Method for producing fluorine-containing copolymer

Abstract

A method for producing a fluorine-containing copolymer in which a monomer containing tetrafluoroethylene is polymerized in a polymerization medium containing at least one polymerization solvent (A) selected from the group consisting of compounds represented by formulae (1) to (3). The description in formulae (1)-(3) is omitted. # imgabs0 # CH3-Z2 (3)

Description

Technical Field

[0001] The present disclosure relates to a method for producing a fluorine-containing copolymer. Background Art

[0002] In recent years, fluorinated polymers have been used in various applications by utilizing their excellent properties such as heat resistance, solvent resistance, and chemical resistance.

[0003] As a method for producing a fluorine-based polymer, polymerization methods such as a solution polymerization method, a suspension polymerization method, and an emulsion polymerization method are known.

[0004] For example, Patent Document 1 describes a polymerization reaction of tetrafluoroethylene, acrylic acid, and methylvinylchlorosilane. Prior art literature Patent Literature

[0005] Patent Document 1: Chinese Patent Application Publication No. 112961553 Summary of the invention Technical problem to be solved by the invention

[0006] However, the polymerization rate of the method described in Patent Document 1 is slow, and a method for obtaining a fluorinated copolymer more efficiently has been desired.

[0007] The technical problem to be solved by one embodiment of the present invention is to provide a method for producing a fluorinated copolymer having a faster polymerization rate than conventional methods. Technical solutions adopted to solve technical problems

[0008] The present disclosure includes the following aspects. <1> A method for producing a fluorine-containing copolymer, In a polymerization medium containing a polymerization solvent A of at least one selected from the group consisting of compounds represented by the following formulae (1) to (3), polymerizing with monomers comprising tetrafluoroethylene;

Chemical formula 1

Chemical formula 2

Chemical formula 3

Chemical formula 4

Chemical formula 5

Chemical formula 6

[0009] According to the present disclosure, there is provided a method for producing a fluorinated copolymer having a faster polymerization rate than conventional methods. DETAILED DESCRIPTION

[0010] In the present disclosure, a numerical range expressed by “to” means a range including the numerical values ​​described before and after “to” as a minimum value and a maximum value, respectively. In the numerical ranges recorded in the present disclosure, the upper limit or lower limit recorded in a certain numerical range can be replaced by the upper limit or lower limit of the numerical range recorded in other classifications. In addition, in the numerical ranges recorded in the present disclosure, the upper limit or lower limit recorded in a certain numerical range can also be replaced by the value shown in the embodiments. In the present disclosure, a combination of two or more preferred aspects is a more preferred aspect. In the present disclosure, when there are a plurality of substances corresponding to each component, the amount of each component refers to the total amount of the plurality of substances unless otherwise specifically defined. In this disclosure, "tBu" means "tert-butyl".

[0011] [Method for producing fluorinated copolymer] The method for producing a fluorinated copolymer disclosed herein is a method of polymerizing a monomer containing tetrafluoroethylene in a polymerization medium containing a polymerization solvent A containing at least one selected from the group consisting of compounds represented by the following formulae (1) to (3).

[0012]

Chemical formula 7

[0013]

Chemical formula 8

[0014]

Chemical formula 9

[0015] In formula (1), Y 1 represents a nitrogen atom or an oxygen atom, Y 1 When it is a nitrogen atom, p, m, n and k are each independently an integer satisfying p+m is greater than 1 and p+m+n+k=3, Y 1 When it is an oxygen atom, p, m, n and k are each independently an integer satisfying p+m is greater than 1 and p+m+n+k=2, When p is above 1, n is above 1, Z 1 are each independently a group represented by any one of the following formulae (T1) to (T14), In formula (2), Y 3 represents a carbon atom or a silicon atom, R 1 ~R 4 each independently represents a methyl group, a tert-butyl group or a tert-butoxy group, In formula (3), Z 2 It is a group represented by the following formula (T14).

[0016]

Chemical formula 10

[0017] In formulas (T1) to (T14), A 1 Each independently represents a hydrogen atom, a chlorine atom, a methyl group, a tert-butyl group, -OR, -NR2 or -SR, A 2 Each independently represents a chlorine atom, a methyl group, a tert-butyl group, -OR, -NR2 or -SR, each R independently represents a methyl group or a tert-butyl group, and * represents a bonding site.

[0018] There are multiple A in one group 1 In the case of multiple A 1They can be the same or different. 2 In the case of multiple A 2 They can be the same or different from each other.

[0019] By using the method for producing a fluorinated copolymer disclosed herein, it is possible to obtain a fluorinated copolymer by polymerization at a faster polymerization rate than conventional methods. The present inventors presume the following reasons for producing such an effect.

[0020] In the method for producing a fluorinated copolymer disclosed herein, polymerization is carried out in a polymerization medium containing a polymerization solvent A comprising at least one selected from the compounds represented by formula (1) to formula (3). The chain transfer properties of the polymerization solvent A are all low. Therefore, it is presumed that polymerization of the monomers containing tetrafluoroethylene proceeds smoothly.

[0021] The method for producing the fluorinated copolymer disclosed in the present invention will be described in detail below.

[0022] (Polymerization medium) The polymerization medium contains a polymerization solvent A which is at least one selected from the group consisting of compounds represented by formula (1) to formula (3).

[0023] <Compound represented by formula (1)>

Chemical formula 11

[0024] In formula (1), Y 1 represents a nitrogen atom or an oxygen atom. Y 1 When it is a nitrogen atom, p, m, n and k are each independently an integer satisfying p+m is greater than or equal to 1 and p+m+n+k=3. Y 1 When it is an oxygen atom, p, m, n and k are each independently an integer satisfying p+m is greater than or equal to 1 and p+m+n+k=2. When p is greater than 1, n is greater than 1. Z 1 Each independently represents a group represented by any one of formulae (T1) to (T14).

[0025] In formulas (T1) to (T14), A 1 Each independently represents a hydrogen atom, a chlorine atom, a methyl group, a tert-butyl group, -OR, -NR2 or -SR, A 2 Each independently represents a chlorine atom, a methyl group, a tert-butyl group, -OR, -NR2 or -SR, each R independently represents a methyl group or a tert-butyl group, and * represents a bonding site.

[0026]

Chemical formula 12

[0027] In formula (1), the following combinations of p, m, n and k are exemplified. Y 1 When is a nitrogen atom, (p, m, n, k) = (0, 1, 0, 2), (0, 1, 1, 1), (0, 1, 2, 0), (1, 0, 1, 1), (1, 0, 2, 0), (0, 2, 0, 1), (0, 2, 1, 0), (1, 1, 1, 0), (2, 0, 1, 0), (0, 3, 0, 0), Y 1 When is an oxygen atom, (p, m, n, k) = (0, 1, 0, 1), (0, 1, 1, 0), (1, 0, 1, 0), (0, 2, 0, 0).

[0028] From the viewpoint of increasing the polymerization rate and increasing the molecular weight, in formula (1), Y 1 An oxygen atom is preferred. Among them, as a combination of p, m, n and k, (p, m, n, k) is preferably (0, 1, 0, 1), (0, 1, 1, 0) or (1, 0, 1, 0).

[0029] When n is 1 or more, from the viewpoint of increasing the polymerization rate, Z 1 Each independently is a group represented by any one of formulae (T1) to (T14), preferably a group represented by any one of formulae (T1) to (T7), more preferably a group represented by any one of formulae (T1) to (T3), and even more preferably a group represented by formula (T1).

