UNSATURATED POLYESTER RESIN COMPOSITION HAVING LOW SHRINKAGE PROPERTY

摘要

PROBLEM TO BE SOLVED: To obtain an unsaturated polyester resin composition capable of providing a molded product having high design property, excellent in low shrinkage property, moldability and color shading preventing property and having both of whiteness and translucent feeling by including a three-dimensional polystyrene and an uncrosslinked polystyrene at a ratio having a definite composition. ;SOLUTION: This polyester resin composition contains (A) an unsaturated polyester resin as an essential thermosetting resin component and contains as (B) a shrinkage reducing agent both of (i) a three-dimensional polystyrene and (ii) an uncrosslinked polystyrene having ≤70,000 (preferably ≥5,000) weight- average molecular weight, and total amount of components (i) and (ii) added is 5-30 pts.wt. and amount of the component (i) added is 1-10 pts.wt. based on 100 pts.wt. polyester resin. The component (i) is a crosslinked polymer having a three-dimensional network structure and obtained by (co)polymerizing styrene monomer only or styrene monomer and a monomer copolymerizable with styrene monomer in the presence of a crosslinking agent. The component (ii) is a homopolymer of styrene.;COPYRIGHT: (C)2000,JPO