Patent ID: 6232358
Filing Date: 2001-05-15
Classification: C08F,C08J,C08L

Abstract:
An expandable rubber-modified styrene resin composition comprising 85 to 99% by weight of a rubber-modified styrene resin containing a rubber particle of a diene polymer which is a homopolymer of butadiene or isoprene, 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.degree. C. or lower, wherein:the weight-average molecular weight of said continuous phase of the styrene 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.degree. C. is 12 to 25, wherein graft ratio is defined as (Gel content--Diene polymer content).times.100/(Diene polymer content), and wherein gel content is the value in weight percent of a dry gel to the rubber-modified styrene resin.