[0030] In formulas (T1) to (T14), A 1 Each independently represents a hydrogen atom, a chlorine atom, a methyl group, a tert-butyl group, -OR, -NR2 or -SR, A 2 Each independently represents a chlorine atom, a methyl group, a tert-butyl group, -OR, -NR2 or -SR, and R each independently represents a methyl group or a tert-butyl group. 1 Each independently represents a methyl group, a tert-butyl group, -OR or -NR2, A 2 Each independently represents a methyl group, a tert-butyl group, -OR or -NR2, and each R independently represents a methyl group or a tert-butyl group.

[0031] In the compound represented by formula (1), Z 1 , for example, the following compounds can be mentioned.

[0032]

Chemical formula 13

[0033] Specific examples of the compound represented by formula (1) are listed below, but the compound represented by formula (1) is not limited thereto.

[0034]

Chemical formula 14

[0035]

Chemical formula 15

[0036] <Compound represented by formula (2)> [Chemical formula 16]

[0037] In formula (2), Y 3 represents a carbon atom or a silicon atom. R 1 ~R 4 Each independently represents a methyl group, a tert-butyl group or a tert-butoxy group.

[0038] Specific examples of the compound represented by formula (2) are listed below, but the compound represented by formula (2) is not limited thereto.

[0039]

Chemical formula 17

[0040] From the viewpoint of increasing the polymerization rate and the molecular weight, in formula (2), Y 3 Preferred is a carbon atom.

[0041] In addition, from the viewpoint of increasing the polymerization rate and increasing the molecular weight, in formula (2), R 1 ~R 4 Preferred is methyl.

[0042] <Compound represented by formula (3)>

Chemical formula 18

[0043] In formula (3), Z 2 It is a group represented by the following formula (T14).

[0044]

Chemical formula 19

[0045] That is, the compound represented by formula (3) is acetonitrile.

[0046] In the polymerization solvent A, the compound equivalent to the compound represented by formula (1) and the compound represented by formula (2) is defined as the compound represented by formula (1). That is, the compound represented by formula (2) does not include the compound represented by formula (1).

[0047] For example, di-tert-butyl ether is equivalent to the compound represented by formula (1) and the compound represented by formula (2), but it is defined as the compound represented by formula (1). That is, di-tert-butyl ether is not included in the compound represented by formula (2).

[0048] The proportion of the polymerization solvent A in the polymerization medium is preferably 70 mol % or more, more preferably 95 mol % or more.

[0049] <Other polymerization solvents> In the method for producing a fluorinated copolymer of the present disclosure, the polymerization medium may contain other polymerization solvents than the polymerization solvent A.

[0050] As other polymerization solvents, for example, there can be listed: aromatic hydrocarbon solvents such as benzene, toluene, and xylene; sulfoxide solvents such as dimethyl sulfoxide (DMSO); ketone solvents such as acetone and 2-butanone (methyl ethyl ketone); ether solvents such as tetrahydrofuran (THF) and dioxane; ester solvents such as ethyl acetate; halogen solvents such as hexafluoroisopropanol, chloroform, 1H-perfluorohexane, 1H,1H,1H,2H,2H-perfluorooctane, 1,3-bis(trifluoromethyl)benzene, 1,4-bis(trifluoromethyl)benzene, benzotriazole, chlorobenzene, 1,2-dichlorobenzene, and water.

[0051] <Polymerization method> The polymerization in the method for producing the fluorinated copolymer disclosed herein may be solution polymerization or suspension polymerization. Solution polymerization refers to a method of carrying out polymerization in a state where the monomer is dissolved in a polymerization medium. Suspension polymerization refers to a method of carrying out polymerization in a state where the monomer is suspended in a polymerization medium containing water.

[0052] -Solution Polymerization- In the method for producing the fluorinated copolymer disclosed herein, it is preferred to carry out solution polymerization using the above-mentioned monomers in a polymerization medium. In the solution polymerization, the proportion of water in the polymerization medium is preferably less than 10% by volume.

[0053] In solution polymerization, the polymerization medium is not particularly limited as long as it is a polymerization solvent A containing at least one selected from the compounds represented by formula (1) to (3). Preferred embodiments of the compounds represented by formula (1) to (3) are the same as described above.

[0054] From the viewpoint of increasing the polymerization rate and increasing the molecular weight, in formula (1), Y 1 Preferred is an oxygen atom.

[0055] When n is 1 or more, from the viewpoint of increasing the polymerization rate, Z 1 Preferably, each independently is a group represented by any one of formulae (T1) to (T7), more preferably a group represented by any one of formulae (T1) to (T3), and still more preferably a group represented by formula (T1).

[0056] From the viewpoint of increasing the polymerization rate and the molecular weight, in formula (2), Y 3 Preferred is a carbon atom.

[0057] In addition, from the viewpoint of increasing the polymerization rate and increasing the molecular weight, in formula (2), R 1 ~R 4 Preferred is methyl.

[0058] In solution polymerization, the polymerization medium preferably does not contain other polymerization solvents, and preferably consists of the polymerization solvent A alone, from the viewpoint of increasing the polymerization rate.

[0059] -Suspension polymerization- In the method for producing the fluorinated copolymer disclosed herein, it is preferred to carry out suspension polymerization using the above-mentioned monomer in a polymerization medium comprising a polymerization solvent A which is immiscible with water and at least one compound selected from the group consisting of the compounds represented by formula (1) or (2), and water. In the suspension polymerization, the proportion of water in the polymerization medium is preferably 10% to 80% by volume.

[0060] In formula (1), Y 1 represents a nitrogen atom or an oxygen atom, Y 1 When it is a nitrogen atom, p, m, n and k are each independently an integer satisfying p+m is greater than 1 and p+m+n+k=3, Y 1 When it is an oxygen atom, k is 0, p, m and n are each independently an integer satisfying p+m is greater than 1 and p+m+n=2, When p is above 1, n is above 1, Z 1 are each independently a group represented by any one of the above formulae (T1) to (T3), (T7), (T8) and (T10), In formula (2), Y 3 represents a carbon atom or a silicon atom, R 1 ~R 4 each independently represents a methyl group, a tert-butyl group or a tert-butoxy group, In formula (T1) to formula (T3), formula (T7), formula (T8) and formula (T10), A 1 Each independently represents a hydrogen atom, a methyl group, a tert-butyl group, -OR or -NR2, A2 Each independently represents a methyl group, a tert-butyl group, -OR or -NR2, each R independently represents a methyl group or a tert-butyl group, and * represents a bonding site.

[0061] From the viewpoint of increasing the polymerization rate and increasing the molecular weight, in formula (1), Y 1 Preferred is an oxygen atom.

[0062] When n is 1 or more, from the viewpoint of increasing the polymerization rate, Z 1 Preferably, each independently is a group represented by any one of formulae (T1) to (T3), and more preferably is a group represented by formula (T1).

[0063] From the viewpoint of increasing the polymerization rate and the molecular weight, in formula (2), Y 3 Preferred is a carbon atom.

[0064] In addition, from the viewpoint of increasing the polymerization rate and increasing the molecular weight, in formula (2), R 1 ~R 4 Preferred is methyl.

[0065] In suspension polymerization, the polymerization medium preferably does not contain other polymerization solvents from the viewpoint of increasing the polymerization rate. In the polymerization medium, the proportion of polymerization solvent A and water is preferably 90 mol % or more, and more preferably consists of polymerization solvent A and water alone.

[0066] (monomers containing tetrafluoroethylene) In the method for producing a fluorinated copolymer disclosed herein, a monomer containing tetrafluoroethylene (hereinafter also referred to as "TFE") is polymerized. That is, the fluorinated copolymer obtained by the method for producing a fluorinated copolymer disclosed herein contains a structural unit derived from TFE. In addition, the fluorinated copolymer may be a homopolymer consisting only of TFE, that is, it may be polytetrafluoroethylene (PTFE).

