US 12,187,859 B2
Process for producing aqueous fluoropolymer dispersion
Satoru Yoneda, Osaka (JP); Masahiro Higashi, Osaka (JP); Sumi Ishihara, Osaka (JP); Hirotoshi Yoshida, Osaka (JP); Yohei Fujimoto, Osaka (JP); and Yosuke Kishikawa, Osaka (JP)
Assigned to DAIKIN INDUSTRIES, LTD., Osaka (JP)
Appl. No. 17/606,309
Filed by DAIKIN INDUSTRIES, LTD., Osaka (JP)
PCT Filed Apr. 27, 2020, PCT No. PCT/JP2020/018039
§ 371(c)(1), (2) Date Oct. 25, 2021,
PCT Pub. No. WO2020/218618, PCT Pub. Date Oct. 29, 2020.
Claims priority of application No. 2019-085977 (JP), filed on Apr. 26, 2019.
Prior Publication US 2022/0213277 A1, Jul. 7, 2022
Int. Cl. C08J 3/05 (2006.01); C08F 114/26 (2006.01)
CPC C08J 3/05 (2013.01) [C08F 114/26 (2013.01); C08J 2327/18 (2013.01)] 10 Claims
 
1. A method for producing a fluoropolymer aqueous dispersion, comprising a step A of subjecting a pre-treatment aqueous dispersion containing a fluoropolymer obtained by polymerization in the presence of a hydrocarbon surfactant to ultrafiltration, microfiltration, or dialysis membrane treatment, or a combination thereof,
wherein water is added to the pre-treatment aqueous dispersion while performing ultrafiltration, microfiltration, or dialysis membrane treatment, and
the ultrafiltration is performed using an ultrafiltration membrane having a molecular weight cutoff of 0.3×104 Da or more.