United States Patent 1
`Spain et al.
`
`[54] DRY PAINT TRANSFER PROCESS FOR
`MAKING HIGH DOI AUTOMOTIVE BODY
`PANELS
`
`{75]
`
`Inventors: Patrick Leon Spain, Lowell; Keith
`Lawson Truog, Crown Point, both of
`Ind.
`
`[73] Assignee: Avery Dennison Corporation,
`Pasadena, Calif.
`
`US005725712A
`
`{11] Patent Number:
`
`[45] Date of Patent:
`
`5,725,712
`Mar. 10, 1998
`
`FOREIGN PATENT DOCUMENTS
`
`0109313
`0133119
`0177829
`0178096
`0230364
`0251546
`
`5/1984 European Pat. Off. .
`2/1985 European Pat. Off. .
`4/1986 European Pat. Off.
`.
`4/1986 European Pat. Off.
`.
`7/1987 European Pat. Off.
`.
`1/1988 European Pat. Off. .
`
`(List continued on next page.)
`
`OTHER PUBLICATIONS
`
`[21] Appl. No.: 402,960
`
`(22] Filed:
`
`Mar. 13, 1995
`
`Fuchs, SME Technical Paper No., FC 77-647, “A State of
`the Art—Evaluation of Hot Stamping Decorative Plastic,”
`dated 1977.
`
`Related U.S. Application Data
`
`(List continued on next page.)
`
`[63] Continuation of Ser. No. 346,548, Nov. 29, 1994, which is
`a continuation of Ser. No. 179,765, Jan. 10, 1994, aban-
`doned, which is a continuation of Ser. No. 25,827, Mar. 3,
`1993, abandoned, which is a continuation of Ser. No.
`873,708, Apr. 22, 1992, abandoned, whichis a continuation
`of Ser. No. 424,302, Nov. 22, 1989, abandoned, which is a
`continuation-in-part of Ser. No. 162,917, Mar 2, 1988,
`abandoned, which is a continuation-in-part of Ser No.
`31,984, Mar. 27, 1987, abandoned.
`
`Tint. C06 cccccccsssssscssecsccerscssseseececenssanecees B32B 31/00
`G51]
`[52] US. C0. eeecccscssssssesstssecsee 156/230; 156/231; 156/239;
`156/245; 156/246
`[58] Field of Seared .....ccccessscscssssesssssserssees 156/230, 231,
`156/233, 235, 238, 240, 245, 239, 196,
`246; 428/200, 201, 202, 203, 204
`
`[56]
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`5/1939 Gaylord, Jr. oseesssesscoesssecssseae 41/33
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`4/1961 Barkhuff, Jr. et al.
`wee 18/59
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`
`3,057,018 10/1962 Lawrence etal......
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`
`3,458,391
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`8/1969 Schmitt.....
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`
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`293/71
`
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`
`7/1972 Conley et ab. nn.eeesscccenteee 156/245
`3,679,510
`
`Primary Examiner—James Engel
`Attomey, Agent, or Firm—Christie, Parker & Hale, LLP
`
`[57]
`
`ABSTRACT
`
`An automotive quality paint coat is laminated to the exterior
`surface of a molded plastic car body panel. In one
`embodiment, the paint coat includes an exterior clear coat
`above a color coat. The clear coat and color coat are each
`coated on a temporary fiexible casting sheet and dried. A
`high gloss surface is transferred to the clear coat from the
`casting sheet. The paint coat is then transferred from the
`casting sheet to a thin, semi-flexible thermoformableplastic
`backing sheet by dry paint transfer-laminating techniques.
`The resulting laminate is thermoformed into a complex
`three-dimensional shape of the car body panel. The pre-
`formed laminate is then bonded to a plastic substrate mate-
`rial by injection-cladding techniques to form the finished
`article. The paint coat has sufficient elongation to retain
`exterior automotive appearance and durability properties
`during thermoforming without deglossing. The backing
`sheet absorbs defects in the substrate material so the paint
`coat retains its appearance and durability properties. The
`finished article comprises a high gloss, defect-free paint coat
`on the exterior of a molded plastic car body panel. Solution-
`form polyvinylidene fiuoride/acrylic paint systems have
`remarkably high combined gloss and distinctiveness-of-
`imagelevels and durability properties.
`
`(List continued on next page.)
`
`66 Claims, 5 Drawing Sheets
`
`
`
`SLECOAT
`
`CLG COM
`
`YEAR COAT
`
`CARRIE
`
`
`EX1070
`Yita v. MacNeil
`
`IPR2020-01139
`
`EX1070
`Yita v. MacNeil
`IPR2020-01139
`
`

