Method for producing aqueous dispersion of fluorine-containing elastomer and composition

Abstract

The present invention provides a method for producing a fluorine-containing elastomer aqueous dispersion, wherein an aqueous dispersion of a fluorine-containing elastomer is produced by polymerizing a fluorine-containing monomer in the presence of an aqueous medium and a polymer (1) that contains a polymerization unit (1) based on a monomer (1) that is represented by general formula (1).　(1): CF2=CF-R-CZ1Z2-COOM (In the formula, R represents a linking group; each of Z1 and Z2 independently represents F or CF3; M represents H, a metal atom, NR7 4, an optionally substituted imidazolium, an optionally substituted pyridinium or an optionally substituted phosphonium; and R7 represents H or an organic group.)

Description

Technical Field

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

Background Art

[0002] Patent Document 1 describes that an oligomeric fluorosulfinic acid compound and / or an ethylenically unsaturated fluorosulfinic acid compound of a polymerization monomer can be used in the aqueous emulsion polymerization of at least one ethylenically unsaturated fluoromonomer, for example, a fluorinated olefin, to produce a fluoropolymer having a partially or fully fluorinated main chain.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present disclosure is to provide a method for producing an aqueous dispersion of a fluorine-containing elastomer that can generate a sufficient number of fluorine-containing elastomer particles at a sufficient polymerization rate while suppressing the adhesion of the fluorine-containing elastomer to the polymerization tank.

Means for Solving the Problems

[0005] According to the present disclosure, there is provided a method for producing an aqueous dispersion of a fluorine-containing elastomer by polymerizing a fluorine-containing monomer in the presence of a polymer (1) containing a polymerization unit (1) based on a monomer (1) represented by the general formula (1) and an aqueous medium. CF2=CF-R-CZ 1 Z 2 -COOM (1) (In the formula, R is a linking group, and Z1 and Z 2 is, independently of one another, F or CF3, and M is H, a metal atom, NR 7 4, an optionally substituted imidazolium, an optionally substituted pyridinium or an optionally substituted phosphonium, and R 7 is H or an organic group.)

[0006] In the production method of the present disclosure, it is preferable that the monomer (1) is the monomer (2) represented by the general formula (2). CF2=CF(-O-Rf-COOM) (2) (In the formula, Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms, or a fluorine-containing alkylene group having an ether bond or a keto group and having 2 to 100 carbon atoms, and M is as described above.) In the production method of the present disclosure, it is preferable that the weight average molecular weight of the polymer (1) is 1.4×10 4 or more. In the production method of the present disclosure, it is preferable that the content of the polymerization unit (1) is 50 mol% or more based on all the polymerization units constituting the polymer (1). In the production method of the present disclosure, it is preferable that the addition amount of the polymer (1) is 0.0001 to 20% by mass based on 100% by mass of the aqueous medium. In the production method of the present disclosure, the polymerization of the fluorine-containing monomer is carried out in the presence of a polymerization initiator, and it is preferable that the addition amount of the polymerization initiator is 0.00001 to 10% by mass based on 100% by mass of the fluorine-containing monomer. In the production method of the present disclosure, it is preferable that the polymerization of the fluorine-containing monomer is carried out substantially in the absence of a fluorine-containing surfactant. In the production method of the present disclosure, it is preferable that the fluorine-containing monomer is vinylidene fluoride or tetrafluoroethylene. In the production method of the present disclosure, it is preferable that the fluorine-containing monomer is vinylidene fluoride. In the production method of the present disclosure, it is preferable that the fluorine-containing elastomer contains -CH2- in the main chain.

[0007] Further, according to the present disclosure, there is provided a composition containing a fluorine-containing elastomer and a polymer (1) containing a polymerization unit (1) based on the monomer (1) represented by the general formula (1). CF2=CF-R-CZ 1 Z 2 -COOM (1) (In the formula, R is a linking group, and Z 1 and Z 2 are each independently F or CF3, and M is H, a metal atom, NR 7 4, an optionally substituted imidazolium, an optionally substituted pyridinium or an optionally substituted phosphonium, and R 7 is H or an organic group.)

[0008] In the composition of the present disclosure, it is preferable that the monomer (1) is the monomer (2) represented by the general formula (2). CF2=CF(-O-Rf-COOM) (2) (In the formula, Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms, or a fluorine-containing alkylene group having an ether bond or a keto group and having 2 to 100 carbon atoms, and M is as described above.)

[0009] In the composition of the present disclosure, it is preferable that the weight average molecular weight of the polymer (1) is 1.4×10 4 or more. In the composition of the present disclosure, it is preferable that the content of the polymerization unit (1) is 50 mol% or more based on all the polymerization units constituting the polymer (1). In the composition of the present disclosure, it is preferable that the content of the polymer (1) is 0.00001 to 20% by mass based on the fluorine-containing elastomer. The composition of the present disclosure is preferably an aqueous dispersion. In the composition of the present disclosure, it is preferable that the solid content concentration of the aqueous dispersion is 5 to 50% by mass based on the aqueous dispersion. The composition of the present disclosure preferably does not substantially contain a fluorine-containing surfactant. In the composition of the present disclosure, it is preferable that the fluorine-containing elastomer contains vinylidene fluoride units or tetrafluoroethylene units. In the composition of the present disclosure, it is preferable that the fluorine-containing elastomer contains vinylidene fluoride units. In the composition of the present disclosure, it is preferable that the fluorine-containing elastomer contains -CH2- in the main chain.

Advantages of the Invention

[0010] According to the present disclosure, it is possible to provide a method for producing an aqueous dispersion of a fluorine-containing elastomer that can generate a sufficient number of fluorine-containing elastomer particles at a sufficient polymerization rate while suppressing the adhesion of the fluorine-containing elastomer to the polymerization tank.

Modes for Carrying Out the Invention

[0011] In the present disclosure, the fluorine-containing elastomer is an amorphous fluoropolymer. "Amorphous" means that the size of the melting peak (ΔH) appearing in the differential scanning calorimetry [DSC] (heating rate 10 °C / min) or differential thermal analysis [DTA] (heating rate 10 °C / min) of the fluoropolymer is 4.5 J / g or less. The fluorine-containing elastomer exhibits elastomeric properties by crosslinking. The elastomeric properties mean the property that the polymer can be stretched and can retain its original length when the force required to stretch the polymer is no longer applied.

[0012] In the present disclosure, the perfluoro monomer is a monomer that does not contain a carbon atom-hydrogen atom bond in the molecule. The above perfluoro monomer may be a monomer in which some of the fluorine atoms bonded to the carbon atom are substituted with chlorine atoms in addition to the carbon atom and fluorine atoms, or may have a nitrogen atom, an oxygen atom, a sulfur atom, a phosphorus atom, a boron atom, or a silicon atom in addition to the carbon atom. It is preferable that the above perfluoro monomer is a monomer in which all hydrogen atoms are substituted with fluorine atoms. The above perfluoro monomer does not include a monomer that gives a crosslinkable group.

[0013] The monomer that provides a crosslinking site is a monomer (cure site monomer) that provides a crosslinking site for forming a crosslink by a crosslinking agent to a fluoropolymer. The monomer that provides a crosslinking site includes a monomer that provides a crosslinkable group.

[0014] In the present disclosure, the content of each monomer unit constituting the fluorine-containing elastomer can be calculated by appropriately combining NMR, FT-IR, elemental analysis, and X-ray fluorescence analysis according to the type of monomer.

[0015] In the present disclosure, the "organic group" means a group containing one or more carbon atoms, or a group formed by removing one hydrogen atom from an organic compound. Examples of the "organic group" are an alkyl group which may have one or more substituents, an alkenyl group which may have one or more substituents, an alkynyl group which may have one or more substituents, a cycloalkyl group which may have one or more substituents, a cycloalkenyl group which may have one or more substituents, a cycloalkadienyl group which may have one or more substituents, an aryl group which may have one or more substituents, an aralkyl group which may have one or more substituents, a non-aromatic heterocyclic group which may have one or more substituents, a heteroaryl group which may have one or more substituents, a cyano group, a formyl group, RaO-, RaCO-, RaSO2-, RaCOO-, RaNRaCO-, RaCONRa-, RaOCO-, RaOSO2-, and, RaNRbSO2- (In these formulas, each Ra independently represents an alkyl group which may have one or more substituents, an alkenyl group which may have one or more substituents, an alkynyl group which may have one or more substituents, a cycloalkyl group which may have one or more substituents, a cycloalkenyl group which may have one or more substituents, a cycloalkadienyl group which may have one or more substituents, an aryl group which may have one or more substituents, an aralkyl group which may have one or more substituents, a non-aromatic heterocyclic group which may have one or more substituents, or a heteroaryl group which may have one or more substituents, and each Rb independently represents H or an alkyl group which may have one or more substituents.) is included. As the above organic group, an alkyl group which may have one or more substituents is preferred.

[0016] In the present disclosure, a "substituent" means a group that can be substituted. Examples of the "substituent" include an aliphatic group, an aromatic group, a heterocyclic group, an acyl group, an acyloxy group, an acylamino group, an aliphatic oxy group, an aromatic oxy group, a heterocyclic oxy group, an aliphatic oxycarbonyl group, an aromatic oxycarbonyl group, a heterocyclic oxycarbonyl group, a carbamoyl group, an aliphatic sulfonyl group, an aromatic sulfonyl group, a heterocyclic sulfonyl group, an aliphatic sulfonyloxy group, an aromatic sulfonyloxy group, a heterocyclic sulfonyloxy group, a sulfamoyl group, an aliphatic sulfonamide group, an aromatic sulfonamide group, a heterocyclic sulfonamide group, an amino group, an aliphatic amino group, an aromatic amino group, a heterocyclic amino group, an aliphatic oxycarbonylamino group, an aromatic oxycarbonylamino group, a heterocyclic oxycarbonylamino group, an aliphatic sulfinyl group, an aromatic sulfinyl group, an aliphatic thio group, an aromatic thio group, a hydroxy group, a cyano group, a sulfo group, a carboxy group, an aliphatic oxyamino group, an aromatic oxyamino group, a carbamoylamino group, a sulfamoylamino group, a halogen atom, a sulfamoylcarbamoyl group, a carbamoylsulfamoyl group, a di-aliphatic oxyphosphinyl group, and a di-aromatic oxyphosphinyl group.

[0017] The above aliphatic group may be saturated or unsaturated, and may also have a hydroxy group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the above aliphatic group include an alkyl group having 1 to 8, preferably 1 to 4 carbon atoms in total, such as a methyl group, an ethyl group, a vinyl group, a cyclohexyl group, a carbamoylmethyl group, etc.

[0018] The above aromatic group may have, for example, a nitro group, a halogen atom, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the above aromatic group include an aryl group having 6 to 12 carbon atoms, preferably 6 to 10 total carbon atoms, such as a phenyl group, a 4-nitrophenyl group, a 4-acetylaminophenyl group, a 4-methanesulfonylphenyl group, etc.

[0019] The above heterocyclic group may have a halogen atom, a hydroxy group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the above heterocyclic group include a 5- to 6-membered heterocycle having 2 to 12 total carbon atoms, preferably 2 to 10, such as a 2-tetrahydrofuryl group, a 2-pyrimidyl group, etc.

[0020] The above acyl group may have an aliphatic carbonyl group, an arylcarbonyl group, a heterocyclic carbonyl group, a hydroxy group, a halogen atom, an aromatic group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the above acyl group include an acyl group having 2 to 8 total carbon atoms, preferably 2 to 4, such as an acetyl group, a propanoyl group, a benzoyl group, a 3-pyridinecarbonyl group, etc.

[0021] The above acylamino group may have an aliphatic group, an aromatic group, a heterocyclic group, etc., and may have, for example, an acetylamino group, a benzoylamino group, a 2-pyridinecarbonylamino group, a propanoylamino group, etc. Examples of the above acylamino group include an acylamino group having 2 to 12 total carbon atoms, preferably 2 to 8, an alkylcarbonylamino group having 2 to 8 total carbon atoms, such as an acetylamino group, a benzoylamino group, a 2-pyridinecarbonylamino group, a propanoylamino group, etc.

[0022] The above aliphatic oxycarbonyl group may be saturated or unsaturated, and may also have a hydroxy group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the above aliphatic oxycarbonyl group include an alkoxycarbonyl group having 2 to 8 carbon atoms in total, preferably 2 to 4 carbon atoms, such as a methoxycarbonyl group, an ethoxycarbonyl group, a (t)-butoxycarbonyl group, etc.

[0023] The above carbamoyl group may have an aliphatic group, an aromatic group, a heterocyclic group, etc. Examples of the above carbamoyl group include an unsubstituted carbamoyl group, an alkylcarbamoyl group having 2 to 9 carbon atoms in total, preferably an unsubstituted carbamoyl group, an alkylcarbamoyl group having 2 to 5 carbon atoms in total, such as an N-methylcarbamoyl group, an N,N-dimethylcarbamoyl group, an N-phenylcarbamoyl group, etc.

[0024] The above aliphatic sulfonyl group may be saturated or unsaturated, and may also have a hydroxy group, an aromatic group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the above aliphatic sulfonyl group include an alkylsulfonyl group having 1 to 6 carbon atoms in total, preferably 1 to 4 carbon atoms in total, such as a methanesulfonyl group, etc.

[0025] The above aromatic sulfonyl group may have a hydroxy group, an aliphatic group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the above aromatic sulfonyl group include an arylsulfonyl group having 6 to 10 carbon atoms in total, such as a benzenesulfonyl group, etc.

[0026] The above amino group may have an aliphatic group, an aromatic group, a heterocyclic group, etc.

[0027] The acylamino group may have, for example, an acetylamino group, a benzoylamino group, a 2-pyridinecarbonylamino group, a propanoylamino group, or the like. Examples of the acylamino group include an acylamino group having 2 to 12 carbon atoms in total, preferably an acylamino group having 2 to 8 carbon atoms in total, more preferably an alkylcarbonylamino group having 2 to 8 carbon atoms in total, such as an acetylamino group, a benzoylamino group, a 2-pyridinecarbonylamino group, a propanoylamino group, or the like.

[0028] The aliphatic sulfonamide group, aromatic sulfonamide group, and heterocyclic sulfonamide group may be, for example, a methanesulfonamide group, a benzenesulfonamide group, a 2-pyridinesulfonamide group, or the like.

[0029] The sulfamoyl group may have an aliphatic group, an aromatic group, a heterocyclic group, or the like. Examples of the sulfamoyl group include a sulfamoyl group, an alkylsulfamoyl group having 1 to 9 carbon atoms in total, a dialkylsulfamoyl group having 2 to 10 carbon atoms in total, an arylsulfamoyl group having 7 to 13 carbon atoms in total, a heterocyclic sulfamoyl group having 2 to 12 carbon atoms in total, more preferably a sulfamoyl group, an alkylsulfamoyl group having 1 to 7 carbon atoms in total, a dialkylsulfamoyl group having 3 to 6 carbon atoms in total, an arylsulfamoyl group having 6 to 11 carbon atoms in total, a heterocyclic sulfamoyl group having 2 to 10 carbon atoms in total, such as a sulfamoyl group, a methylsulfamoyl group, an N,N-dimethylsulfamoyl group, a phenylsulfamoyl group, a 4-pyridinesulfamoyl group, or the like.

[0030] The aliphatic oxy group may be saturated or unsaturated, and may have, for example, a methoxy group, an ethoxy group, an i-propyloxy group, a cyclohexyloxy group, a methoxyethoxy group, or the like. Examples of the aliphatic oxy group include an alkoxy group having 1 to 8 carbon atoms in total, preferably 1 to 6 carbon atoms in total, such as a methoxy group, an ethoxy group, an i-propyloxy group, a cyclohexyloxy group, a methoxyethoxy group, or the like.

[0031] The above aromatic amino group and heterocyclic amino group may have an aliphatic group, an aliphatic oxy group, a halogen atom, a carbamoyl group, a heterocyclic group condensed with the aryl group, an aliphatic oxycarbonyl group, preferably an aliphatic group having 1 to 4 carbon atoms in total, an aliphatic oxy group having 1 to 4 carbon atoms in total, a halogen atom, a carbamoyl group having 1 to 4 carbon atoms in total, a nitro group, and an aliphatic oxycarbonyl group having 2 to 4 carbon atoms in total.

[0032] The above aliphatic thio group may be saturated or unsaturated, and examples thereof include an alkylthio group having 1 to 8 carbon atoms in total, more preferably an alkylthio group having 1 to 6 carbon atoms in total, such as a methylthio group, an ethylthio group, a carbamoylmethylthio group, and a t-butylthio group.

[0033] The above carbamoylamino group may have an aliphatic group, an aryl group, a heterocyclic group, etc. Examples of the above carbamoylamino group include a carbamoylamino group, an alkylcarbamoylamino group having 2 to 9 carbon atoms in total, a dialkylcarbamoylamino group having 3 to 10 carbon atoms in total, an arylcarbamoylamino group having 7 to 13 carbon atoms in total, a heterocyclic carbamoylamino group having 3 to 12 carbon atoms in total, preferably a carbamoylamino group, an alkylcarbamoylamino group having 2 to 7 carbon atoms in total, a dialkylcarbamoylamino group having 3 to 6 carbon atoms in total, an arylcarbamoylamino group having 7 to 11 carbon atoms in total, a heterocyclic carbamoylamino group having 3 to 10 carbon atoms in total, for example, a carbamoylamino group, a methylcarbamoylamino group, an N,N-dimethylcarbamoylamino group, a phenylcarbamoylamino group, a 4-pyridinecarbamoylamino group, etc.

[0034] In the present disclosure, a range represented by endpoints includes all numerical values included in that range (for example, 1 to 10 includes 1.4, 1.9, 2.33, 5.75, 9.98, etc.).

[0035] In the present disclosure, the description of "at least 1" includes all numerical values of 1 or more (for example, 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.).

[0036] Hereinafter, specific embodiments of the present disclosure will be described in detail, but the present disclosure is not limited to the following embodiments.

[0037] The present disclosure relates to a method for producing an aqueous dispersion of a fluorine-containing elastomer by polymerizing a fluorine-containing monomer in the presence of a polymer (1) containing a polymerization unit (1) based on a monomer (1) represented by the general formula (1) and an aqueous medium. CF2=CF-R-CZ 1 Z 2 -COOM (1) (In the formula, R is a linking group, and Z 1 and Z 2 are each independently F or CF3, M is H, a metal atom, NR 7 4, an optionally substituted imidazolium, an optionally substituted pyridinium or an optionally substituted phosphonium, and R 7 is H or an organic group.)

[0038] Since the production method of the present disclosure polymerizes a fluorine-containing monomer in the presence of a polymer (1) and an aqueous medium, it is possible to generate a sufficient number of fluorine-containing elastomer particles at a sufficient polymerization rate while suppressing the adhesion of the fluorine-containing elastomer to the polymerization tank.

[0039] In the production method of the present disclosure, one or more monomers can be used as the monomer (1) represented by the general formula (1).

[0040] R is a linking group. In the present disclosure, a "linking group" is a divalent linking group. The linking group may be a single bond, preferably contains at least one carbon atom, and the number of carbon atoms may be 2 or more, may be 4 or more, may be 8 or more, may be 10 or more, and may be 20 or more. The upper limit is not limited, for example, it may be 100 or less, and may be 50 or less.

[0041] The linking group may be linear or branched, cyclic or acyclic, saturated or unsaturated, substituted or unsubstituted, and optionally contains one or more heteroatoms selected from the group consisting of sulfur, oxygen, and nitrogen, and optionally contains one or more functional groups selected from the group consisting of ester, amide, sulfonamide, carbonyl, carbonate, urethane, urea, and carbamate. The above linking group may not contain a carbon atom and may be a chain heteroatom such as oxygen, sulfur, or nitrogen.

[0042] R is preferably, for example, a chain heteroatom such as oxygen, sulfur, nitrogen, or a divalent organic group.

[0043] When R is a divalent organic group, the hydrogen atom bonded to the carbon atom may be replaced by a halogen other than fluorine, such as chlorine, and may or may not contain a double bond. Also, R may be either linear or branched, and may be either cyclic or acyclic. Further, R may contain a functional group (for example, ester, ether, ketone (keto group), amine, halide, etc.).

[0044] R may also be a non-fluorinated divalent organic group or a partially fluorinated or perfluorinated divalent organic group.

[0045] R may be, for example, a hydrocarbon group in which no fluorine atom is bonded to a carbon atom, a hydrocarbon group in which some of the hydrogen atoms bonded to a carbon atom are substituted with fluorine atoms, or a hydrocarbon group in which all of the hydrogen atoms bonded to a carbon atom are substituted with fluorine atoms, and these may contain an oxygen atom, a double bond, or a functional group.

[0046] R is preferably a hydrocarbon group having 1 to 100 carbon atoms which may contain an ether bond or a keto group, and some or all of the hydrogen atoms bonded to the carbon atoms of the hydrocarbon group may be substituted with fluorine.

[0047] Preferably, R is -(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 -,-O[(CF2) a -O] b -[(CF2) c -O] d -,-O-[CF2CF(CF3)O] a -(CF2) b -,-O-(CF2) a -O-[CF(CF3)CF2O] b -O-,-O-[CF2CF(CF3)O] a -(CF2) b -O-,-O-[CF2CF(CF3)O] a -(CF2) b ​​-O-[CF(CF3)CF2O] c -O-, -[CF2CF(CF3)O] a -, -[CF(CF3)CF2O] a -, -(CF2) a -O-[CF(CF3)CF2O] a -, -(CF2) a -O-[CF(CF3)CF2O] a -(CF2) b -, -[CF2CF(CF3)] a -CO-(CF2) b - and at least one selected from combinations thereof. Wherein a, b, c and d are each independently at least 1 or more. a, b, c and d may each independently be 2 or more, 3 or more, 4 or more, 10 or more, 20 or more. The upper limit of a, b, c and d is, for example, 100. More preferably as R, at least one selected from -O-CF2-, -O-CF2CF2-, -O-CF2CF2-O-, -O-CF2CF2CF2-, -O-CF2CF2CF2-O-, -O-CF2CF(CF3)-O-, -O-CF2CF2-O-CF(CF3)CF2-O-, -O-CF2CF(CF3)-O-CF2CF2-O-, and -O-CF2CF(CF3)-O-CF2-.

[0048] As R, the general formula (r1): -CF2-O-(CX 6 2) e -{O-CF(CF3)} f -(O) g - (r1) (Wherein X 6 is each independently H, F or CF3, e is an integer from 0 to 3, f is an integer from 0 to 3, and g is 0 or 1), and the divalent group represented by the general formula (r2): -CF2-O-(CX 7 2) e -(O) g - (r2) (Wherein X 7is independently H, F, or CF3, e is an integer from 0 to 3, and g is 0 or 1), a divalent group represented by is more preferable.

[0049] Specific examples suitable as R include -CF2-O-CF2-, -CF2-O-CH2-, -CF2-O-CH2CF2-, -CF2-O-CF2CF2-, -CF2-O-CF2CH2-, -CF2-O-CF2CF2CH2-, -CF2-O-CF(CF3)-, -CF2-O-CF(CF3)CF2-, -CF2-O-CF(CF3)CF2-O-, -CF2-O-CF(CF3)CF2-O-CF2-, -CF2-O-CF(CF3)CH2-, and the like. Among them, R is preferably a perfluoroalkylene group which may contain an oxygen atom. Specifically, -CF2-O-, -CF2-O-CF2-, -CF2-O-CF2CF2-, -CF2-O-CF(CF3)-, -CF2-O-CF(CF3)CF2-, -CF2-O-CF(CF3)CF2-O- are preferable.

[0050] -R-CZ in the general formula (1) 1 Z 2 - is preferably represented by the general formula (s1): -CF2-O-(CX 6 2) e -{O-CF(CF3)} f -(O) g -CZ 1 Z 2 - (s1) (In the formula, X 6 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, and Z 1 and Z 2 are each independently F or CF3), and in the formula (s1), Z 1 and Z 2 are more preferably such that one is F and the other is CF3.

[0051] Also, in the general formula (1), -R-CZ 1 Z 2 - is preferably represented by the general formula (s2): -CF2-O-(CX 7 2) e -(O) g -CZ 1 Z 2 - (s2) (wherein X 7 is independently H, F or CF3, e is an integer from 0 to 3, g is 0 or 1, and Z 1 and Z 2 are each independently F or CF3), and in formula (s2), it is more preferable that one of Z 1 and Z 2 is F and the other is CF3.

[0052] -R-CZ 1 Z 2- includes -O-CF2CF2-, -O-CF2CF2CF2-, -O-CF2CF2CF2CF2-, -O-CF2CF(CF3)-O-CF2-, -O-CF2CF(CF3)-O-CF2CF2-, -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)-, or -CF2-O-CF(CF3)CF2-O-C(CF3)2-; -O-CF2CF2-, -O-CF2CF2CF2-, -O-CF2CF2CF2CF2-, -O-CF2CF(CF3)-O-CF2-, -O-CF2CF(CF3)-O-CF2CF2-, -CF2-O-CF(CF3)-, -CF2-O-CF2-CF(CF3)-, -CF2-O-CF2CF2-CF(CF3)-, -CF2-O-CF(CF3)-CF(CF3)-, -CF2-O-CF(CF3)CF2-CF(CF3)-, or -CF2-O-CF(CF3)CF2-O-CF(CF3)- is more preferred; -O-CF2CF2-, -O-CF2CF(CF3)-O-CF2CF2- is even more preferred.

