Fluorine-containing copolymer, method for producing fluorine-containing polymer, particles, and aqueous dispersion

Abstract

Provided is a fluorine-containing copolymer which contains a structural unit derived from a polymerizable monomer A containing a polymerizable group and at least one kind of functional group selected from the group consisting of a ketone, a carbonic acid ester, an aldehyde, a boronic acid ester, and a nitrile. Also provided are applications of said fluorine-containing copolymer.

Description

Fluorine-containing copolymer, method for producing fluorine-containing polymer, particles, and aqueous dispersion

[0001] The present disclosure relates to a fluorinated copolymer, a method for producing a fluorinated polymer, particles, and an aqueous dispersion.

[0002] Fluorine-containing polymers such as tetrafluoroethylene copolymers are used in various industrial fields because of their excellent heat resistance, chemical resistance, flame retardancy, weather resistance, etc. Examples of methods for producing fluorine-containing copolymers include a method of emulsion polymerization of fluorine-containing monomers in an aqueous medium using a fluorine-containing emulsifier (see Patent Document 1).

[0003] International Publication No. 2007 / 046377

[0004] There have been cases where fluorine-containing copolymers are required to have improved adhesive properties.

[0005] The present disclosure has been made in view of the above circumstances, and a problem to be solved by one embodiment of the present invention is to provide a fluorinated copolymer having excellent adhesiveness, and a method for producing the fluorinated copolymer. A problem to be solved by another embodiment of the present invention is to provide particles and an aqueous dispersion containing the above fluorinated copolymer.

[0006] The present disclosure includes the following aspects: <1> A fluorine-containing copolymer comprising a structural unit derived from a polymerizable monomer A comprising a polymerizable group and at least one functional group selected from the group consisting of a ketone, a carbonate ester, an aldehyde, a boronate ester, and a nitrile. <2> The fluorine-containing copolymer according to <1>, wherein the polymerizable monomer A is a compound represented by the following formula (1) or formula (2): In formula (1), X １１ , X １２ , and X １３ are each independently a hydrogen atom, a fluorine atom, a chlorine atom, an alkyl group, a group represented by the formula (Y １ ), formula (Y ３ ), formula (Y ４ ), or the formula (Y ５ ) and Y １０ is the formula (Y １ ), formula (Y ３ ), formula (Y ４), or the formula (Y ５ ) and X １１ is an alkyl group and Y is a group of the formula (Y １ ), then X １１ and R １４ may be linked to each other to form a ring. １１ is an alkyl group and Y is a group of the formula (Y ３ ), then X １１ and R ３４ may be linked to each other to form a ring. １１ is an alkyl group and Y is a group of the formula (Y ４ ), then X １１ and R ４４ may be linked to each other to form a ring. １１ is an alkyl group and Y is a group of the formula (Y ５ ), then X １１ and R ５４ and may be linked to each other to form a ring. １ ) middle, R １４ is an alkylene group, and R １５ is a hydrogen atom, a fluorine atom, a chlorine atom, or an alkyl group, and R １５ is an alkyl group, R １４ and R １５ and may be linked to each other to form a ring. ３ ) middle, R ３４ is an alkylene group, and R ３５ is an alkyl group, and R ３４ and R ３５ and may be linked to each other to form a ring. ４ ) middle, R ４４ is an alkylene group, and R ４５ and R ４６ are each independently an alkyl group; R ４５ and R ４６ and may be linked to each other to form a ring. ５ ) middle, R ５４ is an alkylene group. ２１ and R ２２ are all alkylene groups or oxygen atoms. * represents a bonding site. <3> In formula (1), X１１ , X １２ , and X １３ are each independently a hydrogen atom, a fluorine atom, a chlorine atom, or an alkyl group. <4> The fluorine-containing copolymer according to any one of <1> to <3>, further comprising a structural unit derived from at least one polymerizable monomer B selected from the group consisting of tetrafluoroethylene, chlorotrifluoroethylene, and vinylidene fluoride. <5> A method for producing a fluorine-containing copolymer, comprising a step of polymerizing a monomer composition containing a polymerizable monomer A having a polymerizable group and at least one functional group selected from the group consisting of a ketone, a carbonate ester, an aldehyde, a boronate ester, and a nitrile, and at least one polymerizable monomer B selected from the group consisting of tetrafluoroethylene, chlorotrifluoroethylene, and vinylidene fluoride, to produce the fluorine-containing copolymer. <6> A method for producing a fluorine-containing copolymer according to <5>, comprising polymerizing the monomer composition in an aqueous dispersion containing a polymer and an aqueous medium. <7> Particles comprising the fluorine-containing copolymer according to any one of <1> to <4> and a polymer containing structural units derived from tetrafluoroethylene and structural units derived from perfluoro(alkyl vinyl ether). <8> Particles according to <7>, in which the amount of the structural units derived from polymerizable monomer A is 1.0 μmol / g to 100 μmol / g relative to the total mass of the particles. <9> An aqueous dispersion comprising an aqueous medium, the fluorine-containing copolymer according to any one of <1> to <4>, and a polymer containing structural units derived from tetrafluoroethylene and structural units derived from perfluoro(alkyl vinyl ether).

[0007] According to one embodiment of the present invention, there are provided a fluorocopolymer having excellent adhesiveness, and a method for producing the fluorocopolymer. According to another embodiment of the present invention, there are provided particles and an aqueous dispersion containing the fluorocopolymer.

[0008] In the present disclosure, numerical ranges indicated using "to" include the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In numerical ranges described in stages in the present disclosure, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another staged numerical range. Furthermore, in numerical ranges described in the present disclosure, the upper or lower limit value of that numerical range may be replaced with a value shown in the examples. In the present disclosure, when multiple substances corresponding to each component are present in the composition, the amount of each component in the composition means the total amount of the multiple substances present in the composition, unless otherwise specified. In the present disclosure, a combination of two or more preferred embodiments is a more preferred embodiment. In the present disclosure, the term "process" includes not only independent processes but also processes that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved.

[0009] [Fluorocopolymer] The fluorine-containing copolymer of the present disclosure contains a constituent unit derived from a polymerizable monomer A containing a polymerizable group and at least one functional group selected from the group consisting of ketone, carbonate ester, aldehyde, boronate ester, and nitrile.

[0010] The fluorine-containing copolymer of the present disclosure is believed to have excellent adhesive properties because it contains, in its constituent units, at least one functional group selected from the group consisting of ketones, carbonate esters, aldehydes, boronate esters, and nitriles.

[0011] Patent Document 1 does not include any description that focuses on the above-mentioned functional groups.

[0012] (Polymerizable Monomer A) The fluorine-containing copolymer of the present disclosure contains a structural unit derived from polymerizable monomer A. Polymerizable monomer A contains a polymerizable group and at least one functional group selected from the group consisting of ketone, carbonate ester, aldehyde, boronate ester, and nitrile. Hereinafter, the functional group contained in polymerizable monomer A may also be referred to as a "specific functional group."

[0013] The polymerizable group may be a cationically polymerizable group or a radically polymerizable group. The radically polymerizable group may be a thermally radically polymerizable group or a photoradically polymerizable group.

[0014] Among these, the polymerizable group is preferably an ethylenically unsaturated group, more preferably a vinyl group.

[0015] The specific functional group may be directly bonded to the polymerizable group, or may be bonded to the polymerizable group via a linking group. The specific functional group contained in the polymerizable monomer A may be of only one type, or may be of two or more types. Furthermore, the specific functional group contained in the polymerizable monomer A may be of only one type, or may be of two or more types.

[0016] The ketone may be a chain ketone or a cyclic ketone. The carbonate ester may be a chain carbonate ester or a cyclic carbonate ester. The boronic acid ester may be a chain boronic acid ester or a cyclic boronic acid ester.

[0017] From the viewpoint of adhesiveness, the specific functional group is preferably a ketone, a carbonate ester, or a boronate ester.

[0018] Specifically, the polymerizable monomer A is preferably a compound represented by the following formula (1) or (2).

[0019]

[0020] In formula (1), X １１ , X １２ , and X １３ are each independently a hydrogen atom, a fluorine atom, a chlorine atom, an alkyl group, a group represented by the formula (Y １ ), formula (Y ３ ), formula (Y ４ ), or the formula (Y ５ ) and Y １０ is the formula (Y １ ), formula (Y ３ ), formula (Y ４ ), or the formula (Y ５ ) and X １１ is an alkyl group and Y is a group of the formula (Y １ ), then X １１ and R１４ may be linked to each other to form a ring. １１ is an alkyl group and Y is a group of the formula (Y ３ ), then X １１ and R ３４ may be linked to each other to form a ring. １１ is an alkyl group and Y is a group of the formula (Y ４ ), then X １１ and R ４４ may be linked to each other to form a ring. １１ is an alkyl group and Y is a group of the formula (Y ５ ), then X １１ and R ５４ and may be linked to each other to form a ring. １ ) middle, R １４ is an alkylene group, and R １５ is a hydrogen atom, a fluorine atom, a chlorine atom, or an alkyl group, and R １５ is an alkyl group, R １４ and R １５ and may be linked to each other to form a ring. ３ ) middle, R ３４ is an alkylene group, and R ３５ is an alkyl group, and R ３４ and R ３５ and may be linked to each other to form a ring. ４ ) middle, R ４４ is an alkylene group, and R ４５ and R ４６ are each independently an alkyl group; R ４５ and R ４６ and may be linked to each other to form a ring. ５ ) middle, R ５４ is an alkylene group. ２１ and R ２２ are all alkylene groups or oxygen atoms. * indicates a bonding site.

[0021] In formula (1), X １１ , X １２ , and X １３ At least one of the formula (Y １), formula (Y ３ ), formula (Y ４ ), or the formula (Y ５ ), the polymerizable monomer A has at least two specific functional groups.

[0022] In formula (1), X １１ , X １２ , and X １３ The alkyl group represented by X may be a linear alkyl group, a branched alkyl group, or a cyclic alkyl group. １１ , X １２ , and X １３ The alkyl group represented by the following formula may or may not contain a fluorine atom. １１ , X １２ , and X １３ The alkyl group represented by the formula (I) may or may not contain a chlorine atom.

[0023] Formula (Y １ ) Medium, R １４ The alkylene group represented by R may be a linear alkylene group, a branched alkylene group, or a cyclic alkylene group. １４ The alkylene group represented by the formula (I) may or may not contain a fluorine atom. １４ The alkylene group represented by the formula (I) may or may not contain a chlorine atom.

[0024] Formula (Y １ ) Medium, R １５ The alkyl group represented by R may be a linear alkyl group, a branched alkyl group, or a cyclic alkyl group. １５ The alkyl group represented by the formula (I) may or may not contain a fluorine atom. １５ The alkyl group represented by the formula (I) may or may not contain a chlorine atom.

[0025] Formula (Y ３ ) Medium, R ３４The alkylene group represented by R may be a linear alkylene group, a branched alkylene group, or a cyclic alkylene group. ３４ The alkylene group represented by the formula (I) may or may not contain a fluorine atom. ３４ The alkylene group represented by the formula (I) may or may not contain a chlorine atom.

[0026] Formula (Y ３ ) Medium, R ３５ The alkyl group represented by R may be a linear alkyl group, a branched alkyl group, or a cyclic alkyl group. ３５ The alkyl group represented by the formula (I) may or may not contain a fluorine atom. ３５ The alkyl group represented by the formula (I) may or may not contain a chlorine atom.

[0027] Formula (Y ４ ) Medium, R ４４ The alkylene group represented by R may be a linear alkylene group, a branched alkylene group, or a cyclic alkylene group. ４４ The alkylene group represented by the formula (I) may or may not contain a fluorine atom. ４４ The alkylene group represented by the formula (I) may or may not contain a chlorine atom.

[0028] Formula (Y ４ ) Medium, R ４５ and R ４６ The alkyl group represented by R may be a linear alkyl group, a branched alkyl group, or a cyclic alkyl group. ４５ and R ４６ The alkyl group represented by the formula (I) may or may not contain a fluorine atom. ４５ and R ４６ The alkyl group represented by the formula (I) may or may not contain a chlorine atom.

[0029] Formula (Y ５) Medium, R ５４ The alkylene group represented by R may be a linear alkylene group, a branched alkylene group, or a cyclic alkylene group. ５４ The alkylene group represented by the formula (I) may or may not contain a fluorine atom. ５４ The alkylene group represented by the formula (I) may or may not contain a chlorine atom.

