Process for producing aqueous dispersion of fluoroelastomer and aqueous dispersion of fluoroelastomer

Abstract

Provided is a method for producing a fluorine-containing elastomer aqueous dispersion, which polymerizes a fluorine-containing monomer in the presence of a compound (1) having an aromatic ring, a hydrophilic group, and an unsaturated double bond, and an aqueous medium, thereby producing an aqueous dispersion of a fluorine-containing elastomer having -CH2- in the main chain.

Description

Technical Field

[0001] This invention relates to a method for manufacturing an aqueous dispersion of a fluorinated elastomer and to the aqueous dispersion of the fluorinated elastomer. Background Technology

[0002] As a method for manufacturing fluorinated elastomers, polymerization methods using fluorinated surfactants or non-fluorinated surfactants are known.

[0003] For example, Patent Document 1 proposes the following scheme: in an emulsion polymerization process for manufacturing a fluorinated elastomer having at least 58% by mass of fluorine, the inclusion formula CH3-(CH2) is used. n An aqueous solution of a surfactant of the formula CH3-(CH2)[-SO3M [where n is an integer from 6 to 17 or a mixture thereof, and M is a cation having a valence of 1] in a specified amount. n An aqueous solution of a surfactant containing the formula -C6H4-SO3M [where n is an integer from 6 to 17 or a mixture thereof, and M is a cation having a valence of 1], or containing the formula CH3-(CH2]. n -CH=CH-CH2-SO3M [where n is an integer from 6 to 17 or a mixture thereof, and M is a cation with a valence of 1] is a specified amount of an aqueous solution of a surfactant.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Publication No. 2004-510850 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] The purpose of this invention is to provide a method for manufacturing an aqueous dispersion of fluorinated elastomer, which can inhibit the adhesion of fluorinated elastomer to the polymerization tank and generate a sufficient number of fluorinated elastomer particles at a sufficient polymerization rate.

[0009] Methods for solving problems

[0010] According to the present invention, a method for manufacturing an aqueous dispersion of a fluorinated elastomer is provided, wherein a fluorinated monomer is polymerized in the presence of a compound (1) having an aromatic ring, a hydrophilic group and an unsaturated double bond and an aqueous medium, thereby producing an aqueous dispersion of a fluorinated elastomer containing -CH2- in the main chain.

[0011] Compound (1) is preferably selected from at least one of the groups consisting of compounds represented by general formulas (1-1) to (1-4).

[0012] General formula (1-1):

[0013] [Chemistry 1]

[0014]

[0015] General formula (1-2):

[0016] [Chemistry 2]

[0017]

[0018] General formula (1-3):

[0019] [Chemistry 3]

[0020]

[0021] General formula (1-4):

[0022] [Chemistry 4]

[0023]

[0024] (In each formula, ring A and ring B are aromatic rings with or without substituents;)

[0025] R 1 ~R 3 Each is independently H, halogen atom, alkyl group or -R 4 The group represented by -Z, in the above alkyl group, at least one hydrogen atom bonded to a carbon atom can be represented by -R. 4 -Z indicates the group substitution;

[0026] R 4 It is a single bond or an alkylene group;

[0027] R 5 It is a single bond or an alkylene group;

[0028] x is an integer greater than or equal to 1;

[0029] Z is -SO3M, -OSO3M, -COOM, -P(=O)(OM)2, -OP(O)(OM)2, -B(OM)2 or -OB(OM)2;

[0030] M represents H, a metal atom, and NR. 6 4. Imidazolium with or without substituents, pyridinium with or without substituents, or phosphatonium with or without substituents;

[0031] R 6 Independently, it is either H or an organic group, R 6 Any two of them can bond together to form a ring.

[0032] Ring A is preferably represented by any of the following formulas.

[0033] [Chemistry 5]

[0034]

[0035] (The curves indicate bonding positions. In any aromatic ring, the hydrogen atom bonded to the carbon atom can be replaced by a substituent.)

[0036] Ring B is preferably represented by any of the following formulas.

[0037] [Chemistry 6]

[0038]

[0039] (The curves indicate bonding positions. In any aromatic ring, the hydrogen atom bonded to the carbon atom can be replaced by a substituent.)

[0040] The number of carbon atoms in compound (1) is preferably 6 to 30.

[0041] The amount of compound (1) relative to the above-mentioned aqueous medium is preferably 3 ppm to 5000 ppm by mass.

[0042] Preferably, after adding compound (1) to the polymerization system, a polymerization initiator is added, thereby initiating the polymerization of the fluorinated monomer.

[0043] The fluorinated monomers mentioned above are preferably vinylidene fluoride or tetrafluoroethylene.

[0044] The preferred fluorinated monomer is vinylidene fluoride.

[0045] Preferably, the above-mentioned fluorinated monomer is further polymerized in the presence of a fluorinated compound (A) represented by general formula (A).

[0046] General formula (A): CX i X k =CX j R a -(CZ 1 Z 2 ) k -Y 3

[0047] (where X) i X j and X k Each can be independently F, Cl, H or CF3;

[0048] Y 3 It is a hydrophilic group;

[0049] R a It is a linking group;

[0050] Z 1 and Z 2 Each can be independently H, F, or CF3;

[0051] k is 0 or 1.

[0052] Among them, X i X k X j R a Z 1 and Z 2 At least one of them contains F.

[0053] Where, when k is 0, R a (A linking group other than a single bond.)

[0054] Preferably, the above-mentioned fluorinated monomers are further polymerized in the presence of a chain transfer agent.

[0055] The above-mentioned fluorinated monomers are preferably polymerized at 10℃ to 120℃.

[0056] The above-mentioned fluorinated monomers are preferably polymerized at a temperature of 0.5 MPaG to 10 MPaG.

[0057] The Mooney viscosity (ML1+10 (100℃)) of the above-mentioned fluorinated elastomer is preferably 10 to 130.

[0058] The average particle size of the above-mentioned fluorinated elastomer is preferably below 500 nm.

[0059] In addition, according to the present invention, a fluorinated elastomer is provided, which contains a monomer unit based on a compound (1) having an aromatic ring, a hydrophilic group and an unsaturated double bond, and contains -CH2- in the main chain.

[0060] In addition, according to the present invention, an aqueous dispersion of a fluorinated elastomer is provided, which contains the above-mentioned fluorinated elastomer and an aqueous medium.

[0061] The effects of the invention

[0062] According to the present invention, a method for manufacturing an aqueous dispersion of fluorinated elastomer can be provided, which can inhibit the adhesion of fluorinated elastomer to the polymerization tank, and at the same time produce a sufficient number of fluorinated elastomer particles at a sufficient polymerization rate. Detailed Implementation

[0063] Before describing specific embodiments of the present invention, some terms used in the present invention will be defined or explained.

[0064] In this invention, fluorinated elastomers refer to amorphous fluorinated polymers. "Amorphous" means that the melting peak (ΔH) observed in differential scanning calorimetry (DSC) (heating temperature 10°C / min) or differential thermal analysis (DTA) (heating rate 10°C / min) of the fluorinated polymer is below 4.5 J / g. Fluorinated elastomers exhibit elastomeric properties through crosslinking. Elastomeric properties refer to the ability to stretch the polymer and maintain its original length when the force required to stretch the polymer is no longer applied.

[0065] In this invention, a perfluorinated monomer refers to a monomer whose molecule does not contain carbon-hydrogen bonds. The aforementioned perfluorinated monomer may also be a monomer in which several fluorine atoms bonded to carbon atoms are replaced by chlorine atoms, in addition to carbon and fluorine atoms; or it may be a monomer in which nitrogen, oxygen, sulfur, phosphorus, boron, or silicon atoms are present in addition to carbon atoms. Preferably, the perfluorinated monomer in which all hydrogen atoms are replaced by fluorine atoms is a preferred embodiment. The aforementioned perfluorinated monomers do not contain monomers that provide crosslinking groups.

[0066] Monomers providing crosslinking sites refer to monomers (vulcanization point monomers) that provide crosslinking sites to fluoropolymers for forming crosslinks through a curing agent. Monomers providing crosslinking sites include monomers that provide crosslinking groups.

[0067] In this invention, the content of each monomer unit constituting the fluorinated elastomer can be calculated by appropriately combining NMR, FT-IR, elemental analysis, and fluorescence X-ray analysis according to the type of monomer.

[0068] In this invention, "organic group" refers to a group containing one or more carbon atoms, or a group formed by removing one hydrogen atom from an organic compound.

[0069] Examples of this "organic group" include:

[0070] Alkyl groups that can have more than one substituent

[0071] Alkenes that can have more than one substituent

[0072] Alkyne groups can have more than one substituent.

[0073] Cycloalkyl groups can have more than one substituent.

[0074] Cycloalkenyl groups can have more than one substituent.

[0075] Cyclodiene groups can have more than one substituent.

[0076] Aryl groups can have more than one substituent.

[0077] Aryl groups can have more than one substituent.

[0078] Non-aromatic heterocyclic groups that can have more than one substituent

[0079] Heteroaryl groups that can have more than one substituent

[0080] cyano,

[0081] formyl group,

[0082] RaO-、

[0083] RaCO-、

[0084] RaSO2-、

[0085] RaCOO-、

[0086] RaNRaCO-、

[0087] RaCONRa-、

[0088] RaOCO-、

[0089] RaOSO2-, and

[0090] RaNRbSO2-

[0091] (In these formulas, Ra is independently...)

[0092] Alkyl groups that can have more than one substituent

[0093] Alkenes that can have more than one substituent

[0094] Alkyne groups can have more than one substituent.

[0095] Cycloalkyl groups can have more than one substituent.

[0096] Cycloalkenyl groups can have more than one substituent.

[0097] Cyclodiene groups can have more than one substituent.

[0098] Aryl groups can have more than one substituent.

[0099] Aryl groups can have more than one substituent.

[0100] It can be a non-aromatic heterocyclic group with more than one substituent, or

[0101] Heteroaryl groups can have more than one substituent.

[0102] Rb is independently H or may be an alkyl group having more than one substituent.

[0103] As the aforementioned organic group, it is preferable to have an alkyl group having one or more substituents.

[0104] Furthermore, in this invention, "substituent" refers to a group capable of substitution. Examples of such "substituents" include: aliphatic groups, aromatic groups, heterocyclic groups, acyl groups, acyloxy groups, amide groups, aliphatic oxy groups, aromatic oxy groups, heterocyclic oxy groups, aliphatic oxycarbonyl groups, aromatic oxycarbonyl groups, heterocyclic oxycarbonyl groups, carbamoyl groups, aliphatic sulfonyl groups, aromatic sulfonyl groups, heterocyclic sulfonyl groups, aliphatic sulfonyloxy groups, aromatic sulfonyloxy groups, heterocyclic sulfonyloxy groups, amino sulfonyl groups, aliphatic sulfonamide groups, aromatic sulfonamide groups, heterocyclic sulfonamide groups, amino groups, and aliphatic groups. Aliphatic amino, aromatic amino, heterocyclic amino, aliphatic oxycarbonyl amino, aromatic oxycarbonyl amino, heterocyclic oxycarbonyl amino, aliphatic sulfinyl, aromatic sulfinyl, aliphatic thio, aromatic thio, hydroxyl, cyano, sulfonyl, carboxyl, aliphatic oxyamino, aromatic oxyamino, carbamoylamino, aminosulfonylamino, halogen atom, aminosulfonylcarbamoyl, carbamoylaminosulfonyl, dialiphatic oxyphosphine, and diaromatic oxyphosphine.

[0105] The aforementioned aliphatic groups can be saturated or unsaturated. Furthermore, they may include hydroxyl, aliphatic oxygen, carbamoyl, aliphatic oxygen carbonyl, aliphatic thio, amino, aliphatic amino, amide, carbamoylamino, etc. Examples of aliphatic groups include alkyl groups with a total carbon number of 1 to 8, preferably 1 to 4, such as methyl, ethyl, vinyl, cyclohexyl, carbamoylmethyl, etc.

[0106] The aforementioned aromatic groups may include, for example, nitro, halogen, aliphatic oxygen, carbamoyl, aliphatic oxygen carbonyl, aliphatic thio, amino, aliphatic amino, amide, carbamoylamino, etc. Examples of such aromatic groups include aryl groups with 6 to 12 carbon atoms, preferably 6 to 10 total carbon atoms, such as phenyl, 4-nitrophenyl, 4-acetylaminophenyl, 4-methanesulfonylphenyl, etc.

[0107] The aforementioned heterocyclic group may have halogen atoms, hydroxyl groups, aliphatic oxygen groups, carbamoyl groups, aliphatic oxygen carbonyl groups, aliphatic thio groups, amino groups, aliphatic amino groups, amide groups, carbamoylamino groups, etc. Examples of such heterocyclic groups include 5- to 6-membered heterocycles with a total number of carbon atoms of 2 to 12, preferably 2 to 10, such as 2-tetrahydrofuranyl and 2-pyrimidinyl groups.

[0108] The aforementioned acyl group may be aliphatic carbonyl, aryl carbonyl, heterocyclic carbonyl, hydroxyl, halogen atom, aromatic group, aliphatic oxygen group, carbamoyl, aliphatic oxygen carbonyl, aliphatic thio, amino, aliphatic amino, amide, carbamoylamino, etc. Examples of such acyl groups include those with a total carbon number of 2 to 8, preferably 2 to 4, such as acetyl, propionyl, benzoyl, 3-pyridine carbonyl, etc.

[0109] The aforementioned amide groups may have aliphatic groups, aromatic groups, heterocyclic groups, etc., such as acetylamino, benzoylamino, 2-pyridine carbonylamino, propionylamino, etc. Examples of such amide groups include amide groups with a total carbon number of 2 to 12, preferably 2 to 8, and alkyl carbonylamino groups with a total carbon number of 2 to 8, such as acetylamino, benzoylamino, 2-pyridine carbonylamino, propionylamino, etc.

[0110] The aforementioned aliphatic oxycarbonyl group can be saturated or unsaturated. Furthermore, it can be hydroxyl, aliphatic oxy, carbamoyl, aliphatic oxycarbonyl, aliphatic thio, amino, aliphatic amino, amide, carbamoylamino, etc. Examples of aliphatic oxycarbonyl groups include alkoxycarbonyl groups with a total carbon number of 2 to 8, preferably 2 to 4, such as methoxycarbonyl, ethoxycarbonyl, tert-butoxycarbonyl, etc.

[0111] The aforementioned carbamoyl group may have an aliphatic group, an aromatic group, a heterocyclic group, etc. Examples of the aforementioned carbamoyl group include unsubstituted carbamoyl groups and alkyl carbamoyl groups with a total number of carbon atoms of 2 to 9. Preferred examples include unsubstituted carbamoyl groups, alkyl carbamoyl groups with a total number of carbon atoms of 2 to 5, such as N-methylcarbamoyl groups, N,N-dimethylcarbamoyl groups, and N-phenylcarbamoyl groups.

[0112] The aforementioned aliphatic sulfonyl groups can be saturated or unsaturated. Furthermore, they can include hydroxyl groups, aromatic groups, aliphatic oxygen groups, carbamoyl groups, aliphatic oxygen carbonyl groups, aliphatic thio groups, amino groups, aliphatic amino groups, amide groups, carbamoylamino groups, etc. Examples of aliphatic sulfonyl groups include alkyl sulfonyl groups with a total carbon number of 1 to 6, preferably 1 to 4, such as methanesulfonyl groups.

[0113] The aforementioned aromatic sulfonyl groups may have hydroxyl, aliphatic, aliphatic oxygen, carbamoyl, aliphatic oxygen carbonyl, aliphatic thio, amino, aliphatic amino, amide, carbamoylamino, etc. Examples of such aromatic sulfonyl groups include arylsulfonyl groups with a total number of carbon atoms of 6 to 10, such as benzenesulfonyl groups.

[0114] The aforementioned amino groups can have aliphatic groups, aromatic groups, heterocyclic groups, etc.

[0115] The aforementioned acylamino group may be, for example, acetylamino, benzoylamino, 2-pyridine carbonylamino, propionylamino, etc. Examples of such acylamino groups include those with a total carbon number of 2 to 12, preferably 2 to 8, and more preferably alkyl carbonylamino groups with a total carbon number of 2 to 8, such as acetylamino, benzoylamino, 2-pyridine carbonylamino, propionylamino, etc.

[0116] The aforementioned aliphatic sulfonamide group, aromatic sulfonamide group, and heterocyclic sulfonamide group can be, for example, methylsulfonamide group, benzenesulfonamide group, 2-pyridinesulfonamide group, etc.

[0117] The aforementioned aminosulfonyl group may have an aliphatic group, an aromatic group, a heterocyclic group, etc. Examples of the aforementioned aminosulfonyl group include aminosulfonyl, alkyl aminosulfonyl with 1 to 9 total carbon atoms, dialkyl aminosulfonyl with 2 to 10 total carbon atoms, aryl aminosulfonyl with 7 to 13 total carbon atoms, heterocyclic aminosulfonyl with 2 to 12 total carbon atoms, more preferably aminosulfonyl, alkyl aminosulfonyl with 1 to 7 total carbon atoms, dialkyl aminosulfonyl with 3 to 6 total carbon atoms, aryl aminosulfonyl with 6 to 11 total carbon atoms, heterocyclic aminosulfonyl with 2 to 10 total carbon atoms, such as aminosulfonyl, methyl aminosulfonyl, N,N-dimethylaminosulfonyl, phenyl aminosulfonyl, 4-pyridine aminosulfonyl, etc.

[0118] The aforementioned aliphatic oxygen groups can be saturated or unsaturated, and may include methoxy, ethoxy, isopropoxy, cyclohexyloxy, methoxyethoxy, etc. Examples of aliphatic oxygen groups include alkoxy groups with a total carbon number of 1 to 8, preferably 1 to 6, such as methoxy, ethoxy, isopropoxy, cyclohexyloxy, methoxyethoxy, etc.

[0119] The aforementioned aromatic amino groups and heterocyclic amino groups may have aliphatic groups, aliphatic oxygen groups, halogen atoms, carbamoyl groups, heterocyclic groups fused with the aryl group, and aliphatic oxygen carbonyl groups. Preferably, they may have aliphatic groups with a total number of carbon atoms of 1 to 4, aliphatic oxygen groups with a total number of carbon atoms of 1 to 4, halogen atoms, carbamoyl groups with a total number of carbon atoms of 1 to 4, nitro groups, and aliphatic oxygen carbonyl groups with a total number of carbon atoms of 2 to 4.

[0120] The aforementioned aliphatic thio groups can be saturated or unsaturated. In addition, examples include alkylthio groups with a total number of carbon atoms of 1 to 8, more preferably 1 to 6, such as methylthio, ethylthio, carbamoylmethylthio, tert-butylthio, etc.

[0121] The aforementioned carbamoylamino group may have an aliphatic group, an aryl group, a heterocyclic group, etc. Examples of the aforementioned carbamoylamino group include carbamoylamino, alkyl carbamoylamino with 2 to 9 total carbon atoms, dialkyl carbamoylamino with 3 to 10 total carbon atoms, aryl carbamoylamino with 7 to 13 total carbon atoms, and heterocyclic carbamoylamino with 3 to 12 total carbon atoms. Preferably, carbamoylamino, alkyl carbamoylamino with 2 to 7 total carbon atoms, dialkyl carbamoylamino with 3 to 6 total carbon atoms, aryl carbamoylamino with 7 to 11 total carbon atoms, and heterocyclic carbamoylamino with 3 to 10 total carbon atoms, such as carbamoylamino, methyl carbamoylamino, N,N-dimethyl carbamoylamino, phenyl carbamoylamino, 4-pyridine carbamoylamino, etc.

[0122] In this invention, the range represented by the endpoints includes all values ​​contained in that range (for example, 1 to 10 includes 1.4, 1.9, 2.33, 5.75, 9.98, etc.).

[0123] In this invention, the description of "at least 1" includes all values ​​greater than 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.).

[0124] The specific embodiments of the present invention will be described in detail below, but the present invention is not limited to the following embodiments.

[0125] In the manufacturing method of the present invention, in order to produce an aqueous dispersion of fluorinated elastomer, fluorinated monomers are polymerized in the presence of compound (1) and an aqueous medium. In particular, due to the use of compound (1), the manufacturing method of the present invention enables the production of a sufficient number of fluorinated elastomer particles at a sufficient polymerization rate while suppressing the adhesion of fluorinated elastomers to the polymerization tank.

[0126] Compound (1) has an aromatic ring, a hydrophilic group and an unsaturated double bond.

[0127] In this invention, an aromatic ring refers to a ring structure that possesses aromatic properties. Aromatic rings include monocyclic aromatic rings such as benzene rings, condensed aromatic rings such as naphthalene rings, aromatic rings formed by single bonds of phenyl groups such as biphenyl rings, and heteroaromatic rings such as furan rings.

[0128] The aromatic ring can be either a monocyclic or polycyclic ring, but is preferably a monocyclic ring. The number of aromatic rings contained in compound (1) is preferably 1 to 5, more preferably 1 or 2, and even more preferably 1. The aromatic ring can be either a carbocyclic or heterocyclic ring, but is preferably a carbocyclic ring.

[0129] The aromatic ring may have substituents. That is, the aromatic ring may be a substituted or unsubstituted aromatic ring. Examples of substituents include the groups mentioned above, wherein halogen atoms, hydroxyl groups, alkyl groups, phenyl groups, or fluorophenyl groups are preferred, and F, Cl, hydroxyl groups, CH3 groups, or p-fluorophenyl groups are more preferred.

