Production method of fluoropolymer aqueous dispersion

Abstract

To provide a method for producing an aqueous dispersion containing a fluoropolymer in a high concentration.SOLUTION: Provided is a method for producing a fluoropolymer aqueous dispersion, the method including concentrating a composition comprising a polymer (I) containing a polymerization unit (I) derived from a monomer (I) represented by the general formula (I), a fluoropolymer (excluding the polymer (I)), a nonionic surfactant, a fluorine-free anionic surfactant, and an aqueous medium, thereby obtaining an aqueous dispersion containing the fluoropolymer. CX1X3=CX2R(-CZ1Z2-A0)m (I) (where X1 and X3 are each independently F, Cl, H, or CF3; X2 is H, F, an alkyl group, or a fluorine-containing alkyl group; A0 is an anionic group; R is a linking group; Z1 and Z2 are each independently H, F, an alkyl group, or a fluorine-containing alkyl group; and m is an integer of 1 or more).SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to a method for producing an aqueous dispersion of a fluoropolymer.

Background Art

[0002] Patent Document 1 discloses that a dispersion of a fluorinated polymer has the following general formula: Y’-(P 1 ) n -CH(Y)-(P 2 ) n’ -Y” (1) (wherein: Y, Y’ and Y” are anionic or nonionic groups, provided that at least one of Y, Y’ or Y” is an anionic group and at least one of the remaining Y, Y’ or Y” is a nonionic group; P 1 and P 2 are the same or different and are linear or branched alkylene groups having 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms, which may optionally have one or more unsaturations; n and n’ are the same or different and are 0 or 1) containing one or more anionic surfactants having a high flocculation stability combined with a high shear stress stability, and a method for producing a dispersion of a fluorinated polymer substantially free of a fluorinated surfactant, particularly a fluorinated ionic surfactant, comprising the following steps: - obtaining an aqueous dispersion of a fluoropolymer by polymerization, - optionally concentrating to increase the amount of the fluoropolymer, - substantially reducing the amount of an ionic fluorinated surfactant, - adding a surfactant of formula (1), - homogenizing the dispersion is described.

[0003] Patent Document 2 describes a method for producing a fluoropolymer, which includes a step of obtaining a fluoropolymer by polymerizing a fluoromonomer in an aqueous medium in the presence of a polymer (1) containing a polymerized unit (1) based on a monomer represented by the following general formula (1). CX 2 =CY(-CZ 2 -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; Z is the same or different and is -H, -F, an alkyl group or a fluoroalkyl group. Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms or a fluorine-containing alkylene group having an ether bond and having 2 to 100 carbon atoms. A is -COOM, -SO 3 M or -OSO 3 M (M is -H, a metal atom, -NR 7 4 , imidazolium which may have a substituent, pyridinium which may have a substituent or phosphonium which may have a substituent, and R 7 is H or an organic group. However, at least one of X, Y and Z contains a fluorine atom.)

[0004] Patent Document 3 describes a method for producing an aqueous dispersion of a fluoropolymer, which includes a step A of subjecting an aqueous dispersion before treatment, which contains a fluoropolymer (excluding the polymer (I)) obtained by polymerization in the presence of a polymer (I) containing a polymerized unit (I) represented by the following general formula (I), to ultrafiltration, microfiltration or dialysis membrane treatment, or a combination thereof. CX 1 X 3 =CX 2 R(-CZ 1 Z 2 -A 0 ) m (I) (In the formula, X 1 and X 3 are each independently F, Cl, H or CF 3 ; X 2 is H, F, an alkyl group or a fluorine-containing alkyl group; A0 is an anionic group; R is a linking group; Z 1 and Z 2 are each independently H, F, an alkyl group or a fluorinated alkyl group; m is an integer of 1 or more.)

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the present disclosure, it is an object to provide a method for producing an aqueous dispersion of a fluoropolymer that can rapidly increase the concentration of the fluoropolymer in a composition containing a fluoropolymer, a specific polymer, and an aqueous medium, and finally obtain an aqueous dispersion containing the fluoropolymer at a high concentration, and further can rapidly remove the specific polymer from the composition.

Means for Solving the Problems

[0007] According to the present disclosure, there is provided a method for producing an aqueous dispersion of a fluoropolymer, which comprises concentrating a composition containing a polymer (I) containing a polymerization unit (I) based on a monomer (I) represented by the general formula (I), a fluoropolymer (excluding the polymer (I)), a nonionic surfactant, a fluorine-free anionic surfactant, and an aqueous medium to obtain an aqueous dispersion containing the fluoropolymer. CX 1 X 3 =CX 2 R(-CZ 1 Z 2 -A 0 )m (I) (wherein X 1 and X 3 are each independently F, Cl, H or CF 3 ; X 2 is H, F, an alkyl group or a fluorinated alkyl group; A 0 is an anionic group; R is a linking group; Z 1 and Z 2 are each independently H, F, an alkyl group or a fluorinated alkyl group; m is an integer of 1 or more.)

[0008] In the production method of the present disclosure, the content of the fluorine-free anionic surfactant in the composition is preferably 10 to 10,000 mass ppm with respect to the fluoropolymer. In the production method of the present disclosure, the surface tension measured at 25 °C for an aqueous solution containing 0.1 mass% of the fluorine-free anionic surfactant is preferably 60 mN / m or less. In the production method of the present disclosure, the content of the nonionic surfactant in the composition is preferably 1.0 to 40 mass% with respect to the fluoropolymer. In the production method of the present disclosure, the nonionic surfactant is preferably at least one selected from the group consisting of a nonionic surfactant represented by the general formula (i) and a nonionic surfactant represented by the general formula (ii). R 6 -O-A 1 -H (i) (wherein R 6 is a linear or branched primary or secondary alkyl group having 8 to 18 carbon atoms, and A 1 is a polyoxyalkylene chain.) R 7 -C 6 H 4 -O-A 2 -H (ii) (wherein R 7 is a linear or branched alkyl group having 4 to 12 carbon atoms, and A 2It is a polyoxyethylene chain composed of an average repeating number of oxyethylene groups of 5 to 20.) In the production method of the present disclosure, it is preferable that the pH of the composition is 4.0 to 11.5.) In the production method of the present disclosure, it is preferable that the fluoropolymer is polytetrafluoroethylene.) In the production method of the present disclosure, it is preferable that the content of the fluoropolymer in the aqueous dispersion is 50% by mass or more with respect to the aqueous dispersion.) In the production method of the present disclosure, in the presence of polymer (I), by polymerizing a fluoromonomer in an aqueous medium, after obtaining a polymerization dispersion liquid containing the fluoropolymer, polymer (I) and the aqueous medium, it is preferable to obtain the composition by mixing the polymerization dispersion liquid, the nonionic surfactant and the fluorine-free anionic surfactant.) In the production method of the present disclosure, it is preferable to polymerize the fluoromonomer substantially in the absence of a fluorine-containing surfactant.) In the production method of the present disclosure, it is preferable to subject the polymerization dispersion liquid and the composition to the concentration without contacting either an anion exchange resin or a cation exchange resin.)

[0009] According to the present disclosure, there is provided an aqueous fluoropolymer dispersion liquid containing a polymer (I) containing a polymerization unit (I) based on a monomer (I) represented by the general formula (I), a fluoropolymer (excluding polymer (I)), a nonionic surfactant, and an aqueous medium, wherein the content of polymer (I) is 500 ppm by mass or less with respect to the aqueous fluoropolymer dispersion liquid, and the content of the fluoropolymer is 50% by mass or more and 70% by mass or less with respect to the aqueous fluoropolymer dispersion liquid.) CX 1 X 3 =CX 2 R(-CZ 1 Z 2 -A 0 ) m (I) (In the formula, X 1 and X3 is, independently of each other, F, Cl, H or CF 3 ; X 2 is H, F, an alkyl group or a fluorinated alkyl group; A 0 is an anionic group; R is a linking group; Z 1 and Z 2 are, independently of each other, H, F, an alkyl group or a fluorinated alkyl group; m is an integer of 1 or more.)

[0010] The aqueous dispersion of the fluoropolymer of the present disclosure preferably has a viscosity at 25 °C of 5.0 mPa·s or more and 300 mPa·s or less. In the aqueous dispersion of the fluoropolymer of the present disclosure, the content of the nonionic surfactant is preferably 4.0% by mass or more and 12% by mass or less with respect to the fluoropolymer. The aqueous dispersion of the fluoropolymer of the present disclosure preferably contains substantially no fluorinated surfactant.

[0011] According to the present disclosure, there is provided an aqueous dispersion of a fluoropolymer containing a fluoropolymer, a nonionic surfactant, and an aqueous medium, which contains substantially no fluorinated surfactant, has a viscosity at 25 °C of 100 mPa·s or less, and the color tone of the impregnated fiber obtained by impregnating the glass fiber with the aqueous dispersion of the fluoropolymer and firing at 380 °C is L * in the CIELAB color scale is 74.0 or more, or a * in the CIELAB color scale is 1.0 or less, the content of the fluoropolymer is 50% by mass or more and 70% by mass or less with respect to the aqueous dispersion of the fluoropolymer, and the content of the nonionic surfactant is 4.0% by mass or more and 12% by mass or less with respect to the fluoropolymer.

[0012] In the aqueous dispersion of the fluoropolymer of the present disclosure, the fluorinated surfactant is preferably an anionic fluorinated surfactant having a molecular weight of the anionic moiety of 800 or less. In the aqueous dispersion of the fluoropolymer of the present disclosure, the content of the fluorosurfactant is preferably 100 mass ppb or less. In the aqueous dispersion of the fluoropolymer of the present disclosure, the fluorosurfactant is F(CF 2 ) 7 COOM, F(CF 2 ) 5 COOM, H(CF 2 ) 6 COOM, H(CF 2 ) 7 COOM, CF 3 O(CF 2 ) 3 OCHFCF 2 COOM, C 3 F 7 OCF(CF 3 )CF 2 OCF(CF 3 )COOM, CF 3 CF 2 CF 2 OCF(CF 3 )COOM, CF 3 CF 2 OCF 2 CF 2 OCF 2 COOM, C 2 F 5 OCF(CF 3 )CF 2 OCF(CF 3 )COOM, CF 3 OCF(CF 3 )CF 2 OCF(CF 3 )COOM, CF 2 ClCF 2 CF 2 OCF(CF 3 )CF 2 OCF 2 COOM, CF2 ClCF 2 CF 2 OCF 2 CF(CF 3 )OCF 2 COOM、 CF 2 ClCF(CF 3 )OCF(CF 3 )CF 2 OCF 2 COOM、 CF 2 ClCF(CF 3 )OCF 2 CF(CF 3 )OCF 2 COOM、および

Chemical formula

Advantages of the Invention

[0013] According to the present disclosure, it is possible to rapidly increase the concentration of the fluoropolymer in the composition containing the fluoropolymer, a specific polymer, and an aqueous medium, and finally obtain an aqueous dispersion containing the fluoropolymer at a high concentration. Furthermore, it is possible to provide a method for producing an aqueous dispersion of a fluoropolymer capable of rapidly removing a specific polymer from the composition.

Modes for Carrying Out the Invention

[0014] Before specifically describing the present disclosure, some terms used in the present disclosure will be defined or explained.

[0015] In the present disclosure, a fluororesin is a semi-crystalline fluoropolymer and is a fluoroplastic. The fluororesin has a melting point and has thermoplasticity, and may be melt processable or non-melt processable.

[0016] In the present disclosure, melt processability means that it is possible to melt and process a polymer using conventional processing equipment such as an extruder and an injection molding machine. Therefore, a melt-processable fluororesin usually has a melt flow rate measured by the measurement method described below of 0.01 to 500 g / 10 min.

[0017] In the present disclosure, a fluororubber is an amorphous fluoropolymer. "Amorphous" means that the magnitude of the melting peak (ΔH) appearing in the differential scanning calorimetry [DSC] (heating rate 10 °C / min) or differential thermal analysis [DTA] (heating rate 10 °C / min) of the fluoropolymer is 4.5 J / g or less. The fluororubber exhibits elastomer properties by crosslinking. Elastomer properties mean the property that a polymer can be stretched and can retain its original length when the force required to stretch the polymer is no longer applied.

[0018] In the present disclosure, a partially fluorinated rubber is a fluoropolymer containing fluoromonomer units and having a content of perfluoromonomer units of less than 90 mol% based on all polymerization units, having a glass transition temperature of 20 °C or lower, and having a melting peak (ΔH) magnitude of 4.5 J / g or less.

[0019] In the present disclosure, a perfluoropolymer (perfluoroelastomer) is a fluoropolymer having a content of perfluoromonomer units of 90 mol% or more, preferably 91 mol% or more, based on all polymerization units, having a glass transition temperature of 20°C or lower, and having a melting peak (ΔH) size of 4.5 J / g or less. Further, it is a polymer in which the concentration of fluorine atoms contained in the fluoropolymer is 71 mass% or more, preferably 71.5 mass% or more. In the present disclosure, the concentration of fluorine atoms contained in the fluoropolymer is determined by calculation of the concentration (mass%) of fluorine atoms contained in the fluoropolymer from the types and contents of the respective monomers constituting the fluoropolymer.

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

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

[0022] In the present disclosure, polytetrafluoroethylene [PTFE] is preferably a fluoropolymer having a content of tetrafluoroethylene units of 99 mol% or more based on all polymerization units.

[0023] In the present disclosure, a fluororesin (excluding polytetrafluoroethylene) and a fluororubber are both preferably fluoropolymers having a content of tetrafluoroethylene units of less than 99 mol% based on all polymerization units.

[0024] In the present disclosure, the content of each monomer constituting the fluoropolymer can be calculated by appropriately combining NMR, FT-IR, elemental analysis, and X-ray fluorescence analysis according to the type of monomer.

[0025] In the present disclosure, the "organic group" means a group containing one or more carbon atoms, or a group formed by removing one hydrogen atom from an organic compound. Examples of the "organic group" include an alkyl group which may have one or more substituents, an alkenyl group which may have one or more substituents, an alkynyl group which may have one or more substituents, a cycloalkyl group which may have one or more substituents, a cycloalkenyl group which may have one or more substituents, a cycloalkadienyl group which may have one or more substituents, an aryl group which may have one or more substituents, an aralkyl group which may have one or more substituents, a non-aromatic heterocyclic group which may have one or more substituents, a heteroaryl group which may have one or more substituents, a cyano group, a formyl group, RaO-, RaCO-, RaSO 2 -, RaCOO-, RaNRaCO-, RaCONRa-, RaOCO-, RaOSO 2 -, and, RaNRbSO 2 - (In these formulas, Ra is independently an alkyl group which may have one or more substituents, an alkenyl group which may have one or more substituents, An alkynyl group which may have one or more substituents, A cycloalkyl group which may have one or more substituents, A cycloalkenyl group which may have one or more substituents, A cycloalkadienyl group which may have one or more substituents, An aryl group which may have one or more substituents, An aralkyl group which may have one or more substituents, A non-aromatic heterocyclic group which may have one or more substituents, or A heteroaryl group which may have one or more substituents, Rb is independently H or an alkyl group which may have one or more substituents) is included. As the above organic group, an alkyl group which may have one or more substituents is preferable.

[0026] Also, in the present disclosure, the "substituent" means a group that can be substituted. Examples of the "substituent" include an aliphatic group, an aromatic group, a heterocyclic group, an acyl group, an acyloxy group, an acylamino group, an aliphatic oxy group, an aromatic oxy group, a heterocyclic oxy group, an aliphatic oxycarbonyl group, an aromatic oxycarbonyl group, a heterocyclic oxycarbonyl group, a carbamoyl group, an aliphatic sulfonyl group, an aromatic sulfonyl group, a heterocyclic sulfonyl group, an aliphatic sulfonyloxy group, an aromatic sulfonyloxy group, a heterocyclic sulfonyloxy group, a sulfamoyl group, an aliphatic sulfonamide group, an aromatic sulfonamide group, a heterocyclic sulfonamide group, an amino group, an aliphatic amino group, an aromatic amino group, a heterocyclic amino group, an aliphatic oxycarbonylamino group, an aromatic oxycarbonylamino group, a heterocyclic oxycarbonylamino group, an aliphatic sulfinyl group, an aromatic sulfinyl group, an aliphatic thio group, an aromatic thio group, a hydroxy group, a cyano group, a sulfo group, a carboxy group, an aliphatic oxyamino group, an aromatic oxyamino group, a carbamoylamino group, a sulfamoylamino group, a halogen atom, a sulfamoylcarbamoyl group, a carbamoylsulfamoyl group, a di-aliphatic oxyphosphinyl group, and a di-aromatic oxyphosphinyl group.

[0027] The above aliphatic group may be saturated or unsaturated, and may also have a hydroxy group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the above aliphatic group include an alkyl group having 1 to 8, preferably 1 to 4 carbon atoms in total, such as a methyl group, an ethyl group, a vinyl group, a cyclohexyl group, a carbamoylmethyl group, etc.

[0028] The above aromatic group may have, for example, a nitro group, a halogen atom, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the above aromatic group include an aryl group having 6 to 12, preferably 6 to 10 carbon atoms in total, such as a phenyl group, a 4-nitrophenyl group, a 4-acetylaminophenyl group, a 4-methanesulfonylphenyl group, etc.

[0029] The above heterocyclic group may have a halogen atom, a hydroxy group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the above heterocyclic group include a 5- to 6-membered heterocycle having 2 to 12, preferably 2 to 10 carbon atoms in total, such as a 2-tetrahydrofuryl group, a 2-pyrimidyl group, etc.

[0030] The above acyl group may have an aliphatic carbonyl group, an arylcarbonyl group, a heterocyclic carbonyl group, a hydroxy group, a halogen atom, an aromatic group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the above acyl group include an acyl group having 2 to 8, preferably 2 to 4 carbon atoms in total, such as an acetyl group, a propanoyl group, a benzoyl group, a 3-pyridinecarbonyl group, etc.

[0031] The acylamino group may have an aliphatic group, an aromatic group, a heterocyclic group, etc. For example, it may have an acetylamino group, a benzoylamino group, a 2-pyridinecarbonylamino group, a propanoylamino group, etc. Examples of the acylamino group include an acylamino group having 2 to 12 total carbon atoms, preferably 2 to 8 total carbon atoms, an alkylcarbonylamino group having 2 to 8 total carbon atoms, such as an acetylamino group, a benzoylamino group, a 2-pyridinecarbonylamino group, a propanoylamino group, etc.