[0030] In formula (2), R ２１ and R ２２ The alkylene group represented by R may be a linear alkylene group, a branched alkylene group, or a cyclic alkylene group. ２１ and R ２２ The alkylene group represented by the formula (I) may or may not contain a fluorine atom. ２１ and R ２２ The alkylene group represented by the formula (I) may or may not contain a chlorine atom.

[0031] X １１ , X １２ , and X １３ Examples of the alkyl group represented by X include a methyl group. １１ , X １２ , and X １３ Examples of the alkyl group containing a fluorine atom represented by the formula (I) include CF ３ -, CF ２ H-, CH ２ F-, CF ３ CF ２ - is mentioned. １ ) Medium, R １４ The alkylene group represented by the formula (Y) is preferably a linear alkylene group or a cyclic alkylene group. The number of carbon atoms in the alkylene group is preferably 1 to 4, and more preferably 1 to 2. １ ) Medium, R １５ is a hydrogen atom, the formula (Y １ ) represents an aldehyde-containing group. １ ) Medium, R １５ is an alkyl group, the formula (Y １) represents a group containing a ketone. １５ The alkyl group represented by the formula (I) is preferably a linear alkyl group. The alkyl group preferably has 1 to 4 carbon atoms, more preferably 1 or 2 carbon atoms.

[0032] Formula (Y ３ ) represents a group containing a carbonate ester. ３ ) Medium, R ３４ The alkylene group represented by the formula (Y) is preferably a linear alkylene group. The number of carbon atoms in the alkylene group is preferably 1 to 4, and more preferably 1 to 2. ３ ) Medium, R ３５ The alkyl group represented by R is preferably a linear alkyl group. The number of carbon atoms in the alkyl group is preferably 1 to 4, more preferably 1 to 2. From the viewpoint of reactivity, ３４ and R ３５ and preferably combine with each other to form a ring.

[0033] Formula (Y ４ ) represents a group containing a boronic acid ester. ４ ) Medium, R ４４ The number of carbon atoms in the alkylene group represented by the formula (Y ４ ) Medium, R ４５ and R ４６ The alkyl group represented by the formula (I) is preferably a linear alkyl group or a branched alkyl group. The number of carbon atoms in the alkyl group is preferably 1 to 4, and more preferably 1 or 2.

[0034] Formula (Y ５ ) represents a nitrile-containing group. ５ ) Medium, R ５４ The alkylene group represented by the formula (I) is preferably a linear alkylene group. The alkylene group preferably has 1 to 4 carbon atoms, more preferably 1 or 2 carbon atoms.

[0035] In formula (2), R ２１ and R ２２ When both of R are alkylene groups, the compound represented by formula (2) is a cyclic ketone having a polymerizable group. ２１ and R ２２When both R are oxygen atoms, the compound represented by formula (2) is a cyclic carbonate ester having a polymerizable group. ２１ and R ２２ The alkylene group represented by the formula (I) is preferably a linear alkylene group. The number of carbon atoms in each alkylene group is preferably 1 to 4, and more preferably 1 to 2. From the viewpoint of radical polymerizability, it is preferable that the polymerizable monomer A contains only one specific functional group.

[0036] That is, the polymerizable monomer A is a compound represented by formula (1) or formula (2), and in formula (1), X １１ , X １２ , and X １３ are each independently a hydrogen atom, a fluorine atom, a chlorine atom, an alkyl group not containing a fluorine atom, or an alkyl group containing a fluorine atom, and X １１ , X １２ , and X １３ is more preferably a hydrogen atom.

[0037] Specifically, the polymerizable monomer A is preferably a compound represented by the following formula (11), formula (2), formula (13), formula (14), or formula (15), and more preferably a compound represented by formula (11), formula (2), or formula (13).

[0038]

[0039] Details of the symbols in formulas (11), (2), (13), (14), and (15) are as described above.

[0040] Examples of the compound represented by formula (11) include the following compounds.

[0041]

[0042] Examples of the compound represented by formula (2) include the following compounds:

[0043]

[0044] Examples of the compound represented by formula (13) include the following compounds.

[0045]

[0046] Examples of the compound represented by formula (14) include the following compounds:

[0047]

[0048] Examples of the compound represented by formula (15) include the following compounds:

[0049]

[0050] From the viewpoint of adhesiveness, the substance content of the structural unit derived from polymerizable monomer A is preferably 1.0 μmol / g to 100 μmol / g, and more preferably 2.0 μmol / g to 80 μmol / g, relative to the total mass of the particles of the present disclosure described below.

[0051] (Polymerizable Monomer B) The fluorine-containing copolymer of the present disclosure preferably contains, in addition to a constituent unit derived from the polymerizable monomer A, a constituent unit derived from at least one polymerizable monomer B selected from the group consisting of tetrafluoroethylene (hereinafter also referred to as "TFE"), chlorotrifluoroethylene (hereinafter also referred to as "CTFE"), and vinylidene fluoride (hereinafter also referred to as "VdF").

[0052] From the viewpoint of heat resistance, the polymerizable monomer B preferably contains TFE, and more preferably is TFE.

[0053] The content of the structural units derived from polymerizable monomer B is preferably from 30 to 70 mol %, more preferably from 40 to 60 mol %, based on the total amount of the fluorocopolymer. When importance is attached to the heat resistance of the fluorocopolymer, it is preferably from 90 to 99 mol %, more preferably from 95 to 99 mol %.

[0054] The fluorine-containing copolymer of the present disclosure may contain, in addition to the constitutional units derived from the polymerizable monomer A and the polymerizable monomer B, constitutional units derived from other fluorine-containing polymerizable monomers.

[0055] Examples of other fluorine-containing polymerizable monomers include fluoroalkylethylene (hereinafter also referred to as "FAE"), perfluoro(alkyl vinyl ether) (hereinafter also referred to as "PAVE"), allyl ether, and hexafluoropropylene. The constituent unit derived from other fluorine-containing polymerizable monomers may be of only one type or of two or more types.

[0056] Specific examples of FAE include CH2=CH(CF2)2F (hereinafter also referred to as "PFEE"), CH2=CH(CF2)3F, CH2=CH(CF2)4F (hereinafter also referred to as "PFBE"), CH2=CF(CF2)3H, and CH2=CF(CF2)4H, with PFEE or PFBE being preferred.

[0057] The PAVE is preferably a compound represented by formula (10) because of its excellent polymerization reactivity. ２ =CF-O-R ｆ１ ...(10) In formula (10), R ｆ１ represents a perfluoroalkyl group having 1 to 10 carbon atoms. ｆ１ From the viewpoint of better polymerization reactivity, the number of carbon atoms is preferably 1 to 8, more preferably 1 to 6, still more preferably 1 to 5, and particularly preferably 1 to 3. The perfluoroalkyl group may be linear or branched.

[0058] Specific examples of PAVE include perfluoro(methyl vinyl ether) (hereinafter also referred to as "PMVE"), perfluoro(ethyl vinyl ether) (hereinafter also referred to as "PEVE"), and perfluoro(propyl vinyl ether) (hereinafter also referred to as "PPVE").

[0059] The allyl ether is preferably a compound represented by formula (20): CF ２ =CF-CF ２ --O--Rf (20) In formula (20), Rf is a perfluoroalkyl group having 1 to 10 carbon atoms, and the perfluoroalkyl group may have an etheric oxygen atom between carbon atoms.

[0060] The number of carbon atoms in Rf is preferably 2 to 8, more preferably 3 to 8. Rf may be linear, branched, or may contain a ring structure. Examples of Rf include -(CF ２ ) ｍ CF ３ , and −(CF ２ ) ｒ１ -O-(CF ２ ) ｒ２ CF ３ m is an integer of 0 to 9. r1 is an integer of 1 to 9, r2 is an integer of 0 to 8, and r1+r2 is an integer of 1 to 9.

[0061] Among these, m is preferably an integer of 1 to 7, and more preferably an integer of 1 to 5. r1 is preferably an integer of 1 to 6, and more preferably an integer of 1 to 4. r2 is preferably an integer of 1 to 6, and more preferably an integer of 1 to 4.

[0062] In particular, compound (20) is CF ２ =CF-CF ２ -OCF ２ CF ２ CF ３ is preferred.

[0063] Among these, from the viewpoint of more efficient production of the fluorine-containing copolymer, the PAVE is preferably PMVE or PPVE, and more preferably PMVE.

[0064] When the fluorine-containing copolymer contains a constituent unit derived from another fluorine-containing polymerizable monomer, the content of the constituent unit derived from another fluorine-containing polymerizable monomer is preferably from 0.01 to 10.0 mol %, more preferably from 0.10 to 5.0 mol %, based on the total amount of the fluorine-containing copolymer.

[0065] The fluorine-containing copolymer of the present disclosure may contain, in addition to the constitutional units derived from the polymerizable monomer A and the polymerizable monomer B, constitutional units derived from other non-fluorine-containing polymerizable monomers.

[0066] Examples of the other non-fluorine polymerizable monomer include ethylene, propylene, vinyl chloride, and vinylidene chloride. Among them, the other non-fluorine polymerizable monomer preferably contains ethylene, and more preferably is ethylene. The structural unit derived from the other non-fluorine polymerizable monomer may be of only one type or of two or more types.

[0067] When the fluorine-containing copolymer contains a constituent unit derived from another fluorine-free polymerizable monomer, the content of the constituent unit derived from another fluorine-free polymerizable monomer is preferably from 0 to 70 mol %, more preferably from 40 to 60 mol %, based on the total amount of the fluorine-containing copolymer.

[0068] Preferred embodiments of the fluorine-containing polymer are as follows: Aspect 1: The fluorine-containing polymer comprises structural units derived from polymerizable monomer A and polymerizable monomer B, and the structural units derived from polymerizable monomer B comprise structural units derived from TFE and structural units derived from ethylene. In Aspect 1, the structural units derived from polymerizable monomer B preferably comprise structural units derived from TFE, structural units derived from ethylene, and structural units derived from PFBE or PPVE, and more preferably comprise structural units derived from TFE, structural units derived from ethylene, and structural units derived from PFBE.

[0069] The content of the structural units derived from TFE is preferably 30 to 99 mol%, more preferably 40 to 65 mol%, based on the total amount of the fluoropolymer. The content of the structural units derived from ethylene is preferably 30 to 55 mol%, more preferably 35 to 50 mol%, based on the total amount of the fluoropolymer. When the fluoropolymer contains structural units derived from PFBE or PPVE, the content of the structural units derived from PFBE or PPVE is preferably 0.01 to 10 mol%, more preferably 0.1 to 5 mol%, based on the total amount of the fluoropolymer.

[0070] Aspect 2: The fluorine-containing polymer comprises constitutional units derived from polymerizable monomer A and polymerizable monomer B, and the constitutional units derived from polymerizable monomer B comprise constitutional units derived from TFE and constitutional units derived from HFP.

[0071] The content of the structural units derived from TFE is preferably from 80 to 99 mol %, more preferably from 85 to 95 mol %, based on the total amount of the fluoropolymer. The content of the structural units derived from HFP is preferably from 1 to 20 mol %, more preferably from 5 to 15 mol %, based on the total amount of the fluoropolymer.

[0072] Aspect 3: The fluorine-containing polymer comprises structural units derived from polymerizable monomer A and polymerizable monomer B, and the structural units derived from polymerizable monomer B comprise structural units derived from TFE and structural units derived from PAVE. In Aspect 3, the fluorine-containing polymer preferably comprises structural units derived from TFE and structural units derived from PPVE.

[0073] The content of the constitutional units derived from TFE is preferably 90 to 99.9 mol %, more preferably 95 to 99 mol %, based on the total amount of the fluoropolymer. The content of the constitutional units derived from PAVE is preferably 0.01 to 10 mol %, more preferably 1 to 5 mol %, based on the total amount of the fluoropolymer.

[0074] [Method for producing a fluorine-containing copolymer] The method for producing a fluorine-containing copolymer of the present disclosure comprises a step of polymerizing a monomer composition comprising a polymerizable monomer A containing a polymerizable group and at least one functional group selected from the group consisting of a ketone, a carbonate ester, an aldehyde, a boronate ester, and a nitrile, and at least one polymerizable monomer B selected from the group consisting of tetrafluoroethylene, chlorotrifluoroethylene, and vinylidene fluoride, to produce a fluorine-containing copolymer.

[0075] The preferred embodiments of the polymerizable monomer A and the polymerizable monomer B are as described above.

