

For example, the invention can provide an automotive stripe or marking which is unique in appeara And performance properties, in that the graphics produced by the invention have rounded edges and closely similate paint, a technique not heretofor available with a transfer graphic system. Further, the graphics disclosed herein are very durable and resistant to forces typically encountered by autonobile finishes, abrasive action, dirt impact, and solvent attack.

The invention will now be further illustrated by the following illustrative examples, wherein all parts are by weight unless otherwise specified.

Example 1 A SCOTCHCAL Brand 3655 Film comprising a 20 polyvinyl chloride film coated with an acrylic «t t t tpressure-sensitive adhesive protected with a silicone i t t coated paper release liner was used as the imaging stratum, underlying adhesive, and carrier.

The film and underlying adhesive were hot kiss cut in an imagewise fashion ("racing" stripes) using a Teflon-coated, etched magnesium die at a temperature of 175 0 C to produce edges with a tapered profile.

The weed was then removed from the carrier to produce the graphic pattern.

A clear coat was then applied to the graphic pattern with an overprint margin of about 0.50 to millimeter (20 to 40 mils) using a 110 mesh screen.

The clear coat, a two component polyurethane, had the following formulation: 'I x B i; ~Bci 1 -16- Component Parts DESMOPHEN 651A-65 rigid polyester polyol; solids in ethyl glycol acetate; equivalent wt. of 325; hydroxyl of 5.2 (available from Mobay Chemical, Inc.) 46.5 DESMOPHEN 670-90 flexible polyester polyol; viscous liquid, 90% solids; equivalent wt. of 439; hydroxyl of 3.9 (available from Mobay Chemical, Inc.) 12.5 DESMDUR N-100 aliphatic polyisocyanate; viscous liquid, 100% solids; equivalent wt. of 190; NCO of 22 (available from Mobay Chemical, Inc.) 31.0 TINUVIN 770 hindered amine stabilizer (available from Ciba-Geigy, Inc.) 0.9 TINUVIN 328 benzotriazole UV absorber (available from Ciba-Geigy, Inc.) t C MULTIFLOW acrylic copolymer resin solution, solids in xylene; specific gravity 25/25 C of 0.925 0.940; refractive index at 25 C of 1.481 1.485 (available from Monsanto Industrial Chemicals Co.) 1.8 FC-430 fluorocarbon flow additive (available from 3M) CARBITOL ACETATE diethylene glycol monoethyl S 40 ether acetate (available from Union Carbide) 5.1 I t r The clear coat was cured at 75°C (165°F) for one hour.

An application tape was laminiated to the transfer graphic article.

The graphic was applied to a painted steel plate substrate.

The transfer graphic had rounded, unitary appearance similar to that of paint.

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The solvent resistance of the graphic was tested by soaking the graphic and substrate in a solution comprising 90 parts unleaded gasoline and 10 parts ethanol for about 40 minutes at room temperature. After being removed, the dried transfer graphic retained its initial, paint-like appearance, having suffered no apparent degradation.

Example 2 A transfer graphic was made and applied to a substrate as in Example 1.

Solvent resistance was tested by soaking the graphic and substrate in toluene for about 5 minutes at room temperature. After being removed and dried, the transfer graphic retained its initial, paint-like appearance, having suffered no apparent degradation.

14e s 444 Example 3 A transfer graphic article was made as in 1, except the clear coat was a lacquer acrylic material having the following formulation: Component CELLOSOLVE ACETATE ethylene glycol monoethyl ether acetate (available from Union Carbide) CARBITOL ACETATE diethylene glycol monoethylene ether etate (available from Union Carbide) ACRYLOID A-21 methyl methacrylate solid resin (available from Rohm and Haas) Example based Parts 40.3 24.4 18.6 t t 4 tIi C t t4 r 4 44 Butanol SANITIZER 160 butyl benzyl phthalate (available from Monsanto) 1/2 Sec-CAB cellulose acetate butyrate resin (available from Eastman Chemical) 3.7 5.6 7.4 ^1 -18- After application to a painted steel substrate, the transfer graphic also had a rounded, unitary appearance similar to that of paint.

