Covalently compatible in-mold coating compositions for use with epoxy

1. A process for forming a molded plastic substrate comprising:

providing a mold;

providing an epoxy matrix resin base comprising an amine component;

providing a gelcoat composition comprising:

a base resin comprising an ethylenically unsaturated matrix; and

a reactive diluent consisting of one or more functional monomers selected from Formula I,

ethoxylated trimethylpropane triacrylate, or trimethylpropane trimethacrylate;

wherein:

R is a 5 to 10 carbon atom containing mono- or dicyclic alkyl or alkenyl ester radical having one or more optional alkyl substituents of 1 to 3 carbon atoms, and

R′ is H or CH 3 ;

applying a layer of the gel coat composition to the mold;

allowing the gel coat composition to partially cure until it is tacky; and

applying the epoxy matrix resin base over the partially-cured gel coat composition,

wherein a Michael addition of the acrylate or methacrylate ester component of Formula I and the amine component of the epoxy matrix results in a plurality of amine-acrylate adducts that in turn react with the epoxy matrix resin base to achieve a covalent bond between the epoxy matrix resin base and the gel coat composition, wherein the gel coat provides mechanical and physical performance comparable to conventional gel coats, thereby forming a molded plastic substrate.

2. The process of claim 1 , wherein at least one functional monomer of the reactive diluent is a methacrylated isobornyl component.

3. The process of claim 1 , wherein the gel coat composition comprises a reactive diluent consisting of at least two different functional monomers of formula I.

4. The process of claim 1 , wherein the amine component comprises an aliphatic amine.

5. The process of claim 1 , wherein at least one functional monomer of the reactive diluent of the gelcoat is isobornyl methacrylate.

6. The process of claim 1 , wherein the base resin of the gelcoat comprises unsaturated polyester.

7. The process of claim 1 , wherein at least one functional monomer of the reactive diluent of the gelcoat is ethoxylated trimethylpropane triacrylate.

8. The process of claim 1 , wherein at least one functional monomer of the reactive diluent of the gelcoat is trimethylpropane trimethacrylate.

9. The process of claim 1 , wherein the reactive diluent of the gelcoat consists of isobornyl methacrylate, ethoxylated trimethylpropane triacrylate, and trimethylpropane trimethacrylate.

10. The process of claim 9 , wherein the base resin of the gelcoat consists of unsaturated polyester and urethane methacrylate oligomer.

11. The process of claim 1 , wherein the gelcoat composition comprises a base resin consisting of unsaturated polyester and urethane methacrylate oligomer; and reactive diluent consisting of isobornyl methacrylate, ethoxylated trimethylpropane triacrylate, and trimethylpropane trimethacrylate.

12. The process of claim 1 , wherein the gelcoat composition consists of a base resin consisting of unsaturated polyester and urethane methacrylate oligomer; a reactive diluent consisting of isobornyl methacrylate, ethoxylated trimethylpropane triacrylate, and trimethylpropane trimethacrylate; a UV stabilizer; a promotion package; a free radical component; a stabilizer package; a thixotropic agent; a filler; a pigment; and an initiator.

13. The process of claim 12 , wherein the gelcoat composition consists of a base resin consisting of unsaturated polyester and urethane methacrylate oligomer; a reactive diluent consisting of isobornyl methacrylate, ethoxylated trimethylpropane triacrylate, and trimethylpropane trimethacrylate; a UV stabilizer; a promotion package; a free radical component consisting of phenothiazine: isobornyl methacrylate; a stabilizer package consisting of hydroquinone: isobornyl methacrylate; a thixotropic agent consisting of fumed silica; a filler consisting of wollastonite clay; a pigment consisting of titanium dioxide white dispersion; and an initiator consisting of methyl ethyl ketone peroxide.

14. A process for forming a molded plastic substrate comprising:

providing a mold;

providing an epoxy matrix resin base comprising an amine component;

providing a gelcoat composition comprising:

a base resin comprising an ethylenically unsaturated matrix; and

a reactive diluent consisting of one or more functional monomers of Formula I,

wherein:

R is a 5 to 10 carbon atom containing mono- or dicyclic alkyl or alkenyl ester radical having one or more optional alkyl substituents of 1 to 3 carbon atoms, and

R′ is H or CH 3 ;

applying a layer of the gel coat composition to the mold;

allowing the gel coat composition to partially cure until it is tacky; and

applying the epoxy matrix resin base over the partially-cured gel coat composition,

wherein a Michael addition of the acrylate or methacrylate ester component of Formula I and the amine component of the epoxy matrix results in a plurality of amine-acrylate adducts that in turn react with the epoxy matrix resin base to achieve a covalent bond between the epoxy matrix resin base and the gel coat composition, wherein the gel coat provides mechanical and physical performance comparable to conventional gel coats, thereby forming a molded plastic substrate.

15. The process of claim 14 , wherein the base resin of the gelcoat comprises unsaturated polyester.

16. The process of claim 14 , wherein at least one functional monomer of the reactive diluent is a methacrylated isobornyl component.

17. The process of claim 14 , wherein the gel coat composition comprises a reactive diluent consisting of at least two different functional monomers of formula I.

18. The process of claim 14 , wherein the amine component comprises an aliphatic amine.

19. The process of claim 14 , wherein at least one functional monomer of the reactive diluent of the gelcoat is isobornyl methacrylate.