Unsaturated polyester resin compositions containing compatible polysiloxane compounds

摘要

A sheet molding composition is disclosed which includes a four component resinous system which comprises (a) an unsaturated polyester comprising a polycondensation product of one or more dihydric alcohols and one or more ethylenically unsaturated polycarboxylic acids; (b) one or more low-profile additives which are thermoplastic polymers which cause phase separation and porosity during the curing reaction; (c) one or more olefinically unsaturated monomers which copolymerize with the unsaturated polyester; and, (d) one or more compatible components comprising at least one polysiloxane polyalkylene copolymer. The compatible components are compatible with the reacted unsaturated polyester and monomer during cure and impart improved surface characteristics when added to low-profile resin systems.