ANTIOXIDANT FOR POLYMER

PURPOSE:An antioxidant, consisting of a reaction product of a sulfonated polymer with an aromatic amine compound, and capable of giving a high-degree resistance without evaporating even on exposure to a solvent at high temperature for a long time when added to a polymer. CONSTITUTION:An antioxidant prepared by heating a sulfonated polymer derived from polystyrene, polyethylene, butyl rubber, etc., preferably a polystyrenesulfonic acid resin obtained by sulfonating a crosslinked polystyrene with sulfuric acid, having 0.1-10mm.ol sulfonation degree based on one g polymer, and an aromatic amine compound, e.g. p-aminodiphenylamine, of the formula (R1-R3 are H or 1-12C hydrocarbon groups) in a solvent or mixing the sulfonated polymer swollen with water with a solution of the aromatic amine, and agitating the resultant mixture under heating. The antioxidant in an amount of 0.1-10pts.wt. is added to 100pts.wt. polymer.