Patent ID: 7879937

Claim:
A molded polymer material obtained from a polymer composition comprising: (A) at least one un-neutralized polymer containing α,β-ethylenically unsaturated carboxylic acid, (B) at least one diene polymer, which is a polybutadiene synthesized with a lanthanide series catalyst and having a cis-1,4 bond content of at least 60%, a 1,2-vinyl bond content of not more than 4%, a Mooney viscosity (ML 1+4 (100° C.)) of 35 to 65, a weight-average molecular weight (Mw) of 450,000 to 850,000, and a weight-average molecular weight (Mw) to number-average molecular weight (Mn) ratio of 5 or less; (C) at least one metal cation source, (D) at least one organic peroxide, and (E) a metal salt of an α,β-ethylenically unsaturated carboxylic acid monomer; wherein the molded polymer material is obtained by: (i) mixing components A and B; (ii) adding component C to the resulting mixture, thereby neutralizing some or all of the carboxyl groups in component A with component C in the presence of component B; (iii) adding component E; and (iv) adding component D and molding and crosslinking under the influence of radicals generated by decomposing component D, wherein component A is an un-neutralized polymer consisting of an α,β-ethylenically unsaturated carboxylic acid.