摘要 |
Composition of matter adapted to be foamed into essentially a closed cell structure, preponderance of the cells being less than 500 microns in size and containing a chlorofluoroalkane of 1 to 2 carbon atoms, said composition comprising chlorinated polyvinyl chloride resin, and effective amount of a blowing agent, an effective amount of a nucleating agent, and 5 to 20 parts of a processing aid per 100 parts of said resin, said processing aid has a dilute solution viscosity of greater than 2.5 and is selected from copolymers of styrene and acrylonitrile containing 10 to 40% of acrylonitrile. |