	US 12,460,025 B2
	Polytetrafluoroethylene production method
Yohei Fujimoto, Osaka (JP); Kenji Ichikawa, Osaka (JP); Yoshinori Nanba, Osaka (JP); Taketo Kato, Osaka (JP); and Taku Yamanaka, Osaka (JP)
Assigned to DAIKIN INDUSTRIES, LTD., Osaka (JP)
Filed by DAIKIN INDUSTRIES, LTD., Osaka (JP)
Filed on May 18, 2022, as Appl. No. 17/747,655.
Application 17/747,655 is a continuation of application No. PCT/JP2020/043293, filed on Nov. 19, 2020.
Claims priority of application No. 2019-209153 (JP), filed on Nov. 19, 2019.
Prior Publication US 2022/0289877 A1, Sep. 15, 2022
Int. Cl. C08L 27/18 (2006.01); C08F 2/30 (2006.01); C08F 14/26 (2006.01); C08L 27/12 (2006.01)

CPC C08F 14/26 (2013.01) [C08L 27/12 (2013.01); C08L 27/18 (2013.01); C08F 2/30 (2013.01)]

10 Claims

1. A method for producing polytetrafluoroethylene, comprising polymerizing tetrafluoroethylene in an aqueous medium in the presence of a nucleating agent and a polymer (I) containing a polymerization unit (I) based on a monomer represented by the general formula (I) to obtain polytetrafluoroethylene:

CX¹X³═CX²R(—CZ¹Z²-A⁰)_m (I)

wherein X¹and X³are each independently F, Cl, H, or CF₃; X²is H, F, an alkyl group, or a fluorine-containing alkyl group; A⁰is an anionic group; R is a linking group; Z¹and Z²are each independently H, F, an alkyl group, or a fluorine-containing alkyl group; and m is an integer of 1 or more,

primary particles of the polytetrafluoroethylene have an aspect ratio of less than 2.00, and

the nucleating agent is a chain transfer agent and one or both of a nonionic surfactant and fluoropolyether.