Polyester graft copolymers, flexible coating compositions comprising same and branched polyester macromers for preparing same II

Claim 1

Hydroxy functional polyester graft copolymer suitable for flexible, thermosetting coating compositions over metal and plastic substrates, which copolymer has number average molecular weight between about 1,300 and about 15,000 has a hydroxyl number between about 30 and about 300, and consists of the reaction product of (1) carbon-carbon double bond-reactive monoethylenically unsaturated monomer with (2) hydroxy functional carbon-carbon double bond-bearing branched polyester urethane macromer, said reaction product formed under free radical polymerization reaction conditions, said monomers bearing substantially no functionality which is substantially reactive with hydroxy functionality of said macromer under said reaction conditions and said macromer being the reaction product consisting of: (i) hydroxy functionality polyester urethane having about 1-10 urethane groups per molecule with (ii) silane compound having the general chemical formula: ##STR6## wherein X is an organic group or (--Si--O) n , n being 1-50, and X' is independently (a) an organic group, (b) an organic group comprising hydroxy-reactive functionality, or (c) hydroxy-reactive functionality, at least one X' comprising hydroxy-reactive functionality; said polyester urethane consists of the hydroxyl terminated esterification product of a polyol and a dicarboxylic acid or anhydride thereof and an organic diisocyanate.