Fluoropolymers, aqueous solutions and coating compositions

Abstract

This invention provides a fluoropolymer, which is a fluoropolymer of monomer (I) represented by general formula (I), wherein the content of polymeric unit (I) based on monomer (I) is 50% by mass or more relative to all polymeric units constituting the above-mentioned fluoropolymer. General formula (I): CX2=CX-O-Rf-SO3M (where X is independently F or CF3, Rf is a fluorinated alkylene group having 1 to 40 carbon atoms, or a fluorinated alkylene group having ether or ketone groups having 2 to 100 carbon atoms. M is -H, a metal atom, or -NR.) 7 4. Imidazolium with or without substituents, pyridinium with or without substituents, or phosphonium with or without substituents, R 7 (It is an H or an organic group).

Description

Technical Field

[0001] This disclosure relates to fluoropolymers, aqueous solutions, and coating compositions. Background Technology

[0002] Patent document 1 describes a copolymer consisting of a polymeric unit based on vinylidene fluoride and a polymeric unit having a side chain containing -CF2COOLi or -CF2SO3Li.

[0003] Patent document 2 describes a polymer that is essentially composed of the following repeating units,

[0004] (A)-CF2-CFL-

[0005] (L = F, CF3 or R) F O-, R F (C1 to C5 perfluoroalkyl)

[0006] (B)-CF2-CF[-O-(CF2CFCF3O) K -(CF2)3-SO3M]-

[0007] (K = 0 or 1, M = H, metal or ammonium ion)

[0008] The ratio of the number of repeating units is in the range of (A) / (B) = 1.5 to 14.

[0009] Patent document 3 describes a highly fluorinated sulfinic acid oligomer.

[0010] Existing technical documents

[0011] Patent documents

[0012] Patent Document 1: Japanese Patent Application Publication No. 10-284128

[0013] Patent Document 2: Japanese Patent Application Publication No. 57-92025

[0014] Patent Document 3: Japanese Patent Publication No. 2014-504293 Summary of the Invention

[0015] The problem that the invention aims to solve

[0016] The purpose of this disclosure is to provide a fluoropolymer that enables the preparation of a coating composition containing a high concentration of the fluoropolymer, and which can be used to form a coating film with uniform thickness even when the coating composition contains a high concentration of the fluoropolymer.

[0017] Methods for solving problems

[0018] According to this disclosure, a fluoropolymer is provided, which is a fluoropolymer of monomer (I) represented by general formula (I), wherein the content of polymeric unit (I) based on monomer (I) is 50% by mass or more relative to all polymeric units constituting the fluoropolymer.

[0019] General formula (I): CX2=CX-O-Rf-SO3M

[0020] (In the formula, X is independently F or CF3, Rf is a fluorinated alkylene group with 1 to 40 carbon atoms, or a fluorinated alkylene group with ether or ketone groups having 2 to 100 carbon atoms. M is -H, a metal atom, or -NR.) 7 4. Imidazolium with or without substituents, pyridinium with or without substituents, or phosphonium with or without substituents, R 7 (It is an H group or an organic group.)

[0021] The preferred weight-average molecular weight (Mw) of the fluoropolymer disclosed herein is 0.6 × 10⁻⁶. 4 above.

[0022] The preferred molecular weight distribution (Mw / Mn) of the fluoropolymer disclosed herein is 3.0 or less.

[0023] In general formula (I), X is preferably F.

[0024] In general formula (I), Rf is preferably a fluorinated alkylene group having 1 to 5 carbon atoms, or a fluorinated alkylene group having 2 to 5 carbon atoms and having an ether bond or a ketone group.

[0025] The fluoropolymer disclosed herein is preferably a copolymer of monomer (I) and monomer represented by the general formula CFR=CR2 (where R is independently H, F or a perfluoroalkyl group having 1 to 4 carbon atoms).

[0026] When the fluoropolymer disclosed herein is a copolymer, it is preferable that: the content of polymeric unit (I) based on monomer (I) is 50% to 94% by mass relative to all polymeric units constituting the above-mentioned fluoropolymer; and the content of polymeric unit (M) based on monomer represented by the general formula CFR=CR2 (where R is independently H, F or a perfluoroalkyl group having 1 to 4 carbon atoms) is 6% to 50% by mass relative to all polymeric units constituting the above-mentioned fluoropolymer.

[0027] When the fluoropolymer disclosed herein is a copolymer, it is preferable that the alternation rate of polymeric unit (I) and polymeric unit (M) is 40% or more.

[0028] The preferred fluoropolymer disclosed herein is that the content of polymer unit (I) is 99% by mass or more relative to all polymer units constituting the fluoropolymer.

[0029] The fluoropolymers disclosed herein are preferably composed of only polymer units (I).

[0030] The fluoropolymers disclosed herein are preferably dimers and trimers that are substantially free of monomer (I).

[0031] The preferred fluoropolymer disclosed herein has a content of fractions with a molecular weight of 3000 or less of 0.5% relative to the fluoropolymer.

[0032] In addition, according to this disclosure, an aqueous solution containing the above-mentioned fluoropolymer is provided.

[0033] Preferably, the aqueous solution disclosed herein contains 2% by mass or more of the fluoropolymer relative to the aqueous solution.

[0034] In addition, according to this disclosure, a coating composition containing the above-mentioned fluoropolymer or the above-mentioned aqueous solution is provided.

[0035] The effects of the invention

[0036] According to this disclosure, it is possible to prepare coating compositions containing high concentrations of fluoropolymers, and to provide fluoropolymers that can form coating films with uniform film thickness even when the coating composition contains high concentrations of fluoropolymers. Detailed Implementation

[0037] Before providing a detailed description of this disclosure, some terms used in this disclosure will be defined or explained.

[0038] In this disclosure, "organic group" refers to a group containing one or more carbon atoms, or a group formed by removing one hydrogen atom from an organic compound.

[0039] Examples of this "organic group" include:

[0040] Alkyl groups that can have more than one substituent

[0041] Alkenes that can have more than one substituent

[0042] Alkyne groups can have more than one substituent.

[0043] Cycloalkyl groups can have more than one substituent.

[0044] Cycloalkenyl groups can have more than one substituent.

[0045] Cyclodiene groups can have more than one substituent.

[0046] Aryl groups can have more than one substituent.

[0047] Aryl groups can have more than one substituent.

[0048] Non-aromatic heterocyclic groups that can have more than one substituent

[0049] Heteroaryl groups that can have more than one substituent

[0050] cyano,

[0051] formyl group,

[0052] RaO-、

[0053] RaCO-、

[0054] RaSO2-、

[0055] RaCOO-、

[0056] RaNRaCO-、

[0057] RaCONRa-、

[0058] RaOCO-、

[0059] RaOSO2-, and

[0060] RaNRbSO2-

[0061] (In these formulas, Ra is independently:)

[0062] Alkyl groups that can have more than one substituent

[0063] Alkenes that can have more than one substituent

[0064] Alkyne groups can have more than one substituent.

[0065] Cycloalkyl groups can have more than one substituent.

[0066] Cycloalkenyl groups can have more than one substituent.

[0067] Cyclodiene groups can have more than one substituent.

[0068] Aryl groups can have more than one substituent.

[0069] Aryl groups can have more than one substituent.

[0070] It can be a non-aromatic heterocyclic group with more than one substituent, or

[0071] Heteroaryl groups can have more than one substituent.

[0072] Rb is independently H or may be an alkyl group having more than one substituent.

[0073] As the aforementioned organic group, it is preferable to have an alkyl group having one or more substituents.

[0074] Furthermore, in this disclosure, "substituent" refers to a group capable of substitution. Examples of such "substituents" include: aliphatic groups, aromatic groups, heterocyclic groups, acyl groups, acyloxy groups, amide groups, aliphatic oxy groups, aromatic oxy groups, heterocyclic oxy groups, aliphatic oxycarbonyl groups, aromatic oxycarbonyl groups, heterocyclic oxycarbonyl groups, carbamoyl groups, aliphatic sulfonyl groups, aromatic sulfonyl groups, heterocyclic sulfonyl groups, aliphatic sulfonyloxy groups, aromatic sulfonyloxy groups, heterocyclic sulfonyloxy groups, amino sulfonyl groups, aliphatic sulfonamide groups, aromatic sulfonamide groups, heterocyclic sulfonamide groups, amino groups, and aliphatic groups. Aliphatic amino, aromatic amino, heterocyclic amino, aliphatic oxycarbonyl amino, aromatic oxycarbonyl amino, heterocyclic oxycarbonyl amino, aliphatic sulfinyl, aromatic sulfinyl, aliphatic thio, aromatic thio, hydroxyl, cyano, sulfonyl, carboxyl, aliphatic oxyamino, aromatic oxyamino, carbamoylamino, aminosulfonylamino, halogen atom, aminosulfonylcarbamoyl, carbamoylaminosulfonyl, dialiphatic oxyphosphine, and diaromatic oxyphosphine.

[0075] The aforementioned aliphatic groups can be saturated or unsaturated. Furthermore, they may include hydroxyl, aliphatic oxygen, carbamoyl, aliphatic oxygen carbonyl, aliphatic thio, amino, aliphatic amino, amide, carbamoylamino, etc. Examples of aliphatic groups include alkyl groups with a total carbon number of 1 to 8, preferably 1 to 4, such as methyl, ethyl, vinyl, cyclohexyl, carbamoylmethyl, etc.

[0076] The aforementioned aromatic groups may include, for example, nitro, halogen, aliphatic oxygen, carbamoyl, aliphatic oxygen carbonyl, aliphatic thio, amino, aliphatic amino, amide, carbamoylamino, etc. Examples of such aromatic groups include aryl groups with 6 to 12 carbon atoms, preferably 6 to 10 total carbon atoms, such as phenyl, 4-nitrophenyl, 4-acetylaminophenyl, 4-methanesulfonylphenyl, etc.

[0077] The aforementioned heterocyclic group may have halogen atoms, hydroxyl groups, aliphatic oxygen groups, carbamoyl groups, aliphatic oxygen carbonyl groups, aliphatic thio groups, amino groups, aliphatic amino groups, amide groups, carbamoylamino groups, etc. Examples of such heterocyclic groups include 5- to 6-membered heterocycles with a total number of carbon atoms of 2 to 12, preferably 2 to 10, such as 2-tetrahydrofuranyl and 2-pyrimidinyl groups.

[0078] The aforementioned acyl group may be aliphatic carbonyl, aryl carbonyl, heterocyclic carbonyl, hydroxyl, halogen atom, aromatic group, aliphatic oxygen group, carbamoyl, aliphatic oxygen carbonyl, aliphatic thio, amino, aliphatic amino, amide, carbamoylamino, etc. Examples of such acyl groups include those with a total carbon number of 2 to 8, preferably 2 to 4, such as acetyl, propionyl, benzoyl, 3-pyridine carbonyl, etc.

[0079] The aforementioned amide groups may have aliphatic groups, aromatic groups, heterocyclic groups, etc., such as acetylamino, benzoylamino, 2-pyridine carbonylamino, propionylamino, etc. Examples of such amide groups include amide groups with a total carbon number of 2 to 12, preferably 2 to 8, and alkyl carbonylamino groups with a total carbon number of 2 to 8, such as acetylamino, benzoylamino, 2-pyridine carbonylamino, propionylamino, etc.

[0080] The aforementioned aliphatic oxycarbonyl group can be saturated or unsaturated. Furthermore, it can be hydroxyl, aliphatic oxy, carbamoyl, aliphatic oxycarbonyl, aliphatic thio, amino, aliphatic amino, amide, carbamoylamino, etc. Examples of aliphatic oxycarbonyl groups include alkoxycarbonyl groups with a total carbon number of 2 to 8, preferably 2 to 4, such as methoxycarbonyl, ethoxycarbonyl, and (tert-)butoxycarbonyl.

[0081] The aforementioned carbamoyl group may have an aliphatic group, an aromatic group, a heterocyclic group, etc. Examples of the aforementioned carbamoyl group include unsubstituted carbamoyl groups and alkyl carbamoyl groups with a total number of carbon atoms of 2 to 9. Preferred examples include unsubstituted carbamoyl groups, alkyl carbamoyl groups with a total number of carbon atoms of 2 to 5, such as N-methylcarbamoyl groups, N,N-dimethylcarbamoyl groups, and N-phenylcarbamoyl groups.

[0082] The aforementioned aliphatic sulfonyl groups can be saturated or unsaturated. Furthermore, they can include hydroxyl groups, aromatic groups, aliphatic oxygen groups, carbamoyl groups, aliphatic oxygen carbonyl groups, aliphatic thio groups, amino groups, aliphatic amino groups, amide groups, carbamoylamino groups, etc. Examples of aliphatic sulfonyl groups include alkyl sulfonyl groups with a total carbon number of 1 to 6, preferably 1 to 4, such as methanesulfonyl groups.

[0083] The aforementioned aromatic sulfonyl groups may have hydroxyl, aliphatic, aliphatic oxygen, carbamoyl, aliphatic oxygen carbonyl, aliphatic thio, amino, aliphatic amino, amide, carbamoylamino, etc. Examples of such aromatic sulfonyl groups include arylsulfonyl groups with a total number of carbon atoms of 6 to 10, such as benzenesulfonyl groups.

[0084] The aforementioned amino groups can have aliphatic groups, aromatic groups, heterocyclic groups, etc.

[0085] The aforementioned acylamino group may be, for example, acetylamino, benzoylamino, 2-pyridine carbonylamino, propionylamino, etc. Examples of such acylamino groups include those with a total carbon number of 2 to 12, preferably 2 to 8, and more preferably alkyl carbonylamino groups with a total carbon number of 2 to 8, such as acetylamino, benzoylamino, 2-pyridine carbonylamino, propionylamino, etc.

[0086] The aforementioned aliphatic sulfonamide group, aromatic sulfonamide group, and heterocyclic sulfonamide group can be, for example, methylsulfonamide group, benzenesulfonamide group, 2-pyridinesulfonamide group, etc.

[0087] The aforementioned aminosulfonyl group may have an aliphatic group, an aromatic group, a heterocyclic group, etc. Examples of the aforementioned aminosulfonyl group include aminosulfonyl, alkyl aminosulfonyl with 1 to 9 total carbon atoms, dialkyl aminosulfonyl with 2 to 10 total carbon atoms, aryl aminosulfonyl with 7 to 13 total carbon atoms, heterocyclic aminosulfonyl with 2 to 12 total carbon atoms, more preferably aminosulfonyl, alkyl aminosulfonyl with 1 to 7 total carbon atoms, dialkyl aminosulfonyl with 3 to 6 total carbon atoms, aryl aminosulfonyl with 6 to 11 total carbon atoms, heterocyclic aminosulfonyl with 2 to 10 total carbon atoms, such as aminosulfonyl, methyl aminosulfonyl, N,N-dimethylaminosulfonyl, phenyl aminosulfonyl, 4-pyridine aminosulfonyl, etc.

[0088] The aforementioned aliphatic oxygen groups can be saturated or unsaturated, and may include methoxy, ethoxy, isopropoxy, cyclohexyloxy, methoxyethoxy, etc. Examples of aliphatic oxygen groups include alkoxy groups with a total carbon number of 1 to 8, preferably 1 to 6, such as methoxy, ethoxy, isopropoxy, cyclohexyloxy, methoxyethoxy, etc.

