GB723456A - Improvements in or relating to a process for producing synthetic rubbery compositions - Google Patents

Abstract

Synthetic rubbery compositions are prepared by mixing a synthetic rubbery polymeric material comprising predominantly linear carbon chains to which are attached from 0.001 to 0.30 chemical equivalents by weight of combined carboxyl ( - COOH) per 100 parts by weight of polymer with an amount of curing agent sufficient to react with at least 1/10 of the carbonyl groups, the curing agent being selected from primary and secondary aliphatic and heterocyclic polyamines and their salts containing at least two amino- or imino-nitrogen groups and heating at from 100 DEG to 450 DEG F. until an elastic condition is produced. The polymeric material may be prepared by any of the methods of Specification 707,425, and may be any of those specified therein. Preferred polymers are those of an open-chain unsaturated aliphatic diene (e.g. butadiene-1 : 3), of an alkyl ester of acrylic acid, which is then hydrolysed, of a mixture of an olefinically unsaturated carboxylic acid (e.g. methacrylic acid) with either of the above; specified are butadiene-sorbic acid copolymer, butadiene-acrylonitrile-methacrylic acid terpolymer, ethyl acrylate-acrylic acid-methacrylic acid terpolymer (this polymerization may take place in two stages) and ethylacrylate-acrylic acid-methacrylic acid-divinyl benzene tetrapolymer. The mixing may be done in any conventional manner such as mill-mixing, preferably below 175 DEG to 200 DEG F. Preferred curing agents are the polymethylene diamines and the polyethylene diamines, e.g. hexamethylene diamine, its carbonate and its borate and the preferred proportions vary from 1 to 30 per cent based on the weight of polymer. The heating may be carried out until the product has properties comparable to metallocarboxylates (e.g. 150-300 DEG F.) or more drastically to form diamide- or imido-type cross-linkages (e.g. 250-450 DEG F.).