Composition comprising water and fluoropolymer

Abstract

The present invention relates to a composition comprising water and a fluorine-containing polymer, the fluorine-containing polymer being a polymer comprising a structural unit M3 from a monomer represented by general formula (1). CX2 = CY (-CZ2-O-Rf-A) (1) (In the formula, X is the same or different and is-H or-F, Y is-H,-F, an alkyl group or a fluorine-containing alkyl group, and Z is the same or different and is-H,-F, an alkyl group or a fluoroalkyl group. And Rf represents a fluorine-containing alkylene group having 1 to 40 carbon atoms, or a fluorine-containing alkylene group having 2 to 100 carbon atoms and having an ether bond. A is-COOM,-SO3M,-OSO3M, or-C (CF3) 2OM (M is-H, a metal atom,-NR74, an imidazolium having or not having a substituent, a pyridinium having or not having a substituent, or a phosphonium having or not having a substituent, and R7 is H or an organic group). Wherein at least one of X, Y, and Z contains a fluorine atom).

Description

[0001] This application is a divisional application. The application number of the original application is 202080031483.5, the application date is April 27, 2020, and the name of the invention is “Method for manufacturing a composition and a composition”. Technical Field

[0002] The present invention relates to a method for producing a composition and the composition. Background Art

[0003] In recent years, fluorinated polymers having a sulfonic acid group or a carboxyl group have attracted attention as materials for electrolyte membranes of fuel cells, chemical sensors, and the like, and research has been conducted thereon.

[0004] For example, Patent Document 1 describes a method for producing a fluorinated polymer dispersion, which is a method for producing a fluorinated polymer dispersion having an acid treatment step, wherein the acid treatment step comprises adding an acid to an aqueous dispersion containing a fluorinated polymer precursor and performing ultrafiltration. The method for producing a fluorinated polymer dispersion is characterized in that:

[0005] The above fluorinated polymer precursor has -SO3X 1 and / or -COOZ 1 (X 1 Indicates M 1 1 / L or NR 1 R 2 R 3 R 4 , R 1 , R 2 , R 3 and R 4 are the same or different and represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. 1 Indicates M 2 1 / L or NR 5 R 6 R 7 R 8 , R 5 , R 6 , R 7 and R 8 are the same or different and represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. 1 and M 2 the same or different, representing an L-valent metal, wherein the L-valent metal is a metal belonging to Group 1, Group 2, Group 4, Group 8, Group 11, Group 12, or Group 13 of the periodic table), and the acid treatment step makes the -SO3X 1 Change to -SO3H and / or make the above -COOZ 1 Changes to -COOH.

[0006] Patent Document 2 describes a coating composition for forming an antireflective film on a photoresist, which contains a fluorinated polymer (A1) having a carboxyl group, wherein the fluorinated polymer (A1) is represented by the formula (M-3):

[0007] -(M3)-(N3)-(M-3)

[0008] [Wherein, the structural unit M3 is from formula (5-1):

[0009] CH2=CFCF2-ORf 10 -COOH (5-1)

[0010] (Where Rf 10 The structural unit is a structural unit of a monomer represented by a divalent fluorinated alkylene group having 1 to 40 carbon atoms or a divalent fluorinated alkylene group having an ether bond having 2 to 100 carbon atoms); the structural unit N3 is a structural unit derived from a monomer copolymerizable with the fluorinated monomer of the above formula (5-1)], comprising 55 mol% to 100 mol% of the structural unit M3, 0 to 45 mol% of the structural unit N3, and having a number average molecular weight of 3.1×10 4 ~75.0×10 4 .

[0011] Prior art literature

[0012] Patent Literature

[0013] Patent Document 1: Japanese Patent Application Publication No. 2004-75979

[0014] Patent Document 2: Japanese Patent Application Publication No. 2009-122700 Summary of the invention

[0015] Problems to be solved by the invention

[0016] The present invention provides a method for producing a composition, which can efficiently remove low-molecular-weight substances, and also provides a composition with reduced low-molecular-weight substances.

[0017] Means for solving problems

[0018] The present invention relates to a method for producing a composition, characterized in that it comprises the following step A: subjecting a composition containing water and a fluorinated polymer to ultrafiltration, microfiltration or dialysis membrane treatment, or a combination thereof;

[0019] The fluorine-containing polymer is a polymer containing a structural unit M3 derived from a monomer represented by the general formula (1).

[0020] CX2=CY(-CZ2-O-Rf-A) (1)

[0021] (wherein, X is the same or different and is -H or -F, Y is -H, -F, alkyl or fluorinated alkyl, and Z is the same or different and is -H, -F, alkyl or fluorinated alkyl. Rf is a fluorinated alkylene group having 1 to 40 carbon atoms, or a fluorinated alkylene group having 2 to 100 carbon atoms and having an ether bond. A is -COOM, -SO3M, -OSO3M or -C(CF3)2OM (M is -H, a metal atom, -NR 7 4. an imidazolium which may be substituted, a pyridinium which may be substituted, or a phosphonium which may be substituted, R 7 is H or an organic group). wherein at least one of X, Y and Z contains a fluorine atom.

[0022] In the general formula (1), at least one of X is preferably -H.

[0023] In the general formula (1), both X are preferably -H.

[0024] In the general formula (1), Rf is preferably a fluorinated alkylene group having 1 to 10 carbon atoms or a fluorinated alkylene group having 2 to 12 carbon atoms and having an ether bond.

[0025] The structural unit M3 is preferably a structural unit (1A) based on a monomer represented by the following general formula (1A).

[0026] CH2=CF(-CF2-O-Rf-A)(1A)

[0027] (Wherein, Rf and A are the same as above.)

[0028] The structural unit M3 is preferably a structural unit (1a) based on a fluoroallyl ether compound represented by the following general formula (1a).

[0029] CX2=CFCF2-O-(CF(CF3)CF2O) n5 -CF(CF3)-A(1a)

[0030] (In the formula, each X is the same and represents F or H. n5 represents 0 or an integer of 1 to 10, and A has the same meaning as defined above.)

[0031] A is preferably -COOM.

[0032] M is preferably -H, -Na, -K, -Li or -NH4.

[0033] The fluorinated polymer is preferably a polymer in which the structural unit M3 accounts for 5 to 100 mol % of all polymerized units and the structural unit N3 derived from a monomer copolymerizable with the monomer represented by the general formula (1) accounts for 0 to 95 mol % of all polymerized units.

[0034] The structural unit N3 is preferably a structural unit derived from tetrafluoroethylene.

[0035] The fluorine-containing polymer preferably has a number average molecular weight of 0.5×10 4 ~75.0×10 4 of polymers.

[0036] The fluorine-containing polymer is preferably a polymer in which the ratio of hydrogen atoms bonded to carbon atoms being substituted with fluorine atoms is 50% or more, contains an ionic group, and has an ion exchange rate of 53 or less.

[0037] The fluorine-containing polymer is preferably a water-soluble polymer in which the ratio of hydrogen atoms bonded to carbon atoms being substituted with fluorine atoms is 50% or more.

[0038] The present invention also relates to a method for producing a composition, characterized in that it includes the following step A1: subjecting a composition comprising water and a polymer to ultrafiltration, microfiltration or dialysis membrane treatment, or a combination thereof, wherein the proportion of hydrogen atoms bonded to carbon atoms in the polymer being replaced by fluorine atoms is greater than 50%, and the polymer contains ionic groups and has an ion exchange rate of less than 53.

[0039] The polymer preferably has a number average molecular weight of 0.5×10 4 ~75.0×10 4 of polymers.

[0040] The above polymer is preferably a water-soluble polymer.

[0041] The present invention also relates to a method for producing a composition, characterized in that it includes the following step A2: subjecting a composition comprising water and a water-soluble polymer in which hydrogen atoms bonded to carbon atoms are replaced with fluorine atoms in a ratio of 50% or more to ultrafiltration, microfiltration or dialysis membrane treatment, or a combination thereof.

[0042] The ultrafiltration, microfiltration or dialysis membrane treatment is preferably performed at a temperature of 20° C. or higher.

[0043] The ultrafiltration preferably uses a molecular weight cut-off of 1.5×10 4 Da or more ultrafiltration membrane.

[0044] The present invention also relates to a composition, characterized in that it comprises water and a fluorine-containing polymer, wherein the fluorine-containing polymer is a polymer comprising a structural unit M3 derived from a monomer represented by the general formula (1),

[0045] CX2=CY(-CZ2-O-Rf-A) (1)

[0046] (wherein, X is the same or different and is -H or -F, Y is -H, -F, alkyl or fluorinated alkyl, and Z is the same or different and is -H, -F, alkyl or fluorinated alkyl. Rf is a fluorinated alkylene group having 1 to 40 carbon atoms, or a fluorinated alkylene group having 2 to 100 carbon atoms and having an ether bond. A is -COOM, -SO3M, -OSO3M or -C(CF3)2OM (M is -H, a metal atom, -NR 7 4. an imidazolium which may be substituted, a pyridinium which may be substituted, or a phosphonium which may be substituted, R 7 is H or an organic group). wherein at least one of X, Y and Z contains a fluorine atom.

[0047] In the composition, the content of the compound having a molecular weight of 700 to 3000 is 3.5% or less based on the fluorinated polymer.

[0048] The content of the compound having a molecular weight of 400 to 3000 is preferably 3.7% or less based on the fluorinated polymer.

[0049] The content of the compound having a molecular weight of 700 or more and less than 10,000 is preferably 5.0% or less based on the fluorinated polymer.

[0050] In the general formula (1), at least one of X is preferably -H.

[0051] In the general formula (1), both X are preferably -H.

[0052] In the general formula (1), Rf is preferably a fluorinated alkylene group having 1 to 10 carbon atoms or a fluorinated alkylene group having 2 to 12 carbon atoms and having an ether bond.

[0053] The structural unit M3 is preferably a structural unit (1A) based on a monomer represented by the following general formula (1A).

[0054] CH2=CF(-CF2-O-Rf-A)(1A)

[0055] (Wherein, Rf and A are the same as above.)

[0056] The structural unit M3 is preferably a structural unit (1a) based on a fluoroallyl ether compound represented by the following general formula (1a).

[0057] CX2=CFCF2-O-(CF(CF3)CF2O) n5 -CF(CF3)-A(1a)

[0058] (In the formula, each X is the same and represents F or H. n5 represents 0 or an integer of 1 to 10, and A has the same meaning as defined above.)

[0059] A is preferably -COOM.

[0060] M is preferably -H, -Na, -K, -Li or -NH4.

[0061] The fluorinated polymer is preferably a polymer in which the structural unit M3 accounts for 5 to 100 mol % of all polymerized units and the structural unit N3 derived from a monomer copolymerizable with the monomer represented by the general formula (1) accounts for 0 to 95 mol % of all polymerized units.

[0062] The fluorine-containing polymer preferably has a number average molecular weight of 0.5×10 4 ~75.0×10 4 of polymers.

[0063] In the above fluorine-containing polymer, it is preferred that the ratio of hydrogen atoms bonded to carbon atoms being substituted with fluorine atoms is 50% or more, the polymer contains an ionic group, and the ion exchange rate is 53 or less.

[0064] The fluorine-containing polymer is preferably a water-soluble polymer in which the ratio of hydrogen atoms bonded to carbon atoms being substituted with fluorine atoms is 50% or more.

[0065] The present invention also relates to a composition, characterized in that it contains water and a polymer, wherein the ratio of hydrogen atoms bonded to carbon atoms being replaced by fluorine atoms is 50% or more in the polymer, and the polymer contains ionic groups and has an ion exchange rate of 53 or less.

[0066] In the composition, the content of the compound having a molecular weight of 700 to 3000 is 3.5% or less based on the polymer.

[0067] The content of the compound having a molecular weight of 400 to 3000 is preferably 3.7% or less based on the polymer.

[0068] The content of the compound having a molecular weight of 700 or more and less than 10,000 is preferably 5.0% or less based on the polymer.

[0069] The polymer preferably has a number average molecular weight of 0.5×10 4 ~75.0×10 4 of polymers.

[0070] The above polymer is preferably a water-soluble polymer.

[0071] The present invention also relates to a composition characterized in that it contains water and a water-soluble polymer in which the hydrogen atoms bonded to carbon atoms are replaced by fluorine atoms in a ratio of 50% or more,

[0072] In the composition, the content of the compound having a molecular weight of 700 to 3000 is 3.5% or less based on the water-soluble polymer.

[0073] The content of the compound having a molecular weight of 400 to 3000 is preferably 3.7% or less based on the water-soluble polymer.

[0074] The content of the compound having a molecular weight of 700 or more and less than 10,000 is preferably 5.0% or less based on the water-soluble polymer.

[0075] The present invention also relates to a composition, characterized in that it comprises water and a fluorine-containing polymer, wherein the fluorine-containing polymer is a polymer comprising a structural unit M3 derived from a monomer represented by the general formula (1),

[0076] CX2=CY(-CZ2-O-Rf-A) (1)

[0077] (wherein, X is the same or different and is -H or -F, Y is -H, -F, alkyl or fluorinated alkyl, and Z is the same or different and is -H, -F, alkyl or fluorinated alkyl. Rf is a fluorinated alkylene group having 1 to 40 carbon atoms, or a fluorinated alkylene group having 2 to 100 carbon atoms and having an ether bond. A is -COOM, -SO3M, -OSO3M or -C(CF3)2OM (M is -H, a metal atom, -NR 7 4. an imidazolium which may be substituted, a pyridinium which may be substituted, or a phosphonium which may be substituted, R 7 is H or an organic group). wherein at least one of X, Y and Z contains a fluorine atom.

[0078] The content of dimers and trimers of monomers forming structural units constituting the fluorinated polymer is 2.0% or less based on the fluorinated polymer.

[0079] The fluorine-containing polymer is preferably a polymer in which the ratio of hydrogen atoms bonded to carbon atoms being substituted with fluorine atoms is 50% or more, contains an ionic group, and has an ion exchange rate of 53 or less.

[0080] The fluorine-containing polymer is preferably a water-soluble polymer in which the ratio of hydrogen atoms bonded to carbon atoms being substituted with fluorine atoms is 50% or more.

[0081] The present invention also relates to a composition, characterized in that it contains water and a polymer, in which the ratio of hydrogen atoms bonded to carbon atoms being replaced by fluorine atoms is 50% or more, and the polymer contains ionic groups and has an ion exchange rate of 53 or less.

[0082] The content of dimers and trimers of monomers forming structural units constituting the polymer is 2.0% or less based on the polymer.

[0083] The above polymer is preferably a water-soluble polymer.

[0084] The present invention also relates to a composition characterized in that it contains water and a water-soluble polymer in which the hydrogen atoms bonded to carbon atoms are replaced by fluorine atoms in a ratio of 50% or more,

[0085] The content of dimers and trimers of monomers forming structural units constituting the water-soluble polymer is 2.0% or less based on the water-soluble polymer.

[0086] The composition of the present invention is preferably a coating agent.

[0087] Effects of the Invention

[0088] The production method of the present invention can efficiently remove low molecular weight substances in the composition. DETAILED DESCRIPTION

[0089] Hereinafter, specific embodiments of the present invention will be described in detail, but the present invention is not limited to the above-mentioned embodiments.

[0090] The manufacturing method of the present invention relates to a method for manufacturing a composition (hereinafter also referred to as "the first manufacturing method of the present invention"), characterized in that it includes the following step A: subjecting a composition comprising water and a fluorinated polymer to ultrafiltration, microfiltration or dialysis membrane treatment, or a combination thereof, wherein the fluorinated polymer is a polymer comprising a structural unit M3 derived from a monomer represented by the general formula (1).

[0091] CX2=CY(-CZ2-O-Rf-A) (1)

[0092] (wherein, X is the same or different and is -H or -F, Y is -H, -F, alkyl or fluorinated alkyl, and Z is the same or different and is -H, -F, alkyl or fluorinated alkyl. Rf is a fluorinated alkylene group having 1 to 40 carbon atoms, or a fluorinated alkylene group having 2 to 100 carbon atoms and having an ether bond. A is -COOM, -SO3M, -OSO3M or -C(CF3)2OM (M is -H, a metal atom, -NR 7 4. an imidazolium which may be substituted, a pyridinium which may be substituted, or a phosphonium which may be substituted, R 7 is H or an organic group). wherein at least one of X, Y and Z contains a fluorine atom.

[0093] In the production of the above-mentioned fluorinated polymer, a composition of the fluorinated polymer containing low molecular weight bodies in addition to the above-mentioned fluorinated polymer is obtained. In the first production method of the present invention, it is found that ultrafiltration, microfiltration or dialysis membrane treatment is particularly effective for the composition containing the above-mentioned specific fluorinated polymer, and low molecular weight bodies (for example, compounds with a molecular weight of 700 to 3000, compounds with a molecular weight of 400 to 3000, compounds with a molecular weight of 700 to less than 10000, dimers and trimers of monomers forming structural units M3, dimers and trimers of monomers forming structural units constituting polymer α described later, dimers and trimers of monomers forming structural units constituting water-soluble polymers described later, etc.) can be removed efficiently, thereby completing the process.

[0094] The composition obtained by the first production method of the present invention may be an aqueous solution.

[0095] In the above general formula (1), X is -H or -F. Both Xs may be -H, or at least one of them may be -H. For example, one may be -F and the other may be -H, or both may be -H.

[0096] In the above general formula (1), Y is -H, -F, an alkyl group or a fluorine-containing alkyl group.

[0097] The alkyl group is an alkyl group not containing fluorine atoms and may have at least 1 carbon atom. The alkyl group may have preferably 6 or less carbon atoms, more preferably 4 or less carbon atoms, and even more preferably 3 or less carbon atoms.

[0098] The fluorine-containing alkyl group is an alkyl group containing at least one fluorine atom, and the number of carbon atoms may be 1 or more. The number of carbon atoms in the fluorine-containing alkyl group is preferably 6 or less, more preferably 4 or less, and even more preferably 3 or less.

[0099] As the above-mentioned Y, -H, -F or -CF3 is preferred, and -F is more preferred.

[0100] In the above general formula (1), Z is the same or different and is -H, -F, alkyl or fluoroalkyl.

[0101] The alkyl group is an alkyl group not containing fluorine atoms and may have at least 1 carbon atom. The alkyl group may have preferably 6 or less carbon atoms, more preferably 4 or less carbon atoms, and even more preferably 3 or less carbon atoms.

[0102] The fluorine-containing alkyl group is an alkyl group containing at least one fluorine atom, and the number of carbon atoms may be 1 or more. The number of carbon atoms in the fluorine-containing alkyl group is preferably 6 or less, more preferably 4 or less, and even more preferably 3 or less.

[0103] As the above-mentioned Z, -H, -F or -CF3 is preferred, and -F is more preferred.

[0104] In the above general formula (1), at least one of X, Y and Z preferably contains a fluorine atom. For example, X may be -H, and Y and Z may be -F.

[0105] In the general formula (1), Rf is a fluorinated alkylene group having 1 to 40 carbon atoms or a fluorinated alkylene group having an ether bond having 2 to 100 carbon atoms. The fluorinated alkylene group having an ether bond having 2 to 100 carbon atoms is an alkylene group having an ether bond between carbon atoms and not having an oxygen atom at the end.

[0106] The number of carbon atoms of the fluorinated alkylene group is preferably 2 or more. In addition, the number of carbon atoms of the fluorinated alkylene group is preferably 30 or less, more preferably 20 or less, and further preferably 10 or less. Examples of the fluorinated alkylene group include -CF2-, -CH2CF2-, -CF2CF2-, -CF2CH2-, -CF2CF2CH2-, -CF(CF3)-, -CF(CF3)CF2-, -CF(CF3)CH2-, etc. The fluorinated alkylene group is preferably a perfluoroalkylene group.

[0107] The number of carbon atoms in the fluorine-containing alkylene group having an ether bond is preferably 3 or more. The number of carbon atoms in the fluorine-containing alkylene group having an ether bond is preferably 60 or less, more preferably 30 or less, and even more preferably 12 or less.

[0108] As the fluorine-containing alkylene group having an ether bond, for example, the following formula is also preferred:

[0109] [Chemistry 1]

[0110]

[0111] (Where Z 1 F or CF3; Z 2 and Z 3 H or F; Z 4 is a 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).

[0112] Specific examples of the fluorinated alkylene group having an ether bond include -CF(CF3)CF2-O-CF(CF3)-, -(CF(CF3)CF2-O) n -CF(CF3)- (wherein n is an integer from 1 to 10), -CF(CF3)CF2-O-CF(CF3)CH2-, -(CF(CF3)CF2-O) n-CF(CF3)CH2- (wherein n is an integer of 1 to 10), -CH2CF2CF2O-CH2CF2CH2-, -CF2CF2CF2O-CF2CF2-, -CF2CF2CF2O-CF2CF2CH2-, -CF2CF2O-CF2-, -CF2CF2O-CF2CH2-, etc. The fluorine-containing alkylene group having an ether bond is preferably a perfluoroalkylene group.

[0113] In the above general formula (1), A is -COOM, -SO3M, -OSO3M or -C(CF3)2OM (M is -H, metal atom, -NR 7 4. an imidazolium which may be substituted, a pyridinium which may be substituted, or a phosphonium which may be substituted, R 7 is H or an organic group).

[0114] As R 7 , preferably H or C 1-10 An organic group, more preferably H or C 1-4 The organic group is preferably H or C 1-4 of alkyl.

[0115] Examples of the metal atom include alkali metals (Group 1) and alkaline earth metals (Group 2), and are preferably Na, K or Li.