[0089] The aforementioned aromatic amino groups and heterocyclic amino groups may have aliphatic groups, aliphatic oxygen groups, halogen atoms, carbamoyl groups, heterocyclic groups fused with the aryl group, and aliphatic oxygen carbonyl groups. Preferably, they may have aliphatic groups with a total number of carbon atoms of 1 to 4, aliphatic oxygen groups with a total number of carbon atoms of 1 to 4, halogen atoms, carbamoyl groups with a total number of carbon atoms of 1 to 4, nitro groups, and aliphatic oxygen carbonyl groups with a total number of carbon atoms of 2 to 4.

[0090] The aforementioned aliphatic thio groups can be saturated or unsaturated. In addition, they can have alkylthio groups with a total number of carbon atoms of 1 to 8, more preferably alkylthio groups with a total number of carbon atoms of 1 to 6, such as methylthio, ethylthio, carbamoylmethylthio, tert-butylthio, etc.

[0091] The aforementioned carbamoylamino group may have an aliphatic group, an aryl group, a heterocyclic group, etc. Examples of the aforementioned carbamoylamino group include carbamoylamino, alkyl carbamoylamino with 2 to 9 total carbon atoms, dialkyl carbamoylamino with 3 to 10 total carbon atoms, aryl carbamoylamino with 7 to 13 total carbon atoms, and heterocyclic carbamoylamino with 3 to 12 total carbon atoms. Preferably, carbamoylamino, alkyl carbamoylamino with 2 to 7 total carbon atoms, dialkyl carbamoylamino with 3 to 6 total carbon atoms, aryl carbamoylamino with 7 to 11 total carbon atoms, and heterocyclic carbamoylamino with 3 to 10 total carbon atoms, such as carbamoylamino, methyl carbamoylamino, N,N-dimethyl carbamoylamino, phenyl carbamoylamino, 4-pyridine carbamoylamino, etc.

[0092] In this disclosure, the range represented by the endpoints includes all values ​​contained in that range (e.g., 1 to 10 includes 1.4, 1.9, 2.33, 5.75, 9.98, etc.).

[0093] In this disclosure, the term "at least 1" includes all values ​​greater than 1 (e.g., at least 2, at least 4, at least 6, at least 8, at least 10, at least 25, at least 50, at least 100, etc.).

[0094] The following describes in detail the specific embodiments of this disclosure, but this disclosure is not limited to the following embodiments.

[0095] The fluoropolymer disclosed herein is a polymer of monomer (I) represented by general formula (I).

[0096] General formula (I): CX2=CX-O-Rf-SO3M

[0097] (In the formula, X is independently F or CF3, Rf is a fluorinated alkylene group with 1 to 40 carbon atoms, or a fluorinated alkylene group with ether or ketone groups having 2 to 100 carbon atoms. M is -H, a metal atom, or -NR.) 7 4. Imidazolium with or without substituents, pyridinium with or without substituents, or phosphonium with or without substituents, R 7 (It is an H group or an organic group.)

[0098] Fluoropolymers can be homopolymers consisting solely of polymerization units (I) based on monomer (I), or copolymers comprising polymerization units (I) and polymerization units based on other monomers capable of copolymerizing with monomer (I). The polymerization units (I) may be the same or different each time they appear, and fluoropolymers may contain polymerization units (I) based on monomers represented by two or more different general formulas (I).

[0099] In the fluoropolymer, the content of polymeric unit (I) based on monomer (I) is 50% by mass or more relative to all polymeric units constituting the fluoropolymer. The content of polymeric unit (I) in the fluoropolymer is preferably 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, and 99% by mass or more, respectively, relative to all polymeric units constituting the fluoropolymer. The content of polymeric unit (I) is particularly preferably substantially 100% by mass, and the fluoropolymer is most preferably composed solely of polymeric unit (I). A high content of polymeric unit (I) in the fluoropolymer has the advantage of improved water solubility. Furthermore, since the fluoropolymer of this disclosure contains a large amount of polymeric unit (I), when used in coating compositions, it is possible to prepare coating compositions containing a high concentration of fluoropolymer, and even when the coating composition contains a high concentration of fluoropolymer, it is possible to form a coating film with uniform film thickness using the coating composition.

[0100] In the fluoropolymer, the content of polymerization units based on other monomers capable of copolymerizing with monomer (I) is preferably 50% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less, 10% by mass or less, and 1% by mass or less, respectively, relative to the total number of polymerization units constituting the fluoropolymer. Particularly preferably, the content of polymerization units based on other monomers capable of copolymerizing with monomer (I) is substantially 0% by mass, and the fluoropolymer most preferably contains no polymerization units based on other monomers.

[0101] The lower limit of the number-average molecular weight of fluoropolymers is preferably 0.3 × 10⁻⁶. 4 Above, 0.4×10 4 Above, 0.5×10 4 Above, 0.7×10 4 Above, 0.8×10 4 Above, 1.0×10 4 Above, 1.2×10 4 Above, 1.4×10 4 1.6×10 4 Above, 1.8×10 4 Above, 2.0×10 4 Above, 3.0×10 4 The above. The upper limit of the number-average molecular weight of the fluoropolymer is preferably 75.0 × 10⁻⁶. 4 Below, 50.0×10 4 Below, 40.0×10 4 Below, 30.0×10 4 Below, 20.0×10 4 the following.

[0102] The lower limit of the weight-average molecular weight of fluoropolymers is preferably 0.4 × 10⁻⁶. 4 Above, 0.5×10 4 Above, 0.6×10 4 Above, 0.8×10 4 Above, 1.0×10 4 Above, 1.2×10 4 Above, 1.4×10 4 Above, 1.7×10 4 Above, 1.9×10 4 Above, 2.1×10 4 Above, 2.3×10 4 Above, 2.7×10 4 Above, 3.1×10 4 Above, 3.5×10 4 Above, 3.9×10 4 Above, 4.3×10 4 Above, 4.7×10 4 Above, 5.1×10 4 Above, 10.0×10 4 Above, 15.0×10 4 Above, 20.0×10 4 Above, 25.0×10 4 The above. The upper limit of the weight-average molecular weight of the fluoropolymer is preferably 150.0 × 10⁻⁶. 4 Below, 100.0×10 4 Below, 60.0×10 4 Below, 50.0×10 4 Below, 40.0×10 4 the following.

[0103] The molecular weight distribution (Mw / Mn) of the fluoropolymer is preferably below 3.0, below 2.7, below 2.4, below 2.2, below 2.0, below 1.9, below 1.7, below 1.5, below 1.4, and below 1.3.

[0104] Number-average molecular weight (NMA) and weight-average molecular weight (JMA) are calculated using gel permeation chromatography (GPC) with monodisperse polyethylene oxide (PEO) and polyethylene glycol (PEG) as standards. Alternatively, when GPC is not feasible, the NMA of the fluoropolymer can be determined based on the correlation between the NMA calculated from the number of terminal groups obtained by NMR, FT-IR, etc., and the melt flow rate. The melt flow rate can be determined according to JIS K 7210.

[0105] The acid value of the fluoropolymer is preferably 60 or higher, more preferably 90 or higher, even more preferably 120 or higher, particularly preferably 150 or higher, most preferably 180 or higher, with no particular upper limit, but preferably below 300.

[0106] The acid value of fluoropolymers is determined by the presence of -SO3M (where M is a metal atom) in addition to -SO3H, i.e., -SO3M (where M is a metal atom, -NR). 7 4. In the case of imidazolium with or without substituents, pyridinium with or without substituents, or phosphonium with or without substituents, the determination can be made by acid-base titration of -SO3H after converting -SO3M to -SO3H.

[0107] The monomer (I) is represented by the general formula (I).

[0108] General formula (I): CX2=CX-O-Rf-SO3M

[0109] In the formula, X is independently either F or CF3. Preferably, at least one X is F, and more preferably, all X are F.

[0110] In the formula, Rf represents a fluorinated alkylene group with 1 to 40 carbon atoms, a fluorinated alkylene group with 2 to 100 carbon atoms and an ether bond, or a fluorinated alkylene group with 2 to 100 carbon atoms and a ketone group. It should be noted that the aforementioned fluorinated alkylene groups with 2 to 100 carbon atoms and an ether bond do not include structures with oxygen atoms at the end; they are alkylene groups containing ether bonds between carbon atoms.

[0111] The number of carbon atoms in the aforementioned fluorinated alkylene group is preferably 2 or more. Furthermore, the number of carbon atoms in the aforementioned fluorinated alkylene group is preferably 30 or less, more preferably 20 or less, further preferably 10 or less, and particularly preferably 5 or less. Examples of the aforementioned fluorinated alkylene group include -CF2-, -CH2CF2-, -CF2CF2-, -CF2CH2-, -CF2CF2CH2-, -CF(CF3)-, -CF(CF3)CF2-, -CF(CF3)CH2-, -CF2CF2CF2-, and -CF2CF2CF2CF2-. The fluorinated alkylene group is preferably a perfluoroalkylene group, and more preferably an unbranched, straight-chain perfluoroalkylene group.

[0112] The fluorinated alkylene group having an ether bond preferably has 3 or more carbon atoms. Furthermore, the fluorinated alkylene group having an ether bond preferably has 60 or fewer carbon atoms, more preferably 30 or fewer, even more preferably 12 or fewer, and particularly preferably 5 or fewer. The fluorinated alkylene group having an ether bond is also preferably, for example, of the general formula:

[0113] [Chemistry 1]

[0114]

[0115] (where Z) 1 For F or CF3; Z 2 and Z 3 H or F respectively; Z 4 The divalent group represented by 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.

[0116] Specifically, examples of the fluorinated alkylene groups having ether bonds mentioned above include -CF2CF(CF3)OCF2-, -CF2CF(CF3)OCF2CF2-, -CF2CF(CF3)OCF2CF2CF2-, -CF(CF3)CF2-O-CF(CF3)-, and -(CF(CF3)CF2-O). n -CF(CF3)-(where n is an integer from 1 to 10), -CF(CF3)CF2-O-CF(CF3)CH2-, -(CF(CF3)CF2-O) n -CF(CF3)CH2- (where n is an integer from 1 to 10), -CH2CF2CF2O-CH2CF2CH2-, -CF2CF2CF2O-CF2-, -CF2CF2CF2O-CF2CF2-, -CF2CF2CF2O-CF2CF2-, -CF2CF2CF2O-CF2CF2CF2-, -CF2CF2CF2O-CF2CF2CH2-, -CF2CF2O-CF2-, -CF2CF2O-CF2CH2-, etc. The fluorinated alkylene groups with ether bonds mentioned above are preferably perfluoroalkylene groups.

[0117] The fluorinated alkylene group having a ketone group preferably has 3 or more carbon atoms. Furthermore, the fluorinated alkylene group having a ketone group preferably has 60 or fewer carbon atoms, more preferably 30 or fewer, even more preferably 12 or fewer, and particularly preferably 5 or fewer.

[0118] Specifically, examples of the aforementioned fluorinated alkylene groups having a ketone group include -CF2CF(CF3)CO-CF2-, -CF2CF(CF3)CO-CF2CF2-, -CF2CF(CF3)CO-CF2CF2CF2-, and -CF2CF(CF3)CO-CF2CF2CF2CF2-. The fluorinated alkylene groups having a ketone group are preferably perfluoroalkylene groups.

[0119] Water can also be added to the ketone group in the fluorinated alkylene group. Therefore, monomer (I) can be a hydrate. Examples of fluorinated alkylene groups that have water added to the ketone group include -CF2CF(CF3)C(OH)2-CF2-, -CF2CF(CF3)C(OH)2-CF2CF2-, -CF2CF(CF3)C(OH)2-CF2CF2CF2-, and -CF2CF(CF3)C(OH)2-CF2CF2CF2CF2-.

[0120] M can be the same or different each time it appears, and can be H, a metal atom, or NR. 7 4. Imidazolium with or without substituents, pyridinium with or without substituents, or phosphonium with or without substituents, R 7 It is an H or an organic group.

[0121] As R 7 H or C are preferred 1-10 Organic groups, more preferably H or C 1-4 The organic groups, preferably H or C, are preferred. 1-4 Alkyl groups.

[0122] Examples of metal atoms include alkali metals (Group 1) and alkaline earth metals (Group 2), with Na, K, or Li being preferred.

[0123] As M, it can be the same or different each time it appears, and is preferably H, a metal atom or NR. 7 4. More preferably, H, alkali metals (Group 1), alkaline earth metals (Group 2), or NR. 7 4. Further preferred materials are H, Na, K, Li or NH4, even more preferred materials are H, Na, K or NH4, and most preferred materials are H, Na or NH4.

[0124] As monomer (I), from the viewpoint of further improving the water solubility of fluoropolymers, at least one monomer from the group consisting of monomers represented by free general formulas (1a), (1b), (1c), (1d) and (1e) is preferred.

[0125] CF2 = CF - O - (CF2) n1 -SO3M(1a)

[0126] (In the formula, n1 represents an integer from 1 to 10, and M is the same as above.)

[0127] CF2=CF-O-(CF2C(CF3)F) n2 -SO3M(1b)

[0128] (In the formula, n2 represents an integer from 1 to 5, and M is defined in the same way as above.)

[0129] CF2 = CF-O-(CFX) 1 ) n3 -SO3M(1c)

[0130] (where X) 1 (This represents F or CF3, where n3 represents an integer from 1 to 10, and M is defined the same as above.)

[0131] CF2 = CF-O-(CF2CFX) 1 O) n4 -(CF2) n6 -SO3M(1d)

[0132] (In the formula, n4 represents an integer from 1 to 10, n6 represents an integer from 1 to 3, and M and X) 1 Same as the definition above.

[0133] CF2 = CF-O - (CF2CF2CFX) 1 O) n5 -CF2CF2CF2-SO3M(1e)

[0134] (In the formula, n5 represents an integer from 0 to 10, M and X) 1 Same as the definition above.

[0135] In general formula (1a), n1 is preferably an integer of 5 or less, more preferably an integer of 3 or less, and even more preferably an integer of 2 or less. M is preferably H, Na, K, or NH4.

[0136] Examples of monomers represented by general formula (1a) include CF2=CFOCF2CF2SO3M, CF2=CFOCF2SO3M, CF2=CFOCF2CF2CF2SO3M, and CF2=CFOCF2CF2CF2CF2SO3M (where M is defined as above).

[0137] In general formula (1b), n2 is preferably an integer of 3 or less. M is preferably H, Na, K or NH4.

[0138] In general formula (1c), n3 is preferably an integer of 5 or less, and M is preferably H, Na, K or NH4.

[0139] In general formula (1d), X 1 The preferred form is CF3, n4 is preferably an integer less than or equal to 5, and M is preferably H, Na, K or NH4.

[0140] As the monomer represented by the general formula (1d), examples include CF2=CFOCF2CF(CF3)OCF2SO3M, CF2=CFOCF2CF(CF3)OCF2CF2SO3M, and CF2=CFOCF2CF(CF3)OCF2CF2CF2SO3M (where M is the same as defined above).

[0141] In general formula (1e), n5 is preferably an integer less than or equal to 5, and M is preferably H, Na, K or NH4.

[0142] As a monomer represented by the general formula (1e), examples include CF2=CFOCF2CF2CF2SO3M (where M represents H, NH4 or an alkali metal).

[0143] Other monomers that can copolymerize with monomer (I) include monomers represented by the following general formula.

[0144] General formula: CX2 = CX - O - Rf - COOM

[0145] (In the formula, X, Rf, and M are as defined in general formula (I).)