[0076] The monomer composition may contain a polymerizable monomer other than polymerizable monomer A and polymerizable monomer B. Examples of the other polymerizable monomer include the above-mentioned other fluorine-containing polymerizable monomers and other non-fluorine-containing polymerizable monomers. The amount of polymerizable monomer A used is preferably 0.05 to 5.0 mol%, more preferably 0.1 to 3.0 mol%, based on the total amount of the monomer composition used. The amount of polymerizable monomer B used is preferably 30 to 70 mol%, more preferably 40 to 60 mol%, based on the total amount of the monomer composition used. When the heat resistance of the fluorine-containing copolymer is important, the amount is preferably 90 to 99 mol%, more preferably 95 to 99 mol%. The amount of the other fluorine-containing polymerizable monomer used is preferably 0.01 to 10.0 mol%, more preferably 0.10 to 5.0 mol%, based on the total amount of the monomer composition used. The amount of the other non-fluorine-containing polymerizable monomer used is preferably 0 to 70 mol%, more preferably 40 to 60 mol%, based on the total amount of the monomer composition used.

[0077] Preferred embodiments of the monomer composition are as follows: Aspect 1: The monomer composition comprises a polymerizable monomer A and a polymerizable monomer B, and the polymerizable monomer B comprises TFE and ethylene. In Aspect 1, the polymerizable monomer B preferably comprises TFE, ethylene, and PFBE or PPVE, and more preferably comprises TFE, ethylene, and PFBE.

[0078] The content of TFE is preferably 30 to 99 mol%, more preferably 40 to 65 mol%, based on the total amount of the monomer composition. The content of ethylene is preferably 30 to 55 mol%, more preferably 35 to 50 mol%, based on the total amount of the monomer composition. When the monomer composition contains PFBE or PPVE, the content of PFBE or PPVE is preferably 0.01 to 10 mol%, more preferably 0.1 to 5 mol%, based on the total amount of the monomer composition.

[0079] Aspect 2: The monomer composition includes polymerizable monomer A and polymerizable monomer B, and polymerizable monomer B includes TFE and HFP.

[0080] The content of TFE is preferably 80 to 99 mol %, more preferably 40 to 65 mol %, based on the total amount of the monomer composition, and the content of HFP is preferably 30 to 55 mol %, more preferably 35 to 50 mol %, based on the total amount of the monomer composition.

[0081] Aspect 3: The monomer composition includes a polymerizable monomer A and a polymerizable monomer B, and the polymerizable monomer B includes TFE and PAVE. In Aspect 3, the polymerizable monomer B preferably includes TFE and PPVE.

[0082] The content of TFE is preferably 80 to 99 mol %, more preferably 85 to 95 mol %, based on the total amount of the monomer composition, and the content of PAVE is preferably 1 to 20 mol %, more preferably 5 to 15 mol %, based on the total amount of the monomer composition.

[0083] The polymerization of the monomer composition is preferably carried out in the presence of a polymerization initiator. Examples of the polymerization initiator include an oil-soluble radical initiator, a water-soluble radical initiator, and a water-soluble redox catalyst. Specific examples of the oil-soluble radical initiator include oil-soluble organic peroxides such as tert-butyl peroxypivalate (hereinafter also referred to as "PBPV") and diisopropyl peroxydicarbonate (hereinafter also referred to as "IPP"). Specific examples of the water-soluble radical initiator include persulfates such as ammonium persulfate and potassium persulfate, and water-soluble organic peroxides such as disuccinic acid peroxide, bisglutaric acid peroxide, and tert-butyl hydroperoxide (hereinafter also referred to as "TBHP"). Examples of the water-soluble redox catalyst include a combination of an oxidizing agent such as bromic acid or a salt thereof, chloric acid or a salt thereof, persulfuric acid or a salt thereof, permanganic acid or a salt thereof, or hydrogen peroxide with a reducing agent such as sulfurous acid or a salt thereof, hydrogen sulfite or a salt thereof, thiosulfuric acid or a salt thereof, an organic acid, or an inorganic salt. The persulfate is preferably potassium persulfate or ammonium persulfate. The sulfite is preferably sodium sulfite. The inorganic salt may be a combination of sulfate anion, sulfite anion, chloride anion, and metal ion. The metal ion is preferably a transition metal, such as manganese, iron, cobalt, nickel, copper, zinc, cerium, or silver, with iron ion being preferred. The inorganic salt is preferably iron(II) sulfate. The polymerization initiator is preferably an oil-soluble radical initiator or a water-soluble radical initiator, and from the viewpoint of more efficient production of the fluorine-containing polymer, an oil-soluble radical initiator is more preferred, and an oil-soluble organic peroxide is even more preferred. The polymerization initiator may be one type or two or more types.

[0084] The amount of the polymerization initiator used is preferably 0.01 to 5 parts by mass, more preferably 0.01 to 3 parts by mass, and even more preferably 0.01 to 2 parts by mass, per 100 parts by mass of the total amount of the monomer composition used.

[0085] A reducing agent may be used during polymerization of the monomer composition. The amount of the reducing agent used is preferably 0.1 to 2 parts by mass per 100 parts by mass of the total amount of the monomer composition used.

[0086] The monomer composition is added to the reaction system (i.e., polymerization reaction vessel) by a conventional method. For example, the monomer composition may be added to the reaction system continuously or intermittently so that the polymerization pressure reaches a predetermined pressure. The monomer composition may be dissolved in an aqueous medium, and the resulting solution may be added to the reaction system continuously or intermittently. When a polymerization initiator is used, the polymerization initiator may be added to the reaction system all at once or in portions.

[0087] The polymerization temperature is preferably 10 to 95° C., more preferably 15 to 90° C. The polymerization pressure is preferably 0.5 to 4.0 MPaG, more preferably 0.6 to 3.5 MPaG. In the case of batch processing, the polymerization time is preferably 90 to 1,000 minutes, more preferably 90 to 700 minutes.

[0088] In the method for producing the fluorocopolymer of the present disclosure, it is preferable to polymerize the monomer composition in an aqueous dispersion containing the polymer and an aqueous medium.

[0089] By polymerizing a monomer composition in an aqueous dispersion containing a polymer and an aqueous medium, a fluorine-containing copolymer can be efficiently produced without requiring an emulsifier.

[0090] The polymerization of the monomer composition is preferably carried out by emulsion polymerization, and from the viewpoint of environmental load, it is more preferable to carry out emulsion polymerization in an environment substantially free of emulsifiers. Compared to suspension polymerization, emulsion polymerization is superior in that it can produce fine and uniform particles, has a fast reaction rate, is easy to control the molecular weight, and reduces the environmental load. Examples of emulsifiers include known emulsifiers, such as common surfactants. "Substantially free of emulsifiers" means that the content of emulsifier is 0.03 mass ppm or less, preferably 0.02 mass ppm or less, more preferably 0 mass ppm, relative to the total mass of the aqueous medium contained in the aqueous dispersion.

[0091] (Polymer) The type of polymer contained in the aqueous dispersion is not particularly limited, but is preferably da, first polymer b, first polymer c, or first polymer d shown below, more preferably first polymer a, first polymer c, or first polymer d, and even more preferably first polymer a. The polymer contained in the aqueous dispersion is preferably different from the fluorine-containing copolymer polymerized from the monomer composition, and more preferably contains different structural units.

[0092] The first polymer a contains a structural unit derived from TFE and a structural unit derived from PAVE.

[0093] The first polymer b contains at least one structural unit selected from the group consisting of a structural unit derived from a compound represented by the following formula (A) (hereinafter also referred to as "compound A"), a structural unit derived from a compound represented by the following formula (B) (hereinafter also referred to as "compound B"), and a structural unit derived from a compound represented by the following formula (C) (hereinafter also referred to as "compound C"): Formula (A) CXY=CR 1 -L 1 -R 2 Formula (B) CXY=CR 1 -COO-(L 2 -O) n -R 3 Formula (C) CXY=CR 4 -(O) m -CH2-Z-R 5

[0094] In formula (A), X and Y each independently represent a hydrogen atom, a halogen atom, or a methyl group. 1 represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 3 carbon atoms. 1 represents -CO-O-*, -O-CO-* or -O-. 2 represents the bonding position with 2 represents a cyclic alkyl group, a monovalent aromatic hydrocarbon group, or a chain alkyl group having 1 to 6 carbon atoms.

[0095] In formula (B), X, Y and R 1 represent X, Y and R in formula (A), respectively. 1 The definition is the same as that of L. 2represents an alkylene group. 3 represents an alkyl group, an alkyl group in which at least one —CH— in the alkyl group is replaced with —CO—, or a group represented by formula (D). Formula (D) —CO—CR 1 =CXY In formula (D), X, Y and R １ represent X, Y and R in formula (A), respectively. 1 is the same as the definition of

[0096] In formula (C), X and Y are defined as X and Y in formula (A), respectively. 4 represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 3 carbon atoms, or -CO-OCH3. Z represents -CO-O-* or -O-CO-*. However, * is R 4 represents the bonding position with 5 represents an alkyl group; m represents 0 or 1;

[0097] The first polymer c includes a structural unit based on VdF and a structural unit based on at least one selected from the group consisting of HFP, a fluorinated vinyl ether, CTFE, TFE, and a fluorinated allyl ether.

[0098] The first polymer d contains structural units based on at least one selected from the group consisting of TFE and HFP.

[0099] -First Polymer a- The first polymer a includes a structural unit derived from TFE (hereinafter also referred to as a "TFE unit") and a structural unit derived from PAVE (hereinafter also referred to as a "PAVE unit").

[0100] The PAVE is preferably a compound represented by formula (10) because of its excellent polymerization reactivity. ２ =CF-O-R ｆ１ ...(10) In formula (10), R ｆ１ represents a perfluoroalkyl group having 1 to 10 carbon atoms. ｆ１ From the viewpoint of better polymerization reactivity, the number of carbon atoms is preferably 1 to 8, more preferably 1 to 6, still more preferably 1 to 5, and particularly preferably 1 to 3. The perfluoroalkyl group may be linear or branched.

[0101] Specific examples of PAVE include perfluoro(methyl vinyl ether) (hereinafter also referred to as "PMVE"), perfluoro(ethyl vinyl ether) (hereinafter also referred to as "PEVE"), and perfluoro(propyl vinyl ether) (hereinafter also referred to as "PPVE").

[0102] Among these, the PAVE is preferably PMVE or PPVE, and more preferably PMVE, from the viewpoint of more efficient production of the first polymer a.

[0103] In the first polymer a, the content of PAVE units relative to the total of TFE units and PAVE units is 20 to 60 mol %, and from the viewpoint of more efficient production of the fluorinated copolymer, it is preferably 25 to 60 mol %, more preferably 30 to 55 mol %.

[0104] The first polymer a may comprise structural units derived from other monomers other than TFE and PAVE, but from the viewpoint of more efficiently producing fluorine-containing copolymer, it is preferable that the structural units derived from other monomers are not substantially comprised.The structural units derived from other monomers are not substantially comprised, and the content of the structural units derived from other monomers is 0.01 mol% or less relative to the total amount of the first polymer, and 0 mol% is more preferable.When the structural units derived from other monomers are comprised, the other monomer is preferably HFP.

[0105] The method for producing the first polymer a is preferably a method in which monomers including TFE and PAVE are polymerized in an aqueous medium in the presence of a polymerization initiator. This results in the first polymer a dispersed in particulate form in the aqueous medium. The aqueous medium thus obtained, in which the first polymer a particles are dispersed, may be used as the aqueous dispersion as is, or another aqueous medium may be added and used as the aqueous dispersion. Alternatively, the first polymer a may be dispersed in another aqueous medium by solvent substitution and used as the aqueous dispersion. The aqueous dispersion is preferably free of sulfate ions using a sulfate ion removal means such as an anion exchange resin. The polymerization initiator used in the production of the first polymer a is preferably a water-soluble polymerization initiator, more preferably persulfates such as ammonium persulfate, sodium persulfate, or potassium persulfate, or organic polymerization initiators such as disuccinic acid peroxide or azobisisobutylamidine dihydrochloride, more preferably persulfates, and particularly preferably ammonium persulfate. The aqueous medium used in the production of the first polymer a may be water or a mixed solvent of water and a water-soluble organic solvent. Specific examples of the water-soluble organic solvent include tert-butanol, propylene glycol, dipropylene glycol, dipropylene glycol monomethyl ether, and tripropylene glycol.

[0106] —First Polymer b— The first polymer b includes at least one type of structural unit selected from the group consisting of a structural unit derived from a compound represented by formula (A) below (hereinafter also referred to as “compound (A)”), a structural unit derived from a compound represented by formula (B) below (hereinafter also referred to as “compound (B)”), and a structural unit derived from a compound represented by formula (C) below (hereinafter also referred to as “compound (C)”).