[0053] The polymer (1) is preferably highly fluorinated. For example, it is preferred that 80% or more, 90% or more, 95% or more, or 100% of the C-H bonds in the polymer (1) are replaced by C-F bonds.

[0054] The monomer (1) and the polymer (1) preferably have a C-F bond and no C-H bond, except for -COOM. That is, in the general formula (1), R is preferably a perfluoroalkylene group having 1 or more carbon atoms. The perfluoroalkylene group may be either linear or branched, either cyclic or acyclic, and may contain at least one catenary heteroatom. The number of carbon atoms of the perfluoroalkylene group may be 2 to 20, or may be 4 to 18.

[0055] The monomer (1) and the polymer (1) may be partially fluorinated. That is, the monomer (1) and the polymer (1) preferably have at least one hydrogen atom bonded to a carbon atom and at least one fluorine atom bonded to a carbon atom.

[0056] M is H, a metal atom, NR 7 4, an imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent, and R 7 is H or an organic group.

[0057] Examples of the metal atom include alkali metals (Group 1) and alkaline earth metals (Group 2), and Na, K, or Li is preferred.

[0058] As M, H, a metal atom, or NR 7 4 is preferred, H, an alkali metal (Group 1), an alkaline earth metal (Group 2), or NR 7 4 is more preferred, H, Na, K, Li, or NH4 is even more preferred, H, Na, K, or NH4 is even more preferred, and H or NH4 is particularly preferred.

[0059] The monomer (1) is preferably the monomer (2) represented by the general formula (2). The polymer (1) is preferably the polymer (2) containing the polymerization unit (2) based on the monomer (2) represented by the general formula (2). CF2=CF(-O-Rf-COOM) (2) (In the formula, Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms, or a fluorine-containing alkylene group having an ether bond or a keto group and having 2 to 100 carbon atoms, and M is as described above.)

[0060] The polymer (2) may be a homopolymer of the monomer represented by the general formula (2) or a copolymer with other monomers.

[0061] In the general formula (2), the above Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms, a fluorine-containing alkylene group having an ether bond and having 2 to 100 carbon atoms, or a fluorine-containing alkylene group having a keto group and having 2 to 100 carbon atoms. Rf has -CZ at the terminal bonded to -COOM 1 Z 2 -(Z 1 and Z 2 as described above) may be included. The fluorine-containing alkylene group having an ether bond and having 2 to 100 carbon atoms does not include a structure in which an oxygen atom is at the terminal and is an alkylene group containing an ether bond between carbon atoms.

[0062] The number of carbon atoms of the fluorine-containing alkylene group of Rf is preferably 2 or more. Further, it is preferably 30 or less, more preferably 20 or less, still more preferably 10 or less, and particularly preferably 5 or less. Examples of the fluorine-containing alkylene group include -CF2-, -CH2CF2-, -CF2CF2-, -CF2CH2-, -CF2CF2CH2-, -CF(CF3)-, -CF(CF3)CF2-, -CF(CF3)CH2-, -CF2CF2CF2-, CF2CF2CF2CF2-, etc. The fluorine-containing alkylene group is preferably a perfluoroalkylene group, and more preferably an unbranched linear perfluoroalkylene group.

[0063] The number of carbon atoms of the fluorine-containing alkylene group having the above ether bond is preferably 3 or more. Further, the number of carbon atoms of the fluorine-containing alkylene group having the above ether bond is preferably 60 or less, more preferably 30 or less, still more preferably 12 or less, and particularly preferably 5 or less. The fluorine-containing alkylene group having the above ether bond is, for example, of the general formula: [Chem.] (wherein, Z 1 is F or CF3; Z 2 and Z 3 are each H or F; Z 4 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) is also preferably a divalent group represented by

[0064] Specific examples of the fluorine-containing alkylene group having the above ether bond include -CF(CF3)CF2 - O - CF(CF3)-, -(CF(CF3)CF2 - O) n -CF(CF3)-(wherein, n is an integer from 1 to 10), -CF(CF3)CF2 - O - CF(CF3)CH2-, -(CF(CF3)CF2 - O) n -CF(CF3)CH2-(wherein, n is an integer from 1 to 10), -CH2CF2CF2O - CH2CF2CH2-, -CF2CF2CF2O - CF2-, -CF2CF2CF2O - CF2CF2-, -CF2CF2CF2O - CF2CF2CF2-, -CF2CF2CF2O - CF2CF2CH2-, -CF2CF2O - CF2-, -CF2CF2O - CF2CH2-, etc. The fluorine-containing alkylene group having the above ether bond is preferably a perfluoroalkylene group.

[0065] The carbon number of the fluorine-containing alkylene group having the above keto group is preferably 3 or more. Also, the carbon number of the fluorine-containing alkylene group having the above keto group is preferably 60 or less, more preferably 30 or less, still more preferably 12 or less, and particularly preferably 5 or less.

[0066] Specific examples of the fluorine-containing alkylene group having the above keto group include -CF2CF(CF3)CO - CF2-, -CF2CF(CF3)CO - CF2CF2-, -CF2CF(CF3)CO - CF2CF2CF2-, -CF2CF(CF3)CO - CF2CF2CF2CF2-, etc. The fluorine-containing alkylene group having the above keto group is preferably a perfluoroalkylene group.

[0067] M is H, a metal atom, NR 7 4, an optionally substituted imidazolium, an optionally substituted pyridinium or an optionally substituted phosphonium, and R 7 is H or an organic group.

[0068] R 7 is preferably H or an organic group of C 1-10 is more preferably H or an organic group of C 1-4 is still more preferably H or an organic group of C 1-4 alkyl group.

[0069] Examples of the metal atom include alkali metals (Group 1), alkaline earth metals (Group 2), etc., and Na, K or Li is preferred.

[0070] As M, H, a metal atom or NR 7 4 is preferred, H, an alkali metal (Group 1), an alkaline earth metal (Group 2) or NR 7 4 is more preferred, H, Na, K, Li or NH4 is still more preferred, H, Na, K or NH4 is even more preferred, and H or NH4 is particularly preferred.

[0071] The monomer represented by the general formula (2) is preferably at least one selected from the group consisting of the monomers represented by the general formulas (2a), (2b), (2c), (2d), (2e), (2f) and (2g). CF2=CF-O-(CF2) n1 -COOM (2a) (In the formula, n1 represents an integer of 1 to 10. M is the same as defined above.) CF2=CF-O-(CF2C(CF3)F) n2 -COOM (2b) (In the formula, n2 represents an integer of 1 to 5. M is the same as defined above.) CF2=CF-O-(CFX 1 ) n3 -COOM (2c) (In the formula, X 1represents F or CF3, and n3 represents an integer from 1 to 10. M is the same as defined above.) CF2=CF-O-(CF2CFX 1 O) n4 -(CF2) n6 -COOM (2d) (In the formula, n4 represents an integer from 1 to 10, and n6 represents an integer from 1 to 3. M is the same as defined above.) CF2=CF-O-(CF2CF2CFX 1 O) n5 -CF2CF2CF2-COOM (2e) (In the formula, n5 represents an integer from 0 to 10, and M and X 1 are the same as defined above.) CF2=CF-O-(CF2) n7 -O-(CF2) n8 -COOM (2f) (In the formula, n7 represents an integer from 1 to 10, and n8 represents an integer from 1 to 3. M is the same as defined above.) CF2=CF[OCF2CF(CF3)] n9 O(CF2) n10 O[CF(CF3)CF2O] n11 CF(CF3)COOM (2g) (In the formula, n9 represents an integer from 0 to 5, n10 represents an integer from 1 to 8, and n11 represents an integer from 0 to 5. M is the same as defined above.)

[0072] In general formula (2a), it is preferable that the above n1 is an integer of 5 or less, and more preferably an integer of 2 or less.

[0073] Examples of the monomer represented by general formula (2a) include CF2=CF-O-CF2COOM, CF2=CF(OCF2CF2COOM), and CF2=CF(O(CF2)3COOM) (where M is the same as defined above).

[0074] In general formula (2b), it is preferable that n2 is an integer of 3 or less in terms of the dispersion stability of the resulting composition.

[0075] In general formula (2c), n3 is preferably an integer of 5 or less in terms of water solubility, and M is preferably H or NH4.

[0076] In general formula (2d), X 1 is preferably -CF3 in terms of the dispersion stability of the composition, n4 is preferably an integer of 5 or less in terms of water solubility, and M is preferably H or NH4.

[0077] Examples of the monomer represented by general formula (2d) include CF2=CFOCF2CF(CF3)OCF2CF2COOM, CF2=CFOCF2CF(CF3)OCF2COOM, and CF2=CFOCF2CF(CF3)OCF2CF2CF2COOM (wherein M represents H, NH4, or an alkali metal).

[0078] In general formula (2e), n5 is preferably an integer of 5 or less in terms of water solubility, and M is preferably H or NH4.

[0079] Examples of the monomer represented by general formula (2e) include CF2=CFOCF2CF2CF2COOM (wherein M represents H, NH4, or an alkali metal).

[0080] In general formula (2f), n7 is preferably an integer of 5 or less in terms of water solubility, and M is preferably H or NH4.

[0081] Examples of the monomer represented by general formula (2f) include CF2=CF-O-(CF2)3-O-CF2-COOM (wherein M represents H, NH4, or an alkali metal).

[0082] In general formula (2g), n9 is preferably an integer of 3 or less in terms of water solubility, n10 is preferably an integer of 3 or less, n11 is preferably an integer of 3 or less, and M is preferably H or NH4.

[0083] Examples of the monomer represented by the general formula (2g) include CF2=CFO(CF2)2OCF(CF3)COOM, CF2=CFOCF2CF2OCF(CF3)CF2OCF(CF3)COOM, CF2=CFOCF2CF(CF3)OCF2CF2OCF(CF3)COOM, CF2=CF[OCF2CF(CF3)]2O(CF2)2O[CF(CF3)CF2O]CF(CF3)COOM, CF2=CF[OCF2CF(CF3)]3O(CF2)2O[CF(CF3)CF2O]3CF(CF3)COOM (wherein M represents H, NH4 or an alkali metal).

[0084] The polymer (1) may be a homopolymer composed only of the polymerization unit (1), or may be a copolymer containing the polymerization unit (1) and a polymerization unit based on another monomer copolymerizable with the monomer (1) represented by the general formula (1). From the viewpoint of solubility in an aqueous medium, a homopolymer composed only of the polymerization unit (1) is preferred. The polymerization unit (1) may be the same or different at each occurrence, and the polymer (1) may contain polymerization units (1) based on two or more different monomers represented by the general formula (1).

[0085] As the above-mentioned other monomer, a monomer represented by the general formula CFR=CR2 (wherein R is independently H, F or a perfluoroalkyl group having 1 to 4 carbon atoms) is preferred. Further, as the other monomer, a fluorine-containing ethylenic monomer having 2 or 3 carbon atoms is preferred. Examples of the other monomer include CF2=CF2, CF2=CFCl, CH2=CF2, CFH=CH2, CFH=CF2, CF2=CFCF3, CH2=CFCF3, CH2=CHCF3, CHF=CHCF3 (E isomer), CHF=CHCF3 (Z isomer), and the like. Among them, at least one selected from the group consisting of tetrafluoroethylene (CF2=CF2), chlorotrifluoroethylene (CF2=CFCl), and vinylidene fluoride (CH2=CF2) is preferable in terms of good copolymerizability, and at least one selected from the group consisting of tetrafluoroethylene and vinylidene fluoride is more preferable. Therefore, the polymerization unit based on the above other monomer is preferably a polymerization unit based on at least one selected from the group consisting of tetrafluoroethylene and vinylidene fluoride. The polymerization unit based on the above other monomer may be the same or different in each occurrence, and the polymer (1) may contain polymerization units based on two or more different other monomers.

[0086] When the polymer (1) contains the polymerization unit (1) and a polymerization unit based on another monomer copolymerizable with the monomer (1), the content of the polymerization unit (1) based on the monomer (1) is preferably 40 to 60 mol%, more preferably 45 to 55 mol%, based on all the polymerization units constituting the polymer (1), and the content of the polymerization unit based on the other monomer is preferably 60 to 40 mol%, more preferably 55 to 45 mol%, based on all the polymerization units constituting the polymer (1). Such a configuration is particularly suitable when the polymerization unit based on another monomer copolymerizable with the monomer (1) is a polymerization unit based on a monomer represented by the general formula CFR=CR2.

[0087] When the polymer (1) contains the polymerization unit (1) and a polymerization unit based on another monomer copolymerizable with the monomer (1), the alternation ratio between the polymerization unit (1) and the polymerization unit based on another monomer copolymerizable with the monomer (1) is preferably 40% or more, more preferably 50% or more, still more preferably 60% or more, yet still more preferably 70% or more, particularly preferably 80% or more, and most preferably 90% or more. The alternation ratio may be, for example, 40 to 99%. Such a configuration is particularly suitable when the polymerization unit based on another monomer copolymerizable with the monomer (1) is a polymerization unit based on a monomer represented by the general formula CFR=CR2.

[0088] The alternating ratio between the polymerization unit (1) in the polymer (1) and the polymerization unit based on another monomer copolymerizable with the monomer (1) is that of the polymer (1) 19 It can be determined by 19F-NMR analysis.

[0089] For example, when the monomer (1) is CF2=CFOCF2CF2COOH and the other monomer is vinylidene fluoride (CH2=CF2), the alternating ratio of the polymer (1) can be calculated by the following method. The 19 19F-NMR measurement is performed, and from the total integral values of the two peaks (-79 ppm to -83 ppm and -83 ppm to -87 ppm) derived from "OCF2" of CF2=CFOCF2CF2COOH appearing in the NMR spectrum, it is calculated according to the following calculation formula. * Alternating ratio (%) ≧ (b × 2) / (a + b) × 100 Alternating ratio (%) ≧ (b × 2) / (a + b) × 100 a: Total integral value of the peak in the -79 ppm to -83 ppm area b: Total integral value of the peak in the -83 ppm to -87 ppm area

[0090] Examples of the other monomer also include the general formula (n1-2):

[0091]

Chemical formula

[0092] (In the formula, X 1 , X 2 are the same or different and are H or F; X 3 is H, F, Cl, CH3 or CF3; X 4 , X 5 are the same or different and are H or F; a and c are the same or different and are 0 or 1. Rf 3 is a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having an ether bond and having 2 to 100 carbon atoms).

[0093] Specifically, CH2=CFCF2-O-Rf 3 , CF2=CF-O-Rf 3 , CF2=CFCF2-O-Rf 3 , CF2=CF-Rf 3 , CH2=CH-Rf 3 , CH2=CH-O-Rf 3 (wherein, Rf 3 is the same as the above formula (n1-2)) and the like are preferably exemplified.

[0094] As the above other monomer, the formula (n2-1):

[0095]

Chemical formula

[0096] (wherein, X 9 is H, F or CH3; Rf 4 is a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having an ether bond and 2 to 100 carbon atoms) and the fluorine-containing acrylate monomer represented thereby is also exemplified. The above Rf 4 group is

[0097]

Chemical formula

[0098] (wherein, d3 is an integer of 1 to 4; e3 is an integer of 1 to 10) and the like are exemplified.

[0099] As the above other monomer, the formula (n2-2): CH2=CHO-Rf 5 (n2-2) (wherein, Rf 5 is a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having an ether bond and 2 to 100 carbon atoms) and the fluorine-containing vinyl ether represented thereby is also exemplified.

[0100] Specifically, as the monomer of the general formula (n2-2),

[0101] [Chemical formula]

[0102] (wherein, e6 is an integer from 1 to 10) and the like are preferably exemplified.

[0103] More specifically,

[0104] [Chemical formula]

[0105] and the like can be mentioned.

[0106] In addition, general formula (n2-3): CH2=CHCH2O-Rf 6 (n2-3) (wherein, Rf 6 is a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having an ether bond with 2 to 100 carbon atoms) represented by fluorine-containing allyl ether, general formula (n2-4): CH2=CH-Rf 7 (n2-4) (wherein, Rf 7 is a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having an ether bond with 2 to 100 carbon atoms) represented by fluorine-containing vinyl monomer and the like can also be mentioned.

[0107] Specifically, as the monomers represented by general formulas (n2-3) and (n2-4),

[0108] [Chemical formula]

[0109] and the like monomers can be mentioned.

[0110] In the polymer (1), the content of the polymerization unit (1) is, in order of increasing preference, 1.0 mol% or more, 3.0 mol% or more, 5.0 mol% or more, 10 mol% or more, 20 mol% or more, 30 mol% or more, 40 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, 90 mol% or more, based on all the polymerization units. It is particularly preferable that the content of the polymerization unit (1) is substantially 100 mol%, and it is most preferable that the polymer (1) consists only of the polymerization unit (1).

[0111] In the polymer (1), the content of the polymerization unit based on another monomer copolymerizable with the monomer represented by the general formula (1) is, in order of increasing preference, 99.0 mol% or less, 97.0 mol% or less, 95.0 mol% or less, 90 mol% or less, 80 mol% or less, 70 mol% or less, 60 mol% or less, 50 mol% or less, 40 mol% or less, 30 mol% or less, 20 mol% or less, 10 mol% or less, based on all the polymerization units. It is particularly preferable that the content of the polymerization unit based on another monomer copolymerizable with the monomer represented by the general formula (1) is substantially 0 mol%, and it is most preferable that the polymer (1) does not contain a polymerization unit based on another monomer.

[0112] The lower limit of the weight average molecular weight (Mw) of the polymer (1) is, in order of increasing preference, 0.2×10 4 or more, 0.4×10 4 or more, 0.6×10 4 or more, 0.8×10 4 or more, 1.0×10 4 or more, 1.3×10 4 or more, 1.4×10 4 or more, 1.5×10 4 or more, 1.7×10 4 or more, 1.9×10 4 or more, 2.1×10 4 or more, 2.3×10 4 or more, 2.7×10 4 or more, 3.1×10 4 or more, 3.5×10 4 or more, 3.9×10 4 or more, 4.3×10 4The above. As the upper limit of the weight-average molecular weight (Mw) of the polymer (1), in descending order of preference, is 150.0×10 4 or less, 100.0×10 4 or less, 60.0×10 4 or less, 50.0×10 4 or less, 40.0×10 4 or less.

[0113] As the lower limit of the number-average molecular weight (Mn) of the polymer (1), in descending order of preference, is 0.1×10 4 or more, 0.2×10 4 or more, 0.3×10 4 or more, 0.4×10 4 or more, 0.5×10 4 or more, 1.0×10 4 or more, 1.2×10 4 or more, 1.4×10 4 or more, 1.6×10 4 or more, 1.8×10 4 or more. As the upper limit of the number-average molecular weight (Mn) of the polymer (1), in descending order of preference, is 75.0×10 4 or less, 50.0×10 4 or less, 40.0×10 4 or less, 30.0×10 4 or less, 20.0×10 4 or less.

[0114] The molecular weight distribution (Mw / Mn) of the polymer (1) is preferably 2.4 or less, more preferably 2.2 or less, still more preferably 2.0 or less, and particularly preferably 1.9 or less.

[0115] The number average molecular weight and the weight average molecular weight are values calculated by gel permeation chromatography (GPC) using monodisperse polyethylene oxide (PEO) and polyethylene glycol (PEG) as standards for the molecular weight. Also, when measurement by GPC is not possible, the number average molecular weight of polymer (1) can be determined from the correlation between the number average molecular weight calculated from the number of end groups obtained by NMR, FT-IR, etc. and the melt flow rate. The melt flow rate can be measured in accordance with JIS K 7210.

[0116] Polymer (1) usually has end groups. The end groups are end groups generated during polymerization, and typical end groups are independently selected from hydrogen, iodine, bromine, linear or branched alkyl groups, and linear or branched fluoroalkyl groups, and may optionally additionally contain at least one chain heteroatom. The alkyl group or fluoroalkyl group preferably has 1 to 20 carbon atoms. These end groups are generally generated from the initiator or chain transfer agent used in the formation of polymer (1) or are generated during the chain transfer reaction.

[0117] Polymer (1) preferably has an ion exchange ratio (IXR) of 53 or less. The above IXR is defined as the number of carbon atoms in the polymer main chain relative to the ionic group. Precursor groups that become ionic upon hydrolysis (e.g., -COOCH3) are not regarded as ionic groups for the purpose of determining the IXR.

[0118] The IXR is preferably 0.5 or more, more preferably 0.7 or more, still more preferably 1.0 or more, even more preferably 1.2 or more, particularly preferably 1.5 or more, and most preferably 1.9 or more. Also, the IXR is more preferably 30 or less, still more preferably 10 or less, particularly preferably 3 or less, and most preferably 2.2 or less.

[0119] The ion exchange capacity of the polymer (1) is preferably, in descending order of preference, 0.80 meq / g or more, 1.50 meq / g or more, 1.75 meq / g or more, 2.00 meq / g or more, 2.40 meq / g or more, 2.50 meq / g or more, 2.60 meq / g or more, 3.00 meq / g or more, 3.50 meq / g or more. The ion exchange capacity is the content of the ionic groups (-COOM) of the polymer (1) and is determined by calculation from the composition of the polymer (1). A precursor group that becomes ionic by hydrolysis (for example, -COOCH3) is not regarded as an ionic group for the purpose of determining the ion exchange capacity. A higher ion exchange capacity of the polymer (1) means that there are more anionic groups in the polymer (1), and stable particles are formed. In addition, since the particle-forming ability is high, the number of particles per unit amount of water increases, and it is presumed that a higher polymerization rate is achieved. If the ion exchange capacity of the polymer (1) is too low, the fluorine-containing elastomer generated by polymerization may adhere to the polymerization tank, a sufficient polymerization rate may not be obtained, or the number of fluorine-containing elastomer particles generated may be small.

[0120] In the polymer (1), the ionic groups (-COOM) are typically distributed along the polymer main chain. The polymer (1) includes the polymer main chain together with repeating side chains bonded to this main chain, and it is preferable that these side chains have ionic groups.

[0121] The polymer (1) preferably contains ionic groups (-COOM) having a pKa of less than 10, more preferably less than 7.

[0122] The polymer (1) preferably has water solubility. Water solubility means the property of being easily dissolved or dispersed in an aqueous medium. A water-soluble polymer cannot, for example, have its particle size measured by the dynamic light scattering method (DLS). On the other hand, a water-insoluble polymer can have its particle size measured by, for example, the dynamic light scattering method (DLS).

[0123] As the polymer (1), a polymer (12) of a monomer (12) represented by the general formula (12), wherein the content of the polymerization unit (12) based on the monomer (12) is 50 mol% or more with respect to all the polymerization units constituting the polymer (12), and the weight average molecular weight (Mw) is 1.4×10 4 or more can also be used. The polymer (12) is a novel polymer. General formula (12): CF2=CF-O-Rf-COOM (In the formula, X is independently F or CF3, Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms, or a fluorine-containing alkylene group having an ether bond or a keto group and having 2 to 100 carbon atoms. M is H, a metal atom, NR 7 4, an imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent, and R 7 is H or an organic group.)

[0124] Regarding Rf and M in the general formula (12), they are the same as Rf and M in the general formula (2) representing the monomer constituting the polymer (2).

[0125] The polymer (12) may be a homopolymer consisting only of the polymerization unit (12) based on the monomer (12), or may be a copolymer containing the polymerization unit (12) and a polymerization unit based on another monomer copolymerizable with the monomer (12). The other monomers are as described above. The polymerization unit (12) may be the same or different at each occurrence, and the polymer (12) may contain polymerization units (12) based on two or more different monomers represented by the general formula (12).

[0126] As the content of the polymerization unit (12) in the polymer (12), in order of more preferable, it is 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, 90 mol% or more, 99 mol% or more with respect to all the polymerization units constituting the polymer (12). It is particularly preferable that the content of the polymerization unit (12) is substantially 100 mol%, and it is most preferable that the polymer (12) consists only of the polymerization unit (12).

[0127] In the polymer (12), the content of the polymerization unit based on another monomer copolymerizable with the monomer (12) is, in order of increasing preference, 50 mol% or less, 40 mol% or less, 30 mol% or less, 20 mol% or less, 10 mol% or less, 1 mol% or less, based on all the polymerization units constituting the polymer (12). The content of the polymerization unit based on another monomer copolymerizable with the monomer (12) is particularly preferably substantially 0 mol%, and most preferably the polymer (12) does not contain a polymerization unit based on another monomer.

[0128] The lower limit of the weight average molecular weight (Mw) of the polymer (12) is, in order of increasing preference, 1.4×10 4 or more, 1.7×10 4 or more, 1.9×10 4 or more, 2.1×10 4 or more, 2.3×10 4 or more, 2.7×10 4 or more, 3.1×10 4 or more, 3.5×10 4 or more, 3.9×10 4 or more, 4.3×10 4 or more, 4.7×10 4 or more, 5.1×10 4 or more. The upper limit of the weight average molecular weight (Mw) of the polymer (12) is, in order of increasing preference, 150.0×10 4 or less, 100.0×10 4 or less, 60.0×10 4 or less, 50.0×10 4 or less, 40.0×10 4 or less.

