PURPOSE: To prepare a terpolymer rubber having excellent oil resistance, heat resistance and solvent resistance, by the emulsion polymerization of a conjugated diene, an unsaturated nitrile compound and an unsaturated carboxylic acid ester, followed by the treatment of the resulting polymer with an alkali and the coagulation of the product with a specific coagulant.
CONSTITUTION: A terpolymer latex consisting of 5W50wt.% of a conjugated diene, 10W50wt.% of an α, β-unsaturated nitrile compound and 10W80wt.% of an α, β- unsaturated carboxylic acid ester, is prepared by emulsion polymerization. An alkali metal hydroxide (2W30 times mole on the basis of the amount of the residual unsaturated carboxylic acid) is added to the latex and stirred at 50W80°C for ≥ 10 min. An aqueous solution containing 0.1W1.0% of an inorganic acid and 1W 10% of an alkali metal salt or an aqueous solution containing 0.5W5% of aluminum sulfate [200W600 parts by weight on the basis of 100 parts by weight of the latex (solid content 15W30%)], is added to the mixture as a coagulant to coagulate the terpolymer rubber.
TAKEMURA YASUHIKO
FURUTA ISAO
