CONTINUOUS COPOLYMERIZATION OF ETHYLENE/VINYL ACETATE

PURPOSE:To prevent the formation of gel-like matter, by specifying the third component and the relationship among the conversion of vinyl acetate, the dwell time within a polymerization tank and the half-life of an initiator, in the titled polymerization process using a lower alcohol solvent and a radical initiator. CONSTITUTION:In the production of a copolymer of formulaI, wherein R is H or methyl, R' is methyl or COOR, X, Y and Z are numbers which satisfy the relationships of formulas II and III; a 1-4C alcohol is used as a polymerization solvent, a radical intitator is used and the solvent concentration is set at below 20wt%. Further, the reaction mixture is continuously polymerized at a temperature of 50-80 deg.C under a condition of formula IV, wherein X is the conversion of vinyl acetate and is below 0.85, THETA is an average dwell time within the polymerization tank and theta is the half-life of the initiator. In this polymerization, the kind and amount of the third component other than ethylene and vinyl acetate need to be controlled as specified in formulasI-III. Unless the conversion (x) of vinyl acetate, THETA and theta are selected so as to satisfy formula IV, no effect can be obtained.