| 摘要 |
PROBLEM TO BE SOLVED: To provide an impact-resistant styrene resin composition giving an injection-molded article having high rigidity and excellent plane impact strength even at a part near the gate of a mold. SOLUTION: The objective impact-resistant styrene resin composition is composed of (A) a styrene resin modified with a polybutadiene rubber and (B) a styrene-butadiene block copolymer and satisfies the following conditions (1) to (7). (1) The component A is a polybutadiene rubber having a 1,2-vinyl-type double bond content of 10-20 mol%; , (2) the number-average particle diameter (Dn) of the polybutadiene particles in the component A is 0.4-0.7μm, (3) the styrene block content of the component B is 35-45 wt.%, (4) the weight-average molecular weight of the component B is 70,000-120,000, (5) the weight-average molecular weight of the polystyrene resin in the composition is 140,000-250,000, (6) the total amount of the polybutadiene rubber derived from the component A and the butadiene block derived from the component B is 7-12 wt.% and (7) the weight ratio of the components described in the item (6) is 35:65 to 65:35.
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