Method for producing fluororesin

Patent metadata

Field	Value
Publication number	US-12522679-B2
Application number	US-202117907123-A
Country	US
Kind code	B2
Filing date	Mar 24, 2021
Priority date	Mar 26, 2020
Publication date	Jan 13, 2026
Grant date	Jan 13, 2026

Abstract

The present invention pertains to: a fluororesin that includes a residue unit represented by formula (1), and a terminal group represented by formula (2); and a fluororesin that includes a residue unit represented by formula (1) and has a transmittance of 50% or more measured at an optical path length of 10 mm and a wavelength of 275 nm when dissolved in perfluorohexane to produce a 10 wt % perfluorohexane solution.

In formula (1): Rf 1 , Rf 2 , Rf 3 , and Rf 4 each independently represent one selected from the group consisting of fluorine atoms, C1-7 linear perfluoroalkyl groups, C3-7 branched perfluoroalkyl groups, or C3-7 cyclic perfluoroalkyl groups; the perfluoroalkyl groups may have an etheric oxygen atom; Rf 1 , Rf 2 , Rf 3 , and Rf 4 may bond to each other to form a ring having 4 to 8 carbon atoms; and the ring may include an etheric oxygen atom.

In formula (2), i is an integer of 3-20. The present invention provides: a fluororesin that includes an oxolane ring, has suppressed yellowing after heating and melting, and especially has reduced discoloration, even in molding of thick products; and a method for producing said fluororesin.

First claim

The invention claimed is:

1 . A method for producing a fluororesin, comprising:
polymerizing a mixture including a radical polymerization initiator and a monomer to produce the fluororesin including a residue unit of a formula (1) and a terminal group of a formula (2), wherein the fluororesin has a weight average molecular weight Mw of from 5×10 4 to 9.5×10 4 , and a molecular weight distribution Mw/Mn, which is a ratio of the weight average molecular weight Mw to a number average molecular weight Mn, of from 1.2 to 8,

wherein in the formula (1), Rf 1 , Rf 2 , Rf 3 and Rf 4 each independently represent one of the groups consisting of a fluorine atom, a linear perfluoroalkyl group having 1 to 7 carbon atoms, a branched perfluoroalkyl group having 3 to 7 carbon atoms, and a cyclic perfluoroalkyl group having 3 to 7 carbon atoms, the perfluoroalkyl group may have an ethereal oxygen atom, Rf 1 , Rf 2 , Rf 3 and Rf 4 may be linked to each other to form a ring having 4 or more and 8 or less carbon atoms, and the ring may include an ethereal oxygen atom,

wherein in the formula (2), i is an integer of 3 to 20,
the radical polymerization initiator has a formula (4):

wherein in the formula (4), j is an integer of 3 to 20, and
the monomer has a formula (5):

wherein in the formula (5), Rf 5 , Rf 6 , Rf 7 , and Rf 8 each independently represent one of the groups consisting of a fluorine atom, a linear perfluoroalkyl group having 1 to 7 carbon atoms, a branched perfluoroalkyl group having 3 to 7 carbon atoms, and a cyclic perfluoroalkyl group having 3 to 7 carbon atoms, the perfluoroalkyl group may have an ethereal oxygen atom, Rf 5 , Rf 6 , Rf 7 , and Rf 8 may be linked to each other to form a ring having 4 or more and 8 or less carbon atoms, and the ring may include an ethereal oxygen atom.

2 . The method according to claim 1 , wherein the radical polymerization initiator has a formula (6):

3 . The method according to claim 1 , wherein
in the polymerizing, the mixture is further mixed with an organic solvent, and in the organic solvent, at least the monomer is dissolved and at least a part of the resin produced by the polymerization is not dissolved, resulting in precipitation of the resin, and the resin produced by the polymerization precipitates as particles in the organic solvent.

