LOW FORMALDEHYDE VINYL ESTER/ETHYLENE EMULSION COPOLYMERS

摘要

A vinyl ester/ethylene copolymer is prepared by emulsion copolymerization of a monomer mixture comprising at least one vinyl ester, ethylene, a stabilizing system comprising polyvinyl alcohol and a free radical redox polymerization initiator system comprising i-butyl hydroperoxide as an oxidizing agent and at least one of a sulfuric acid-based compound and erythorbic acid or a salt thereof as a reducing agent. The monomer mixture comprises from 70 wt % to 95 wt % of said at least one vinyl ester and from 5 wt % to 30 wt % of ethylene based on the total weight of monomers in said mixture and the copolymer has a formaldehyde content of less than 5.0 ppmw as determined by ISO-15173.