[0067] In the present disclosure, "monomer" is a compound used for polymerization, and refers to a polymerizable compound having a polymerizable group. In addition, in the present disclosure, "monomer" refers to a compound having a number average molecular weight of 1000 or less, and is distinguished from oligomers and polymers.

[0068] The monomer used for polymerization can also include other monomers other than TFE. That is, the fluorinated copolymer can also include other structural units other than the structural unit from TFE. In addition, the other monomers other than TFE can be only one, or can be more than two.

[0069] Monomers other than TFE are not particularly limited as long as they have a polymerizable group.

[0070] The polymerizable group is preferably a radical polymerizable group, and more preferably an ethylenically unsaturated group. Examples of the ethylenically unsaturated group include a vinyl group, a vinyl ether group, a vinyl ester group, and a (meth)acryloyl group.

[0071] Examples of other monomers other than TFE include olefins, vinyl ethers, vinyl esters, vinyl amides, styrenes, maleimides, (meth)acrylates, (meth)acrylic acid, (meth)acrylamide, and (meth)acrylonitrile.

[0072] The monomer used for polymerization preferably further contains a fluorine-containing monomer having a fluorine atom other than TFE, and the fluorine-containing monomer preferably contains at least one selected from the group consisting of fluorine-containing monomers represented by the following formula (X1), formula (X2), and formula (X3).

[0073] CX 1 X 2 =C(X 3 )-(O) n1 -Rf 1 R 10 …(X1)

[0074]

Chemical formula 20

[0075]

Chemical formula 21

[0076] In formula (X1), X 1 , X 2 and X 3 each independently represents a hydrogen atom or a fluorine atom, R 1 represents a perfluoroalkylene group having 1 to 5 carbon atoms, wherein the perfluoroalkylene group may contain an ethereal oxygen atom between carbon-carbon bonds, R 10 Represents hydrogen atom, fluorine atom, -SO2R 11 、-COR 11 or cyano, R 11 each independently represents a hydrogen atom, a fluorine atom, a hydroxyl group or an alkoxy group, n1 is 0 or 1.

[0077] In formula (X2), X 4 and X 5 each independently represents a hydrogen atom or a fluorine atom, R 2 and Rf 3 Each independently represents a perfluoroalkyl group having 1 to 5 carbon atoms or a fluorine atom, and the perfluoroalkyl group may contain an ethereal oxygen atom between carbon-carbon bonds.

[0078] In formula (X3), X 6 , X 8 and X 9 each independently represents a hydrogen atom or a fluorine atom, X 7 each independently represents a hydrogen atom, a fluorine atom or a trifluoromethyl group, R 20 Each independently represents a fluorine atom or -Rf 4 -R 30 , R 40 Each independently represents a fluorine atom or -Rf 5 -R 50 , R 4 and Rf 5 Each independently represents a perfluoroalkylene group having 1 to 5 carbon atoms, wherein the perfluoroalkylene group may contain an ethereal oxygen atom between carbon-carbon bonds, R 30 and R 50 Respectively independently represent -SO2R 11 、-COR 11 or cyano.

[0079] <Fluorine-containing monomer represented by formula (X1)> In formula (X1), Rf 1 The perfluoroalkylene group represented preferably has 1 to 3 carbon atoms. From the perspective of the chemical stability of monomers and polymers, R 10 Preferred is a hydrogen atom or a fluorine atom.

[0080] In the formula (X1), examples of the compound wherein n1 is 1 include perfluoro(alkyl vinyl ether) (hereinafter also referred to as "PAVE").

[0081] As PAVE, for example, CF2=CFOCF3 (hereinafter also referred to as "PMVE"), CF2=CFOCF2CF3, CF2=CFOCF2CF2CF3 (hereinafter also referred to as "PPVE"), CF2=CFOCF2CF2CF2CF3, and CF2=CFO(CF2)8F can be listed.

[0082] Among them, PAVE is preferably PMVE or PPVE.

[0083] In the formula (X1), examples of the compound in which n1 is 0 include hexafluoropropylene (hereinafter also referred to as "HFP") and fluoroalkylethylene (hereinafter also referred to as "FAE").

[0084] 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.

[0085] Among them, FAE is preferably PFEE or PFBE.

[0086] <Fluorine-containing monomer represented by formula (X2)> In formula (X2), Rf 2 and Rf 3 The carbon number of the perfluoroalkyl group represented is preferably 1 to 3 respectively and independently.

[0087] Examples of the fluorine-containing monomer represented by the formula (2) include the following compounds.

[0088]

Chemical formula 22

[0089] <Fluorine-containing monomer represented by formula (X3)> In formula (X3), Rf 4 and Rf 5 The carbon number of the perfluoroalkylene group represented is preferably 1 to

[0090] Examples of the fluorine-containing monomer represented by the formula (3) include the following compounds.

[0091]

Chemical formula 23

[0092] <Other fluorinated monomers> The monomers used for polymerization may further contain other fluorine-containing monomers in addition to the fluorine-containing monomers represented by the above formula (X1), formula (X2), and formula (X3).

[0093] Examples of other fluorine-containing monomers include: Fluoroolefins such as vinylidene fluoride, vinyl fluoride, trifluoroethylene, and hexafluoroisobutylene; A fluorinated monomer having two ethylenically unsaturated groups such as CF2=CFOCF2CF=CF2 and CF2=CFO(CF2)2CF=CF2.

[0094] When vinylidene fluoride is contained as another fluorine-containing monomer, the content of vinylidene fluoride is preferably 1 mol % to 50 mol % based on the total amount of monomers used for polymerization.

[0095] Among them, the monomers used for polymerization preferably further contain at least one fluorine-containing monomer selected from HFP and PAVE.

[0096] That is, the fluorinated copolymer obtained by the method for producing a fluorinated copolymer of the present disclosure is preferably a copolymer comprising a structural unit derived from TFE and at least one selected from a structural unit derived from HFP and a structural unit derived from PAVE.

[0097] As a preferred embodiment, a copolymer including a structural unit derived from TFE and a structural unit derived from HFP can be mentioned. This copolymer is called "FEP".

[0098] Furthermore, as another preferred embodiment, a copolymer including a structural unit derived from TFE and a structural unit derived from PAVE can be cited. This copolymer is called "PFA" or "FFKM".

[0099] The content of the structural unit derived from TFE in PFA is preferably 80 to 99.9 mol %, more preferably 90 to 99.5 mol %, further preferably 95 to 99 mol %, based on all the structural units of the obtained fluorinated copolymer. In FFKM, the content of the structural unit derived from TFE is preferably from 30 to 80 mol %, more preferably from 50 to 78 mol %, based on all the structural units of the obtained fluorinated copolymer.

[0100] In FEP, the content of the structural unit derived from HFP is preferably at most 40 mol %, more preferably at most 30 mol %, further preferably at most 20 mol %, based on all the structural units of the obtained fluorinated copolymer. The content of the structural unit derived from PAVE in PFA is preferably 0.1 to 20 mol %, more preferably 0.5 to 10 mol %, further preferably 1 to 5 mol %, based on all the structural units of the obtained fluorinated copolymer. In FFKM, the content of the structural unit derived from PAVE is preferably from 20 to 70 mol %, more preferably from 22 to 50 mol %, based on all the structural units of the obtained fluorinated copolymer.

[0101] <Non-fluorinated monomer> The monomer used for polymerization may further include a monomer having no fluorine atom (hereinafter also referred to as "non-fluorine monomer").

[0102] The non-fluorine-containing monomer is not particularly limited as long as it has no fluorine atom and has a polymerizable group.

