	US 12,240,972 B2
	Method for producing vinyl chloride type polymer
Hiroshi Fukudome, Kamisu (JP); Kazuhiro Kumakura, Kamisu (JP); and Toshihiko Kawakubo, Kamisu (JP)
Assigned to Shin-Etsu Chemical Co., Ltd., Tokyo (JP)
Appl. No. 17/619,305
Filed by Shin-Etsu Chemical Co., Ltd., Tokyo (JP)
PCT Filed Jun. 8, 2020, PCT No. PCT/JP2020/022522 § 371(c)(1), (2) Date Dec. 15, 2021, PCT Pub. No. WO2020/255776, PCT Pub. Date Dec. 24, 2020.
Claims priority of application No. 2019-113439 (JP), filed on Jun. 19, 2019.
Prior Publication US 2022/0403150 A1, Dec. 22, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. C08F 2/30 (2006.01); C08L 27/06 (2006.01); C08F 14/06 (2006.01)

CPC C08L 27/06 (2013.01)

6 Claims

1. A method for producing a vinyl chloride type polymer, the method being to produce the vinyl chloride type polymer by polymerizing a vinyl chloride monomer, or a mixture of a vinyl chloride monomer with a monomer copolymerizable with the vinyl chloride monomer in an aqueous medium by using a polymerization reactor, the method comprising:

charging an aqueous solution of a copolymerized polyether having a weight-average molecular weight of 1,000 to 3,500 with a mole ratio of ethylene oxide to propylene oxide in a range of 10/90 to 60/40 into the polymerization reactor with an amount of 0.005 to 0.050 parts by weight as the copolymerized polyether relative to 100 parts by weight of the vinyl chloride monomer,

wherein in the polymerization, the aqueous solution of the copolymerized polyether is added at a polymerization stage with a polymerization rate of 30 to 80%.

3. The method for producing the vinyl chloride type polymer according to claim 1, wherein the polymerization reactor is equipped with a reflux condenser.

4. The method for producing the vinyl chloride type polymer according to claim 3, wherein a volume of the polymerization reactor is 50 m³or more.