[0146] As other monomers capable of copolymerizing with monomer (I), monomers represented by the general formula CFR=CR2 (where R is independently H, F, or a perfluoroalkyl group having 1 to 4 carbon atoms) are preferred. Furthermore, as other monomers capable of copolymerizing with monomer (I), fluorinated olefinic monomers having 2 or 3 carbon atoms are preferred. Examples of other monomers capable of copolymerizing with monomer (I) include CF2=CF2, CF2=CFCl, CH2=CF2, CFH=CH2, CFH=CF2, CF2=CFCF3, CH2=CFCF3, CH2=CHCF3, CHF=CHCF3 (E-form), and CHF=CHCF3 (Z-form).

[0147] As other monomers, from the perspective of good copolymerization, they are preferably selected from at least one of the group consisting of tetrafluoroethylene (CF2=CF2), trifluorochloroethylene (CF2=CFCl), and vinylidene fluoride (CH2=CF2), more preferably from at least one of the group consisting of tetrafluoroethylene and vinylidene fluoride, and even more preferably vinylidene fluoride. Therefore, the above-mentioned polymerization unit based on other monomers is preferably selected from at least one of the group consisting of polymerization units based on tetrafluoroethylene and polymerization units based on vinylidene fluoride, more preferably polymerization units based on vinylidene fluoride. The above-mentioned polymerization units based on other monomers may be the same or different in each occurrence, and the fluoropolymer may contain polymerization units based on two or more different other monomers.

[0148] When a fluoropolymer contains a polymerization unit (I) and polymerization units based on other monomers capable of copolymerizing with monomer (I), the content of polymerization unit (I) based on monomer (I) is preferably 50% to 94% by mass, more preferably 63% to 90% by mass, and even more preferably 67% to 87% by mass, relative to all polymerization units constituting the fluoropolymer. The content of polymerization units based on other monomers is preferably 6% to 50% by mass, more preferably 10% to 37% by mass, and even more preferably 13% to 33% by mass, relative to all polymerization units constituting the fluoropolymer. This configuration is particularly suitable when the polymerization unit based on other monomers capable of copolymerizing with monomer (I) is a polymerization unit (M) based on a monomer represented by the general formula CFR=CR2. When a fluoropolymer contains both polymerization unit (I) and polymerization unit (M), the total content of polymerization unit (I) and polymerization unit (M) is preferably 80% to 100% by mass, more preferably 85% by mass or more, even more preferably 90% by mass or more, and particularly preferably 99% by mass or more, relative to all polymerization units constituting the fluoropolymer. Furthermore, when the fluoropolymer contains a polymerization unit (I) and a polymerization unit (M1) of a monomer represented by CX2=CX-O-Rf-COOM, the total content of the polymerization unit (I) and the polymerization unit (M1) relative to all the polymerization units constituting the fluoropolymer is preferably 80% to 100% by mass, more preferably 85% by mass or more, even more preferably 90% by mass or more, and particularly preferably 99% by mass or more.

[0149] When a fluoropolymer contains a polymerization unit (I) and polymerization units based on other monomers capable of copolymerizing with monomer (I), the alternation rate between the polymerization unit (I) and the polymerization units based on other monomers capable of copolymerizing with monomer (I) is preferably 40% or more, more preferably 50% or more, further preferably 60% or more, even more preferably 70% or more, particularly preferably 80% or more, and most preferably 90% or more. The alternation rate can be, for example, 40 to 99%. This configuration is particularly suitable when the polymerization unit based on other monomers capable of copolymerizing with monomer (I) is a polymerization unit (M) based on a monomer represented by the general formula CFR = CR2.

[0150] The alternation rate of polymerization units (I) and other polymerization units based on monomers capable of copolymerizing with monomer (I) in fluoropolymers can be obtained through the fluoropolymer's... 19 It is determined by F-NMR analysis.

[0151] Other monomers can also be cited as examples of the general formula (n1-2):

[0152] [Chemistry 2]

[0153]

[0154] (where X) 1 X 2 Same or different, indicated by H or F; X 3 For example, H, F, Cl, CH3 or CF3; X 4 X 5 If they are the same or different, the value is H or F; if a and c are the same or different, the value is 0 or 1. Rf 3 Monomers represented by fluoroalkyl groups having 1 to 40 carbon atoms or fluoroalkyl groups having ether bonds having 2 to 100 carbon atoms.

[0155] Specifically, an example of a preferred option is 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 (where Rf) 3 (Same as the above formula (n1-2) etc.)

[0156] As other monomers mentioned above, equation (n²-1) can also be cited:

[0157] [Chemistry 3]

[0158]

[0159] (where X) 9 For H, F, or CH3; Rf 4 Fluorinated acrylate monomers, represented by fluoroalkyl groups having 1 to 40 carbon atoms or fluoroalkyl groups having ether bonds having 2 to 100 carbon atoms. The above Rf... 4 Examples of bases include:

[0160] [Chemistry 4]

[0161]

[0162] (where Z) 8 (where H, F, or Cl are used; d1 is an integer from 1 to 4; e1 is an integer from 1 to 10)

[0163] -CH(CF3)2、

[0164]

[0165] (In the formula, e2 is an integer from 1 to 5)

[0166]

[0167] (In the formula, d3 is an integer from 1 to 4; e3 is an integer from 1 to 10) etc.

[0168] As other monomers mentioned above, equation (n²-2) can also be cited:

[0169] CH2=CHO-Rf 5 (n2-2)

[0170] (where Rf) 5 Fluorinated vinyl ethers are fluorinated alkyl groups having 1 to 40 carbon atoms or fluorinated alkyl groups having ether bonds having 2 to 100 carbon atoms.

[0171] Specifically, as a monomer of the general formula (n²-2), the preferred examples are:

[0172] [Chemistry 5]

[0173]

[0174] (where Z) 9 (e4 is an integer from 1 to 10)

[0175]

[0176] (In the formula, e5 is an integer from 1 to 10)

[0177]

[0178] (In the formula, e6 is an integer from 1 to 10) etc.

[0179] More specifically, examples include:

[0180] [Chemistry 6]

[0181]

[0182] wait.

[0183] In addition, the general formula (n²-3) can be cited:

[0184] CH2=CHCH2O-Rf 6 (n2-3)

[0185] (where Rf) 6 Fluorinated allyl ethers, represented by fluoroalkyl groups having 1 to 40 carbon atoms or fluoroalkyl groups having ether bonds having 2 to 100 carbon atoms, general formula (n2-4):

[0186] CH2=CH-Rf 7 (n2-4)

[0187] (where Rf) 7 Fluorinated vinyl monomers, etc., are represented by fluorinated alkyl groups having 1 to 40 carbon atoms or fluorinated alkyl groups having ether bonds having 2 to 100 carbon atoms.

[0188] Specifically, as the monomers represented by the general formulas (n2-3) and (n2-4), examples can be given as follows:

[0189] [Chemistry 7]

[0190]

[0191] Monomers, etc.

[0192] Fluoropolymers typically have terminal groups. These terminal groups are formed during polymerization, and representative terminal groups are independently selected from hydrogen, iodine, bromine, chain-like or branched alkyl groups, and chain-like or branched fluoroalkyl groups, and may optionally contain at least one additional spurious heteroatom. The alkyl or fluoroalkyl group preferably has 1 to 20 carbon atoms. These terminal groups are typically generated by an initiator or chain transfer agent used in the formation of the fluoropolymer, or in a chain transfer reaction.

[0193] Fluoropolymers preferably have an ion exchange rate (IXR) of 53 or less. The IXR is defined as the number of carbon atoms in the polymer backbone relative to the ionic group. Precursor groups that become ionic through hydrolysis (e.g., -SO2F) are not considered ionic groups for determining the IXR.

[0194] The IXR is preferably 0.5 or more, more preferably 1 or more, further preferably 3 or more, further more preferably 4 or more, especially more preferably 5 or more, and particularly preferably 8 or more. Furthermore, the IXR is more preferably 43 or less, further preferably 33 or less, and particularly preferably 23 or less.

[0195] The preferred ion exchange capacities for fluoropolymers are, in descending order: 0.80 meq / g or higher, 1.50 meq / g or higher, 1.75 meq / g or higher, 2.00 meq / g or higher, 2.20 meq / g or higher, greater than 2.20 meq / g, 2.50 meq / g or higher, 2.60 meq / g or higher, 3.00 meq / g or higher, and 3.20 meq / g or higher. Ion exchange capacity is the content of ionic groups (anionic groups) in the fluoropolymer, calculated based on the composition of the fluoropolymer.

[0196] In fluoropolymers, ionic groups (anionic groups) are typically distributed along the polymer backbone. Fluoropolymers preferably contain a polymer backbone along with repeating side chains bonded to that backbone, and these side chains have ionic groups.

[0197] Fluoropolymers are preferably water-soluble. Water solubility refers to the property of easily dissolving or dispersing in an aqueous medium. Water-soluble fluoropolymers, for example, cannot have their particle size determined by dynamic light scattering (DLS) or show a particle size of less than 10 nm.

[0198] Fluoropolymers preferably possess sufficient water solubility. Generally, the higher the content of the fluoropolymer in the aqueous solution, the more difficult it is for the fluoropolymer to dissolve or disperse sufficiently in the aqueous medium. Therefore, even when the content of the fluoropolymer in the aqueous solution is high, it can be said that the fluoropolymer has high water solubility and cannot be determined by dynamic light scattering (DLS) particle size determination. It is preferable that the particle size of the fluoropolymer cannot be determined even when it is contained in the aqueous solution at a content of 1.0% by mass. It is even more preferable that the particle size cannot be determined even when the fluoropolymer is contained in the aqueous solution at a content of 1.5% by mass, and further preferably 2.0% by mass.

[0199] The viscosity of the aqueous solution containing the fluoropolymer is preferably 5.0 mPa·s or higher, more preferably 8.0 mPa·s or higher, even more preferably 10.0 mPa·s or higher, particularly preferably 12.0 mPa·s or higher, most preferably 14.0 mPa·s or higher, preferably 100.0 mPa·s or lower, more preferably 50.0 mPa·s or lower, even more preferably 25.0 mPa·s or lower, and particularly more preferably 20.0 mPa·s or lower.

[0200] The viscosity of an aqueous solution containing fluoropolymers can be determined by adjusting the content of the fluoropolymer in the aqueous solution to 33% by mass relative to the aqueous solution and measuring the viscosity of the aqueous solution at 20°C using a tuning fork viscometer (model: SV-10) manufactured by A&D Corporation.

[0201] The critical micelle concentration (CMC) of the fluoropolymer is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less.

[0202] The critical micelle concentration of fluoropolymers can be determined by measuring surface tension. Surface tension can be measured, for example, using a surface tension meter CBVP-A3 manufactured by Kyowa Interface Chemicals Co., Ltd.

[0203] The aqueous solution containing the fluoropolymer and the aqueous medium can be used for various applications. The content of the fluoropolymer in the aqueous solution is preferably 0.1% by mass or more, more preferably 1.0% by mass or more, further preferably 1.5% by mass or more, particularly preferably 2.0% by mass or more, particularly more preferably 5.0% by mass or more, most preferably 10% by mass or more, preferably 50% by mass or less, more preferably 40% by mass or less.

[0204] Fluoropolymers or aqueous solutions containing fluoropolymers may substantially be free of dimers and trimers of monomer (I). Dimers and trimers of monomer (I) are typically produced during the polymerization of monomer (I) to obtain the fluoropolymer. The content of dimers and trimers in the fluoropolymer is 1.0% by mass or less relative to the fluoropolymer, preferably 0.1% by mass or less, more preferably 0.01% by mass or less, further preferably 0.001% by mass or less, and particularly preferably 0.0001% by mass or less.

[0205] Fluoropolymers or aqueous solutions containing fluoropolymers may substantially be free of dimers and trimers composed of polymerization units (I) based on monomer (I) and polymerization units based on other monomers capable of copolymerizing with monomer (I). Dimers and trimers composed of polymerization units (I) and polymerization units based on other monomers are typically produced when monomer (I) and other monomers capable of copolymerizing with monomer (I) are polymerized to obtain fluoropolymers. The content of dimers and trimers composed of polymerization units (I) and polymerization units based on other monomers in the fluoropolymer is 1.0% by mass or less relative to the fluoropolymer, preferably 0.1% by mass or less, more preferably 0.01% by mass or less, further preferably 0.001% by mass or less, and particularly preferably 0.0001% by mass or less. Regarding other monomers capable of copolymerizing with monomer (I), as described above, they are, for example, monomers represented by the general formula CFR=CR2 (where R is independently H, F, or a perfluoroalkyl group having 1 to 4 carbon atoms).

[0206] The content of dimers and trimers in fluoropolymers can be determined as follows: perform gel permeation chromatography (GPC) analysis on the fluoropolymer, calculate the ratio (area percentage) of the total peak area of ​​dimers and trimers relative to the total area of ​​each peak in the chromatogram obtained by GPC analysis, and thus determine the content.

[0207] In addition, when the content of dimers and trimers in fluoropolymers is less than 0.5% by mass relative to the fluoropolymer, it can be determined by liquid chromatography-mass spectrometry (LC / MS).

[0208] Specifically, aqueous solutions of monomer (I) at five or more levels are prepared, and each concentration is analyzed by LC / MS. The relationship between the concentration and the area of ​​the region (integral value of the peak) relative to that concentration is plotted to create a calibration curve for monomer (I). Furthermore, calibration curves for the dimer and trimer of monomer (I) are created from the calibration curve of monomer (I).

[0209] A mixture was prepared by adding methanol to a fluoropolymer, filtered using an ultrafiltration disc (molecular weight cutoff 3000 Da), and the resulting recovered liquid was analyzed by LC / MS.

[0210] Then, using the calibration curve, the area (peak integral value) of the chromatogram of the dimer and trimer of monomer (I) can be converted into the content of dimer and trimer.

[0211] The content of fractions with a molecular weight of 3000 or less in fluoropolymers or aqueous solutions containing fluoropolymers may be 3.7% or less, preferably 3.2% or less, more preferably 2.7% or less, even more preferably 1.7% or less, particularly more preferably 1.2% or less, especially preferably 1.0% or less, and most preferably 0.5% or less, relative to the fluoropolymer. There is no lower limit to the content of fractions with a molecular weight of 3000 or less, for example, 0.01%. The content of fractions with a molecular weight of 3000 or less can be calculated from the peak area of ​​GPC. Fractions with a molecular weight of 3000 or less include all compounds with a molecular weight of 3000 or less.

[0212] The content of fractions with a molecular weight of 2000 or less in fluoropolymers or aqueous solutions containing fluoropolymers may be 3.2% or less, preferably 2.7% or less, more preferably 2.2% or less, even more preferably 1.7% or less, particularly more preferably 1.2% or less, and especially preferably 0.6% or less, relative to the fluoropolymer. There is no lower limit to the content of fractions with a molecular weight of 2000 or less, for example, it may be 0.01%. The content of fractions with a molecular weight of 2000 or less can be calculated from the peak area of ​​GPC. Fractions with a molecular weight of 2000 or less include all compounds with a molecular weight of 2000 or less.

[0213] The content of fractions with a molecular weight of 1500 or less in fluoropolymers or aqueous solutions containing fluoropolymers may be 2.7% or less, preferably 2.2% or less, more preferably 1.7% or less, even more preferably 1.2% or less, and particularly more preferably 0.6% or less relative to the fluoropolymer. There is no lower limit to the content of fractions with a molecular weight of 1500 or less, for example, 0.01%. The content of fractions with a molecular weight of 1500 or less can be calculated from the peak area of ​​GPC. Fractions with a molecular weight of 1500 or less include all compounds with a molecular weight of 1500 or less.