[0103] The polymerizable group is preferably a radical polymerizable group, and more preferably an ethylenically unsaturated group. Examples of the ethylenically unsaturated group include a vinyl group, a vinyl ether group, a vinyl ester group, and a (meth)acryloyl group.

[0104] Examples of the non-fluorine monomer include compounds having no fluorine atom among olefins, vinyl ethers, vinyl esters, vinyl amides, styrenes, maleimides, (meth)acrylates, (meth)acrylic acid, (meth)acrylamide and (meth)acrylonitrile.

[0105] Among them, from the viewpoint of the polymerization rate and copolymerizability with the fluorine-containing monomer, the monomer used for polymerization preferably further contains a non-fluorine monomer having no fluorine atom and having an ethylenically unsaturated group.

[0106] Furthermore, from the viewpoint of solubility, the monomer used for polymerization preferably further contains a non-fluorine monomer having no fluorine atom, an ethylenically unsaturated group, and a reactive group.

[0107] The reactive group is preferably at least one selected from a reactive silyl group, an amino group, an isocyanate group, a hydroxyl group, an epoxy group, an acid anhydride residue, an alkoxycarbonyl group, a carboxyl group and a carbonyl group, and more preferably at least one selected from a hydroxyl group, an acid anhydride residue, an alkoxycarbonyl group, a carboxyl group and a carbonyl group.

[0108] In the case where the monomer used for polymerization contains a non-fluorine monomer having no fluorine atom, having an ethylenically unsaturated group and having a reactive group, the polymerization medium preferably contains no water.

[0109] The reactive silyl group is a group in which a reactive group is bonded to a silicon atom (Si atom). As the reactive group, a hydrolyzable group or a hydroxyl group is preferred.

[0110] The hydrolyzable group is a group that is converted into a hydroxyl group by a hydrolysis reaction. That is, the hydrolyzable silyl group represented by Si-L is converted into a silanol group represented by Si-OH by a hydrolysis reaction. Examples of the hydrolyzable group include an alkoxy group, an aryloxy group, a halogen atom, an acyl group, an acyloxy group, and an isocyanate group (-NCO). As the alkoxy group, an alkoxy group having 1 to 4 carbon atoms is preferred. The aryl group of the aryloxy group includes a heteroaryl group. The halogen atom is preferably a chlorine atom. The acyl group is preferably an acyl group having 1 to 6 carbon atoms. The acyloxy group is preferably an acyloxy group having 1 to 6 carbon atoms.

[0111] As the reactive silyl group, a group represented by the following formula (A) is preferred.

[0112] -Si(R A ) w L 3-w …(A) R A Each of them is independently a hydrocarbon group, each of L is independently a hydrolyzable group or a hydroxyl group, and n is an integer of 0-2.

[0113] When there are a plurality of reactive silyl groups in one molecule, the plurality of reactive silyl groups may be the same or different from each other. From the viewpoint of the ease of purchasing the raw materials and the ease of producing the compound, the plurality of reactive silyl groups are preferably the same.

[0114] R A R are independently a hydrocarbon group, preferably a saturated hydrocarbon group. A The carbon number of alkylene oxide is preferably 1-6, more preferably 1-3, and further preferably 1-2.

[0115] As the hydrolyzable group, those described above are preferred.

[0116] Among them, from the viewpoint of easy production of the compound, L is preferably an alkoxy group having 1 to 4 carbon atoms or a halogen atom. From the viewpoint of better storage stability of the compound, L is preferably an alkoxy group having 1 to 4 carbon atoms, and more preferably an ethoxy group or a methoxy group.

[0117] w is an integer of 0 to 2, preferably 0 or 1, and more preferably 0. When w is 1 or less, the multiple L present in one molecule may be the same or different from each other. From the viewpoint of the ease of purchasing the raw materials and the ease of manufacturing the compound, the multiple L are preferably the same. When w is 2, the multiple R present in one molecule may be the same or different from each other. A From the perspective of ease of purchasing raw materials and ease of manufacturing compounds, multiple R A Preferably the same.

[0118] Examples of the monomer having a reactive silyl group include vinyltrimethoxysilane, vinyltriethoxysilane, p-styryltrimethoxysilane, 2-methacryloxyethyltrimethoxysilane, 2-methacryloxyethyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 4-methacryloxybutyltrimethoxysilane, 4-methacryloxybutyltriethoxysilane, 2-acryloxyethyltrimethoxysilane, 2-acryloxyethyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, 4-acryloxybutyltrimethoxysilane, and 4-acryloxybutyltriethoxysilane.

[0119] Examples of the monomer having an amino group include: (meth)acrylates having an amino group such as N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, 1-(N,N-dimethylamino)-1,1-dimethylmethyl (meth)acrylate, N,N-dimethylaminohexyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, N,N-diisopropylaminoethyl (meth)acrylate, N,N-di-n-butylaminoethyl (meth)acrylate, N,N-diisobutylaminoethyl (meth)acrylate, morpholinylethyl (meth)acrylate, piperidinylethyl (meth)acrylate, 1-pyrrolidinylethyl (meth)acrylate, N,N-methyl-2-pyrrolidinylaminoethyl (meth)acrylate, N,N-methylphenylaminoethyl (meth)acrylate, and tert-butylaminoethyl (meth)acrylate; (Meth)acrylamide having an amino group, such as 2-(N,N-dimethylamino)ethyl(meth)acrylamide, 2-(N,N-diethylamino)ethyl(meth)acrylamide, 3-(N,N-diethylamino)propyl(meth)acrylamide, 3-(N,N-dimethylamino)propyl(meth)acrylamide, 1-(N,N-dimethylamino)-1,1-dimethylmethyl(meth)acrylamide, and 6-(N,N-diethylamino)hexyl(meth)acrylamide.

[0120] Examples of the monomer having an isocyanate group include 2-isocyanateethyl (meth)acrylate, 3-isocyanatepropyl (meth)acrylate, 4-isocyanatebutyl (meth)acrylate, and 2-(2-methacryloyloxyethyloxy)ethyl isocyanate.

[0121] The above-mentioned monomer having an isocyanate group may be blocked with a blocking agent. Examples of the blocking agent include pyrazoles such as 3,5-dimethylpyrazole, oximes such as 2-butanone oxime, and lactams such as ε-caprolactam.

[0122] Examples of the monomer having a hydroxyl group include (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; Vinyl ethers such as hydroxyethyl vinyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinyl ether; and Allyl ethers such as hydroxyethyl allyl ether, hydroxypropyl allyl ether and hydroxybutyl allyl ether.

[0123] As a monomer which has an epoxy group, glycidyl (meth)acrylate is mentioned, for example.

[0124] Examples of the monomer having an acid anhydride residue include itaconic anhydride, citraconic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, and maleic anhydride.

[0125] Examples of the monomer having an alkoxycarbonyl group include methyl (meth)acrylate, butyl acrylate, and methyl 3-butenoate.

[0126] Examples of the polymerizable monomer having a carboxyl group include (meth)acrylic acid, itaconic acid, 2-(meth)acryloyloxyethylsuccinic acid, and 2-(meth)acryloyloxyhexahydrophthalic acid.

[0127] Examples of the monomer having a carbonyl group include vinyl methyl ketone, allyl methyl ketone, and vinyl acetate.

[0128] In the method for producing a fluorinated copolymer disclosed herein, the content of the structural unit derived from TFE is preferably at least 30 mol %, more preferably at least 40 mol %, further preferably at least 50 mol %, based on all the structural units of the obtained fluorinated copolymer.