`

`5,725,712
`Page 2ee—
`
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`
`3,880,690
`3,949,139
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`4,248,762
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`4,307,058
`4,314,004
`4,317,860
`4,349,592
`4,359,504
`4,364,886
`4,369,157
`4,396,680
`4,415,519
`4,451,522
`4,451,597
`4,474,845
`4,499,151
`4,515,649
`4,578,426
`4,595,551
`4,605,596
`4,639,341
`4,643,789
`4,769,100
`4,810,540
`4,818,589
`4,828,637
`4,838,973
`4,868,030
`4,902,557
`5,114,789
`5,342,666
`
`4/1975 Fuchs et all.
`.......ccsssccrsensseessees 156/242
`
`4/1976 Dunninget al. wees
`vee 428/328
`.......sscsessnseeess 428/31
`JFA9TS Dumming et all.
`
`6/1980 Chang .........02
`. 428/416
`
`11/1980 Van Manen et al.
`...........sereseree 428/31
`2/1981 Homibrook et al.
`....
`. 260/42.22
`
`
`wee 156/238
`4/1981 Rampelberg.....
`6/1981 Dani .............
`- 4281
`12/1981 Morello et al.
`264/510
`2/1982 Stoneberg .....
`. 428/421
`
`....
`- 428/421
`3/1982 Strassel
`
`9/1982 Nussbaum .
`- 4281
`428/403
`11/1982 Troy
`
`.
`a 264/171
`12/1982 Strassel
`1/1983 COMET sccccccssccsssccescccsseccsenseeee 264/246
`
`B/1983 Chang .....crscssvscsssssreraessacsssersees 428/421
`
`LU/1983 Strassed .....sssssssasseeeneesesrernees 264/171
`
`5/1984 deVroom..
`. 428/201
`
`5/1984 Victorius ..
`.. 524/39
`
`10/1984 Hagerman et al.
`..
`.-- 428/283
`2/1985 Dowbenkoetal. .
`we 428/447
`5/1985 Nussbaum ........
`156/244.11
`BAL9B6 Lenz et al.
`cccccccccccsscssssssressseers 525/131
`6/1986 Maurer sassssosssssssssenssnsesereeee 264/321
`8/1986 Fry
`.. 428/423,3
`1/1987 Hanamoto et
`we 264/40.1
`2/1987 Parker et al.
`........cccscssoseseseerees 156/219
`9/1988 Short et al.
`......
`- 156/285
`...
`~- 428/31
`3/1989 Ellison et al.
`
`..
`ww. 428/201
`4/1989 Johns
`t al.
`5/1989 Mentzerea. wr 156212
`
`seessccrsssssesee 156/212
`6/1989 Mentzeret al.
`
`.
`| 428/174
`9/1989 Mentzer et al.
`
`2/1990 Rohrbacher ..
`| 428/215
`
`. 428/328
`5/1992 Reatfler.....
`
`.nccccesssssscsscsssssesoee 428/46
`8/1994 Ellison et al.
`
`
`
`FOREIGN PATENT DOCUMENTS
`
`0266107
`0266109
`50-19132
`
`5/1988 European Pat. Off. .
`5/1988 European Pat. Off. .
`TAYT9
`Japan .
`
`Japan .
`54-127464 10/1979
`Japan .
`54-33561
`11/1979
`Japan .
`56-140064
`3/1983
`Japan .
`59-135231
`8/1984
`Japan.
`59-227447
`11/1984
`Japan.
`59-120432 12/1984
`Japan.
`61-008349
`1/1986
`1232971
`5/1971 United Kingdom .
`2084513
`4/1982 United Kingdom .
`8100233
`2/1981 WIPO.
`
`OTHER PUBLICATIONS
`Dotymers Paint Colour Journal, Oct. 29, 1980, p. 796.“The
`:
`.
`:
`:
`:
`:
`Orientation of Aluminum Pigments in Automotive Fin-
`ishes,” Toyo Aluminum KK.
`Automobiltechnische Zeitschrift, vol. 84, No. 5, May 1982.
`Chemical Week, Jul. 4, 1984, p. 30 “Automotive Coatings:
`Helping Detroit Woo Customers”.
`Anonymous, “Research Disclosure,” Jul. 1984.
`Ullman, et al., “Composites, Science and Technology,”
`1985, pp. 97-112.
`BP&R, Nov. 1985, pp. 29-30.
`:
`‘
`aos
`:
`:
`Avery International Thermark, “The Driving Force in Lami-
`_—ihates,” 1985.
`;
`;
`Plastics World, “Composite Structures: Next Wave in
`Detroit,” Miller, Nov. 1986, pp. 30-34.
`“Brilliant Performance,” Rexham Corporation, dated 1987.
`Plastics Engineering, “Solvent Cast Films”, May 1987, pp.
`29-33.
`orthr
`‘
`‘Afdavit of VictorH,Rampelberg
`and supporting exhibits
`.
`neaaranry alee 8
`Japanese Opposition by Minnesota Mining and Manufac-
`turing Co.
`against
`Japanese Patent Application No.
`63504355 andattached exhibits.
`Japanese Opposition by Rexham Industries Corp. against |
`Japanese Patent Application No. 63-504355 and attached
`exhibits.
`Japanese Opposition by Nissha Printing Co., Ltd. against
`Japanese Patent Application No. 63-504355 and attached
`exhibits.
`
`:.
`
`

