Production method for aqueous fluorine-containing elastomer dispersion, composition, and aqueous dispersion

Abstract

To provide a method for producing a fluorine-containing elastomer aqueous dispersion, the method being capable of generating a sufficient number of fluorine-containing elastomer particles while greatly suppressing adhesion of the fluorine-containing elastomer to a polymerization tank.SOLUTION: Provided is a method for producing an aqueous dispersion of a fluorine-containing elastomer, comprising polymerizing a fluorine-containing monomer in the presence of a compound (A) containing a functional group capable of reaction by radical polymerization and a hydrophilic group, a polymer (I) containing a polymerization unit (I) based on a monomer (I) represented by general formula (I): CX1X3=CX2R(-CZ1Z2-A0)m, and an aqueous medium, thereby producing an aqueous dispersion of a fluorine-containing elastomer containing a methylene group in the main chain.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a method for producing an aqueous fluorine-containing elastomer dispersion, a composition, and an aqueous dispersion. [Background technology]

[0002] Patent Document 1 describes a method for producing a fluoropolymer, which includes a step of obtaining a fluoropolymer by polymerizing a fluoromonomer in an aqueous medium in the presence of a polymer (1) containing polymerized units (1) based on a monomer represented by the following general formula (1): CX2=CY(-CZ2-O-Rf-A) (1) (In the formula, X's are the same or different and are -H or -F; Y's are -H, -F, an alkyl group or a fluorine-containing alkyl group; Z's are the same or different and are -H, -F, an alkyl group or a fluoroalkyl group; Rf's are fluorine-containing alkylene groups having 1 to 40 carbon atoms or fluorine-containing alkylene groups having 2 to 100 carbon atoms and an ether bond; A's are -COOM, -SO3M or -OSO3M (M's are -H, a metal atom, -NR 7 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 7 is H or an organic group, provided that at least one of X, Y, and Z contains a fluorine atom.

[0003] Patent Document 2 describes a method for producing a fluoropolymer, which comprises emulsion polymerizing one or more fluorinated monomers in an aqueous medium, wherein the aqueous emulsion polymerization is carried out in an aqueous medium in the presence of at least one radical initiator and at least one polyfunctional dispersant [dispersant (D)], and the dispersant (D) is: - a backbone chain comprising repeat units derived from one or more ethylenically unsaturated monomers, - the dispersant (D) has a molecular weight and a molecular weight distribution such that it is substantially free of fractions with molecular weights below 3000, -SO3X in an amount of at least 1.75 meq / g based on the weight of the dispersant (D).a , -PO3X a , and -COOX a (X a is H, an ammonium group, or a monovalent metal; A method is described in which the dispersant (D) is used in an amount of 0.01% by weight and 5.00% by weight based on the total weight of the aqueous medium.

[0004] Patent Document 3 describes a method for producing a fluoropolymer, which comprises emulsion polymerizing one or more fluorinated monomers in an aqueous medium, wherein the aqueous emulsion polymerization is carried out in an aqueous medium in the presence of at least one radical initiator and at least one reactive oligomeric dispersant [dispersant (D)], and the dispersant (D) is: - a backbone chain comprising repeat units derived from one or more ethylenically unsaturated monomers, - has a number average molecular weight of at least 3000 and at most 30000; - contains at least one iodine or bromine atom, -SO3X a , -PO3X a , and -COOX a (In the formula, X a is H, an ammonium group, or a monovalent metal; A method is described in which the dispersant (D) is used in an amount of 0.01% by weight and 3.50% by weight based on the total weight of the aqueous medium. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2019 / 168183 [Patent Document 2] Special Publication No. 2020-510737 [Patent Document 3] Special Publication No. 2020-512447 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present disclosure is to provide a method for producing an aqueous fluorine-containing elastomer dispersion, which can generate a sufficient number of fluorine-containing elastomer particles and can significantly suppress adhesion of the fluorine-containing elastomer to a polymerization vessel. [Means for solving the problem]

[0007] The present disclosure provides a compound (A) containing a functional group reactive by radical polymerization and a hydrophilic group, a polymer (I) containing polymerization units (I) based on a monomer (I) represented by general formula (I), and a method for producing an aqueous dispersion of a fluorine-containing elastomer containing a methylene group in its main chain by polymerizing a fluorine-containing monomer in the presence of an aqueous medium. General formula (I):CX 1 X 3 =CX 2 R(-CZ 1 Z 2 -A 0 ) m (In the formula, X 1 and X 3 are each independently F, Cl, H, or CF; X 2 is H, F, an alkyl group or a fluorine-containing alkyl group; A 0 is an anionic group; R is a linking group; Z 1 and Z 2 are each independently H, F, an alkyl group or a fluorine-containing alkyl group; and m is an integer of 1 or greater.

[0008] The hydrophilic group of compound (A) is -NH2, -P(O)(OM)2, -OP(O)(OM)2, -SO3M, -OSO3M, -COOM, -B(OM)2 or -OB(OM)2 (in each formula, M is H, a metal atom, NR 7 4. An imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent, R7 are H or organic groups and may be the same or different. Any two of them may be bonded to each other to form a ring.

[0009] It is preferable that the compound (A) is at least one compound selected from the group consisting of a fluorine-containing compound (A0) containing a functional group reactive by radical polymerization and a hydrophilic group, a compound (A1) having a triple bond and a hydrophilic group, a fluorine-containing compound (A2) represented by general formula (A2), a fluorine-free compound (A3) represented by general formula (A3), a compound (A4) having an aromatic ring, a hydrophilic group, and an unsaturated double bond, and a fluorine-free compound (A5) represented by general formula (A5). General formula (A2):CX 1 X 2 =CX 3 -Z (In the formula:X 1 ~X 3 are each independently H, F or a fluorine-containing alkyl group; X 1 and X 2 If both are H, then X 3 is F or a fluorine-containing alkyl group; Z is a group represented by -COOM, -SO3M, -OSO3M, -PO(OM)2, -OPO(OM)2, -BO(OM)2 or -OBO(OM)2; M is H, a metal atom, NR 1 4. optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium; R 1 are independently H or an organic group, and R 1 Any two of may be bonded to each other to form a ring.) General formula (A3):CR 1 X 1 =CX 2 -R 2 -COOM (In the formula: R 1 is H or an alkyl group, said alkyl group may contain an ether bond, an ester bond or an amide bond; R 2is a single bond or an alkylene group, and the alkylene group is such that at least one hydrogen atom bonded to a carbon atom is -R 3 -COOM(R 3 is a single bond or an alkylene group), and may contain an ether bond, an ester bond, an amide bond, an unsaturated bond or a cyclic structure; X 1 and X 2 are each independently -R 1 (R 1 as above) or -R 2 -COOM(R 2 is a group represented by the formula (1) as described above; M is H, a metal atom, NR 4 4. optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium; R 4 are independently H or an organic group, and R 4 Any two of may be bonded to each other to form a ring.) General formula (A5):CX 1 X 2 =CX 3 -RZ (In the formula, X 1 , X 2 and X 3 are each independently H or an alkyl group; R is a single bond or an alkylene group; X 1 , X 2 , X 3 and the total number of carbon atoms in R is 0 to 5; Z is -SO3M, -OSO3M, -P(=O)(OM)2, -OP(O)(OM)2, or -B(OM)2; M is H, a metal atom, NR 1 4. optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium; R 1 are independently H or an organic group, and R 1 Any two of may be bonded to each other to form a ring.)

[0010] The compound (A) is preferably a fluorine-containing compound (A0) represented by general formula (A0). General formula (A0):CX i X k =CX j R a -(CZ 1 Z 2 ) k -Y 3 (In the formula, X i , X j and X k are each independently F, Cl, H, or CF; Y 3 is a hydrophilic group; R a is a linking group; Z 1 and Z 2 are each independently H, F, or CF3; and k is 0 or 1. i , X k , X j , R a , Z 1 and Z 2 At least one of contains F. However, when k is 0, R a is a linking group other than a single bond.

[0011] The amount of the compound (A) is preferably 3 to 5000 ppm by mass relative to the aqueous medium.

[0012] The polymer (I) is preferably a polymer (2) containing polymerized units (2) based on a monomer (2) represented by general formula (2). CX2=CY(-O-Rf-A) (2) (In the formula, X's may be the same or different and each represent -H or F; Y's represent -H, -F, an alkyl group or a fluorine-containing alkyl group; Rf's represent a fluorine-containing alkylene group having 1 to 40 carbon atoms or a fluorine-containing alkylene group having 2 to 100 carbon atoms and an ether bond or a keto group; A's represent -COOM, -SO3M, -OSO3M or -C(CF3)2OM (M's represent -H, a metal atom, -NR 7 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R7 is H or an organic group.

[0013] It is preferred that the polymer (I) further contains polymerized units based on other monomers copolymerizable with the monomer (I). The amount of the polymer (I) is preferably 0.0001 to 2% by mass relative to 100% by mass of the aqueous medium. Furthermore, it is preferable to polymerize the fluorine-containing monomer in the presence of a chain transfer agent. The fluorine-containing monomer is preferably polymerized at 10 to 120°C. The fluorine-containing monomer is preferably polymerized at 0.5 to 10 MPaG. It is preferable to polymerize the fluorine-containing monomer substantially in the absence of a fluorine-containing surfactant having no functional group capable of reacting by radical polymerization. The fluorine-containing elastomer preferably contains a vinylidene fluoride unit. The fluorine-containing elastomer preferably contains 50 mol % or more of vinylidene fluoride units based on all monomer units. The fluorine-containing elastomer preferably has a Mooney viscosity (ML1+10(100°C)) of 10-130.

[0014] The present disclosure also provides a fluorine-containing elastomer containing monomer units (A) based on compound (A) which contains a methylene group in the main chain and further contains a functional group reactive by radical polymerization and a hydrophilic group, and a composition containing a polymer (I) containing polymerization units (I) based on monomer (I) represented by general formula (I). General formula (I):CX 1 X 3 =CX 2 R(-CZ 1 Z 2 -A 0 ) m (In the formula, X 1 and X 3 are each independently F, Cl, H, or CF; X 2is H, F, an alkyl group or a fluorine-containing alkyl group; A 0 is an anionic group; R is a linking group; Z 1 and Z 2 are each independently H, F, an alkyl group or a fluorine-containing alkyl group; and m is an integer of 1 or greater.

[0015] The fluorine-containing elastomer preferably contains a vinylidene fluoride unit.

[0016] The present disclosure also provides an aqueous dispersion containing the above composition and an aqueous medium. [Effects of the Invention]

[0017] According to the present disclosure, it is possible to provide a method for producing an aqueous fluorine-containing elastomer dispersion, which can generate a sufficient number of fluorine-containing elastomer particles and can significantly suppress adhesion of the fluorine-containing elastomer to a polymerization vessel. DETAILED DESCRIPTION OF THE INVENTION

[0018] Before describing specific embodiments of the present disclosure, some terms used in the present disclosure will be defined or explained.

[0019] In this disclosure, a fluoroelastomer is an amorphous fluoropolymer. "Amorphous" means that the magnitude of the melting peak (ΔH) appearing in differential scanning calorimetry (DSC) (heating rate 10°C / min) or differential thermal analysis (DTA) (heating rate 10°C / min) of the fluoropolymer is 4.5 J / g or less. Fluorine-containing elastomers exhibit elastomeric properties through crosslinking. Elastomeric properties refer to the ability of a polymer to be stretched and to retain its original length when the force required to stretch the polymer is no longer applied.

[0020] In the present disclosure, a perfluoromonomer is a monomer that does not contain a carbon atom-hydrogen atom bond in the molecule. The perfluoromonomer may be a monomer containing carbon atoms and fluorine atoms, or a monomer in which some of the fluorine atoms bonded to carbon atoms are substituted with chlorine atoms, or a monomer containing nitrogen atoms, oxygen atoms, sulfur atoms, phosphorus atoms, boron atoms, or silicon atoms in addition to carbon atoms. The perfluoromonomer is preferably a monomer in which all hydrogen atoms are substituted with fluorine atoms. The perfluoromonomer does not include a monomer that provides a crosslinkable group.

[0021] The monomer that provides a crosslinking site is a monomer (cure site monomer) that provides a crosslinking site to the fluoropolymer for forming a crosslink with a curing agent. The monomer that provides a crosslinking site includes a monomer that provides a crosslinkable group.

[0022] In the present disclosure, the content of each monomer unit constituting the fluorine-containing elastomer can be calculated by appropriately combining NMR, FT-IR, elemental analysis, and X-ray fluorescence analysis depending on the type of monomer.

[0023] In this disclosure, "organic group" means a group containing one or more carbon atoms or a group formed by removing one hydrogen atom from an organic compound. Examples of the "organic group" are: an alkyl group optionally having one or more substituents; an alkenyl group optionally having one or more substituents; an alkynyl group optionally having one or more substituents; a cycloalkyl group optionally having one or more substituents; a cycloalkenyl group optionally having one or more substituents, a cycloalkadienyl group optionally having one or more substituents, an aryl group optionally having one or more substituents; an aralkyl group optionally having one or more substituents; a non-aromatic heterocyclic group optionally having one or more substituents, a heteroaryl group optionally having one or more substituents; cyano group, formyl group, RaO-, RaCO-, RaSO2-, RaCOO-, RaNRaCO-, RaCONRa-, RaOCO-, RaOSO2-, and RaNRbSO2- (In these formulas, Ra independently represents: an alkyl group optionally having one or more substituents; an alkenyl group optionally having one or more substituents; an alkynyl group optionally having one or more substituents; a cycloalkyl group optionally having one or more substituents; a cycloalkenyl group optionally having one or more substituents, a cycloalkadienyl group optionally having one or more substituents, an aryl group optionally having one or more substituents; an aralkyl group optionally having one or more substituents; a non-aromatic heterocyclic group optionally having one or more substituents, or a heteroaryl group optionally having one or more substituents; Rb is independently H or an alkyl group which may have one or more substituents. Includes. The organic group is preferably an alkyl group which may have one or more substituents.

[0024] In the present disclosure, the term "substituent" refers to a substitutable group. Examples of the "substituent" include an aliphatic group, an aromatic group, a heterocyclic group, an acyl group, an acyloxy group, an acylamino group, an aliphatic oxy group, an aromatic oxy group, a heterocyclic oxy group, an aliphatic oxycarbonyl group, an aromatic oxycarbonyl group, a heterocyclic oxycarbonyl group, a carbamoyl group, an aliphatic sulfonyl group, an aromatic sulfonyl group, a heterocyclic sulfonyl group, an aliphatic sulfonyloxy group, an aromatic sulfonyloxy group, a heterocyclic sulfonyloxy group, a sulfamoyl group, an aliphatic sulfonamido group, an aromatic sulfonamido group, a heterocyclic sulfonamido group, an amino group, and an aliphatic amino group. groups, aromatic amino groups, heterocyclic amino groups, aliphatic oxycarbonylamino groups, aromatic oxycarbonylamino groups, heterocyclic oxycarbonylamino groups, aliphatic sulfinyl groups, aromatic sulfinyl groups, aliphatic thio groups, aromatic thio groups, hydroxy groups, cyano groups, sulfo groups, carboxy groups, aliphatic oxyamino groups, aromatic oxyamino groups, carbamoylamino groups, sulfamoylamino groups, halogen atoms, sulfamoylcarbamoyl groups, carbamoylsulfamoyl groups, dialiphatic oxyphosphinyl groups, and diaromatic oxyphosphinyl groups.

[0025] The aliphatic group may be saturated or unsaturated, and may have a hydroxy group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the aliphatic group include alkyl groups having a total of 1 to 8, preferably 1 to 4, carbon atoms, such as a methyl group, an ethyl group, a vinyl group, a cyclohexyl group, and a carbamoylmethyl group.

[0026] The aromatic group may have, for example, a nitro group, a halogen atom, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the aromatic group include aryl groups having 6 to 12 carbon atoms, preferably 6 to 10 carbon atoms in total, such as a phenyl group, a 4-nitrophenyl group, a 4-acetylaminophenyl group, and a 4-methanesulfonylphenyl group.

[0027] The heterocyclic group may have a halogen atom, a hydroxy group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the heterocyclic group include 5- or 6-membered heterocycles having a total of 2 to 12, preferably 2 to 10, carbon atoms, such as a 2-tetrahydrofuryl group and a 2-pyrimidyl group.

[0028] The acyl group may have an aliphatic carbonyl group, an arylcarbonyl group, a heterocyclic carbonyl group, a hydroxy group, a halogen atom, an aromatic group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the acyl group include acyl groups having a total of 2 to 8, preferably 2 to 4, carbon atoms, such as an acetyl group, a propanoyl group, a benzoyl group, and a 3-pyridinecarbonyl group.

[0029] The acylamino group may have an aliphatic group, an aromatic group, a heterocyclic group, etc., such as an acetylamino group, a benzoylamino group, a 2-pyridinecarbonylamino group, a propanoylamino group, etc. Examples of the acylamino group include acylamino groups having a total of 2 to 12 carbon atoms, preferably 2 to 8 carbon atoms, and alkylcarbonylamino groups having a total of 2 to 8 carbon atoms, such as an acetylamino group, a benzoylamino group, a 2-pyridinecarbonylamino group, a propanoylamino group, etc.

[0030] The aliphatic oxycarbonyl group may be saturated or unsaturated, and may have a hydroxy group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the aliphatic oxycarbonyl group include alkoxycarbonyl groups having a total of 2 to 8, preferably 2 to 4, carbon atoms, such as a methoxycarbonyl group, an ethoxycarbonyl group, and a (t)-butoxycarbonyl group.

[0031] The carbamoyl group may have an aliphatic group, an aromatic group, a heterocyclic group, etc. Examples of the carbamoyl group include an unsubstituted carbamoyl group, an alkylcarbamoyl group having a total of 2 to 9 carbon atoms, preferably an unsubstituted carbamoyl group, or an alkylcarbamoyl group having a total of 2 to 5 carbon atoms, such as an N-methylcarbamoyl group, an N,N-dimethylcarbamoyl group, or an N-phenylcarbamoyl group.

[0032] The aliphatic sulfonyl group may be saturated or unsaturated and may have a hydroxy group, an aromatic group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the aliphatic sulfonyl group include alkylsulfonyl groups having a total of 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, such as a methanesulfonyl group.

[0033] The aromatic sulfonyl group may have a hydroxy group, an aliphatic group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the aromatic sulfonyl group include arylsulfonyl groups having a total of 6 to 10 carbon atoms, such as a benzenesulfonyl group.

[0034] The amino group may have an aliphatic group, an aromatic group, a heterocyclic group, or the like.

[0035] The acylamino group may have, for example, an acetylamino group, a benzoylamino group, a 2-pyridinecarbonylamino group, a propanoylamino group, etc. Examples of the acylamino group include an acylamino group having a total of 2 to 12 carbon atoms, preferably a total of 2 to 8 carbon atoms, and more preferably an alkylcarbonylamino group having a total of 2 to 8 carbon atoms, such as an acetylamino group, a benzoylamino group, a 2-pyridinecarbonylamino group, a propanoylamino group, etc.

[0036] The aliphatic sulfonamide group, aromatic sulfonamide group, and heterocyclic sulfonamide group may be, for example, a methanesulfonamide group, a benzenesulfonamide group, or a 2-pyridinesulfonamide group.

[0037] The sulfamoyl group may have an aliphatic group, an aromatic group, a heterocyclic group, etc. Examples of the sulfamoyl group include a sulfamoyl group, an alkylsulfamoyl group having 1 to 9 carbon atoms in total, a dialkylsulfamoyl group having 2 to 10 carbon atoms in total, an arylsulfamoyl group having 7 to 13 carbon atoms in total, and a heterocyclic sulfamoyl group having 2 to 12 carbon atoms in total, more preferably a sulfamoyl group, an alkylsulfamoyl group having 1 to 7 carbon atoms in total, a dialkylsulfamoyl group having 3 to 6 carbon atoms in total, an arylsulfamoyl group having 6 to 11 carbon atoms in total, and a heterocyclic sulfamoyl group having 2 to 10 carbon atoms in total, such as a sulfamoyl group, a methylsulfamoyl group, an N,N-dimethylsulfamoyl group, a phenylsulfamoyl group, and a 4-pyridine sulfamoyl group.

[0038] The aliphatic oxy group may be saturated or unsaturated and may have a methoxy group, an ethoxy group, an i-propyloxy group, a cyclohexyloxy group, a methoxyethoxy group, etc. Examples of the aliphatic oxy group include alkoxy groups having a total of 1 to 8 carbon atoms, preferably 1 to 6 carbon atoms, such as a methoxy group, an ethoxy group, an i-propyloxy group, a cyclohexyloxy group, and a methoxyethoxy group.

[0039] The aromatic amino group and heterocyclic amino group may have an aliphatic group, an aliphatic oxy group, a halogen atom, a carbamoyl group, a heterocyclic group fused with the aryl group, an aliphatic oxycarbonyl group, preferably an aliphatic group having 1 to 4 carbon atoms in total, an aliphatic oxy group having 1 to 4 carbon atoms in total, a halogen atom, a carbamoyl group having 1 to 4 carbon atoms in total, a nitro group, or an aliphatic oxycarbonyl group having 2 to 4 carbon atoms in total.

[0040] The aliphatic thio group may be saturated or unsaturated and includes alkylthio groups having a total of 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms, such as a methylthio group, an ethylthio group, a carbamoylmethylthio group, and a t-butylthio group.

[0041] The carbamoylamino group may have an aliphatic group, an aryl group, a heterocyclic group, etc. Examples of the carbamoylamino group include a carbamoylamino group, an alkylcarbamoylamino group having 2 to 9 carbon atoms in total, a dialkylcarbamoylamino group having 3 to 10 carbon atoms in total, an arylcarbamoylamino group having 7 to 13 carbon atoms in total, and a heterocyclic carbamoylamino group having 3 to 12 carbon atoms in total, preferably a carbamoylamino group, an alkylcarbamoylamino group having 2 to 7 carbon atoms in total, a dialkylcarbamoylamino group having 3 to 6 carbon atoms in total, an arylcarbamoylamino group having 7 to 11 carbon atoms in total, and a heterocyclic carbamoylamino group having 3 to 10 carbon atoms in total, such as a carbamoylamino group, a methylcarbamoylamino group, an N,N-dimethylcarbamoylamino group, a phenylcarbamoylamino group, and a 4-pyridinecarbamoylamino group.

[0042] In this disclosure, ranges expressed by endpoints include all numbers subsumed within that range (e.g., 1 to 10 includes 1.4, 1.9, 2.33, 5.75, 9.98, etc.).

[0043] In this disclosure, the term "at least 1" includes all numbers greater than or equal to 1 (e.g., at least 2, at least 4, at least 6, at least 8, at least 10, at least 25, at least 50, at least 100, etc.).

[0044] Specific embodiments of the present disclosure will be described in detail below, but the present disclosure is not limited to the following embodiments.

[0045] The production method of the present disclosure is a production method for an aqueous dispersion of a fluorine-containing elastomer having a methylene group in its main chain, and produces an aqueous dispersion of a fluorine-containing elastomer having a methylene group in its main chain by polymerizing a fluorine-containing monomer in the presence of a compound (A) containing a functional group reactive by radical polymerization and a hydrophilic group, a polymer (I) containing polymerization units (I) based on a monomer (I) represented by general formula (I), and an aqueous medium. General formula (I):CX 1 X 3 =CX 2 R(-CZ 1 Z 2 -A 0 ) m (In the formula, X 1 and X 3 are each independently F, Cl, H, or CF; X 2 is H, F, an alkyl group or a fluorine-containing alkyl group; A 0 is an anionic group; R is a linking group; Z 1 and Z 2 are each independently H, F, an alkyl group or a fluorine-containing alkyl group; and m is an integer of 1 or greater.

[0046] By using in combination the compound (A) having a hydrophilic group and capable of reacting with a fluorine-containing monomer and the polymer (I) having an anionic group, it is possible to generate a sufficient number of fluorine-containing elastomer particles for smoothly progressing the polymerization reaction, and also to significantly suppress adhesion of the fluorine-containing elastomer to the polymerization vessel.

[0047] (Compound (A)) In the production method of the present disclosure, a fluorine-containing monomer is polymerized in the presence of a compound (A) containing a functional group reactive in radical polymerization and a hydrophilic group, since a sufficient number of fluorine-containing elastomer particles can be generated and adhesion of the fluorine-containing elastomer to the polymerization vessel can be significantly suppressed. In the production method of the present disclosure, one or more compounds (A) may be used. The compound (A) may be either a fluorine-containing compound or a fluorine-free compound.

[0048] In the present disclosure, a hydrophilic group refers to a group that exhibits affinity for an aqueous medium. Compound (A) is preferably a compound containing an anionic or nonionic hydrophilic group, and more preferably a compound containing an anionic hydrophilic group. Compound (A) may, for example, contain only anionic hydrophilic groups, or only nonionic hydrophilic groups. Compound (A) may be a compound containing an anionic hydrophilic group alone, a compound containing a nonionic hydrophilic group alone, or a combination of a compound containing an anionic hydrophilic group and a compound containing a nonionic hydrophilic group. It is believed that compound (A) containing a hydrophilic group not only forms highly stable particles, but also has a high particle-forming ability, resulting in a large number of particles per unit amount of water, and a higher polymerization rate.

[0049] Examples of the hydrophilic group in compound (A) include -NH, -P(O)(OM), -OP(O)(OM), -SO, -OSO, -COOM, -B(OM), and -OB(OM) (in each formula, M represents H, a metal atom, or NR 7 4. An imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent, R 7 are H or organic groups and may be the same or different. Any two of them may be bonded to each other to form a ring. ) are examples of the hydrophilic group. Among them, -SO3M or -COOM is preferred, and -COOM is more preferred. R 7The organic group in R is preferably an alkyl group. 7 As for H or C 1-10 is preferably an organic group represented by the formula: 1-4 The organic group is more preferably H or C 1-4 An alkyl group such as the group shown below is more preferred, and H is most preferred. When two M's are included in each formula, the two M's may be the same or different. The metal atom includes a monovalent or divalent metal atom, and is preferably an alkali metal (Group 1) or alkaline earth metal (Group 2), more preferably Na, K, or Li.

[0050] The "functional group capable of reacting by radical polymerization" in the compound (A) includes a group containing a radically polymerizable unsaturated bond.

[0051] Examples of the group having a radical polymerizable unsaturated bond include groups having an ethylenically unsaturated bond such as a vinyl group and an allyl group. The group having an ethylenically unsaturated bond is represented by the following formula: CX e X g =CX f R- (In the formula, X e , X f and X g are each independently F, Cl, H, CF3, CF2H, CFH2, or CH3; and R is a linking group. The linking group for R can be represented by the formula: a Examples of linking groups include:

[0052] Examples of groups having a radically polymerizable unsaturated bond include -CH=CH2 and -CF=CH 2、 -CH=CF 2、-CF=CF2, -CH2-CH=CH2, -CF2-CF=CH2, -CF2-CF=CF2, -(C=O)-CH=CH2, -(C=O)-CF=CH2, -(C=O)-CH=CF2, -(C=O)-CF=CF2, -(C=O)-C(CH3)=CH2, -(C=O )-C(CF3)=CH2, -(C=O)-C(CH3)=CF2, -(C=O)-C(CF3)=CF2, -O-CH2-CH=CH2, -O-CF2-CF=CH2, -O-CH2-CH=CF2, -O-CF=CF2, -O-CF2-CF=CF2, etc.

[0053] Since compound (A) has a functional group capable of reacting by radical polymerization, it is presumed that when used in the above polymerization, it reacts with the fluorine-containing monomer in the early stage of the polymerization reaction to form highly stable particles having hydrophilic groups derived from compound (A). For this reason, it is considered that when polymerization is carried out in the presence of compound (A), the number of fluorine-containing elastomer particles generated during polymerization increases.

[0054] The amount of compound (A) used in polymerizing the fluorine-containing monomer is preferably 3 to 5,000 ppm by mass, more preferably 5 ppm by mass or more, even more preferably 10 ppm by mass or more, particularly preferably 20 ppm by mass or more, and most preferably 30 ppm by mass or more, and more preferably 1,000 ppm by mass or less, even more preferably 500 ppm by mass or less, particularly preferably 200 ppm by mass or less, and most preferably 100 ppm by mass or less, based on the aqueous medium. By setting the amount of compound (A) within the above range, a larger amount of fluorine-containing elastomer particles can be generated, and adhesion of the fluorine-containing elastomer to the polymerization vessel can be further suppressed.

[0055] It is also preferable to adjust the amount of compound (A) depending on the type of polymerization initiator used in the polymerization and the polymerization temperature. When a non-redox polymerization initiator is used as the polymerization initiator and polymerization is carried out at 40 to 70°C, the amount of compound (A) is preferably 3 to 300 ppm by mass, more preferably 3 to 150 ppm by mass, still more preferably 5 to 100 ppm by mass, and most preferably 8 to 80 ppm by mass, relative to the aqueous medium. When a non-redox polymerization initiator is used as the polymerization initiator and polymerization is carried out at more than 70°C and not more than 98°C, the amount of compound (A) relative to the aqueous medium is preferably 3 to 500 ppm by mass, more preferably 3 to 200 ppm by mass, still more preferably 5 to 120 ppm by mass, and most preferably 20 to 110 ppm by mass. When a redox polymerization initiator is used as the polymerization initiator and polymerization is carried out at 10°C or higher and lower than 40°C, the amount of compound (A) is preferably 3 to 300 ppm by mass, more preferably 3 to 100 ppm by mass, still more preferably 5 to 80 ppm by mass, and most preferably 10 to 70 ppm by mass, relative to the aqueous medium. When a redox polymerization initiator is used as the polymerization initiator and polymerization is carried out at 40 to 70°C, the amount of compound (A) relative to the aqueous medium is preferably 3 to 500 ppm by mass, more preferably 5 to 300 ppm by mass, still more preferably 10 to 200 ppm by mass, and most preferably 15 to 150 ppm by mass. When a redox polymerization initiator is used as the polymerization initiator and polymerization is carried out at more than 70°C and not more than 98°C, the amount of compound (A) relative to the aqueous medium is preferably 5 to 500 ppm by mass, more preferably 8 to 300 ppm by mass, still more preferably 15 to 200 ppm by mass, and most preferably 20 to 150 ppm by mass. By using the compound (A) in an amount within the above range, the adhesion rate can be reduced and the polymerization time can be shortened.

[0056] The compound (A) is preferably added before the polymerization initiator is added to start the polymerization reaction, and is preferably added only before the polymerization reaction is started, and not added after the polymerization has started.

[0057] The compound (A) is preferably at least one compound selected from the group consisting of a fluorine-containing compound (A0) containing a functional group reactive by radical polymerization and a hydrophilic group, a compound (A1) having a triple bond and a hydrophilic group, a fluorine-containing compound (A2) represented by general formula (A2), a fluorine-free compound (A3) represented by general formula (A3), a compound (A4) having an aromatic ring, a hydrophilic group and an unsaturated double bond, and a fluorine-free compound (A5) represented by general formula (A5), because it can generate a larger amount of fluorine-containing elastomer particles and further suppress adhesion of the fluorine-containing elastomer to the polymerization vessel.

[0058] The fluorine-containing compound (A0) is a compound containing a fluorine atom in the molecule and containing a functional group capable of reacting by radical polymerization and a hydrophilic group. In the production method of the present disclosure, one or more types of compound (A0) may be used.

[0059] Examples of the hydrophilic group in the fluorine-containing compound (A0) include -NH, -P(O)(OM), -OP(O)(OM), -SO, -OSO, -COOM, -B(OM), and -OB(OM) (in each formula, M represents H, a metal atom, or NR 7 4. An imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent, R 7 are H or organic groups and may be the same or different. Any two of them may be bonded to each other to form a ring. ) are examples of the hydrophilic group. Among them, -SO3M or -COOM is preferred, and -COOM is more preferred. R 7 The organic group in R is preferably an alkyl group. 7 As for H or C 1-10 is preferably an organic group represented by the formula: 1-4 The organic group is more preferably H or C 1-4An alkyl group such as the group shown below is more preferred, and H is most preferred. When two M's are included in each formula, the two M's may be the same or different. The metal atom includes a monovalent or divalent metal atom, and is preferably an alkali metal (Group 1) or alkaline earth metal (Group 2), more preferably Na, K, or Li.

[0060] The "functional group capable of reacting by radical polymerization" in the compound (A0) includes a group containing a radically polymerizable unsaturated bond.

[0061] Examples of the group having a radical polymerizable unsaturated bond include groups having an ethylenically unsaturated bond such as a vinyl group and an allyl group. The group having an ethylenically unsaturated bond is represented by the following formula: CX e X g =CX f R- (In the formula, X e , X f and X g are each independently F, Cl, H, CF3, CF2H, CFH2, or CH3; and R is a linking group. The linking group for R can be represented by the formula: a Examples of linking groups include:

[0062] Examples of groups having a radically polymerizable unsaturated bond include -CH=CH2 and -CF=CH 2、 -CH=CF 2、 -CF=CF2, -CH2-CH=CH2, -CF2-CF=CH2, -CF2-CF=CF2, -(C=O)-CH=CH2, -(C=O)-CF=CH2, -(C=O)-CH=CF2, -(C=O)-CF=CF2, -(C=O)-C(CH3)=CH2, -(C=O )-C(CF3)=CH2, -(C=O)-C(CH3)=CF2, -(C=O)-C(CF3)=CF2, -O-CH2-CH=CH2, -O-CF2-CF=CH2, -O-CH2-CH=CF2, -O-CF=CF2, -O-CF2-CF=CF2, etc.

[0063] As the fluorine-containing compound (A0), a fluorine-containing compound (A0) represented by general formula (A0) is preferred, since it can generate a larger amount of fluorine-containing elastomer particles and can further suppress adhesion of the fluorine-containing elastomer to the polymerization vessel. General formula (A0):CX i X k =CX j R a -(CZ 1 Z 2 ) k -Y 3 (In the formula, X i , X j and X k are each independently F, Cl, H, or CF; Y 3 is a hydrophilic group; R a is a linking group; Z 1 and Z 2 are each independently H, F, or CF3; and k is 0 or 1. i , X k , X j , R a , Z 1 and Z 2 At least one of contains F. However, when k is 0, R a is a linking group other than a single bond.

[0064] Y in general formula (A0) 3 is a hydrophilic group. As the hydrophilic group, -NH2, -P(O)(OM)2, -OP(O)(OM)2, -SO3M, -OSO3M, -COOM-B(OM)2, -OB(OM)2 (in each formula, M is H, a metal atom, NR 7 4. An imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent, R 7are H or organic groups and may be the same or different. Any two of them may be bonded to each other to form a ring. ) is preferred. As the hydrophilic group, -SO3M or -COOM is more preferred, and -COOM is even more preferred. R 7 The organic group in R is preferably an alkyl group. 7 As for H or C 1-10 is preferably an organic group represented by the formula: 1-4 The organic group is more preferably H or C 1-4 More preferred is an alkyl group, and most preferred is H. The metal atom includes monovalent or divalent metal atoms, and is preferably an alkali metal (Group 1) or alkaline earth metal (Group 2), and more preferably Na, K or Li.

[0065] R in general formula (A0) a is a linking group. In the present disclosure, the term "linking group" refers to a divalent linking group. The linking group is preferably a single bond or a group containing at least one carbon atom. However, when k is 0, R a is a linking group other than a single bond, and is preferably a group containing at least one carbon atom. The number of carbon atoms in the linking group may be 2 or more, 4 or more, 8 or more, 10 or more, or 20 or more. There is no upper limit to the number of carbon atoms in the linking group, but it may be, for example, 100 or less, or 50 or less.

[0066] The linking group may be linear or branched, cyclic or acyclic in structure, saturated or unsaturated, substituted or unsubstituted, and may optionally contain one or more heteroatoms selected from the group consisting of sulfur, oxygen, and nitrogen, and may optionally contain one or more functional groups selected from the group consisting of ester, amide, sulfonamide, carbonyl, carbonate, urethane, urea, and carbamate. The linking group may not contain carbon atoms but may be a catenary heteroatom such as oxygen, sulfur, or nitrogen.