[0129] The content of the structural units derived from monomers other than TFE is preferably at most 70 mol %, more preferably at most 60 mol %, further preferably at most 50 mol %, based on all the structural units of the obtained fluorinated copolymer.

[0130] In a preferred embodiment, the monomers used for polymerization further include at least one fluorine-containing monomer selected from HFP and PAVE, and a non-fluorine-containing monomer having no fluorine atom, an ethylenically unsaturated group and an acid anhydride residue.

[0131] In the above embodiment, the content of the structural unit derived from TFE is preferably at least 30 mol %, more preferably at least 40 mol %, further preferably at least 50 mol %, based on all the structural units of the obtained fluorinated copolymer.

[0132] In the above embodiment, the content of the structural unit derived from at least one fluorinated monomer selected from HFP and PAVE is preferably 1 to 30 mol %, more preferably 2 to 20 mol %, further preferably 3 to 15 mol % based on all the structural units of the obtained fluorinated copolymer.

[0133] In the above embodiment, the content of the structural unit derived from the non-fluorinated monomer having no fluorine atom, an ethylenically unsaturated group and an acid anhydride residue is preferably 1 to 20 mol %, more preferably 1 to 15 mol %, further preferably 1 to 10 mol % based on all the structural units of the obtained fluorinated copolymer.

[0134] In the method for producing a fluorinated copolymer disclosed herein, the content of TFE is preferably at least 10 mol %, more preferably at least 15 mol %, based on the total amount of monomers used for polymerization.

[0135] The content of monomers other than TFE is preferably 90 mol % or less, more preferably 85 mol % or less, based on the total amount of monomers used for polymerization.

[0136] In a preferred embodiment, the monomers used for polymerization further include at least one fluorine-containing monomer selected from HFP and PAVE.

[0137] When PAVE is contained and PFA is polymerized, the content of TFE is preferably 70 mol % or more, more preferably 80 mol % or more, based on the total amount of monomers used for polymerization. When PAVE is included and FFKM is polymerized, the content of TFE is preferably 10 mol % or more, more preferably 20 mol % or more, based on the total amount of monomers used for polymerization. When HFP is contained, the content of TFE is preferably 10 mol % or more, more preferably 20 mol % or more, based on the total amount of monomers used for polymerization.

[0138] When PAVE is contained and PFA is polymerized, the content of PAVE is preferably 30 mol% or less, more preferably 20 mol% or less, based on the total amount of monomers used for polymerization. When PAVE is contained and FFKM is polymerized, the content of PAVE is preferably 90 mol % or less, more preferably 80 mol % or less, based on the total amount of monomers used for polymerization. When HFP is contained, the content of HFP is preferably 90 mol % or less, more preferably 80 mol % or less, based on the total amount of monomers used for polymerization.

[0139] (Polymerization initiator) In the method for producing the fluorinated copolymer disclosed herein, it is preferred to use a polymerization initiator in order to start the polymerization reaction.

[0140] The polymerization initiator is preferably a free radical polymerization initiator. Examples of the free radical polymerization initiator include azo compounds such as azobisisobutyronitrile and 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile); peroxydicarbonates such as diisopropyl peroxydicarbonate; peroxyesters such as tert-butyl peroxypivalate, tert-butyl peroxyisobutyrate, and tert-butyl peroxyacetate; non-fluorinated diacyl peroxides such as diisobutyryl peroxide, dioctanoyl peroxide, benzoyl peroxide, and lauroyl peroxide; (Z(CF2) pCOO)2 (Z is a hydrogen atom, a fluorine atom or a chlorine atom, and p is an integer from 1 to 10); perfluoro tert-butyl peroxide; and inorganic peroxides such as potassium persulfate, sodium persulfate, and ammonium persulfate.

[0141] (Chain transfer agent) The method for producing the fluorinated copolymer disclosed herein can be carried out by performing the polymerization reaction in the presence of a chain transfer agent. The presence of the chain transfer agent makes it easy to adjust the molecular weight of the produced fluorinated copolymer.

[0142] Examples of the chain transfer agent include alcohols such as methanol, ethanol, 2,2,2-trifluoroethanol, 2,2,3,3-tetrafluoropropanol, 1,1,1,3,3,3-hexafluoroisopropanol, and 2,2,3,3,3-pentafluoropropanol; hydrocarbons such as n-pentane, n-hexane, and cyclohexane; hydrofluorocarbons such as CF2H2; ketones such as acetone; thiols such as methyl mercaptan; esters such as methyl acetate and ethyl acetate; and ethers such as diethyl ether and methyl ethyl ether.

[0143] (Aggregate form) In the method for producing a fluorinated copolymer disclosed herein, for example, a monomer containing TFE is continuously or intermittently added to a polymerization medium to carry out a polymerization reaction. In the method for producing a fluorinated copolymer disclosed herein, it is preferred that there is only one reaction step.

[0144] For example, in the case of obtaining a block copolymer, a polymerization reaction is carried out using only the first monomer among the monomers used for polymerization (first step), and after the reaction of the first step is completed, a second monomer is added to carry out a polymerization reaction (second step), thereby generating a structure in which a first block derived from the first monomer and a second block derived from the second monomer are connected.

[0145] On the other hand, in the case of obtaining a random copolymer, a single polymerization reaction is carried out with all the monomers used for polymerization, thereby generating a structure in which the structural units from the monomers used for polymerization are randomly arranged. In addition, the monomers used for polymerization can be added to the polymerization medium before the polymerization reaction ends, and it is not necessary to add all at once.

[0146] (Polymerization conditions) In the method for producing the fluorinated copolymer of the present disclosure, at any stage of the polymerization, the amount (mol) of the polymerization solvent A is denoted as M sol The solubility of TFE in the polymerization solvent A (mol / mol) is recorded as S, and the amount of TFE dissolved in the polymerization medium (mol) is recorded as M mon When 0.5≤M sol ×S / M mon ≤1.0.

[0147] In the present disclosure, "during polymerization" means a period during which a fluorinated copolymer containing TFE is produced.

[0148] When the polymerization medium is composed of only the polymerization solvent A and does not contain any polymerization medium other than the polymerization solvent A, M sol ×S / M mon When the polymerization medium contains a polymerization medium other than the polymerization solvent A, M sol ×S / M mon Less than 1.0.

[0149] If M sol ×S / M mon When M is 0.5 to 1.0, chain transfer caused by the polymerization medium is suppressed and the polymerization rate is increased. sol ×S / M mon It is more preferably 0.7 to 1.0, and even more preferably 0.85 to 1.0.

[0150] <Amount M of polymerization solvent A sol > M represents the amount of substance of the polymerization solvent A sol Calculate using the following formula. M sol (mol) = weight of polymerization solvent A (g) / molecular weight of polymerization solvent A The weight of the polymerization solvent A is a value measured under atmospheric pressure.

