Chlorinated polyvinyl chloride resin (CPVC) is blended with a block copolymer of styrene and a diene (SD) or of styrene-diene-styrene (SDS), which block copolymer is referred to as a "pro-modifier" because, by itself, it performs a dual function of processing aid and impact modifier in CPVC. For tailoring...http://www.google.es/patents/US4181644?utm_source=gb-gplus-sharePatente US4181644 - Impact modified polymer composition