[0032] The aliphatic oxycarbonyl group may be saturated or unsaturated, and may also have a hydroxy group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the aliphatic oxycarbonyl group include an alkoxycarbonyl group having 2 to 8 total carbon atoms, preferably 2 to 4 total carbon atoms, such as a methoxycarbonyl group, an ethoxycarbonyl group, a (t)-butoxycarbonyl group, etc.

[0033] The carbamoyl group may have an aliphatic group, an aromatic group, a heterocyclic group, etc. Examples of the carbamoyl group include an unsubstituted carbamoyl group, an alkylcarbamoyl group having 2 to 9 total carbon atoms, preferably an unsubstituted carbamoyl group, an alkylcarbamoyl group having 2 to 5 total carbon atoms, such as an N-methylcarbamoyl group, an N,N-dimethylcarbamoyl group, an N-phenylcarbamoyl group, etc.

[0034] The aliphatic sulfonyl group may be saturated or unsaturated, and may also have a hydroxy group, an aromatic group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the aliphatic sulfonyl group include an alkylsulfonyl group having 1 to 6 total carbon atoms, preferably 1 to 4 total carbon atoms, such as a methanesulfonyl group, etc.

[0035] The above aromatic sulfonyl group may have a hydroxy group, an aliphatic group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the above aromatic sulfonyl group include arylsulfonyl groups having 6 to 10 carbon atoms in total, such as a benzenesulfonyl group.

[0036] The above amino group may have an aliphatic group, an aromatic group, a heterocyclic group, etc.

[0037] The above acylamino group may have, for example, an acetylamino group, a benzoylamino group, a 2-pyridinecarbonylamino group, a propanoylamino group, etc. Examples of the above acylamino group include acylamino groups having 2 to 12 carbon atoms in total, preferably acylamino groups having 2 to 8 carbon atoms in total, more preferably alkylcarbonylamino groups having 2 to 8 carbon atoms in total, such as an acetylamino group, a benzoylamino group, a 2-pyridinecarbonylamino group, a propanoylamino group, etc.

[0038] The above aliphatic sulfonamide group, aromatic sulfonamide group, heterocyclic sulfonamide group may be, for example, a methanesulfonamide group, a benzenesulfonamide group, a 2-pyridinesulfonamide group, etc.

[0039] The above sulfamoyl group may have an aliphatic group, an aromatic group, a heterocyclic group, etc. Examples of the above sulfamoyl group include a sulfamoyl group, an alkylsulfamoyl group having 1 to 9 carbon atoms in total, a dialkylsulfamoyl group having 2 to 10 carbon atoms in total, an arylsulfamoyl group having 7 to 13 carbon atoms in total, a heterocyclic sulfamoyl group having 2 to 12 carbon atoms in total, more preferably a sulfamoyl group, an alkylsulfamoyl group having 1 to 7 carbon atoms in total, a dialkylsulfamoyl group having 3 to 6 carbon atoms in total, an arylsulfamoyl group having 6 to 11 carbon atoms in total, a heterocyclic sulfamoyl group having 2 to 10 carbon atoms in total. For example, a sulfamoyl group, a methylsulfamoyl group, an N,N-dimethylsulfamoyl group, a phenylsulfamoyl group, a 4-pyridinesulfamoyl group, etc. may be mentioned.

[0040] The above aliphatic oxy group may be saturated or unsaturated, and may have a methoxy group, an ethoxy group, an i-propyloxy group, a cyclohexyloxy group, a methoxyethoxy group, etc. Examples of the above aliphatic oxy group include an alkoxy group having 1 to 8, preferably 1 to 6 carbon atoms in total, such as a methoxy group, an ethoxy group, an i-propyloxy group, a cyclohexyloxy group, a methoxyethoxy group, etc.

[0041] The above aromatic amino group and heterocyclic amino group may have an aliphatic group, an aliphatic oxy group, a halogen atom, a carbamoyl group, a heterocyclic group condensed with the aryl group, an aliphatic oxycarbonyl group, preferably an aliphatic group having 1 to 4 carbon atoms in total, an aliphatic oxy group having 1 to 4 carbon atoms in total, a halogen atom, a carbamoyl group having 1 to 4 carbon atoms in total, a nitro group, an aliphatic oxycarbonyl group having 2 to 4 carbon atoms in total.

[0042] The above aliphatic thio group may be saturated or unsaturated, and examples thereof include an alkylthio group having 1 to 8, more preferably 1 to 6 carbon atoms in total, such as a methylthio group, an ethylthio group, a carbamoylmethylthio group, a t-butylthio group, etc.

[0043] The above carbamoyl amino group may have an aliphatic group, an aryl group, a heterocyclic group, etc. Examples of the above carbamoyl amino group include a carbamoyl amino group, an alkylcarbamoyl amino group having 2 to 9 carbon atoms in total, a dialkylcarbamoyl amino group having 3 to 10 carbon atoms in total, an arylcarbamoyl amino group having 7 to 13 carbon atoms in total, a heterocyclic carbamoyl amino group having 3 to 12 carbon atoms in total, preferably a carbamoyl amino group, an alkylcarbamoyl amino group having 2 to 7 carbon atoms in total, a dialkylcarbamoyl amino group having 3 to 6 carbon atoms in total, an arylcarbamoyl amino group having 7 to 11 carbon atoms in total, a heterocyclic carbamoyl amino group having 3 to 10 carbon atoms in total. For example, a carbamoyl amino group, a methylcarbamoyl amino group, an N,N-dimethylcarbamoyl amino group, a phenylcarbamoyl amino group, a 4-pyridinecarbamoyl amino group, etc. can be mentioned.

[0044] In the present disclosure, a range represented by endpoints includes all numerical values included within that range (for example, 1 to 10 includes 1.4, 1.9, 2.33, 5.75, 9.98, etc.).

[0045] In the present disclosure, the description of "at least 1" includes all numerical values of 1 or more (for example, at least 2, at least 4, at least 6, at least 8, at least 10, at least 25, at least 50, at least 100, etc.).

[0046] Hereinafter, specific embodiments of the present disclosure will be described in detail, but the present disclosure is not limited to the following embodiments.

[0047] In the production method of the present disclosure, by concentrating a composition containing a fluoropolymer, a polymer (I) containing a polymerization unit (I) based on the monomer (I) represented by the general formula (I), a nonionic surfactant, a fluorine-free anionic surfactant, and an aqueous medium, an aqueous dispersion containing a fluoropolymer is obtained. CX 1 X 3 =CX 2 R(-CZ 1 Z2 -A 0 ) m (I) (wherein X 1 and X 3 are each independently F, Cl, H or CF 3 ; X 2 is H, F, an alkyl group or a fluorinated alkyl group; A 0 is an anionic group; R is a linking group; Z 1 and Z 2 are each independently H, F, an alkyl group or a fluorinated alkyl group; m is an integer of 1 or more)

[0048] Patent Documents 2 and 3 describe the polymerization of fluoromonomers in an aqueous medium in the presence of a specific polymer having an anionic group, and the composition obtained by the polymerization contains a specific polymer, a fluoropolymer and an aqueous medium.

[0049] In order to apply such a composition to various uses and fully exhibit the excellent properties of the fluoropolymer, it is preferable that the concentration of the fluoropolymer in the composition is high and the content of the specific polymer is low. Further, it is advantageous in terms of handleability that the fluoropolymer in the composition is stably dispersed in the aqueous medium without sedimentation.

[0050] The production method of the present disclosure not only solves these problems, but also can increase the concentration of the fluoropolymer in the composition in a short time and remove the specific polymer in a short time.

[0051] That is, in the production method of the present disclosure, in a state where a nonionic surfactant and a fluorine-free anionic surfactant are present in the composition, by concentrating a composition containing a polymer (I), a fluoropolymer, and an aqueous medium, an aqueous dispersion of a fluoropolymer is obtained. Therefore, an aqueous dispersion with a high concentration of a fluoropolymer can be obtained, and the content of the polymer (I) in the aqueous dispersion is surprisingly reduced. Further, the obtained aqueous dispersion of a fluoropolymer is excellent in sedimentation stability and mechanical stability. Furthermore, according to the production method of the present disclosure, the concentration of the fluoropolymer can be rapidly increased, and finally, an aqueous dispersion containing the fluoropolymer at a high concentration can be obtained. Moreover, since a specific polymer can be rapidly removed from the composition, an aqueous dispersion of a high-concentration fluoropolymer can be produced with high productivity.

[0052] (fluorine-free anionic surfactant) In the production method of the present disclosure, a fluorine-free anionic surfactant is used during concentration. By performing concentration in the presence of a fluorine-free anionic surfactant, the rate at which the concentration of the fluoropolymer in the composition increases becomes high, and the rate at which the polymer (I) in the composition is removed also becomes high. Furthermore, compared with the case where concentration is performed in the absence of a fluorine-free anionic surfactant, the concentration of the fluoropolymer in the finally obtained aqueous dispersion of a fluoropolymer becomes high, and the sedimentation stability and mechanical stability of the obtained aqueous dispersion of a fluoropolymer are improved. The higher the solid content concentration of the concentrated phase after concentration, the more options (dosage, type) of compounding agents there are.

[0053] The fluorine-free anionic surfactant used in the production method of the present disclosure usually has a hydrophilic part such as a carboxylate, a sulfonate, or a sulfate, and a hydrophobic part that is a long-chain hydrocarbon part such as an alkyl.

[0054] Examples of the fluorine-free anionic surfactant include compounds having a surface tension of 0.1% by mass aqueous solution of, for example, 60 mN / m or less, preferably 50 mN / m or less. The surface tension can be measured by the Wilhelmy method at 25°C.

[0055] Examples of the fluorine-free anionic surfactant include alkyl sulfates such as lauryl sulfate, alkyl aryl sulfonic acids such as dodecylbenzene sulfonic acid, alkyl esters of sulfosuccinic acid, and salts thereof. The above fluorine-free anionic surfactant may be a combination of one or more of these compounds.

[0056] The alkyl ester of sulfosuccinic acid and its salt may be a monoester, but is preferably a diester.

[0057] Examples of the alkyl ester of sulfosuccinic acid and its salt include, for example, the general formula: R 21 -OCOCH(SO 3 A 21 )CH 2 COO-R 22 (In the formula, R 21 and R 22 represent the same or different alkyl groups having 4 to 12 carbon atoms, and A 21 represents an alkali metal, an alkaline earth metal, or NH 4 .). Examples thereof include alkyl esters of sulfosuccinic acid and salts thereof represented by the formula.

[0058] Examples of R 21 and R 22 include linear or branched alkyl groups such as n-butyl, iso-butyl, sec-butyl, n-pentyl, iso-pentyl, neopentyl, tert-pentyl, n-hexyl, iso-hexyl, tert-hexyl, n-heptyl, iso-heptyl, tert-heptyl, n-octyl, iso-octyl, tert-octyl, n-nonyl, iso-nonyl, tert-nonyl, n-decyl, 2-ethylhexyl, etc.

[0059] As for 21 , Na, NH 4 etc. are preferable. Examples of the alkyl sulfosuccinate include di-n-octyl sulfosuccinate, di-2-ethylhexyl sulfosuccinate, and the like.

[0060] The fluorine-free anionic surfactant may have an acid group. As the acid group, those selected from the group consisting of a carboxyl group, a sulfate group, a sulfonic acid group, a phosphate group, and their salts are preferable, and among them, those selected from the group consisting of a carboxyl group, a sulfate group, a sulfonic acid group, and their salts are preferable.

[0061] In addition to the above acid group, the fluorine-free anionic surfactant may further have other groups such as a polyoxyalkylene group having an oxyalkylene group with 2 to 4 carbon atoms, an amino group, etc. The above amino group is not protonated.

[0062] As the fluorine-free anionic surfactant, an anionic hydrocarbon surfactant having a hydrocarbon as the main chain is preferable. Examples of the hydrocarbon include those having a saturated or unsaturated aliphatic chain with 6 to 40 carbon atoms, preferably 8 to 20 carbon atoms. The above saturated or unsaturated aliphatic chain may be either a straight chain or a branched chain, and may have a cyclic structure. The above hydrocarbon may be aromatic or may have an aromatic group. The above hydrocarbon may have a heteroatom such as oxygen, nitrogen, sulfur, etc.

[0063] Examples of the fluorine-free anionic surfactant include alkyl sulfonic acids such as lauryl sulfonic acid and their salts; alkyl aryl sulfates and their salts; aliphatic (carboxylic) acids such as lauric acid and their salts; alkyl phosphate esters, alkyl aryl phosphate esters or their salts; etc. Among them, those selected from the group consisting of sulfonic acids, carboxylic acids and their salts are preferred, and aliphatic carboxylic acids or their salts are preferred. As the aliphatic carboxylic acid or its salt, for example, a saturated or unsaturated aliphatic carboxylic acid having 9 to 13 carbon atoms in which the terminal H may be substituted with -OH or its salt is preferred. As the aliphatic carboxylic acid, a monocarboxylic acid is preferred, and as the monocarboxylic acid, decanoic acid, undecanoic acid, undecenoic acid, lauric acid, hydroxydodecanoic acid are preferred.

[0064] As the fluorine-free anionic surfactant, at least one selected from the group consisting of alkyl sulfosuccinates and their salts, alkyl sulfates and their salts, and monocarboxylic acids and their salts is preferred, at least one selected from the group consisting of dioctyl sulfosuccinic acid, lauryl sulfate, decanoic acid and their salts is more preferred, and at least one selected from the group consisting of dioctyl sulfosuccinic acid, ammonium dioctyl sulfosuccinate, ammonium lauryl sulfate and ammonium decanoate is even more preferred.

[0065] The content of the fluorine-free anionic surfactant in the composition to be concentrated is preferably 10 to 10,000 mass ppm, more preferably 5,000 mass ppm or less, and even more preferably 1,000 mass ppm or less, based on the fluoropolymer. By adjusting the content of the fluorine-free anionic surfactant within the above range, the concentration of the fluoropolymer in the composition can be increased at a higher rate. If the content of the fluorine-free anionic surfactant is too high, the fluoropolymer is likely to be mixed into the supernatant phase formed by concentration, and the yield of the fluoropolymer may deteriorate.

[0066] The content of the fluorine-free anionic surfactant in the composition can be determined by calculation from the added amount of the fluorine-free anionic surfactant used in the preparation of the composition.

[0067] (Nonionic surfactant) The nonionic surfactant used in the production method of the present disclosure usually does not contain a charged group and has a hydrophobic part that is a long-chain hydrocarbon. The hydrophilic part of the nonionic surfactant contains a water-soluble functional group such as a chain of ethylene ether derived from the polymerization with ethylene oxide.

[0068] Examples of the nonionic surfactant include the following. Polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ester, sorbitan alkyl ester, polyoxyethylene sorbitan alkyl ester, glycerol ester, and derivatives thereof.

[0069] Specific examples of polyoxyethylene alkyl ether: polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene behenyl ether, etc.

[0070] Specific examples of polyoxyethylene alkyl phenyl ether: polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, etc.

[0071] Specific examples of polyoxyethylene alkyl ester: polyethylene glycol monolaurate, polyethylene glycol monooleate, polyethylene glycol monostearate, etc.

[0072] Specific examples of sorbitan alkyl ester: polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, etc.

[0073] Specific examples of polyoxyethylene sorbitan alkyl esters: polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, etc.

[0074] Specific examples of glycerol esters: glycerol monomyristate, glycerol monostearate, glycerol monooleate, etc.

[0075] Specific examples of the above derivatives: polyoxyethylene alkylamine, polyoxyethylene alkylphenyl-formaldehyde condensate, polyoxyethylene alkyl ether phosphate, etc.

[0076] The above ethers and esters may have an HLB value of 10 to 18.

[0077] Examples of nonionic surfactants include Triton (registered trademark) X series (X15, X45, X100, etc.), Tergitol (registered trademark) 15-S series, Tergitol (registered trademark) TMN series (TMN-6, TMN-10, TMN-100, etc.), Tergitol (registered trademark) L series manufactured by The Dow Chemical Company; Pluronic (registered trademark) R series (31R1, 17R2, 10R5, 25R4 (m~22, n~23)), Iconol (registered trademark) TDA series (TDA-6, TDA-9, TDA-10, etc.) manufactured by BASF.

[0078] As the nonionic surfactant, it is preferably a nonionic surfactant that does not contain fluorine. For example, ether-type nonionic surfactants such as polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ether, and polyoxyethylene alkylene alkyl ether; polyoxyethylene derivatives such as ethylene oxide / propylene oxide block copolymers; ester-type nonionic surfactants such as sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, glycerin fatty acid ester, and polyoxyethylene fatty acid ester; amine-based nonionic surfactants such as polyoxyethylene alkylamine and alkyl alkanolamide; and the like.

[0079] In the above nonionic surfactant, the hydrophobic group may be any of an alkylphenyl group, a linear alkyl group, and a branched alkyl group.

[0080] As the nonionic surfactant, a nonionic surfactant represented by the general formula (i) is preferable. R 6 -O-A 1 -H (i) (In the formula, R 6 is a linear or branched primary or secondary alkyl group having 8 to 18 carbon atoms, and A 1 is a polyoxyalkylene chain.)

[0081] In the general formula (i), the number of carbon atoms of R 6 is preferably 10 to 16, more preferably 12 to 16. When the number of carbon atoms of R 6 is 18 or less, excellent sedimentation stability of the composition is easily obtained. When the number of carbon atoms of R 6 exceeds 18, the pour point is high and it is difficult to handle. When the number of carbon atoms of R 6 is less than 8, the surface tension of the composition becomes high and the permeability and wettability are likely to decrease.

[0082] A 1The polyoxyalkylene chain may consist of oxyethylene and oxypropylene. It is a polyoxyalkylene chain composed of an average repeat number of 5 to 20 of oxyethylene groups and an average repeat number of 0 to 2 of oxypropylene groups, and it is a hydrophilic group. The number of oxyethylene units may include any of a normally provided broad or narrow unimodal distribution, or a broader or bimodal distribution obtained by blending. When the average repeat number of oxypropylene groups exceeds 0, the oxyethylene groups and oxypropylene groups in the polyoxyalkylene chain may be arranged in a block or random manner. From the viewpoints of the viscosity and sedimentation stability of the composition, a polyoxyalkylene chain composed of an average repeat number of 7 to 12 of oxyethylene groups and an average repeat number of 0 to 2 of oxypropylene groups is preferred. Especially when A 1 has an average of 0.5 to 1.5 oxypropylene groups, it has good low-foaming property and is preferred.

