Patent ID: 6995197

Claim:
A thermoplastic resin composition comprising: (A) 5 to 40% by weight of a graft copolymer, and (B) 95 to 60% by weight of an aromatic vinyl polymer obtained by polymerization of (b1) 40 to 80 parts by weight of an aromatic vinyl monomer, (b2) 60 to 20 parts by weight of a methacrylic ester and (b3) 0 to 20 parts by weight of other vinyl monomer copolymerizable therewith (the total of (b1), (b2) and (b3) being 100 parts by weight), wherein said graft copolymer is obtained by: preparing a latex of layered diene rubber particles having an average particle size of 500 to 3,000 angstroms and having a layer (i) and a layer (ii) and comprising (a1) at least 50% by weight of a conjugated diene monomer, (a2) a vinyl monomer copolymerizable with said conjugated diene monomer, (a3) 0 to 3% by weight of a crosslinking monomer and (a4) 0 to 3% by weight of a chain transfer agent by subjecting said monomers to multi-stage polymerization so as to form said layer (i) and said layer (ii) in separate stages, wherein said layer (i) comprises said copolymerizable vinyl monomer (a2), and said layer (ii) comprises said conjugated diene monomer (a1) alone or a higher content of said diene monomer than the content of said diene monomer in layer (i), adding to 100 parts by weight (dry basis) of said latex of layered diene rubber particles having an average particle size of 500 to 3,000 angstroms 0.1 to 15 parts by weight (dry basis) of an acid group-containing copolymer latex prepared by polymerization of a monomer mixture comprising 5 to 25% by weight of at least one unsaturated acid selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid and crotonic acid and 95 to 75% by weight of a monomer copolymerizable with said unsaturated acid (the total of the unsaturated acid and the monomer being 100% by weight), thereby agglomerating said rubber particles to give a latex of agglomerated diene rubber particles having an average particle size of 3,500 to 20,000 angstroms, and polymerizing 15 to 60 parts by weight of a vinyl monomer in the presence of 85 to 40 parts by weight (dry basis) of said latex of agglomerated diene rubber particles (the total of said vinyl monomer and said diene rubber particles being 100 parts by weight).