[0129] The lower limit of the number average molecular weight (Mn) of the polymer (12) is, in order of increasing preference, 1.0×10 4 or more, 1.2×10 4 or more, 1.4×10 4 or more, 1.6×10 4 or more, 1.8×10 4 or more. The upper limit of the number average molecular weight (Mn) of the polymer (12) is, in order of increasing preference, 75.0×104 Hereinafter, 50.0×10 4 Hereinafter, 40.0×10 4 Hereinafter, 30.0×10 4 Hereinafter, 20.0×10 4 It is as follows.

[0130] The molecular weight distribution (Mw / Mn) of the polymer (12) is preferably 3.0 or less, more preferably 2.4 or less, still more preferably 2.2 or less, particularly preferably 2.0 or less, and most preferably 1.9 or less.

[0131] Among the polymers (1), the polymer (12) is a novel polymer, and in an aqueous medium, by polymerizing the monomer (12) represented by the general formula (12), it is a method for producing the polymer (12) for producing the polymer (12) of the monomer (12), and it can be produced by a production method (12) that maintains the oxygen concentration in the reaction system of the polymerization at 1500 volume ppm or less.

[0132] In the production method (12), the oxygen concentration in the reaction system of the polymerization is 1500 volume ppm or less. In the production method (12), throughout the entire period of the polymerization of the monomer (12), the oxygen concentration in the reaction system is maintained at 1500 volume ppm or less. The oxygen concentration in the reaction system is preferably 500 volume ppm or less, more preferably 100 volume ppm or less, still more preferably 50 volume ppm or less. Also, the oxygen concentration in the reaction system is usually 0.01 volume ppm or more.

[0133] In the production method (12), the polymerization temperature of the monomer (12) is preferably 70°C or less, more preferably 65°C or less, still more preferably 60°C or less, particularly preferably 55°C or less, extremely preferably 50°C or less, especially preferably 45°C or less, most preferably 40°C or less, and preferably 10°C or more, more preferably 15°C or more, still more preferably 20°C or more, because a polymer (12) with a higher molecular weight can be easily produced.

[0134] In the production method (12), the monomer (12) may be copolymerized with the other monomers described above.

[0135] In the production method (12), the polymerization pressure is usually from atmospheric pressure to 10 MPaG. The polymerization pressure is appropriately determined according to the type of monomer used, the molecular weight of the target polymer, and the reaction rate.

[0136] In the production method (12), the polymerization time is usually from 1 to 200 hours, and may be from 5 to 100 hours.

[0137] In the production method (12), the oxygen concentration in the polymerization reaction system can be controlled, for example, by passing an inert gas such as nitrogen or argon, or the gaseous monomer when using a gaseous monomer, through the liquid phase or gas phase in the reactor. The oxygen concentration in the polymerization reaction system can be determined by measuring and analyzing the gas coming out from the exhaust gas line of the polymerization system with a low-concentration oxygen analyzer.

[0138] In the production method (12), the aqueous medium is a reaction medium for carrying out polymerization, and means a liquid containing water. The aqueous medium is not particularly limited as long as it contains water, and may contain water and, for example, a fluorine-free organic solvent such as alcohol, ether, or ketone, and / or a fluorine-containing organic solvent having a boiling point of 40°C or lower. Preferably, the aqueous medium is water.

[0139] In the production method (12), the polymerization of the monomer can be carried out in the presence of a polymerization initiator. The polymerization initiator is not particularly limited as long as it can generate radicals in the above polymerization temperature range, and known oil-soluble and / or water-soluble polymerization initiators can be used. Furthermore, polymerization can also be initiated as a redox in combination with a reducing agent or the like. The concentration of the polymerization initiator is appropriately determined according to the type of monomer, the molecular weight of the target polymer, and the reaction rate.

[0140] As the polymerization initiator, persulfates (e.g., ammonium persulfate), and organic peroxides such as disuccinic peroxide and diglutaric peroxide can be used alone or in the form of mixtures thereof. Further, it may be used in a redox system in combination with a reducing agent such as sodium sulfite. Furthermore, during the polymerization, a radical scavenger such as hydroquinone or catechol can be added, or a peroxide decomposer such as ammonium sulfite can be added to adjust the radical concentration in the system.

[0141] As the polymerization initiator, persulfates are particularly preferred because a polymer with a higher molecular weight can be easily produced. Examples of persulfates include ammonium persulfate, potassium persulfate, sodium persulfate, etc., and ammonium persulfate is preferred.

[0142] The addition amount of the polymerization initiator is not particularly limited, but it may be added all at once, sequentially, or continuously at the beginning of the polymerization in an amount such that the polymerization rate does not decrease significantly (for example, several ppm with respect to the water concentration) or more. The upper limit is in a range where the reaction temperature may be increased while removing the heat of polymerization reaction from the equipment surface, and a more preferable upper limit is in a range where the heat of polymerization reaction can be removed from the equipment surface.

[0143] In the production method (12), the polymerization initiator can be added at the start of polymerization and also during the polymerization. The ratio of the addition amount of the polymerization initiator added at the start of polymerization to the addition amount of the polymerization initiator added during the polymerization is preferably 95 / 5 to 5 / 95, more preferably 60 / 40 to 10 / 90, and even more preferably 30 / 70 to 15 / 85. The addition method of the polymerization initiator added during the polymerization is not particularly limited, and it may be added all at once, divided into two or more portions and added, or added continuously.

[0144] In the production method (12), since a polymer with an even higher molecular weight can be easily produced, the total addition amount of the polymerization initiator used in the polymerization is preferably 0.00001 to 10% by mass based on the aqueous medium. As the total addition amount of the polymerization initiator used in the polymerization, more preferably it is 0.0001% by mass or more, still more preferably 0.001% by mass or more, particularly preferably 0.01% by mass or more, more preferably 5% by mass or less, still more preferably 2% by mass or less.

[0145] In the production method (12), since a polymer with an even higher molecular weight can be easily produced, the total addition amount of the polymerization initiator used in the polymerization is preferably 0.001 to 10 mol% based on the monomer. As the total addition amount of the polymerization initiator used in the polymerization, more preferably it is 0.005 mol% or more, still more preferably 0.01 mol% or more, more preferably 5 mol% or less, still more preferably 2.5 mol% or less, particularly preferably 2.2 mol% or less, and most preferably 2.0 mol% or less.

[0146] In the production method (12), since a monomer with an even higher molecular weight can be easily produced, the abundance of the monomer containing monomer (12) at the start of polymerization is preferably 30% by mass or more based on the abundance of the aqueous medium. As the abundance of the monomer, more preferably it is 35% by mass or more, still more preferably 40% by mass or more. The upper limit of the abundance of the monomer is not particularly limited, but from the perspective of allowing the polymerization to proceed smoothly, it may be 200% by mass or less. The abundance of the monomer at the start of polymerization refers to the total abundance of monomer (12) and, if present, other monomers present in the reactor at the start of polymerization.

[0147] In the production method (12), the polymerization may be carried out in the presence of a pH adjuster. The pH adjuster may be added before the start of polymerization or after the start of polymerization.

[0148] As the pH adjuster, ammonia, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, ammonium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, ammonium hydrogen carbonate, sodium phosphate, potassium phosphate, sodium citrate, potassium citrate, ammonium citrate, sodium gluconate, potassium gluconate, ammonium gluconate, etc. can be used.

[0149] In the production method (12), the polymerization of the monomer (12) can be carried out by charging an aqueous medium, the monomer (12), and, if necessary, other monomers and, if necessary, other additives into a reactor, stirring the contents of the reactor, maintaining the reactor at a predetermined polymerization temperature, then adding a predetermined amount of a polymerization initiator, and starting the polymerization reaction. After the start of the polymerization reaction, monomers, polymerization initiators, and other additives may be added according to the purpose.

[0150] In the production method (12), the polymerization of the monomer can be carried out in the substantial absence of a fluorine-containing surfactant. In the present disclosure, "in the substantial absence of a fluorine-containing surfactant" means that the amount of the fluorine-containing surfactant relative to the aqueous medium is 10 mass ppm or less. The amount of the fluorine-containing surfactant relative to the aqueous medium is preferably 1 mass ppm or less, more preferably 100 mass ppb or less, still more preferably 10 mass ppb or less, and even more preferably 1 mass ppb or less.

[0151] In the production method of the present disclosure, the addition amount of the polymer (1) is preferably 0.0001 to 2% by mass with respect to 100% by mass of the aqueous medium. By setting the addition amount (existence amount) of the polymer (1) in the above polymerization within the above range, the polymerization reaction of the fluorine-containing monomer proceeds smoothly, and the fluorine-containing elastomer can be efficiently produced. If the addition amount of the polymer (1) is too small, a sufficient polymerization rate or a sufficient yield may not be obtained.

[0152] As the addition amount of the polymer (1), since the polymerization reaction of the fluorine-containing monomer proceeds more smoothly, it is more preferably 0.0005% by mass or more, still more preferably 0.001% by mass or more, particularly preferably 0.005% by mass or more, and most preferably 0.01% by mass or more, based on 100% by mass of the aqueous medium.

[0153] Also, as the addition amount of the polymer (1), if the addition amount is too large, an effect commensurate with the addition amount cannot be obtained and it is economically disadvantageous. Therefore, it is more preferably 2% by mass or less, still more preferably 1% by mass or less, particularly preferably 0.5% by mass or less, based on 100% by mass of the aqueous medium.

[0154] The timing of adding the polymer (1) in the above polymerization is not particularly limited, and it may be added before the start of polymerization or after the start of polymerization. Also, in the above polymerization, the polymer (1) may be added all at once at an arbitrary timing or continuously. Continuously adding the polymer (1) means, for example, adding the polymer (1) not all at once, but over time and without interruption or in portions. When continuously adding the polymer (1), it is preferable to add it so that the total amount of the added polymer (1) falls within the above-described range of the addition amount. When adding the polymer (1), an aqueous solution containing the polymer (1) and water may be prepared and the aqueous solution may be added.

[0155] As the polymer (1), an aqueous solution containing the polymer (1) can be used.

[0156] The polymer (1) or the aqueous solution containing the polymer (1) may contain the dimer and trimer of the monomer (1), or may substantially not contain the dimer and trimer of the monomer (1). The dimer and trimer of the monomer (1) are usually formed when the monomer (1) is polymerized to obtain the polymer (1). The content of the dimer and trimer in the polymer (1) or in the aqueous solution containing the polymer (1) is 1.0% by mass or less, preferably 0.1% by mass or less, more preferably 0.01% by mass or less, still more preferably 0.001% by mass or less, and particularly preferably 0.0001% by mass or less based on the polymer (1).

[0157] The content of the dimer and trimer in the polymer (1) or in the aqueous solution containing the polymer (1) can be specified by performing gel permeation chromatography (GPC) analysis on the polymer (1) and calculating the ratio (area percentage) of the total peak area of the dimer and trimer to the total peak area of each peak in the chromatogram obtained by the GPC analysis.

[0158] When the content of the dimer and trimer in the polymer (1) or in the aqueous solution containing the polymer (1) is less than 0.5% by mass based on the polymer (1), it can be specified by measurement using liquid chromatography-mass spectrometry (LC / MS). Specifically, aqueous solutions with five or more levels of the content of the monomer (1) are prepared, LC / MS analysis is performed on each content, the relationship between the content and the area area (integral value of the peak) corresponding to the content is plotted, and a calibration curve of the monomer (1) is created. Further, a calibration curve of the dimer and trimer of the monomer (1) is created from the calibration curve of the monomer (1). Methanol is added to the polymer (1) to prepare a mixture, which is filtered using an ultrafiltration disk (molecular weight cut-off 3000 Da), and the obtained recovered solution is subjected to LC / MS analysis. Then, using the calibration curve, the area area (integral value of the peak) of the chromatogram of the dimer and trimer of the monomer (1) can be converted into the content of the dimer and trimer.

[0159] The dimers and trimers in the polymer (1) or in the aqueous solution containing the polymer (1) can be removed by treating the aqueous solution containing the polymer (1) by at least one means selected from the group consisting of ultrafiltration, microfiltration, dialysis membrane treatment, liquid separation, and reprecipitation.

[0160] The production method of the present disclosure can efficiently produce a fluorine-containing elastomer if at least one kind of the polymer (1) is used. Further, in the production method of the present disclosure, two or more kinds of the polymer (1) may be used simultaneously, and other compounds having surface activity may be used simultaneously as long as they are volatile or may remain in a molded article containing a fluorine-containing elastomer.

[0161] The production method of the present disclosure preferably polymerizes a fluorine-containing monomer substantially in the absence of a fluorine-containing surfactant.

[0162] Conventionally, a fluorine-containing surfactant has been used for the polymerization of a fluorine-containing monomer. However, in the production method of the present disclosure, by using the polymer (1), a fluorine-containing monomer can be polymerized without using a fluorine-containing surfactant to obtain a fluorine-containing elastomer.

[0163] In the present disclosure, "substantially in the absence of a fluorine-containing surfactant" means that the content ratio of the fluorine-containing surfactant with respect to the aqueous medium is 10 mass ppm or less. The content ratio of the fluorine-containing surfactant is preferably 1 mass ppm or less, more preferably 100 mass ppb or less, still more preferably 10 mass ppb or less, and particularly preferably 1 mass ppb or less.

[0164] Examples of the above-mentioned fluorine-containing surfactant include anionic fluorine-containing surfactants. As the above-mentioned fluorine-containing surfactant, a fluorine-containing surfactant (excluding a compound having a functional group capable of reacting in radical polymerization and a hydrophilic group) is preferred.

[0165] The above anionic fluorine-containing surfactant may be, for example, a surfactant containing fluorine atoms with a total carbon number of 20 or less in the portion excluding the anionic group.

[0166] The above fluorine-containing surfactant may also be a surfactant containing fluorine with a molecular weight of the anionic portion of 800 or less.

[0167] Note that the above "anionic portion" means the portion excluding the cation of the above fluorine-containing surfactant. For example, in the case of F(CF2) n1 COOM represented by the formula (I) described later, it is the portion of "F(CF2) n1 COO".

[0168] Examples of the above fluorine-containing surfactant also include fluorine-containing surfactants with a LogPOW of 3.5 or less. The above LogPOW is the partition coefficient between 1-octanol and water, and is represented by LogP [where P represents the ratio of the concentration of the fluorine-containing surfactant in octanol to the concentration of the fluorine-containing surfactant in water when an octanol / water (1:1) mixed solution containing the fluorine-containing surfactant is phase-separated].

[0169] The above LogPOW is determined by performing HPLC on standard substances (heptanoic acid, octanoic acid, nonanoic acid, and decanoic acid) having a known octanol / water partition coefficient under the conditions of column; TOSOH ODS-120T column (φ4.6 mm × 250 mm, manufactured by Tosoh Corporation), eluent; acetonitrile / 0.6 mass% HClO4 water = 1 / 1 (vol / vol%), flow rate; 1.0 ml / min, sample volume; 300 μL, column temperature; 40 °C, detection light; UV210 nm, creating a calibration curve between each elution time and the known octanol / water partition coefficient, and calculating from the elution time of HPLC in the sample solution based on this calibration curve.

[0170] Specific examples of the fluorosurfactant include those described in 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 / 0142541, U.S. Patent Application Publication No. 2008 / 0015319, U.S. Patent No. 3250808, U.S. Patent No. 3271341, Japanese Patent Application Laid-Open No. 2003-119204, International Publication No. 2005 / 042593, International Publication No. 2008 / 060461, International Publication No. 2007 / 046377, Japanese Patent Application Laid-Open 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, International Publication No. 2013 / 189826, etc.

[0171] Examples of the anionic fluorosurfactant include the following general formula (N 0 ): X n0 -Rf n0 -Y 0 (N 0 ) (In the formula, X n0 is H, Cl, or F. Rf n0 is an alkylene group having 3 to 20 carbon atoms, which is linear, branched, or cyclic, and in which some or all of the H atoms are substituted by F atoms. The alkylene group may contain one or more ether bonds, and some of the H atoms may be substituted by Cl atoms. Y 0 is an anionic group.) Compounds represented by the formula are included.

[0172] Y 0 The anionic group of may be -COOM, -SO2M, or -SO3M, and may be -COOM or -SO3M.

[0173] M is H, a metal atom, NR 74. Optionally substituted imidazolium, optionally substituted pyridinium or optionally substituted phosphonium, where R 7 is -H or an organic group.

[0174] Examples of the above metal atoms include alkali metals (Group 1), alkaline earth metals (Group 2), etc., for example, Na, K or Li.

[0175] R 7 may be -H or an organic group of C 1-10 and may be -H or an organic group of C 1-4 and may be -H or an alkyl group of C 1-4 .

[0176] M may be H, a metal atom or NR 7 4, and may be H, an alkali metal (Group 1), an alkaline earth metal (Group 2) or NR 7 4, and may be H, Na, K, Li or NH4.

[0177] The above Rf n0 may be one in which 50% or more of H is substituted with fluorine.

[0178] Examples of the compound represented by the above general formula (N 0 ) include the following general formula (N 1 ): X n0 -(CF2) m1 -Y 0 (N 1 ) (wherein X n0 is H, Cl and F, m1 is an integer of 3 to 15, and Y 0 is as defined above.). A compound represented by the following general formula (N 2 ): Rf n1 -O-(CF(CF3)CF2O) m2 CFX n1 -Y 0 (N 2 ) (wherein, Rf n1 is a perfluoroalkyl group having 1 to 5 carbon atoms, m2 is an integer of 0 to 3, X n1 is F or CF3, Y 0 is as defined above.) A compound represented by the following general formula (N 3 ): Rf n2 (CH2) m3 -(Rf n3 ) q -Y 0 (N 3 ) (wherein, Rf n2 is a partially or completely fluorinated alkyl group which may contain an ether bond having 1 to 13 carbon atoms and / or a chlorine atom, m3 is an integer of 1 to 3, Rf n3 is a linear or branched perfluoroalkylene group having 1 to 3 carbon atoms, q is 0 or 1, Y 0 is as defined above.) A compound represented by the following general formula (N 4 ): Rf n4 -O-(CY n1 Y n2 ) p CF2-Y 0 (N 4 ) (wherein, Rf n4 is a linear or branched partially or completely fluorinated alkyl group which may contain an ether bond having 1 to 12 carbon atoms, Y n1 and Y n2 are the same or different and are H or F, p is 0 or 1, Y 0 is as defined above.) A compound represented by the following general formula (N 5 ): [Chemical formula] (wherein, X n2 , X n3 and X n4 may be the same or different and are H, F, or a linear or branched partially or completely fluorinated alkyl group which may contain an ether bond having 1 to 6 carbon atoms. Rfn5 is a linear or branched or fully fluorinated alkylene group which may contain an ether bond having 1 to 3 carbon atoms, L is a linking group, and Y 0 is as defined above. However, X n2 , X n3 , X n4 and Rf n5 The total number of carbon atoms of is 18 or less. Compounds represented by the formula () can be mentioned.

[0179] More specifically, as the compound represented by the above general formula (N 0 ), a perfluorocarboxylic acid (I) represented by the following general formula (I), an ω-H perfluorocarboxylic acid (II) represented by the following general formula (II), a perfluoroether carboxylic acid (III) represented by the following general formula (III), a perfluoroalkylalkylene carboxylic acid (IV) represented by the following general formula (IV), a perfluoroalkoxyfluorocarboxylic acid (V) represented by the following general formula (V), a perfluoroalkylsulfonic acid (VI) represented by the following general formula (VI), an ω-H perfluorosulfonic acid (VII) represented by the following general formula (VII), a perfluoroalkylalkylene sulfonic acid (VIII) represented by the following general formula (VIII), an alkylalkylene carboxylic acid (IX) represented by the following general formula (IX), a fluorocarboxylic acid (X) represented by the following general formula (X), an alkoxyfluorosulfonic acid (XI) represented by the following general formula (XI), a compound (XII) represented by the following general formula (XII), a compound (XIII) represented by the following general formula (XIII), etc. can be mentioned.

[0180] The above perfluorocarboxylic acid (I) is represented by the following general formula (I) F(CF2) n1 COOM (I) (In the formula, n1 is an integer of 3 to 14, M is H, a metal atom, NR 7 4, an imidazolium which may have a substituent, a pyridinium which may have a substituent or a phosphonium which may have a substituent, and R 7 is -H or an organic group.)

[0181] The above ω-H perfluorocarboxylic acid (II) is represented by the following general formula (II) H(CF2) n2 COOM (II) (wherein n2 is an integer from 4 to 15, and M is as defined above.)

[0182] The above perfluoroether carboxylic acid (III) is represented by the following general formula (III) Rf 1 -O-(CF(CF3)CF2O) n3 CF(CF3)COOM (III) (wherein Rf 1 is a perfluoroalkyl group having 1 to 5 carbon atoms, n3 is an integer from 0 to 3, and M is as defined above.)

[0183] The above perfluoroalkylalkylene carboxylic acid (IV) is represented by the following general formula (IV) Rf 2 (CH2) n4 Rf 3 COOM (IV) (wherein Rf 2 is a perfluoroalkyl group having 1 to 5 carbon atoms, Rf 3 is a linear or branched perfluoroalkylene group having 1 to 3 carbon atoms, n4 is an integer from 1 to 3, and M is as defined above.)

[0184] The above alkoxyfluorocarboxylic acid (V) is represented by the following general formula (V) Rf 4 -O-CY 1 Y 2 CF2-COOM (V) (wherein Rf 4 is a linear or branched partial or fully fluorinated alkyl group which may contain an ether bond and / or a chlorine atom having 1 to 12 carbon atoms, Y 1 and Y 2is the same or different and is H or F, and M is as defined above.) is represented by

[0185] The above perfluoroalkylsulfonic acid (VI) is represented by the following general formula (VI) F(CF2) n5 SO3M (VI) (wherein n5 is an integer from 3 to 14, and M is as defined above.) is represented by

[0186] The above ω-H perfluorosulfonic acid (VII) is represented by the following general formula (VII) H(CF2) n6 SO3M (VII) (wherein n6 is an integer from 4 to 14, and M is as defined above.) is represented by

[0187] The above perfluoroalkylalkylene sulfonic acid (VIII) is represented by the following general formula (VIII) Rf 5 (CH2) n7 SO3M (VIII) (wherein Rf 5 is a perfluoroalkyl group having 1 to 13 carbon atoms, n7 is an integer from 1 to 3, and M is as defined above.) is represented by

[0188] The above alkylalkylene carboxylic acid (IX) is represented by the following general formula (IX) Rf 6 (CH2) n8 COOM (IX) (wherein Rf 6 is a linear or branched or fully fluorinated alkyl group which may contain an ether bond having 1 to 13 carbon atoms, n8 is an integer from 1 to 3, and M is as defined above.) is represented by

[0189] The above fluorocarboxylic acid (X) is represented by the following general formula (X) Rf 7 -O-Rf 8-O-CF2-COOM (X) (wherein, Rf 7 is a linear or branched or fully fluorinated alkyl group which may contain an ether bond having 1 to 6 carbon atoms and / or a chlorine atom, Rf 8 is a linear or branched or fully fluorinated alkyl group having 1 to 6 carbon atoms, and M is as defined above.) is represented by the following formula.

[0190] The above alkoxyfluorosulfonic acid (XI) is represented by the following general formula (XI) Rf 9 -O-CY 1 Y 2 CF2-SO3M (XI) (wherein, Rf 9 is a linear or branched group which may contain an ether bond having 1 to 12 carbon atoms, and which may contain chlorine, a partially or fully fluorinated alkyl group, Y 1 and Y 2 are the same or different and are H or F, and M is as defined above.) is represented by the following formula.

[0191] The above compound (XII) is represented by the following general formula (XII):

Chemical formula

[0192] Y 0 may be -COOM, -SO2M, or -SO3M, and may be -SO3M or -COOM (wherein, M is as defined above).

[0193] Examples of L include a single bond, a moiety that may contain an ether bond having 1 to 10 carbon atoms, or a fully fluorinated alkylene group.

[0194] The above compound (XIII) has the following general formula (XIII): Rf 11 -O-(CF2CF(CF3)O) n9 (CF2O) n10 CF2COOM (XIII) (wherein Rf 11 is a fluoroalkyl group having 1 to 5 carbon atoms containing chlorine, n9 is an integer of 0 to 3, n10 is an integer of 0 to 3, and M is as defined above.) It is represented by. As the compound (XIII), CF2ClO(CF2CF(CF3)O) n9 (CF2O) n10 CF2COONH4 (a mixture with an average molecular weight of 750, wherein n9 and n10 are as defined above.) may be mentioned.

[0195] The fluorine-containing surfactant may be a single fluorine-containing surfactant or a mixture containing two or more fluorine-containing surfactants.

[0196] Examples of the fluorine-containing surfactant include compounds represented by the following formulas. The fluorine-containing surfactant may be a mixture of these compounds. In one embodiment of the above polymerization, the fluoromonomer is polymerized substantially in the absence of a compound represented by the following formula. F(CF2)7COOM, F(CF2)5COOM, H(CF2)6COOM, H(CF2)7COOM, CF3O(CF2)3OCHFCF2COOM, C3F7OCF(CF3)CF2OCF(CF3)COOM, CF3CF2CF2OCF(CF3)COOM, CF3CF2OCF2CF2OCF2COOM, C2F5OCF(CF3)CF2OCF(CF3)COOM, CF3OCF(CF3)CF2OCF(CF3)COOM, CF2ClCF2CF2OCF(CF3)CF2OCF2COOM, CF2ClCF2CF2OCF2CF(CF3)OCF2COOM, CF2ClCF(CF3)OCF(CF3)CF2OCF2COOM, CF2ClCF(CF3)OCF2CF(CF3)OCF2COOM,

Chem.