[0083] More preferably, R 6 is (R’)(R’’)HC-, where R’ and R’’ are the same or different linear, branched, or cyclic alkyl groups, and the total amount of carbon atoms is at least 5, preferably 7 to 17. Preferably, at least one of R’ or R’’ is a branched or cyclic hydrocarbon group.

[0084] Specific examples of the above polyoxyethylene alkyl ether include C 13 H 27 -O-(C 2 H 4 O) n -H, C 12 H 25 -O-(C 2 H 4 O) n -H, C 10 H 21 CH(CH 3 )CH 2 -O-(C 2 H 4 O) n -H, C 13 H 27 -O-(C 2 H4 O) n -(CH(CH 3 )CH 2 O)-H, C 16 H 33 -O-(C 2 H 4 O) n -H, HC(C 5 H 11 )(C 7 H 15 )-O-(C 2 H 4 O) n -H (in each formula, n is an integer of 1 or more), etc. may be mentioned. Examples of commercially available products of the above polyoxyethylene alkyl ether include, for example, Genapol X series (manufactured by Clariant) such as Genapol X080 (trade name), Neugen TDS series (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) such as Neugen TDS-80 (trade name), Leocol TD series (manufactured by Lion Corporation) such as Leocol TD-90 (trade name), Lionol (registered trademark) TD series (manufactured by Lion Corporation), T-Det A series (manufactured by Harcros Chemicals) such as T-Det A138 (trade name), Tergitol (registered trademark) 15-S series (manufactured by The Dow Chemical Company), etc.

[0085] The above nonionic surfactant is preferably an ethoxylate of 2,6,8-trimethyl-4-nonanol having an average of about 4 to about 18 ethylene oxide units, an ethoxylate of 2,6,8-trimethyl-4-nonanol having an average of about 6 to about 12 ethylene oxide units, or a mixture thereof. This type of nonionic surfactant is also commercially available, for example, as TERGITOL TMN-6, TERGITOL TMN-10, and TERGITOL TMN-100X (all trade names, manufactured by The Dow Chemical Company).

[0086] Also, the hydrophobic group of the nonionic surfactant may be any of an alkylphenol group, a linear alkyl group, and a branched alkyl group. For example, as the nonionic surfactant, for example, general formula (ii) R 7 -C6 H 4 -O-A 2 -H (ii) (In the formula, R 7 is a linear or branched alkyl group having 4 to 12 carbon atoms, and A 2 is a polyoxyalkylene chain.) Examples of the nonionic surfactant represented by the formula include. Specific examples of the nonionic surfactant include Triton (registered trademark) X-100 (trade name, manufactured by Dow Chemical Company), etc.

[0087] A 2 The polyoxyalkylene chain of may be composed of oxyethylene and oxypropylene. It is a polyoxyalkylene chain consisting of an average repeat number of 5 to 20 of oxyethylene groups and an average repeat number of 0 to 2 of oxypropylene groups, and is a hydrophilic group. The number of oxyethylene units may include either a broad or narrow unimodal distribution that is normally provided, or a broader or bimodal distribution obtained by blending. When the average repeat number of oxypropylene groups exceeds 0, the oxyethylene groups and oxypropylene groups in the polyoxyalkylene chain may be arranged in a block or random manner. From the viewpoints of the viscosity and sedimentation stability of the composition, a polyoxyalkylene chain composed of an average repeat number of 7 to 12 of oxyethylene groups and an average repeat number of 0 to 2 of oxypropylene groups is preferable. Particularly, when A 2 has an average of 0.5 to 1.5 oxypropylene groups, it has good low foaming property and is preferable.

[0088] More preferably, R 7 is a primary or secondary alkyl group, more preferably (R’)(R’’)HC-, where R’ and R’’ are the same or different linear, branched, or cyclic alkyl groups, and the total amount of carbon atoms is at least 5, preferably 7 to 17. Preferably, at least one of R’ or R’’ is a branched or cyclic hydrocarbon group.

[0089] Examples of the nonionic surfactant include polyol compounds. Specifically, those described in International Publication No. WO2011 / 014715 and the like can be mentioned. Typical examples of the polyol compound include compounds having one or more sugar units as polyol units. The sugar unit may be modified so as to contain at least one long chain. Suitable polyol compounds containing at least one long chain portion include, for example, alkyl glycosides, modified alkyl glycosides, sugar esters, and combinations thereof. Examples of the sugar include, but are not limited to, monosaccharides, oligosaccharides, and sorbitan. Examples of the monosaccharide include pentoses and hexoses. Typical examples of the monosaccharide include ribose, glucose, galactose, mannose, fructose, arabinose, and xylose. Examples of the oligosaccharide include oligomers of 2 to 10 identical or different monosaccharides. Examples of the oligosaccharide include, but are not limited to, sucrose, maltose, lactose, raffinose, and isomaltose.

[0090] Typically, suitable sugars for use as polyol compounds include cyclic compounds containing a five-membered ring of 4 carbon atoms and 1 heteroatom (typically oxygen or sulfur, preferably an oxygen atom), or cyclic compounds containing a six-membered ring of 5 carbon atoms and 1 heteroatom as described above, preferably an oxygen atom. These further contain at least 2 or at least 3 hydroxy groups (-OH groups) bonded to the carbocyclic atoms. Typically, the sugar is modified in that one or more of the hydrogen atoms of the hydroxy group (and / or hydroxyalkyl group) bonded to the carbocyclic atom are substituted by a long chain residue such that an ether or ester bond is created between the long chain residue and the sugar moiety. The sugar-based polyol may contain one sugar unit or a plurality of sugar units. One sugar unit or a plurality of sugar units may be modified with a long chain portion as described above. Specific examples of the sugar-based polyol compounds include glycosides, sugar esters, sorbitan esters, and mixtures and combinations thereof.

[0091] Preferred types of polyol compounds are alkyl or modified alkyl glucosides. These types of surfactants contain at least one glucose moiety.

Chemical formula

[0092] Examples of other nonionic surfactants include bifunctional block copolymers supplied by BASF as the Pluronic® R series and tridecyl alcohol alkoxylates supplied by BASF as the Iconol® TDA series.

[0093] As the nonionic surfactant, at least one selected from the group consisting of a nonionic surfactant represented by the general formula (i) and a nonionic surfactant represented by the general formula (ii) is preferable, and a nonionic surfactant represented by the general formula (i) is more preferable.

[0094] The nonionic surfactant preferably does not contain an aromatic moiety.

[0095] The content of the nonionic surfactant in the composition to be concentrated is preferably 1.0% by mass or more, preferably 40% by mass or less, more preferably 30% by mass or less, and still more preferably 25% by mass or less with respect to the fluoropolymer. If the content of the fluorine-free nonionic surfactant is too small, concentration may be difficult, and if the content of the fluorine-free nonionic surfactant is too large, the economy may be impaired.

[0096] The content of the nonionic surfactant is a value calculated according to the formula: N = [(Y - Z) / X] × 100 (% by mass), where about 1 g (X g) of the sample is heated at 110°C for 30 minutes to obtain a heating residue (Y g), and further, the obtained heating residue (Y g) is heated at 300°C for 30 minutes to obtain a heating residue (Z g).

[0097] (Concentration) Examples of the concentration method include phase separation concentration, electrophoresis, ion exchanger method, membrane concentration, etc. Phase separation concentration, ion exchanger method, and membrane concentration can be carried out under conventionally known treatment conditions and are not particularly limited, but can be carried out by the methods described in International Publication No. 2004 / 050719, Japanese Patent Application Laid-Open No. 2002-532583, and Japanese Patent Application Laid-Open No. 55-120630.

[0098] As the concentration method, phase separation concentration is preferred. Phase separation concentration can be carried out, for example, by heating the composition to cause phase separation into a fluoropolymer-free phase (upper phase) and a fluoropolymer-containing phase (concentrated phase), removing the fluoropolymer-free phase, and recovering the fluoropolymer-containing phase (concentrated phase).

[0099] The recovered fluoropolymer-containing phase (concentrated phase) contains a fluoropolymer, a nonionic surfactant, a fluorine-free anionic surfactant, and an aqueous medium, and also contains polymer (I) with a reduced content compared to before concentration.

[0100] The temperature for phase separation concentration can be selected based on the cloud point of the nonionic surfactant contained in the composition. The temperature for phase separation concentration is preferably not lower than a temperature 10°C lower than the cloud point of the nonionic surfactant, and preferably not higher than a temperature 10°C higher than the cloud point of the nonionic surfactant.

[0101] In the production method of the present disclosure, it is also preferable to repeat the phase separation concentration. By repeating the phase separation concentration, the content of the polymer (I) in the composition can be easily reduced to a desired content.

[0102] The number of repetitions is not particularly limited, but is preferably 2 or more, more preferably 3 or more. The upper limit of the number is not limited, but may be, for example, 10 or less. By repeating the phase separation concentration, the content of the polymer (I) can be further reduced.

[0103] When the phase separation concentration is performed two or more times, it is preferable that the first phase separation concentration is heated at a temperature not lower than a temperature 10°C lower than the cloud point of the nonionic surfactant and then allowed to stand, and is separated into a supernatant phase and a concentrated phase. Further, it is preferable that the second or subsequent phase separation concentration is heated at a temperature not lower than a temperature 10°C lower than the cloud point of the nonionic surfactant and then allowed to stand, and is separated into a supernatant phase and a concentrated phase.

[0104] When repeating the phase separation concentration a plurality of times in the production method of the present disclosure, the first phase separation concentration is preferably also carried out in the presence of a fluorine-free anionic surfactant. The composition used in the first phase separation concentration contains more polymer (I) than the composition used in the second and subsequent phase separation concentrations. However, even in a state where the content of the polymer (I) is high, by making the fluorine-free anionic surfactant present, both the rate of increasing the concentration of the fluoropolymer in the composition and the rate of removing the polymer (I) in the composition can be increased, and finally the concentration of the fluoropolymer in the obtained aqueous dispersion becomes high.

[0105] When repeating the phase separation concentration multiple times, except for the final phase separation concentration, when the solid content concentration of the fluoropolymer in the composition reaches 48 to 52% by mass, the phase separation concentration is stopped, an aqueous medium is added to the concentrated composition, and then the phase separation concentration can be repeated. By stopping the phase separation concentration when the solid content concentration of the fluoropolymer reaches the above range, each phase separation concentration can be completed in a short time without reducing the removal efficiency of the polymer (I) in each phase separation concentration. As a result, the total time required for the phase separation concentration can be shortened.

[0106] The pH of the composition to be concentrated is preferably 4.0 to 11.5, more preferably 7.0 or more, still more preferably 8.0 or more, and particularly preferably 9.0 or more. By adjusting the pH of the composition within the above range, both the rate of increasing the concentration of the fluoropolymer in the composition and the rate of removing the polymer (I) in the composition can be increased, and finally, the concentration of the fluoropolymer in the obtained aqueous dispersion will be high.

[0107] (Polymer (I)) The polymer (I) used in the production method of the present disclosure is a polymer containing a polymerization unit (I) based on the monomer (I). The monomer (I) is represented by the following general formula (I). CX 1 X 3 =CX 2 R(-CZ 1 Z 2 -A 0 ) m (I) (In the formula, X 1 and X 3 are each independently F, Cl, H or CF 3 ; X 2 is H, F, an alkyl group or a fluorinated alkyl group; A 0 is an anionic group; R is a linking group; Z 1 and Z 2 are each independently H, F, an alkyl group or a fluorinated alkyl group; m is an integer of 1 or more.) X 2 is preferably F, Cl, H or CF 3 . Also, Z 1 and Z 2 are preferably F or CF 3 .

[0108] In the present disclosure, the anionic group includes, in addition to anionic groups such as a sulfate group and a carboxylate group, a functional group that gives an anionic group such as an acid group like -COOH and an acid-base like -COONH 4 . The anionic group includes a sulfate group, a carboxylate group, a phosphate group, a phosphonate group, a sulfonate group, or -C(CF 3 ) 2 OM (wherein M is -H, a metal atom, -NR 7 4 , an optionally substituted imidazolium, an optionally substituted pyridinium or an optionally substituted phosphonium, and R 7 is H or an organic group).) is preferred.

[0109] In the production method of the present disclosure, as the monomer (I) represented by the general formula (I), one or more monomers can be used.

[0110] R is a linking group. In the present disclosure, the "linking group" is an (m + 1)-valent linking group, and when m is 1, it is a divalent linking group. The linking group may be a single bond, 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.

[0111] The linking group may be linear or branched, cyclic or acyclic, saturated or unsaturated, substituted or unsubstituted, and may optionally contain one or more heteroatoms selected from the group consisting of sulfur, oxygen, and nitrogen, and may optionally contain one or more functional groups selected from the group consisting of ester, amide, sulfonamide, carbonyl, carbonate, urethane, urea, and carbamate. The linking group may not contain a carbon atom and may be a chain heteroatom such as oxygen, sulfur, or nitrogen.

[0112] m is an integer of 1 or more, preferably 1 or 2, more preferably 1. When m is an integer of 2 or more, Z 1 , Z 2 and A 0 may be the same or different. Next, a preferred configuration when m is 1 in the general formula (I) will be described.

[0113] R is preferably, for example, a chain heteroatom such as oxygen, sulfur, or nitrogen, or a divalent organic group.

[0114] When R is a divalent organic group, the hydrogen atom bonded to the carbon atom may be replaced by a halogen other than fluorine, such as chlorine, and may or may not contain a double bond. Also, R may be either linear or branched, and may be either cyclic or acyclic. Further, R may contain a functional group (for example, ester, ether, ketone (keto group), amine, halide, etc.).

[0115] R may also be a non-fluorine divalent organic group or a partially fluorinated or perfluorinated divalent organic group.

[0116] Examples of R include a hydrocarbon group in which no fluorine atom is bonded to a carbon atom, a hydrocarbon group in which some of the hydrogen atoms bonded to a carbon atom are substituted with fluorine atoms, or a hydrocarbon group in which all of the hydrogen atoms bonded to a carbon atom are substituted with fluorine atoms. These may contain an oxygen atom, a double bond, or a functional group.

[0117] R is preferably a hydrocarbon group having 1 to 100 carbon atoms which may contain an ether bond or a keto group, and some or all of the hydrogen atoms bonded to the carbon atoms of the hydrocarbon group may be substituted with fluorine.

[0118] R is preferably - (CH 2 ) a -, - (CF 2 ) a -, - O - (CF 2 ) a -, - (CF 2 ) a - O - (CF 2 ) b -, - O(CF 2 ) a - O - (CF 2 ) b -, - (CF 2 ) a - [O - (CF 2 ) b ) c -, - O(CF 2 ) a - [O - (CF 2 ) b ) c -, - [(CF 2 ) a - O] b - [(CF 2 ) c - O] d -, - O[(CF 2 ) a - O] b - [(CF 2 ) c - O] d -, - O - [CF 2 CF(CF 3 )O] a - (CF2 ) b -,-[CF 2 CF(CF 3 )O] a -,-[CF(CF 3 )CF 2 O] a -,-(CF 2 ) a -O-[CF(CF 3 )CF 2 O] a -,-(CF 2 ) a -O-[CF(CF 3 )CF 2 O] a -(CF 2 ) b -,-[CF 2 CF(CF 3 )] a -CO-(CF 2 ) b - and at least one selected from combinations thereof. Wherein a, b, c and d are each independently at least 1 or more. a, b, c and d may each independently be 2 or more, 3 or more, 4 or more, 10 or more, 20 or more. The upper limit of a, b, c and d is, for example, 100.

[0119] R is represented by the general formula (r1): -CF 2 -O-(CX 6 2 ) e -{O-CF(CF 3 )} f -(O) g - (r1) (wherein X 6 are each independently H, F or CF 3 and e is an integer from 0 to 3, f is an integer from 0 to 3, and g is 0 or 1) is preferred, and the general formula (r2): -CF 2 -O-(CX 7 2 ) e -(O) g - (r2) (wherein X 7 is independently H, F or CF 3 , e is an integer from 0 to 3, and g is 0 or 1) is more preferred.

[0120] Specific examples suitable as R include -CF 2 -O-, -CF 2 -O-CF 2 -, -CF 2 -O-CH 2 -, -CF 2 -O-CH 2 CF 2 -, -CF 2 -O-CF 2 CF 2 -, -CF 2 -O-CF 2 CH 2 -, -CF 2 -O-CF 2 CF 2 CH 2 -, -CF 2 -O-CF(CF 3 )-, -CF 2 -O-CF(CF 3 )CF 2 -, -CF 2 -O-CF(CF 3 )CF 2 -O-, -CF 2 -O-CF(CF 3 )CF 2 -O-CF 2 -, -CF 2 -O-CF(CF 3 )CH 2 - etc. Among them, R is preferably a perfluoroalkylene group which may contain an oxygen atom. Specifically, -CF 2 -O-, -CF 2 -O-CF 2 -, -CF 2 -O-CF 2 CF 2 -, -CF 2 -O-CF(CF 3 )-, -CF 2 -O-CF(CF 3 )CF 2-, or -CF 2 -O-CF(CF 3 )CF 2 -O- is preferred.

[0121] -R-CZ in general formula (I) 1 Z 2 - as, general formula (s1): -CF 2 -O-(CX 6 2 ) e -{O-CF(CF 3 )} f -(O) g -CZ 1 Z 2 - (s1) (wherein X 6 is each independently H, F or CF 3 and e is an integer from 0 to 3, f is an integer from 0 to 3, g is 0 or 1, and Z 1 and Z 2 are each independently H, F, an alkyl group or a fluorinated alkyl group), and in formula (s1), Z 1 and Z 2 are more preferably F or CF 3 and it is even more preferable that one is F and the other is CF 3 .

[0122] Also, in general formula (I), -R-CZ 1 Z 2 - as, general formula (s2): -CF 2 -O-(CX 7 2 ) e -(O) g -CZ 1 Z 2 - (s2) (wherein X 7 is each independently H, F or CF 3 and e is an integer from 0 to 3, g is 0 or 1, and Z 1 and Z 2is preferably independently represented by H, F, an alkyl group, or a fluorinated alkyl group. In formula (s2), Z 1 and Z 2 are more preferably F or CF 3 and even more preferably one is F and the other is CF 3 .