[0067] R a is preferably a catenary heteroatom such as oxygen, sulfur, or nitrogen, or a divalent organic group.

[0068] R a When R is a divalent organic group, the hydrogen atom bonded to the carbon atom may be replaced with a halogen other than fluorine, such as chlorine, and may or may not contain a double bond. a may be either linear or branched, and may be either cyclic or acyclic. a may contain functional groups (e.g., esters, ethers, ketones, amines, halides, etc.).

[0069] R a may also be a non-fluorinated divalent organic group, or a partially fluorinated or perfluorinated divalent organic group.

[0070] R a Examples of the hydrocarbon group include a hydrocarbon group in which no fluorine atoms are bonded to a carbon atom, a hydrocarbon group in which some of the hydrogen atoms bonded to a carbon atom are substituted with fluorine atoms, a hydrocarbon group in which all of the hydrogen atoms bonded to a carbon atom are substituted with fluorine atoms, -(C=O)-, -(C=O)-O-, or a hydrocarbon group containing an ether bond, which may contain an oxygen atom, a double bond, or a functional group.

[0071] R a is preferably —(C═O)—, —(C═O)—O—, or a hydrocarbon group having 1 to 100 carbon atoms which may contain an ether bond and may contain a carbonyl group, and in the hydrocarbon group, some or all of the hydrogen atoms bonded to the carbon atoms may be substituted with fluorine.

[0072] R a Preferably, -(CH2) a -, -(CF2) a -, -O-(CF2) a -, -(CF2) a -O-(CF2) b -, -O(CF2) a -O-(CF2) b -, -(CF2) a-[O-(CF2) b ] c -, -O(CF2) a -[O-(CF2) b ] c -, -[(CF2) a -O] b -[(CF2) c -O] d -, -O[(CF2) a -O] b -[(CF2) c -O] d -, -O-[CF2CF(CF3)O] a -(CF2) b -, -(C=O)-, -(C=O)-O-, -(C=O)-(CH2) a -, -(C=O)-(CF2) a -, -(C=O)-O-(CH2) a -, -(C=O)-O-(CF2) a -, -(C=O)-[(CH2) a -O] b -, -(C=O)-[(CF2) a -O] b -, -(C=O)-O[(CH2) a -O] b -, -(C=O)-O[(CF2) a -O] b -, -(C=O)-O[(CH2) a -O] b -(CH2) c -, -(C=O)-O[(CF2) a -O] b -(CF2) c -, -(C=O)-(CH2) a -O-(CH2) b -, -(C=O)-(CF2) a -O-(CF2) b -, -(C=O)-O-(CH2) a -O-(CH2) b -, -(C=O)-O-(CF2) a -O-(CF2) b At least one selected from -, -(C=O)-O-C6H4-, and combinations thereof.

[0073] In the formula, a, b, c, and d are independently at least 1. a, b, c, and d may independently be 2 or more, 3 or more, 4 or more, 10 or more, or 20 or more. The upper limit of a, b, c, and d is, for example, 100.

[0074] R a Specific examples of suitable alkyl include -O-CF2-, -O-CF2CF2-, -O-CF2CF2CF2-, -O-CF2CF(CF3)-O-, -O-CF2CF(CF3)-O-CF2-, -CF2-O-, -CF2-O-CF2-, -CF2-O-CH2-, -CF2-O-CH2CF2-, -CF2-O-CF2CF2-, -CF2-O-CF2CH2-, -CF2-O-CF2CF2 CH2-, -CF2-O-CF(CF3)-, -CF2-O-CF(CF3)CF2-, -CF2-O-CF(CF3)CF2-O-, -CF2-O-CF(CF3)CH2-, -(C=O)- , -(C=O)-O-, -(C=O)-(CH2)-, -(C=O)-(CF2)-, -(C=O)-O-(CH2)-, -(C=O)-O-(CF2)-, -(C=O)-[(CH2)2-O] n -, -(C=O)-[(CF2)2-O] n -, -(C=O)-O[(CH2)2-O] n -, -(C=O)-O[(CF2)2-O] n -, -(C=O)-O[(CH2)2-O] n -(CH2)-, -(C=O)-O[(CF2)2-O] n -(CF2)-, -(C=O)-(CH2)2-O-(CH2)-, -(C=O)-(CF2)2-O-(CF2)-, -(C=O)-O-(CH2)2-O-(CH2)-, -(C=O)-O-(CF2)2-O-(CF2)-, -(C=O)-O-C6H4-, etc. a-O-CF2-, -O-CF2CF2-, -O-CF2CF2CF2-, -O-CF2CF(CF3)-O-, -O-CF2CF(CF3)-O-CF2-, -CF2-O-, -CF2-O-CF2-, -CF2-O-CF2CF2-, -CF2- O-CF(CF3)-, -CF2-O-CF(CF3)CF2-, -CF2-O-CF(CF3)CF2-O-, -(C=O)-, -(C=O)-O-, -(C=O)-(CH2)-, -(C=O)-O-(CH2)-, -(C=O)-O[(CH2)2-O] n -, -(C=O)-O[(CH2)2-O] n -(CH2)-, -(C=O)-(CH2)2-O-(CH2)-, or -(C=O)-O-C6H4- is preferred. In the above formula, n is an integer of 1 to 10.

[0075] -R in general formula (A0) a -(CZ 1 Z 2 ) k-としては、-O-CF2-、-O-CF2CF2-、-O-CF2CF2CF2-、-O-CF2CF(CF3)-O-CF2-、-CF2-O-CF2-、-CF2-O-CF(CF3)-、-CF2-OC(CF3)2-、-CF2-O-CF2-CF2-、-CF2-O-CF2-CF(CF3)-、-CF2-O-CF2-C(C F3)2-、-CF2-O-CF2CF2-CF2-、-CF2-O-CF2CF2-CF(CF3)-、-CF2-O-CF2CF2-C(CF3)2-、-CF2-O -CF(CF3)-CF2-、-CF2-O-CF(CF3)-CF(CF3)-、-CF2-O-CF(CF3)-C(CF3)2-、-CF2-O-CF(CF3)- CF2-、-CF2-O-CF(CF3)-CF(CF3)-、-CF2-O-CF(CF3)-C(CF3)2-、-CF2-O-CF(CF3)CF2-CF2-、 -CF2-O-CF(CF3)CF2-CF(CF3)-、-CF2-O-CF(CF3)CF2-C(CF3)2-、-CF2-O-CF(CF3)CF2-O-CF2 -、-CF2-O-CF(CF3)CF2-O-CF(CF3)-、-CF2-O-CF(CF3)CF2-OC(CF3)2-、-(C=O)-、-(C=O)-O-、 -(C=O)-(CH2)-、-(C=O)-(CF2)-、-(C=O)-O-(CH2)-、-(C=O)-O-(CF2)-、-(C=O)-[(CH2)2-O] n -(CH2)-、-(C=O)-[(CF2)2-O] n -(CF2)-、-(C=O)-[(CH2)2-O] n -(CH2)-(CH2)-、-(C=O)-[(CF2)2-O] n -(CF2)-(CF2)-、-(C=O)-O[(CH2)2-O] n -(CF2)-、-(C=O)-O[(CH2)2-O] n -(CH2)-(CH2)-、-(C=O)-O[(CF2)2-O] n -(CF2)-、-(C=O)-O[(CF2)2-O] n-(CF2)-(CF2)-, -(C=O)-(CH2)2-O-(CH2)-(CH2)-, -(C=O)-(CF2)2-O-(CF2)-(CF2)-, -(C=O)-O-(CH2)2-O-(CH2)-(CH2)-, -(C=O)-O-(CF2)2-O-(CF2) -(CF2)-, -(C=O)-O-(CH2)2-O-(CH2)-C(CF3)2-, -(C=O)-O-(CF2)2-O-(CF2)-C(CF3)2-, or -(C=O)-O-C6H4-C(CF3)2-, preferably -O-CF2-, -O-CF2CF2-, -O -CF2CF2CF2-, -O-CF2CF(CF3)-O-, -O-CF2CF(CF3)-O-CF2-, -CF2-O-CF(CF3)-, -CF2-O-CF2-CF(CF3)-, -CF2-O-CF2CF2-CF(CF3)-, -CF2-O-CF(CF3)-CF (CF3)-, -CF2-O-CF(CF3)CF2-CF(CF3)-, -CF2-O-CF(CF3)CF2-O-CF(CF3)-, -(C=O)-, -(C=O)-O-(CH2)-, -(C=O)-O-(CH2)-(CH2)-, -(C=O)-O[(CH2)2-O] n -(CH2)-(CH2)-, -(C=O)-O-(CH2)2-O-(CH2)-C(CF3)2-, or -(C=O)-O-C6H4-C(CF3)2- is more preferred. In the above formula, n is an integer of 1 to 10.

[0076] Specific examples of the fluorine-containing compound (A0) include: [ka] (In the formula, X j and Y 3 is the same as above. n is an integer of 1 to 10.

[0077] R a The following general formula (r1): -(C=O) h -(O) i -CF2-O-(CX 6 2) e -{O-CF(CF3)} f-(O) g - (r1) (In the formula, X 6 are each independently H, F, or CF3, e is an integer of 0 to 3, f is an integer of 0 to 3, g is 0 or 1, h is 0 or 1, and i is 0 or 1), and a divalent group represented by the following general formula (r2): -(C=O) h -(O) i -CF2-O-(CX 7 2) e -(O) g - (r2) (where X 7 are each independently H, F or CF3, e is an integer of 0 to 3, g is 0 or 1, h is 0 or 1, and i is 0 or 1. Divalent groups represented by the following formula are also preferred.

[0078] -R in general formula (A0) a -(CZ 1 Z 2 ) k - can also be represented by the following formula (t1): -(C=O) h -(O) i -CF2-O-(CX 6 2) e -{O-CF(CF3)} f -(O) g -CZ 1 Z 2 - (t1) (In the formula, X 6 are each independently H, F, or CF3, e is an integer of 0 to 3, f is an integer of 0 to 3, g is 0 or 1, h is 0 or 1, i is 0 or 1, and Z 1 and Z 2 are each independently F or CF3), and in formula (t1), Z 1 and Z 2 More preferably, one is F and the other is CF3.

[0079] In addition, in the above general formula (A0), -R a -(CZ 1 Z 2 ) k- is the following formula (t2): -(C=O) h -(O) i -CF2-O-(CX 7 2) e -(O) g -CZ 1 Z 2 - (t2) (In the formula, X 7 are each independently H, F, or CF3, e is an integer of 0 to 3, g is 0 or 1, h is 0 or 1, i is 0 or 1, and Z 1 and Z 2 are each independently F or CF3), and in formula (t2), Z 1 and Z 2 More preferably, one is F and the other is CF3.

[0080] The fluorine-containing compound (A0) has a hydrophilic group (Y 3 It is also preferable that the portion excluding X has a C—F bond and does not have a C—H bond. i , X j , and X k All of the are F and R a is preferably a perfluoroalkylene group having one or more carbon atoms, and the perfluoroalkylene group may be either linear or branched, may be cyclic or acyclic, and may contain at least one catenary heteroatom. The number of carbon atoms in the perfluoroalkylene group may be 2 to 20, or may be 4 to 18.

[0081] The fluorine-containing compound (A0) may be partially fluorinated. That is, the compound represented by the general formula (A0) may contain a hydrophilic group (Y 3 It is also preferred that the moiety excluding (a) has at least one hydrogen atom bonded to a carbon atom and at least one fluorine atom bonded to a carbon atom.

[0082] The fluorine-containing compound (A0) is also preferably a compound represented by the following formula (Aa). CF2=CF-O-Rf 0 -Y 3 (Aa) (In the formula, Y 3 is a hydrophilic group, and Rf 0 is a perfluorinated divalent linking group which may be linear or branched, cyclic or acyclic in structure, saturated or unsaturated, substituted or unsubstituted, and which optionally contains one or more heteroatoms selected from the group consisting of sulfur, oxygen, and nitrogen.

[0083] The fluorine-containing compound (A0) is also preferably a compound represented by the following formula (Ab). CH2=CH-O-Rf 0 -Y 3 (Ab) (In the formula, Y 3 is a hydrophilic group, and Rf 0 is a perfluorinated divalent linking group defined by formula (Aa).

[0084] In general formula (A0), Y 3 One of the preferred embodiments is -OSO3M. 3 is -OSO3M, examples of the fluorine-containing compound (A0) include CF2=CF(OCF2CF2CH2OSO3M), CH2=CH((CF2)4CH2OSO3M), CF2=CF(O(CF2)4CH2OSO3M), CF2=CF(OCF2CF(CF3)CH2OSO3M), CF2=CF(OCF2CF(CF3)OCF2CF2CH2OSO3M), CH2=CH((CF2)4CH2OSO3M), CF2=CF(OCF2CF2SON(CH3)CH2CH2OSO3M), CH2=CH(CF2CF2CH2OSO3M), CF2=CF(OCF2CF2CF2CF2SON(CH3)CH2CH2OSO3M), CH2=CH(CF2CF2CH2OSO3M), and the like. In the above formulas, M is the same as above.

[0085] In general formula (A0), Y 3 Another preferred form is -SO3M. 3is -SO3M, examples of the fluorine-containing compound (A0) include CF2=CF(OCF2CF2SO3M), CF2=CF(O(CF2)4SO3M), CF2=CF(OCF2CF(CF3)SO3M), CF2=CF(OCF2CF(CF3)OCF2CF2SO3M), CH2=CH(CF2CF2SO3M), CF2=CF(OCF2CF(CF3)OCF2CF2CF2CF2SO3M), CH2=CH((CF2)4SO3M), CH2=CH((CF2)3SO3M), etc. In the above formulas, M is the same as above.

[0086] In general formula (A0), Y 3 -COOM is also a preferred form. 3 is -COOM, examples of the fluorine-containing compound (A0) include CF2=CF(OCF2CF2COOM), CF2=CF(OCF2CF2CF2COOM), CF2=CF(O(CF2)5COOM), CF2=CF(OCF2CF(CF3)COOM), CF2=CF(OCF2CF(CF3)O(CF2) n COOM) (n is greater than 1), CH2=CH(CF2CF2COOM), CH2=CH((CF2)4COOM), CH2=CH((CF2)3COOM), CF2=CF(OCF2CF2SO2NR'CH2COOM), CF2=CF(O(CF2)4SO2NR'CH2COOM), CF2=CF(OCF2CF(CF3)SO2NR'CH2COOM), CF2=CF(OCF2CF(CF3)OC F2CF2SO2NR'CH2COOM), CH2=CH(CF2CF2SO2NR'CH2COOM), CF2=CF(OCF2CF(CF3)OCF2CF2CF2CF2SO2NR'CH2COOM), CH2=CH((CF2)4SO2NR'CH2COOM), CH2=CH(CF2CF2SO2NR'CH2COOM), CH2=CH((CF2)3SO2NR'CH2COOM), etc. In the above formula, R' represents H or C 1-4 is an alkyl group, and M is the same as above.

[0087] In general formula (A0), Y 3In another preferred embodiment, Y is -OP(O)(OM)2. 3 is -OP(O)(OM)2, examples of the fluorine-containing compound (A0) include CF2=CF(OCF2CF2CH2OP(O)(OM)2), CF2=CF(O(CF2)4CH2OP(O)(OM)2), CF2=CF(OCF2CF(CF3)CH2OP(O)(OM)2), CF2=CF(OCF2CF(CF3)OCF2CF2CH2OP(O)(OM)2), CF2=CF(OCF2CF2 SO2N(CH3)CH2CH2OP(O)(OM)2), CF2=CF(OCF2CF2CF2CF2SO2N(CH3)CH2CH2OP(O)(OM)2), CH2=CH(CF2CF2CH2OP(O)(OM)2, CH2=CH((CF2)4CH2OP(O)(OM)2), CH2=CH((CF2)3CH2OP(O)(OM)2), etc. In the above formula, M is the same as above.

[0088] In general formula (A0), Y 3 In another preferred embodiment, Y is -P(O)(OM)2. 3 is -P(O)(OM)2, examples of the fluorine-containing compound (A0) include CF2=CF(OCF2CF2P(O)(OM)2), CF2=CF(O(CF2)4P(O)(OM)2), CF2=CF(OCF2CF(CF3)P(O)(OM)2), CF2=CF(OCF2CF(CF3)OCF2CF2P(O)(OM)2), CH2=CH(CF2CF2P(O)(OM)2), CH2=CH((CF2)4P(O)(OM)2), CH2=CH((CF2)3P(O)(OM)2), and the like, wherein M is as defined above.

[0089] The fluorine-containing compound (A0) is a compound represented by the general formula (5): CX2=CY(-CZ2-O-Rf-Y 3 ) (5) (In the formula, X's may be the same or different and each represent -H or -F; Y's may be -H, -F, an alkyl group or a fluorine-containing alkyl group; and Z's may be the same or different and each represent -H, -F, an alkyl group or a fluorine-containing alkyl group. Rf's may be a fluorine-containing alkylene group having 1 to 40 carbon atoms or a fluorine-containing alkylene group having 2 to 100 carbon atoms and an ether bond. Y 3 is the same as above.), a compound represented by general formula (6): CX2=CY(-O-Rf-Y 3 ) (6) (In the formula, X may be the same or different and is -H or -F; Y is -H, -F, an alkyl group or a fluorine-containing alkyl group; and Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms or a fluorine-containing alkylene group having 2 to 100 carbon atoms and an ether bond. Y 3 is the same as above.) and a compound represented by general formula (7): CX2=CY(-Rf-Y 3 ) (7) (In the formula, X may be the same or different and is -H or -F; Y is -H, -F, an alkyl group or a fluorine-containing alkyl group; and Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms or a fluorine-containing alkylene group having 2 to 100 carbon atoms and an ether bond. Y 3 is the same as above. Preferably, the compound is at least one selected from the group consisting of compounds represented by

[0090] The fluorine-containing alkylene group having 2 to 100 carbon atoms and an ether bond is an alkylene group that does not contain a structure in which an oxygen atom is at the terminal and that contains an ether bond between carbon atoms.

[0091] In general formula (5), X is -H or -F. Both Xs may be -F, or at least one X may be -H. For example, one X may be -F and the other may be -H, or both Xs may be -H.

[0092] In general formula (5), Y is -H, -F, an alkyl group, or a fluorine-containing alkyl group. The alkyl group is an alkyl group that does not contain a fluorine atom, and may have one or more carbon atoms. The alkyl group preferably has six or fewer carbon atoms, more preferably four or fewer carbon atoms, and even more preferably three or fewer carbon atoms. The fluorine-containing alkyl group is an alkyl group that contains at least one fluorine atom, and may have one or more carbon atoms. The fluorine-containing alkyl group preferably has six or fewer carbon atoms, more preferably four or fewer carbon atoms, and even more preferably three or fewer carbon atoms. Y is preferably -H, -F, or -CF3, and more preferably -F.

[0093] In general formula (5), Z's are the same or different and represent -H, -F, an alkyl group, or a fluoroalkyl group. The alkyl group is an alkyl group that does not contain a fluorine atom, and may have one or more carbon atoms. The alkyl group preferably has six or fewer carbon atoms, more preferably four or fewer carbon atoms, and even more preferably three or fewer carbon atoms. The fluorine-containing alkyl group is an alkyl group that contains at least one fluorine atom, and may have one or more carbon atoms. The fluorine-containing alkyl group preferably has six or fewer carbon atoms, more preferably four or fewer carbon atoms, and even more preferably three or fewer carbon atoms. Z's are preferably -H, -F, or -CF3, and more preferably -F.

[0094] In general formula (5), it is preferable that at least one of X, Y, and Z contains a fluorine atom. For example, X may be —H, and Y and Z may be —F.

[0095] In general formula (5), Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms, or a fluorine-containing alkylene group having 2 to 100 carbon atoms and an ether bond. The fluorine-containing alkylene group preferably has 2 or more carbon atoms. The fluorine-containing alkylene group preferably has 30 or less carbon atoms, more preferably 20 or less, and even more preferably 10 or less carbon atoms. Examples of the fluorine-containing alkylene group include -CF2-, -CH2CF2-, -CF2CF2-, -CF2CH2-, -CF2CF2CH2-, -CF(CF3)-, -CF(CF3)CF2-, and -CF(CF3)CH2-. The fluorine-containing alkylene group is preferably a perfluoroalkylene group.

[0096] The carbon number of the fluorine-containing alkylene group having an ether bond is preferably 3 or more. The carbon number of the fluorine-containing alkylene group having an ether bond is preferably 60 or less, more preferably 30 or less, and even more preferably 12 or less.

[0097] Examples of the fluorine-containing alkylene group having an ether bond include a group represented by the following formula: [ka] (In the formula, Z 1 is F or CF3;Z 2 and Z 3 are H or F;Z respectively 4 is also preferably a divalent group represented by the formula: H, F, or CF3; p1+q1+r1 is an integer of 1 to 10; s1 is 0 or 1; and t1 is an integer of 0 to 5).

[0098] Specific examples of the fluorine-containing alkylene group having an ether bond include -CF(CF3)CF2-O-CF(CF3)- and -(CF(CF3)CF2-O) n -CF(CF3)- (wherein n is an integer of 1 to 10), -CF(CF3)CF2-O-CF(CF3)CH2-, -(CF(CF3)CF2-O) n Examples include -CF(CF3)CH2- (wherein n is an integer of 1 to 10), -CH2CF2CF2O-CH2CF2CH2-, -CF2CF2CF2O-CF2CF2-, -CF2CF2CF2O-CF2CF2CH2-, -CF2CF2O-CF2-, -CF2CF2O-CF2CH2-, etc. The fluorine-containing alkylene group having an ether bond is preferably a perfluoroalkylene group.

[0099] In the general formula (5), Y 3 is -COOM, -SO3M or -OSO3M (M is H, a metal atom, NR 7 4. An imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent, R 7are H or organic groups and may be the same or different. Any two of them may be bonded to each other to form a ring.

[0100] R 7 The organic group in R is preferably an alkyl group. 7 As for H or C 1-10 is preferably an organic group represented by the formula: 1-4 The organic group is more preferably H or C 1-4 The alkyl group represented by the formula (I) is more preferred. The metal atom includes alkali metals (Group 1) and alkaline earth metals (Group 2), and Na, K, or Li is preferred. M represents -H, a metal atom, or -NR 7 4 is preferred, and -H, an alkali metal (Group 1), an alkaline earth metal (Group 2) or -NR 7 Y is more preferred, -H, -Na, -K, -Li or -NH is even more preferred, -Na, -K or -NH is even more preferred, -Na or -NH is particularly preferred, and -NH is most preferred. 3 As the alkyl group, -COOM or -SO3M is preferred, and -COOM is more preferred.

[0101] The compound represented by general formula (5) is preferably a compound (5a) represented by general formula (5a). CH2=CF(-CF2-O-Rf-Y 3 ) (5a) (Wherein Rf and Y 3 is the same as above.)

[0102] Specific examples of the compound represented by general formula (5a) include compounds represented by the following formula:

[0103] [ka]

[0104] (In the formula, Z 1 is F or CF3;Z 2 and Z 3 are H or F;Z respectively 4is H, F, or CF3; p1+q1+r1 are integers between 0 and 10; s1 is 0 or 1; t1 is an integer between 0 and 5; Y 3 is the same as above, except for Z 3 and Z 4 are both H, then p1+q1+r1+s1 is not 0). More specifically, compounds represented by the following formula are included:

[0105] [ka]

[0106] Among them,

[0107] [ka]

[0108] It is preferable that:

[0109] The compound represented by general formula (5a) includes compounds represented by formula (5a) 3 is preferably -COOM, and particularly preferably at least one selected from the group consisting of CH2=CFCF2OCF(CF3)COOM and CH2=CFCF2OCF(CF3)CF2OCF(CF3)COOM (wherein M is as defined above), and more preferably CH2=CFCF2OCF(CF3)COOM.

[0110] The compound represented by general formula (5) is preferably a compound (5b) represented by general formula (5b). CX 2 2=CFCF2-O-(CF(CF3)CF2O) n5 -CF(CF3)-Y 3 (5b) (In the formula, each 2 are the same and represent F or H. n5 represents 0 or an integer of 1 to 10, and Y 3 is the same as the definition above.)

[0111] In the general formula (5b), n5 is preferably 0 or an integer of 1 to 5, more preferably 0, 1 or 2, and even more preferably 0 or 1, in terms of the stability of the resulting aqueous dispersion. 3 is preferably -COOM in that it provides adequate water solubility and stability of the aqueous dispersion, and M is preferably H or NH4 in that it is less likely to remain as an impurity and the heat resistance of the resulting molded article is improved.

[0112] Examples of the compound represented by general formula (5b) include CH2=CFCF2OCF(CF3)COOM and CH2=CFCF2OCF(CF3)CF2OCF(CF3)COOM (wherein M is as defined above).

[0113] Further, examples of the compound represented by the general formula (5) include the compound (5c) represented by the general formula (5c). CF2=CFCF2-O-Rf-Y 3 (5c) (Wherein Rf and Y 3 is the same as above)

[0114] More specifically, [ka] etc.

[0115] In general formula (6), X is -H or -F. Both Xs may be -F, or at least one X may be -H. For example, one X may be -F and the other may be -H, or both Xs may be -H.

[0116] In general formula (6), Y is -H, -F, an alkyl group, or a fluorine-containing alkyl group. The alkyl group is an alkyl group that does not contain a fluorine atom, and may have one or more carbon atoms. The alkyl group preferably has six or fewer carbon atoms, more preferably four or fewer carbon atoms, and even more preferably three or fewer carbon atoms. The fluorine-containing alkyl group is an alkyl group that contains at least one fluorine atom, and may have one or more carbon atoms. The fluorine-containing alkyl group preferably has six or fewer carbon atoms, more preferably four or fewer carbon atoms, and even more preferably three or fewer carbon atoms. Y is preferably -H, -F, or -CF3, and more preferably -F.

[0117] In general formula (6), it is preferable that at least one of X and Y contains a fluorine atom. For example, X may be —H, and Y and Z may be —F.

[0118] In general formula (6), Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms, or a fluorine-containing alkylene group having 2 to 100 carbon atoms and an ether bond. The fluorine-containing alkylene group preferably has 2 or more carbon atoms. The fluorine-containing alkylene group preferably has 30 or less carbon atoms, more preferably 20 or less, and even more preferably 10 or less carbon atoms. Examples of the fluorine-containing alkylene group include -CF2-, -CH2CF2-, -CF2CF2-, -CF2CH2-, -CF2CF2CH2-, -CF(CF3)-, -CF(CF3)CF2-, and -CF(CF3)CH2-. The fluorine-containing alkylene group is preferably a perfluoroalkylene group.

[0119] In the above general formula (6), Y 3 is -COOM, -SO3M or -OSO3M (M is H, a metal atom, NR 7 4. An imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent, R 7 are H or organic groups and may be the same or different. Any two of them may be bonded to each other to form a ring.

[0120] R 7The organic group in R is preferably an alkyl group. 7 As for H or C 1-10 is preferably an organic group represented by the formula: 1-4 The organic group is more preferably H or C 1-4 The above-mentioned alkyl group is more preferred. The metal atom includes alkali metals (Group 1) and alkaline earth metals (Group 2), and Na, K, or Li is preferred. The above-mentioned M is -H, a metal atom, or -NR 7 4 is preferred, and -H, an alkali metal (Group 1), an alkaline earth metal (Group 2) or -NR 7 4 is more preferred, -H, -Na, -K, -Li or -NH4 is even more preferred, -Na, -K or -NH4 is even more preferred, -Na or -NH4 is particularly preferred, and -NH4 is most preferred. 3 As the alkyl group, -COOM or -SO3M is preferred, and -COOM is more preferred.

[0121] The compound represented by general formula (6) is preferably at least one selected from the group consisting of compounds represented by general formulas (6a) to (6f). CF2=CF-O-(CF2) n1 -Y 3 (6a) (wherein n1 represents an integer of 1 to 10, and Y 3 is the same as the definition above) CF2=CF-O-(CF2C(CF3)F) n2 -Y 3 (6b) (wherein n2 represents an integer of 1 to 5, and Y 3 is the same as the definition above.) CF2=CF-O-(CFX 1 ) n3 -Y 3 (6c) (In the formula, X 1 represents F or CF3, n3 represents an integer of 1 to 10, and Y 3 is the same as the definition above.) CF2=CF-O-(CF2CFX 1 O) n4 -(CF2) n6 -Y 3 (6d) (wherein n4 represents an integer of 1 to 10, n6 represents an integer of 1 to 3, and Y 3 and X 1 is the same as the definition above.) CF2=CF-O-(CF2CF2CFX 1 O) n5 -CF2CF2CF2-Y 3 (6e) (wherein n5 represents an integer of 0 to 10, and Y 3 and X 1 is the same as the definition above.) CF2=CF-O(-CF2) n6 -O-CF2-Y 3 (6f) (wherein n6 represents an integer of 1 to 6, and Y 3 and X 1 is the same as the definition above.)

[0122] In the general formula (6a), n1 is preferably an integer of 5 or less, and more preferably an integer of 2 or less. Y 3 is preferably -COOM or -SO3M in that it provides suitable water solubility and stability of the aqueous dispersion, and M is preferably Na, H or NH4 because it is easy to synthesize, and is preferably H or NH4 because it is less likely to remain as an impurity and the heat resistance of the resulting molded article is improved.

[0123] Examples of compounds represented by general formula (6a) include CF2=CF-O-CF2COOM, CF2=CF(OCF2CF2COOM), CF2=CF(OCF2CF2CF2COOM), CF2=CF(OCF2CF2SO3M), CF2=CF(OCF2SO3M), and CF2=CF(OCF2CF2CF2SO3M) (wherein M is as defined above).

[0124] In the general formula (6b), n2 is preferably an integer of 3 or less in terms of the stability of the resulting aqueous dispersion, and Y 3is preferably -COOM or -SO3M in that it provides suitable water solubility and stability of the aqueous dispersion, and M is preferably H or NH4 in that it is less likely to remain as an impurity and the heat resistance of the resulting molded article is improved.

[0125] In the general formula (6c), n3 is preferably an integer of 5 or less in terms of water solubility, and Y 3 is preferably —COOM or —SO3M in that it provides suitable water solubility and stability of the aqueous dispersion, and M is preferably Na, H or NH4 in that it provides good dispersion stability.

[0126] In general formula (6d), X 1 is preferably —CF3 in terms of the stability of the aqueous dispersion, n4 is preferably an integer of 5 or less in terms of water solubility, and Y 3 is preferably —COOM or —SO3M in that it provides suitable water solubility and stability of the aqueous dispersion, and M is preferably Na, H or NH4.

[0127] Examples of compounds represented by general formula (6d) include CF2=CFOCF2CF(CF3)OCF2CF2COOM, CF2=CFOCF2CF(CF3)OCF2COOM, CF2=CFOCF2CF(CF3)OCF2CF2CF2COOM, CF2=CFOCF2CF(CF3)OCF2CF2CF2COOM, CF2=CFOCF2CF(CF3)OCF2SO3M, CF2=CFOCF2CF(CF3)OCF2CF2SO3M, CF2=CFOCF2CF(CF3)OCF2CF2CF2SO3M (wherein M represents H, NH4, or an alkali metal).

[0128] In the general formula (6e), n5 is preferably an integer of 5 or less in terms of water solubility, and Y 3 is preferably -COOM in that it provides suitable water solubility and stability of the aqueous dispersion, and M is preferably Na, H or NH4.

[0129] An example of the compound represented by general formula (6e) is CF2=CFOCF2CF2CF2COOM (wherein M represents H, NH4 or an alkali metal).

[0130] An example of the compound represented by general formula (6f) is CF2=CFOCF2CF2CF2OCF2COOM (wherein M represents H, NH4 or an alkali metal).

[0131] In general formula (7), Rf is preferably a fluorine-containing alkylene group having a carbon number of 1 to 40. In general formula (7), at least one of X and Y preferably contains a fluorine atom.

[0132] The compound represented by general formula (7) is represented by general formula (7a): CF2=CF-(CF2) n1 -Y 3 (7a) (wherein n1 represents an integer of 1 to 10, and Y 3 is as defined above.) and a compound represented by general formula (7b): CF2=CF-(CF2C(CF3)F) n2 -Y 3 (7b) (wherein n2 represents an integer of 1 to 5, and Y 3 is as defined above. Preferably, at least one compound selected from the group consisting of compounds represented by

[0133] Y in general formula (7) 3 is preferably -SO3M or -COOM, and M is H, a metal atom, NR 7 4. It is preferably an imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent. 7 represents H or an organic group.

[0134] In the general formula (7a), n1 is preferably an integer of 5 or less, and more preferably an integer of 2 or less. Y 3is preferably -COOM in that it provides suitable water solubility and stability of the aqueous dispersion, and M is preferably H or NH4 in that it is less likely to remain as an impurity and the heat resistance of the resulting molded article is improved.

[0135] An example of the compound represented by general formula (7a) is CF2=CFCF2COOM (wherein M is as defined above).

[0136] In the general formula (7b), n2 is preferably an integer of 3 or less in terms of the stability of the resulting aqueous dispersion, and Y 3 is preferably -COOM in that it provides suitable water solubility and stability of the aqueous dispersion, and M is preferably H or NH4 in that it is less likely to remain as an impurity and the heat resistance of the resulting molded article is improved.

[0137] The fluorine-containing compound (A0) is preferably at least one selected from the group consisting of compounds represented by general formula (5), compounds represented by general formula (6), and compounds represented by general formula (7), more preferably at least one selected from the group consisting of compounds represented by general formula (5) and compounds represented by general formula (6), and even more preferably the compound represented by general formula (5), since a large number of fluorine-containing elastomer particles can be generated at the initial stage of the polymerization reaction.

[0138] The compound represented by general formula (5) is preferably at least one selected from the group consisting of compounds represented by general formula (5a), compounds represented by general formula (5b), and compounds represented by general formula (5c). Of these, at least one selected from the group consisting of compounds represented by general formula (5a) and compounds represented by general formula (5b) is more preferred, and compounds represented by general formula (5a) are even more preferred.

[0139] The amount of the fluorine-containing compound (A0) used in polymerizing the fluorine-containing monomer is preferably 3 to 5,000 ppm by mass, more preferably 5 ppm by mass or more, even more preferably 10 ppm by mass or more, particularly preferably 20 ppm by mass or more, and most preferably 30 ppm by mass or more, and more preferably 1,000 ppm by mass or less, even more preferably 500 ppm by mass or less, particularly preferably 200 ppm by mass or less, and most preferably 100 ppm by mass or less, based on the aqueous medium. By setting the amount of the fluorine-containing compound (A0) within the above range, a larger amount of fluorine-containing elastomer particles can be generated, and adhesion of the fluorine-containing elastomer to the polymerization vessel can be further suppressed.

