PRODUCTION OF MODIFIED POLYOLEFIN

PROBLEM TO BE SOLVED: To produce a modified polyolefin having a high content of carboxyl group introduced thereinto by mixing a polyolefin with a free-radical generator and an unsaturated carboxylic ester, as the modifying agent, formed from an unsaturated carboxylic acid and a vinyl ether and heating the resultant mixture. SOLUTION: A polyolefin, a free-radical generator preferably in an amount of 0.001-1 mmol per g of the polyolefin, and an unsaturated carboxylic ester (preferably a compound of the formula), as the modifying agent, formed from an unsaturated carboxylic acid and a vinyl ether and preferably in an amount of 0.001-1 mmol per g of the polyolefin are mixed and heated preferably to 100-300 deg.C. In the formula, R is a 1-8C linear or branched alkyl group or cyclohexyl. Having a good compatibility with a polyolefin, the unsaturated carboxylic ester is dispersed homogeneously enough in the polyolefin and is grafted thereon, and thus carboxyl groups derived from the ester can be efficiently introduced into the polyolefin.