[0123] -R-CZ in general formula (I) 1 Z 2 - includes -CF 2 -O-CF 2 -, -CF 2 -O-CF(CF 3 )-, -CF 2 -O-C(CF 3 ) 2 -, -CF 2 -O-CF 2 -CF 2 -, -CF 2 -O-CF 2 -CF(CF 3 )-, -CF 2 -O-CF 2 -C(CF 3 ) 2 -, -CF 2 -O-CF 2 CF 2 -CF 2 -, -CF 2 -O-CF 2 CF 2 -CF(CF 3 )-, -CF 2 -O-CF 2 CF 2 -C(CF 3 ) 2 -, -CF 2 -O-CF(CF 3 )-CF 2 -, -CF 2 -O-CF(CF 3 )-CF(CF 3 )-, -CF 2 -O-CF(CF 3 )-C(CF 3 ) 2 -, -CF 2 -O-CF(CF 3 )CF2 -CF 2 -、 -CF 2 -O-CF(CF 3 )CF 2 -CF(CF 3 )-、 -CF 2 -O-CF(CF 3 )CF 2 -C(CF 3 ) 2 -、 -CF 2 -O-CF(CF 3 )CF 2 -O-CF 2 -、 -CF 2 -O-CF(CF 3 )CF 2 -O-CF(CF 3 )-、 or, -CF 2 -O-CF(CF 3 )CF 2 -O-C(CF 3 ) 2 - is preferred, -CF 2 -O-CF(CF 3 )-、 -CF 2 -O-CF 2 -CF(CF 3 )-、 -CF 2 -O-CF 2 CF 2 -CF(CF 3 )-、 -CF 2 -O-CF(CF 3 )-CF(CF 3 )-、 -CF 2 -O-CF(CF 3 )CF 2 -CF(CF 3 )-、 or, -CF 2 -O-CF(CF 3 )CF 2 -O-CF(CF 3 )- is more preferred.

[0124] It is also preferred that the polymer (I) is highly fluorinated. For example, the phosphate group moiety (e.g., CH 2 OP(O)(OM) 2 ) and the sulfate group moiety (e.g., CH 2 OS(O)2 An anionic group (A 0 ), excluding, it is preferable that 80% or more, 90% or more, 95% or more, or 100% of the C-H bonds in the polymer (I) are substituted with C-F bonds.

[0125] The monomer (I) and the polymer (I) preferably have a C-F bond and no C-H bond, excluding the anionic group (A 0 ). That is, in the general formula (I), X 1 , X 2 , and X 3 are all preferably F, and R is preferably a perfluoroalkylene group having 1 or more carbon atoms. The perfluoroalkylene group may be either linear or branched, cyclic or acyclic, and may contain at least one chain heteroatom. The number of carbon atoms of the perfluoroalkylene group may be 2 to 20, or may be 4 to 18.

[0126] The monomer (I) and the polymer (I) may be partially fluorinated. That is, the monomer (I) and the polymer (I) preferably have at least one hydrogen atom bonded to a carbon atom and at least one fluorine atom bonded to a carbon atom, excluding the anionic group (A 0 ).

[0127] The anionic group (A 0 ) is -SO 3 M, -OSO 3 M, -COOM, -SO 2 NR’CH 2 COOM, -CH 2 OP(O)(OM) 2 , [-CH 2 O] 2 P(O)(OM), -CH 2 CH 2 OP(O)(OM) 2 , [-CH 2 CH 2 O] 2 P(O)(OM), -CH 2 CH 2 OSO3 M, -P(O)(OM) 2 , -SO 2 NR’CH 2 CH 2 OP(O)(OM) 2 , [-SO 2 NR’CH 2 CH 2 O] 2 P(O)(OM), -CH 2 OSO 3 M, -SO 2 NR’CH 2 CH 2 OSO 3 M, or -C(CF 3 ) 2 OM may be. Among them, -SO 3 M, -OSO 3 M, -COOM, -P(O)(OM) 2 or -C(CF 3 ) 2 OM is preferred, -COOM, -SO 3 M, -OSO 3 M or -C(CF 3 ) 2 OM is more preferred, -SO 3 M, -COOM or -P(O)(OM) 2 is even more preferred, -SO 3 M or -COOM is particularly preferred, and -COOM is most preferred.

[0128] M is H, a metal atom, NR 7 4 , an imidazolium which may have a substituent, a pyridinium which may have a substituent or a phosphonium which may have a substituent, and R 7 is H or an organic group.

[0129] Examples of the metal atom include an alkali metal (Group 1), an alkaline earth metal (Group 2), etc., and Na, K or Li is preferred.

[0130] Examples of M include -H, a metal atom or NR 7 4is preferred, -H, an alkali metal (Group 1), an alkaline earth metal (Group 2) or NR 7 4 is more preferred, -H, -Na, -K, -Li or NH 4 is still more preferred, -H, -Na, -K or NH 4 is even more preferred, -H, -Na or NH 4 is particularly preferred, -H or -NH 4 is most preferred.

[0131] In polymer (I), each polymerization unit (I) may have different anionic groups or the same anionic group.

[0132] Monomer (I) is preferably a monomer represented by general formula (Ia). Polymer (I) is preferably a polymer containing a polymerization unit (Ia) based on the monomer represented by general formula (Ia). CF 2 =CF - O - Rf 0 -A 0 (Ia) (In the formula, A 0 is an anionic group, and Rf 0 is perfluorinated and may be linear or branched, cyclic or acyclic, saturated or unsaturated, substituted or unsubstituted, and is a perfluorinated divalent linking group optionally additionally containing one or more heteroatoms selected from the group consisting of sulfur, oxygen, and nitrogen.)

[0133] Monomer (I) is preferably a monomer represented by general formula (Ib). Polymer (I) is preferably a polymer containing a polymerization unit (Ib) based on the monomer represented by general formula (Ib). CH 2 =CH - O - Rf 0 -A 0 (Ib) (In the formula, A 0 is an anionic group, and Rf 0 is the perfluorinated divalent linking group defined in formula Ia.)

[0134] In general formula (I), A 0 is preferably one form that is a sulfate group. A 0 is, for example, -CH 2 OSO 3 M, -CH 2 CH 2 OSO 3 M, or -SO 2 NR’CH 2 CH 2 OSO 3 M, where R’ is H or an alkyl group having 1 to 4 carbon atoms, and M is the same as above.

[0135] A 0 When A is a sulfate group, examples of the monomer represented by general formula (I) include CF 2 =CF(OCF 2 CF 2 CH 2 OSO 3 M), CH 2 =CH((CF 2 ) 4 CH 2 OSO 3 M), CF 2 =CF(O(CF 2 ) 4 CH 2 OSO 3 M), CF 2 =CF(OCF 2 CF(CF 3 )CH 2 OSO 3 M), CF 2 =CF(OCF 2 CF(CF 3 )OCF 2 CF 2 CH 2 OSO 3 M), CH 2 =CH((CF 2 ) 4 CH 2 OSO 3 M), CF 2 =CF(OCF 2 CF 2 SO 2 N(CH 3 )CH2 CH 2 OSO 3 M), CH 2 =CH(CF 2 CF 2 CH 2 OSO 3 M), CF 2 =CF(OCF 2 CF 2 CF 2 CF 2 SO 2 N(CH 3 )CH 2 CH 2 OSO 3 M), CH 2 =CH(CF 2 CF 2 CF 2 CH 2 OSO 3 M), etc. may be mentioned. In the above formula, M is the same as above.

[0136] In general formula (I), A 0 being a sulfonate group is also one of the preferred forms. A 0 is, for example, -SO 3 M, where M is the same as above.

[0137] A 0 being a sulfonate group, examples of the monomer represented by general formula (I) include CF 2 =CF(OCF 2 CF 2 SO 3 M), CF 2 =CF(O(CF 2 ) 3 SO 3 M), CF 2 =CF(O(CF 2 ) 4 SO 3 M), CF 2 =CF(OCF 2 CF(CF 3 )SO 3 M), CF 2 =CF(OCF 2 CF(CF 3 )OCF 2 CF2 SO 3 M), CH 2 =CH(CF 2 CF 2 SO 3 M), CF 2 =CF(OCF 2 CF(CF 3 )OCF 2 CF 2 CF 2 CF 2 SO 3 M), CH 2 =CH((CF 2 ) 4 SO 3 M), CH 2 =CH((CF 2 ) 3 SO 3 M), etc. may be mentioned. In the above formula, M is the same as above.

[0138] In general formula (I), A 0 being a carboxylate group is also one of the preferred forms. As A 0 , for example, it is COOM or SO 2 NR’CH 2 COOM, where R’ is H or an alkyl group having 1 to 4 carbon atoms, and M is the same as above. When A 0 is a carboxylate group, examples of the monomer represented by general formula (I) include CF 2 =CF(OCF 2 CF 2 COOM), CF 2 =CF(O(CF 2 )) 3 COOM), CF 2 =CF(O(CF 2 )) 4 COOM), CF 2 =CF(O(CF 2 )) 5 COOM), CF 2 =CF(OCF 2 CF(CF 3 ))COOM), CF 2 =CF(OCF 2 CF(CF 3 )O(CF 2 ))n COOM)(n is greater than 1), CH 2 =CH(CF 2 CF 2 COOM), CH 2 =CH((CF 2 ) 4 COOM), CH 2 =CH((CF 2 ) 3 COOM), CF 2 =CF(OCF 2 CF 2 SO 2 NR’CH 2 COOM), CF 2 =CF(O(CF 2 ) 4 SO 2 NR’CH 2 COOM), CF 2 =CF(OCF 2 CF(CF 3 )SO 2 NR’CH 2 COOM), CF 2 =CF(OCF 2 CF(CF 3 )OCF 2 CF 2 SO 2 NR’CH 2 COOM), CH 2 =CH(CF 2 CF 2 SO 2 NR’CH 2 COOM), CF 2 =CF(OCF 2 CF(CF 3 )OCF 2 CF 2 CF 2 CF 2 SO 2 NR’CH 2 COOM), CH 2 =CH((CF 2 ) 4 SO 2 NR’CH 2 COOM), CH 2 =CH((CF 2 ) 3 SO 2 NR’CH 2Examples include COOM). In the above formula, R' is H or an alkyl group having 1 to 4 carbon atoms, and M is the same as above.

[0139] In general formula (I), A 0 being a phosphate group is also one of the preferred forms. A 0 For example, -CH 2 OP(O)(OM) 2 , [-CH 2 O] 2 P(O)(OM), -CH 2 CH 2 OP(O)(OM) 2 , [-CH 2 CH 2 O] 2 P(O)(OM), [-SO 2 NR’CH 2 CH 2 O] 2 P(O)(OM) or SO 2 NR’CH 2 CH 2 OP(O)(OM) 2 wherein R’ is an alkyl group having 1 to 4 carbon atoms, and M is the same as above.

[0140] A 0 When A is phosphate, examples of the monomer represented by general formula (I) include CF 2 =CF(OCF 2 CF 2 CH 2 OP(O)(OM) 2 ), CF 2 =CF(O(CF 2 ) 4 CH 2 OP(O)(OM) 2 ), CF 2 =CF(OCF 2 CF(CF 3 )CH 2 OP(O)(OM) 2 ), CF 2 =CF(OCF 2 CF(CF 3 )OCF 2 CF 2 CH 2OP(O)(OM) 2 )、CF 2 =CF(OCF 2 CF 2 SO 2 N(CH 3 )CH 2 CH 2 OP(O)(OM) 2 )、CF 2 =CF(OCF 2 CF 2 CF 2 CF 2 SO 2 N(CH 3 )CH 2 CH 2 OP(O)(OM) 2 )、CH 2 =CH(CF 2 CF 2 CH 2 OP(O)(OM) 2 )、CH 2 =CH((CF 2 ) 4 CH 2 OP(O)(OM) 2 )、CH 2 =CH((CF 2 ) 3 CH 2 OP(O)(OM) 2 ) etc. may be mentioned. In the above formula, M is the same as above.

[0141] In general formula (I), A 0 being a phosphonate group is also one of the preferred forms. When A 0 is a phosphonate group, examples of the monomer represented by general formula (I) include CF 2 =CF(OCF 2 CF 2 P(O)(OM) 2 )、CF 2 =CF(O(CF 2 ) 4 P(O)(OM) 2 )、CF 2 =CF(OCF 2 CF(CF 3 )P(O)(OM) 2 )、CF 2 =CF(OCF2 CF(CF 3 )OCF 2 CF 2 P(O)(OM) 2 )、CH 2 =CH(CF 2 CF 2 P(O)(OM) 2 )、CH 2 =CH((CF 2 ) 4 P(O)(OM) 2 )、CH 2 =CH((CF 2 ) 3 P(O)(OM) 2 ) are mentioned, where M is the same as above.

[0142] Monomer (I) is preferably the monomer (1) represented by the general formula (1). Polymer (I) is preferably the polymer (1) containing the polymerization unit (1) based on the monomer represented by the general formula (1). CX 2 =CY(-CZ 2 -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, Z is the same or different and is -H, -F, an alkyl group or a fluoroalkyl group. Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms, or a fluorine-containing alkylene group having an ether bond with 2 to 100 carbon atoms. A is -COOM, -SO 3 M, -OSO 3 M or -C(CF 3 ) 2 OM (M is -H, a metal atom, -NR 7 4 , imidazolium which may have a substituent, pyridinium which may have a substituent or phosphonium which may have a substituent, and R 7 is H or an organic group.). However, at least one of X, Y and Z contains a fluorine atom.)

[0143] In the production method of the present disclosure, the monomer (1) represented by the general formula (1) may be copolymerized with other monomers. The polymer (1) may be a homopolymer of the monomer (1) represented by the general formula (1), or a copolymer with other monomers.

[0144] The fluorine-containing alkylene group having 2 to 100 carbon atoms and an ether bond does not include a structure in which an oxygen atom is at the terminal, and is an alkylene group containing an ether bond between carbon atoms.

[0145] In the general formula (1), X is -H or F. Both X 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.

[0146] In the general formula (1), Y is -H, -F, an alkyl group or a fluorine-containing alkyl group. The alkyl group is an alkyl group that does not contain a fluorine atom and may have 1 or more carbon atoms. The number of carbon atoms of the alkyl group is preferably 6 or less, more preferably 4 or less, and still more preferably 3 or less. The fluorine-containing alkyl group is an alkyl group that contains at least one fluorine atom and may have 1 or more carbon atoms. The number of carbon atoms of the fluorine-containing alkyl group is preferably 6 or less, more preferably 4 or less, and still more preferably 3 or less. As the above Y, -H, -F or CF 3 is preferable, and -F is more preferable.

[0147] In the general formula (1), Z is the same or different and is -H, -F, an alkyl group or a fluoroalkyl group. The alkyl group is an alkyl group that does not contain a fluorine atom and may have 1 or more carbon atoms. The number of carbon atoms of the alkyl group is preferably 6 or less, more preferably 4 or less, and still more preferably 3 or less. The fluorine-containing alkyl group is an alkyl group that contains at least one fluorine atom and may have 1 or more carbon atoms. The number of carbon atoms of the fluorine-containing alkyl group is preferably 6 or less, more preferably 4 or less, and still more preferably 3 or less. As the above Z, -H, -F or CF 3is preferred, and -F is more preferred.

[0148] In general formula (1), at least one of X, Y, and Z contains a fluorine atom. For example, X may be -H, and Y and Z may be -F.

[0149] In general formula (1), Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms, or a fluorine-containing alkylene group having an ether bond and having 2 to 100 carbon atoms.

[0150] The number of carbon atoms of the fluorine-containing alkylene group is preferably 2 or more. Also, the number of carbon atoms of the fluorine-containing alkylene group is preferably 30 or less, more preferably 20 or less, still more preferably 10 or less, particularly preferably 6 or less, and most preferably 3 or less. Examples of the fluorine-containing alkylene group include -CF 2 -, -CH 2 CF 2 -, -CF 2 CF 2 -, -CF 2 CH 2 -, -CF 2 CF 2 CF 2 -, -CF 2 CF 2 CH 2 -, -CF(CF 3 )-, -CF(CF 3 )CF 2 -, -CF(CF 3 )CH 2 - etc. are included. The fluorine-containing alkylene group is preferably a perfluoroalkylene group.

[0151] The number of carbon atoms of the fluorine-containing alkylene group having an ether bond is preferably 3 or more. Also, the number of carbon atoms of the fluorine-containing alkylene group having an ether bond is preferably 60 or less, more preferably 30 or less, still more preferably 12 or less, particularly preferably 9 or less, and most preferably 6 or less. The fluorine-containing alkylene group having an ether bond is, for example, of the general formula:

Chemical formula

[0152] Specific examples of the fluorine-containing alkylene group having the ether bond include -CF 2 CF(CF 3 )OCF 2 CF 2 -, -CF(CF 3 )CF 2 -O-CF(CF 3 )-, -(CF(CF 3 )CF 2 -O) n -CF(CF 3 )-(wherein, n is an integer from 1 to 10), -CF(CF 3 )CF 2 -O-CF(CF 3 )CH 2 -, -(CF(CF 3 )CF 2 -O) n -CF(CF 3 )CH 2 -(wherein, n is an integer from 1 to 10), -CH 2 CF 2 CF 2 O-CH 2 CF 2 CH 2 -, -CF 2 CF 2 CF 2 O-CF 2 -, -CF 2 CF 2 CF 2 O-CF 2 CF 2 -, -CF 2 CF 2 CF 2 O-CF 2 CF 2 CF 2 -, -CF 2 CF2 CF 2 O-CF 2 CF 2 CH 2 -,-CF 2 CF 2 O-CF 2 -,-CF 2 CF 2 O-CF 2 CH 2 - etc. may be mentioned. The fluorine-containing alkylene group having the above ether bond is preferably a perfluoroalkylene group.

[0153] In the general formula (1), A is -COOM, -SO 3 M, -OSO 3 M or -C(CF 3 ) 2 OM (M is H, a metal atom, NR 7 4 , an imidazolium which may have a substituent, a pyridinium which may have a substituent or a phosphonium which may have a substituent, and R 7 is H or an organic group).

[0154] R 7 is preferably H or an organic group of C 1-10 , more preferably H or an organic group of C 1-4 , and still more preferably H or an alkyl group of C 1-4 .

[0155] Examples of the metal atom include alkali metals (Group 1), alkaline earth metals (Group 2), etc., and Na, K or Li is preferred.

[0156] M is preferably H, a metal atom or NR 7 4 , more preferably H, an alkali metal (Group 1), an alkaline earth metal (Group 2) or NR 7 4 , still more preferably H, Na, K, Li or NH 4 , still more preferably H, Na, K or NH 4 , still more preferably H, Na or NH 4is particularly preferred, and H or NH 4 is most preferred.

[0157] As A, -COOM or -SO 3 M is preferred, and -COOM is more preferred.

