LUBRICANT FOR THERMOPLASTIC RESIN AND THERMOPLASTIC RESIN COMPOSITION COMPRISING SAID LUBRICANT

摘要

A lubricant for a thermoplastic resin, which is a three-stage polymer obtained by (A) polymerizing 80-100 w.t.% of methyl methacrylate and 0-20 w.t.% of other copolymerizable monomer so that the reduced viscosity eta sp/C of the obtained polymer is not higher than 2 dl/g, (B) polymerizing 30-70 weight parts of a monomer mixture composed of 20-80 w.t.% of an acrylic acid ester and 80-20 w.t.% of styrene or a substituted styrene in the presence of 10-60 weight parts of the polymer obtained at stage (A), so that the reduced viscosity eta sp/C of the copolymer obtained by polymerizing 5 to 30 wieght parts of a monomer or monomer mixture composed of 50-100 w.t.% of a methacrylic acid ester and 0-50 w.t.% of other copolymerizable monomer in the presence of the two-stage polymer formed through stages (A) and (B), is that the total amount of the components used at staged (A), (B) and (C) is 100 weight parts and the reduced viscosity eta sp/C of the polymer obtained by polymerizing the monomer or monomer mixture in the absence of the two-stage polymer formed through stages (A) and (B) is not higher than 1.5 dl/g.