[0116] As the above-mentioned M, -H, a metal atom or -NR 7 4, more preferably -H, alkali metal (Group 1), alkaline earth metal (Group 2) or -NR 7 4, further preferably -H, -Na, -K, -Li or -NH4, still more preferably -Na, -K or -NH4, particularly preferably -Na or -NH4, and most preferably -NH4.

[0117] The above-mentioned A is preferably -COOM or -SO3M, and more preferably -COOM.

[0118] As the structural unit M3, for example, there can be exemplified the following general formula (1a):

[0119] CX2=CFCF2-O-(CF(CF3)CF2O) n5 -CF(CF3)-A(1a)

[0120] The structural unit (1a) of a fluoroallyl ether compound represented by (wherein, each X is the same and represents F or H. n5 represents 0 or an integer of 1 to 10, and A has the same meaning as defined above) is a preferred structural unit.

[0121] In the general formula (1a), from the perspective of obtaining fluorinated polymer particles with a small primary particle size, the n5 is preferably 0 or an integer of 1 to 5, more preferably 0, 1 or 2, and further preferably 0 or 1. From the perspective of obtaining appropriate water solubility and surface activity, the A is preferably -COOM, and from the perspective of being less likely to remain as an impurity and improving the heat resistance of the obtained molded product, the M is preferably H or NH4.

[0122] The structural unit M3 is preferably a structural unit (1A) based on a monomer represented by the following general formula (1A).

[0123] CH2=CF(-CF2-O-Rf-A)(1A)

[0124] (Wherein, Rf and A are the same as above.)

[0125] Specific examples of the monomer represented by the general formula (1A) include the following:

[0126] [Chemistry 2]

[0127]

[0128] (Where Z 1 F or CF3; Z 2 and Z 3 H or F; Z 4 is H, F or CF3; p1+q1+r1 is an integer from 0 to 10; s1 is 0 or 1; t1 is an integer from 0 to 5, wherein Z 3 and Z 4 When all are H, p1+q1+r1+s1 is not 0; A is the same as defined above). More specifically, preferably,

[0129] [Chemistry 3]

[0130]

[0131] CH2=CFCF2OCH2CF2-A, CH2=CFCF2O(CH2CF2CF2O)CH2CF2-A,

[0132] CH2=CFCF2OCH2CF2CH2-A

[0133] CH2=CFCF2O(CH2CF2CF2O)CH2CF2CH2-A,

[0134] CH2=CFCF2OCF2CF2-A, CH2=CFCF2O(CF2CF2CF2O)CF2CF2—A,

[0135] CH2=CFCF2OCF2CF2CH2-A

[0136] CH2=CFCF2O(CF2CF2CF2O)CF2CF2CH2-A,

[0137] CH2=CFCF2OCF2A,CH2=CFCF2O(C2F2

[0138] CH2=CFCF2OCF2CH2-A,

[0139] CH2=CFCF2O(CF2CF2O)CF2CH2—A, etc., among which, preferably

[0140] [Chemistry 4]

[0141]

[0142] As the monomer represented by the above general formula (1A), A in formula (1A) is preferably -COOM, particularly preferably at least one selected from the group consisting of CH2=CFCF2OCF(CF3)COOM and CH2=CFCF2OCF(CF3)CF2OCF(CF3)COOM (wherein M has the same definition as above), more preferably CH2=CFCF2OCF(CF3)COOM.

[0143] Examples of the monomer represented by the general formula (1) include monomers represented by the following formulas.

[0144] CF2=CFCF2-O-Rf-A

[0145] (Wherein, Rf and A are the same as above.)

[0146] More specifically, we can cite

[0147] [Chemistry 5]

[0148] CF2=CFCF2OCF2CF2CF2—A,

[0149]

[0150] CF2=CFCF2OCF2CF2CF2CH2-A,

[0151] wait.

[0152] Furthermore, the structural unit M3 is also preferably a structural unit (1') based on a monomer represented by the following general formula (1').

[0153] CH2=CFCF2-ORf 10 -COOH(1')

[0154] (Where Rf 10 It is a fluorinated alkylene group having 1 to 40 carbon atoms or a fluorinated alkylene group having 2 to 100 carbon atoms and having an ether bond.

[0155] In the above general formula (1'), the above Rf 10 It is a fluorinated alkylene group having 1 to 40 carbon atoms or a fluorinated alkylene group having an ether bond having 2 to 100 carbon atoms. The fluorinated alkylene group having an ether bond having 2 to 100 carbon atoms is an alkylene group having an ether bond between carbon atoms and not having an oxygen atom at the end.

[0156] The number of carbon atoms of the fluorinated alkylene group is preferably 2 or more. In addition, it is preferably 30 or less, more preferably 20 or less, and further preferably 10 or less. Examples of the fluorinated alkylene group include -CF2-, -CH2CF2-, -CF2CF2-, -CF2CH2-, -CF2CF2CH2-, -CF(CF3)-, -CF(CF3)CF2-, -CF(CF3)CH2-, etc. The fluorinated alkylene group is preferably a perfluoroalkylene group.

[0157] The number of carbon atoms in the fluorine-containing alkylene group having an ether bond is preferably 3 or more. The number of carbon atoms in the fluorine-containing alkylene group having an ether bond is preferably 60 or less, more preferably 30 or less, and even more preferably 12 or less.

[0158] As the fluorine-containing alkylene group having an ether bond, for example, the following formula is also preferred:

[0159] [Chemistry 6]

[0160]

[0161] (Where Z 1 F or CF3; Z 2 and Z 3 H or F; Z 4 is a 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).

[0162] Specific examples of the fluorinated alkylene group having an ether bond include -CF(CF3)CF2-O-CF(CF3)-, -(CF(CF3)CF2-O) n -CF(CF3)- (wherein n is an integer from 1 to 10), -CF(CF3)CF2-O-CF(CF3)CH2-, -(CF(CF3)CF2-O) n-CF(CF3)CH2- (wherein n is an integer of 1 to 10), -CH2CF2CF2O-CH2CF2CH2-, -CF2CF2CF2O-CF2CF2-, -CF2CF2CF2O-CF2CF2CH2-, -CF2CF2O-CF2-, -CF2CF2O-CF2CH2-, etc. The fluorine-containing alkylene group having an ether bond is preferably a perfluoroalkylene group.

[0163] Specific examples of the monomer represented by the general formula (1') include the following:

[0164] [Chemistry 7]

[0165]

[0166] (Where Z 1 F or CF3; Z 2 and Z 3 H or F; Z 4 is H, F or CF3; p1+q1+r1 is an integer from 0 to 10; s1 is 0 or 1; t1 is an integer from 0 to 5, wherein Z 3 and Z 4 When all are H, p1+q1+r1+s1 is not 0). More specifically, preferably,

[0167] [Chemistry 8]

[0168]

[0169] CH2=CFCF2OCH2CF2-COOH

[0170] CH2=CFCF2O(CH2CF2CF2O)CH2CF2-COOH,

[0171] CH2=CFCF2OCH2CF2CH2-COOH

[0172] CH2=CFCF2O(CH2CF2CF2O)CH2CF2CH2-COOH

[0173] CH2=CFCF2OCF2CF2-COOH,

[0174] CH2=CFCF2O(CF2CF2CF2O)CF2CF2-COOH

[0175] CH2=CFCF2OCF2CF2CH2-COOH

[0176] CH2=CFCF2O(CF2CF2CF2O)CF2CF2CH2—COOH

[0177] CH2=CFCF2OCF2-COOH

[0178] CH2=CFCF2O(CF2CF2O)CF2-COOH

[0179] CH2=CFCF2OCF2CH2-COOH

[0180] CH2=CFCF2O(CF2CF2O)CF2CH2-COOH, etc., among which, preferably

[0181] [Chemistry 9]

[0182]

[0183] Examples of the monomer represented by the general formula (1') include the following general formula (1a'):

[0184] CH2=CFCF2-O-(CF(CF3)CF2O) n5 -CF(CF3)-COOH(1a')

[0185] A preferred substance is a fluoroallyl ether compound represented by (wherein n5 represents 0 or an integer of 1 to 10).

[0186] In the above formula (1a′), the above n5 is preferably 0 or an integer of 1 to 5, more preferably 0, 1 or 2, and even more preferably 0 or 1.

[0187] The monomer represented by the general formula (1a′) is particularly preferably at least one selected from the group consisting of CH2═CFCF2OCF(CF3)COOH and CH2═CFCF2OCF(CF3)CF2OCF(CF3)COOH, and more preferably CH2═CFCF2OCF(CF3)COOH.

[0188] The fluorinated polymer may be a homopolymer consisting only of the structural unit M3, or a copolymer comprising the structural unit M3 and a structural unit N3 derived from a monomer copolymerizable with the monomer represented by the general formula (1). From the perspective of solubility in the polymerization medium, a homopolymer consisting only of the structural unit M3 is preferred. The structural unit M3 may be the same or different each time it appears, and the fluorinated polymer may contain structural units M3 derived from two or more different monomers represented by the general formula (1).

[0189] As the monomer copolymerizable with the monomer represented by the general formula (1), a fluorinated olefinic monomer having 2 or 3 carbon atoms is preferred, and examples thereof include CF2=CF2, CF2=CFCl, CH2=CF2, CFH=CH2, CFH=CF2, CF2=CFCF3, CH2=CFCF3, CH2=CHCF3, CHF=CHCF3 (E-isomer), CHF=CHCF3 (Z-isomer), etc. Among them, from the perspective of good copolymerizability, at least one selected from the group consisting of tetrafluoroethylene (CF2=CF2), trifluorochloroethylene (CF2=CFCl) and vinylidene fluoride (CH2=CF2) is preferred, and tetrafluoroethylene is more preferred. Therefore, the structural unit N3 is preferably a structural unit derived from tetrafluoroethylene. The structural unit N3 may be the same or different each time it appears, and the fluorinated polymer may contain structural units N3 derived from two or more different monomers copolymerizable with the monomer represented by the general formula (1).

[0190] As the monomer copolymerizable with the monomer represented by the above general formula (1), the following formula (n1-2) can also be mentioned:

[0191] [Chemistry 10]

[0192]

[0193] (Where X 1 , X 2 Same or different, H or F; X 3 is H, F, Cl, CH3 or CF3; X 4 , X 5 are the same or different, and are H or F; a and c are the same or different, and are 0 or 1. 3 The monomer is a fluorinated alkyl group having 1 to 40 carbon atoms or a fluorinated alkyl group having an ether bond having 2 to 100 carbon atoms).

[0194] Specifically, CH2=CFCF2-O-Rf is preferably used. 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.

[0195] As the other monomers, the following may also be mentioned:

[0196] [Chemistry 11]

[0197]

[0198] (Where X 9 is H, F or CH3; Rf 4 is a fluorinated acrylate monomer represented by a fluorinated alkyl group having 1 to 40 carbon atoms or a fluorinated alkyl group having an ether bond having 2 to 100 carbon atoms. 4 The basis can be cited

[0199] [Chemistry 12]

[0200]

[0201] (Where Z 8 is H, F or Cl; d1 is an integer from 1 to 4; e1 is an integer from 1 to 10)

[0202] -CH(CF3)2,

[0203]

[0204] (wherein e2 is an integer from 1 to 5)

[0205]

[0206] (wherein, d3 is an integer from 1 to 4; e3 is an integer from 1 to 10), etc.

[0207] Examples of monomers copolymerizable with the monomer represented by the general formula (1) include the following:

[0208] CH2=CHO-Rf 5 (n2-2)

[0209] (Where Rf 5 The fluorine-containing vinyl ether is a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having an ether bond having 2 to 100 carbon atoms.

[0210] Specifically, preferred examples of the monomer of formula (n2-2) include

[0211] [Chemistry 13]

[0212]

[0213] (Where Z 9 is H or F; e4 is an integer from 1 to 10)

[0214]

[0215] (wherein e5 is an integer from 1 to 10)

[0216]

[0217] (wherein e6 is an integer from 1 to 10) etc.

[0218] More specifically, we can cite

[0219] [Chemistry 14]

[0220] CH2=CHOCH2CF2CF2H、

[0221]

[0222] CH2=CHOCH2CF2CF3、

[0223] CH2=CHOCH2CF3,

[0224]

[0225] wait.

[0226] In addition, formula (n2-3) can also be cited:

[0227] CH2=CHCH2O-Rf 6 (n2-3)

[0228] (Where Rf 6 is a fluorinated allyl ether represented by a fluorinated alkyl group having 1 to 40 carbon atoms or a fluorinated alkyl group having an ether bond having 2 to 100 carbon atoms, formula (n2-4):

[0229] CH2=CH-Rf 7 (n2-4)

[0230] (Where Rf 7 The fluorine-containing vinyl monomer is represented by a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having an ether bond having 2 to 100 carbon atoms.

[0231] Specific examples of the monomers represented by the above formulae (n2-3) and (n2-4) include:

[0232] [Chemistry 15]

[0233] CH2=CHCH2OCH2CF2CF2H、

[0234]

[0235] CH2=CHCH2OCH2CF2CF3、

[0236] CH2=CHCH2OCH2CF3,

[0237]

[0238]

[0239]

[0240] Etc. monomers.

[0241] In the above-mentioned fluorinated polymer, the content of the structural unit M3 is preferably 1.0 mol% or more, more preferably 3.0 mol% or more, further preferably 5.0 mol% or more, further more preferably 10 mol% or more, particularly preferably 20 mol% or more, and particularly preferably 30 mol% or more, more preferably 40 mol% or more, further preferably 60 mol% or more, further more preferably 80 mol% or more, particularly preferably 90 mol% or more, particularly preferably substantially 100 mol%, and most preferably consisting only of the structural unit M3.

[0242] In the above-mentioned fluorinated polymer, the content of the structural unit N3 is preferably 99.0 mol% or less, more preferably 97.0 mol% or less, further preferably 95.0 mol% or less, still more preferably 90 mol% or less, particularly preferably 80 mol% or less, and particularly preferably 70 mol% or less, with respect to all polymerized units. It is more preferably 60 mol% or less, further preferably 40 mol% or less, still more preferably 20 mol% or less, particularly preferably 10 mol% or less, particularly preferably substantially 0 mol%, and particularly preferably no structural unit N3 is contained.

[0243] In the above fluorinated polymer, the structural unit M3 is derived from the following formula (1a):

[0244] CH2=CFCF2-O-(CF(CF3)CF2O)n5-CF(CF3)-COOH(1a)

[0245] It is one of the particularly preferred embodiments that the structural unit N3 is a structural unit derived from tetrafluoroethylene, wherein the structural unit N3 is a structural unit of a fluoroallyl ether compound represented by (wherein n5 represents 0 or an integer of 1 to 10).

[0246] In the above-mentioned fluorinated polymer, the content of the structural unit derived from the fluoroallyl ether compound represented by formula (1a) is preferably 10 mol% or more, more preferably 20 mol% or more, further preferably 30 mol% or more, even more preferably 40 mol% or more, particularly preferably 60 mol% or more, particularly preferably 80 mol% or more, particularly preferably 90 mol% or more, and particularly preferably substantially 100 mol% relative to all polymerized units.

[0247] In addition, in the above-mentioned fluorinated polymer, the content of the structural unit derived from tetrafluoroethylene is preferably 90 mol% or less, more preferably 80 mol% or less, further preferably 70 mol% or less, still more preferably 60 mol% or less, particularly preferably 40 mol% or less, particularly more preferably 20 mol% or less, particularly preferably 10 mol% or less, and particularly preferably substantially 0 mol%.

[0248] The number average molecular weight of the fluorinated polymer is preferably 0.1×10 4 More preferably, 0.2×10 4 More preferably, 0.3×10 4 More preferably, 0.4×10 4 More than 0.5×10 4 More than 1.0×10 4 Above, particularly preferably 3.0×10 4 More than, most preferably 3.1×10 4 In addition, it is preferably 75.0×10 4 Less than, more preferably 50.0×10 4 Below, more preferably 40.0×10 4 Below, especially preferably 30.0×10 4 Below, particularly preferably 20.0×10 4 the following.

[0249] If the number average molecular weight is too low, the dispersibility (the property of stably dispersing other components) is reduced, and it may not be used as a dispersant. If the number average molecular weight is too high, the viscosity is increased, and the handling may become complicated.

[0250] The weight average molecular weight of the fluorine-containing polymer is preferably 0.2×10 4 More preferably, 0.4×10 4 More preferably, 0.6×10 4 More preferably, 0.8×10 4 More than 1.0×10 4 More preferably, 5.0×10 4 More preferably, 10.0×10 4 More than 15.0×10 4 Above, particularly preferably 20.0×10 4 More than, most preferably 25.0×10 4 In addition, it is preferably 150.0×10 4 Less than, more preferably 100.0×10 4Below, more preferably 60.0×10 4 Below, particularly preferably 50.0×10 4 Below, especially preferably 40.0×10 4 the following.

[0251] The above number average molecular weight and weight average molecular weight are values ​​calculated by gel permeation chromatography (GPC) using monodisperse polyethylene oxide (PEO) and polyethylene glycol (PEG) manufactured by Tosoh and Agilent as standards for molecular weight. In addition, when it is impossible to measure by GPC, the number average molecular weight of the fluoropolymer can be obtained based on the correlation between the number average molecular weight calculated by the number of terminal groups obtained by NMR, FT-IR, etc. and the melt flow rate. The melt flow rate can be measured according to JIS K 7210.

[0252] In the above-mentioned fluorine-containing polymer, the ratio of hydrogen atoms bonded to carbon atoms replaced by fluorine atoms is preferably 50% or more. "The ratio of hydrogen atoms bonded to carbon atoms replaced by fluorine atoms" is calculated as the ratio of the number of fluorine atoms to the total number of hydrogen atoms bonded to carbon atoms and halogen atoms (including fluorine atoms) bonded to carbon atoms. The ratio of hydrogen atoms bonded to carbon atoms in the above-mentioned fluorine-containing polymer replaced by fluorine atoms is not particularly limited, but is more preferably 80% or more, further preferably 90% or more, particularly preferably 95% or more, and most preferably 100%.

[0253] The above-mentioned fluorine-containing polymer preferably contains an ionic group.

[0254] The fluorinated polymer preferably has 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 groups. For the purpose of determining IXR, precursor groups that become ionic by hydrolysis (e.g., -SO2F) are not considered ionic groups.

[0255] The IXR is preferably 0.5 or more, more preferably 1 or more, further preferably 3 or more, still more preferably 4 or more, particularly preferably 5 or more, and particularly preferably 8 or more. The IXR is more preferably 43 or less, further preferably 33 or less, and particularly preferably 23 or less.

[0256] In the above fluorine-containing polymer, the ionic groups are typically distributed along the polymer main chain. The above fluorine-containing polymer preferably comprises a polymer main chain and repetitive side chains bonded to the main chain, and the side chains have ionic groups.

[0257] The fluoropolymer preferably comprises an ionic group having a pKa of less than 10, more preferably less than 7. The ionic group of the fluoropolymer is preferably selected from the group consisting of sulfonates, carboxylates, phosphonates and phosphates.

[0258] The terms "sulfonate, carboxylate, phosphonate and phosphate" refer to the respective salts or the respective acids capable of forming salts. In the case of using a salt, it is preferably an alkali metal salt or an ammonium salt. The preferred ionic group is a sulfonate group.

[0259] The fluorinated polymer is preferably a water-soluble polymer. "Water-soluble" refers to the property of being easily dissolved or dispersed in an aqueous medium. For example, a water-soluble polymer cannot have its particle size measured by a dynamic light scattering method (DLS). On the other hand, for example, a water-insoluble polymer can have its particle size measured by a dynamic light scattering method (DLS).

[0260] The above-mentioned fluorine-containing polymer can be produced by a conventionally known method except for using the above-mentioned monomers.

[0261] In the composition containing water and the fluorinated polymer, the concentration of the fluorinated polymer is not particularly limited, and may be, for example, 0.1% by mass to 20% by mass.

[0262] Since the removal efficiency of low molecular weight bodies is more efficient, the concentration of the above-mentioned fluorinated polymer in the composition is preferably 18.0 mass % or less. More preferably, it is 15.0 mass % or less, further preferably 12.0 mass % or less, and particularly preferably 10.0 mass % or less. By making the concentration of the above-mentioned fluorinated polymer within the above-mentioned range, low molecular weight bodies can be removed more efficiently. The concentration of the above-mentioned fluorinated polymer is preferably 0.5 mass % or more, more preferably 1.0 mass % or more, further preferably 1.2 mass % or more, and particularly preferably 1.5 mass % or more.

[0263] The composition comprising water and the above-mentioned fluorinated polymer may contain a single fluorinated polymer or may contain two or more different fluorinated polymers.

[0264] The pH of the composition containing water and the fluorinated polymer is preferably 0 to 11, more preferably 0.5 to 8.0. The pH can be adjusted by a pH adjuster. The pH adjuster may be an acid or a base, such as phosphate, sodium hydroxide, potassium hydroxide, ammonia water, etc.

[0265] The first production method of the present invention also preferably includes, before step A, a step of adjusting the pH of the composition containing water and the fluorinated polymer to from 1.0 to 7.0.

[0266] The composition containing water and the above-mentioned fluorinated polymer can be obtained, for example, by polymerizing the monomer represented by the general formula (1). The first manufacturing method of the present invention includes a step of polymerizing the monomer represented by the general formula (1) (hereinafter also referred to as "polymerization step"), which is also one of the preferred embodiments. The above-mentioned polymerization step is preferably carried out in an aqueous medium. That is, the first manufacturing method of the present invention also preferably includes the following step: polymerizing the monomer represented by the general formula (1) in an aqueous medium, thereby obtaining a composition containing water and a fluorinated polymer.