[0197] In the production method of the present disclosure, the polymerization of the fluorine-containing monomer can be carried out, for example, by charging a polymer (1) and an aqueous medium into a pressure-resistant polymerization tank equipped with a stirrer, deoxygenating, charging the monomer, bringing it to a predetermined temperature, adding a polymerization initiator, and starting the reaction. Since the pressure decreases as the reaction proceeds, additional monomer is continuously or intermittently added to maintain the initial pressure. When a predetermined amount of monomer has been supplied, the supply is stopped, the monomer in the reaction vessel is purged, and the temperature is returned to room temperature to terminate the reaction.

[0198] In the production method of the present disclosure, the polymerization may be carried out in the presence of a polymerization initiator.

[0199] Examples of the polymerization initiator include radical polymerization initiators. The polymerization initiator is not particularly limited as long as it can generate radicals at the temperature at which the fluorine-containing monomer is polymerized, and an oil-soluble polymerization initiator, a water-soluble polymerization initiator, an azo compound, etc. can be used, but a water-soluble polymerization initiator is preferred. Further, the polymerization initiator may be used as a redox initiator in combination with a reducing agent or the like.

[0200] When polymerizing the fluorine-containing monomer, the amount of the polymerization initiator is appropriately determined according to the type of the monomer, the molecular weight of the target fluorine-containing elastomer, and the reaction rate. The amount of the polymerization initiator is appropriately determined according to the molecular weight of the target fluorine-containing elastomer and the polymerization reaction rate, but is preferably 0.00001 to 10% by mass, more preferably 0.0001 to 1% by mass, based on 100% by mass of the total amount of the monomers.

[0201] As the polymerization initiator, an oil-soluble radical polymerization initiator or a water-soluble radical polymerization initiator can be used.

[0202] As the oil-soluble radical polymerization initiator, it may be a known oil-soluble peroxide. For example, dialkyl peroxydicarbonates such as diisopropyl peroxydicarbonate and di-sec-butyl peroxydicarbonate, peroxy esters such as t-butyl peroxyisobutyrate and t-butyl peroxypivalate, dialkyl peroxides such as di-t-butyl peroxide, etc. Also, di(ω-hydroxy-dodecafluorocaproyl) peroxide, di(ω-hydroxy-tetradecafluoroheptanoyl) peroxide, di(ω-hydroxy-hexadecafluorononanoyl) peroxide, di(perfluorobutyryl) peroxide, di(perfluorovaleryl) peroxide, di(perfluorohexanoyl) peroxide, di(perfluoroheptanoyl) peroxide, di(perfluorooctanoyl) peroxide, di(perfluorononanoyl) peroxide, di(ω-chloro-hexafluorobutyryl) peroxide, di(ω-chloro-decafluorohexanoyl) peroxide, di(ω-chloro-tetradecafluorooctanoyl) peroxide, ω-hydroxy-dodecafluoroheptanoyl-ω-hydroxy-hexadecafluorononanoyl-peroxide, ω-chloro-hexafluorobutyryl-ω-chloro-decafluorohexanoyl-peroxide, ω-hydroxy-dodecafluoroheptanoyl-perfluorobutyryl-peroxide, di(dichloropentafluorobutanoyl) peroxide, di(trichlorooctafluorohexanoyl) peroxide, di(tetrachloroundecafluorooctanoyl) peroxide, di(pentachlorotetradecafluorodecanoyl) peroxide, di(undecachlorodotriacontapentafluorodocosanoyl) peroxide and other di[perfluoro(or fluorochloro)acyl] peroxides are mentioned as typical ones.

[0203] Examples of the azo compound include azodicarboxylate, azodicarboxyldiamide, 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylpropionamidine) dihydrochloride, and 4,4'-azobis(4-cyanovaleric acid).

[0204] The water-soluble radical polymerization initiator may be a known water-soluble peroxide. For example, ammonium salts, potassium salts, sodium salts of persulfuric acid, perboric acid, perchloric acid, phosphoric acid, carbonic acid, etc., organic peroxides such as disuccinic peroxide, diglutaric peroxide, t-butyl permaleate, t-butyl hydroperoxide, etc. are included. Reducing agents such as sulfites may also be included, and the amount used may be 0.1 to 20 times that of the peroxide.

[0205] As the water-soluble peroxide, since it is easy to adjust the amount of generated radicals, salts of persulfuric acid are preferred, potassium persulfate (K2S2O8), ammonium persulfate ((NH4)2S2O8), sodium persulfate (Na2S2O8) are preferred, and ammonium persulfate is most preferred.

[0206] When the polymerization temperature is 45 °C or higher and the polymerization is carried out using a water-soluble peroxide, it is preferable to carry out the polymerization without using a reducing agent.

[0207] For example, when the polymerization is carried out at a low temperature of 60 °C or lower, etc., it is preferable to use a redox initiator that combines an oxidizing agent and a reducing agent as the polymerization initiator. That is, the above polymerization is preferably carried out in the presence of a redox initiator.

[0208] Examples of the oxidizing agent include persulfates, organic peroxides, potassium permanganate, manganese triacetate, ammonium cerium nitrate, bromates, and the like. Examples of the reducing agent include sulfites, bisulfites, bromates, diimines, oxalic acid, metal sulfinates, and the like. Examples of the persulfate include ammonium persulfate, potassium persulfate, and sodium persulfate. Examples of the sulfite include sodium sulfite and ammonium sulfite. In order to increase the decomposition rate of the initiator, it is also preferable to add a copper salt or an iron salt to the combination of the redox initiator. Examples of the copper salt include copper(II) sulfate, and examples of the iron salt include iron(II) sulfate. Further, when using a copper salt or an iron salt, it is particularly preferable to add a chelating agent. As the chelating agent, disodium ethylenediaminetetraacetate dihydrate is preferable.

[0209] Examples of the redox initiator include, for example, potassium permanganate / oxalic acid, ammonium persulfate / bisulfite / iron(II) sulfate, ammonium persulfate / sulfite / iron(II) sulfate, ammonium persulfate / sulfite, ammonium persulfate / iron(II) sulfate, manganese triacetate / oxalic acid, ammonium cerium nitrate / oxalic acid, bromate / sulfite, bromate / bisulfite, ammonium persulfate / sodium hydroxymethanesulfinate dihydrate, and the like, and ammonium persulfate / sodium hydroxymethanesulfinate dihydrate is preferable.

[0210] When using a redox initiator, either the oxidizing agent or the reducing agent may be charged into the polymerization tank in advance, and then the other may be added continuously or intermittently to initiate the polymerization. For example, when using ammonium persulfate / sodium hydroxymethanesulfinate dihydrate, it is preferable to charge ammonium persulfate into the polymerization tank and continuously add sodium hydroxymethanesulfinate dihydrate thereto.

[0211] The amount of the persulfate used 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 with respect to the above aqueous medium used for the polymerization.

[0212] The amount of the reducing agent used is preferably 1 to 30% by mass, more preferably 3 to 25% by mass, and particularly preferably 5 to 20% by mass, based on the aqueous medium used in the polymerization.

[0213] Also, the amount of the third component (such as the above-mentioned copper salt, iron salt, etc.) used 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, based on the aqueous medium used in the polymerization.

[0214] In the production method of the present disclosure, the fluorine-containing monomer may be further polymerized in the presence of a chain transfer agent. As the chain transfer agent, known ones can be used. For example, hydrocarbons, esters, ethers, alcohols, ketones, halogen-containing compounds, carbonates, etc. can be used. Among them, isopentane, diethyl malonate, and ethyl acetate are preferable from the viewpoint that the reaction rate is less likely to decrease, and diiodine compounds such as I(CF2)4I, I(CF2)6I, and ICH2I are preferable from the viewpoint that the iodineation of the polymer terminal is possible and it can be used as a reactive polymer.

[0215] As the chain transfer agent, it is particularly preferable to use a bromine compound or an iodine compound. Examples of the polymerization method using a bromine compound or an iodine compound include iodine transfer polymerization or bromine transfer polymerization.

[0216] Iodine compounds and bromine compounds are water-insoluble and difficult to emulsify. Therefore, there has been a tendency to use a large amount of surfactant in emulsion polymerization originally because there are limitations. According to the production method of the present disclosure, it has become possible to obtain a fluorine-containing elastomer by polymerization using an iodine compound or a bromine compound, for example, iodine transfer polymerization or bromine transfer polymerization, even in the absence of the surfactant conventionally used.

[0217] Iodine transfer polymerization is a method that utilizes living radical polymerization based on a radical chain reactivation mechanism, which occurs due to the involvement of a chain transfer reaction during a radical polymerization reaction because the dissociation energy of a carbon-iodine bond is low and thus it is radically active. Regarding the reaction conditions, known conditions can be appropriately used and are not particularly limited. For example, the conditions described in "Polymer Journal, Vol. 49, No. 10, pp. 765-783, October 1992" and Japanese Patent Laid-Open No. 53-3495 can be appropriately adopted. Similar polymerization can be carried out using a bromine compound instead of an iodine compound, and in the present disclosure, such polymerization is referred to as bromine transfer polymerization.

[0218] Among these, iodine transfer polymerization is preferred from the viewpoints of polymerization reactivity, crosslinking reactivity, etc.

[0219] Typical examples of the bromine compound or iodine compound include, for example, the general formula: R 8 I x Br y (wherein x and y are each an integer from 0 to 2 and satisfy 1 ≦ x + y ≦ 2, and R 8 is a saturated or unsaturated fluorohydrocarbon group or chlorofluorohydrocarbon group having 1 to 16 carbon atoms, or a hydrocarbon group having 1 to 3 carbon atoms, and may contain an oxygen atom) can be mentioned. By using a bromine compound or iodine compound, iodine or bromine is introduced into the polymer and functions as a crosslinking point.

[0220] Examples of bromine compounds and iodine compounds include 1,3-diiodoperfluoropropane, 2-iodoperfluoropropane, 1,3-diiodo-2-chloroperfluoropropane, 1,4-diiodoperfluorobutane, 1,5-diiodo-2,4-dichloroperfluoropentane, 1,6-diiodoperfluorhexane, 1,8-diiodoperfluorooctane, 1,12-diiodoperfluorododecane, 1,16-diiodoperfluorohexadecane, diiodomethane, 1,2-diiodoethane, 1,3-diiodo-n-propane, CF2Br2, BrCF2CF2Br, CF3CFBrCF2Br, CFClBr2, BrCF2CFClBr, CFBrClCFClBr, BrCF2CF2CF2Br, BrCF2CFBrOCF3, 1-bromo-2-iodoperfluoroethane, 1-bromo-3-iodoperfluoropropane, 1-bromo-4-iodoperfluorobutane, 2-bromo-3-iodoperfluorobutane, 3-bromo-4-iodoperfluorobuten-1, 2-bromo-4-iodoperfluorobuten-1, monobromoiodo-substituted products of benzene, dibromoiodo-substituted products, and (2-iodoethyl) and (2-bromoethyl) substituted products. These compounds may be used alone or in combination with each other. Among these, from the viewpoints of polymerization reactivity, crosslinking reactivity, availability, etc., compounds containing only iodine and no bromine are preferred, and it is preferable to use 1,4-diiodoperfluorobutane, 1,6-diiodoperfluorohexane, or 2-iodoperfluoropropane.

[0221] The amount of the chain transfer agent is preferably 0.2×10 -3 ~2 mol%, more preferably 1.0×10 -3 ~1 mol% based on the total amount of the monomers used in the polymerization.

[0222] The aqueous medium means a liquid containing water. The aqueous medium is not particularly limited as long as it contains water, and may contain water and, for example, a fluorine-free organic solvent such as alcohol, ether, ketone, etc., and / or a fluorine-containing organic solvent having a boiling point of 40°C or lower.

[0223] In the polymerization of the fluorine-containing monomer, phosphates, sodium hydroxide, potassium hydroxide, ammonia, etc. may be used as the pH adjuster.

[0224] The aqueous medium is preferably acidic. By using an acidic aqueous medium and polymerizing the fluorine-containing monomer in the presence of the polymer (1), a larger number of fluorine-containing polymer particles can be generated at a higher polymerization rate while further suppressing the adhesion of the fluorine-containing polymer to the polymerization tank. The pH of the aqueous medium is preferably 7 or less, more preferably 6 or less, and preferably 3 or more.

[0225] In the production method of the present disclosure, the fluorine-containing monomer may be polymerized in the presence or absence of the fluorine-containing monomer polymerization seed particles.

[0226] The above-mentioned "fluorine-containing monomer polymerization seed particles" are obtained by polymerizing the fluorine-containing monomer in an aqueous medium, and are present during the second polymerization when the types and proportions of components such as monomers and additives (for example, polymerization initiators, etc.) constituting the polymerization reaction system and the reaction conditions are different. The fluorine-containing monomer polymerization seed particles act as so-called seed particles during the polymerization of the fluorine-containing monomer, and constitute the polymerization of the fluorine-containing monomer in the presence of the seed particles, so-called seed polymerization. In the production method of the present disclosure, such seed polymerization may not be performed when polymerizing the fluorine-containing monomer.

[0227] In the production method of the present disclosure, the polymerization temperature for polymerizing the fluorine-containing monomer is preferably 10 to 120°C, more preferably 20 to 100°C. Further, from the viewpoints of the stability of the aqueous dispersion and the reduction of the adhesion rate, the polymerization temperature is preferably 15 to 60°C, more preferably 18 to 55°C, and even more preferably 20 to 50°C. Further, as the polymerization temperature, since a high polymerization rate can be achieved and a fluorine-containing elastomer that gives a molded article having excellent physical properties can be obtained, 60 to 120°C is preferable, 60 to 100°C is more preferable, and 70 to 90°C is even more preferable.

[0228] In the production method of the present disclosure, the polymerization pressure for polymerizing the fluorine-containing monomer is preferably 0.5 to 10 MPaG, more preferably 1 to 7 MPaG.

[0229] Since the production method of the present disclosure polymerizes the fluorine-containing monomer in the presence of the polymer (1) and the aqueous medium, it is possible to suppress the adhesion of the polymer (fluorine-containing elastomer) to the polymerization tank. The polymer adhesion rate to the polymerization tank is preferably 8% by mass or less, more preferably 4% by mass or less, even more preferably 3% by mass or less, and most preferably 2% by mass or less.

[0230] The polymer adhesion rate is the ratio (adhesion rate to the polymerization tank) of the mass of the polymer deposit adhered to the polymerization tank after the polymerization is completed to the total amount of the polymer (fluorine-containing elastomer) after the polymerization is completed. The polymer deposit includes the polymer adhered to the inside of the polymerization tank such as the inner wall of the polymerization tank and the stirring blade after the aqueous dispersion is withdrawn from the polymerization tank after the polymerization is completed, and the polymer that is released from the aqueous dispersion by aggregation and floats or precipitates without being dispersed in the aqueous dispersion. The mass of the polymer deposit is the mass after removing the moisture contained in the polymer deposit by drying at 120°C. Polymer adhesion rate (% by mass) = Mass of polymer deposit / Mass of obtained polymer (including deposit) × 100 Mass of obtained polymer = Mass of aqueous dispersion × Solid content concentration of aqueous dispersion (% by mass) / 100 + Mass of polymer deposit

[0231] In the production method of the present disclosure, an aqueous dispersion of a fluorine-containing elastomer is obtained by polymerizing a fluorine-containing monomer. The fluorine-containing monomer preferably does not contain a hydrophilic group.

[0232] Examples of the fluorine-containing monomer include vinylidene fluoride (VdF), tetrafluoroethylene (TFE), hexafluoropropylene (HFP), perfluoro(alkyl vinyl ether) (PAVE), chlorotrifluoroethylene (CTFE), trifluoroethylene, trifluoropropylene, tetrafluoropropylene, pentafluoropropylene, trifluorobutene, tetrafluoroisobutene, hexafluoroisobutene, vinyl fluoride, iodine-containing fluorinated vinyl ether, and a fluorine-containing monomer (2) represented by the general formula (2): CHX 1 =CX 2 Rf (2) (wherein X 1 and X 2 are such that one is H and the other is F, and Rf is a linear or branched fluoroalkyl group having 1 to 12 carbon atoms), and fluorine-containing monomers such as the fluorine-containing monomer (2) are exemplified.

[0233] As PAVE, perfluoro(methyl vinyl ether) (PMVE), perfluoro(ethyl vinyl ether) (PEVE), and perfluoro(propyl vinyl ether) (PPVE) are more preferable, and particularly PMVE is preferable.

[0234] Also, as PAVE, a perfluorovinyl ether represented by the formula: CF2=CFOCF2ORf c (wherein Rf c is a linear or branched perfluoroalkyl group having 1 to 6 carbon atoms, a cyclic perfluoroalkyl group having 5 to 6 carbon atoms, or a linear or branched perfluorooxyalkyl group having 2 to 6 carbon atoms containing 1 to 3 oxygen atoms) can also be used. As PAVE, for example, CF2=CFOCF2OCF3, CF2=CFOCF2OCF2CF3, or CF2=CFOCF2OCF2CF2OCF3 is preferable.

[0235] As the fluorine-containing monomer (2), a monomer in which Rf is a linear fluoroalkyl group is preferable, and a monomer in which Rf is a linear perfluoroalkyl group is more preferable. It is preferable that the number of carbon atoms of Rf is 1 to 6.

[0236] Examples of the fluorine-containing monomer (2) include CH2=CFCF3, CH2=CFCF2CF3, CH2=CFCF2CF2CF3, CH2=CFCF2CF2CF2CF3, CHF=CHCF3 (1,3,3,3-tetrafluoropropene), CHF=CHCF3 (E isomer), CHF=CHCF3 (Z isomer), etc. Among them, 2,3,3,3-tetrafluoropropylene represented by CH2=CFCF3 is preferable.

[0237] In the production method of the present disclosure, since a larger number of fluorine-containing elastomer particles can be generated at a higher polymerization rate while further suppressing the adhesion of the fluorine-containing elastomer to the polymerization tank, it is preferable to polymerize at least vinylidene fluoride or tetrafluoroethylene as the fluorine-containing monomer, and it is more preferable to polymerize vinylidene fluoride.

[0238] In the production method of the present disclosure, a fluorine-free monomer may be polymerized together with the fluorine-containing monomer. Examples of the fluorine-free monomer include α-olefin monomers having 2 to 10 carbon atoms such as ethylene, propylene, butene, and pentene; alkyl vinyl ethers having an alkyl group 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 and compounds can be used in combination.

[0239] According to the manufacturing method of the present disclosure, an aqueous dispersion containing a fluorine-containing elastomer can be produced. As the fluorine-containing elastomer, a partially fluorinated elastomer is preferable because the polymerization of the fluorine-containing monomer proceeds more smoothly, the adhesion of the fluorine-containing elastomer to the polymerization tank is further suppressed, and a larger number of fluorine-containing elastomer particles can be generated at a higher polymerization rate. The partially fluorinated elastomer is a fluoropolymer that contains a fluorine-containing monomer unit and has a content of perfluoromonomer units of less than 90 mol% with respect to all monomer units, has a glass transition temperature of 20°C or lower, and has a melting peak (ΔH) magnitude of 4.5 J / g or less.

[0240] The fluorine-containing elastomer preferably contains a methylene group (-CH2-) in the main chain. The fluorine-containing elastomer (partially fluorinated elastomer) containing -CH2- in the main chain is not particularly limited as long as it contains a chemical structure represented by -CH2-, and examples thereof include fluorine-containing elastomers containing structures such as -CH2-CF2-, -CH2-CH(CH3)-, -CH2-CH2-, -CH2-CF(CF3)-. These can be introduced into the main chain of the fluorine-containing elastomer, for example, by polymerizing vinylidene fluoride, propylene, ethylene, 2,3,3,3-tetrafluoropropylene, etc. The content of tetrafluoroethylene units in the fluorine-containing elastomer (the content of monomer units based on tetrafluoroethylene with respect to all monomer units of the fluorine-containing elastomer) may be less than 40 mol%.

[0241] Examples of the fluorine-containing elastomer include tetrafluoroethylene (TFE), vinylidene fluoride (VdF), and the general formula: CF2=CF-Rf a (wherein, Rf a is -CF3 or -ORf b (Rf bIt preferably contains monomer units based on at least one monomer selected from the group consisting of perfluoroethylene unsaturated compounds represented by a perfluoroalkyl group having 1 to 5 carbon atoms (for example, hexafluoropropylene (HFP), perfluoro(alkyl vinyl ether) (PAVE), etc.). Among fluorine-containing elastomers, it is particularly preferable to contain VdF units or TFE units.

[0242] More specifically, examples of the fluorine-containing elastomer include VdF-based fluorine-containing elastomers, TFE / propylene (Pr)-based fluorine-containing elastomers, TFE / Pr / VdF-based fluorine-containing elastomers, ethylene (Et) / HFP-based fluorine-containing elastomers, Et / HFP / VdF-based fluorine-containing elastomers, Et / HFP / TFE-based fluorine-containing elastomers, Et / TFE / PAVE-based fluorine-containing elastomers, and the like. Among these, VdF-based fluorine-containing elastomers, TFE / Pr-based fluorine-containing elastomers, TFE / Pr / VdF-based fluorine-containing elastomers, or Et / TFE / PAVE-based fluorine-containing elastomers are more preferable in terms of good heat aging resistance and oil resistance.

[0243] A VdF-based fluorine-containing elastomer is a fluorine-containing elastomer having VdF units. In the VdF-based fluorine-containing elastomer, the VdF units are preferably 20 mol% or more and 90 mol% or less, more preferably 40 mol% or more and 85 mol% or less, still more preferably 45 mol% or more and 80 mol% or less, and particularly preferably 50 mol% or more and 80 mol% or less of the total number of moles of the VdF units and monomer units based on other monomers.

[0244] The other monomers in the VdF-based fluorine-containing elastomer are not particularly limited as long as they are monomers copolymerizable with VdF. For example, the above-mentioned fluorine-containing monomers can be used.

[0245] As the VdF-based fluorine-containing elastomer, at least one copolymer selected from the group consisting of a VdF / HFP copolymer, a VdF / TFE / HFP copolymer, a VdF / CTFE copolymer, a VdF / CTFE / TFE copolymer, a VdF / PAVE copolymer, a VdF / TFE / PAVE copolymer, a VdF / HFP / PAVE copolymer, a VdF / HFP / TFE / PAVE copolymer, a VdF / TFE / Pr copolymer, a VdF / Et / HFP copolymer, and a copolymer of VdF and a fluorine-containing monomer (2) is preferred. Further, it is more preferred that it has at least one monomer selected from the group consisting of TFE, HFP, and PAVE as a monomer other than VdF.

[0246] Among these, as the VdF-based fluorine-containing elastomer, at least one copolymer selected from the group consisting of a VdF / HFP copolymer, a VdF / TFE / HFP copolymer, a copolymer of VdF and a fluorine-containing monomer (2), a VdF / PAVE copolymer, a VdF / TFE / PAVE copolymer, a VdF / HFP / PAVE copolymer, and a VdF / HFP / TFE / PAVE copolymer is preferred, and at least one copolymer selected from the group consisting of a VdF / HFP copolymer, a VdF / HFP / TFE copolymer, a copolymer of VdF and a fluorine-containing monomer (2), and a VdF / PAVE copolymer is more preferred.

[0247] As the VdF / PAVE copolymer, those having a VdF / PAVE composition of (65 to 90) / (35 to 10) (mol%) are preferred. Also, a form in which the VdF / PAVE composition is (50 to 78) / (50 to 22) (mol%) is also a preferred form.

[0248] As the VdF / TFE / PAVE copolymer, those having a VdF / TFE / PAVE composition of (40 to 80) / (3 to 40) / (15 to 35) (mol%) are preferred.

[0249] As the VdF / HFP / PAVE copolymer, those having a VdF / HFP / PAVE composition of (65 to 90) / (3 to 25) / (3 to 25) (mol%) are preferred.

[0250] As the VdF / HFP / TFE / PAVE copolymer, those with a composition of VdF / HFP / TFE / PAVE of (40 to 90) / (0 to 25) / (0 to 40) / (3 to 35) (mol%) are preferred, and those with (40 to 80) / (3 to 25) / (3 to 40) / (3 to 25) (mol%) are more preferred.

[0251] As the copolymer of VdF / fluorine-containing monomer (2), those in which the VdF / fluorine-containing monomer (2) units are (85 to 20) / (15 to 80) (mol%), and the other monomer units other than VdF and the fluorine-containing monomer (2) are 0 to 50 mol% of the total monomer units are preferred, and it is more preferred that the molar% ratio of the VdF / fluorine-containing monomer (2) units is (80 to 20) / (20 to 80). Also, a composition where the VdF / fluorine-containing monomer (2) units are (78 to 50) / (22 to 50) (mol%) is also one of the preferred forms.

[0252] Also, as the copolymer of VdF / fluorine-containing monomer (2), those in which the VdF / fluorine-containing monomer (2) units are (85 to 50) / (15 to 50) (mol%), and the other monomer units other than VdF and the fluorine-containing monomer (2) are 1 to 50 mol% of the total monomer units are also preferred. As the other monomers other than VdF and the fluorine-containing monomer (2), the monomers exemplified as other monomers in VdF-based fluorine-containing elastomers such as TFE, HFP, PMVE, perfluoroethyl vinyl ether (PEVE), PPVE, CTFE, trifluoroethylene, hexafluoroisobutene, vinyl fluoride, Et, Pr, alkyl vinyl ether, and monomers that give a crosslinkable group are preferred, and among them, PMVE, CTFE, HFP, and TFE are more preferred.