4 . A method for producing a fluororesin, comprising:
polymerizing a mixture including a radical polymerization initiator and a monomer to produce the fluororesin including a residue unit of a formula (1), and when dissolved in perfluorohexane to obtain a 10 wt % perfluorohexane solution, having a transmittance of at least 50% as measured at an optical path length thereof of 10 mm and a wavelength of 275 nm, wherein the fluororesin has a weight average molecular weight Mw of from 5×10 4 to 9.5×10 4 , and a molecular weight distribution Mw/Mn, which is a ratio of the weight average molecular weight Mw to a number average molecular weight Mn, of from 1.2 to 8,

wherein in the formula (1), Rf 1 , Rf 2 , Rf 3 and Rf 4 each independently represent one of the groups consisting of a fluorine atom, a linear perfluoroalkyl group having 1 to 7 carbon atoms, a branched perfluoroalkyl group having 3 to 7 carbon atoms, and a cyclic perfluoroalkyl group having 3 to 7 carbon atoms, the perfluoroalkyl group may have an ethereal oxygen atom, Rf 1 , Rf 2 , Rf 3 and Rf 4 may be linked to each other to form a ring having 4 or more and 8 or less carbon atoms, and the ring may include an ethereal oxygen atom,
the radical polymerization initiator has a formula (2):

wherein in the formula (2), Rf 9 , Rf 10 , Rf 11 , and Rf 12 each independently represent a perfluoroalkyl group having 1 to 20 carbon atoms, the perfluoroalkyl group may have an ethereal oxygen atom, Rf 9 and Rf 10 may be linked to each other to form a ring having 4 or more and 20 or less carbon atoms, Rf 11 and Rf 12 may be linked to each other to form a ring having 4 or more and 20 or less carbon atoms, and the ring may include an ethereal oxygen atom, and
the monomer has a formula (3):

wherein in the formula (3), Rf 5 , Rf 6 , Rf 7 and Rf 8 each independently represent one of the groups consisting of a fluorine atom, a linear perfluoroalkyl group having 1 to 7 carbon atoms, a branched perfluoroalkyl group having 3 to 7 carbon atoms, and a cyclic perfluoroalkyl group having 3 to 7 carbon atoms, the perfluoroalkyl group may have an ethereal oxygen atom, Rf 5 , Rf 6 , Rf 7 and Rf 8 may be linked to each other to form a ring having 4 or more and 8 or less carbon atoms, and the ring may include an ethereal oxygen atom.

5 . The method according to claim 4 , wherein the radical polymerization initiator has a formula (4):

wherein in the formula (4), Rf 13 and Rf 14 each independently represent a perfluoroalkyl group having 3 to 20 carbon atoms, and the perfluoroalkyl group may have an ethereal oxygen atom.

6 . The method according to claim 1 , wherein
in the polymerizing, the mixture is further mixed with an organic solvent, and in the organic solvent, at least the monomer is dissolved and at least a part of the resin produced by the polymerization is not dissolved, resulting in precipitation of the resin, and the resin produced by the polymerization precipitates as particles in the organic solvent.

Assignees

• Tosoh Corp

Inventors

• Sakaguchi Kota
• Iwanaga Kazunari
• Shimono Tomoya
• NAGAI Tomonari
• Yamakawa Hiroshi

Classifications

• C08F2810/40

  taking place solely at one end or both ends of the polymer backbone, i.e. not in the side or lateral chains · CPC title

• C08F2/06

  Organic solvent · CPC title

• C08F124/00 Primary

  Homopolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a heterocyclic ring containing oxygen (cyclic esters of polyfunctional acids C08F118/00; cyclic anhydrides of unsaturated acids C08F120/00, C08F122/00) · CPC title

• C08F24/00

  Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a heterocyclic ring containing oxygen (cyclic esters of polyfunctional acids C08F18/00; cyclic anhydrides of unsaturated acids C08F20/00, C08F22/00) · CPC title

• C08F2/38

  Polymerisation using regulators, e.g. chain terminating agents {, e.g. telomerisation} · CPC title