[0130] In this invention, a hydrophilic group refers to a group that exhibits affinity for aqueous media. Examples of hydrophilic groups include anionic hydrophilic groups, cationic hydrophilic groups, and nonionic hydrophilic groups. Compound (1) may have only anionic hydrophilic groups or only nonionic hydrophilic groups. The number of hydrophilic groups in compound (1) may be 1 to 4, 1 to 3, 1 to 2, or 1.

[0131] As a hydrophilic group, for example, from the perspective of being able to further suppress the adhesion of fluorinated elastomers to the polymerization tank while generating a larger amount of fluorinated elastomer particles at a higher polymerization rate, -SO3M, -OSO3M, -COOM, -P(=O)(OM)2, -OP(O)(OM)2, -B(OM)2 or -OB(OM)2 are preferred, -SO3M, -OSO3M or -COOM are more preferred, and -SO3M is even more preferred.

[0132] M represents H, a metal atom, and NR. 6 4. Imidazolium with or without substituents, pyridinium with or without substituents, or phosphonium with or without substituents.

[0133] R 6 Independently, it is either H or an organic group, R 6 Any two of them can bond together to form a ring. Alkyl groups are preferred as organic groups. As R... 6 H or C are preferred 1-10 Organic groups, more preferably H or C 1-4 The organic groups, preferably H or C, are preferred. 1-4 Alkyl groups, with H being the most preferred.

[0134] As metal atoms, monovalent or divalent metal atoms can be cited, preferably alkali metals (group 1) or alkaline earth metals (group 2), and more preferably Na, K or Li.

[0135] As for M, H, metal atoms, or NR are preferred, based on the ability to further suppress the adhesion of fluorinated elastomers to the polymerization bath and to generate a larger amount of fluorinated elastomer particles at a higher polymerization rate. 6 4. More preferably, H, Na, K, or NR 6 4. Further preferred elements include H, Na, K, or NH4.

[0136] As an unsaturated double bond, a free radical polymerizable unsaturated double bond is preferred, but a vinyl bond is also acceptable.

[0137] Regarding the number of carbon atoms in compound (1), from the perspective of further suppressing the adhesion of fluorinated elastomers to the polymerization tank and simultaneously producing a larger amount of fluorinated elastomer particles at a higher polymerization rate, 6 to 80 is preferred, more preferably 8 to 40, further preferably 8 to 30, and particularly preferably 8 to 20. In this invention, the number of carbon atoms in compound (1) does not include the number of carbon atoms in the hydrophilic groups contained in compound (1).

[0138] As compound (1), a fluorine-free compound is preferred.

[0139] Compound (1) is generally water-soluble. The solubility of compound (1) in water is more than 0.1 g per 100 g of water.

[0140] In the manufacturing method of the present invention, one or more compounds may be used as compound (1). As compound (1), a compound having only anionic hydrophilic groups may be used, a compound having only nonionic hydrophilic groups may be used, or a compound containing anionic hydrophilic groups and a compound containing nonionic hydrophilic groups may be used in combination.

[0141] Compound (1) is preferably at least one compound selected from the group consisting of compounds represented by general formulas (1-1) to (1-4).

[0142] General formula (1-1):

[0143] [Chemistry 7]

[0144]

[0145] General formula (1-2):

[0146] [Chemistry 8]

[0147]

[0148] General formula (1-3):

[0149] [Chemistry 9]

[0150]

[0151] General formula (1-4):

[0152] [Chemistry 10]

[0153]

[0154] In general formulas (1-1) to (1-4), R 1 ~R3 Each is independently H, halogen atom, alkyl group or -R 4 -Z represents the group.

[0155] The alkyl group is not particularly limited, and examples include straight-chain, branched, or cyclic alkyl groups. When the alkyl group has 2 or more carbon atoms, it may contain an ether bond. The number of carbon atoms in the alkyl group is preferably 1 or more, preferably 20 or less, more preferably 10 or less, further preferably 5 or less, and particularly preferably 3 or less.

[0156] In an alkyl group, at least one hydrogen atom bonded to a carbon atom can be replaced by a substituent. Besides the groups mentioned above, -R can also be cited as a substituent. 4 The group indicated by -Z. The -R group present in compound (1). 4 The number of groups represented by -Z is preferably 1 or more, preferably 8 or less, more preferably 5 or less, further preferably 4 or less, and particularly preferably 3 or less.

[0157] As an alkyl group, an alkyl group that does not contain a fluorine atom is preferred. Examples of alkyl groups include -CH3, -CH2CH3, -CH2CH2CH3, -CH(CH3)CH3, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc., among which -CH3 is preferred.

[0158] The preferred halogen atom is F, Cl, or Br, with F being more preferred.

[0159] As R 1 ~R 3 Preferably, H, F, -CH3, cyclopropyl, cyclopentyl or cyclohexyl are used, and more preferably H, -CH3, cyclopropyl, cyclopentyl or cyclohexyl are used.

[0160] In general formulas (1-1) to (1-4), R 4 It is a single bond or an alkylene group. Examples of alkylene groups include straight-chain or branched alkylene groups. The number of carbon atoms in the alkylene group is preferably 1 or more, 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-, more preferably -CH2-.

[0161] As R 4 Preferably, a single bond or -CH2-, more preferably a single bond.

[0162] In general formulas (1-1) and (1-4), R 5It is a single bond or an alkylene group. Examples of alkylene groups include straight-chain or branched alkylene groups. The number of carbon atoms in the alkylene group is preferably 1 or more, 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-, more preferably -CH2-.

[0163] As R 5 Preferably, a single bond or -CH2-, more preferably a single bond.

[0164] In general formulas (1-1) to (1-4), Z is -SO3M, -OSO3M, -COOM, -P(=O)(OM)2, -OP(O)(OM)2, -B(OM)2, or -OB(OM)2. M and R 6 As stated above.

[0165] In general formulas (1-1) and (1-4), x represents -R bonded to ring A. 4 The number of groups indicated by -Z is an integer greater than or equal to 1. The upper limit of x can be a number other than 1 from the total number of all ring-forming atoms constituting ring A, preferably 5 or less, more preferably 3 or less, and even more preferably 2 or less.

[0166] In general formulas (1-1) to (1-4), ring A and ring B are aromatic rings with or without substituents.

[0167] Ring A and ring B can be either monocyclic or polycyclic, 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 can be either carbocyclic or heterocyclic, preferably carbocyclic.

[0168] As rings A and B, examples can be given.

[0169] Benzene ring, naphthalene ring, biphenyl ring, anthracene ring,

[0170] Furan ring, benzofuran ring,

[0171] Pyrrole ring, indole ring, imidazole ring, benzimidazole ring, pyrazole ring, indazole ring,

[0172] Pyridine ring, quinoline ring, pyrazine ring, pyrimidine ring, pyridazine ring, triazine ring,

[0173] Thiophene ring, benzothiophene ring,

[0174] Oxazole ring, benzoxazole ring,

[0175] Thiazole rings, benzothiazole rings, etc., can all be substituted by substituents.

[0176] As a substituent that can exist in ring A and ring B, as long as it is -R 4 Substituents other than the group indicated by -Z are not particularly limited, and examples of the substituents mentioned above can be cited. Among them, halogen atoms, hydroxyl groups, alkyl groups, phenyl groups or fluorophenyl groups are preferred, and F, Cl, hydroxyl groups, CH3 or p-fluorophenyl groups are more preferred.

[0177] As for ring A in general formulas (1-1) and (1-4), the ring shown in any of the following formulas is preferred, based on the ability to further suppress the adhesion of fluorinated elastomers to the polymerization tank and at the same time generate a larger amount of fluorinated elastomer particles at a higher polymerization rate.

[0178] [Chemistry 11]

[0179]

[0180] In the above formulas, the curves represent the carbon atoms and R atoms constituting the vinyl group in the compounds shown in general formulas (1-1) and (1-4). 5 The carbon atom of the alkylene group or -R 4 The group indicated by -Z represents the bonding position of ring A. In any aromatic ring, the hydrogen atom bonded to the carbon atom can be replaced by a substituent, or the hydrogen atom bonded to the carbon atom may not be replaced by a substituent. Examples of substituents include those mentioned above, with halogen atoms, hydroxyl groups, alkyl groups, phenyl groups, or fluorophenyl groups being preferred, and F, Cl, hydroxyl groups, CH3, or p-fluorophenyl groups being more preferred.

[0181] As for ring B in general formulas (1-2) to (1-4), the ring shown in any of the following formulas is preferred, based on the ability to further suppress the adhesion of fluorinated elastomers to the polymerization tank and at the same time generate a larger amount of fluorinated elastomer particles at a higher polymerization rate.

[0182] [Chemistry 12]

[0183]

[0184] In the above formulas, the curves represent the bonding positions of ring B to the carbon atom constituting the vinyl group in the compounds shown in general formulas (1-2) to (1-4). In any aromatic ring, the hydrogen atom bonded to the carbon atom can be replaced by a substituent. Examples of substituents include those described above, among which halogen atoms, hydroxyl groups, alkyl groups, phenyl groups, or fluorophenyl groups are preferred, and F, Cl, hydroxyl groups, CH3 groups, or p-fluorophenyl groups are more preferred.

[0185] The number of carbon atoms in compound (1) is preferably 6 or more, more preferably 8 or more, more preferably 30 or less, more preferably 20 or less, further preferably 12 or less, and particularly preferably 10 or less, based on the ability to further suppress the adhesion of fluorinated elastomers to the polymerization bath and to produce a larger amount of fluorinated elastomer particles at a higher polymerization rate. In this invention, the number of carbon atoms in compound (1) does not include the number of carbon atoms that Z in compound (1) may contain.

[0186] As compound (1), the compounds shown in general formulas (1-1) to (1-4) are preferred.

[0187] As a compound (1), examples can be given.

[0188] p-Styrenesulfonic acid,

[0189] 2-Styrenesulfonic acid,

[0190] styrene sulfonic acid,

[0191] 4-(2-Propylene)benzoic acid,

[0192] 4-Vinylbenzoic acid,

[0193] 4-(1-Fluorovinyl)benzoic acid,

[0194] 2-Vinylphenylphosphonic acid (styrenephosphonic acid),

[0195] 4-Vinylphenylphosphonic acid (styrenephosphonic acid),

[0196] 4-Vinylbenzylphosphonic acid,

[0197] 4-Vinylphenylsulfuric acid,

[0198] 2-(1-Cyclopentylvinyl)benzoic acid,

[0199] (E)-2-(2-cyclopentylvinyl)benzoic acid,

[0200] 2-[(E)-2-cyclohexylvinyl)]benzoic acid,

[0201] (E)-2-(3-(naphth-1-yl)allyl)benzoic acid,

[0202] 1-Cinnamyl-2-naphthoic acid,

[0203] (Z)-2-(3-phenylallyl)benzoic acid,

[0204] 3-Allylnaphthalene-2-carboxylic acid,

[0205] 4-Vinylbenzene-1,3-dicarboxylic acid,

[0206] 4-Vinylphenylboronic acid,

[0207] 4-Allyl-2,3,5,6-Tetrafluorobenzoic acid,

[0208] 2-Allylbenzoic acid,

[0209] 2-Allyl-3-chlorobenzoic acid,

[0210] 2-Allyl-4-fluorobenzoic acid,

[0211] 2-Allyl-4-methylbenzoic acid,

[0212] 2-Allyl-5,6-dichlorobenzoic acid,

[0213] 2-(allyl-3,3-d2)-6-fluorobenzoic acid,

[0214] 4-Vinyl phthalic acid,

[0215] 3-Vinylbenzene-1,2-dicarboxylic acid,

[0216] 2-Vinyl terephthalic acid,

[0217] 5-Vinyl isophthalic acid,

[0218] 4-Vinnaphthalene-1,2-dicarboxylic acid,

[0219] 2-Phenylic acid,

[0220] trans-cinnamic acid,

[0221] 3-Phenylon-2-Butenoic acid,

[0222] 3-Methyl-4-phenyl-3-butenoic acid,

[0223] trans-2-hydroxycinnamic acid,

[0224] 5-Vinyl-2-furanic acid,

[0225] 2-Vinyl-3-furfuric acid,

[0226] 2-Methyl-5-vinyl-3-furfural,

[0227] 2-(4-fluorophenyl)-4-vinyl-2,5-dihydrofuran-3-carboxylic acid

[0228] 3,5-Dimethyl-4-vinyl-1H-pyrrole-2-carboxylic acid,

[0229] 2-Vinyl-3-thiophenic acid,

[0230] 5-Vinylpyridine-2-carboxylic acid,

[0231] And their salts, etc.

[0232] As compound (1), p-styrene sulfonic acid, 4-vinylbenzoic acid, 4-vinylphenylboronic acid and their salts (e.g., ammonium salts, sodium salts, potassium salts) are preferred, with the aim of further suppressing the adhesion of fluorinated elastomers to the polymerization bath and generating a larger amount of fluorinated elastomer particles at a higher polymerization rate.

[0233] Because compound (1) has unsaturated double bonds that are polymerizable by free radicals, it is presumed that if it is used in the above polymerization, it will react with fluorinated monomers in the early stage of the polymerization reaction, and will have hydrophilic groups from compound (1) to form particles with high stability. Therefore, if polymerization is carried out in the presence of compound (1), it is believed that the number of fluorinated elastomer particles produced during polymerization will increase.

[0234] The amount of compound (1) used in the polymerization of fluorinated monomers is preferably 3 ppm to 5000 ppm by mass relative to the aqueous medium, more preferably 5 ppm or more, further preferably 10 ppm or more, particularly preferably 20 ppm or more, most preferably 30 ppm or more, and more preferably 1000 ppm or less, further preferably 500 ppm or less, particularly preferably 300 ppm or less, and most preferably 200 ppm or less. By using the amount of compound (1) used in the polymerization of fluorinated monomers within the above range, it is possible to further suppress the adhesion of fluorinated elastomers to the polymerization tank, and at the same time generate a larger amount of fluorinated elastomer particles at a higher polymerization rate. The amount of compound (1) needs to be adjusted to an amount that allows for the smooth production of an aqueous dispersion of fluorinated elastomers. If the amount of compound (1) is too large, the polymerization rate may be significantly reduced, making it impossible to smoothly produce an aqueous dispersion of fluorinated elastomers.

[0235] In this invention, the amount of compound (1) is the amount of compound (1) added to the polymerization system. Therefore, the amount of compound (1) can be different from the amount of compound (1) present in the polymerization system. For example, when compound (1) is introduced into the fluorinated elastomer chain by copolymerization with a fluorinated monomer, the amount of compound (1) is the total amount of compound (1) present in the polymerization system that is not introduced into the fluorinated elastomer chain and compound (1) introduced into the fluorinated elastomer chain.

[0236] It is also preferable to adjust the amount of compound (1) according to the type of polymerization initiator used in the polymerization and the polymerization temperature.

[0237] When using a non-redox polymerization initiator as the polymerization initiator and performing polymerization at 40°C to 70°C, the amount of compound (1) relative to the aqueous medium is preferably 3 ppm to 300 ppm by mass, more preferably 3 ppm to 150 ppm by mass, even more preferably 5 ppm to 100 ppm by mass, and most preferably 8 ppm to 80 ppm by mass.

[0238] When using a non-redox polymerization initiator as the polymerization initiator and performing polymerization at a temperature above 70°C and below 98°C, the amount of compound (1) relative to the aqueous medium is preferably 3 to 500 ppm by mass, more preferably 5 to 300 ppm by mass, even more preferably 8 to 200 ppm by mass, and most preferably 10 to 180 ppm by mass.

[0239] When using a redox polymerization initiator as the polymerization initiator and performing polymerization at a temperature above 10°C and below 40°C, the amount of compound (1) relative to the aqueous medium is preferably 3 to 300 ppm by mass, more preferably 3 to 100 ppm by mass, even more preferably 5 to 80 ppm by mass, and most preferably 10 to 70 ppm by mass.

[0240] When using a redox polymerization initiator as the polymerization initiator and performing polymerization at 40°C to 70°C, the amount of compound (1) relative to the aqueous medium is preferably 3 ppm to 500 ppm by mass, more preferably 5 ppm to 300 ppm by mass, even more preferably 10 ppm to 200 ppm by mass, and most preferably 15 ppm to 150 ppm by mass.

[0241] When using a redox polymerization initiator as the polymerization initiator and performing polymerization at a temperature above 70°C and below 98°C, the amount of compound (1) relative to the aqueous medium is preferably 5 ppm to 500 ppm by mass, more preferably 8 ppm to 300 ppm by mass, even more preferably 15 ppm to 200 ppm by mass, and most preferably 20 ppm to 150 ppm by mass.

[0242] By keeping the amount of compound (1) during the polymerization of fluorinated monomers within the range described above, it is possible to further suppress the adhesion of fluorinated elastomers to the polymerization tank and generate a larger amount of fluorinated elastomer particles at a higher polymerization rate.

[0243] In the manufacturing method of the present invention, regarding the polymerization of fluorinated monomers, for example, compound (1) and an aqueous medium are added to a pressure-resistant polymerization tank equipped with a stirrer, the monomer is added after deoxygenation, the temperature is brought to a predetermined temperature, a polymerization initiator is added, and the reaction is initiated, thereby enabling the polymerization to proceed. Since the pressure decreases as the reaction proceeds, in order to maintain the initial pressure, additional monomers are continuously or intermittently supplied. When a predetermined amount of monomer has been supplied, the supply is stopped, the monomer in the reaction vessel is removed, the temperature is restored to room temperature, and the reaction is terminated.

[0244] In the manufacturing method of the present invention, there is no particular limitation on the timing of adding compound (1). Compound (1) can be added at any time during the polymerization reaction. Compound (1) can be added in a manner in which compound (1) and polymerization initiator coexist.

[0245] In the manufacturing method of the present invention, it is preferable that compound (1) is present in the polymerization system before the solid content concentration of the polymer (fluorinated elastomer) generated by polymerization reaches 1.0% by mass, more preferably 0.8% by mass, further preferably 0.5% by mass, particularly preferably 0.1% by mass, and most preferably 0% by mass. By adding compound (1) to the polymerization system before the polymer is generated by polymerization or when the polymer generated by polymerization is in small quantities, it is possible to further suppress the adhesion of the fluorinated elastomer to the polymerization tank and generate a larger amount of fluorinated elastomer particles at a higher polymerization rate. The above-mentioned solid content concentration is the total concentration of the polymer relative to the aqueous medium and the polymer (fluorinated elastomer).

[0246] Regarding the most preferred timing for adding compound (1) in the manufacturing method of the present invention, from the perspective of ease of controlling the polymerization reaction, it is before the solid content concentration of the polymer (fluorinated elastomer) generated by polymerization reaches 0% by mass. That is, in the manufacturing method of the present invention, compound (1) is preferably present before the polymerization reaction is initiated by having a polymerization initiator present in the polymerization system.

[0247] Furthermore, in the manufacturing method of the present invention, even if compound (1) is added to the polymerization system before polymer formation or when the polymer formation is in small quantities, compound (1) can be further added to the polymerization system thereafter. By adding compound (1), the adhesion of fluorinated elastomers to the polymerization tank can be further suppressed, while maintaining a high polymerization rate. When adding compound (1), it is preferable to adjust the total amount (addition amount) of compound (1) to reach the range of the preferred amount of compound (1) described above.

[0248] Aqueous media refers to liquids containing water. There are no particular limitations as long as an aqueous medium contains water; it can contain water along with non-fluorinated organic solvents such as alcohols, ethers, and ketones, and / or fluorinated organic solvents with a boiling point below 40°C.

[0249] In the manufacturing method of the present invention, it is preferable to polymerize the fluorinated monomer in the presence of a polymerization initiator, in addition to compound (1) and an aqueous medium. For example, in the manufacturing method of the present invention, the polymerization initiator can be added after compound (1) is added to the polymerization system, thereby initiating the polymerization of the fluorinated monomer. By polymerizing the fluorinated monomer without using a homopolymer of compound (1) and with the polymerization initiator present, it is possible to further suppress the adhesion of the fluorinated elastomer to the polymerization tank, and simultaneously produce a larger quantity of fluorinated elastomer particles at a higher polymerization rate.

[0250] Free radical polymerization initiators can be cited as examples of polymerization initiators. There are no particular limitations on the polymerization initiator as long as it can generate free radicals at the temperature required to polymerize fluorinated monomers; oil-soluble polymerization initiators, water-soluble polymerization initiators, etc., can be used, with water-soluble polymerization initiators being preferred. Furthermore, polymerization initiators can be combined with reducing agents to form redox initiators.

[0251] The amount of polymerization initiator used in the polymerization of fluorinated monomers is appropriately determined based on the type of monomer, the molecular weight of the target fluorinated elastomer, and the reaction rate. The amount of polymerization initiator is appropriately determined based on the molecular weight of the target fluorinated elastomer and the polymerization reaction rate, and is preferably 0.00001% to 10% by mass, more preferably 0.0001% to 1% by mass, relative to 100% of the total monomer mass.

[0252] Oil-soluble free radical polymerization initiators, water-soluble free radical polymerization initiators, or azo compounds can be used as polymerization initiators.

