Abstract: An acrylic copolymer vulcanizate, which is a sulfur-vulcanized product of an acrylic copolymer, the acrylic copolymer being obtained by the radical polymerization of a monomeric mixture consisting essentially of 100 parts by weight of at least one acrylic acid ester of an aliphatic alcohol containing 1 to 8 carbon atoms and about 1 to about 15 parts by weight of a 5-substituted-2-norbornene of the general formula ##STR1## wherein R represents .dbd.CH--CH.sub.2).sub. x CH.sub.3, in which x is 0 to 4, or --CH.dbd.CH.sub.2, in the presence of about 0.05 to about 3.0 parts by weight, per 100 parts by weight of the monomeric mixture, of a sulfur vulcanization accelerator which does not cause degradative chain transfer.

Abstract: An acrylic copolymer composition capable of being vulcanized with sulfur comprising the radical polymerization product of (1) a monomer mixture comprising an acrylic acid ester and ethylidene norbornene, (2) a monomer mixture comprising an acrylic acid ester, ethylidene norbornene and acrylonitrile, (3) a monomer mixture comprising an acrylic acid ester and vinyl norbornene, or (4) a monomer mixture comprising an acrylic acid ester, vinyl norbornene and at least one unsaturated compound selected from the group consisting of monovinyl compounds, monovinylidene compounds and monovinylene compounds.