[0140] It is also preferred to adjust the amount of the fluorine-containing compound (A0) depending on the type of polymerization initiator used in the polymerization and the polymerization temperature. When a non-redox polymerization initiator is used as the polymerization initiator and polymerization is carried out at 40 to 70°C, the amount of the fluorine-containing compound (A0) is preferably 3 to 300 ppm by mass, more preferably 3 to 150 ppm by mass, still more preferably 5 to 100 ppm by mass, and most preferably 8 to 80 ppm by mass, relative to the aqueous medium. When a non-redox polymerization initiator is used as the polymerization initiator and polymerization is carried out at more than 70°C and not more than 98°C, the amount of the fluorine-containing compound (A0) is preferably from 3 to 500 ppm by mass, more preferably from 3 to 200 ppm by mass, still more preferably from 5 to 120 ppm by mass, and most preferably from 20 to 110 ppm by mass, relative to the aqueous medium. When a redox polymerization initiator is used as the polymerization initiator and polymerization is carried out at 10°C or higher and lower than 40°C, the amount of the fluorine-containing compound (A0) is preferably from 3 to 300 ppm by mass, more preferably from 3 to 100 ppm by mass, still more preferably from 5 to 80 ppm by mass, and most preferably from 10 to 70 ppm by mass, relative to the aqueous medium. When a redox polymerization initiator is used as the polymerization initiator and polymerization is carried out at 40 to 70°C, the amount of the fluorine-containing compound (A0) is preferably 3 to 500 ppm by mass, more preferably 5 to 300 ppm by mass, still more preferably 10 to 200 ppm by mass, and most preferably 15 to 150 ppm by mass, relative to the aqueous medium. When a redox polymerization initiator is used as the polymerization initiator and polymerization is carried out at more than 70°C and not more than 98°C, the amount of the fluorine-containing compound (A0) is preferably from 5 to 500 ppm by mass, more preferably from 8 to 300 ppm by mass, still more preferably from 15 to 200 ppm by mass, and most preferably from 20 to 150 ppm by mass, relative to the aqueous medium. When the amount of the fluorine-containing compound (A0) is within the above range, the adhesion rate can be further reduced and the polymerization time can be shortened.

[0141] The fluorine-containing compound (A0) is preferably added before the polymerization initiator is added to start the polymerization reaction, and is preferably added only before the polymerization reaction starts, and not added after the start of polymerization.

[0142] The compound (A1) is a compound having one or more triple bonds and one or more hydrophilic groups in the molecule.

[0143] The triple bond is preferably a carbon-carbon triple bond. The number of triple bonds in the compound (A1) is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1.

[0144] Examples of the hydrophilic group include anionic hydrophilic groups, cationic hydrophilic groups, and nonionic hydrophilic groups. Compound (A1) may have only anionic hydrophilic groups, or only nonionic hydrophilic groups. Compound (A1) is preferably a compound (A1) having a triple bond and an anionic hydrophilic group.

[0145] As the hydrophilic group, for example, anionic hydrophilic groups are preferred, since they can generate more fluorine-containing elastomer particles and can further suppress adhesion of the fluorine-containing elastomer to the polymerization vessel, and examples thereof include -COOM, -SO3M, -OSO3M, and -B(OM)(OR 2 ), -OB(OM)(OR 2 ), -PO(OM)(OR 2 ), or -OPO(OM)(OR 2 M is H, a metal atom, NR 3 4. An imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent. 3 R is the same or different in each occurrence and is H or an organic group. 2 is H, metal atom, NR 3 4. An imidazolium which may have a substituent, a pyridinium which may have a substituent, a phosphonium which may have a substituent, or an alkynyl group.

[0146] M is H, a metal atom, or NR 3 4 is preferred, H, an alkali metal (Group 1), an alkaline earth metal (Group 2) or NR 3 4 is more preferred, H, Na, K, Li or NH4 is even more preferred, and H, Na, K or NH4 is especially preferred.

[0147] The number of hydrophilic groups in the compound (A1) is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1.

[0148] The number of carbon atoms in the compound (A1) is preferably 2 to 25, more preferably 2 to 10, still more preferably 2 to 6, and particularly preferably 2 to 4, since a larger number of fluorine-containing elastomer particles can be generated and adhesion of the fluorine-containing elastomer to the polymerization vessel can be further suppressed. In the present disclosure, the number of carbon atoms in the compound (A1) does not include the number of carbon atoms in carboxylic acid groups and carboxylate salt groups that may be contained in the compound (A1).

[0149] The compound (A1) is preferably a compound that does not contain fluorine.

[0150] In the production method of the present disclosure, one or more compounds (A1) may be used. As the compound (A1), only a compound having an anionic hydrophilic group may be used, only a compound having a nonionic hydrophilic group may be used, or a compound containing an anionic hydrophilic group and a compound containing a nonionic hydrophilic group may be used in combination.

[0151] The compound (A1) is preferably a compound (A1) represented by general formula (A1). General formula (A1):A 1 -R 1 -C≡CX 1 (In the formula: A 1 -COOM, -SO3M, -OSO3M, -B(OM)(OR 2 ), -OB(OM)(OR 2 ), -PO(OM)(OR 2 ), or -OPO(OM)(OR 2 ) and M is H, a metal atom, NR 3 4. optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium; R 3 is the same or different in each occurrence and is H or an organic group; R 2 is H, metal atom, NR 3 4. optionally substituted imidazolium, optionally substituted pyridinium, optionally substituted phosphonium, or alkynyl group; R 1 is a single bond or a divalent hydrocarbon group which may have a halogen atom; X 1 H, A 1 or a hydrocarbon group which may have a halogen atom, an ether bond, an ester bond or an amide bond.

[0152] In general formula (A1), A 1-COOM, -SO3M, -OSO3M, -B(OM)(OR 2 ), -OB(OM)(OR 2 ), -PO(OM)(OR 2 ), or -OPO(OM)(OR 2 ) where M is H, a metal atom, or NR 3 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 3 is the same or different in each occurrence and is H or an organic group; R 2 is H, metal atom, NR 3 4. An imidazolium which may have a substituent, a pyridinium which may have a substituent, a phosphonium which may have a substituent, or an alkynyl group.

[0153] A 1 As the catalyst, -COOM is preferred because it can generate a larger amount of fluorine-containing elastomer particles and can further suppress adhesion of the fluorine-containing elastomer to the polymerization vessel.

[0154] A 1 In the formula, M is preferably H, a metal atom, or NR, since it can generate more fluorine-containing elastomer particles and can further suppress adhesion of the fluorine-containing elastomer to the polymerization vessel. 3 4 is preferred, H, an alkali metal (Group 1), an alkaline earth metal (Group 2) or NR 3 4 is more preferred, H, Na, K, Li or NH4 is even more preferred, and H, Na, K or NH4 is especially preferred.

[0155] R 2 The alkynyl group of R is preferably an alkynyl group containing no fluorine atom. 2 The alkynyl group is preferably an ethynyl group which may be substituted with an alkyl group having 1 to 5 carbon atoms, and more preferably an unsubstituted ethynyl group.

[0156] R 2The group may be H, a metal atom, or NR 3 4 is preferred, H, an alkali metal (Group 1), an alkaline earth metal (Group 2) or NR 3 4 is more preferred, H, Na, K, Li or NH4 is even more preferred, H, Na, K or NH4 is especially preferred, and H is most preferred.

[0157] A 1 -PO(OM)(OR 2 ) or -OPO(OM)(OR 2 ), then R 2 is also a preferred embodiment in which is an ethynyl group.

[0158] In general formula (A1), R 1 is a single bond or a divalent hydrocarbon group which may have a halogen atom.

[0159] In general formula (A1), R 1 Examples of the divalent hydrocarbon group include a linear or branched alkanediyl group, a linear or branched alkenediyl group, a linear or branched alkadienediyl group, and a cycloalkanediyl group.

[0160] R 1 The halogen atom that may be contained in is preferably F, Cl, Br or I, and more preferably Cl, Br or I.

[0161] R 1 As the alkyl group, a single bond or a linear or branched alkanediyl group having 1 to 5 carbon atoms which may have a halogen atom is preferred, a single bond, a methylene group or an ethylene group is more preferred, a single bond or a methylene group is further preferred, and a single bond is particularly preferred, because it can generate a larger amount of fluorine-containing elastomer particles and can further suppress adhesion of the fluorine-containing elastomer to the polymerization vessel.

[0162] R 1The number of carbon atoms is preferably 0 to 20, more preferably 0 to 10, further preferably 0 to 5, and particularly preferably 0 to 3.

[0163] In general formula (A1), X 1 H, A 1 or a hydrocarbon group which may have a halogen atom, an ether bond, an ester bond or an amide bond. 1 is as described above.

[0164] X 1 Examples of the hydrocarbon group of X include an alkyl group which may have an aromatic group or a cycloalkyl group, an alkenyl group which may have an aromatic group or a cycloalkyl group, a cycloalkyl group which may have an aromatic group, and an aromatic group which may have an alkyl group. 1 and the alkyl group X 1 The alkenyl group of X is linear or branched. 1 and the cycloalkyl group X 1 The aromatic group, which may have an alkyl group, is monocyclic or polycyclic.

[0165] X 1 The halogen atom that may be contained in is preferably F, Cl, Br or I, and more preferably Cl, Br or I.

[0166] X 1 The hydrocarbon group preferably has 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, further preferably 1 to 5 carbon atoms, and particularly preferably 1 to 3 carbon atoms.

[0167] X 1 As the fluorine-containing elastomer, H, an alkyl group having 1 to 5 carbon atoms which may have a halogen atom, or A is preferred because it can generate more fluorine-containing elastomer particles and can further suppress adhesion of the fluorine-containing elastomer to the polymerization vessel. 1 is preferred, and H or A 1 is more preferred, H, —SO3M or —COOM is even more preferred, and H or —COOM is particularly preferred.

[0168] X 1 A 1 If X 1 is -COOM, -SO3M, -OSO3M, -B(OM)2, -OB(OM)2, -PO(OM)2, or -OPO(OM)2, M represents H, a metal atom, or NR 3 4 is preferred, H, an alkali metal (Group 1), an alkaline earth metal (Group 2) or NR 3 4 is more preferred, H, Na, K, Li or NH4 is even more preferred, H, Na, K or NH4 is especially preferred, and H is most preferred.

[0169] An example of the compound (A1) is a compound (A1-1) represented by general formula (A1-1). General formula (A1-1):A 1 -R 1 -C≡CA 1 (In the formula, R 1 and A 1 are as above and may be the same or different in each occurrence.)

[0170] Compound (A1-1) is a compound having two A 1 Including A 1 contains one M, and therefore the compound (A1-1) contains two M. As the compound (A1-1), one in which only one of the two Ms is H is preferred.

[0171] More specifically, the compound (A1-1) includes compounds represented by the following general formula: MOOC-R 1 -C≡C-COOM MO3S-R 1 -C≡C-SO3M MO3SO-R 1 -C≡C-OSO3M (R 2 O)(MO)BR 1 -C≡CB(OM)(OR 2 ) (R 2O)(MO)BO-R 1 -C≡C-OB(OM)(OR 2 ) (R 2 O)(MO)OP-R 1 -C≡C-PO(OM)(OR 2 ) (R 2 O)(MO)OPO-R 1 -C≡C-OPO(OM)(OR 2 ) (In the formula, R 1 ,M,and ,R 2 are as defined above and may be the same or different in each occurrence.)

[0172] Among them, the compound (A1-1) is preferably a compound represented by the general formula: MOOC-R 1 -C≡C-COOM (In the formula, R 1 and M is as defined above and may be the same or different in each occurrence. A compound represented by the following formula is preferred.

[0173] An example of the compound (A1) is a compound (A1-2) represented by general formula (A1-2). General formula (A1-2):A 1 -R 1 -C≡CR 4 (In the formula, A 1 and R 1 is as above, and R 4 is H or a hydrocarbon group which may have a halogen atom, an ether bond, an ester bond or an amide bond.

[0174] In general formula (A1-2), R 4 is H or a hydrocarbon group which may have a halogen atom, an ether bond, an ester bond or an amide bond.

[0175] R 4Examples of the hydrocarbon group of R include an alkyl group which may have an aromatic group or a cycloalkyl group, an alkenyl group which may have an aromatic group or a cycloalkyl group, a cycloalkyl group which may have an aromatic group, and an aromatic group which may have an alkyl group. 4 The alkyl group and R 4 The alkenyl group in R is linear or branched. 4 and R 4 The aromatic group, which may have an alkyl group, is monocyclic or polycyclic.

[0176] R 4 The halogen atom that may be contained in the hydrocarbon group is preferably F, Cl, Br or I, and more preferably Cl, Br or I.

[0177] R 4 The hydrocarbon group preferably has 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, further preferably 1 to 5 carbon atoms, and particularly preferably 1 to 3 carbon atoms.

[0178] R 4 As the alkyl group, H or an alkyl group having 1 to 20 carbon atoms is preferred, H or an alkyl group having 1 to 10 carbon atoms is more preferred, H or an alkyl group having 1 to 5 carbon atoms is still more preferred, H or an alkyl group having 1 to 3 carbon atoms is particularly preferred, and H is most preferred, because this allows the generation of a larger amount of fluorine-containing elastomer particles and further suppresses the adhesion of the fluorine-containing elastomer to the polymerization vessel.

[0179] Among them, the compound (A1-2) is preferably a compound represented by the general formula: MOOC-R 1 -C≡CR 4 (In the formula, R 1 , R 4 and M is as defined above and may be the same or different in each occurrence. A compound represented by the following formula is preferred.

[0180] Examples of the compound (A1) include: acetylene sulfonic acid, propiolic acid, ethynyl hydrogen sulfate, undec-10-ynyl hydrogen sulfate, but-3-ynyl hydrogen sulfate, prop-2-ynyl hydrogen sulfate, pent-4-ynyl hydrogen sulfate, 5-methyl-1-hexyn-3-yl hydrogen sulfate, ethynylboronic acid, ethynyl dihydrogen phosphate, Diethynyl hydrogen phosphate, acetylenedisulfonic acid, acetylenedicarboxylic acid, 1-propynylsulfonic acid, 2-phenyl-1-ethynylsulfonic acid, hex-1-yn-1-sulfonic acid, hexadec-1-yn-1-sulfonic acid, 3,3-dimethyl-1-butynesulfonic acid, 2-cyclopropyl-1-ethynesulfonic acid, 3-methoxy-1-propynylsulfonic acid, 3-phenoxy-1-propynylsulfonic acid, hept-2-yneoic acid, 6-phenylhex-2-ynoic acid, 3-cyclopropyl-2-propanoic acid, cyclohexylpropiolic acid, 3-cyclopentyl-2-propynoic acid, but-2-yneoic acid, undeca-2,4-dien-6-ynoic acid, 3-(cyclohepta-2,4,6-trien-1-yl)propanoic acid, 6-(fluoren-9-yl)hex-2-ynoic acid, 6-cyclohexyl-hex-2-ynoic acid, pent-3-ynoic acid, 4-phenyl-3-butynoic acid, 4-(4-methylphenyl)-3-butynoic acid, 4-p-chlorophenyl-3-butynoic acid, 4-p-bromophenyl-3-butynoic acid, 4-(4-fluorophenyl)-3-butynoic acid, 4-[4-(trifluoromethyl)phenyl]-3-butynoic acid, 4-(3-methylphenyl)-3-butynoic acid, 3-cyclopropyl-1-(1-carboxycyclopropyl)-1-propynoic acid, 4-(2-naphthalenyl)-3-butynoic acid, 4-cyclohexyl-3-propynoic acid, 5-phenylpent-1-ynoxyboronic acid, but-3-ene-1-ynoxyboronic acid, 2-phenylethynoxyboronic acid, 2-phenylethynyl phosphate, and salts thereof.

[0181] As the compound (A1), propiolic acid, acetylenedicarboxylic acid and salts thereof (for example, ammonium salt, sodium salt and potassium salt) are more preferred, since they can generate a larger amount of fluorine-containing elastomer particles and can further suppress adhesion of the fluorine-containing elastomer to the polymerization vessel.

[0182] The amount of compound (A1) used in polymerizing a fluorine-containing monomer is preferably 3 to 5,000 ppm by mass, more preferably 5 ppm by mass or more, even more preferably 10 ppm by mass or more, particularly preferably 20 ppm by mass or more, and most preferably 30 ppm by mass or more, and more preferably 1,000 ppm by mass or less, even more preferably 500 ppm by mass or less, particularly preferably 300 ppm by mass or less, and most preferably 200 ppm by mass or less, based on the aqueous medium. By setting the amount of compound (A1) within the above range, a larger amount of fluorine-containing elastomer particles can be generated, and adhesion of the fluorine-containing elastomer to the polymerization vessel can be further suppressed.

[0183] The fluorine-containing compound (A2) is a compound containing at least one fluorine atom in the molecule and is a compound represented by the general formula (A2). In the production method of the present disclosure, one or more types of fluorine-containing compounds (A2) may be used. General formula (A2):CX 1 X 2 =CX 3 -Z (In the formula:X 1 ~X 3 are each independently H, F or a fluorine-containing alkyl group; X 1 and X 2 If both are H, then X 3 is F or a fluorine-containing alkyl group; Z is a group represented by -COOM, -SO3M, -OSO3M, -PO(OM)2, -OPO(OM)2, -BO(OM)2 or -OBO(OM)2; M is H, a metal atom, NR 1 4. optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium; R 1 are independently H or an organic group, and R 1 Any two of may be bonded to each other to form a ring.)

[0184] In general formula (A2), X 1 ~X 3 are each independently H, F or a fluorine-containing alkyl group.

[0185] In general formula (A2), X 1 and X 2 are each independently preferably H or F, more preferably X 1 and X 2 are both H.

[0186] The fluorine-containing alkyl group is not particularly limited as long as it is an alkyl group containing at least one fluorine atom, and examples thereof include linear, branched, and cyclic fluorine-containing alkyl groups. 3 The fluorine-containing alkyl group X may contain an ether bond, an ester bond or an amide bond.3 The number of carbon atoms in the fluorine-containing alkyl group is preferably 1 or more, and preferably 20 or less, more preferably 10 or less, even more preferably 5 or less, and particularly preferably 3 or less.

[0187] X 1 and X 2 The fluorine-containing alkyl group is preferably CF3, CF2H or CFH2.

[0188] X 3 The fluorine-containing alkyl group is preferably CF3, CF2H or CFH2.

[0189] In general formula (A2), X 1 and X 2 If both are H, then X 3 is F or a fluorine-containing alkyl group. 3 is preferably F, CF3, CF2H or CFH2, more preferably F or CF3.

[0190] In general formula (A2), Z is a group represented by -COOM, -SO3M, -OSO3M, -PO(OM)2, -OPO(OM)2, -BO(OM)2 or -OBO(OM)2. Z is preferably -COOM, -SO3M or -OSO3M, more preferably -COOM, since it can generate a larger amount of fluorine-containing elastomer particles and can further suppress adhesion of the fluorine-containing elastomer to the polymerization vessel.

[0191] M is H, metal atom, NR 1 4. An imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent.

[0192] R 1 are independently H or an organic group, and R 1 Any two of these may be bonded to each other to form a ring. The organic group is preferably an alkyl group. 1 As for H or C 1-10is preferably an organic group represented by the formula: 1-4 The organic group is more preferably H or C 1-4 More preferred is an alkyl group of the formula (I), and most preferred is H.

[0193] The metal atom may be a monovalent or divalent metal atom, preferably an alkali metal (Group 1) or alkaline earth metal (Group 2), more preferably Na, K or Li.

[0194] As M, H, a metal atom or NR can be selected because it can generate a larger amount of fluorine-containing elastomer particles and can further suppress adhesion of the fluorine-containing elastomer to the polymerization vessel. 1 4 is preferred, H or NR 1 4 is more preferred, and H or NH4 is even more preferred.

[0195] As the fluorine-containing compound (A2), at least one selected from the group consisting of 2-trifluoromethylacrylic acid, α-fluoroacrylic acid, 3-fluoroacrylic acid, 2,3-difluoroacrylic acid, 3,3-difluoroacrylic acid, perfluoroacrylic acid, 3-trifluoromethylacrylic acid, 2-difluoromethylacrylic acid, 2-monofluoromethylacrylic acid, 3-monofluoromethylacrylic acid, 3-difluoromethylacrylic acid, and salts thereof is preferred, and at least one selected from the group consisting of 2-trifluoromethylacrylic acid and α-fluoroacrylic acid is more preferred, because it enables the generation of a larger amount of fluorine-containing elastomer particles and further suppresses the adhesion of the fluorine-containing elastomer to the polymerization vessel.

[0196] The amount of the fluorine-containing compound (A2) used in polymerizing the fluorine-containing monomer is preferably 3 to 5,000 ppm by mass, more preferably 5 ppm by mass or more, even more preferably 10 ppm by mass or more, particularly preferably 20 ppm by mass or more, and most preferably 30 ppm by mass or more, and more preferably 1,000 ppm by mass or less, even more preferably 500 ppm by mass or less, particularly preferably 300 ppm by mass or less, and most preferably 200 ppm by mass or less, based on the aqueous medium. By setting the amount of the fluorine-containing compound (A2) within the above range, a larger amount of fluorine-containing elastomer particles can be generated, and adhesion of the fluorine-containing elastomer to the polymerization vessel can be further suppressed.

[0197] The fluorine-free compound (A3) is a compound that does not contain a fluorine atom in the molecule and is a compound represented by the following general formula (A3): In the production method of the present disclosure, one or more types of the fluorine-free compound (A3) may be used. General formula (A3):CR 1 X 1 =CX 2 -R 2 -COOM (In the formula: R 1 is H or an alkyl group, said alkyl group may contain an ether bond, an ester bond or an amide bond; R 2 is a single bond or an alkylene group, and the alkylene group is such that at least one hydrogen atom bonded to a carbon atom is -R 3 -COOM(R 3 is a single bond or an alkylene group), and may contain an ether bond, an ester bond, an amide bond, an unsaturated bond or a cyclic structure; X 1 and X 2 are each independently -R 1 (R 1 as above) or -R 2 -COOM(R 2 is a group represented by the formula (1) as described above; M is H, a metal atom, NR 44. optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium; R 4 are independently H or an organic group, and R 4 Any two of may be bonded to each other to form a ring.)

[0198] The non-fluorine-containing compound (A3) is usually water-soluble, and the solubility of the non-fluorine-containing compound (A3) in water may be 0.1 g or more per 100 g of water.

[0199] In general formula (A3), R 1 is H or an alkyl group.

[0200] R 1 The alkyl group of R is not particularly limited as long as it is an alkyl group that does not contain a fluorine atom, and examples thereof include linear, branched, and cyclic alkyl groups. 1 The alkyl group of R may contain an ether bond, an ester bond, or an amide bond. 1 The number of carbon atoms in the alkyl group is preferably 1 or more, and preferably 20 or less, more preferably 10 or less, even more preferably 5 or less, and particularly preferably 3 or less.

[0201] R 1 The alkyl group R may have at least one hydrogen atom bonded to a carbon atom substituted with a substituent, but is preferably an unsubstituted alkyl group. 1 Examples of the alkyl group include -CH3, -CH2CH3, -CH2CH2CH3, -CH(CH3)CH3, -(CH2) y Examples include -CH3 (y is 3 to 19) and -COOCH3, and among these, -CH3 or -CH2CH3 is preferred, with -CH3 being more preferred.

[0202] In general formula (A3), R 2 is a single bond or an alkylene group. 2The alkylene group of R is not particularly limited as long as it is an alkylene group that does not contain a fluorine atom, and examples thereof include linear and branched alkylene groups. 2 The number of carbon atoms in the alkylene group is preferably 1 or more, and preferably 20 or less, more preferably 10 or less, even more preferably 5 or less, and particularly preferably 3 or less.

[0203] R 2 In the alkylene group, at least one hydrogen atom bonded to a carbon atom may be substituted with a substituent. In addition to the above-mentioned substituents, -R 3 Examples of such groups include groups represented by the formula -COOM. 2 The alkylene has -R 3 The number of groups represented by —COOM is preferably 1 to 3, and more preferably 1.

[0204] R 2 The alkylene group of R may contain an ether bond, an ester bond, an amide bond or an unsaturated bond. 2 The alkylene group may include a cyclic structure such as a cycloalkylene group which may contain an unsaturated bond.

[0205] R 2 Examples of the alkylene group include -CH2-, -CH2CH2-, -CH2CH2CH2-, -CH(CH3)CH2-, -CH2-C(CH3)2-, -(CH2) y -(y is 3~19), -CH2-CH(-COOM)-, -CH2-C(-CH3)(-COOM)-, -CH2-O-CH2-, -CH(-COOM)-CH2-, [ka] Among these, -CH2- or -CH2CH2- is preferred, and -CH2- is more preferred.

[0206] R 3 is a single bond or an alkylene group, preferably a single bond. 3The alkylene group of R is not particularly limited as long as it is an alkylene group that does not contain a fluorine atom, and examples thereof include linear and branched alkylene groups. 3 The number of carbon atoms in the alkylene group is preferably 1 or more, and preferably 20 or less, more preferably 10 or less, even more preferably 5 or less, and particularly preferably 3 or less.

[0207] R 3 In the alkylene group, at least one hydrogen atom bonded to a carbon atom may be substituted with a substituent. Examples of the substituent include those mentioned above.

[0208] R 3 The alkylene group of R may contain an ether bond, an ester bond, an amide bond or an unsaturated bond. 3 The alkylene group may include a cyclic structure such as a cycloalkylene group which may contain an unsaturated bond.

[0209] R 3 Examples of the alkylene group include -CH2-, -CH2CH2-, -CH2CH2CH2-, -CH(CH3)CH2-, and the like, and among these, -CH2- is preferred.

[0210] In general formula (A3), X 1 and X 2 are each independently -R 1 or -R 2 R is a group represented by -COOM. 1 , R 2 and M is as above.

[0211] M is H, metal atom, NR 4 4. An imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent.

[0212] R 4 are independently H or an organic group, and R 4Any two of these may be bonded to each other to form a ring. The organic group is preferably an alkyl group. 4 As for H or C 1-10 is preferably an organic group represented by the formula: 1-4 The organic group is more preferably H or C 1-4 More preferred is an alkyl group of the formula (I), and most preferred is H.

[0213] The metal atom may be a monovalent or divalent metal atom, preferably an alkali metal (Group 1) or alkaline earth metal (Group 2), more preferably Na, K or Li.

[0214] As M, H, a metal atom or NR can be selected because it can generate a larger amount of fluorine-containing elastomer particles and can further suppress adhesion of the fluorine-containing elastomer to the polymerization vessel. 4 4 is preferred, H or NR 4 4 is more preferred, and H or NH4 is even more preferred.

[0215] As the fluorine-free compound (A3), a fluorine-free compound represented by any of the following general formulas is preferred, since it can generate a larger amount of fluorine-containing elastomer particles and can further suppress adhesion of the fluorine-containing elastomer to the polymerization vessel: General formula (A3-1):CR 1 2=CR 1 -R 2 -COOM General formula (A3-2):CR 1 2=C(-R 2 -COOM)2 General formula (A3-3): MOCO-R 2 -CR 1 =CR 1 -R 2 -COOM General formula (A3-4): MOCO-R 2 -CR 1 =C(-R 2 -COOM)2 In general formulas (A3-1) to (A3-4), R 1 , R 2and M is as above.

[0216] Furthermore, as the fluorine-containing compound (A3), a fluorine-containing compound represented by general formula (A3-1-1) is preferred, since it is possible to generate a larger amount of fluorine-containing elastomer particles and to further suppress adhesion of the fluorine-containing elastomer to the polymerization vessel. General formula (A3-1-1): CH2=CH-R 2 -COOM In general formula (A3-1-1), R 2 and M is as above.

[0217] The number of carbon atoms in the fluorine-free compound (A3) is preferably 2 or more and 30 or less, more preferably 10 or less, still more preferably 5 or less, and particularly preferably 3 or less, since this enables the generation of a larger number of fluorine-containing elastomer particles and further suppresses the adhesion of the fluorine-containing elastomer to the polymerization vessel. In the present disclosure, the number of carbon atoms in the fluorine-free compound (A3) does not include the number of carbon atoms that may be contained in —COOM in the fluorine-free compound (A3).

[0218] Examples of the fluorine-free compound represented by general formula (A3-1) include: acrylic acid, methacrylic acid, crotonic acid, 2-butenoic acid (isocrotonic acid), 3-butenoic acid, 3-methylcrotonic acid, 2-methylisocrotonic acid (angelic acid), 4-pentenoic acid, 2-ethyl-2-butenoic acid, 2-nonenoic acid, 4-decenoic acid, 10-undecenoic acid, 4-undecenoic acid, tetradecenoic acid, cis-15-heptadecenoic acid, Heptadec-16-enoic acid, Henicos-20-enoic acid, Monomethyl fumarate, 2-allylmalonic acid, ethyl(prop-2-en-1-yl)propanedioate, (3-methyl-but-2-enyloxy)acetic acid, 2-allyl-3,3-dimethyl-1-cyclohexenecarboxylic acid, 2-allyl-1-cyclohexenecarboxylic acid, and their salts Examples include:

[0219] The fluorine-free compounds represented by general formula (A3-2) or general formula (A3-3) include: Itaconic acid, fumaric acid, Maleic acid, Methylmaleic acid (citraconic acid), Mesaconic acid, 2-pentenedioic acid, isopropylidenesuccinic acid, 2,2-dimethyl-4-methylidenepentanedioic acid, 1-butene-2,4-dicarboxylic acid, 3-butene-1,2,3-tricarboxylic acid, and their salts Examples include:

[0220] Examples of the fluorine-free compound represented by general formula (A3-4) include: (E)-1-propene-1,2,3-tricarboxylic acid, Ethenetricarboxylic acid, 3-pentene-1,3,4-tricarboxylic acid, and their salts Examples include:

[0221] Among these, the fluorine-free compound (A3) is preferably acrylic acid, 3-butenoic acid, or a salt thereof (for example, an ammonium salt, a sodium salt, or a potassium salt), since it can generate a larger amount of fluorine-containing elastomer particles and can further suppress adhesion of the fluorine-containing elastomer to the polymerization vessel.

[0222] The amount of the fluorine-free compound (A3) used in polymerizing the fluorine-containing monomer is preferably 3 to 5,000 ppm by mass, more preferably 5 ppm by mass or more, even more preferably 10 ppm by mass or more, particularly preferably 20 ppm by mass or more, and most preferably 30 ppm by mass or more, and more preferably 1,000 ppm by mass or less, even more preferably 500 ppm by mass or less, particularly preferably 300 ppm by mass or less, and most preferably 200 ppm by mass or less, based on the aqueous medium. By setting the amount of the fluorine-free compound (A3) within the above range, a larger amount of fluorine-containing elastomer particles can be generated, and adhesion of the fluorine-containing elastomer to the polymerization vessel can be further suppressed.

[0223] The compound (A4) has an aromatic ring, a hydrophilic group, and an unsaturated double bond.

[0224] In the present disclosure, the term "aromatic ring" refers to a cyclic structure having aromaticity, and includes monocyclic aromatic rings such as a benzene ring, fused aromatic rings such as a naphthalene ring, aromatic rings to which a phenyl group is bonded via a single bond such as a biphenyl ring, and heteroaromatic rings such as a furan ring.

[0225] The aromatic ring may be either a monocyclic or polycyclic ring, but is preferably a monocyclic ring. The number of aromatic rings contained in compound (A4) is preferably 1 to 5, more preferably 1 or 2, and even more preferably 1. The aromatic ring may be either a carbocyclic ring or a heterocyclic ring, but is preferably a carbocyclic ring.

[0226] The aromatic ring may have a substituent. That is, the aromatic ring may be a substituted or unsubstituted aromatic ring. Examples of the substituent include those mentioned above, and among them, a halogen atom, a hydroxy group, an alkyl group, a phenyl group, or a fluorophenyl group is preferred, and F, Cl, a hydroxy group, CH3, or a p-fluorophenyl group is more preferred.

[0227] Examples of the hydrophilic group include anionic hydrophilic groups, cationic hydrophilic groups, and nonionic hydrophilic groups. Compound (A4) may have only anionic hydrophilic groups, or only nonionic hydrophilic groups. The number of hydrophilic groups contained in compound (A4) may be 1 to 4, 1 to 3, 1 to 2, or 1.

[0228] The hydrophilic group is preferably -SO3M, -OSO3M, -COOM, -P(=O)(OM)2, -OP(O)(OM)2, -B(OM)2 or -OB(OM)2, and more preferably -SO3M, -OSO3M or -COOM, since this allows the generation of a larger amount of fluorine-containing elastomer particles and further suppresses adhesion of the fluorine-containing elastomer to the polymerization vessel.

[0229] M is H, metal atom, NR 6 4. An imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent.

[0230] R 6 are independently H or an organic group, and R 6 Any two of these may be bonded to each other to form a ring. The organic group is preferably an alkyl group. 6 As for H or C 1-10 is preferably an organic group represented by the formula: 1-4 The organic group is more preferably H or C 1-4 More preferred is an alkyl group of the formula (I), and most preferred is H.

[0231] The metal atom may be a monovalent or divalent metal atom, preferably an alkali metal (Group A4) or alkaline earth metal (Group 2), more preferably Na, K or Li.

[0232] As M, H, a metal atom or NR can be selected because it can generate a larger amount of fluorine-containing elastomer particles and can further suppress adhesion of the fluorine-containing elastomer to the polymerization vessel. 6 4 is preferred, H, Na, K or NR 6 4 is more preferred, and H, Na, K or NH4 is even more preferred.

[0233] The unsaturated double bond is preferably a radically polymerizable unsaturated double bond, which may be a vinyl bond.

[0234] The number of carbon atoms in the compound (A4) is preferably 6 to 80, more preferably 8 to 40, still more preferably 8 to 30, and particularly preferably 8 to 20, since a larger number of fluorine-containing elastomer particles can be generated and adhesion of the fluorine-containing elastomer to the polymerization vessel can be further suppressed. In the present disclosure, the number of carbon atoms in the compound (A4) does not include the number of carbon atoms in the hydrophilic group contained in the compound (A4).

[0235] The compound (A4) is preferably a compound that does not contain fluorine.

[0236] The compound (A4) is usually water-soluble, and the solubility of the compound (A4) in water may be 0.1 g or more per 100 g of water.

[0237] In the production method of the present disclosure, one or more compounds may be used as compound (A4). As compound (A4), only a compound having an anionic hydrophilic group may be used, only a compound having a nonionic hydrophilic group may be used, or a compound containing an anionic hydrophilic group and a compound containing a nonionic hydrophilic group may be used in combination.

[0238] The compound (A4) is preferably at least one compound selected from the group consisting of compounds represented by general formulas (A4-1) to (A4-4).

[0239] General formula (A4-1): [ka]

[0240] General formula (A4-2): [ka]

[0241] General formula (A4-3): [ka]

[0242] General formula (A4-4): [ka]

[0243] In general formulae (A4-1) to (A4-4), R 1 ~R 3 are each independently H, a halogen atom, an alkyl group, or -R 4 It is a group represented by -Z.

[0244] The alkyl group is not particularly limited, and examples thereof include linear, branched, and cyclic alkyl groups. When the alkyl group has two or more carbon atoms, the alkyl group may contain an ether bond. The number of carbon atoms in the alkyl group is preferably one or more, and preferably 20 or less, more preferably 10 or less, even more preferably 5 or less, and particularly preferably 3 or less.

[0245] In the alkyl group, at least one hydrogen atom bonded to a carbon atom may be substituted with a substituent. In addition to the above-mentioned substituents, examples of the substituent include -R 4 The compound (A4) has a group represented by -R. 4 The number of groups represented by -Z is preferably 1 or more, preferably 8 or less, more preferably 5 or less, even more preferably 4 or less, and particularly preferably 3 or less.

[0246] The alkyl group is preferably an alkyl group not containing a fluorine atom, and examples of the alkyl group include -CH, -CHCH, -CHCHCH, -CH(CH)CH, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl, with -CH being preferred.

[0247] The halogen atom is preferably F, Cl or Br, more preferably F.

[0248] R 1 ~R 3 Among these, H, F, -CH3, a cyclopropyl group, a cyclopentyl group, or a cyclohexyl group is preferable, and H, -CH3, a cyclopropyl group, a cyclopentyl group, or a cyclohexyl group is more preferable.

[0249] In general formulae (A4-1) to (A4-4), R 4 is a single bond or an alkylene group. Examples of the alkylene group include linear or branched alkylene groups. The number of carbon atoms in the alkylene group is preferably 1 or more and preferably 20 or less, more preferably 10 or less, and even more preferably 3 or less. The alkylene group is preferably -CH2-, -CH2CH2-, -CH2CH2CH2-, or -CH(CH3)CH2-, and more preferably -CH2-.

[0250] R 4 is preferably a single bond or -CH2-, more preferably a single bond.