[0151] <Solubility S of TFE in polymerization solvent A> The solubility S of TFE in the polymerization solvent A is calculated by the following method. First, the vapor pressure P of the polymerization solvent A is measured. sol .P sol The pressure indicated is when the polymerization medium is placed in a stainless steel autoclave equipped with a stirrer, subjected to freeze degassing twice, and the internal temperature of the reactor is maintained at a predetermined temperature T. T represents the liquid phase temperature. The temperature of the gas phase is set equal to the liquid phase temperature. The weighed polymerization solvent A is placed in a stainless steel autoclave equipped with a stirrer. The amount M' (mol) of the polymerization solvent A is calculated from the weighed weight (g). Then, the weighed TFE gas was added into a stainless steel autoclave equipped with a stirrer. all (mol) is calculated using the weighed gas weight W (g) by the following formula. M all =W / 100 When the pressure becomes constant after a sufficiently long time, it is the total pressure P.all . Partial pressure of TFE gas P mon It is calculated by the following formula. P mon =P all -P sol The volume V of the gas phase portion of the stainless steel autoclave equipped with a stirrer was calculated by the following formula. V = Volume of stainless steel autoclave with stirrer - Volume of polymerization solvent A The amount of TFE gas present in the gas phase of the stainless steel autoclave with a stirrer M g (mol) is calculated by the following formula: Wherein, R represents the gas constant. M g =P mon V / RT The amount of TFE gas dissolved in the polymerization solvent A is M' mon (mol) is calculated by the following formula. M' mon =M all -M g The solubility S of TFE in the polymerization solvent A is calculated by the following formula. S=M' mon / M'

[0152] <The amount of TFE dissolved in the polymerization medium M mon > The amount of TFE dissolved in the polymerization medium M mon It is calculated by the following formula. First, the vapor pressure P' of the polymerization solvent is measured. sol . P' sol The pressure indicated is when the polymerization medium is placed in a stainless steel autoclave equipped with a stirrer, subjected to freeze degassing twice, and the internal temperature of the reactor is maintained at a predetermined temperature T. T represents the liquid phase temperature. The temperature of the gas phase is set equal to the liquid phase temperature. Then, the weighed TFE gas was added into a stainless steel autoclave equipped with a stirrer. The amount of TFE gas added was M' all (mol) is calculated using the weighed gas weight W' (g) by the following formula. M' all =W' / 100 When the pressure becomes constant after a sufficiently long time, it is the total pressure P' all . Partial pressure of gas mixed with TFE P' mon It is calculated by the following formula. P'mon =P' all -P' sol The volume V' of the gas phase portion of the stainless steel autoclave equipped with a stirrer was calculated by the following formula. V' = Volume of stainless steel autoclave with stirrer - Volume of polymerization solvent The amount of the mixed gas mixed with TFE in the gas phase of the stainless steel autoclave with a stirrer M' g (mol) is calculated by the following formula: Wherein, R represents the gas constant. M' g =P' mon ×V' / RT The amount of TFE gas dissolved in the polymerization solvent M mon (mol) is calculated by the following formula. M mon =M' all -M' g

[0153] In the method for producing the fluorinated copolymer disclosed herein, the polymerization temperature is preferably 0 to 100° C., more preferably 20 to 90° C. The polymerization pressure is preferably 0.1 to 10 MPaG, more preferably 0.5 to 3 MPaG. The polymerization time is preferably 1 to 30 hours, more preferably 2 to 20 hours.

[0154] [Fluorinated copolymer] The fluorine-containing copolymer disclosed in the present invention includes a structural unit derived from TFE.

[0155] The fluorinated copolymer of the present disclosure may further contain other structural units other than the structural unit derived from TFE. Example

[0156] The present disclosure is described in more detail below through examples, but the present disclosure is not limited to the following examples within the scope of the technical concept thereof.

[0157] [Example 1] A stainless steel autoclave with a stirrer and an internal volume of 600 mL was immersed in an ice water bath and kept for 10 minutes, and then 360 mL (4.3 mol) of dimethyl carbonate (referred to as "DMC" in the table) was added as a polymerization medium and freeze-degassed twice. The internal temperature of the reactor was raised to 30°C while stirring, and CF2=CFOCF2CF2CF3 (PPVE) and TFE (TFE:PPVE (molar ratio) = 84:16) were injected as monomers so that the internal pressure of the reactor reached 2.0 MPaG. 22 mg (0.13 mmol) of diisobutyryl peroxide (trade name "PEROYL IB", manufactured by NOF Corporation, "IBPO" in the table) was further injected as a polymerization initiator, and the internal temperature was maintained at 30°C while stirring at 200 rpm (200 revolutions per minute) for 3 hours. In this way, a polymer solution containing a copolymer of TFE and PPVE was obtained. After the reactor was cooled to room temperature, unreacted TFE and PPVE were discharged. The obtained polymer solution was added to methanol, and the precipitate was separated by filtration. The precipitate was dried in a vacuum oven at 40° C. for 12 hours. 73 g of a copolymer of TFE and PPVE was obtained. TFE unit:PPVE unit=97:3 (molar ratio). Among them, dimethyl carbonate corresponds to the compound represented by formula (1), wherein Y 1 is an oxygen atom, p is 1, m is 0, n is 1, k is 0, Z 1 is a group represented by formula (T1), wherein A 1 is -OR, and R is methyl.

[0158] [Example 2] 44 g of a copolymer of TFE and PPVE was obtained by the same method as in Example 1 except that the polymerization initiator was changed to 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) (trade name "V70", manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., "AMVN" in the table) and the polymerization temperature was changed to 35° C. TFE unit:PPVE unit=98:2 (molar ratio).

[0159] [Example 3] 55 g of a copolymer of TFE and PPVE was obtained by the same method as in Example 1 except that the polymerization initiator was changed to tert-butyl peroxypivalate (trade name "Perbutyl PV", manufactured by NOF Corporation, "PBPV" in the table) and the polymerization temperature was changed to 66° C. TFE unit:PPVE unit=98:2 (molar ratio).

[0160] [Example 4] 26 g of a copolymer of TFE and PPVE was obtained by the same method as in Example 1 except that the polymerization medium was changed to tert-butylamine ("TBA" in the table). TFE unit:PPVE unit=98:2 (molar ratio). Among them, tert-butylamine is equivalent to the compound represented by formula (1), in which Y1 is a nitrogen atom, p is 0, m is 1, n is 0, and k is 2.

[0161] [Example 5~Example 7] A copolymer of TFE and HFP was obtained by the same method as in Examples 1 to 3 except that TFE and HFP (TFE:HFP (molar ratio) = 15:85) were used as monomers. In Example 5, 142 g of a copolymer (TFE unit:HFP unit=89:11 (molar ratio)) was obtained. In Example 6, 78 g of a copolymer (TFE unit:HFP unit=90:10 (molar ratio)) was obtained. In Example 7, 99 g of a copolymer (TFE unit:HFP unit=91:9 (molar ratio)) was obtained.

[0162] [Example 8] 81 g of a copolymer of TFE and PMVE was obtained by the same method as in Example 1 except that TFE and CF2=CFOCF3(PMVE) (TFE:PMVE (molar ratio) = 25:75) were used as monomers. TFE unit:PMVE unit = 78:22 (molar ratio).

[0163] [Example 9] 73 g of PTFE was obtained by the same method as in Example 1 except that only TFE was used as the monomer.

[0164] [Example 10] 25 g of PTFE was obtained by the same method as in Example 4 except that only TFE was used as the monomer.

[0165] [Example 11] 40 g of a copolymer of TFE, PPVE and maleic anhydride was obtained by the same method as in Example 1 except that TFE gas, CF2=CFOCF2CF2CF3 (PPVE) and maleic anhydride (TFE:PPVE:maleic anhydride (molar ratio)=83:15:2) were used as monomers. TFE unit:PPVE unit:maleic anhydride unit=95:2:3 (molar ratio).

[0166] [Example 12] 57 g of a copolymer of TFE, PPVE and maleic anhydride was obtained by the same method as in Example 1 except that TFE, HFP and maleic anhydride (TFE:HFP:maleic anhydride (molar ratio) = 14:84:2) were used as monomers. TFE unit:PPVE unit:maleic anhydride unit = 88:9:3 (molar ratio).

