In-mold coating by a multiple step infusion process
View Patent ↗A coating may be incorporated in a molded composite article made via a process in which neither the coating nor the resin contact the mold surface. A multilayer sandwich structure is formed having two outside layers of flexible membranes, typically made of silicon. An interior dissolvable film is disposed between the two outer flexible membranes. A layer of fiber reinforcement is disposed between the dissolvable film and one of the flexible membranes. A coating is distributed between a flexible membrane and the dissolvable film, opposite the side having the reinforcement, wherein the film is only slowly soluble, or insoluble, in the coating. The coating is allowed to at least partially cure and a resin is infused through the reinforcement wherein the dissolvable film rapidly dissolves in the resin. The sandwich structure is formed around a mold and the resin is allowed to cure.
1. A method of making a coated composite article, the method comprising: positioning a dissolvable inner film to at least temporarily isolate a coating resin composition from a molding resin composition,
wherein
the inner film is insoluble or only slowly soluble in the coating resin composition and is rapidly soluble in the molding resin composition,
the coating resin composition comprises a reactive monomer that is not a good solvent for the inner film, and
the molding resin composition comprises at least one reactive solvent selected from monomers which strongly dissolve the inner film.
2. The method of claim 1 , wherein the inner film comprises a styrene polymer or copolymer.
3. The method of claim 2 , wherein the inner film comprises polystyrene.
4. The method of claim 1 , wherein the molding resin composition comprises a molding resin selected from the group consisting of unsaturated polyesters, vinyl esters and acrylic acrylated resins.
5. The method of claim 1 , wherein the reactive monomer is a polar reactive solvent.
6. The method of claim 1 , wherein the reactive monomer comprises an ethoxylated multifunctional acrylate monomer.
7. The method of claim 1 , wherein the coating resin composition comprises a coating resin selected from the group consisting of unsaturated polyester acrylic acrylated resin, vinyl ester and epoxy resin.
8. The method of claim 1 , wherein the reactive solvent is selected from the group consisting of styrene, styrene derivatives and methyl methacrylate.
9. The method of claim 1 , wherein the inner film is positioned such that the coating resin composition is between and in contact with both a mold surface and the inner film.
10. The method of claim 1 , further comprising applying the coating resin composition to a mold surface by spraying, brushing or vacuum infusion.
11. The method of claim 10 , wherein the mold surface is a flexible membrane or a rigid surface.
12. The method of claim 1 , further comprising allowing the coating resin composition to at least partially cure prior to contacting the inner film with the molding resin composition.
13. The method of claim 12 , further comprising
applying the molding resin composition to the inner film; and
allowing the inner film to dissolve in the molding resin composition.
14. The method of claim 13 , further comprising allowing the molding resin composition to cure.