[0253] As an oil-soluble free radical polymerization initiator, it can be a known oil-soluble peroxide, such as the following peroxides as representative substances: diisopropyl peroxide, disec-butyl peroxide, and other dialkyl peroxide esters; tert-butyl peroxide, tert-butyl peroxyisobutyrate, and other peroxide esters; dialkyl peroxides such as di-tert-butyl peroxide; and bis(ω-hydro-dodecylfluoroheptanoyl) peroxide, bis(ω-hydro-tetradecylfluoroheptanoyl) peroxide, bis(ω-hydro-hexadecylfluorononanoyl) peroxide, bis(perfluorobutyryl) peroxide, bis(perfluoropentanoyl) peroxide, bis(perfluorohexanoyl) peroxide, bis(perfluoroheptanoyl) peroxide, bis(perfluorooctanoyl) peroxide, bis(perfluorooctanoyl) peroxide, etc. Oxides, di(perfluorononanoyl) peroxides, di(ω-chloro-hexafluorobutyryl) peroxides, di(ω-chloro-decafluorohexanoyl) peroxides, di(ω-chloro-tetrafluorooctanoyl) peroxides, ω-hydro-dodecanoyl-ω-hydrohexafluorononanoyl-peroxides, ω-chloro-hexafluorobutyryl-ω-chloro-decafluorohexanoyl-peroxides, ω-hydro-dodecanoyl-perfluorobutyryl-peroxides, di(dichloropentafluorobutyryl) peroxides, di(trichlorooctafluorohexanoyl) peroxides, di(tetrachloroundecanoyl) peroxides, di(pentachlorotetrafluorodecanoyl) peroxides, di(undecanoyltridodecanoyl)fluoroethoacyl) peroxides, etc., are all di[perfluoro(or fluorochloro)acyl] peroxides; etc.

[0254] Examples of azo compounds include azodicarboxylic acid esters, azodicarboxylic acid diamides, 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-dimethylpentanonitrile), 2,2'-azobis(2-methylpropanediamine) dihydrochloride, and 4,4'-azobis(4-cyanopentanoic acid).

[0255] As a water-soluble free radical polymerization initiator, it can be a known water-soluble peroxide, such as ammonium salts, potassium salts, and sodium salts of persulfate, perboric acid, perchloric acid, superphosphoric acid, and percarbonate; organic peroxides such as disuccinate peroxide and diglutaric acid peroxide; tert-butyl maleate peroxide; and tert-butyl hydroperoxide. It may also contain reducing agents such as sulfites, in amounts ranging from 0.1 to 20 times that of the peroxide.

[0256] As a water-soluble peroxide, from the perspective of ease of adjusting the amount of free radicals generated, salts of persulfate are preferred, with potassium persulfate (K2S2O8), ammonium persulfate ((NH4)2S2O8), and sodium persulfate (Na2S2O8) being the most preferred.

[0257] When using water-soluble peroxides for polymerization at temperatures above 45°C, it is preferable not to use a reducing agent.

[0258] For example, when polymerization is carried out at low temperatures below 60°C, a redox initiator that combines an oxidant and a reducing agent is preferably used as the polymerization initiator. That is, the above polymerization is preferably carried out in the presence of a redox initiator.

[0259] 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, diimides, oxalic acid, and metal salts of sulfites. Examples of persulfates include ammonium persulfate, potassium persulfate, and sodium persulfate. Examples of sulfites include sodium sulfite and ammonium sulfite. To improve the decomposition rate of the initiator, it is preferable to add copper or iron salts to the combination of redox initiators. Examples of copper salts include copper(II) sulfate, and examples of iron salts include ferric(II) sulfate. Furthermore, when using copper or iron salts, it is particularly preferable to add a chelating agent. A preferred chelating agent is disodium ethylenediaminetetraacetate dihydrate.

[0260] Examples of redox initiators include potassium permanganate / oxalic acid, ammonium persulfate / bisulfite / ferric sulfate (II), ammonium persulfate / sulfite / ferric sulfate (II), ammonium persulfate / sulfite, ammonium persulfate / ferric sulfate (II), manganese triacetate / oxalic acid, cerium ammonium nitrate / oxalic acid, bromate / sulfite, bromate / bisulfite, ammonium persulfate / sodium hydroxymethanesulfinate dihydrate, etc., with ammonium persulfate / sodium hydroxymethanesulfinate dihydrate being preferred.

[0261] When using a redox initiator, either the oxidant or the reducing agent can be added to the polymerization tank beforehand, followed by the addition of the other continuously or intermittently to initiate polymerization. For example, when using ammonium persulfate / sodium hydroxymethanesulfinate dihydrate, it is preferable to add ammonium persulfate to the polymerization tank and then continuously add sodium hydroxymethanesulfinate dihydrate thereto.

[0262] The amount of persulfate in the redox initiator is preferably 0.001% to 2.0% by mass, more preferably 0.01% to 1.5% by mass, and particularly preferably 0.05% to 1.0% by mass relative to the aqueous medium used in the polymerization.

[0263] The amount of reducing agent used relative to the aqueous medium used in the polymerization is preferably 1% to 30% by mass, more preferably 3% to 25% by mass, and particularly preferably 5% to 20% by mass.

[0264] Furthermore, the amount of the third component (such as the copper salt and iron salt mentioned above) relative to the aqueous medium used in the polymerization is preferably 0.001% to 0.5% by mass, more preferably 0.005% to 0.4% by mass, and particularly preferably 0.01% to 0.3% by mass.

[0265] In the manufacturing method of the present invention, the fluorinated monomers may be further polymerized in the presence of a chain transfer agent. Known substances can be used as chain transfer agents, such as hydrocarbons, esters, ethers, alcohols, ketones, halogenated compounds, carbonates, etc. Among these, isopentane, diethyl malonate, and ethyl acetate are preferred from the perspective of minimizing reaction rate reduction, and diiodide compounds such as I(CF2)4I, I(CF2)6I, and ICH2I are preferred from the perspective of being able to perform iodination at the polymer ends and be used as reactive polymers.

[0266] Bromine or iodine compounds are particularly preferred as chain transfer agents. Examples of polymerization methods using bromine or iodine compounds include iodine transfer polymerization and bromine transfer polymerization.

[0267] Iodine and bromine compounds are insoluble in water and difficult to emulsify. Therefore, emulsion polymerization is inherently limited and tends to require the extensive use of surfactants. The manufacturing method of this invention allows for the production of fluorinated elastomers even in the absence of conventionally used surfactants, through the polymerization of iodine or bromine compounds, such as iodine transfer polymerization or bromine transfer polymerization.

[0268] Iodine transfer polymerization is carried out by the following method: Due to the low dissociation energy of the carbon-iodine bond, it possesses free radical activity, participating in the chain transfer reaction during the free radical polymerization process. This utilizes the resulting free radical chain reactivation mechanism, leading to living free radical polymerization. Regarding the reaction conditions, known conditions can be appropriately used; there are no particular limitations. Conditions described, for example, those in "Polymer Proceedings, Vol. 49, No. 10, pp. 765-783, October 1992" and Japanese Patent Application Publication No. 53-3495 can be employed. Bromine compounds can be used instead of iodine compounds for the same polymerization; in this invention, such polymerization is referred to as bromine transfer polymerization.

[0269] Among these, iodine transfer polymerization is preferred based on factors such as polymerization reactivity and crosslinking reactivity.

[0270] Representative examples of bromine or iodine compounds include, for instance, the general formula:

[0271] R 8 I x Br y

[0272] (In the formula, x and y are integers from 0 to 2 and satisfy 1≤x+y≤2, R) 8 It is a saturated or unsaturated fluorocarbon or chlorofluorocarbon group with 1 to 16 carbon atoms, or a hydrocarbon group with 1 to 3 carbon atoms. 8 Compounds (with or without oxygen atoms). Iodine or bromine is introduced into the polymer using bromine or iodine compounds, acting as crosslinking points.

[0273] Examples of bromine and iodine compounds include, for instance, 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, and CFClBr₂. BrCF2CFClBr, CFBrClCFClBr, BrCF2CF2CF2Br, BrCF2CFBrOCF3, 1-bromo-2-iodoperfluoroethane, 1-bromo-3-iodoperfluoropropane, 1-bromo-4-iodoperfluorobutane, 2-bromo-3-iodoperfluorobutane, 3-bromo-4-iodoperfluoro-1-butene, 2-bromo-4-iodoperfluoro-1-butene, monoiodomonobromo-substituted derivatives of benzene, diiodomonobromo-substituted derivatives, and (2-iodoethyl) and (2-bromoethyl)-substituted derivatives, etc. These compounds can be used alone or in combination with each other.

[0274] Among these, compounds containing only iodine and not bromine are preferred from the perspectives of polymerization reactivity, crosslinking reactivity, and ease of acquisition. 1,4-diiodoperfluorobutane, 1,6-diiodoperfluorohexane, or 2-iodoperfluoropropane are preferred.

[0275] The amount of chain transfer agent relative to the total amount of monomers used in the polymerization is preferably 0.2 × 10⁻⁶. -3 mol% to 2 mol%, more preferably 1.0 × 10⁻⁶ -3 mol% ~ 1 mol%.

[0276] In the manufacturing method of the present invention, a fluorinated monomer (excluding compound (1) and fluorinated compound (A)) is polymerized. Examples of fluorinated monomers include vinylidene fluoride (VdF), tetrafluoroethylene (TFE), hexafluoropropylene (HFP), perfluoro(alkyl vinyl ether) (PAVE), trifluorochloroethylene (CTFE), trifluoroethylene, trifluoropropylene, tetrafluoropropylene, pentafluoropropylene, trifluorobutene, tetrafluoroisobutylene, hexafluoroisobutylene, fluorinated vinyl ether, and general formula (2):

[0277] CHX 1 =CX 2 Rf (2)

[0278] (where X) 1 and X 2 One of them is H, the other is F, and Rf is a straight-chain or branched fluoroalkyl group with 1 to 12 carbon atoms. Fluorine monomers (2) and other fluorine monomers.

[0279] As PAVE, perfluoro(methyl vinyl ether) (PMVE), perfluoro(ethyl vinyl ether) (PEVE), and perfluoro(propyl vinyl ether) (PPVE) are more preferred, with PMVE being particularly preferred.

[0280] Alternatively, as PAVE, the formula can also be used: CF2 = CFOCF2ORf c (where Rf) c It is a perfluorovinyl ether represented by a straight-chain or branched perfluoroalkyl group having 1 to 6 carbon atoms, a cyclic perfluoroalkyl group having 5 to 6 carbon atoms, or a straight-chain or branched perfluorooxyalkyl group having 2 to 6 carbon atoms containing 1 to 3 oxygen atoms. As a PAVE, for example, CF2=CFOCF2OCF3, CF2=CFOCF2OCF2CF3 or CF2=CFOCF2OCF2CF2OCF3 are preferred.

[0281] As the fluorinated monomer (2), it is preferred that Rf is a straight-chain fluoroalkyl monomer, and more preferably that Rf is a straight-chain perfluoroalkyl monomer. The number of carbon atoms in Rf is preferably 1 to 6.

[0282] Examples of fluorinated monomers (2) include CH2=CFCF3, CH2=CFCF2CF3, CH2=CFCF2CF2CF3, CH2=CFCF2CF2CF2CF3, CHF=CHCF3 (1,3,3,3-tetrafluoropropylene), CHF=CHCF3 (E-body), CHF=CHCF3 (Z-body), etc., among which 2,3,3,3-tetrafluoropropylene represented by CH2=CFCF3 is preferred.

[0283] In the manufacturing method of the present invention, from the perspective of further suppressing the adhesion of fluorinated elastomers to the polymerization tank and generating a larger amount of fluorinated elastomer particles at a higher polymerization rate, at least vinylidene fluoride or tetrafluoroethylene is preferably polymerized as the fluorinated monomer, and more preferably vinylidene fluoride is polymerized.

[0284] In the manufacturing method of the present invention, non-fluorinated monomers and fluorinated monomers can be polymerized together. Examples of non-fluorinated monomers include α-olefin monomers with 2 to 10 carbon atoms, such as ethylene, propylene, butene, and pentene; and alkyl vinyl ethers with 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. One or more of these monomers or compounds can be used.

[0285] According to the manufacturing method of the present invention, an aqueous dispersion containing a fluorinated elastomer having a methylene (-CH2-) in its main chain can be produced. As the fluorinated elastomer having a methylene (-CH2-) in its main chain (partially fluorinated elastomer), there is no particular limitation as long as it contains the chemical structure shown in -CH2-, and examples include fluorinated 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 fluorinated elastomer, for example, by polymerizing vinylidene fluoride, propylene, ethylene, 2,3,3,3-tetrafluoropropylene, etc.

[0286] As a fluorinated elastomer, it preferably contains, for example, materials selected from tetrafluoroethylene (TFE), vinylidene fluoride (VdF), and the general formula: CF2=CF-Rf a (where Rf) a For -CF3 or -ORf b (Rf b It is a structural unit of at least one monomer from the group consisting of perfluoroalkyl groups having 1 to 5 carbon atoms, representing perfluoroolefinic unsaturated compounds (e.g., hexafluoropropylene (HFP), perfluoro(alkyl vinyl ether) (PAVE), etc.). As a fluorinated elastomer, it preferably contains VdF units or TFE units.

[0287] More specifically, examples of fluorinated elastomers include VdF-based fluorinated elastomers, TFE / propylene (Pr)-based fluorinated elastomers, TFE / Pr / VdF-based fluorinated elastomers, ethylene (Et) / HFP-based fluorinated elastomers, Et / HFP / VdF-based fluorinated elastomers, Et / HFP / TFE-based fluorinated elastomers, and Et / TFE / PAVE-based fluorinated elastomers. Among these, VdF-based, TFE / Pr-based, TFE / Pr / VdF-based, or Et / TFE / PAVE-based fluorinated elastomers are preferred in terms of good heat aging resistance and oil resistance.

[0288] VdF-based fluorinated elastomers are fluorinated elastomers having VdF units. In VdF-based fluorinated elastomers, the total molar percentage of VdF units is preferably 20 mol% to 90 mol% of the total number of VdF units and monomer units from other monomers, more preferably 40 mol% to 85 mol%, further preferably 45 mol% to 80 mol%, and particularly preferably 50 mol% to 80 mol%.

[0289] As for other monomers in VdF-based fluorinated elastomers, there are no particular limitations as long as they are monomers that can copolymerize with VdF. For example, the aforementioned fluorinated monomers can be used.

[0290] As a VdF-based fluorinated elastomer, it is preferable to have 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 copolymers of VdF / fluorinated monomer (2). Furthermore, as other monomers besides VdF, it is more preferable to have at least one monomer selected from the group consisting of TFE, HFP, and PAVE.

[0291] As a VdF-based fluorinated elastomer, among these, preferably at least one copolymer is selected from the group consisting of VdF / HFP copolymer, VdF / TFE / HFP copolymer, VdF / fluorinated monomer (2) copolymer, VdF / PAVE copolymer, VdF / TFE / PAVE copolymer, VdF / HFP / PAVE copolymer and VdF / HFP / TFE / PAVE copolymer, more preferably at least one copolymer is selected from the group consisting of VdF / HFP copolymer, VdF / HFP / TFE copolymer, VdF / fluorinated monomer (2) copolymer and VdF / PAVE copolymer.

[0292] As a VdF / PAVE copolymer, a copolymer with a VdF / PAVE composition of (65-90) / (35-10) (mol%) is preferred.

[0293] In addition, a VdF / PAVE composition of (50-78) / (50-22) (mol%) is also a preferred option.

[0294] As a VdF / TFE / PAVE copolymer, a copolymer with a VdF / TFE / PAVE composition of (40-80) / (3-40) / (15-35) (mol%) is preferred.

[0295] As a VdF / HFP / PAVE copolymer, a copolymer with a VdF / HFP / PAVE composition of (65-90) / (3-25) / (3-25) (mol%) is preferred.

[0296] As a VdF / HFP / TFE / PAVE copolymer, a copolymer with a composition of (40-90) / (0-25) / (0-40) / (3-35) (mol%) is preferred, and a copolymer with a composition of (40-80) / (3-25) / (3-40) / (3-25) (mol%) is even more preferred.

[0297] As a copolymer of VdF / fluorinated monomer (2), it is preferable to have a copolymer in which the VdF / fluorinated monomer (2) unit is (85-20) / (15-80) (mol%), and the other monomer units besides VdF and fluorinated monomer (2) are 0-50 mol% of all monomer units. The mol% ratio of VdF / fluorinated monomer (2) unit is more preferably (80-20) / (20-80). In addition, a composition of VdF / fluorinated monomer (2) unit of (78-50) / (22-50) (mol%) is also a preferred option.

[0298] Furthermore, as a copolymer of VdF / fluorinated monomer (2), it is also preferred that the VdF / fluorinated monomer (2) unit is (85-50) / (15-50) (mol%), and the other monomer units besides VdF and fluorinated monomer (2) are 1 mol% to 50 mol% of all monomer units. As other monomers besides VdF and fluorinated monomer (2), preferred monomers are those listed as other monomers in VdF-based fluorinated elastomers, such as TFE, HFP, PMVE, perfluoroethyl vinyl ether (PEVE), PPVE, CTFE, trifluoroethylene, hexafluoroisobutylene, fluoroethylene, Et, Pr, alkyl vinyl ethers, and monomers that provide crosslinking groups, with PMVE, CTFE, HFP, and TFE being more preferred.

[0299] TFE / Pr fluorinated elastomers refer to fluorinated copolymers composed of 45 mol% to 70 mol% TFE and 55 mol% to 30 mol% Pr. In addition to these two components, a specific third component may also be included.

[0300] As a specific third component, it may include, for example, fluorinated monomers such as fluorinated olefins other than TFE (e.g., VdF, HFP, CTFE, perfluorinated (butylethylene) etc.), fluorinated vinyl ethers (perfluorinated (propyl vinyl ether), perfluorinated (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.), and vinyl esters (vinyl acetate, vinyl benzoate, vinyl crotonate, vinyl methacrylate, etc.); etc. The aforementioned specific third component may be one type or a combination of two or more types.

[0301] TFE / Pr-based fluorinated elastomers preferably contain VdF. In TFE / Pr-based fluorinated elastomers, the elastomer composed of TFE, Pr and VdF is called a TFE / Pr / VdF-based fluorinated elastomer.

[0302] TFE / Pr / VdF-based fluorinated elastomers may further include the aforementioned specific third component other than VdF. The aforementioned specific third component may be one type, or two or more types may be used in combination. The total content of the third component in the TFE / Pr-based fluorinated elastomer is preferably 35 mol% or less, more preferably 33 mol% or less, and even more preferably 31 mol% or less.

[0303] As an Et / HFP copolymer, the composition of Et / HFP is preferably (35-80) / (65-20) (mol%), more preferably (40-75) / (60-25) (mol%).

[0304] In the Et / HFP / TFE copolymer, the composition of Et / HFP / TFE is preferably (35-75) / (25-50) / (0-15) (mol%), more preferably (45-75) / (25-45) / (0-10) (mol%).

[0305] In the Et / TFE / PAVE copolymer, the composition of Et / TFE / PAVE is preferably (10-40) / (32-60) / (20-40) (mol%), more preferably (20-40) / (40-50) / (20-30) (mol%). PMVE is preferred as the PAVE.

[0306] As a fluorinated elastomer, a fluorinated elastomer containing VdF units is preferred, more preferably a VdF / HFP copolymer or a VdF / HFP / TFE copolymer, and particularly preferred is a copolymer with a VdF / HFP / TFE composition of (32-85) / (10-34) / (0-40) (mol%). As for the VdF / HFP / TFE composition, (32-85) / (15-34) / (0-34) (mol%) is more preferred, and (47-81) / (17-32) / (0-26) (mol%) is even more preferred.

[0307] For example, in the above-mentioned VdF / HFP copolymer, the composition of VdF / HFP is preferably (45-85) / (15-55) (mol%), more preferably (50-83) / (17-50) (mol%), even more preferably (55-81) / (19-45) (mol%), and particularly preferably (60-80) / (20-40) (mol%).

[0308] The above-described composition represents the main monomers of the fluorinated elastomer. In addition to the main monomers, monomers providing crosslinking groups can also be copolymerized. As monomers providing crosslinking groups, any suitable crosslinking groups can be introduced into the fluorinated elastomer according to the manufacturing method or crosslinking system. Examples include known polymeric compounds containing crosslinking groups such as iodine atoms, bromine atoms, carbon-carbon double bonds, cyano groups, carboxyl groups, hydroxyl groups, amino groups, and ester groups.

[0309] Compounds of general formula (3) can be cited as preferred monomers that provide crosslinking groups.

[0310] CY 1 2 = CY 2 R f 2 X 1 (3)

[0311] (where Y) 1 Y 2 It can be a fluorine atom, a hydrogen atom, or -CH3; R f 2 It is a straight-chain or branched fluorinated alkylene group that may have one or more ether-bonded oxygen atoms, may have an aromatic ring, and whose hydrogen atoms are partially or completely replaced by fluorine atoms; X 1 (It consists of iodine or bromine atoms.)

[0312] As monomers that provide crosslinking groups, examples include iodine- or bromine-containing monomers as shown in general formula (4) and iodine- or bromine-containing monomers as shown in general formulas (5) to (22), which can be used individually or in any combination.

[0313] CY 12 = CY 2 R f 3 CHR 1 -X 1 (4)

[0314] (where Y) 1 Y 2 X 1 Similar to the above, R f 3 A fluorinated alkylene group is a straight-chain or branched alkylene group that may have one or more ether-bonded oxygen atoms, with some or all hydrogen atoms replaced by fluorine atoms. Specifically, it can be a straight-chain or branched alkylene group with some or all hydrogen atoms replaced by fluorine atoms, a straight-chain or branched alkylene oxide with some or all hydrogen atoms replaced by fluorine atoms, or a straight-chain or branched alkylene oxide with some or all hydrogen atoms replaced by fluorine atoms; R 1 (for hydrogen atoms or methyl groups)

[0315] CY 4 2 = CY 4 (CF2) n -X 1 (5)

[0316] (where Y) 4 Whether they are the same or different, they are hydrogen atoms or fluorine atoms, and n is an integer from 1 to 8.

