In-mold coating of polymer composite parts for metallization and painting
View Patent ↗The surface of a molded fiber reinforced polymer matrix article is prepared for subsequent metallization and painting by coating the molded article, preferably while it is still in its mold, with a layer of calcium carbonate-filled, but fiber-free polymer. The calcium carbonate-filled coating is then etched to dissolve particles of calcium carbonate from the surface layer to form fiber-free micro-pores in the surface layer. This porous provides an improved base for the deposition of a metal layer for receiving adherent paint layers and preventing “out-gassing” of the composite body during baking of the paint layers.
1. A method of preparing a surface of a molded, fiber reinforced polymer composite article for application of one or more paint layers to said surface when such article is to be subjected to a paint baking operation for at least one of said applied paint layers, said method comprising:
coating said surface of said fiber reinforced article with an overlying co-extensive layer of fiber-free, polymer resin filled with acid soluble filler particles;
dissolving acid soluble filler particles from the surface of said overlying layer to form micro-pores in said layer, said micro-pores being free of fibers of said fiber reinforced polymer composite article; and
forming at least one layer of a metal coating on said micro-pore containing, overlying layer as a barrier coating to out-gassing from said polymer composite article during said paint baking operation.
2. The process as recited in claim 1 in which said acid soluble filler particles are calcium carbonate particles.
3. The method as recited in claim 1 in which said fiber reinforced polymer composite article comprises a molding compound containing unsaturated polyester and polystyrene resins.
4. The method as recited in claim 1 in which said overlying layer comprises a molding compound containing unsaturated polyester and polystyrene resins.
5. The method as recited in claim 1 in which said polymer composite article is formed in a mold defining said surface and said overlying co-extensive layer of fiber-free, polymer resin filled with said filler particles is applied to said surface while said article is in said mold.
6. The method as recited in claim 1 in which said metal barrier coating comprises a metal selected from the group consisting of aluminum, iron and zinc.
7. The method as recited in claim 1 in which said metal barrier coating is zinc or a zinc based alloy.
8. A method of preparing a surface of a fiber reinforced polymer composite article for application of one or more paint layers to said surface when such article is to be subjected to a paint baking operation for at least one of said applied paint layers, said method comprising:
forming fiber containing polymeric precursor materials in a mold to obtain said article, said mold comprising mold elements movable between open and closed positions;
coating said surface with an overlying co-extensive layer of fiber-free, polymer resin filled with calcium carbonate particles, said coating being performed while said article is in said mold;
dissolving calcium carbonate particles from the surface of said overlying layer to form micro-pores in said layer, said micro-pores being free of fibers of said fiber reinforced polymer composite; and
forming at least one layer of a metal coating on said micro-pore containing, overlying layer as a barrier coating to out-gassing from said polymer composite article during said paint baking operation.
9. The method as recited in claim 8 in which said coating is performed while said mold elements are in their closed position.
10. The method as recited in claim 8 in which said coating is performed while said mold elements are in a position between their open and closed positions.
11. The method as recited in claim 8 in which said fiber reinforced polymer composite article comprises a molding compound containing unsaturated polyester and polystyrene resins.
12. The method as recited in claim 8 in which said overlying layer comprises a molding compound containing unsaturated polyester and polystyrene resins.
13. The method as recited in claim 8 in which said metal barrier coating comprises a metal selected from the group consisting of aluminum, iron and zinc.
14. The method as recited in claim 8 in which said metal barrier coating is zinc or a zinc based alloy.
15. The method as recited in claim 11 in which said overlying layer comprises a molding compound containing unsaturated polyester and polystyrene resins.