[0267] The polymerization step is not limited as long as a composition containing water and a fluorinated polymer can be obtained, and a known method can be employed.

[0268] The composition comprising water and the fluorinated polymer may be a polymerized composition obtained by polymerization, a diluted or concentrated polymerized composition obtained by polymerization, or a dispersion stabilization treatment. In order to smoothly perform ultrafiltration, microfiltration or dialysis membrane treatment, it is also preferred to adjust the viscosity of the composition comprising the fluorinated polymer by these treatments.

[0269] Since ultrafiltration, microfiltration or dialysis membrane treatment proceeds smoothly, the viscosity of the composition containing water and the fluorinated polymer used in step A is preferably 25 mPa·s or less. The viscosity of the composition can be adjusted, for example, by a method of adjusting the number average molecular weight of the fluorinated polymer, a method of adjusting the concentration of the fluorinated polymer in the composition, a method of adjusting the temperature of the composition, and the like.

[0270] The above-mentioned polymerization usually generates low molecular weight products as by-products. In the first production method of the present invention, the low molecular weight products can be removed by subjecting the composition containing water and the fluorinated polymer to a treatment such as ultrafiltration.

[0271] The composition comprising water and the fluorinated polymer used in step A may contain low molecular weight substances. For example, the content of the low molecular weight substances is preferably more than 5.0%, more preferably more than 5.5%, further preferably more than 6.0%, or more than 2.0% based on the fluorinated polymer.

[0272] As low molecular weight bodies, for example, compounds having a molecular weight of 700 to 3000, compounds having a molecular weight of 400 to 3000, compounds having a molecular weight of 700 to less than 10000, dimers and trimers of monomers forming structural units M3, dimers and trimers of monomers forming structural units constituting polymer α described later, dimers and trimers of monomers forming structural units constituting water-soluble polymers described later, etc. can be cited.

[0273] The content of the low molecular weight body is a value calculated from the peak area of ​​GPC and / or a value calculated by measurement using liquid chromatography-mass spectrometry (LC / MS / MS).

[0274] The ultrafiltration or microfiltration may be carried out in a cross-flow manner or a dead-end manner without limitation, but the cross-flow manner is preferred from the viewpoint of reducing membrane clogging.

[0275] The ultrafiltration can be performed using an ultrafiltration membrane. For example, the ultrafiltration can be performed using an ultrafiltration device having an ultrafiltration membrane, and can be performed using centrifugal ultrafiltration, intermittent ultrafiltration, circulating ultrafiltration, and the like.

[0276] The molecular weight cut-off of the above ultrafiltration membrane is usually 0.1×10 4 ~30×10 4 The lower limit of the molecular weight cutoff of the ultrafiltration membrane is preferably 0.3×10 4 Da or above, 0.5×10 4 Da or above, 1.0×10 4 Large or above, 1.5×10 4 Da or above, 2.0×10 4 Large or above, 3.0×10 4 Large or above, 5.0×10 4 Large or above, 8.0×10 4 Big or above.

[0277] In addition, from the perspective of reducing low molecular weight products, the molecular weight cut-off is preferably 20×10 4 Da or less, more preferably 10×10 4 Da below.

[0278] The molecular weight cutoff of the ultrafiltration membrane may be, for example, the molecular weight at which 90% of polystyrene having a known weight average molecular weight is rejected when passing through the membrane. The quantitative determination of polystyrene can be performed using gel permeation chromatography.

[0279] In particular, in order to efficiently remove compounds with a molecular weight of 700 to 3000, compounds with a molecular weight of 400 to 3000, compounds with a molecular weight of 700 to less than 10000, etc. from the composition containing the fluorinated polymer, it is preferred to subject the composition containing the fluorinated polymer to ultrafiltration. The molecular weight cutoff of the ultrafiltration membrane used in this case is preferably 1.0×10 4 Da or more, more preferably 1.5×10 4 Da or more, preferably 20.0×10 4 Da or less, more preferably 10.0×104 Da below.

[0280] The shape of the ultrafiltration membrane may be any known shape, but is not limited thereto, and includes, for example, a hollow fiber type, a flat membrane type, a spiral type, a tubular type, etc. From the viewpoint of suppressing clogging, a hollow fiber type is preferred.

[0281] The inner diameter of the hollow fiber ultrafiltration membrane is not limited, and may be, for example, 0.1 mm to 2 mm, preferably 0.8 mm to 1.4 mm.

[0282] The length of the hollow fiber ultrafiltration membrane is not limited, and may be, for example, 0.05 m to 3 m, preferably 0.05 m to 2 m.

[0283] The material of the ultrafiltration membrane is not particularly limited, and examples thereof include organic materials such as cellulose, cellulose ester, polysulfone, sulfonated polysulfone, polyethersulfone, sulfonated polyethersulfone, chlorinated polyethylene, polypropylene, polyolefin, polyvinyl alcohol, polymethyl methacrylate, polyacrylonitrile, polyvinylidene fluoride, polytetrafluoroethylene, metals such as stainless steel, and inorganic materials such as ceramics.

[0284] The material of the ultrafiltration membrane is preferably an organic material, more preferably chlorinated polyethylene, polypropylene, polyvinylidene fluoride, polytetrafluoroethylene, polyacrylonitrile, polysulfone or polyethersulfone, further preferably polyacrylonitrile or polyvinylidene fluoride.

[0285] Specific examples of the ultrafiltration membrane include G-5, G-10, G-20, G-50, PW, and HWS UF manufactured by DESAL; 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 manufactured by KOCH; SPE1, SPE3, SPE5, SPE10, SPE30, SPV5, SPV50, and SOW30 manufactured by Synder; Microza (registered trademark) UF series manufactured by Asahi Kasei Corporation; and NTR7410 manufactured by Nitto Denko Corporation.

[0286] From the aspect of reducing low molecular weight bodies, the ultrafiltration is preferably carried out at a pressure of 0.01 MPa or more, more preferably 0.03 MPa or more, and further preferably 0.05 MPa or more. In addition, from the aspect of pressure resistance, the pressure is preferably 0.5 MPa or less, more preferably 0.25 MPa or less, and further preferably 0.2 MPa or less.

[0287] From the perspective of reducing low molecular weight entities, the above 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 is preferably carried out at a flow rate of 5000 mL / min or less, more preferably at a flow rate of 1000 mL / min or less.

[0288] The microfiltration can be performed using a microfiltration membrane. The microfiltration membrane generally has an average pore size of 0.05 μm to 1.0 μm.

[0289] For the above-mentioned microfiltration membrane, since low molecular weight bodies can be efficiently reduced, the average pore diameter is preferably 0.1 μm or more. It is more preferably 0.075 μm or more, and further preferably 0.1 μm or more. In addition, the average pore diameter is preferably 1.00 μm or less. The average pore diameter is more preferably 0.50 μm or less, and further preferably 0.25 μm or less.

[0290] The average pore size of the microfiltration membrane can be measured according to ASTM F316-03 (bubble point method).

[0291] The shape of the microfiltration membrane may be any known shape, but is not limited thereto, and includes, for example, a hollow fiber type, a flat membrane type, a spiral type, a tubular type, etc. From the viewpoint of suppressing clogging, a hollow fiber type is preferred.

[0292] The inner diameter of the hollow fiber microfiltration membrane is not limited, and may be, for example, 0.1 mm to 2 mm, preferably 0.8 mm to 1.4 mm.

[0293] The length of the hollow fiber microfiltration membrane is not limited, and may be, for example, 0.05 m to 3 m, preferably 0.05 m to 2 m.

[0294] As the material of the microfiltration membrane, for example, cellulose, aromatic polyamide, polyvinyl alcohol, polysulfone, polyethersulfone, polyvinylidene fluoride, polyethylene, polyacrylonitrile, polypropylene, polycarbonate, polytetrafluoroethylene, ceramics, metals, etc. Among them, aromatic polyamide, polyvinyl alcohol, polysulfone, polyvinylidene fluoride, polyethylene, polyacrylonitrile, polypropylene, polycarbonate or polytetrafluoroethylene is preferred, and polyacrylonitrile or polyvinylidene fluoride is particularly preferred.

[0295] Specific examples of the microfiltration membrane include Cefilt manufactured by NGK INSULATORS, LTD.; Microza U series and Microza P series manufactured by Asahi Kasei Corporation; POREFLON SPMW, POREFLON OPM, and POREFLON PM manufactured by Sumitomo Electric Industries, Ltd.; Trefil manufactured by Toray Industries, Ltd.; NADIR MP005 and NADIR MV020 manufactured by MICRODYN-NADIR; and X-flow manufactured by Norit Corporation.

[0296] From the aspect of reducing low molecular weight bodies, the microfiltration is preferably carried out at a pressure of 0.01 MPa or more, more preferably 0.03 MPa or more, and even more preferably 0.05 MPa or more. In addition, from the aspect of pressure resistance, the pressure is preferably 0.5 MPa or less, more preferably 0.25 MPa or less, and even more preferably 0.2 MPa or less.

[0297] From the perspective of reducing low molecular weight entities, the above microfiltration 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 is preferably carried out at a flow rate of 5000 mL / min or less, more preferably at a flow rate of 1000 mL / min or less.

[0298] The above-mentioned dialysis membrane treatment is performed using a dialysis membrane. The dialysis membrane usually has a dialysis capacity of 0.05×10 4 ~100×10 4 Da molecular weight cut-off.

[0299] The molecular weight cut-off of the dialysis membrane is preferably 0.3×10 4 The molecular weight cut-off is more preferably 0.5×10 4 Da or more, more preferably 1.0×10 4 Da or more, more preferably 1.5×10 4 Da or more, particularly preferably 2.0×10 4 Da or more, particularly preferably 3.0×10 4 Da or more, most preferably 5.0×10 4 The above molecular weight cut-off can also be 8.0×10 4 Big or above.

[0300] In addition, from the perspective of reducing coloration, the molecular weight cut-off is preferably 20×10 4 Da or less, more preferably 10×10 4 Da below.

[0301] The molecular weight cut-off of the dialysis membrane can be measured, for example, using the same method as for the ultrafiltration membrane.

[0302] In particular, in order to efficiently remove dimers and trimers of monomers forming structural unit M3, dimers and trimers of monomers forming structural units constituting polymer α described later, dimers and trimers of monomers forming structural units constituting water-soluble polymers described later, etc. from the composition containing the fluorinated polymer, it is preferred to subject the composition containing the fluorinated polymer to dialysis membrane treatment. The molecular weight cutoff of the dialysis membrane used in this case is preferably 0.3×10 4 Da or more, more preferably 0.5×10 4 Da or more, preferably 8.0×10 4 Da or less, more preferably 5.0×10 4 Da below.

[0303] The material of the dialysis membrane is not particularly limited, and examples thereof include polyethylene, cellulose, polyacrylonitrile, polymethyl methacrylate, ethylene vinyl alcohol copolymer, polysulfone, polyamide, and polyester-based polymer alloys.

[0304] Specific examples of the dialysis membrane include Spectra / Por (registered trademark) Float-A-Lyzer, Tube-A-Lyzer, Dialysis tubing, 6Dialysis tubing, and 7Dialysis tubing manufactured by Spectrum Laboratories.

[0305] The ultrafiltration, microfiltration or dialysis membrane treatment is preferably performed at a temperature of 10°C or higher. It is more preferably 15°C or higher, further preferably 20°C or higher, and particularly preferably 30°C or higher. By setting the temperature within the above range, low molecular weight substances can be reduced more efficiently. The temperature is preferably 90°C or lower, more preferably 80°C or lower, further preferably 70°C or lower, and particularly preferably 60°C or lower.

[0306] In the first production method of the present invention, water may be added to the composition comprising water and the fluorinated polymer, or a pH adjuster may be added to adjust the pH of the composition comprising water and the fluorinated polymer while performing ultrafiltration, microfiltration or dialysis membrane treatment.

[0307] Therefore, the step A may include the step of adding water to the composition comprising water and the fluorinated polymer. The water may be added in stages or continuously. In addition, the step A may include the step of adding a pH adjuster to the composition comprising water and the fluorinated polymer.

[0308] Among the above-mentioned ultrafiltration, microfiltration or dialysis membrane treatment, ultrafiltration or microfiltration is preferred, and ultrafiltration is more preferred.

[0309] The endpoint of the ultrafiltration, microfiltration or dialysis membrane treatment may be appropriately determined and is not limited.

[0310] In order to improve the durability of the filtration membrane, the ultrafiltration, microfiltration or dialysis membrane treatment may be backwashed with water about once every 1 to 24 hours during the filtration step.

[0311] According to the first production method of the present invention, there can be obtained a composition comprising the above-mentioned fluorinated polymer and having a reduced content of low-molecular-weight substances.

[0312] The present invention also provides a method for manufacturing a composition (hereinafter also referred to as "the second manufacturing method of the present invention"), characterized in that it includes the following step A1: subjecting a composition comprising water and a polymer (hereinafter also referred to as "polymer α") to ultrafiltration, microfiltration or dialysis membrane treatment, or a combination thereof, wherein the proportion of hydrogen atoms bonded to carbon atoms in the polymer being replaced by fluorine atoms is greater than 50%, and the polymer contains ionic groups and has an ion exchange rate of less than 53.

[0313] The composition obtained by the second production method of the present invention may be an aqueous solution.

[0314] In the second manufacturing method of the present invention, the above-mentioned step A1 adopts the same method as the first manufacturing method of the present invention except that a composition containing polymer α is used. In the above-mentioned polymer α, the proportion of hydrogen atoms bonded to carbon atoms replaced by fluorine atoms is greater than 50%, and the polymer α contains ionic groups and has an ion exchange rate of less than 53.

[0315] The “ratio of hydrogen atoms bonded to carbon atoms replaced by fluorine atoms” is determined as the ratio of the number of fluorine atoms to the total number of hydrogen atoms bonded to carbon atoms and halogen atoms (including fluorine atoms) bonded to carbon atoms.

[0316] The polymer α is not particularly limited. Among the fluorinated polymers, a polymer in which the hydrogen atoms bonded to carbon atoms are replaced by fluorine atoms in a ratio of 50% or more, containing ionic groups (anionic groups) and having an ion exchange rate of 53 or less can be used. A polymer other than the fluorinated polymers mentioned above in which the hydrogen atoms bonded to carbon atoms are replaced by fluorine atoms in a ratio of 50% or more, containing ionic groups (anionic groups) and having an ion exchange rate of 53 or less can also be used.

[0317] Examples of the polymer α include polymers containing a structural unit (I) based on a monomer represented by the general formula (I). The polymer α preferably contains two or more structural units (I).

[0318] CX 1 X 3 =CX 2 R-CZ 1 Z 2 -A 0 (I)

[0319] (Where X 1 and X 3 Each independently is F, Cl, H or CF3; X 2 is H, F, alkyl or fluorinated alkyl; A 0 is an anionic group; R is a connecting group; Z 1 and Z 2 Each is independently H, F, alkyl or fluorinated alkyl. )

[0320] As X 2 , preferably F, Cl, H or CF3. 1 and Z 2 , preferably F or CF3, and more preferably one is F and the other is CF3.

[0321] In the present invention, the anionic groups include, in addition to anionic groups such as sulfate groups and carboxylate groups, acid groups such as -COOH and acid salt groups such as -COONH4 that provide anionic groups. As anionic groups, sulfate groups, carboxylate groups, phosphate groups, phosphonate groups, sulfonate groups, or -C(CF3)2OM (wherein M is -H, a metal atom, -NR 7 4. an imidazolium which may be substituted, a pyridinium which may be substituted, or a phosphonium which may be substituted, R 7 is H or an organic group).

[0322] The polymer α may contain only the structural unit (I) based on one monomer represented by the general formula (I), or may contain the structural unit (I) based on two or more monomers represented by the general formula (I).

[0323] R is a linking group. In the present invention, "linking group" refers to a divalent linking group. The linking group may be a single bond, preferably contains at least one carbon atom, and the number of carbon atoms may be 2 or more, 4 or more, 8 or more, 10 or more, or 20 or more. The upper limit is not limited, for example, it may be 100 or less, or 50 or less.

[0324] The linking group may be a chain or branched, cyclic or acyclic structure, saturated or unsaturated, substituted or unsubstituted, and may contain one or more heteroatoms selected from the group consisting of sulfur, oxygen and nitrogen as desired, and may contain one or more functional groups selected from the group consisting of ester, amide, sulfonamide, carbonyl, carbonate, carbamate, urea and carbamate as desired. The above linking group does not contain carbon atoms and may be a chain heteroatom such as oxygen, sulfur or nitrogen.

[0325] R is preferably a chain hetero atom such as oxygen, sulfur, or nitrogen, or a divalent organic group.

[0326] When R is a divalent organic group, the hydrogen atom bonded to the carbon atom may be substituted by a halogen other than fluorine, such as chlorine, and may or may not contain a double bond. In addition, R may be either a chain or a branched chain, or may be either a cyclic or acyclic. In addition, R may contain a functional group (e.g., an ester, an ether, a ketone, an amine, a halide, etc.).

[0327] In addition, R may be a non-fluorinated divalent organic group, or a partially fluorinated or perfluorinated divalent organic group.

[0328] R may be, for example: a hydrocarbon group having no fluorine atom bonded to a carbon atom; a hydrocarbon group having a portion of hydrogen atoms bonded to a carbon atom substituted by fluorine atoms; or a hydrocarbon group having all hydrogen atoms bonded to a carbon atom substituted by fluorine atoms, which may contain oxygen atoms, double bonds, or functional groups.

[0329] R is preferably a hydrocarbon group having 1 to 100 carbon atoms which may contain an ether bond, and a part or all of hydrogen atoms bonded to carbon atoms in the hydrocarbon group may be substituted with fluorine.

[0330] As R, it is preferably selected from -(CH2) a -、-(CF2) a -、-O-(CF2) a -、-(CF2) a -O-(CF2) b -、-O(CF2) a -O-(CF2) b -、-(CF2) a -[O-(CF2) b ] c -、-O(CF2) a -[O-(CF2) b ] c -、-[(CF2) a -O] b -[(CF2) c -O] d -、-O[(CF2)a -O] b -[(CF2) c -O] d -、-O-[CF2CF(CF3)O] a -(CF2) b -、-[CF2CF(CF3)O] a -, -[CF(CF3)CF2O] a -、-(CF2) a -O-[CF(CF3)CF2O] a -、-(CF2) a -O-[CF(CF3)CF2O] a -(CF2) b - and at least one of their combinations.

[0331] In the formula, a, b, c and d are independently at least 1. a, b, c and d can independently be 2 or more, 3 or more, 4 or more, 10 or more, or 20 or more. The upper limit of a, b, c and d is, for example, 100.

[0332] As R, the general formula (r1) is preferred:

[0333] -CF2-O-(CX 6 2) e -{O-CF(CF3)} f -(O) g -(r1)

[0334] (Where X 6 Each is independently H, F or CF3, e is an integer of 0 to 3, f is an integer of 0 to 3, g is 0 or 1), and more preferably the general formula (r2):

[0335] -CF2-O-(CX 7 2) e -(O) g -(r2)

[0336] (Where X 7 Each independently represents H, F or CF3, e represents an integer of 0 to 3, and g represents a divalent group represented by 0 or 1).

[0337] Preferred specific examples of R include -CF2-O-, -CF2-O-CF2-, -CF2-O-CH2-, -CF2-O-CH2CF2-, -CF2-O-CF2CF2-, -CF2-O-CF2CH2-, -CF2-O-CF2CF2CH2-, -CF2-O-CF(CF3)-, -CF2-O-CF(CF3)CF2-, -CF2-O-CF(CF3)CF2-, -CF2-O-CF(CF3)CF2-O-, -CF2-O-CF(CF3)CF2-O-CF2-, -CF2-O-CF(CF3)CH2-, etc. Among them, R is preferably a perfluoroalkylene group containing or not containing an oxygen atom, specifically, -CF2-O-, -CF2-O-CF2-, -CF2-O-CF2CF2-, -CF2-O-CF(CF3)-, -CF2-O-CF(CF3)CF2-, or -CF2-O-CF(CF3)CF2-O-.

[0338] As -R-CZ of general formula (I) 1 Z 2 -, preferably general formula (s1):

[0339] -CF2-O-(CX 6 2) e -{O-CF(CF3)} f -(O) g -CZ 1 Z 2 -(s1)

[0340] (Where X 6 Each independently represents H, F or CF3, e represents an integer of 0 to 3, f represents an integer of 0 to 3, g represents 0 or 1, Z 1 and Z 2 Each independently represents H, F, alkyl or fluorinated alkyl), wherein Z 1 and Z 2 More preferably, it is F or CF3, and even more preferably, one is F and the other is CF3.

[0341] In the general formula (I), -R-CZ 1 Z 2 -, preferably general formula (s2):

[0342] -CF2-O-(CX 7 2) e -(O) g -CZ 1 Z 2 -(s2)

[0343] (Where X 7Each independently represents H, F or CF3, e represents an integer from 0 to 3, g represents 0 or 1, Z 1 and Z 2 Each independently represents H, F, alkyl or fluorinated alkyl), wherein Z 1 and Z 2 More preferably, it is F or CF3, and even more preferably, one is F and the other is CF3.