`

`US. Patent
`
`Mar. 10, 1998
`
`Sheet 1 of 5
`
`5,725,712
`
`i. aNwe! KESZe
`
`
`
`
`SARAEORNAAD
`CALQRCOAT
`PELALALALALALTLLL
`CLLAR COAT
`LARBEV.EEEREREBES
`VILL LLILKELPLp
`
`

`

`US. Patent
`
`Sheet 2 of 5
`
`Mar. 10, 1998
`
`5,725,712
`
`

`

`U.S. Patent
`
`Mar. 10, 1998
`
`Sheet 3 of 5
`
`5,725,712
`
`CLEAR COAT
`COLOR COAT—
`
`SIZE COAT
`BACKING SHEET-
`
`
`
`
`
`
`

`

`USS. Patent Mar. 10, 1998
`
`Sheet 4 of 5
`
`5,725,712
`
`SSx
`
`AWA
`
`\
`
`
`
`TILAOLNNN)
`LPTffGELEEEEFhf
`HE °
`VN
`
`
`
`

`

`U.S. Patent
`
`Mar. 10, 1998
`
`Sheet 5 of 5
`
`5,725,712
`
` SSO7
`
`
`

`

`5,725,712
`
`1
`DRY PAINT TRANSFER PROCESS FOR
`MAKING mGB DOI AUTOMOTIVE BODY
`PANEIS
`
`This is a division of Ser. No. 08/346,548 filed Nov. 29,
`1994, which in tum is a continuation of Ser. No. 08/179,765
`filed Jan. 10, 1994, now abandoned, which in turn is a
`continuation of Ser. No. 08/025,827 filed Mar. 3, 1993, now
`abandoned, which in tum is a continuation of Ser. No.
`07/873,708 filed Apr. 22, 1992, now abandoned, which in
`tum is a continuation of Ser. No. 07/424,302 filed Nov. 22,
`1989, now abandoned, which in tum is a continuation-in(cid:173)
`part of Ser. No. 162,917 filed Mar. 2, 1988, now abandoned,
`which in tum is a continuation-in-part of Ser. No. 031,984
`filed Mar. 27, 1987, now abandoned.
`
`FIELD OF THE INVENTION
`
`This invention relates generally to dry paint transfer
`techniques, and more particularly to the use of these tech(cid:173)
`niques to produce exterior plastic car body members or
`panels with a paint coat applied in a separate production
`operation which can eliminate or greatly reduce the painting
`steps carried out in the manufacturing operations of a
`conventional automobile production plant.
`
`BACKGROUND
`Automotive design and manufacture present a unique set
`of problems in the selection of materials and processes used
`in the manufacture of automobile bodies. As a form of 30
`transportation, automobiles are unique because most buyers
`want a vehicle to have a certain individual styling. A recent
`trend in the automobile industry is toward production of
`distinctive vehicles styled to attract specific groups of con(cid:173)
`sumers. This change has required the car builder to shift
`production from a few models manufactured in large vol(cid:173)
`umes to a larger number of more distinctive body styles.
`These developments have demanded from the manufacturer
`both styling flexibility and reasonable tooling costs for each
`body style.
`For many years, car body members and panels have been
`made predominantly from sheet metal. However, car build-
`ers now generally recognize that future use of plastics for
`exterior car body members and panels, rather than sheet
`metal, may provide a solution to meeting the demand for
`more unique body styling and reduced tooling costs. With
`the increasing concern for weight-reduction, car builders
`have also turned their attention to the use of plastics as an
`alternative to heavier metal parts. For instance, certain
`exterior car body parts of many automobiles now on the road so
`are made from lighter-weight plastic. These parts include
`bumpers, rocker panels, fender extensions, window and door
`moldings, and the like.
`As reported in plastics World, November, 1986, p. 30 et
`seq., a number of advanced corporate development pro(cid:173)
`grams now in process are also seeking solutions to the
`problem of commercially manufacturing from plastics the
`larger exterior car body panels such as hoods, roofs, deck
`lids, and in fact, the entire car body, if possible. The concept
`of making a production car body from a material other than
`sheet metal dates back to at least as early as the mid-1950' s,
`when the Chevrolet Corvette was first manufactured with a
`fiberglass body. Developments in plastic resin technology in
`recent years have resulted in more sophisticated plastic
`materials of higher impact strength than fiberglass. Polycar(cid:173)
`bonates are an example. These developments in plastics