[0214] The content of fractions with a molecular weight of 1000 or less in fluoropolymers or aqueous solutions containing fluoropolymers may be 2.2% or less, preferably 1.7% or less, more preferably 1.2% or less, and even more preferably 0.6% or less relative to the fluoropolymer. There is no lower limit to the content of fractions with a molecular weight of 1000 or less, for example, 0.01%. The content of fractions with a molecular weight of 1000 or less can be calculated from the peak area of ​​GPC. Fractions with a molecular weight of 1000 or less include all compounds with a molecular weight of 1000 or less.

[0215] The fluoropolymer or aqueous solution containing the fluoropolymer preferably does not contain fluorinated surfactants. In this disclosure, "substantially does not contain fluorinated surfactants" means that the content of fluorinated surfactants in the fluoropolymer or aqueous solution is less than 10 ppm by mass, preferably less than 1 ppm by mass, more preferably less than 100 ppb by mass, further preferably less than 10 ppb by mass, even more preferably less than 1 ppb by mass, and particularly preferably less than the detection limit of the fluorinated surfactants determined by liquid chromatography-mass spectrometry (LC / MS).

[0216] The content of fluorinated surfactants can be quantified using known methods. For example, LC / MS analysis can be used for quantification.

[0217] First, methanol is added to the fluoropolymer or aqueous solution for extraction, and the resulting extract is analyzed by LC / MS. To further improve extraction efficiency, treatments such as Soxhlet extraction and ultrasonic treatment can be performed.

[0218] Based on the obtained LC / MS mass spectra, molecular weight information was selected to confirm the consistency with the structural formula of the candidate fluorinated surfactant.

[0219] Subsequently, for the confirmed fluorinated surfactant, aqueous solutions with concentrations of more than 5 levels were prepared, and LC / MS analysis was performed on the aqueous solutions with each concentration. The relationship between the concentration and the area of ​​the region relative to that concentration was plotted, and a calibration curve was drawn.

[0220] Subsequently, using a calibration curve, the area of ​​the LC / MS chromatogram of the fluorinated surfactant in the extract can be converted into the content of the fluorinated surfactant.

[0221] The following section provides an explanation of the polymerization of fluorinated surfactants with monomer (I).

[0222] Fluoropolymers or aqueous solutions containing fluoropolymers can be used for a variety of applications. Fluoropolymers or aqueous solutions containing fluoropolymers can be suitably used as components, for example, in coating compositions.

[0223] The coating composition is preferably a composition consisting of a fluoropolymer and at least one solvent selected from the group consisting of water and alcohol. By using such a coating composition, a coating film exhibiting excellent anti-reflective properties can be formed. By using a coating composition containing a fluoropolymer with a large amount of polymeric units (I), a uniform coating film with the desired film thickness can be easily formed, and the anti-reflective properties and hydrophilicity of the resulting coating film can be improved, resulting in sufficient developer dissolution rate. Furthermore, the higher the content of polymeric units (I) in the fluoropolymer, the lower the refractive index and the better the developer solubility of the coating film, which is therefore preferred.

[0224] The solvent contained in the coating composition is at least one selected from the group consisting of water and alcohol. As an alcohol, a lower alcohol having 1 to 6 carbon atoms is preferred, and at least one selected from the group consisting of methanol, ethanol, isopropanol, n-propanol and butanol is more preferred.

[0225] The coating composition may further contain a water-soluble organic solvent (excluding alcohols), at least one alkaline substance selected from ammonia or organic amines, a surfactant, an acid, a water-soluble polymer, a photoacid generator, a defoamer, a light absorber, a preservation stabilizer, a preservative, an adhesive aid, a dye, etc.

[0226] The content of the fluoropolymer in the coating composition is preferably 0.1 to 50% by mass, more preferably 0.5 to 30% by mass, further preferably 1 to 20% by mass, and particularly preferably 2 to 10% by mass relative to the coating composition.

[0227] A coated film can be made by applying a coating composition to a substrate. There are no particular limitations on the coating method, and methods such as roller coating, casting, dipping, spin coating, water casting, mold coating, and Langmuir-Blodgett method can be cited.

[0228] Examples of substrates to which the coating composition is applied include silicon wafers and quartz glass.

[0229] Especially when strict film thickness control is required, spin coating is suitable. When using spin coating, the film thickness depends on the substrate rotation speed, spin time, and viscosity of the coating composition. Regarding the characteristics of the equipment (spin coater), if the rotation speed is too slow or the spin time is too short, uneven film thickness can easily occur. Therefore, high rotation speeds and a certain amount of time are typically used for coating.

[0230] However, when the coating composition is coated at a high rotation speed and for a certain period of time, the resulting film thickness decreases. Therefore, it is not easy to produce a relatively thick film while suppressing film thickness unevenness using spin coating. The coating composition disclosed herein, in addition to containing a fluoropolymer with a large number of polymeric units (I), can form a coating film with uniform film thickness even when containing a high concentration of fluoropolymer. Therefore, it can impart excellent effects such as hydrophilicity to the coating film, and can easily produce a relatively thick film while suppressing film thickness unevenness.

[0231] The coated film obtained from the coating composition is suitable as, for example, a surface film or an anti-reflective film. For example, by coating the coating composition onto a photoresist layer, a photoresist laminate having a photoresist layer and an anti-reflective film can be produced.

[0232] The fluoropolymer disclosed herein can be manufactured by a method for manufacturing a fluoropolymer of monomer (I) by polymerizing monomer (I).

[0233] From the perspective of easily manufacturing fluoropolymers with higher molecular weights, the oxygen concentration in the polymerization reaction system is preferably 1500 ppm by volume or less, more preferably 500 ppm by volume or less, even more preferably 100 ppm by volume or less, and particularly preferably 50 ppm by volume or less. Furthermore, the oxygen concentration in the reaction system is typically 0.01 ppm by volume or more. In the above-described manufacturing method, it is preferable that the oxygen concentration in the reaction system is maintained within the above-described range throughout the polymerization of monomer (I).

[0234] The oxygen concentration in a polymerization reaction system can be controlled, for example, by introducing inert gases such as nitrogen or argon, or, in the case of gaseous monomers, by allowing the gaseous monomers to flow into the liquid or gas phase of the reactor. The oxygen concentration in the polymerization reaction system can also be determined by measuring and analyzing the gas discharged from the polymerization system's exhaust line using a low-concentration oxygen analyzer.

[0235] For the purpose of easily producing fluoropolymers with higher molecular weights, the polymerization temperature of monomer (I) is preferably below 80°C, preferably below 70°C, more preferably below 65°C, even more preferably below 60°C, even more preferably below 55°C, even more preferably below 50°C, particularly preferably below 45°C, most preferably below 40°C, preferably above 10°C, more preferably above 15°C, and even more preferably above 20°C.

[0236] In the above manufacturing method, monomer (I) can be copolymerized with the other monomers mentioned above.

[0237] In the above manufacturing method, polymerization can be carried out in the presence of a pH adjuster. The pH adjuster can be added before or after polymerization begins.

[0238] Ammonia, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, ammonium carbonate, sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, sodium phosphate, potassium phosphate, sodium citrate, potassium citrate, ammonium citrate, sodium gluconate, potassium gluconate, and ammonium gluconate can be used as pH adjusters. The pH values ​​mentioned above can be measured using a pH meter manufactured by Orion.

[0239] Polymerization pressure is typically atmospheric pressure to 10 MPaG. The polymerization pressure is appropriately determined based on the type of monomer used, the molecular weight of the target fluoropolymer, and the reaction rate.

[0240] The polymerization time is usually 1 to 200 hours, but can also be 5 to 100 hours.

[0241] In the above manufacturing method, the polymerization of monomer (I) can be carried out in an aqueous medium or in the absence of an aqueous medium. Alternatively, the polymerization of monomer (I) can be carried out in the absence of an aqueous medium, i.e., in the presence of a non-aqueous medium (e.g., an organic solvent such as toluene) in the presence of less than 10% by mass of the monomer containing monomer (I). The polymerization of monomer (I) can be emulsion polymerization, suspension polymerization, or bulk polymerization.

[0242] Aqueous medium refers to a water-containing liquid that serves as the reaction medium for polymerization. There are no particular limitations on the aqueous medium as long as it contains water; it can contain water, as well as non-fluorinated organic solvents such as alcohols, ethers, and ketones, and / or fluorinated organic solvents with a boiling point below 40°C. Water is preferred as the aqueous medium.

[0243] In the above manufacturing method, the polymerization of monomer (I) can be carried out in the presence of a polymerization initiator. As the polymerization initiator, there are no particular limitations as long as free radicals can be generated within the above-mentioned polymerization temperature range; known oil-soluble and / or water-soluble polymerization initiators can be used. Furthermore, polymerization can be initiated in a redox manner by combining it with a reducing agent, etc. The concentration of the polymerization initiator is appropriately determined according to the type of monomer, the molecular weight of the target fluoropolymer, and the reaction rate. When the polymerization of monomer (I) is carried out in an aqueous medium, a water-soluble polymerization initiator such as persulfate is preferred. When the polymerization of monomer (I) is carried out in the absence of an aqueous medium, an oil-soluble polymerization initiator such as peroxide is preferred.

[0244] As polymerization initiators, organic peroxides such as persulfates (e.g., ammonium persulfate), disuccinic acid peroxide, and diglutaric acid peroxide can be used alone or in mixtures thereof. Alternatively, they can be used in conjunction with reducing agents such as sodium sulfite to create a redox system. Furthermore, free radical scavengers such as hydroquinone and catechol, or peroxide decomposers such as ammonium sulfite, can be added to adjust the free radical concentration within the system during polymerization.

[0245] As a polymerization initiator, persulfate is preferred because it facilitates the production of fluoropolymers with higher molecular weights. Examples of persulfates include ammonium persulfate, potassium persulfate, and sodium persulfate, with ammonium persulfate being the most preferred.

[0246] Oil-soluble free radical polymerization initiators can be used as polymerization initiators. Known oil-soluble peroxides can be used as oil-soluble free radical polymerization initiators, such as the following representative peroxides: diisopropyl peroxide, disec-butyl peroxide, and other dialkyl peroxide esters; tert-butyl peroxide, tert-butyl peroxyisobutyrate, and other peroxide esters; dialkyl peroxides such as di-tert-butyl peroxide; and bis(ω-hydro-dodecylfluorohexanoyl) peroxide, bis(ω-hydro-tetradecylfluoroheptanoyl) peroxide, bis(ω-hydro-hexadecylfluorononanoyl) peroxide, bis(perfluorobutyryl) peroxide, bis(perfluoropentanoyl) peroxide, bis(perfluorohexanoyl) peroxide, bis(perfluoroheptanoyl) peroxide, bis(perfluorooctanoyl) peroxide, bis(perfluorooctanoyl) peroxide, etc. Oxides, di(perfluorononanoyl) peroxides, di(ω-chloro-hexafluorobutyryl) peroxides, di(ω-chloro-decafluorohexanoyl) peroxides, di(ω-chloro-tetrafluorooctanoyl) peroxides, ω-hydro-dodecanoyl-ω-hydrohexafluorononanoyl-peroxides, ω-chloro-hexafluorobutyryl-ω-chloro-decafluorohexanoyl-peroxides, ω-hydro-dodecanoyl-perfluorobutyryl-peroxides, di(dichloropentafluorobutyryl) peroxides, di(trichlorooctafluorohexanoyl) peroxides, di(tetrachloroundecanoyl) peroxides, di(pentachlorotetrafluorodecanoyl) peroxides, di(undecanoyltridodecanoyl)fluoroethoacyl) peroxides, etc., are all di[perfluoro(or fluorochloro)acyl] peroxides; etc.

[0247] There is no particular limitation on the amount of polymerization initiator added. It is acceptable to add an amount (e.g., a concentration of several ppm relative to water) that will not significantly reduce the polymerization rate when added once, gradually, or continuously at the beginning of polymerization. The upper limit is the range in which the heat of polymerization can be deheated from the surface of the equipment while increasing the reaction temperature. More preferably, the upper limit is the range in which the heat of polymerization can be removed from the surface of the equipment.

[0248] In the above manufacturing method, the polymerization initiator can be added at the beginning of polymerization and also during polymerization. The ratio of the amount of polymerization initiator added at the beginning of polymerization to the amount of polymerization initiator added during polymerization is preferably 95 / 5 to 5 / 95, more preferably 60 / 40 to 10 / 90, and even more preferably 30 / 70 to 15 / 85. The method of adding the polymerization initiator during polymerization is not particularly limited; it can be added all at once, added in two or more installments, or added continuously.

[0249] In the above manufacturing method, for the purpose of easily manufacturing fluoropolymers with higher molecular weights, the total amount of polymerization initiator added relative to the aqueous medium is preferably 0.00001 to 10% by mass. The total amount of polymerization initiator added is preferably 0.0001% by mass or more, more preferably 0.001% by mass or more, further preferably 0.01% by mass or more, preferably 5% by mass or less, and more preferably 2% by mass or less.

[0250] In the above manufacturing method, for the purpose of easily manufacturing fluoropolymers with higher molecular weights, the total amount of polymerization initiator added in the polymerization is preferably 0.001 to 10 mol% relative to the total amount of monomers added in the polymerization. The total amount of polymerization initiator added in the polymerization is more preferably 0.005 mol% or more, further preferably 0.01 mol% or more, particularly more preferably 0.1 mol% or more, most preferably 0.5 mol% or more, more preferably 10 mol% or less, further preferably 5.0 mol% or less, particularly more preferably 2.5 mol% or less, particularly most preferably 2.2 mol% or less, and preferably 2.0 mol% or less.

[0251] In the above-described manufacturing method, for the purpose of easily manufacturing fluoropolymers with higher molecular weights, the amount of monomer (I) present at the start of polymerization is preferably 20% by mass or more relative to the amount of aqueous medium. More preferably, the amount of monomer is 30% by mass or more, and even more preferably 40% by mass or more. There is no particular upper limit to the amount of monomer; from the perspective of smoothly carrying out polymerization, it can be 200% by mass or less. The amount of monomer present at the start of polymerization refers to the total amount of monomer (I) present in the reactor at the start of polymerization, plus any other monomers present if other monomers are present.

[0252] When polymerization of monomer (I) is carried out in the absence of an aqueous medium, the total amount of polymerization initiator such as peroxide added is preferably 0.001 to 10 mol% relative to the total amount of monomer (monomer mixture) containing monomer (I). The total amount of polymerization initiator added for polymerization is more preferably 0.005 mol% or more, further preferably 0.01 mol% or more, more preferably 10 mol% or less, further preferably 5.0 mol% or less, particularly more preferably 2.5 mol% or less, especially most preferably 2.2 mol% or less, and preferably 2.0 mol% or less.

[0253] The polymerization of monomer (I) can be carried out as follows: an aqueous medium, monomer (I), and other monomers and additives, if necessary, are added to a reactor; the contents of the reactor are stirred, and the reactor is maintained at a specified polymerization temperature; then a specified amount of polymerization initiator is added to initiate the polymerization reaction, thereby carrying out polymerization. After the polymerization reaction begins, monomers, polymerization initiators, and other additives may be added according to the purpose.

