Low-shrink thermosetting polyesters

摘要

This invention pertains to low-shrink polyester molding resin mixtures primarily based on a certain low-shrink thermoplastic additive produced by synthesizing the vinyl copolymer thermoplastic additive in a hydroxyl terminated polymeric diluent. The resulting vinyl copolymer is dispersed in the hydroxyl containing polymeric diluent which can be post reacted with isocyanate material to produce a polyurethane-vinyl copolymer thermoplastic additive. This thermoplastic additive can be added directly to the thermosetting polyester polymer and monomer mixture to provide a low-shrink molding resin system.