`technology have caused many plastics manufacturers, for
`
`2
`about the last decade or so, to seek solutions to the problem
`of commercially producing the entire car body at a reason(cid:173)
`able cost from these later-developed high-strength plastic
`materials. Recent development efforts have also been
`5 directed toward producing plastic car bodies from various
`alternative plastics molding processes, including use of
`SMC (sheet molding compounds) and RIM (reaction injec(cid:173)
`tion molding) techniques.
`Development of a production process for making exterior
`10 car body members and panels from plastics requires solu(cid:173)
`tions to a number of technical problems. These parts must be
`manufactured at reasonable costs for tooling, assembly and
`materials. The end product also must meet certain quality
`requirements. For instance, the resulting car body panel
`15 must have structural capabilities such as impact strength and
`resistance to mechanical stress necessary to compete with
`sheet metal. It must also have a paint coat with a defect-free
`and durable exterior surface. An automotive quality paint
`coat must meet certain specifications for a large number of
`20 physical properties in order to be capable of use as an
`exterior automotive paint coat. These properties include
`gloss; distinctiveness-of-image; hardness; abrasion resis(cid:173)
`tance; weatherability such as lN resistance; impact
`strength; thermal stability, namely, resistance to extreme
`25 high and low temperatures; gasoline and acid resistance;
`cleanability; adhesion to the underlying car body panel;
`resistance to water and humidity exposure; and hiding
`ability or opacity of the paint coat
`In the past, a conventional production process for apply(cid:173)
`ing an exterior paint coat to car bodies made of sheet metal
`has involved transporting the preformed auto bodies to
`application lines in the plant where the car bodies are dipped .
`in paint, followed by transporting them to a separate location
`for baking the paint coat and waiting until the hardened paint
`35 coat dries thoroughly. Most paint systems today are acrylic
`enamels which are cross-linked into a hard, glossy, durable
`paint coat during baking. Following painting, the car bodies
`are transported back to the production plant for further
`assembly operations. The painting of plastic car body mem-
`40 hers has typically involved manually spray painting the
`plastic parts in a separate painting facility, followed by
`drying, and then transporting the finished parts back to the
`assembly operation. Conventional painting of sheet metal
`car bodies and plastic parts is expensive and is a significant
`45 factory problem with respect to environmental protection,
`workcrs'safety, corrosion treatment, and waste disposal. It is
`estimated that about one third of the total capital investment
`in an automobile production facility today is involved in
`painting car body members and panels.
`In recent years, metalized laminating techniques have
`been used for forming a reflective, weather-resistant metal
`surface on molded plastic automotive trim parts. These
`techniques have not yielded plastic trim parts with a paint(cid:173)
`coated surface capable of exterior automotive use. Such
`55 plastic trim parts have experienced difficulties in maintain(cid:173)
`ing reflectivity and avoiding surface defects under mechani(cid:173)
`cal impact and environmental exposure.
`New car body applications of molded plastic materials
`can develop if the manufacturer can find a way to commer-
`60 cially produce plastic car body panels with a paint coat
`having the durability and appearance properties necessary
`for exterior automotive use. Moreover, if in-mold painting or
`coating processes can be developed as an alternative to
`conventional auto painting, then auto assembly plants can be
`65 more compact, and capital costs and environmental and
`safety problems associated with conventional car painting at
`the factory site can be avoided.
`
`

