Method for producing a gel-free ethylene / vinyl acetate copolymer having a high content of copolymerized vinyl acetate and a high Mooney viscosity

摘要

Gel-free ethylene-vinyl acetate copolymers having a high content of copolymerised vinyl acetate and a high Mooney viscosity are prepared by carrying out the polymerisation in solution in the presence of from 20 to 45 % by weight of tert-butanol, based on the reaction solution, at temperatures of from 50 to 80 DEG C and pressures of from 300 to 450 bar using azo compounds in a stirred-reactor cascade at a mean residence time of the reaction solution in the reaction cascade of from 5 to 9 hours and a conversion of from 50 to 70 % by weight, based on the vinyl acetate employed. The ethylene-vinyl acetate copolymer prepared by the novel process can be used for the preparation of vulcanisates having improved mechanical properties.