[0254] The polymerization of monomer (I) can be carried out in the substantially absence of a fluorinated surfactant. In this disclosure, "in the substantially absence of a fluorinated surfactant" means that the amount of the fluorinated surfactant relative to the aqueous medium is 10 ppm by mass or less. The amount of the fluorinated surfactant relative to the aqueous medium is preferably 1 ppm by mass or less, more preferably 100 ppb by mass or less, even more preferably 10 ppb by mass or less, and even more preferably 1 ppb by mass or less.

[0255] Examples of fluorinated surfactants include anionic fluorinated surfactants. For instance, anionic fluorinated surfactants may contain fluorine atoms and have a total carbon number of 20 or less in the portion excluding the anionic group.

[0256] The aforementioned fluorinated surfactant may also be a fluorinated surfactant with an anionic moiety having a molecular weight of 1000 or less, preferably 800 or less.

[0257] It should be noted that the "anionic portion" mentioned above refers to the portion of the fluorinated surfactant other than the cationic portion. For example, F(CF2) represented by formula (I) described later. n1 In the case of COOM, it is "F(CF2)". n1 The "COO" part.

[0258] As examples of the aforementioned fluorinated surfactants, fluorinated surfactants with a LogPOW of 3.5 or less can also be cited. The aforementioned LogPOW is the partition coefficient of 1-octanol and water, which is represented by LogP [where P represents the ratio of the concentration of the fluorinated surfactant in octanol to the concentration of the fluorinated surfactant in water when phase separation occurs in the octanol / water (1:1) mixture containing the fluorinated surfactant].

[0259] The above LogPOW is calculated as follows: In column: TOSOH ODS-120T column ( Under the following conditions: (manufactured by Tosoh Corporation), eluent: acetonitrile / 0.6% HClO4 water = 1 / 1 (vol / vol%), flow rate: 1.0 ml / min, sample volume: 300 μL, column temperature: 40 °C, detection light: UV210 nm, HPLC was performed on standard substances (heptaneic acid, octanoic acid, nonanoic acid, and decanoic acid) with known octanol / water partition coefficients. Calibration curves were prepared for each elution time and the known octanol / water partition coefficients. Based on these calibration curves, the elution time in the sample solution was calculated according to the HPLC elution time.

[0260] Specifically, examples of the aforementioned fluorinated surfactants include U.S. Patent Application Publication No. 2007 / 0015864, U.S. Patent Application Publication No. 2007 / 0015865, U.S. Patent Application Publication No. 2007 / 0015866, U.S. Patent Application Publication No. 2007 / 0276103, U.S. Patent Application Publication No. 2007 / 0117914, U.S. Patent Application Publication No. 2007 / 142541, U.S. Patent Application Publication No. 2008 / 0015319, and U.S. Patent No. 3250808. Fluorinated surfactants described in U.S. Patent No. 3,271,341, Japanese Patent Application Publication No. 2003-119204, International Publication No. 2005 / 042593, International Publication No. 2008 / 060461, International Publication No. 2007 / 046377, Japanese Patent Application Publication No. 2007-119526, International Publication No. 2007 / 046482, International Publication No. 2007 / 046345, U.S. Patent Application Publication No. 2014 / 0228531, International Publication No. 2013 / 189824, and International Publication No. 2013 / 189826, etc.

[0261] Examples of anionic fluorinated surfactants include those with the following general formula (N 0 ):

[0262] X n0 -Rf n0 -Y 0 (N 0)

[0263] (where X) n0 For H, Cl, and / or F. Rf n0 Y is a chain-like, branched, or cyclic alkylene group with 3 to 20 carbon atoms, in which some or all of the H atoms are replaced by F. This alkylene group may contain more than one ether bond, and some of the H atoms may be replaced by Cl. 0 Compounds represented by anionic groups.

[0264] Y 0 The anionic group can be -COOM, -SO2M or -SO3M, or it can be -COOM or -SO3M.

[0265] M represents H, a metal atom, and NR. 7 4. Imidazolium with or without substituents, pyridinium with or without substituents, or phosphonium with or without substituents, R 7 It is an H or an organic group.

[0266] Examples of metal atoms mentioned above include alkali metals (Group 1) and alkaline earth metals (Group 2), such as Na, K, or Li.

[0267] As R 7 It can be H or C 1-10 The organic group can also be H or C. 1-4 The organic groups can also be H or C. 1-4 Alkyl groups.

[0268] M can be H, a metal atom, or NR. 7 4, can also be H, alkali metals (Group 1), alkaline earth metals (Group 2), or NR. 7 4. It can also be H, Na, K, Li or NH4.

[0269] The above Rf n0 In this process, more than 50% of H can be replaced by fluorine.

[0270] As the above general formula (N) 0 The compounds represented by ) can be listed as follows:

[0271] The following general formula (N) 1 ):

[0272] X n0 -(CF2) m1 -Y 0 (N 1 )

[0273] (where X) n0 H, Cl, and F are given, m1 is an integer from 3 to 15, and Y is given. 0Compounds represented by the groups defined above; compounds of the following general formula (N 2 ):

[0274] Rf n1 -O-(CF(CF3)CF2O) m2 CFX n1 -Y 0 (N 2 )

[0275] (where Rf) n1 It is a perfluoroalkyl group with 1 to 5 carbon atoms, m2 is an integer from 0 to 3, and X n1 For F or CF3, Y 0 Compounds represented by the groups defined above; compounds of the following general formula (N 3 ):

[0276] Rf n2 (CH2) m3 -(Rf n3 ) q -Y 0 (N 3 )

[0277] (where Rf) n2 It is an alkyl group with 1 to 13 carbon atoms, which may contain ether bonds or be partially or fully fluorinated, m3 is an integer from 1 to 3, and Rf n3 It is a straight-chain or branched perfluoroalkylene group with 1 to 3 carbon atoms, where q is 0 or 1, and Y is... 0 Compounds represented by the groups defined above; compounds of the following general formula (N 4 ):

[0278] Rf n4 -O-(CY n1 Y n2 ) p CF2-Y 0 (N 4 )

[0279] (where Rf) n4 Y is a straight-chain or branched partially or fully fluorinated alkyl group having 1 to 12 carbon atoms and may contain ether bonds and / or chlorine atoms. n1 and Y n2 Same or different, H or F, p is 0 or 1, Y 0 Compounds represented by the groups defined above; and compounds of the general formula (N 5 ):

[0280] [Chemistry 8]

[0281]

[0282] (where X) n2 X n3 and X n4 They can be the same or different, and can be H, F, or a straight-chain or branched partially or fully fluorinated alkyl group having 1 to 6 carbon atoms and containing ether bonds. Rf n5 It is a linear or branched partially or fully fluorinated alkylene group with 1 to 3 carbon atoms, which may contain ether bonds, where L is a linking group and Y is a linking group. 0 This refers to the group defined above. Where X... n2 X n3 X n4 and Rf n5 Compounds whose total number of carbon atoms is 18 or less.

[0283] As the above general formula (N) 0 The compounds represented by the formula (I) can be more specifically exemplified by perfluorocarboxylic acids (I) represented by the general formula (II), ω-H perfluorocarboxylic acids (II) represented by the general formula (III), perfluoroether carboxylic acids (III), perfluoroalkylalkylene carboxylic acids (IV) represented by the general formula (IV), perfluoroalkoxyfluorocarboxylic acids (V) represented by the general formula (V), perfluoroalkylsulfonic acids (VI) represented by the general formula (VI), ω-H perfluorosulfonic acids (VII) represented by the general formula (VII), perfluoroalkylalkylene sulfonic acids (VIII) represented by the general formula (VIII), alkylalkylene carboxylic acids (IX) represented by the general formula (IX), fluorocarboxylic acids (X) represented by the general formula (X), alkoxyfluorosulfonic acids (XI) represented by the general formula (XI), compounds represented by the general formula (XII), and compounds represented by the general formula (XIII).

[0284] The above-mentioned perfluorocarboxylic acid (I) is derived from the following general formula (I).

[0285] F(CF2) n1 COOM(I)

[0286] (In the formula, n1 is an integer from 3 to 14, M is H, metal atom, NR) 7 4. Imidazolium with or without substituents, pyridinium with or without substituents, or phosphonium with or without substituents, R 7 It is represented by H or an organic group.

[0287] The above-mentioned ω-H perfluorocarboxylic acids (II) are derived from the following general formula (II).

[0288] H(CF2) n2 COOM(II)

[0289] (where n2 is an integer from 4 to 15, and M is a group defined above.)

[0290] The above-mentioned perfluoroether carboxylic acid (III) is derived from the following general formula (III).

[0291] Rf 1 -O-(CF(CF3)CF2O) n3 CF(CF3)COOM(III)

[0292] (where Rf) 1 It is represented by a perfluoroalkyl group having 1 to 5 carbon atoms, n3 being an integer from 0 to 3, and M being a group defined above.

[0293] The above-mentioned perfluoroalkylalkylene carboxylic acids (IV) are derived from the following general formula (IV).

[0294] Rf 2 (CH2) n4 Rf 3 COOM(IV)

[0295] (where Rf) 2 It is a perfluoroalkyl group with 1 to 5 carbon atoms, Rf 3 It is represented by a perfluoroalkylene group with 1 to 3 carbon atoms (where n4 is an integer from 1 to 3, and M is a group defined above).

[0296] The above-mentioned alkoxyfluorocarboxylic acid (V) is derived from the following general formula (V).

[0297] Rf 4 -O-CY 1 Y 2 CF2-COOM(V)

[0298] (where Rf) 4 Y is a straight-chain or branched partially or fully fluorinated alkyl group having 1 to 12 carbon atoms and may contain ether bonds and / or chlorine atoms. 1 and Y 2 The same or different (H or F, M is a group defined above) are represented by this.

[0299] The above-mentioned perfluoroalkyl sulfonic acid (VI) is produced by the following general formula (VI).

[0300] F(CF2) n5 SO3M(VI)

[0301] (where n5 is an integer from 3 to 14, and M is a group defined above.)

[0302] The above-mentioned ω-H perfluorosulfonic acid (VII) is derived from the following general formula (VII).

[0303] H(CF2) n6 SO3M(VII)

[0304] (where n6 is an integer from 4 to 14, and M is a group defined above.)

[0305] The above-mentioned perfluoroalkyl alkylene sulfonic acid (VIII) is produced by the following general formula (VIII).

[0306] Rf 5 (CH2) n7 SO3M(VIII)

[0307] (where Rf) 5 It is represented by a perfluoroalkyl group having 1 to 13 carbon atoms, n7 being an integer from 1 to 3, and M being a group defined above.

[0308] The above-mentioned alkylalkylene carboxylic acids (IX) are derived from the following general formula (IX).

[0309] Rf 6 (CH2) n8 COOM(IX)

[0310] (where Rf) 6 It is represented by a straight-chain or branched partially or fully fluorinated alkyl group with 1 to 13 carbon atoms that may contain ether bonds, where n8 is an integer from 1 to 3 and M is a group defined above.

[0311] The above-mentioned fluorocarboxylic acid (X) is derived from the following general formula (X).

[0312] Rf 7 -O-Rf 8 -O-CF2-COOM(X)

[0313] (where Rf) 7 Rf is a straight-chain or branched partially or fully fluorinated alkyl group having 1 to 6 carbon atoms and may contain ether bonds and / or chlorine atoms. 8 It is represented by a straight-chain or branched partially or fully fluorinated alkyl group having 1 to 6 carbon atoms, where M is a group defined above.

[0314] The above-mentioned alkoxyfluorosulfonic acid (XI) is derived from the following general formula (XI).

[0315] Rf 9 -O-CY 1 Y 2 CF2-SO3M(XI)

[0316] (where Rf) 9 Y is a straight-chain or branched alkyl group with 1 to 12 carbon atoms, which may contain ether bonds and may be partially or fully fluorinated, and may contain chlorine. 1and Y 2 The same or different (H or F, M is a group defined above) are represented by this.

[0317] The above compound (XII) is derived from the following general formula (XII):

[0318] [Chemistry 9]

[0319]

[0320] (where X) 1 X 2 and X 3 They can be the same or different, and are H, F, and linear or branched partially or fully fluorinated alkyl groups containing ether bonds, with 1 to 6 carbon atoms; Rf 10 It is a perfluoroalkylene group with 1 to 3 carbon atoms, where L is a linking group and Y is a carbon atom group. 0 It is represented by an anionic group.

[0321] Y 0 It can be -COOM, -SO2M or -SO3M, or -SO3M or COOM (where M is a group defined above).

[0322] Examples of L include single bonds, partially or fully fluorinated alkylene groups with 1 to 10 carbon atoms that may contain ether bonds.

[0323] The above compound (XIII) is derived from the following general formula (XIII):

[0324] Rf 11 -O-(CF2CF(CF3)O) n9 (CF2O) n10 CF2COOM(XIII)

[0325] (where Rf) 11 The compound (XIII) is represented by a fluoroalkyl group containing chlorine with 1 to 5 carbon atoms, where n9 is an integer from 0 to 3, n10 is an integer from 0 to 3, and M is a group defined above. As a compound (XIII), it is CF2ClO (CF2CF(CF3)O). n9 (CF2O) n10 CF2COONH4 (a mixture with an average molecular weight of 750, where n9 and n10 are groups defined above).

[0326] As mentioned above, examples of anionic fluorinated surfactants include carboxylic acid surfactants and sulfonic acid surfactants.

[0327] Fluorinated surfactants can be a single fluorinated surfactant or a mixture containing two or more fluorinated surfactants.

[0328] Examples of fluorinated surfactants include compounds represented by the following formula. Fluorinated surfactants can also be mixtures of these compounds. In one embodiment of the above polymerization, monomer (I) is polymerized in the absence of the compound represented by the following formula.

[0329] F(CF2)7COOM、

[0330] F(CF2)5COOM,

[0331] H(CF2)6COOM,

[0332] H(CF2)7COOM,

[0333] CF3O(CF2)3OCHFCF2COOM,

[0334] C3F7OCF(CF3)CF2OCF(CF3)COOM,

[0335] CF3CF2CF2OCF(CF3)COOM,

[0336] CF3CF2OCF2CF2OCF2COOM,

[0337] C2F5OCF(CF3)CF2OCF(CF3)COOM,

[0338] CF3OCF(CF3)CF2OCF(CF3)COOM,

[0339] CF2ClCF2CF2OCF(CF3)CF2OCF2COOM,

[0340] CF2ClCF2CF2OCF2CF(CF3)OCF2COOM,

[0341] CF2ClCF(CF3)OCF(CF3)CF2OCF2COOM,

[0342] CF2ClCF(CF3)OCF2CF(CF3)OCF2COOM,

[0343] [Chemistry 10]

[0344]

[0345] (In each formula, M represents H, a metal atom, and NR) 7 4. Imidazolium with or without substituents, pyridinium with or without substituents, or phosphonium with or without substituents, R 7 (It is an H group or an organic group.)

[0346] In the above manufacturing method, since the polymerization of monomer (I) is carried out in an aqueous medium, an aqueous solution containing a fluoropolymer and an aqueous medium is usually obtained. The resulting aqueous solution containing the fluoropolymer can be used directly for various applications, or the fluoropolymer obtained by separation from the aqueous solution can be used for various applications. There are no particular limitations on the method for separating the fluoropolymer from the aqueous solution. For example, the fluoropolymer can be separated by methods such as precipitation, washing, and drying of the fluoropolymer in the aqueous solution.