[0344] As -R-CZ of general formula (I) 1 Z 2 -, preferably -CF2-O-CF2-, -CF2-O-CF(CF3)-, -CF2-OC(CF3)2-, -CF2-O-CF2-CF2-, -CF2-O-CF2-CF (CF3)-, -CF2-O-CF2-C(CF3)2-, -CF2-O-CF2CF2-CF2-, -CF2-O-CF2CF2-CF(CF3)-, -CF2-O- CF2CF2-C(CF3)2-, -CF2-O-CF(CF3)-CF2-, -CF2-O-CF(CF3)-CF(CF3)-, -CF2-O-CF(CF3)-C (CF3)2-, -CF2-O-CF(CF3)-CF2-, -CF2-O-CF(CF3)-CF(CF3)-, -CF2-O-CF(CF3)-C(CF3)2-, -CF2-O-CF(CF3)CF2-CF2-, -CF2-O-CF(CF3)CF2-CF(CF3)-, -CF2-O-CF(CF3)CF2-C(CF3)2- , -CF2-O-CF(CF3)CF2-O-CF2-, -CF2-O-CF(CF3)CF2-O-CF(CF3)-, or -CF2-O-CF(CF3)CF2-O C(CF3)2-, more preferably -CF2-O-CF(CF3)-, -CF2-O-CF2-CF(CF3)-, -CF2-O-CF2CF2-CF(CF3)-, -CF2- O-CF(CF3)-CF(CF3)-, -CF2-O-CF(CF3)CF2-CF(CF3)-, or -CF2-O-CF(CF3)CF2-O-CF(CF3)-.

[0345] The polymer α is also preferably highly fluorinated. For example, it is preferred that anionic groups (A) such as phosphate moieties (e.g., CH2OP(O)(OM)2) and sulfate moieties (e.g., CH2OS(O)2OM) are not included. 0), more than 80%, more than 90%, more than 95%, or 100% of the CH bonds in the polymer α are replaced by CF bonds. The proportion of hydrogen atoms bonded to carbon atoms in the polymer α being replaced by fluorine atoms is 50% or more, and is not particularly limited, but is preferably 80% or more, more preferably 90% or more, further preferably 95% or more, and particularly preferably 100%.

[0346] The polymer α also preferably has an anionic group (A 0 ) has a CF bond and does not have a CH bond. That is, in the general formula (I), preferably X 1 , X 2 and X 3 All of them are F, R is a perfluoroalkylene group having 1 or more carbon atoms, the perfluoroalkylene group may be any of a chain or branched chain, may be any of a cyclic or acyclic chain, and may contain at least one chain heteroatom. The perfluoroalkylene group may have 2 to 20 carbon atoms, or 4 to 18 carbon atoms.

[0347] The polymer α may also be partially fluorinated. That is, the polymer α is also preferably fluorinated except for the anionic group (A 0 ) has at least one hydrogen atom bonded to a carbon atom and at least one fluorine atom bonded to a carbon atom.

[0348] Anionic group (A 0 ) may be -SO3M, -OSO3M, -COOM, -SO2NR'CH2COOM, -CH2OP(O)(OM)2, [-CH2O]2P(O)(OM), -CH2CH2OP(O)(OM)2, [-CH2CH2O]2P(O)(OM), -CH2CH2OSO3M, -P(O)(OM)2, -SO2NR'CH2CH2OP(O)(OM)2, [-SO2NR'CH2CH2O]2P(O)(OM), -CH2OSO3M, -SO2NR'CH2CH2OSO3M, or -C(CF3)2OM. Among them, -SO3M, -COOM or -P(O)(OM)2 is preferred, -SO3M or -COOM is more preferred, and -COOM is further preferred.

[0349] M is H, metal atom, NR 7 4. an imidazolium which may be substituted, a pyridinium which may be substituted, or a phosphonium which may be substituted, R 7 is H or an organic group.

[0350] Examples of the metal atom include alkali metals (Group 1) and alkaline earth metals (Group 2), and Na, K or Li is preferred.

[0351] As M, -H, a metal atom or NR 7 4, more preferably -H, alkali metal (Group 1), alkaline earth metal (Group 2) or NR 7 4, further preferably -H, -Na, -K, -Li or NH4, still more preferably -Na, -K or NH4, particularly preferably -Na or NH4, and most preferably -NH4.

[0352] In the polymer α, each structural unit (I) may have a different anionic group or may have the same anionic group.

[0353] The polymer α is also preferably a polymer including a structural unit (Ia) based on a monomer represented by the general formula (Ia).

[0354] CF2=CF-O-Rf 0 -A 0 (Ia)

[0355] (In the formula, A 0 is an anionic group, Rf 0 It is perfluorinated and may be chain or branched, cyclic or acyclic, saturated or unsaturated, substituted or unsubstituted, and is a perfluorinated divalent linking group that optionally contains one or more heteroatoms selected from the group consisting of sulfur, oxygen and nitrogen.

[0356] The polymer α is also preferably a polymer including a structural unit (Ib) based on a monomer represented by the general formula (Ib).

[0357] CH2=CH-O-Rf 0 -A 0 (Ib)

[0358] (In the formula, A 0 is an anionic group, Rf 0 is a perfluorinated divalent linking group as defined in Formula Ia.

[0359] The polymer α is also preferably a polymer including a structural unit (Ic) based on a monomer represented by the general formula (Ic).

[0360] CH2=CF-O-Rf 0 -A 0 (Ic)

[0361] (In the formula, A 0 is an anionic group, Rf 0 is a perfluorinated divalent linking group as defined in Formula Ia.

[0362] In the general formula (I), A 0 A sulfate ester group is one of the preferred forms. 0For example, it is -CH2OSO3M, -CH2CH2OSO3M, or -SO2NR'CH2CH2OSO3M, wherein R' is H or an alkyl group having 1 to 4 carbon atoms, and M is the same as above.

[0363] A 0 In the case of a sulfate group, examples of the monomer represented by the general formula (I) include CF2=CF(OCF2CF2CH2OSO3M), CH2=CH((CF2)4CH2OSO3M), CF2=CF(O(CF2)4CH2OSO3M), CF2=CF(OCF2CF(CF3)CH2OSO3M), CF2=CF(OCF2CF(CF3)OCF2CF2CH2OSO3M), CH2=CH((CF2)4CH2OSO3M), CF2=CF(OCF2CF2SO2N(CH3)CH2CH2OSO3M), CH2=CH(CF2CF2CH2OSO3M), CF2=CF(OCF2CF2CF2CF2SO2N(CH3)CH2CH2OSO3M), CH2=CH(CF2CF2CH2OSO3M), CF2=CF(OCF2CF2CF2CF2SO2N(CH3)CH2CH2OSO3M), CH2=CH(CF2CF2CF2CH2OSO3M). In the above formula, M is the same as above.

[0364] In the general formula (I), A 0 A sulfonate group is also one of the preferred embodiments. 0 , for example -SO3M, where M is the same as above.

[0365] A 0 In the case of a sulfonate group, examples of the monomer represented by the general formula (I) include CF2=CF(OCF2CF2SO3M), CF2=CF(O(CF2)3SO3M), CF2=CF(O(CF2)4SO3M), CF2=CF(OCF2CF(CF3)SO3M), CF2=CF(OCF2CF(CF3)OCF2CF2SO3M), CH2=CH(CF2CF2SO3M), CF2=CF(OCF2CF(CF3)OCF2CF2CF2SO3M), CH2=CH((CF2)4SO3M), CH2=CH(CF2CF2SO3M), and CH2=CH((CF2)3SO3M). In the above formula, M is the same as above.

[0366] In the general formula (I), A 0 A carboxylic acid ester group is also one of the preferred embodiments. 0 , for example, COOM or SO2NR'CH2COOM, wherein R' is H or an alkyl group having 1 to 4 carbon atoms, and M is the same as above. 0In the case of a carboxylate group, examples of the monomer represented by the general formula (I) include CF2=CF(OCF2CF2COOM), CF2=CF(O(CF2)3COOM), CF2=CF(O(CF2)5COOM), CF2=CF(OCF2CF(CF3)COOM), CF2=CF(OCF2CF(CF3)O(CF2) n COOM) (n is greater than 1), CH2=CH(CF2CF2COOM), CH2=CH((CF2)4COOM), CH2=CH(CF2CF2COOM), CH2=CH((CF2)3COOM), C F2=CF(OCF2CF2SO2NR'CH2COOM), CF2=CF(O(CF2)4SO2NR'CH2COOM), CF2=CF(OCF2CF(CF3)SO2NR'CH2COOM) , CF2=CF(OCF2CF(CF3)OCF2CF2SO2NR'CH2COOM) , CH2=CH(CF2CF2SO2NR'CH2COOM) , CF2=CF(OCF2CF(CF3)OCF2CF2CF2CF2SO2NR'CH2COOM) , CH2=CH((CF2)4SO2NR'CH2COOM), CH2=CH(CF2CF2SO2NR'CH2COOM), CH2=CH((CF2)3SO2NR'CH2COOM), etc. In the above formula, R' is H or an alkyl group having 1 to 4 carbon atoms, and M is the same as above.

[0367] In the general formula (I), A 0 A phosphate group is also one of the preferred embodiments. 0 , for example, -CH2OP(O)(OM)2, [-CH2O]2P(O)(OM), -CH2CH2OP(O)(OM)2, [-CH2CH2O]2P(O)(OM), [-SO2NR'CH2CH2O]2P(O)(OM) or SO2NR'CH2CH2OP(O)(OM)2, wherein R' is an alkyl group having 1 to 4 carbon atoms, and M is the same as above.

[0368] A 0In the case of a phosphate ester, examples of the monomer represented by the general formula (I) include CF2=CF(OCF2CF2CH2OP(O)(OM)2), CF2=CF(O(CF2)4CH2OP(O)(OM)2), CF2=CF(OCF2CF(CF3)CH2OP(O)(OM)2), CF2=CF(OCF2CF(CF3)OCF2CF2CH2OP(O)(OM)2), CF2=CF(OCF2CF2SO2N(CH3)CH2CH2OP(O)(OM)2), CF2=CF(OCF2CF2CF2CF2SO2N(CH3)CH2CH2OP(O)(OM)2), CH2=CH(CF2CF2CH2OP(O)(OM)2), CH2=CH((CF2)4CH2OP(O)(OM)2), CH2=CH(CF2CF2CH2OP(O)(OM)2), CH2=CH((CF2)3CH2OP(O)(OM)2), etc. In the above formula, M is the same as above.

[0369] In the general formula (I), A 0 It is also a preferred embodiment that the phosphonate group is a phosphonate group. 0 In the case of a phosphonate group, examples of the monomer represented by the general formula (I) include CF2=CF(OCF2CF2P(O)(OM)2), CF2=CF(O(CF2)4P(O)(OM)2), CF2=CF(OCF2CF(CF3)P(O)(OM)2), CF2=CF(OCF2CF(CF3)OCF2CF2P(O)(OM)2), CH2=CH(CF2CF2P(O)(OM)2), CH2=CH((CF2)4P(O)(OM)2), CH2=CH(CF2CF2P(O)(OM)2), and CH2=CH((CF2)3P(O)(OM)2), wherein M is the same as above.

[0370] Examples of the polymer α include, for example, a polymer having the following general formula (1):

[0371] CX2=CY(-CZ2-O-Rf-A) (1)

[0372] (wherein, X is the same or different and is -H or -F, Y is -H, -F, alkyl or fluorinated alkyl, and Z is the same or different and is -H, -F, alkyl or fluorinated alkyl. Rf is a fluorinated alkylene group having 1 to 40 carbon atoms, or a fluorinated alkylene group having 2 to 100 carbon atoms and having an ether bond. A is -COOM, -SO3M, -OSO3M or -C(CF3)2OM (M is -H, a metal atom, -NR 74. an imidazolium which may be substituted, a pyridinium which may be substituted, or a phosphonium which may be substituted, R 7 is H or an organic group). wherein at least one of X, Y and Z contains a fluorine atom. ) is a polymer of the structural unit M3 of the monomer represented by.

[0373] The structural unit M3 contained in the polymer α is the same as the structural unit M3 contained in the above-mentioned fluorine-containing polymer, and the preferred structure is also the same.

[0374] The polymer α is also preferably a polymer containing the structural unit (2) based on the monomer represented by the general formula (2).

[0375] CX2=CY(-O-Rf-A) (2)

[0376] (In the formula, X is the same or different and is -H or F, Y is -H, -F, alkyl or fluorinated alkyl, Rf is a fluorinated alkylene group having 1 to 40 carbon atoms or a fluorinated alkylene group having an ether bond having 2 to 100 carbon atoms. A is the same as above.)

[0377] In the general formula (2), X is -H or F. Both Xs may be -F, or at least one of them may be -H. For example, one may be -F and the other may be -H, or both may be -H.

[0378] In the general formula (2), Y is -H, -F, an alkyl group or a fluorine-containing alkyl group. The alkyl group is an alkyl group not containing fluorine atoms, and the number of carbon atoms may be 1 or more. The number of carbon atoms of the above-mentioned alkyl group is preferably 6 or less, more preferably 4 or less, and further preferably 3 or less. The fluorine-containing alkyl group is an alkyl group containing at least 1 fluorine atom, and the number of carbon atoms may be 1 or more. The number of carbon atoms of the above-mentioned fluorine-containing alkyl group is preferably 6 or less, more preferably 4 or less, and further preferably 3 or less. As Y, -H, -F or -CF3 is preferred, and -F is more preferred.

[0379] In the general formula (2), at least one of X and Y preferably contains a fluorine atom. For example, X may be -H, and Y and Z may be -F.

[0380] In the general formula (2), Rf is a fluorinated alkylene group having 1 to 40 carbon atoms or a fluorinated alkylene group having an ether bond having 2 to 100 carbon atoms. The fluorinated alkylene group having an ether bond having 2 to 100 carbon atoms is an alkylene group having an ether bond between carbon atoms and not having an oxygen atom at the end.

[0381] The number of carbon atoms of the fluorinated alkylene group of Rf is preferably 2 or more. In addition, it is preferably 30 or less, more preferably 20 or less, and further preferably 10 or less. Examples of the fluorinated alkylene group include -CF2-, -CH2CF2-, -CF2CF2-, -CF2CH2-, -CF2CF2CH2-, -CF(CF3)-, -CF(CF3)CF2-, -CF(CF3)CH2-, etc. The fluorinated alkylene group is preferably a perfluoroalkylene group.

[0382] The monomer represented by the general formula (2) is preferably at least one selected from the group consisting of monomers represented by the general formulae (2a), (2b), (2c), (2d) and (2e).

[0383] CF2=CF-O-(CF2) n1 -A(2a)

[0384] (In the formula, n1 represents an integer of 1 to 10, and A is the same as above.)

[0385] CF2=CF-O-(CF2C(CF3)F) n2 -A(2b)

[0386] (In the formula, n2 represents an integer of 1 to 5, and A has the same definition as above.)

[0387] CF2=CF-O-(CFX 1 ) n3 -A(2c)

[0388] (Where X 1 represents F or CF3, n3 represents an integer from 1 to 10, and A has the same definition as above. )

[0389] CF2=CF-O-(CF2CFX 1 O) n4 -(CF2) n6 -A(2d)

[0390] (wherein, n4 represents an integer of 1 to 10, n6 represents an integer of 1 to 3, A and X 1 Same as the above definition.)

[0391] CF2=CF-O-(CF2CF2CFX 1 O) n5 -CF2CF2CF2-A(2e)

[0392] (where n5 represents an integer from 1 to 10, A and X 1 Same as the above definition.)

[0393] In the general formula (2a), the above n1 is preferably an integer of 5 or less, more preferably an integer of 2 or less.

[0394] Examples of the monomer represented by the general formula (2a) include CF2=CF-O-CF2COOM, CF2=CF(OCF2CF2COOM) and CF2=CF(OCF2CF2CF2COOM) (wherein M has the same meaning as defined above).

[0395] In the general formula (2b), n2 is preferably an integer of 3 or less from the viewpoint of water solubility.

[0396] In the general formula (2c), from the viewpoint of water solubility, n3 is preferably an integer of 5 or less, the above-mentioned A is preferably -COOM, and the above-mentioned M is preferably H or NH4.

[0397] In the general formula (2d), from the viewpoint of water solubility, X 1 It is preferably -CF3, and from the viewpoint of water solubility, n4 is preferably an integer of 5 or less, A is preferably -COOM, and M is preferably H or NH4.

[0398] Examples of the monomer represented by the general formula (2d) include CF2=CFOCF2CF(CF3)OCF2CF2COOM, CF2=CFOCF2CF(CF3)OCF2COOM, and CF2=CFOCF2CF(CF3)OCF2CF2CF2COOM (wherein M represents H, NH4 or an alkali metal).

[0399] In the general formula (2e), from the viewpoint of water solubility, n5 is preferably an integer of 5 or less, A is preferably -COOM, and M is preferably H or NH4.

[0400] Examples of the monomer represented by the general formula (2e) include CF2=CFOCF2CF2CF2COOM (wherein M represents H, NH4 or an alkali metal).

[0401] The polymer α is also preferably a polymer containing a structural unit (3) based on a monomer represented by the general formula (3).

[0402] CX2=CY(-Rf-A) (3)

[0403] (In the formula, X is the same or different and is -H or -F, Y is -H, -F, an alkyl group or a fluorinated alkyl group, Rf is a fluorinated alkylene group having 1 to 40 carbon atoms, or a fluorinated alkylene group having an ether bond having 2 to 100 carbon atoms. A is the same as above.)

[0404] The fluorine-containing alkylene group having an ether bond and having 2 to 100 carbon atoms is an alkylene group having no structure with an oxygen atom at the end and having an ether bond between carbon atoms.

[0405] In the general formula (3), Rf is preferably a fluorine-containing alkylene group having 1 to 40 carbon atoms. In the general formula (3), at least one of X and Y preferably contains a fluorine atom.

[0406] The monomer represented by the general formula (3) is preferably selected from the general formula (3a):

[0407] CF2=CF-(CF2) n1 -A(3a)

[0408] (wherein n1 represents an integer of 1 to 10, and A has the same meaning as defined above) and the general formula (3b):

[0409] CF2=CF-(CF2C(CF3)F) n2 -A(3b)

[0410] (wherein n2 represents an integer of 1 to 5, and A has the same meaning as defined above) is at least one member selected from the group consisting of monomers represented by

[0411] In the general formula (3a) and the general formula (3b), A is preferably -SO3M or COOM, and M is preferably H, a metal atom, NR 7 4. An imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent. 7 represents H or an organic group.

[0412] In the general formula (3a), n1 is preferably an integer of 5 or less, and more preferably an integer of 2 or less. A is preferably -COOM, and M is preferably H or NH4.

[0413] Examples of the monomer represented by the general formula (3a) include CF2=CFCF2COOM (wherein M has the same meaning as defined above).

[0414] In the general formula (3b), from the viewpoint of water solubility, n2 is preferably an integer of 3 or less, A is preferably -COOM, and M is preferably H or NH4.

[0415] The polymer α is preferably at least one selected from the group consisting of a polymer containing the structural unit M3, a polymer containing the structural unit (2), and a polymer containing the structural unit (3), and more preferably a polymer containing the structural unit M3.

[0416] In addition, examples of the polymer α include polymers α containing a structural unit (II) based on a monomer represented by the general formula (II). The polymer α preferably contains two or more structural units (II).

[0417] CX 1 X 3 =CX 2 R II (-CZ 1 Z 2 -A 0 ) nII (II)

[0418] (Where X 1 , X 2 , X 3 , A 0 , Z 1 and Z 2 Same as the above definition, R II is a (nII+1)-valent linking group, where nII is an integer greater than 2.)

[0419] nII is an integer greater than or equal to 2, and preferably 2. 1 , Z 2 and A 0 Can be the same or different.

[0420] Examples of the monomer represented by the general formula (II) include the monomer represented by the general formula (1-II), the monomer represented by the general formula (2-II), and the like.

[0421] CF2=CF-CF2-OQ F1 -CF(-Q F2 -CZ 1 Z 2 -A)2(1-II)

[0422] (Where Z 1 , Z 2 and A are the same as above, Q F1 and Q F2 The same or different, a single bond, a fluorinated alkylene group containing or not containing an ether bond between carbons, or a fluorinated oxyalkylene group containing or not containing an ether bond between carbons.

[0423] CF2=CF-OQ F1 -CF(-Q F2 -CZ 1 Z 2 -A)2(2-II)

[0424] (Where Z 1 , Z 2 , A, Q F1 and QF2 Same as the above definition.)

[0425] Examples of the monomer represented by the general formula (II) include

[0426] [Chemistry 16]

[0427] wait.

[0428] The above-mentioned polymer α may contain structural units based on fluorine-containing monomers such as trifluoroethylene, tetrafluoroethylene (TFE), vinylidene fluoride (VdF), vinyl fluoride (VF), chlorotrifluoroethylene (CTFE), hexafluoropropylene (HFP), hexafluoroisobutylene, perfluoroalkylethylene, fluorovinyl ether (FVE), CH2=CFCF3, CHF=CHCF3 (E body), CHF=CHCF3 (Z body), etc. (excluding monomers represented by general formula (I) and general formula (II)).

[0429] The polymer α may also contain structural units based on non-fluorine-containing monomers. As non-fluorine-containing monomers, any monomer having a free radical polymerizable ethylenic unsaturated bond may be used, and examples thereof include acrylates, methacrylates, unsaturated carboxylic acids, monomers containing hydrolyzable silyl groups, hydroxyl-containing alkyl vinyl ethers, carboxylic acid vinyl esters, α-olefins, etc. As the non-fluorine-containing monomer, at least one selected from the group consisting of acrylates, methacrylates, unsaturated carboxylic acids, and monomers containing hydrolyzable silyl groups is preferred.