[0253] The TFE / Pr-based fluorine-containing elastomer refers to a fluorine-containing copolymer composed of 45 to 70 mol% of TFE and 55 to 30 mol% of Pr. In addition to these two components, a specific third component may be included.

[0254] As the specific third component, for example, fluorine-containing olefins other than TFE (such as VdF, HFP, CTFE, perfluoro(butylethylene), etc.), fluorine-containing vinyl ethers (perfluoro(propyl vinyl ether), perfluoro(methyl vinyl ether), etc.) and other fluorine-containing monomers; hydrocarbon monomers such as α-olefins (ethylene, 1-butene, etc.), vinyl ethers (ethyl vinyl ether, butyl vinyl ether, hydroxybutyl vinyl ether, etc.), vinyl esters (vinyl acetate, vinyl benzoate, vinyl crotonate, vinyl methacrylate, etc.); etc. may be included. The above specific third component may be one kind or a combination of two or more kinds.

[0255] The TFE / Pr-based fluorine-containing elastomer preferably contains VdF. Among the TFE / Pr-based fluorine-containing elastomers, an elastomer composed of TFE, Pr, and VdF is referred to as a TFE / Pr / VdF-based fluorine-containing elastomer.

[0256] The TFE / Pr / VdF-based fluorine-containing elastomer may further contain the above specific third component other than VdF. The above specific third component may be one kind or a combination of two or more kinds. In the TFE / Pr-based fluorine-containing elastomer, the total content of the third component is preferably 35 mol% or less, more preferably 33 mol% or less, and still more preferably 31 mol% or less.

[0257] As the Et / HFP copolymer, those with a composition of Et / HFP of (35 to 80) / (65 to 20) (mol%) are preferred, and those with a composition of (40 to 75) / (60 to 25) (mol%) are more preferred.

[0258] For the Et / HFP / TFE copolymer, those with a composition of Et / HFP / TFE of (35 to 75) / (25 to 50) / (0 to 15) (mol%) are preferred, and those with a composition of (45 to 75) / (25 to 45) / (0 to 10) (mol%) are more preferred.

[0259] The Et / TFE / PAVE copolymer preferably has a composition of Et / TFE / PAVE of (10 to 40) / (32 to 60) / (20 to 40) (mol %), more preferably (20 to 40) / (40 to 50) / (20 to 30) (mol %). PMVE is preferred as PAVE.

[0260] As the fluorine-containing elastomer, a fluorine-containing elastomer containing VdF units is preferred, a VdF / HFP copolymer or a VdF / HFP / TFE copolymer is more preferred, and those having a composition of VdF / HFP / TFE of (32 to 85) / (10 to 34) / (0 to 40) (mol %) are particularly preferred. As the composition of VdF / HFP / TFE, (32 to 85) / (15 to 34) / (0 to 34) (mol %) is more preferred, and (47 to 81) / (17 to 32) / (0 to 26) (mol %) is even more preferred.

[0261] For example, in the above VdF / HFP copolymer, the composition of VdF / HFP is preferably (45 to 85) / (15 to 55) (mol %), more preferably (50 to 83) / (17 to 50) (mol %), still more preferably (55 to 81) / (19 to 45) (mol %), and particularly preferably (60 to 80) / (20 to 40) (mol %).

[0262] The above-described configuration is the configuration of the main monomer of the fluorine-containing elastomer. In addition to the main monomer, a monomer that provides a crosslinkable group may be copolymerized. As the monomer that provides a crosslinkable group, any monomer that can introduce an appropriate crosslinkable group into the fluorine-containing elastomer according to the production method and the crosslinking system may be used. For example, known polymerizable compounds containing crosslinkable groups such as iodine atoms, bromine atoms, carbon-carbon double bonds, cyano groups, carboxyl groups, hydroxyl groups, amino groups, and ester groups can be mentioned.

[0263] Preferred monomers that provide a crosslinkable group include the general formula (3): CY 1 2=CY 2 R f 2 X 1 (3) (In the formula, Y1 , Y 2 is a fluorine atom, a hydrogen atom or -CH3; R f 2 may have one or more ether-bonding oxygen atoms, may have an aromatic ring, and is a linear or branched fluorine-containing alkylene group in which some or all of the hydrogen atoms are substituted with fluorine atoms; X 1 is an iodine atom or a bromine atom) Examples include compounds represented by

[0264] Specific examples of the monomer that provides a crosslinkable group include, for example, general formula (4): CY 1 2 = CY 2 R f 3 CHR 1 -X 1 (4) (In the formula, Y 1 , Y 2 , X 1 are the same as described above, and R f 3 may have one or more ether-bonding oxygen atoms and is a linear or branched fluorine-containing alkylene group in which some or all of the hydrogen atoms are substituted with fluorine atoms, that is, a linear or branched fluorine-containing alkylene group in which some or all of the hydrogen atoms are substituted with fluorine atoms, a linear or branched fluorine-containing oxyalkylene group in which some or all of the hydrogen atoms are substituted with fluorine atoms, or a linear or branched fluorine-containing polyoxyalkylene group in which some or all of the hydrogen atoms are substituted with fluorine atoms; R 1 is a hydrogen atom or a methyl group) Examples include iodine- or bromine-containing monomers represented by CY 4 2 = CY 4 (CF2) n -X 1 (5) (In the formula, Y 4 is the same or different and is a hydrogen atom or a fluorine atom, and n is an integer from 1 to 8) CF2 = CFCF2R f 4 -X 1 (6) (wherein, R 4 is -(OCF2) n - or -(OCF(CF3)) n - and n is an integer from 0 to 5) CF2=CFCF2(OCF(CF3)CF2) m (OCH2CF2CF2) n OCH2CF2-X 1 (7) (wherein, m is an integer from 0 to 5 and n is an integer from 0 to 5) CF2=CFCF2(OCH2CF2CF2) m (OCF(CF3)CF2) n OCF(CF3)-X 1 (8) (wherein, m is an integer from 0 to 5 and n is an integer from 0 to 5) CF2=CF(OCF2CF(CF3)) m O(CF2) n -X 1 (9) (wherein, m is an integer from 0 to 5 and n is an integer from 1 to 8) CF2=CF(OCF2CF(CF3)) m -X 1 (10) (wherein, m is an integer from 1 to 5) CF2=CFOCF2(CF(CF3)OCF2) n CF(-X 1 )CF3(11) (wherein, n is an integer from 1 to 4) CF2=CFO(CF2) n OCF(CF3)-X 1 (12) (wherein, n is an integer from 2 to 5) CF2=CFO(CF2) n -(C6H4)-X 1 (13) (wherein, n is an integer from 1 to 6) CF2=CF(OCF2CF(CF3)) n OCF2CF(CF3)-X 1 (14) (wherein, n is an integer from 1 to 2) CH2=CFCF2O(CF(CF3)CF2O) nCF(CF3)-X 1 (15) (wherein n is an integer from 0 to 5), CF2=CFO(CF2CF(CF3)O) m (CF2) n -X 1 (16) (wherein m is an integer from 0 to 5 and n is an integer from 1 to 3) CH2=CFCF2OCF(CF3)OCF(CF3)-X 1 (17) CH2=CFCF2OCH2CF2-X 1 (18) CF2=CFO(CF2CF(CF3)O) m CF2CF(CF3)-X 1 (19) (wherein m is an integer of 0 or more) CF2=CFOCF(CF3)CF2O(CF2) n -X 1 (20) (wherein n is an integer of 1 or more) CF2=CFOCF2OCF2CF(CF3)OCF2-X 1 (21) CH2=CH-(CF2) n X 1 (22) (wherein n is an integer from 2 to 8) (In general formulas (5) to (22), X 1 is the same as described above) Examples include iodine- or bromine-containing monomers represented by these, and these can be used alone or in any combination.

[0265] Examples of the iodine- or bromine-containing monomer represented by general formula (4) include general formula (23):

Chemical formula

Chemical formula

[0266] More specifically, as the iodine or bromine-containing monomer represented by the general formula (5), ICF2CF2CF=CH2 and I(CF2CF2)2CF=CH2 are preferably cited.

[0267] More specifically, as the iodine or bromine-containing monomer represented by the general formula (9), I(CF2CF2)2OCF=CF2 is preferably cited.

[0268] More specifically, as the iodine or bromine-containing monomer represented by the general formula (22), CH2=CHCF2CF2I and I(CF2CF2)2CH=CH2 are preferably cited.

[0269] Also, the formula: R 2 R 3 C=CR 4 -Z-CR 5 =CR 6 R 7 (In the formula, R 2 , R 3 , R 4 , R 5 , R 6 and R 7 are the same or different, and each is H or an alkyl group having 1 to 5 carbon atoms; Z is a linear or branched alkylene or cycloalkylene group having 1 to 18 carbon atoms which may contain an oxygen atom and is preferably at least partially fluorinated, or a (per)fluoropolyoxyalkylene group), and the bisolefin compound represented by this is also preferable as a monomer giving a crosslinkable group. In the present disclosure, the "(per)fluoropolyoxyalkylene group" means a "fluoropolyoxyalkylene group or perfluoropolyoxyalkylene group".

[0270] Z is preferably a (per)fluoroalkylene group having 4 to 12 carbon atoms, and R 2 , R 3 , R4 , R 5 , R 6 and R 7 are preferably hydrogen atoms.

[0271] When Z is a (per)fluoropolyoxyalkylene group, the formula: -(Q) p -CF2O-(CF2CF2O) m -(CF2O) n -CF2-(Q) p - (wherein Q is an alkylene group having 1 to 10 carbon atoms or an oxyalkylene group having 2 to 10 carbon atoms, p is 0 or 1, and m and n are such that the m / n ratio is 0.2 to 5 and the molecular weight of the (per)fluoropolyoxyalkylene group is in the range of 500 to 10,000, preferably 1000 to 4000. ) is preferably a (per)fluoropolyoxyalkylene group represented by. In this formula, Q is preferably selected from -CH2OCH2- and -CH2O(CH2CH2O) s CH2-(s = 1 to 3).

[0272] Preferred bisolefins are CH2=CH-(CF2)2-CH=CH2, CH2=CH-(CF2)4-CH=CH2, CH2=CH-(CF2)6-CH=CH2, the formula: CH2=CH-Z 1 -CH=CH2 (wherein Z 1 is -CH2OCH2-CF2O-(CF2CF2O) m -(CF2O) n -CF2-CH2OCH2-(m / n is 0.5, the molecular weight is preferably 2000)) and the like.

[0273] Among them, 3,3,4,4,5,5,6,6,7,7,8,8-dodecafluoro-1,9-decadiene represented by CH2=CH-(CF2)6-CH=CH2 is preferred.

[0274] The number average molecular weight Mn of the fluorine-containing elastomer is preferably from 1,000 to 1,000,000, more preferably from 10,000 to 500,000, and particularly preferably from 20,000 to 300,000.

[0275] The fluorine-containing elastomer preferably has a fluorine content of 50% by mass or more, more preferably 55% by mass or more, and still more preferably 60% by mass or more. The upper limit of the fluorine content is preferably 75% by mass or less, and more preferably 73% by mass or less. The fluorine content is 19 calculated based on the measured values by F-NMR and 1 H-NMR, elemental analysis, etc.

[0276] The fluorine-containing elastomer preferably has a Mooney viscosity (ML1+10(100°C)) at 100°C of 130 or less. The above Mooney viscosity is more preferably 110 or less, and still more preferably 90 or less. Also, the above Mooney viscosity is more preferably 10 or more, and still more preferably 20 or more. Here, the Mooney viscosity is a value measured in accordance with JIS K 6300-1.2013.

[0277] The fluorine-containing elastomer preferably has a glass transition temperature of -50 to 0°C. The above glass transition temperature is more preferably -2°C or less, and still more preferably -3°C or less. Also, the above glass transition temperature is more preferably -45°C or more, and still more preferably -40°C or more. The above glass transition temperature may be -10°C or more, or -9°C or more. Here, the glass transition temperature can be obtained by using a differential scanning calorimeter (for example, X-DSC7000 manufactured by Hitachi High-Tech Science Corporation), obtaining a DSC curve by heating 10 mg of the sample at 20°C / min, and determining the glass transition temperature from the DSC differential curve in accordance with JISK6240:2011.

[0278] The fluorine-containing elastomer preferably has an iodine content of 0.05 to 1.0% by mass. The iodine content is more preferably 0.08% by mass or more, still more preferably 0.10% by mass or more, and more preferably 0.80% by mass or less, still more preferably 0.60% by mass or less.

[0279] The iodine content can be determined by elemental analysis. Specifically, 5 mg of Na2SO3 is mixed with 12 mg of the fluorine-containing elastomer, and 30 mg of an absorbent solution prepared by dissolving a mixture of Na2CO3 and K2CO3 in a 1:1 (mass ratio) in 20 ml of pure water is used. It is burned in oxygen in a quartz flask, left standing for 30 minutes, and then can be measured using a Shimadzu 20A ion chromatograph. As the calibration curve, a KI standard solution, a solution containing 0.5 ppm by mass of iodine ions, and a solution containing 1.0 ppm by mass of iodine ions can be used.

[0280] The fluorine-containing elastomer preferably contains a -CH2I structure. The inclusion of a -CH2I structure can be 1 confirmed by 1H-NMR spectrum. The fluorine-containing elastomer containing a -CH2I structure can be obtained by iodine transfer polymerization.

[0281] In the fluorine-containing elastomer, the amount of the -CH2I structure relative to 100 mol% of the -CH2- structure is preferably 0.05 to 1.50 mol%. The amount of the -CH2I structure is more preferably 0.08 mol% or more, still more preferably 0.12 mol% or more, more preferably 1.20 mol% or less, still more preferably 1.00 mol% or less, and particularly preferably 0.80 mol% or less. The amount of the -CH2I structure can be 1 determined by 1H-NMR spectrum.

[0282] The fluorine-containing elastomer more preferably contains a -CF2CH2I structure. The fluorine-containing elastomer containing a -CF2CH2I structure can be obtained by producing a VdF-based fluorine-containing elastomer by iodine transfer polymerization.

[0283] The fluorine-containing elastomer preferably has an amount of -CF2CH2I structure of 0.05 to 1.50 mol% based on 100 mol% of the -CH2- structure. The amount of the -CF2CH2I structure is more preferably 0.08 mol% or more, still more preferably 0.12 mol% or more, more preferably 1.20 mol% or less, still more preferably 1.00 mol% or less, and particularly preferably 0.80 mol% or less. The amount of the -CF2CH2I structure is 1 calculated by A / B * 100, where A is the integrated value of the total peak intensities observed in the region of the chemical shift of 3.75 to 4.05 ppm derived from -CH2I and B is the integrated value of the total peak intensities observed in the regions of the chemical shifts of 2.3 to 2.7 ppm and 2.9 to 3.75 ppm derived from -CH2- in the 1H-NMR spectrum.

[0284] As the fluorine-containing monomer used in the production method of the present disclosure, the fluorine-containing monomers described for the fluorine-containing elastomer can be appropriately used.

[0285] According to the production method of the present disclosure, an aqueous dispersion of a fluorine-containing elastomer can be obtained. The solid content concentration (content of the fluorine-containing elastomer) of the obtained aqueous dispersion of the fluorine-containing elastomer is preferably 10 to 50% by mass, more preferably 15 to 40% by mass, and still more preferably 20 to 30% by mass at the time when the polymerization is completed.

[0286] The solid content concentration (content of the fluorine-containing elastomer) of the aqueous dispersion of the fluorine-containing elastomer can be specified by drying 1 g of the aqueous dispersion under the conditions of 150 °C for 180 minutes, measuring the mass of the heat residue, and calculating the ratio of the mass of the heat residue to the mass of the aqueous dispersion.

[0287] The aqueous dispersion of the fluorine-containing elastomer may contain fluorine-containing elastomer particles. The average particle diameter of the fluorine-containing elastomer particles is preferably 10 to 800 nm, more preferably 50 to 500 nm, and still more preferably 70 to 300 nm. The average particle diameter of the fluorine-containing elastomer particles is the cumulative average diameter and can be measured by the dynamic light scattering method.

[0288] The number of fluorine-containing elastomer particles contained in the aqueous dispersion of the fluorine-containing elastomer is preferably 1.0×10 12 particles / cc or more, more preferably 5.0×10 12 particles / cc or more, still more preferably 1.0×10 13 particles / cc or more. The above particle number (the number of polymer particles) can be calculated according to the following formula.

[0289]

Number

[0290] Processing such as coagulation and heating may be performed on the aqueous dispersion of the fluorine-containing elastomer.

[0291] The above coagulation can be carried out by adding alkaline earth and earth metal salts to the aqueous dispersion. Examples of the alkaline earth and earth metal salts include sulfates, nitrates, hydrochlorides, acetates, etc. of calcium, magnesium, aluminum, etc.

[0292] The coagulated fluorine-containing elastomer may be washed with water to remove impurities such as a small amount of buffer solution and salt present in the fluorine-containing elastomer, and then the washed fluorine-containing elastomer may be dried. The drying temperature is preferably 40 to 200°C, more preferably 60 to 180°C, and still more preferably 80 to 150°C.

[0293] The form of the fluorine-containing elastomer obtained after coagulation is not particularly limited, and may be gum, crumb, powder, pellet, etc., and is preferably gum or crumb. A gum is a small granular mass of a fluorine-containing elastomer, and a crumb is an amorphous mass of a fluorine-containing elastomer that cannot maintain its small granular shape as a gum at room temperature and is fused to each other. The gum or crumb is preferably obtained by coagulating, drying, etc., the aqueous dispersion obtained by the production method of the present disclosure by a conventionally known method.

[0294] The polymer (1), decomposition products and by-products of the polymer (1) produced as by-products from the polymer (1), residual monomers, etc. may be recovered and purified from the wastewater generated by the coagulation or washing and / or the off-gas generated by drying, to thereby reuse the polymer (1), decomposition products and by-products of the polymer (1) produced as by-products from the polymer (1), residual monomers, etc. The method for the recovery and purification is not particularly limited, and can be carried out by a known method. For example, it can be carried out by the method described in JP-A-2011-520020.

[0295] The method for recovering and purifying the polymer (1), decomposition products and by-products of the polymer (1) produced as by-products from the polymer (1), residual monomers, etc. from the wastewater generated by the coagulation, the wastewater generated by washing, and the off-gas generated by drying is not particularly limited, and any conventionally known method can be used, such as those described in U.S. Patent Application Publication No. 2007 / 0015937, U.S. Patent Application Publication No. 2007 / 0025902, and U.S. Patent Application Publication No. 2007 / 0027251. Specifically, the following method can be used.

[0296] As a method for recovering the polymer (1), decomposition products and by-products of the polymer (1) by-produced from the polymer (1), residual monomers, etc. from the above-mentioned wastewater, adsorption particles such as ion exchange resins, activated carbon, silica gel, clay, zeolite, etc. are brought into contact with the wastewater to adsorb the polymer (1), etc., and then a method of separating the wastewater and the adsorption particles can be mentioned. If the adsorption particles adsorbed with the polymer (1), etc. are incinerated, the release of the polymer (1), etc. into the environment can be prevented.

[0297] In addition, the polymer (1), etc. can also be recovered by desorbing and eluting the polymer (1), etc. from the ion exchange resin particles adsorbed with the polymer (1), etc. by a known method. For example, when the ion exchange resin particles are anion exchange resin particles, the polymer (1), etc. can be eluted by bringing a mineral acid into contact with the anion exchange resin. Subsequently, when a water-soluble organic solvent is added to the obtained eluate, it usually separates into two phases, so the polymer (1), etc. can be recovered by recovering and neutralizing the lower phase containing the polymer (1), etc. Examples of the water-soluble organic solvent include polar solvents such as alcohols, ketones, and ethers.

[0298] Another method for recovering the polymer (1), etc. from the ion exchange resin particles includes a method using an ammonium salt and a water-soluble organic solvent, and a method using an alcohol and, if desired, an acid. In the latter method, an ester derivative of the polymer (1), etc. is generated, so it can be easily separated from the alcohol by distillation.

[0299] When the above-mentioned wastewater contains fluorine-containing elastomer particles or other solid components, it is preferable to remove them before bringing the wastewater and the adsorption particles into contact. Examples of the method for removing the fluorine-containing elastomer particles and other solid components include a method of adding an aluminum salt, etc. to precipitate them and then separating the wastewater and the precipitate, an electrocoagulation method, etc. Also, it may be removed by a mechanical method, for example, a cross-flow filtration method, a deep filtration method, a precoat filtration method.

[0300] The concentration of the unaggregated fluorine-containing elastomer in the above-mentioned drainage is preferably low from the viewpoint of productivity, more preferably less than 0.4% by mass, and particularly preferably less than 0.3% by mass.

[0301] As a method for recovering the polymer (1) and the like from the above-mentioned off-gas, there is a method of using a scrubber to contact with deionized water, an alkaline aqueous solution, an organic solvent such as a glycol ether solvent, etc., to obtain a scrubber solution containing the polymer (1) and the like. When a high-concentration alkaline aqueous solution is used as the alkaline aqueous solution, the scrubber solution can be recovered with the polymer (1) and the like in a phase-separated state, so that the recovery and reuse of the polymer (1) and the like are easy. Examples of the alkaline compound include alkali metal hydroxides and quaternary ammonium salts.

[0302] The scrubber solution containing the polymer (1) and the like may be concentrated using a reverse osmosis membrane or the like. The concentrated scrubber solution usually contains fluoride ions, but by further adding alumina after concentration to remove the fluoride ions, the reuse of the polymer (1) and the like can also be facilitated. Further, adsorbent particles may be brought into contact with the scrubber solution to adsorb the polymer (1) and the like, and the polymer (1) and the like may be recovered by the method described above.

[0303] The polymer (1) and the like recovered by any of the above methods can be reused in the production of the fluorine-containing elastomer.

[0304] By adding a crosslinking agent or the like to the aqueous dispersion of the fluorine-containing elastomer or the fluorine-containing elastomer obtained by the production method of the present disclosure, a crosslinkable composition can be produced. The type and amount of the crosslinking agent are not particularly limited and can be used within a known range.

[0305] When the fluorine-containing elastomer is an uncrosslinked elastomer, examples of its crosslinking system include a peroxide crosslinking system, a polyol crosslinking system, a polyamine crosslinking system, etc., and it is 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, the peroxide crosslinking system is preferred, and from the perspective of heat resistance, the polyol crosslinking system is preferred.

[0306] Therefore, as the above crosslinking agent, at least one crosslinking agent selected from the group consisting of a polyol crosslinking agent and a peroxide crosslinking agent is preferred, and a peroxide crosslinking agent is more preferred.

[0307] The compounding amount of the crosslinking agent may be appropriately selected depending on the type of the crosslinking agent, etc., but it is preferably 0.2 to 6.0 parts by mass, more preferably 0.3 to 5.0 parts by mass, based on 100 parts by mass of the fluorine-containing elastomer.

[0308] Peroxide crosslinking can be carried out by using an uncrosslinked elastomer capable of peroxide crosslinking as the fluorine-containing elastomer and an organic peroxide as the crosslinking agent.

[0309] The uncrosslinked elastomer capable of peroxide crosslinking is not particularly limited as long as it is an uncrosslinked elastomer having a site capable of peroxide crosslinking. The site capable of peroxide crosslinking is not particularly limited, and examples thereof include a site having an iodine atom, a site having a bromine atom, etc.

[0310] The organic peroxide may be any organic peroxide that can easily generate peroxy radicals in the presence of heat or an oxidation-reduction system. Examples include 1,1-bis(t-butylperoxy)-3,5,5-trimethylcyclohexane, 2,5-dimethylhexane-2,5-dihydroperoxide, di-t-butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, α,α-bis(t-butylperoxy)-p-diisopropylbenzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)-hexyne-3, benzoyl peroxide, t-butyl peroxybenzene, t-butyl peroxymaleic acid, t-butyl peroxyisopropyl carbonate, t-butyl peroxybenzoate, and the like. Among these, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane and 2,5-dimethyl-2,5-di(t-butylperoxy)-hexyne-3 are preferred.

[0311] The compounding amount of the organic peroxide is preferably 0.1 to 15 parts by mass, more preferably 0.3 to 5 parts by mass, based on 100 parts by mass of the fluorine-containing elastomer.

[0312] When the crosslinking agent is an organic peroxide, it is preferable that the fluorine-containing elastomer composition further contains a crosslinking aid. Examples of the crosslinking aid include triallyl cyanurate, triallyl isocyanurate (TAIC), triacryl formal, triallyl trimellitate, N,N′-m-phenylene bismaleimide, dipropynyl terephthalate, diallyl phthalate, tetraallyl terephthalamide, triallyl phosphate, bismaleimide, fluorinated triallyl isocyanurate (1,3,5-tris(2,3,3-trifluoro-2-propenyl)-1,3,5-triazine-2,4,6-trione), tris(diallylamine)-S-triazine, N,N-diallylacrylamide, 1,6-divinyldodecafluorohexane, hexaallyl phosphoramide, N,N,N′,N′-tetraallylphthalamide, N,N,N′,N′-tetraallylmalonamide, trivinyl isocyanurate, 2,4,6-trivinylmethyltrisiloxane, tri(5-norbornene-2-methylene) cyanurate, triallyl phosphite, trimethaallyl isocyanurate, and the like. Among these, triallyl isocyanurate (TAIC) is preferable in terms of excellent crosslinkability, mechanical properties, and flexibility.