[0317] CF2 = CFCF2R f 4 -X 1 (6)

[0318] (where R is in the formula) 4 For -(OCF2) n -or-(OCF(CF3)) n - (n is an integer from 0 to 5)

[0319] CF2 = CFCF2(OCF(CF3)CF2) m (OCH2CF2CF2) n OCH2CF2-X 1 (7)

[0320] (In the formula, m is an integer from 0 to 5, and n is an integer from 0 to 5)

[0321] CF2 = CFCF2(OCH2CF2CF2) m (OCF(CF3)CF2) n OCF(CF3)-X 1 (8)

[0322] (In the formula, m is an integer from 0 to 5, and n is an integer from 0 to 5)

[0323] CF2 = CF(OCF2CF(CF3)) m O(CF2) n -X 1 (9)

[0324] (In the formula, m is an integer from 0 to 5, and n is an integer from 1 to 8)

[0325] CF2 = CF(OCF2CF(CF3)) m -X 1 (10)

[0326] (In the formula, m is an integer from 1 to 5)

[0327] CF2 = CFOCF2(CF(CF3)OCF2) n CF(-X 1 )CF3 (11)

[0328] (In the formula, n is an integer from 1 to 4)

[0329] CF2 = CFO(CF2) n OCF(CF3)-X 1 (12)

[0330] (In the formula, n is an integer from 2 to 5)

[0331] CF2 = CFO(CF2) n -(C6H4)-X 1 (13)

[0332] (In the formula, n is an integer from 1 to 6)

[0333] CF2 = CF(OCF2CF(CF3)) n OCF2CF(CF3)-X 1 (14)

[0334] (In the formula, n is an integer from 1 to 2)

[0335] CH2=CFCF2O(CF(CF3)CF2O) n CF(CF3)-X 1 (15)

[0336] (In the formula, n is an integer from 0 to 5)

[0337] CF2 = CFO(CF2CF(CF3)O) m (CF2) n -X 1 (16)

[0338] (In the formula, m is an integer from 0 to 5, and n is an integer from 1 to 3)

[0339] CH2=CFCF2OCF(CF3)OCF(CF3)-X 1 (17)

[0340] CH2=CFCF2OCH2CF2-X 1 (18)

[0341] CF2 = CFO(CF2CF(CF3)O) m CF2CF(CF3)-X 1 (19)

[0342] (In the formula, m is an integer greater than or equal to 0)

[0343] CF2 = CFOCF(CF3)CF2O(CF2) n -X 1 (20)

[0344] (In the formula, n is an integer greater than or equal to 1)

[0345] CF2 = CFOCF2OCF2CF(CF3)OCF2-X 1 (twenty one)

[0346] CH2=CH-(CF2) n X 1 (twenty two)

[0347] (In the formula, n is an integer from 2 to 8)

[0348] (In general formulas (5) to (22), X) 1 Same as above)

[0349] As a monomer containing iodine or bromine as shown in general formula (4), iodine-containing fluorinated vinyl ethers of general formula (23) are preferably examples.

[0350] [Chemistry 13]

[0351]

[0352] (In the formula, m is an integer from 1 to 5, and n is an integer from 0 to 3)

[0353] More specifically, examples can be given.

[0354] [Chemistry 14]

[0355] ICH2CF2CF2OCF=CF2、I(CH2CF2CF2a)2CF=CF2、I(CH2CF2CF2O)3CF=CF2、

[0356]

[0357] Among these, ICH2CF2CF2OCF=CF2 is preferred.

[0358] As the iodine- or bromine-containing monomers represented by general formula (5), more specifically, ICF2CF2CF=CH2 and I(CF2CF2)2CF=CH2 are preferred examples.

[0359] As a monomer containing iodine or bromine as shown in general formula (9), more specifically, I(CF2CF2)2OCF=CF2 is preferably an example.

[0360] As the iodine- or bromine-containing monomers represented by general formula (22), more specifically, CH2=CHCF2CF2I and I(CF2CF2)2CH=CH2 are preferred examples.

[0361] Additionally, the formula: R 2 R 3 C = CR 4 -Z-CR 5 =CR 6 R 7

[0362] (where R is in the formula) 2 R 3 R 4 R 5 R 6 and R 7 Whether identical or different, all are H or alkyl groups having 1 to 5 carbon atoms; Z is a straight-chain or branched diene compound containing oxygen atoms, preferably at least partially fluorinated, having 1 to 18 carbon atoms, and either alkylene or cycloalkylene, or (per)fluoropolyalkylene oxide, and is also preferably used as a monomer to provide crosslinking groups. It should be noted that in this invention, "(per)fluoropolyalkylene oxide" refers to "fluoropolyalkylene oxide or perfluoropolyalkylene oxide".

[0363] Z is preferably a (per)fluoroalkylene group having 4 to 12 carbon atoms, R 2 R 3 R 4 R 5 R 6 and R 7 Hydrogen atoms are preferred.

[0364] When Z is a (per)fluoropolyalkylene oxide, the preferred formula is:

[0365] -(Q) p -CF₂O-(CF₂CF₂O) m -(CF2O) n -CF2-(Q) p -

[0366] (In the formula, Q is an alkylene group having 1 to 10 carbon atoms or an alkylene oxide having 2 to 10 carbon atoms, p is 0 or 1, m and n are integers in the m / n ratio range of 0.2 to 5 and the molecular weight of the (per)fluoropolyalkylene oxide is in the range of 500 to 10000, preferably 1000 to 4000.) The (per)fluoropolyalkylene oxide is shown in the formula. In this formula, Q is preferably derived from -CH2OCH2- and -CH2O(CH2CH2O). s Choose from CH2- (s = 1 to 3).

[0367] Preferred dienes can be listed as:

[0368] CH2=CH-(CF2)2-CH=CH2、

[0369] CH2=CH-(CF2)4-CH=CH2、

[0370] CH2=CH-(CF2)6-CH=CH2、

[0371] Formula: CH2=CH-Z 1 -CH=CH2

[0372] (where Z) 1 It is -CH2OCH2-CF2O-(CF2CF2O) m -(CF2O) n -CF2-CH2OCH2- (m / n is 0.5), molecular weight preferably 2000, etc.

[0373] Preferably, it is 3,3,4,4,5,5,6,6,7,7,8,8-dodecano-1,9-decadiene as shown in CH2=CH-(CF2)6-CH=CH2.

[0374] The number-average molecular weight Mn of the fluorinated elastomer is preferably 1,000 to 1,000,000, more preferably 10,000 to 500,000, and particularly preferably 20,000 to 300,000.

[0375] The fluorine content of the fluorinated elastomer is preferably 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, more preferably 73% by mass or less. The fluorine content is based on... 19 F-NMR and1 The values ​​are calculated from measurements obtained by H-NMR, elemental analysis, etc.

[0376] The Mooney viscosity (ML1+10(100°C)) of the fluorinated elastomer at 100°C is preferably 130 or less. More preferably, it is 110 or less, and even more preferably 90 or less. Furthermore, it is more preferably 10 or more, and even more preferably 20 or more. Here, the Mooney viscosity is a value measured according to JIS K 6300-1.2013.

[0377] The glass transition temperature of the fluorinated elastomer is preferably -50°C to 0°C. More preferably, it is below -2°C, and even more preferably below -3°C. Furthermore, it is more preferably above -45°C, and even more preferably above -40°C. The glass transition temperature can be above -10°C or above, or above -9°C. Here, the glass transition temperature can be determined as follows: using a differential scanning calorimeter (e.g., Hitachi High-Tech Science X-DSC7000), a DSC curve is obtained by heating 10 mg of the sample at 20°C / min. According to JIS K 6240:2011, the glass transition temperature can be determined from the DSC differential curve.

[0378] The iodine content of the fluorinated elastomer is preferably 0.05% to 1.0% by mass. More preferably, the iodine content is 0.08% by mass or more, even more preferably 0.10% by mass or more, and even more preferably 0.8% by mass or less, even more preferably 0.60% by mass or less.

[0379] Iodine content can be determined through elemental analysis. Specifically, 5 mg of Na₂SO₃ is mixed with 12 mg of fluorinated elastomer, and 30 mg of a substance prepared by mixing Na₂CO₃ and K₂CO₃ in a 1:1 mass ratio is dissolved in 20 ml of pure water to obtain an absorption solution. This absorption solution is then burned in oxygen in a quartz flask. After standing for 30 minutes, the iodine content can be determined using a Shimadzu 20A ion chromatograph. As calibration curves, KI standard solution, a solution containing 0.5 ppm iodine ions, and a solution containing 1.0 ppm iodine ions can be used.

[0380] Fluorinated elastomers preferably contain a -CH2I structure. This can be achieved through... 1 ¹H-NMR spectroscopy confirmed the presence of the -CH₂I structure. Fluorinated elastomers containing the -CH₂I structure can be obtained through iodine transfer polymerization.

[0381] The fluorinated elastomer preferably contains 0.05 mol% to 1.50 mol% of the -CH2I structure relative to 100 mol% of the -CH2- structure. More preferably, the amount of the -CH2I structure is 0.08 mol% or more, further preferably 0.12 mol% or more, more preferably 1.20 mol% or less, further preferably 1.00 mol% or less, and particularly preferably 0.80 mol% or less. The amount of the -CH2I structure can be determined by... 1 The H-NMR spectrum was obtained.

[0382] Fluorinated elastomers are further preferably those containing the -CF2CH2I structure. Fluorinated elastomers containing the -CF2CH2I structure can be obtained by using iodine transfer polymerization to produce VdF-based fluorinated elastomers.

[0383] The fluorinated elastomer preferably contains 0.05 mol% to 1.50 mol% of the -CF2CH2I structure relative to 100 mol% of the -CH2- structure. The amount of the -CF2CH2I structure is more preferably 0.08 mol% or more, further preferably 0.12 mol% or more, more preferably 1.20 mol% or less, further preferably 1.00 mol% or less, and particularly preferably 0.80 mol% or less. The amount of the -CF2CH2I structure is calculated by A / B*100 from the integral value A of all peak intensities and the integral value B of all peak intensities. The integral value A of all peak intensities is... 1 The integral value of all peak intensities observed in the H-NMR spectrum in the region from -CH2I with a chemical shift of 3.75 ppm to 4.05 ppm, and the integral value B of all peak intensities observed in the regions from -CH2- with chemical shifts of 2.3 ppm to 2.7 ppm and 2.9 ppm to 3.75 ppm.

[0384] As the fluorinated monomer used in the manufacturing method of the present invention, the fluorinated monomer described for fluorinated elastomers may be used appropriately.

[0385] In the manufacturing method of the present invention, starting from the ability to further suppress the adhesion of fluorinated elastomers to the polymerization tank and simultaneously produce a larger quantity of fluorinated elastomer particles at a higher polymerization rate, the fluorinated monomers can be further polymerized in the presence of a fluorinated compound (A) (excluding compound (1)) containing functional groups and hydrophilic groups capable of undergoing free radical polymerization. In the manufacturing method of the present invention, one or more fluorinated compounds (A) can be used. Alternatively, in the manufacturing method of the present invention, the fluorinated monomers can be polymerized in the absence of fluorinated compound (A) (excluding compound (1)). According to the manufacturing method of the present invention, even when the fluorinated monomers are polymerized in the absence of fluorinated compound (A), the adhesion of fluorinated elastomers to the polymerization tank can be suppressed, and a sufficient quantity of fluorinated elastomer particles can be produced at a sufficient polymerization rate.

[0386] The fluorinated compound (A) is preferably a compound containing anionic or nonionic hydrophilic groups, and more preferably a compound containing anionic hydrophilic groups. The fluorinated compound (A) may contain only anionic hydrophilic groups or only nonionic hydrophilic groups. Furthermore, as the fluorinated compound (A), a compound containing only anionic hydrophilic groups, a compound containing only nonionic hydrophilic groups, or a combination of both can be used.

[0387] Examples of hydrophilic groups in fluorinated compounds (A) include -NH2, -P(O)(OM)2, -OP(O)(OM)2, -SO3M, -OSO3M, -COOM, -B(OM)2, and -OB(OM)2 (where M represents H, a metal atom, or NR). 7 4. Imidazolium with or without substituents, pyridinium with or without substituents, or phosphonium with or without substituents, R 7 It can be H or an organic group, which can be the same or different. Any two can bond together to form a ring. As the above-mentioned hydrophilic group, -SO3M or -COOM is preferred, and -COOM is more preferred. As R 7 The organic group, preferably alkyl. As R 7 H or C are preferred 1-10 Organic groups, more preferably H or C 1-4 The organic groups, preferably H or C, are preferred. 1-4 Alkyl groups, preferably H. In formulas containing two M atoms, the two M atoms may be the same or different. As metal atoms, monovalent or divalent metal atoms can be mentioned, including alkali metals (Group 1) or alkaline earth metals (Group 2), more preferably Na, K, or Li.

[0388] As a "functional group capable of undergoing free radical polymerization" in fluorinated compound (A), a group containing a free radical polymerizable unsaturated bond can be cited.

[0389] Examples of groups possessing free radical polymerizability and unsaturated bonds include vinyl and allyl groups, which possess olefinic unsaturated bonds. Groups possessing olefinic unsaturated bonds can be represented by the following formula:

[0390] CX e X g =CX f R-

[0391] (where X) e X f and X gEach can be independently represented as F, Cl, H, CF3, CF2H, CFH2, or CH3; R is a linking group. Examples of linking groups for R, as described below, are... a The linking group.

[0392] Examples of groups with free radical polymerizability and unsaturated bonds include -CH=CH2, -CF=CH2, -CH=CF2, -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.

[0393] Since fluorinated compound (A) possesses functional groups capable of undergoing free radical polymerization, it is speculated that if used in the above polymerization, it will react with the fluorinated monomer and compound (1) in the early stages of the polymerization reaction, possessing hydrophilic groups from both compound (1) and fluorinated compound (A), thus forming highly stable particles. Therefore, it is believed that if polymerization is carried out in the presence of compound (1) and fluorinated compound (A), the number of fluorinated elastomer particles produced during polymerization will increase.

[0394] In the manufacturing method of the present invention, starting from the ability to further suppress the adhesion of fluorinated elastomers to the polymerization tank and at the same time generate a larger amount of fluorinated elastomer particles at a higher polymerization rate, the fluorinated monomers can be further polymerized in the presence of the fluorinated compound (A) shown in general formula (A).

[0395] General formula (A): CX i X k =CX j R a -(CZ 1 Z 2 ) k -Y 3

[0396] (where X) i X j and X k Each can be independently F, Cl, H or CF3;

[0397] Y 3 R is a hydrophilic group; a Z is a linking group;1 and Z 2 Each is independently H, F, or CF3; k is 0 or 1. Where X i X k X j R a Z 1 and Z 2 At least one of them contains F. Where, when k is 0, R a (A linking group other than a single bond.)

[0398] Y in general formula (A) 3 It is a hydrophilic group. As a hydrophilic group, for example, from the perspective of further suppressing the adhesion of fluorinated elastomers to the polymerization tank while producing a larger amount of fluorinated elastomer particles at a higher polymerization rate, the preferred hydrophilic groups are -NH2, -P(O)(OM)2, -OP(O)(OM)2, -SO3M, -OSO3M, -COOM, -B(OM)2, and -OB(OM)2 (where M is H, a metal atom, or NR). 7 4. Imidazolium with or without substituents, pyridinium with or without substituents, or phosphonium with or without substituents, R 7 It can be H or an organic group, which can be the same or different. Any two can bond together to form a ring. As the above-mentioned hydrophilic group, -SO3M or -COOM is more preferred, and -COOM is even more preferred. As R 7 The organic group, preferably alkyl. As R 7 H or C are preferred 1-10 Organic groups, more preferably H or C 1-4 The organic groups, preferably H or C, are preferred. 1-4 Alkyl groups, with H being the most preferred. As for the metal atom, monovalent or divalent metal atoms can be cited, with alkali metals (Group 1) or alkaline earth metals (Group 2) being preferred, and Na, K, or Li being more preferred.

[0399] R in general formula (A) a The linking group is a divalent linking group. Preferably, it is a single bond or a group containing at least one carbon atom. Wherein, when k is 0, R... a The linking group is a group other than a single bond, preferably a group containing at least one carbon atom. The number of carbon atoms in the linking group can 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; for example, it can be less than 100 or less than 50.

[0400] The linking group can be chain-like or branched, cyclic or acyclic, saturated or unsaturated, substituted or unsubstituted, and may contain one or more heteroatoms selected from the group consisting of sulfur, oxygen, and nitrogen, and may contain one or more functional groups selected from the group consisting of esters, amides, sulfonamides, carbonyl groups, carbonates, carbamates, ureas, and carbamates. The linking group does not contain a carbon atom and may be a chain-like heteroatom such as oxygen, sulfur, or nitrogen.

[0401] R a Preferably, it consists of chain heteroatoms such as oxygen, sulfur, and nitrogen, or divalent organic groups.

[0402] R a In the case of a divalent organic group, the hydrogen atom bonded to the carbon atom can be replaced by a halogen other than fluorine, such as chlorine, and may or may not contain a double bond. Additionally, R... a It can be either chain-like or branched, or cyclic and acyclic. Additionally, R... a It may contain functional groups (such as esters, ethers, ketones, amines, halides, etc.).

[0403] Additionally, R a It can be a non-fluorinated divalent organic group, or a partially fluorinated or perfluorinated divalent organic group.

[0404] As R a For example, a hydrocarbon group with no fluorine atom bonded to the carbon atom; a hydrocarbon group with some of the hydrogen atoms bonded to the carbon atom replaced by fluorine atoms; a hydrocarbon group with all the hydrogen atoms bonded to the carbon atom replaced by fluorine atoms; a hydrocarbon group containing -(C=O)-, -(C=O)-O- or ether bonds; which may contain oxygen atoms, double bonds, or functional groups.

[0405] R a Preferably, it is a hydrocarbon group with 1 to 100 carbon atoms, containing or not containing -(C=O)-, -(C=O)-O- or ether bonds, and containing or not containing a carbonyl group, wherein some or all of the hydrogen atoms bonded to the carbon atoms in the hydrocarbon group can be replaced by fluorine.

[0406] As R a Preferably, the free radical is selected from -(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 -, -(C=O)-O-C6H4-, and at least one of their combinations.

[0407] In the formula, a, b, c, and d are each at least 1. a, b, c, and d can each be 2 or higher, 3 or higher, 4 or higher, 10 or higher, or 20 or higher. The upper limit for a, b, c, and d is, for example, 100.

[0408] As R a Preferred specific examples include -CF2-O-, -CF2-O-CF2-, -CF2-O-CH2-, -CF2-O-CH2CF2-, -CF2-O-CF2CF2-, -CF2-O-CF2CH2-, -CF2-O-CF2CF2CH2-, -CF2-O-CF2CF2CH2-, -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)-, and -(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. Among them, as R a , preferably -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-.

[0409] In the above formula, n is an integer from 1 to 10.

[0410] As -R in the general formula (A) a -(CZ 1 Z 2 ) k -, preferably -CF2-O-CF2-, -CF2-O-CF(CF3)-, -CF2-O-C(CF3)2-, -CF2-O-CF2-CF2-, -CF2-O-CF2-CF(CF3)-, -CF2-O-CF2-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-, -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-O-C(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-, more preferably -CF2-O-CF(CF3)-, -CF2-O-CF2-CF(CF3)-, -CF2-O-CF2CF2-CF(CF3)-, -CF2-O-CF(CF3)-CF(CF3)-, -CF2-O-CF(CF 3)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-.

[0411] In the above formula, n is an integer from 1 to 10.

[0412] As specific examples of compounds represented by general formula (A), the following can be cited:

[0413] [Chemistry 15]

[0414]

[0415] (where X) j and Y 3 Same as above. (n is an integer from 1 to 10), etc.

[0416] As R a Preferably, the divalent group represented by the following general formula (r1) is preferred.

[0417] -(C=O) h -(O) i -CF2-O-(CX 6 2) e -{O-CF(CF3)} f -(O) g -(r1)

[0418] (where X) 6Each of the following is independently H, F, or CF3, where e is an integer from 0 to 3, f is an integer from 0 to 3, g is 0 or 1, h is 0 or 1, and i is 0 or 1.

[0419] The divalent group shown in the following general formula (r2) is also preferred.

[0420] -(C=O) h -(O) i -CF2-O-(CX 7 2) e -(O) g -(r2)

[0421] (where X) 7 Each of these can be independently H, F, or CF3, e is an integer from 0 to 3, g is 0 or 1, h is 0 or 1, and i is 0 or 1.

[0422] Additionally, -R as a general formula (A) a -(CZ 1 Z 2 ) k - It is also preferable to use the following formula (t1):

[0423] -(C=O) h -(O) i -CF2-O-(CX 6 2) e -{O-CF(CF3)} f -(O) g -CZ 1 Z 2 -(t1)

[0424] (where X) 6 Each is independently H, F, or CF3, e is an integer from 0 to 3, f is an integer from 0 to 3, g is 0 or 1, h is 0 or 1, i is 0 or 1, Z is 0 or 1. 1 and Z 2 Each is an independent divalent group represented by F or CF3), in formula (t1), Z 1 and Z 2 One of them is F, and the other is CF3.