`

`5,725,712
`
`4
`dimensional shapes without cracking, deglossing, producing
`stress lines or other surface non-uniformities, or otherwise
`degrading the finish. Large pigment levels also adversely
`affect the strength and alter elongation properties of the paint
`s coat. In addition, reliable bonding of the paint coat to the
`laminate and bonding of the laminate to the underlying
`substrate material are essential.
`Thus, the desired paint system should have a critical
`combination of many physical properties in order to produce
`10 a surface capable of exterior automotive use, while retaining
`desired surface characteristics after the laminating, thermo(cid:173)
`forming and injection-cladding or molding steps have been
`carried out. However, some physical properties tend to be
`mutually incompatible in such a process. For instance, a
`15 paint system may have good qualities of durability such as
`hardness, toughness, weatherability and the like; but the
`same paint system may not have sufficient elongation to be
`heat-formed into a complex shape without cracking or
`otherwise losing its durability properties. Other paint sys-
`20 terns may degloss when heat-formed into a complex shape.
`Some paint systems have sufficient elongation to permit
`thermoforming into the desired complex shape, but they are
`too soft and therefore lacking in the necessary hardness or
`durability properties.
`In summary, there is a need for an economical production
`process for manufacturing highly contoured molded plastic
`exterioc car body members or panels with a laminated paint
`coat having both the durability and the gloss and other
`appearance properties sufficient for exterior automotive use.
`Laminating techniques for applying a paint coat to such a
`molded plastic part can provide a valuable alternative to
`conventional painting of exterior car body members. Certain
`properties, such as glass-smooth, defect-free surfaces and
`uniform paint coats, are better produced by laminating
`techniques than by conventional painting. Capital costs also
`can be reduced and environmental problems can be allevi-
`ated. Laminating techniques require, in addition, however, a
`paint system and processing techniques capable of produc(cid:173)
`ing and maintaining, throughout processing, the durability
`and elongation properties, opacity, gloss and distinctiveness(cid:173)
`of-image levels, and defect-free surface necessary for exte-
`rior automotive applications. The present invention solves
`these problems.
`
`3
`Many corporate product development efforts have sought
`alternatives to conventional painting of molded plastic exte(cid:173)
`rior car body panels and parts, but without any known
`success to date. A number of problems must be overcome to
`develop an economical production-type paint system and
`JIOCess for applying a paint coat capable of exterior auto(cid:173)
`motive use for molded plastic exterior car body panels and
`parts so as to eliminate conventional spray painting opera(cid:173)
`tions. For instance, use of the cross-linked acrylic enamel
`paint systems which are commonly baked on the sheet metal
`car bodies to produce a tough, glossy finish cannot be used
`in painting plastic car bodies because of temperature limi(cid:173)
`tations. One approach, which is the subject of this invention,
`involves developing a paint-coated laminate which can be
`used to replace the conventional painted finish on the
`exterioc of an automobile body. The laminate is made from
`a paint coat applied to a casting sheet by paint coating
`techniques. The dried paint coat is then transferred from the
`casting sheet to a laminate panel by dry paint transfer
`techniques. The coating operation permits use of high tem(cid:173)
`perature resistant paint systems capable of producing a
`tough, glossy finish. The laminate is later thermoformed into
`a complex three-dimensional shape and then bonded or
`integrally molded to an underlying plastic car body member
`oc panel. Injection-cladding techniques can be used to manu- 25
`facture a molded plastic part and simultaneously bond the
`laminate to the exterior of the molded plastic part.
`A number of technical problems must be overcome in
`ocder to use such a laminate in a thermoforming and
`injection-cladding Jiocess, while maintaining a defect-free 30
`painted surface with high gloss and durability properties
`throughout the thermoforming and injection-cladding steps.
`For instance, the laminate must be heat and vacuum(cid:173)
`fonnable into a complex three-dimensional shape without
`cracking, deglossing, stress whitening or creating other 35
`surface defects. A paint coat on such a laminate can require
`a substantial amount of pigment in order to provide the
`necessary coloc density or opacity and distinctiveness-of(cid:173)
`image. However, it has been found that use of pigments in
`a paint coat can cause deglossing of the surface when a 40
`paint-coated laminate is thermoformed. Deglossing may
`even occur in a nonpigmented clear coat during thermo(cid:173)
`forming.
`In addition to surface gloss requirements, the finished
`paint coat must be defect-free. Defects must not be produced
`by the thermoforming step, and the laminate also must be
`bonded or molded to the underlying plastic substrate in a
`manner that hides any defects that may be present in the
`substrate material.
`Moreover, a finished paint coat may have a reasonably
`high surface gloss, but still not have the desired visual
`appearance known as distinctiveness-of-image. This prop(cid:173)
`erty relates to the mirror-like character of the finish and is
`measured by the clarity of an image reflected by the finished
`surface. It is difficult, in a thermoforming operation, to
`produce an exterior automotive paint coat with a high gloss
`level and a high distinctiveness-of-image.
`Durability properties are also critical in producing a paint
`coat capable of exterior automotive use. The paint coat must
`avoid exhibiting defects when exposed to mechanical impact
`and avoid deterioration of the surface from exposure to
`chemicals and to the weather.
`A paint system that produces the toughness or hardness
`necessary for exterior automotive use also must have the
`elongation properties and heat resistance necessary to allow
`thermoforming of the paint coat into complex three-
`
`45
`
`SUMMARY OF THE INVENTION
`
`Briefly, one embodiment of this invention provides a
`process for manufacturing a molded plastic article having a
`finished paint coat with surface properties meeting criteria
`50 for exterior automotive use. These include properties pro(cid:173)
`viding predetermined durability, gloss and other appearance
`characteristics in the finished paint coat. In this process, the
`paint coat is applied to a three-dimensionally shaped exterior
`surface of an intermediate laminate by a combination of
`55 paint coating, dry paint transfer-laminating, and thermo(cid:173)
`forming techniques. The thermoformed laminate then can be
`bonded to or molded to an underlying plastic substrate, for
`example, by injection-cladding techniques, with the paint
`coat maintaining properties sufficient for exterior automo-
`60 tive use throughout these processing steps. The invention is
`described herein in the context of a paint coat applied to the
`surface of a plastic car body member or panel, but the
`invention is also applicable to other articles of manufacture
`having a paint coat with properties similar to those required
`65 for exterior automotive use.
`Considering the application of the invention to a process
`for making a plastic exterior car body panel, a paint coat
`
`