[0313] The compounding amount of the crosslinking aid is preferably 0.01 to 10 parts by mass, more preferably 0.01 to 7.0 parts by mass, and still more preferably 0.1 to 5.0 parts by mass with respect to 100 parts by mass of the fluorine-containing elastomer. When the crosslinking aid is less than 0.01 part by mass, the mechanical properties or flexibility may decrease. When it exceeds 10 parts by mass, the heat resistance is inferior and the durability of the molded product also tends to decrease.

[0314] Polyol crosslinking can be carried out by using an uncrosslinked elastomer capable of polyol crosslinking as a fluorine-containing elastomer and a polyhydroxy compound as a crosslinking agent. In the polyol crosslinking system, the blending amount of the polyhydroxy compound is preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of the uncrosslinked elastomer capable of polyol crosslinking. When the blending amount of the polyhydroxy compound is within such a range, polyol crosslinking can proceed sufficiently. More preferably, it is 0.02 to 8 parts by mass. Even more preferably, it is 0.03 to 4 parts by mass.

[0315] The uncrosslinked elastomer capable of polyol crosslinking is not particularly limited as long as it is an uncrosslinked elastomer having a site capable of polyol crosslinking. The site capable of polyol crosslinking is not particularly limited, and examples thereof include a site having a vinylidene fluoride (VdF) unit. Examples of the method for introducing the crosslinking site include a method of copolymerizing a monomer that gives a crosslinking site during the polymerization of the uncrosslinked elastomer.

[0316] As the polyhydroxy compound, a polyhydroxy aromatic compound is preferably used from the viewpoint of excellent heat resistance.

[0317] The above polyhydroxy aromatic compound is not particularly limited. For example, 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 from, for example, Fujifilm Wako Pure Chemical Corporation, Central Glass Co., Ltd., etc.), 1,3-dihydroxybenzene, 1,7-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 4,4'-dihydroxydiphenyl, 4,4'-dihydroxystilbene, 2,6-dihydroxyanthracene, hydroquinone, catechol, 2,2-bis(4-hydroxyphenyl)butane (hereinafter referred to as bisphenol B), 4,4-bis(4-hydroxyphenyl)valeric acid, 2,2-bis(4-hydroxyphenyl)tetrafluorodichloropropane, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl ketone, tris(4-hydroxyphenyl)methane, 3,3',5,5'-tetrachlorobisphenol A, 3,3',5,5'-tetrabromobisphenol A, and the like. These polyhydroxy aromatic compounds may be alkali metal salts, alkaline earth metal salts, etc. However, when the copolymer is coagulated using an acid, it is preferable not to use the above metal salts. The compounding amount of the polyhydroxy aromatic compound is 0.1 to 15 parts by mass, preferably 0.5 to 5 parts by mass, based on 100 parts by mass of the uncrosslinked elastomer.

[0318] When the crosslinking agent is a polyhydroxy compound, it is preferable that the above fluorine-containing elastomer composition further contains a crosslinking accelerator. The crosslinking accelerator promotes the formation of intramolecular double bonds in the dehydrofluorination reaction of the polymer main chain and the addition of the polyhydroxy compound to the generated double bonds.

[0319] In addition, the crosslinking accelerator may be further used in combination with an acid acceptor such as magnesium oxide or a crosslinking aid.

[0320] Examples of the crosslinking accelerator include onium compounds. Among the onium compounds, at least one selected from the group consisting of ammonium compounds such as quaternary ammonium salts, phosphonium compounds such as quaternary phosphonium salts, oxonium compounds, sulfonium compounds, cyclic amines, and monofunctional amine compounds is preferable, and at least one selected from the group consisting of quaternary ammonium salts and quaternary phosphonium salts is more preferable.

[0321] The quaternary ammonium salts are not particularly limited. For example, 8-methyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, 8-methyl-1,8-diazabicyclo[5,4,0]-7-undecenium iodide, 8-methyl-1,8-diazabicyclo[5,4,0]-7-undecenium hydroxide, 8-methyl-1,8-diazabicyclo[5,4,0]-7-undecenium methyl sulfate, 8-ethyl-1,8-diazabicyclo[5,4,0]-7-undecenium bromide, 8-propyl-1,8-diazabicyclo[5,4,0]-7-undecenium bromide, 8-dodecyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, 8-dodecyl-1,8-diazabicyclo[5,4,0]-7-undecenium hydroxide, 8-eicosyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, 8-tetracosyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, 8-benzyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride (hereinafter referred to as DBU-B. DBU-B can be obtained from, for example, Fujifilm Wako Pure Chemical Corporation, etc.), 8-benzyl-1,8-diazabicyclo[5,4,0]-7-undecenium hydroxide, 8-phenethyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, 8-(3-phenylpropyl)-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, tetrabutylammonium hydrogen sulfate, tetrabutylammonium hydroxide, tetrabutylammonium chloride, tetrabutylammonium bromide, etc. can be mentioned. Among these, DBU-B is preferred from the viewpoints of crosslinkability, mechanical properties, and flexibility.

[0322] The quaternary phosphonium salt is not particularly limited. For example, tetrabutylphosphonium chloride, benzyltriphenylphosphonium chloride (hereinafter referred to as BTPPC), benzyltrimethylphosphonium chloride, benzyltributylphosphonium chloride, tributylallylphosphonium chloride, tributyl-2-methoxypropylphosphonium chloride, benzylphenyl(dimethylamino)phosphonium chloride, etc. can be mentioned. Among these, benzyltriphenylphosphonium chloride (BTPPC) is preferred from the viewpoints of crosslinkability, mechanical properties, and flexibility.

[0323] In addition, as the crosslinking accelerator, a solid solution of a quaternary ammonium salt and bisphenol AF, a solid solution of a quaternary phosphonium salt and bisphenol AF, or a chlorine-free crosslinking accelerator disclosed in JP-A-11-147891 can also be used.

[0324] The compounding amount of the crosslinking accelerator is preferably 0.01 to 8.00 parts by mass, more preferably 0.02 to 5.00 parts by mass, and even more preferably 0.03 to 3.00 parts by mass, based on 100 parts by mass of the uncrosslinked elastomer. If the crosslinking accelerator is less than 0.01 part by mass, the crosslinking of the uncrosslinked elastomer may not proceed sufficiently, and the heat resistance of the resulting molded product may decrease. If it exceeds 8.00 parts by mass, the moldability of the fluorine-containing elastomer composition may decrease, the elongation in mechanical properties may decrease, and the flexibility may also tend to decrease.

[0325] The acid acceptor is used to neutralize the acidic substances generated during the polyol crosslinking. 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, litharge (lead oxide), zinc white, dibasic lead phosphite, hydrotalcite, etc. It is preferably at least one selected from the group consisting of highly active magnesium oxide and low-activity magnesium.

[0326] Polyamine crosslinking can be carried out by using a polyamine-crosslinkable fluorine-containing elastomer as the fluorine-containing elastomer and a polyamine compound as the crosslinking agent.

[0327] The polyamine-crosslinkable fluorine-containing elastomer is not particularly limited as long as it is a fluorine-containing elastomer having a polyamine-crosslinkable site. The polyamine-crosslinkable site is not particularly limited, and examples thereof include a site having a vinylidene fluoride (VdF) unit. Examples of the method for introducing the crosslinking site include copolymerizing a monomer that provides a crosslinking site during the polymerization of the fluorine-containing elastomer.

[0328] Examples of the polyamine compound include hexamethylenediamine carbamate, N,N'-dicyclohexylidene-1,6-hexamethylenediamine, 4,4'-bis(aminocyclohexyl)methane carbamate, etc. Among these, N,N'-dicyclohexylidene-1,6-hexamethylenediamine is preferred.

[0329] The method for obtaining the crosslinkable composition is not particularly limited as long as it can uniformly mix the fluorine-containing elastomer obtained by the production method of the present disclosure and the crosslinking agent. For example, a method of kneading a powder obtained by coagulating the fluorine-containing elastomer alone and, if necessary, other additives and compounding agents with a kneader such as an open roll can be mentioned.

[0330] The present disclosure also relates to a composition containing a fluorine-containing elastomer and a polymer (1) containing a polymerization unit (1) based on the monomer (1) represented by the general formula (1). CF2=CF-R-CZ 1 Z 2 -COOM (1) (In the formula, R is a linking group, and Z 1 and Z 2 are each independently F or CF3, and M is H, a metal atom, NR 74. It may be imidazolium which may have a substituent, pyridinium which may have a substituent, or phosphonium which may have a substituent, and R 7 is H or an organic group.)

[0331] The preferred configuration of the fluorine-containing elastomer is the same as that of the fluorine-containing elastomer obtained by the production method of the present disclosure.

[0332] The preferred configuration of the polymer (1) is the same as that of the polymer (1) used in the production method of the present disclosure.

[0333] The form of the composition of the present disclosure is not particularly limited, and may be, for example, an aqueous dispersion, a gum, a clam, a powder, a pellet, etc. An aqueous dispersion is a dispersion system in which an aqueous medium is a dispersion medium and a fluorine-containing elastomer is a dispersed substance. The above aqueous medium is not particularly limited as long as it is a liquid containing water, and in addition to water, it may contain, for example, an organic solvent such as alcohol, ether, ketone, paraffin wax.

[0334] The lower limit of the content of the polymer (1) in the above composition is preferably 0.00001% by mass, more preferably 0.0001% by mass, still more preferably 0.001% by mass, and particularly preferably 0.01% by mass with respect to the fluorine-containing elastomer. The upper limit of the content of the polymer (1) in the above composition is preferably 20% by mass, more preferably 10% by mass, still more preferably 6% by mass, even more preferably 4% by mass, and most preferably 2% by mass or less.

[0335] The content of the polymer (1) in the above composition is, for example, solid 19It can be determined by F-MAS NMR measurement. As a method for measuring the content of polymer (1), the measurement methods of the respective polymers described in WO 2014 / 099453, WO 2010 / 075497, WO 2010 / 075496, WO 2011 / 008381, WO 2009 / 055521, WO 1987 / 007619, JP-A-61-293476, WO 2010 / 075494, WO 2010 / 075359, WO 2006 / 119224, WO 2013 / 085864, WO 2012 / 082707, WO 2012 / 082703, WO 2012 / 082454, WO 2012 / 082451, WO 2006 / 135825, WO 2004 / 067588, WO 2009 / 068528, JP-A-2004-075978, JP-A-2001-226436, WO 1992 / 017635, WO 2014 / 069165, JP-A-11-181009, etc. are described. As a specific apparatus, AVANCE III HD400 manufactured by Bruker, AVANCE300 manufactured by Bruker, etc. can be used. The rotation speed is set according to the resonance frequency of the apparatus so that the spinning sideband does not overlap with the peak used for calculating the content of the fluorine-containing elastomer or polymer (1).

[0336] Also, the content of polymer (1) in the above composition may be measured by the following method. The above composition is mixed with a solvent that dissolves the fluorine-containing elastomer, and in order to extract polymer (1) from the obtained mixed solution, the obtained mixed solution is dropped into deionized water, the aqueous phase containing polymer (1) is recovered, and the content of polymer (1) can be measured by a method of measuring the mass of the residue (polymer (1)) obtained by heating and drying the recovered aqueous phase to calculate the content of polymer (1).

[0337] Examples of the solvent for dissolving the fluorine-containing elastomer include ketone solvents, ether solvents, ester solvents, and perfluorobenzene. As the ketone solvent, acetone is preferable. As the ether solvent, tetrahydrofuran is preferable. As the ester solvent, ethyl acetate is preferable.

[0338] The composition of the present disclosure may be an aqueous dispersion containing a fluorine-containing elastomer, polymer (1), and an aqueous medium. The upper limit of the solid content concentration of the aqueous dispersion is preferably 50% by mass, more preferably 40% by mass, still more preferably 35% by mass, and particularly preferably 30% by mass with respect to the aqueous dispersion. The lower limit of the solid content concentration of the aqueous dispersion is preferably 5% by mass, more preferably 10% by mass, still more preferably 15% by mass, and particularly preferably 20% by mass. The solid content concentration of the aqueous dispersion can be adjusted by diluting or concentrating the aqueous dispersion obtained by polymerization.

[0339] The solid content concentration of the aqueous dispersion is the concentration of the solid content contained in the aqueous dispersion. Examples of the solid content include the fluorine-containing elastomer, polymer (1), and the like. Further, the solid content concentration of the aqueous dispersion may be the total content of the fluorine-containing elastomer and polymer (1) in the aqueous dispersion. The solid content concentration of the aqueous dispersion can be specified by drying 1 g of the aqueous dispersion under the conditions of 150 °C for 180 minutes, measuring the mass of the heat residue, and calculating the ratio of the mass of the heat residue to the mass of the aqueous dispersion.

[0340] The composition of the present disclosure preferably does not substantially contain a fluorine-containing surfactant.

[0341] In the present disclosure, "substantially free of fluorosurfactants" means that the content ratio of fluorosurfactants in the fluorine-containing elastomer is 10 ppm by mass or less. The content ratio of fluorosurfactants is preferably 1 ppm by mass or less, more preferably 100 ppb by mass or less, still more preferably 10 ppb by mass or less, yet still more preferably 1 ppb by mass or less, and particularly preferably, the content ratio of fluorosurfactants measured by liquid chromatography-mass spectrometry (LC / MS) is below the detection limit.

[0342] The content ratio of fluorosurfactants can be quantified by known methods, for example, it can be quantified by LC / MS analysis.

[0343] First, an organic solvent such as methanol is added to the obtained aqueous dispersion, powder, pellet, molded article, or pulverized product obtained by pulverizing the pellet, molded article or molded article to extract the fluorosurfactant, and the extract is subjected to LC / MS analysis. Molecular weight information is extracted from the obtained LC / MS spectrum, and the agreement with the structural formula of the candidate surfactant is confirmed. The extraction method may be the Soxhlet extraction method.

[0344] Thereafter, an aqueous solution with a concentration of 5 levels or more of the confirmed surfactant is prepared, LC / MS analysis is performed for each concentration, and a calibration curve with the area is created.

[0345] That is, the content of fluorosurfactants can be measured, for example, by adding methanol to the composition, performing extraction, and subjecting the obtained extract to LC / MS analysis. In order to further improve the extraction efficiency, treatments such as Soxhlet extraction and ultrasonic treatment may be performed. Molecular weight information is extracted from the obtained LC / MS spectrum, and the agreement with the structural formula of the candidate fluorosurfactant is confirmed. After that, an aqueous solution with a content of the confirmed fluorine-containing surfactant at 5 levels or more is prepared, LC / MS analysis of the aqueous solution with each content is performed, the relationship between the content and the area corresponding to the content is plotted, and a calibration curve is drawn. Then, using the calibration curve, the area of the LC / MS chromatogram of the fluorine-containing surfactant in the extract can be converted to the content of the fluorine-containing surfactant.

[0346] The fluorine-containing surfactant is the same as those exemplified in the production method of the present disclosure described above. For example, it may be a surfactant containing fluorine atoms with a total carbon number of 20 or less in the part excluding the anionic group, it may be a surfactant containing fluorine with an anionic part having a molecular weight of 800 or less, and it may be a fluorine-containing surfactant with a LogPOW of 3.5 or less.

[0347] Examples of the anionic fluorine-containing surfactant include compounds represented by the general formula (N 0 ), specifically, compounds represented by the general formula (N 1 ), compounds represented by the general formula (N 2 ), compounds represented by the general formula (N 3 ), compounds represented by the general formula (N 4 ), and compounds represented by the general formula (N 5Examples of the compound represented by ( ) include. More specifically, perfluorocarboxylic acid (I) represented by general formula (I), ω-H perfluorocarboxylic acid (II) represented by general formula (II), perfluoroether carboxylic acid (III) represented by general formula (III), perfluoroalkyl alkylene carboxylic acid (IV) represented by general formula (IV), perfluoroalkoxyfluorocarboxylic acid (V) represented by general formula (V), perfluoroalkylsulfonic acid (VI) represented by general formula (VI), ω-H perfluorosulfonic acid (VII) represented by general formula (VII), perfluoroalkyl alkylene sulfonic acid (VIII) represented by general formula (VIII), alkyl alkylene carboxylic acid (IX) represented by general formula (IX), fluorocarboxylic acid (X) represented by general formula (X), alkoxyfluorosulfonic acid (XI) represented by general formula (XI), compound (XII) represented by general formula (XII), compound (XIII) represented by general formula (XIII), and the like.

[0348] The composition of the present disclosure can preferably be produced by the production method of the present disclosure.

[0349] The present disclosure also relates to a crosslinkable composition containing the above composition and a crosslinking agent. A preferred configuration of the crosslinking agent is the same as that of the crosslinkable composition obtained by the production method of the present disclosure.

[0350] The crosslinkable composition may contain at least one polyfunctional compound. A polyfunctional compound is a compound having two or more functional groups of the same or different structures in one molecule. As the functional groups of the polyfunctional compound, any functional group known to generally have reactivity, such as a carbonyl group, a carboxyl group, a haloformyl group, an amide group, an olefin group, an amino group, an isocyanate group, a hydroxy group, an epoxy group, etc., can be arbitrarily used.

[0351] The crosslinkable composition can be blended with ordinary additives that are blended in the elastomer as needed, such as fillers (carbon black, barium sulfate, etc.), processing aids (waxes, etc.), plasticizers, colorants, stabilizers, tackifiers (coumarone resins, coumarone-indene resins, etc.), mold release agents, conductivity-imparting agents, heat conductivity-imparting agents, surface non-sticking agents, flexibility-imparting agents, heat resistance improvers, flame retardants, and other various additives, and one or more common crosslinking agents and crosslinking accelerators different from the above may be blended.

[0352] The content of the filler such as carbon black is not particularly limited, but it is preferably 0 to 300 parts by mass, more preferably 1 to 150 parts by mass, still more preferably 2 to 100 parts by mass, and particularly preferably 2 to 75 parts by mass with respect to 100 parts by mass of the fluorine-containing elastomer.

[0353] The content of the processing aid such as wax is preferably 0 to 10 parts by mass, more preferably 0 to 5 parts by mass with respect to 100 parts by mass of the fluorine-containing elastomer. When using a processing aid, a plasticizer or a mold release agent, the mechanical properties and sealing properties of the obtained molded product tend to decrease, so it is necessary to adjust the contents of these within the range where the characteristics of the desired molded product are acceptable.

[0354] A molded product can be obtained by crosslinking the crosslinkable composition. Also, a molded product can be obtained by molding and then crosslinking the crosslinkable composition. The crosslinkable composition can be molded by a conventionally known method. The methods and conditions of molding and crosslinking may be within the range of known methods and conditions for the molding and crosslinking to be employed. The order of molding and crosslinking is not limited, and it may be crosslinked after molding, molded after crosslinking, or molding and crosslinking may be performed simultaneously.

[0355] Examples of the molding method include, but are not limited to, compression molding, injection molding, injection molding, extrusion molding, and molding by rot cure. Examples of the crosslinking method include, but are not limited to, steam crosslinking, crosslinking by heating, radiation crosslinking, etc. Among them, steam crosslinking and crosslinking by heating are preferred. Specific crosslinking conditions that are not limited may be appropriately determined according to the types of crosslinking accelerators, crosslinking agents, acid acceptors, etc., usually within a temperature range of 140 to 250 °C and a crosslinking time of 1 minute to 24 hours.

[0356] In addition, by heating the obtained molded product with an oven or the like, mechanical properties and compression set characteristics at high temperatures can be improved. Specific crosslinking conditions that are not limited may be appropriately determined according to the types of crosslinking accelerators, crosslinking agents, acid acceptors, etc., usually within a temperature range of 140 to 300 °C and a range of 30 minutes to 72 hours.

[0357] The molded product is excellent in various properties such as heat resistance, oil resistance, chemical resistance, and flexibility, and furthermore, it is excellent in compression set characteristics at high temperatures. Therefore, the molded product is generally used in parts for the purpose of sliding in contact with other materials, sealing or encapsulating other materials or substances, vibration prevention, and sound insulation, and can be used as various parts in various fields such as the automotive industry, aircraft industry, and semiconductor industry.

[0358] Examples of the fields of use include, for example, semiconductor-related fields, automotive fields, aircraft fields, space / rocket fields, ship fields, chemical fields such as chemical plants, pharmaceutical fields such as pharmaceuticals, photographic fields such as developing machines, printing fields such as printing machines, painting fields such as painting equipment, analytical / physical and chemical machinery fields such as analytical instruments and meters, food equipment fields including food plant equipment and household goods, beverage and food manufacturing equipment fields, pharmaceutical manufacturing equipment fields, medical parts fields, chemical transportation equipment fields, nuclear power plant equipment fields, steel fields such as iron plate processing equipment, general industrial fields, electrical fields, fuel cell fields, electronic parts fields, optical equipment parts fields, space equipment parts fields, petrochemical plant equipment fields, energy resource exploration and extraction equipment parts fields for oil, gas, etc., oil refining fields, and oil transportation equipment parts fields.

[0359] Examples of the usage forms of the molded product include various sealing materials and packings such as rings, packings, gaskets, diaphragms, oil seals, bearing seals, lip seals, plunger seals, door seals, lip and face seals, gas delivery plate seals, wafer support seals, barrel seals, etc. As the sealing material, it can be used in applications where heat resistance, solvent resistance, chemical resistance, and non-stickiness are required.

[0360] Moreover, it can also be used as tubes, hoses, rolls, various rubber rolls, flexible joints, rubber plates, coatings, belts, dampers, valves, valve sheets, valve bodies of valves, chemical-resistant coating materials, laminating materials, lining materials, etc.

[0361] The cross-sectional shapes of the above-mentioned rings, packings, and seals may be of various shapes. Specifically, for example, they may be in the shapes of squares, O - shapes, heel rules, etc., or may be in irregular shapes such as D - shapes, L - shapes, T - shapes, V - shapes, X - shapes, Y - shapes, etc.

[0362] In the above semiconductor-related fields, for example, it can be used in semiconductor manufacturing equipment, liquid crystal panel manufacturing equipment, plasma panel manufacturing equipment, plasma display panel manufacturing equipment, plasma address liquid crystal panel manufacturing equipment, organic EL panel manufacturing equipment, field emission display panel manufacturing equipment, solar cell substrate manufacturing equipment, semiconductor transfer equipment, etc. Such equipment includes, for example, gas control equipment such as CVD equipment and gas control equipment for semiconductors, dry etching equipment, wet etching equipment, plasma etching equipment, reactive ion etching equipment, reactive ion beam etching equipment, sputter etching equipment, ion beam etching equipment, oxidation diffusion equipment, sputtering equipment, ashing equipment, plasma ashing equipment, cleaning equipment, ion implantation equipment, plasma CVD equipment, exhaust equipment, exposure equipment, polishing equipment, film forming equipment, dry etching cleaning equipment, UV / O3 cleaning equipment, ion beam cleaning equipment, laser beam cleaning equipment, plasma cleaning equipment, gas etching cleaning equipment, extraction cleaning equipment, Soxhlet extraction cleaning equipment, high temperature and high pressure extraction cleaning equipment, microwave extraction cleaning equipment, supercritical extraction cleaning equipment, cleaning equipment using hydrofluoric acid, hydrochloric acid, sulfuric acid, ozone water, etc., steppers, coater-developers, CMP equipment, excimer laser exposure machines, chemical liquid pipes, gas pipes, equipment for performing plasma treatments such as NF3 plasma treatment, O2 plasma treatment, and fluorine plasma treatment, heat treatment film forming equipment, wafer transfer equipment, wafer cleaning equipment, silicon wafer cleaning equipment, silicon wafer processing equipment, equipment used in the LP-CVD process, equipment used in the lamp annealing process, equipment used in the reflow process, and the like.

[0363] As specific usage forms in the semiconductor-related fields, for example, various sealing materials such as O-rings and gaskets for gate valves, quartz windows, chambers, chamber lids, gates, bell jars, couplings, and pumps; various sealing materials such as O-rings for resist developers and strippers, hoses and tubes; linings and coatings for resist developer tanks, stripper tanks, wafer cleaning liquid tanks, and wet etching tanks; diaphragms of pumps; rolls for wafer transfer; hose tubes for wafer cleaning liquid; sealing materials for clean facilities such as clean rooms; sealing materials for storage vaults for storing semiconductor manufacturing equipment and devices such as wafers; and diaphragms for chemical liquid transfer used in the process of manufacturing semiconductors, etc. can be mentioned.

[0364] In the above automotive fields, it can be used for engine blocks, main motion systems, valve systems, lubrication and cooling systems, fuel systems, intake and exhaust systems, transmission systems of drive systems, steering systems of chassis, brake systems, and electrical components such as basic electrical components, control system electrical components, and equipment electrical components. Note that the above automotive fields include motorcycles.

[0365] In the engine block and its peripheral devices as described above, molded products can be used for various sealing materials that require heat resistance, oil resistance, fuel oil resistance, engine coolant antifreeze resistance, and steam resistance. Such sealing materials include, for example, seals such as gaskets, shaft seals, and valve stem seals, and non-contact or contact-type packings such as self-sealing packings, piston rings, split-ring packings, mechanical seals, and oil seals, bellows, diaphragms, hoses, tubes, as well as wires, cushioning materials, vibration-proof materials, and various sealing materials used in belt AT devices, etc.

