WO2005108512A1

WO2005108512A1 - In-mold coating with improved adhesion

Info

Publication number: WO2005108512A1
Application number: PCT/US2005/014684
Authority: WO
Inventors: Douglas Mcbain
Original assignee: Omnova Solutions Inc.
Priority date: 2004-04-30
Filing date: 2005-04-29
Publication date: 2005-11-17

Abstract

A thermosetting coating for a molded workpiece is disclosed. The coating is made from the reaction product of hydroxypropyl methacrylate, an alpha-alkyl or aryl substituted vinyl acetate, a vinyl substituted aromatic, polyvinyl acetate, and bisphenol A epoxy diacrylate. The coating has an improved adhesion to plastic substrates, including traditionally hard to adhere to substrates such as polyolefins. This provides a coated product with an improved finish layer.

Description

IN-MOLD COATING WITH IMPROVED ADHESION

BACKGROUND The present exemplary embodiment relates to in-mold coatings for substrates having improved adhesion thereto. It finds particular application in conjunction with the coating of compression molded fiber-reinforced plastic substrates, and will be described with particular reference thereto. However, it also is amenable to other like applications, such as the coating of injection molded substrates. Molded plastic materials are used in a variety of applications, such as the transportation, automotive, marine, recreation, construction, office products, and lawn and garden equipment manufacturing industries. In many instances, however, molded plastic work pieces may need to be coated to facilitate paint adhesion, or to satisfy other surface property requirements, such as durability and weather resistance. Because of the inherent low surface energy of plastics, painting or coating often is difficult. Moreover, in view of the variation among the surface properties of individual plastics and the coating compositions to be applied, a method that works with one specific material may not work with another. Hence, a variety of methods have been developed to achieve adhesion of coatings to the surface of molded plastic materials. One common method is to micro-etch the surface of the plastic to generate micro-roughness that will provide adhesion-anchoring sites for the paint or other top and primer coatings. Etching may be done by solvents, which may be incorporated in the paint or coating being applied. Different solvents etch plastic materials at different rates. Both over-etching and under-etching must be avoided. Insufficient etching does not provide proper adhesion, while excessive etching can damage the material. Excessive etching, exposing the coating to bleeding from the plastic, or exposing the plastic to attack by the solvent may warp the parts. If the plastic parts have areas that are highly stressed by the molding process, use of etching solvents can form visible cracks in these areas. The surface of a molded part also can be prepared for painting or coating through de-glazing. When molded, some plastics form a highly crosslinked (glazed) skin which is resistant to solvent etching. Tumbling with a moderately abrasive media, or blasting with a mildly aggressive grit material, may de-glaze the molded surface sufficiently to allow satisfactory adhesion of the paint or coating. Etching or de-glazing may not be desirable or, in some instances, not effective, depending on the particular material surface involved.