Example 4 A transfer graphic article was made as in Example 1, except the clear coat was an ultraviolet curable material having the following formulation: Component Parts XP-173-09 aliphatic urethane acrylate oligomer diluted with 25 weight percent 2-ethylhexylacrylate (available from Cargill, Inc.) 64.3 Tetraethylene Glycol Diacrylate 21.7 n-Vinyl-2-Pyrrolidone 10.0 MULTIFLOW x, oL-diethoxyacetophenone (available from Upjohn Chemical, Co.) i The clear coat was applied to the graphic pattern with an overprint margin of about 5 to 125 mils (0.12 to 3.18 millimeters) using a 110 mesh screen.

The clear coat was cured by actinic radiation in a Linde PS-121 Photocure chamber at a beltspeed of 30 feet (9.1 meters) per minute in a nitrogen atmosphere.

After application to a painted steel substrate, the transfer graphic also had a rounded, unitary appearance similar to that of paint.

Example 3, A transfer graphic article was made as in Example 1, except an ink was screen printed onto the imaging stratum prior to kiss-cutting. The ink was SCOTCHCAL i Brand 3905 Ink, a polyvinyl chloride/vinyl acetate copolymer-based ink pigmented with carbon black. The ink was screen printed with a 230 mesh screen and cured pr F~ -19at 90°C (190°F) for 3 minutes.

After cooling to room temperature, a clear coat was applied thereto as in Example 1.

Following application to a painted steel substrate as in Example 1, the transfer graphic had a rounded, unitary appearance similar to two parallel stripes of paint, "racing" stripes.

Example 6 A polyester film was coated with the following silicone composition: Component SS-4191 (a 30 wt. solution of dimethyl polysiloxane in toluene) Toluene SS-4259C (an accelerator) SS-4192C (a silicone catalyst) Parts 15.0 83.0 .4 (The foregoing all being commercially available from the General Electric Company).

An ink composition was then screen printed on the silicone-coated polyester with a 110 mesh screen, the composition of the ink being: Component "VYHH" resin (an 87 wt. polyvinyl chloride/13 wt. polyvinyl acetate copolymer, available from Union Carbide) RAVEN 1200 (a carbon black pigment available from City Surface, Inc.) Dioctyl phthalate SF-96-1000 silicone flow agent available from General Electric Co.) FC431 (a fluorocarbon flow Cyclohexanone Isophorone Xylene Parts 22.0 7.8 4.3 0.3 31.2 31.2 2.7

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a I diluted with diisoamyl ketone to provide a viscosity of 1300 cps (using a Brookfield viscometer No. 3 spindle).

After printing, the solvents were evaporated by heating in an air convection oven at 75 0 C (165 0

F).

A protective clear coat having the same formulation as that used in Example 1 was diluted with CARBITOL ACFTATE to a viscosity of 500 cps (using a Brookfield viscometer, No. 3 spindle).

This formulation was then screen printed over the previously prepared ink image with an overprint margin of about 0.50 millimeter (20 mils).

The construction was then baked for two hours at about 75 0 C (165 0 During drying, the coating composition dewetted back to the edges of the ink image, thus providing excellent registration with the underlying ink areas and an attractive, paint-like appearance.

An application tape, 25-508-LC, available froi Laminated and Coated Products, Inc., comprising a 0.06 millimeter (2.5 mil) polyethylene backing coated with a low-tack, water-based acrylic pressure-sensitive I adhesive, was laminated to the polyester film over the coated graphic pattern. The polyester film was removed, transferring the graphic pattern from the polyester film to the application tape.

The underside of the graphic pattern and <exposed portiorn of the low-tack adhesive on the application tape were corona treated using 500 Watts at a speed of 6.1 meters (20 feet) per minute.

