Rubber-modified nylon composition

Claim 1

A polymer blend comprising: (A) a graft rubber composition comprising from 5 to 80 weight percent of a substrate rubber having a glass transition temperature below 0° C. and from 95 to 20 weight percent of monomers comprising per 100 parts by weight of the monomers from 20 to 75 parts by weight of a vinyl aromatic monomer and from 80 to 25 parts by weight of polar monomer selected from the group consisting of C 1 to C 4 alkyl (meth)-acrylate and (meth)-acrylonitrile, said monomers having been polymerized in the presence of and grafted on to the substrate rubber; (B) a polyamide; (C) an acid-containing ethylene/alkyl acrylate copolymer rubber having a glass transition temperature below 0° C., said rubber consisting of ethylene, C 1 to C 4 alkyl acrylate and 0.5 to 25 mole percent of an interpolymerized acid-containing monomer selected from (meth)-acrylic acid, a dicarboxylic acid or annhydride or a C 1 to C 12 monoalkyl ester of a dicarboxylic acid; and (D) an effective amount of an acid-containing terpolymer to improve the impact resistance of the polymer blend comprising components (A), (B) and (C), said acid-containing terpolymer having a glass transition temperature above 0° C. and consisting of a vinyl aromatic monomer, a polar monomer selected from the group consisting of C 1 to C 4 alkyl (meth)arcylate and (meth) acrylonitrile and from about 0.05 to about 50 mole percent of acid functional comonomer units selected from (meth)acrylic acid, a dicarboxylic acid or anhydride or a C 1 to C 12 monoalkyl ester of a dicarboxylic acid; wherein the weight ratio of component (A) to component (B) is in the range of about 1:9 to about 9:1, wherein the sum of components (A) and (B) is at least about 60 weight percent of the polymer blend and wherein the amount of component (C) is in the range of 1 to 18 weight percent of the polymer blend and the amount of component (D) is in the range of 0.05 to 20 weight percent.