[0366] As specific usage forms in the above fuel system, O-rings used in fuel injectors, cold start injectors, quick connectors of fuel lines, sender flange quick connectors, fuel pumps, fuel tank quick connectors, gasoline mixing pumps, gasoline pumps, tube bodies of fuel tubes, connectors of fuel tubes, injectors, etc.; seals used in exhaust system manifolds, fuel filters, pressure regulating valves, canisters, caps of fuel tanks, fuel pumps, fuel tanks, sender units of fuel tanks, fuel injection devices, fuel high-pressure pumps, fuel line connector systems, pump timing control valves, suction control valves, solenoid sub-assemblies, fuel cut-off valves, etc.; seals such as canister purge solenoid valve seals, on-board refueling vapor recovery (ORVR) valve seals, oil seals for fuel pumps, fuel sender seals, fuel tank roll-over valve seals, filler seals, injector seals, filler cap seals, seals of filler cap valves; hoses such as fuel hoses, fuel supply hoses, fuel return hoses, vapor (evap) hoses, vent (breather) hoses, filler hoses, filler neck hoses, hoses inside fuel tanks (intank hoses), control hoses of carburetors, fuel inlet hoses, fuel breather hoses, etc.; gaskets used in fuel filters, fuel line connector systems, etc., and flange gaskets used in carburetors, etc.; line materials such as vapor recovery lines, fuel feed lines, vapor ORVR lines, etc.; diaphragms used in canisters, ORVR, fuel pumps, fuel tank pressure sensors, gasoline pumps, sensors of carburetors, composite air control devices (CAC), pulsation dampers, for canisters, auto cocks, etc., and pressure regulator diaphragms of fuel injection devices; valves for fuel pumps, carburetor needle valves, roll-over check valves, check valves; vents (breather), tubes used inside fuel tanks; tank packings such as for fuel tanks, packings of acceleration pump pistons of carburetors; fuel sender vibration-proof parts for fuel tanks;O-rings, diaphragms for controlling fuel pressure, accelerator pump cups, in-tank fuel pump mounts, injector cushion rings of fuel injection devices, injector seal rings, needle valve core valves of carburetors, accelerator pump pistons of carburetors, valve seats of composite air control devices (CACs), fuel tank bodies, seal parts for solenoid valves, etc.

[0367] Specific usage forms in the above braking system include diaphragms used in master backs, hydraulic brake hoses, air brakes, brake chambers of air brakes, etc.; hoses used in brake hoses, brake oil hoses, vacuum brake hoses, etc.; various sealing materials such as oil seals, O-rings, packings, brake piston seals, etc.; atmosphere valves and vacuum valves for master backs, check valves for brake valves; piston cups (rubber cups) for master cylinders, brake cups; boots for master cylinders of hydraulic brakes, vacuum boosters, wheel cylinders of hydraulic brakes, O-rings and grommets for antilock brake systems (ABS), etc.

[0368] Specific usage forms in the above basic electrical components include insulators and sheaths of electric wires (harnesses), tubes of harness exterior components, grommets for connectors, etc.

[0369] Specific usage forms in control system electrical components include coating materials for various sensor wires, etc.

[0370] Specific usage forms in the above equipment electrical components include O-rings, packings of car air conditioners, cooler hoses, high-pressure air conditioner hoses, air conditioner hoses, gaskets for electronic throttle units, plug boots for direct ignition, diaphragms for distributors, etc. Also, it can be used for the adhesion of electrical components.

[0371] As specific usage forms in the above intake and exhaust systems, there are packings used in intake manifolds, exhaust manifolds, etc., throttle body packings for throttles; diaphragms used in EGR (exhaust gas recirculation), boost control (BPT), wastegates, turbo wastegates, actuators, actuators for variable turbine geometry (VTG) turbos, exhaust purification valves, etc.; control hoses for EGR (exhaust gas recirculation), emission control hoses, turbocharger turbo oil hoses (supply), turbo oil hoses (return), turbo air hoses, intercooler hoses, turbocharger hoses, hoses connected to the compressor of a turbo engine equipped with an intercooler, exhaust gas hoses, air intake hoses, turbo hoses, DPF (diesel particulate filter) sensor hoses, etc.; air ducts and turbo air ducts; intake manifold gaskets; sealing materials for EGR, afterburn prevention valve sheets for AB valves, turbine shaft seals (such as for turbochargers), and sealing members used for groove parts such as rocker covers and air intake manifolds used in automobile engines, etc.

[0372] In addition, in exhaust gas control parts, seals used in vapor recovery canisters, catalytic converters, exhaust gas sensors, oxygen sensors, etc., and seals for solenoid armatures of vapor recovery and vapor canisters can be used as intake system manifold gaskets, etc.

[0373] Also, in parts related to diesel engines, it can be used as O-ring seals for direct injection injectors, rotary pump seals, control diaphragms, fuel hoses, EGR, priming pumps, diaphragms for boost compensators, etc. It can also be used in O-rings, sealing materials, hoses, tubes, diaphragms, gasket materials, pipes used in urea SCR systems, the urea water tank body of the urea SCR system, and the sealing material of the urea water tank.

[0374] Specific usage forms in the above transmission system include bearing seals related to the transmission, oil seals, O-rings, packings, Turkcon hoses, etc. Also included are mission oil seals, mission oil hoses for AT, ATF hoses, O-rings, packings, etc.

[0375] Note that transmissions include AT (Automatic Transmission), MT (Manual Transmission), CVT (Continuously Variable Transmission), DCT (Dual Clutch Transmission), etc.

[0376] In addition, oil seals, gaskets, O-rings, packings for manual or automatic transmissions, and oil seals, gaskets, O-rings, packings for continuously variable transmissions (belt type or toroidal type). Also included are packings for ATF linear solenoids, oil hoses for manual transmissions, ATF hoses for automatic transmissions, CVTF hoses for continuously variable transmissions (belt type or toroidal type), etc.

[0377] Specific usage forms in the steering system include power steering oil hoses, high-pressure power steering hoses, etc.

[0378] Forms used in the engine body of an automotive engine include, for example, gaskets such as cylinder head gaskets, cylinder head cover gaskets, oil pan packings, general gaskets, O-rings, packings, seals such as timing belt cover gaskets, hoses such as control hoses, vibration-damping rubber for engine mounts, control valve diaphragms, camshaft oil seals, etc.

[0379] In the main motion system of an automotive engine, it can be used for shaft seals such as crankshaft seals and camshaft seals.

[0380] In the valve train of an automotive engine, it can be used for valve stem oil seals of engine valves, valve seats of butterfly valves, etc.

[0381] In the lubrication and cooling system of an automotive engine, it can be used for engine oil cooler hoses of engine oil coolers, oil return hoses, seal gaskets, water hoses around radiators, seals of radiators, gaskets of radiators, O-rings of radiators, vacuum pump oil hoses of vacuum pumps, etc. In addition, it can be used for radiator hoses, radiator tanks, diaphragms for oil pressure, fan coupling seals, etc.

[0382] Thus, as an example of specific examples of use in the automotive field, engine head gaskets, oil pan gaskets, manifold packings, seals for oxygen sensors, oxygen sensor bushes, seals for nitrogen oxide (NO x ) sensors, seals for nitrogen oxide (NO x)Sensor bush, seal for sulfur oxide sensor, seal for temperature sensor, temperature sensor bush, seal for diesel particulate filter sensor, diesel particulate filter sensor bush, injector O-ring, injector packing, O-ring and diaphragm of fuel pump, gearbox seal, power piston packing, seal of cylinder liner, seal of valve stem, static valve stem seal, dynamic valve stem seal, front pump seal of automatic transmission, rear axle pinion seal, gasket of universal joint, pinion seal of speedometer, piston cup of foot brake, O-ring and oil seal of torque transmission device, seal and bearing seal of exhaust gas reburning device, hose for reburning device, diaphragm for sensor of carburetor, vibration damping rubber (engine mount, exhaust part, muffler hanger, suspension bush, center bearing, strut bumper rubber, etc.), vibration damping rubber for suspension (strut mount, bush, etc.), vibration damping rubber for drive system (damper, etc.), fuel hose, tube and hose for EGR, twin carburetor tube, core valve of needle valve of carburetor, flange gasket of carburetor, oil hose, oil cooler hose, ATF hose, cylinder head gasket, water pump seal, gearbox seal, needle valve tip, lead of lead valve for motorcycle, oil seal of automobile engine, seal of gasoline hose gun, seal for car air conditioner, rubber hose for engine intercooler, fuel line connector deviceSeals for systems , CAC valves, needle tips, engine wiring harnesses, filler hoses, automotive air conditioner O-rings, intake gaskets, fuel tank materials, diaphragms for distributors, water hoses, clutch hoses, PS hoses, AT hoses, master brake hoses, heater hoses, air conditioner hoses, ventilation hoses, oil filler caps, PS rack seals, rack & pinion boots, CVJ boots, ball joint dust covers, strut dust covers, weatherstrips, glass runs, center unit packings, body site welts, bumper rubbers, door latches, dash insulators, high tension cords, flat belts, poly V belts, timing belts, toothed belts, V ribbed belts, tires, wiper blades, diaphragms and plungers for LPG vehicle regulators, diaphragms and valves for CNG vehicle regulators, DME compatible rubber parts, diaphragms and boots for auto tensioners, diaphragms and valves for idle speed controls, actuators for auto speed controls, diaphragms, check valves and plungers for vacuum pumps, diaphragms and O-rings for O.P.S., gasoline pressure relief valves, O-rings and gaskets for engine cylinder sleeves, O-rings and gaskets for wet cylinder sleeves, seals and gaskets for differential gears (seals and gaskets for gear oil), seals and gaskets for power steering devices (seals and gaskets for PSF), seals and gaskets for shock absorbers (seals and gaskets for SAF), seals and gaskets for constant velocity joints, seals and gaskets for wheel bearings, coating agents for metal gaskets, caliper seals, boots, wheel bearing seals, bladders used for vulcanizing and molding tires, etc.

[0383] In the above aircraft field, space / rocket field, and ship field, it can be particularly used in fuel systems and lubricating oil systems.

[0384] In the above-mentioned aircraft field, for example, it can be used as various sealing parts for aircraft, various parts for aircraft engine oil applications in aircraft, jet engine valve stem seals, gaskets, O-rings, rotating shaft seals, gaskets for hydraulic equipment, firewall seals, fuel supply hoses, gaskets, O-rings, aircraft cables, oil seals, shaft seals, etc.

[0385] In the above-mentioned space and rocket fields, for example, it can be used as lip seals, diaphragms, O-rings for spacecraft, jet engines, missiles, etc., O-rings for oil resistant to gas turbine engines, vibration isolation pad for missile ground control, etc.

[0386] Also, in the ship field, for example, it can be used as a propeller shaft stern seal for a screw, a valve stem seal for intake and exhaust of a diesel engine, a valve seal for a butterfly valve, a valve seat and shaft seal for a butterfly valve, a shaft seal for a butterfly valve, a stern tube seal, a fuel hose, a gasket, an O-ring for an engine, a ship cable, a ship oil seal, a ship shaft seal, etc.

[0387] In the chemical fields such as the above-mentioned chemical plants and the pharmaceutical fields such as pharmaceuticals, it can be used in processes that require high chemical resistance, for example, in the processes of manufacturing chemicals such as pharmaceuticals, agricultural chemicals, paints, resins, etc.

[0388] Specific usage forms in the above chemical and pharmaceutical fields include seals used in chemical apparatuses, pumps and flow meters for chemical agents, piping for chemical agents, heat exchangers, pesticide sprayers, pesticide transfer pumps, gas piping, fuel cells, analytical instruments and physicochemical instruments (for example, columns and fittings of analytical instruments and measuring instruments, etc.), contraction joints of flue gas desulfurization devices, nitric acid plants, power plant turbines, etc., seals used in medical sterilization processes, seals for plating solutions, colloseals for paper-making belts, joint seals of wind tunnels; O-rings used in chemical apparatuses such as reactors and agitators, analytical instruments and measuring instruments, chemical pumps, pump housings, valves, rotameters, etc., O-rings for mechanical seals, O-rings for compressor seals; packings used in high-temperature vacuum dryers, tube joints of gas chromatography and pH meters, etc., glass cooler packings of sulfuric acid production devices; diaphragms used in diaphragm pumps, analytical instruments and physicochemical instruments, etc.; gaskets used in analytical instruments and measuring instruments; ferrules used in analytical instruments and measuring instruments; valve seats; U-cups; linings used in chemical apparatuses, gasoline tanks, wind tunnels, etc., corrosion-resistant linings of anodizing tanks; coatings of masking jigs for plating; valve parts of analytical instruments and physicochemical instruments; expansion joints of flue gas desulfurization plants; acid-resistant hoses for concentrated sulfuric acid, etc., chlorine gas transfer hoses, oil-resistant hoses, rainwater drain hoses for benzene and toluene storage tanks; chemical-resistant tubes and medical tubes used in analytical instruments and physicochemical instruments, etc.; rolls resistant to trichlene for fiber dyeing and dyeing rolls; stoppers of pharmaceuticals; rubber stoppers for medical use; chemical solution bottles, chemical solution tanks, bags, chemical containers; protective gear such as gloves and boots resistant to strong acids and solvents, etc.

[0389] In the photographic field such as the above-described developing machines, the printing field such as printing machines, and the painting field such as painting equipment, it can be used as rolls, belts, seals, valve parts, etc. of dry photocopiers.

[0390] Specific usage forms in the above-mentioned photographic field, printing field, and painting field include the surface layer of the transfer roll of a copying machine, the cleaning blade of a copying machine, the belt of a copying machine; rolls for OA equipment such as copying machines, printers, and facsimiles (for example, fixing rolls, pressure rolls, pressing rolls, etc.), belts; rolls of PPC copying machines, roll blades, belts; rolls of film developing machines, X-ray film developing machines; printing rolls, scrapers, tubes, valve parts, belts of printing machines; ink tubes, rolls, belts of printers; coating rolls, scrapers, tubes, valve parts of coating and painting equipment; developing rolls, gravure rolls, guide rolls, guide rolls of magnetic tape manufacturing coating lines, gravure rolls of magnetic tape manufacturing coating lines, coating rolls, etc.

[0391] In the food equipment field including the above-mentioned food plant equipment and household items, it can be used in food manufacturing processes and for food conveyors or food storage devices.

[0392] Specific usage forms in the above-mentioned food equipment field include seals of plate heat exchangers, solenoid valve seals of vending machines, packings of jar pots, sanitary pipe packings, packings of pressure cookers, seals of water heaters, gaskets for heat exchangers, diaphragms and packings for food processing and treatment devices, rubber materials for food processing and treatment machines (for example, various seals such as heat exchanger gaskets, diaphragms, O-rings, pipes, hoses, sanitary packings, valve packings, filling packings used as joints between the mouths of bottles and fillers during filling), etc. Also, packings, gaskets, tubes, diaphragms, hoses, joint sleeves, etc. used in products such as alcoholic beverages and soft drinks, filling devices, food sterilization devices, brewing devices, water heaters, various automatic food vending machines, etc. are also included.

[0393] In the above-mentioned nuclear power plant equipment field, it can be used for check valves and pressure reducing valves around nuclear reactors, seals of uranium hexafluoride enrichment devices, etc.

[0394] Specific usage forms in the above general industrial fields include sealing materials for hydraulic equipment such as machine tools, construction machinery, and hydraulic machinery; seals for hydraulic and lubrication machinery and bearing seals; sealing materials used for mandrels, etc.; seals used for windows of dry cleaning equipment, etc.; seals for cyclotrons and (vacuum) valve seals, seals for proton accelerators, seals for automatic packaging machines, diaphragms for pumps of sulfurous acid gas and chlorine gas analyzers (pollution measuring instruments) in the air, snake pump linings, rolls and belts of printing machines, conveying belts (conveyor belts), squeezing rolls for pickling iron plates, etc., cables of robots, solvent squeezing rolls for aluminum rolling lines, O-rings of couplings, acid-resistant cushioning materials, dust seals and lip rubbers for sliding parts of machining machines, gaskets for waste incineration treatment machines, friction materials, surface modifiers for metals or rubbers, coating materials, etc. Also, it can be used as gaskets and sealing materials for devices used in the papermaking process, sealing agents for filter units in clean rooms, building sealing agents, protective coating agents for concrete, cement, etc., glass cloth impregnating materials, processing aids for polyolefins, additives for improving the moldability of polyethylene, fuel containers for small generators, lawn mowers, etc., pre-coated metals obtained by subjecting metal plates to primer treatment, etc. In addition, it can also be impregnated into woven fabrics, baked, and used as sheets and belts.

[0395] Specific usage forms in the above steel field include iron plate processing rolls of iron plate processing equipment, etc.

[0396] As specific usage forms in the above electrical field, there are insulating oil caps for bullet trains, venting seals for liquid-sealed transformers, seals for transformers, jackets for oil well cables, seals for ovens such as electric furnaces, window frame seals for microwave ovens, sealants used when adhering the wedge and neck of a CRT, sealants for halogen lamps, fixing agents for electrical components, sealants for end treatment of heat-seeking heaters, sealants used for insulating and moisture-proof treatment of electrical equipment lead wire terminals, and the like. Further, it can also be used as a coating material for oil-resistant and heat-resistant electric wires, high heat-resistant electric wires, chemical-resistant electric wires, high-insulation electric wires, high-voltage transmission lines, cables, electric wires used in geothermal power generation devices, electric wires used around automobile engines, and the like. It can also be used for oil seals and shaft seals of vehicle cables. Furthermore, it can also be used for electrical insulation materials (for example, insulating spacers for various electrical equipment, insulating tapes used for joints and ends of cables, materials used for heat-shrinkable tubes, etc.) and electrical and electronic equipment materials used in high-temperature atmospheres (for example, outlet wire materials for motors, wire materials around high-temperature furnaces). It can also be used for the sealing layer and protective film (backsheet) of solar cells.

[0397] In the above fuel cell field, it can be used as a sealant between electrodes, between electrodes and separators, seals and packings for pipes such as hydrogen, oxygen, and generated water, and separators in polymer electrolyte fuel cells, phosphate fuel cells, and the like.

[0398] In the field of the above electronic components, it can be used for raw materials of heat dissipation materials, raw materials of electromagnetic shielding materials, gaskets for computer hard disk drives (magnetic recording devices), etc. Also, buffer rubbers (crash stoppers) of hard disk drives, binders for electrode active materials of nickel-metal hydride secondary batteries, binders for active materials of lithium-ion batteries, polymer electrolytes of lithium secondary batteries, binders for positive electrodes of alkaline storage batteries, binders for EL elements (electroluminescence elements), binders for electrode active materials of capacitors, encapsulants, sealing agents, coating materials for quartz of optical fibers, films and sheets such as optical fiber coating materials, electronic components such as CMOS electronic circuits, transistors, integrated circuits, organic transistors, light-emitting elements, actuators, memories, sensors, coils, capacitors, resistors, potting, coating, and adhesive seals for circuit boards, fixing agents for electronic components, modifiers for encapsulants such as epoxy, coating agents for printed circuit boards, modifiers for printed wiring board prepreg resins such as epoxy, scattering prevention materials for electric bulbs, gaskets for computers, large computer cooling hoses, secondary batteries, especially gaskets and packings such as O-rings for lithium secondary batteries, sealing layers covering one or both sides of the outer surface of organic EL structures, connectors, dampers, etc.

[0399] In the field of the above equipment for transporting chemical drugs, it can be used for safety valves, discharge valves, etc. of trucks, trailers, tank lorries, ships, etc.

[0400] In the field of parts of equipment for exploring and mining energy resources such as petroleum and gas, it is used as various sealing materials used in the mining of petroleum, natural gas, etc., boots of electrical connectors used in oil wells, etc.

[0401] Specific usage forms in the field of the above energy resource exploration and mining equipment parts include drill bit seals, pressure regulating diaphragms, seals for horizontal excavation motors (stators), stator bearing (shaft) seals, sealing materials used in blowout preventers (BOPs), sealing materials used in rotary blowout preventers (pipe wipers), sealing materials used in MWD (real-time drilling information detection systems) and gas-liquid connectors, logging tool seals (such as O-rings, seals, packings, gas-liquid connectors, boots, etc.) used in logging equipment, expansion packers and compression packers and the packer seals used for them, seals and packings used in cementing devices, seals used in perforators (drilling devices), seals, packings and motor linings used in mud pumps, underground listening detector covers, U-cups, composite seating cups, rotary seals, laminated elastomeric bearings, seals for flow control, seals for sand volume control, seals for safety valves, seals for hydraulic fracturing equipment, seals and packings for linear packers and linear hangers, seals and packings for wellheads, seals and packings for chokes and valves, sealing materials for LWD (logging while drilling), diaphragms used in oil exploration and oil drilling applications (such as lubricating oil supply diaphragms for oil drilling pits, etc.), gate valves, electronic boots, seal elements for perforating guns, etc.

[0402] In addition, it can also be used for joint seals in kitchens, bathrooms, washrooms, etc.; tent tarps outdoors; seals for printing materials; rubber hoses for gas heat pumps, CFC-resistant rubber hoses; agricultural films, linings, weather-resistant covers; tanks such as laminated steel plates used in the fields of construction and household appliances, etc.

[0403] Furthermore, it is also possible to use it as an article combined with metals such as aluminum. Such usage forms include, for example, door seals, gate valves, pendulum valves, solenoid tips, as well as piston seals and diaphragms combined with metals, metal rubber parts combined with metals such as metal gaskets, etc.

[0404] In addition, it can also be used for rubber parts, brake shoes, brake pads, etc. in bicycles.

[0405] In addition, the molded product can be applied to a belt.

[0406] Examples of the belt include the following. Power transmission belts (including flat belts, V-belts, V-ribbed belts, toothed belts, etc.), conveyor belts (conveyor belts) such as flat belts used in various high-temperature parts around the engines of agricultural machinery, machine tools, industrial machinery, etc.; conveyor belts for transporting bulk materials and granular materials such as coal, crushed stone, earth and sand, ore, wood chips, etc. in a high-temperature environment; conveyor belts used in ironworks such as blast furnaces; conveyor belts for applications exposed to high-temperature environments in precision equipment assembly factories, food factories, etc.; V-belts and V-ribbed belts for agricultural machinery, general equipment (e.g., OA equipment, printing machinery, industrial dryers, etc.), automobiles, etc.; transmission belts of conveying robots; toothed belts such as transmission belts of food machinery and machine tools; toothed belts used in automobiles, OA equipment, medical equipment, printing machinery, etc.

[0407] In particular, as the toothed belt for automobiles, the timing belt is typical.

[0408] The above belt may have a single-layer structure or a multi-layer structure.

[0409] In the case of a multi-layer structure, the above belt may be composed of a layer obtained by cross-linking a cross-linkable composition and a layer made of other materials.

[0410] In the multi-layer structure belt, examples of the layer made of other materials include layers made of other rubbers, layers made of thermoplastic resins, various fiber reinforcing layers, canvas, metal foil layers, etc.

[0411] The molded product can also be used for industrial vibration isolation pads, vibration isolation mats, railway slab mats, pads, automotive vibration isolation rubbers, etc. Examples of automotive vibration isolation rubbers include vibration isolation rubbers for engine mounts, motor mounts, member mounts, strut mounts, bushings, dampers, muffler hangers, center bearings, etc.

[0412] As other usage forms, joint members such as flexible joints and expansion joints, boots, grommets, etc. can be mentioned. In the marine field, for example, marine pumps, etc. can be mentioned.

[0413] A joint member refers to a joint used for pipes and piping facilities, and is used for applications such as preventing vibration and noise generated from the piping system, absorbing expansion, contraction, and displacement due to temperature changes and pressure changes, absorbing dimensional variations, and mitigating and preventing the effects of earthquakes and ground subsidence.

[0414] Flexible joints and expansion joints can be preferably used, for example, as complex-shaped molded bodies for shipbuilding pipes, machine pipes such as pumps and compressors, chemical plant pipes, electrical pipes, civil engineering and water supply pipes, automotive uses, etc. Boots can be preferably used, for example, as complex-shaped molded bodies such as automotive boots such as constant velocity joint boots, dust covers, rack and pinion steering boots, pin boots, piston boots, agricultural machinery boots, industrial vehicle boots, construction machinery boots, hydraulic machinery boots, pneumatic machinery boots, centralized lubrication machine boots, liquid transfer boots, fire boots, various industrial boots for transferring various liquefied gases, etc.

[0415] The molded product can also be used for diaphragms for filter presses, blowers, water supply, liquid storage tanks, pressure switches, accumulators, diaphragms for air springs such as suspensions, etc.

[0416] By adding the molded article to rubber or resin, an anti-slip agent can be obtained that yields a molded article or a coating film that is difficult to slip in an environment wetted by water such as rain, snow, ice, or sweat.

[0417] In addition, the molded article can also be used, for example, as a cushioning material for hot press molding when manufacturing decorative plywood, printed circuit boards, electrical insulation boards, rigid polyvinyl chloride laminated boards, etc. made of melamine resin, phenolic resin, epoxy resin, etc.

[0418] The molded article can also contribute to the impermeability of various supports such as sealing gaskets related to weapons and protective clothing against contact with invasive chemical agents.