[0425] Furthermore, in the above general formula (A), -R a -(CZ 1 Z 2 ) k - It is also preferable to use the following formula (t2):

[0426] -(C=O) h -(O) i -CF2-O-(CX 7 2) e-(O) g -CZ 1 Z 2 -(t2)

[0427] (where X) 7 Each is independently H, F, or CF3, e is an integer from 0 to 3, g is 0 or 1, h is 0 or 1, i is 0 or 1, and Z is 0 or 1. 1 and Z 2 Each is an independent divalent group represented by F or CF3), in formula (t2), Z 1 and Z 2 One of them is F, and the other is CF3.

[0428] The compound represented by general formula (A) is also preferably in the absence of the hydrophilic group (Y). 3 The portion other than X has CF bonds and no CH bonds. That is, in general formula (A), X is preferred. i X j and X k All are F, R a It is a perfluoroalkylene group having 1 or more carbon atoms. The perfluoroalkylene group can be either chain-like or branched, cyclic or acyclic, and can contain at least one chain heteroatom. The number of carbon atoms in the perfluoroalkylene group can be 2 to 20, or 4 to 18.

[0429] The compound represented by general formula (A) can also be partially fluorinated. That is, the compound represented by general formula (A) is also preferably fluorinated in the absence of the hydrophilic group (Y). 3 The portion other than ) has at least one hydrogen atom bonded to a carbon atom and at least one fluorine atom bonded to a carbon atom.

[0430] The compound represented by general formula (A) is also preferably the compound represented by the following formula (Aa).

[0431] CF2 = CF-O-Rf 0 -Y 3 (Aa)

[0432] (where Y) 3 Rf is a hydrophilic group. 0 Perfluorinated compounds can be chain-like or branched, cyclic or acyclic, saturated or unsaturated, substituted or unsubstituted, and can arbitrarily contain one or more heteroatoms selected from the group consisting of sulfur, oxygen, and nitrogen as a perfluorinated divalent linking group.

[0433] The compound represented by general formula (A) is also preferably the compound represented by the following formula (Ab).

[0434] CH2=CH-O-Rf 0 -Y 3(Ab)

[0435] (where Y) 3 Rf is a hydrophilic group. 0 (Aa) is the perfluorinated divalent linker as defined in formula (Aa).

[0436] In general formula (A), Y 3 -OSO3M is one of the preferred methods. In Y 3 In the case of -OSO3M, examples of compounds represented by general formula (A) 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(OCF2CF2SO2N(CH3)CH2CH2OSO3M), CH2=CH(CF2CF2CH2OSO3M), CF2=CF(OCF2CF2CF2CF2SO2N(CH3)CH2CH2OSO3M), and CH2=CH(CF2CF2CH2OSO3M). In the above formulas, M is the same as described above.

[0437] In general formula (A), Y 3 -SO3M is also one of the preferred methods. In Y 3 In the case of -SO3M, examples of compounds represented by general formula (A) 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 formula, M is the same as described above.

[0438] In general formula (A), Y 3 Using -COOM is also a preferred method. In Y 3In the case of -COOM, examples of compounds represented by general formula (A) include CF2=CF(OCF2CF2COOM), CF2=CF(OCF2CF2CF2COOM), CF2=CF(O(CF2)5COOM), CF2=CF(OCF2CF(CF3)COOM), and 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)O CF2CF2SO2NR'CH2COOM), CH2=CH(CF2CF2SO2NR'CH2COOM), CF2=CF(OCF2CF(CF3)OCF2CF2CF2CF2SO2NR'CH2C OOM), CH2=CH((CF2)4SO2NR'CH2COOM), CH2=CH(CF2CF2SO2NR'CH2COOM), CH2=CH((CF2)3SO2NR'CH2COOM), etc. In the above formula, R' is H or C 1-4 Alkyl groups, M is the same as above.

[0439] In general formula (A), Y 3 -OP(O)(OM)2 is also a preferred option. In Y 3 In the case of -OP(O)(OM)2, as compounds represented by general formula (A), examples 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 Formulas such as 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 formulas, M is the same as described above.

[0440] In general formula (A), Y 3 -P(O)(OM)2 is also a preferred option. In Y 3 In the case of -P(O)(OM)2, examples of compounds represented by general formula (A) 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), etc., where M is the same as above.

[0441] The compound represented by general formula (A) is preferably at least one selected from the group consisting of general formula (5):

[0442] CX2=CY(-CZ2-O-Rf-Y 3 (5)

[0443] (In the formula, X may be the same or different and is -H or -F; Y may be -H, -F, alkyl or fluoroalkyl; Z may be the same or different and is -H, -F, alkyl or fluoroalkyl. Rf is a fluoroalkylene group with 1 to 40 carbon atoms, or a fluoroalkylene group with ether bonds with 2 to 100 carbon atoms. Y) 3 Compounds as shown above; general formula (6):

[0444] CX2=CY(-O-Rf-Y 3 (6)

[0445] (In the formula, X may be the same or different, and can be -H or -F; Y can be -H, -F, alkyl or fluorinated alkyl; Rf is a fluorinated alkylene with 1 to 40 carbon atoms, or a fluorinated alkylene with ether bonds having 2 to 100 carbon atoms. Y) 3 Compounds as shown above; and general formula (7):

[0446] CX2 = CY(-Rf-Y) 3 (7)

[0447] (In the formula, X may be the same or different, and can be -H or -F; Y can be -H, -F, alkyl or fluorinated alkyl; Rf is a fluorinated alkylene with 1 to 40 carbon atoms, or a fluorinated alkylene with ether bonds having 2 to 100 carbon atoms. Y) 3 The same compound as described above.

[0448] It should be noted that the fluorinated alkylene groups with ether bonds having 2 to 100 carbon atoms mentioned above are alkylene groups that do not have oxygen atoms at the end but contain ether bonds between carbon atoms.

[0449] In general formula (5), X is -H or -F. X can be both -F or at least one -H. For example, one can be -F and the other -H, or both can be -H.

[0450] In general formula (5), Y is -H, -F, alkyl, or fluorinated alkyl. The alkyl group is an alkyl group without fluorine atoms, and has 1 or more carbon atoms. The alkyl group preferably has 6 or fewer carbon atoms, more preferably 4 or fewer, and even more preferably 3 or fewer. The fluorinated alkyl group is an alkyl group containing at least one fluorine atom, and has 1 or more carbon atoms. The fluorinated alkyl group preferably has 6 or fewer carbon atoms, more preferably 4 or fewer, and even more preferably 3 or fewer. Y is preferably -H, -F, or -CF3, more preferably -F.

[0451] In general formula (5), Z can be the same or different, and can be -H, -F, alkyl, or fluoroalkyl. The alkyl group is an alkyl group that does not contain fluorine atoms, and has 1 or more carbon atoms. The number of carbon atoms in the alkyl group is preferably 6 or less, more preferably 4 or less, and even more preferably 3 or less. The fluoroalkyl group is an alkyl group containing at least one fluorine atom, and has 1 or more carbon atoms. The number of carbon atoms in the fluoroalkyl group is preferably 6 or less, more preferably 4 or less, and even more preferably 3 or less. Z is preferably -H, -F, or -CF3, more preferably -F.

[0452] In general formula (5), at least one of X, Y and Z preferably contains a fluorine atom. For example, X can be -H and Y and Z can be -F.

[0453] In general formula (5), Rf is a fluorinated alkylene group having 1 to 40 carbon atoms, or a fluorinated alkylene group having an ether bond having 2 to 100 carbon atoms. The fluorinated alkylene group preferably has 2 or more carbon atoms. Furthermore, the fluorinated alkylene group preferably has 30 or fewer carbon atoms, more preferably 20 or fewer, and even more preferably 10 or fewer. Examples of the fluorinated alkylene group include -CF2-, -CH2CF2-, -CF2CF2-, -CF2CH2-, -CF2CF2CH2-, -CF(CF3)-, -CF(CF3)CF2-, and -CF(CF3)CH2-. The fluorinated alkylene group is preferably a perfluoroalkylene group.

[0454] The fluorinated alkylene group having an ether bond preferably has 3 or more carbon atoms. Furthermore, the fluorinated alkylene group having an ether bond preferably has 60 or fewer carbon atoms, more preferably 30 or fewer, and even more preferably 12 or fewer.

[0455] As a fluorinated alkylene group having an ether bond, the following formula is also preferred, for example:

[0456] [Chemistry 16]

[0457]

[0458] (where Z) 1 For F or CF3; Z 2 and Z 3 H or F respectively; Z 4 The divalent group is H, F or CF3; p1+q1+r1 is an integer from 1 to 10; s1 is 0 or 1; t1 is an integer from 0 to 5.

[0459] As fluorinated alkylene groups with ether bonds, examples include -CF(CF3)CF2-O-CF(CF3)- and -(CF(CF3)CF2-O). n -CF(CF3)- (where n is an integer from 1 to 10), -CF(CF3)CF2-O-CF(CF3)CH2-, -(CF(CF3)CF2-O) n -CF(CF3)CH2- (where n is an integer from 1 to 10), -CH2CF2CF2O-CH2CF2CH2-, -CF2CF2CF2O-CF2CF2-, -CF2CF2CF2O-CF2CF2CH2-, -CF2CF2O-CF2-, -CF2CF2O-CF2-, -CF2CF2O-CF2CH2-, etc. The fluorinated alkylene groups with ether bonds mentioned above are preferably perfluoroalkylene groups.

[0460] In general formula (5), Y 3 Preferably -COOM, -SO3M, or -OSO3M (M is H, a metal atom, or NR). 7 4. Imidazolium with or without substituents, pyridinium with or without substituents, or phosphonium with or without substituents, R 7 It can be an H group or an organic group, which can be the same or different. Any two can bond together to form a ring.

[0461] As R 7 The organic group, preferably alkyl. As R 7 H or C are preferred 1-10 Organic groups, more preferably H or C 1-4 The organic groups, preferably H or C, are preferred. 1-4 Alkyl groups. Examples of metal atoms include alkali metals (Group 1) and alkaline earth metals (Group 2), with Na, K, or Li being preferred. As the M atom, -H, a metal atom, or -NR are preferred. 7 4. More preferably -H, alkali metal (Group 1), alkaline earth metal (Group 2) or -NR7 4. Further preferred are -H, -Na, -K, -Li or -NH4, more preferably -Na, -K or -NH4, particularly preferably -Na or -NH4, and most preferably -NH4. As Y 3 Preferably -COOM or -SO3M, more preferably -COOM.

[0462] The compound represented by general formula (5) is preferably the compound represented by general formula (5a).

[0463] CH2=CF(-CF2-O-Rf-Y 3 (5a)

[0464] (where Rf and Y are in the formula) 3 Same as above.

[0465] Specifically, as a compound represented by general formula (5a), the following formula can be cited:

[0466] [Chemistry 17]

[0467]

[0468] (where Z) 1 For F or CF3; Z 2 and Z 3 H or F respectively; Z 4 For H, F, or CF3; p1+q1+r1 is an integer from 0 to 10; s1 is 0 or 1; t1 is an integer from 0 to 5, Y 3 Same as above. Wherein, Z 3 and Z 4 The compounds shown (where p1+q1+r1+s1 is not 0 when all are H) are preferred. More specifically, examples of preferred compounds include...

[0469] [Chemistry 18]

[0470]

[0471] CH2=CFCF2OCH2CF2-Y 3 , cH2=CFCF2O(CH2CF2CF2O)CH2CF2-Y 3 ,

[0472] CH2=CFCF2OCH2CF2CH2-Y 3 ,

[0473] CH2=CFCF2O(CH2CF2CF2O)CH2CF2CH2-Y 3 ,

[0474] CH2=CFCF2OCF2CF2-Y3 , CH2=CFCF2O(CF2CF2CF2O)CF2CF2-Y 3 ,

[0475] CH2=CFCF2OCF2CF2CH2-Y 3 ,

[0476] CH2=CFCF2O(CF2CF2CF2O)CF2CF2CH2-Y 3 ,

[0477] CH2=CFCF2oCF2-Y 3 CH2=CFCF2O(CF2CF2O)CF2-Y 3 ,

[0478] CH2=CFCF2OCF2CH2-Y 3 ,

[0479] CH2=CFCF2O(CF2CF2o)CF2CH2-Y 3 ,

[0480] etc., among which the preferred option is

[0481] [Chemistry 19]

[0482]

[0483] As a compound represented by general formula (5a), Y in preferred formula (5a) 3 For -COOM, it is particularly preferred to select at least one of the group consisting of CH2=CFCF2OCF(CF3)COOM and CH2=CFCF2OCF(CF3)CF2OCF(CF3)COOM (where M is the same as defined above), and more preferably CH2=CFCF2OCF(CF3)COOM.

[0484] The compound represented by general formula (5) is preferably the compound represented by general formula (5b).

[0485] CX 2 2=CFCF2-O-(CF(CF3)CF2O) n5 -CF(CF3)-Y 3 (5b)

[0486] (In the formula, each X) 2 Same, indicating F or H. n5 represents 0 or an integer from 1 to 10, Y 3 Same as the definition above.

[0487] In general formula (5b), from the perspective of the stability of the obtained aqueous dispersion, n5 is preferably an integer from 0 or 1 to 5, more preferably 0, 1 or 2, and even more preferably 0 or 1. From the perspective of obtaining moderate water solubility and stability of the aqueous dispersion, Y 3 M is preferably -COOM, and from the perspective of being less likely to remain as an impurity and improving the heat resistance of the obtained molded article, M is preferably H or NH4.

[0488] Examples of compounds represented by general formula (5b) include CH2=CFCF2OCF(CF3)COOM and CH2=CFCF2OCF(CF3)CF2OCF(CF3)COOM (where M is the same as defined above).

[0489] In addition, as compounds represented by general formula (5), compounds represented by general formula (5c) and the like can also be cited.

[0490] CF2 = CFCF2-O-Rf-Y 3 (5c)

[0491] (where Rf and Y are in the formula) 3 Same as above.

[0492] More specifically, examples can be given.

[0493] [Chemistry 20]

[0494] CF2 = CFCF2OCF2CF2CF2-Y 3 ,

[0495]

[0496] CF2=CFCF2OCF2CF2CF2CH2-Y 3 ,

[0497] wait.

[0498] In general formula (6), X is -H or -F. X can be -F for both, or at least one of them can be -H. For example, one can be -F and the other can be -H, or both can be -H.

[0499] In general formula (6), Y is -H, -F, alkyl, or fluorinated alkyl. The alkyl group is an alkyl group without fluorine atoms, and has 1 or more carbon atoms. The alkyl group preferably has 6 or fewer carbon atoms, more preferably 4 or fewer, and even more preferably 3 or fewer. The fluorinated alkyl group is an alkyl group containing at least one fluorine atom, and has 1 or more carbon atoms. The fluorinated alkyl group preferably has 6 or fewer carbon atoms, more preferably 4 or fewer, and even more preferably 3 or fewer. Y is preferably -H, -F, or -CF3, more preferably -F.

[0500] In general formula (6), at least one of X and Y preferably contains a fluorine atom. For example, X can be -H, and Y and Z can be -F.

[0501] In general formula (6), Rf is a fluorinated alkylene group having 1 to 40 carbon atoms, or a fluorinated alkylene group having 2 to 100 carbon atoms and having an ether bond. The fluorinated alkylene group preferably has 2 or more carbon atoms. Furthermore, the fluorinated alkylene group preferably has 30 or fewer carbon atoms, more preferably 20 or fewer, and even more preferably 10 or fewer. Examples of fluorinated alkylene groups include -CF2-, -CH2CF2-, -CF2CF2-, -CF2CH2-, -CF2CF2CH2-, -CF(CF3)-, -CF(CF3)CF2-, and -CF(CF3)CH2-. The fluorinated alkylene group is preferably a perfluoroalkylene group.

[0502] In the above general formula (6), Y 3 Preferably -COOM, -SO3M, or -OSO3M (M is H, a metal atom, or NR). 7 4. Imidazolium with or without substituents, pyridinium with or without substituents, or phosphonium with or without substituents, R 7 It can be an H group or an organic group, which can be the same or different. Any two can bond together to form a ring.

[0503] As R 7 The organic group, preferably alkyl. As R 7 H or C are preferred 1-10 Organic groups, more preferably H or C 1-4 The organic groups, preferably H or C, are preferred. 1-4 Alkyl groups. Examples of metal atoms mentioned above include alkali metals (Group 1) and alkaline earth metals (Group 2), with Na, K, or Li being preferred. As for M, -H, a metal atom, or -NR are preferred. 7 4. More preferably -H, alkali metal (Group 1), alkaline earth metal (Group 2) or -NR 7 4. Further preferred are -H, -Na, -K, -Li or -NH4, more preferably -Na, -K or -NH4, particularly preferably -Na or -NH4, and most preferably -NH4. As described above, Y... 3 Preferably -COOM or -SO3M, more preferably -COOM.

[0504] The compound represented by general formula (6) is preferably selected from at least one of the groups consisting of compounds represented by general formulas (6a) to (6f).

[0505] CF2 = CF - O - (CF2) n1 -Y 3 (6a)

[0506] (In the formula, n1 represents an integer from 1 to 10, and Y3 is defined the same as above.)

[0507] CF2=CF-O-(CF2C(CF3)F) n2 -Y 3 (6b)

[0508] (In the formula, n2 represents an integer from 1 to 5, Y) 3 Same as the definition above.

[0509] CF2 = CF-O-(CFX) 1 ) n3 -Y 3 (6c)

[0510] (where X) 1 Let F or CF3 represent n3, where n3 represents an integer from 1 to 10, and Y represents n3. 3 Same as the definition above.

[0511] CF2 = CF-O-(CF2CFX) 1 O) n4 -(CF2) n6 -Y 3 (6d)

[0512] (In the formula, n4 represents an integer from 1 to 10, n6 represents an integer from 1 to 3, Y) 3 and X 1 Same as the definition above.

[0513] CF2 = CF-O - (CF2CF2CFX) 1 O) n5 -CF2CF2CF2-Y 3 (6e)

[0514] (In the formula, n5 represents an integer from 0 to 10, Y) 3 and X 1 Same as the definition above.

[0515] CF2 = CF - O(-CF2) n6 -O-CF2-Y 3 (6f)

[0516] (In the formula, n6 represents an integer from 1 to 6, Y) 3 and X 1 Same as the definition above.

[0517] In general formula (6a), n1 is preferably an integer of 5 or less, more preferably an integer of 2 or less. From the perspective of obtaining moderate water solubility and stability of the aqueous dispersion, Y 3The preferred form is -COOM or -SO3M. For ease of synthesis, M is preferably Na, H or NH4. For the purpose of minimizing the residue as an impurity and improving the heat resistance of the resulting molded product, M is preferably H or NH4.

[0518] 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) (where M is defined as above).

[0519] In general formula (6b), from the perspective of the stability of the obtained aqueous dispersion, n2 is preferably an integer of 3 or less; from the perspective of obtaining moderate water solubility and stability of the aqueous dispersion, Y 3 The preferred form is -COOM or -SO3M. From the perspective of minimizing the residue as an impurity and improving the heat resistance of the resulting molded article, M is preferably H or NH4.

[0520] In general formula (6c), from the perspective of water solubility, n3 is preferably an integer of 5 or less; from the perspective of obtaining moderate water solubility and stability of the aqueous dispersion, Y 3 Preferably, it is -COOM or -SO3M. From the perspective of improving dispersion stability, M is preferably H, Na or NH4.

[0521] In general formula (6d), from the perspective of the stability of aqueous dispersions, X 1 Preferably -CF3, from the perspective of water solubility, n4 is preferably an integer of 5 or less, and from the perspective of obtaining moderate water solubility and stability of the aqueous dispersion, Y 3 Preferably, it is -COOM or -SO3M, where M is preferably H, Na or NH4.

[0522] Examples of compounds represented by the general formula (6d) include CF2=CFOCF2CF(CF3)OCF2CF2COOM, CF2=CFOCF2CF(CF3)OCF2COOM, CF2=CFOCF2CF(CF3)OCF2CF2CF2COOM, CF2=CFOCF2CF(CF3)OCF2SO3M, CF2=CFOCF2CF(CF3)OCF2CF2SO3M, and CF2=CFOCF2CF(CF3)OCF2CF2CF2SO3M (where M represents H, NH4, or an alkali metal).

[0523] In general formula (6e), from the perspective of water solubility, n5 is preferably an integer of 5 or less; from the perspective of obtaining moderate water solubility and stability of the aqueous dispersion, Y 3 Preferably -COOM, and M is preferably H, Na or NH4.

[0524] Examples of compounds represented by the general formula (6e) include CF2=CFOCF2CF2CF2COOM (where M represents H, NH4 or an alkali metal).

[0525] Examples of compounds represented by the general formula (6f) include CF2=CFOCF2CF2CF2OCF2COOM (where M represents H, NH4 or an alkali metal).

[0526] In general formula (7), Rf is preferably a fluorinated alkylene group having 1 to 40 carbon atoms. In general formula (7), at least one of X and Y preferably contains a fluorine atom.

[0527] The compound represented by general formula (7) is preferably selected from general formula (7a):

[0528] CF2 = CF - (CF2) n1 -Y 3 (7a)

[0529] (In the formula, n1 represents an integer from 1 to 10, Y) 3 The compounds shown in the above definition, and the general formula (7b):

[0530] CF2 = CF - (CF2C(CF3)F) n2 -Y 3 (7b)

[0531] (In the formula, n2 represents an integer from 1 to 5, Y) 3 At least one of the groups consisting of compounds as defined above.

[0532] Y in general formula (7) 3 Preferred options are -SO3M or -COOM, where M is preferably H, a metal atom, or NR. 7 4. Imidazolium with or without substituents, pyridinium with or without substituents, or phosphatonium with or without substituents. R 7 It represents H or an organic group.