[0107] Formula (A) CXY=CR 1 -L 1 -R 2 Formula (B) CXY=CR 1 -COO-(L 2 -O) n -R 3 Formula (C) CXY=CR 4 -(O) m -CH2-Z-R 5

[0108] In formula (A), X and Y each independently represent a hydrogen atom, a halogen atom, or a methyl group. X and Y each independently represent preferably a hydrogen atom, a fluorine atom, or a chlorine atom, and more preferably a hydrogen atom.

[0109] In formula (A), R 1 represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 3 carbon atoms. 1 As the alkyl group, an alkyl group having 1 to 3 carbon atoms is preferred, and a methyl group is more preferred.

[0110] In formula (A), L 1 represents -CO-O-*, -O-CO-* or -O-. 2 represents the bonding position with L 1 As the alkyl group, —CO—O—* or —O—CO—* is preferred, and —CO—O—* is more preferred.

[0111] In formula (A), R 2 represents a cyclic alkyl group, a monovalent aromatic hydrocarbon group, or a chain alkyl group having 1 to 6 carbon atoms. 2 The chain alkyl group having 1 to 6 carbon atoms may have an etheric oxygen atom between the carbon-carbon bonds, and R 2 The hydrogen atoms contained in the cyclic alkyl group, the monovalent aromatic hydrocarbon group, and the chain alkyl group having 1 to 6 carbon atoms may be substituted with halogen atoms. 2 As the alkyl group, a cyclohexyl group, a phenyl group, a chain alkyl group having 1 to 4 carbon atoms, a chain fluoroalkyl group having 1 to 4 carbon atoms, or a chain alkyl group having 2 to 5 carbon atoms and having an etheric oxygen atom between the carbon-carbon bond is preferred, a chain alkyl group having 1 to 4 carbon atoms or a chain fluoroalkyl group having 1 to 4 carbon atoms is more preferred, and a chain alkyl group having 1 to 4 carbon atoms is even more preferred.

[0112] Compound (A) is preferably a compound represented by formula (A-1): Formula (A-1) CH═C(CH)—CO—O—R 21 In formula (A-1), R 21is a cyclohexyl group, a phenyl group, a chain alkyl group having 1 to 4 carbon atoms, a chain fluoroalkyl group having 1 to 4 carbon atoms, or a chain alkyl group having 2 to 3 carbon atoms and an etheric oxygen atom between the carbon-carbon bonds. 21 As the alkyl group, a chain alkyl group having 1 to 4 carbon atoms or a chain fluoroalkyl group having 1 to 4 carbon atoms is preferred, and a chain alkyl group having 1 to 4 carbon atoms is more preferred.

[0113] In formula (B), X, Y and R 1 represent X, Y and R in formula (A), respectively. 1 The definition and preferred embodiments are the same as those of the above.

[0114] In formula (B), L 2 represents an alkylene group. 2 As L, an alkylene group having 1 to 6 carbon atoms is preferred, an alkylene group having 1 to 3 carbon atoms is more preferred, and an ethylene group is even more preferred. 2 The alkylene group may be linear or branched.

[0115] In formula (B), R 3 represents an alkyl group, an alkyl group in which at least one —CH2— in the alkyl group is replaced with —CO— (hereinafter also referred to as a “substituted alkyl group”), or a group represented by formula (D): Formula (D) —CO—CR 1 =CXY In formula (D), X, Y and R １ represent X, Y and R in formula (A), respectively. 1 The definition and preferred embodiments are the same as those of the above.

[0116] In formula (B), R 3 The alkyl group in R is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group. 3 The number of groups represented by -CO- in the substituted alkyl group is preferably 1 to 3, and more preferably 2. The position of -CO- in the substituted alkyl group may be at the terminal of the substituted alkyl group or between -CH2- and -CH2-. 3 The substituted alkyl group is preferably —CO—CH2—CO—CH3.

[0117] In formula (B), n represents an integer of 1 or more, and is preferably an integer of 1 to 100, and more preferably an integer of 1 to 50.

[0118] The compound (B) is preferably a compound represented by formula (B-1), a compound represented by formula (B-2), or a compound represented by formula (B-3): Formula (B-1) CXY=CR 1 -COO-(L 2 -O) n -R 2a Formula (B-2) CXY=CR 1 -COO-(L 2 -O) n -CO-CR 1 =CXY Formula (B-3) CXY=CR 1 -COO-L 2 -O-R 2b In formula (B-1), formula (B-2), and formula (B-3), X, Y, and R 1 represent X, Y and R in formula (A), respectively. 1 In formula (B-1), formula (B-2), and formula (B-3), L 2 and n are L in formula (B), respectively. 2 and n are the same as those defined in formula (B-1). 2a represents an alkyl group. 2b represents a substituted alkyl group.

[0119] In formula (C), X and Y have the same definitions as X and Y in formula (A), and preferred embodiments are also the same.

[0120] In formula (C), R 4 represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 3 carbon atoms, or —CO—OCH3. 4 is preferably an alkyl group having 1 to 3 carbon atoms or —CO—OCH3.

[0121] In formula (C), Z represents —CO—O—* or —O—CO—*, where * is R 4 Z is preferably —O—CO—*.

[0122] In formula (C), R 5 represents an alkyl group. 5As the alkyl group, an alkyl group having 1 to 3 carbon atoms is preferred, and a methyl group is more preferred.

[0123] In formula (C), m represents 0 or 1. Preferably, m is 0.

[0124] Compound (C) is preferably a compound represented by formula (C-1): Formula (C-1) CXY=CR 4a -CH2-O-CO-R 5 In formula (C-1), X and Y are defined as X and Y in formula (A), respectively. 5 is R in formula (C) 5 The definition is the same as that of R. 4a represents an alkyl group having 1 to 3 carbon atoms.

[0125] The method for producing the first polymer b is preferably a method of polymerizing a monomer containing at least one selected from the group consisting of compound (A), compound (B), and compound (C) in an aqueous medium in the presence of a polymerization initiator, thereby obtaining the first polymer b dispersed in the aqueous medium in the form of particles.

[0126] The polymerization initiator and the aqueous medium used in the production of the first polymer b may be the same as the polymerization initiator and the aqueous medium used in the production of the first polymer a.

[0127] -First Polymer c- The first polymer c includes a structural unit based on VdF and a structural unit based on at least one selected from the group consisting of HFP, a fluorinated vinyl ether, CTFE, TFE, and a fluorinated allyl ether. Note that a polymer including a structural unit derived from TFE and a structural unit derived from PAVE is the first polymer a, and is not the first polymer c.

[0128] In the first polymer c, the content of the structural unit based on VdF is preferably from 30 to 70 mol %, more preferably from 30 to 65 mol %, based on the total amount of the first polymer c.

[0129] The fluorine-containing vinyl ether is preferably a compound represented by the following formula (50), from the viewpoint of excellent polymerization reactivity in producing the first polymer c and enabling more efficient production of the second fluorine-containing polymer:

[0130] CX １１ X １２ =CX １３ -O-(CX １４ X １５ ) ｍ１ -L １ - (CX １６ X １７ ) ｎ１ -A １ …(50)

[0131] In formula (50), X １１ , X １２ , X １３ , X １４ , X １５ , X １６ , and X １７ are each independently a hydrogen atom, a fluorine atom, or a fluoroalkyl group, and X １１ ~X １７ At least one of m is a fluorine atom or a fluoroalkyl group; １ is an integer from 1 to 10, and n １ is an integer from 0 to 10, and L １ is a single bond or a divalent linking group, １ is a hydrogen atom, a fluorine atom, or an ionic functional group.

[0132] X １１ , X １２ , X １３ , X １４ , X １５ , X １６ , and X １７ is preferably a fluorine atom.

[0133] m １ is preferably 1 to 6, more preferably 1 to 3. １ is preferably 0.

[0134] L １ The divalent linking group represented by the following formula (I) is an alkylene group, —CH═CH—, —C≡C—, —O—, —S—, —CO—, —COO—, —OCO—, —CONR １１ -, -NR １２ CO- and combinations thereof are preferred. １１ and R １２are each independently a hydrogen atom or an alkyl group.

[0135] L １ is preferably a single bond.

[0136] A １ The ionic functional group represented by is —SO ３ M, -OSO ３ M, -B(OH) ２ , -P(=O)(OM) ２ , -OP(O)(OM) ２ or -COOM is preferred. M is a hydrogen atom, a metal atom, N(R Ｍ１ ) ４ or P(R Ｍ２ ) ４ When a plurality of M's are present, the plurality of M's may be the same or different from each other.

[0137] R Ｍ１ and R Ｍ２ are each independently a hydrogen atom or a substituent, and R Ｍ１ Any two of R may be bonded to each other to form a ring, and multiple R Ｍ１ may be the same or different from each other, R Ｍ２ Any two of R may be bonded to each other to form a ring, and multiple R Ｍ２ may be the same or different from each other.

[0138] A １ is preferably a hydrogen atom or a fluorine atom, more preferably a fluorine atom.

[0139] Among them, the fluorine-containing vinyl ether is preferably a compound represented by the following formula (50A): CF ２ =CF-O-R ｆ１ ...(50A) In formula (1A), R ｆ１ represents a fluoroalkyl group having 1 to 10 carbon atoms. ｆ１ From the viewpoint of superior polymerization reactivity, the number of carbon atoms is preferably 1 to 8, more preferably 1 to 6, still more preferably 1 to 5, and particularly preferably 1 to 3. The fluoroalkyl group may be linear or branched. The fluoroalkyl group is preferably a perfluoroalkyl group.

[0140] The fluorine-containing vinyl ether is preferably a perfluoroalkyl vinyl ether (hereinafter also referred to as "PAVE").

[0141] Specific examples of PAVE include perfluoro(methyl vinyl ether) (hereinafter also referred to as "PMVE"), perfluoro(ethyl vinyl ether) (hereinafter also referred to as "PEVE"), and perfluoro(propyl vinyl ether) (hereinafter also referred to as "PPVE"). Of these, from the viewpoint of enabling more efficient production of a fluorinated polymer, PMVE or PPVE is preferred as PAVE, and PMVE is more preferred.

[0142] The fluorine-containing allyl ether is preferably a compound represented by the following formula (60), from the viewpoints of excellent polymerization reactivity in producing the first polymer c and of enabling more efficient production of the fluorine-containing polymer.

[0143] CX ２１ X ２２ =CX ２３ (CX ２４ X ２５ )-O-(CX ２６ X ２７ ) ｍ２ -L ２ - (CX ２８ X ２９ ) ｎ２ -A ２ …(60)

[0144] In formula (60), X ２１ , X ２２ , X ２３ , X ２４ , X ２５ , X ２６ , X ２７ , X ２８ , and X ２９ are each independently a hydrogen atom, a fluorine atom, or a fluoroalkyl group, and X ２１ ~X ２９ At least one of m is a fluorine atom or a fluoroalkyl group; ２ is an integer from 1 to 10, and n ２ is an integer from 0 to 10, and L ２ is a single bond or a divalent linking group,２ is a hydrogen atom, a fluorine atom, or an ionic functional group.

[0145] X ２１ , X ２２ , X ２３ , X ２４ , X ２５ , X ２６ , X ２７ , X ２８ , and X ２９ is preferably a fluorine atom.

[0146] m ２ is preferably 1 to 6, more preferably 1 to 3. ２ is preferably 0.

[0147] L ２ The divalent linking group represented by the following formula (I) is an alkylene group, —CH═CH—, —C≡C—, —O—, —S—, —CO—, —COO—, —OCO—, —CONR １１ -, -NR １２ CO- and combinations thereof are preferred. １１ and R １２ are each independently a hydrogen atom or an alkyl group.

[0148] L ２ is preferably a single bond.

[0149] A ２ The ionic functional group represented by is —SO ３ M, -OSO ３ M, -B(OH) ２ , -P(=O)(OM) ２ , -OP(O)(OM) ２ or -COOM is preferred. M is a hydrogen atom, a metal atom, N(R Ｍ１ ) ４ or P(R Ｍ２ ) ４ When a plurality of M's are present, the plurality of M's may be the same or different from each other.

[0150] R Ｍ１ and R Ｍ２ are each independently a hydrogen atom or a substituent, and R Ｍ１ Any two of R may be bonded to each other to form a ring, and multiple RＭ１ may be the same or different from each other, R Ｍ２ Any two of R may be bonded to each other to form a ring, and multiple R Ｍ２ may be the same or different from each other.