[0158] Examples of the monomer represented by the general formula (1) include, for example, the general formula (1a): CX 2 =CFCF 2 -O-(CF(CF 3 )CF 2 O) n5 -CF(CF 3 )-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 is the same as defined above.) Monomers represented by this are exemplified.

[0159] In the general formula (1a), n5 is preferably 0 or an integer of 1 to 5, more preferably 0, 1 or 2, and still more preferably 0 or 1, in terms of being able to obtain particles with a small primary particle diameter.

[0160] In the production method of the present disclosure, the monomer represented by the general formula (1a) and other monomers may be copolymerized. The polymer (1) may be a homopolymer of the monomer represented by the general formula (1a) or a copolymer with other monomers.

[0161] The monomer (1) is preferably a monomer represented by the general formula (1A). The polymerization unit (1) is preferably a polymerization unit (1A) based on the monomer represented by the general formula (1A). CH 2 =CF(-CF 2 -O-Rf-A) (1A) (In the formula, Rf and A are the same as above.)

[0162] In the production method of the present disclosure, the monomer represented by the general formula (1A) and another monomer may be copolymerized. The polymer (1) may be a homopolymer of the monomer represented by the general formula (1A) or a copolymer with another monomer.

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

[0164]

Chemical formula

[0165] (In the formula, Z 1 is F or CF 3 ; Z 2 and Z 3 are each H or F; Z 4 is H, F or CF 3 ; p1 + q1 + r1 is an integer from 0 to 10; s1 is 0 or 1; t1 is an integer from 0 to 5, provided that when both Z 3 and Z 4 are H, p1 + q1 + r1 + s1 is not 0; A is the same as defined above) monomers are exemplified. More specifically,

[0166]

Chemical formula

[0167] etc. are preferably exemplified, and among them

[0168]

Chemical formula

[0169] is preferably the case.

[0170] As the monomer represented by the general formula (1A), it is preferable that A in the formula (1A) is -COOM, and in particular, CH 2 =CFCF 2 OCF(CF 3)COOM, and CH 2 =CFCF 2 OCF(CF 3 )CF 2 OCF(CF 3 )COOM (where M is the same as defined above) is preferably at least one selected from the group consisting of, CH 2 =CFCF 2 OCF(CF 3 )COOM is more preferred.

[0171] In addition, examples of the monomer represented by the general formula (1) include monomers represented by the following formula. CF 2 =CFCF 2 -O-Rf-A (where Rf and A are the same as above)

[0172] More specifically,

Chemical Formula

[0173] The monomer (I) is preferably the monomer (2) represented by the general formula (2). The polymer (I) is preferably a polymer (2) containing a polymerization unit (2) based on the monomer represented by the general formula (2). CX 2 =CY(-O-Rf-A) (2) (where X is, independently or differently, -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 or a keto group with 2 to 100 carbon atoms. A is the same as above.)

[0174] In the production method of the present disclosure, the monomer (2) represented by the general formula (2) and other monomers may be copolymerized. The polymer (2) may be a homopolymer of the monomer represented by the general formula (2) or a copolymer with other monomers.

[0175] In 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 of them may be -F and the other may be -H, or both may be -H.

[0176] In general formula (2), Y is -H, -F, an alkyl group, or a fluorine-containing alkyl group. The alkyl group is an alkyl group that does not contain a fluorine atom, and the number of carbon atoms may be 1 or more. The number of carbon atoms of the above alkyl group is preferably 6 or less, more preferably 4 or less, and still more preferably 3 or less. The fluorine-containing alkyl group is an alkyl group that contains at least one fluorine atom, and the number of carbon atoms may be 1 or more. The number of carbon atoms of the above fluorine-containing alkyl group is preferably 6 or less, more preferably 4 or less, and still more preferably 3 or less. As Y, -H, -F or -CF 3 is preferable, and -F is more preferable.

[0177] In general formula (2), at least one of the above X and Y preferably contains a fluorine atom. For example, X may be -H, and Y and Z may be -F.

[0178] In general formula (2), the above Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms, a fluorine-containing alkylene group having an ether bond and having 2 to 100 carbon atoms, or a fluorine-containing alkylene group having a keto group and having 2 to 100 carbon atoms. Note that the fluorine-containing alkylene group having an ether bond and having 2 to 100 carbon atoms does not include a structure in which an oxygen atom is at the terminal, and is an alkylene group that contains an ether bond between carbon atoms.

[0179] The number of carbon atoms of the fluorine-containing alkylene group of Rf is preferably 2 or more. Also, it is preferably 30 or less, more preferably 20 or less, still more preferably 10 or less, and particularly preferably 5 or less. As the fluorine-containing alkylene group, -CF 2 -, -CH 2 CF 2 -, -CF 2 CF 2 -, -CF 2 CH 2-, -CF 2 CF 2 CH 2 -, -CF(CF 3 )-, -CF(CF 3 )CF 2 -, -CF(CF 3 )CH 2 -, -CF 2 CF 2 CF 2 -, CF 2 CF 2 CF 2 CF 2 - etc. may be mentioned. The fluorine-containing alkylene group is preferably a perfluoroalkylene group, more preferably an unbranched linear perfluoroalkylene group.

[0180] The number of carbon atoms of the fluorine-containing alkylene group having the above ether bond is preferably 3 or more. Also, the number of carbon atoms of the fluorine-containing alkylene group having the above ether bond is preferably 60 or less, more preferably 30 or less, still more preferably 12 or less, and particularly preferably 5 or less. The fluorine-containing alkylene group having the above ether bond is, for example, represented by the general formula:

Chemical formula

[0181] Specific examples of the fluorine-containing alkylene group having the above ether bond include -CF 2 CF(CF 3 )OCF 2 CF 2 -, -CF 2 CF(CF 3 )OCF 2 CF 2 -, -CF 2 CF(CF 3)OCF 2 CF 2 CF 2 -, -CF(CF 3 )CF 2 -O-CF(CF 3 )-, -(CF(CF 3 )CF 2 -O) n -CF(CF 3 )-(wherein n is an integer from 1 to 10), -CF(CF 3 )CF 2 -O-CF(CF 3 )CH 2 -, -(CF(CF 3 )CF 2 -O) n -CF(CF 3 )CH 2 -(wherein n is an integer from 1 to 10), -CH 2 CF 2 CF 2 O-CH 2 CF 2 CH 2 -, -CF 2 CF 2 CF 2 O-CF 2 -, -CF 2 CF 2 CF 2 O-CF 2 CF 2 -, -CF 2 CF 2 CF 2 O-CF 2 CF 2 CF 2 -, -CF 2 CF 2 CF 2 O-CF 2 CF 2 CH 2 -, -CF 2 CF 2 O-CF 2 -, -CF 2 CF 2 O-CF 2 CH 2 - etc. may be mentioned. The fluorine-containing alkylene group having the above ether bond is preferably a perfluoroalkylene group.

[0182] The number of carbon atoms of the fluorine-containing alkylene group having the keto group is preferably 3 or more. Further, the number of carbon atoms of the fluorine-containing alkylene group having the keto group is preferably 60 or less, more preferably 30 or less, still more preferably 12 or less, and particularly preferably 5 or less.

[0183] Specific examples of the fluorine-containing alkylene group having the keto group include -CF 2 CF(CF 3 )CO-CF 2 -, -CF 2 CF(CF 3 )CO-CF 2 CF 2 -, -CF 2 CF(CF 3 )CO-CF 2 CF 2 CF 2 -, -CF 2 CF(CF 3 )CO-CF 2 CF 2 CF 2 CF 2 - and the like. The fluorine-containing alkylene group having the keto group is preferably a perfluoroalkylene group.

[0184] Water may be added to the keto group in the fluorine-containing alkylene group. Therefore, the monomer (2) may be a hydrate. Examples of the fluorine-containing alkylene group in which water is added to the keto group include -CF 2 CF(CF 3 )C(OH) 2 -CF 2 -, -CF 2 CF(CF 3 )C(OH) 2 -CF 2 CF 2 -, -CF 2 CF(CF 3 )C(OH) 2 -CF 2 CF 2 CF 2 -, -CF 2 CF(CF 3 )C(OH) 2 -CF 2 CF 2CF 2 CF 2 - etc. can be mentioned.

[0185] The monomer represented by the general formula (2) is preferably at least one selected from the group consisting of the monomers represented by the general formulas (2a), (2b), (2c), (2d), (2e), (2f), and (2g). CF 2 =CF - O - (CF 2 ) n1 -A (2a) (In the formula, n1 represents an integer from 1 to 10, and A is the same as defined above.) CF 2 =CF - O - (CF 2 C(CF 3 )F) n2 -A (2b) (In the formula, n2 represents an integer from 1 to 5, and A is the same as defined above.) CF 2 =CF - O - (CFX 1 ) n3 -A (2c) (In the formula, X 1 represents F or CF 3 , n3 represents an integer from 1 to 10, and A is the same as defined above.) CF 2 =CF - O - (CF 2 CFX 1 O) n4 -(CF 2 ) n6 -A (2d) (In the formula, n4 represents an integer from 1 to 10, n6 represents an integer from 1 to 3, and A and X 1 are the same as defined above.) CF 2 =CF - O - (CF 2 CF 2 CFX 1 O) n5 -CF 2 CF 2 CF 2 -A (2e) (In the formula, n5 represents an integer from 0 to 10, and A and X 1 are the same as defined above.) CF 2=CF-O-(CF 2 ) n7 -O-(CF 2 ) n8 -A (2f) (wherein, n7 represents an integer of 1 to 10, n8 represents an integer of 1 to 3. A is the same as defined above.) CF 2 =CF[OCF 2 CF(CF 3 )] n9 O(CF 2 ) n10 O[CF(CF 3 )CF 2 O] n11 CF(CF 3 )-A (2g) (wherein, n9 represents an integer of 0 to 5, n10 represents an integer of 1 to 8, n11 represents an integer of 0 to 5. A is the same as defined above.)

[0186] In general formula (2a), it is preferable that the above n1 is an integer of 5 or less, and more preferably an integer of 2 or less.

[0187] Examples of the monomer represented by general formula (2a) include, for example, CF 2 =CF-O-CF 2 COOM, CF 2 =CF(OCF 2 CF 2 COOM), CF 2 =CF(O(CF 2 ) 3 COOM), CF 2 =CF(OCF 2 CF 2 SO 3 M), CF 2 =CFOCF 2 SO 3 M, CF 2 =CFOCF 2 CF 2 CF 2 SO 3 M (wherein, M is the same as defined above).

[0188] In general formula (2b), n2 is preferably an integer of 3 or less in terms of the dispersion stability of the resulting composition.

[0189] In general formula (2c), n3 is preferably an integer of 5 or less in terms of water solubility, A is preferably -COOM, and M is preferably H, Na, or NH 4 and preferably so on.

[0190] In general formula (2d), X 1 is preferably -CF 3 in terms of the dispersion stability of the composition, n4 is preferably an integer of 5 or less in terms of water solubility, A is preferably -COOM, and M is preferably H, Na, or NH 4 and preferably so on.

[0191] Examples of the monomer represented by general formula (2d) include CF 2 =CFOCF 2 CF(CF 3 )OCF 2 CF 2 COOM, CF 2 =CFOCF 2 CF(CF 3 )OCF 2 COOM, CF 2 =CFOCF 2 CF(CF 3 )OCF 2 CF 2 CF 2 COOM, CF 2 =CFOCF 2 CF(CF 3 )OCF 2 SO 3 M, CF 2 =CFOCF 2 CF(CF 3 )OCF 2 CF 2 SO 3 M, CF 2 =CFOCF 2 CF(CF 3 )OCF 2 CF 2 CF 2 SO3 M (wherein M represents H, NH 4 or an alkali metal). Examples thereof include

[0192] In general formula (2e), n5 is preferably an integer of 5 or less in terms of water solubility, A is preferably -COOM, and M is preferably H or NH 4 is preferred.

[0193] Examples of the monomer represented by general formula (2e) include, for example, CF 2 =CFOCF 2 CF 2 CF 2 COOM (wherein M represents H, Na, NH 4 or an alkali metal). Examples thereof include

[0194] In general formula (2f), n7 is preferably an integer of 5 or less in terms of water solubility, A is preferably -COOM or -SO 3 M, with -COOM being more preferred. M is preferably H, Na, K or NH 4 is preferred.

[0195] Examples of the monomer represented by general formula (2f) include, for example, CF 2 =CF-O-(CF 2 ) 3 -O-CF 2 -COOM (wherein M represents H, NH 4 or an alkali metal). Examples thereof include

[0196] In general formula (2g), n9 is preferably an integer of 3 or less in terms of water solubility, n10 is preferably an integer of 3 or less, n11 is preferably an integer of 3 or less, A is preferably -COOM or -SO 3 M, with -COOM being more preferred. M is preferably H, Na, K or NH 4 is preferred.

[0197] Examples of the monomer represented by general formula (2g) include, for example, CF2 =CFO(CF 2 ) 2 OCFO(CF 3 )COOM, CF 2 =CFOCF 2 CF 2 OCFO(CF 3 )CF 2 OCFO(CF 3 )COOM, CF 2 =CFOCF 2 CFO(CF 3 )OCF 2 CF 2 OCFO(CF 3 )COOM, CF 2 =CF[OCF 2 CFO(CF 3 )] 2 O(CF 2 ) 2 O[CFO(CF 3 )CF 2 O]CFO(CF 3 )COOM, CF 2 =CF[OCF 2 CFO(CF 3 )] 3 O(CF 2 ) 2 O[CFO(CF 3 )CF 2 O] 3 CFO(CF 3 )COOM (wherein, M represents H, NH 4 or an alkali metal.) is exemplified.

[0198] The monomer (I) is preferably the monomer (3) represented by the general formula (3). The polymer (I) is preferably the polymer (3) containing the polymerization unit (3) based on the monomer represented by the general formula (3). CX 2 =CY(-Rf-A) (3) (wherein, X is the same or different and is -H or F, Y is -H, -F, an alkyl group or a fluorine-containing alkyl group, Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms, or a fluorine-containing alkylene group having an ether bond and having 2 to 100 carbon atoms. A is the same as described above.)

[0199] In the production method of the present disclosure, the monomer (3) represented by the general formula (3) and other monomers may be copolymerized. The polymer (3) may be a homopolymer of the monomer represented by the general formula (3) or a copolymer with other monomers.

[0200] The fluorine-containing alkylene group having an ether bond with 2 to 100 carbon atoms does not include a structure in which an oxygen atom is at the end and is an alkylene group containing an ether bond between carbon-carbon bonds.

[0201] 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.

[0202] The monomer represented by the general formula (3) is a monomer represented by the general formula (3a): CF 2 =CF-(CF 2 ) n1 -A (3a) (In the formula, n1 represents an integer of 1 to 10, and A is the same as the above definition.) and a monomer represented by the general formula (3b): CF 2 =CF-(CF 2 C(CF 3 )F) n2 -A (3b) (In the formula, n2 represents an integer of 1 to 5, and A is the same as the above definition.) and at least one selected from the group consisting of monomers represented by the formula is preferred.

[0203] In the general formulas (3a) and (3b), A is preferably -SO 3 M or COOM, and M is H, a metal atom, NR 7 4 , an imidazolium which may have a substituent, a pyridinium which may have a substituent or a phosphonium which may have a substituent. R 7 represents H or an organic group.

[0204] In general formula (3a), n1 is preferably an integer of 5 or less, more preferably an integer of 2 or less. A is preferably -COOM, and M is preferably H or NH 4 is preferably.

[0205] Examples of the monomer represented by general formula (3a) include CF 2 =CFCF 2 COOM (wherein M is the same as defined above).

[0206] In general formula (3b), n2 is preferably an integer of 3 or less from the viewpoint of the dispersion stability of the resulting composition. A is preferably -COOM, and M is preferably H or NH 4 is preferably.

[0207] Next, a preferred configuration when m is an integer of 2 or more in general formula (I) will be described.

[0208] The monomer (I) is also preferably at least one selected from the group consisting of monomers represented by general formula (4a) and general formula (4b). The polymer (I) is also preferably a polymer (4) containing a polymerization unit (4) based on at least one monomer selected from the group consisting of monomers represented by general formula (4a) and general formula (4b). CF 2 =CF-CF 2 -O-Q F1 -CF(-Q F2 -CZ 1 Z 2 -A) 2 (4a) (wherein Z 1 , Z 2 and A are the same as defined above, Q F1 and Q F2 are the same or different and are a single bond, a fluorine-containing alkylene group which may contain an ether bond between carbon atoms, or a fluorine-containing oxyalkylene group which may contain an ether bond between carbon atoms) CF2 =CF - O - Q F1 -CF(-Q F2 -CZ 1 Z 2 -A) 2 (4b) (wherein, Z 1 、Z 2 、A, Q F1 and Q F2 are the same as defined above)

[0209] Examples of the monomers represented by general formula (4a) and general formula (4b) include

Chemical formula

[0210] As the monomer (I), at least one selected from the group consisting of monomer (1), monomer (2) and monomer (3) is preferable, monomer (1) is more preferable, and monomer (1A) is even more preferable. As the polymer (I), at least one selected from the group consisting of polymer (1), polymer (2) and polymer (3) is preferable, and polymer (1) is more preferable.

[0211] In the production method of the present disclosure, the monomer (I) and other monomers may be copolymerized. The polymer (I) may be a homopolymer consisting only of the polymerization unit (I), or may be a copolymer containing the polymerization unit (I) and a polymerization unit based on another monomer copolymerizable with the monomer represented by the general formula (I). From the viewpoint of solubility in an aqueous medium, a homopolymer consisting only of the polymerization unit (I) is preferable. The polymerization unit (I) may be the same or different at each occurrence, and the polymer (I) may contain polymerization units (I) based on two or more different monomers represented by the general formula (I).

[0212] Examples of the above other monomers include the general formula CFR = CR 2(In the formula, R is independently H, F, or a perfluoroalkyl group having 1 to 4 carbon atoms), and the monomer represented thereby is preferable. As other monomers, fluorine-containing ethylenically unsaturated monomers having 2 or 3 carbon atoms are preferable. As other monomers, for example, CF 2 =CF 2 、CF 2 =CFCl、CH 2 =CF 2 、CFH=CH 2 、CFH=CF 2 、CF 2 =CFCF 3 、CH 2 =CFCF 3 、CH 2 =CHCF 3 、CHF=CHCF 3 (E isomer), CHF=CHCF 3 (Z isomer), etc. may be mentioned. Among them, in terms of good copolymerizability, tetrafluoroethylene (CF 2 =CF 2 ), chlorotrifluoroethylene (CF 2 =CFCl) and vinylidene fluoride (CH 2 =CF 2 ) at least one selected from the group consisting of is preferable, and at least one selected from the group consisting of tetrafluoroethylene and vinylidene fluoride is more preferable. Therefore, the polymerization unit based on the above other monomer is preferably a polymerization unit based on tetrafluoroethylene. The polymerization units based on the above other monomers may be the same or different in each occurrence, and the polymer (I) may contain polymerization units based on two or more different other monomers.