[0251] In general formulae (A4-1) and (A4-4), R 5 is a single bond or an alkylene group. Examples of the alkylene group include linear or branched alkylene groups. The number of carbon atoms in the alkylene group is preferably 1 or more and preferably 20 or less, more preferably 10 or less, and even more preferably 3 or less. The alkylene group is preferably -CH2-, -CH2CH2-, -CH2CH2CH2-, or -CH(CH3)CH2-, and more preferably -CH2-.

[0252] R 5 is preferably a single bond or -CH2-, more preferably a single bond.

[0253] In the general formulae (A4-1) to (A4-4), Z is -SO3M, -OSO3M, -COOM, -P(=O)(OM)2, -OP(O)(OM)2, -B(OM)2, or -OB(OM)2. M and R 6 is as described above.

[0254] In general formulae (A4-1) and (A4-4), x represents -R bonded to ring A. 4 represents the number of groups represented by -Z, and is an integer of 1 or more. The upper limit of x may be equal to or less than the number of atoms forming all rings constituting ring A divided by 1, and is preferably 5 or less, more preferably 3 or less, and even more preferably 2 or less.

[0255] In the general formulae (A4-1) to (A4-4), ring A and ring B are aromatic rings which may have a substituent.

[0256] Ring A and ring B may be either monocyclic or polycyclic, but are preferably monocyclic. The number of aromatic rings contained in ring A and ring B is preferably 1 to 5, more preferably 1 or 2, and even more preferably 1. Ring A and ring B may be either carbocyclic or heterocyclic, but are preferably carbocyclic.

[0257] Ring A and ring B include Benzene ring, naphthalene ring, biphenyl ring, anthracene ring, furan ring, benzofuran ring, a pyrrole ring, an indole ring, an imidazole ring, a benzimidazole ring, a pyrazole ring, an indazole ring, a pyridine ring, a quinoline ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, a triazine ring, Thiophene ring, benzothiophene ring, an oxazole ring, a benzoxazole ring, Thiazole ring, benzothiazole ring and the like, all of which may be substituted with a substituent.

[0258] Examples of the substituents that ring A and ring B may have include -R 4 The substituent is not particularly limited as long as it is a group other than the group represented by -Z, and examples thereof include those mentioned above. Among them, a halogen atom, a hydroxy group, an alkyl group, a phenyl group, or a fluorophenyl group is preferred, and F, Cl, a hydroxy group, CH3, or a p-fluorophenyl group is more preferred.

[0259] As the ring A in the general formulae (A4-1) and (A4-4), a ring represented by any of the following formulae is preferred, since it enables the generation of a larger amount of fluorine-containing elastomer particles and further suppresses the adhesion of the fluorine-containing elastomer to the polymerization vessel:

[0260] [ka]

[0261] In the above formulas, the wavy lines represent carbon atoms constituting the vinyl group in the compounds represented by general formulas (A4-1) and (A4-4), R 5 or the carbon atom of the alkylene group of -R 4represents the bonding position of ring A to the group represented by -Z. In any aromatic ring, the hydrogen atom bonded to the carbon atom may be substituted with a substituent, or the hydrogen atom bonded to the carbon atom may not be substituted with a substituent. Examples of the substituent include those mentioned above, and among them, a halogen atom, a hydroxy group, an alkyl group, a phenyl group, or a fluorophenyl group is preferred, and F, Cl, a hydroxy group, CH3, or a p-fluorophenyl group is more preferred.

[0262] As the ring B in the general formulae (A4-2) to (A4-4), a ring represented by any of the following formulae is preferred, since it enables the generation of a larger amount of fluorine-containing elastomer particles and further suppresses the adhesion of the fluorine-containing elastomer to the polymerization vessel.

[0263] [ka]

[0264] In each of the above formulas, the wavy line represents the bonding position of ring B to the carbon atom constituting the vinyl group in the compounds represented by general formulas (A4-2) to (A4-4). In any of the aromatic rings, the hydrogen atom bonded to the carbon atom may be substituted with a substituent. Examples of the substituent include those mentioned above, and among them, a halogen atom, a hydroxy group, an alkyl group, a phenyl group, or a fluorophenyl group is preferred, and F, Cl, a hydroxy group, CH3, or a p-fluorophenyl group is more preferred.

[0265] The number of carbon atoms in compound (A4) is preferably 6 or more, more preferably 8 or more, and preferably 30 or less, more preferably 20 or less, still more preferably 12 or less, and particularly preferably 10 or less, because this enables the generation of a larger amount of fluorine-containing elastomer particles and further suppression of adhesion of the fluorine-containing elastomer to the polymerization vessel. In the present disclosure, the number of carbon atoms in compound (A4) does not include the number of carbon atoms that may be contained in Z in compound (A4).

[0266] Of the compounds (A4), those represented by general formulae (A4-1) to (A4-4) are particularly preferred.

[0267] Examples of the compound (A4) include: p-styrenesulfonic acid, 2-styrenesulfonic acid, m-styrenesulfonic acid, 4-(2-propenyl)benzoic acid, 4-vinylbenzoic acid, 4-(1-fluorovinyl)benzoic acid, 2-vinylphenylphosphonic acid (styrenephosphonic acid), 4-vinylphenylphosphonic acid (styrenephosphonic acid), 4-vinylbenzylphosphonic acid, 4-vinylphenyl sulfate, 2-(1-cyclopentylvinyl)benzoic acid, (E)-2-(2-cyclopentylvinyl)benzoic acid, 2-[(E)-2-cyclohexylvinyl)]benzoic acid, (E)-2-(3-(naphthalen-1-yl)allyl)benzoic acid, 1-cinnamyl-2-naphthoic acid, (Z)-2-(3-phenylallyl)benzoic acid, 3-allylnaphthalene-2-carboxylic acid, 4-ethenylbenzene-1,3-dicarboxylic acid, 4-vinylphenylboronic acid, 4-allyl-2,3,5,6-tetrafluorobenzoic acid, 2-allylbenzoic acid, 2-allyl-3-chlorobenzoic acid, 2-allyl-4-fluorobenzoic acid, 2-allyl-4-methylbenzoic acid, 2-allyl-5,6-dichlorobenzoic acid, 2-(allyl-3,3-d2)-6-fluorobenzoic acid, 4-vinylphthalic acid, 3-ethenylbenzene-1,2-dicarboxylic acid, 2-vinyl terephthalic acid, 5-vinylisophthalic acid, 4-vinylnaphthalene-1,2-dicarboxylic acid, 2-phenylacrylic acid, trans-cinnamic acid, 3-phenyl-2-butenoic acid, 3-methyl-4-phenyl-3-butenoic acid, trans-2-hydroxycinnamic acid, 5-vinyl-2-furan acid, 2-vinyl-3-furoic acid, 2-methyl-5-vinyl-3-furoic acid, 2-(4-fluorophenyl)-4-vinyl-2,5-dihydrofuran-3-carboxylic acid, 3,5-dimethyl-4-vinyl-1H-pyrrole-2-carboxylic acid, 2-vinyl-3-thiophenecarboxylic acid, 5-vinylpyridine-2-carboxylic acid, and their salts Examples include:

[0268] Of these, the compound (A4) is preferably p-styrenesulfonic acid, 4-vinylbenzoic acid, 4-vinylphenylboronic acid, or a salt thereof (for example, an ammonium salt, a sodium salt, or a potassium salt) because it can generate a larger amount of fluorine-containing elastomer particles and can further suppress adhesion of the fluorine-containing elastomer to the polymerization vessel.

[0269] The amount of compound (A4) used in polymerizing the fluorine-containing monomer is preferably 3 to 5,000 ppm by mass, more preferably 5 ppm by mass or more, even more preferably 10 ppm by mass or more, particularly preferably 20 ppm by mass or more, and most preferably 30 ppm by mass or more, and more preferably 1,000 ppm by mass or less, even more preferably 500 ppm by mass or less, particularly preferably 300 ppm by mass or less, and most preferably 200 ppm by mass or less, based on the aqueous medium. By setting the amount of compound (A4) within the above range, a larger amount of fluorine-containing elastomer particles can be generated, and adhesion of the fluorine-containing elastomer to the polymerization vessel can be further suppressed.

[0270] The non-fluorine-containing compound (A5) is a compound that does not contain a fluorine atom in the molecule and is a compound represented by the following general formula (A5): In the production method of the present disclosure, one or more types of non-fluorine-containing compounds (A5) may be used. General formula (A5):CX 1 X 2 =CX 3 -RZ (In the formula, X 1 , X 2 and X 3 are each independently H or an alkyl group; R is a single bond or an alkylene group; X 1 , X 2 , X 3 and the total number of carbon atoms in R is 0 to 5; Z is -SO3M, -OSO3M, -P(=O)(OM)2, -OP(O)(OM)2, or -B(OM)2; M is H, a metal atom, NR 1 4. optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium; R 1 are independently H or an organic group, and R 1 Any two of may be bonded to each other to form a ring.)

[0271] In general formula (A5), X 1 , X 2 and X 3are each independently H or an alkyl group. The alkyl group is not particularly limited as long as it is an alkyl group that does not contain a fluorine atom, and examples thereof include linear and branched alkyl groups. Examples of the alkyl group include -CH3, -CH2CH3, -CH2CH2CH3, and -CH(CH3)CH3, with -CH3 being preferred.

[0272] In general formula (A5), X 1 and X 2 In general formula (A5), X is preferably H. 3 As the alkyl group, -H or -CH3 is preferred, and -H is more preferred.

[0273] In general formula (A5), R is a single bond or an alkylene group. The alkylene group is not particularly limited as long as it does not contain a fluorine atom, and examples thereof include linear and branched alkylene groups. Examples of the alkylene group include -CH-, -CHCH-, -CHCHCH-, -CH(CH)CH-, etc., with -CH- being preferred.

[0274] In general formula (A5), R is preferably a single bond or -CH2-, and more preferably a single bond.

[0275] In general formula (A5), X 1 , X 2 , X 3 and the total number of carbon atoms in R is 0 to 5, preferably 0 to 4, more preferably 0 to 3, still more preferably 0 to 2, particularly preferably 0 or 1, and most preferably 0. If the total number of carbon atoms is too large, the amount of fluoropolymer adhering to the polymerization vessel increases or a sufficient number of fluoropolymer particles cannot be generated.

[0276] In general formula (A5), Z is -SO3M, -OSO3M, -P(=O)(OM)2, -OP(O)(OM)2 or -B(OM)2. Z is preferably -SO3M, -OSO3M or -P(=O)(OM)2, and more preferably -SO3M or -OSO3M, since it can generate a larger amount of fluorine-containing elastomer particles and can further suppress adhesion of the fluorine-containing elastomer to the polymerization vessel.

[0277] M is H, metal atom, NR 1 4. An imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent.

[0278] R 1 are independently H or an organic group, and R 1 Any two of these may be bonded to each other to form a ring. The organic group is preferably an alkyl group. 1 As for H or C 1-10 is preferably an organic group represented by the formula: 1-4 The organic group is more preferably H or C 1-4 More preferred is an alkyl group of the formula (I), and most preferred is H.

[0279] The metal atom may be a monovalent or divalent metal atom, preferably an alkali metal (Group 1) or alkaline earth metal (Group 2), more preferably Na, K or Li.

[0280] As M, H, a metal atom or NR can be selected because it can generate a larger amount of fluorine-containing elastomer particles and can further suppress adhesion of the fluorine-containing elastomer to the polymerization vessel. 1 4 is preferred, H, Na, K, Li or NR 1 4 is more preferred, Na, K, Li or NR 1 4 is more preferred, Na, K, Li or NH4 is especially preferred, and Na or NH4 is most preferred.

[0281] As the fluorine-free compound (A5), a fluorine-free compound represented by general formula (1-1) is preferred, since it can generate a larger amount of fluorine-containing elastomer particles and can further suppress adhesion of the fluorine-containing elastomer to the polymerization vessel. General formula (A5-1): CH2=CX 4 -R 2 -Z (In the formula, X 4 is H or CH3, and R 2 represents a single bond or an alkylene group having 1 to 3 carbon atoms, and Z is as defined above.

[0282] In general formula (A5-1), X 4 is preferably H. In addition, in general formula (A5-1), R 2 is preferably a single bond or -CH2-, more preferably a single bond.

[0283] Examples of the fluorine-free compound (A5) include: CH2=CHSO3M, CH2=CHCH2SO3M, CH2=C(CH3)CH2SO3M, CH2=C(CH3)SO3M, CH2=CHOSO3M, CH2=CHCH2OSO3M, CH2=C(CH3)CH2OSO3M, CH2=C(CH3)OSO3M, CH2=CHP(O)(OM)2, CH2=CHCH2P(O)(OM)2, CH2=C(CH3)CH2P(O)(OM)2, CH2=C(CH3)P(O)(OM)2, CH2=CHOP(O)(OM)2, CH2=CHCH2OP(O)(OM)2, CH2=C(CH3)CH2OP(O)(OM)2, CH2=C(CH3)OP(O)(OM)2, CH2=CHB(OM)2, CH2=CHCH2B(OM)2, CH2=C(CH3)CH2B(OM)2, or CH2=C(CH3)B(OM)2, is preferred, CH2=CHSO3M or CH2=CHCH2SO3M is more preferred, and CH2=CHSO3M is even more preferred.

[0284] The amount of the fluorine-free compound (A5) used in polymerizing the fluorine-containing monomer may be 3 to 5,000 ppm by mass, preferably 1 to 1,000 ppm by mass, more preferably 3 ppm by mass or more, even more preferably 5 ppm by mass or more, particularly preferably 10 ppm by mass or more, and most preferably 15 ppm by mass or more, and is more preferably 800 ppm by mass or less, even more preferably 500 ppm by mass or less, particularly preferably 250 ppm by mass or less, and most preferably 150 ppm by mass or less. By using the amount of the fluorine-free compound (A5) in polymerizing the fluorine-containing monomer within the above range, a larger amount of fluorine-containing elastomer particles can be generated, and adhesion of the fluorine-containing elastomer to the polymerization vessel can be further suppressed.

[0285] The compound (A1) having a triple bond and a hydrophilic group, the fluorine-containing compound (A2) represented by the general formula (A2), the fluorine-free compound (A3) represented by the general formula (A3), the compound (A4) having an aromatic ring, a hydrophilic group, and an unsaturated double bond, and the fluorine-free compound (A5) represented by the general formula (A5) all have functional groups that can react in radical polymerization, and therefore, when used in the above polymerization, they are presumed to react with the fluorine-containing monomer at the initial stage of the polymerization reaction, forming highly stable particles that have hydrophilic groups derived from these compounds. Therefore, it is thought that when polymerization is carried out in the presence of these compounds, the number of fluorine-containing elastomer particles generated during polymerization increases.

[0286] (Polymer (I)) The polymer (I) used in the production method of the present disclosure is a polymer containing polymerized units (I) based on the monomer (I). The monomer (I) is represented by the following general formula (I). CX 1 X 3 =CX 2 R(-CZ 1 Z 2 -A 0 ) m (I) (In the formula, X 1 and X 3 are each independently F, Cl, H, or CF; X 2 is H, F, an alkyl group or a fluorine-containing alkyl group; A 0 is an anionic group; R is a linking group; Z 1 and Z 2 are each independently H, F, an alkyl group or a fluorine-containing alkyl group; and m is an integer of 1 or greater.

[0287] In the present disclosure, the anionic group includes functional groups that provide anionic groups such as sulfate groups, carboxylate groups, acid groups such as -COOH, acid salt groups such as -COONH4, etc. Examples of anionic groups include sulfate groups, carboxylate groups, phosphate groups, phosphonate groups, sulfonate groups, or -C(CF3)2OM (wherein M is -H, a metal atom, -NR 7 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 7 is H or an organic group.

[0288] In the production method of the present disclosure, one or more types of monomers can be used as the monomer (I) represented by general formula (I).

[0289] R is a linking group. In the present disclosure, a "linking group" is an (m+1)-valent linking group, and when m is 1, it is a divalent linking group. The linking group may be a single bond and preferably contains at least one carbon atom, and the number of carbon atoms may be 2 or more, 4 or more, 8 or more, 10 or more, or 20 or more. There is no upper limit, but it may be, for example, 100 or less, or 50 or less.

[0290] The linking group may be linear or branched, cyclic or acyclic, saturated or unsaturated, substituted or unsubstituted, and may optionally contain one or more heteroatoms selected from the group consisting of sulfur, oxygen, and nitrogen, and may optionally contain one or more functional groups selected from the group consisting of ester, amide, sulfonamide, carbonyl, carbonate, urethane, urea, and carbamate. The linking group may not contain carbon atoms but may be a catenary heteroatom such as oxygen, sulfur, or nitrogen.

[0291] m is an integer of 1 or more, preferably 1 or 2, and more preferably 1. When m is an integer of 2 or more, Z 1 , Z 2 and A 0 may be the same or different. Next, a preferred structure when m is 1 in general formula (I) will be described.

[0292] R is preferably a catenary heteroatom such as oxygen, sulfur, or nitrogen, or a divalent organic group.

[0293] When R is a divalent organic group, the hydrogen atom bonded to the carbon atom may be replaced with a halogen atom other than fluorine, such as chlorine, and may or may not contain a double bond. R may be either linear or branched, and may be cyclic or acyclic. R may also contain a functional group (e.g., ester, ether, ketone (keto group), amine, halide, etc.).

[0294] R may also be a non-fluorinated divalent organic group, or a partially fluorinated or perfluorinated divalent organic group.

[0295] R may be, for example, a hydrocarbon group in which no fluorine atoms are bonded to the carbon atoms, a hydrocarbon group in which some of the hydrogen atoms bonded to the carbon atoms are substituted with fluorine atoms, or a hydrocarbon group in which all of the hydrogen atoms bonded to the carbon atoms are substituted with fluorine atoms, and these may contain an oxygen atom, a double bond, or a functional group.

[0296] R is preferably a hydrocarbon group having 1 to 100 carbon atoms which may contain an ether bond or a keto group, and in the hydrocarbon group, some or all of the hydrogen atoms bonded to the carbon atoms may be substituted with fluorine.

[0297] R is preferably -(CH2) a -, -(CF2) a -, -(CF2) a -O-, -O-(CF2) a -, -(CF2) a -O-(CF2) b -, -O(CF2) a -O-(CF2) b -, -(CF2) a -[O-(CF2) b ] c -, -O(CF2) a -[O-(CF2) b ] c -, -[(CF2) a -O] b -[(CF2) c -O] d -, -O[(CF2) a -O] b -, -O[(CF2) a -O] b -[(CF2) c -O] d -, -O-[CF2CF(CF3)O] a -(CF2) b -, -O-(CF2) a -O-[CF(CF3)CF2O]b -O-, -O-[CF2CF(CF3)O] a -(CF2) b -O-, -O-[CF2CF(CF3)O] a -(CF2) b -O-[CF(CF3)CF2O] c -O-, -[CF2CF(CF3)O] a -, -[CF(CF3)CF2O] a -, -(CF2) a -O-[CF(CF3)CF2O] a -, -(CF2) a -O-[CF(CF3)CF2O] a -(CF2) b -, -[CF2CF(CF3)] a -CO-(CF2) b - and at least one selected from the combinations thereof In the formula, a, b, c, and d are independently at least 1. a, b, c, and d may independently be 2 or more, 3 or more, 4 or more, 10 or more, or 20 or more. The upper limit of a, b, c, and d is, for example, 100. R is more preferably at least one selected from -O-CF2-, -O-CF2CF2-, -O-CF2CF2-O-, -O-CF2CF2CF2-, -O-CF2CF2CF2-O-, -O-CF2CF(CF3)-O-, -O-CF2CF2-O-CF(CF3)CF2-O-, -O-CF2CF(CF3)-O-CF2CF2-O-, and -O-CF2CF(CF3)-O-CF2-.

[0298] R is represented by the general formula (r1): -CF2-O-(CX 6 2) e -{O-CF(CF3)} f -(O) g - (r1) (In the formula, X 6 are each independently H, F or CF3, e is an integer of 0 to 3, f is an integer of 0 to 3, and g is 0 or 1), and a divalent group represented by the general formula (r2): -CF2-O-(CX 7 2) e -(O) g - (r2) (In the formula, X 7 are each independently H, F or CF3, e is an integer of 0 to 3, and g is 0 or 1), and a divalent group represented by the formula (I) is more preferred.

[0299] Specific examples suitable for R include -CF2-O-, -CF2-O-CF2-, -CF2-O-CH2-, -CF2-O-CH2CF2-, -O-CF2-, -O-CF2CF 2-, -O-CF2CF2CF2-, -O-CF2CF2CF2CF2-, -O-CF2CF(CF3)-O-CF2-, -O-CF2CF(CF3)-O-CF2CF2- , -CF2-O-CF2CF2-, -CF2-O-CF2CH2-, -CF2-O-CF2CF2CH2-, -CF2-O-CF(CF3)-, -CF2-O-CF(CF3 )CF2-, -CF2-O-CF(CF3)CF2-O-, -CF2-O-CF(CF3)CF2-O-CF2-, -CF2-O-CF(CF3)CH2-, and the like. Among these, R is preferably a perfluoroalkylene group which may contain an oxygen atom, specifically, -CF2-O-, -CF2-O-CF2-, -O-CF2-, -O-CF2CF2-, -O-CF2CF(CF3)-O-CF2-, -O-CF2CF(CF3)-O-CF2CF2-, -CF2-O-CF2CF2-, -CF2-O-CF(CF3)-, -CF2-O-CF(CF3)CF2-, or -CF2-O-CF(CF3)CF2-O- is preferred.

[0300] -R-CZ of general formula (I) 1 Z 2 - is a compound represented by the general formula (s1): -CF2-O-(CX 6 2) e -{O-CF(CF3)} f -(O) g -CZ 1 Z 2 - (s1) (In the formula, X 6are each independently H, F, or CF3, e is an integer of 0 to 3, f is an integer of 0 to 3, g is 0 or 1, and Z 1 and Z 2 are each independently H, F, an alkyl group or a fluorine-containing alkyl group), and in formula (s1), Z 1 and Z 2 More preferably, they are F or CF3, and even more preferably, one is F and the other is CF3.

[0301] In addition, in the general formula (I), -R-CZ 1 Z 2 - as the general formula (s2): -CF2-O-(CX 7 2) e -(O) g -CZ 1 Z 2 - (s2) (In the formula, X 7 are each independently H, F, or CF3, e is an integer of 0 to 3, g is 0 or 1, and Z 1 and Z 2 are each independently H, F, an alkyl group or a fluorine-containing alkyl group), and in formula (s2), Z 1 and Z 2 More preferably, they are F or CF3, and even more preferably, one is F and the other is CF3.

[0302] -R-CZ of general formula (I) 1 Z 2- as -CF2-O-CF2-, -CF2-O-CF(CF3)-, -CF2-OC(CF3)2-, -CF2-O-CF2-CF2-, -CF2-O-CF2-CF(CF3)-, -CF2-O-CF 2-C(CF3)2-, -CF2-O-CF2CF2-CF2-, -CF2-O-CF2CF2-CF(CF3)-, -CF2-O-CF2CF2-C(CF3)2-, -CF2-O-CF(CF3)-CF2 -, -CF2-O-CF(CF3)-CF(CF3)-, -CF2-O-CF(CF3)-C(CF3)2-, -CF2-O-CF(CF3)-CF2-, -CF2-O-CF(CF3)-CF(CF3)-, -CF2-O-CF(CF3)-C(CF3)2-, -CF2-O-CF(CF3)CF2-CF2-, -CF2-O-CF(CF3)CF2-CF(CF3)-, -CF2-O-CF(CF3)CF2-C( CF3)2-, -CF2-O-CF(CF3)CF2-O-CF2-, -CF2-O-CF(CF3)CF2-O-CF(CF3)-, or -CF2-O-CF(CF3)CF2-OC(CF3)2- is preferred. Exactly, -O-CF2CF2-, -O-CF2CF2CF2-, -O-CF2CF2CF2CF2-, -O-CF2CF(CF3)-O-CF2-, -O-CF2CF(CF3)-O-CF2CF2-, -CF 2-O-CF(CF3)-, -CF2-O-CF2-CF(CF3)-, -CF2-O-CF2CF2-CF(CF3)-, -CF2-O-CF(CF3)-CF(CF3)-, -CF2-O-CF(CF3)CF2-CF(CF3)-, or -CF2-O-CF(CF3)CF2-O-CF(CF3)- are more preferred, with -O-CF2CF2- and -O-CF2CF(CF3)-O-CF2CF2- being even more preferred.

[0303] It is also preferred that the polymer (I) is highly fluorinated. For example, it may contain anionic groups (A) such as phosphate moieties (e.g., CH2OP(O)(OM)2) and sulfate moieties (e.g., CH2OS(O)2OM). 0 ), it is preferred that 80% or more, 90% or more, 95% or more, or 100% of the C—H bonds in the polymer (I) are substituted with C—F bonds.

[0304] The monomer (I) and the polymer (I) contain an anionic group (A 0 ) except for the C—F bond, it is also preferable that the compound has no C—H bond. 1 , X 2 , and X 3 are all F, and R is a perfluoroalkylene group having one or more carbon atoms, and the perfluoroalkylene group may be either linear or branched, may be cyclic or acyclic, and may contain at least one catenary heteroatom. The number of carbon atoms in the perfluoroalkylene group may be 2 to 20, or may be 4 to 18.

[0305] The monomer (I) and the polymer (I) may be partially fluorinated. That is, the monomer (I) and the polymer (I) may contain an anionic group (A 0 ), it is also preferred that the alkyl group has at least one hydrogen atom bonded to a carbon atom and at least one fluorine atom bonded to a carbon atom.

[0306] Anionic group (A 0 ) can be —SO2M, —SO3M, —OSO3M, —COOM, —SONR′CH2COOM, —CH2OP(O)(OM)2, [—CH2O]2P(O)(OM), —CH2CH2OP(O)(OM)2, [—CH2CH2O]2P(O)(OM), —CH2CH2OSO3M, —P(O)(OM)2, —SON2NR′CH2CH2OP(O)(OM)2, [—SON2NR′CH2CH2O]2P(O)(OM), —CH2OSO3M, —SON2NR′CH2CH2OSO3M, or —C(CF3)2OM. Of these, -SO3M, -OSO3M, -COOM, -P(O)(OM)2 or -C(CF3)2OM are preferred, -COOM, -SO3M, -OSO3M, -P(O)(OM)2 or -C(CF3)2OM are more preferred, -SO3M, -COOM or -P(O)(OM)2 are even more preferred, -SO3M or -COOM is particularly preferred, and -SO3M is most preferred.

[0307] M is H, metal atom, NR 7 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 7 is H or an organic group.

[0308] Examples of the metal atom include alkali metals (Group 1) and alkaline earth metals (Group 2), and Na, K or Li is preferred.

[0309] M is -H, a metal atom, or NR 7 4 is preferred, and -H, an alkali metal (Group 1), an alkaline earth metal (Group 2) or NR 7 4 is more preferred, -H, -Na, -K, -Li or NH4 is even more preferred, -H, -Na, -K or NH4 is even more preferred, -H, -Na or NH4 is especially preferred, and -H or -NH4 is most preferred.

[0310] In the polymer (I), each polymer unit (I) may have a different anionic group or may have the same anionic group.

[0311] The monomer (I) is also preferably a monomer represented by the general formula (Ia). The polymer (I) is also preferably a polymer containing polymerized units (Ia) based on a monomer represented by general formula (Ia). CF2=CF-O-Rf 0 -A 0 (Ia) (In the formula, A 0 is an anionic group, and Rf 0 is a perfluorinated divalent linking group that may be linear or branched, cyclic or acyclic in structure, saturated or unsaturated, substituted or unsubstituted, and optionally contains one or more heteroatoms selected from the group consisting of sulfur, oxygen, and nitrogen.

[0312] The monomer (I) is also preferably a monomer represented by the general formula (Ib). The polymer (I) is also preferably a polymer containing polymerized units (Ib) based on a monomer represented by general formula (Ib). CH2=CH-O-Rf 0 -A 0 (Ib) (In the formula, A 0 is an anionic group, and Rf 0 is a perfluorinated divalent linking group defined by formula Ia.

[0313] In general formula (I), A 0 is a sulfate group. 0 is, for example, -CH2OSO3M, -CH2CH2OSO3M, or -SO2NR'CH2CH2OSO3M, where R' is H or an alkyl group having 1 to 4 carbon atoms, and M is the same as above.

[0314] A 0 is a sulfate group, examples of the monomer represented by general formula (I) include CF2=CF(OCF2CF2CH2OSO3M), CF2=CF(O(CF2)4CH2OSO3M), CF2=CF(OCF2CF(CF3)CH2OSO3M), CF2=CF(OCF2CF(CF3)OCF2CF2CH2OSO3M), CH2=CH((CF2)4CH2OSO3M), CF2=CF(OCF2CF2SON(CH3)CH2CH2OSO3M), CH2=CH(CF2CF2CH2OSO3M), CF2=CF(OCF2CF2CF2CF2SON(CH3)CH2CH2OSO3M), CH2=CH(CF2CF2CH2OSO3M), etc. In the above formulas, M is the same as above.

[0315] In general formula (I), A 0 In one preferred embodiment, A is a sulfonate group. 0 An example is -SO3M, where M is the same as above.

[0316] A 0is a sulfonate group, examples of the monomer represented by general formula (I) include CF2=CF(OCF2CF2SO3M), CF2=CF(O(CF2)3SO3M), CF2=CF(O(CF2)4SO3M), CF2=CF(OCF2CF(CF3)SO3M), CF2=CF(OCF2CF(CF3)OCF2CF2SO3M), CH2=CH(CF2CF2SO3M), CF2=CF(OCF2CF(CF3)OCF2CF2CF2CF2SO3M), CH2=CH((CF2)4SO3M), CH2=CH((CF2)3SO3M), etc. In the above formulas, M is the same as above.

[0317] In general formula (I), A 0 A is preferably a carboxylate group. 0 Examples of the compound include COOM or SO2NR'CH2COOM, where R' is H or an alkyl group having 1 to 4 carbon atoms, and M is the same as above. 0 is a carboxylate group, examples of the monomer represented by general formula (I) include CF2=CF(OCF2CF2COOM), CF2=CF(O(CF2)3COOM), CF2=CF(O(CF2)5COOM), CF2=CF(OCF2CF(CF3)COOM), CF2=CF(OCF2CF(CF3)O(CF2) n COOM) (n is greater than 1), CH2=CH(CF2CF2COOM), CH2=CH((CF2)4COOM), CH2=CH((CF2)3COOM), CF2=CF(OCF2CF2SO2NR'CH2COOM), CF2=CF(O(CF2)4SO2NR'CH2COOM), CF2=CF(OCF2CF(CF3)SO2NR'CH2COOM), CF2=CF(OCF2CF(CF3)OCF2CF2SO2NR'CH2COOM), CH2=CH(CF2CF2SO2NR'CH2COOM), CF2=CF(OCF2CF(CF3)OCF2CF2CF2CF2SO2NR'CH2COOM), CH2=CH((CF2)4SO2NR'CH2COOM), CH2=CH((CF2)3SO2NR'CH2COOM). In the above formula, R' is H or an alkyl group having 1 to 4 carbon atoms, and M is the same as above.

[0318] In general formula (I), A 0 In one preferred embodiment, A is a phosphate group. 0 Examples of such a group include -CH2OP(O)(OM)2, [-CHO]2P(O)(OM), -CH2CH2OP(O)(OM)2, [-CH2CH2O]2P(O)(OM), [-SON2NR'CH2CH2O]2P(O)(OM) or SO2NR'CH2CH2OP(O)(OM)2, where R' is an alkyl group having 1 to 4 carbon atoms and M is as defined above.

[0319] A 0 is a phosphate, examples of the monomer represented by general formula (I) include CF2=CF(OCF2CF2CH2OP(O)(OM)2), CF2=CF(O(CF2)4CH2OP(O)(OM)2), CF2=CF(OCF2CF(CF3)CH2OP(O)(OM)2), CF2=CF(OCF2CF(CF3)OCF2CF2CH2OP(O)(OM)2), CF2=CF(O Examples include CF2CF2SO2N(CH3)CH2CH2OP(O)(OM)2), CF2=CF(OCF2CF2CF2CF2SO2N(CH3)CH2CH2OP(O)(OM)2), CH2=CH(CF2CF2CH2OP(O)(OM)2), CH2=CH((CF2)4CH2OP(O)(OM)2), CH2=CH((CF2)3CH2OP(O)(OM)2), etc. In the above formula, M is the same as above.

[0320] In general formula (I), A 0 In one preferred embodiment, A is a phosphonate group. 0is a phosphonate group, examples of the monomer represented by general formula (I) include CF2=CF(OCF2CF2P(O)(OM)2), CF2=CF(O(CF2)4P(O)(OM)2), CF2=CF(OCF2CF(CF3)P(O)(OM)2), CF2=CF(OCF2CF(CF3)OCF2CF2P(O)(OM)2), CH2=CH(CF2CF2P(O)(OM)2), CH2=CH((CF2)4P(O)(OM)2), CH2=CH((CF2)3P(O)(OM)2), where M is the same as above.

[0321] The monomer (I) is preferably a monomer (1) represented by the general formula (1). The polymer (I) is preferably a polymer (1) containing polymerized units (1) based on a monomer represented by general formula (1). CX2=CY(-CZ2-O-Rf-A) (1) (In the formula, X's may be the same or different and each represent -H or F; Y's may be -H, -F, an alkyl group, or a fluorine-containing alkyl group; and Z's may be the same or different and each represent -H, -F, an alkyl group, or a fluoroalkyl group. Rf's each represent a fluorine-containing alkylene group having 1 to 40 carbon atoms, or a fluorine-containing alkylene group having 2 to 100 carbon atoms and an ether bond. A's each represent -COOM, -SO3M, -OSO3M, or -C(CF3)2OM (M's each represent -H, a metal atom, or -NR 7 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 7 is H or an organic group.) However, at least one of X, Y, and Z contains a fluorine atom.)

[0322] In the production method of the present disclosure, the monomer (1) represented by general formula (1) may be copolymerized with other monomers. The polymer (1) may be a homopolymer of the fluoroallyl ether compound represented by the general formula (1), or may be a copolymer with other monomers.

[0323] The fluorine-containing alkylene group having 2 to 100 carbon atoms and an ether bond is an alkylene group that does not contain a structure in which an oxygen atom is at the terminal and that contains an ether bond between carbon atoms.

[0324] In general formula (1), X is -H or F. Both Xs may be -F, or at least one X may be -H. For example, one X may be -F and the other may be -H, or both Xs may be -H.

[0325] In general formula (1), Y is -H, -F, an alkyl group, or a fluorine-containing alkyl group. The alkyl group is an alkyl group that does not contain a fluorine atom, and may have one or more carbon atoms. The alkyl group preferably has six or fewer carbon atoms, more preferably four or fewer carbon atoms, and even more preferably three or fewer carbon atoms. The fluorine-containing alkyl group is an alkyl group that contains at least one fluorine atom, and may have one or more carbon atoms. The fluorine-containing alkyl group preferably has six or fewer carbon atoms, more preferably four or fewer carbon atoms, and even more preferably three or fewer carbon atoms. Y is preferably -H, -F, or CF3, and more preferably -F.

[0326] In general formula (1), Z's may be the same or different and represent -H, -F, an alkyl group, or a fluoroalkyl group. The alkyl group is an alkyl group that does not contain a fluorine atom, and may have one or more carbon atoms. The alkyl group preferably has six or fewer carbon atoms, more preferably four or fewer carbon atoms, and even more preferably three or fewer carbon atoms. The fluorine-containing alkyl group is an alkyl group that contains at least one fluorine atom, and may have one or more carbon atoms. The fluorine-containing alkyl group preferably has six or fewer carbon atoms, more preferably four or fewer carbon atoms, and even more preferably three or fewer carbon atoms. Z's are preferably -H, -F, or CF3, and more preferably -F.