[0533] In general formula (7a), n1 is preferably an integer of 5 or less, more preferably an integer of 2 or less. From the perspective of obtaining moderate water solubility and stability of the aqueous dispersion, Y 3 M is preferably -COOM, and from the perspective of being less likely to remain as an impurity and improving the heat resistance of the obtained molded article, M is preferably H or NH4.

[0534] Examples of compounds represented by general formula (7a) include CF2=CFCF2COOM (where M is defined as above).

[0535] In general formula (7b), from the perspective of the stability of the obtained aqueous dispersion, n2 is preferably an integer of 3 or less; from the perspective of obtaining moderate water solubility and stability of the aqueous dispersion, Y 3 M is preferably -COOM, and from the perspective of being less likely to remain as an impurity and improving the heat resistance of the obtained molded article, M is preferably H or NH4.

[0536] As the fluorinated compound (A), it is preferably selected from at least one of the group consisting of the compound shown in general formula (5), the compound shown in general formula (6) and the compound shown in general formula (7), more preferably selected from at least one of the group consisting of the compound shown in general formula (5) and the compound shown in general formula (6), and even more preferably the compound shown in general formula (5).

[0537] Furthermore, the compound represented by general formula (5) is preferably selected from at least one of the group consisting of the compound represented by general formula (5a), the compound represented by general formula (5b), and the compound represented by general formula (5c). More preferably, at least one of the group consisting of the compound represented by general formula (5a) and the compound represented by general formula (5b) is selected, and the compound represented by general formula (5a) is even more preferred.

[0538] In the polymerization of fluorinated monomers, the amount of fluorinated compound (A) relative to the aqueous medium is preferably 3 to 5000 ppm by mass, more preferably 5 ppm or more, further preferably 10 ppm or more, particularly preferably 20 ppm or more, most preferably 30 ppm or more, and more preferably 1000 ppm or less, further preferably 500 ppm or less, particularly preferably 200 ppm or less, and most preferably 100 ppm or less.

[0539] It is also preferable to adjust the amount of fluorinated compound (A) according to the type of polymerization initiator used in the polymerization and the polymerization temperature.

[0540] When using a non-redox polymerization initiator as the polymerization initiator and performing polymerization at 40°C to 70°C, the amount of fluorinated compound (A) relative to the aqueous medium is preferably 3 ppm to 300 ppm by mass, more preferably 3 ppm to 150 ppm by mass, further preferably 5 ppm to 100 ppm by mass, and most preferably 8 ppm to 80 ppm by mass.

[0541] When using a non-redox polymerization initiator as the polymerization initiator and performing polymerization at a temperature above 70°C and below 98°C, the amount of fluorinated compound (A) relative to the aqueous medium is preferably 3 ppm to 500 ppm by mass, more preferably 3 ppm to 200 ppm by mass, further preferably 5 ppm to 120 ppm by mass, and most preferably 20 ppm to 110 ppm by mass.

[0542] When using a redox polymerization initiator as the polymerization initiator and performing polymerization at a temperature above 10°C and below 40°C, the amount of fluorinated compound (A) relative to the aqueous medium is preferably 3 ppm to 300 ppm by mass, more preferably 3 ppm to 100 ppm by mass, further preferably 5 ppm to 80 ppm by mass, and most preferably 10 ppm to 70 ppm by mass.

[0543] When using a redox polymerization initiator as the polymerization initiator and performing polymerization at 40°C to 70°C, the amount of fluorinated compound (A) relative to the aqueous medium is preferably 3 ppm to 500 ppm by mass, more preferably 5 ppm to 300 ppm by mass, further preferably 10 ppm to 200 ppm by mass, and most preferably 15 ppm to 150 ppm by mass.

[0544] When using a redox polymerization initiator as the polymerization initiator and performing polymerization at a temperature above 70°C and below 98°C, the amount of fluorinated compound (A) relative to the aqueous medium is preferably 5 ppm to 500 ppm by mass, more preferably 8 ppm to 300 ppm by mass, further preferably 15 ppm to 200 ppm by mass, and most preferably 20 ppm to 150 ppm by mass.

[0545] By keeping the amount of fluorinated compound (A) within the above range, the adhesion rate can be further reduced, and the polymerization time can be shortened.

[0546] The fluorinated compound (A) is preferably added before the polymerization initiator is added to initiate the polymerization reaction. Alternatively, it is preferable to add it only before the polymerization reaction is initiated, and not after polymerization initiation.

[0547] In the manufacturing method of the present invention, the polymerization temperature for polymerizing the fluorinated monomer is preferably 10°C to 120°C, more preferably 20°C to 100°C. Furthermore, from the perspective of reducing the stability of the aqueous dispersion and decreasing the adhesion rate, the polymerization temperature is preferably 15°C to 60°C, more preferably 18°C ​​to 55°C, and even more preferably 20°C to 50°C. Additionally, from the perspective of high polymerization rate, which results in a fluorinated elastomer with excellent physical properties, the polymerization temperature is preferably 60°C to 120°C, more preferably 60°C to 100°C, and even more preferably 70°C to 90°C.

[0548] In the manufacturing method of the present invention, the polymerization pressure used for polymerizing the fluorinated monomer is preferably 0.5 MPaG to 10 MPaG, more preferably 1 MPaG to 7 MPaG.

[0549] In the polymerization of fluorinated monomers, phosphates, sodium hydroxide, potassium hydroxide, ammonia, etc. can be used as pH adjusters.

[0550] In the manufacturing method of the present invention, the fluorinated monomer can be polymerized in the presence or absence of fluorinated monomer polymer seed particles.

[0551] The aforementioned "fluorinated monomer polymerization seed particles" are obtained by polymerizing fluorinated monomers in an aqueous medium. They exist during the second polymerization process, where the types or proportions of monomers and additives (e.g., polymerization initiators) constituting the polymerization reaction system differ, as do the reaction conditions. These fluorinated monomer polymerization seed particles function as so-called seed particles during the polymerization of the fluorinated monomers, constituting the polymerization of the fluorinated monomers in the presence of these seed particles, a process known as seed polymerization. In the manufacturing method of this invention, this seed polymerization may not be performed during the polymerization of the fluorinated monomers.

[0552] The manufacturing method of the present invention polymerizes fluorinated monomers in the presence of compound (1) and an aqueous medium, thereby suppressing the adhesion of the polymer (fluorinated elastomer) to the polymerization tank. The polymer adhesion rate on the polymerization tank is preferably 8% by mass or less, more preferably 4% by mass or less, further preferably 2% by mass or less, and most preferably 1% by mass or less.

[0553] Polymer adhesion rate is the ratio of the mass of polymer adhering to the polymerization tank after polymerization termination to the total amount of polymer (fluorinated elastomer) after polymerization termination (adhesion rate on the polymerization tank). Polymer adhering includes: polymer adhering to the inner wall of the polymerization tank or the interior of the polymerization tank, such as the agitator, after the aqueous dispersion is extracted from the polymerization tank after polymerization termination; and polymer that has been freed from the aqueous dispersion through coagulation and is suspended or precipitated without being dispersed in the aqueous dispersion. The mass of polymer adhering is the mass after removing the water content contained in the polymer adhering by drying at 120°C.

[0554] Polymer adhesion rate (mass%) = Mass of polymer adhered material / Mass of obtained polymer (including adhered material) × 100

[0555] The mass of the obtained polymer = mass of the aqueous dispersion × concentration of solids in the aqueous dispersion (mass%) / 100 + mass of polymer adhering material

[0556] In one embodiment of the manufacturing method of the present invention, the fluorinated monomer is polymerized in the presence of a non-fluorinated surfactant (hydrocarbon surfactant) (excluding compound (1)). In another embodiment of the manufacturing method of the present invention, the fluorinated monomer is polymerized in the absence of a substantially non-fluorinated surfactant (hydrocarbon surfactant) (excluding compound (1)). According to the manufacturing method of the present invention, even when the fluorinated monomer is polymerized in the absence of a non-fluorinated surfactant, the adhesion of the fluorinated elastomer to the polymerization tank can be suppressed, while a sufficient number of fluorinated elastomer particles are produced at a high polymerization rate.

[0557] In one embodiment of the manufacturing method of the present invention, the fluorinated monomer is polymerized under conditions where fluorinated surfactants are substantially absent (excluding fluorinated compound (A)). According to the manufacturing method of the present invention, even when the fluorinated monomer is polymerized under conditions where fluorinated surfactants are absent, the adhesion of the fluorinated elastomer to the polymerization tank can be suppressed, while a sufficient number of fluorinated elastomer particles are produced at a high polymerization rate.

[0558] Examples of fluorinated surfactants include anionic fluorinated surfactants. For instance, anionic fluorinated surfactants may contain fluorine atoms and have a total carbon number of 20 or less, excluding the anionic group.

[0559] Furthermore, the aforementioned fluorinated surfactants can also be fluorinated surfactants with anionic moiety having a molecular weight of 800 or less. It should be noted that the "anionic moiety" mentioned above refers to the portion of the aforementioned fluorinated surfactant other than the cationic moiety. For example, F(CF2) shown in formula (I) described later. n1 In the case of COOM, it is "F(CF2)". n1 The "COO" part.

[0560] Furthermore, examples of fluorinated surfactants mentioned above include those with a LogPOW of 3.5 or less. LogPOW is the partition coefficient between 1-octanol and water, expressed as LogP [where P represents the ratio of the concentration of the fluorinated surfactant in octanol to the concentration of the fluorinated surfactant in water during phase separation in an octanol / water (1:1) mixture containing the fluorinated surfactant].

[0561] The above LogPOW is calculated as follows: In column: TOSOH ODS-120T column ( Under the following conditions (manufactured by Tosoh Corporation), eluent: acetonitrile / 0.6% HClO4 water = 1 / 1 (vol / vol%), flow rate: 1.0 ml / min, sample volume: 300 μL, column temperature: 40℃, detection light: UV210 nm, HPLC was performed on standard substances (heptanoic acid, octanoic acid, nonanoic acid, and decanoic acid) with known octanol / water partition coefficients. Calibration curves were prepared for each elution time and the known octanol / water partition coefficient. Based on these calibration curves, the elution time in the sample solution was calculated by HPLC.

[0562] Specifically, examples of the aforementioned fluorinated surfactants include U.S. Patent Application Publication No. 2007 / 0015864, U.S. Patent Application Publication No. 2007 / 0015865, U.S. Patent Application Publication No. 2007 / 0015866, U.S. Patent Application Publication No. 2007 / 0276103, U.S. Patent Application Publication No. 2007 / 0117914, U.S. Patent Application Publication No. 2007 / 142541, U.S. Patent Application Publication No. 2008 / 0015319, and U.S. Patent No. 3250808. Fluorinated surfactants described in patents such as U.S. Patent No. 3,271,341, Japanese Patent Application Publication No. 2003-119204, International Publication No. 2005 / 042593, International Publication No. 2008 / 060461, International Publication No. 2007 / 046377, Japanese Patent Application Publication No. 2007-119526, International Publication No. 2007 / 046482, International Publication No. 2007 / 046345, U.S. Patent Application Publication No. 2014 / 0228531, International Publication No. 2013 / 189824, and International Publication No. 2013 / 189826.

[0563] As examples of the aforementioned anionic fluorinated surfactants, the following general formula (N) can be cited. 0 ):

[0564] X n0 -Rf n0 -Y 0 (N 0 )

[0565] (where X) n0 For H, Cl, or F. Rf n0 It is a chain, branched, or cyclic alkylene group with 3 to 20 carbon atoms, in which some or all of the hydrogen atoms are replaced by hydrogen atoms (F). This alkylene group may contain more than one ether bond, and some of the hydrogen atoms may be replaced by chloride (Cl). 0The compound shown is an anionic group.

[0566] Y 0 The anionic group can be -COOM, -SO2M or -SO3M, or it can be -COOM or -SO3M.

[0567] M represents H, a metal atom, and NR. 7 4. Imidazolium with or without substituents, pyridinium with or without substituents, or phosphonium with or without substituents, R 7 It can be -H or an organic group.

[0568] Examples of metal atoms mentioned above include alkali metals (Group 1) and alkaline earth metals (Group 2), such as Na, K, or Li.

[0569] As R 7 It can be H or C 1-10 The organic group can also be H or C. 1-4 The organic groups can also be H or C. 1-4 Alkyl groups.

[0570] M can be H, a metal atom, or NR. 7 4, can also be H, alkali metals (Group 1), alkaline earth metals (Group 2), or NR. 7 4. It can also be H, Na, K, Li or NH4.

[0571] The above Rf n0 In this process, more than 50% of H can be replaced by fluorine.

[0572] As the above general formula (N) 0 Examples of compounds shown in the diagram include:

[0573] The following general formula (N) 1 ):

[0574] X n0 -(CF2) m1 -Y 0 (N 1 )

[0575] (where X) n0 H, Cl, and F are given, m1 is an integer from 3 to 15, and Y is given. 0 Compounds represented by the substances defined above; compounds of the following general formula (N 2 ):

[0576] Rf n1 -O-(CF(CF3)CF2O) m2 CFX n1 -Y 0 (N 2 )

[0577] (where Rf) n1 It is a perfluoroalkyl group with 1 to 5 carbon atoms, m2 is an integer from 0 to 3, X n1 For F or CF3, Y 0 Compounds represented by the substances defined above; compounds of the following general formula (N 3 ):

[0578] Rf n2 (CH2) m3 -(Rf n3 ) q -Y 0 (N 3 )

[0579] (where Rf) n2 It is an alkyl group with 1 to 13 carbon atoms, which may contain ether bonds or be partially or fully fluorinated, m3 is an integer from 1 to 3, and Rf n3 It is a straight-chain or branched perfluoroalkylene group with 1 to 3 carbon atoms, where q is 0 or 1, and Y is... 0 Compounds represented by the substances defined above; compounds of the following general formula (N 4 ):

[0580] Rf n4 -O-(CY n1 Y n2 ) p CF2-Y 0 (N 4 )

[0581] (where Rf) n4 Y is a straight-chain or branched partially or fully fluorinated alkyl group having 1 to 12 carbon atoms and may contain ether bonds and / or chlorine atoms. n1 and Y n2 Same or different, H or F, p is 0 or 1, Y 0 Compounds represented by the substances defined above; and compounds of the following general formula (N 5 ):

[0582] [Chemistry 21]

[0583]

[0584] (where X) n2 X n3 and X n4 They can be the same or different, and can be H, F, or a straight-chain or branched partially or fully fluorinated alkyl group having 1 to 6 carbon atoms and containing ether bonds. Rf n5 It is a linear or branched partially or fully fluorinated alkylene group with 1 to 3 carbon atoms, which may contain ether bonds, where L is a linking group and Y is a linking group.0 The substance is defined above. Where X is... n2 X n3 X n4 and Rf n5 The compound shown has a total number of carbon atoms of 18 or less.

[0585] As a general formula (N) 0 The compounds shown in the formula (I) are, more specifically, perfluorocarboxylic acids (I) represented by the general formula (II), ω-H perfluorocarboxylic acids (II) represented by the general formula (III), perfluoropolyether carboxylic acids (III) represented by the general formula (III), perfluoroalkylalkylene carboxylic acids (IV) represented by the general formula (IV), perfluoroalkoxyfluorocarboxylic acids (V) represented by the general formula (V), perfluoroalkylsulfonic acids (VI) represented by the general formula (VI), ω-H perfluorosulfonic acids (VII) represented by the general formula (VII), perfluoroalkylalkylene sulfonic acids (VIII) represented by the general formula (VIII), alkylalkylene carboxylic acids (IX) represented by the general formula (IX), fluorocarboxylic acids (X) represented by the general formula (X), alkoxyfluorosulfonic acids (XI) represented by the general formula (XI), compounds (XII) represented by the general formula (XII), and compounds (XIII) represented by the general formula (XIII).

[0586] The above-mentioned perfluorocarboxylic acid (I) is derived from the following general formula (I).

[0587] F(CF2) n1 COOM(I)

[0588] (In the formula, n1 is an integer from 3 to 14, M is H, metal atom, NR) 7 4. Imidazolium with or without substituents, pyridinium with or without substituents, or phosphonium with or without substituents, R 7 It is represented by H or an organic group.

[0589] The above-mentioned ω-H perfluorocarboxylic acids (II) are derived from the following general formula (II).

[0590] H(CF2) n2 COOM(II)

[0591] (where n2 is an integer from 4 to 15, and M is the substance defined above.)

[0592] The above-mentioned perfluoroether carboxylic acid (III) is derived from the following general formula (III).

[0593] Rf 1 -O-(CF(CF3)CF2O) n3 CF(CF3)COOM(III)

[0594] (where Rf) 1 It is represented by a perfluoroalkyl group having 1 to 5 carbon atoms, n3 being an integer from 0 to 3, and M being a substance as defined above.

[0595] The above-mentioned perfluoroalkylalkylene carboxylic acids (IV) are derived from the following general formula (IV).

[0596] Rf 2 (CH2) n4 Rf 3 COOM(IV)

[0597] (where Rf) 2 It is a perfluoroalkyl group with 1 to 5 carbon atoms, Rf 3 It is represented by a straight-chain or branched perfluoroalkylene group with 1 to 3 carbon atoms (n4 is an integer from 1 to 3, and M is a substance as defined above).

[0598] The above-mentioned alkoxyfluorocarboxylic acid (V) is derived from the following general formula (V).

[0599] Rf 4 -O-CY 1 Y 2 CF2-COOM(V)

[0600] (where Rf) 4 Y is a straight-chain or branched partially or fully fluorinated alkyl group having 1 to 12 carbon atoms and may contain ether bonds and / or chlorine atoms. 1 and Y 2 The same or different (H or F, M is the substance defined above) are represented by this.

[0601] The above-mentioned perfluoroalkyl sulfonic acid (VI) is produced by the following general formula (VI).

[0602] F(CF2) n5 SO3M(VI)

[0603] (In the formula, n5 is an integer from 3 to 14, and M is the substance defined above.)

[0604] The above-mentioned ω-H perfluorosulfonic acid (VII) is derived from the following general formula (VII).

[0605] H(CF2) n6 SO3M(VII)

[0606] (In the formula, n6 is an integer from 4 to 14, and M is the substance defined above.)

[0607] The above-mentioned perfluoroalkyl alkylene sulfonic acid (VIII) is produced by the following general formula (VIII).

[0608] Rf5 (CH2) n7 SO3M(VIII)

[0609] (where Rf) 5 It is represented by a perfluoroalkyl group having 1 to 13 carbon atoms, n7 being an integer from 1 to 3, and M being a substance as defined above.

[0610] The above-mentioned alkylalkylene carboxylic acids (IX) are derived from the following general formula (IX).

[0611] Rf 6 (CH2) n8 COOM(IX)

[0612] (where Rf) 6 It is represented by a straight-chain or branched partially or fully fluorinated alkyl group with 1 to 13 carbon atoms that may contain ether bonds, where n8 is an integer from 1 to 3 and M is a substance as defined above.

[0613] The above-mentioned fluorocarboxylic acid (X) is derived from the following general formula (X).

[0614] Rf 7 -O-Rf 8 -O-CF2-COOM(X)

[0615] (where Rf) 7 It is a straight-chain or branched partially or fully fluorinated alkyl group having 1 to 6 carbon atoms and may contain ether bonds and / or chlorine atoms, Rf 8 It is represented by a straight-chain or branched partially or fully fluorinated alkyl group having 1 to 6 carbon atoms (M being a substance as defined above).

[0616] The above-mentioned alkoxyfluorosulfonic acid (XI) is derived from the following general formula (XI).

[0617] Rf 9 -O-CY 1 Y 2 CF2-SO3M(XI)

[0618] (where Rf) 9 It is a straight-chain or branched alkyl group with 1 to 12 carbon atoms, which may contain ether bonds and may be partially or fully fluorinated with chlorine. 1 and Y 2 The same or different (H or F, M is the substance defined above) are represented by this.

[0619] The above compound (XII) is derived from the following general formula (XII):

[0620] [Chemistry 22]

[0621]

[0622] (where X) 1 X 2 and X 3 They can be the same or different, and are H, F, and linear or branched partially or fully fluorinated alkyl groups with 1 to 6 carbon atoms, which may contain ether bonds; Rf 10 It is a perfluoroalkylene group with 1 to 3 carbon atoms, where L is a linking group and Y is a linking group. 0 It is represented by an anionic group.

[0623] Y 0 It can be -COOM, -SO2M or -SO3M, or -SO3M or COOM (where M is the substance defined above).

[0624] Examples of L include single bonds, partially or fully fluorinated alkylene groups with 1 to 10 carbon atoms that may contain ether bonds.

[0625] The above compound (XIII) is derived from the following general formula (XIII).

[0626] Rf 11 -O-(CF2CF(CF3)O) n9 (CF2O) n10 CF2COOM (XIII)

[0627] (where Rf) 11 It is represented by a fluoroalkyl group containing chlorine with 1 to 5 carbon atoms, where n9 is an integer from 0 to 3, n10 is an integer from 0 to 3, and M is a substance as defined above. Examples of compounds (XIII) include CF2ClO (CF2CF(CF3)O). n9 (CF2O) n10 CF2COONH4 (a mixture with an average molecular weight of 750, where n9 and n10 are the numbers defined above).

