Patent ID: 11952442
Assignee: LG CHEM, LTD.
Field: Macromolecular chemistry, polymers (Chemistry)
Classification: CPC C | IPC C

Claim 0:
1. A method for preparing a vinyl chloride-based polymer, the method comprising:
a step of injecting an ionizable normal salt and polymerizing a vinyl chloride monomer in the presence of one or more emulsifiers and a polymerization initiator,
wherein the ionizable normal salt comprises a carbonate metal salt or a sulfite metal salt, wherein the ionizable normal salt is continuously injected in an amount of 70 to 1200 ppm based on the total weight of the vinyl chloride monomer when a polymerization conversion rate is in a range of 0% to 20%,
wherein when the polymerization conversion rate being 0% is a point where polymerization reaction begins immediately after initiating the polymerization of the vinyl chloride monomer,
wherein the polymerization is performed by the steps comprising:
injecting supplementary materials comprising an emulsifier and water to a reactor;
applying vacuum to the reactor and then injecting the polymerization initiator and the vinyl chloride monomer; and
continuously injecting the ionizable normal salt to the reactor after the inner temperature of the reactor reaches 30 to 70° C.