[0347] Fluoropolymers or aqueous solutions obtained by polymerization of monomer (I) contain fractions with a molecular weight of less than 3000, less than 2000, less than 1500, less than 1000, dimers and trimers of monomer (I), etc. To remove these components, the fluoropolymers or aqueous solutions obtained by polymerization of monomer (I) can be post-treated.

[0348] For example, in the above manufacturing method, the composition containing an aqueous medium and a fluoropolymer can be recovered after the polymerization of monomer (I) is completed, and the obtained composition can be treated by at least one means selected from the group consisting of ultrafiltration, microfiltration, dialysis membrane treatment, separation and reprecipitation.

[0349] When the polymerization of monomer (I) is carried out in the absence of an aqueous medium, a fluoropolymer or a composition containing a fluoropolymer is obtained after the polymerization is completed. Therefore, the fluoropolymer or the composition can be mixed with an aqueous medium, and the resulting composition containing an aqueous medium and a fluoropolymer can be treated by at least one means selected from the group consisting of ultrafiltration, microfiltration, dialysis membrane treatment, separation and reprecipitation.

[0350] In the composition obtained by polymerizing monomer (I), dimers and trimers typically comprise a total of more than 1.0% by mass relative to the mass of the fluoropolymer of monomer (I). The content of dimers and trimers may, for example, be more than 2.0% by mass, more than 3.0% by mass, less than 30.0% by mass, or less than 20.0% by mass relative to the fluoropolymer of monomer (I).

[0351] Furthermore, the composition obtained by polymerizing monomer (I) and other monomers capable of copolymerizing with monomer (I) typically contains dimers and trimers composed of monomer-based polymerization units (I) and polymerization units based on other monomers capable of copolymerizing with monomer (I), in an amount greater than 1.0% by mass relative to the total mass of the fluoropolymer. The content of dimers and trimers composed of polymerization units (I) and polymerization units based on other monomers can, for example, be 2.0% by mass or more, 3.0% by mass or more, 30.0% by mass or less, or 20.0% by mass or less relative to the fluoropolymer.

[0352] The content of dimers and trimers in the composition can be determined as follows: gel permeation chromatography (GPC) analysis of the composition is performed, and the total peak area of ​​dimers and trimers relative to the total peak area of ​​the chromatogram obtained by GPC analysis is calculated as a percentage (area percentage), thereby determining the content.

[0353] Next, the obtained composition containing the aqueous medium and the fluoropolymer is preferably recovered by treating the composition using at least one means selected from the group consisting of ultrafiltration, microfiltration, dialysis membrane treatment, separation, and reprecipitation. This treatment removes dimers and trimers of monomer (I) contained in the composition obtained by polymerization of monomer (I), or dimers and trimers composed of polymerization units (I) and polymerization units based on other monomers. As a treatment means, at least one means selected from the group consisting of ultrafiltration, microfiltration, separation, and reprecipitation is more preferred; at least one means selected from the group consisting of ultrafiltration and separation is even more preferred; ultrafiltration is particularly preferred.

[0354] The polymerization of monomer (I) produces dimers and trimers of monomer (I), resulting in the presence of dimers and trimers of monomer (I) in fluoropolymers. The formation mechanism of dimers and trimers of monomer (I) is not necessarily clear, but it is speculated that, particularly in monomers present in the polymerization system, dimers and trimers of monomer (I) are produced at a non-negligible frequency through polymerization reactions in polymerization systems where monomer (I) constitutes the majority.

[0355] When removing dimers and trimers, unreacted monomers (I) are usually also removed from the composition. Furthermore, by appropriately selecting post-treatment methods, fractions with a molecular weight of 3000 or less, 2000 or less, 1500 or less, and 1000 or less can also be removed.

[0356] The composition obtained by polymerization of monomer (I) can be a fully polymerized composition obtained during polymerization, a substance obtained by diluting or concentrating a fully polymerized composition obtained during polymerization, or a substance that has undergone dispersion stabilization treatment, etc. In order to facilitate ultrafiltration, microfiltration, or dialysis membrane treatment, it is also preferable to adjust the viscosity of the composition through these treatments.

[0357] The content of the fluoropolymer in monomer (I) of the composition is not particularly limited, and can be, for example, from 0.1% to 40.0% by mass. From the perspective of the removal efficiency of dimers and trimers, the content of the fluoropolymer in the composition is preferably 30.0% by mass or less, more preferably 25.0% by mass or less, further preferably 20.0% by mass or less, particularly preferably 10.0% by mass or less, preferably 0.5% by mass or more, more preferably 1.0% by mass or more, further preferably 1.2% by mass or more, and particularly preferably 1.5% by mass or more. The content of the fluoropolymer in the composition can be adjusted, for example, by adding water to the composition obtained by polymerization of monomer (I), or by concentrating the composition obtained by polymerization of monomer (I).

[0358] The pH of the composition is preferably -7.0 to 11.0, more preferably -6.0 to 8.0, and even more preferably -5.0 to 7.0. The pH of the composition can be adjusted by adding a pH adjuster to the composition obtained by polymerization of monomer (I). The pH adjuster can be an acid or a base, such as phosphates, sodium hydroxide, potassium hydroxide, ammonia, etc.

[0359] When performing ultrafiltration, microfiltration, or dialysis membrane treatment, the viscosity of the composition is preferably 25 mPa·s or less for the smooth execution of these treatments. The viscosity of the composition can be adjusted, for example, by adjusting the weight-average molecular weight and number-average molecular weight of the fluoropolymer, adjusting the concentration of the fluoropolymer in the composition, or adjusting the temperature of the composition.

[0360] The ultrafiltration or microfiltration described above can be either cross-flow or dead-end, without limitation. From the perspective of reducing membrane clogging, cross-flow is preferred.

[0361] The above-mentioned ultrafiltration can be performed using an ultrafiltration membrane. Ultrafiltration can be performed, for example, using an ultrafiltration device equipped with an ultrafiltration membrane, and can employ centrifugal ultrafiltration, intermittent ultrafiltration, circulating ultrafiltration, etc.

[0362] The molecular weight cutoff of the aforementioned ultrafiltration membranes is typically 0.1 × 10⁻⁶. 4 ~30×10 4Approximately 0.3 × 10⁻⁶ m³ / s. To suppress membrane clogging and effectively reduce dimers and trimers, the preferred molecular weight cutoff of the aforementioned ultrafiltration membrane is 0.3 × 10⁻⁶ m³ / s. 4 The molecular weight cutoff is more preferably 0.5 × 10⁻⁶. 4 Da or higher, with a preferred value of 0.6 × 10⁻⁶. 4 Da or higher, the optimal value is 0.8 × 10⁻⁶. 4 The molecular weight cutoff is above 1.0 × 10⁻⁶. 4 Above Da. Furthermore, considering the removal efficiency of dimers and trimers, the aforementioned molecular weight cutoff is preferably 20 × 10⁻⁶. 4 Da or less, more preferably 10×10 4 The following is a summary of the above.

[0363] Regarding the molecular weight cutoff of the aforementioned ultrafiltration membrane, for example, polystyrene with a known weight-average molecular weight can pass through the membrane, and 90% of the molecular weights will be blocked as the cutoff molecular weight. The quantification of polystyrene can be performed using gel permeation chromatography.

[0364] As for the shape of the ultrafiltration membrane, there are existing and known shapes that can be cited, but there is no limitation. Examples include hollow fiber type, flat membrane type, spiral type, and tubular type. From the perspective of suppressing clogging, hollow fiber type is preferred.

[0365] The inner diameter of the hollow fiber ultrafiltration membrane is not limited, and can be, for example, 0.1 to 2 mm. Preferably, it is 0.8 to 1.4 mm.

[0366] The length of the hollow fiber ultrafiltration membrane is not limited, and can be, for example, 0.05 to 3 m. Preferably, it is 0.05 to 2 m.

[0367] There are no particular limitations on the materials used for ultrafiltration membranes. Examples include organic materials such as cellulose, cellulose esters, polysulfone, sulfonated polysulfone, polyethersulfone, sulfonated polyethersulfone, chlorinated polyethylene, polypropylene, polyolefins, polyvinyl alcohol, polymethyl methacrylate, polyacrylonitrile, polyvinylidene fluoride, and polytetrafluoroethylene, as well as metals such as stainless steel and inorganic materials such as ceramics.

[0368] The material of the ultrafiltration membrane is preferably an organic material, more preferably chlorinated polyethylene, polypropylene, polyvinylidene fluoride, polytetrafluoroethylene, polyacrylonitrile, polysulfone or polyethersulfone, and even more preferably polyacrylonitrile, polysulfone or polyvinylidene fluoride.

[0369] Specifically, examples of ultrafiltration membranes mentioned above include: DESAL's G-5, G-10, G-20, G-50, PW, and HWS UF types; KOCH's HFM-180, HFM-183, HFM-251, HFM-300, HFM-116, HFM-183, HFM-300, HFK-131, HFK-328, MPT-U20, MPS-U20P, and MPS-U20S; Synder's SPE1, SPE3, SPE5, SPE10, SPE30, SPV5, SPV50, and SOW30; Asahi Kasei's Microza (registered trademark) UF series; and Nitto Denko's NTR7410, etc.

[0370] From the perspective of the removal efficiency of dimers and trimers, the above-mentioned ultrafiltration is preferably carried out at a pressure of 0.01 MPa or higher. More preferably, it is 0.03 MPa or higher, and even more preferably, it is 0.05 MPa or higher. In addition, from the perspective of pressure resistance, the above-mentioned pressure is preferably 0.5 MPa or lower, more preferably 0.25 MPa or lower, and even more preferably 0.2 MPa or lower.

[0371] From the perspective of the removal efficiency of dimers and trimers, the above-mentioned ultrafiltration is preferably carried out at a flow rate of 10 mL / min or more, more preferably at a flow rate of 50 mL / min or more, and preferably at a flow rate of 5000 mL / min or less, more preferably at a flow rate of 1000 mL / min or less.

[0372] The microporous filtration described above can be achieved using microporous filter membranes. Microporous filter membranes typically have an average pore size of 0.05–1.0 μm.

[0373] For the purpose of effectively removing dimers and trimers, the average pore size of the microporous filter membrane is preferably 0.1 μm or more. More preferably, it is 0.075 μm or more, and even more preferably, it is 0.1 μm or more. Furthermore, the average pore size is preferably 1.00 μm or less. More preferably, it is 0.50 μm or less, and even more preferably, it is 0.25 μm or less.

[0374] The average pore size of the microporous filter membrane described above can be determined according to ASTM F316-03 (bubble point method).

[0375] As for the shape of the aforementioned microporous filter membrane, there are currently known shapes that are not limited, such as hollow fiber type, flat membrane type, spiral type, tubular type, etc. From the perspective of suppressing clogging, hollow fiber type is preferred.

[0376] The inner diameter of the hollow fiber microporous filter membrane is not limited, and can be, for example, 0.1 to 2 mm. Preferably, it is 0.8 to 1.4 mm.

[0377] The length of the hollow fiber microporous filter membrane is not limited, and can be, for example, 0.05 to 3 m. Preferably, it is 0.05 to 2 m.

[0378] Examples of materials that can be used for the aforementioned microporous filter membrane include cellulose-based materials, aromatic polyamides, polyvinyl alcohol, polysulfone, polyethersulfone, polyvinylidene fluoride, polyethylene, polyacrylonitrile, polypropylene, polycarbonate, polytetrafluoroethylene, ceramics, and metals. Among these, aromatic polyamides, polyvinyl alcohol, polysulfone, polyvinylidene fluoride, polyethylene, polyacrylonitrile, polypropylene, polycarbonate, or polytetrafluoroethylene are preferred, with polyacrylonitrile or polyvinylidene fluoride being particularly preferred.

[0379] Specifically, examples of microporous filtration membranes include Cefilt manufactured by Nippon Keigo Co., Ltd.; Microza U series and Microza P series manufactured by Asahi Kasei Corporation; Poreflon SPMW, Poreflon OPMW, and Poreflon PM manufactured by Sumitomo Electric Industries, Ltd.; Trefil manufactured by Toray Industries, Ltd.; NADIR MP005 and NADIRMV020 manufactured by Microdyn-Nadir Corporation; and X-flow manufactured by Norit Corporation.

[0380] From the perspective of removing dimers and trimers, the microporous filtration described above is preferably carried out at a pressure of 0.01 MPa or higher. More preferably, it is 0.03 MPa or higher, and even more preferably, it is 0.05 MPa or higher. In addition, from the perspective of pressure resistance, the pressure is preferably 0.5 MPa or lower, more preferably 0.25 MPa or lower, and even more preferably 0.2 MPa or lower.

[0381] From the perspective of the removal efficiency of dimers and trimers, the above-mentioned microporous filtration is preferably carried out at a flow rate of 10 mL / min or more, more preferably at a flow rate of 50 mL / min or more, and preferably at a flow rate of 5000 mL / min or less, more preferably at a flow rate of 1000 mL / min or less.

[0382] The above dialysis membrane treatment is performed using a dialysis membrane. Dialysis membranes typically have a density of 0.05 × 10⁻⁶. 4 ~100×10 4 The molecular weight cutoff of Da.

[0383] To prevent membrane clogging and effectively remove dimers and trimers, the preferred molecular weight cutoff of the dialysis membrane is 0.3 × 10⁻⁶. 4 The molecular weight cutoff is more preferably 0.5 × 10⁻⁶.4 Da or higher, and more preferably 0.6×10 4 Da or higher, and more preferably 0.8 × 10 4 The molecular weight cutoff is above 1.0 × 10⁻⁶. 4 Big or above.

[0384] Furthermore, considering the removal efficiency of dimers and trimers, the preferred molecular weight cutoff is 20 × 10⁻⁶. 4 Da or less, more preferably 10×10 4 The following is a summary of the above.

[0385] The molecular weight cutoff of the dialysis membrane can be determined, for example, by the same method used for ultrafiltration membranes.

[0386] There are no particular limitations on the materials used for the aforementioned dialysis membranes; examples include cellulose, polyacrylonitrile, polymethyl methacrylate, ethylene vinyl alcohol copolymer, polysulfone, polyamide, and polyester polymer alloys.

[0387] Specifically, examples of dialysis membranes include Spectra / Por (registered trademark) Float-A-Lyzer, Tube-A-Lyzer, Dialysis tubing, 6Dialysis tubing, and 7Dialysis tubing manufactured by Spectrum Laboratories.

[0388] The above-mentioned ultrafiltration, microfiltration, or dialysis membrane treatment is preferably performed at a temperature of 10°C or higher. More preferably, it is 15°C or higher, even more preferably 20°C or higher, and particularly preferably 30°C or higher. By maintaining the temperature within the above range, dimers and trimers can be effectively reduced. The above-mentioned temperature is preferably 90°C or lower, more preferably 80°C or lower, even more preferably 70°C or lower, and particularly preferably 60°C or lower.

[0389] For ultrafiltration, microfiltration, or dialysis membrane treatment, water can be added to the composition while the pH of the composition is being adjusted. Water can be added to the composition intermittently or continuously.

[0390] The endpoint of ultrafiltration, microfiltration, or dialysis membrane treatment can be appropriately determined without limitation. Furthermore, in the aforementioned ultrafiltration, microfiltration, or dialysis membrane treatments, to improve the durability of the filter membrane, backwashing with water approximately once is performed, based on a filtration time of 1 to 24 hours.

[0391] Liquid separation can be carried out, for example, by adding an organic solvent to the composition to separate it into two phases: an aqueous phase and an organic solvent phase, and recovering the aqueous phase.