[0628] In one embodiment of the manufacturing method of the present invention, a fluorinated monomer is polymerized in the presence of a fluorinated surfactant (excluding compound (1) and fluorinated compound (A)). In another embodiment of the manufacturing method of the present invention, it is possible to polymerize the monomer in the absence of the general formula: X-(CF2). m2 Fluorinated monomers are polymerized under conditions containing a fluorinated compound as indicated by -Y. In one embodiment of the manufacturing method of the present invention, it is possible to polymerize fluorinated monomers in the presence of a fluorinated surfactant (wherein neither compound (1) nor fluorinated compound (A) is present) and in the absence of the general formula: X-(CF2). m2 Fluorine monomers are polymerized under the conditions indicated by -Y for fluorine-containing compounds.

[0629] As a fluorinated surfactant that can exist during polymerization (excluding fluorinated compounds (A)), the general formula X-(CF2) can be cited among fluorinated surfactants. m2 -Y (where X represents H or F, m2 represents an integer of 6 or more, and Y represents a fluorinated surfactant other than the fluorinated compounds shown in -SO3M, -SO4M, -SO3R, -SO4R, -COOM, -PO3M2, -PO4M2 (M represents H, NH4, or an alkali metal, and R represents an alkyl group with 1 to 12 carbon atoms)). That is, in one embodiment of the manufacturing method of the present invention, it is preferable to use a fluorinated surfactant (wherein fluorinated compounds (A) and general formula: X-(CF2) are excluded). m2 Fluorinated monomers are polymerized in the presence of a fluorinated compound (represented by -Y).

[0630] As a fluorinated surfactant that can exist during polymerization, and as a fluorinated surfactant that does not exist during polymerization, among the fluorinated surfactants exemplified above, the general formula X-(CF2) can be cited. m2 -Y (where X represents H or F, m2 represents an integer of 6 or more, and Y represents fluorinated surfactants other than those shown as -SO3M, -SO4M, -SO3R, -SO4R, -COOM, -PO3M2, -PO4M2 (M represents H, NH4 or an alkali metal, and R represents an alkyl group with 1 to 12 carbon atoms)). Furthermore, examples of fluorinated surfactants that can be present during polymerization include those described in International Publication Nos. 2019 / 009248, 2007 / 120346, 2007 / 011633, 2007 / 011631, and 2007 / 062059.

[0631] According to the manufacturing method of the present invention, an aqueous dispersion of a fluorinated elastomer is obtained. The solid content concentration (fluorinated elastomer content) of the obtained aqueous dispersion of the fluorinated elastomer at the moment of polymerization termination is preferably 10% to 50% by mass, more preferably 15% to 40% by mass, and even more preferably 20% to 30% by mass.

[0632] The aqueous dispersion obtained by the manufacturing method of the present invention and the fluorinated elastomer contained in the aqueous dispersion of the present invention may contain monomer units based on compound (1).

[0633] The present invention also relates to a fluorinated elastomer containing monomer units based on compound (1) and having -CH2- in the main chain. The fluorinated elastomer of the present invention is preferably manufactured by the manufacturing method of the present invention.

[0634] The content of monomer units based on compound (1) in the fluorinated elastomer is preferably 0.0009% to 1.5% by mass relative to all monomer units, more preferably 0.0015% by mass or more, further 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, further preferably 0.15% by mass or less, particularly preferably 0.09% by mass or less, and most preferably 0.06% by mass or less. If the content of monomer units based on compound (1) is too high, the required properties of the fluorinated elastomer may be impaired.

[0635] The content of monomer units based on compound (1) in fluorinated elastomers can be calculated by appropriately combining NMR, FT-IR, elemental analysis, and fluorescence X-ray analysis according to the type of monomer.

[0636] Furthermore, the present invention relates to an aqueous dispersion comprising a fluorinated elastomer containing -CH2- in its main chain and an aqueous medium. The aqueous dispersion of the present invention can be suitably manufactured using the manufacturing method of the present invention.

[0637] The fluorinated elastomer in the aqueous dispersion of the present invention can have the same composition as the fluorinated elastomer contained in the aqueous dispersion obtained by the manufacturing method of the present invention. For example, the fluorinated elastomer can contain monomer units based on compound (1). The fluorinated elastomer can contain monomer units based on fluorinated monomers.

[0638] The content (solid component concentration) of fluorinated elastomer in the aqueous dispersion is preferably 10% to 50% by mass, more preferably 15% to 40% by mass, and even more preferably 20% to 30% by mass.

[0639] Regarding the solid component concentration of an aqueous dispersion of fluorinated elastomers, 1g of the aqueous dispersion is dried at 150℃ for 180 minutes, the mass of the heating residue is measured, and the ratio of the mass of the heating residue to the mass of the aqueous dispersion is calculated, thereby specifying the solid component concentration.

[0640] The aqueous dispersion of fluorinated elastomers may contain fluorinated elastomer particles. The average particle size of the fluorinated elastomer particles is preferably 10 nm to 800 nm, more preferably 50 nm to 500 nm, and even more preferably 70 nm to 300 nm. The average particle size of the fluorinated elastomer particles is the cumulative average particle size, which can be determined by dynamic light scattering.

[0641] The number of fluorinated elastomer particles contained in the aqueous dispersion of the fluorinated elastomer is preferably 1.0 × 10⁻⁶. 12 5.0 × 10⁻⁶ pcs / cc or more, preferably 5.0 × 10⁻⁶ pcs / cc or more. 121.0 × 10⁻⁶ pcs / cc or more, preferably 1.0 × 10⁻⁶ pcs / cc or more. 13 The particle count (number of polymer particles) can be calculated using the following formula.

[0642] [Number 1]

[0643]

[0644] The number of fluorinated elastomer particles obtained from the above formula is the number of particles per 1 cc of water. The specific gravity is the specific gravity of the fluorinated elastomer. The specific gravity of the fluorinated elastomer can be calculated according to JIS Z 8807:2012.

[0645] In one embodiment of the aqueous dispersion, a fluorinated surfactant is contained (excluding fluorinated compound (A)). The aqueous dispersion containing the fluorinated surfactant has the advantage of being able to be stably manufactured at high productivity using the fluorinated surfactant (excluding fluorinated compound (A)). As the fluorinated surfactant, preferred surfactants include those excluding compound (1), fluorinated compound (A), and those of the general formula: X-(CF2). m2 Fluorinated compounds (represented by -Y) can be exemplified as fluorinated surfactants that may be present during polymerization. Fluorinated surfactants (excluding compounds (1) and fluorinated compound (A)) are more preferred as fluorinated surfactants. The aqueous dispersion may not contain the general formula: X-(CF2). m2 -Y represents the fluorine-containing compound.

[0646] In one embodiment of the aqueous dispersion, it substantially does not contain fluorinated surfactants (excluding fluorinated compound (A)). An aqueous dispersion substantially free of fluorinated surfactants requires polymerization of fluorinated monomers without the use of fluorinated surfactants (excluding compound (1) and fluorinated compound (A)), but can be manufactured using the method for manufacturing the fluorinated elastomer of the present invention by using compound (1).

[0647] In this invention, "substantially free of fluorinated surfactants" means that the content of fluorinated surfactants (excluding compound (1) and fluorinated compound (A)) in the aqueous dispersion is less than 10 ppm by mass, preferably less than 1 ppm by mass, more preferably less than 100 ppb by mass, further preferably less than 10 ppb by mass, even more preferably less than 1 ppb by mass, and particularly preferably less than the detection limit of the fluorinated surfactants determined by liquid chromatography-mass spectrometry (LC / MS / MS).

[0648] The content of fluorinated surfactants (excluding fluorinated compounds (A)) can be quantified using known methods. For example, quantification can be performed by LC / MS analysis. First, methanol is added to an aqueous dispersion for extraction, and the resulting extract is analyzed by LC / MS.

[0649] To further improve extraction efficiency, processing methods such as Soxhlet extraction and ultrasonic treatment can be used.

[0650] The molecular weight information was selected from the obtained LC / MS spectrum, and it was confirmed that it was consistent with the structural formula of the candidate fluorinated surfactant.

[0651] Subsequently, aqueous solutions containing at least five levels of the confirmed fluorinated surfactant were prepared, and LC / MS analysis was performed on the aqueous solutions at each concentration. The relationship between the concentration and the area of ​​the region relative to that concentration was plotted, and a calibration curve was drawn.

[0652] Furthermore, by using calibration curves, the area of ​​the LC / MS chromatogram of fluorinated surfactants in the extract can be converted into the content of fluorinated surfactants.

[0653] Aqueous dispersions of fluorinated elastomers may further include crosslinking agents, fillers, etc. Crosslinking agents, etc., are described below.

[0654] Aqueous dispersions of fluorinated elastomers can be prepared by adding or concentrating dispersants such as hydrocarbon surfactants as needed, thereby creating dispersions suitable for rubber molding. These dispersions are then subjected to pH adjustment, coagulation, and heating processes.

[0655] It can also be used to treat aqueous dispersions of fluorinated elastomers by precipitation, heating, etc.

[0656] The above precipitation can be achieved by adding alkaline earth and earth metal salts to an aqueous dispersion. Examples of alkaline earth and earth metal salts include sulfates, nitrates, hydrochlorides, and acetates of calcium, magnesium, aluminum, etc.

[0657] The precipitated fluorinated elastomer can be washed with water to remove small amounts of buffer solution and salt impurities present in the fluorinated elastomer, and then the washed fluorinated elastomer can be dried. The drying temperature is preferably 40℃~200℃, more preferably 60℃~180℃, and even more preferably 80℃~150℃.

[0658] The present invention also relates to a composition comprising a fluorinated elastomer containing -CH2- in the main chain. The compositions of the present invention can be suitably manufactured by the manufacturing method of the present invention.

[0659] The fluorinated elastomer in the composition of the present invention may have the same composition as the fluorinated elastomer contained in the aqueous dispersion obtained by the manufacturing method of the present invention. For example, the fluorinated elastomer may contain monomer units based on compound (1). The fluorinated elastomer may contain monomer units based on fluorinated monomers.

[0660] The form of the fluorinated elastomer and composition is not particularly limited, and can be gum, crumb, powder, granules, etc., preferably gum or crumb. A gum is a granular block composed of fluorinated elastomers, while a crumb is an amorphous block formed when the fluorinated elastomers, unable to maintain their granular form as gum at room temperature, fuse together. Gum or crumb is obtained by appropriately using existing known methods to precipitate, dry, etc., the aqueous dispersion obtained by the manufacturing method of the present invention.

[0661] The moisture 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 moisture content of the composition can be calculated, for example, by heating the composition to above 120°C to dry it sufficiently, measuring the weight of the composition before and after heating, and dividing the weight reduction by the weight before heating.

[0662] In one embodiment of the composition of the present invention, a fluorinated surfactant is contained (excluding compound (1) and fluorinated compound (A)). The composition containing the fluorinated surfactant has the advantage of being able to be stably manufactured at high productivity using the fluorinated surfactant (excluding compound (1) and fluorinated compound (A)). As the fluorinated surfactant, a fluorinated surfactant (excluding fluorinated compound (A) and the general formula: X-(CF2)) is preferred. m2 Fluorinated compounds (represented by -Y) can be exemplified as fluorinated surfactants that can be present during polymerization. Fluorinated surfactants (excluding compound (1) fluorinated compound (A)) are more preferred as fluorinated surfactants. The composition may not contain the general formula: X-(CF2). m2 -Y represents the fluorine-containing compound.

[0663] In one embodiment of the composition of the present invention, there is substantially no fluorinated surfactant (excluding compound (1) and fluorinated compound (A)). A composition substantially free of fluorinated surfactant requires polymerization of fluorinated monomers without the use of fluorinated surfactants (excluding compound (1) and fluorinated compound (A)), but can be manufactured using the method of manufacturing the fluorinated elastomer of the present invention by using compound (1).

[0664] In this invention, "substantially free of fluorinated surfactants" means that the content of fluorinated surfactants in the composition (excluding compound (1) and fluorinated compound (A)) is less than 10 ppm by mass, preferably less than 1 ppm by mass, more preferably less than 100 ppb by mass, further preferably less than 10 ppb by mass, even more preferably less than 1 ppb by mass, and particularly preferably less than the detection limit of the fluorinated surfactants determined by liquid chromatography-mass spectrometry (LC / MS).

[0665] The content of fluorinated surfactants (excluding compound (1) and fluorinated compound (A)) can be quantified using known methods. For example, it can be quantified by LC / MS analysis. First, methanol is added to the composition for extraction, and the resulting extract is analyzed by LC / MS.

[0666] To further improve extraction efficiency, processing methods such as Soxhlet extraction and ultrasonic treatment can be used.

[0667] The molecular weight information was selected from the obtained LC / MS spectrum, and it was confirmed that it was consistent with the structural formula of the candidate fluorinated surfactant.

[0668] Subsequently, aqueous solutions containing at least five levels of the confirmed fluorinated surfactant were prepared, and LC / MS analysis was performed on the aqueous solutions at each concentration. The relationship between the concentration and the area of ​​the region relative to that concentration was plotted, and a calibration curve was drawn.

[0669] Furthermore, by using calibration curves, the area of ​​the LC / MS chromatogram of fluorinated surfactants in the extract can be converted into the content of fluorinated surfactants.

[0670] The compositions of the present invention may further comprise crosslinking agents, fillers, etc. Crosslinking agents, etc., are described below.

[0671] By adding crosslinking agents, fillers, etc., to the fluorinated elastomer obtained by the manufacturing method of the present invention, the fluorinated elastomer of the present invention, or the composition of the present invention, a fluorinated elastomer composition can be manufactured. The type and amount of crosslinking agents and fillers are not particularly limited and can be used within the known range.

[0672] The method for obtaining the above-mentioned fluorinated elastomer composition is not particularly limited as long as a method capable of uniformly mixing the fluorinated elastomer obtained by the manufacturing method of the present invention, the fluorinated elastomer of the present invention, or the composition of the present invention with a crosslinking agent, filler, etc. can be used. For example, the following method can be used: mixing the powder obtained by separately precipitating the fluorinated elastomer with other additives and compounding agents as needed using a mixing mill such as an open mill.

[0673] When the aforementioned fluorinated elastomer is an uncrosslinked elastomer, its crosslinking system can include, for example, a peroxide crosslinking system, a polyol crosslinking system, or a polyamine crosslinking system, preferably at least one selected from the group consisting of a peroxide crosslinking system and a polyol crosslinking system. From the perspective of chemical resistance, a peroxide crosslinking system is preferred, and from the perspective of heat resistance, a polyol crosslinking system is preferred.

[0674] Therefore, as the aforementioned crosslinking agent, at least one crosslinking agent selected from the group consisting of polyol crosslinking agents and peroxide crosslinking agents is preferred, and peroxide crosslinking agents are more preferred.

[0675] The amount of crosslinking agent can be appropriately selected according to the type of crosslinking agent, and is preferably 0.2 to 6.0 parts by mass, more preferably 0.3 to 5.0 parts by mass, relative to 100 parts by mass of fluorinated elastomer.

[0676] Peroxide crosslinking can be achieved by using an uncrosslinked elastomer capable of peroxide crosslinking as a fluorinated elastomer and an organic peroxide as a crosslinking agent.

[0677] There are no particular limitations on the type of uncrosslinked elastomer capable of peroxide crosslinking; any uncrosslinked elastomer having a portion capable of peroxide crosslinking is acceptable. The portion capable of peroxide crosslinking is not particularly limited; examples include portions containing iodine atoms or portions containing bromine atoms.

[0678] As an organic peroxide, any organic peroxide that can readily generate peroxide free radicals in the presence of heat or a redox system is acceptable. Examples include 1,1-bis(tert-butylperoxy)-3,5,5-trimethylcyclohexane, 2,5-dimethylhexane-2,5-dihydroperoxide, di-tert-butylperoxide, tert-butylcumylperoxide, dicumylperoxide, α,α-bis(tert-butylperoxy)-p-diisopropylbenzene, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)-3-hexyne, benzoyl peroxide, tert-butyl peroxide, tert-butyl maleate peroxide, tert-butyl isopropyl carbonate peroxide, and tert-butyl benzoate peroxide. Among these, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and 2,5-dimethyl-2,5-di(tert-butylperoxy)-3-hexyne are preferred.

[0679] The amount of organic peroxide mixed with fluorinated elastomer is preferably 0.1 to 15 parts by mass, more preferably 0.3 to 5 parts by mass, relative to 100 parts by mass of fluorinated elastomer.

[0680] When the crosslinking agent is an organic peroxide, the above-mentioned fluorinated elastomer composition preferably further comprises a crosslinking aid. Examples of crosslinking aids include, for instance, triallyl cyanurate, triallyl isocyanurate (TAIC), 1,3,5-triacryloylhexahydro-1,3,5-triazine, triallyl trimellitate, N,N′-m-phenylene bismaleimide, diacetylacetate, diallyl phthalate, tetraallyl terephthalamide, triallyl phosphate, bismaleimide, and fluorinated triallyl isocyanurate (1,3,5-tris(2,3,3-trifluoro-2-propenyl)-1,3,5-trimethoxy-2-propenyl)-1,3,5-trimethoxy-2-propenyl)-1,3,5-trimethoxy-2-propenyl)-2-propenyl cyanurate. Triazine-2,4,6-trione, tris(diallylamine)-triazine, N,N-diallylacrylamide, 1,6-divinyldodecylfluorohexane, hexamethylenephosphoramide, N,N,N′,N′-tetraallylphthalamide, N,N,N′,N′-tetraallylmalondiamide, trivinyl isocyanurate, 2,4,6-trivinylmethyltrisiloxane, tris(5-norbornene-2-methylene)cyanurate, triallyl phosphite, trimethylallyl isocyanurate, etc. Among these, triallyl isocyanurate (TAIC) is preferred due to its excellent crosslinking properties, mechanical properties, and flexibility.

[0681] The amount of crosslinking aid mixed with 100 parts by weight of fluorinated elastomer is preferably 0.01 to 10 parts by weight, more preferably 0.01 to 7.0 parts by weight, and even more preferably 0.1 to 5.0 parts by weight. If the amount of crosslinking aid is less than 0.01 parts by weight, the mechanical properties or the softness will decrease. If it exceeds 10 parts by weight, it tends to have poor heat resistance and reduced durability of the molded article.

[0682] Polyol crosslinking can be achieved by using an uncrosslinked elastomer capable of polyol crosslinking as a fluorinated elastomer and a polyhydroxy compound as a crosslinking agent. The amount of the polyhydroxy compound in the polyol crosslinking system is preferably 0.01 to 10 parts by mass relative to 100 parts by mass of the uncrosslinked elastomer capable of polyol crosslinking. By keeping the amount of the polyhydroxy compound within this range, sufficient polyol crosslinking can be achieved. More preferably, it is 0.02 to 8 parts by mass. Even more preferably, it is 0.03 to 4 parts by mass.

[0683] The uncrosslinked elastomer capable of polyol crosslinking is not particularly limited, as long as it is an uncrosslinked elastomer having a portion capable of polyol crosslinking. The portion capable of polyol crosslinking is not particularly limited, and examples include portions having vinylidene fluoride (VdF) units. As a method for introducing the crosslinking portion, methods such as copolymerizing monomers providing the crosslinking portion during the polymerization of the uncrosslinked elastomer can be used.

[0684] From the perspective of excellent heat resistance, polyhydroxy aromatic compounds are preferred as polyhydroxy compounds.

[0685] As for the aforementioned polyhydroxy aromatic compounds, there are no particular limitations, but examples 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 can be obtained, for example, from Fujifilm, Kojun Pharmaceutical, Chuo Glass Co., Ltd., etc.), 1,3-dihydroxybenzene, 1,7-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 4,4'-dihydroxybiphenyl, and diphenyl Ethylene-4,4'-diol, 2,6-dihydroxyanthracene, hydroquinone, catechol, 2,2-bis(4-hydroxyphenyl)butane (hereinafter referred to as bisphenol B), 4,4-bis(4-hydroxyphenyl)valerate, 2,2-bis(4-hydroxyphenyl)tetrafluorodichloropropane, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl ketone, tris(4-hydroxyphenyl)methane, 3,3',5,5'-tetrachlorobisphenol A, 3,3',5,5'-tetrabromobisphenol A, etc. These polyhydroxy aromatic compounds can be alkali metal salts, alkaline earth metal salts, etc., and it is preferable not to use the above-mentioned metal salts when precipitating the copolymer with acid. The amount of the polyhydroxy aromatic compound in the mixture is 0.1 to 15 parts by weight, preferably 0.5 to 5 parts by weight, relative to 100 parts by weight of the uncrosslinked elastomer.

[0686] When the crosslinking agent is a polyhydroxy compound, the above-mentioned fluorinated elastomer composition preferably further comprises a crosslinking promoter. The crosslinking promoter can promote the formation of intramolecular double bonds in the dehydrofluoric acid reaction of the polymer backbone and the addition of polyhydroxy compounds to the formed double bonds.

[0687] It should be noted that crosslinking accelerators can be further combined with acidic acceptors such as magnesium oxide and crosslinking aids for use.

[0688] Examples of crosslinking promoters include onium compounds. Among onium compounds, at least one is preferably selected from the group consisting of ammonium compounds such as quaternary ammonium salts, phosphorus onium compounds such as quaternary phosphonium salts, oxonium compounds, sulfonium compounds, cyclic amines, and monofunctional amine compounds. More preferably, at least one is selected from the group consisting of quaternary ammonium salts and quaternary phosphonium salts.