An adhesive formulation, comprising 19.6 weight percent adhesive polymer (isooctyl acrylate/vinyl S acetate/acrylic acid in a 74/22/4 weight ratio) and 80.4 weight percent ethyl acetate, was prepared by mixing the ingredients together at room temperature; coating the solution onto a silicone-coated, white polyethylene film, 05-4-HiD-ST6A/ST3A-White available from Schoeller Release Products, Inc., to a wet thickness

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S 1 "-21of about 0.8 millimeter (3 mils); and evaporating the solvent by heating for five minutes at 75 0 C (165 S. The adhesive-coated side of this film was laminated to the corona-treated side of the application tape and graphic pattern.

The silicone-coated polyethylene film was removed and the article placed on a painted steel substrate such that adhesive was in contact with the painted steel. Moderate pressure was applied to the application tape by stroking that surface with the edge of a polyethylene squeegee over the film structure. The application tape was then peeled from the substrate.

The graphic design remained on the painted steel substrate and any adhesive not in registration with the graphic article remained on the application tape.

The solvent resistance of the article was then tested by immersion in a gasoline/ethanol mixture as in Example 1. After removal and drying, the graphic 0 article was inspected to reveal disfiguring solvent attack along the edges thereof. The ink image had become twa, rippled and rough along the edges thereof and the *trr underlying adhesive in such areas had been leached out.

Comparative Exaple A A continuous layer of the protective clear coat composition described in Example 1 was applied to SCOTCHCAL I$rand 3655 Film by screen printing the composition through a 110 mesh screen. The clear coat was cured at 750C (165o°) for one hour.

The clear coat, film, and underlying adhesive Swere hot kiss-cu in an imagewise fashion ("racing" stripes) using a Teflon-coated, etched magnesium die at a temperature of 175 0 C (350°F).

The weed was ther .~tmoved from the carrier to produce a graphic aticlO. The edges of the article

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-22did not have a rounded profile such as would suggest a paint-like appearance.

An application tape was laminated to the graphic article, and the article was applied to a painted steel substrate as in Example 1.

The solvent resistance of the graphic was then tested by immersion in a gasoline/ethanol mixture as in Examples1 and mn""m After removal and drying, the graphic was inspected whereupon it was observed that the adhesive had oozed from underneath the graphic pattern.

In each of Examples 1-6, all examples of the invention, the graphic articles produced had rounded profiles and a paint-like appearance. Comparison of the results of Examples 1 and 2, preferred embodiments of the invention, with those of Example 6 and Comparative Example A illustrates the solvent resistance achieved by a preferred transfer graphic of the invention wherein S. the protective clear coat seals both the graphic pattern 20 and underlying adhesive and the improved solvent resistance attained as compared to that of transfer graphics wherein the clear coat is applied only to the graphic pattern and not to the exposed edges of the underlying adhesive.

Various modifications and alterations of this invention will become apparent to those skilled in the art without departing from the scope and spirit of this invention.