[0151] A ２ is preferably a hydrogen atom or a fluorine atom, more preferably a fluorine atom.

[0152] Among these, the fluorine-containing allyl ether is preferably a compound represented by the following formula (60A): CF ２ =CF-CF ２ O-R ｆ２ ... (60A) In formula (60A), R ｆ２ represents a fluoroalkyl group having 1 to 10 carbon atoms. ｆ１ From the viewpoint of superior polymerization reactivity, the number of carbon atoms is preferably 1 to 8, more preferably 1 to 6, still more preferably 1 to 5, and particularly preferably 1 to 3. The fluoroalkyl group may be linear or branched. The fluoroalkyl group is preferably a perfluoroalkyl group.

[0153] The fluorine-containing allyl ether is preferably a perfluoroalkyl allyl ether.

[0154] Specific examples of perfluoroalkyl allyl ethers include perfluoro(methyl allyl ether), perfluoro(ethyl allyl ether), and perfluoro(propyl allyl ether).

[0155] Among these, from the viewpoint of heat resistance, the first polymer c preferably contains a structural unit based on VdF and a structural unit based on at least one selected from the group consisting of HFP and TFE, and more preferably contains a structural unit based on VdF and a structural unit based on HFP, or a structural unit based on VdF, a structural unit based on HFP, and a structural unit based on TFE.

[0156] In the first polymer c, the total content of structural units based on at least one selected from the group consisting of HFP and TFE is preferably 30 to 70 mol %, and more preferably 35 to 70 mol %, relative to the total amount of the first polymer c.

[0157] The first polymer c may contain other structural units in addition to structural units based on VdF, HFP, fluorinated vinyl ether, CTFE, TFE, and fluorinated allyl ether. From the viewpoint of more efficient production of the fluorinated polymer, it is preferable that the first polymer c is substantially free of other structural units. "Substantially free of other structural units" means that the content of other structural units is 0.01 mol% or less, more preferably 0 mol%, based on the total amount of the first polymer c.

[0158] -First Polymer d- The first polymer d includes a structural unit based on at least one selected from the group consisting of TFE and HFP. A polymer including a structural unit derived from TFE and a structural unit derived from PAVE is considered to be the first polymer a, and not the first polymer d. Furthermore, a polymer including a structural unit based on VdF and a structural unit based on at least one selected from the group consisting of HFP, a fluorinated vinyl ether, CTFE, TFE, and a fluorinated allyl ether is considered to be the first polymer c, and not the first polymer d.

[0159] The first polymer d may contain other structural units than structural units based on TFE and HFP, and preferably contains structural units based on other monomers than TFE and HFP. Examples of the other monomers than TFE and HFP include PAVE, propylene, VdF, CH ２ =CF-CF ２ -O-Rf-COOH, CH ２ =CF-CF ２ —O—Rf—SO ３ H, C.F. ２ =CF-CF ２ -O-Rf-COOH, CF ２ =CF-CF ２ —O—Rf—SO ３ H, CH ２ =CF-O-Rf-COOH, CH２ =CF-O-Rf-SO ３ H, C.F. ２ ═CF—O—Rf-COOH and CF ２ =CF-O-Rf-SO ３ H (Rf represents a perfluoroalkyl group having 1 to 10 carbon atoms, and the perfluoroalkyl group may have an etheric oxygen atom between the carbon atoms.) When the first polymer d contains a structural unit based on TFE, the content of the structural unit based on TFE is preferably 10 to 90 mol%, more preferably 30 to 85 mol%, and even more preferably 40 to 80 mol%, relative to the total amount of the first polymer d. When the first polymer d contains a structural unit based on HFP, the content of the structural unit based on HFP is preferably 30 to 95 mol%, more preferably 40 to 90 mol%, and even more preferably 50 to 85 mol%, relative to the total amount of the first polymer d.

[0160] In terms of improving the polymerization reactivity of the first polymer d and improving the effects of the present disclosure, it is preferable that the first polymer d contains a structural unit based on PAVE. Preferred aspects of PAVE are as described above.

[0161] When the first polymer d contains a structural unit based on PAVE, the content of the structural unit based on PAVE is preferably 20 to 95 mol %, more preferably 25 to 80 mol %, and even more preferably 30 to 60 mol %, relative to the total amount of the first polymer d.

[0162] In terms of excellent polymerization reactivity of the first polymer d and better effects of the present disclosure, it is also preferable that the first polymer d contains a structural unit based on at least one selected from the group consisting of propylene and VdF.

[0163] When the first polymer d contains structural units based on propylene, the content of the structural units based on propylene is preferably 5 to 90 mol %, more preferably 8 to 70 mol %, and even more preferably 10 to 60 mol %, relative to the total amount of the first polymer d. When the first polymer d contains structural units based on VdF, the content of the structural units based on VdF is preferably 5 to 90 mol %, more preferably 8 to 80 mol %, and even more preferably 10 to 70 mol %, relative to the total amount of the first polymer d.

[0164] The first polymer d preferably contains any combination of TFE-based structural units and PAVE-based structural units; TFE-based structural units and propylene-based structural units; and HFP-based structural units and VdF-based structural units. When the first polymer d contains TFE-based structural units and PAVE-based structural units, the content of the PAVE-based structural units is preferably 20 to 95 mol%, more preferably 25 to 80 mol%, and even more preferably 30 to 60 mol%, relative to the total content of the TFE- and PAVE-based structural units. When the first polymer d contains TFE-based structural units and PAVE-based structural units, the total content of the TFE- and PAVE-based structural units is preferably 99.0 to 100.0 mol%, more preferably 99.5 to 100.0 mol%, and even more preferably 99.9 to 100.0 mol%, relative to the content of the first polymer d. When the first polymer d contains structural units based on TFE and structural units based on propylene, the content of the structural units based on propylene is preferably 5 to 90 mol%, more preferably 8 to 70 mol%, and even more preferably 10 to 60 mol%, relative to the total content of the structural units based on TFE and propylene. When the first polymer d contains structural units based on TFE and structural units based on propylene, the total content of the structural units based on TFE and propylene is preferably 99.0 to 100.0 mol%, more preferably 99.5 to 100.0 mol%, and even more preferably 99.9 to 100.0 mol%, relative to the content of the first polymer d. When the first polymer d contains structural units based on HFP and structural units based on VdF, the content of the structural units based on VdF is preferably 5 to 90 mol%, more preferably 8 to 80 mol%, and even more preferably 10 to 70 mol%, relative to the total content of the structural units based on HFP and VdF. When the first polymer d contains a structural unit based on HFP and a structural unit based on VdF, the total content of the structural units based on HFP and VdF relative to the content of the first polymer d is preferably 99.0 to 100.0 mol %, more preferably 99.5 to 100.0 mol %, and even more preferably 99.9 to 100.0 mol %.

[0165] The first polymer d may contain structural units based on monomers other than those mentioned above, but from the viewpoint of enabling more efficient production of the fluorine-containing polymer, it may be substantially free of structural units based on other monomers. "Substantially free of structural units based on other monomers" means that the content of structural units based on other monomers is 0.01 mol % or less, and preferably 0 mol %, relative to the content of the first polymer d.

[0166] (Aqueous medium) The aqueous dispersion contains an aqueous medium. The aqueous medium contained in the aqueous dispersion may be the aqueous medium used in producing the polymer. Specific examples of the aqueous medium contained in the aqueous dispersion are the same as the specific examples of the aqueous medium used in producing the polymer.

[0167] Before the start of polymerization of the fluorine-containing copolymer, the content of the aqueous medium is preferably from 60 to 99.9 mass%, more preferably from 96 to 99.9 mass%, and still more preferably from 98 to 99.9 mass%, based on the total mass of the aqueous dispersion.

[0168] The aqueous dispersion may contain components other than the polymer and the aqueous medium, such as a chain transfer agent, an emulsifier, and a pH adjuster.

[0169] Specific examples of chain transfer agents include ethyl acetate, methanol, ethanol, t-butyl methyl ether, diethyl ether, n-pentane, cyclohexane, methane, and propane.

[0170] Specific examples of emulsifiers include CF ３ CF ２ -O-CF ２ CF ２ -O-CF ２ COONH ４ , C.F. ３ CF ２ CF ２ OCF (CF ３ ) COOH, sodium lauryl sulfate, Perex SS-H manufactured by Kao Chemical Co., Ltd., Newcol 1305-SN manufactured by Nippon Nyukazai Co., Ltd., and the like.

[0171] Specific examples of pH adjusters include inorganic salts. Specific examples of inorganic salts include phosphates such as disodium hydrogen phosphate and sodium dihydrogen phosphate, and carbonates such as sodium bicarbonate and sodium carbonate. More preferred specific examples of phosphates include disodium hydrogen phosphate dihydrate and disodium hydrogen phosphate dodecahydrate.

[0172] When the aqueous dispersion contains a chain transfer agent, the content of the chain transfer agent is preferably 0.1 to 5 parts by mass relative to 100 parts by mass of the aqueous medium. The amount of the chain transfer agent used is preferably 0.1 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, and even more preferably 0.1 to 10 parts by mass, relative to 100 parts by mass of the specific monomer described below.

[0173] When the aqueous dispersion contains an emulsifier, the content of the emulsifier is preferably 0.01 to 5 parts by mass relative to 100 parts by mass of the aqueous medium.

[0174] When the aqueous dispersion contains a pH adjuster, the content of the pH adjuster is preferably 0.01 to 3.0 parts by mass per 100 parts by mass of the aqueous medium.

[0175] Before starting polymerization of the monomers used in the polymerization of the fluorine-containing copolymer, the concentration of fluoride ions is preferably 100 mass ppm or less, more preferably 50 mass ppm or less, relative to the total mass of the aqueous dispersion, from the viewpoint of polymerization stability.The lower limit can be 0 mass ppm.An example of a method for adjusting the fluoride ion concentration to the above value can be a method of removing sulfate ions using an anion exchange resin during the production of the polymer.Here, fluoride ions may be generated by the reaction between a polymerization initiator (e.g., ammonium persulfate) and a fluorine-containing monomer, and may be contained in the aqueous dispersion.

[0176] The particle of the present disclosure preferably comprises the first polymer a, the first polymer b, the first polymer c or the first polymer d other than the above-mentioned fluorine-containing copolymer, more preferably comprises the first polymer a, the first polymer c or the first polymer d other than the above-mentioned fluorine-containing copolymer, and even more preferably comprises the first polymer a other than the above-mentioned fluorine-containing copolymer.In particular, the particle of the present disclosure preferably comprises the above-mentioned fluorine-containing copolymer and the polymer that comprises TFE unit and PAVE unit.

[0177] The average particle size of the particles is 1 μm or less, preferably 700 nm or less, and more preferably 500 nm or less. The lower limit of the average particle size of the particles is preferably 50 nm from the viewpoint of aggregation.

[0178] In the present disclosure, the average particle size of particle is the particle size at the point where the cumulative volume is 50% on the cumulative curve, which is obtained by measuring particle size distribution by laser diffraction / scattering method and taking the total volume of particle group as 100%.The preferred embodiment of the above-mentioned fluorine-containing copolymer is as mentioned above.The preferred embodiment of the polymer that comprises TFE unit and PAVE unit is the same as that of first polymer a.

[0179] The particles of the present disclosure do not contain emulsifier, or the content of emulsifier is preferably 100 mass ppm or less, more preferably 10 mass ppm or less, even more preferably 5 mass ppm or less, particularly preferably 1 mass ppm or less, based on the total content of the fluorine-containing copolymer and the polymer comprising TFE unit and PAVE unit.According to the production method of the fluorine-containing copolymer of the present disclosure, it is easy to obtain the particles of the present disclosure with a low content of emulsifier.

[0180] The aqueous dispersion of the present disclosure preferably contains, in addition to the above-mentioned fluorine-containing copolymer, a first polymer a, a first polymer b, a first polymer c, or a first polymer d, more preferably contains, in addition to the above-mentioned fluorine-containing copolymer, a first polymer a, a first polymer c, or a first polymer d, and even more preferably contains, in addition to the above-mentioned fluorine-containing copolymer, a first polymer a. In particular, the aqueous dispersion of the present disclosure preferably contains the above-mentioned fluorine-containing copolymer and a polymer containing TFE units and PAVE units.

[0181] Specific examples of the aqueous medium contained in the aqueous dispersion of the present disclosure are the same as the specific examples of the aqueous medium used in the production of the fluorine-containing copolymer described above.

