METHOD FOR POLYVINYLCHLORIDE-VINYLACETATE COPOLYMER HAVING HIGH BULK DENSITY

摘要

A method for preparing a vinyl chloride-vinyl acetate copolymer is provided to increase the content of vinyl acetate and bulk density and to reduce viscosity, thereby lowering processing temperature and improving fluidity and adhesive strength. A method for preparing a vinyl chloride-vinyl acetate copolymer comprises the steps of injecting 30-70 parts by weight of a vinyl chloride monomer to an initial reaction mixture comprising a vinyl acetate monomer, a polymerization initiator and a cellulose-based suspension and polymerizing it at a temperature of 40-70 deg.C; and injecting the rest of a vinyl chloride monomer (30-70 parts by weight) to the obtained one and suspension polymerizing it. Preferably the rest of a vinyl chloride monomer is injected by injecting 10-40 parts by weight of a vinyl chloride monomer when the conversion of a vinyl chloride monomer is 10-40 % and injecting 10-40 parts by weight of a vinyl chloride monomer when the conversion of a vinyl chloride monomer is 50-70 %.