^' Other methods to prepare a plastic surface utilize a chemical reaction to create polar groups. These methods include coating with an adhesion promoter or subjecting the plastic work piece to flame or plasma treatment. Low polarity plastics also can be oxidatively surface treated using photosensitizers, followed by exposure to ultraviolet light, which breaks bonds in the photosensitizer molecules to form free radicals, an extremely reactive species that combines with ambient oxygen. Oxygen free radicals, in turn, react with the plastic to produce polar groups on the part's surface. Historically, molded plastic work pieces were removed from the mold in which they were formed before application of a coating by a process such as surface treatment, primer coating, top coating, painting, etc. These, methods thus required an additional step - treating the surface of the pre-formed work piece prior to applying a paint or coating - to achieve a finished surface on a work piece. The increased cost and complexity of additional steps made desirable methods by which a thermoset coating could be applied to a plastic work piece in the mold, resulting in a coated work piece the surface of which would be finished and suitable for use as is in an end use application, or which would require less surface preparation treatment. Application of an in-mold coating (IMC) can provide generally smooth surfaces, improve durability and other surface properties, and reduce or eliminate substrate porosity. A number of IMC methods have been employed for applying primer coatings in compression molding methods or injection molding methods, employing molding materials of thermosetting resins, such as SMC (sheet molding compound) and BMC (bulk molding compound); see, e.g., U.S. Pat. Nos. 4,076,788; 4,081 ,578; 4,331 ,735; 4,366,109; and 4,668,460. A conductive, thermoset IMC for molded fiber reinforced thermoplastic (FRP) parts, the binder of which comprises at least one polymerizabie epoxy-based oligo er having at least two acrylate groups and at least one copolymerizable ethylenically unsaturated monomer, can provide good flow and coverage during molding, good adhesion, uniform color, good surface quality, and good paintability; see, e.g., U.S. Pat. No. 5,614,581. Still other in-mold coatings include free-radical peroxide-initiated thermosetting compositions comprising an epoxy-based oligomer having at least two acrylate end groups and a hydroxyl- or amide-containing monomer; see, e.g., U.S. Pat. Nos. 5,391 ,399; 5,359,002; and 5,084,353. IMC compositions, which have appearance or paint-like properties, also are known. Appearance IMC compositions are desirable because they eliminate the additional step, time and cost of applying paint to the surface of a work piece. An example of an appearance IMC is a composition suitable for use on FRP, that comprises a saturated polyester urethane acrylate made from a saturated alipatic polyester intermediate, a saturated aliphatic urethane group and a saturated hydroxyl(alkyl)(meth)acrylate; see U.S. Pat. No. 5,777,053. The use of a diacrylate ester of an alkylene diol, a saturated (cyclo)aliphatic (meth)acrylate, and a vinyl substituted aromatic imparts to the IMC composition paint coating type properties such as hardness, water resistance, low shrinkage, and high gloss. Optionally, and in addition to the aforenoted components, crosslinking agents, such as triallylcyanurate, ethoxylated trimethylolpropane triacrylate, pentaerythritol triacrylate, and the like may be utilized. The components are reacted in the presence of an initiator, such as a peroxide, to chain extend and to form the thermoset saturated polyester urethane acrylate coating resin. The cured resin is a clear IMC composition which, if desired, may be pigmented using various pigments, colorants, etc., to yield a desired end color and opacity. Appearance or paint-like properties of these in-mold coatings are achieved by avoiding various components, especially aromatic compounds such as aromatic polyesters and/or polyether urethane intermediates, aromatic epoxy-based resins and the like. These compositions have been used successfully to form a paint-free FRP end product laminate. While adhesion of the coating to the substrate has been adequate for many applications, it is sometimes necessary to have even stronger adhesion. Thus, a need exists for an IMC suitable for use with compression molded FRP articles that exhibits improved adhesion to the substrate and that also provides superior impact resistance, good adhesion, and excellent weatherability.