[0182] The content of the aqueous medium is preferably 50 to 99 mass %, more preferably 60 to 99 mass %, and even more preferably 70 to 99 mass %, based on the total mass of the aqueous dispersion of the present disclosure.

[0183] Preferred embodiments of the fluorine-containing copolymer are as described above. Preferred embodiments of the polymer containing TFE units and PAVE units are the same as those of the first polymer a.

[0184] The aqueous dispersion of the present disclosure does not contain an emulsifier, or the content of the emulsifier is preferably 100 ppm by mass or less, more preferably 10 ppm by mass or less, still more preferably 5 ppm by mass or less, and particularly preferably 1 ppm by mass or less, relative to the total content of the fluorocopolymer and the polymer containing TFE units and PAVE units. According to the production method of the fluorocopolymer of the present disclosure, it is easy to obtain an aqueous dispersion of the present disclosure having a low content of emulsifier.

[0185] The fluorine-containing copolymer of the present disclosure, the particles of the present disclosure, and the aqueous dispersion of the present disclosure can be used for the following applications. Fluid transfer components for food manufacturing equipment, such as food packaging films, lining materials, packings, sealing materials, and sheets for fluid transfer lines used in food manufacturing processes; chemical liquid transfer components, such as chemical stoppers, packaging films, lining materials, packings, sealing materials, and sheets for fluid transfer lines used in chemical manufacturing processes; inner lining components for chemical liquid tanks and piping in chemical plants or semiconductor factories; fuel transfer components, such as O-rings, tubes, packings, valve core materials, hoses, and sealing materials used in automotive fuel systems and peripheral devices, and hoses and sealing materials used in automotive automatic transmissions; carburetor flange gaskets, shaft seals, valve stem seals, sealing materials, and hoses used in automotive engines and peripheral devices, as well as other automotive components, such as automotive brake hoses, air conditioner hoses, radiator hoses, and electrical wire coating materials; chemical liquid transfer components for semiconductor manufacturing equipment, such as O-rings, tubes, packings, valve core materials, hoses, sealing materials, rolls, gaskets, diaphragms, and fittings; coating and ink components such as paint rolls, hoses, tubes, and ink containers for coating equipment; food and beverage transport components such as tubes, hoses, belts, packing, and joints, such as food and beverage tubes or food and beverage hoses, food packaging materials, and glass cooking equipment; waste liquid transport components such as tubes and hoses for transporting waste liquid; high-temperature liquid transport components such as tubes and hoses for transporting high-temperature liquids; steam piping components such as tubes and hoses for steam piping; anti-corrosion tapes for piping, such as tapes wrapped around piping on ship decks, etc.; various coating materials, such as electrical wire coating materials, optical fiber coating materials, and transparent surface coating materials and backing agents applied to the light-incident surface of photovoltaic elements in solar cells; sliding components, such as diaphragms and various packings for diaphragm pumps; agricultural films, and weather-resistant covers for various roofing materials and side walls, etc.; interior materials used in the construction field, and glass coating materials, such as non-flammable fire-resistant safety glass; lining materials, such as laminated steel sheets, used in home appliances, etc.; carrier films for fuel cells; Insulating material for high frequency printed circuit boards.

[0186] The fluorine-containing copolymer, the particles, and the aqueous dispersion of the present disclosure can also be suitably used in the following applications: insulating tape for oil drilling, oil transport hoses, hydrogen tanks, separation membranes (microfiltration membranes, ultrafiltration membranes, reverse osmosis membranes, ion exchange membranes, dialysis membranes, gas separation membranes, etc.), electrode binders (for lithium secondary batteries, fuel cells, etc.), copy rolls, furniture, automobile dashboards, covers for home appliances, etc., sliding members (load bearings, yaw bearings, sliding shafts, valves, bearings, bushings, seals, thrust washers, wear rings, pistons, slide switches, gears, cams, belt conveyors, food transport belts, etc.), tension ropes, wear pads, wear strips, tube lamps, test sockets, wafer guides, wear parts for centrifugal pumps, chemical and water supply pumps, tools (shovels, files, saws, etc.), boilers, hoppers, pipes, ovens, baking molds, chutes, racket strings, dies, toilets, container coating materials, power devices, transistors, thyristors, rectifiers, transformers, power MOS FETs, CPUs, heat dissipation fins, metal heat sinks, blades for wind turbines, wind power generation equipment and aircraft, housings for personal computers and displays, electronic device materials, interior and exterior parts of automobiles, sealing materials for processing machines and vacuum ovens that perform heat treatment under low oxygen conditions, plasma processing equipment, and heat dissipation parts in processing units such as sputtering and various dry etching equipment.

[0187] The present invention will be described in detail below with reference to examples. Examples 1 to 9 and 13 to 21 are working examples, and Examples 10 to 12 and 22 are comparative examples. However, the present invention is not limited to these examples.

[0188] <Proportion of each structural unit in the fluorine-containing copolymer> The proportion of each structural unit in the polymer is １９ It was determined by F-NMR analysis and infrared absorption spectrum analysis.

[0189] <Measurement of average particle size> Particle size distribution was measured by laser diffraction / scattering, and a cumulative curve was calculated with the total volume of the particle population taken as 100%. The particle size (D50) at the point on the cumulative curve where the cumulative volume was 50% was taken as the average particle size.

[0190] <Q Value> Using a thermal flow evaluation device (product name "Flow Tester CFT-100EX", manufactured by Shimadzu Corporation), the extrusion rate was measured from an orifice with a diameter of 2.095 mm and a length of 8,000 mm under conditions of a temperature of 297°C and a load of 7.0 kg. <MFR> MFR was measured in accordance with ASTM D3307 under conditions of a temperature of 372°C and a load of 49 N. The mass flowing out of an orifice with a diameter of 2 mm and a length of 8 mm in 10 minutes was measured.

[0191] <Proportion of structural units derived from polymerizable monomer A in particles> First, for each polymerizable monomer A, －１ The molar absorption coefficient at the peak wavelength was calculated by focusing on the peak wavelength on the higher wavelength side. The polymerization solvents and the peak wavelengths were as follows: Allyl methyl carbonate: 1700 to 1900 cm －１ 5-Hexene-2-one: 1600 to 1800 cm －１ 4-pentanal: 1600-1800 cm －１ Allyl cyanide: 1600-1800 cm －１ Allylboronic acid pinacol ester: 3100-3600 cm －１ 4-vinyl-1,3-dioxolan-2-one: 1700 to 1900 cm －１

[0192] Using the calculated molar absorption coefficient, the concentration of polymerizable monomer A incorporated into the polymer was calculated according to the Beer-Lambert law. Absorbance A = εcd, where ε is the molar absorption coefficient (mL / mol cm), c is the concentration in the polymer film (mol / mL), and d is the optical path length (cm). The density of the polymer film was measured in accordance with ASTM-D792. The amount of substance of the structural unit derived from polymerizable monomer A was calculated using the obtained polymer concentration (mol / mL) and the density of the polymer film. Table 1 shows the amount of substance of the structural unit derived from polymerizable monomer A relative to the total mass of the particles.

[0193] Example 1 A 1.2 L stainless steel polymerization vessel was purged with nitrogen, then the pressure was reduced to -0.1 MPaG, and ultrapure water (713 g), sodium sulfite (120 mg), and methyl methacrylate (MMA) (10 mg) were charged. Next, the solution in the polymerization vessel was heated to 50°C with stirring, and 1 mL of a solution (TBHP concentration: 0.195% by mass) prepared by dissolving TBHP as a hydroperoxide in deionized water was poured into the polymerization vessel, and MMA was polymerized. An aqueous solution containing polymethyl methacrylate was obtained as the first polymer b.

[0194] Next, the polymerization vessel containing the resulting aqueous solution containing polymethyl methacrylate was heated to 60°C while stirring, and a mixed monomer mixture of TFE / E = 86 / 14 molar ratio was injected. The polymerization vessel was pressurized to 1.8 MPaG, and methyl acetate (5 ml) and t-butyl alcohol (t-BuOH) (21 g) were injected. 8 ml of a solution (TBHP concentration: 0.195 mass%) prepared by dissolving TBHP in deionized water was injected into the polymerization vessel. Note that sodium sulfite remained in the aqueous solution contained in the polymerization vessel. The amount of methyl acetate used was 0.63 mass% based on the total mass of the aqueous medium. When the pressure inside the polymerization vessel began to decrease, a mixed monomer mixture of TFE / ethylene = 54 / 46 (molar ratio) was added so as to maintain the internal pressure inside the polymerization vessel at 1.8 MPaG, and polymerization was allowed to proceed. Every 10 minutes from the start of polymerization, 1 ml of a solution of TBHP dissolved in deionized water (TBHP concentration: 0.195% by mass) was added. Every time 12 g of the mixed monomer was injected, 2 ml of an aqueous sodium sulfite solution (sodium sulfite concentration: 0.92% by mass) was added to the polymerization tank. In accordance with the consumption of the mixed monomer, 0.5 mL of a mixed solution of PFBE (15 g) and allyl methyl carbonate (15.1 g) was added. When the polymerization time reached 225 minutes, the polymerization tank was cooled to room temperature, and the gas in the polymerization tank was released to the atmosphere. The gas remaining in the reactor was recovered, and the liquid was then extracted. This liquid was designated as aqueous dispersion 1. Aqueous dispersion 1 was a dispersion in which particles (average particle size 110 nm) containing a first polymer b composed of polymethyl methacrylate and a fluorinated copolymer composed of TFE units / ethylene units / PFBE units / allyl methyl carbonate units were dispersed in an aqueous medium. Aqueous Dispersion 1 was cooled to aggregate the particles and obtain a powder. This powder was then dried at 150°C. The Q value of the obtained powder under a load of 7 kg was 8.2 mm 3 The molar ratio of TFE units to ethylene units to PFBE units in the particles was 53.0 / 46.0 / 1.0. The yield was 30 g.

[0195] Example 2 Production of Raw Material Solution A Ultrapure water (717 g), PMVE (63 g), and TFE (10 g) were charged into a 1.3 L stainless steel pressure reactor, and the temperature was raised to 80°C while stirring. Next, an aqueous ammonium persulfate solution (3.6% by mass, 5 mL) was added to initiate polymerization. As the pressure in the reactor decreased with the start of polymerization, TFE was added to maintain the pressure constant. When 2 g of TFE had been injected, the reactor was cooled to terminate the polymerization reaction. The gas remaining in the reactor was recovered, and the liquid was then extracted. This liquid was designated Raw Material Solution A. Raw Material Solution A was freeze-aggregated and then filtered, and the resulting first polymer a was washed with ultrapure water. It was then vacuum-dried at 100°C. NMR analysis of the resulting first polymer a revealed a PMVE unit / TFE unit ratio of 47.3 / 52.7 (molar ratio).

[0196] [Production of Raw Material Solution B] 4 g of Purolite A300 (manufactured by Purolite Corporation), an anion exchange resin, was added to 200 g of the raw material solution A, and the mixture was stirred for 20 minutes. Thereafter, 2 g of the anion exchange resin was added every 20 minutes. 60 minutes after the start of stirring, the raw material solution was separated from the ion exchange resin by filtration, thereby obtaining raw material solution B. Raw material solution B contained particles of the first polymer a (average particle size: 80 nm) dispersed in an aqueous medium, and the content of the first polymer a was 0.53 mass% relative to the total mass of raw material solution B.

[0197] Ultrapure water (343 g) and raw material solution B (370 mL) were charged into a 1.2 L stainless steel pressure reactor to obtain an aqueous dispersion. The aqueous dispersion was heated to 60°C while stirring. A mixed gas (TFE / ethylene = 86 / 14 (molar ratio)) was injected until the pressure inside the reactor reached 1.8 MPaG, and a PBPV AE3000 (product name "ASAHIKLIN AE-3000", manufactured by AGC) solution (50 mass%, 1.67 mL) was added to initiate polymerization. As the pressure inside the reactor decreased with the initiation of polymerization, a mixed monomer (TFE / ethylene = 54 / 46 (mol%)) was added to maintain the pressure constant. In accordance with the consumption of the mixed monomer, 0.5 mL of a mixed liquid of PFBE (21.3 g) and 5-hexen-2-one (21.3 g) was added. When the polymerization time reached 275 minutes, the polymerization vessel was cooled to room temperature, and the gas in the polymerization vessel was released to the atmosphere. After recovering the gas remaining in the reactor, the liquid was extracted. This liquid was designated as aqueous dispersion 2. Aqueous dispersion 2 was a dispersion in which particles (average particle diameter 130.4 nm) containing a first polymer a composed of PMVE units / TFE units and a fluorinated copolymer composed of TFE units / ethylene units / PFBE units / 5-hexene-2-one units were dispersed in an aqueous medium. The aqueous dispersion was cooled, and the particles were coagulated to obtain a powder. Next, this powder was dried at 150°C. The Q value of the obtained powder under a load of 7 kg was 27.0 mm 3 The resulting particles were agglomerated and dried, and the composition was calculated using NMR. The molar ratio of TFE units to ethylene units to PFBE units to PMVE units was 52.4 / 43.4 / 0.9 / 3.4. The yield was 23.5 g.

