CN-121986127-A - Method for producing fluorine-containing polymer

Abstract

Provided is a method for producing a fluoropolymer, which can produce a fluoropolymer having excellent heat resistance. A method for producing a fluoropolymer by polymerizing a monomer containing a perfluoroolefin having 2-8 carbon atoms with a polymerization initiator X in an aqueous dispersion liquid containing a polymer having a hydrophilic group and an aqueous medium, wherein the polymerization initiator X has no hydrophilic group and has a molecular weight of 200 or less.

Inventors

• SHIBASAKI HIROAKI
• JI XUJUN
• NARUMI MIZUNA
• TAGUCHI DAISUKE

Assignees

• ＡＧＣ株式会社

Dates

Publication Date

20260505

Application Date

20241021

Priority Date

20231023

Claims (4)

1. 1. A method for producing a fluoropolymer by polymerizing a monomer containing a perfluoroolefin having 2 to 8 carbon atoms with a polymerization initiator X in an aqueous dispersion liquid containing a polymer having a hydrophilic group and an aqueous medium, Wherein the polymerization initiator X has no hydrophilic group and has a molecular weight of 200 or less.
2. 2. The method for producing a fluoropolymer according to claim 1, wherein said polymerization initiator X is a compound represented by the formula (X), R 1 -CO-O-O-R 2 (X) In the formula (X), R 1 and R 2 are each independently an alkyl group having 1 to 5 carbon atoms.
3. 3. The method for producing a fluorine-containing polymer according to claim 1 or 2, wherein the polymer having a hydrophilic group is a fluorine-containing polymer having a hydrophilic group.
4. 4. The method for producing a fluorine-containing polymer according to claim 1 or 2, wherein the polymer having a hydrophilic group comprises a tetrafluoroethylene-based unit and a perfluoro (alkyl vinyl ether) -based unit.

Description

Method for producing fluorine-containing polymer Technical Field The present invention relates to a method for producing a fluoropolymer. Background Fluoropolymers such as tetrafluoroethylene copolymers are used in various industrial fields because of their excellent heat resistance, chemical resistance, flame retardancy, weather resistance, and the like. As a method for producing a fluoropolymer, there is a method of emulsion-polymerizing a fluorine-containing monomer in an aqueous medium using a polymerization initiator having a hydrophilic group (see patent document 1). Prior art literature Patent literature Patent document 1 International publication No. 2020/196779 Disclosure of Invention Problems to be solved by the invention In the method for producing a fluoropolymer of patent document 1, it has been found that there is room for improvement in heat resistance of the resulting fluoropolymer. The present invention addresses the problem of providing a method for producing a fluoropolymer, which can produce a fluoropolymer having excellent heat resistance. Solution for solving the problem The present inventors have conducted intensive studies and as a result, have found that the above-described problems can be solved by the following constitution. [1] A method for producing a fluoropolymer by polymerizing a monomer containing a perfluoroolefin having 2 to 8 carbon atoms with a polymerization initiator X in an aqueous dispersion liquid containing a polymer having a hydrophilic group and an aqueous medium, Wherein the polymerization initiator X has no hydrophilic group and has a molecular weight of 200 or less. [2] The method for producing a fluoropolymer according to [1], wherein the polymerization initiator X is a compound represented by the following formula (X). [3] The method for producing a fluoropolymer according to [1] or [2], wherein the polymer having a hydrophilic group is a fluoropolymer having a hydrophilic group. [4] The method for producing a fluoropolymer according to any one of [1] to [3], wherein the polymer having a hydrophilic group comprises a tetrafluoroethylene-based unit and a perfluoro (alkyl vinyl ether) -based unit. ADVANTAGEOUS EFFECTS OF INVENTION According to the present invention, a method for producing a fluoropolymer that can produce a fluoropolymer having excellent heat resistance can be provided. Detailed Description The meaning of terms in this specification is as follows. In the present specification, the numerical range indicated by "to" means a range including numerical values described before and after "to" as a lower limit value and an upper limit value. In the numerical ranges described in the present specification, the upper limit or the lower limit of a certain numerical range may be replaced with the upper limit or the lower limit of another numerical range described in stages. In the numerical ranges described in the present specification, the upper limit value or the lower limit value described in a certain numerical range may be replaced with the value shown in the embodiment. In the present specification, 1 kind of substance belonging to each component may be used alone, or 2 or more kinds may be used in combination. In the case where 2 or more kinds of substances are used in combination for each component, unless otherwise specified, the content of the component refers to the total content of the substances used in combination. In the present specification, a combination of 2 or more preferred embodiments is a more preferred embodiment. In the present specification, the term "unit" refers to a general term for an atomic group derived from the molecule of the monomer 1 and an atomic group obtained by chemically converting a part of the atomic group, which are directly formed by polymerization of a monomer. The "monomer-based unit" is also simply referred to as "unit" hereinafter. The content (mass% or mole%) of each unit relative to all units contained in the polymer can be obtained by analyzing the polymer by a solid nuclear magnetic resonance spectroscopy (NMR) method, but in general, the content of each unit calculated from the amount of each monomer charged is substantially the same as the actual content of each unit. [ Method for producing fluoropolymer ] In the method for producing a fluorine-containing polymer of the present invention (hereinafter also referred to as "the present production method"), a monomer containing a perfluoroolefin having 2 to 8 carbon atoms (hereinafter also referred to as "specific monomer") is polymerized with a polymerization initiator X in an aqueous dispersion liquid containing a polymer having a hydrophilic group and an aqueous medium to produce a fluorine-containing polymer (hereinafter also referred to as "second fluorine-containing polymer"), The polymerization initiator X has no hydrophilic group and has a molecular weight of 200 or less. The present inventors have found that, as a conventional technique, for exampl