[0327] In general formula (1), at least one of X, Y, and Z contains a fluorine atom. For example, X may be —H, and Y and Z may be —F.

[0328] In the general formula (1), Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms or a fluorine-containing alkylene group having 2 to 100 carbon atoms and an ether bond.

[0329] The number of carbon atoms in the fluorine-containing alkylene group is preferably 2 or more. The number of carbon atoms in the fluorine-containing alkylene group is preferably 30 or less, more preferably 20 or less, even more preferably 10 or less, particularly preferably 6 or less, and most preferably 3 or less. Examples of the fluorine-containing alkylene group include -CF2-, -CH2CF2-, -CF2CF2-, -CF2CH2-, -CF2CF2CF2-, -CF2CF2CH2-, -CF(CF3)-, -CF(CF3)CF2-, and -CF(CF3)CH2-. The fluorine-containing alkylene group is preferably a perfluoroalkylene group.

[0330] The number of carbon atoms in the fluorine-containing alkylene group having an ether bond is preferably 3 or more. The number of carbon atoms in the fluorine-containing alkylene group having an ether bond is preferably 60 or less, more preferably 30 or less, even more preferably 12 or less, particularly preferably 9 or less, and most preferably 6 or less. The fluorine-containing alkylene group having an ether bond is, for example, a group represented by the general formula: [ka] (In the formula, Z 1 is F or CF3;Z 2 and Z 3 are H or F;Z respectively 4 is also preferably a divalent group represented by the formula: H, F, or CF3; p1+q1+r1 is an integer of 1 to 10; s1 is 0 or 1; and t1 is an integer of 0 to 5).

[0331] Specific examples of the fluorine-containing alkylene group having an ether bond include -CFCF(CF)OCF-, -CF(CF)CF-O-CF(CF)-, -(CF(CF)CF-O) n -CF(CF3)- (wherein n is an integer of 1 to 10), -CF(CF3)CF2-O-CF(CF3)CH2-, -(CF(CF3)CF2-O) nExamples include -CF(CF3)CH2- (wherein n is an integer of 1 to 10), -CH2CF2CF2O-CH2CF2CH2-, -CF2CF2CF2O-CF2CF2-, -CF2CF2CF2O-CF2CF2CH2-, -CF2CF2O-CF2-, -CF2CF2O-CF2CH2-, etc. The fluorine-containing alkylene group having an ether bond is preferably a perfluoroalkylene group.

[0332] In the general formula (1), A is -COOM, -SO3M, -OSO3M, or -C(CF3)2OM (M is H, a metal atom, or NR 7 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 7 is H or an organic group).

[0333] R 7 As for H or C 1-10 is preferably an organic group represented by the formula: 1-4 The organic group is more preferably H or C 1-4 More preferred are alkyl groups of the formula:

[0334] Examples of the metal atom include alkali metals (Group 1) and alkaline earth metals (Group 2), and Na, K or Li is preferred.

[0335] M is H, a metal atom, or NR 7 4 is preferred, H, an alkali metal (Group 1), an alkaline earth metal (Group 2) or NR 7 4 is more preferred, H, Na, K, Li or NH4 is even more preferred, H, Na, K or NH4 is even more preferred, H, Na or NH4 is especially preferred, and H or NH4 is most preferred.

[0336] A is preferably —COOM or —SO3M, and more preferably —COOM.

[0337] Examples of the monomer represented by general formula (1) include a monomer represented by general formula (1a): CX2=CFCF2-O-(CF(CF3)CF2O) n5 -CF(CF3)-A (1a) (wherein each X is the same and represents F or H, n5 represents 0 or an integer of 1 to 10, and A is as defined above) is a preferred example of a fluoroallyl ether compound.

[0338] In general formula (1a), n5 is preferably 0 or an integer of 1 to 5, more preferably 0, 1 or 2, and even more preferably 0 or 1, in that particles with a small primary particle size can be obtained.

[0339] In the production method of the present disclosure, the monomer represented by general formula (1a) may be copolymerized with other monomers. The polymer (1) may be a homopolymer of the fluoroallyl ether compound represented by the general formula (1a), or may be a copolymer with other monomers.

[0340] The monomer (1) is preferably a monomer represented by the general formula (1A). The polymerized unit (1) is preferably a polymerized unit (1A) based on a monomer represented by general formula (1A). CH2=CF(-CF2-O-Rf-A) (1A) (wherein Rf and A are the same as above.)

[0341] In the production method of the present disclosure, the monomer represented by general formula (1A) may be copolymerized with other monomers. The polymer (1) may be a homopolymer of the monomer represented by the general formula (1A) or a copolymer with other monomers.

[0342] Specific examples of the monomer represented by formula (1A) include the monomer represented by the general formula:

[0343] [ka]

[0344] (In the formula, Z 1 is F or CF3;Z 2 and Z 3 are H or F;Z respectively 4 is H, F, or CF3; p1+q1+r1 are integers from 0 to 10; s1 is 0 or 1; t1 is an integer from 0 to 5, except for Z 3 and Z 4 are both H, then p1+q1+r1+s1 is not 0; A is the same as defined above). More specifically,

[0345] [ka]

[0346] Among them,

[0347] [ka]

[0348] It is preferable that:

[0349] As the monomer represented by general formula (1A), it is preferable that A in formula (1A) is -COOM, and in particular, at least one selected from the group consisting of CH2=CFCF2OCF(CF3)COOM and CH2=CFCF2OCF(CF3)CF2OCF(CF3)COOM (wherein M is as defined above) is preferred, with CH2=CFCF2OCF(CF3)COOM being more preferred.

[0350] Further, examples of the monomer represented by the general formula (1) include the monomer represented by the following formula: CF2=CFCF2-O-Rf-A (wherein Rf and A are the same as above)

[0351] More specifically, [ka] etc.

[0352] The monomer (I) is also preferably a monomer (2) represented by the general formula (2). The polymer (I) is also preferably a polymer (2) containing polymerized units (2) based on a monomer represented by general formula (2). CX2=CY(-O-Rf-A) (2) (In the formula, X's are the same or different and represent -H or F; Y represents -H, -F, an alkyl group or a fluorine-containing alkyl group; Rf represents a fluorine-containing alkylene group having 1 to 40 carbon atoms or a fluorine-containing alkylene group having 2 to 100 carbon atoms and having an ether bond or a keto group; and A is the same as defined above.)

[0353] In the production method of the present disclosure, the monomer (2) represented by general formula (2) may be copolymerized with other monomers. The polymer (2) may be a homopolymer of the monomer represented by the general formula (2) or a copolymer with other monomers.

[0354] In general formula (2), X is -H or F. Both Xs may be -F, or at least one X may be -H. For example, one X may be -F and the other may be -H, or both Xs may be -H.

[0355] In general formula (2), Y is -H, -F, an alkyl group, or a fluorine-containing alkyl group. The alkyl group is an alkyl group that does not contain a fluorine atom, and may have one or more carbon atoms. The alkyl group preferably has six or fewer carbon atoms, more preferably four or fewer carbon atoms, and even more preferably three or fewer carbon atoms. The fluorine-containing alkyl group is an alkyl group that contains at least one fluorine atom, and may have one or more carbon atoms. The fluorine-containing alkyl group preferably has six or fewer carbon atoms, more preferably four or fewer carbon atoms, and even more preferably three or fewer carbon atoms. Y is preferably -H, -F, or CF3, and more preferably -F.

[0356] In general formula (2), it is preferable that at least one of X and Y contains a fluorine atom. For example, X may be —H, and Y and Z may be —F.

[0357] In general formula (2), Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms, a fluorine-containing alkylene group having an ether bond having 2 to 100 carbon atoms, or a fluorine-containing alkylene group having a keto group having 2 to 100 carbon atoms. The fluorine-containing alkylene group having an ether bond having 2 to 100 carbon atoms is an alkylene group that does not contain a structure in which an oxygen atom is at the terminal and that contains an ether bond between carbon atoms.

[0358] The number of carbon atoms in the fluorine-containing alkylene group of Rf is preferably 2 or more. Also, it is preferably 30 or less, more preferably 20 or less, even more preferably 10 or less, and particularly preferably 5 or less. Examples of the fluorine-containing alkylene group include -CF2-, -CH2CF2-, -CF2CF2-, -CF2CH2-, -CF2CF2CH2-, -CF(CF3)-, -CF(CF3)CF2-, -CF(CF3)CH2-, -CF2CF2CF2-, -CF2CF2CF2CF2-, and the like. The fluorine-containing alkylene group is preferably a perfluoroalkylene group, and more preferably an unbranched linear perfluoroalkylene group.

[0359] The number of carbon atoms in the fluorine-containing alkylene group having an ether bond is preferably 3 or more. The number of carbon atoms in the fluorine-containing alkylene group having an ether bond is preferably 60 or less, more preferably 30 or less, even more preferably 12 or less, and particularly preferably 5 or less. The fluorine-containing alkylene group having an ether bond is, for example, a group represented by the general formula: [ka] (In the formula, Z 1 is F or CF3;Z 2 and Z 3 are H or F;Z respectively 4is also preferably a divalent group represented by the formula: H, F, or CF3; p1+q1+r1 is an integer of 1 to 10; s1 is 0 or 1; and t1 is an integer of 0 to 5).

[0360] Specific examples of the fluorine-containing alkylene group having an ether bond include -CF2CF(CF3)OCF2-, -CF2CF(CF3)OCF2CF2-, -CF2CF(CF3)OCF2CF2CF2-, -CF(CF3)CF2-O-CF(CF3)-, -(CF(CF3)CF2-O) n -CF(CF3)- (wherein n is an integer of 1 to 10), -CF(CF3)CF2-O-CF(CF3)CH2-, -(CF(CF3)CF2-O) n Examples include -CF(CF3)CH2- (wherein n is an integer of 1 to 10), -CH2CF2CF2O-CH2CF2CH2-, -CF2CF2CF2O-CF2-, -CF2CF2CF2O-CF2CF2-, -CF2CF2CF2O-CF2CF2-, -CF2CF2CF2O-CF2CF2CH2-, -CF2CF2O-CF2-, -CF2CF2O-CF2CH2-, etc. The fluorine-containing alkylene group having an ether bond is preferably a perfluoroalkylene group.

[0361] The carbon number of the fluorine-containing alkylene group having a keto group is preferably 3 or more. The carbon number of the fluorine-containing alkylene group having a keto group is preferably 60 or less, more preferably 30 or less, even more preferably 12 or less, and particularly preferably 5 or less.

[0362] Specific examples of the fluorine-containing alkylene group having a keto group include -CF2CF(CF3)CO-CF2-, -CF2CF(CF3)CO-CF2CF2-, -CF2CF(CF3)CO-CF2CF2CF2-, -CF2CF(CF3)CO-CF2CF2CF2-, etc. The fluorine-containing alkylene group having a keto group is preferably a perfluoroalkylene group.

[0363] Water may be added to the keto group in the fluorine-containing alkylene group. Therefore, the monomer (2) may be a hydrate. Examples of the fluorine-containing alkylene group in which water is added to the keto group include -CFCF(CF)C(OH)-CF-, -CFCF(CF)C(OH)-CFCF-, -CFCF(CF)C(OH)-CFCFCF-, and -CFCF(CF)C(OH)-CFCFCFCF-.

[0364] In the general formula (2), A is -COOM, -SO3M, -OSO3M, or -C(CF3)2OM (M is H, a metal atom, or NR 7 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 7 is H or an organic group).

[0365] R 7 As for H or C 1-10 is preferably an organic group represented by the formula: 1-4 The organic group is more preferably H or C 1-4 More preferred are alkyl groups of the formula:

[0366] Examples of the metal atom include alkali metals (Group 1) and alkaline earth metals (Group 2), and Na, K or Li is preferred.

[0367] M is H, a metal atom, or NR 7 4 is preferred, H, an alkali metal (Group 1), an alkaline earth metal (Group 2) or NR 7 4 is more preferred, H, Na, K, Li or NH4 is even more preferred, H, Na, K or NH4 is even more preferred, and H, Na or NH4 is especially preferred.

[0368] A is preferably -COOM or -SO3M, and more preferably -SO3M.

[0369] The monomer represented by general formula (2) is preferably at least one selected from the group consisting of monomers represented by general formulas (2a), (2b), (2c), (2d) and (2e). CF2=CF-O-(CF2) n1 -A (2a) (wherein n1 represents an integer of 1 to 10, and A is the same as defined above.) CF2=CF-O-(CF2C(CF3)F) n2 -A (2b) (wherein n2 represents an integer of 1 to 5, and A is as defined above.) CF2=CF-O-(CFX 1 ) n3 -A (2c) (In the formula, X 1 represents F or CF3, n3 represents an integer of 1 to 10, and A is as defined above. CF2=CF-O-(CF2CFX 1 O) n4 -(CF2) n6 -A (2d) (wherein n4 represents an integer of 1 to 10, n6 represents an integer of 1 to 3, and A and X 1 is the same as the definition above.) CF2=CF-O-(CF2CF2CFX 1 O) n5 -CF2CF2CF2-A (2e) (wherein n5 represents an integer of 0 to 10, and A and X 1 is the same as the definition above.)

[0370] In the general formula (2a), n1 is preferably an integer of 5 or less, and more preferably an integer of 2 or less.

[0371] Examples of the monomer represented by general formula (2a) include CF2=CF-O-CF2COOM, CF2=CF(OCF2CF2COOM), CF2=CF(O(CF2)3COOM), CF2=CF(OCF2CF2SO3M), CF2=CFO(CF2SO3M), and CF2=CFO(CF2CF2CF2SO3M) (wherein M is as defined above).

[0372] In general formula (2b), n2 is preferably an integer of 3 or less, from the viewpoint of the dispersion stability of the resulting composition.

[0373] In general formula (2c), n3 is preferably an integer of 5 or less from the viewpoint of water solubility, A is preferably -COOM, and M is preferably H or NH4.

[0374] In general formula (2d), X 1 is preferably -CF3 from the viewpoint of dispersion stability of the composition, n4 is preferably an integer of 5 or less from the viewpoint of water solubility, A is preferably -COOM, and M is preferably H or NH4.

[0375] Examples of the monomer represented by general formula (2d) include CF2=CFOCF2CF(CF3)OCF2CF2COOM, CF2=CFOCF2CF(CF3)OCF2COOM, CF2=CFOCF2CF(CF3)OCF2CF2CF2COOM, CF2=CFOCF2CF(CF3)OCF2CF2CF2COOM, CF2=CFOCF2CF(CF3)OCF2SO3M, CF2=CFOCF2CF(CF3)OCF2CF2SO3M, CF2=CFOCF2CF(CF3)OCF2CF2CF2SO3M (wherein M represents H, NH4 or an alkali metal).

[0376] In general formula (2e), n5 is preferably an integer of 5 or less from the viewpoint of water solubility, A is preferably -COOM, and M is preferably H or NH4.

[0377] Examples of the monomer represented by general formula (2e) include CF2=CFOCF2CF2CF2COOM (wherein M represents H, NH4 or an alkali metal).

[0378] The monomer (I) is also preferably a monomer (3) represented by the general formula (3). The polymer (I) is also preferably a polymer (3) containing polymerized units (3) based on a monomer represented by general formula (3). CX2=CY(-Rf-A) (3) (In the formula, X's are the same or different and represent -H or F; Y represents -H, -F, an alkyl group or a fluorine-containing alkyl group; Rf represents a fluorine-containing alkylene group having 1 to 40 carbon atoms or a fluorine-containing alkylene group having an ether bond having 2 to 100 carbon atoms; and A is the same as defined above.)

[0379] In the production method of the present disclosure, the monomer (3) represented by general formula (3) may be copolymerized with other monomers. The polymer (3) may be a homopolymer of the monomer represented by the general formula (3) or a copolymer with other monomers.

[0380] The fluorine-containing alkylene group having 2 to 100 carbon atoms and an ether bond is an alkylene group that does not contain a structure in which an oxygen atom is at the terminal and that contains an ether bond between carbon atoms.

[0381] In general formula (3), Rf is preferably a fluorine-containing alkylene group having a carbon number of 1 to 40. In general formula (3), at least one of X and Y preferably contains a fluorine atom.

[0382] The monomer represented by general formula (3) is represented by general formula (3a): CF2=CF-(CF2) n1 -A (3a) (wherein n1 represents an integer of 1 to 10, and A is as defined above), and a monomer represented by general formula (3b): CF2=CF-(CF2C(CF3)F) n2 -A (3b) (wherein n2 represents an integer of 1 to 5, and A is as defined above), is preferred.

[0383] In the general formula (3a) and the general formula (3b), A is preferably —SO3M or COOM, and M is H, a metal atom, NR 7 4. It is preferably an imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent. 7 represents H or an organic group.

[0384] In general formula (3a), n1 is preferably an integer of 5 or less, more preferably an integer of 2 or less. A is preferably -COOM, and M is preferably H or NH4.

[0385] An example of the monomer represented by general formula (3a) is CF2=CFCF2COOM (wherein M is as defined above).

[0386] In general formula (3b), n2 is preferably an integer of 3 or less from the viewpoint of dispersion stability of the resulting composition, A is preferably -COOM, and M is preferably H or NH4.

[0387] Next, a preferred configuration when m in general formula (I) is an integer of 2 or more will be described.

[0388] It is also preferable that the monomer (I) is at least one selected from the group consisting of monomers represented by general formula (4a) and general formula (4b). It is also preferable that the polymer (I) is a polymer (4) containing polymerization units (4) based on at least one monomer selected from the group consisting of monomers represented by general formula (4a) and general formula (4b). CF2=CF-CF2-OQ F1 -CF(-Q F2 -CZ 1 Z 2 -A)2(4a) (In the formula, Z 1 , Z 2 and A are the same as above, Q F1 and Q F2are the same or different and are a single bond, a fluorine-containing alkylene group which may contain an ether bond between carbon atoms, or a fluorine-containing oxyalkylene group which may contain an ether bond between carbon atoms. CF2=CF-OQ F1 -CF(-Q F2 -CZ 1 Z 2 -A)2(4b) (In the formula, Z 1 , Z 2 , A, Q F1 and Q F2 is the same as above)

[0389] The monomers represented by general formula (4a) and general formula (4b) include: [ka] etc.

[0390] The monomer (I) is preferably at least one selected from the group consisting of the monomer (1), the monomer (2) and the monomer (3), and more preferably the monomer (2). The polymer (I) is preferably at least one selected from the group consisting of polymer (1), polymer (2) and polymer (3), and more preferably polymer (2).

[0391] In the production method of the present disclosure, the monomer (I) may be copolymerized with other monomers. The polymer (I) may be a homopolymer consisting of only the polymerized unit (I), or a copolymer containing the polymerized unit (I) and a polymerized unit based on another monomer copolymerizable with the monomer (I) represented by the general formula (I). From the viewpoint of solubility in an aqueous medium, a homopolymer consisting of only the polymerized unit (I) is preferred. The polymerized units (I) may be the same or different in each occurrence, and the polymer (I) may contain polymerized units (I) based on two or more different monomers represented by the general formula (I). By using, as the polymer (I), a copolymer containing polymerization units (I) and polymerization units based on other monomers copolymerizable with the monomer (I) represented by the general formula (I), the adhesion of the fluorine-containing elastomer to the polymerization vessel can be further reduced.

[0392] The other monomer is preferably a monomer represented by the general formula CFR=CR2 (wherein R is independently H, F, or a perfluoroalkyl group having 1 to 4 carbon atoms). Also, the other monomer is preferably a fluorine-containing ethylenic monomer having 2 or 3 carbon atoms. Examples of the other monomer include CF2=CF2, CF2=CFCl, CH2=CF2, CFH=CH2, CFH=CF2, CF2=CFCF3, CH2=CFCF3, CH2=CHCF3, CHF=CHCF3 (E-isomer), CHF=CHCF3 (Z-isomer), etc. Among these, the other monomer is preferably at least one selected from the group consisting of tetrafluoroethylene (CF2=CF2), chlorotrifluoroethylene (CF2=CFCl), and vinylidene fluoride (CH2=CF2), in terms of good copolymerizability, more preferably at least one selected from the group consisting of tetrafluoroethylene and vinylidene fluoride, and even more preferably vinylidene fluoride. Therefore, the polymerized units based on the other monomer are preferably at least one selected from the group consisting of polymerized units based on tetrafluoroethylene and polymerized units based on vinylidene fluoride, and even more preferably polymerized units based on vinylidene fluoride. The polymerized units based on the other monomer may be the same or different in each occurrence, and the polymer (I) may contain polymerized units based on two or more different other monomers.

[0393] The other monomers also include those represented by the general formula (n1-2):

[0394] [ka]

[0395] (In the formula, X 1 , X 2are the same or different H or F;X 3 is H, F, Cl, CH3 or CF3; X 4 , X 5 are the same or different and are H or F; a and c are the same or different and are 0 or 1. Rf 3 is a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having 2 to 100 carbon atoms and having an ether bond).

[0396] Specifically, CH2=CFCF2-O-Rf 3 , CF2=CF-O-Rf 3 , CF2=CFCF2-O-Rf 3 , CF2=CF-Rf 3 , CH2=CH-Rf 3 , CH2=CH-O-Rf 3 (In the formula, Rf 3 is the same as the above formula (n1-2)).

[0397] Examples of the other monomers include those of formula (n2-1):

[0398] [ka]

[0399] (In the formula, X 9 is H, F or CH3; Rf 4 Also included are fluorine-containing acrylate monomers represented by Rf (a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having 2 to 100 carbon atoms and an ether bond). 4 The base is

[0400] [ka]

[0401] (wherein d3 is an integer of 1 to 4; e3 is an integer of 1 to 10).

[0402] Examples of the other monomers include those of formula (n2-2): CH2=CHO-Rf 5 (n2-2) (In the formula, Rf 5 is a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having 2 to 100 carbon atoms and having an ether bond).

[0403] Specific examples of the monomer of general formula (n2-2) include:

[0404] [ka]

[0405] (wherein e6 is an integer of 1 to 10) are preferred.

[0406] More specifically,

[0407] [ka]

[0408] Examples include:

[0409] Others include those of general formula (n2-3): CH2=CHCH2O-Rf 6 (n2-3) (In the formula, Rf 6 is a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having 2 to 100 carbon atoms and having an ether bond), a fluorine-containing allyl ether represented by the general formula (n2-4): CH2=CH-Rf 7 (n2-4) (In the formula, Rf 7 is a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having 2 to 100 carbon atoms and having an ether bond), and the like.

[0410] Specific examples of the monomers represented by general formulas (n2-3) and (n2-4) include:

[0411] [ka]

[0412] Examples of such monomers include:

[0413] In the polymer (I), the content of the polymerized units (I) relative to all polymerized units is, in order of decreasing preference, 1.0 mol% or more, 3.0 mol% or more, 5.0 mol% or more, 10 mol% or more, 20 mol% or more, 30 mol% or more, 40 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, and 90 mol% or more. The content of the polymerized units (I) is particularly preferably substantially 100 mol%, and the polymer (I) is most preferably composed solely of the polymerized units (I).

[0414] In polymer (I), the content of polymerized units based on other monomers copolymerizable with the monomer represented by general formula (I) is, in order of decreasing preference, 99.0 mol% or less, 97.0 mol% or less, 95.0 mol% or less, 90 mol% or less, 80 mol% or less, 70 mol% or less, 60 mol% or less, 50 mol% or less, 40 mol% or less, 30 mol% or less, 20 mol% or less, and 10 mol% or less, based on all polymerized units. It is particularly preferred that the content of polymerized units based on other monomers copolymerizable with the monomer represented by general formula (I) is substantially 0 mol%, and it is most preferred that polymer (I) does not contain polymerized units based on other monomers.

[0415] In one embodiment, polymer (I) contains polymerization units (I) and polymerization units based on other monomers copolymerizable with monomer (I). When polymer (I) contains polymerization units (I) and polymerization units based on other monomers copolymerizable with monomer (I), the content of polymerization units (I) based on monomer (I) is preferably 50 to 94 mass%, more preferably 63 to 90 mass%, and even more preferably 67 to 87 mass%, based on all polymerization units constituting polymer (I), and the content of polymerization units based on other monomers is preferably 6 to 50 mass%, more preferably 10 to 37 mass%, and even more preferably 13 to 33 mass%, based on all polymerization units constituting polymer (I).

[0416] When the polymer (I) contains the polymerized units (I) and the polymerized units based on other monomers copolymerizable with the monomer (I), the alternation ratio of the polymerized units (I) and the polymerized units based on other monomers copolymerizable with the monomer (I) is preferably 40% or more, more preferably 50% or more, and even more preferably 60% or more. The alternation ratio may be, for example, 40 to 99%.

[0417] The alternation ratio of the polymerized unit (I) and the polymerized unit based on another monomer copolymerizable with the monomer (I) in the polymer (I) is 19 It can be determined by F-NMR analysis.

[0418] The lower limit of the weight average molecular weight (Mw) of the polymer (I) is, in order of preference, 0.2×10 4 That's 0.4 x 10 4 Above, 0.5 x 10 4 That's 0.6 x 10 4 That's 0.8 x 10 4 That's it, 1.0 x 10 4 That's it, 1.2 x 10 4 That's it, 1.4 x 10 4 That's 1.7 x 10 4 That's it, 1.9 x 10 4 That's it, 2.1 x 10 4 That's it, 2.3 x 10 4 That's it, 2.7 x 104 That's it, 3.1 x 10 4 That's it, 3.5 x 10 4 That's it, 3.9 x 10 4 That's it, 4.3 x 10 4 That's it, 4.7 x 10 4 That's it, 5.1 x 10 4 That's it, 10.0 x 10 4 That's it, 15.0 x 10 4 That's it, 20.0 x 10 4 That's it, 25.0 x 10 4 The upper limit of the weight average molecular weight (Mw) of the polymer (I) is, in order of decreasing preference, 150.0×10 4 Below, 100.0 x 10 4 Below, 60.0 x 10 4 Below, 50.0 x 10 4 Below, 40.0 x 10 4 The following is the result.

[0419] The lower limit of the number average molecular weight (Mn) of the polymer (I) is, in order of preference, 0.1 × 10 4 Above, 0.2 × 10 4 Above, 0.3 × 10 4 That's 0.4 x 10 4 Above, 0.5 x 10 4 That's 0.7 x 10 4 That's 0.8 x 10 4 That's it, 1.0 x 10 4 That's it, 1.2 x 10 4 That's it, 1.4 x 10 4 , 1.6×10 4 That's it, 1.8 x 10 4 That's it, 2.0 x 10 4 That's it, 3.0 x 10 4 The upper limit of the number average molecular weight (Mn) of the polymer (I) is, in order of preference, 75.0 × 10 4 Below, 50.0 x 10 4 Below, 40.0 x 10 4 Below, 30.0 x 10 4 Below, 20.0 x 10 4 The following is the result.

[0420] The molecular weight distribution (Mw / Mn) of the polymer (I) is, in order of preference, 3.0 or less, 2.4 or less, 2.2 or less, 2.0 or less, 1.9 or less, 1.7 or less, 1.5 or less, 1.4 or less, and 1.3 or less.

[0421] The number-average molecular weight and weight-average molecular weight are values ​​calculated by gel permeation chromatography (GPC) using monodisperse polyethylene oxide (PEO) or polyethylene glycol (PEG) as standards. Depending on the type of solvent used for GPC measurement, the molecular weight may also be calculated using monodisperse polystyrene as a standard. Furthermore, when GPC measurement is not possible, the number-average molecular weight of polymer (I) can be determined from the correlation between the number-average molecular weight calculated from the number of terminal groups obtained by NMR, FT-IR, etc. and the melt flow rate. The melt flow rate can be measured in accordance with JIS K 7210.

[0422] The polymer (I) typically has terminal groups. The terminal groups are generated during polymerization, and typical terminal groups are independently selected from hydrogen, iodine, bromine, linear or branched alkyl groups, and linear or branched fluoroalkyl groups, and may optionally contain at least one catenary heteroatom. The alkyl or fluoroalkyl group preferably has 1 to 20 carbon atoms. These terminal groups are generally generated from the initiator or chain transfer agent used to form the polymer (I), or are generated during the chain transfer reaction.

[0423] Preferably, polymer (I) has an ion exchange ratio (IXR) of 53 or less, where IXR is defined as the number of carbon atoms in the polymer backbone relative to the ionic group. Precursor groups that become ionic upon hydrolysis (e.g., -SOF) are not considered ionic groups for purposes of determining IXR.

[0424] IXR is preferably 0.5 or more, more preferably 0.7 or more, even more preferably 1.0 or more, even more preferably 1.2 or more, particularly preferably 1.5 or more, and particularly preferably 1.9 or more. IXR is more preferably 30 or less, more preferably 10 or less, particularly preferably 3 or less, and most preferably 2.2 or less.

[0425] The ion exchange capacity of polymer (I) is, in order of decreasing preference, 0.80 meq / g or more, 1.50 meq / g or more, 1.75 meq / g or more, 2.00 meq / g or more, 2.40 meq / g or more, 2.50 meq / g or more, 2.60 meq / g or more, 3.00 meq / g or more, 3.20 meq / g or more, and 3.50 meq / g or more. The ion exchange capacity is the content of ionic groups (-COOM) in polymer (I) and is calculated from the composition of polymer (I). Precursor groups that become ionic upon hydrolysis (e.g., -COOCH3) are not considered ionic groups for the purpose of determining the ion exchange capacity. It is presumed that a higher ion exchange capacity of polymer (I) results in more anionic groups in polymer (I), leading to the formation of highly stable particles, and a higher particle-forming ability, resulting in a higher number of particles per unit water volume, resulting in a higher polymerization rate. If the ion exchange capacity of the polymer (I) is too low, the fluorine-containing elastomer produced by polymerization may adhere to the polymerization vessel, a sufficient polymerization rate may not be obtained, or the number of fluorine-containing elastomer particles produced may be small.

[0426] In polymer (I), the ionic (anionic) groups are typically distributed along the polymer backbone. Polymer (I) comprises a polymer backbone with recurring side chains attached to the backbone, which preferably carry ionic groups.

[0427] Preferably, polymer (I) comprises ionic groups having a pKa of less than 10, more preferably less than 7. The ionic groups of polymer (I) are preferably selected from the group consisting of sulfonate, carboxylate, phosphonate, and phosphate.

[0428] The terms "sulfonate, carboxylate, phosphonate, and phosphate" are intended to refer to the respective salts or the respective acids capable of forming salts. When salts are used, preferably the salts are alkali metal or ammonium salts. A preferred ionic group is a sulfonate group.

[0429] The polymer (I) is preferably water-soluble. Water-soluble means the property of being easily dissolved or dispersed in an aqueous medium. The particle size of a water-soluble polymer cannot be measured by dynamic light scattering (DLS), for example, or the particle size is 10 nm or less.

[0430] The polymer (I) preferably has sufficient water solubility. Generally, the higher the content of the polymer (I) in the aqueous solution, the more difficult it becomes for the polymer (I) to be sufficiently dissolved or dispersed in the aqueous medium. Therefore, even when the content of the polymer (I) in the aqueous solution is high, if the particle size of the polymer (I) cannot be measured by dynamic light scattering (DLS), it can be said to be highly water soluble. It is preferable that the particle size of the polymer (I) cannot be measured even when it is contained in an aqueous solution at a content of 1.0% by mass. It is more preferable that the particle size of the polymer (I) cannot be measured even when it is contained in an aqueous solution at a content of 1.5% by mass, and even more preferably at a content of 2.0% by mass.

[0431] The viscosity of an aqueous solution of polymer (I) is preferably 5.0 mPa s or more, more preferably 8.0 mPa s or more, even more preferably 10.0 mPa s or more, particularly preferably 12.0 mPa s or more, and most preferably 14.0 mPa s or more, and preferably 100.0 mPa s or less, more preferably 50.0 mPa s or less, even more preferably 25.0 mPa s or less, and especially preferably 20.0 mPa s or less.

[0432] The viscosity of an aqueous solution of polymer (I) can be determined by adjusting the content of polymer (I) in the aqueous solution to 33 mass % based on the amount of the aqueous solution, and measuring the viscosity of the resulting aqueous solution at 20°C using a tuning fork vibro viscometer (model number: SV-10) manufactured by A&D Corporation.

[0433] The critical micelle concentration (CMC) of the polymer (I) is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, and preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less.

[0434] The critical micelle concentration of the polymer (I) can be determined by measuring the surface tension, for example, using a surface tensiometer CBVP-A3 manufactured by Kyowa Interface Science Co., Ltd.

[0435] The acid value of the polymer (I) is preferably 60 or more, more preferably 90 or more, even more preferably 120 or more, particularly preferably 150 or more, and most preferably 180 or more. The upper limit is not particularly limited, but is preferably 300 or less.

[0436] The acid value of the polymer (I) is determined by the presence of an anionic group other than an acid functional group, such as -COOM, -SO3M, -OSO3M, or -C(CF3)2OM (where M is a metal atom, NR 7 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 7 If the compound has an alkyl group (H or an organic group), these groups can be converted to acid groups (e.g., -COOH, -SO3H, etc.) and then measured by acid-base titration.

[0437] The polymer (I) is a polymer (11) of a monomer (11) represented by general formula (11), in which the content of polymerized units (11) based on the monomer (11) is 50 mol% or more based on all polymerized units constituting the polymer (11), and the weight average molecular weight (Mw) is 38.0 × 10 4 The polymer (11) described above can also be used. General formula (11): CX2=CY-CF2-O-Rf-A (In the formula, X and Y are independently H, F, CH3 or CF3, and at least one of X and Y is F. Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms or a fluorine-containing alkylene group having 2 to 100 carbon atoms and an ether bond. A is -COOM, -SO3M, -OSO3M or -C(CF3)2OM (M is H, a metal atom, NR 7 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 7 is H or an organic group.

[0438] In general formula (11), X and Y are independently H, F, CH3, or CF3, and at least one of X and Y is F. X is preferably H or F, and more preferably H. Y is preferably H or F, and more preferably F.

[0439] Rf and A in the general formula (11) are the same as Rf and A in the general formula (1) representing the monomer constituting the polymer (1).

[0440] The polymer (11) may be a homopolymer consisting of only polymerized units (11) based on the monomer (11), or may be a copolymer containing polymerized units (11) and polymerized units based on other monomers copolymerizable with the monomer (11). The other monomers are as described above. The polymerized units (11) may be the same or different in each occurrence, and the polymer (11) may contain polymerized units (11) based on two or more different monomers represented by the general formula (11).

[0441] The content of the polymerized units (11) in the polymer (11) is, in order of decreasing preference, 50 mol % or more, 60 mol % or more, 70 mol % or more, 80 mol % or more, 90 mol % or more, and 99 mol % or more of all the polymerized units constituting the polymer (11). The content of the polymerized units (11) is particularly preferably substantially 100 mol %, and it is most preferred that the polymer (11) consists solely of the polymerized units (11).

[0442] In polymer (11), the content of polymerized units based on other monomers copolymerizable with monomer (11) is, in order of decreasing preference, 99.0 mol% or less, 97.0 mol% or less, 95.0 mol% or less, 90 mol% or less, 80 mol% or less, 70 mol% or less, 60 mol% or less, and 50 mol% or less, based on all polymerized units constituting polymer (11). It is particularly preferred that the content of polymerized units based on other monomers copolymerizable with monomer (11) is substantially 0 mol%, and it is most preferred that polymer (11) does not contain polymerized units based on other monomers.

[0443] The lower limit of the weight average molecular weight of the polymer (11) is, in order of preference, 38.0×10 4 That's it, 40.0 x 10 4 The upper limit of the weight average molecular weight of the polymer (11) is, in order of preference, 150.0×10 4 Below, 100.0 x 10 4 Below, 60.0 x 10 4 is.

[0444] The lower limit of the number average molecular weight of the polymer (11) is, in order of preference, 5.0×10 4 , 8.0×10 4 , 10.0×10 4 That's it, 12.0 x 10 4 The upper limit of the number average molecular weight of the polymer (11) is, in order of preference, 75.0×10 4 Below, 50.0 x 10 4 Below, 40.0 x 10 4 Below, 30.0 x 10 4 The following is the result.

