Patent ID: 7396876

Claim:
An impact-resistant thermoplastic resin composition comprising: 5 to 40 parts by weight of a graft copolymer (A) and 95 to 60 parts by weight of a copolymer (B); wherein the copolymer (B) is prepared by polymerizing 75 to 100 percent by weight of a monomer selected from the group consisting of an aromatic vinyl monomer, an alkyl methacrylate monomer, a vinylcyanide monomer, and combinations thereot with 25 to 0 percent by weight of a vinyl monomer copolymerizable therewith, wherein the aromatic vinyl monomer comprises 20 to 90 percent by weight, such that (A) and (B) total 100 parts by weight; and wherein the graft copolymer (A) is prepared by polymerizing 60 to 15 parts by weight of a monomer mixture (GM) in the presence of 40 to 85 parts by weight of agglomerated rubber particles (R2) having a volume average particle diameter of 1,900 to 20,000 Å, such that the agglomerated rubber particles (R2) and the monomer mixture (GM) total 100 parts by weight; wherein the monomer mixture (GM) comprises 80 to 100 percent by weight of a monomer selected from the group consisting of an alkyl methacrylate monomer, an aromatic vinyl monomer, a vinylcyanide monomer, and combinations thereof, and 20 to 0 percent by weight of a vinyl monomer copolymerizable therewith; wherein the agglomerated rubber particles (R2) are prepared through cohesion by adding 0.5 to 6 parts by solid content weight of an acid-group-containing copolymer (S) latex into 100 parts by weight of a diene rubber (R1) having a volume average particle diameter of 1,500 Å or less; wherein the acid-group-containing copolymer (S) latex is prepared by polymerizing a monomer mixture comprising 10 to 20 percent by weight of an unsaturated acid monomer selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, crotonic acid, and combinations thereof, 30 to 60 percent by weight of an aromatic vinyl monomer, 15 to 30 percent by weight of one or a plurality of alkyl acrylate monomers comprising a C 1 to C 12 alkyl, 0 to 15 percent by weight of an alkyl methacrylate monomer comprising a C 1 to C 12 alkyl, and 0 to 20 percent by weight of a vinyl monomer copolymerizable therewith; and wherein the diene rubber (R1) is prepared by polymerizing a monomer mixture comprising 60 to 95 percent by weight of a conjugated diene monomer 40 to 5 percent by weight of an aromatic vinyl monomer, 10 to 0 percent by weight of a vinyl monomer copolymerizable with the conjugated diene monomer, 0 to 3 percent by weight of a cross-linkable monomer, and 0 to 3 percent by weight of a chain transfer agent; and wherein a difference in refractive index between the acid-group-containing copolymer (S) and the graft copolymer (A) is 0.02 or less.