[0167] [Example 13] 6.5 g of a copolymer of TFE and PPVE was obtained by the same method as in Example 1, except that the polymerization medium was changed to di-tert-butyl carbonate ("Boc2O" in the table), the polymerization initiator was changed to diisopropyl peroxydicarbonate (trade name "PEROYL IPP", manufactured by NOF Corporation, "IPP" in the table), and the polymerization temperature was changed to 45°C. TFE unit:PPVE unit=97:3 (molar ratio). Among them, di-tert-butyl carbonate is equivalent to the compound represented by formula (1), in which Y 1 is an oxygen atom, p is 0, m is 1, n is 1, k is 0, Z 1 is a group represented by formula (T1), wherein A 1 is -OR, and R is tert-butyl.

[0168] [Example 14] 13 g of a copolymer of TFE and PPVE was obtained in the same manner as in Example 1 except that the polymerization medium was changed to neopentane and the polymerization temperature was changed to 20° C. TFE unit:PPVE unit=98:2 (molar ratio). Among them, neopentane corresponds to the compound represented by formula (2), in which Y 3 is a carbon atom, R 1 ~R 4 It is methyl.

[0169] [Example 15] 11 g of a copolymer of TFE and HFP was obtained by the same method as in Example 5 except that the polymerization medium was changed to methyl pivalate ("MePiv" in the table). TFE unit:HFP unit=91:9 (molar ratio). Among them, methyl pivalate is equivalent to the compound represented by formula (1), in which Y 1 is an oxygen atom, p is 1, m is 0, n is 1, k is 0, Z 1 is a group represented by formula (1), wherein A 1 It is tert-butyl.

[0170] [Example 16] 24 g of a copolymer of TFE and HFP was obtained by the same method as in Example 5 except that the polymerization medium was changed to trimethyl phosphate ("TMP" in the table). TFE unit:HFP unit=89:11 (molar ratio). Among them, trimethyl phosphate corresponds to the compound represented by formula (1), wherein Y 1 is an oxygen atom, p is 1, m is 0, n is 1, k is 0, Z 1 is a group represented by formula (T3), wherein A 2is -OR, and R is methyl.

[0171] [Example 17] 44 g of a copolymer of TFE and HFP was obtained in the same manner as in Example 5 except that the polymerization medium was changed to tetramethylsilane ("TMS" in the table) and the polymerization temperature was changed to 25°C. TFE unit:HFP unit=90:10 (molar ratio). Among them, tetramethylsilane is equivalent to the compound represented by formula (2), in which Y 3 is a silicon atom, R 1 ~R 4 It is methyl.

[0172] [Example 18] 38 g of a copolymer of TFE and PPVE was obtained by the same method as in Example 1, except that the polymerization medium was changed to a mixture of dimethyl carbonate and methyl ethyl ketone ("MEK" in the table) (dimethyl carbonate:MEK (molar ratio) = 85:15) ("DMC / MEK = 85 / 15" in the table). TFE unit:PPVE unit = 97:3 (molar ratio).

[0173] [Example 19] 15 g of a copolymer of TFE and PPVE was obtained by the same method as in Example 1 except that the polymerization medium was changed to a mixture of dimethyl carbonate and MEK (dimethyl carbonate:MEK (molar ratio) = 70:30) ("DMC / MEK = 70 / 30" in the table). TFE unit:PPVE unit = 98:2 (molar ratio).

[0174] [Example 20] 43 g of a copolymer of TFE and PPVE was obtained by the same method as in Example 1 except that the polymerization medium was changed to a mixture of methyl pivalate and dimethyl carbonate (methyl pivalate: dimethyl carbonate (molar ratio) = 50:50) ("MePiv / DMC = 50 / 50" in the table). TFE unit:PPVE unit = 97:3 (molar ratio).

[0175] [Example 21] A copolymer of TFE and PPVE was attempted to be obtained by the same method as in Example 1 except that the polymerization medium was changed to tert-butyl methyl ether ("TBME" in the table). However, no copolymer was obtained. Tert-butyl methyl ether does not belong to the polymerization solvent A.

[0176] [Example 22] A copolymer of TFE, PPVE and norbornene anhydride was obtained by the same method as in Example 1, except that TFE, PPVE and norbornene anhydride (TFE:PPVE:norbornene anhydride (molar ratio) = 83:15:2) were used as monomers and 1H-perfluorohexane ("C6H" in the table) was used as the polymerization medium. However, although a copolymer was obtained, the introduction of anhydride groups could not be confirmed by IR measurement. 1H-perfluorohexane does not belong to polymerization solvent A.

[0177] [Example 23] A copolymer of TFE, HFP and norbornene anhydride was obtained by the same method as in Example 1, except that a mixed gas of TFE, HFP and norbornene anhydride (TFE:HFP:norbornene anhydride (molar ratio) = 14:84:2) was used as the monomer and the polymerization medium was changed to 1H-perfluorohexane. However, although a copolymer was obtained, the introduction of anhydride groups could not be confirmed by IR measurement. 1H-perfluorohexane does not belong to polymerization solvent A.

[0178] [Example 24] 16 g of a copolymer of TFE and PPVE was obtained in the same manner as in Example 1 except that the polymerization medium was changed to a mixture of dimethyl carbonate and water (water content: 20 vol%) ("DMC / water" in the table). TFE unit:PPVE unit=97:3 (molar ratio).

[0179] [Example 25] 28 g of a copolymer of TFE and HFP was obtained in the same manner as in Example 5 except that the polymerization medium was changed to a mixture of dimethyl carbonate and water (water content: 20 vol%) ("DMC / water" in the table). TFE unit:HFP unit=89:11 (molar ratio).

[0180] The polymerization rate in the production method of Examples 1 to 25 and the melt flow rate (MFR value) of the copolymer obtained in Examples 1 to 25 were measured. In Example 8, the storage modulus was measured instead of the MFR value. In addition, during the polymerization, the amount (mol) of the polymerization solvent A was recorded as M sol The solubility of TFE in the polymerization solvent A (mol / mol) is recorded as S, and the amount of TFE dissolved in the polymerization medium (mol) is recorded as M mon When M sol ×S / M mon The measurement method and calculation method are as follows. In addition, those that cannot be measured are marked as "-" in the table.

[0181] <Polymerization speed> The polymerization rate was calculated by the following formula. Polymerization rate (g / h·L) = yield of copolymer obtained (g) / {polymerization time (h)·volume of polymerization solvent (L)} The polymerization solvent mentioned here does not include a polymerization initiator.

[0182] <MFR value> The mass (g) of the copolymer flowing out from an orifice having a diameter of 2.095 mm and a length of 8.000 mm under the conditions of temperature: 372°C and load: 49.0 N in 10 minutes was measured using a thermal flow evaluation apparatus (trade name: "Flow Tester CFT-100EX", manufactured by Shimadzu Corporation) in accordance with ASTM D3159 and was determined as MFR (g / 10 minutes).

[0183] <Storage modulus G'> The value at 50 cpm was measured under the conditions of temperature: 100° C., strain 7% according to ASTM D6204.

[0184] <SSG> The measurement was carried out in accordance with ASTM D1457:91a and ASTM D4895:91a.

[0185] <Ratio of each monomer> The ratio of each structural unit in the polymer is determined by 19 It can be obtained by F-NMR analysis, fluorine content analysis or infrared absorption spectrum analysis.

[0186] <M sol ×S / M mon > First, as described above, the mass (mol) M of the polymerization solvent A is calculated. sol , the solubility of TFE in the polymerization solvent A (mol / mol) S and the amount of TFE dissolved in the polymerization medium (mol) M mon . Afterwards, use M sol , S and M mon Calculate M sol ×S / M mon .

[0187] Table 1 records the types of monomers, polymerization medium and polymerization initiator, as well as the polymerization rate, MFR (storage modulus in Example 8, SSG in Examples 9 and 10) and M sol ×S / M mon .