[0430] The non-fluorine-containing monomer is more preferably at least one selected from the group consisting of at least one monomer selected from the group consisting of acrylic acid esters and methacrylic acid esters, unsaturated carboxylic acids, and hydrolyzable silyl group-containing monomers.

[0431] In addition to these, a monomer having a radical polymerizable ethylenically unsaturated bond may be used in combination.

[0432] As the above-mentioned acrylic acid ester or methacrylic acid ester, an alkyl acrylic acid ester having an alkyl group with 1 to 10 carbon atoms or an alkyl methacrylic acid ester having an alkyl group with 1 to 10 carbon atoms is preferred. Examples of the alkyl acrylic acid ester and the alkyl methacrylic acid ester include alkyl (meth)acrylic acid esters such as methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, methyl methacrylate, n-propyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, cyclohexyl acrylate, and cyclohexyl methacrylate. In addition, the above-mentioned alkyl acrylic acid ester or alkyl methacrylate ester may be a hydroxyl-containing acrylic acid monomer having a hydroxyl group and a (meth)acryloyl group in the molecule such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, and 4-hydroxybutyl methacrylate.

[0433] These acrylates or methacrylates may be used alone or in combination of two or more. Among them, n-butyl acrylate and methyl methacrylate are preferred.

[0434] The non-fluorine-containing monomer is preferably at least one alkyl (meth)acrylate selected from the group consisting of methyl methacrylate, n-butyl acrylate, 2-ethylhexyl methacrylate and cyclohexyl methacrylate. It should be noted that the acrylate or methacrylate does not contain a hydrolyzable silyl group.

[0435] As the acrylic acid ester or methacrylic acid ester, a combination of n-butyl acrylate and methyl methacrylate or a combination of n-butyl acrylate, methyl methacrylate and 2-ethylhexyl methacrylate is further preferred, and a combination of n-butyl acrylate, methyl methacrylate and 2-ethylhexyl methacrylate is particularly preferred. In addition, a combination of a hydroxyl-containing acrylic monomer having a hydroxyl group and a (meth)acryloyl group is also preferred.

[0436] Specific examples of the unsaturated carboxylic acids include acrylic acid, methacrylic acid, vinylacetic acid, crotonic acid, cinnamic acid, 3-allyloxypropionic acid, 3-(2-allyloxyethoxycarbonyl)propionic acid, itaconic acid, itaconic acid monoester, maleic acid, maleic acid monoester, maleic anhydride, fumaric acid, fumaric acid monoester, vinyl phthalate, vinyl pyromellitate, undecylenic acid, etc. Among them, from the perspective of low homopolymerization and difficulty in forming a homopolymer, and from the perspective of easy control of the introduction of a carboxyl group, it is preferably selected from at least one of the group consisting of acrylic acid, methacrylic acid, vinylacetic acid, crotonic acid, itaconic acid, maleic acid, maleic acid monoester, fumaric acid, fumaric acid monoester, 3-allyloxypropionic acid and undecylenic acid.

[0437] Examples of the hydrolyzable silyl group-containing monomer include:

[0438] CH2=CHCOO(CH2)3Si(OCH3)3,

[0439] CH2=CHCOO(CH2)3Si(CH3)(OCH3)2,

[0440] CH2=CHCOO(CH2)3Si(OC2H5)3,

[0441] CH2=CHCOO(CH2)3Si(CH3)(OC2H5)2,

[0442] CH2=C(CH3)COO(CH2)3Si(OCH3)3,

[0443] CH2=C(CH3)COO(CH2)3Si(CH3)(OCH3)2,

[0444] CH2=C(CH3)COO(CH2)3Si(OC2H5)3,

[0445] CH2=C(CH3)COO(CH2)3Si(CH3)(OC2H5)2,

[0446] CH2=C(CH3)COO(CH2)2O(CH2)3Si(OCH3)3,

[0447] CH2=C(CH3)COO(CH2)2(CH2)3Si(CH3)(OCH3)2,

[0448] CH2=C(CH3)COO(CH2) 11 Si(OCH3)3,

[0449] CH2=C(CH3)COO(CH2) 11 Si(CH3)(OCH3)2, etc. These hydrolyzable silyl group-containing monomers may be used alone or in combination of two or more.

[0450] As the hydrolyzable silyl group-containing monomer, at least one selected from the group consisting of γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltriethoxysilane and γ-methacryloxypropylmethyldiethoxysilane is preferred, and γ-methacryloxypropyltriethoxysilane is more preferred.

[0451] Examples of the hydroxyl-containing alkyl vinyl ethers include 2-hydroxyethyl vinyl ether, 3-hydroxypropyl vinyl ether, 2-hydroxypropyl vinyl ether, 2-hydroxy-2-methylpropyl vinyl ether, 4-hydroxybutyl vinyl ether, 4-hydroxy-2-methylbutyl vinyl ether, 5-hydroxypentyl vinyl ether, 6-hydroxyhexyl vinyl ether, 2-hydroxyethyl allyl ether, 4-hydroxybutyl allyl ether, and glycerol monoallyl ether. From the perspective of excellent polymerization reactivity, at least one selected from the group consisting of 4-hydroxybutyl vinyl ether and 2-hydroxyethyl vinyl ether is preferred.

[0452] Examples of the vinyl carboxylates include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caproate, vinyl versatate, vinyl laurate, vinyl stearate, vinyl cyclohexylcarboxylate, vinyl benzoate, and vinyl p-tert-butylbenzoate.

[0453] Examples of the α-olefins include ethylene, propylene, n-butene, isobutylene, and styrene.

[0454] In the above-mentioned polymer α, the content of structural unit (I) is preferably 50 mass% or more, more preferably 60 mass% or more, further preferably 70 mass% or more, even more preferably 80 mass% or more, especially preferably 90 mass% or more, particularly preferably 95 mass% or more, and most preferably 99 mass% or more.

[0455] In the above-mentioned polymer α, the content of the above-mentioned structural unit M3 is preferably 50 mass% or more, more preferably 60 mass% or more, further preferably 70 mass% or more, even more preferably 80 mass% or more, especially preferably 90 mass% or more, particularly preferably 95 mass% or more, and most preferably 99 mass% or more.

[0456] In the above-mentioned polymer α, the total content of structural units based on fluorine-containing monomers and structural units based on non-fluorine-containing monomers is preferably 50 mass% or less, more preferably 40 mass% or less, further preferably 30 mass% or less, even more preferably 20 mass% or less, especially preferably 10 mass% or less, particularly preferably 5 mass% or less, and most preferably 1 mass% or less.

[0457] The number average molecular weight of the polymer α is preferably 0.1×10 4 More preferably, 0.2×10 4 More preferably, 0.3×10 4 More preferably, 0.4×10 4 More than 0.5×10 4 More than 1.0×10 4Above, particularly preferably 3.0×10 4 More than, most preferably 3.1×10 4 In addition, it is preferably 75.0×10 4 Less than, more preferably 50.0×10 4 Below, more preferably 40.0×10 4 Below, especially preferably 30.0×10 4 Below, particularly preferably 20.0×10 4 the following.

[0458] If the number average molecular weight is too low, the dispersibility is reduced and it may not be used as a dispersant. If the number average molecular weight is too high, the viscosity is increased and the handling may become complicated.

[0459] The weight average molecular weight of the polymer α is preferably 0.2×10 4 More preferably, 0.4×10 4 More preferably, 0.6×10 4 More preferably, 0.8×10 4 More than 1.0×10 4 More preferably, 5.0×10 4 More preferably, 10.0×10 4 More than 15.0×10 4 Above, particularly preferably 20.0×10 4 More than, most preferably 25.0×10 4 In addition, it is preferably 150.0×10 4 Less than, more preferably 100.0×10 4 Below, more preferably 60.0×10 4 Below, particularly preferably 50.0×10 4 Below, especially preferably 40.0×10 4 the following.

[0460] The above-mentioned number average molecular weight and weight average molecular weight are the values ​​calculated as standard for molecular weight using monodisperse polyethylene oxide (PEO) and polyethylene glycol (PEG) manufactured by Tosoh Corporation and Agilent Corporation by gel permeation chromatography (GPC). In addition, when it is impossible to measure by GPC, the number average molecular weight of polymer α can be obtained based on the correlation between the number average molecular weight calculated by the number of terminal groups obtained by utilizing NMR, FT-IR, etc. and the melt flow rate. The melt flow rate can be measured according to JIS K 7210.

[0461] The polymer α is preferably a water-soluble polymer.

[0462] The polymer α has an ion exchange rate (IXR) of 53 or less. The IXR is preferably 0.5 or more, more preferably 1 or more, further preferably 3 or more, further more preferably 4 or more, particularly preferably 5 or more, and particularly preferably 8 or more. In addition, the IXR is preferably 43 or less, more preferably 33 or less, and further preferably 23 or less. In the polymer α, the ionic groups (anionic groups) are typically distributed along the polymer main chain. The polymer α preferably comprises a polymer main chain and a repeating side chain bonded to the main chain, and the side chain has an ionic group.

[0463] The polymer α preferably comprises an ionic group (anionic group) having a pKa of less than 10, more preferably less than 7. The ionic group of the polymer α is preferably selected from the group consisting of sulfonates, carboxylates, phosphonates, phosphates and mixtures thereof.

[0464] The terms "sulfonate, carboxylate, phosphonate and phosphate" refer to the respective salts or the respective acids capable of forming salts. In the case of using a salt, it is preferably an alkali metal salt or an ammonium salt. The preferred ionic group is a sulfonate group.

[0465] In the composition containing the polymer α, the concentration of the polymer α is not particularly limited, and may be, for example, 0.1% by mass to 20% by mass.

[0466] Since the removal efficiency of low molecular weight bodies is more efficient, the concentration of the above polymer α is preferably 18.0 mass % or less. More preferably, it is 15.0 mass % or less, further preferably 12.0 mass % or less, and particularly preferably 10.0 mass % or less. By making the concentration of the above polymer α within the above range, low molecular weight bodies can be removed more efficiently. The concentration of the above polymer α is preferably 0.5 mass % or more, more preferably 1.0 mass % or more, further preferably 1.2 mass % or more, and particularly preferably 1.5 mass % or more.

[0467] The composition containing the polymer α may contain a single polymer α or may contain two or more different polymers α.

[0468] The pH of the composition containing the polymer α is preferably 0 to 11, more preferably 0.5 to 8.0. The pH can be adjusted using a pH adjuster. The pH adjuster may be an acid or a base, such as phosphate, sodium hydroxide, potassium hydroxide, ammonia water, and the like.

[0469] The second production method of the present invention also preferably includes a step of adjusting the pH of the composition containing the polymer α to 1.0 to 7.0 before step A1.

[0470] The composition containing the above-mentioned polymer α can be obtained by a known polymerization method for obtaining the above-mentioned polymer α. The second manufacturing method of the present invention includes a step of polymerizing monomers to obtain polymer α, which is also one of the preferred embodiments. The above-mentioned monomers can be appropriately selected from the monomers constituting the above-mentioned polymer α. The step of obtaining the above-mentioned polymer α is preferably carried out in an aqueous medium. That is, the second manufacturing method of the present invention also preferably includes the following step: polymerizing the monomers represented by general formula (I) in an aqueous medium, thereby obtaining a composition containing polymer α.

[0471] The composition containing the above-mentioned polymer α may be a polymerized composition obtained by polymerization, a diluted or concentrated polymerized composition obtained by polymerization, or a dispersion stabilization treatment. In order to smoothly perform ultrafiltration, microfiltration or dialysis membrane treatment, it is also preferred to adjust the viscosity of the composition containing polymer α by these treatments.

[0472] Since ultrafiltration, microfiltration or dialysis membrane treatment is smoothly performed, the viscosity of the composition containing polymer α used in step A1 is preferably 25 mPa·s or less. The viscosity of the composition can be adjusted, for example, by a method of adjusting the number average molecular weight of polymer α, a method of adjusting the concentration of polymer α in the composition, a method of adjusting the temperature of the composition, etc.

[0473] The above-mentioned polymerization usually generates low molecular weight products as by-products. In the second production method of the present invention, the low molecular weight products can be removed by subjecting the composition containing the polymer α to a treatment such as ultrafiltration.

[0474] The composition containing the polymer α used in step A1 may contain low molecular weight substances. For example, the content of the low molecular weight substances is preferably more than 5.0%, more preferably 5.5% or more, further preferably 6.0% or more, or more than 2.0% relative to the polymer α.

[0475] As low molecular weight bodies, for example, compounds having a molecular weight of 700 to 3000, compounds having a molecular weight of 400 to 3000, compounds having a molecular weight of 700 to less than 10000, dimers and trimers of monomers forming structural units M3, dimers and trimers of monomers forming structural units constituting polymer α described later, dimers and trimers of monomers forming structural units constituting water-soluble polymers described later, etc. can be cited.

[0476] The content of the low molecular weight body is a value calculated from the peak area of ​​GPC and / or a value calculated by measurement using liquid chromatography-mass spectrometry (LC / MS / MS).

[0477] Furthermore, by using the second production method of the present invention, dimers and trimers of monomers that form structural units constituting the polymer α can also be removed from the composition containing the polymer α.

[0478] As dimers and trimers, dimers and trimers of monomers represented by general formula (I) (hereinafter sometimes referred to as monomers (I)) may be used. Dimers and trimers may be polymers formed from one monomer (I) as monomer (I) represented by general formula (I), or may be copolymers formed from two or more monomers (I) having different structures. In addition, dimers and trimers of monomers described above as monomers forming preferred structural units constituting polymer α may be used.

[0479] As described above, the composition containing the polymer α can be produced by, for example, polymerizing the monomer (I).

[0480] In the composition obtained by polymerizing the monomer (I), the polymer as the monomer (I) generally contains dimers and trimers in an amount exceeding 1.0% by weight in total relative to the mass of the polymer of the monomer (I). The content of dimers and trimers in the polymer as the monomer (I) may be, for example, 2.0% or more, 3.0% or more, 30.0% or less, or 20.0% or less relative to the polymer of the monomer (I). The content of dimers and trimers in the composition can be determined by performing gel permeation chromatography (GPC) analysis of the composition and calculating the ratio (area percentage) of the total peak area of ​​dimers and trimers in the chromatogram obtained by the GPC analysis to the total area of ​​each peak.

[0481] It was previously unknown that dimers and trimers of monomer (I) are generated by polymerization of monomer (I), and as a result, dimers and trimers of monomer (I) are included in polymer α. The mechanism for generating dimers and trimers of monomer (I) may not be clear, but it is speculated that it is due to: in particular, due to the polymerization reaction in the polymerization system in which monomer (I) among the monomers present in the polymerization system accounts for the majority, dimers and trimers of monomer (I) are generated at a frequency that cannot be ignored. In the present invention, the existence of dimers and trimers of monomer (I) in polymer α is clarified for the first time, and it is discovered for the first time that dimers and trimers of monomer (I) in polymer α are efficiently removed from polymer α by at least one mechanism selected from the group consisting of ultrafiltration, microfiltration and dialysis membrane treatment.

[0482] When removing dimers and trimers, generally, unreacted monomer (I) is also removed from the composition.

[0483] By removing dimers and trimers from a composition containing dimers and trimers, a composition substantially free of dimers and trimers can be obtained.

[0484] The content of dimers and trimers in the composition obtained by the second production method of the present invention is preferably 1.0% or less, more preferably 0.1% or less, further preferably 0.01% or less, particularly preferably 0.001% or less, and most preferably 0.0001% or less, based on polymer α.

[0485] The content of dimers and trimers in the composition can be determined by performing gel permeation chromatography (GPC) analysis on the composition and calculating the ratio (area percentage) of the total peak area of ​​dimers and trimers in the chromatogram obtained by GPC analysis to the total area of ​​each peak.

[0486] When the content of the dimer and trimer in the composition is less than 0.5% based on the polymer α, it can be identified by measurement using liquid chromatography-mass spectrometry (LC / MS / MS).

[0487] Specifically, compositions having five or more levels of the content of the monomer (I) were prepared, LC / MS / MS analysis was performed for each content, and the relationship between the content and the area (integral value of the peak) relative to the content was plotted to prepare a calibration curve for the monomer (I). Furthermore, calibration curves for dimers and trimers of the monomer (I) were prepared from the calibration curve for the monomer (I).

[0488] Methanol was added to the polymer α to prepare a mixture, and an extract (supernatant) was recovered from the mixture by centrifugal separation. The obtained extract was analyzed by LC / MS / MS.

[0489] Then, the area of ​​the dimer and trimer chromatogram of the monomer (I) (integrated value of the peak) can be converted into the content of the dimer and trimer using the calibration curve.

[0490] The present invention also relates to a method for manufacturing a composition (hereinafter also referred to as "the third manufacturing method of the present invention"), characterized in that it includes the following step A2: subjecting a composition comprising water and a water-soluble polymer in which hydrogen atoms bonded to carbon atoms are replaced by fluorine atoms in a ratio of 50% or more to ultrafiltration, microfiltration or dialysis membrane treatment, or a combination thereof.

[0491] The composition obtained by the third production method of the present invention may be an aqueous solution.

[0492] In the third production method of the present invention, the above step A2 can be entirely the same as the first production method of the present invention except that a composition containing water and a water-soluble polymer in which 50% or more of hydrogen atoms bonded to carbon atoms are replaced with fluorine atoms is used.

[0493] In the above step A2, the above ultrafiltration, microfiltration or dialysis membrane treatment is preferably performed at a temperature of 10°C or higher. It is more preferably 15°C or higher, further preferably 20°C or higher, and particularly preferably 30°C or higher. By setting the temperature within the above range, low molecular weight substances can be reduced more efficiently. The above temperature is preferably 90°C or lower, more preferably 80°C or lower, further preferably 70°C or lower, and particularly preferably 60°C or lower.

[0494] Ultrafiltration preferably uses a molecular weight cut-off of 1.5×10 4 Da or more ultrafiltration membrane.

[0495] The water-soluble polymer is not particularly limited. For example, a water-soluble polymer in which the hydrogen atoms bonded to carbon atoms in the fluorine-containing polymer are replaced by fluorine atoms at a ratio of 50% or more may be used, or a water-soluble polymer in which the hydrogen atoms bonded to carbon atoms in the polymer α are replaced by fluorine atoms at a ratio of 50% or more may be used.

[0496] The present invention also relates to a composition (hereinafter also referred to as "the first composition of the present invention"), characterized in that it contains water and a fluorine-containing polymer, wherein the fluorine-containing polymer is a polymer containing a structural unit M3 derived from a monomer represented by the general formula (1),

[0497] CX2=CY(-CZ2-O-Rf-A) (1)

[0498] (wherein, X is the same or different and is -H or -F, Y is -H, -F, alkyl or fluorinated alkyl, and Z is the same or different and is -H, -F, alkyl or fluorinated alkyl. Rf is a fluorinated alkylene group having 1 to 40 carbon atoms, or a fluorinated alkylene group having 2 to 100 carbon atoms and having an ether bond. A is -COOM, -SO3M, -OSO3M or -C(CF3)2OM (M is -H, a metal atom, -NR 7 4. an imidazolium which may be substituted, a pyridinium which may be substituted, or a phosphonium which may be substituted, R 7 is H or an organic group). wherein at least one of X, Y and Z contains a fluorine atom.

[0499] In the composition, the content of the compound having a molecular weight of 700 to 3000 is 3.5% or less based on the fluorinated polymer.

[0500] The first composition of the present invention may be an aqueous solution.

[0501] In the first composition of the present invention, the content of the compound having a molecular weight of 400 to 3000 is preferably 3.7% or less based on the fluorinated polymer.

[0502] In the first composition of the present invention, the content of the compound having a molecular weight of 700 or more and less than 10,000 is preferably 5.0% or less based on the fluorinated polymer.

[0503] The first composition of the present invention has a reduced amount of low molecular weight substances, and therefore, when used as a dispersant in a polymer dispersion, can improve dispersibility (property of dispersing other components).

[0504] In addition, the coating agent obtained from the first composition of the present invention is excellent in transparency, water resistance, and antireflection property.

[0505] The first composition of the present invention can be suitably produced by the first production method of the present invention.

[0506] The first composition of the present invention contains water. The content of water is not limited, but is preferably an amount in which the fluorine-containing polymer can be dispersed or dissolved.

[0507] Examples of the fluorinated polymer in the first composition of the present invention include the fluorinated polymers described in the first production method of the present invention. In addition, all preferred embodiments may be adopted.

[0508] For example, in the general formula (1), at least one of X may be -H, or both may be -H. The above Rf is preferably a fluorinated alkylene group having 1 to 10 carbon atoms, or a fluorinated alkylene group having 2 to 12 carbon atoms and having an ether bond. A is preferably -COOM, and M is preferably -H, -Na, -K, -Li or -NH4.

[0509] As the structural unit M3, for example, it is preferably based on the following general formula (1a):

[0510] CX2=CFCF2-O-(CF(CF3)CF2O) n5 -CF(CF3)-A(1a)

[0511] The structural unit (1a) of the fluoroallyl ether compound represented by (wherein each X is the same and represents F or H. n5 represents 0 or an integer from 1 to 10, and A has the same meaning as defined above) is also preferably a structural unit (1A) based on a monomer represented by the following general formula (1A).

[0512] CH2=CF(-CF2-O-Rf-A)(1A)

[0513] (Wherein, Rf and A are the same as above.)

[0514] In the fluorine-containing polymer, the ratio in which hydrogen atoms bonded to carbon atoms are replaced with fluorine atoms is preferably 50% or more.