BRIEF DESCRIPTION A composition suitable for use as a finish coating on a molded plastic work piece includes the reaction product of hydroxypropyl methacrylate, an alpha-alkyl or aryl substituted vinyl acetate, a vinyl substituted aromatic such as styrene, polyvinyl acetate, and bisphenol A epoxy acrylate. A composite including a substrate with a coating produced from this composition bonded thereto also is.provided. DETAILED DESCRIPTION A composition exhibiting improved adhesion on plastic substrates is provided suitable for providing a coating on a molded work piece. The composition is made from ingredients that include hydroxypropyl methacrylate, an alpha-alkyl or aryl substituted vinyl acetate, a vinyl substituted aromatic such as styrene, polyvinyl acetate, and bisphenol A epoxy acrylate. These components are reacted in the presence of a free radical initiator and optional cure accelerators to form a thermoset resin. The cured resin is suitable for use as an IMC composition. The composition finds applications in the coating of many plastics, including fiber-reinforced thermosets and thermoplastics. A first component of the coating composition is a bisphenol A epoxy diacrylate oligomer, in which the acrylate groups are generally at the terminal portions of the oligomer. As used herein, the term "acrylate" is used to refer to both acrylate as well as methacrylate functional groups unless specified. Thus, in one embodiment, the oligomer may be a bisphenol A epoxy dimethacrylate. The production of bisphenol A epoxy diacrylate oligomers is known, and these materials are commercially available. Such oligomers can be made from the reaction of bisphenol A with an epoxide, typically in the presence of a base. The epoxide generally has from 1 to 15 carbon atoms and desirably is saturated (i.e., has no unsaturated carbon-to-carbon double bonds). A preferred epoxide is epichlorohydrin. Reaction of the bisphenol with excess epoxide will lead to an epoxide terminated oligomer, with the end groups typically referred to as glicidyl ether groups. The number average molecular (M_n) weight of the oligomer can be controlled by suitable adjustment of the epoxide excess and typically varies from 100 to 3000, preferably from about 300 to 1000, with the number of acrylic double bonds preferably being 2 per molecule. The epoxide-terminated oligomer intermediate is reacted with a hydroxyl alkyl (meth)acrylate to form a bisphenol A epoxy diacrylate containing a (meth)acrylate generally at the terminal portions of the polymer chains. The acrylates can generally have a C₂-C₁₀ ester portion, such as ethyl, propyl, n-butyl, ethylhexyl, and the like, with ethyl and propyl being preferred. The bisphenol A epoxy diacrylate can be modified with various functional groups, as known in the art. For ease of processing as well as to achieve a more manageable viscosity, the bisphenol A epoxy diacrylate may be obtained commercially blended with various monomers. Such blends are available from a number of manufacturers, including Sartomer Corporation and UCB Chemicals. An example of such a preferred blend UCB 9125, available from UCB Chemicals, which contains 80 parts by weight (pbw) of bisphenol A epoxy diacrylate resin in 15 pbw styrene monomer and 5 pbw hydroxypropyl methacrylate. A second component is polyvinyl acetate (PVA), which is a thermoplastic resin produced by the polymerization of vinyl acetate in water. Although PVA homopolymer is preferred in certain embodiments, co-monomers such as n-butyl acrylate, 2-ethylhexyl acrylate, ethylene, dibutyl maleate and dibutyl fumarate, etc., can be included In addition, polymerization of vinyl acetate with ethylene also can be used to produce solid vinyl acetate/ethylene copolymers. The reaction can be controlled to produce any degree of replacement of acetate groups in the copolymer. In one embodiment, the PVA polymer will preferably have a M„ of from about 50,000 to 150,000. The amount of PVA in the composition is generally from about 2 to about 25 pbw, desirably from about 5 to about 20 pbw, and preferably from about 10 to about 15 pbw per 100 total pbw of bisphenol A epoxy acrylate. As with the bisphenol A epoxy diacrylate, the PVA may be added as a blend in various monomers to improve handling. A preferred PVA component is a 40% by weight blend of PVA in styrene monomer. A third component utilized in the present invention is hydroxypropyl methacrylate. The amount of the hydroxypropyl methacrylate is generally from about 2 to about 25 pbw, desirably from about 5 to about 20 pbw, and preferably from about 10 to about 15 pbw per 100 total pbw of bisphenol A epoxy diacrylate. This amount is utilized in addition to any hydroxyalkyl methacrylates that may be blended with the bisphenol A epoxy diacrylate oligomer, as described above. A fourth component is one or more vinyl-substituted aromatics containing a total of from 8 to 12 carbon atoms such as styrene, α-methyl styrene, vinyl toluene, t- butyl styrene, and the like, with styrene being preferred. The amount of the vinyl substituted aromatic is generally from about 10 to about 100 pbw, desirably from about 20 to about 80 pbw, and preferably from about 30 to about 50 pbw per 100 total pbw of the bisphenol A epoxy diacrylate. This amount is utilized in addition to any styrene monomer that may be blended with the bisphenol A epoxy diacrylate oligomer and the PVA, as described above. A fifth component is an α-alkyl or aryl-substituted vinyl acetate, wherein the alkyl group can contain from 1 to 10 carbon atoms, such as methyl, ethyl, butyl, etc. A preferred substituted vinyl acetate is vinyl neodecanoate. This may include mixed isomers of the same. The amount of the substituted vinyl acetate is generally from about 10 to about 100 pbw, desirably from about 20 to about 80 pbw, and preferably from about 30 to about 50 pbw per 100 total pbw of the bisphenol A epoxy diacrylate. The above five components generally form the resin of the IMC composition.

