Patent ID: 7589142

Claim:
A thermoplastic resin composition comprising the following components: (A) from 20 to 79.5 parts by weight of a polyamide resin; (B) from 20 to 79.5 parts by weight of a graft polymer, said graft polymer being obtained by, (a) in the presence of from 40 to 80 wt % of a rubber-like polymer having a swell index of 10 to 80 and a weight average particle diameter of 100 to 600 nm, (b) graft-polymerizing from 20 to 60 wt % of a monomer mixture comprising: (i) from 50 to 90 wt % of an aromatic vinyl-based monomer, (ii) from 10 to 50 wt % of a vinyl cyanide-based monomer, and (iii) from 0 to 30 wt % of another vinyl monomer copolymerizable with those monomers, in which the acetone-soluble moiety of the graft polymer has a number average molecular weight of 20,000 to 100,000; (C) from 0.5 to 60 parts by weight of an unsaturated carboxylic acid-modified polymer, said unsaturated carboxylic acid-modified polymer being obtained by copolymerizing from 0.05 to 20 wt % of an unsaturated carboxylic acid monomer, from 50 to 89.95 wt % of an aromatic vinyl-based monomer and from 10 to 49.95 wt % of a vinyl cyanide-based monomer, and having a number average molecular weight of 25,000 to 60,000; and (D) from 0 to 50 parts by weight of a copolymer, said the copolymer being obtained by copolymerizing from 50 to 90 wt % of an aromatic vinyl monomer, from 10 to 50 wt % of a vinyl cyanide-based monomer and from 0 to 60 wt % of a maleimide-based monomer and/or unsaturated carboxylic acid ester-based monomer; with the proviso that the total amount of the components (A) to (D) is 100 parts by weight.