Propylene copolymer grafted with monomaleimide

PURPOSE: To obtain a propylene graft copolymer which contains a comonomer relatively hard to volatilize and gives a high degree of graft bonding or formation in polymerization even when the proportion of the comonomer to be grafted is high by grafting a propylene copolymer with monomaleimide in a specified mode. CONSTITUTION: This graft copolymer is obtained by reacting (a) a polymer containing 25-97 wt.% propylene copolymer having a polymerized 2-10C 1-alkene content of 0.1-15 wt.% and 3-75 wt.% other propylene copolymer having a polymerized 2-10C 1-alkene content of 15-80 wt.%, or the like, with (b) a monomaleimide compound represented by the formula at 180-280°C under a pressure of 1-100 bar and with average residence times of the reaction mixture of 0.2-10 min. In the formula, R is a 1-10C alkyl which may be interrupted by one or more oxygen atoms, a 5-10C cycloalkyl, a 5-12C aryl, a 7-18C aromatic alkyl or the like. COPYRIGHT: (C)1995,JPO