[0445] The polymer (I) is a polymer (12) of a monomer (12) represented by general formula (12), in which the content of polymerized units (12) based on the monomer (12) is 50 mol % or more based on all polymerized units constituting the polymer (12), and the weight average molecular weight (Mw) is 1.4 × 10 4 The polymer (12) described above can also be used. General formula (12): CX2=CX-O-Rf-A (In the formula, X is independently F or CF3, Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms, or a fluorine-containing alkylene group having 2 to 100 carbon atoms and an ether bond or a keto group, A is -COOM, -SO3M, -OSO3M, or -C(CF3)2OM (M is -H, a metal atom, -NR 7 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 7 is H or an organic group.

[0446] In general formula (12), X is independently F or CF3. It is preferable that at least one X is F, and it is more preferable that all X are F.

[0447] Rf and A in the general formula (12) are the same as Rf and A in the general formula (2) representing the monomer constituting the polymer (2).

[0448] The polymer (12) may be a homopolymer consisting of only polymerized units (12) based on the monomer (12), or may be a copolymer containing polymerized units (12) and polymerized units based on other monomers copolymerizable with the monomer (12). The other monomers are as described above. The polymerized units (12) may be the same or different in each occurrence, and the polymer (12) may contain polymerized units (12) based on two or more different monomers represented by the general formula (12).

[0449] The content of the polymerized units (12) in the polymer (12) is, in order of decreasing preference, 50 mol % or more, 60 mol % or more, 70 mol % or more, 80 mol % or more, 90 mol % or more, and 99 mol % or more of all the polymerized units constituting the polymer (12). The content of the polymerized units (12) is particularly preferably substantially 100 mol %, and it is most preferred that the polymer (12) consists solely of the polymerized units (12).

[0450] In polymer (12), the content of polymerized units based on other monomers copolymerizable with monomer (12) is, in order of decreasing preference, 50 mol % or less, 40 mol % or less, 30 mol % or less, 20 mol % or less, 10 mol % or less, and 1 mol % or less, based on all polymerized units constituting polymer (12). It is particularly preferred that the content of polymerized units based on other monomers copolymerizable with monomer (12) is substantially 0 mol %, and it is most preferred that polymer (12) does not contain polymerized units based on other monomers.

[0451] The lower limit of the weight average molecular weight (Mw) of the polymer (12) is, in order of preference, 1.4×10 4 That's 1.7 x 10 4 That's it, 1.9 x 10 4 That's it, 2.1 x 10 4 That's it, 2.3 x 10 4 That's it, 2.7 x 10 4 That's it, 3.1 x 10 4 That's it, 3.5 x 10 4 That's it, 3.9 x 10 4 That's it, 4.3 x 10 4 That's it, 4.7 x 10 4 That's it, 5.1 x 10 4 The upper limit of the weight average molecular weight (Mw) of the polymer (12) is, in order of decreasing preference, 150.0×10 4 Below, 100.0 x 10 4 Below, 60.0 x 10 4 Below, 50.0 x 10 4 Below, 40.0 x 10 4 The following is the result.

[0452] The lower limit of the number average molecular weight (Mn) of the polymer (12) is, in order of preference, 0.7×10 4 That's 0.9 x 10 4 That's it, 1.0 x 10 4 That's it, 1.2 x 10 4 That's it, 1.4 x 10 4 That's it, 1.6 x 10 4 That's it, 1.8 x 10 4 The upper limit of the number average molecular weight (Mn) of the polymer (12) is, in order of preference, 75.0×10 4 Below, 50.0 x 10 4 Below, 40.0 x 10 4 Below, 30.0 x 10 4 Below, 20.0 x 10 4 The following is the result.

[0453] The molecular weight distribution (Mw / Mn) of the polymer (12) is preferably 3.0 or less, more preferably 2.4 or less, even more preferably 2.2 or less, particularly preferably 2.0 or less, and most preferably 1.9 or less.

[0454] As the polymer (I), a polymer (13) of a monomer (13) represented by general formula (13), in which the content of polymerization units (13) based on the monomer (13) is 50 mass% or more based on all polymerization units constituting the polymer (13), can also be used. General formula (13): CX2=CX-O-Rf-SO3M (In the formula, X is independently F or CF3, Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms or a fluorine-containing alkylene group having 2 to 100 carbon atoms and having an ether bond or a keto group, M is —H, a metal atom, —NR 7 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 7 is H or an organic group.

[0455] In general formula (13), X is independently F or CF3. It is preferable that at least one X is F, and it is more preferable that all X are F.

[0456] Rf and M in the general formula (13) are the same as Rf and M in the general formula (2) representing the monomer constituting the polymer (2).

[0457] The polymer (13) may be a homopolymer consisting of only polymerized units (13) based on the monomer (13), or may be a copolymer containing polymerized units (13) and polymerized units based on other monomers copolymerizable with the monomer (13). The other monomers are as described above. The polymerized units (13) may be the same or different in each occurrence, and the polymer (13) may contain polymerized units (13) based on two or more different monomers represented by the general formula (13).

[0458] The content of polymerized units (13) based on monomer (13) in polymer (13) is 50% by mass or more, based on all polymerized units constituting polymer (13). The content of polymerized units (13) in polymer (13) is, in order of decreasing preference, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, and 99% by mass or more, based on all polymerized units constituting polymer (13). It is particularly preferable that the content of polymerized units (13) is substantially 100% by mass, and it is most preferable that polymer (13) consists solely of polymerized units (13).

[0459] In polymer (13), the content of polymerized units based on other monomers copolymerizable with monomer (13) is, in order of decreasing preference, 50% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less, 10% by mass or less, and 1% by mass or less, based on all polymerized units constituting polymer (13). It is particularly preferred that the content of polymerized units based on other monomers copolymerizable with monomer (13) is substantially 0% by mass, and it is most preferred that polymer (13) does not contain polymerized units based on other monomers.

[0460] The lower limit of the number average molecular weight of the polymer (13) is, in order of preference, 0.3 × 10 4 That's 0.4 x 10 4 Above, 0.5 x 10 4 That's 0.7 x 10 4 That's 0.8 x 10 4 That's it, 1.0 x 10 4 That's it, 1.2 x 10 4 That's it, 1.4 x 10 4 , 1.6×10 4 That's it, 1.8 x 10 4 That's it, 2.0 x 10 4 That's it, 3.0 x 10 4 The upper limit of the number average molecular weight of the polymer (13) is, in order of preference, 75.0 × 10 4 Below, 50.0 x 10 4 Below, 40.0 x 10 4 Below, 30.0 x 10 4 Below, 20.0 x 10 4 The following is the result.

[0461] The lower limit of the weight average molecular weight of the polymer (13) is, in order of preference, 0.4×10 4 Above, 0.5 x 10 4 That's 0.6 x 10 4 That's 0.8 x 10 4 That's it, 1.0 x 10 4 That's it, 1.2 x 10 4 That's it, 1.4 x 10 4 That's 1.7 x 10 4 That's it, 1.9 x 10 4 That's it, 2.1 x 10 4 That's it, 2.3 x 10 4 That's it, 2.7 x 10 4 That's it, 3.1 x 10 4 That's it, 3.5 x 10 4 That's it, 3.9 x 10 4 That's it, 4.3 x 10 4 That's it, 4.7 x 10 4 That's it, 5.1 x 10 4 That's it, 10.0 x 10 4 That's it, 15.0 x 10 4 That's it, 20.0 x 10 4 That's it, 25.0 x 10 4The upper limit of the weight average molecular weight of the polymer (13) is, in order of preference, 150.0×10 4 Below, 100.0 x 10 4 Below, 60.0 x 10 4 Below, 50.0 x 10 4 Below, 40.0 x 10 4 The following is the result.

[0462] The molecular weight distribution (Mw / Mn) of the polymer (13) is preferably 3.0 or less, 2.4 or less, 2.2 or less, 2.0 or less, 1.9 or less, 1.7 or less, 1.5 or less, 1.4 or less, and 1.3 or less.

[0463] The polymer (I) can be produced by a conventionally known method except for using the above-mentioned monomers.

[0464] Among the polymers (I), the polymer (11) can be produced by a production method (11) for producing a polymer (11) from the monomer (11) by polymerizing the monomer (11) represented by the general formula (11) in an aqueous medium, wherein the oxygen concentration in the polymerization reaction system is maintained at 500 ppm by volume or less.

[0465] In the production method (11), the oxygen concentration in the polymerization reaction system is 500 ppm by volume or less. In the production method (11), the oxygen concentration in the reaction system is maintained at 500 ppm by volume or less throughout the entire polymerization period of the monomer (11). The oxygen concentration in the reaction system is preferably 350 ppm by volume or less, more preferably 300 ppm by volume or less, even more preferably 100 ppm by volume or less, and particularly preferably 50 ppm by volume or less. In addition, the oxygen concentration in the reaction system is usually 0.01 ppm by volume or more.

[0466] In the production method (11), the polymerization temperature of the monomer (11) is preferably 59°C or lower, more preferably 57°C or lower, even more preferably 55°C or lower, and particularly preferably 53°C or lower, because a polymer (11) having a higher molecular weight can be easily produced. The polymerization temperature is preferably 20°C or higher, more preferably 25°C or higher, even more preferably 30°C or higher, and particularly preferably 35°C or higher.

[0467] In the production method (11), the monomer (11) may be copolymerized with the other monomers described above.

[0468] In the production method (11), the polymerization pressure is usually from atmospheric pressure to 10 MPaG, and is appropriately determined depending on the type of monomer used, the molecular weight of the target polymer, and the reaction rate.

[0469] In the production method (11), the polymerization time is usually 1 to 200 hours, and may be 5 to 100 hours.

[0470] Among the polymers (I), the polymer (12) can be produced by a production method (12) for producing a polymer (12) from the monomer (12) by polymerizing the monomer (12) represented by the general formula (12) in an aqueous medium, wherein the oxygen concentration in the polymerization reaction system is maintained at 1500 ppm by volume or less.

[0471] In the production method (12), the oxygen concentration in the polymerization reaction system is 1500 ppm by volume or less. In the production method (12), the oxygen concentration in the reaction system is maintained at 1500 ppm by volume or less throughout the entire polymerization period of the monomer (12). The oxygen concentration in the reaction system is preferably 500 ppm by volume or less, more preferably 100 ppm by volume or less, and even more preferably 50 ppm by volume or less. In addition, the oxygen concentration in the reaction system is usually 0.01 ppm by volume or more.

[0472] In the production method (12), the polymerization temperature of the monomer (12) is preferably 70°C or lower, more preferably 65°C or lower, even more preferably 60°C or lower, particularly preferably 55°C or lower, even more preferably 50°C or lower, particularly preferably 45°C or lower, most preferably 40°C or lower, preferably 10°C or higher, more preferably 15°C or higher, and even more preferably 20°C or higher, since this facilitates the production of a polymer (12) having a higher molecular weight.

[0473] In the production method (12), the monomer (12) may be copolymerized with the other monomers described above.

[0474] In the production method (12), the polymerization pressure is usually from atmospheric pressure to 10 MPaG, and is appropriately determined depending on the type of monomer used, the molecular weight of the target polymer, and the reaction rate.

[0475] In the production method (12), the polymerization time is usually 1 to 200 hours, and may be 5 to 100 hours.

[0476] Of the polymers (1), the polymer (13) can be produced by a method (13) for producing a polymer (13) by polymerizing a monomer (13) represented by general formula (13) in an aqueous medium to produce a polymer (13) of the monomer (13).

[0477] In the production method (13), the oxygen concentration in the polymerization reaction system is preferably 1500 volume ppm or less, more preferably 500 volume ppm or less, even more preferably 100 volume ppm or less, and particularly preferably 50 volume ppm or less. The oxygen concentration in the reaction system is usually 0.01 volume ppm or more. In the above production method, it is preferred that the oxygen concentration in the reaction system be maintained within the above range throughout the entire polymerization period of the monomer (13).

[0478] In the production method (13), the polymerization temperature of the monomer (13) is preferably 70°C or less, more preferably 65°C or less, even more preferably 60°C or less, particularly preferably 55°C or less, even more preferably 50°C or less, particularly preferably 45°C or less, most preferably 40°C or less, preferably 10°C or more, more preferably 15°C or more, and even more preferably 20°C or more, since this facilitates the production of a polymer (13) having a higher molecular weight.

[0479] In the production method (13), the monomer (13) may be copolymerized with the other monomers described above.

[0480] In the production method (13), the polymerization pressure is usually from atmospheric pressure to 10 MPaG, and is appropriately determined depending on the type of monomer used, the molecular weight of the target polymer, and the reaction rate.

[0481] In the production method (13), the polymerization time is usually 1 to 200 hours, and may be 5 to 100 hours.

[0482] In the production methods (11) to (13), the oxygen concentration in the polymerization reaction system can be controlled, for example, by flowing an inert gas such as nitrogen or argon, or, when a gaseous monomer is used, the gaseous monomer, through the liquid or gas phase in the reactor. The oxygen concentration in the polymerization reaction system can be determined by measuring and analyzing the gas coming out of the exhaust gas line of the polymerization system with a low-concentration oxygen analyzer.

[0483] In the production methods (11) to (13), the aqueous medium is a reaction medium for polymerization and refers to a liquid containing water. The aqueous medium is not particularly limited as long as it contains water, and may contain water and, for example, a fluorine-free organic solvent such as an alcohol, ether, or ketone, and / or a fluorine-containing organic solvent having a boiling point of 40°C or lower. Water is preferred as the aqueous medium.

[0484] In the production methods (11) to (13), the polymerization of the monomers can be carried out in the presence of a polymerization initiator. The polymerization initiator is not particularly limited as long as it can generate radicals within the above-mentioned polymerization temperature range, and known oil-soluble and / or water-soluble polymerization initiators can be used. Furthermore, the polymerization can be initiated as a redox reaction by combining with a reducing agent or the like. The concentration of the polymerization initiator is determined appropriately depending on the type of monomer, the molecular weight of the target polymer, and the reaction rate.

[0485] As the polymerization initiator, persulfates (e.g., ammonium persulfate), or organic peroxides such as disuccinic acid peroxide and diglutaric acid peroxide can be used alone or in the form of a mixture thereof. They may also be used in combination with a reducing agent such as sodium sulfite to form a redox system. Furthermore, during polymerization, a radical scavenger such as hydroquinone or catechol, or a peroxide decomposer such as ammonium sulfite, can be added to adjust the radical concentration in the system.

[0486] As the polymerization initiator, persulfates are particularly preferred because they can easily produce polymers with higher molecular weights. Examples of persulfates include ammonium persulfate, potassium persulfate, and sodium persulfate, with ammonium persulfate being preferred.

[0487] The amount of polymerization initiator to be added is not particularly limited, but may be added all at once, stepwise, or continuously at the beginning of polymerization in an amount (for example, several ppm relative to the water concentration) that does not significantly decrease the polymerization rate. The upper limit is a range in which the reaction temperature can be increased while removing heat from the equipment using the heat of polymerization reaction, and a more preferred upper limit is a range in which the heat of polymerization reaction can be removed from the equipment.

[0488] In the production methods (11) to (13), the polymerization initiator can be added not only at the start of polymerization but also during polymerization. The ratio of the amount of polymerization initiator added at the start of polymerization to the amount of polymerization initiator added during polymerization is preferably 95 / 5 to 5 / 95, more preferably 60 / 40 to 10 / 90, and even more preferably 30 / 70 to 15 / 85. The method of adding the polymerization initiator during polymerization is not particularly limited, and the entire amount may be added at once, or may be added in two or more divided portions, or may be added continuously.

[0489] In the production methods (11) to (13), since polymers with higher molecular weights can be easily produced, the total amount of polymerization initiators used in the polymerization is preferably 0.00001 to 10% by mass relative to the aqueous medium. The total amount of polymerization initiators used in the polymerization is more preferably 0.0001% by mass or more, even more preferably 0.001% by mass or more, particularly preferably 0.01% by mass or more, more preferably 5% by mass or less, and even more preferably 2% by mass or less.

[0490] In the production methods (11) to (13), since polymers with higher molecular weights can be easily produced, the total amount of polymerization initiators used in the polymerization is preferably 0.001 to 10 mol% based on the monomers. The total amount of polymerization initiators used in the polymerization is more preferably 0.005 mol% or more, even more preferably 0.01 mol% or more, particularly preferably 0.1 mol% or more, most preferably 0.5 mol% or more, more preferably 5 mol% or less, even more preferably 2.5 mol% or less, particularly preferably 2.2 mol% or less, and most preferably 2.0 mol% or less.

[0491] In the production methods (11) to (13), since polymers with higher molecular weights can be easily produced, the amount of monomer containing any one of the monomers (11) to (13) present at the start of polymerization is preferably 20% by mass or more relative to the amount of aqueous medium present. The amount of the monomer present is more preferably 30% by mass or more, and even more preferably 40% by mass or more. There are no particular restrictions on the upper limit of the amount of the monomer present, but from the viewpoint of smoothly progressing the polymerization, it may be 200% by mass or less. The amount of the monomer present at the start of polymerization refers to the total amount present of any one of the monomers (11) to (13) and, if present, other monomers present in the reactor at the start of polymerization.

[0492] In the production methods (11) to (13), the polymerization may be carried out in the presence of a pH adjuster, which may be added before or after the start of the polymerization.

[0493] Examples of pH adjusters that can be used include ammonia, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, ammonium carbonate, sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, sodium phosphate, potassium phosphate, sodium citrate, potassium citrate, ammonium citrate, sodium gluconate, potassium gluconate, and ammonium gluconate.

[0494] In the production methods (11) to (13), the polymerization of the monomers (11) to (13) can be carried out by charging a reactor with an aqueous medium, the monomers (11) to (13), and, if necessary, other monomers and other additives, stirring the contents of the reactor, maintaining the reactor at a predetermined polymerization temperature, and then adding a predetermined amount of polymerization initiator to initiate the polymerization reaction. After the start of the polymerization reaction, the monomers, polymerization initiator, and other additives may be added depending on the purpose.

[0495] In the production methods (11) to (13), the polymerization of the monomers can be carried out substantially in the absence of a fluorinated surfactant. In the present disclosure, "substantially in the absence of a fluorinated surfactant" means that the amount of the fluorinated surfactant relative to the aqueous medium is 10 ppm by mass or less. The amount of the fluorinated surfactant relative to the aqueous medium is preferably 1 ppm by mass or less, more preferably 100 ppb by mass or less, even more preferably 10 ppb by mass or less, and even more preferably 1 ppb by mass or less.

[0496] The fluorine-containing surfactant will be described later as a "fluorine-containing surfactant having no functional group reactive by radical polymerization."

[0497] In the production method of the present disclosure, the amount of polymer (I) added is preferably 0.00001 to 20% by mass relative to 100% by mass of the aqueous medium. By setting the amount of polymer (I) added (abundance) in the polymerization within the above range, the polymerization reaction of the fluorine-containing monomer proceeds smoothly, and a fluorine-containing elastomer can be produced efficiently. If the amount of polymer (I) added is too small, a sufficient polymerization rate or a sufficient yield may not be obtained.

[0498] The amount of polymer (I) added is more preferably 0.0001% by mass or more, even more preferably 0.0005% by mass or more, still more preferably 0.001% by mass or more, particularly preferably 0.005% by mass or more, and most preferably 0.01% by mass or more, relative to 100% by mass of the aqueous medium, because this allows the polymerization reaction of the fluorine-containing monomer to proceed more smoothly.

[0499] Furthermore, if the amount of polymer (I) added is too large, an effect commensurate with the amount added will not be obtained, which is economically disadvantageous. Therefore, the amount of polymer (I) added is more preferably 2% by mass or less, even more preferably 1% by mass or less, and particularly preferably 0.5% by mass or less, relative to 100% by mass of the aqueous medium.

[0500] The timing of adding polymer (I) in the above polymerization is not particularly limited, and it may be added before or after the start of polymerization. Furthermore, in the above polymerization, polymer (I) may be added all at once or continuously at any time. Continuous addition of polymer (I) means, for example, adding polymer (I) over time, without interruption or in portions, rather than all at once. When polymer (I) is added continuously, it is preferable to add it so that the total amount of polymer (I) added falls within the above-mentioned range. When polymer (I) is added, an aqueous solution containing polymer (I) and water may be prepared, and the aqueous solution may be added.

[0501] As the polymer (I), an aqueous solution containing the polymer (I) can be used.

[0502] The polymer (I) or an aqueous solution containing the polymer (I) may contain dimers and trimers of the monomer (1), or may be substantially free of dimers and trimers of the monomer (1). The dimers and trimers of the monomer (1) are usually generated when the monomer (1) is polymerized to obtain the polymer (I). The content of dimers and trimers in the polymer (I) or in an aqueous solution containing the polymer (I) is 1.0% by mass or less, preferably 0.1% by mass or less, more preferably 0.01% by mass or less, even more preferably 0.001% by mass or less, and particularly preferably 0.0001% by mass or less, based on the polymer (I).

[0503] The polymer (I) or an aqueous solution containing the polymer (I) may be substantially free of dimers and trimers composed of polymerization units (1) derived from the monomer (1) and polymerization units derived from other monomers copolymerizable with the monomer (1). The dimers and trimers composed of polymerization units (1) and polymerization units derived from other monomers are usually generated when the polymer (1) is obtained by polymerizing the monomer (1) with other monomers copolymerizable with the monomer (1). The content of the dimers and trimers composed of polymerization units (1) and polymerization units derived from other monomers in the polymer (1) is 1.0% by mass or less, preferably 0.1% by mass or less, more preferably 0.01% by mass or less, even more preferably 0.001% by mass or less, and particularly preferably 0.0001% by mass or less, based on the polymer (1).

[0504] The contents of dimers and trimers in polymer (I) or in an aqueous solution containing polymer (I) can be determined by performing gel permeation chromatography (GPC) analysis of polymer (I) and calculating the ratio (area percentage) of the total peak area of ​​dimers and trimers to the total area of ​​each peak in the chromatogram obtained by GPC analysis.

[0505] Furthermore, when the content of dimers and trimers in polymer (I) or in an aqueous solution containing polymer (I) is less than 0.5 mass % relative to polymer (I), they can be identified by measurement using liquid chromatography-mass spectrometry (LC / MS). Specifically, aqueous solutions containing five or more levels of polymer (I) are prepared, and LC / MS analysis is performed for each content. The relationship between the content and the area (peak integral value) for each content is plotted to create a calibration curve for polymer (I). Furthermore, calibration curves for the dimer and trimer of polymer (I) are created from the calibration curve for polymer (I). Methanol is added to the polymer (I) to prepare a mixture, which is then filtered using an ultrafiltration disk (molecular weight cutoff: 3000 Da), and the resulting recovered liquid is subjected to LC / MS analysis. Then, using the calibration curve, the area (integrated value of the peak) of the chromatogram of the dimer and trimer of polymer (I) can be converted into the contents of the dimer and trimer.

[0506] The dimers and trimers in the polymer (I) or in an aqueous solution containing the polymer (I) can be removed by treating the aqueous solution containing the polymer (I) by at least one means selected from the group consisting of ultrafiltration, microfiltration, dialysis membrane treatment, liquid separation, and reprecipitation.

[0507] In the production method of the present disclosure, it is preferable that a fluorine-containing monomer is polymerized substantially in the absence of a fluorine-containing surfactant having no functional group capable of reacting by radical polymerization (hereinafter, may be simply referred to as a "fluorine-containing surfactant").

[0508] Conventionally, a fluorine-containing surfactant has been used for the polymerization of a fluorine-containing monomer, but the production method of the present disclosure makes it possible to obtain a fluorine-containing elastomer by polymerizing a fluorine-containing monomer without using a fluorine-containing surfactant by using a fluorine-containing compound (A) and a polymer (I).

[0509] In the present disclosure, "in the substantial absence of a fluorine-containing surfactant having no functional group reactive by radical polymerization" means that the content of the fluorine-containing surfactant relative to the aqueous medium is 10 ppm by mass or less, and the content of the fluorine-containing surfactant is preferably 1 ppm by mass or less, more preferably 100 ppb by mass or less, even more preferably 10 ppb by mass or less, and particularly preferably 1 ppb by mass or less.

[0510] The fluorine-containing surfactant may, for example, be an anionic fluorine-containing surfactant.

[0511] The anionic fluorine-containing surfactant may be, for example, a surfactant containing fluorine atoms and having a total carbon number of 20 or less excluding the anionic group.

[0512] The fluorine-containing surfactant may also be a surfactant containing fluorine in the anionic moiety having a molecular weight of 1,000 or less, preferably 800 or less.

[0513] The "anionic portion" refers to the portion of the fluorine-containing surfactant excluding the cation. For example, F(CF2) represented by the formula (I) described below n1 In the case of COOM, "F(CF2) n1 The "COO" part.

[0514] The above-mentioned fluorine-containing surfactant also includes a fluorine-containing surfactant having a LogPOW of not more than 3.5. The LogPOW is a partition coefficient between 1-octanol and water, and is expressed as LogP (where P represents the ratio of the fluorine-containing surfactant concentration in octanol to the fluorine-containing surfactant concentration in water when a 1:1 octanol / water mixture containing the fluorine-containing surfactant undergoes phase separation).

[0515] The LogPOW is calculated from the HPLC elution time of the sample solution using standard substances (heptanoic acid, octanoic acid, nonanoic acid, and decanoic acid) with known octanol / water partition coefficients under the following conditions: column: TOSOH ODS-120T column (φ4.6 mm×250 mm, manufactured by Tosoh Corporation), eluent: acetonitrile / 0.6% by mass HClO₄ water = 1 / 1 (vol / vol%), flow rate: 1.0 mL / min, sample amount: 300 μL, column temperature: 40°C, detection light: UV 210 nm. A calibration curve between each elution time and the known octanol / water partition coefficient is then prepared, and the LogPOW is calculated from the HPLC elution time of the sample solution based on this calibration curve.

[0516] Specific examples of the fluorine-containing surfactants include those described in U.S. Patent Application Publication Nos. 2007 / 0015864, 2007 / 0015865, 2007 / 0015866, 2007 / 0276103, 2007 / 0117914, 2007 / 0142541, 2008 / 0015319, and U.S. Patent No. 3,250,808. No. 3,271,341, JP 2003-119204 A, WO 2005 / 042593, WO 2008 / 060461, WO 2007 / 046377, JP 2007-119526 A, WO 2007 / 046482, WO 2007 / 046345, U.S. Patent Application Publication No. 2014 / 0228531, WO 2013 / 189824, and WO 2013 / 189826.

[0517] The anionic fluorine-containing surfactant may be a compound represented by the following general formula (N 0 ): X n0 -Rf n0 -Y 0 (N 0 ) (In the formula, X n0 is H, Cl or F. n0 is a linear, branched or cyclic alkylene group having 3 to 20 carbon atoms, in which some or all of the H atoms have been substituted with F, and the alkylene group may contain one or more ether bonds, and some of the H atoms may have been substituted with Cl. Y 0 is an anionic group.

[0518] Y 0 The anionic group may be -COOM, -SO2M, or -SO3M, and may be -COOM or -SO3M.

[0519] M is H, metal atom, NR 74. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 7 is —H or an organic group.

[0520] The metal atom includes alkali metals (Group 1) and alkaline earth metals (Group 2), such as Na, K, or Li.

[0521] R 7 As -H or C 1-10 and may be an organic group of the formula: -H or C 1-4 and may be an organic group of the formula: -H or C 1-4 The alkyl group may be:

[0522] M is H, a metal atom, or NR 7 4, and may be H, an alkali metal (Group 1), an alkaline earth metal (Group 2), or NR 7 4, which may be H, Na, K, Li or NH4.

[0523] Above Rf n0 may be one in which 50% or more of H is substituted with fluorine.

[0524] The general formula (N 0 ) as a compound represented by The following general formula (N 1 ): X n0 -(CF2) m1 -Y 0 (N 1 ) (In the formula, X n0 is H, Cl, and F, m1 is an integer from 3 to 15, and Y 0 is as defined above, a compound represented by the following general formula (N 2 ): Rf n1 -O-(CF(CF3)CF2O) m2 CFX n1 -Y 0 (N 2 ) (In the formula, Rf n1 is a perfluoroalkyl group having 1 to 5 carbon atoms, m2 is an integer of 0 to 3, and X n1 is F or CF3, and Y 0 is as defined above, a compound represented by the following general formula (N 3 ): Rf n2 (CH2) m3 -(Rf n3 ) q -Y 0 (N 3 ) (In the formula, Rf n2 is a partially or fully fluorinated alkyl group having 1 to 13 carbon atoms, which may contain an ether bond and / or a chlorine atom, m3 is an integer of 1 to 3, and Rf n3 is a linear or branched perfluoroalkylene group having 1 to 3 carbon atoms, q is 0 or 1, and Y 0 is as defined above, a compound represented by the following general formula (N 4 ): Rf n4 -O-(CY n1 Y n2 ) p CF2-Y 0 (N 4 ) (In the formula, Rf n4 is a linear or branched partially or fully fluorinated alkyl group having 1 to 12 carbon atoms, which may contain an ether bond; Y n1 and Y n2 are the same or different and are H or F, p is 0 or 1, and Y 0 is as defined above, and a compound represented by the following general formula (N 5 ): [ka] (In the formula, X n2 , X n3 and X n4 Rf may be the same or different and are H, F, or a linear or branched partially or fully fluorinated alkyl group having 1 to 6 carbon atoms, which may contain an ether bond.n5 is a linear or branched partially or fully fluorinated alkylene group having 1 to 3 carbon atoms, which may contain an ether bond; L is a linking group; Y 0 is as defined above, where X n2 , X n3 , X n4 and Rf n5 The total number of carbon atoms is 18 or less.

[0525] The general formula (N 0 ) More specifically, the compounds represented by the formula (I) include perfluorocarboxylic acids (I) represented by the following general formula (I), ω-H perfluorocarboxylic acids (II) represented by the following general formula (II), perfluoroethercarboxylic acids (III) represented by the following general formula (III), perfluoroalkyl alkylenecarboxylic acids (IV) represented by the following general formula (IV), perfluoroalkoxy fluorocarboxylic acids (V) represented by the following general formula (V), perfluoroalkyl sulfonic acids (VI) represented by the following general formula (VII), ω-H perfluorosulfonic acids (VII) represented by the following general formula (VII), perfluoroalkyl alkylene sulfonic acids (VIII) represented by the following general formula (VIII), alkyl alkylene carboxylic acids (IX) represented by the following general formula (IX), fluorocarboxylic acids (X) represented by the following general formula (X), alkoxy fluorosulfonic acids (XI) represented by the following general formula (XI), compounds (XII) represented by the following general formula (XII), and compounds (XIII) represented by the following general formula (XIII).

[0526] The perfluorocarboxylic acid (I) is represented by the following general formula (I): F(CF2) n1 COOM (I) (wherein n1 is an integer of 3 to 14, and M is H, a metal atom, or NR 7 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 7 is -H or an organic group.

[0527] The ω-H perfluorocarboxylic acid (II) is represented by the following general formula (II): H(CF2) n2 COOM (II) (wherein n2 is an integer of 4 to 15, and M is as defined above).

[0528] The perfluoroether carboxylic acid (III) is represented by the following general formula (III): Rf 1 -O-(CF(CF3)CF2O) n3 CF(CF3)COOM (III) (In the formula, Rf 1 is a perfluoroalkyl group having 1 to 5 carbon atoms, n3 is an integer of 0 to 3, and M is as defined above.

[0529] The perfluoroalkyl alkylene carboxylic acid (IV) is represented by the following general formula (IV): Rf 2 (CH2) n4 Rf 3 COOM (IV) (In the formula, Rf 2 is a perfluoroalkyl group having 1 to 5 carbon atoms, and Rf 3 is a linear or branched perfluoroalkylene group having 1 to 3 carbon atoms, n4 is an integer of 1 to 3, and M is as defined above.

[0530] The alkoxyfluorocarboxylic acid (V) is represented by the following general formula (V): Rf 4 -O-CY 1 Y 2 CF2-COOM (V) (In the formula, Rf 4 is a linear or branched partially or fully fluorinated alkyl group having 1 to 12 carbon atoms, which may contain an ether bond and / or a chlorine atom, and Y 1 and Y 2are the same or different and are H or F, and M is as defined above.

[0531] The perfluoroalkylsulfonic acid (VI) is represented by the following general formula (VI): F(CF2) n5 SO3M (VI) (wherein n5 is an integer of 3 to 14, and M is as defined above).

[0532] The ω-H perfluorosulfonic acid (VII) is represented by the following general formula (VII): H(CF2) n6 SO3M (VII) (wherein n6 is an integer of 4 to 14, and M is as defined above).

[0533] The perfluoroalkyl alkylene sulfonic acid (VIII) is represented by the following general formula (VIII): Rf 5 (CH2) n7 SO3M (VIII) (In the formula, Rf 5 is a perfluoroalkyl group having 1 to 13 carbon atoms, n7 is an integer of 1 to 3, and M is as defined above.

[0534] The alkyl alkylene carboxylic acid (IX) is represented by the following general formula (IX): Rf 6 (CH2) n8 COOM (IX) (In the formula, Rf 6 is a linear or branched partially or fully fluorinated alkyl group having 1 to 13 carbon atoms which may contain an ether bond, n8 is an integer from 1 to 3, and M is as defined above.

[0535] The fluorocarboxylic acid (X) is represented by the following general formula (X): Rf 7 -O-Rf 8-O-CF2-COOM (X) (In the formula, Rf 7 is a linear or branched partially or fully fluorinated alkyl group having 1 to 6 carbon atoms, which may contain an ether bond and / or a chlorine atom, and Rf 8 is a linear or branched, partially or fully fluorinated alkyl group having 1 to 6 carbon atoms, and M is as defined above.

[0536] The alkoxyfluorosulfonic acid (XI) is represented by the following general formula (XI): Rf 9 -O-CY 1 Y 2 CF2-SO3M (XI) (In the formula, Rf 9 is a linear or branched alkyl group having 1 to 12 carbon atoms, which may contain an ether bond, and which may contain chlorine, and which is partially or completely fluorinated; Y 1 and Y 2 are the same or different and are H or F, and M is as defined above.

[0537] The compound (XII) is represented by the following general formula (XII): [ka] (In the formula, X 1 , X 2 and X 3 Rf may be the same or different and are H, F, and linear or branched partially or fully fluorinated alkyl groups having 1 to 6 carbon atoms, which may contain ether bonds; 10 is a perfluoroalkylene group having 1 to 3 carbon atoms, L is a linking group, and Y 0 is an anionic group.

[0538] Y 0 may be -COOM, -SO2M, or -SO3M, and may be -SO3M or -COOM (wherein M is as defined above).

[0539] Examples of L include a single bond, and a partially or fully fluorinated alkylene group having 1 to 10 carbon atoms which may contain an ether bond.

[0540] The compound (XIII) is represented by the following general formula (XIII): Rf 11 -O-(CF2CF(CF3)O) n9 (CF2O) n10 CF2COOM (XIII) (In the formula, Rf 11 is a fluoroalkyl group containing chlorine and having 1 to 5 carbon atoms, n9 is an integer of 0 to 3, n10 is an integer of 0 to 3, and M is as defined above. Compound (XIII) is represented by the formula: CF2ClO(CF2CF(CF3)O) n9 (CF2O) n10 CF2COONH4 (a mixture having an average molecular weight of 750, wherein n9 and n10 are defined above).

[0541] The fluorine-containing surfactant may be one type of fluorine-containing surfactant or a mixture containing two or more types of fluorine-containing surfactants.