[0213] As the above other monomers, also, the general formula (n1-2):

[0214]

Chemical formula

[0215] (In the formula, X 1 , X 2 are the same or different and are H or F; X3 is H, F, Cl, CH 3 or CF 3 ; X 4 , X 5 is the same or different and is H or F; a and c are the same or different and are 0 or 1. Rf 3 is a monomer represented by a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having an ether bond and having 2 to 100 carbon atoms).

[0216] Specifically, CH 2 =CFCF 2 -O-Rf 3 , CF 2 =CF-O-Rf 3 , CF 2 =CFCF 2 -O-Rf 3 , CF 2 =CF-Rf 3 , CH 2 =CH-Rf 3 , CH 2 =CH-O-Rf 3 (wherein, Rf 3 is the same as the above formula (n1-2)) and the like are preferably exemplified.

[0217] As the other monomer, the formula (n2-1):

[0218]

Chemical formula

[0219] (wherein, X 9 is H, F or CH 3 ; Rf 4 is a fluorine-containing acrylate monomer represented by a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having an ether bond and having 2 to 100 carbon atoms). The above Rf 4 group is

[0220]

Chemical formula

[0221] (wherein, d3 is an integer of 1 to 4; e3 is an integer of 1 to 10), etc. may be mentioned.

[0222] As the above-mentioned other monomer, the formula (n2-2): CH 2 =CHO-Rf 5 (n2-2) (wherein, Rf 5 is a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having an ether bond and 2 to 100 carbon atoms) and fluorine-containing vinyl ethers represented thereby may also be mentioned.

[0223] Specific examples of the monomer of the general formula (n2-2) include

[0224]

Chemical formula

[0225] (wherein, e6 is an integer of 1 to 10), etc. are preferably mentioned.

[0226] More specifically,

[0227]

Chemical formula

[0228] etc. may be mentioned.

[0229] In addition, the general formula (n2-3): CH 2 =CHCH 2 O-Rf 6 (n2-3) (wherein, Rf 6 is a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having an ether bond and 2 to 100 carbon atoms) and fluorine-containing allyl ethers represented thereby, the general formula (n2-4): CH 2 =CH-Rf 7 (n2-4) (wherein, Rf 7Examples also include fluorine-containing vinyl monomers represented by a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having an ether bond with 2 to 100 carbon atoms).

[0230] Specific examples of the monomers represented by general formulas (n2-3) and (n2-4) include

[0231]

Chemical formula

[0232] and other monomers such as these.

[0233] The polymer (I) usually has end groups. The end groups are end groups generated during polymerization, and typical end groups are independently selected from hydrogen, iodine, bromine, linear or branched alkyl groups, and linear or branched fluoroalkyl groups, and may optionally additionally contain at least one chain heteroatom. The alkyl group or fluoroalkyl group preferably has 1 to 20 carbon atoms. These end groups are generally generated from initiators or chain transfer agents used in the formation of the polymer (I), or are generated during the chain transfer reaction.

[0234] In the polymer (I), the content of the polymerization unit (I) is, in descending order of preference, 1.0 mol% or more, 3.0 mol% or more, 5.0 mol% or more, 10 mol% or more, 20 mol% or more, 30 mol% or more, 40 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, 90 mol% or more, based on all the polymerization units. The content of the polymerization unit (I) is particularly preferably substantially 100 mol%, and most preferably the polymer (I) consists only of the polymerization unit (I).

[0235] In polymer (I), the content of polymerized units based on other monomers copolymerizable with the monomer represented by general formula (I) is preferably, in descending order, 99.0 mol% or less, 97.0 mol% or less, 95.0 mol% or less, 90 mol% or less, 80 mol% or less, 70 mol% or less, 60 mol% or less, 50 mol% or less, 40 mol% or less, 30 mol% or less, 20 mol% or less, 10 mol% or less, based on all the polymerized units. It is particularly preferable that the content of polymerized units based on other monomers copolymerizable with the monomer represented by general formula (I) is substantially 0 mol%, and most preferably, polymer (I) does not contain polymerized units based on other monomers.

[0236] The number average molecular weight of polymer (I) is preferably 0.1×10 4 or more, more preferably 0.2×10 4 or more, still more preferably 0.3×10 4 or more, even more preferably 0.4×10 4 or more, yet more preferably 0.5×10 4 or more, particularly preferably 1.0×10 4 or more, especially preferably 3.0×10 4 or more, most preferably 3.1×10 4 or more. Also, preferably 75.0×10 4 or less, more preferably 50.0×10 4 or less, still more preferably 40.0×10 4 or less, even more preferably 30.0×10 4 or less, yet more preferably 20.0×10 4 or less. The number average molecular weight and the weight average molecular weight are values calculated by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard. Also, when measurement by GPC is not possible, the number average molecular weight of polymer (I) can be determined from the correlation between the number average molecular weight calculated from the number of terminal groups obtained by NMR, FT-IR, etc. and the melt flow rate. The melt flow rate can be measured in accordance with JIS K 7210.

[0237] The lower limit of the weight average molecular weight of polymer (I) is preferably, in descending order, 0.2×104 Above, 0.4×10 4 Above, 0.6×10 4 Above, 0.8×10 4 Above, 1.0×10 4 Above, 2.0×10 4 Above, 5.0×10 4 Above, 10.0×10 4 Above, 15.0×10 4 Above, 20.0×10 4 Above, 25.0×10 4 The above. Further, as the upper limit of the weight average molecular weight of the polymer (I), in descending order of preference, 150.0×10 4 Below, 100.0×10 4 Below, 60.0×10 4 Below, 50.0×10 4 Below, 40.0×10 4 Below.

[0238] The polymer (I) preferably has an ion exchange rate (IXR) of 53 or less. The above IXR is defined as the number of carbon atoms in the polymer main chain relative to the ionic group. A precursor group that becomes ionic by hydrolysis (for example, -SO 2 F) is not regarded as an ionic group for the purpose of determining the IXR.

[0239] The IXR is preferably 0.5 or more, more preferably 1 or more, still more preferably 3 or more, even more preferably 4 or more, particularly preferably 5 or more, and especially preferably 8 or more. Also, the IXR is more preferably 43 or less, still more preferably 33 or less, and particularly preferably 23 or less.

[0240] As the ion exchange capacity of the polymer (I), in descending order of preference, 0.80 meq / g or more, 1.50 meq / g or more, 1.75 meq / g or more, 2.00 meq / g or more, 2.20 meq / g or more, more than 2.20 meq / g, 2.50 meq / g or more, 2.60 meq / g or more, 3.00 meq / g or more, 3.50 meq / g or more. The ion exchange capacity is the content of the ionic group (anionic group) of the polymer (I) and is determined by calculation from the composition of the polymer (I).

[0241] In polymer (I), the ionic group (anionic group) is typically distributed along the polymer main chain. The above polymer (I) includes the polymer main chain together with the repeating side chains bonded to this main chain, and it is preferable that this side chain has an ionic group.

[0242] Polymer (I) preferably contains an ionic group having a pKa of less than 10, more preferably less than 7. The ionic group of polymer (I) is preferably selected from the group consisting of sulfonate, carboxylate, phosphonate, and phosphate.

[0243] The terms "sulfonate, carboxylate, phosphonate, and phosphate" are intended to refer to the respective salts or the respective acids capable of forming salts. When a salt is used, preferably, the salt is an alkali metal salt or an ammonium salt. A preferred ionic group is a sulfonate group.

[0244] Polymer (I) preferably has water solubility. Water solubility means the property of being easily dissolved or dispersed in an aqueous medium. A water-soluble polymer (I) shows, for example, that the particle size cannot be measured by the dynamic light scattering method (DLS) or has a particle size of 10 nm or less.

[0245] The viscosity of the aqueous solution of polymer (I) is preferably 5.0 mPa·s or more, more preferably 8.0 mPa·s or more, still more preferably 10.0 mPa·s or more, particularly preferably 12.0 mPa·s or more, most preferably 14.0 mPa·s or more, preferably 100.0 mPa·s or less, more preferably 50.0 mPa·s or less, still more preferably 25.0 mPa·s or less, and particularly preferably 20.0 mPa·s or less.

[0246] The viscosity of the aqueous solution of polymer (I) can be specified by adjusting the content of polymer (I) in the aqueous solution to 33% by mass based on the aqueous solution and measuring the viscosity of the resulting aqueous solution at 20 °C using a tuning fork vibration viscometer (model number: SV-10) manufactured by A&D Company, Limited.

[0247] The critical micelle concentration (CMC) of polymer (I) is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, still more preferably 1% by mass or more, preferably 20% by mass or less, more preferably 10% by mass or less, and still more preferably 5% by mass or less.

[0248] The critical micelle concentration of polymer (I) can be determined by measuring the surface tension. The surface tension can be measured, for example, using a surface tensiometer CBVP-A3 type manufactured by Kyowa Interface Science Co., Ltd.

[0249] The acid value of polymer (I) is preferably 60 or more, more preferably 90 or more, still more preferably 120 or more, particularly preferably 150 or more, most preferably 180 or more, and the upper limit is not particularly limited, but is preferably 300 or less.

[0250] When polymer (I) has an anionic group other than an acid-type functional group, for example, -COOM, -SO 3 M, -OSO 3 M or -C(CF 3 ) 2 OM (where M is a metal atom, NR 7 4 , imidazolium which may have a substituent, pyridinium which may have a substituent, or phosphonium which may have a substituent, and R 7 is H or an organic group), it can be measured by acid-base titration after converting these groups to acid-type groups.

[0251] As the polymer (I), a polymer (11) of a monomer (11) represented by the general formula (11), wherein the content of the polymerization unit (11) based on the monomer (11) is 50 mol% or more with respect to all the polymerization units constituting the polymer (11), and the weight average molecular weight (Mw) is 38.0×10 4 or more can also be used. The polymer (11) is a novel polymer. General formula (11): CX 2 =CY-CF 2 -O-Rf-A (In the formula, X and Y are independently H, F, CH 3 or CF 3 , and at least one of X and Y is F. Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms, or a fluorine-containing alkylene group having an ether bond and having 2 to 100 carbon atoms. A is -COOM, -SO 3 M, -OSO 3 M or -C(CF 3 ) 2 OM (M is H, a metal atom, NR 7 4 , an imidazolium which may have a substituent, a pyridinium which may have a substituent or a phosphonium which may have a substituent, and R 7 is H or an organic group).)

[0252] In the general formula (11), X and Y are independently H, F, CH 3 or CF 3 , and at least one of X and Y is F. As X, H or F is preferable, and H is more preferable. As Y, H or F is preferable, and F is more preferable.

[0253] Regarding Rf and A in the general formula (11), they are the same as Rf and A in the general formula (1) representing the monomer constituting the polymer (1).

[0254] The polymer (11) may be a homopolymer consisting only of polymerization units (11) based on the monomer (11), or may be a copolymer containing the polymerization unit (11) and a polymerization unit based on another monomer copolymerizable with the monomer (11). The other monomer is as described above. The polymerization unit (11) may be the same or different in each occurrence, and the polymer (11) may contain polymerization units (11) based on monomers represented by two or more different general formulas (11).

[0255] Regarding the content of the polymerization unit (11) in the polymer (11), in descending order of preference, it is 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, 90 mol% or more, 99 mol% or more with respect to all the polymerization units constituting the polymer (11). It is particularly preferable that the content of the polymerization unit (11) is substantially 100 mol%, and it is most preferable that the polymer (11) consists only of the polymerization unit (11).

[0256] Regarding the content of the polymerization unit based on another monomer copolymerizable with the monomer (11) in the polymer (11), in descending order of preference, it is 99.0 mol% or less, 97.0 mol% or less, 95.0 mol% or less, 90 mol% or less, 80 mol% or less, 70 mol% or less, 60 mol% or less, 50 mol% or less with respect to all the polymerization units constituting the polymer (11). It is particularly preferable that the content of the polymerization unit based on another monomer copolymerizable with the monomer (11) is substantially 0 mol%, and it is most preferable that the polymer (11) does not contain a polymerization unit based on another monomer.

[0257] Regarding the lower limit of the weight-average molecular weight of the polymer (11), in descending order of preference, it is 38.0×10 4 or more, 40.0×10 4 or more. Regarding the upper limit of the weight-average molecular weight of the polymer (11), in descending order of preference, it is 150.0×10 4 or less, 100.0×10 4 or less, 60.0×10 4 or less.

[0258] Regarding the lower limit of the number-average molecular weight of the polymer (11), in descending order of preference, it is 5.0×104 , 8.0×10 4 , 10.0×10 4 or more, 12.0×10 4 or more. As the upper limit of the number average molecular weight of the polymer (11), in descending order of preference, 75.0×10 4 or less, 50.0×10 4 or less, 40.0×10 4 or less, 30.0×10 4 or less.

[0259] As the polymer (I), a polymer (12) of a monomer (12) represented by the general formula (12), wherein the content of the polymerization unit (12) based on the monomer (12) is 50 mol% or more with respect to all the polymerization units constituting the polymer (12), and the weight average molecular weight (Mw) is 1.4×10 4 or more can also be used. The polymer (12) is a novel polymer. General formula (12): CX 2 =CX - O - Rf - A (In the formula, X is independently F or CF 3 . Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms, or a fluorine-containing alkylene group having an ether bond or a keto group having 2 to 100 carbon atoms. A is -COOM, -SO 3 M, -OSO 3 M or -C(CF 3 ) 2 OM (M is -H, a metal atom, -NR 7 4 , an imidazolium which may have a substituent, a pyridinium which may have a substituent or a phosphonium which may have a substituent, and R 7 is H or an organic group).)

[0260] In the general formula (12), X is independently F or CF 3 . It is preferable that at least one or more of X is F, and it is more preferable that all of X are F.

[0261] Regarding Rf and A in the general formula (12), they are the same as Rf and A in the general formula (2) representing the monomer that constitutes the polymer (2).

[0262] The polymer (12) may be a homopolymer consisting only of the polymerization unit (12) based on the monomer (12), or it may be a copolymer containing the polymerization unit (12) and a polymerization unit based on another monomer copolymerizable with the monomer (12). Other monomers are as described above. The polymerization unit (12) may be the same or different at each occurrence, and the polymer (12) may contain polymerization units (12) based on two or more different monomers represented by the general formula (12).

[0263] As the content of the polymerization unit (12) in the polymer (12), in descending order of preference, it is 40 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, 90 mol% or more, 99 mol% or more with respect to all the polymerization units constituting the polymer (12). It is particularly preferable that the content of the polymerization unit (12) is substantially 100 mol%, and most preferably the polymer (12) consists only of the polymerization unit (12).

[0264] In the polymer (12), as the content of the polymerization unit based on another monomer copolymerizable with the monomer (12), in descending order of preference, it is 50 mol% or less, 40 mol% or less, 30 mol% or less, 20 mol% or less, 10 mol% or less, 1 mol% or less with respect to all the polymerization units constituting the polymer (12). It is particularly preferable that the content of the polymerization unit based on another monomer copolymerizable with the monomer (12) is substantially 0 mol%, and most preferably the polymer (12) does not contain a polymerization unit based on another monomer.

[0265] The lower limit of the weight average molecular weight (Mw) of the polymer (12) is, in descending order of preference, 1.4×10 4 or more, 1.7×10 4 or more, 1.9×10 4 or more, 2.1×10 4 or more, 2.3×10 4 or more, 2.7×10 4 or more, 3.1×104 3.5×10 or more 4 3.9×10 or more 4 4.3×10 or more 4 4.7×10 or more 4 5.1×10 or more 4 The upper limit of the weight average molecular weight (Mw) of the polymer (12) is preferably, in descending order, 150.0×10 4 or less, 100.0×10 4 or less, 60.0×10 4 or less, 50.0×10 4 or less, 40.0×10 4 or less.

[0266] The lower limit of the number average molecular weight (Mn) of the polymer (12) is preferably, in descending order, 0.7×10 4 or more, 0.9×10 4 or more, 1.0×10 4 or more, 1.2×10 4 or more, 1.4×10 4 or more, 1.6×10 4 or more, 1.8×10 4 or more. The upper limit of the number average molecular weight (Mn) of the polymer (12) is preferably, in descending order, 75.0×10 4 or less, 50.0×10 4 or less, 40.0×10 4 or less, 30.0×10 4 or less, 20.0×10 4 or less.

[0267] The molecular weight distribution (Mw / Mn) of the polymer (12) is preferably 3.0 or less, more preferably 2.4 or less, still more preferably 2.2 or less, particularly preferably 2.0 or less, and most preferably 1.9 or less.

[0268] When the polymer (12) contains a polymerization unit (12) and a polymerization unit based on another monomer copolymerizable with the monomer (12), the content of the polymerization unit (12) based on the monomer (12) is preferably 40 to 60 mol%, more preferably 45 to 55 mol%, based on all the polymerization units constituting the polymer (12), and the content of the polymerization unit based on the other monomer is preferably 60 to 40 mol%, more preferably 55 to 45 mol%, based on all the polymerization units constituting the polymer (12). Such a configuration is such that the polymerization unit based on another monomer copolymerizable with the monomer (12) has the general formula CFR=CR 2 It is particularly suitable when it is a polymerization unit (M) based on the monomer represented by.

[0269] When the polymer (12) contains a polymerization unit (12) and a polymerization unit based on another monomer copolymerizable with the monomer (12), the alternation ratio between the polymerization unit (12) and the polymerization unit based on another monomer copolymerizable with the monomer (12) is preferably 40% or more, more preferably 50% or more, still more preferably 60% or more, yet still more preferably 70% or more, particularly preferably 80% or more, and most preferably 90% or more. The alternation ratio may be, for example, 40 to 99%. Such a configuration is such that the polymerization unit based on another monomer copolymerizable with the monomer (12) has the general formula CFR=CR 2 It is particularly suitable when it is a polymerization unit (M) based on the monomer represented by.

[0270] The alternation ratio between the polymerization unit (12) and the polymerization unit based on another monomer copolymerizable with the monomer (12) in the polymer (12) is 19 It can be determined by 19F-NMR analysis of the polymer (12).

[0271] The polymer (I) can be produced by a conventionally known method except for using the above monomers.