The coating composition can be colored by utilizing a pigment, a colorant, etc., in a desired or effective amount to yield a desired color, tint, hue, or opacity. Pigments and pigment dispersions are well known to the art and include, for example, titanium dioxide, carbon black, phthalocyanine blue, phthalocyanine red, chromium and ferric oxides, and the like. The IMC composition also can contain conventional additives, and fillers, etc., in conventional amounts. Thus, various cure inhibitors such as benzoquinone, hydroquinone, methoxyhydroquinone, p-t-butylcatechol, and the like, can be utilized. Various light stabilizers can be utilized such as, for example, the various hindered amines, substituted benzophenones, and substituted benztriazoles, and the like. Lubricants and mold release agents may also be utilized with specific examples including various metal stearates, such as zinc stearate or calcium stearate or phosphonic acid esters. Reinforcing fillers such as talc or carbon black can be utilized. Talc also can promote adhesion of the IMC composition to FRP substrates. Another potential additive is a hardener and thixotrope such as silica. A commercial mold release agent may also be used in the composition. Suitable mold release agents include those that are colorless upon curing of the composition. Stability and dispersion modifiers may also be used, such as Disperse-Ayd™ modified alkyds (Elementis Specialties, Inc.; Hightstown, New Jersey). Preferably included in the composition is a cure accelerator such as, for example, zinc or cobalt ester octoate. These accelerators are conventionally acquired in solutions in mineral oil. Preferred preparations of these accelerators include 12-18% by weight solutions. The amount of the accelerators is generally from about 0.1 to about 4.0 pbw desirably from about 0.3 to about 2.0 pbw, and preferably from about 0.5 to about 1.5 pbw per 100 total pbw of the bisphenol A epoxy diacrylate. The bisphenol A epoxy diacrylate and the other curing monomers or components preferably are chain extended through a free radical initiated process. The bisphenol A epoxy diacrylate may be photocured (UV cured) or cured by an electron beam process. Such processes are known in the art and may be conducted with the use of an appropriate initiator molecule. Alternatively, and preferably, the present embodiments contemplate the heat initiated curing of the coating components through the use of peroxide initiators, or any other initiator or chain extending component capable of. generating free radicals, such as an azo-initiator. Examples of such suitable peroxide free radical initiators include tertiary butyl perbenzoate, t-butyl peroctoate in diallyl phthalate, diacetyl peroxide in dimethyl phthalate, dibenzoyl peroxide, di(p-chlorobenzoyl) peroxide in dibutyl phthalate, di(2,4-dichlorobenzoyl) peroxide in dibutyl phthalate dilauroyl peroxide, methyl ethyl ketone peroxide, cyclohexanone peroxide in dibutyl phthalate, 3,5-dihydroxy-3,4-dimethyl-1 ,2-dioxacyclopentane, t-butylperoxy(2-ethyl hexanoate), caprylyl peroxide, 2,5-dimethyl-2,5-di(benzoyl peroxy) hexane, 1-hydroxy cyclohexyl hydroperoxide-1 , t-butyl peroxy (2-ethyl butyrate), 2,5-dimethyl-2,5-bis(t-butyl peroxy) hexane, cumylhydroperoxide, diacetyl peroxide, t-butyl hydroperoxide, ditertiary butyl peroxide, 3, 5-dihydroxy-3,5-dimethyl-1 ,2-oxacyclopentane, 1 ,1-bis(t-butylperoxy)- 3,3,5-trimethyl cyclohexane and the like, and mixtures thereof. Using mixtures of initiators to take advantage of their different decomposition rates and times at different temperatures, etc., sometimes can be desirable. Azo-initiators useful for the non-aqueous application of this invention include: 2,2'-azobis (2,4-dimethylpentanenitrile); 2,2'-azobis (2-methylpropanenitrile); 2,2'- azobis (2-methylbutanenitrile); 1 ,1'-azobis (cyclohexanecarbonitrile); 2,2'-azobis (4- methoxy-2,4-dimethylvaleronitrile); dimethyl-2,2'-azobisisobutyrate; 2- (carbamoylazo)-isobutyronitrile; 2,2'-azobis (2,4,4-trimethyipentane); 2-phenylazo- 2,4-dimethyl-4-methoxyvaleronitrile); and 2,2'-azobis (2-methylpropane). A preferred peroxide initiator is t-butyl peroxybenzoate (TBPB). The peroxide initiator preferably is used in an amount sufficient to overcome the effect of the inhibitor and to cause curing of the ethylenically unsaturated compounds. In general, the peroxide initiator is used in an amount of up to about 5.0% or from about 0.2 to about 4.0, desirably from about 0.3 to about 3.0%, and preferably from about 0.3 to about 2.0% by weight based on the total weight of all of the ethylenically unsaturated components employed in the IMC compositions. The reaction of the bisphenol A epoxy diacrylate with the curing components in the presence of the peroxide initiator is generally at a temperature of from about 80°C (~180°F) to about 160°C (~330°F), and desirably from about 120°C (~250°F) to about 150°C (~300°F). The coating composition of the present invention may be prepared in conventional mixing equipment. Generally, the bisphenol A epoxy diacrylate is mixed with the vinyl substituted aromatic, the PVA, the substituted vinyl acetate, and the hydroxylpropyl