Patent ID: 7049369

Claim:
A styrene resin composition comprising a linear polystyrene having a weight average molecular weight of 200,000 to 350,000 and a multibranched polystyrene obtained by copolymerizing a multibranched macromonomer and styrene having a weight average molecular weight of 1,000,000 to 10,000,000, which has a weight average molecular weight of 250,000 to 700,000, and a melt mass-flow rate (MFR) and melt tension (MT) which satisfy formulas (1) and (2) respectively: MFR ( g/ 10 min)≧45×exp(−0.1 ×Mw× 10 −4 ) (1) (wherein, MFR and Mw denote a melt mass-flow rate as measured at 200° C. under a load of 49N in accordance with JIS K7210:99 and a weight average molecular weight respectively for said styrene resin composition), MT ( g )≧0.07 Mw× 10 −4 +1.8 (2) (wherein, MT and Mw denote a melt tension and a weight average molecular weight respectively for said styrene resin composition).