[0419] In addition, it can be used for O (angle)-rings, V-rings, X-rings, packings, gaskets, diaphragms, oil seals, bearing seals, lip seals, plunger seals, door seals, lips and face seals, gas delivery plate seals, wafer support seals, barrel seals, and other various sealing materials used to seal lubricating oils (engine oils, transmission oils, gear oils, etc.), fuel oils, and greases (especially urea-based greases) containing amine-based additives (especially amine-based additives used as antioxidants and detergent dispersants) used in transportation equipment such as automobiles and ships. It can also be used as tubes, hoses, various rubber rolls, coatings, belts, valve bodies of valves, etc. It can also be used as a material for lamination and lining.

[0420] It can also be used as a coating material for heat-resistant and oil-resistant electric wires used for lead wires of sensors that come into contact with transmission oil and / or engine oil of internal combustion engines in automobiles, etc. and detect the oil temperature and / or oil pressure, and can also be used in a high-temperature oil atmosphere such as inside the oil pan of an automatic transmission or an engine.

[0421] In addition, there are cases where a vulcanized film is formed on the molded product for use. Specifically, examples include non-stick oil-resistant rolls for copiers, weather strips for preventing weathering and icing, rubber stoppers for transfusion, vial rubber stoppers, release agents, non-stick light-conveying belts, anti-adhesion films for pre-gas gaskets of automotive engine mounts, coating processes for synthetic fibers, bolt members or joints with a thin packing coating layer, and the like.

[0422] Regarding the use of molded products for automotive-related parts, parts for motorcycles with the same structure are also included.

[0423] Also, examples of fuels in the above automotive-related applications include light oil, gasoline, fuels for diesel engines (including biodiesel fuel), and the like.

[0424] The molded product can also be used for seal members for rolling bearings.

[0425] Examples of the above rolling bearings include ball bearings, roller bearings, bearing units, linear bearings, and the like.

[0426] Examples of ball bearings include radial ball bearings, thrust ball bearings, thrust angular ball bearings, and the like.

[0427] Examples of the above radial ball bearings include deep groove ball bearings, angular ball bearings, four-point contact ball bearings, self-aligning ball bearings, and the like.

[0428] The above deep groove ball bearings are used, for example, in electric motors, household electrical appliances, OA equipment, and the like.

[0429] Examples of the angular ball bearings include single-row angular ball bearings, combined angular ball bearings, double-row angular ball bearings, etc. Single-row angular ball bearings are used in electric motors, household electrical appliances, OA equipment, etc., as well as in hydraulic pumps, vertical pumps, etc. that are subject to axial loads in addition to radial loads. Combined angular ball bearings are used in the main shafts of machine tools, grinding spindles, etc. where improved rotational accuracy of the shaft and increased rigidity are required. Double-row angular ball bearings are used in electromagnetic clutches for automotive air conditioners, etc.

[0430] The above four-point contact ball bearing is subject to axial loads from both directions and is used in reducers, etc. where the space for the bearing width cannot be made large.

[0431] The above self-aligning ball bearing is used in locations where it is difficult to align the shaft and the housing, or in transmission shafts where the shaft is easily deflected, etc.

[0432] Examples of the thrust ball bearings include single-thrust ball bearings and double-thrust ball bearings, and these ball bearings are applicable to conventionally known uses where they are used.

[0433] The above thrust angular ball bearing is used in combination with a double-row cylindrical roller bearing as an axial load receiver for the main shaft of a machine tool.

[0434] Examples of the roller bearings include radial roller bearings, thrust roller bearings, etc.

[0435] Examples of the above radial roller bearings include cylindrical roller bearings, needle roller bearings, tapered roller bearings, and self-aligning roller bearings.

[0436] The above cylindrical roller bearings are used in general machinery, machine tools, electric motors, reducers, railway axles, aircraft, etc.

[0437] Needle roller bearings are used in general machinery, automobiles, electric motors, etc.

[0438] Tapered roller bearings are used in machine tools, automotive and railway axles, rolling mills, reducers, etc.

[0439] The self-aligning roller bearing is used in general machinery, rolling mills, paper-making machines, axles, etc.

[0440] Examples of the thrust roller bearing include a thrust cylindrical roller bearing, a thrust needle roller bearing, a thrust tapered roller bearing, a thrust self-aligning roller bearing, etc.

[0441] The thrust cylindrical roller bearing is used in machine tools, general machinery, etc.

[0442] The thrust needle roller bearing is used in automobiles, pumps, general machinery, etc.

[0443] The thrust tapered roller bearing is used in general machinery, rolling mills, etc.

[0444] The thrust self-aligning roller bearing is used in cranes, extruders, general machinery, etc.

[0445] In addition to being crosslinked and used as a molded product, the crosslinkable composition can also be used as various parts in various industrial fields. Therefore, next, the uses of the crosslinkable composition will be described.

[0446] The crosslinkable composition can be used as a surface modifier for metals, rubbers, plastics, glass, etc.; seal materials and coating materials such as metal gaskets and oil seals that require heat resistance, chemical resistance, oil resistance, and non-stick properties; non-stick coating materials such as rolls for OA equipment and belts for OA equipment, or bleed barriers; impregnation of woven fabric sheets and belts, and coating by baking, etc.

[0447] By making the crosslinkable composition have a high viscosity and high concentration, it can be used as a seal material, lining, and sealant with a complex shape by the normal usage method. By making it have a low viscosity, it can be used for forming a thin film with a thickness of several microns. By making it have a medium viscosity, it can be used for coating pre-coated metals, O-rings, diaphragms, and lead valves.

[0448] Furthermore, it can also be used for coating applications such as conveying rolls or belts for woven fabrics and paper sheets, printing belts, chemical-resistant tubes, stoppers, and Huehl hoses.

[0449] As the article substrate to be coated with the crosslinkable composition, metals such as iron, stainless steel, copper, aluminum, and brass; glass products such as glass plates, woven and non-woven fabrics of glass fibers; molded products and coatings of general-purpose and heat-resistant resins such as polypropylene, polyoxymethylene, polyimide, polyamideimide, polysulfone, polyethersulfone, and polyetheretherketone; molded products and coatings of general-purpose rubbers such as SBR, butyl rubber, NBR, and EPDM, and heat-resistant rubbers such as silicone rubber and fluororubber; woven and non-woven fabrics of natural and synthetic fibers; etc. can be used.

[0450] The coating formed from the crosslinkable composition can be used in fields where heat resistance, solvent resistance, lubricity, and non-stick properties are required. Specific applications include rolls (e.g., fusing rolls, pressure rolls) and conveying belts for OA equipment such as copiers, printers, and facsimiles; sheets and belts; O-rings, diaphragms, chemical-resistant tubes, fuel hoses, valve seals, gaskets for chemical plants, engine gaskets, etc.

[0451] The crosslinkable composition can also be dissolved in a solvent and used as a paint or an adhesive. It can also be used as a paint in the form of an emulsion dispersion (latex).

[0452] The crosslinkable composition is used as a sealing material, lining, surface treatment agent, etc. for various devices, pipes, etc., and for structures made of inorganic and organic substrates such as metals, ceramics, glass, stone, concrete, plastics, rubber, wood, paper, and fibers.

[0453] The crosslinkable composition can be applied to substrates, etc. by dispenser method coating or screen printing coating.

[0454] The crosslinkable composition may be used as a coating composition for casting a film or for dipping a substrate such as fabric, plastic, metal, or elastomer.

[0455] In particular, the crosslinkable composition may be used in the form of a latex for coated fabrics, protective gloves, impregnated fibers, O-ring coatings, coatings for fuel system quick connect O-rings, coatings for fuel system seals, coatings for fuel tank rollover valve diaphragms, coatings for fuel tank pressure sensor diaphragms, coatings for oil filters and fuel filter seals, coatings for fuel tank sender seals and sender head fitting seals, coatings for copier fuser mechanism rolls, and for producing polymer coating compositions.

[0456] They are useful for coating silicone rubber, nitrile rubber, and other elastomers. For the purpose of enhancing both the heat stability and the permeation resistance and chemical resistance of the substrate elastomer, they are also useful for coating parts made from such elastomers. Other applications include coatings for heat exchangers, expansion joints, baths, tanks, fans, flue ducts and other conduits, and storage structures, such as concrete storage structures. The crosslinkable composition may be applied to the exposed cross-section of a multi-layer component structure, for example in the production of hose structures and diaphragms. Sealing members at connections and joints are often made from hard materials, and the crosslinkable composition provides enhanced dimensional interference fit with a reduced amount of leakage along the improved frictional interface and sealing surface. The latex enhances seal durability in various automotive system applications.

[0457] They can also be used in the manufacture of power steering systems, fuel systems, air conditioning systems, and any joints where hoses and tubes are connected to other components. A further utility of the crosslinkable composition is in the repair of manufacturing defects (and damage resulting from use) in multi-layer rubber structures such as three-layer fuel hoses. The crosslinkable composition can be formed or embossed before or after the paint is applied and is also useful for coating thin steel sheets. For example, multiple layers of coated steel can be assembled to create a gasket between two rigid metal members. The sealing effect is obtained by applying a crosslinkable composition between the layers. This process can be used to manufacture engine head gaskets and exhaust manifold gaskets in order to reduce the bolt force and strain of assembled parts, while providing good fuel economy and low emissions due to low cracking, deflection, and hole distortion.

[0458] The crosslinkable composition can also be used as other coating agents; substrate-integrated gaskets, packings, etc. formed by dispenser molding on substrates containing inorganic materials such as metals and ceramics; multi-layer products formed by coating substrates containing inorganic materials such as metals and ceramics.

[0459] The crosslinkable composition is also suitable as a wiring material for lightweight and bendable electronic devices and can be used in known electronic components. Examples of electronic components include CMOS electronic circuits, transistors, integrated circuits, organic transistors, light-emitting elements, actuators, memories, sensors, coils, capacitors, resistors, etc. By using this, flexible electronic devices such as solar cells, various displays, sensors, actuators, electronic artificial skin, sheet scanners, braille displays, and wireless power transmission sheets can be obtained.

[0460] Although the embodiments have been described above, it will be understood that various changes in form and detail are possible without departing from the spirit and scope of the claims.

Examples

[0461] Next, embodiments of the present disclosure will be described with examples, but the present disclosure is not limited to such examples.

[0462] Each numerical value in the examples was measured by the following method.

[0463] <Oxygen concentration in the reactor> Regarding the gas discharged from the exhaust gas line connected to the reactor, the oxygen concentration in the reactor during polymerization was determined by measuring and analyzing the gas using a low-concentration oxygen analyzer (trade name "PS-820-L", manufactured by Iijima Electronics Industry Co., Ltd.).

[0464] <Concentration of polymer> Approximately 1 g of an aqueous solution of the polymer was dried in a vacuum dryer at 60 °C for 60 minutes, the mass of the heat residue was measured, and the value obtained by expressing the ratio of the mass of the heat residue to the mass of the aqueous polymer solution (1 g) as a percentage was adopted.

[0465] <Weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the polymer> By gel permeation chromatography (GPC), using 1260 Infinity II manufactured by Agilent Technologies, and using a column (TSKgel G3000PW XL (one) manufactured by Tosoh Corporation, a mixed solvent of tris buffer and acetonitrile (tris buffer: acetonitrile = 8:2 (v / v)) was used as the solvent and flowed at a flow rate of 0.5 ml / min for measurement, and the molecular weight was calculated using monodisperse polyethylene oxide (PEO) and polyethylene glycol (PEG) as standards.

[0466] <Solid content concentration of the aqueous dispersion containing the fluorine-containing elastomer> 1 g of the aqueous dispersion containing the fluorine-containing elastomer was dried in a blower dryer at 150 °C for 180 minutes, the mass of the heat residue was measured, and the ratio (mass%) of the mass of the heat residue to the mass of the aqueous dispersion (1 g) was determined.

[0467] <Composition of the fluorine-containing elastomer> Determined by NMR analysis.

[0468] <Mooney viscosity> The Mooney viscosity was measured at 100 °C in accordance with JIS K 6300-1.2013 using a Mooney viscometer model MV2000E manufactured by ALPHA TECHNOLOGIES.

[0469] <Polymer adhesion rate> The ratio (adhesion rate to the polymerization tank) of the mass of the polymer deposit adhering to the polymerization tank after the completion of polymerization to the total amount of the polymer (fluorine-containing elastomer) after the completion of polymerization was determined by the following formula. Polymer adhesion rate (mass%) = mass of polymer deposit / mass of the obtained polymer (including polymer deposit) × 100 Mass of the obtained polymer = mass of the aqueous dispersion × solid content concentration of the aqueous dispersion (mass%) / 100 + mass of the polymer deposit The polymer deposit includes the polymer adhering to the inside of the polymerization tank such as the inner wall of the polymerization tank and the stirring blade after the aqueous dispersion is withdrawn from the polymerization tank after the completion of polymerization, and the polymer that has been released from the aqueous dispersion by aggregation and is floating or precipitating without being dispersed in the aqueous dispersion. The mass of the polymer deposit is the mass after drying and removing the moisture contained in the polymer deposit at 120 °C.

[0470] <Polymerization rate> Calculated by the following formula. Polymerization rate = {weight of aqueous dispersion × solid content concentration / 100} / {(amount of pure water used in polymerization + amount of water contained in the aqueous solution of polymer (1) used in polymerization) × polymerization time} The units of each quantity in the formula are as follows. Weight of aqueous dispersion: g Solid content concentration: mass% Amount of pure water used in polymerization: kg Amount of water contained in the aqueous solution of polymer (1) used in polymerization: kg Polymerization time: hours Polymerization rate: g / (hour × kg)

[0471] <Average particle diameter> The average particle diameter (cumulant average diameter) of the fluorine-containing elastomer particles in the aqueous dispersion was measured by the dynamic light scattering method using an ELSZ-1000S (manufactured by Otsuka Electronics Co., Ltd.) and calculated by the cumulant method.

[0472] <Number of fluorine-containing elastomer particles in the aqueous dispersion> It was calculated by the following formula.

[0473]

Equation

[0474] In the formula, the average particle diameter is the cumulant average diameter calculated by the method described above, the number of polymer particles (number of fluorine-containing elastomer particles) is the number per 1 cc of water, and the specific gravity of all the fluorine-containing elastomers in the examples was assumed to be 1.8.

[0475] Preparation Example 1 110 g of monomer A represented by CF2=CFOCF2CF2COOH and 220 g of water were added with ammonium persulfate (APS), and stirred at 52 °C for 96 hours under a nitrogen atmosphere to obtain an aqueous solution A-1 of polymer A containing polymer A which is a homopolymer of CF2=CFOCF2CF2COOH. APS was added appropriately during the reaction and a total of 5 mol% was used. The oxygen concentration in the reactor changed in the range of 11 volume ppm to 61 volume ppm. As a result of GPC analysis of the obtained aqueous solution A-1 of polymer A, polymer A had Mw = 15,000 and Mn = 10,000. Water was added to the obtained aqueous solution A-1 of polymer A to adjust the concentration to 2.2 mass% (aqueous solution A-2 of polymer A).

[0476] Preparation Example 2 30 g of monomer B represented by CF2=CFOCF2CF(CF3)OCF2CF2COOH, 60 g of water, 0.5 eq of NH3 (an amount corresponding to 0.5 equivalent relative to monomer B), and 2 mol% of APS were added, and the mixture was stirred at 52 °C for 72 hours under a nitrogen atmosphere to obtain an aqueous solution B-1 of polymer B containing a homopolymer of CF2=CFOCF2CF(CF3)OCF2CF2COOH as polymer B. The oxygen concentration in the reactor changed in the range of 20 to 50 volume ppm. As a result of GPC analysis of the obtained aqueous solution B-1 of polymer B, the polymer B had Mw = 14,000 and Mn = 9,000. Water and 0.4 eq of NH3 (an amount corresponding to 0.4 equivalent relative to monomer B used for polymerization) were added to the obtained aqueous solution B-1 of polymer B, and the concentration was adjusted to 1.9 mass% (aqueous solution B-2 of polymer B).

[0477] Example 1 1466 g of deionized water and 34.09 g of an aqueous solution A-2 of polymer A (2.2 mass%) were added to a 3 L SUS polymerization tank, the polymerization tank was sealed, and the inside of the system was replaced with nitrogen to remove oxygen. The polymerization tank was heated to 80 °C, and while stirring, a monomer (initial monomer) was press-fitted at a molar ratio of vinylidene fluoride [VDF] / tetrafluoroethylene [TFE] / hexafluoropropylene [HFP] (=19 / 11 / 70 mol%) so that the internal pressure of the polymerization tank became 1.47 MPaG.

[0478] Next, an aqueous solution of a polymerization initiator in which 0.026 g of ammonium persulfate (APS) was dissolved in deionized water was press-fitted with nitrogen gas to initiate polymerization. When the internal pressure dropped to 1.45 MPaG as the polymerization progressed, a mixed monomer of VDF / TFE / HFP (=50 / 20 / 30 mol%) was charged so that the internal pressure became constant at 1.47 MPaG.

[0479] When 14 g of the mixed monomer was additionally added, 2.19 g of diiodine compound I (CF2)4I was press-fitted with nitrogen gas.

[0480] 3.0 hours, 6.0 hours, and 9.0 hours after the start of polymerization, an aqueous solution of a polymerization initiator of 0.026 g of APS was press-fitted with nitrogen gas, respectively.

[0481] When 477 g of the mixed monomer was added, stirring was stopped and the polymerization vessel was depressurized until it reached atmospheric pressure. The polymerization vessel was cooled to obtain an aqueous dispersion. The results are shown in Table 1.

[0482] An aqueous aluminum sulfate solution was added to the above aqueous dispersion for coagulation. The obtained coagulum was washed with water and dried to obtain a fluorine-containing elastomer. The Mooney viscosity of the fluorine-containing elastomer was ML1+10(100°C)=54.9. When the copolymer composition was examined by NMR analysis, it was VDF / TFE / HFP = 50 / 20 / 30 (mol%).

[0483] Example 2 The experiment was carried out under the same conditions as in Example 1, except that 34.09 g of the aqueous solution A-2 (2.2 mass%) of polymer A was neutralized with aqueous ammonia to a pH of 5.6 and then added to the polymerization vessel.

[0484] The polymerization vessel was cooled to obtain an aqueous dispersion. The results are shown in Table 1.

[0485] An aqueous aluminum sulfate solution was added to the above aqueous dispersion for coagulation. The obtained coagulum was washed with water and dried to obtain a fluorine-containing elastomer. The Mooney viscosity of the fluorine-containing elastomer was ML1+10(100°C)=54.7. When the copolymer composition was examined by NMR analysis, it was VDF / TFE / HFP = 50 / 20 / 30 (mol%).

[0486] Example 3 Using 1460 g of deionized water, and replacing 34.09 g of the aqueous solution A-2 (2.2 mass%) of polymer A with 40.32 g of the aqueous solution B-2 (1.9 mass%) of polymer B, and adding an aqueous solution of 0.026 g of APS as a polymerization initiator into the polymerization vessel by nitrogen gas pressure injection at 3.0 hours and 6.0 hours after the start of polymerization, the experiment was carried out under the same conditions as in Example 1.

[0487] The polymerization vessel was cooled to obtain an aqueous dispersion. The results are shown in Table 1.

[0488] An aqueous solution of aluminum sulfate was added to the above aqueous dispersion for coagulation. The obtained coagulum was washed with water and dried to obtain a fluorine-containing elastomer. The Mooney viscosity of the fluorine-containing elastomer was ML1+10(100°C)=63.9. When the copolymer composition was examined by NMR analysis, it was found to be VDF / TFE / HFP = 50 / 20 / 30 (mol%).

[0489]

Table 1

[0490] Crosslinking characteristics The fluorine-containing elastomers obtained in Examples 1 to 3 were kneaded with the formulations shown in Table 2 to obtain fluorine-containing elastomer compositions. For the obtained fluorine-containing elastomer compositions, a crosslinking curve was determined using a rubber vulcanization tester MDRH2030 (manufactured by M & C Co., Ltd.) during press crosslinking, and the minimum viscosity (ML), maximum torque level (MH), induction time (T10), and optimum crosslinking time (T90) were determined. Further, by crosslinking the fluorine-containing elastomer composition by press crosslinking and oven crosslinking following the press crosslinking, a crosslinked molded product sheet was obtained. Kneading method: Roll kneading Press crosslinking: 10 minutes at 160°C Oven crosslinking: 4 hours at 180°C

[0491] The materials shown in Table 2 are as follows. MT carbon: Thermax N-990 manufactured by Cancarb TAIC: Triallyl isocyanurate, manufactured by Taiyo Nippon Chemical Co., Ltd. Perhexa 25B: 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, manufactured by NOF Corporation

[0492] Normal physical properties Using the crosslinked molded product sheet, test pieces in the shape of dumbbell No. 6 were prepared in accordance with JIS K6251, and the 100% modulus (M100), tensile strength at break (TB), and elongation at break (EB) of the prepared test pieces in the normal state were measured.

[0493] Hardness In the same manner as described above, a dumbbell No. 6-shaped test piece was prepared, and the hardness (Shore A) of the prepared test piece was measured in accordance with JIS K6253 (peak value, 1 sec, 3 sec).

[0494] Compression set Using the fluorine-containing elastomer composition, press crosslinking and oven crosslinking were performed under the above-mentioned conditions to produce an O-ring (P24 size), and in accordance with JIS K6262, the compression set of the produced O-ring was measured under the conditions of 200 °C, 72 hours, and a compression ratio of 25%.

[0495] The above results are shown in Table 2.

[0496]

Table 2

Claims

1. A method for producing an aqueous dispersion of a fluorine-containing elastomer by polymerizing a fluorine-containing monomer in the presence of a polymer (1) containing a polymerized unit (1) based on a monomer (1) represented by the general formula (1) and an aqueous medium, wherein the fluorine-containing elastomer contains -CH₂- in the main chain. CF ２ = CF - R - CZ １ Z ２ -COOM (1) (wherein R is a linking group, and Z １ and Z ２ are each independently F or CF ３ , M is H, a metal atom, NR ７ ４ , optionally substituted imidazolium, optionally substituted pyridinium or optionally substituted phosphonium, and R ７ is H or an organic group.)

2. The production method according to claim 1, wherein the monomer (1) is a monomer (2) represented by the general formula (2). CF ２ = CF(−O−Rf−COOM) (2) (In the formula, Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms, or a fluorine-containing alkylene group having an ether bond or a keto group and having 2 to 100 carbon atoms, and M is as described above.)

3. The weight-average molecular weight of the polymer (1) is 1.4 × 10 ４ or more, and the production method according to claim 1 or 2.

4. The production method according to any one of claims 1 to 3, wherein the content of the polymerized unit (1) is 50 mol% or more based on all the polymerized units constituting the polymer (1).

5. The production method according to any one of claims 1 to 4, wherein the addition amount of the polymer (1) is 0.0001 to 2% by mass based on 100% by mass of the aqueous medium.

6. The polymerization of the fluorine-containing monomer is carried out in the presence of a polymerization initiator, and the addition amount of the polymerization initiator is 0.00001 to 10% by mass based on 100% by mass of the fluorine-containing monomer. The production method according to any one of claims 1 to 5.

7. The production method according to any one of claims 1 to 6, wherein the polymerization of the fluorine-containing monomer is carried out substantially in the absence of a fluorine-containing surfactant.

8. The production method according to any one of claims 1 to 7, wherein the fluorine-containing monomer is vinylidene fluoride or tetrafluoroethylene.

9. The production method according to any one of claims 1 to 8, wherein the fluorine-containing monomer is vinylidene fluoride.

10. A composition containing a fluorine-containing elastomer and a polymer (1) containing a polymerized unit (1) based on a monomer (1) represented by the general formula (1), wherein the fluorine-containing elastomer contains -CH₂- in the main chain. CF ２ = CF - R - CZ １ Z ２ -COOM (1) (In the formula, R is a linking group, and Z １ and Z ２ are each independently F or CF ３ , M is H, a metal atom, NR ７ ４ , an optionally substituted imidazolium, an optionally substituted pyridinium or an optionally substituted phosphonium, and R ７ is H or an organic group.)

11. The composition according to claim 10, wherein the monomer (1) is a monomer (2) represented by the general formula (2). CF ２ = CF(−O−Rf−COOM) (2) (In the formula, Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms, or a fluorine-containing alkylene group having an ether bond or a keto group and having 2 to 100 carbon atoms, and M is as described above.)

12. The weight-average molecular weight of the polymer (1) is 1.4 × 10 ４ or more, and the composition according to claim 10 or 11.

13. The composition according to any one of claims 10 to 12, wherein the content of the repeating unit (1) is 50 mol% or more based on all the repeating units constituting the polymer (1).

14. The composition according to any one of claims 10 to 13, wherein the content of the polymer (1) is 0.00001 to 20% by mass based on the fluorine-containing elastomer.

15. The composition according to any one of claims 10 to 14, which is an aqueous dispersion.

16. The composition according to claim 15, wherein the solid content concentration of the aqueous dispersion is 5 to 50% by mass based on the aqueous dispersion.

17. The composition according to any one of claims 10 to 16, which substantially does not contain a fluorine-containing surfactant.

18. The composition according to any one of claims 10 to 17, wherein the fluorine-containing elastomer contains a vinylidene fluoride unit or a tetrafluoroethylene unit.

19. The composition according to any one of claims 10 to 18, wherein the fluorine-containing elastomer contains a vinylidene fluoride unit.

Images