methacrylate. After these compounds are mixed, the accelerators, the mold release agent and any of the above-noted fillers and additives such as cure inhibitors, light stabilizers, lubricants, etc., can be added and mixed. Any initiator is added last. When a coating having a specific color is desired, one or more pigments, colorants, etc., can be utilized in suitable amounts. As known to the art, often times various pigments or colorants are added with a carrier, for example, a polyester, so that they can be easily blended. Any conventional or suitable mixing vessel can be utilized, and the various components and additives mixed until the compounds are blended, with or without the application of external heat. When desired, the mixed ingredients are coated onto an injection molded thermoplastic part with the in-mold coating composition heated to a cure temperature. Suitable cure temperatures may generally range from about 80° to about 160°C (180° to about 330°F). Alternatively, the components of the coating composition can be prepared in separate batches to prolong the shelf-life of the components. In this approach, accelerators can be separated from the peroxide or other cure initiator. This method of preparation includes creating a masterbatch comprising the hydroxypropyl methacrylate (HPMA), the vinyl substituted aromatic, the PVA (e.g. in the form of the PVA/styrene monomer blend), the substituted vinyl acetate, and the bisphenol A epoxy diacrylate (e.g., in the form of the commercial oligomer/monomer blend). The masterbatch may then be divided into at least A and B components. The accelerators can be added to the A component while the initiator and the mold release agent can be added to the B component. The components then an be added together into the mold at the desired time. The IMC compositions are generally flexible and can be utilized on a variety of molded materials, including FRP or non-fiber reinforced plastic substrates. As used herein, the term "plastic" is meant to refer to both cured and uncured plastics, including thermosets and thermoplatics, unless otherwise specified. Injection molding, compression molding, transfer molding, or other molding apparatus or machines can be used for the in-mold coating. Suitable molding apparatus and methods may be found in U.S. Pat. No. 4,081,578, the relevant disclosure of which is incorporated herein by reference. The present embodiments find particular utility in the coating of fiber reinforced or non-fiber reinforced compression molded plastic substrates based on thermoset or thermoplastic resins. These include sheet molding compounds (SMC) as well as bulk molding compounds (BMC) or other materials as well as high strength molding compositions (HMC). In addition, it is within the scope of the invention for the coating to be used in the coating of injection molded substrates, including thermoplastics and thermosets. In one embodiment and when present, the amount of glass fiber or other fiber reinforcement in the substrate to be coated can generally range from about 5 to about 75%, desirably from about 25 to 60%, and preferably from about 35 to 55% by weight. The glass fiber reinforced thermoset plastic substrate can be rigid or semirigid. In lieu of glass fibers, other conventional fibers can also be utilized either separately, or in combination. Examples include carbon fibers, boron fibers, graphite fibers, nylon fibers, and the like. Molding resins that can be used to make articles capable of being coated include, but are not limited to, polyethylene terephthalate, polystyrene, polybutylene terephthalate and alloys, polypropylene, polyurethane, polymethyl methacrylate, acrylonitrile/butadiene/styrene interpolymer, polyvinyl chloride, polyesters, polycarbonates, polypropylene/polystyrene and alloys, polyethylene, nylons, polyacetal, polyolefins, styrene/acrylonitrile, silicones, cellulosics, polycarbonate alloys as well as alloys of such molding resins. Preferred resins include polyesters or vinyl esters resins. As used herein, the term "polyolefin" is intended to be expansive and non- limiting, i.e., it is intended to encompass (but not be limited to) polyolefin homopolymers, copolymers including copolymers of two or more olefin monomers (including block, alternating, and random configurations), blends of two or more polyolefin homopolymers or copolymers, functionalized or substituted polymers containing monomer or polymer side units grafted onto an olefinic polymeric backbone, as well as blends of any of the above with each other or other polymers. Suitable uses for coated articles of the present invention include various automotive parts, such as bumpers and fascias, as well as marine and lawn and garden machine parts, and recreation, construction or office products. Although suitable for the coating of substrates produced by any of various known methods, the coating composition finds particular utility in the in-mold coating of compression molded fiber-reinforced thermoset parts. The embodiments will be better understood by reference to the following examples which serve to illustrate, but not to limit the scope of the present invention.

