Method for producing fluoropolymer

Patent metadata

Field	Value
Publication number	US-12492271-B2
Application number	US-202217747547-A
Country	US
Kind code	B2
Filing date	May 18, 2022
Priority date	Nov 19, 2019
Publication date	Dec 9, 2025
Grant date	Dec 9, 2025

Abstract

A method for producing a fluoropolymer, which includes: polymerizing a monomer (I) represented by the general formula (I) below in an aqueous medium substantially in the absence of a fluorine-containing surfactant (except for the monomer (I) represented by the general formula (I)) to obtain a crude composition containing a polymer of the monomer (I); removing a dimer and a trimer of the monomer (I) contained in the crude composition from the crude composition to obtain a polymer (I) in which the content of the dimer and trimer of the monomer (I) is 1.0% by mass or less based on the polymer (I); and polymerizing a fluoromonomer in an aqueous medium in the presence of the polymer (I) to obtain a fluoropolymer:

CX 1 X 3 ═CX 2 R(—CZ 1 Z 2 -A 0 ) m   (I)

wherein X 1 and X 3 , X 2 , A 0 , R, Z 1 and Z 2 are as defined herein.

First claim

What is claimed is:

1 . A method for producing a fluoropolymer, the method comprising:
polymerizing a monomer (I) represented by the general formula (I) below in an aqueous medium substantially in the absence of a fluorine-containing surfactant (except for the monomer (I) represented by the general formula (I)) to obtain a crude composition containing a polymer of the monomer (I); removing a dimer and a trimer of the monomer (I) contained in the crude composition from the crude composition to obtain a polymer (I) in which the content of the dimer and trimer of the monomer (I) is 1.0% by mass or less based on the polymer (I); and polymerizing a fluoromonomer in an aqueous medium in the presence of the polymer (I) to obtain a fluoropolymer:
CX 1 X 3 ═CX 2 R(—CZ 1 Z 2 -A 0 ) m   (I)

wherein X 1 and X 3 are each independently F, Cl, H, or CF 3 ; X 2 is H, F, an alkyl group, or a fluorine-containing alkyl group; A 0 is an anionic group; R is a linking group; Z 1 and Z 2 are each independently H, F, an alkyl group, or a fluorine-containing alkyl group; and m is an integer of 1 or more.

2 . The method for production according to claim 1 , wherein the monomer (I) has a molecular weight of 400 or less.

3 . The method for production according to claim 1 , wherein A 0 is —COOM, —SO 3 M, —OSO 3 M, or —C(CF 3 ) 2 OM, where M is —H, a metal atom, —NR 7 4 , imidazolium optionally having a substituent, pyridinium optionally having a substituent, or phosphonium optionally having a substituent, and R 7 is H or an organic group.

4 . The method for production according to claim 1 , wherein A 0 is —COOM, where M is —H, a metal atom, —NR 7 4 , imidazolium optionally having a substituent, pyridinium optionally having a substituent, or phosphonium optionally having a substituent, and R 7 is H or an organic group.

5 . The method for production according to claim 1 , wherein the monomer (I) is a monomer represented by the following general formula (1):
CX 2 ═CY(—CZ 2 —O—Rf-A)  (1)
wherein X is the same or different and is —H or —F; Y is —H, —F, an alkyl group, or a fluorine-containing alkyl group; Z is the same or different and is —H, —F, an alkyl group, or a fluoroalkyl group; Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms or a fluorine-containing alkylene group having 2 to 100 carbon atoms and having an ether bond; and A is —COOM, —SO 3 M, —OSO 3 M, or —C(CF 3 ) 2 OM, where M is —H, a metal atom, —NR 7 4 , imidazolium optionally having a substituent, pyridinium optionally having a substituent, or phosphonium optionally having a substituent, and R 7 is H or an organic group, with the proviso that at least one of X, Y, and Z contains a fluorine atom.

6 . The method for production according to claim 1 , wherein the monomer (I) is a monomer represented by the following general formula (1A):
CH 2 ═CF(—CF 2 —O—Rf-A)  (1A)
wherein Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms or a fluorine-containing alkylene group having 2 to 100 carbon atoms and having an ether bond; and A is —COOM, —SO 3 M, —OSO 3 M, or —C(CF 3 ) 2 OM, where M is —H, a metal atom, —NR 7 4 , imidazolium optionally having a substituent, pyridinium optionally having a substituent, or phosphonium optionally having a substituent, and R 7 is H or an organic group.

7 . The method for production according to claim 5 , wherein A is —COOM, where M is —H, a metal atom, —NR 7 4 , imidazolium optionally having a substituent, pyridinium optionally having a substituent, or phosphonium optionally having a substituent, and R 7 is H or an organic group.

8 . The method for production according to claim 1 , wherein the dimer and trimer of the monomer (I) are removed from the crude composition by ultrafiltration of the crude composition.

Assignees

• Daikin Ind Ltd

Inventors

• Yamanaka Taku
• Higashi Masahiro
• Kato Taketo
• Ichikawa Kenji
• Fujimoto Yohei
• Irie Masaki
• Tsuchiya Soushi
• Yuasa Souta

Classifications

• C08F14/185

  Monomers containing fluorine not covered by the groups C08F14/20 - C08F14/28 · CPC title

• C08F114/26

  Tetrafluoroethene · CPC title

• C08F214/26

  Tetrafluoroethene · CPC title

• C08F214/262

  with fluorinated vinyl ethers · CPC title

• C08F14/26 Primary

  Tetrafluoroethene · CPC title