[0542] Examples of the fluorine-containing surfactant include compounds represented by the following formula: The fluorine-containing surfactant may be a mixture of these compounds: In one embodiment of the above polymerization, the fluoromonomer is polymerized substantially in the absence of a compound represented by the following formula: F(CF2)7COOM, F(CF2)5COOM, H(CF2)6COOM, H(CF2)7COOM, CF3O(CF2)3OCHFCF2COOM, C3F7OCF(CF3)CF2OCF(CF3)COOM, CF3CF2CF2OCF(CF3)COOM, CF3CF2OCF2CF2OCF2COOM, C2F5OCF(CF3)CF2OCF(CF3)COOM, CF3OCF(CF3)CF2OCF(CF3)COOM, CF2ClCF2CF2OCF(CF3)CF2OCF2COOM, CF2ClCF2CF2OCF2CF(CF3)OCF2COOM, CF2ClCF(CF3)OCF(CF3)CF2OCF2COOM, CF2ClCF(CF3)OCF2CF(CF3)OCF2COOM, [ka] (In each formula, M is H, metal atom, NR 7 4. An imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent. 7 is H or an organic group.

[0543] In the production method of the present disclosure, polymerization may be carried out in the presence of a polymerization initiator.

[0544] In the production method of the present disclosure, the polymerization of the fluorine-containing monomer can be carried out, for example, by charging compound (A), polymer (I), and an aqueous medium into a pressure-resistant polymerization vessel equipped with a stirrer, deoxidizing, then charging the monomers, bringing the temperature to a predetermined value, and adding a polymerization initiator to initiate the reaction. As the pressure decreases as the reaction proceeds, additional monomer is continuously or intermittently fed to maintain the initial pressure. Once a predetermined amount of monomer has been fed, the feed is stopped, the monomer in the reaction vessel is purged, and the temperature is returned to room temperature to terminate the reaction.

[0545] The polymerization initiator may be a radical polymerization initiator. The polymerization initiator is not particularly limited as long as it can generate radicals at the temperature at which the fluorine-containing monomer is polymerized, and an oil-soluble polymerization initiator, a water-soluble polymerization initiator, or the like can be used, with a water-soluble polymerization initiator being preferred. The polymerization initiator may also be used as a redox initiator in combination with a reducing agent or the like.

[0546] The amount of polymerization initiator used in polymerizing a fluorine-containing monomer is appropriately determined depending on the type of monomer, the molecular weight of the target fluorine-containing elastomer, and the reaction rate. The amount of polymerization initiator is appropriately determined depending on the molecular weight of the target fluorine-containing elastomer and the polymerization reaction rate, and is preferably 0.00001 to 10% by mass, and more preferably 0.0001 to 1% by mass, based on 100% by mass of the total amount of monomers.

[0547] As the polymerization initiator, an oil-soluble radical polymerization initiator, a water-soluble radical polymerization initiator, or an azo compound can be used.

[0548] The oil-soluble radical polymerization initiator may be a known oil-soluble peroxide, for example, dialkyl peroxycarbonates such as diisopropyl peroxydicarbonate and di-sec-butyl peroxydicarbonate, peroxyesters such as t-butyl peroxyisobutyrate and t-butyl peroxypivalate, dialkyl peroxides such as di-t-butyl peroxide, and the like. Also usable are di(ω-hydro-dodecafluoroheptanoyl) peroxide, di(ω-hydro-tetradecafluorooctanoyl) peroxide, di(ω-hydro-hexadecafluorononanoyl) peroxide, di(perfluorobutyryl) peroxide, di(perfluorovaleryl) peroxide, di(perfluorohexanoyl) peroxide, di(perfluoroheptanoyl) peroxide, di(perfluorooctanoyl) peroxide, di(perfluorononanoyl) peroxide, di(ω-chloro Representative examples include di[perfluoro(or fluorochloro)acyl]peroxides such as di(ω-hexafluorobutyryl)peroxide, di(ω-chloro-decafluorohexanoyl)peroxide, di(ω-chloro-tetradecafluorooctanoyl)peroxide, ω-hydro-dodecafluoroheptanoyl-ω-hydrohexadecafluorononanoyl-peroxide, ω-chloro-hexafluorobutyryl-ω-chloro-decafluorohexanoyl-peroxide, ω-hydrododecafluoroheptanoyl-perfluorobutyryl-peroxide, di(dichloropentafluorobutanoyl)peroxide, di(trichlorooctafluorohexanoyl)peroxide, di(tetrachloroundecafluorooctanoyl)peroxide, di(pentachlorotetradecafluorodecanoyl)peroxide, and di(undecachlorodotriacontafluorodocosanoyl)peroxide.

[0549] Examples of the azo compound include azodicarboxylate, azodicarboxyldiamide, 2,2'-azobisisobutyronitrile, 2,2'-azobis2,4-dimethylvaleronitrile, 2,2'-azobis(2-methylpropionamidine) dihydrochloride, and 4,4'-azobis(4-cyanovaleric acid).

[0550] The water-soluble radical polymerization initiator may be a known water-soluble peroxide, such as ammonium salts, potassium salts, or sodium salts of persulfuric acid, perborate, perchloric acid, perphosphoric acid, or percarbonate; organic peroxides such as disuccinic acid peroxide or diglutaric acid peroxide; t-butyl permaleate; or t-butyl hydroperoxide. A reducing agent such as a sulfite may also be contained, and the amount used may be 0.1 to 20 times the amount of the peroxide.

[0551] As the water-soluble peroxide, a salt of persulfate is preferred because the amount of radicals generated can be easily adjusted. Potassium persulfate (K2S2O8), ammonium persulfate ((NH4)2S2O8), and sodium persulfate (Na2S2O8) are preferred, and ammonium persulfate is most preferred.

[0552] When polymerization is carried out using a water-soluble peroxide at a polymerization temperature of 45° C. or higher, it is preferable to carry out the polymerization without using a reducing agent.

[0553] For example, when polymerization is carried out at a low temperature of 60° C. or less, it is preferable to use a redox initiator that combines an oxidizing agent and a reducing agent as the polymerization initiator. That is, it is preferable to carry out the polymerization in the presence of a redox initiator.

[0554] Examples of oxidizing agents include persulfates, organic peroxides, potassium permanganate, manganese triacetate, cerium ammonium nitrate, and bromates. Examples of reducing agents include sulfites, bisulfites, bromates, diimines, oxalic acid, and metal sulfinates. Examples of persulfates include ammonium persulfate, potassium persulfate, and sodium persulfate. Examples of sulfites include sodium sulfite and ammonium sulfite. To increase the decomposition rate of the initiator, it is also preferable to add a copper salt or an iron salt to the redox initiator combination. Examples of copper salts include copper(II) sulfate, and examples of iron salts include iron(II) sulfate. When using copper salts or iron salts, it is particularly preferable to add a chelating agent. A preferred chelating agent is ethylenediaminetetraacetic acid disodium salt dihydrate.

[0555] Examples of redox initiators include potassium permanganate / oxalic acid, ammonium persulfate / bisulfite / iron(II) sulfate, ammonium persulfate / sulfite / iron(II) sulfate, ammonium persulfate / sulfite, ammonium persulfate / iron(II) sulfate, manganese triacetate / oxalic acid, cerium ammonium nitrate / oxalic acid, bromate / sulfite, bromate / bisulfite, ammonium persulfate / sodium hydroxymethanesulfinate dihydrate, and the like, with ammonium persulfate / sodium hydroxymethanesulfinate dihydrate being preferred.

[0556] When a redox initiator is used, either the oxidizing agent or the reducing agent may be charged into a polymerization vessel in advance, and then the other may be added continuously or intermittently to initiate polymerization. For example, when ammonium persulfate / sodium hydroxymethanesulfinate dihydrate is used, it is preferred to charge ammonium persulfate into a polymerization vessel and then continuously add sodium hydroxymethanesulfinate dihydrate thereto.

[0557] The amount of persulfate used in the redox initiator is preferably 0.001 to 2.0 mass %, more preferably 0.01 to 1.5 mass %, and particularly preferably 0.05 to 1.0 mass %, relative to the aqueous medium used for polymerization.

[0558] The amount of the reducing agent used is preferably from 0.01 to 30% by mass, more preferably from 0.05 to 10% by mass, and particularly preferably from 0.1 to 5% by mass, relative to the aqueous medium used in the polymerization.

[0559] The amount of the third component (such as the copper salt or iron salt) used is preferably 0.001 to 0.5 mass %, more preferably 0.005 to 0.4 mass %, and particularly preferably 0.01 to 0.3 mass %, relative to the aqueous medium used for polymerization.

[0560] In the production method of the present disclosure, the fluorine-containing monomer may be polymerized in the presence of a chain transfer agent. Known chain transfer agents can be used, such as hydrocarbons, esters, ethers, alcohols, ketones, halogen-containing compounds, and carbonates. Among these, isopentane, diethyl malonate, and ethyl acetate are preferred because they are less likely to reduce the reaction rate, and diiodine compounds such as I(CF2)4I, I(CF2)6I, and ICH2I are preferred because they can iodine the polymer terminals and can be used as reactive polymers.

[0561] As the chain transfer agent, it is particularly preferable to use a bromine compound or an iodine compound. Examples of polymerization methods using a bromine compound or an iodine compound include iodine transfer polymerization and bromine transfer polymerization.

[0562] Iodine compounds and bromine compounds are water-insoluble and difficult to emulsify. Therefore, emulsion polymerization has traditionally been limited, and has tended to require the use of large amounts of surfactants. The production method of the present disclosure makes it possible to obtain a fluorine-containing elastomer by polymerization using an iodine compound or a bromine compound, for example, iodine transfer polymerization or bromine transfer polymerization, even in the absence of conventionally used surfactants.

[0563] Iodine transfer polymerization is a method that utilizes living radical polymerization by a radical chain reactivation mechanism, which occurs due to the low dissociation energy of carbon-iodine bonds, which are radically active and involve chain transfer reactions during the radical polymerization reaction. Known reaction conditions can be used as appropriate and are not particularly limited. For example, conditions described in "Kobunshi Ronbunshu, Vol. 49, No. 10, pp. 765-783, October 1992" and JP-A-53-3495 can be appropriately adopted. Similar polymerizations can also be performed using bromine compounds instead of iodine compounds; in the present disclosure, such polymerizations are referred to as bromine transfer polymerization.

[0564] Among these, iodine transfer polymerization is preferred from the viewpoints of polymerization reactivity and crosslinking reactivity.

[0565] Representative examples of bromine compounds or iodine compounds include, for example, compounds represented by the general formula: R 8 I x Br y (wherein x and y are each an integer of 0 to 2 and satisfy 1≦x+y≦2; R 8 is a saturated or unsaturated fluorohydrocarbon group or chlorofluorohydrocarbon group having 1 to 16 carbon atoms, or a hydrocarbon group having 1 to 3 carbon atoms, which may contain an oxygen atom). By using a bromine compound or an iodine compound, iodine or bromine is introduced into the polymer and functions as a crosslinking point.

[0566] Examples of bromine compounds and iodine compounds include 1,3-diiodoperfluoropropane, 2-iodoperfluoropropane, 1,3-diiodo-2-chloroperfluoropropane, 1,4-diiodoperfluorobutane, 1,5-diiodo-2,4-dichloroperfluoropentane, 1,6-diiodoperfluorohexane, 1,8-diiodoperfluorooctane, 1,12-diiodoperfluorododecane, 1,16-diiodoperfluorohexadecane, diiodomethane, 1,2-diiodoethane, 1,3-diiodo-n-propane, CF2Br2, BrCF2CF2Br, CF3CFBrCF2Br, CFClBr2, BrCF2 Examples include CFClBr, CFBrClCFClBr, BrCFCFCFBr, BrCFCFBrOCF, 1-bromo-2-iodoperfluoroethane, 1-bromo-3-iodoperfluoropropane, 1-bromo-4-iodoperfluorobutane, 2-bromo-3-iodoperfluorobutane, 3-bromo-4-iodoperfluorobutene-1, 2-bromo-4-iodoperfluorobutene-1, monoiodomonobromo-substituted benzene, diiodomonobromo-substituted benzene, and (2-iodoethyl) and (2-bromoethyl) substituted benzenes. These compounds may be used alone or in combination with each other. Among these, compounds containing only iodine and no bromine are preferred from the viewpoints of polymerization reactivity, crosslinking reactivity, availability, etc., and it is preferable to use 1,4-diiodoperfluorobutane, 1,6-diiodoperfluorohexane, or 2-iodoperfluoropropane.

[0567] The amount of the chain transfer agent is preferably 0.2×10 based on the total amount of monomers used in the polymerization. -3 % by mole or less, and more preferably 1.0 × 10 -3 It is up to 1 mol%.

[0568] The aqueous medium refers to a liquid containing water. The aqueous medium is not particularly limited as long as it contains water, and may contain water and, for example, a fluorine-free organic solvent such as an alcohol, ether, or ketone, and / or a fluorine-containing organic solvent having a boiling point of 40°C or lower.

[0569] In the polymerization of the fluorine-containing monomer, a pH adjuster such as a phosphate, sodium hydroxide, potassium hydroxide, or aqueous ammonia may be used.

[0570] The aqueous medium is preferably acidic. By polymerizing the fluorine-containing monomer in the presence of compound (A) and polymer (I) using an acidic aqueous medium, adhesion of the fluorine-containing polymer to the polymerization vessel can be further suppressed. The pH of the aqueous medium is preferably 7 or less, more preferably 6 or less, and preferably 3 or more.

[0571] In the production method of the present disclosure, the fluorine-containing monomer may be polymerized in the presence or absence of fluorine-containing monomer polymerization seed particles.

[0572] The "fluorine-containing monomer polymerization seed particles" are obtained by polymerizing a fluorine-containing monomer in an aqueous medium, and are present during a second polymerization in which the types and proportions of components such as monomers and additives (e.g., polymerization initiators) constituting the polymerization reaction system, as well as the reaction conditions, are different. The fluorine-containing monomer polymerization seed particles act as so-called seed particles during the polymerization of the fluorine-containing monomer, and constitute the polymerization of the fluorine-containing monomer in the presence of the seed particles, i.e., so-called seed polymerization. In the production method of the present disclosure, such seed polymerization may not be carried out when polymerizing the fluorine-containing monomer.

[0573] In the production method of the present disclosure, the polymerization temperature for polymerizing the fluorine-containing monomer is preferably 10 to 120° C., more preferably 20 to 100° C. From the viewpoints of stability of the aqueous dispersion and reduction in adhesion rate, the polymerization temperature is preferably 15 to 60° C., more preferably 18 to 55° C., and even more preferably 20 to 50° C. The polymerization temperature is preferably 60 to 120° C., more preferably 60 to 100° C., and even more preferably 70 to 90° C., since the polymerization rate is high and a fluorine-containing elastomer that gives a molded article having excellent physical properties can be obtained.

[0574] In the production method of the present disclosure, the polymerization pressure for polymerizing the fluorine-containing monomer is preferably 0.5 to 10 MPaG, more preferably 1 to 7 MPaG.

[0575] The production method of the present disclosure polymerizes a fluorine-containing monomer in the presence of compound (A), polymer (I), and an aqueous medium, and therefore can suppress adhesion of the polymer (fluorine-containing elastomer) to a polymerization vessel. The rate of polymer adhesion to the polymerization vessel is preferably 8% by mass or less, more preferably 4% by mass or less, even more preferably 3% by mass or less, and most preferably 2% by mass or less.

[0576] The polymer adhesion rate is the ratio of the mass of polymer adhesions that have adhered to the polymerization vessel after the completion of polymerization to the total amount of polymer (fluoroelastomer) after the completion of polymerization (adhesion rate to the polymerization vessel). The polymer adhesions include polymer that adheres to the inside of the polymerization vessel, such as the inner wall of the polymerization vessel and the stirring blades, after the aqueous dispersion is removed from the polymerization vessel after the completion of polymerization, and polymer that has been released from the aqueous dispersion by coagulation and is floating or settling without being dispersed in the aqueous dispersion. The mass of the polymer adhesions is the mass after the water contained in the polymer adhesions has been removed by drying at 120°C. Polymer adhesion rate (mass%) = mass of polymer adhesion / mass of obtained polymer (including adhesion) × 100 Mass of obtained polymer = mass of aqueous dispersion x solids concentration of aqueous dispersion (mass%) / 100 + mass of polymer deposit

[0577] In the production method of the present disclosure, an aqueous dispersion of a fluorine-containing elastomer is obtained by polymerizing a fluorine-containing monomer. The fluorine-containing monomer is preferably a fluorine-containing monomer (excluding compound (A)), and more preferably does not contain a hydrophilic group.

[0578] Examples of fluorine-containing monomers include vinylidene fluoride (VdF), tetrafluoroethylene (TFE), hexafluoropropylene (HFP), perfluoro(alkyl vinyl ether) (PAVE), chlorotrifluoroethylene (CTFE), trifluoroethylene, trifluoropropylene, tetrafluoropropylene, pentafluoropropylene, trifluorobutene, tetrafluoroisobutene, hexafluoroisobutene, vinyl fluoride, iodine-containing fluorinated vinyl ethers, and fluorinated vinyl ethers represented by the general formula (2): CHX 1 =CX 2 Rf (2) (In the formula, X 1 and X 2 and Rf are each a straight-chain or branched fluoroalkyl group having 1 to 12 carbon atoms.

[0579] As the PAVE, perfluoro(methyl vinyl ether) (PMVE), perfluoro(ethyl vinyl ether) (PEVE), and perfluoro(propyl vinyl ether) (PPVE) are more preferred, and PMVE is particularly preferred.

[0580] Also, PAVE has the formula: CF2 = CFOCF2ORf c (In the formula, Rf cIt is also possible to use perfluorovinyl ethers represented by the formula (wherein CF2=CFOCF2OCF3, CF2=CFOCF2OCF2CF3, or CF2=CFOCF2OCF2CF2OCF3 is a linear or branched perfluoroalkyl group having 1 to 6 carbon atoms, a cyclic perfluoroalkyl group having 5 to 6 carbon atoms, or a linear or branched perfluorooxyalkyl group having 2 to 6 carbon atoms and containing 1 to 3 oxygen atoms).Preferred examples of PAVE include CF2=CFOCF2OCF3, CF2=CFOCF2OCF2CF2OCF3, and CF2=CFOCF2OCF2CF2OCF3.

[0581] As the fluorine-containing monomer (2), a monomer in which Rf is a linear fluoroalkyl group is preferred, and a monomer in which Rf is a linear perfluoroalkyl group is more preferred. Rf preferably has 1 to 6 carbon atoms.

[0582] Examples of the fluorine-containing monomer (2) include CH2=CFCF3, CH2=CFCF2CF3, CH2=CFCF2CF2CF3, CH2=CFCF2CF2CF2CF3, CHF=CHCF3 (1,3,3,3-tetrafluoropropene), CHF=CHCF3 (E-isomer), and CHF=CHCF3 (Z-isomer), and among these, 2,3,3,3-tetrafluoropropylene represented by CH2=CFCF3 is preferred.

[0583] In the production method of the present disclosure, it is preferable to polymerize at least vinylidene fluoride or tetrafluoroethylene as the fluorine-containing monomer, and it is more preferable to polymerize vinylidene fluoride, since this can further suppress adhesion of the fluorine-containing elastomer to the polymerization vessel.

[0584] In the production method of the present disclosure, a fluorine-free monomer may be polymerized together with the fluorine-containing monomer. Examples of the fluorine-free monomer include α-olefin monomers having 2 to 10 carbon atoms, such as ethylene, propylene, butene, and pentene; and alkyl vinyl ethers in which the alkyl group has 1 to 20 carbon atoms, such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, cyclohexyl vinyl ether, hydroxybutyl vinyl ether, and butyl vinyl ether. These monomers and compounds may be used alone or in combination of two or more.

[0585] According to the production method of the present disclosure, an aqueous dispersion containing a fluorine-containing elastomer (excluding polymer (I)) can be produced. The fluorine-containing elastomer obtained by the production method of the present disclosure contains a methylene group (-CH2-) in the main chain. The fluorine-containing elastomer containing -CH2- in the main chain is not particularly limited as long as it contains a chemical structure represented by -CH2-, and examples thereof include fluorine-containing elastomers containing structures such as -CH2-CF2-, -CH2-CH(CH3)-, -CH2-CH2-, and -CH2-CF2-(CF3)-. These can be introduced into the main chain of the fluorine-containing elastomer by polymerizing, for example, vinylidene fluoride, propylene, ethylene, 2,3,3,3-tetrafluoropropylene, etc. The content of tetrafluoroethylene units in the fluorine-containing elastomer (the content of monomer units based on tetrafluoroethylene relative to the total monomer units of the fluorine-containing elastomer) may be less than 40 mol%.

[0586] As the fluorine-containing elastomer, a partially fluorinated elastomer is preferred because it can generate a larger number of fluorine-containing elastomer particles and can further suppress adhesion of the fluorine-containing elastomer to the polymerization vessel. The partially fluorinated elastomer is a fluoropolymer containing fluorine-containing monomer units, in which the content of perfluoromonomer units relative to all monomer units is less than 90 mol%, and which has a glass transition temperature of 20°C or lower and a melting peak (ΔH) magnitude of 4.5 J / g or lower.

[0587] Examples of fluorine-containing elastomers include tetrafluoroethylene (TFE), vinylidene fluoride (VdF), and fluororesin having the general formula: CF2=CF-Rf a (In the formula, Rf a -CF3 or -ORf b (Rf b It is preferable that the fluorine-containing elastomer contains a monomer unit based on at least one monomer selected from the group consisting of perfluoroethylenically unsaturated compounds represented by the formula (C1-C5 perfluoroalkyl group) (for example, hexafluoropropylene (HFP), perfluoro(alkyl vinyl ether) (PAVE)). Among these, the fluorine-containing elastomer preferably contains a VdF unit or a TFE unit, and more preferably a VDF unit.

[0588] More specific examples of the fluorine-containing elastomer include VdF-based fluorine-containing elastomers, TFE / propylene (Pr)-based fluorine-containing elastomers, TFE / Pr / VdF-based fluorine-containing elastomers, ethylene (Et) / HFP-based fluorine-containing elastomers, Et / HFP / VdF-based fluorine-containing elastomers, Et / HFP / TFE-based fluorine-containing elastomers, Et / TFE / PAVE-based fluorine-containing elastomers, etc. Among these, VdF-based fluorine-containing elastomers, TFE / Pr-based fluorine-containing elastomers, TFE / Pr / VdF-based fluorine-containing elastomers and Et / TFE / PAVE-based fluorine-containing elastomers are more preferred in terms of good heat aging resistance and oil resistance.

[0589] The VdF-based fluorine-containing elastomer is a fluorine-containing elastomer having VdF units. The content of VdF units in the fluorine-containing elastomer is preferably 20 mol% or more, more preferably 40 mol% or more, even more preferably 50 mol% or more, and particularly preferably 60 mol% or more, based on the total number of moles of VdF units and monomer units based on other monomers. In the VdF-based fluorine-containing elastomer, the VdF units preferably account for 20 mol% or more and 90 mol% or less, more preferably 40 mol% or more and 85 mol% or less, even more preferably 45 mol% or more and 80 mol% or less, and particularly preferably 50 mol% or more and 80 mol% or less, of the total number of moles of VdF units and monomer units based on other monomers.

[0590] The other monomer in the VdF-based fluorine-containing elastomer is not particularly limited as long as it is a monomer copolymerizable with VdF, and for example, the above-mentioned fluorine-containing monomers can be used.

[0591] The VdF-based fluorine-containing elastomer is preferably at least one copolymer selected from the group consisting of VdF / HFP copolymer, VdF / TFE / HFP copolymer, VdF / CTFE copolymer, VdF / CTFE / TFE copolymer, VdF / PAVE copolymer, VdF / TFE / PAVE copolymer, VdF / HFP / PAVE copolymer, VdF / HFP / TFE / PAVE copolymer, VdF / TFE / Pr copolymer, VdF / Et / HFP copolymer, and copolymer of VdF / fluorine-containing monomer (2). Furthermore, it is more preferable that the other monomer besides VdF is at least one monomer selected from the group consisting of TFE, HFP, and PAVE.

[0592] Of these, the VdF-based fluorine-containing elastomer is preferably at least one copolymer selected from the group consisting of VdF / HFP copolymer, VdF / TFE / HFP copolymer, VdF / fluorine-containing monomer (2) copolymer, VdF / PAVE copolymer, VdF / TFE / PAVE copolymer, VdF / HFP / PAVE copolymer and VdF / HFP / TFE / PAVE copolymer, and more preferably at least one copolymer selected from the group consisting of VdF / HFP copolymer, VdF / HFP / TFE copolymer, VdF / fluorine-containing monomer (2) copolymer and VdF / PAVE copolymer.

[0593] The VdF / PAVE copolymer preferably has a VdF / PAVE composition of (65 to 90) / (35 to 10) (mol %). In addition, one of the preferred embodiments is that the VdF / PAVE composition is (50 to 78) / (50 to 22) (mol %).

[0594] The VdF / TFE / PAVE copolymer preferably has a VdF / TFE / PAVE composition of (40 to 80) / (3 to 40) / (15 to 35) (mol %).

[0595] The VdF / HFP / PAVE copolymer preferably has a VdF / HFP / PAVE composition of (65 to 90) / (3 to 25) / (3 to 25) (mol %).

[0596] The VdF / HFP / TFE / PAVE copolymer preferably has a VdF / HFP / TFE / PAVE composition of (40-90) / (0-25) / (0-40) / (3-35) (mol %), and more preferably (40-80) / (3-25) / (3-40) / (3-25) (mol %).

[0597] The VdF / fluorine-containing monomer (2) copolymer preferably has a VdF / fluorine-containing monomer (2) unit ratio of (85-20) / (15-80) (mol %) and monomer units other than VdF and fluorine-containing monomer (2) accounting for 0-50 mol % of the total monomer units, and more preferably has a VdF / fluorine-containing monomer (2) unit molar ratio of (80-20) / (20-80). Another preferred embodiment has a VdF / fluorine-containing monomer (2) unit ratio of (78-50) / (22-50) (mol %).

[0598] Also preferred is a copolymer of VdF / fluorine-containing monomer (2) in which the VdF / fluorine-containing monomer (2) unit ratio is (85-50) / (15-50) (mol %) and the other monomer units other than VdF and fluorine-containing monomer (2) account for 1-50 mol % of all monomer units. Preferred monomers other than VdF and fluorine-containing monomer (2) are TFE, HFP, PMVE, perfluoroethyl vinyl ether (PEVE), PPVE, CTFE, trifluoroethylene, hexafluoroisobutene, vinyl fluoride, Et, Pr, alkyl vinyl ethers, and monomers that provide crosslinkable groups, which are given as examples of other monomers in VdF-based fluorine-containing elastomers, with PMVE, CTFE, HFP, and TFE being more preferred.

[0599] The TFE / Pr-based fluorine-containing elastomer refers to a fluorine-containing copolymer consisting of 45 to 70 mol % of TFE and 55 to 30 mol % of Pr, which may contain a specific third component in addition to these two components.

[0600] The specific third component may include, for example, fluorine-containing monomers such as fluorine-containing olefins other than TFE (e.g., VdF, HFP, CTFE, perfluoro(butyl ethylene), etc.), fluorine-containing vinyl ethers (perfluoro(propyl vinyl ether), perfluoro(methyl vinyl ether), etc.), hydrocarbon monomers such as α-olefins (ethylene, 1-butene, etc.), vinyl ethers (ethyl vinyl ether, butyl vinyl ether, hydroxybutyl vinyl ether, etc.), vinyl esters (vinyl acetate, vinyl benzoate, vinyl crotonate, vinyl methacrylate, etc.), etc. The specific third component may be used alone or in combination of two or more.

[0601] The TFE / Pr-based fluorine-containing elastomer preferably contains VdF, and among TFE / Pr-based fluorine-containing elastomers, an elastomer consisting of TFE, Pr and VdF is called a TFE / Pr / VdF-based fluorine-containing elastomer.

[0602] The TFE / Pr / VdF fluorine-containing elastomer may further contain the above-mentioned specific third component other than VdF. The above-mentioned specific third component may be used alone or in combination of two or more. The total content of the third components in the TFE / Pr fluorine-containing elastomer is preferably 35 mol% or less, more preferably 33 mol% or less, and even more preferably 31 mol% or less.

[0603] The Et / HFP copolymer preferably has an Et / HFP composition of (35 to 80) / (65 to 20) (mol %), more preferably (40 to 75) / (60 to 25) (mol %).

[0604] The Et / HFP / TFE copolymer preferably has an Et / HFP / TFE composition of (35-75) / (25-50) / (0-15) (mol %), more preferably (45-75) / (25-45) / (0-10) (mol %).

[0605] The Et / TFE / PAVE copolymer preferably has a composition of Et / TFE / PAVE of (10-40) / (32-60) / (20-40) (mol%), more preferably (20-40) / (40-50) / (20-30) (mol%). PMVE is preferred as PAVE.

[0606] The fluorine-containing elastomer is preferably a fluorine-containing elastomer containing a VdF unit, more preferably a VdF / HFP copolymer or a VdF / HFP / TFE copolymer, and particularly preferably a VdF / HFP / TFE copolymer having a composition of (32-85) / (10-34) / (0-40) (mol%). The VdF / HFP / TFE composition is more preferably (32-85) / (15-34) / (0-34) (mol%), and even more preferably (47-81) / (17-32) / (0-26) (mol%).

[0607] For example, in the above VdF / HFP copolymer, the VdF / HFP composition is preferably (45-85) / (15-55) (mol%), more preferably (50-83) / (17-50) (mol%), still more preferably (55-81) / (19-45) (mol%), and particularly preferably (60-80) / (20-40) (mol%).

[0608] The above-mentioned structure is that of the main monomer of the fluorine-containing elastomer, and in addition to the main monomer, a monomer that provides a crosslinkable group may be copolymerized. The monomer that provides a crosslinkable group may be any monomer that can introduce an appropriate crosslinkable group into the fluorine-containing elastomer depending on the production method and crosslinking system, and examples thereof include known polymerizable compounds containing a crosslinkable group such as an iodine atom, a bromine atom, a carbon-carbon double bond, a cyano group, a carboxyl group, a hydroxyl group, an amino group, or an ester group.

[0609] Preferred examples of the monomer that provides a crosslinkable group include those represented by the general formula (3): CY 1 2=CY 2 R f 2 X 1 (3) (In the formula, Y1 , Y 2 is a fluorine atom, a hydrogen atom, or -CH3; R f 2 is a linear or branched fluorine-containing alkylene group in which some or all of the hydrogen atoms have been substituted with fluorine atoms, which may have one or more ether-bonded oxygen atoms and which may have an aromatic ring; X 1 is an iodine or bromine atom) Examples of compounds include those represented by the following formula:

[0610] Specific examples of the monomer that provides a crosslinkable group include those represented by the general formula (4): CY 1 2=CY 2 R f 3 CHR 1 -X 1 (4) (In the formula, Y 1 , Y 2 , X 1 is the same as above, and R f 3 is a linear or branched fluorine-containing alkylene group which may have one or more ether-bonded oxygen atoms and in which some or all of the hydrogen atoms have been substituted with fluorine atoms, i.e., a linear or branched fluorine-containing alkylene group in which some or all of the hydrogen atoms have been substituted with fluorine atoms, a linear or branched fluorine-containing oxyalkylene group in which some or all of the hydrogen atoms have been substituted with fluorine atoms, or a linear or branched fluorine-containing polyoxyalkylene group in which some or all of the hydrogen atoms have been substituted with fluorine atoms; R 1 is a hydrogen atom or a methyl group) Iodine- or bromine-containing monomers represented by the general formulas (5) to (22): CY 4 2=CY 4 (CF2) n -X 1 (5) (In the formula, Y 4 are the same or different and are hydrogen atoms or fluorine atoms, and n is an integer of 1 to 8. CF2=CFCF2R f 4 -X 1 (6) (In the formula, R 4 is -(OCF2) n -or-(OCF(CF3)) n -, where n is an integer from 0 to 5. CF2=CFCF2(OCF(CF3)CF2) m (OCH2CF2CF2) n OCH2CF2-X 1 (7) (wherein m is an integer of 0 to 5, and n is an integer of 0 to 5) CF2=CFCF2(OCH2CF2CF2) m (OCF(CF3)CF2) n OCF(CF3)-X 1 (8) (wherein m is an integer of 0 to 5, and n is an integer of 0 to 5) CF2=CF(OCF2CF(CF3)) m O(CF2) n -X 1 (9) (wherein m is an integer of 0 to 5, and n is an integer of 1 to 8) CF2=CF(OCF2CF(CF3)) m -X 1 (10) (wherein m is an integer of 1 to 5) CF2=CFOCF2(CF(CF3)OCF2) n CF(-X 1 )CF3(11) (wherein n is an integer of 1 to 4) CF2=CFO(CF2) n OCF(CF3)-X 1 (12) (wherein n is an integer of 2 to 5) CF2=CFO(CF2) n -(C6H4)-X 1 (13) (wherein n is an integer of 1 to 6) CF2=CF(OCF2CF(CF3)) n OCF2CF(CF3)-X 1 (14) (wherein n is an integer of 1 to 2) CH2=CFCF2O(CF(CF3)CF2O) nCF(CF3)-X 1 (15) (wherein n is an integer of 0 to 5), CF2=CFO(CF2CF(CF3)O) m (CF2) n -X 1 (16) (wherein m is an integer of 0 to 5, and n is an integer of 1 to 3) CH2=CFCF2OCF(CF3)OCF(CF3)-X 1 (17) CH2=CFCF2OCH2CF2-X 1 (18) CF2=CFO(CF2CF(CF3)O) m CF2CF(CF3)-X 1 (19) (wherein m is an integer of 0 or more) CF2=CFOCF(CF3)CF2O(CF2) n -X 1 (20) (wherein n is an integer of 1 or more) CF2=CFOCF2OCF2CF(CF3)OCF2-X 1 (twenty one) CH2=CH-(CF2) n X 1 (twenty two) (wherein n is an integer of 2 to 8) (In general formulas (5) to (22), X 1 is the same as above) These may be used alone or in any combination.

[0611] The iodine- or bromine-containing monomer represented by the general formula (4) includes a monomer represented by the general formula (23): [ka] (wherein m is an integer of 1 to 5, and n is an integer of 0 to 3) Preferred examples thereof include iodine-containing fluorinated vinyl ethers represented by the following formula: [ka] Among these, ICH2CF2CF2OCF=CF2 is preferred.

[0612] More specifically, preferred examples of the iodine- or bromine-containing monomer represented by the general formula (5) include ICF2CF2CF=CH2 and I(CF2CF2)2CF=CH2.

[0613] A more specific example of the iodine- or bromine-containing monomer represented by the general formula (9) is I(CF2CF2)2OCF=CF2.

[0614] More specifically, preferred examples of the iodine- or bromine-containing monomer represented by the general formula (22) include CH2=CHCF2CF2I and I(CF2CF2)2CH=CH2.

[0615] Also, the formula: R 2 R 3 C=CR 4 -Z-CR 5 =CR 6 R 7 (In the formula, R 2 , R 3 , R 4 , R 5 , R 6 and R 7 and Z are the same or different and are both H or an alkyl group having 1 to 5 carbon atoms; Z is a linear or branched alkylene or cycloalkylene group having 1 to 18 carbon atoms, which may contain an oxygen atom and is preferably at least partially fluorinated, or a (per)fluoropolyoxyalkylene group. In the present disclosure, the term "(per)fluoropolyoxyalkylene group" means a "fluoropolyoxyalkylene group or a perfluoropolyoxyalkylene group."

[0616] Z is preferably a (per)fluoroalkylene group having 4 to 12 carbon atoms, and R 2 , R 3 , R4 , R 5 , R 6 and R 7 is preferably a hydrogen atom.

[0617] When Z is a (per)fluoropolyoxyalkylene group, it is represented by the formula: -(Q) p -CF2O-(CF2CF2O) m -(CF2O) n -CF2-(Q) p - (wherein Q is an alkylene group having 1 to 10 carbon atoms or an oxyalkylene group having 2 to 10 carbon atoms, p is 0 or 1, and m and n are integers such that the m / n ratio is 0.2 to 5 and the molecular weight of the (per)fluoropolyoxyalkylene group is 500 to 10,000, preferably 1,000 to 4,000.) In this formula, Q is preferably -CHOCH- and -CHO(CHCHO) s Selected from CH2-(s=1~3).