[0515] The fluorinated polymer preferably contains an ionic group, and the ion exchange rate is preferably 53 or less.

[0516] In the fluorine-containing polymer, the ratio in which hydrogen atoms bonded to carbon atoms are replaced with fluorine atoms is preferably 50% or more.

[0517] The above-mentioned fluorine-containing polymer is preferably a water-soluble polymer.

[0518] In the first composition of the present invention, the content (concentration) of the fluorinated polymer is not particularly limited, and may be, for example, 0.1% by mass to 10.0% by mass based on the composition.

[0519] The first composition of the present invention may be a composition obtained by diluting or concentrating the composition obtained by the first production method of the present invention.

[0520] The first composition of the present invention may contain a single fluorinated polymer or may contain two or more different fluorinated polymers.

[0521] In the first composition of the present invention, the content of the compound having a molecular weight of 700 to 3000 is 3.5% or less relative to the fluorinated polymer. By making the content of the compound having a molecular weight of 700 to 3000 within the above range, the dispersibility is excellent. It is preferably 3.0% or less, more preferably 2.5% or less, further preferably 1.5% or less, particularly preferably 1.0% or less, and most preferably 0.6% or less. The lower limit of the content of the compound having a molecular weight of 700 to 3000 is not limited, and is, for example, 0.01%.

[0522] The content of the compound having a molecular weight of 700 to 3000 is a value calculated from the peak area of ​​GPC.

[0523] The compound having a molecular weight of 700 to 3000 is not limited, and all compounds having the above molecular weight are included.

[0524] In the first composition of the present invention, the content of the compound having a molecular weight of 400 to 3000 is preferably 3.7% or less relative to the fluorinated polymer. By making the content of the compound having a molecular weight of 400 to 3000 within the above range, the dispersibility is further improved. It is preferably 3.2% or less, more preferably 2.7% or less, further preferably 1.7% or less, particularly preferably 1.2% or less, particularly preferably 1.0% or less, and most preferably 0.6% or less. The lower limit of the content of the compound having a molecular weight of 400 to 3000 is not limited, and is, for example, 0.01%.

[0525] The content of the compound having a molecular weight of 400 to 3000 is a value calculated from the peak area of ​​GPC.

[0526] The compound having a molecular weight of 400 to 3000 is not limited, and all compounds having the above molecular weight are included.

[0527] In the first composition of the present invention, the content of the compound having a molecular weight of 700 or more and less than 10,000 is preferably 5.0% or less relative to the fluorinated polymer. By making the content of the compound having a molecular weight of 700 or more and less than 10,000 within the above range, the dispersibility is further improved. It is preferably 4.0% or less, more preferably 2.0% or less, further preferably 1.5% or less, particularly preferably 1.0% or less, and most preferably 0.6% or less. The lower limit of the content of the compound having a molecular weight of 700 or more and less than 10,000 is not limited, and is, for example, 0.01%.

[0528] The content of the compound having a molecular weight of 700 or more and less than 10,000 is a value calculated from the peak area of ​​GPC.

[0529] The compound having a molecular weight of 700 or more and less than 10,000 is not limited, and all compounds having the above molecular weight are included.

[0530] In the first composition of the present invention, from the perspective of dispersibility, the content of the compound having a molecular weight of 700 or more and less than 3000 is preferably 3.5% or less, more preferably 3.0% or less, further preferably 2.5% or less, further preferably 2.0% or less, particularly preferably 1.5% or less, particularly preferably 1.0% or less, and most preferably 0.6% or less relative to the fluorinated polymer. The lower limit of the content of the compound having a molecular weight of 700 or more and less than 3000 is not limited, and is, for example, 0.01%.

[0531] The content of the compound having a molecular weight of 700 or more and less than 3,000 is a value calculated from the peak area of ​​GPC.

[0532] The compound having a molecular weight of 700 or more and less than 3000 is not limited, and all compounds having the above molecular weight are included.

[0533] In the first composition of the present invention, from the perspective of dispersibility, the content of the compound having a molecular weight of 700 or more and less than 5000 is preferably 4.0% or less, more preferably 3.5% or less, further preferably 3.0% or less, still further preferably 2.0% or less, particularly further preferably 1.5% or less, particularly preferably 1.0% or less, and most preferably 0.6% or less, relative to the fluorinated polymer. The lower limit of the content of the compound having a molecular weight of 700 or more and less than 5000 is not limited, and is, for example, 0.01%.

[0534] The content of the compound having a molecular weight of 700 or more and less than 5,000 is a value calculated from the peak area of ​​GPC.

[0535] The compound having a molecular weight of 700 or more and less than 5000 is not limited, and all compounds having the above molecular weight are included.

[0536] In the first composition of the present invention, from the perspective of dispersibility, the content of the compound having a molecular weight of 700 or more and less than 20,000 is preferably 11.0% or less, more preferably 10.0% or less, further preferably 9.0% or less, and particularly preferably 7.8% or less relative to the fluorinated polymer. The lower limit of the content of the compound having a molecular weight of 700 or more and less than 20,000 is not limited, and is, for example, 0.01%. The content of the compound having a molecular weight of 700 or more and less than 20,000 is a value calculated from the peak area of ​​GPC.

[0537] The compound having a molecular weight of 700 or more and less than 20,000 is not limited, and all compounds having the above molecular weight are included.

[0538] The first composition of the present invention may be used as it is, or may be used after dilution or concentration.

[0539] In addition, the fluorinated polymer can be separated from the first composition of the present invention and used. For example, the fluorinated polymer can be separated and used as a dispersant. The dispersant can be used, for example, when the polymer is polymerized, or can be used as a dispersant added after the polymer is polymerized.

[0540] In particular, a fluorinated polymer other than the above-mentioned fluorinated polymer can be produced by polymerizing a fluorinated monomer in the presence of the fluorinated polymer obtained from the first composition of the present invention.

[0541] The above-mentioned fluorine-containing monomer is not particularly limited as long as it is a monomer having at least one fluorine or fluoroalkyl group, and may include, for example, trifluoroethylene, tetrafluoroethylene (TFE), vinylidene fluoride (VdF), vinyl fluoride (VF), chlorotrifluoroethylene (CTFE), hexafluoropropylene (HFP), hexafluoroisobutylene, perfluoroalkylethylene, fluorovinyl ether (FVE), CH2=CFCF3, CHF=CHCF3 (E body), CHF=CHCF3 (Z body), etc.

[0542] Examples of the other fluorine-containing polymers include polytetrafluoroethylene (PTFE), copolymers of TFE and other monomers copolymerizable with TFE (fluorine-containing monomers such as vinylidene fluoride, hexafluoropropylene, chlorotrifluoroethylene, and perfluoro(alkyl vinyl ether), hydrocarbon olefins such as ethylene, propylene, and isobutylene, and alkyl vinyl ethers) (for example, tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoro(alkyl vinyl ether) copolymer (PFA), and ethylene-tetrafluoroethylene copolymer (ETFE)), fluororesins such as polyvinylidene fluoride (PVDF), polytrifluorochloroethylene (PCTFE), and ethylene-chlorotrifluoroethylene (ECTFE), vinylidene fluoride-based rubbers (FKM) such as vinylidene fluoride-hexafluoropropylene copolymers, tetrafluoroethylene-propylene rubbers (FEPM), and fluororubbers such as tetrafluoroethylene-perfluoromethyl vinyl ether rubber (FFKM), and fluorine-containing elastomers.

[0543] The PTFE may be a homopolymer of TFE, or may be a modified PTFE containing 99.0% by mass or more of TFE and 1.0% by mass or less of a modifying monomer.

[0544] The other fluorine-containing polymer is preferably at least one selected from the group consisting of PTFE and a melt-processable fluorine resin containing 60.0 to 98.0 mass % of TFE units and 2.0 to 40.0 mass % of other monomers, and PTFE is particularly preferred.

[0545] The first composition of the present invention can be used as a coating agent. The first composition of the present invention has excellent dispersibility (property of dispersing other components) because the content of the compound having a molecular weight of 700 to 3000 is reduced.

[0546] When the first composition of the present invention is a coating agent, the composition may contain the above-mentioned other fluorinated polymer, water, and the like.

[0547] The present invention also relates to a composition (hereinafter also referred to as "the second composition of the present invention"), characterized in that it contains water and a polymer (hereinafter also referred to as "polymer α"), in which the proportion of hydrogen atoms bonded to carbon atoms replaced by fluorine atoms is greater than 50%, and the polymer contains ionic groups and has an ion exchange rate of less than 53. In the composition, the content of compounds with a molecular weight of greater than 700 and less than 3000 is less than 3.5% relative to the polymer α.

[0548] The second composition of the present invention may be an aqueous solution.

[0549] In the second composition of the present invention, the content of the compound having a molecular weight of 400 to 3000 is preferably 3.7% or less based on the polymer α.

[0550] In the second composition of the present invention, the content of the compound having a molecular weight of 700 or more and less than 10,000 is preferably 5.0% or less based on the polymer α.

[0551] The second composition of the present invention has a reduced amount of low molecular weight substances, and therefore, when used as a dispersant in a polymer dispersion, can improve dispersibility (property of dispersing other components).

[0552] In addition, the coating agent obtained from the second composition of the present invention is excellent in transparency, water resistance and antireflection property.

[0553] The second composition of the present invention can be suitably produced by the second production method of the present invention.

[0554] The second composition of the present invention contains water. The content of water is not limited, but is preferably an amount in which the fluorine-containing polymer can be dispersed or dissolved.

[0555] Examples of the polymer α in the second composition of the present invention include the polymer α described in the second production method of the present invention. In addition, all preferred embodiments can be adopted.

[0556] The polymer α is preferably a water-soluble polymer.

[0557] In the second composition of the present invention, the content of the polymer α is not particularly limited, and may be, for example, 0.1% by mass to 10.0% by mass based on the composition.

[0558] The second composition of the present invention may be a composition obtained by diluting or concentrating the composition obtained by the second production method of the present invention.

[0559] The second composition of the present invention may contain a single polymer α, or may contain two or more different polymers α.

[0560] In the second composition of the present invention, the content of the compound having a molecular weight of 700 to 3000 is 3.5% or less relative to the polymer α. By making the content of the compound having a molecular weight of 700 to 3000 within the above range, the dispersibility is excellent. It is preferably 3.0% or less, more preferably 2.5% or less, further preferably 1.5% or less, particularly preferably 1.0% or less, and most preferably 0.6% or less. The lower limit of the content of the compound having a molecular weight of 700 to 3000 is not limited, for example, it is 0.01%.

[0561] The content of the compound having a molecular weight of 700 to 3000 is a value calculated from the peak area of ​​GPC.

[0562] The compound having a molecular weight of 700 to 3000 is not limited, and all compounds having the above molecular weight are included.

[0563] In the second composition of the present invention, the content of the compound having a molecular weight of 400 to 3000 is preferably 3.7% or less relative to polymer α. By making the content of the compound having a molecular weight of 400 to 3000 within the above range, the dispersibility is further improved. It is preferably 3.2% or less, more preferably 2.7% or less, further preferably 1.7% or less, particularly preferably 1.2% or less, particularly preferably 1.0% or less, and most preferably 0.6% or less. The lower limit of the content of the compound having a molecular weight of 400 to 3000 is not limited, and is, for example, 0.01%.

[0564] The content of the compound having a molecular weight of 400 to 3000 is a value calculated from the peak area of ​​GPC.

[0565] The compound having a molecular weight of 400 to 3000 is not limited, and all compounds having the above molecular weight are included.

[0566] In the second composition of the present invention, the content of the compound having a molecular weight of 700 or more and less than 10,000 is preferably 5.0% or less relative to the polymer α. By making the content of the compound having a molecular weight of 700 or more and less than 10,000 within the above range, the dispersibility is further improved. It is preferably 4.0% or less, more preferably 2.0% or less, further preferably 1.5% or less, particularly preferably 1.0% or less, and most preferably 0.6% or less. The lower limit of the content of the compound having a molecular weight of 700 or more and less than 10,000 is not limited, and is, for example, 0.01%.

[0567] The content of the compound having a molecular weight of 700 or more and less than 10,000 is a value calculated from the peak area of ​​GPC.

[0568] The compound having a molecular weight of 700 or more and less than 10,000 is not limited, and all compounds having the above molecular weight are included.

[0569] In the second composition of the present invention, from the perspective of dispersibility, the content of the compound having a molecular weight of 700 or more and less than 3000 is preferably 3.5% or less, more preferably 3.0% or less, further preferably 2.5% or less, still further preferably 2.0% or less, particularly further preferably 1.5% or less, particularly preferably 1.0% or less, and most preferably 0.6% or less, relative to the polymer α. The lower limit of the content of the compound having a molecular weight of 700 or more and less than 3000 is not limited, and is, for example, 0.01%.

[0570] The content of the compound having a molecular weight of 700 or more and less than 3,000 is a value calculated from the peak area of ​​GPC.

[0571] The compound having a molecular weight of 700 or more and less than 3000 is not limited, and all compounds having the above molecular weight are included.

[0572] In the second composition of the present invention, from the perspective of dispersibility, the content of the compound having a molecular weight of 700 or more and less than 5000 is preferably 4.0% or less, more preferably 3.5% or less, further preferably 3.0% or less, still further preferably 2.0% or less, particularly further preferably 1.5% or less, particularly preferably 1.0% or less, and most preferably 0.6% or less, relative to the polymer α. The lower limit of the content of the compound having a molecular weight of 700 or more and less than 5000 is not limited, and is, for example, 0.01%.

[0573] The content of the compound having a molecular weight of 700 or more and less than 5,000 is a value calculated from the peak area of ​​GPC.

[0574] The compound having a molecular weight of 700 or more and less than 5000 is not limited, and all compounds having the above molecular weight are included.

[0575] In the second composition of the present invention, from the perspective of dispersibility, the content of the compound having a molecular weight of 700 or more and less than 20,000 is preferably 11.0% or less, more preferably 10.0% or less, further preferably 9.0% or less, and further preferably 7.8% or less relative to the polymer α. The lower limit of the content of the compound having a molecular weight of 700 or more and less than 20,000 is not limited, and is, for example, 0.01%.

[0576] The content of the compound having a molecular weight of 700 or more and less than 20,000 is a value calculated from the peak area of ​​GPC.

[0577] The compound having a molecular weight of 700 or more and less than 20,000 is not limited, and all compounds having the above molecular weight are included.

[0578] The second composition of the present invention may be used as it is, or may be used after dilution or concentration.

[0579] In addition, the polymer α can be separated from the second composition of the present invention and used. For example, the polymer α can be separated and used as a dispersant. The dispersant can be used, for example, when the polymer is polymerized, or can be used as a dispersant added after the polymer is polymerized.

[0580] In particular, a polymer other than the polymer α can be produced by polymerizing a fluorinated monomer in the presence of the polymer α obtained from the second composition of the present invention.

[0581] The above-mentioned fluorine-containing monomer is not particularly limited as long as it is a monomer having at least one fluorine or fluoroalkyl group, and may include, for example, trifluoroethylene, tetrafluoroethylene (TFE), vinylidene fluoride (VdF), vinyl fluoride (VF), chlorotrifluoroethylene (CTFE), hexafluoropropylene (HFP), hexafluoroisobutylene, perfluoroalkylethylene and fluorovinyl ether (FVE), CH2=CFCF3, CHF=CHCF3 (E body), CHF=CHCF3 (Z body), etc.

[0582] Examples of the other polymers include polytetrafluoroethylene (PTFE), copolymers of TFE and other monomers copolymerizable with TFE (fluorinated monomers such as vinylidene fluoride, hexafluoropropylene, chlorotrifluoroethylene, and perfluoro(alkyl vinyl ether), hydrocarbon olefins such as ethylene, propylene, and isobutylene, and alkyl vinyl ethers) (e.g., tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoro(alkyl vinyl ether) copolymer (PFA), and ethylene-tetrafluoroethylene copolymer (ETFE)), fluororesins such as polyvinylidene fluoride (PVDF), polytrifluorochloroethylene (PCTFE), and ethylene-chlorotrifluoroethylene (ECTFE), vinylidene fluoride-based rubbers (FKM) such as vinylidene fluoride-hexafluoropropylene copolymers, tetrafluoroethylene-propylene rubbers (FEPM), and fluororubbers such as tetrafluoroethylene-perfluoromethyl vinyl ether rubber (FFKM), and fluorine-containing elastomers.

[0583] The PTFE may be a homopolymer of TFE, or may be a modified PTFE containing 99.0% by mass or more of TFE and 1.0% by mass or less of a modifying monomer.

[0584] The other polymer is preferably at least one selected from the group consisting of PTFE and a melt-processable fluororesin containing 60.0 to 98.0% by mass of TFE units and 2.0 to 40.0% by mass of other monomers, and PTFE is particularly preferred.

[0585] The second composition of the present invention can be used as a coating agent. The second composition of the present invention has excellent dispersibility (property of dispersing other components) because the content of the compound having a molecular weight of 700 to 3000 is reduced.

[0586] When the second composition of the present invention is a coating agent, the composition may contain the above-mentioned other polymer, water, and the like.

[0587] The present invention also relates to a composition (hereinafter also referred to as "the third composition of the present invention"), characterized in that it contains water and a water-soluble polymer in which the hydrogen atoms bonded to carbon atoms are replaced by fluorine atoms in a ratio of 50% or more, and in which the content of compounds with a molecular weight of 700 to 3000 is less than 3.5% relative to the above-mentioned water-soluble polymer.

[0588] The third composition of the present invention may be an aqueous solution.

[0589] In the third composition of the present invention, the content of the compound having a molecular weight of 400 to 3000 is preferably 3.7% or less based on the water-soluble polymer.

[0590] The content of the compound having a molecular weight of 700 or more and less than 10,000 is preferably 5.0% or less based on the water-soluble polymer.

[0591] The third composition of the present invention has reduced low molecular weight substances, and therefore, when used as a dispersant in a polymer dispersion, it is possible to improve dispersibility (property of dispersing other components).

[0592] In addition, the coating agent obtained from the third composition of the present invention is excellent in transparency, water resistance and antireflection property.

[0593] The third composition of the present invention can be suitably produced by the third production method of the present invention.

[0594] The third composition of the present invention contains water. The content of water is not limited, but is preferably an amount in which the water-soluble polymer can be dispersed or dissolved, and is preferably an amount in which the water-soluble polymer can be dissolved.

[0595] Examples of the water-soluble polymer in the third composition of the present invention include the water-soluble polymers described in the third production method of the present invention. In addition, all preferred embodiments can be adopted.

[0596] In the third composition of the present invention, the content of the water-soluble polymer is not particularly limited, and may be, for example, 0.1% by mass to 10.0% by mass based on the composition.

[0597] The third composition of the present invention may be a composition obtained by diluting or concentrating the composition obtained by the third production method of the present invention.

[0598] The third composition of the present invention may contain a single water-soluble polymer or may contain two or more different water-soluble polymers.

[0599] In the third composition of the present invention, the content of the water-soluble polymer is not particularly limited, and may be, for example, 0.1% by mass to 10.0% by mass based on the composition.

[0600] The third composition of the present invention may be a composition obtained by diluting or concentrating the composition obtained by the third production method of the present invention.

[0601] The third composition of the present invention may contain a single water-soluble polymer or may contain two or more different water-soluble polymers.

[0602] In the third composition of the present invention, the content of the compound having a molecular weight of 700 to 3000 is 3.5% or less relative to the water-soluble polymer. By making the content of the compound having a molecular weight of 700 to 3000 within the above range, the dispersibility is excellent. It is preferably 3.0% or less, more preferably 2.5% or less, further preferably 1.5% or less, particularly preferably 1.0% or less, and most preferably 0.6% or less. The lower limit of the content of the compound having a molecular weight of 700 to 3000 is not limited, and is, for example, 0.01%.

[0603] The content of the compound having a molecular weight of 700 to 3000 is a value calculated from the peak area of ​​GPC.

[0604] The compound having a molecular weight of 700 to 3000 is not limited, and all compounds having the above molecular weight are included.

[0605] In the third composition of the present invention, the content of the compound having a molecular weight of 400 to 3000 is preferably 3.7% or less relative to the water-soluble polymer. By making the content of the compound having a molecular weight of 400 to 3000 within the above range, the dispersibility is further improved. It is preferably 3.2% or less, and more preferably 2.7% or less. It is further preferably 1.7% or less, further preferably 1.2% or less, particularly preferably 1.0% or less, and most preferably 0.6% or less. The lower limit of the content of the compound having a molecular weight of 400 to 3000 is not limited, and is, for example, 0.01%.

[0606] The content of the compound having a molecular weight of 400 to 3000 is a value calculated from the peak area of ​​GPC.

[0607] The compound having a molecular weight of 400 to 3000 is not limited, and all compounds having the above molecular weight are included.

[0608] In the third composition of the present invention, the content of the compound having a molecular weight of 700 or more and less than 10,000 is preferably 5.0% or less relative to the water-soluble polymer. By making the content of the compound having a molecular weight of 700 or more and less than 10,000 within the above range, the dispersibility is further improved. It is preferably 4.0% or less, more preferably 2.0% or less, further preferably 1.5% or less, particularly preferably 1.0% or less, and most preferably 0.6% or less. The lower limit of the content of the compound having a molecular weight of 700 or more and less than 10,000 is not limited, and is, for example, 0.01%.

[0609] The content of the compound having a molecular weight of 700 or more and less than 10,000 is a value calculated from the peak area of ​​GPC.

[0610] The compound having a molecular weight of 700 or more and less than 10,000 is not limited, and all compounds having the above molecular weight are included.