[0392] Reprecipitation can be carried out, for example, by adding the composition dropwise to a poor solvent to precipitate the fluoropolymer, recovering the precipitated fluoropolymer, dissolving the recovered fluoropolymer in a good solvent, adding the resulting solution dropwise to the poor solvent to precipitate the fluoropolymer again, and recovering the precipitated fluoropolymer, thereby carrying out reprecipitation.

[0393] Compositions containing monomer (I) of fluoropolymers are post-treated using the methods described above, typically yielding an aqueous solution containing either a fluoropolymer substantially free of dimers and trimers, or an aqueous solution containing a fraction with a reduced molecular weight of 3000 or less. The aqueous solution containing the fluoropolymer obtained by treating the composition can be used directly for various applications, or the fluoropolymer obtained by separation from the aqueous solution can be used for various applications. There are no particular limitations on the method for separating the fluoropolymer from the aqueous solution. For example, the fluoropolymer can be separated by precipitation, washing, drying, or other methods from the aqueous solution.

[0394] The manufacturing method described above yields a fluoropolymer or an aqueous solution containing a fluoropolymer and an aqueous medium.

[0395] The embodiments have been described above, but it is understood that various changes in form and detail may be made without departing from the spirit and scope of the claims.

[0396] Example

[0397] The following examples illustrate the implementation of this disclosure, but this disclosure is not limited to these examples.

[0398] The values ​​in the examples were measured using the following methods.

[0399] (Oxygen concentration inside the reactor)

[0400] The gas discharged from the reactor under N2 flow was measured and analyzed using a low-concentration oxygen analyzer (trade name "PS-820-L", manufactured by Iijima Electronics Co., Ltd.) to determine the oxygen concentration during the reaction.

[0401] (Concentration of fluoropolymers in aqueous solution (concentration of solid components))

[0402] Approximately 1 g of an aqueous solution containing a fluoropolymer was dried in a vacuum dryer at 60°C for 60 minutes. The mass of the heating residue was determined, and the value was expressed as a percentage of the mass of the heating residue relative to the mass of the aqueous solution (1 g).

[0403] (Methods for determining the content of weight-average molecular weight (Mw), number-average molecular weight (Mn), and fractions with a molecular weight of less than 3000)

[0404] Regarding the Mw and Mn of fluoropolymers, gel permeation chromatography (GPC) was performed using an Agilent Technologies 1260 Infinity II column (connected to a TSK gel G3000 PW column) with the Mw and Mn of the fluoropolymers. XL and 1 TSGgel GMPW XL The solution is connected and used to perform the determination by passing a mixture of tris(hydroxymethyl)aminomethane buffer and acetonitrile (tris(hydroxymethyl)aminomethane buffer:acetonitrile = 8:2 (v / v)) at a flow rate of 0.5 ml / min. The molecular weight is calculated by using monodisperse polyethylene oxide (PEO) and polyethylene glycol (PEG) as standards.

[0405] (Alternation rate)

[0406] Performing fluoropolymers 19 F-NMR measurements, based on the "OCF2" appearing in the NMR spectrum from CF2=CFOCF2CF2SO3Na * The total integral values ​​of the two peaks (the peak appearing in -75ppm to -80ppm and the peak appearing in -80ppm to -84ppm) are calculated according to the following formula.

[0407] Alternation rate (%) ≥ (b×2) / (a+b)×100

[0408] a: Total integral value of peaks in the -75ppm to -80ppm region

[0409] b: Total integral value of peaks in the -80ppm to -84ppm region

[0410] The calculated alternation rate is the proportion of polymer units in the fluoropolymer based on CF2=CFOCF2CF2SO3Na that are adjacent to the VdF-based polymer units.

[0411] Based on VdF(C * The carbon atoms (C) in the polymer unit of H2=CF2) * (relative to CF2=C) * The carbon atom (C) in the polymerization unit of FOCF2CF2SO3Na * The combination ratio of ) is calculated using the following formula.

[0412] Proportion (%) = (b × 2) / (a ​​+ b) × 100

[0413] Based on VdF(C * The carbon atoms (C) in the polymer unit of H2=CF2) * Other carbon atoms (based on CF2=C) * The carbon atom (C) in the polymerization unit of FOCF2CF2SO3Na ** ) and based on VdF(CH2=C ** The carbon atoms (C) in the polymer unit of F2) ** Compared to C-based ** F2 = C ** The carbon atom (C) in the polymerization unit of FOCF2CF2SO3Na * The combination ratio of ) is calculated using the following formula.

[0414] Proportion (%) = (ab) / (a+b) × 100

[0415] (Methods for determining the content of dimers and trimers of monomers in fluoropolymers)

[0416] (1) Extraction from aqueous solution

[0417] To determine the solid content of the aqueous solution containing the fluoropolymer, a volume equivalent to 0.2 g of the solid content of the fluoropolymer was weighed. This volume was then combined with the water contained in the aqueous solution, and water and methanol were added at a volume ratio of 50 / 50 (volume %) to obtain a mixture containing the fluoropolymer, water, and methanol. The resulting mixture was then filtered using an ultrafiltration plate (molecular weight cutoff 3000 Da), and the recoverable liquid containing the fluoropolymer was collected.

[0418] The recovered liquid was analyzed using a liquid chromatography-mass spectrometry (Waters, LC-MS ACQUITY UPLC / TQD) instrument, and the chromatogram of the recovered liquid was obtained.

[0419] Regarding the content of dimers and trimers of the monomer contained in the recovered liquid, the integral values ​​of the peaks of dimers and trimers of the monomer appearing in the chromatogram of the recovered liquid, which are analogous to the monomers, are converted into the content of dimers and trimers of the monomers using the calibration curve of the monomers.

[0420] (2) Correction curve of monomer

[0421] Five methanol standard solutions of monomers with known concentrations ranging from 1 ng / mL to 100 ng / mL were prepared at five levels and analyzed using a liquid chromatography-mass spectrometry (Waters, LC-MS ACQUITY UPLC / TQD). Calibration curves (first approximation) were constructed for each monomer by plotting the relationship between the concentration of each monomer and the peak integral relative to that concentration. Then, calibration curves for the dimers and trimers of each monomer were constructed using these first approximation calibration curves.

[0422] Equipment composition and LC-MS measurement conditions

[0423] [Table 1]

[0424]

[0425] The limit of quantitation in this assay device is 1 ng / mL.

[0426] <Synthesis example 1>

[0427] 170 g of sodium 1,1,2,2-tetrafluoro-2-((1,2,2-trifluorovinyl)oxy)ethane-1-sulfonate, 340 g of water, and 2.0 mol% ammonium persulfate (APS) relative to the amount of sodium 1,1,2,2-tetrafluoro-2-((1,2,2-trifluorovinyl)oxy)ethane-1-sulfonate were added to the reactor, and the mixture was stirred at 40 °C for 72 hours under N2 flow. The oxygen concentration in the reactor ranged from 15 ppm to 800 ppm.

[0428] Water was added to the obtained aqueous solution containing the fluoropolymer to adjust the concentration of the fluoropolymer to 3.8% by mass. Ultrafiltration was then performed at 25°C and a water pressure of 0.1 MPa, bringing the fluoropolymer into contact with an ultrafiltration membrane (6000 Da molecular weight cutoff, polysulfone). Ultrafiltration continued while appropriately adding water until a filtrate of four times the volume of water relative to the aqueous solution was finally eluted, yielding an aqueous solution containing a fluoropolymer based on repeating units of sodium 1,1,2,2-tetrafluoro-2-((1,2,2-trifluorovinyl)oxy)ethane-1-sulfonate. The concentration of the aqueous solution obtained by ultrafiltration was 1.6% by mass.

[0429] The aqueous solution obtained by ultrafiltration was analyzed. The weight-average molecular weight (Mw) of the obtained fluoropolymer was 1.0 × 10⁻⁶. 4 The number-average molecular weight (Mn) is 0.8 × 10⁻⁶. 4The content of dimers and trimers based on repeating units of sodium 1,1,2,2-tetrafluoro-2-((1,2,2-trifluorovinyl)oxy)ethane-1-sulfonate in the aqueous solution obtained by ultrafiltration is less than 0.1% by mass relative to the fluoropolymer. The content of fractions with a molecular weight of less than 3000 in the aqueous solution obtained by ultrafiltration is less than 0.5%. DLS analysis of this aqueous solution did not allow for particle size determination.

[0430] <Synthesis example 2>

[0431] 300 ml of AMBERLITE (IR120B(H)-HG) was measured into a container, washed with water until no color was observed, and then 500 ml of 1M-HCl was added. The mixture was stirred at room temperature for 1 hour. AMBERLITE was packed into a stopcock column, and water was allowed to flow through until the acidity of the waste liquid became neutral. The aqueous solution containing the fluoropolymer obtained in Synthesis Example 1 was added dropwise to the stopcock column. After the addition was completed, water was allowed to flow through until the added solution became neutral, resulting in an aqueous solution containing a fluoropolymer based on repeating units of 1,1,2,2-tetrafluoro-2-((1,2,2-trifluorovinyl)oxy)ethane-1-sulfonic acid. The concentration of the resulting aqueous solution was 1.5% by mass.

[0432] The aqueous solution obtained by treatment with a cation exchange resin was analyzed. The weight-average molecular weight (Mw) of the obtained fluoropolymer was 1.0 × 10⁻⁶. 4 The number-average molecular weight (Mn) is 0.8 × 10⁻⁶. 4 The content of dimers and trimers based on repeating units of 1,1,2,2-tetrafluoro-2-((1,2,2-trifluorovinyl)oxy)ethane-1-sulfonic acid in the aqueous solution obtained by treatment with cation exchange resin is less than 0.1% by mass relative to the fluoropolymer. The content of fractions with a molecular weight of less than 3000 in the aqueous solution obtained by treatment with cation exchange resin is less than 0.5%. DLS analysis of this aqueous solution did not allow for particle size determination.

[0433] <Synthesis Example 3>

[0434] 10 g of sodium 1,1,2,2-tetrafluoro-2-((1,2,2-trifluorovinyl)oxy)ethane-1-sulfonate, 20 g of water, and 2.0 mol% ammonium persulfate (APS) relative to the amount of sodium 1,1,2,2-tetrafluoro-2-((1,2,2-trifluorovinyl)oxy)ethane-1-sulfonate were added to the reactor, and the mixture was stirred at 52 °C for 72 hours under N2 flow. The oxygen concentration in the reactor ranged from 20 ppm to 70 ppm.

[0435] Water was added to the obtained aqueous solution containing the fluoropolymer to adjust the concentration of the fluoropolymer to 3.8% by mass. Ultrafiltration was then performed at 25°C and a water pressure of 0.1 MPa, bringing the fluoropolymer into contact with an ultrafiltration membrane (6000 Da molecular weight cutoff, polysulfone). Ultrafiltration continued while appropriately adding water until a filtrate of four times the volume of water relative to the aqueous solution was finally eluted, yielding an aqueous solution containing a fluoropolymer based on repeating units of sodium 1,1,2,2-tetrafluoro-2-((1,2,2-trifluorovinyl)oxy)ethane-1-sulfonate. The concentration of the aqueous solution obtained by ultrafiltration was 1.8% by mass.

[0436] The aqueous solution obtained by ultrafiltration was analyzed. The weight-average molecular weight (Mw) of the obtained fluoropolymer was 0.7 × 10⁻⁶. 4 The number-average molecular weight (Mn) is 0.6 × 10⁻⁶. 4 The content of dimers and trimers based on repeating units of sodium 1,1,2,2-tetrafluoro-2-((1,2,2-trifluorovinyl)oxy)ethane-1-sulfonate in the aqueous solution obtained by ultrafiltration is less than 0.1% by mass relative to the fluoropolymer. The content of fractions with a molecular weight of less than 3000 in the aqueous solution obtained by ultrafiltration is less than 0.5%. DLS analysis of this aqueous solution did not allow for particle size determination.

[0437] <Synthesis example 4>

[0438] Measure 20 ml of AMBERLITE (IR120B(H)-HG) into a container, wash with water until no color is found, add 40 ml of 1M-HCl, and stir at room temperature for 1 hour. Pack AMBERLITE into a stopcock column and allow water to flow until the acidity of the waste liquid becomes neutral. Add the aqueous solution containing the fluoropolymer obtained in Synthesis Example 3 into the stopcock column to begin dropwise addition. After the addition is complete, allow water to flow until the added solution becomes neutral, yielding an aqueous solution containing a fluoropolymer based on repeating units of 1,1,2,2-tetrafluoro-2-((1,2,2-trifluorovinyl)oxy)ethane-1-sulfonic acid. The concentration of the obtained aqueous solution is 2.0% by mass.

[0439] The aqueous solution obtained by treatment with a cation exchange resin was analyzed. The weight-average molecular weight (Mw) of the obtained fluoropolymer was 0.7 × 10⁻⁶. 4 The number-average molecular weight (Mn) is 0.6 × 10⁻⁶. 4The content of dimers and trimers based on repeating units of 1,1,2,2-tetrafluoro-2-((1,2,2-trifluorovinyl)oxy)ethane-1-sulfonic acid in the aqueous solution obtained by treatment with cation exchange resin is less than 0.1% by mass relative to the fluoropolymer. The content of fractions with a molecular weight of less than 3000 in the aqueous solution obtained by treatment with cation exchange resin is less than 0.5%. DLS analysis of this aqueous solution did not allow for particle size determination.

[0440] <Synthesis example 5>

[0441] 10 g of sodium 1,1,2,2-tetrafluoro-2-((1,2,2-trifluorovinyl)oxy)ethane-1-sulfonate, 20 g of water, and an amount equivalent to 2.0 mol% of ammonium persulfate (APS) were added to the reactor. The reactor was stirred at 40 °C for 72 hours under N2 flow. The oxygen concentration in the reactor ranged from 15 ppm to 40 ppm.

[0442] The resulting aqueous solution containing the fluoropolymer was filtered through a dialysis membrane (3500 Da molecular weight cutoff, made of cellulose) at room temperature to obtain an aqueous solution containing the fluoropolymer. The concentration of the aqueous solution obtained by dialysis membrane purification was 1.8% by mass.

[0443] The aqueous solution obtained by dialysis membrane purification was analyzed. The weight-average molecular weight (Mw) of the obtained fluoropolymer was 1.0 × 10⁻⁶. 4 The number-average molecular weight (Mn) is 0.7 × 10⁻⁶. 4 The content of dimers and trimers based on repeating units of sodium 1,1,2,2-tetrafluoro-2-((1,2,2-trifluorovinyl)oxy)ethane-1-sulfonate in the aqueous solution obtained by dialysis membrane purification is less than 0.1% by mass relative to the fluoropolymer. The content of fractions with a molecular weight of less than 3000 in the aqueous solution obtained by dialysis membrane purification is less than 0.5%. DLS analysis of this aqueous solution did not allow for particle size determination.

[0444] <Synthesis Example 6>

[0445] 6.8 g of sodium 1,1,2,2-tetrafluoro-2-((1,2,2-trifluorovinyl)oxy)ethane-1-sulfonate, 34 g of water, and 1.5 mol% ammonium persulfate (APS) relative to the amount of sodium 1,1,2,2-tetrafluoro-2-((1,2,2-trifluorovinyl)oxy)ethane-1-sulfonate were added to the reactor. After N2 replacement and degassing, 3.2 g of VdF was introduced, and the reactor was stirred at 60 °C for 2 hours under sealed conditions. The internal pressure of the reactor was increased to 0.30 MPaG after heating and decreased to 0.19 MPaG as the reaction proceeded.