[0618] Preferred bisolefins are CH2=CH-(CF2)2-CH=CH2, CH2=CH-(CF2)4-CH=CH2, CH2=CH-(CF2)6-CH=CH2, Formula: CH2=CH-Z 1 -CH=CH2 (In the formula, Z 1 is -CH2OCH2-CF2O-(CF2CF2O) m -(CF2O) n -CF2-CH2OCH2- (m / n is 0.5, molecular weight is preferably 2000) Examples include:

[0619] Among these, 3,3,4,4,5,5,6,6,7,7,8,8-dodecafluoro-1,9-decadiene represented by CH2=CH-(CF2)6-CH=CH2 is preferred.

[0620] The number average molecular weight Mn of the fluorine-containing elastomer is preferably from 1,000 to 1,000,000, more preferably from 10,000 to 500,000, and particularly preferably from 20,000 to 300,000.

[0621] The fluorine-containing elastomer preferably has a fluorine content of 50% by mass or more, more preferably 55% by mass or more, and even more preferably 60% by mass or more. The upper limit of the fluorine content is preferably 75% by mass or less, and more preferably 73% by mass or less. The fluorine content is 19 F-NMR and 1 It is calculated based on measurements such as H-NMR and elemental analysis.

[0622] The fluorine-containing elastomer preferably has a Mooney viscosity at 100°C (ML1+10(100°C)) of 130 or less. The Mooney viscosity is more preferably 110 or less, and even more preferably 90 or less. The Mooney viscosity is more preferably 10 or more, and even more preferably 20 or more. The Mooney viscosity here is a value measured in accordance with JIS K 6300-1.2013.

[0623] The fluorine-containing elastomer preferably has a glass transition temperature of -50 to 0°C. The glass transition temperature is more preferably -2°C or lower, and even more preferably -3°C or lower. The glass transition temperature is more preferably -45°C or higher, and even more preferably -40°C or higher. The glass transition temperature may be -10°C or higher, or may be -9°C or higher. Here, the glass transition temperature can be determined from the DSC differential curve in accordance with JIS K6240:2011, using a differential scanning calorimeter (for example, X-DSC7000 manufactured by Hitachi High-Tech Science Corporation) by heating 10 mg of a sample at a rate of 20°C / min to obtain a DSC curve.

[0624] The fluorine-containing elastomer preferably has an iodine content of 0.05 to 1.0% by mass, more preferably 0.08% by mass or more, even more preferably 0.10% by mass or more, and more preferably 0.80% by mass or less, even more preferably 0.60% by mass or less.

[0625] The iodine content can be determined by elemental analysis. Specifically, 12 mg of fluorine-containing elastomer is mixed with 5 mg of Na2SO3, and 30 mg of a 1:1 mixture of Na2CO3 and K2CO3 (by mass) is dissolved in 20 ml of pure water to form an absorption solution. The mixture is burned in oxygen in a quartz flask, left for 30 minutes, and then measured using a Shimadzu 20A ion chromatograph. For the calibration curve, KI standard solutions containing 0.5 ppm by mass and 1.0 ppm by mass of iodine ions can be used.

[0626] The fluorine-containing elastomer preferably contains a -CH2I structure. 1 This can be confirmed by H-NMR spectroscopy. Fluorine-containing elastomers containing the -CH2I structure can be obtained by iodine transfer polymerization.

[0627] In the fluorine-containing elastomer, the amount of -CH2I structures relative to 100 mol% of -CH2- structures is preferably 0.05 to 1.50 mol%. The amount of -CH2I structures is more preferably 0.08 mol% or more, even more preferably 0.12 mol% or more, more preferably 1.20 mol% or less, still more preferably 1.00 mol% or less, and particularly preferably 0.80 mol% or less. The amount of -CH2I structures is 1 It can be determined by H-NMR spectroscopy.

[0628] The fluorine-containing elastomer more preferably contains a -CF2CH2I structure. A fluorine-containing elastomer containing a -CF2CH2I structure can be obtained by producing a VdF-based fluorine-containing elastomer by iodine transfer polymerization.

[0629] In the fluorine-containing elastomer, the amount of -CF2CH2I structures relative to 100 mol% of -CH2- structures is preferably 0.05 to 1.50 mol%. The amount of -CF2CH2I structures is more preferably 0.08 mol% or more, even more preferably 0.12 mol% or more, more preferably 1.20 mol% or less, even more preferably 1.00 mol% or less, and particularly preferably 0.80 mol% or less. The amount of -CF2CH2I structures is 1 In the H-NMR spectrum, A is the integral value of all peak intensities observed in the chemical shift region of 3.75 to 4.05 ppm due to -CH2I, and B is the integral value of all peak intensities observed in the chemical shift regions of 2.3 to 2.7 ppm and 2.9 to 3.75 ppm due to -CH2-. It is calculated using A / B*100.

[0630] As the fluorine-containing monomer used in the production method of the present disclosure, the fluorine-containing monomers described for the fluorine-containing elastomer can be used appropriately.

[0631] According to the production method of the present disclosure, an aqueous dispersion of a fluorine-containing elastomer can be obtained. The solids concentration (content of the fluorine-containing elastomer) of the obtained aqueous dispersion of the fluorine-containing elastomer is preferably 10 to 50 mass%, more preferably 15 to 40 mass%, and even more preferably 20 to 30 mass% at the time when the polymerization is completed.

[0632] The aqueous dispersion of a fluorine-containing elastomer may contain fluorine-containing elastomer particles. The average particle size of the fluorine-containing elastomer particles is preferably 10 to 800 nm, more preferably 50 to 500 nm, and even more preferably 70 to 300 nm. The average particle size of the fluorine-containing elastomer particles is a cumulant average diameter, and can be measured by dynamic light scattering.

[0633] The number of fluorine-containing elastomer particles contained in the aqueous dispersion of the fluorine-containing elastomer is preferably 1.0 × 10 12 particles / cc or more, more preferably 5.0 × 10 12 particles / cc or more, and more preferably 1.0 × 1013 particles / cc or more, and particularly preferably 1.2 × 10 14 particles / cc or more, most preferably 1.3 x 10 14 The number of particles (the number of polymer particles) can be calculated according to the following formula:

[0634]

number

[0635] The aqueous dispersion of the fluorine-containing elastomer may be subjected to treatment such as coagulation or heating.

[0636] The coagulation can be carried out by adding alkaline earth and earth metal salts to the aqueous dispersion, such as sulfates, nitrates, hydrochlorides, and acetates of calcium, magnesium, aluminum, and the like.

[0637] The coagulated fluorine-containing elastomer may be washed with water to remove small amounts of impurities such as buffer solutions and salts present in the fluorine-containing elastomer, and then the washed fluorine-containing elastomer may be dried at a drying temperature of preferably 40 to 200°C, more preferably 60 to 180°C, and even more preferably 80 to 150°C.

[0638] The form of the fluorine-containing elastomer obtained after coagulation is not particularly limited, and may be a gum, crumb, powder, pellet, etc., with gum or crumb being preferred. A gum is a small granular mass of a fluorine-containing elastomer, and a crumb is an amorphous mass formed when the fluorine-containing elastomer cannot maintain its granular shape as a gum at room temperature and instead fuses with other fluorine-containing elastomers. The gum or crumb is preferably obtained by coagulating, drying, etc., the aqueous dispersion obtained by the production method of the present disclosure using a conventionally known method.

[0639] Polymer (I), decomposition products and by-products of polymer (I), and residual monomers produced as by-products of polymer (I) may be recovered and purified from the wastewater generated by the coagulation or washing and / or the off-gas generated by drying, thereby reusing polymer (I), decomposition products and by-products of polymer (I), and residual monomers. The recovery and purification methods are not particularly limited, and can be carried out by known methods. For example, they can be carried out by the methods described in JP-A-2011-520020, U.S. Patent Application Publication No. 2007 / 0015937, U.S. Patent Application Publication No. 2007 / 0025902, and U.S. Patent Application Publication No. 2007 / 0027251.

[0640] Methods for recovering polymer (I), decomposition products and by-products of polymer (I) produced as by-products from polymer (I), residual monomers, etc. from the wastewater include contacting the wastewater with adsorbent particles such as ion exchange resin, activated carbon, silica gel, clay, zeolite, etc. to adsorb polymer (I), and then separating the wastewater from the adsorbent particles. Incineration of the adsorbent particles that have adsorbed polymer (I) etc. can prevent release of polymer (I), etc. into the environment.

[0641] Alternatively, polymer (I) or the like can be recovered by desorbing and eluting it from ion exchange resin particles that have adsorbed it using a known method. For example, when the ion exchange resin particles are anion exchange resin particles, polymer (I) or the like can be eluted by contacting a mineral acid with the anion exchange resin. Subsequently, when a water-soluble organic solvent is added to the resulting eluate, the mixture usually separates into two phases. The lower phase containing polymer (I) or the like can be recovered by neutralizing it. Examples of the water-soluble organic solvent include polar solvents such as alcohols, ketones, and ethers.

[0642] Other methods for recovering polymer (I) and the like from ion exchange resin particles include a method using an ammonium salt and a water-soluble organic solvent, and a method using an alcohol and, if desired, an acid. In the latter method, an ester derivative of polymer (I) and the like is produced, which can be easily separated from the alcohol by distillation.

[0643] When the wastewater contains fluorine-containing elastomer particles and other solids, it is preferable to remove them before contacting the wastewater with the adsorbent particles. Methods for removing the fluorine-containing elastomer particles and other solids include a method in which aluminum salts or the like are added to precipitate them, followed by separation of the precipitate from the wastewater, and electrocoagulation. Mechanical methods, such as crossflow filtration, depth filtration, and precoat filtration, may also be used for removal.

[0644] The concentration of the unagglomerated fluorine-containing elastomer in the wastewater is preferably low from the viewpoint of productivity, more preferably less than 0.4% by mass, particularly preferably less than 0.3% by mass.

[0645] One method for recovering the polymer (I) and the like from the off-gas is to use a scrubber to contact the off-gas with deionized water, an aqueous alkali solution, an organic solvent such as a glycol ether solvent, and the like to obtain a scrubber solution containing the polymer (I) and the like. When a highly concentrated aqueous alkali solution is used as the aqueous alkali solution, the scrubber solution can be recovered in a state in which the polymer (I) and the like are phase-separated, making it easy to recover and reuse the polymer (I) and the like. Examples of alkaline compounds include alkali metal hydroxides and quaternary ammonium salts.

[0646] The scrubber solution containing the polymer (I) and the like may be concentrated using a reverse osmosis membrane or the like. The concentrated scrubber solution usually contains fluoride ions, but by adding alumina after concentration to remove the fluoride ions, it is possible to facilitate the reuse of the polymer (I) and the like. Alternatively, the scrubber solution may be brought into contact with adsorbent particles to adsorb the polymer (I) and the like, and the polymer (I) and the like may be recovered by the method described above.

[0647] The polymer (I) and the like recovered by any of the above methods can be reused for the production of a fluorine-containing elastomer.

[0648] A composition (crosslinkable composition) can be produced by adding a crosslinking agent, etc. to the aqueous dispersion of a fluorine-containing elastomer or the fluorine-containing elastomer obtained by the production method of the present disclosure. The type and amount of the crosslinking agent are not particularly limited, and any crosslinking agent can be used within known ranges.

[0649] When the fluorine-containing elastomer is an uncrosslinked elastomer, the crosslinking system thereof may be, for example, a peroxide crosslinking system, a polyol crosslinking system, a polyamine crosslinking system, etc., and is preferably at least one selected from the group consisting of a peroxide crosslinking system and a polyol crosslinking system. From the viewpoint of chemical resistance, a peroxide crosslinking system is preferred, and from the viewpoint of heat resistance, a polyol crosslinking system is preferred.

[0650] Therefore, the crosslinking agent is preferably at least one crosslinking agent selected from the group consisting of polyol crosslinking agents and peroxide crosslinking agents, and more preferably a peroxide crosslinking agent.

[0651] The amount of the crosslinking agent to be added may be appropriately selected depending on the type of crosslinking agent, etc., but is preferably 0.2 to 6.0 parts by mass, more preferably 0.3 to 5.0 parts by mass, per 100 parts by mass of the fluorine-containing elastomer.

[0652] Peroxide crosslinking can be carried out by using a peroxide-crosslinkable uncrosslinked elastomer as the fluorine-containing elastomer and an organic peroxide as the crosslinking agent.

[0653] The peroxide-crosslinkable uncrosslinked elastomer is not particularly limited as long as it has a peroxide-crosslinkable moiety. The peroxide-crosslinkable moiety is not particularly limited, and examples thereof include a moiety having an iodine atom and a moiety having a bromine atom.

[0654] The organic peroxide may be any organic peroxide that can easily generate peroxy radicals in the presence of heat or a redox system, and examples thereof include 1,1-bis(t-butylperoxy)-3,5,5-trimethylcyclohexane, 2,5-dimethylhexane-2,5-dihydroperoxide, di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, α,α-bis(t-butylperoxy)-p-diisopropylbenzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)-hexyne-3, benzoyl peroxide, t-butylperoxybenzene, t-butylperoxymaleic acid, t-butylperoxyisopropyl carbonate, and t-butylperoxybenzoate. Among these, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane and 2,5-dimethyl-2,5-di(t-butylperoxy)-hexyne-3 are preferred.

[0655] The amount of the organic peroxide to be added is preferably 0.1 to 15 parts by mass, more preferably 0.3 to 5 parts by mass, per 100 parts by mass of the fluorine-containing elastomer.

[0656] When the crosslinking agent is an organic peroxide, the fluorine-containing elastomer composition preferably further contains a crosslinking aid. Examples of the crosslinking aid include triallyl cyanurate, triallyl isocyanurate (TAIC), triacryl formal, triallyl trimellitate, N,N'-m-phenylene bismaleimide, dipropargyl terephthalate, diallyl phthalate, tetraallyl terephthalate amide, triallyl phosphate, bismaleimide, fluorinated triallyl isocyanurate (1,3,5-tris(2,3,3-trifluoro-2-propenyl)-1,3,5-triazine-2,4,6-trimethylsilyl)propan-2-ol, and the like. Examples of suitable siloxanes include methyl acrylate, methyl acrylate (MCA), ...

[0657] The amount of cross-linking aid blended is preferably 0.01 to 10 parts by mass, more preferably 0.01 to 7.0 parts by mass, and even more preferably 0.1 to 5.0 parts by mass, per 100 parts by mass of the fluorine-containing elastomer. If the amount of cross-linking aid is less than 0.01 part by mass, the mechanical properties and flexibility tend to deteriorate. If the amount exceeds 10 parts by mass, the heat resistance tends to deteriorate and the durability of the molded product also tends to deteriorate.

[0658] Polyol crosslinking can be carried out by using a polyol-crosslinkable uncrosslinked elastomer as the fluorine-containing elastomer and a polyhydroxy compound as the crosslinking agent. The amount of the polyhydroxy compound in the polyol crosslinking system is preferably 0.01 to 10 parts by mass per 100 parts by mass of the polyol-crosslinkable uncrosslinked elastomer. By using an amount of the polyhydroxy compound in this range, polyol crosslinking can be sufficiently promoted. The amount is more preferably 0.02 to 8 parts by mass, and even more preferably 0.03 to 4 parts by mass.

[0659] The polyol-crosslinkable uncrosslinked elastomer is not particularly limited, and may be any uncrosslinked elastomer having a polyol-crosslinkable moiety. The polyol-crosslinkable moiety is not particularly limited, and examples thereof include moieties having vinylidene fluoride (VdF) units. Methods for introducing the crosslinkable moiety include copolymerizing a monomer that provides a crosslinkable moiety during polymerization of the uncrosslinked elastomer.

[0660] As the polyhydroxy compound, a polyhydroxy aromatic compound is preferably used because of its excellent heat resistance.

[0661] The polyhydroxy aromatic compound is not particularly limited, and examples thereof include 2,2-bis(4-hydroxyphenyl)propane (hereinafter referred to as bisphenol A), 2,2-bis(4-hydroxyphenyl)perfluoropropane (hereinafter referred to as bisphenol AF. Bisphenol AF is available from, for example, Fujifilm Wako Pure Chemical Industries, Ltd., Central Glass Co., Ltd., etc.), 1,3-dihydroxybenzene, 1,7-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 4,4'-dihydroxydiphenyl, 4,4'-dihydro Examples of suitable polyhydroxy aromatic compounds include hydroxystilbene, 2,6-dihydroxyanthracene, hydroquinone, catechol, 2,2-bis(4-hydroxyphenyl)butane (hereinafter referred to as bisphenol B), 4,4-bis(4-hydroxyphenyl)valeric acid, 2,2-bis(4-hydroxyphenyl)tetrafluorodichloropropane, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl ketone, tri(4-hydroxyphenyl)methane, 3,3',5,5'-tetrachlorobisphenol A, and 3,3',5,5'-tetrabromobisphenol A. These polyhydroxy aromatic compounds may be alkali metal salts or alkaline earth metal salts, but if the copolymer is coagulated using an acid, it is preferable not to use such metal salts. The amount of polyhydroxy aromatic compound to be added is 0.1 to 15 parts by weight, preferably 0.5 to 5 parts by weight, per 100 parts by weight of the uncrosslinked elastomer.

[0662] When the crosslinking agent is a polyhydroxy compound, the fluorine-containing elastomer composition preferably further contains a crosslinking accelerator, which accelerates the formation of intramolecular double bonds in the dehydrofluorination reaction of the polymer main chain and the addition of the polyhydroxy compound to the formed double bonds.

[0663] The crosslinking accelerator may be used in combination with an acid acceptor such as magnesium oxide or a crosslinking aid.

[0664] Examples of the crosslinking accelerator include onium compounds, and among the onium compounds, at least one selected from the group consisting of ammonium compounds such as quaternary ammonium salts, phosphonium compounds such as quaternary phosphonium salts, oxonium compounds, sulfonium compounds, cyclic amines, and monofunctional amine compounds is preferred, and at least one selected from the group consisting of quaternary ammonium salts and quaternary phosphonium salts is more preferred.

[0665] The quaternary ammonium salt is not particularly limited, and examples thereof include 8-methyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, 8-methyl-1,8-diazabicyclo[5,4,0]-7-undecenium iodide, 8-methyl-1,8-diazabicyclo[5,4,0]-7-undecenium hydroxide, 8-methyl-1,8-diazabicyclo[5,4,0]-7-undecenium methyl methylsulfate, 8-ethyl-1,8-diazabicyclo[5,4,0]-7-undecenium bromide, 8-propyl-1,8-diazabicyclo[5,4,0]-7-undecenium bromide, 8-dodecyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, 8-dodecyl-1,8-diazabicyclo[5,4,0]-7-undecenium hydroxide, 8-eicosyl-1,8-di Examples of the diastereoisopropyl methyl ether include azabicyclo[5,4,0]-7-undecenium chloride, 8-tetracosyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, 8-benzyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride (hereinafter referred to as DBU-B. DBU-B is available from, for example, Fujifilm Wako Pure Chemical Industries, Ltd.), 8-benzyl-1,8-diazabicyclo[5,4,0]-7-undecenium hydroxide, 8-phenethyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, 8-(3-phenylpropyl)-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, tetrabutylammonium hydrogen sulfate, tetrabutylammonium hydroxide, tetrabutylammonium chloride, and tetrabutylammonium bromide. Among these, DBU-B is preferred from the viewpoints of crosslinkability, mechanical properties, and flexibility.

[0666] Furthermore, the quaternary phosphonium salt is not particularly limited, and examples thereof include tetrabutylphosphonium chloride, benzyltriphenylphosphonium chloride (hereinafter referred to as BTPPC), benzyltrimethylphosphonium chloride, benzyltributylphosphonium chloride, tributylallylphosphonium chloride, tributyl-2-methoxypropylphosphonium chloride, and benzylphenyl(dimethylamino)phosphonium chloride. Among these, benzyltriphenylphosphonium chloride (BTPPC) is preferred from the viewpoints of crosslinkability, mechanical properties, and flexibility.

[0667] Furthermore, as the crosslinking accelerator, a solid solution of a quaternary ammonium salt and bisphenol AF, a solid solution of a quaternary phosphonium salt and bisphenol AF, or the chlorine-free crosslinking accelerator disclosed in JP-A-11-147891 can also be used.

[0668] The amount of crosslinking accelerator added is preferably 0.01 to 8.00 parts by mass, more preferably 0.02 to 5.00 parts by mass, and even more preferably 0.03 to 3.00 parts by mass, relative to 100 parts by mass of the uncrosslinked elastomer. If the amount of crosslinking accelerator is less than 0.01 part by mass, crosslinking of the uncrosslinked elastomer may not proceed sufficiently, and the heat resistance and other properties of the resulting molded article may be reduced. If the amount exceeds 8.00 parts by mass, the molding processability of the fluorine-containing elastomer composition may be reduced, and the mechanical properties of elongation and flexibility may also tend to be reduced.

[0669] The acid acceptor is used to neutralize acidic substances generated during polyol crosslinking, and specific examples include magnesium oxide, calcium hydroxide (for example, NICC5000 (manufactured by Inoue Lime Industry Co., Ltd.), CALDIC#2000, CALDIC#1000 (manufactured by Ohmi Chemical Industry Co., Ltd.)), calcium oxide, litharge (lead oxide), zinc oxide, dibasic lead phosphite, hydrotalcite, and the like, and is preferably at least one selected from the group consisting of high-activity magnesium oxide and low-activity magnesium oxide.

[0670] The polyamine crosslinking can be carried out by using a polyamine-crosslinkable fluorine-containing elastomer as the fluorine-containing elastomer and a polyamine compound as the crosslinking agent.

[0671] The polyamine-crosslinkable fluorine-containing elastomer is not particularly limited as long as it has a polyamine-crosslinkable moiety. The polyamine-crosslinkable moiety is not particularly limited, and examples thereof include a moiety having a vinylidene fluoride (VdF) unit. Methods for introducing the crosslinkable moiety include copolymerizing a monomer that provides a crosslinkable moiety during polymerization of the fluorine-containing elastomer.

[0672] Examples of polyamine compounds include hexamethylenediamine carbamate, N,N'-dicinnamylidene-1,6-hexamethylenediamine, 4,4'-bis(aminocyclohexyl)methane carbamate, etc. Among these, N,N'-dicinnamylidene-1,6-hexamethylenediamine is preferred.

[0673] The method for obtaining a composition containing a crosslinking agent is not particularly limited as long as it can uniformly mix the fluorine-containing elastomer obtained by the production method of the present disclosure with the crosslinking agent. For example, there is a method in which a powder obtained by coagulating the fluorine-containing elastomer alone is kneaded with other additives and compounding ingredients as necessary in a kneader such as an open roll.

[0674] The present disclosure also relates to a fluorine-containing elastomer (excluding polymer (I)) containing monomer units (A) derived from compound (A) which contains a methylene group in the main chain and further contains a functional group reactive by radical polymerization and a hydrophilic group, and a composition containing polymer (I) containing polymerization units (I) derived from monomer (I) represented by general formula (I). The composition of the present disclosure can be suitably produced by the production method of the present disclosure.

[0675] The form of the composition of the present disclosure is not particularly limited, and may be, for example, an aqueous dispersion, gum, crumb, powder, pellet, etc. An aqueous dispersion is a dispersion system in which an aqueous medium is the dispersion medium and a fluorine-containing elastomer is the dispersoid. The aqueous medium is not particularly limited as long as it is a liquid containing water, and may contain, in addition to water, an organic solvent such as alcohol, ether, ketone, or paraffin wax.

[0676] The preferred structure of the fluorine-containing elastomer is the same as the structure of the fluorine-containing elastomer obtained by the production method of the present disclosure.

[0677] The preferred structures of the compound (A) and the polymer (I) are the same as those of the polymer (I) used in the production method of the present disclosure.

[0678] The content of the monomer units (A) based on the compound (A) in the fluorine-containing elastomer is preferably 0.0009 to 1.5% by mass, more preferably 0.0015% by mass or more, even more preferably 0.0030% by mass or more, particularly preferably 0.0060% by mass or more, most preferably 0.0090% by mass or more, more preferably 0.30% by mass or less, even more preferably 0.15% by mass or less, particularly preferably 0.09% by mass or less, and most preferably 0.06% by mass or less, based on the total monomer units. If the content of the monomer units (A) based on the compound (A) is too high, the properties required of the fluorine-containing elastomer may be impaired.

[0679] The content of the monomer unit (A) based on the compound (A) in the fluorine-containing elastomer can be calculated by an appropriate combination of NMR, FT-IR, elemental analysis and X-ray fluorescence analysis depending on the type of monomer.

[0680] The lower limit of the content of polymer (I) in the composition is preferably 0.00001% by mass, more preferably 0.0001% by mass, still more preferably 0.001% by mass, and particularly preferably 0.01% by mass, based on the fluorine-containing elastomer. The upper limit of the content of polymer (I) in the composition is preferably 20% by mass, more preferably 10% by mass, still more preferably 6% by mass, even more preferably 4% by mass, and most preferably 2% by mass or less.

[0681] The content of polymer (I) in the composition can be determined, for example, by solid-state NMR measurement or melt NMR measurement. When polymer (I) contains a carbonyl group, it can also be determined by a Fourier transform infrared spectrometer. Methods for measuring the content of polymer (I) include those described in International Publication Nos. 2014 / 099453, 2010 / 075497, 2010 / 075496, 2011 / 008381, 2009 / 055521, 1987 / 007619, JP-A-61-293476, 2010 / 075494, 2010 / 075359, 2012 / 082454, 2006 / 119224, and 2013 / 08 The measurement methods for each polymer described in, for example, WO 2012 / 082707, WO 2012 / 082703, WO 2012 / 082451, WO 2006 / 135825, WO 2004 / 067588, WO 2009 / 068528, JP 2004-075978, JP 2001-226436, WO 1992 / 017635, WO 2014 / 069165, and JP 11-181009 are described. Specific devices that can be used include AVANCE III HD400 manufactured by Bruker and AVANCE300 manufactured by Bruker. The rotation speed is set according to the resonance frequency of the apparatus so that the spinning side bands do not overlap with the peaks used to calculate the contents of the fluorine-containing elastomer and polymer (I).

[0682] The composition of the present disclosure preferably contains substantially no fluorine-containing surfactant having substantially no functional group capable of reacting by radical polymerization.

[0683] In the present disclosure, "substantially free of fluorine-containing surfactants having no functional groups capable of reacting by radical polymerization" means that the content of fluorine-containing surfactants in the composition is 10 ppm by mass or less, preferably 1 ppm by mass or less, more preferably 100 ppb by mass or less, even more preferably 10 ppb by mass or less, still more preferably 1 ppb by mass or less, and particularly preferably below the detection limit of the fluorine-containing surfactant as measured by liquid chromatography-mass spectrometry (LC / MS).

[0684] The content of the fluorine-containing surfactant can be determined by a known method, for example, by LC / MS analysis. First, methanol is added to the composition to perform extraction, and the resulting extract is analyzed by LC / MS. To further increase the extraction efficiency, treatments such as Soxhlet extraction and ultrasonic treatment may be performed. Molecular weight information is extracted from the obtained LC / MS spectrum and confirmed to match the structural formula of the candidate fluorine-containing surfactant. Then, aqueous solutions containing five or more levels of the identified fluorine-containing surfactant are prepared, and LC / MS analysis is performed on the aqueous solutions containing each level. The relationship between the content and the area corresponding to that content is plotted, and a calibration curve is drawn. Then, using the calibration curve, the area of ​​the LC / MS chromatogram of the fluorine-containing surfactant in the extract can be converted into the content of the fluorine-containing surfactant.

[0685] The composition of the present disclosure may be an aqueous dispersion containing a fluorine-containing elastomer, polymer (I), and an aqueous medium. The upper limit of the solids concentration of the aqueous dispersion is preferably 50 mass%, more preferably 40 mass%, even more preferably 35 mass%, and particularly preferably 30 mass%, based on the aqueous dispersion. The lower limit of the solids concentration of the aqueous dispersion is preferably 5 mass%, more preferably 10 mass%, even more preferably 15 mass%, and particularly preferably 20 mass%. The solids concentration of the aqueous dispersion can be adjusted by diluting or concentrating the aqueous dispersion obtained by polymerization.

[0686] The solids concentration of the aqueous dispersion is the concentration of solids contained in the aqueous dispersion. Examples of solids include a fluorine-containing elastomer and polymer (I). The solids concentration of the aqueous dispersion may be the content of the fluorine-containing elastomer in the aqueous dispersion. The solids concentration of the aqueous dispersion can be determined by drying 1 g of the aqueous dispersion at 150°C for 180 minutes, measuring the mass of the heating residue, and calculating the ratio of the mass of the heating residue to the mass of the aqueous dispersion.

[0687] The aqueous dispersion may further contain a crosslinking agent, a filler, etc. The preferred configuration of the crosslinking agent is the same as the configuration of the composition (crosslinkable composition) obtained by the production method of the present disclosure.

[0688] The aqueous dispersion can be made into a dispersion suitable for rubber molding processing by adding a dispersion stabilizer such as a hydrocarbon surfactant, concentrating it, etc., as necessary. The dispersion is then treated by pH adjustment, coagulation, heating, etc.

[0689] The composition of the present disclosure may be a coagulate, gum, crumb, powder, pellet, or the like obtained by coagulating the fluorine-containing elastomer contained in an aqueous dispersion, and is preferably a gum or crumb. A gum is a small granular mass of a fluorine-containing elastomer, and a crumb is an amorphous mass formed when the fluorine-containing elastomer cannot maintain its small granular shape as a gum at room temperature and instead fuses with other fluorine-containing elastomers. The gum or crumb is preferably obtained by coagulating, drying, or the like from the aqueous dispersion obtained by the production method of the present disclosure using a conventionally known method.

[0690] The water content of the composition is not particularly limited, but is preferably 1% by mass or less, more preferably 0.1% by mass or less, and even more preferably 0.01% by mass or less, relative to the mass of the composition. The water content of the composition can be calculated, for example, by heating the composition to 120°C or higher to thoroughly dry it, measuring the weight of the composition before and after heating, and dividing the weight loss by the weight before heating.

[0691] The composition may contain a crosslinking agent. The preferred configuration of the crosslinking agent is the same as the configuration of the composition (crosslinkable composition) obtained by the production method of the present disclosure.

[0692] The composition may contain at least one polyfunctional compound. A polyfunctional compound is a compound having two or more functional groups of the same or different structures in one molecule. The functional group of the polyfunctional compound may be any functional group that is generally known to be reactive, such as a carbonyl group, a carboxyl group, a haloformyl group, an amide group, an olefin group, an amino group, an isocyanate group, a hydroxyl group, or an epoxy group.

[0693] The composition may contain various additives that are commonly incorporated into elastomers, such as fillers (carbon black, barium sulfate, etc.), processing aids (wax, etc.), plasticizers, colorants, stabilizers, tackifiers (coumarone resin, coumarone-indene resin, etc.), release agents, electrical conductivity imparting agents, thermal conductivity imparting agents, surface anti-tack agents, flexibility imparting agents, heat resistance improvers, and flame retardants, as well as one or more commonly used crosslinking agents and crosslinking accelerators other than those mentioned above.

[0694] The content of the filler such as carbon black is not particularly limited, but is preferably 0 to 300 parts by mass, more preferably 1 to 150 parts by mass, still more preferably 2 to 100 parts by mass, and particularly preferably 2 to 75 parts by mass, per 100 parts by mass of the fluorine-containing elastomer.

[0695] The content of processing aids such as wax is preferably 0 to 10 parts by mass, more preferably 0 to 5 parts by mass, per 100 parts by mass of the fluorine-containing elastomer. When processing aids, plasticizers or release agents are used, the mechanical properties and sealing properties of the resulting molded article tend to deteriorate, so it is necessary to adjust the contents of these agents within ranges that allow the desired properties of the resulting molded article.

[0696] A molded article can be obtained by molding the composition. Alternatively, a molded article can be obtained by molding and crosslinking the composition. The composition can be molded by a conventionally known method. The molding and crosslinking methods and conditions may be within the range of known methods and conditions for the molding and crosslinking employed. The order of molding and crosslinking is not limited, and molding may be followed by crosslinking, crosslinking may be followed by molding, or molding and crosslinking may be performed simultaneously.

[0697] Examples of molding methods include, but are not limited to, compression molding, casting, injection molding, extrusion molding, and rotocure molding. Examples of crosslinking methods that can be used include steam crosslinking, heat crosslinking, and radiation crosslinking, with steam crosslinking and heat crosslinking being preferred. Specific crosslinking conditions, which are not limited to, are typically a temperature range of 140 to 250°C, a crosslinking time of 1 minute to 24 hours, and can be determined appropriately depending on the types of crosslinking accelerator, crosslinking agent, acid acceptor, etc.

[0698] Furthermore, by heating the obtained molded article in an oven, etc., it is possible to improve the mechanical properties and the compression set characteristics at high temperatures, etc. Specific crosslinking conditions, which are not limited to any particular conditions, are usually in the temperature range of 140 to 300°C and the time range of 30 minutes to 72 hours, and may be appropriately determined depending on the types of crosslinking accelerator, crosslinking agent, acid acceptor, etc.

[0699] The obtained molded articles can be used as various parts in various fields such as the automotive industry, the aircraft industry, the semiconductor industry, etc. The molded articles can be used for applications similar to the crosslinked rubber molded articles described in JP 2013-216915 A and the fluororubber molded articles described in JP 2019-94430 A, such as sealing materials, sliding members, and non-adhesive members.

[0700] Examples of uses of the molded articles include various sealing materials and packings such as rings, packings, gaskets, diaphragms, oil seals, and bearing seals. As sealing materials, they can be used in applications requiring excellent non-stick properties and low friction. In particular, they can be suitably used as various sealing materials in the automotive industry, etc.

[0701] It can also be used as a tube, hose, roll, various rubber rolls, flexible joint, rubber plate, coating, belt, damper, valve, valve seat, valve body, chemical-resistant coating material, laminating material, lining material, etc.

[0702] Although the embodiments have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the claims. [Example]

[0703] Next, embodiments of the present disclosure will be described with reference to examples, but the present disclosure is not limited to these examples.

[0704] The values ​​in the examples were measured by the following methods.

[0705] <Oxygen concentration in the reactor> The gas coming out of the exhaust gas line of the reactor under N flow was measured and analyzed using a low-concentration oxygen analyzer (trade name "PS-820-L", manufactured by Iijima Electronics Co., Ltd.) to determine the oxygen concentration inside the reactor during polymerization.

[0706] <Polymer concentration> Approximately 1 g of the aqueous polymer solution was dried in a vacuum dryer at 60°C for 60 minutes, the mass of the heating residue was measured, and the ratio of the mass of the heating residue to the mass (1 g) of the aqueous polymer solution was expressed as a percentage.

[0707] <Method for measuring weight average molecu...

Claims

[Claim 1] A method for producing an aqueous dispersion of a fluorine-containing elastomer, comprising polymerizing a compound (A) containing a functional group reactive by radical polymerization and a hydrophilic group, a polymer (I) containing polymerization units (I) based on a monomer (I) represented by general formula (I), and a fluorine-containing monomer in the presence of an aqueous medium to produce an aqueous dispersion of a fluorine-containing elastomer having a methylene group in its main chain. General form (I): CX １ X ３ =CX ２ R(-CZ) １ Z ２ -A ０ ) ｍ (In the formula, X １ and X ３ are each independently F, Cl, H or CF ３ and X ２ is H, F, an alkyl group or a fluorine-containing alkyl group; A ０ is an anionic group; R is a linking group; Z １ and Z ２ are each independently H, F, an alkyl group or a fluorine-containing alkyl group; and m is an integer of 1 or more.

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