[0272] As the polymer (I), a polymer (13) of a monomer (13) represented by the general formula (13) can also be used, wherein the content of the polymerization unit (13) based on the monomer (13) is 50% by mass or more with respect to all the polymerization units constituting the polymer (13). The polymer (13) is a novel polymer. General formula (13): CX 2 =CX - O - Rf - SO 3 M (In the formula, X is independently F or CF 3 and Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms, or a fluorine-containing alkylene group having an ether bond or a keto group and having 2 to 100 carbon atoms. M is -H, a metal atom, -NR 7 4 , an imidazolium which may have a substituent, a pyridinium which may have a substituent or a phosphonium which may have a substituent, and R 7 is H or an organic group.)

[0273] In the general formula (13), X is independently F or CF 3 and it is preferable that at least one or more of X is F, and it is more preferable that all of X are F.

[0274] Regarding Rf and M in the general formula (13), they are the same as Rf and A in the general formula (2) representing the monomer constituting the polymer (2).

[0275] The polymer (13) may be a homopolymer consisting only of the polymerization unit (13) based on the monomer (13), or may be a copolymer containing the polymerization unit (13) and a polymerization unit based on another monomer copolymerizable with the monomer (13). The other monomers are as described above. The polymerization unit (13) may be the same or different at each occurrence, and the polymer (13) may contain polymerization units (13) based on two or more different monomers represented by the general formula (13).

[0276] The content of the polymerization unit (13) based on the monomer (13) in the polymer (13) is 50% by mass or more with respect to all the polymerization units constituting the polymer (13). The content of the polymerization unit (13) in the polymer (13) is preferably, in descending order, 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, 99% by mass or more with respect to all the polymerization units constituting the polymer (13). It is particularly preferable that the content of the polymerization unit (13) is substantially 100% by mass, and most preferably the polymer (13) consists only of the polymerization unit (13).

[0277] In the polymer (13), the content of the polymerization unit based on another monomer copolymerizable with the monomer (13) is preferably, in descending order, 50% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less, 10% by mass or less, 1% by mass or less with respect to all the polymerization units constituting the polymer (13). It is particularly preferable that the content of the polymerization unit based on another monomer copolymerizable with the monomer (13) is substantially 0% by mass, and most preferably the polymer (13) does not contain the polymerization unit based on another monomer.

[0278] The lower limit of the number average molecular weight of the polymer (13) is preferably, in descending order, 0.3×10 4 or more, 0.4×10 4 or more, 0.5×10 4 or more, 0.7×10 4 or more, 0.8×10 4 or more, 1.0×10 4 or more, 1.2×10 4 or more, 1.4×10 4 , 1.6×10 4 or more, 1.8×10 4 or more, 2.0×10 4 or more, 3.0×10 4 or more. The upper limit of the number average molecular weight of the polymer (13) is preferably, in descending order, 75.0×10 4 or less, 50.0×10 4 or less, 40.0×10 4 or less, 30.0×10 4 or less, 20.0×10 4 or less.

[0279] The lower limit of the weight-average molecular weight of the polymer (13) is, in preferred order, 0.4×10 4 or more, 0.5×10 4 or more, 0.6×10 4 or more, 0.8×10 4 or more, 1.0×10 4 or more, 1.2×10 4 or more, 1.4×10 4 or more, 1.7×10 4 or more, 1.9×10 4 or more, 2.1×10 4 or more, 2.3×10 4 or more, 2.7×10 4 or more, 3.1×10 4 or more, 3.5×10 4 or more, 3.9×10 4 or more, 4.3×10 4 or more, 4.7×10 4 or more, 5.1×10 4 or more, 10.0×10 4 or more, 15.0×10 4 or more, 20.0×10 4 or more, 25.0×10 4 or more. The upper limit of the weight-average molecular weight of the polymer (13) is, in preferred order, 150.0×10 4 or less, 100.0×10 4 or less, 60.0×10 4 or less, 50.0×10 4 or less, 40.0×10 4 or less.

[0280] The molecular weight distribution (Mw / Mn) of the polymer (13) is, in preferred order, 3.0 or less, 2.4 or less, 2.2 or less, 2.0 or less, 1.9 or less, 1.7 or less, 1.5 or less, 1.4 or less, 1.3 or less.

[0281] Among the polymers (I), the polymer (11) is a novel polymer and can be produced by a production method (11) of producing the polymer (11) of the monomer (11) by polymerizing the monomer (11) represented by the general formula (11) in an aqueous medium, wherein the oxygen concentration in the reaction system of the polymerization is maintained at 500 volume ppm or less.

[0282] In the production method (11), the oxygen concentration in the polymerization reaction system is 500 ppm by volume or less. In the production method (11), the oxygen concentration in the reaction system is maintained at 500 ppm by volume or less throughout the entire polymerization period of the monomer (11). The oxygen concentration in the reaction system is preferably 350 ppm by volume or less, more preferably 300 ppm by volume or less, still more preferably 100 ppm by volume or less, and particularly preferably 50 ppm by volume or less. Also, the oxygen concentration in the reaction system is usually 0.01 ppm by volume or more.

[0283] In the production method (11), the polymerization temperature of the monomer (11) is preferably 59°C or lower, more preferably 57°C or lower, still more preferably 55°C or lower, particularly preferably 53°C or lower, preferably 20°C or higher, more preferably 25°C or higher, still more preferably 30°C or higher, and particularly preferably 35°C or higher, because a polymer (11) with a higher molecular weight can be easily produced.

[0284] In the production method (11), the monomer (11) may be copolymerized with the other monomers described above.

[0285] In the production method (11), the polymerization pressure is usually from atmospheric pressure to 10 MPaG. The polymerization pressure is appropriately determined according to the type of monomer used, the molecular weight of the target polymer, and the reaction rate.

[0286] In the production method (11), the polymerization time is usually 1 to 200 hours, and may be 5 to 100 hours.

[0287] Among the polymers (I), the polymer (12) is a novel polymer, and it is a production method of the polymer (12) for producing the polymer (12) of the monomer (12) by polymerizing the monomer (12) represented by the general formula (12) in an aqueous medium, and it can be produced by the production method (12) that maintains the oxygen concentration in the polymerization reaction system at 1500 ppm by volume or less.

[0288] In the production method (12), the oxygen concentration in the polymerization reaction system is 1500 ppm by volume or less. In the production method (12), the oxygen concentration in the reaction system is maintained at 1500 ppm by volume or less throughout the entire polymerization period of the monomer (12). The oxygen concentration in the reaction system is preferably 500 ppm by volume or less, more preferably 100 ppm by volume or less, still more preferably 50 ppm by volume or less. Also, the oxygen concentration in the reaction system is usually 0.01 ppm by volume or more.

[0289] Among the polymers (I), the polymer (13) is a novel polymer and can be produced by a production method (13) of the polymer (13) for producing the polymer (13) of the monomer (13) by polymerizing the monomer (13) represented by the general formula (13) in an aqueous medium.

[0290] In the production method (13), the oxygen concentration in the polymerization reaction system is preferably 1500 ppm by volume or less, more preferably 500 ppm by volume or less, still more preferably 100 ppm by volume or less, and particularly preferably 50 ppm by volume or less. Also, the oxygen concentration in the reaction system is usually 0.01 ppm by volume or more. In the above production method, it is preferable that the oxygen concentration in the reaction system be maintained within the above range throughout the entire polymerization period of the monomer (13).

[0291] In the production methods (12) and (13), the polymerization temperatures of the monomer (12) and the monomer (13) are preferably 70°C or lower, more preferably 65°C or lower, still more preferably 60°C or lower, particularly preferably 55°C or lower, extremely preferably 50°C or lower, especially preferably 45°C or lower, most preferably 40°C or lower, and preferably 10°C or higher, more preferably 15°C or higher, still more preferably 20°C or higher, because polymers (12) and (13) with even higher molecular weights can be easily produced.

[0292] In the production methods (12) and (13), the monomer (12) or monomer (13) may be copolymerized with the other monomers described above.

[0293] In the production methods (12) and (13), the polymerization pressure is usually from atmospheric pressure to 10 MPaG. The polymerization pressure is appropriately determined according to the type of monomer used, the molecular weight of the target polymer, and the reaction rate.

[0294] In the production methods (12) and (13), the polymerization time is usually from 1 to 200 hours, and may be from 5 to 100 hours.

[0295] In the production methods (11) to (13), the oxygen concentration in the polymerization reaction system can be controlled, for example, by using an inert gas such as nitrogen or argon, or, when using a gaseous monomer, by flowing the gaseous monomer through the liquid phase or gas phase in the reactor. The oxygen concentration in the polymerization reaction system can be determined by measuring and analyzing the gas coming out of the exhaust gas line of the polymerization system with a low-concentration oxygen analyzer.

[0296] In the production methods (11) to (13), the aqueous medium is a reaction medium for carrying out the polymerization and means a liquid containing water. The aqueous medium is not particularly limited as long as it contains water, and may contain water and, for example, a fluorine-free organic solvent such as alcohol, ether, or ketone, and / or a fluorine-containing organic solvent having a boiling point of 40°C or lower. Preferably, the aqueous medium is water.

[0297] In the production methods (11) to (13), the polymerization of the monomer can be carried out in the presence of a polymerization initiator. The polymerization initiator is not particularly limited as long as it can generate radicals in the above polymerization temperature range, and known oil-soluble and / or water-soluble polymerization initiators can be used. Furthermore, polymerization can also be initiated as a redox in combination with a reducing agent or the like. The concentration of the polymerization initiator is appropriately determined according to the type of monomer, the molecular weight of the target polymer, and the reaction rate.

[0298] As the polymerization initiator, persulfates (e.g., ammonium persulfate), and organic peroxides such as disuccinic peroxide and diglutaric peroxide can be used alone or in the form of mixtures thereof. Further, it may be used in a redox system in combination with a reducing agent such as sodium sulfite. Furthermore, during the polymerization, a radical scavenger such as hydroquinone or catechol can be added, or a peroxide decomposer such as ammonium sulfite can be added to adjust the radical concentration in the system.

[0299] As the polymerization initiator, persulfates are particularly preferred because they can easily produce polymers with even higher molecular weights. Examples of persulfates include ammonium persulfate, potassium persulfate, sodium persulfate, etc., and ammonium persulfate is preferred.

[0300] The addition amount of the polymerization initiator is not particularly limited, but it may be added all at once, sequentially, or continuously at the beginning of the polymerization in an amount such that the polymerization rate does not significantly decrease (for example, several ppm with respect to the water concentration) or more. The upper limit is in a range where the reaction temperature may be increased while removing the heat of polymerization reaction from the equipment surface, and a more preferable upper limit is in a range where the heat of polymerization reaction can be removed from the equipment surface.

[0301] In the production methods (11) to (13), the polymerization initiator can be added at the start of polymerization and also during the polymerization. The ratio of the addition amount of the polymerization initiator added at the start of polymerization to the addition amount of the polymerization initiator added during the polymerization is preferably 95 / 5 to 5 / 95, more preferably 60 / 40 to 10 / 90, and even more preferably 30 / 70 to 15 / 85. The addition method of the polymerization initiator added during the polymerization is not particularly limited, and the entire amount may be added at once, added in two or more divided portions, or added continuously.

[0302] In the production methods (11) to (13), since a polymer with an even higher molecular weight can be easily produced, the total addition amount of the polymerization initiator used in the polymerization is preferably 0.00001 to 10% by mass based on the aqueous medium. As the total addition amount of the polymerization initiator used in the polymerization, it is more preferably 0.0001% by mass or more, still more preferably 0.001% by mass or more, particularly preferably 0.01% by mass or more, more preferably 5% by mass or less, still more preferably 2% by mass or less.

[0303] In the production methods (11) to (13), since a polymer with an even higher molecular weight can be easily produced, the total addition amount of the polymerization initiator used in the polymerization is preferably 0.001 to 10 mol% based on the monomer. As the total addition amount of the polymerization initiator used in the polymerization, it is more preferably 0.005 mol% or more, still more preferably 0.01 mol% or more, particularly preferably 0.1 mol% or more, most preferably 0.5 mol% or more, more preferably 5 mol% or less, still more preferably 2.5 mol% or less, particularly preferably 2.2 mol% or less, and most preferably 2.0 mol% or less.

[0304] In the production methods (11) to (13), since a polymer with an even higher molecular weight can be easily produced, the abundance of the monomer containing monomers (11) to (13) at the start of the polymerization is preferably 30% by mass or more based on the abundance of the aqueous medium. The abundance of the monomer is more preferably 30% by mass or more, still more preferably 40% by mass or more. The upper limit of the abundance of the monomer is not particularly limited, but from the viewpoint of allowing the polymerization to proceed smoothly, it may be 200% by mass or less. The abundance of the monomer at the start of the polymerization refers to the total abundance of monomers (11) to (13) present in the reactor at the start of the polymerization, and, if present, other monomers.

[0305] In the production methods (11) to (13), the polymerization may be carried out in the presence of a pH adjuster. The pH adjuster may be added before the start of the polymerization or after the start of the polymerization.

[0306] As the pH adjuster, ammonia, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, ammonium carbonate, sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, sodium phosphate, potassium phosphate, sodium citrate, potassium citrate, ammonium citrate, sodium gluconate, potassium gluconate, ammonium gluconate, etc. can be used.

[0307] In the production methods (11) to (13), the polymerization of the monomers (11) to (13) can be carried out by charging an aqueous medium, any one of the monomers (11) to (13), and, if necessary, other monomers and, if necessary, other additives into a reactor, stirring the contents of the reactor, maintaining the reactor at a predetermined polymerization temperature, then adding a predetermined amount of a polymerization initiator, and starting the polymerization reaction. After the start of the polymerization reaction, monomers, a polymerization initiator, and other additives may be added according to the purpose.

[0308] In the production methods (11) to (13), the polymerization of the monomers can be carried out in the substantial absence of a fluorine-containing surfactant. In the present disclosure, "in the substantial absence of a fluorine-containing surfactant" means that the amount of the fluorine-containing surfactant relative to the aqueous medium is 10 mass ppm or less. The amount of the fluorine-containing surfactant relative to the aqueous medium is preferably 1 mass ppm or less, more preferably 100 mass ppb or less, still more preferably 10 mass ppb or less, and even more preferably 1 mass ppb or less.

[0309] The fluorine-containing surfactant will be described later in the explanation regarding the polymerization of fluoromonomers.

[0310] The content of the polymer (I) in the composition to be concentrated is preferably more than 0.20 mass% and preferably 5.0 mass% or less, more preferably 2.0 mass% or less, still more preferably 1.0 mass% or less, and particularly preferably 0.50 mass% or less with respect to the fluoropolymer.

[0311] The content of polymer (I) in the composition is determined by solid-state NMR measurement. In addition, the measurement methods of each polymer are described in WO 2014 / 099453, WO 2010 / 075497, WO 2010 / 075496, WO 2011 / 008381, WO 2009 / 055521, WO 1987 / 007619, JP-A-61-293476, WO 2010 / 075494, WO 2010 / 075359, WO 2012 / 082454, WO 2006 / 119224, WO 2013 / 085864, WO 2012 / 082707, WO 2012 / 082703, WO 2012 / 082451, WO 2006 / 135825, WO 2004 / 067588, WO 2009 / 068528, JP-A-2004-075978, JP-A-2001-226436, WO 1992 / 017635, WO 2014 / 069165, JP-A-11-181009, etc. As the measurement method of the content of polymer (I), the measurement methods of each polymer described therein can be used.

[0312] The content of the dimer and trimer of monomer (I) represented by the general formula (I) in the composition is preferably 1.0% by mass or less, more preferably 0.1% by mass or less, still more preferably 0.01% by mass or less, particularly preferably 0.001% by mass or less, and most preferably 0.0001% by mass or less with respect to polymer (I).

[0313] (Aqueous medium) The aqueous medium used in the production method of the present disclosure means a liquid containing water. The above aqueous medium is not particularly limited as long as it contains water, and may contain water and, for example, a fluorine-free organic solvent such as alcohol, ether, ketone, and / or a fluorine-containing organic solvent having a boiling point of 40°C or lower.

[0314] (Composition) In the production method of the present disclosure, the composition containing a fluoropolymer (excluding polymer (I)) can be produced, for example, by polymerizing a fluoromonomer in an aqueous medium in the presence of polymer (I) to obtain a polymerization dispersion containing polymer (I), a fluoropolymer, and an aqueous medium, and then mixing the polymerization dispersion, a nonionic surfactant, and a fluorine-free anionic surfactant.

[0315] As the fluoromonomer, those having at least one double bond are preferred. Examples of the fluoromonomer include tetrafluoroethylene [TFE], hexafluoropropylene [HFP], chlorotrifluoroethylene [CTFE], vinyl fluoride, vinylidene fluoride [VDF], trifluoroethylene, fluoroalkyl vinyl ether, fluoroalkyl ethylene, fluoroalkyl allyl ether, trifluoropropylene, pentafluoropropylene, trifluorobutene, tetrafluoroisobutene, hexafluoroisobutene, general formula (100): CHX 101 =CX 102 Rf 101 (wherein X 101 and X 102 are such that one is H and the other is F, and Rf 101 is a linear or branched fluoroalkyl group having 1 to 12 carbon atoms), a fluorinated vinyl heterocyclic compound, and at least one selected from the group consisting of monomers providing a crosslinking site is preferred.

