US 12,448,472 B2
Method for producing fluorine-containing polymer, aqueous dispersion liquid, and fluorine-containing polymer composition
Kosuke Shibasaki, Tokyo (JP); Yukiko Hattori, Tokyo (JP); Shinya Higuchi, Tokyo (JP); and Junko Anzai, Tokyo (JP)
Assigned to AGC Inc., Tokyo (JP)
Filed by AGC Inc., Tokyo (JP)
Filed on Sep. 9, 2021, as Appl. No. 17/470,469.
Application 17/470,469 is a continuation of application No. PCT/JP2020/013770, filed on Mar. 26, 2020.
Claims priority of application No. 2019-060003 (JP), filed on Mar. 27, 2019.
Prior Publication US 2021/0403623 A1, Dec. 30, 2021
Int. Cl. C08F 214/26 (2006.01); C08F 265/04 (2006.01)
CPC C08F 214/267 (2013.01) [C08F 214/265 (2013.01); C08F 265/04 (2013.01); C08F 2800/10 (2013.01)] 9 Claims
 
1. A method for producing a tetrafluoroethylene polymer, comprising:
polymerizing at least one fluorinated monomer selected from the group consisting of tetrafluoroethylene, chlorotrifluoroethylene, and vinylidene fluoride, in an aqueous medium in which no emulsifier is contained, and in the presence of a first polymer having units based on a compound of formula (1), CXY=CR1-L-R2,
where X and Y are each independently a hydrogen atom, a halogen atom or a methyl group,
R1 is a hydrogen atom, a halogen atom or a C1-3 alkyl group,
L is —CO—O—*, —O—CO—* or —O—, provided that * represents the binding position to R2, and
R2 is a cyclic alkyl group, a monovalent aromatic hydrocarbon group or a C1-6 linear alkyl group, provided that the C1-6 linear alkyl group as R2 may have an etheric oxygen atom in a carbon-carbon bond,
wherein the first polymer comprises particles having a volume based cumulative 50% particle size of from 10 to 200 nm,
wherein the tetrafluoroethylene polymer is a tetrafluoroethylene copolymer selected from the group consisting of
a tetrafluoroethylene/ethylene (TFE/E) copolymer having a proportion of E units to a total amount of E and TFE units in a range of 20 to 70 mol %,
a tetrafluoroethylene/perfluoro (alkyl vinyl ether) (TFE/PAVE) copolymer having a proportion of PAVE units of at least 0.1 and less than 20 mol % or the proportion of PAVE units in a range of 20 to 70 mol % with respect to a total amount of TFE and PAVE units, and
a tetrafluoroethylene/hexafluoropropylene (TFE/HFP) copolymer having a proportion of HFP units in a range of 1 to 15 mol % with respect to a total amount of TFE and HFP units.