[0611] In the third composition of the present invention, from the perspective of dispersibility, the content of the compound having a molecular weight of 700 or more and less than 3000 is preferably 3.5% or less, more preferably 3.0% or less, further preferably 2.5% or less, still further preferably 2.0% or less, particularly further preferably 1.5% or less, particularly preferably 1.0% or less, and most preferably 0.6% or less relative to the water-soluble polymer. The lower limit of the content of the compound having a molecular weight of 700 or more and less than 3000 is not limited, and is, for example, 0.01%.

[0612] The content of the compound having a molecular weight of 700 or more and less than 3,000 is a value calculated from the peak area of ​​GPC.

[0613] The compound having a molecular weight of 700 or more and less than 3000 is not limited, and all compounds having the above molecular weight are included.

[0614] In the third composition of the present invention, from the perspective of dispersibility, the content of the compound having a molecular weight of 700 or more and less than 5000 is preferably 4.0% or less, more preferably 3.5% or less, further preferably 3.0% or less, still further preferably 2.0% or less, particularly further preferably 1.5% or less, particularly preferably 1.0% or less, and most preferably 0.6% or less relative to the water-soluble polymer. The lower limit of the content of the compound having a molecular weight of 700 or more and less than 5000 is not limited, and is, for example, 0.01%.

[0615] The content of the compound having a molecular weight of 700 or more and less than 5,000 is a value calculated from the peak area of ​​GPC.

[0616] The compound having a molecular weight of 700 or more and less than 5000 is not limited, and all compounds having the above molecular weight are included.

[0617] In the third composition of the present invention, from the perspective of dispersibility, the content of the compound having a molecular weight of 700 or more and less than 20,000 is preferably 11.0% or less, more preferably 10.0% or less, further preferably 9.0% or less, and particularly preferably 7.8% or less relative to the water-soluble polymer. The lower limit of the content of the compound having a molecular weight of 700 or more and less than 20,000 is not limited, and is, for example, 0.01%.

[0618] The content of the compound having a molecular weight of 700 or more and less than 20,000 is a value calculated from the peak area of ​​GPC.

[0619] The compound having a molecular weight of 700 or more and less than 20,000 is not limited, and all compounds having the above molecular weight are included.

[0620] The third composition of the present invention may be used as it is, or may be used after dilution or concentration.

[0621] In addition, the water-soluble polymer can be separated from the third composition of the present invention and used. For example, the water-soluble polymer can be separated and used as a dispersant. The dispersant can be used, for example, when the polymer is polymerized, or can be used as a dispersant added after the polymer is polymerized.

[0622] In particular, a fluorinated monomer may be polymerized in the presence of a water-soluble polymer obtained from the third composition of the present invention to produce a polymer other than the water-soluble polymer.

[0623] The above-mentioned fluorine-containing monomer is not particularly limited as long as it is a monomer having at least one fluorine or fluoroalkyl group, and may include, for example, trifluoroethylene, tetrafluoroethylene (TFE), vinylidene fluoride (VdF), vinyl fluoride (VF), chlorotrifluoroethylene (CTFE), hexafluoropropylene (HFP), hexafluoroisobutylene, perfluoroalkylethylene, and fluorovinyl ether (FVE), CH2=CFCF3, CHF=CHCF3 (E body), CHF=CHCF3 (Z body), etc.

[0624] Examples of the other polymers include polytetrafluoroethylene (PTFE), copolymers of TFE and other monomers copolymerizable with TFE (fluorinated monomers such as vinylidene fluoride, hexafluoropropylene, chlorotrifluoroethylene, and perfluoro(alkyl vinyl ether), hydrocarbon olefins such as ethylene, propylene, and isobutylene, and alkyl vinyl ethers) (e.g., tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoro(alkyl vinyl ether) copolymer (PFA), and ethylene-tetrafluoroethylene copolymer (ETFE)), fluororesins such as polyvinylidene fluoride (PVDF), polytrifluorochloroethylene (PCTFE), and ethylene-chlorotrifluoroethylene (ECTFE), vinylidene fluoride-based rubbers (FKM) such as vinylidene fluoride-hexafluoropropylene copolymers, tetrafluoroethylene-propylene rubbers (FEPM), and fluororubbers such as tetrafluoroethylene-perfluoromethyl vinyl ether rubber (FFKM), and fluorine-containing elastomers.

[0625] The PTFE may be a homopolymer of TFE, or may be a modified PTFE containing 99.0% by mass or more of TFE and 1.0% by mass or less of a modifying monomer.

[0626] The other polymer is preferably at least one selected from the group consisting of PTFE and a melt-processable fluororesin containing 60.0 to 98.0% by mass of TFE units and 2.0 to 40.0% by mass of other monomers, and PTFE is particularly preferred.

[0627] The third composition of the present invention can be used as a coating agent. The third composition of the present invention has excellent dispersibility (property of dispersing other components) because the content of the compound having a molecular weight of 700 to 3000 is reduced.

[0628] When the third composition of the present invention is a coating agent, the composition may contain the above-mentioned other polymer, water, and the like.

[0629] The present invention also relates to a composition (hereinafter also referred to as "the fourth composition of the present invention"), characterized in that it contains water and a fluorine-containing polymer, wherein the fluorine-containing polymer is a polymer containing a structural unit M3 derived from a monomer represented by the general formula (1),

[0630] CX2=CY(-CZ2-O-Rf-A) (1)

[0631] (wherein, X is the same or different and is -H or -F, Y is -H, -F, alkyl or fluorinated alkyl, and Z is the same or different and is -H, -F, alkyl or fluorinated alkyl. Rf is a fluorinated alkylene group having 1 to 40 carbon atoms, or a fluorinated alkylene group having 2 to 100 carbon atoms and having an ether bond. A is -COOM, -SO3M, -OSO3M or -C(CF3)2OM (M is -H, a metal atom, -NR 7 4. an imidazolium which may be substituted, a pyridinium which may be substituted, or a phosphonium which may be substituted, R 7 is H or an organic group). wherein at least one of X, Y and Z contains a fluorine atom.

[0632] The content of dimers and trimers of monomers forming structural units constituting the fluorinated polymer is 2.0% or less based on the fluorinated polymer.

[0633] The fourth composition of the present invention may be an aqueous solution.

[0634] Since the fourth composition of the present invention has a reduced content of dimers and trimers, a polymer having a reduced content of dimers and trimers can be obtained by using the fourth composition of the present invention for polymerization of monomers in an aqueous medium.

[0635] The fourth composition of the present invention can be suitably produced by the first production method of the present invention.

[0636] In the fluorine-containing polymer, the ratio in which hydrogen atoms bonded to carbon atoms are replaced with fluorine atoms is preferably 50% or more.

[0637] The fluorinated polymer preferably contains an ionic group, and the ion exchange rate is preferably 53 or less.

[0638] In the fluorine-containing polymer, the ratio in which hydrogen atoms bonded to carbon atoms are replaced with fluorine atoms is preferably 50% or more.

[0639] The above-mentioned fluorine-containing polymer is preferably a water-soluble polymer.

[0640] The fourth composition of the present invention contains water. The content of water is not limited as long as it is an amount in which the fluorine-containing polymer can be dispersed or dissolved.

[0641] Examples of the fluorinated polymer in the fourth composition of the present invention include the fluorinated polymers described in the first production method of the present invention. In addition, all preferred embodiments may be adopted.

[0642] In the fourth composition of the present invention, the content of the fluorine-containing polymer is not particularly limited, and may be, for example, 0.1% to 10.0% based on the composition.

[0643] The fourth composition of the present invention may be a composition obtained by diluting or concentrating the composition obtained by the first production method of the present invention.

[0644] The fourth composition of the present invention may contain a single fluorinated polymer or may contain two or more different fluorinated polymers.

[0645] In the fourth composition of the present invention, as dimers and trimers, preferably dimers and trimers of monomers represented by general formula (I) (hereinafter sometimes referred to as monomers (I)). Dimers and trimers can be polymers formed from one monomer (I) as monomer (I) represented by general formula (I), or copolymers formed from two or more monomers (I) having different structures. In addition, as dimers and trimers, dimers and trimers of monomers described above as monomers forming preferred structural units constituting fluorinated polymers can be cited.

[0646] The content of the dimer and trimer in the fourth composition of the present invention is preferably 2.0% or less, 1.5% or less, 1.0% or less, 0.1% or less, 0.01% or less, 0.001% or less, and 0.0001% or less relative to the fluorine-containing polymer.

[0647] The method for measuring the content of dimer and trimer in the composition is as described above.

[0648] In the fourth composition of the present invention, the content of the compound having a molecular weight of 700 or more and less than 1000 is preferably 2.0% or less, more preferably 1.5% or less, further preferably 1.0% or less, and further preferably 0.6% or less relative to the fluorinated polymer. The lower limit of the content of the compound having a molecular weight of 700 or more and less than 1000 is not limited, and is, for example, 0.01%.

[0649] In the fourth composition of the present invention, the content of the compound having a molecular weight of 700 to 3000 is preferably 3.5% or less, more preferably 3.0% or less, further preferably 2.5% or less, still further preferably 1.5% or less, particularly preferably 1.0% or less, and most preferably 0.6% or less relative to the fluorinated polymer. The lower limit of the content of the compound having a molecular weight of 700 to 3000 is not limited, and is, for example, 0.01%.

[0650] In the fourth composition of the present invention, the content of the compound having a molecular weight of 400 to 3000 is preferably 3.7% or less, more preferably 3.2% or less, further preferably 2.7% or less, still further preferably 1.7% or less, particularly further preferably 1.2% or less, particularly preferably 1.0% or less, and most preferably 0.6% or less, relative to the fluorinated polymer. The lower limit of the content of the compound having a molecular weight of 400 to 3000 is not limited, and is, for example, 0.01%.

[0651] The contents of the compound having a molecular weight of 700 or more and less than 1000, the compound having a molecular weight of 700 or more and 3000 or less, and the compound having a molecular weight of 400 or more and 3000 or less are values ​​calculated from the peak area of ​​GPC.

[0652] The compounds having a molecular weight of 700 or more and less than 1000, the compounds having a molecular weight of 700 or more and 3000 or less, and the compounds having a molecular weight of 400 or more and 3000 or less are not limited, and all compounds having the above molecular weights are included.

[0653] In particular, a polymer other than the above-mentioned fluorinated polymer can be produced by polymerizing a fluorinated monomer in the presence of the fluorinated polymer obtained from the fourth composition of the present invention.

[0654] The above-mentioned fluorine-containing monomer is not particularly limited as long as it is a monomer having at least one fluorine or fluoroalkyl group, and may include, for example, trifluoroethylene, tetrafluoroethylene (TFE), vinylidene fluoride (VdF), vinyl fluoride (VF), chlorotrifluoroethylene (CTFE), hexafluoropropylene (HFP), hexafluoroisobutylene, perfluoroalkylethylene and fluorovinyl ether (FVE), CH2=CFCF3, CHF=CHCF3 (E body), CHF=CHCF3 (Z body), etc.

[0655] Examples of the other polymers include polytetrafluoroethylene (PTFE), copolymers of TFE and other monomers copolymerizable with TFE (fluorinated monomers such as vinylidene fluoride, hexafluoropropylene, chlorotrifluoroethylene, and perfluoro(alkyl vinyl ether), hydrocarbon olefins such as ethylene, propylene, and isobutylene, and alkyl vinyl ethers) (e.g., tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoro(alkyl vinyl ether) copolymer (PFA), and ethylene-tetrafluoroethylene copolymer (ETFE)), fluororesins such as polyvinylidene fluoride (PVDF), polytrifluorochloroethylene (PCTFE), and ethylene-chlorotrifluoroethylene (ECTFE), vinylidene fluoride-based rubbers (FKM) such as vinylidene fluoride-hexafluoropropylene copolymers, tetrafluoroethylene-propylene rubbers (FEPM), and fluororubbers such as tetrafluoroethylene-perfluoromethyl vinyl ether rubber (FFKM), and fluorine-containing elastomers.

[0656] The PTFE may be a homopolymer of TFE, or may be a modified PTFE containing 99.0% by mass or more of TFE and 1.0% by mass or less of a modifying monomer.

[0657] The other polymer is preferably at least one selected from the group consisting of PTFE and a melt-processable fluororesin containing 60.0 to 98.0% by mass of TFE units and 2.0 to 40.0% by mass of other monomers, and PTFE is particularly preferred.

[0658] The fourth composition of the present invention can be used as a coating agent. When the fourth composition of the present invention is a coating agent, the composition may contain the above-mentioned other polymer, water, and the like.

[0659] The present invention also relates to a composition (hereinafter also referred to as "the fifth composition of the present invention"), characterized in that it contains water and a polymer α, in which the proportion of hydrogen atoms bonded to carbon atoms replaced by fluorine atoms is more than 50%, and the polymer α contains ionic groups, has an ion exchange rate of less than 53, and the content of dimers and trimers of monomers that form structural units constituting the above-mentioned polymer α is less than 2.0% relative to the above-mentioned polymer α.

[0660] The fifth composition of the present invention may be an aqueous solution.

[0661] Since the fifth composition of the present invention has a reduced content of dimers and trimers, a polymer having a reduced content of dimers and trimers can be obtained by using the fifth composition of the present invention for polymerization of monomers in an aqueous medium.

[0662] The fifth composition of the present invention can be suitably produced by the second production method of the present invention.

[0663] The fifth composition of the present invention contains water. The content of water is not limited as long as it is an amount in which the polymer α can be dispersed or dissolved.

[0664] Examples of the polymer α in the fifth composition of the present invention include the polymer α described in the second production method of the present invention. In addition, all preferred embodiments can be adopted.

[0665] The polymer α is preferably a water-soluble polymer.

[0666] In the fifth composition of the present invention, the content of the polymer α is not particularly limited, and may be, for example, 0.1% by mass to 10.0% by mass based on the composition.

[0667] The fifth composition of the present invention may be a composition obtained by diluting or concentrating the composition obtained by the second production method of the present invention.

[0668] The fifth composition of the present invention may contain a single polymer α, or may contain two or more different polymers α.

[0669] In the fifth composition of the present invention, dimers and trimers are preferably dimers and trimers of a monomer represented by the general formula (I) (hereinafter sometimes referred to as monomer (I)). Dimers and trimers may be polymers formed from one monomer (I) as the monomer (I) represented by the general formula (I), or may be polymers formed from two or more monomers (I) having different structures. In addition, dimers and trimers may be dimers and trimers of the monomers described above as monomers forming preferred structural units constituting polymer α.

[0670] The content of the dimer and trimer in the fifth composition of the present invention is preferably 2.0% or less, 1.5% or less, 1.0% or less, 0.1% or less, 0.01% or less, 0.001% or less, and 0.0001% or less relative to the polymer α.

[0671] The method for measuring the content of dimer and trimer in the composition is as described above.

[0672] In the fifth composition of the present invention, the content of the compound having a molecular weight of 700 or more and less than 1000 is preferably 2.0% or less, more preferably 1.5% or less, further preferably 1.0% or less, and further preferably 0.6% or less relative to the polymer α. The lower limit of the content of the compound having a molecular weight of 700 or more and less than 1000 is not limited, and is, for example, 0.01%.

[0673] In the fifth composition of the present invention, the content of the compound having a molecular weight of 700 to 3000 is preferably 3.5% or less, more preferably 3.0% or less, further preferably 2.5% or less, still further preferably 1.5% or less, particularly preferably 1.0% or less, and most preferably 0.6% or less relative to the polymer α. The lower limit of the content of the compound having a molecular weight of 700 to 3000 is not limited, and is, for example, 0.01%.

[0674] In the fifth composition of the present invention, the content of the compound having a molecular weight of 400 to 3000 is preferably 3.7% or less, more preferably 3.2% or less, further preferably 2.7% or less, still further preferably 1.7% or less, particularly further preferably 1.2% or less, particularly preferably 1.0% or less, and most preferably 0.6% or less, relative to the polymer α. The lower limit of the content of the compound having a molecular weight of 400 to 3000 is not limited, and is, for example, 0.01%.

[0675] The contents of the compound having a molecular weight of 700 or more and less than 1000, the compound having a molecular weight of 700 or more and 3000 or less, and the compound having a molecular weight of 400 or more and 3000 or less are values ​​calculated from the peak area of ​​GPC.

[0676] The compounds having a molecular weight of 700 or more and less than 1000, the compounds having a molecular weight of 700 or more and 3000 or less, and the compounds having a molecular weight of 400 or more and 3000 or less are not limited, and all compounds having the above molecular weights are included.

[0677] In particular, a polymer other than the polymer α can be produced by polymerizing a fluorinated monomer in the presence of the polymer α obtained from the fifth composition of the present invention.

[0678] The above-mentioned fluorine-containing monomer is not particularly limited as long as it is a monomer having at least one fluorine or fluoroalkyl group, and may include, for example, trifluoroethylene, tetrafluoroethylene (TFE), vinylidene fluoride (VdF), vinyl fluoride (VF), chlorotrifluoroethylene (CTFE), hexafluoropropylene (HFP), hexafluoroisobutylene, perfluoroalkylethylene, and fluorovinyl ether (FVE), CH2=CFCF3, CHF=CHCF3 (E body), CHF=CHCF3 (Z body), etc.

[0679] Examples of the other polymers include polytetrafluoroethylene (PTFE), copolymers of TFE and other monomers copolymerizable with TFE (fluorinated monomers such as vinylidene fluoride, hexafluoropropylene, chlorotrifluoroethylene, and perfluoro(alkyl vinyl ether), hydrocarbon olefins such as ethylene, propylene, and isobutylene, and alkyl vinyl ethers) (e.g., tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoro(alkyl vinyl ether) copolymer (PFA), and ethylene-tetrafluoroethylene copolymer (ETFE)), fluororesins such as polyvinylidene fluoride (PVDF), polytrifluorochloroethylene (PCTFE), and ethylene-chlorotrifluoroethylene (ECTFE), vinylidene fluoride-based rubbers (FKM) such as vinylidene fluoride-hexafluoropropylene copolymers, tetrafluoroethylene-propylene rubbers (FEPM), and fluororubbers such as tetrafluoroethylene-perfluoromethyl vinyl ether rubber (FFKM), and fluorine-containing elastomers.

[0680] The PTFE may be a homopolymer of TFE, or may be a modified PTFE containing 99.0% by mass or more of TFE and 1.0% by mass or less of a modifying monomer.

[0681] The other polymer is preferably at least one selected from the group consisting of PTFE and a melt-processable fluororesin containing 60.0 to 98.0% by mass of TFE units and 2.0 to 40.0% by mass of other monomers, and PTFE is particularly preferred.

[0682] The fifth composition of the present invention can be used as a coating agent. When the fifth composition of the present invention is a coating agent, the composition may contain the above-mentioned other polymer, water, and the like.

[0683] The present invention also relates to a composition (hereinafter also referred to as "the sixth composition of the present invention"), characterized in that it contains water and a water-soluble polymer in which the hydrogen atoms bonded to carbon atoms are replaced by fluorine atoms in a ratio of more than 50%, and the content of dimers and trimers of monomers that form structural units constituting the above-mentioned water-soluble polymer is less than 2.0% relative to the above-mentioned water-soluble polymer.

[0684] The sixth composition of the present invention may be an aqueous solution.

[0685] Since the sixth composition of the present invention has a reduced content of dimers and trimers, a polymer having a reduced content of dimers and trimers can be obtained by using the sixth composition of the present invention for polymerization of monomers in an aqueous medium.

[0686] The sixth composition of the present invention can be suitably produced by the third production method of the present invention.

[0687] The sixth composition of the present invention contains water. The content of water is not limited, but is preferably an amount in which the water-soluble polymer can be dispersed or dissolved, and is preferably an amount in which the water-soluble polymer can be dissolved.

[0688] Examples of the water-soluble polymer in the sixth composition of the present invention include the water-soluble polymers described in the third production method of the present invention. In addition, all preferred embodiments can be adopted.

[0689] In the sixth composition of the present invention, the content of the water-soluble polymer is not particularly limited, and may be, for example, 0.1% by mass to 10.0% by mass based on the composition.

[0690] The sixth composition of the present invention may be a composition obtained by diluting or concentrating the composition obtained by the third production method of the present invention.

[0691] The sixth composition of the present invention may contain a single water-soluble polymer or may contain two or more different water-soluble polymers.

[0692] In the sixth composition of the present invention, dimers and trimers are preferably dimers and trimers of a monomer represented by the general formula (I) (hereinafter sometimes referred to as monomer (I)). Dimers and trimers may be polymers formed from one monomer (I) as the monomer (I) represented by the general formula (I), or may be polymers formed from two or more monomers (I) having different structures. In addition, dimers and trimers may be dimers and trimers of the monomers described above as monomers forming preferred structural units constituting the water-soluble polymer.

[0693] The content of the dimer and trimer in the sixth composition of the present invention is preferably 2.0% or less, 1.5% or less, 1.0% or less, 0.1% or less, 0.01% or less, 0.001% or less, and 0.0001% or less relative to the water-soluble polymer.

[0694] The method for measuring the content of dimer and trimer in the composition is as described above.

[0695] In the sixth composition of the present invention, the content of the compound having a molecular weight of 700 or more and less than 1000 is preferably 2.0% or less, more preferably 1.5% or less, further preferably 1.0% or less, and further preferably 0.6% or less relative to the water-soluble polymer. The lower limit of the content of the compound having a molecular weight of 700 or more and less than 1000 is not limited, and is, for example, 0.01%.