1 1 i /1

I

Claims

2. The article of claim 1 further characterized in that said graphic pattern comprises a film.
3. The article of claim 2 further characterized in that said graphic pattern further comprises a film of at least one imaging composition which covers at least a portion of the surface of said graphic pattern,
4. The article of one of claims 1-3 further characterized In that said protective clear coat comprises an allphati(: polyurethane. The article of any one of claims 1-4 further characterized in that said protective clear coat Is curable with ultraviolet radiation.
6. The article of any one of claims 1-5 further characterized in that said protective clear coat has reacted witl said adhesive,
7. The article of claim 6 further characterized in that said u protective clear coat contains an isocyanate IIW and said adhesive contains acrylic acid.
8. The article of any one of claims 1-7 further characterized in that said article comprisis a release liner.
9. The article of claim 8 further characterized in that said article comprises an application tape. A process for preparing a graphic pattern on a substrate having a protective coating thereover and in exact registration therewith, characterized in that said proces comprises: 1) providing a carrier film having a major surface thereon; 2) applying at least one coating of an imaging composition on said major surface, said imaging composition having a sufficient surface tension to wet said major surface of said carrier and provide a film of said 1 graphic pattern thereon; 3) drying said coating of imaging composition to form said graphic pattern; 4) applying a liquid protective coating over said graphic pattern, beyond the edge definition thereof and in substantial registration therewith; said protective coating having sufficient surface tension to wet said graphic pattern, but not said major surface of said carrier film; and drying said liquid protective coating; whereby during said drying said protective coatinf) will dewet and retract from said major surface of said carrier onto said graphic pattern and provide exact registration with said graphic pattern.
11. A process for preparing a dry transfer article capable of transfer of a rahlc pattern to a substrate, said graphic pattern having a protective coating thereover in precise registration therewith which seals underlying adhesive, characterized in that said process comprises: A) providing a carrier having a major surface thereon; KSP/389U -24- E I I .9 99 o 9~9 99 9 9 999 9 o 99 99 9 999 0 9999 9 9 99* U 99 9 9 9 II 99 9 9 99 U $9 99 9 9 99 9 *4 99 9 I 99 99 9 94~' 9 99 1 99 9 99 B) coating an adhesive layer thereon; applying an imaging stratum thereover; D) trimming said imaging stratum and underlying adhesive in an imagewise fashion to provide a graphic pattern; E) applying a liqqld protective coating over said graphic pattern, beyond the edge definition thereof and in substantial registration therewith; said protective coating having sufficient surface tension to wet said graphic pattern and exposed adhesive, but not said major surface of said carrier film: and F) drying said protective coating; whereby during said drying said protective coating will dewet and retract from said major surface of said carrier and provide precise registration with said graphic pattern, sealiig the edges of same and said underlying idhesive.
12. The process of any one of claims 10 or 11 further characterized in that said carrier film is a polyester.
13. The process of any one of claims 10 or 11 further characterized In tht said major surface has a low surface energy coating theraon.
14. The process of claim 13 further characterized in that said low surface energy coating is a silicone,
15. The process of claim 11 further characterized in that at least one layer of an imagiig composition KSP/389U (4 "if 'p 1 -26- is applied to said imaging stratum in imagewise fashion.
16. The process of any one of claims 10 or further characterized in that said imaging composition comprises an ink.
17. The process of claim 16 further characterized in that said ink is selected from the group consisting of vinyl and vinyl-acrylic inks.
18. The process of any one of claims 10 or 11 further characterized in that said protective coating composition comprises an aliphatic polyurethane.
19. The process of any one of claims 10 or 11 further characterized in that said protective coating composition is curable with ultraviolet radiation. The process of any one of claims 10 or 11 further characterized in that said process comprises the step of curing said protective coating after the drying thereof.
21. The process of claim 11 further characterized in that said protective overcoating is reactive with said adhesive.
22. The process of claim 21 further characterized in that said liquid protective coating comprises an isocyanate and said adhesive layer comprises acrylic acid.
23. An article produced by the process of claim 10 or 11. 1 i i $1 I- 'Ir i 27 Ua
24. A dry transfer article for applicatiJn to a substrate to provide Sdesign thereon, as defined in claim 1 and substantially as described herein with reference to and as illustrated by the accompanying drawings and/or the Examples other than comparative Examples. A process for preparing a graphic pattern on a substrate as defined in claim 10 and substantially as described herein with reference to and as illustrated by the accompanying drawings and/or the Examples other than comparative Examples.
26. A process for preparing a dry transfer article substantially as defined in claim 11 as described herein with reference to the accompanying drawings and/or the Examples other than comparative Examples. DATED this SEVENTEENTH day Oi JULY 1989 Minnesota Mining and Manufacturing Company *1 9P *tu g di *7 ri4 4 a Patent Attorneys for the Applicant SPRUSON FERGUSON i i IAD/870h