Patent ID: 8647745

Claim:
A dual-coat powder coating system comprising: (I) an epoxy thermoset primer comprising: (i) an epoxy resin having an EEW of about 860 to about 930; (ii) a polyhydroxyl functional phenolic curing agent having a hydroxyl equivalent weight of about 200 to about 500; and (iii) a filler material, wherein said epoxy thermoset primer is substantially zinc-free, and (II) an overlying epoxy-polyester thermoset topcoat comprising: (i) an epoxy resin having an EEW of about 520 to about 930; (ii) an elastomer-modified epoxy resin having an EEW of about 1000 to about 1600; (iii) a carboxyl functional polyester resin with acid number of about 45 to about 75 mg KOH/g; (iv) a foaming agent; and (v) a reinforcing fiber.