[0198] <Example 3> Particles containing a fluorine-containing copolymer were obtained in the same manner as in Example 2, except that AE3000 in Example 2 was changed to isododecane. The molar ratio of TFE units / ethylene units / PFBE units / PMVE units in the particles was 52.1 / 43.5 / 0.7 / 3.7. The yield was 21.2 g.

[0199] Example 4 Particles containing a fluorinated copolymer were obtained in the same manner as in Example 2, except that 0.5 mL of a mixed solution of PFBE (13.3 g) and 4-pentanal (9.44 g) was added in accordance with the consumption of the mixed monomers, and the polymerization time was changed to 180 hours. The molar ratio of TFE units / ethylene units / PFBE units / PMVE units in the particles was 53.1 / 43.0 / 0.3 / 3.6. The yield was 21.8 g.

[0200] <Example 5> In accordance with the consumption of the mixed monomers, 0.5 mL of a mixed solution of PFBE (19.9 g) and allyl cyanide (13.5 g) was added, and the polymerization time was changed to 180 hours, but in the same manner as in Example 2, particles containing a fluorine-containing copolymer were obtained. The molar ratio of TFE unit / ethylene unit / PFBE unit / PMVE unit of the particles was 53.8 / 43.4 / 0.7 / 2.1. The yield was 36.6 g.

[0201] <Example 6> In accordance with the consumption of mixed monomers, 0.5mL of the mixed solution of PFBE (18.7g) and allylboronic acid pinacol ester (15.3g) was added, and the polymerization time was changed to 180 hours, but in the same manner as in Example 2, particles containing a fluorine-containing copolymer were obtained.The molar ratio of TFE unit / ethylene unit / PFBE unit / PMVE unit in the fluorine-containing copolymer of particles was 53.5 / 43.6 / 0.5 / 2.4.The yield was 31.8g.

[0202] Example 7 Particles containing a fluorine-containing copolymer were obtained in the same manner as in Example 2, except that 0.5 mL of PFBE and 0.5 ml of 4-vinyl-1,3-dioxolan-2-one were added in accordance with the consumption of the mixed monomers, and the polymerization time was changed to 180 hours. The molar ratio of TFE units / ethylene units / PFBE units / PMVE units in the particles was 53.3 / 43.5 / 1.0 / 2.3. The yield was 34.2 g.

[0203] Example 8 Particles containing a fluorine-containing copolymer were obtained in the same manner as in Example 7, except that AE3000 in Example 7 was changed to isododecane. The molar ratio of TFE units / ethylene units / PFBE units / PMVE units in the particles was 53.2 / 43.2 / 0.9 / 3.7=53.5 / 45.7 / 0.8. The yield was 21.2 g.

[0204] Example 9 Production of Raw Material Liquid A2 Ultrapure water (717 g), PMVE (50 g), and TFE (8 g) were charged into a 1.3 L stainless steel pressure reactor, and the temperature was raised to 90°C with stirring. Next, an aqueous ammonium persulfate solution (3.6 mass%, 5 mL) was added to initiate polymerization. As the pressure in the reactor decreased with the start of polymerization, TFE was added to maintain the pressure constant. When 1 g of TFE had been injected, the reactor was cooled to terminate the polymerization reaction. The gas remaining in the reactor was recovered, and the liquid was then withdrawn. This liquid was designated raw material liquid A2. Raw material liquid A2 was freeze-coagulated and then filtered to obtain a fluoropolymer 1A. Analysis of the resulting fluoropolymer 1A by NMR revealed that the ratio of TFE units to PMVE units was 52 / 48 (molar ratio) and that the Tg was -5.9°C.

[0205] [Production of Raw Material Solution B2] To the above raw material solution A2 (490 g) was added Dowex Monosphere 650C (manufactured by DuPont, cation exchange resin, 20 g). 60 minutes after the start of stirring, the raw material solution and the ion exchange resin were separated by filtration. To the filtered raw material solution, Purolite A300 (manufactured by Purolite, anion exchange resin, 20 g) was added. 60 minutes after the start of stirring, the raw material solution and the ion exchange resin were separated by filtration to obtain raw material solution B2. In raw material solution B2, particles of fluoropolymer 1A (average particle size 52 nm) were dispersed in an aqueous medium, and the content of fluoropolymer 1A was 0.4 mass% based on the total mass of raw material solution B2.

[0206] A 1.0 L stainless steel pressure reactor was charged with ultrapure water (121 g), raw material solution B2 (475 g), PPVE (20 g), and t-BuOMe (0.5 g) to obtain an aqueous dispersion. The aqueous dispersion was heated to 70°C while stirring. TFE was injected into the reactor until the pressure reached 1.0 MPaG, and an aqueous solution of ammonium persulfate (APS) (1.9 mass%, 4 mL) was added to initiate polymerization. As the polymerization began, the pressure in the reactor decreased, so TFE was added to maintain the pressure constant. In accordance with the consumption of TFE, 0.5 mL of 4-vinyl-1,3-dioxolan-2-one was added. When the polymerization time reached 180 minutes, the polymerization vessel was cooled to room temperature, and the gas in the polymerization vessel was released to the atmosphere. The gas remaining in the reactor was recovered, and the liquid was then withdrawn. This liquid was designated as aqueous dispersion 10. Aqueous Dispersion 10 was a dispersion in which particles (average particle diameter 133 nm) containing a first polymer a composed of PMVE units / TFE units and a fluorinated copolymer composed of TFE units / PPVE units / 4-vinyl-1,3-dioxolan-2-one units were dispersed in an aqueous medium. The aqueous dispersion was cooled to cause the particles to aggregate, thereby obtaining a powder. This powder was then dried at 150°C. The MFR of the obtained powder was 35.0 g / 10 min. The ratio of TFE units / PPVE units / PMVE units of the particles was 94.7 / 0.9 / 4.4 (molar ratio). The yield was 25.2 g.

[0207] Example 10 A mixed monomer mixture of TFE / E = 86 / 14 molar ratio was injected into a polymerization vessel containing an aqueous solution containing polymethyl methacrylate as the first polymer b obtained in Example 1, the polymerization vessel was pressurized to 2.6 MPaG, and methyl acetate (5 ml) and t-butyl alcohol (t-BuOH) (21 g) were injected. 8 ml of a solution of TBHP dissolved in deionized water (TBHP concentration: 0.195 wt%) and PFBE (0.73 g) were injected into the polymerization vessel. Note that sodium sulfite used in step 0 remained in the aqueous solution contained in the polymerization vessel. The amount of methyl acetate used was 0.63 wt% relative to the total mass of the aqueous medium. When the pressure in the polymerization vessel began to decrease, a mixed monomer mixture of TFE / E = 54 / 46 molar ratio was added so as to maintain the internal pressure in the polymerization vessel at 2.6 MPaG, and polymerization was allowed to proceed. Every 10 minutes from the start of polymerization, 1 ml of a solution prepared by dissolving TBHP in deionized water (TBHP concentration: 0.195% by mass) was added. Every time 12 g of the mixed monomer was injected, 2 ml of an aqueous sodium sulfite solution (sodium sulfite concentration: 0.92% by mass) was added to the polymerization tank. In accordance with the consumption of the mixed monomer, 0.73 g of PFBE was added to the polymerization tank. When the continuous charging of the mixed monomer reached 100 g, the polymerization tank was cooled to room temperature, and the gas in the polymerization tank was released to the atmosphere. The polymerization time was 377 minutes. The pH of the obtained aqueous dispersion of fluorocopolymer was 4.4, and the solids concentration was approximately 12% by mass. The average primary particle diameter of the fluorocopolymer in the aqueous dispersion was 240 nm. The aqueous dispersion was cooled, and the fluorocopolymer particles were agglomerated to obtain a powder. Next, this fluorocopolymer powder was dried at 150°C. The Q value of the obtained fluorocopolymer powder under a 7 kg load could not be measured. Therefore, when the Q value of the obtained fluorocopolymer powder was measured under a load of 50 kg, it was found to be 100 mm 3 The molar ratio of TFE units / E 2 units / PFBE units in the particles was 54.5 / 44.6 / 0.9.

[0208] Example 11 Ultrapure water (343 g), raw material solution B (370 mL), and PFBE (0.3 g) were charged into a 1.2 L stainless steel pressure reactor to obtain aqueous dispersion A. The aqueous dispersion A was heated to 60°C while stirring. A mixed gas (TFE / ethylene = 86 / 14 (molar ratio)) was injected until the pressure inside the reactor reached 2.6 MPaG, and a solution (40 mass%, 4 cc) of PBPV in isododecane (trade name Marukasol, manufactured by Maruzen Oil Co., Ltd.) was added to initiate polymerization. As the pressure inside the reactor decreased with the start of polymerization, a mixed CG gas (TFE / ethylene = 54 / 46 (mol%)) was added to maintain a constant pressure. PFBE was continuously added so that the concentration was 1 mol% relative to the amount of CG gas added. When 160 g of mixed CG gas had been injected, the reactor was cooled and the polymerization reaction was terminated. The polymerization time was 356 minutes. After recovering the gas remaining in the reactor, the liquid was extracted. This liquid was designated as aqueous dispersion 11. Aqueous dispersion 11 was a dispersion in which particles (average particle diameter 268 nm) comprising a fluorine-containing copolymer consisting of a first polymer a of PMVE unit / TFE unit and a TFE unit / PFBE unit / ethylene unit were dispersed in an aqueous medium, and the solid content concentration was 20.3 mass%. The obtained particles were aggregated and dried, and the composition was calculated using NMR, resulting in a TFE unit / ethylene unit / PFBE unit / PMVE unit=54.3 / 45.1 / 0.93 / 0.6 (molar ratio).

[0209] Example 12 Ultrapure water (121 g), raw material solution B2 (475 g), PPVE (20 g), and t-BuOMe (0.5 g) were charged into a 1.0 L stainless steel pressure reactor to obtain aqueous dispersion A1. Aqueous dispersion B was heated to 70°C while stirring. TFE was injected into the reactor until the pressure reached 1.0 MPaG, and an aqueous solution of ammonium persulfate (APS) (1.9% by mass, 4 mL) was added to initiate polymerization. As the polymerization began, the pressure in the reactor decreased, so TFE was added to maintain the pressure constant. When 60 g of TFE had been injected, the reactor was cooled and the polymerization reaction was terminated. The polymerization time was 238 minutes. The gas remaining in the reactor was recovered, and the liquid was then withdrawn. This liquid was designated aqueous dispersion 12. Aqueous dispersion 12 is a dispersion in aqueous medium that comprises the first polymer a that consists of PMVE unit / TFE unit and the fluorine-containing copolymer that consists of TFE unit / PPVE unit (average particle size 165nm), and the solid content concentration is 7.0% by mass.The obtained particles are aggregated and dried, and then the composition is calculated using NMR, and the result is that TFE unit / PPVE unit / PMVE unit=97.5 / 1 / 1.5 (molar ratio).MFR is 6.5g / 10min.The particles comprise the first perfluoropolymer that comprises TFE unit and PMVE unit, and the second fluoropolymer that comprises TFE unit and PPVE unit.

[0210] Example 13 Production of Raw Material Solution A3 Distilled water (717 g), HFP (42 g), and VdF (4.5 g) were charged into a 1.0 L stainless steel pressure reactor and heated to 90°C with stirring. The pressure inside the reactor when the temperature reached 90°C was 1.98 MPaG. Next, an aqueous ammonium persulfate solution (3.6% by mass, 5 mL) was added to initiate polymerization. The pressure inside the reactor decreased with the start of polymerization, and when the pressure reached 1.81 MPaG, the reactor was cooled and the polymerization reaction was terminated. The polymerization time was 96 minutes. The gas remaining in the reactor was recovered, and the liquid was extracted. This liquid was designated Raw Material Solution A3. Raw Material Solution A was freeze-aggregated and then filtered. The resulting first polymer c was analyzed by NMR, revealing that the VdF unit / HFP unit ratio was 46 / 54 (molar ratio) and the Tg was 2.3°C.

