Expandable rubber-modified styrene resin compositions

摘要

To provide an expandable rubber-modified styrene resin composition that is enabled to obtain a molded foam having a high expansion ratio, an excellent impact resistance and pliability and satisfactory appearance. The expandable rubber-modified styrene resin composition comprises 85 to 99% by weight of a rubber-modified styrene resin containing a rubber particle of a diene polymer dispersed in a continuous phase of a styrene resin and 1 to 15% by weight of a volatile blowing agent whose boiling point is 80° C. or lower, wherein:the weight-average molecular weight of said continuous phase of styrene resin is 150,000 to 300,000;the graft ratio of the styrene resin to the diene polymer is 70 to 135%; and,the swelling index of the gel fraction of said diene polymer in toluene at 25° C. is 12 to 25.