[0689] As a quaternary ammonium salt, there are no particular limitations; examples 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, and 8-methyl-1,8-diazabicyclo[5,4,0]-7 -Undecenemonium methyl sulfate, 8-ethyl-1,8-diazabicyclo[5,4,0]-7-undecenemonium bromide, 8-propyl-1,8-diazabicyclo[5,4,0]-7-undecenemonium bromide, 8-dodecyl-1,8-diazabicyclo[5,4,0]-7-undecenemonium chloride, 8-dodecyl-1,8-diazabicyclo[5,4,0]-7-undecenemonium chloride Enenium hydroxide, 8-eicosyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, 8-tetradecyl-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 can be manufactured by companies such as Fujifilm and Koden Pharmaceuticals. The following compounds are available: 8-benzyl-1,8-diazabicyclo[5,4,0]-7-undecenium hydroxide, 8-phenylethyl-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 in terms of crosslinking properties, mechanical properties, and flexibility.

[0690] In addition, there are no particular limitations on the quaternary phosphorus salt, and examples such as tetrabutylphosphine chloride, benzyltriphenylphosphine chloride (hereinafter referred to as BTPPC), benzyltrimethylphosphine chloride, benzyltributylphosphine chloride, tributylallylphosphine chloride, tributyl-2-methoxypropylphosphine chloride, and benzylphenyl(dimethylamino)phosphine chloride are preferred from the aspects of crosslinking, mechanical properties and flexibility.

[0691] Alternatively, as a crosslinking accelerator, a solid solution of quaternary ammonium salt and bisphenol AF, a solid solution of quaternary phosphonium salt and bisphenol AF, or a chlorine-free crosslinking accelerator disclosed in Japanese Patent Application Publication No. 11-147891 may also be used.

[0692] The amount of crosslinking accelerator mixed with 100 parts by weight of uncrosslinked elastomer is preferably 0.01 to 8.00 parts by weight, more preferably 0.02 to 5.00 parts by weight, and even more preferably 0.03 to 3.00 parts by weight. If the amount of crosslinking accelerator is less than 0.01 parts by weight, the crosslinking of the uncrosslinked elastomer will not be sufficient, and the heat resistance and other properties of the resulting molded article may be reduced. If the amount exceeds 8.00 parts by weight, the processability of the above-mentioned fluorinated elastomer composition may be reduced, and the elongation and softness in the mechanical properties may also be reduced.

[0693] Acid acceptors are used to neutralize acidic substances generated during the crosslinking of polyols. Specific examples include magnesium oxide, calcium hydroxide (e.g., NICC5000 (manufactured by Inoue Lime Industry Co., Ltd.), CALDIC#2000, CALDIC#1000 (manufactured by Omi Chemical Industry Co., Ltd.)), calcium oxide, lead monoxide (lead oxide), zinc white, dibasic lead phosphite, hydrotalcite, etc., preferably at least one selected from the group consisting of highly active magnesium oxide and low-activity magnesium.

[0694] Polyamine crosslinking can be achieved by using a fluorinated elastomer capable of polyamine crosslinking as the fluorinated elastomer and a polyamine compound as the crosslinking agent.

[0695] The fluorinated elastomer capable of polyamine crosslinking is not particularly limited, as long as it is a fluorinated elastomer having a portion capable of polyamine crosslinking. The portion capable of polyamine crosslinking is not particularly limited, and examples include portions having vinylidene fluoride (VdF) units. As a method for introducing the crosslinking portion, examples include copolymerizing monomers providing the crosslinking portion during the polymerization of the fluorinated elastomer.

[0696] Examples of polyamine compounds include hexamethylenediamine carbamate, N,N'-dimethylcinnamoyl-1,6-hexanediamine, and 4,4'-bis(aminocyclohexyl)methane carbamate. Among these, N,N'-dimethylcinnamoyl-1,6-hexanediamine is preferred.

[0697] The above-mentioned fluorinated elastomer composition may contain at least one multifunctional compound. A multifunctional compound is a compound having two or more functional groups with the same or different structures in one molecule. As for the functional groups of a multifunctional compound, any functional group that is generally known to be reactive, such as carbonyl, carboxyl, haloformyl, amide, olefin, amino, isocyanate, hydroxyl, or epoxy, may be used.

[0698] The above-mentioned fluorinated elastomer composition can be mixed with various common additives that need to be mixed into the elastomer, such as fillers, processing aids, plasticizers, colorants, stabilizers, adhesive aids, release agents, conductive agents, thermally conductive agents, surface non-adhesive agents, softening agents, heat resistance improvers, flame retardants, etc. These additives can be used as long as they do not impair the effects of the present invention.

[0699] Alternatively, molded articles can be obtained from the above-described fluorinated elastomer composition. Molded articles can be obtained by molding and crosslinking the above-described fluorinated elastomer composition. The above-described fluorinated elastomer composition can be molded using existing known methods. The methods and conditions for molding and crosslinking can be within the range of known methods and conditions used in molding and crosslinking. The order of molding and crosslinking is not limited; crosslinking can be performed after molding, molding can be performed after crosslinking, or molding and crosslinking can be performed simultaneously.

[0700] Examples of molding methods include, but are not limited to, pressure molding using molds and injection molding. Examples of crosslinking methods include steam crosslinking, conventional methods that initiate the crosslinking reaction by heating, and radiation crosslinking, with heating-based crosslinking being preferred. Specific crosslinking conditions are not limited, but are generally determined appropriately based on the type of crosslinking agent used, within a temperature range of 140°C to 250°C and a crosslinking time of 1 minute to 24 hours.

[0701] The resulting molded articles can be used as various components in various fields such as the automotive industry, aerospace industry, and semiconductor industry. The molded articles can be used for the same purposes as the cross-linked rubber molded articles described in Japanese Patent Application Publication No. 2013-216915 and the fluororubber molded articles described in Japanese Patent Application Publication No. 2019-94430, such as sealing materials, sliding parts, and non-adhesive parts.

[0702] As molded products, examples include various sealing materials and gaskets such as rings, gaskets, diaphragms, oil seals, and bearing seals. As sealing materials, they can be used in applications requiring excellent non-adhesion and low friction. In particular, they are suitable for various sealing applications in industries such as automotive.

[0703] In addition, it can also be used as pipes, hoses, rollers, various rubber rollers, flexible joints, rubber sheets, coatings, belts, shock absorbers, valves, valve seats, valve bodies, chemical-resistant coating materials, lamination materials, lining materials, etc.

[0704] The embodiments have been described above, but it is understood that various changes in manner and details may be made without departing from the spirit and scope of the claims.

[0705] Example

[0706] The embodiments of the present invention will be described below, but the present invention is not limited to these embodiments.

[0707] The values ​​in the examples were determined by the following method.

[0708] Solid content of aqueous dispersion

[0709] 1 g of the aqueous dispersion was dried in a blower dryer at 150 °C for 180 minutes. The mass of the heating residue was measured, and the ratio (mass%) of the mass of the heating residue to the mass of the aqueous dispersion (1 g) was calculated.

[0710] Polymer adhesion rate

[0711] The following formula is used to calculate the ratio of the mass of polymer residue adhering to the polymerization tank after polymerization termination to the total amount of polymer (fluorinated elastomer) after polymerization termination (adhesion rate on the polymerization tank).

[0712] Polymer adhesion rate (mass%) = Mass of polymer adherend / Mass of obtained polymer (including polymer adherend) × 100

[0713] The mass of the obtained polymer = mass of the aqueous dispersion × concentration of solids in the aqueous dispersion (mass%) / 100 + mass of polymer adhering material

[0714] Polymer deposits include: polymers adhering to the inner wall of the polymerization tank or the interior of the polymerization tank, such as the agitator, after the aqueous dispersion has been extracted from the polymerization tank following polymerization termination; and polymers that have been freed from the aqueous dispersion through coagulation and are suspended or precipitated without being dispersed in the aqueous dispersion. The mass of the polymer deposits is the mass after the water content in the polymer deposits has been removed by drying at 120°C.

[0715] Average particle size

[0716] The average particle size (cumulative average particle size) of the fluorinated elastomer particles in the aqueous dispersion was determined by dynamic light scattering using an ELSZ-1000S (manufactured by Otsuka Electronics Co., Ltd.), and calculated by the cumulative method.

[0717] Particle count (number of fluorinated elastomer particles in an aqueous dispersion)

[0718] The calculation is performed using the following formula.

[0719] [Number 2]

[0720]

[0721] In the formula, the average particle size is the cumulative average particle size calculated by the above method, the number of polymer particles (number of fluorinated elastomer particles) is the number of particles per 1 cc of water, and the specific gravity of all fluorinated elastomers in the examples and comparative examples is set to 1.8.

[0722] Mooney viscosity

[0723] Mooney viscosity was measured at 100°C using a Mooney viscometer MV2000E manufactured by ALPHATECHNOLOGIES, in accordance with JIS K 6300-1.2013.

[0724] Copolymer composition

[0725] It was determined by NMR analysis.

[0726] Iodine content

[0727] An absorbent solution is prepared by dissolving 30 mg of a substance (a 1:1 mass ratio of Na₂CO₃ and K₂CO₃) in 20 ml of pure water, with 5 mg of Na₂SO₃ mixed in 12 mg of fluorinated elastomer. This absorbent solution is then burned in oxygen in a quartz flask. After standing for 30 minutes, the solution can be determined using a Shimadzu 20A ion chromatograph. As calibration curves, KI standard solution, a solution containing 0.5 ppm iodide ions, and a solution containing 1.0 ppm iodide ions can be used.

[0728] The amount of -CH2I structure in fluorinated elastomers relative to the -CH2- structure per 100 mol%

[0729] Through fluorinated elastomers 1 The H-NMR spectrum was obtained.

[0730] Example 1

[0731] Add 1500g of deionized water and 0.075g of sodium p-styrene sulfonate to a 3L SUS polymerization tank. Seal the polymerization tank and purge the system with nitrogen to remove oxygen. Heat the polymerization tank to 80°C and, under stirring, force in VdF, TFE, and HFP (initial monomers) at a molar ratio of vinylidene fluoride [VDF] / tetrafluoroethylene [TFE] / hexafluoropropylene [HFP] (=19 / 11 / 70 mol%) and an internal pressure of 2.03 MPaG.

[0732] Next, nitrogen gas was used to pressurize an aqueous solution of polymerization initiator, prepared by dissolving 0.030 g of ammonium persulfate (APS) in deionized water, to initiate the reaction. As polymerization proceeded, when the internal pressure decreased to 2.00 MPaG, a mixed monomer of VdF / TFE / HFP (=50 / 20 / 30 mol%) was added while maintaining a constant internal pressure of 2.03 MPaG.

[0733] When an additional 10g of mixed monomers was added, 2.45g of diiodide compound I(CF2)4I was pressurized in with nitrogen gas.

[0734] Two hours and six hours after the start of polymerization, 0.03 g of APS was injected into the aqueous solution of polymerization initiator under nitrogen pressure. Nine hours later, 0.015 g of APS was injected into the aqueous solution of polymerization initiator under nitrogen pressure.

[0735] At the point where 500g of mixed monomers was added, stirring was stopped, and the pressure was released until the polymerization tank reached atmospheric pressure. The polymerization tank was then cooled to obtain an aqueous dispersion. The polymer adhesion rate, solids concentration of the aqueous dispersion, mass of the aqueous dispersion, average particle size, and particle number are shown in Table 1.

[0736] An aqueous aluminum sulfate solution was added to the above aqueous dispersion for precipitation. The precipitate was washed with water and dried to obtain a fluorinated elastomer. The Mooney viscosity of the fluorinated elastomer was ML1+10 (100°C) = 50.4. The copolymer composition was investigated by NMR analysis, and the results were VdF / TFE / HFP = 53 / 23 / 24 (mol%). Furthermore, the iodine content of the fluorinated elastomer and the amount of -CH2I structure relative to 100 mol% of the -CH2- structure are shown in Table 1.

[0737] Example 2

[0738] Add 1500g of deionized water, 0.015g of sodium p-styrene sulfonate, and 0.750g of a 10% (w / w) aqueous solution of CH2=CF-CF2OCF(CF3)COONH4 to a 3L SUS polymerization tank. Seal the polymerization tank and purge the system with nitrogen to remove oxygen. Heat the polymerization tank to 80°C and, under stirring, force in VdF, TFE, and HFP (initial monomers) at a molar ratio of vinylidene fluoride [VdF] / tetrafluoroethylene [TFE] / hexafluoropropylene [HFP] (=19 / 11 / 70 mol%) and an internal pressure of 2.03 MPaG.

[0739] Next, nitrogen gas was used to pressurize an aqueous solution of polymerization initiator, prepared by dissolving 0.030 g of ammonium persulfate (APS) in deionized water, to initiate the reaction. As polymerization proceeded, when the internal pressure decreased to 2.00 MPaG, a mixed monomer of VdF / TFE / HFP (=50 / 20 / 30 mol%) was added while maintaining a constant internal pressure of 2.03 MPaG.

[0740] When an additional 10g of mixed monomers was added, 2.45g of diiodide compound I(CF2)4I was pressurized in with nitrogen gas.

[0741] 3.0 hours and 6.0 hours after the start of polymerization, 0.030 g of APS polymerization initiator aqueous solution was injected under nitrogen pressure.

[0742] At the point where 500g of mixed monomers was added, stirring was stopped, and the pressure was released until the polymerization tank reached atmospheric pressure. The polymerization tank was then cooled to obtain an aqueous dispersion. The polymer adhesion rate, solids concentration of the aqueous dispersion, mass of the aqueous dispersion, average particle size, and particle number are shown in Table 1.

[0743] An aqueous aluminum sulfate solution was added to the above aqueous dispersion for precipitation. The precipitate was washed with water and dried to obtain a fluorinated elastomer. The Mooney viscosity of the fluorinated elastomer was ML1+10 (100°C) = 53.5. The copolymer composition was investigated by NMR analysis, and the results were VdF / TFE / HFP = 53 / 21 / 26 (mol%). Furthermore, the iodine content of the fluorinated elastomer and the amount of -CH2I structure relative to 100 mol% of the -CH2- structure are shown in Table 1.

[0744] [Table 1]

[0745] Table 1

[0746]

[0747] Crosslinking characteristics

[0748] The fluorinated elastomers obtained above were compounded according to the proportions shown in Table 2 to obtain a fluorinated elastomer composition. For the obtained fluorinated elastomer composition, a crosslinking curve was determined using a rubber vulcanization tester MDRH2030 (manufactured by M&K) during compression crosslinking, and the minimum viscosity (ML), maximum torque level (MH), induction time (T10), and positive vulcanization time (T90) were determined. Furthermore, the fluorinated elastomer composition was crosslinked by compression crosslinking and subsequent heat crosslinking, thereby obtaining crosslinked molded sheets.

[0749] Mixing method: Roller mixing

[0750] Compression crosslinking: 10 minutes at 160℃

[0751] Heating crosslinking: 180℃ for 4 hours

[0752] The materials shown in Table 2 are as follows.

[0753] MT Carbon: Thermax N-990, manufactured by Cancarb.

[0754] TAIC: Triallyl isocyanurate, manufactured by TAIC Japan Chemical Co., Ltd.

[0755] PERHEXA25B: 2,5-Dimethyl-2,5-di(tert-butylperoxy)hexane, manufactured by Nippon Oil Company.

[0756] Normal physical properties

[0757] Using cross-linked molded sheets, dumbbell-shaped test pieces were made according to JIS K6251. The 100% modulus (M100), tensile strength at break (TB), and elongation at break (EB) of the prepared test pieces were measured under normal conditions.

[0758] hardness

[0759] In the same manner as above, dumbbell-shaped test pieces were made, and the hardness (Shore A) of the test pieces was measured according to JIS K6253 (peak, 1 second, 3 seconds).

[0760] Compression permanent deformation

[0761] Using a fluorinated elastomer composition, O-rings (P24 size) were fabricated by compression crosslinking and thermal crosslinking under the above conditions. The compression set of the fabricated O-rings was measured according to JIS K6262 at 200°C for 72 hours and a compression ratio of 25%.

[0762] Thermal aging test

[0763] Cross-linked molded sheets were used to prepare dumbbell-shaped test pieces. After heat-treating the test pieces at 250°C for 72 hours, the 100% modulus (M100), tensile strength at break (TB), elongation at break (EB), and hardness of the heat-treated test pieces were measured using the method described above. The rates of change of M100, TB, and EB of the heat-treated test pieces relative to their normal physical properties are shown in Table 2. Additionally, the difference in hardness (Shore A change) of the test pieces before and after heat treatment is shown in Table 2.

[0764] The results are shown in Table 2.

[0765] [Table 2]

[0766] Table 2

[0767]

Claims

1. A method for producing an aqueous dispersion of a fluorine-containing elastomer, which polymerizes a fluorine-containing monomer in the presence of a compound (1) having an aromatic ring, a hydrophilic group, and an unsaturated double bond, and an aqueous medium, thereby producing an aqueous dispersion of a fluorine-containing elastomer having -CH2- in the main chain, wherein, The compound (1) is at least one selected from the group consisting of compounds represented by general formulae (1-1) to (1-4), and the amount of the compound (1) is 3 to 5000 mass ppm with respect to the aqueous medium, General formula (1-1): [Chemical formula 23] General formula (1-2): [Chemical formula 24] General formula (1-3): [Chemical formula 25] General formula (1-4): [Chemical formula 26] In each formula, ring A and ring B are aromatic rings with or without a substituent; R 1 ~R 3 each independently H, a halogen atom, an alkyl group or a group represented by -R 4 -Z, in which at least one hydrogen atom bonded to a carbon atom in the alkyl group can be substituted with a group represented by -R 4 -Z. R 4 is a single bond or alkylene; R 5 is a single bond or alkylene; x is an integer of 1 or more; Z is -SO3M, -OSO3M, -COOM, -P(=O)(OM)2, -OP(O)(OM)2, -B(OM)2, or -OB(OM)2; M is H, a metal atom, NR 6 4. imidazolium with or without substituents, pyridinium with or without substituents, or phosphonium with or without substituents; R 6 independently H or an organic group, R 6 Any two of R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14, R15, R16, R17 2. The production method according to claim 1, wherein Ring A is represented by any one of the following formulae, [Chemical formula 27] The curved line indicates a bonding position; in any of the aromatic rings, a hydrogen atom bonded to a carbon atom can be substituted with a substituent.

3. The production method according to claim 1 or 2, wherein Ring B is represented by any one of the following formulae, [Chemical formula 28] The curved line indicates a bonding position; in any of the aromatic rings, a hydrogen atom bonded to a carbon atom can be substituted with a substituent.

4. The production method as claimed in claim 1 or 2, wherein, The compound (1) has 6 to 30 carbon atoms.

5. The production method as claimed in claim 1 or 2, wherein, After adding the compound (1) to the polymerization system, a polymerization initiator is added, thereby initiating polymerization of the fluorine-containing monomer.

6. The production method as claimed in claim 1 or 2, wherein, The fluorine-containing monomer is vinylidene fluoride or tetrafluoroethylene.

7. The production method as claimed in claim 1 or 2, wherein, The fluorine-containing monomer is vinylidene fluoride.

8. The production method as claimed in claim 1 or 2, wherein, The fluorine-containing monomer is further polymerized in the presence of a fluorine-containing compound (A) represented by general formula (A), Formula (A): CX i X k =CX j R a -(CZ 1 Z 2 ) k -Y 3 wherein X i , X j and X k are each independently F, Cl, H or CF3; Y 3 is a hydrophilic group; R a is a linking group; Z 1 and Z 2 each independently H, F or CF3; k is 0 or 1; wherein at least one of X i , X k , X j , R a , Z 1 , and Z 2 comprises F; wherein k is 0, R a is a linking group other than a single bond.

9. The production method as claimed in claim 1 or 2, wherein, The fluorine-containing monomer is further polymerized in the presence of a chain transfer agent.

10. The production method as claimed in claim 1 or 2, wherein, The fluorine-containing monomer is polymerized at 10 to 120°C.

11. The production method as claimed in claim 1 or 2, wherein, The fluorine-containing monomer is polymerized at 0.5 to 10 MPaG.

12. The production method as claimed in claim 1 or 2, wherein, The fluorine-containing elastomer has a Mooney viscosity ML1+10 at 100°C of 10 to 130.

13. The production method as claimed in claim 1 or 2, wherein, The fluorine-containing elastomer has an average particle diameter of 500 nm or less.

14. A fluorine-containing elastomer containing monomer units of a compound (1) having an aromatic ring, a hydrophilic group, and an unsaturated double bond, and having -CH2- in the main chain, the compound (1) being at least one selected from the group consisting of compounds represented by general formulae (1-1) to (1-4), and the content of the monomer units based on the compound (1) in the fluorine-containing elastomer being 0.0009 to 1.5 mass% with respect to the total monomer units, General formula (1-1): [Chemical formula 23] General formula (1-2): [Chemical formula 24] General formula (1-3): [Chemical formula 25] General formula (1-4): [Chemical formula 26] In each formula, ring A and ring B are aromatic rings with or without a substituent; R 1 ~R 3 each independently H, a halogen atom, an alkyl group or a group represented by -R 4 -Z, in which at least one hydrogen atom bonded to a carbon atom in the alkyl group can be substituted with a group represented by -R 4 -Z. R 4 is a single bond or alkylene; R 5 is a single bond or alkylene; x is an integer of 1 or more; Z is -SO3M, -OSO3M, -COOM, -P(=O)(OM)2, -OP(O)(OM)2, -B(OM)2, or -OB(OM)2; M is H, a metal atom, NR 6 4. imidazolium with or without substituents, pyridinium with or without substituents, or phosphonium with or without substituents; R 6 independently H or an organic group, R 6 any 2 of which can be bonded to one another to form a ring.

15. A fluorine-containing elastomer aqueous dispersion containing the fluorine-containing elastomer according to claim 14 and an aqueous medium.

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