`

`5,725,712
`
`5
`comprising a synthetic resinous ~erial is coated in ~n(cid:173)
`film form onto a flexible, heat-resistant temporary casting
`sheet The paint coat is dried on the sheet sufficiently to
`harden it and transfer a predetermined exterior surface gloss
`level from the casting sheet to the paint coat The paint coat
`may comprise a clear coat and a separate pigmented color
`coat The clear coat and color coat may be formed as
`separate thin-film coatings which are dried and then bonded
`to one another. The color coat, in combination with the clear
`coat, provides a composite paint coat having the durability,
`gloss and other appearance properties necessary for e~~or
`automotive use. The paint coat is transferred to a semmgid,
`thermoformable synthetic resinous backing sheet so that the
`paint coat provides the exterior surface of the paint-coated
`backing sheet The laminate formed by the backing sheet
`and the bonded paint coat is thereafter thermoformed to
`produce a three-dimensionally shaped preformed laminate,
`while still retaining durability, gloss and other appearance
`properties necessary for exterior automotive. applicatio_ns.
`The thermoforming step can produce substantial elongation
`of the paint coat The paint coat is capable of elongating
`from about 50% to about 150%, or more, during
`thermoforming, without significant loss of its exterior auto(cid:173)
`motive durability, gloss and other appearance properties. In
`a subsequent injection-cladding step, for example, a syn(cid:173)
`thetic resinous substrate material is injection molded behind
`the preformed paint-coated laminate to bond the laminate to
`the substrate. This forms a molded plastic article with a
`painted surface which retains the exterior automotive sur(cid:173)
`face characteristics. The substrate can be an exterior body
`panel of a motor vehicle. The substrate material normally
`may have a substandard surface finish, but the backing sheet
`absorbs surface defects in the substrate material during the
`injection-cladding step so as to retain the minimum surface
`defect level and gloss required of an exterior automotive
`paint coat
`In one embodiment, the paint coat comprises a fluorinated
`polymer and acrylic resin-containing paint system with
`thermoplastic properties. The relative amounts of the flu(cid:173)
`orinated polymer and acrylic resin components in the paint
`coat formulation provide a sufficient level of resistance to
`deglossing and sufficient elongation for the laminate to be
`thermoformed into complex three-dimensional shapes while
`providing sufficient durability and appearance properties for
`the finished product to be useful as an exterior automotive 45
`body member or panel.
`In one embodiment in which the paint coat comprises an
`exterior clear coat and an underlying color coat bonded to
`the clear coat, the clear coat can be formed from a fluori(cid:173)
`nated polymer and acrylic resin-containing coating. In this 50
`case, the clear coat can provide the majority of the durability,
`gloss and other appearance properties necessary for use as
`an exterior automotive paint coat The color coat also can
`comprise a thermo-plastic fluorinated polymer and acrylic
`resin-containing paint system. Other paint systems compat- 55
`ible with the clear coat and the backing sheet also can be
`used.
`In one form of the invention, the fluorinated polymer
`component comprises polyvinylidene fluoride (PVDF), and
`the acrylic resin component can be a polymethyl methacry- 60
`late resin, a polyethyl methacrylate resin, or mixtures
`thereof, including copolymers thereof. One finished product
`having a surface capable of exterior automotive use is made
`from a paint system comprising from about 50% to about