[0188] [Table 1]

[0189] As shown in Table 1, it can be seen that in Examples 1 to 20 and Examples 24 to 25, since polymerization is carried out using a monomer containing TFE in a polymerization medium containing a polymerization solvent A containing at least one compound selected from the compounds represented by formula (1) to formula (3), the polymerization rate is faster than before.

[0190] In addition, the entire contents of the disclosure of Japanese Patent Application No. 2022-112714 filed on July 13, 2022 are incorporated herein by reference. In addition, all documents, patent applications, and technical standards described in this specification are incorporated herein by reference to the same extent as if the portions incorporated by reference in each document, patent application, and technical standard were specifically and separately described.

Claims

1. A method for producing a fluorinated copolymer, In a polymerization medium containing a polymerization solvent A of at least one selected from the group consisting of compounds represented by the following formulae (1) to (3), polymerizing with monomers comprising tetrafluoroethylene; 【Chemical formula 1】 【Chemical formula 2】 【Chemical formula 3】 CH3-Z 2 (3) In formula (1), Y 1 represents a nitrogen atom or an oxygen atom, Y 1 When it is a nitrogen atom, p, m, n and k are each independently an integer satisfying p+m is greater than 1 and p+m+n+k=3, Y 1 When it is an oxygen atom, p, m, n and k are each independently an integer satisfying p+m is greater than 1 and p+m+n+k=2, When p is above 1, n is above 1, Z 1 are each independently a group represented by any one of the following formulae (T1) to (T14), In formula (2), Y 3 represents a carbon atom or a silicon atom, R 1 ~R 4 each independently represents a methyl group, a tert-butyl group, or a tert-butoxy group, In formula (3), Z 2 is a group represented by the following formula (T14); 【Chemical formula 4】 In formulas (T1) to (T14), A 1 Each independently represents a hydrogen atom, a chlorine atom, a methyl group, a tert-butyl group, -OR, -NR2 or -SR, A 2 Each independently represents a chlorine atom, a methyl group, a tert-butyl group, -OR, -NR2 or -SR, each R independently represents a methyl group or a tert-butyl group, and * represents a bonding site.

2. The method for producing a fluorinated copolymer according to claim 1, wherein The monomer further includes a fluorine-containing monomer having fluorine atoms other than the tetrafluoroethylene, The fluorine-containing monomer comprises at least one selected from the group consisting of fluorine-containing monomers represented by the following formula (X1), formula (X2) and formula (X3); CX 1 X 2 =C(X 3 )-(O) n1 -Rf 1 R 10 …(X1) 【Chemical formula 5】 【Chemical formula 6】 In formula (X1), X 1 , X 2 and X 3 each independently represents a hydrogen atom or a fluorine atom, R 1 represents a perfluoroalkylene group having 1 to 5 carbon atoms, wherein the perfluoroalkylene group may contain an ethereal oxygen atom between carbon-carbon bonds, R 10 Represents hydrogen atom, fluorine atom, -SO2R 11 、-COR 11 or cyano, R 11 each independently represents a hydrogen atom, a fluorine atom, a hydroxyl group or an alkoxy group, n1 is 0 or 1, In formula (X2), X 4 and X 5 each independently represents a hydrogen atom or a fluorine atom, R 2 and Rf 3 Each independently represents a perfluoroalkyl group having 1 to 5 carbon atoms or a fluorine atom, wherein the perfluoroalkyl group may contain an ethereal oxygen atom between carbon-carbon bonds, In formula (X3), X 6 , X 8 and X 9 each independently represents a hydrogen atom or a fluorine atom, X 7 each independently represents a hydrogen atom, a fluorine atom or a trifluoromethyl group, R 20 Each independently represents a fluorine atom or -Rf 4 -R 30 , R 40 Each independently represents a fluorine atom or -Rf 5 -R 50 , R 4 and Rf 5 Each independently represents a perfluoroalkylene group having 1 to 5 carbon atoms, wherein the perfluoroalkylene group may contain an ethereal oxygen atom between carbon-carbon bonds, R 30 and R 50 Respectively independently represent -SO2R 11 、-COR 11 or cyano.

3. The method for producing a fluorinated copolymer according to claim 1 or claim 2, wherein: The monomer further includes at least one fluorine-containing monomer selected from the group consisting of hexafluoropropylene and perfluoro(alkyl vinyl ether).

4. The method for producing a fluorinated copolymer according to claim 1 or claim 2, wherein: The monomers also include non-fluorine monomers having no fluorine atom and having an ethylenically unsaturated group.

5. The method for producing a fluorinated copolymer according to claim 1 or claim 2, wherein: The monomer further includes a non-fluorine monomer having no fluorine atom, having an ethylenically unsaturated group and having at least one reactive group selected from a reactive silyl group, an amino group, an isocyanate group, a hydroxyl group, an epoxy group, an acid anhydride residue, an alkoxycarbonyl group, a carboxyl group and a carbonyl group.

6. The method for producing a fluorinated copolymer according to claim 1 or claim 2, wherein: The monomer further includes a non-fluorine monomer having no fluorine atom, having an ethylenically unsaturated group, and having at least one reactive group selected from the group consisting of a hydroxyl group, an acid anhydride residue, an alkoxycarbonyl group, a carboxyl group, and a carbonyl group.

7. The method for producing a fluorinated copolymer according to claim 1 or claim 2, wherein: The monomer further comprises: At least one fluorine-containing monomer selected from hexafluoropropylene and perfluoro(alkyl vinyl ether), and A non-fluorine monomer having no fluorine atom, having an ethylenically unsaturated group and having an acid anhydride residue.

8. The method for producing a fluorinated copolymer according to claim 1 or claim 2, wherein: The proportion of water in the polymerization medium is less than 10% by volume. In the polymerization medium, solution polymerization is carried out with the monomers.

9. The method for producing a fluorinated copolymer according to claim 1 or claim 2, wherein: The monomer is subjected to suspension polymerization in a polymerization medium containing at least one selected from the compounds represented by the formula (1) or the formula (2) and a polymerization solvent A which is immiscible with water, and water, The proportion of water in the polymerization medium is 10 volume % to 80 volume %, In the formula (1), Y 1 represents a nitrogen atom or an oxygen atom, Y 1 When it is a nitrogen atom, p, m, n and k are each independently an integer satisfying p+m is greater than 1 and p+m+n+k=3, Y 1 When it is an oxygen atom, k is 0, p, m and n are each independently an integer satisfying p+m is greater than 1 and p+m+n=2, When p is above 1, n is above 1, Z 1 are each independently a group represented by any one of the formulas (T1) to (T3), (T7), (T8) and (T10), In the formula (2), Y 3 represents a carbon atom or a silicon atom, R 1 ~R 4 each independently represents a methyl group, a tert-butyl group or a tert-butoxy group, In the formulas (T1) to (T3), (T7), (T8) and (T10), A 1 Each independently represents a hydrogen atom, a methyl group, a tert-butyl group, -OR or -NR2, A 2 Each independently represents a methyl group, a tert-butyl group, -OR or -NR2, each R independently represents a methyl group or a tert-butyl group, and * represents a bonding site.

10. The method for producing a fluorinated copolymer according to claim 1 or claim 2, wherein: In the formula (1), Z 1 Each independently represents a group represented by any one of formulae (T1) to (T3).

11. The method for producing a fluorinated copolymer according to claim 1 or claim 2, wherein: In the formula (1), Z 1 Each independently is a group represented by formula (T1).

12. The method for producing a fluorinated copolymer according to claim 1 or claim 2, wherein: In the formula (2), Y 3 Represents a carbon atom.

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