Polysiloxane graft copolymers, flexible coating compositions comprising same and branched polysiloxane macromers for preparing same.

摘要

Hydroxy functional polysiloxane graft copolymers are provided. The copolymer is crosslinkable by hydroxy-reactive crosslinking agent and, in particular, is suitable for use in thermosetting coating compositions adapted to form a flexible cured coating over a variety of substrates, such as metal and plastic. The copolymer has a number average molecular weight between about 1000 and about 15,000, has a hydroxyl number between about 30 and about 300, and is the reaction product of carbon-carbon double bond-reactive monoethylenically unsaturated monomer with hyroxy functional carbon-carbon double bond-bearing branched polysiloxane macromer. The macromer is the reaction product of (i) epoxy monomer having the formula: <CHEM> with (ii) hydroxy functional polysiloxane reactant containing 0-10 urethane linkages per molecule.