EXAMPLES In-molding coating compositions were formulated as in Table 1. An

Experimental composition was formulated with HPMA, styrene, PVA (in the form of the PVA/styrene monomer blend), vinyl neodecanoate, and bisphenol A epoxy diacrylate (in the form of a commercially available oligomer/monomer blend) blended together using a high shear mixer while a control coating was formulated without the vinyl neodecanoate. The Disperse-Ayd™ 8 modifier, benzoquinone, cobalt octoate, zinc and calcium stearate were weighed into the resin solution prepared above, and again mixed thoroughly to dissolve the organics and to disperse the stearates. The talc and carbon black were then weighed into the container with the organics and stearate, and mixed thoroughly to disperse the solids. All of the mixing occurred without external heating. The free radical generating initiator, in this instance, t-butyl peroxybenzoate, was added in an amount of 1.8 phr to the IMC composition prepared as set forth above, and mixed thoroughly. Panels were prepared by compression molding glass-reinforced unsaturated polyester Class A molding composition, 25 wt% glass-reinforcement and 75 wt% molding composition, at a mold temperature of ~150° C. The substrate cure time was 60 seconds. After substrate cure, the IMC composition was injected into a 43 cm x 58 cm mold, coating the surface of the cured substrate, using apparatus available from EMC2. The IMC cure time was also 60 seconds. Following the combined cycle of 120 seconds of substrate and IMC cure, the mold was opened and the panel removed. Test specimens were cut from the molded panel and tested in triplicate. TABLE 1 Control Experimental Coating Ingredients pbw Weight % pbw Weight % vinyl neodecanoate (mixed isomers) 0 0 24.00 7.63