[0446] The resulting aqueous solution containing the fluoropolymer was filtered through a dialysis membrane (3500 Da molecular weight cutoff, made of cellulose) at room temperature to obtain an aqueous solution containing the fluoropolymer. The concentration of the aqueous solution obtained by dialysis membrane purification was 2.65% by mass.

[0447] The polymer composition was investigated by analyzing the aqueous solution obtained through dialysis using NMR. The results showed that the molar ratio of CF2=CFOCF2CF2SO3Na-based polymeric units to VdF-based polymeric units in the polymer was 1.0 / 1.0 (mass ratio 82 / 18). Furthermore, the alternation rate of CF2=CFOCF2CF2SO3Na-based polymeric units to VdF-based polymeric units in the fluoropolymer was over 76%.

[0448] The weight-average molecular weight (Mw) of the obtained fluoropolymer was 15.3 × 10⁻⁶. 4 The number-average molecular weight (Mn) is 7.2 × 10⁻⁶. 4 The content of dimers and trimers based on CF2=CFOCF2CF2SO3Na polymer units in the aqueous solution obtained by dialysis is 0.1% by mass or less relative to the fluoropolymer. Furthermore, the content of dimers and trimers composed of polymer units based on CF2=CFOCF2CF2SO3Na and VdF-based polymer units is 0.1% by mass or less relative to the fluoropolymer. The content of fractions with a molecular weight of 3000 or less in the aqueous solution obtained by dialysis is 0.1% by mass or less.

[0449] <Synthesis Example 7>

[0450] 2.42 g of CF2=CFOCF2CF2COOH, 3.16 g of CF2=CFOCF2CF2SO3Na, 11 g of water, and an amount of ammonium persulfate (APS) equivalent to 1.5 mol% of the total amount of CF2=CFOCF2CF2COOH and CF2=CFOCF2CF2SO3Na were added to the reactor. The mixture was stirred at 40°C for 21 hours under N2 flow, and then further stirred at room temperature for 91 hours. The oxygen concentration in the reactor ranged from 66 ppm to 98 ppm.

[0451] The obtained aqueous solution containing the fluoropolymer was added to a dialysis membrane (3500 Da molecular weight cutoff, made of cellulose) and dialyzed in contact with water at room temperature to obtain an aqueous solution containing the fluoropolymer. The concentration of the aqueous solution obtained by dialysis membrane purification was 1.1% by mass.

[0452] The polymer composition was investigated by analyzing the aqueous solution obtained by dialysis using NMR. The results showed that the molar ratio of polymeric units based on CF2=CFOCF2CF2COOH to polymeric units based on CF2=CFOCF2CF2SO3Na was 1.0 / 0.8 (mass ratio 50 / 50).

[0453] The weight-average molecular weight (Mw) of the obtained fluoropolymer was 2.0 × 10⁻⁶. 4 The number-average molecular weight (Mn) is 1.3 × 10⁻⁶. 4 The content of dimers and trimers based on the polymeric unit CF2=CFOCF2CF2SO3Na in the aqueous solution obtained by dialysis is 0.1% by mass or less relative to the fluoropolymer. Furthermore, the content of dimers and trimers composed of polymeric units based on CF2=CFOCF2CF2COOH and polymeric units based on CF2=CFOCF2CF2SO3Na is 0.1% by mass or less relative to the fluoropolymer. The content of fractions with a molecular weight of 3000 or less in the aqueous solution obtained by dialysis is 0.1% by mass or less.

[0454] <Synthesis example 8>

[0455] 1 g of CF2=CFOCF2CF2SO3Na, 2 g of pure water, and APS in an amount equivalent to 24 mol% relative to CF2=CFOCF2CF2SO3Na were added to the reactor, and the mixture was stirred at 40°C for 72 hours under N2 flow. The oxygen concentration in the reactor ranged from 40 ppm to 95 ppm by volume.

[0456] The obtained aqueous solution containing the fluoropolymer was added to a dialysis membrane (3500 Da molecular weight cutoff, made of cellulose) and dialyzed in contact with water at room temperature to obtain an aqueous solution containing the fluoropolymer. The concentration of the aqueous solution obtained by dialysis membrane purification was 2.1% by mass.

[0457] The weight-average molecular weight (Mw) of the obtained fluoropolymer was 0.8 × 10⁻⁶. 4 The number-average molecular weight (Mn) is 0.6 × 10⁻⁶. 4 The content of dimers and trimers based on the polymeric units CF2=CFOCF2CF2SO3Na in the aqueous solution obtained by dialysis is less than 0.1% by mass relative to the fluoropolymer. The content of fractions with a molecular weight of less than 3000 in the aqueous solution obtained by dialysis is less than 0.1% by mass.

[0458] <Synthesis Example 9>

[0459] 1 g of CF2=CFOCF2CF2SO3Na, 2 g of pure water, and APS in an amount equivalent to 2 mol% of CCF2=CFOCF2CF2SO3Na were added to the reactor, and the mixture was stirred at 52°C for 72 hours under N2 flow. The oxygen concentration in the reactor ranged from 35 ppm to 95 ppm.

[0460] The obtained aqueous solution containing the fluoropolymer was added to a dialysis membrane (3500 Da molecular weight cutoff, made of cellulose) and dialyzed in contact with water at room temperature to obtain an aqueous solution containing the fluoropolymer. The concentration of the aqueous solution obtained by dialysis membrane purification was 2.1% by mass.

[0461] The weight-average molecular weight (Mw) of the obtained fluoropolymer was 0.7 × 10⁻⁶. 4 The number-average molecular weight (Mn) is 0.6 × 10⁻⁶. 4 The content of dimers and trimers based on the polymeric units CF2=CFOCF2CF2SO3Na in the aqueous solution obtained by dialysis is less than 0.1% by mass relative to the fluoropolymer. The content of fractions with a molecular weight of less than 3000 in the aqueous solution obtained by dialysis is less than 0.1% by mass.

[0462] <Synthesis Example 10>

[0463] 6.3 g of sodium 1,1,2,2-tetrafluoro-2-((1,2,2-trifluorovinyl)oxy)ethane-1-sulfonate, 34 g of water, and 5.0 mol% ammonium persulfate (APS) relative to the amount of sodium 1,1,2,2-tetrafluoro-2-((1,2,2-trifluorovinyl)oxy)ethane-1-sulfonate were added to the reactor. After N2 replacement and degassing, 3.3 g of VdF was introduced, and the reactor was stirred at 78 °C for 4 hours under sealed conditions. The internal pressure of the reactor was increased to 0.38 MPaG after heating and decreased to 0.34 MPaG as the reaction proceeded.

[0464] The resulting aqueous solution containing the fluoropolymer was filtered through a dialysis membrane (3500 Da molecular weight cutoff, made of cellulose) at room temperature to obtain an aqueous solution containing the fluoropolymer. The concentration of the aqueous solution obtained by dialysis membrane purification was 1.3% by mass.

[0465] The polymer composition was investigated by NMR analysis of the aqueous solution obtained through dialysis. The results showed that the molar ratio of sodium 1,1,2,2-tetrafluoro-2-((1,2,2-trifluorovinyl)oxy)ethane-1-sulfonate-based polymeric units to VdF-based polymeric units was 1.0 / 0.5 (90 / 10 by mass). Furthermore, the alternation rate between sodium 1,1,2,2-tetrafluoro-2-((1,2,2-trifluorovinyl)oxy)ethane-1-sulfonate-based polymeric units and VdF-based polymeric units in the fluoropolymer was over 41%.

[0466] The weight-average molecular weight (Mw) of the obtained fluoropolymer was 1.0 × 10⁻⁶. 4 The number-average molecular weight (Mn) is 0.8 × 10⁻⁶. 4 The content of dimers and trimers based on the polymeric units of sodium 1,1,2,2-tetrafluoro-2-((1,2,2-trifluorovinyl)oxy)ethane-1-sulfonate in the aqueous solution obtained by dialysis is 0.1% by mass or less relative to the fluoropolymer. Furthermore, the content of dimers and trimers composed of polymeric units based on sodium 1,1,2,2-tetrafluoro-2-((1,2,2-trifluorovinyl)oxy)ethane-1-sulfonate and VdF-based polymeric units is 0.1% by mass or less relative to the fluoropolymer. The content of fractions with a molecular weight of 3000 or less in the aqueous solution obtained by dialysis is 0.1% by mass or less.

[0467] <Synthesis Example 11>

[0468] 6.3 g of sodium 1,1,2,2-tetrafluoro-2-((1,2,2-trifluorovinyl)oxy)ethane-1-sulfonate, 34 g of water, and ammonium persulfate (APS) in an amount equivalent to 10 mol% of sodium 1,1,2,2-tetrafluoro-2-((1,2,2-trifluorovinyl)oxy)ethane-1-sulfonate were added to the reactor. After N2 replacement and degassing, 5.0 g of VdF was introduced, and the reactor was stirred at 58 °C for 1 hour under sealed conditions. The internal pressure of the reactor was increased to 0.55 MPaG after heating and decreased to 0.40 MPaG as the reaction proceeded.

[0469] The obtained aqueous solution containing the fluoropolymer was filtered through a dialysis membrane (3500 Da molecular weight cutoff, made of cellulose) at room temperature to obtain an aqueous solution containing the fluoropolymer. The concentration of the aqueous solution obtained by dialysis membrane purification was 2.9% by mass.

[0470] The polymer composition was investigated by NMR analysis of the aqueous solution obtained through dialysis. The results showed that the molar ratio of sodium 1,1,2,2-tetrafluoro-2-((1,2,2-trifluorovinyl)oxy)ethane-1-sulfonate-based polymeric units to VdF-based polymeric units was 1.0 / 1.1 (mass ratio 81 / 19). Furthermore, the alternation rate between sodium 1,1,2,2-tetrafluoro-2-((1,2,2-trifluorovinyl)oxy)ethane-1-sulfonate-based polymeric units and VdF-based polymeric units in the fluoropolymer was over 65%.

[0471] The weight-average molecular weight (Mw) of the obtained fluoropolymer was 13.6 × 10⁻⁶. 4 The number-average molecular weight (Mn) is 7.6 × 10⁻⁶. 4 The content of dimers and trimers based on the polymeric units of sodium 1,1,2,2-tetrafluoro-2-((1,2,2-trifluorovinyl)oxy)ethane-1-sulfonate in the aqueous solution obtained by dialysis is 0.1% by mass or less relative to the fluoropolymer. Furthermore, the content of dimers and trimers composed of polymeric units based on sodium 1,1,2,2-tetrafluoro-2-((1,2,2-trifluorovinyl)oxy)ethane-1-sulfonate and VdF-based polymeric units is 0.1% by mass or less relative to the fluoropolymer. The content of fractions with a molecular weight of 3000 or less in the aqueous solution obtained by dialysis is 0.1% by mass or less.

[0472] <Experimental Example 1 (Preparation of Coated Film)>

[0473] To achieve the goal of forming a 1 μm thick film on the substrate, the weight-average molecular weight (Mw) of the aqueous solution obtained by ultrafiltration in Synthesis Example 1 was adjusted to 1.0 × 10⁻⁶. 4To prepare a fluoropolymer solution with a concentration of 10% by mass, the solution was stirred for 24 hours and then filtered through a disposable syringe filter with a pore size of 0.2 μm to obtain a spin-coating solution.

[0474] Using the obtained spin coating solution and a commercially available programmed spin coater, spin coating was performed on a silicon wafer substrate under the following conditions: The spin coating solution was applied to the substrate while rotating it at 200 rpm for 10 seconds, followed by another application of the spin coating solution while rotating it at 500 rpm for 50 seconds. After film formation, the substrate was immediately dried in a blower-type furnace at 50°C for 8 hours, and then the substrate with the coated film was removed. The film thickness at five points was measured using a digital thickness gauge. The average film thickness was 0.95 μm, indicating that a uniformly formed coating film with the target thickness was achieved.

[0475] <Comparative Example 1 (Preparation of Coated Film)>

[0476] Besides using homopolymers with CH2=CF(CF2OCFCF3COOH) (weight average molecular weight (Mw) ≥ 40×10 4 Instead of the aqueous solution obtained by ultrafiltration in Synthesis Example 1, the same operation as in Experimental Example 1 was performed, but a uniform coated film was not obtained, and the film thickness was significantly uneven.

[0477] <Comparative Example 2 (Preparation of Coated Film)>

[0478] Except that a copolymer of sodium 1,1,2,2-tetrafluoro-2-((1,2,2-trifluorovinyl)oxy)ethane-1-sulfonate and tetrafluoroethylene (monomer mass ratio of 37 / 63 (mass%)) was used instead of the aqueous solution obtained by ultrafiltration in Synthesis Example 1, the same procedure as in Experimental Example 1 was performed. A 10% (mass) aqueous solution could not be prepared, precipitation was observed, and a coated film could not be formed.

Claims

1. A fluoropolymer, which is a fluoropolymer of monomer (I) represented by general formula (I), wherein, The content of monomer-based polymeric unit (I) is 80% by mass or more, relative to all polymeric units constituting the fluoropolymer. General formula (I): CX2=CX-O-Rf-SO3M In the formula, X is independently F or CF3, Rf is a fluorinated alkylene group with 1 to 40 carbon atoms, or a fluorinated alkylene group with 2 to 100 carbon atoms and an ether bond or ketone group; M is -H, a metal atom, or -NR. 7 4. Imidazolium with or without substituents, pyridinium with or without substituents, or phosphonium with or without substituents, R 7 It is an H or an organic group.

2. The fluoropolymer as described in claim 1, wherein, The weight-average molecular weight, Mw, is 0.6 × 10⁻⁶. 4 above.

3. The fluoropolymer as described in claim 1 or 2, wherein, Molecular weight distribution, i.e., Mw / Mn is below 3.

0.

4. The fluoropolymer as described in claim 1 or 2, wherein, X is always F.

5. The fluoropolymer as described in claim 1 or 2, wherein, Rf is a fluorinated alkylene group having 1 to 5 carbon atoms, or a fluorinated alkylene group having 2 to 5 carbon atoms and having an ether bond or a ketone group.

6. The fluoropolymer as described in claim 1 or 2, wherein, The fluoropolymer is a copolymer of monomer (I) and monomer represented by the general formula CFR=CR2, in which R is independently H, F or a perfluoroalkyl group having 1 to 4 carbon atoms.

7. The fluoropolymer as described in claim 1 or 2, wherein, The content of polymer unit (I) is 99% by mass or more relative to all polymer units constituting the fluoropolymer.

8. The fluoropolymer as described in claim 1 or 2, wherein, The fluoropolymer consists of only polymer units (I).

9. The fluoropolymer as described in claim 1 or 2, wherein, The fluoropolymer does not substantially contain dimers or trimers of monomer (I).

10. The fluoropolymer as described in claim 1 or 2, wherein, Compared to fluoropolymers, the content of fractions with a molecular weight of less than 3000 is less than 0.5%.

11. An aqueous solution comprising the fluoropolymer according to any one of claims 1 to 10.

12. The aqueous solution of claim 11, wherein, The content of the fluoropolymer relative to the aqueous solution is 2% by mass or more.

13. A coating composition comprising a fluoropolymer as described in any one of claims 1 to 10, or comprising an aqueous solution as described in claim 11 or 12.

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