Coating composition containing hydroxy functional epoxy-polyester graft copolymers

摘要

An hydroxy functional epoxy-polyester graft copolymer and solvent-based thermosetting coating composition comprising said copolymer and blocked polyisocyanate crosslinking agent. The coating composition may be formulated as hot sprayable, high solids coating composition suitable for use as chip resistant automotive vehicle primer adapted for use on body panel areas subject to chipping by stones, gravel and other road debris. Alternatively, the composition may be formulated as a high solids composition sprayable with conventional spraying equipment. The hydroxy functional epoxy-polyester graft copolymer is the product of polymerization of certain lactone monomers in the presence of hydroxy functional epoxy amine adduct precursor. The precursor resin is the reaction product of diepoxide with aliphatic diol and, subsequently, with hydroxy functional secondary amine. The polymerization of the lactone monomers is carried out at a temperature between about 50 DEG C. and about 300 DEG C. and the polymerization reaction mixture comprises between about 10 and about 80 weight percent hydroxy functional epoxy amine adduct precursor and between about 90 and about 20 weight percent lactone monomers.