`70% PVDF and from about 30% to about 50% acrylic resin, 65
`by weight of the total PVDF and acrylic solids, exclusive of
`the pigment
`
`6
`This invention also provides an exterior automotive qual(cid:173)
`ity paint coat having unusually high gloss and
`distinctiveness-of-image (DOI) along with other durability
`properties sufficient for exterior automotive use. This
`5 embodiment of the invention includes a thermoformable
`laminate having a paint coat bonded to it in which the paint
`coat, prior to casting on a casting sheet, was prepared as a
`solution of vinylidene fluoride in acrylic resin. The paint
`coat comprises at least a clear coat of vinylidene fluoride and
`10 acrylic resin coated from solution, which produces thermo(cid:173)
`formed laminates with high combined gloss and DOI levels.
`Good combined gloss and DOI levels have been obtained
`experimentally when the clear coat and pigmented base coat
`both are prepared as a solution of vinylidene fluoride in the
`15 acrylic resin. In one experimental test of a finished car body
`panel, a 60° gloss level of greater than about 75 gloss units
`and a DOI approaching about 90 units were achieved.
`Different forms of the invention are disclosed herein. One
`embodiment comprises a thermoformable laminate having a
`20 paint coat with properties capable of use in forming an
`exterior automotive finish on a plastic exterior car body
`panel. A further embodiment of the invention provides a
`process for applying a paint coat to an exterior body panel
`of a motor vehicle so that the paint coat in its finished form
`25 has the durability, gloss and other appearance properties
`necessary for exterior automotive use. Another embodiment
`of the invention comprises a pressure-sensitive adhesive(cid:173)
`backed paint-coated laminate capable of use in automotive
`paint coat repair.
`Thus, the present invention provides a process and articles
`of manufacture in which a laminated exterior paint coat
`ultimately forms an exterior finish on a highly contoured
`surface of a molded plastic article. The paint coat has a
`sufficient combination of elongation and resistance to
`35 deglossing to withstand thermoforming without disrupting
`the high gloss surface originally present, while retaining the
`durability and appearance properties sufficient to be useful
`as an exterior paint coat for a plastic car body panel.
`These and other aspects of the invention will be more
`40 fully understood by referring to the following detailed
`description and the accompanying drawings.
`DRAWINGS
`FIG. 1 is a semi-schematic perspective view illustrating
`an automobile which may have one or more of its exterior
`body members or panels made from a molded plastic
`substrate having a paint coat produced according to prin(cid:173)
`ciples of this invention.
`FIG. 2 is a front elevation view illustrating a rear window
`panel section of a motor vehicle in which an exterior paint
`coat is formed on the surface of the window panel according
`to principles of this invention.
`FIG. 3 is a cross-section taken on line 3-3 of FIG. 2 for
`illustrating the complex three-dimensional shape of the paint
`coat transferred to the exterior surface of the window panel
`FIG. 4 is a schematic cross-sectional view illustrating one
`embodiment of a paint-coated carrier sheet used in the dry
`paint transfer-laminating steps of this invention. Film thick(cid:173)
`nesses are exaggerated in size and not to scale, for simplic(cid:173)
`ity.
`FIG. S is a schematic side elevation view illustrating a
`paint coating step of the process.
`FIG. 6 is a schematic side elevation view illustrating a
`laminating step of the process.
`FIG. 7 is a schematic cross-sectional view illustrating a
`dry composite paint coat transferred to a backing sheet
`
`30
`
`