[0696] In the sixth composition of the present invention, the content of the compound having a molecular weight of 700 to 3000 is preferably 3.5% or less, more preferably 3.0% or less, further preferably 2.5% or less, still further preferably 1.5% or less, particularly preferably 1.0% or less, and most preferably 0.6% or less relative to the water-soluble polymer. The lower limit of the content of the compound having a molecular weight of 700 to 3000 is not limited, and is, for example, 0.01%.

[0697] In the sixth composition of the present invention, the content of the compound having a molecular weight of 400 to 3000 is preferably 3.7% or less, more preferably 3.2% or less, further preferably 2.7% or less, still further preferably 1.7% or less, particularly further preferably 1.2% or less, particularly preferably 1.0% or less, and most preferably 0.6% or less relative to the water-soluble polymer. The lower limit of the content of the compound having a molecular weight of 400 to 3000 is not limited, and is, for example, 0.01%.

[0698] The contents of the compound having a molecular weight of 700 or more and less than 1000, the compound having a molecular weight of 700 or more and 3000 or less, and the compound having a molecular weight of 400 or more and 3000 or less are values ​​calculated from the peak area of ​​GPC.

[0699] The compounds having a molecular weight of 700 or more and less than 1000, the compounds having a molecular weight of 700 or more and 3000 or less, and the compounds having a molecular weight of 400 or more and 3000 or less are not limited, and all compounds having the above molecular weights are included.

[0700] In particular, a polymer other than the water-soluble polymer can be produced by polymerizing a fluorinated monomer in the presence of a water-soluble polymer obtained from the sixth composition of the present invention.

[0701] The above-mentioned fluorine-containing monomer is not particularly limited as long as it is a monomer having at least one fluorine or fluoroalkyl group, and may include, for example, trifluoroethylene, tetrafluoroethylene (TFE), vinylidene fluoride (VdF), vinyl fluoride (VF), chlorotrifluoroethylene (CTFE), hexafluoropropylene (HFP), hexafluoroisobutylene, perfluoroalkylethylene, and fluorovinyl ether (FVE), CH2=CFCF3, CHF=CHCF3 (E body), CHF=CHCF3 (Z body), etc.

[0702] Examples of the other polymers include polytetrafluoroethylene (PTFE), copolymers of TFE and other monomers copolymerizable with TFE (fluorinated monomers such as vinylidene fluoride, hexafluoropropylene, chlorotrifluoroethylene, and perfluoro(alkyl vinyl ether), hydrocarbon olefins such as ethylene, propylene, and isobutylene, and alkyl vinyl ethers) (e.g., tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoro(alkyl vinyl ether) copolymer (PFA), and ethylene-tetrafluoroethylene copolymer (ETFE)), fluororesins such as polyvinylidene fluoride (PVDF), polytrifluorochloroethylene (PCTFE), and ethylene-chlorotrifluoroethylene (ECTFE), vinylidene fluoride-based rubbers (FKM) such as vinylidene fluoride-hexafluoropropylene copolymers, tetrafluoroethylene-propylene rubbers (FEPM), and fluororubbers such as tetrafluoroethylene-perfluoromethyl vinyl ether rubber (FFKM), and fluorine-containing elastomers.

[0703] The PTFE may be a homopolymer of TFE, or may be a modified PTFE containing 99.0% by mass or more of TFE and 1.0% by mass or less of a modifying monomer.

[0704] The other polymer is preferably at least one selected from the group consisting of PTFE and a melt-processable fluororesin containing 60.0 to 98.0% by mass of TFE units and 2.0 to 40.0% by mass of other monomers, and PTFE is particularly preferred.

[0705] The sixth composition of the present invention can be used as a coating agent. When the sixth composition of the present invention is a coating agent, the composition may contain the above-mentioned other polymer, water, and the like.

[0706] Although the embodiments have been described above, it should be understood that various changes can be made to the embodiments and details without departing from the spirit and scope of the claims.

[0707] Example

[0708] Next, the production method of the present invention will be described with reference to examples, but the production method of the present invention is not limited to the examples.

[0709] Each numerical value in the examples was measured by the following method.

[0710] Method for measuring the weight average molecular weight (Mw), number average molecular weight (Mn), low molecular weight substances with a molecular weight of 700 to 3000, low molecular weight substances with a molecular weight of 400 to 3000, and low molecular weight substances with a molecular weight of 700 to less than 10000

[0711] The Mw, Mn and content of low molecular weight products having a molecular weight of 700 or more and less than 10,000 of the fluorinated polymer (water-soluble polymer) are calculated by gel permeation chromatography (GPC) using monodisperse polyethylene oxide (PEO) and polyethylene glycol (PEG) manufactured by Tosoh Corporation and Agilent as standards.

[0712] Method for determining the content of dimers and trimers in polymers (polymers E, F, etc.)

[0713] (1) Extraction from aqueous solution

[0714] The concentration of the aqueous solution of the polymer was measured, and an amount of the aqueous solution equivalent to 0.2 g of the solid content of the polymer was weighed. Then, the aqueous solution was combined with the water contained in the aqueous solution, and water and methanol were added in a volume ratio of water to methanol of 50 / 50 (volume %) to obtain a mixed solution containing the polymer and water and methanol. Then, the obtained mixed solution was centrifuged at 4000 rpm for 1 hour, and the supernatant containing the polymer was recovered as an extract.

[0715] The extract was analyzed using a liquid chromatography mass spectrometer (Waters, LC-MS ACQUITY UPLC / TQD) to obtain a chromatogram of the extract.

[0716] The content of dimers and trimers of the monomers contained in the extract was determined by converting the integrated value of the peaks derived from dimers and trimers of the monomers appearing in the chromatogram of the extract into the content of dimers and trimers of the monomers using a calibration curve.

[0717] (2) Single-body calibration curve

[0718] Prepare 5 levels of 1 ng / mL to 100 ng / mL methanol standard solutions of monomers with known contents, and measure them using a liquid chromatography mass spectrometer (Waters, LC-MS ACQUITY UPLC / TQD). Plot the relationship between the content of each monomer and the integral value of the peak relative to the content to prepare a calibration curve (first approximation) for each monomer. Next, use the calibration curve (first approximation) of each monomer to prepare calibration curves for dimers and trimers of each monomer.

[0719] Measurement equipment configuration and LC-MS measurement conditions

[0720] [Table 1]

[0721] Table 1

[0722]

[0723] The limit of quantification in this assay setup is 1 ng / mL.

[0724] Concentration of polymer aqueous solution (solid content concentration)

[0725] About 1 g of the polymer aqueous solution was dried in a vacuum dryer at 60°C for 60 minutes, the mass of the heating residue was measured, and the ratio of the mass of the heating residue to the mass of the polymer aqueous solution (1 g) was expressed as a percentage.

[0726] [Synthesis example 1]

[0727] 140 g of the monomer represented by CH2=CFCF2OCF(CF3)COOH, 260 g of water, and APS (0.5 mol%) were added, and the mixture was heated and stirred at 60°C for 17 hours under a nitrogen atmosphere to obtain a fluorinated polymer aqueous solution A-1 containing a fluorinated polymer that is a homopolymer of CH2=CFCF2OCF(CF3)COOH. As a result of GPC analysis, the Mw of the fluorinated polymer was 320,000, the Mn was 100,000, and the content of low molecular weight bodies with a molecular weight of 700 or more and less than 10,000 was 7.1% relative to the fluorinated polymer. In addition, the content of low molecular weight bodies with a molecular weight of 700 or more and 3,000 or less was 3.7% relative to the fluorinated polymer. In addition, the content of low molecular weight bodies with a molecular weight of 400 or more and 3,000 or less was 3.9% relative to the fluorinated polymer.

[0728] [Experimental Example 1]

[0729] Water was added to the fluoropolymer aqueous solution A-1, and after the concentration of the fluoropolymer was adjusted to 2.0% by mass, ultrafiltration was performed using an ultrafiltration membrane (molecular weight cutoff 50,000 Da). Ultrafiltration was performed while water was appropriately injected. The result of GPC analysis of the aqueous solution after ultrafiltration showed that the Mw of the fluoropolymer was 360,000, the Mn was 140,000, and the content of low molecular weight bodies with a molecular weight of 700 or more and less than 10,000 was 0.7% relative to the fluoropolymer. In summary, this method is effective for the removal of low molecular weight bodies. In addition, the content of low molecular weight bodies with a molecular weight of 700 or more and 3,000 or less is less than 0.6% relative to the fluoropolymer. In addition, the content of low molecular weight bodies with a molecular weight of 400 or more and 3,000 or less is less than 0.6% relative to the fluoropolymer.

[0730] [Experimental Example 2]

[0731] 50 g of 10% hydrochloric acid was added to an aqueous solution (solid content 35 g) of 2.0% fluorine-containing polymer prepared by adding water to the fluorine-containing polymer aqueous solution A-1 to precipitate the fluorine-containing polymer, and the precipitated fluorine-containing polymer was dissolved in acetone and injected into n-hexane, separated and vacuum dried to obtain 34.7 g of colorless and transparent polymer. The result of GPC analysis of the obtained polymer showed that the Mw of the fluorine-containing polymer was 350,000 and the Mn was 130,000, and the content of low molecular weight bodies with a molecular weight of 700 or more and less than 10,000 was 6.8% by mass relative to the fluorine-containing polymer. In addition, the content of low molecular weight bodies with a molecular weight of 700 or more and 3,000 or less was 3.6% relative to the fluorine-containing polymer. In addition, the content of low molecular weight bodies with a molecular weight of 400 or more and 3,000 or less was 3.8% relative to the fluorine-containing polymer.

[0732] As can be seen from the above, the conventional method of recovering a fluorinated polymer by precipitating it from an aqueous solution is basically unable to remove low molecular weight substances.

[0733] [Synthesis example 2]

[0734] 10 g of monomer E represented by CF2=CFOCF2CF2COOH, 30 g of water, and APS (6.0 mol% relative to monomer E) were added to a reactor, and heated and stirred at 80°C for 23 hours under a nitrogen atmosphere to obtain a polymer E aqueous solution E-1 containing a polymer E which is a homopolymer of CF2=CFOCF2CF2COOH. The result of GPC analysis of the obtained polymer E aqueous solution E-1 showed that the Mw of polymer E was 7,000 and the Mn was 5,000. The content of low molecular weight bodies with a molecular weight of 700 to 3,000 was 4.6% relative to the fluorinated polymer. In addition, the content of low molecular weight bodies with a molecular weight of 400 to 3,000 was 4.6% relative to the fluorinated polymer.

[0735] [Experimental Example 3]

[0736] Water was added to the obtained polymer E aqueous solution E-1, and the mixture was contacted with a dialysis membrane (molecular weight cutoff 35000Da, polyethylene) at 30°C for filtration to obtain a polymer E aqueous solution E-2. The results of GPC analysis and LC-MS analysis of the obtained polymer E aqueous solution E-2 showed that the Mw of polymer E was 7,000 and the Mn was 6,000, and the content of dimers and trimers was less than 1 mass ppm relative to polymer E. The concentration of the obtained polymer E aqueous solution E-2 was 3.6 mass%. The content of low molecular weight bodies having a molecular weight of 700 to 3000 was less than 0.05% relative to the fluorinated polymer. In addition, the content of low molecular weight bodies having a molecular weight of 400 to 3000 was less than 0.05% relative to the fluorinated polymer.

[0737] [Synthesis example 3]

[0738] 4.1 g of monomer F represented by CF2=CFOCF2CF(CF3)OCF2COOH and 5.2 g of CF2=CF2, and APS (8.8 mol% relative to monomer F) were added, and the mixture was heated and stirred at 80°C for 7 hours under a nitrogen atmosphere to obtain a polymer F aqueous solution F-1 containing a copolymer (polymer F) of monomer F represented by CF2=CFOCF2CF(CF3)OCF2COOH and CF2=CF2. The result of GPC analysis of the obtained polymer F aqueous solution F-1 showed that the Mw of polymer F was 7,000 and the Mn was 4,000. The content of low molecular weight bodies with a molecular weight of 700 to 3,000 was 4.5% relative to the fluorinated polymer. In addition, the content of low molecular weight bodies with a molecular weight of 400 to 3,000 was 4.6% relative to the fluorinated polymer.

[0739] [Experimental Example 4]

[0740] The obtained polymer F aqueous solution F-1 was brought into contact with a dialysis membrane (molecular weight cutoff 35000Da, made of polyethylene) at 30°C and filtered to obtain a polymer F aqueous solution F-2. The obtained polymer F aqueous solution F-2 was subjected to GPC analysis and LC-MS analysis. As a result, the Mw of the polymer F was 9,000 and the Mn was 6,000, and the content of the dimer and trimer was less than 1 mass ppm relative to the polymer F. The concentration of the obtained polymer F aqueous solution F-2 was 2.0 mass %. The content of low molecular weight bodies having a molecular weight of 700 to 3000 was 0.05% or less relative to the fluorinated polymer. In addition, the content of low molecular weight bodies having a molecular weight of 400 to 3000 was 0.05% or less relative to the fluorinated polymer.

[0741] [Synthesis example 3]

[0742] 10 g of monomer E represented by CF2=CFOCF2CF2COOH, 30 g of water, and APS (in batches at 2.5 mol% relative to monomer E) were added to a reactor, and heated and stirred at 50°C for 76 hours under a nitrogen atmosphere to obtain an aqueous solution of polymer E E-1 containing polymer E which is a homopolymer of CF2=CFOCF2CF2COOH. The results of GPC analysis and LC-MS analysis of the obtained aqueous solution of polymer E E-1 showed that the Mw of polymer E was 13,000 and the Mn was 8,000. The content of low molecular weight bodies with a molecular weight of 700 to 3,000 was 3.9% relative to the fluorinated polymer. In addition, the content of low molecular weight bodies with a molecular weight of 400 to 3,000 was 4.0% relative to the fluorinated polymer.

[0743] [Experimental Example 5]

[0744] Water was added to the obtained polymer E aqueous solution E-1, and the mixture was contacted with a dialysis membrane (molecular weight cutoff 35000Da, polyethylene) at 30°C for filtration to obtain a polymer E aqueous solution E-2. The results of GPC analysis and LC-MS analysis of the obtained polymer E aqueous solution E-2 showed that the Mw of polymer E was 13,000 and the Mn was 10,000, and the content of dimers and trimers was less than 1 mass ppm relative to polymer E. The concentration of the obtained polymer E aqueous solution E-2 was 3.5 mass %. The content of low molecular weight bodies having a molecular weight of 700 to 3000 was less than 0.05% relative to the fluorinated polymer. In addition, the content of low molecular weight bodies having a molecular weight of 400 to 3000 was less than 0.05% relative to the fluorinated polymer.

Claims

1. A composition, characterized in that It contains water and a fluorine-containing polymer, wherein the fluorine-containing polymer is a polymer containing a structural unit M3 derived from a monomer represented by the general formula (1), CX2=CY(-CZ2-O-Rf-A) (1) In the formula, X is the same or different and is -H or -F, Y is -H, -F, alkyl or fluorinated alkyl, Z is the same or different and is -H, -F, alkyl or fluorinated alkyl; Rf is a fluorinated alkylene group having 1 to 40 carbon atoms, or a fluorinated alkylene group having 2 to 100 carbon atoms and having an ether bond; A is -COOM, -SO3M, -OSO3M or -C(CF3)2OM, M is -H, a metal atom, -NR 7 4. an imidazolium which may be substituted, a pyridinium which may be substituted, or a phosphonium which may be substituted, R 7 is H or an organic group; wherein at least one of X, Y and Z contains a fluorine atom, The fluorine-containing polymer is a water-soluble polymer in which the hydrogen atoms bonded to the carbon atoms are replaced by fluorine atoms at a ratio of 50% or more. The content of the structural unit M3 in the fluorinated polymer is 60 mol% or more relative to all polymerized units, In the composition, the content of the compound having a molecular weight of 700 to 3000 is 3.5% or less based on the fluorine-containing polymer.

2. The composition according to claim 1, wherein The content of the compound having a molecular weight of 400 to 3000 is 3.7% or less based on the fluorine-containing polymer.

3. The composition according to claim 1, wherein The content of the compound having a molecular weight of 700 or more and less than 10,000 is 5.0% or less based on the fluorine-containing polymer.

4. The composition according to any one of claims 1 to 3, wherein In the general formula (1), at least one of X is -H.

5. The composition according to any one of claims 1 to 3, wherein In the general formula (1), two Xs are -H.

6. The composition according to any one of claims 1 to 3, wherein In the general formula (1), Rf is a fluorinated alkylene group having 1 to 10 carbon atoms or a fluorinated alkylene group having 2 to 12 carbon atoms and having an ether bond.

7. The composition according to any one of claims 1 to 3, wherein The structural unit M3 is a structural unit (1A) based on a monomer represented by the following general formula (1A), CH2=CF(-CF2-O-Rf-A)(1A) Wherein, Rf and A are the same as above.

8. The composition according to any one of claims 1 to 3, wherein The structural unit M3 is a structural unit (1a) based on a fluoroallyl ether compound represented by the following general formula (1a), CX2=CFCF2-O-(CF(CF3)CF2O) n5 -CF(CF3)-A(1a) In the formula, each X is the same and represents F or H; n5 represents 0 or an integer of 1 to 10, and A has the same meaning as defined above.

9. The composition according to any one of claims 1 to 3, wherein A is -COOM.

10. The composition according to any one of claims 1 to 3, wherein M is -H, -Na, -K, -Li or -NH4.

11. The composition according to any one of claims 1 to 3, wherein The fluorine-containing polymer is a polymer in which the structural unit M3 accounts for 60 to 100 mol% of all polymerized units and the structural unit N3 derived from a monomer copolymerizable with the monomer represented by the general formula (1) accounts for 0 to 40 mol% of all polymerized units.

12. The composition according to any one of claims 1 to 3, wherein The fluorine-containing polymer has a number average molecular weight of 0.5×10 4 ~75.0×10 4 of polymers.

13. The composition according to any one of claims 1 to 3, wherein The fluorine-containing polymer includes an ionic group and has an ion exchange rate of 53 or less.

14. The composition according to any one of claims 1 to 3, wherein The composition comprises water and a fluorine-containing polymer, wherein the fluorine-containing polymer is a polymer comprising a structural unit M3 derived from a monomer represented by the general formula (1A), CH2=CF(-CF2-O-Rf-A) (1A) In the formula, Rf is a fluorinated alkylene group having 1 to 10 carbon atoms or a fluorinated alkylene group having 2 to 12 carbon atoms and having an ether bond; A is -COOM, M is -H, -Na, -K, -Li or -NH4, The fluorine-containing polymer is a water-soluble polymer in which the hydrogen atoms bonded to the carbon atoms are replaced by fluorine atoms at a ratio of 50% or more. The content of the structural unit M3 in the fluorinated polymer is 90 mol% or more relative to all polymerized units, The fluorine-containing polymer has a number average molecular weight of 1.0×10 4 ~30.0×10 4 The polymer In the composition, the content of the compound having a molecular weight of 700 to 3000 is 0.01% to 1.0% based on the fluorine-containing polymer.

15. A composition, characterized in that It contains water and a fluorine-containing polymer, wherein the fluorine-containing polymer is a polymer containing a structural unit M3 derived from a monomer represented by the general formula (1), CX2=CY(-CZ2-O-Rf-A) (1) In the formula, X is the same or different and is -H or -F, Y is -H, -F, alkyl or fluorinated alkyl, Z is the same or different and is -H, -F, alkyl or fluorinated alkyl; Rf is a fluorinated alkylene group having 1 to 40 carbon atoms, or a fluorinated alkylene group having 2 to 100 carbon atoms and having an ether bond; A is -COOM, -SO3M, -OSO3M or -C(CF3)2OM, M is -H, a metal atom, -NR 7 4. an imidazolium which may be substituted, a pyridinium which may be substituted, or a phosphonium which may be substituted, R 7 is H or an organic group; wherein at least one of X, Y and Z contains a fluorine atom, The fluorine-containing polymer is a water-soluble polymer in which the hydrogen atoms bonded to the carbon atoms are replaced by fluorine atoms at a ratio of 50% or more. The content of the structural unit M3 in the fluorinated polymer is 60 mol% or more relative to all polymerized units, The content of dimers and trimers of monomers forming structural units constituting the fluorinated polymer is 2.0% or less based on the fluorinated polymer.

16. The composition of claim 15, wherein The fluorine-containing polymer is a polymer containing an ionic group and having an ion exchange rate of 53 or less.

17. The composition according to claim 15 or 16, wherein The composition comprises water and a fluorine-containing polymer, wherein the fluorine-containing polymer is a polymer comprising a structural unit M3 derived from a monomer represented by the general formula (1A), CH2=CF(-CF2-O-Rf-A)(1A) In the formula, Rf is a fluorinated alkylene group having 1 to 10 carbon atoms or a fluorinated alkylene group having 2 to 12 carbon atoms and having an ether bond; A is -COOM, M is -H, -Na, -K, -Li or -NH4, The fluorine-containing polymer is a water-soluble polymer in which the hydrogen atoms bonded to the carbon atoms are replaced by fluorine atoms at a ratio of 50% or more. The content of the structural unit M3 in the fluorinated polymer is 90 mol% or more relative to all polymerized units, The fluorine-containing polymer has a number average molecular weight of 1.0×10 4 ~30.0×10 4 The polymer The content of dimers and trimers of monomers forming structural units constituting the fluorinated polymer is 1.0% or less based on the fluorinated polymer.

18. The composition according to any one of claims 1 to 3, 15 and 16, which is a coating agent.

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