[0211] [Production of Raw Material Solution B3] To the raw material solution A3 (712 g), a cation exchange resin (trade name "Diaion SK1BH", manufactured by Mitsubishi Chemical Corporation) (28.4 g) was added. 60 minutes after the start of stirring, the raw material solution and the cation exchange resin were separated by filtration. To a portion (690 g) of the filtered raw material solution, an anion exchange resin (trade name "Diaion SA10AOH", manufactured by Mitsubishi Chemical Corporation) (20 g) was added. 60 minutes after the start of stirring, the raw material solution and the anion exchange resin were separated by filtration to obtain raw material solution B3. In raw material solution B3, particles of the first polymer c (average particle size 114 nm) were dispersed in an aqueous medium, and the content of the first polymer c was 0.5 mass% relative to the total mass of raw material solution B3.

[0212] Particles containing a fluorinated copolymer were obtained in the same manner as in Example 1, except that the aqueous solution containing polymethyl methacrylate in Example 1 was changed to raw material solution B3. The molar ratio of TFE units / ethylene units / PFBE units / VdF units / HFP units in the particles was 53.4 / 42.7 / 1.0 / 1.3 / 1.7. The yield was 36.2 g.

[0213] Example 14 Particles containing a fluorinated copolymer were obtained in the same manner as in Example 3, except that raw material solution B in Example 3 was changed to raw material solution B3. The molar ratio of TFE units / ethylene units / PFBE units / VdF units / HFP units in the particles was 52.6 / 43.9 / 0.6 / 1.3 / 1.7. The yield was 35.5 g.

[0214] Example 15 Particles containing a fluorinated copolymer were obtained in the same manner as in Example 8, except that raw material solution B in Example 8 was changed to raw material solution B3. The molar ratio of TFE units / ethylene units / PFBE units / VdF units / HFP units in the particles was 52.7 / 44.0 / 0.6 / 1.2 / 1.6. The yield was 37.8 g.

[0215] Example 16 Particles containing a fluorinated copolymer were obtained in the same manner as in Example 9, except that raw material solution B2 in Example 9 was changed to raw material solution B3 and 4-vinyl-1,3-dioxolan-2-one was changed to allylmethyl carbonate. The molar ratio of TFE units / PPVE units / VdF units / HFP units in the particles was 95.1 / 1.0 / 2.2 / 1.7. The yield was 39.2 g.

[0216] Example 17 Particles containing a fluorinated copolymer were obtained in the same manner as in Example 9, except that raw material solution B2 in Example 9 was changed to raw material solution B3 and 4-vinyl-1,3-dioxolan-2-one was changed to 5-hexen-2-one. The molar ratio of TFE units / PPVE units / VdF units / HFP units in the particles was 94.5 / 1.6 / 2.2 / 1.7. The yield was 40.1 g.

[0217] Example 18 Particles containing a fluorinated copolymer were obtained in the same manner as in Example 9, except that raw material solution B2 in Example 9 was changed to raw material solution B3. The molar ratio of TFE units / PPVE units / VdF units / HFP units of the particles was 94.6 / 1.6 / 2.1 / 1.6. The yield was 41.7 g.

[0218] Example 19 Production of Raw Material Solution A4 Ultrapure water (1689 g) and a 50% by weight aqueous solution of sodium 2-acrylamido-2-methyl-1-propanesulfonate (NaAAMPS, corresponding to Compound X) (360 μL, 180 mg of NaAAMPS) were charged into a 3.3 L stainless steel pressure reactor, and the pressure was increased to 2.5 MPaG at 75°C with stirring. Next, a TFE / propylene mixed gas (TFE / P=88 / 12) (molar ratio) was added to adjust the pressure to 2.5 MPa. An aqueous ammonium persulfate solution (14% by weight, 24 g) was added to initiate polymerization. As the pressure in the reactor decreased with the initiation of polymerization, a TFE / propylene mixed gas (TFE / P=56 / 44) (molar ratio) was added to maintain the pressure constant. When 100 g of the TFE / propylene mixed gas had been injected, the reactor was cooled to terminate the polymerization reaction. After recovering the gas remaining in the reactor, the liquid was extracted and used as raw material liquid A4.

[0219] [Production of Raw Material Solution B4] To the raw material solution A4 (330 g), a cation exchange resin, DIAION SK1BH (26.4 g), manufactured by Mitsubishi Chemical Corporation, was added. 60 minutes after the start of stirring, the raw material solution and the ion exchange resin were separated by filtration. To the filtered raw material solution, an anion exchange resin, DIAION SA10AOH (26.4 g), manufactured by Mitsubishi Chemical Corporation, was added. 60 minutes after the start of stirring, the raw material solution and the ion exchange resin were separated by filtration, and the mixture was further diluted with ultrapure water to obtain raw material solution B4. In raw material solution B4, particles of the first polymer d (average particle size 72 nm) were dispersed in an aqueous medium, and the content of the first polymer d was 1.2 mass% relative to the total mass of raw material solution B4.

[0220] Particles containing a fluorine-containing copolymer were obtained in the same manner as in Example 1, except that the aqueous solution containing polymethyl methacrylate in Example 1 was changed to raw material solution B4. The molar ratio of TFE units / ethylene units / PFBE units / propylene units of the particles was 54.2 / 39.5 / 0.8 / 5.5. The yield was 33.1 g.

[0221] Example 20 Particles containing a fluorinated copolymer were obtained in the same manner as in Example 3, except that raw material solution B in Example 3 was changed to raw material solution B4. The molar ratio of TFE units / ethylene units / PFBE units / propylene units of the particles was 54.5 / 39.1 / 1.1 / 5.4. The yield was 34.4 g.

[0222] Example 21 Particles containing a fluorinated copolymer were obtained in the same manner as in Example 8, except that raw material solution B in Example 8 was changed to raw material solution B4. The molar ratio of TFE units / ethylene units / PFBE units / propylene units of the particles was 54.0 / 39.3 / 1.0 / 5.6. The yield was 32.6 g.

[0223] Example 22 Ultrapure water (343 g) and raw material solution B (370 mL) were charged into a 1.2 L stainless steel pressure reactor to obtain an aqueous dispersion. The aqueous dispersion was heated to 60°C while stirring. A mixed gas (TFE / ethylene = 86 / 14 (molar ratio)) was injected into the reactor until the pressure inside the reactor reached 1.8 MPaG, and a 50% by mass solution of PBPV AE3000 (product name "ASAHIKLIN AE-3000", manufactured by AGC) (1.67 mL) was added to initiate polymerization. As the pressure inside the reactor decreased with the initiation of polymerization, a mixed monomer (TFE / ethylene = 54 / 46 (molar ratio)) was added to maintain the pressure constant. In accordance with the consumption of the mixed monomer, PFBE (0.73 g) was added to the polymerization reactor. In accordance with the consumption of the mixed monomer, 0.15 g of propylene was added. When the polymerization time reached 180 minutes, the polymerization vessel was cooled to room temperature and the gas in the polymerization vessel was released to the atmosphere. When the polymerization time reached 180 minutes, the polymerization vessel was cooled to room temperature and the gas in the polymerization vessel was released to the atmosphere. The gas remaining in the reactor was recovered, and the liquid was then extracted. This liquid was designated as aqueous dispersion 16. Aqueous dispersion 16 was a dispersion in which particles (average particle size 182 nm) containing a first polymer a composed of PMVE units / TFE units and a fluorinated copolymer composed of TFE units / ethylene units / PFBE units / propylene units were dispersed in an aqueous medium. The molar ratio of the particles was TFE units / ethylene units / PFBE units / PMVE units / propylene units = 52.8 / 44.6 / 0.6 / 1.2 / 0.8. The yield was 59.9 g.

[0224] The adhesive strength of the obtained particles containing the polymer and the fluorine-containing copolymer was evaluated by the following method.

[0225] The resulting aggregate of particles containing the polymer and fluorine-containing copolymer was press-molded onto a 100 μm-thick fluororesin film and a thermoplastic resin film, and the resulting laminate was melt-bonded at a pressure of 10 MPaG for 5 minutes, after which the laminated film was removed. The resulting laminated film was cut into strips measuring 5 cm in length and 1 cm in width to prepare test pieces. The peel strength of the test pieces was measured using a tensile tester. The bonding time and bonding temperature were set to the values ​​listed under the bonding conditions in Table 1.

[0226] In the table, "-" for each component means that it was not used, and "-" for a physical property value means that it was not measured.

[0227]

[0228]

[0229]

[0230]

[0231] As shown in Tables 1 to 4, in Examples 1 to 9 and 13 to 21, the fluorine-containing copolymers contained a structural unit derived from polymerizable monomer A containing a polymerizable group and at least one functional group selected from the group consisting of ketone, carbonate ester, aldehyde, boronate ester, and nitrile, and therefore were found to have excellent adhesive properties.

[0232] The disclosure of Japanese Patent Application No. 2024-22307, filed on February 16, 2024, is incorporated herein by reference in its entirety. In addition, all documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually indicated to be incorporated by reference.

Claims

1. A fluorine-containing copolymer comprising a structural unit derived from a polymerizable monomer A containing a polymerizable group and at least one functional group selected from the group consisting of ketones, carbonates, aldehydes, boronates, and nitriles.

2. The fluorine-containing copolymer according to claim 1, wherein the polymerizable monomer A is a compound represented by the following formula (1) or (2): In formula (1), X １１ , X １２ , and X １３ are each independently a hydrogen atom, a fluorine atom, a chlorine atom, an alkyl group, a group represented by the formula (Y １ ), formula (Y ３ ), formula (Y ４ ), or the formula (Y ５ ) and Y １０ is the formula (Y １ ), formula (Y ３ ), formula (Y ４ ), or the formula (Y ５ ) and X １１ is an alkyl group and Y is a group of the formula (Y １ ), then X １１ and R １４ may be linked to each other to form a ring. １１ is an alkyl group and Y is a group of the formula (Y ３ ), then X １１ and R ３４ may be linked to each other to form a ring. １１ is an alkyl group and Y is a group of the formula (Y ４ ), then X １１ and R ４４ may be linked to each other to form a ring. １１ is an alkyl group and Y is a group of the formula (Y ５ ), then X １１ and R ５４ and may be linked to each other to form a ring. １ ) middle, R １４ is an alkylene group, and R １５ is a hydrogen atom, a fluorine atom, a chlorine atom, or an alkyl group, and R １５ is an alkyl group, R １４ and R １５ and may be linked to each other to form a ring. ３ ) middle, R ３４ is an alkylene group, and R ３５ is an alkyl group, and R ３４ and R ３５ and may be linked to each other to form a ring. ４ ) middle, R ４４ is an alkylene group, and R ４５ and R ４６ are each independently an alkyl group; R ４５ and R ４６ and may be linked to each other to form a ring. ５ ) middle, R ５４ is an alkylene group. ２１ and R ２２ are all alkylene groups or oxygen atoms. * indicates a bonding site.

3. In the formula (1), X １１ , X １２ , and X １３ and each independently represent a hydrogen atom, a fluorine atom, a chlorine atom, or an alkyl group.

4. The fluorine-containing copolymer according to any one of claims 1 to 3, further comprising a structural unit derived from at least one polymerizable monomer B selected from the group consisting of tetrafluoroethylene, chlorotrifluoroethylene, and vinylidene fluoride.

5. A method for producing a fluorine-containing copolymer, comprising the step of polymerizing a monomer composition comprising: a polymerizable monomer A containing a polymerizable group and at least one functional group selected from the group consisting of ketones, carbonate esters, aldehydes, boronate esters, and nitriles; and at least one polymerizable monomer B selected from the group consisting of tetrafluoroethylene, chlorotrifluoroethylene, and vinylidene fluoride, to produce a fluorine-containing copolymer.

6. The method for producing a fluorine-containing copolymer according to claim 5, wherein the monomer composition is polymerized in an aqueous dispersion containing a polymer and an aqueous medium.

7. A particle comprising the fluorine-containing copolymer according to claim 1 and a polymer containing structural units derived from tetrafluoroethylene and structural units derived from perfluoro(alkyl vinyl ether).

8. The particles according to claim 7, wherein the amount of the constituent units derived from the polymerizable monomer A is 1.0 μmol / g to 100 μmol / g relative to the total mass of the particles.

9. An aqueous dispersion comprising an aqueous medium, the fluorine-containing copolymer according to claim 1, and a polymer containing structural units derived from tetrafluoroethylene and structural units derived from perfluoro(alkyl vinyl ether).

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