IMPACT STRENGTH MODIFIER AND VINYL CHLORIDE RESIN COMPOSITION HAVING EXCELLENT IMPACT RESISTANCE AND MOLDABILITY AND CONTAINING THE MODIFIER

摘要

PROBLEM TO BE SOLVED: To obtain an impact strength modifier useful for a vinyl chloride resin composition suiting the use required to have high impact strength and stable moldability such as watersupply pipe, sewage line pipe, etc. by including a specific two-stage graft copolymer. SOLUTION: The objective modifier is a two-stage graft copolymer produced by graft-polymerizing (A) 60-99 wt.% of a diene rubber with (B) 1-40 wt.% (the sum of A and B is 100 wt.%) of monomers composed of 50-99.9 wt.% of one or more kinds of acrylic acid esters having a 1-8C alkyl group and 0.1-50 wt.% of other copolymerizable vinyl monomers and graft-polymerizing (C) 70-95 wt.% of the obtained graft copolymer with (D) 5-30 wt.% (the sum of C and D is 100 wt.%) of monomers composed of 50-100 wt.% of one or more kinds of methacrylic acid esters having a 1-4C alkyl group and 50-0 wt.% of other copolymerizable vinyl monomers. The graft copolymer contains <=12 wt.% of component extractable with tetrahydrofuran.