Patent ID: 7015282

Claim:
A polyvinyl chloride composition containing a core/shell impact additive, said impact additive comprising: a) 70% to 90% by weight of a crosslinked elastomeric core which is composed: 1) of 20% to less than 100% by weight of a nucleus composed of a copolymer (I) of an n-alkyl acrylate, the alkyl group having a carbon number ranging from 5 to 12, of a polyfunctional crosslinking agent possessing unsaturated groups in its molecule, at least one of which is a vinyl group and optionally of a polyfunctional grafting agent possessing unsaturated groups in its molecule, at least one of which is an allyl group, and 2) of more than 0 and not more than 80% by weight, of a covering composed of a copolymer (II) of n-alkyl acrylate, the alkyl group of which has a carbon number ranging from 4 to 12, and a grafting agent possessing allyl groups, the said covering containing a molar amount of grafting agent ranging from 0.05% to 2.5%, said grafting agent having only allyl functional groups, all having the same reactivity and, b) 30% to 10% by weight of a shell grafted onto the said core composed of a polymer of an alkyl methacrylate, the alkyl group of which has a carbon number ranging from 1 to 4, or alternatively of a statistical copolymer of an alkyl methacrylate, the alkyl group of which has a carbon number ranging from 1 to 4, and of an alkyl acrylate, the alkyl group of which has a carbon number ranging from 1 to 8, containing a molar amount of alkyl acrylate ranging from 5% to 40%, or alternatively composed of a styrene acrylonitrile copolymer.