Patent ID: 8791183

Claim:
A method for defoaming a vinyl chloride resin slurry, comprising: adding an antifoaming agent to a vinyl chloride resin slurry when a polymerization conversion ratio is within a range of 0 to 90%, wherein the antifoaming agent comprises a mixture of compounds represented by Formula 1 and represented by Formula 2 below: (wherein R 1 is an aliphatic or cycloaliphatic hydrocarbon having a C 1 to C 20 alkyl group, R 2 is independently an aliphatic or cycloaliphatic hydrocarbon having a C 2 to C 20 alkyl group, a is an integer of 1 to 30, which represents a polymerization degree of a structure in which R 1 and R 2 are bonded to silicon (Si), and b is an integer of 5 to 200, which represents a polymerization degree of a structure in which R 1 and R 1 are bonded to silicon (Si)) (wherein R 3 represents an aliphatic, cycloaliphatic or aromatic hydrocarbon having a C 1 to C 20 alkyl group), and wherein the compound of Formula 1 and the compound of Formula 2 are mixed at a weight ratio of 9:1 to 3:7.