Composite coatings having improved UV and paint stripping resistivity and methods for making same

A co-cured polyurethane-coated epoxy-based composite material stack consisting of:

• a co-cured epoxy-based composite substrate, said co-cured epoxy-based composite substrate comprising a co-cured epoxy-based composite substrate outer surface;
• a co-cured epoxy-based adhesive surfacing material layer disposed on the co-cured epoxy-based composite substrate outer surface, said co-cured epoxy-based adhesive surfacing material layer co-cured with the co-cured epoxy-based composite substrate to form a co-cured miscible region with the co-cured epoxy-based composite substrate, said co-cured miscible region comprising an amount of epoxy-based material from the co-cured epoxy-based composite substrate and an amount of epoxy-based material from the co-cured epoxy-based adhesive surfacing material layer;
• a single co-cured polyurethane-based coating material film layer co-cured with the co-cured epoxy-based adhesive surfacing material layer and the co-cured epoxy-based composite substrate, said single co-cured polyurethane-based coating material film layer in direct contact with the co-cured miscible region said co-cured polyurethane-coated epoxy-based coating material stack comprising an ultraviolet and visible transmittance value of 0% for wavelengths ranging from about 200 nm to about 800 nm when the single co-cured polyurethane-based coating material film layer comprises an average layer thickness ranging from about 2 mils to about 3 mils, said single co-cured polyurethane-based coating material film layer comprising a Tg ranging from about 0° F. to about 200° F.;
• wherein said co-cured epoxy-based adhesive surfacing material layer is configured to begin curing at about 150° F., and at a curing temperature lower than a curing temperature of the co-curable epoxy-based composite substrate;
• wherein said co-cured epoxy-based composite substrate, said co-cured epoxy-based adhesive surfacing material layer, and said single co-cured polyurethane-based coating material film layer are co-cured at a co-curing temperature ranging from about 250° F. to about 350° F.;
• wherein the single co-cured polyurethane-based coating material film layer alone is configured to impart UV protection to the co-cured epoxy-based composite substrate;
• wherein the co-cured miscible region impedes epoxy-based material from the co-cured epoxy-based composite substrate from migrating into the single co-cured polyurethane-coated epoxy-based composite material film layer;
• and
• wherein the co-cured polyurethane-coated epoxy-based composite material stack comprises an amount of an epoxy-based material co-cured at a co-curing temperature ranging from about 250° F. to about 400° F., and a Tg ranging from about 300° F. to about 450° F., and a gel time ranging from about 5 minutes to about 20 minutes when held at a co-curing temperature ranging from about 240° F. to about 260° F.

A method for improving UV radiation resistance of a co-cured polyurethane-coated epoxy-based composite material stack, the method consisting of:

• applying a co-curable epoxy-based adhesive surfacing material film layer to an outer surface of a co-curable epoxy-based composite substrate, said co-curable epoxy-based adhesive surfacing material film layer configured to begin curing at a curing temperature of about 150° F. and at a temperature lower than a curing temperature of the co-curable epoxy-based composite substrate;
• applying a single co-curable polyurethane-based coating material film layer comprising a Tg ranging from about 0° F. to about 200° F. to the co-curable epoxy-based adhesive surfacing material film layer to form a co-curable polyurethane-coated epoxy-based composite material stack, said single co-curable polyurethane-based coating material film layer in direct contact with the co-curable epoxy-based adhesive surfacing material film layer;
• beginning curing of the co-curable epoxy-based adhesive surfacing material film layer at a curing temperature of about 150° F. and at a curing temperature lower than a co-curing temperature of the co-curable epoxy-based composite substrate;
• co-curing the co-curable polyurethane-coated epoxy-based composite material stack at a predetermined co-curing regimen that comprises co-curing the co-curable polyurethane-coated epoxy-based composite material stack at a co-curing temperature ranging from about 250° F. to about 400° F. to form the co-cured polyurethane-coated epoxy-based composite material stack comprising a co-cured epoxy-based composite substrate, a co-cured epoxy-based surfacing material film layer, and a single co-cured polyurethane-based coating material film layer;
• forming a co-cured miscible layer comprising an amount of epoxy-based material from the co-cured epoxy-based composite substrate and an amount of epoxy-based material from the co-curable epoxy-based adhesive surfacing material film layer, said co-cured miscible layer configured to impede migration of epoxy-based material from the co-cured epoxy-based composite substrate to an outer surface of the co-cured polyurethane-coated epoxy-based composite material stack;
• imparting UV protection to the co-cured polyurethane-coated epoxy-based composite material stack in the single co-cured polyurethane-based coating material film layer;
• and
• wherein the co-cured polyurethane-coated epoxy-based composite material stack has an ultraviolet and visible transmittance value of 0% for wavelengths ranging from about 200 nm to about 800 nm when the single co-curable polyurethane-based coating material film layer comprises an average layer thickness ranging from about 2 mils to about 3 mils.