`

`5,725,712
`
`7
`during the laminating step. Fthn thicknesses are exaggerated
`in size and not to scale, for simplicity.
`FIG. 8 is a schematic view illustrating a thermoforming
`step of the process in which a paint-coated laminate is heated
`¢or to vacuum forming.
`FIG. 9 is a schematic view illustrating another thermo(cid:173)
`forming step in the process.
`FIG. 10 is a schematic cross-sectional view illustrating a
`preliminary step in an injection-cladding step of the process.
`FIG. 11 is a schematic cross-sectional view illustrating a
`substrate material injection-molded behind the thermo(cid:173)
`formed laminate in an injection mold.
`FIG. 12 is schematic cross-sectional view illustrating the
`composite cross-sectional structure of the finished molded
`plastic article having exterior paint coat Film thicknesses
`are exaggerated in size and not to scale, for simplicity.
`FIG. 13 is a graph illustrating a general relationship
`between surface gloss and the relative amounts of polyvi(cid:173)
`nylidene fluoride and acrylic resin contained in one embodi(cid:173)
`ment of the paint coat.
`FIG. 14 is a schematic cross-sectional view illustrating
`one embodiment of a laminate having a dry paint film and
`a pressure-sensitive adhesive backing for use in automotive
`paint coat repair, according to ?"inciples of this invention. 25
`
`8
`contoured exterior surface to which the paint coat can be
`transferred. Referring to the rear window molding 22 in
`FIGS. 2 and 3, the molding has a large oblong-shaped
`window opening 28 with a wide border 30 having a highly
`s contoured exterior surface extending around the window
`opening. The complexly shaped, multiple contour surface
`includes a curved outer ridge 32 of tapered cross-section
`extending around the periphery of the molding, a longitu(cid:173)
`dinally curved and narrow recessed region 34 extending
`10 inside the outer ridge, and a wide border section 36 of raised
`elevation inside the recessed region 34 extending around the
`entire periphery of the window opening. The wide border
`region 36 is at the same elevation as the surface of a wide
`end member 38 at one of the window opening. An inside
`15 edge 40 of the wide border section 36 has a tapered
`cross-sectional thickness and exten