PVA in styrene (40%) 10.00 3.18 10.00 3.18 styrene 85.00 27.01 70.00 22.24 bisphenol A epoxy diacrylate blend 100.00 31.78 100.00 31.78

HPMA 26.00 8.26 17.00 5.40 benzoquinone 0.20 0.06 0.20 0.06 zinc stearate 1.85 0.59 1.85 0.59 calcium stearate 0.60 0.19 0.60 0.19 cobalt octoate (12% in mineral spirits) 0.15 0.05 0.15 0.05 dispersant 2.00 0.64 2.00 0.64 carbon black 8.90 2.83 8.90 2.83 talc 80.00 25.42 80.00 25.42 TOTALS 314.70 100.00 314.70 100.00

The results of Tape Adhesion testing (GM9071 P) for control and experimental formulations are reported in Table 2, and Cross-Pull testing (ASTM D3163) of adhesively bonded specimens are reported in Table 3. With respect to Table II, the amount of IMC remaining on the substrate (% retention) reflects the strength of the bonding of IMC to substrate. All of the IMC remaining on the substrate after test (100%) is desirable. With respect to Table III, the failure mode reflects the zone of least strength, i.e., most prone to failure. An adhesive failure of IMC to substrate is an undesirable result, while deep fiber tear of the substrate indicates that the interlaminar strength of the IMC to substrate interface is stronger than that of the composite substrate. Bond specimens were prepared by cutting 2.5 cm x 7.6 cm coupons from the coated samples, followed by bonding the IMC face of two coupons with Plio-Grip™ 7773/220 structural adhesive (Ashland Chemical; Dublin, Ohio). The bond thickness was maintained at .0.8 mm by glass beads of that diameter mixed into the adhesive during application. The bond specimens were cured at room temperature per the manufacturer's recommendations. Table 2: Tape Adhesion - % Retention (GM9071 P)

Table 3: Cross-Peel Test, Failure Mode (ASTM D3163)

Claims

CLAIMSThat which is claimed is:

1. A composition suitable for use as a finish coating on a molded plastic work piece, said composition comprising the reaction product of hydroxypropyl methacrylate, an alpha-alkyl or aryl substituted vinyl acetate, a vinyl substituted aromatic, polyvinyl acetate, and bisphenol A epoxy acrylate.

2. The composition of claim 1 wherein said vinyl substituted aromatic is styrene.

3. The composition of any of claims 1 and 2 wherein said composition comprises from 2 to 25 parts of said polyvinyl acetate, from 5 to 20 parts of said hydroxyl- propyl methacrylate, from 10 to 100 parts of said vinyl substituted aromatic, and from 10 to 100 parts of said alpha-alkyl or aryl vinyl acetate, wherein said parts are parts by weight based upon 100 parts by weight of said bisphenol A epoxy acrylate.

4. The composition of any of claims 1 to 3 wherein said polyvinyl acetate has a number average molecular weight of from 50,000 to 150,000.

5. The composition of any of claims 1 to 4 wherein said alpha-alkyl or aryl substituted vinyl acetate comprises vinyl neodecanoate.

6. The composition of any of claims 1 to 4 wherein the alkyl group of said alpha- alkyl or aryl substituted vinyl acetate contains 1 to 10 carbon atoms.

7. The composition of any of claims 1 to 6 further comprising one or more additional additives selected from light stabilizers, lubricants, fillers, cure inhibitors, and colorants.

8. The composition of any of claims 1 to 7 wherein said reaction product is produced via a curing reaction initiated through the use of a peroxide initiator.

9. A composite including a molded plastic substrate and, bonded thereto, the coating composition of any of claims 1 to 8.