[0316] Examples of the fluoroalkyl vinyl ether include general formula (110): CF 2 =CF-ORf 111 (wherein Rf 111 represents a perfluoro organic group.) a fluoromonomer represented by general formula (120): CF 2 =CF-OCH 2 -Rf 121 (wherein Rf 121is a fluoromonomer represented by a perfluoroalkyl group having 1 to 5 carbon atoms), General formula (130): CF 2 =CFOCF 2 ORf 131 (wherein, Rf 131 is a linear or branched perfluoroalkyl group having 1 to 6 carbon atoms, a cyclic perfluoroalkyl group having 5 to 6 carbon atoms, or a linear or branched perfluorooxyalkyl group having 2 to 6 carbon atoms containing 1 to 3 oxygen atoms.).) is a fluoromonomer represented by General formula (140): CF 2 =CFO(CF 2 CF(Y 141 )O) m (CF 2 ) n F (wherein, Y 141 represents a fluorine atom or a trifluoromethyl group. m is an integer of 1 to 4. n is an integer of 1 to 4.).) is a fluoromonomer represented by, and General formula (150): CF 2 =CF-O-(CF 2 CFY 151 -O) n -(CFY 152 ) m -A 151 (wherein, Y 151 represents a fluorine atom, a chlorine atom, -SO 2 F group or a perfluoroalkyl group. The perfluoroalkyl group may contain an etheric oxygen and -SO 2 F group. n represents an integer of 0 to 3. n Y 151 may be the same or different. Y 152 represents a fluorine atom, a chlorine atom or -SO 2 F group. m represents an integer of 1 to 5. m Y 152 may be the same or different. A 151 represents -SO 2 X 151 , -COZ 151 or -POZ 152 Z 153 represents. X 151is F, Cl, Br, I, -OR 151 or -NR 152 R 153 represents. Z 151 , Z 152 and Z 153 are the same or different and are -NR 154 R 155 or -OR 156 represents. R 151 , R 152 , R 153 , R 154 , R 155 and R 156 are the same or different and represent H, ammonium, an alkali metal, an alkyl group which may contain a fluorine atom, an aryl group, or a sulfonyl-containing group. The fluoromonomer represented by) is preferably at least one selected from the group consisting of

[0317] In the present disclosure, the above-mentioned "perfluoro organic group" means an organic group in which all hydrogen atoms bonded to carbon atoms are substituted with fluorine atoms. The above-mentioned perfluoro organic group may have an ether oxygen

[0318] Examples of the fluoromonomer represented by the general formula (110) include a fluoromonomer in which Rf 111 is a perfluoroalkyl group having 1 to 10 carbon atoms. The number of carbon atoms of the above-mentioned perfluoroalkyl group is preferably 1 to 5

[0319] Examples of the perfluoro organic group in the general formula (110) include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, a perfluorohexyl group, and the like Examples of the fluoromonomer represented by the general formula (110) further include those in which, in the above general formula (110), Rf 111 is a perfluoro(alkoxyalkyl) group having 4 to 9 carbon atoms, and those in which Rf 111 is the following formula:

[0320]

Chemical formula

[0321] (wherein m represents an integer of 0 or 1 to 4) and a group represented by the following formula:

[0322] CF 3 CF 2 CF 2 -(O-CF(CF 3 )-CF 2 ) n - (wherein n represents an integer of 1 to 4) and the like.

[0323] As the fluoromonomer represented by the general formula (110), among others, General formula (160): CF 2 =CF-ORf 161 (wherein Rf 161 represents a perfluoroalkyl group having 1 to 10 carbon atoms). The fluoromonomer represented by this is preferred. Rf 161 is preferably a perfluoroalkyl group having 1 to 5 carbon atoms.

[0324] The fluoroalkyl vinyl ether is preferably at least one selected from the group consisting of the fluoromonomers represented by the general formulas (160), (130), and (140).

[0325] As the fluoromonomer represented by the general formula (160), at least one selected from the group consisting of perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether), and perfluoro(propyl vinyl ether) is preferred, and at least one selected from the group consisting of perfluoro(methyl vinyl ether) and perfluoro(propyl vinyl ether) is more preferred.

[0326] As the fluoromonomer represented by the general formula (130), CF 2 =CFOCF 2 OCF 3, CF 2 = CFOCF 2 OCF 2 CF 3 , and, CF 2 = CFOCF 2 OCF 2 CF 2 OCF 3 It is preferably at least one selected from the group consisting of.

[0327] As the fluoromonomer represented by the general formula (140), CF 2 = CFOCF 2 CF(CF 3 )O(CF 2 ) 3 F, CF 2 = CFO(CF 2 CF(CF 3 )O) 2 (CF 2 ) 3 , and, CF 2 = CFO(CF 2 CF(CF 3 )O) 2 (CF 2 ) 2 It is preferably at least one selected from the group consisting of.

[0328] As the fluoromonomer represented by the general formula (150), CF 2 = CFOCF 2 CF 2 SO 2 F, CF 2 = CFOCF 2 CF(CF 3 )OCF 2 CF 2 SO 2 F, CF 2 = CFOCF 2 CF(CF 2 CF 2 SO 2 F)OCF 2 CF 2 SO 2 F and CF 2 = CFOCF 2 CF(SO 2 F) 2At least one selected from the group consisting of is preferred.

[0329] As the fluoromonomer represented by the general formula (100), Rf 101 is preferably a fluoromonomer in which Rf is a linear fluoroalkyl group, and Rf 101 is more preferably a fluoromonomer in which Rf is a linear perfluoroalkyl group. The number of carbon atoms of Rf 101 is preferably 1 to 6. As the fluoromonomer represented by the general formula (100), CH 2 =CFCF 3 , CH 2 =CFCF 2 CF 3 , CH 2 =CFCF 2 CF 2 CF 3 , CH 2 =CFCF 2 CF 2 CF 2 H, CH 2 =CFCF 2 CF 2 CF 2 CF 3 , CHF=CHCF 3 (E form), CHF=CHCF 3 (Z form), etc. may be mentioned. Among them, CH 2 =CFCF 3 represented by 2,3,3,3-tetrafluoropropylene is preferred.

[0330] As the fluoroalkyl ethylene, the fluoroalkyl ethylene represented by the general formula (170): CH 2 =CH-(CF 2 ) n -X 171 (wherein X 171 is H or F, and n is an integer of 3 to 10.) is preferred, CH 2 =CH-C 4 F 9 , and CH 2 =CH-C 6 F 13It is more preferable that it is at least one selected from the group consisting of.

[0331] Examples of the fluoroalkyl allyl ether include General formula (180): CF 2 =CF-CF 2 -ORf 111 (In the formula, Rf 111 represents a perfluoro organic group.) Fluoromonomers represented thereby are included.

[0332] Rf in general formula (180) 111 is the same as Rf in general formula (110). Rf 111 As, a perfluoroalkyl group having 1 to 10 carbon atoms or a perfluoroalkoxyalkyl group having 1 to 10 carbon atoms is preferable. Examples of the fluoroalkyl allyl ether represented by general formula (180) include CF 111 =CF-CF 2 =CF-CF 2 -O-CF 3 CF 2 =CF-CF 2 -O-C 2 F 5 CF 2 =CF-CF 2 -O-C 3 F 7 CF 2 =CF-CF 2 -O-C 4 F 9 At least one selected from the group consisting of is preferable, CF 2 =CF-CF 2 -O-C 2 F 5 CF 2 =CF-CF 2 -O-C 3 F 7 CF 2 =CF-CF 2 -O-C 4 F 9 At least one selected from the group consisting of is more preferable, CF 2 =CF-CF 2 -O-CF 2 CF2 CF 3 is more preferable.

[0333] Examples of the fluorinated vinyl heterocyclic compound include the general formula (230):

Chemical formula

[0334]

Chemical formula

[0335] Examples of the monomer that provides a crosslinking site include the general formula (180): CX 181 2 =CX 182 -R f 181 CHR 181 X 183 (In the formula, X 181 and X 182 are independently a hydrogen atom, a fluorine atom, or CH 3 , R f 181 is a fluoroalkylene group, a perfluoroalkylene group, a fluoro(poly)oxyalkylene group, or a perfluoro(poly)oxyalkylene group, R 181 is a hydrogen atom or CH 3 , X 183 is an iodine atom or a bromine atom.)) The fluoromonomer represented by the formula, the general formula (190): CX 191 2 =CX 192 -R f 191X 193 (wherein X 191 and X 192 are each independently a hydrogen atom, a fluorine atom or CH 3 , R f 191 is a fluoroalkylene group, a perfluoroalkylene group, a fluoropolyoxyalkylene group or a perfluoropolyoxyalkylene group, X 193 is an iodine atom or a bromine atom.) A fluoromonomer represented by, General formula (200): CF 2 =CFO(CF 2 CF(CF 3 )O) m (CF 2 ) n -X 201 (wherein m is an integer of 0 to 5, n is an integer of 1 to 3, X 201 is a cyano group, a carboxyl group, an alkoxycarbonyl group, an iodine atom, a bromine atom, or -CH 2 I. ) A fluoromonomer represented by, and, General formula (210): CH 2 =CFCF 2 O(CF(CF 3 )CF 2 O) m (CF(CF 3 )) n -X 211 (wherein m is an integer of 0 to 5, n is an integer of 1 to 3, X 211 is a cyano group, a carboxyl group, an alkoxycarbonyl group, an iodine atom, a bromine atom, or -CH 2 OH. ) A fluoromonomer represented by, and, General formula (220): CR 221 R 222 =CR 223 -Z 221 -CR 224 =CR 225 R 226 (wherein R 221 , R 222 , R 223 , R 224 , R 225 and R226 is, independently of one another, a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Z 221 is a linear or branched alkylene group having 1 to 18 carbon atoms, which may have an oxygen atom, a cycloalkylene group having 3 to 18 carbon atoms, an alkylene group or oxyalkylene group having 1 to 10 carbon atoms which is at least partially fluorinated, or -(Q) p -CF 2 O-(CF 2 CF 2 O) m (CF 2 O) n -CF 2 -(Q) p - (wherein Q is an alkylene group or an oxyalkylene group. p is 0 or 1. m / n is 0.2 to 5.) and is a (per)fluoropolyoxyalkylene group having a molecular weight of 500 to 10,000. The monomer represented by is preferably at least one selected from the group consisting of

[0336] X 183 and X 193 are preferably iodine atoms. R f 181 and R f 191 are preferably perfluoroalkylene groups having 1 to 5 carbon atoms. R 181 is preferably a hydrogen atom. X 201 is preferably a cyano group, an alkoxycarbonyl group, an iodine atom, a bromine atom, or -CH 2 I. X 211 is preferably a cyano group, an alkoxycarbonyl group, an iodine atom, a bromine atom, or -CH 2 OH.

[0337] As the monomer that provides a crosslinking site, CF 2 =CFOCF 2 CF(CF 3 )OCF 2 CF 2 CN, CF 2=CFOCF 2 CF(CF 3 )OCF 2 CF 2 COOH, CF 2 =CFOCF 2 CF(CF 3 )OCF 2 CF 2 CH 2 I, C.F. 2 =CFOCF 2 CF 2 CH 2 I, C.H. 2 =CFCF 2 OCF(CF 3 )CF 2 OCF(CF 3 )CN, CH 2 =CFCF 2 OCF(CF 3 )CF 2 OCF(CF 3 )COOH, CH 2 =CFCF 2 OCF(CF 3 )CF 2 OCF(CF 3 )CH 2 OH, CH 2 =CHCF 2 CF 2 I, C.H. 2 =CH(CF 2 ) 2 CH=CH 2 , C.H. 2 =CH(CF 2 ) 6 CH=CH 2 , and CF 2 =CFO(CF 2 ) 5 CN, and CF 2 =CFOCF 2 CF(CF 3 )OCF 2 CF 2 CN and CF 2 =CFOCF 2 CF 2 CH 2 It is more preferable that the compound is at least one selected from the group consisting of I.

[0338] In the above polymerization, the fluoromonomer and the fluorine-free monomer may be polymerized. Examples of the fluorine-free monomer include hydrocarbon monomers having reactivity with the fluoromonomer. Examples of the hydrocarbon monomer include alkenes such as ethylene, propylene, butylene, and isobutylene; alkyl vinyl ethers such as ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, isobutyl vinyl ether, and cyclohexyl vinyl ether; vinyl esters such as vinyl acetate, vinyl propionate, n-butyl vinyl acetate, isobutyl vinyl acetate, vinyl valerate, vinyl pivalate, vinyl caproate, vinyl caprylate, vinyl caprate, vinyl versatate, vinyl laurate, vinyl myristate, vinyl palmitate, vinyl stearate, vinyl benzoate, vinyl p-t-butylbenzoate, vinyl cyclohexanecarboxylate, vinyl monochloroacetate, vinyl adipate, vinyl acrylate, vinyl methacrylate, vinyl crotonate, vinyl sorbate, vinyl cinnamate, vinyl undecylenate, vinyl hydroxyacetate, vinyl hydroxypropionate, vinyl hydroxybutyrate, vinyl hydroxyvalerate, vinyl hydroxyisobutyrate, and vinyl hydroxycyclohexanecarboxylate; alkyl allyl ethers such as ethyl allyl ether, propyl allyl ether, butyl allyl ether, isobutyl allyl ether, and cyclohexyl allyl ether; alkyl allyl esters such as ethyl allyl ester, propyl allyl ester, butyl allyl ester, isobutyl allyl ester, and cyclohexyl allyl ester; (meth)acrylate esters such as methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, and vinyl methacrylate.

[0339] As the fluorine-free monomer, a functional group-containing hydrocarbon monomer (excluding the monomer that provides a crosslinking site) may also be used. Examples of the functional group-containing hydrocarbon monomer include hydroxyalkyl vinyl ethers such as hydroxyethyl vinyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinyl ether, hydroxyisobutyl vinyl ether, and hydroxycyclohexyl vinyl ether; fluorine-free monomers having a carboxyl group such as acrylic acid, methacrylic acid, itaconic acid, succinic acid, succinic anhydride, fumaric acid, fumaric anhydride, crotonic acid, maleic acid, maleic anhydride, and perfluorobutene acid; fluorine-free monomers having a sulfo group such as vinyl sulfonic acid; fluorine-free monomers having a glycidyl group such as glycidyl vinyl ether and glycidyl allyl ether; fluorine-free monomers having an amino group such as aminoalkyl vinyl ether and aminoalkyl allyl ether; fluorine-free monomers having an amide group such as (meth)acrylamide and methylolacrylamide; and fluorine-free monomers having a nitrile group such as acrylonitrile and methacrylonitrile.

[0340] In the above polymerization, by polymerizing one or more of the fluoromonomers, particles of a desired fluoropolymer can be obtained.

[0341] The addition amount of the polymer (I) in the above polymerization is preferably more than 0.02% by mass and 10% by mass or less, more preferably 1% by mass or less, based on the aqueous medium. By setting the addition amount of the polymer (I) within the above range, the polymerization of the fluoromonomer in the aqueous medium can proceed smoothly. The addition amount of the polymer (I) is the total addition amount of the polymer (I) added in the above polymerization.

[0342] In the above polymerization, the polymer (I) may be added all at once or continuously. Adding the polymer (I) continuously means, for example, adding the polymer (I) not all at once but over time and without interruption or in portions. In the above polymerization, an aqueous solution containing the polymer (I) and water may be prepared and added.

[0343] In the above polymerization, it is preferable to start adding the polymer (I) before the solid content of the fluoropolymer formed in the aqueous medium reaches 0.5% by mass, and then continue to add the polymer (I) continuously. The starting time for adding the polymer (I) is preferably before the solid content of the fluoropolymer reaches 0.3% by mass, more preferably before it reaches 0.2% by mass, still more preferably before it reaches 0.1% by mass, and particularly preferably simultaneously with the start of polymerization. The above solid content is the content of the fluoropolymer relative to the total of the aqueous medium and the fluoropolymer.

[0344] In the above polymerization, if at least one kind of the polymer (I) is used, it is possible to efficiently produce the fluoropolymer. Also, two or more kinds of the compounds included in the polymer (I) may be used simultaneously, or other compounds having surface activity other than the polymer (I) may be used simultaneously as long as they are volatile or may remain in a molded article made of a fluoropolymer or the like.

[0345] In the above polymerization, a nucleating agent may be used. The addition amount of the nucleating agent can be appropriately selected according to the type of the nucleating agent. The addition amount of the nucleating agent may be 5000 ppm by mass or less, preferably 1000 ppm by mass or less, more preferably 500 ppm by mass or less, still more preferably 100 ppm by mass or less, particularly preferably 50 ppm by mass or less, and most preferably 10 ppm by mass or less, based on the aqueous medium.

[0346] In the above polymerization, it is preferable to add a nucleating agent to the aqueous medium before the start of polymerization or before the solid content of the fluoropolymer formed in the aqueous medium reaches 5.0% by mass. By adding the nucleating agent at the initial stage of polymerization, an aqueous dispersion having a small average primary particle size and excellent stability can be obtained.

[0347] The amount of the nucleating agent added at the initial stage of polymerization is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, still more preferably 0.05% by mass or more, and particularly preferably 0.1% by mass or more, based on the resulting fluoropolymer. The upper limit of the amount of the nucleating agent added at the initial stage of polymerization is not limited, but is, for example, 2000% by mass.

[0348] By using a nucleating agent, a fluoropolymer having a small primary particle size can be obtained as compared with performing polymerization in the absence of the above nucleating agent.

[0349] Examples of the above nucleating agent include dicarboxylic acids, perfluoropolyether (PFPE) acids or their salts, and hydrocarbon-containing surfactants. The above nucleating agent preferably does not contain an aromatic ring and is preferably an aliphatic compound.

[0350] The above nucleating agent is preferably added before the addition of the polymerization initiator or simultaneously with the addition of the polymerization initiator, but the particle size distribution can also be adjusted by adding it during the polymerization.

[0351] The preferred amount of the above dicarboxylic acid is 1000 ppm by mass or less, more preferably 500 ppm by mass or less, and still more preferably 100 ppm by mass or less, based on the above aqueous medium.

[0352] The above-mentioned perfluoropolyether (PFPE) acid or its salt may have any chain structure in which oxygen atoms in the main chain of the molecule are separated by saturated fluorocarbon groups having 1 to 3 carbon atoms. Also, two or more types of fluorocarbon groups may be present in the molecule. Representative structures have repeating units represented by the following formula: (-CFCF 3 -CF 2 -O-) n (VII) (-CF 2 -CF 2 -CF 2 -O-) n (VIII) (-CF 2 -CF 2 -O-) n -(-CF 2 -O-) m (IX) (-CF 2 -CFCF 3 -O-)n-(-CF 2 -O-) m (X)

[0353] These structures are described by Kasai in J. Appl. Polymer Sci. 57, 797 (1995). As disclosed in this reference, the PFPE acid or its salt may have a carboxylic acid group or its salt at one or both ends. The PFPE acid or its salt may also have a sulfonic acid, phosphonic acid group or their salts at one or both ends. Further, the PFPE acid or its salt may have different groups at each end. For monofunctional PFPE, the other end of the molecule is usually perfluorinated, but may contain hydrogen or chlorine atoms. The PFPE acid or its salt has at least two ether oxygens, preferably at least four ether oxygens, and even more preferably at least six ether oxygens. Preferably, at least one of the fluorocarbon groups separating the ether oxygens, more preferably at least two of such fluorocarbon groups, has two or three carbon atoms. Even more preferably, at least 50% of the fluorocarbon groups separating the ether oxygens have two or three carbon atoms. Also preferably, the PFPE acid or its salt has a total of at least 15 carbon atoms. For example, the preferred minimum value of n or n + m in the repeating unit structure described above is at least 5. Two or more of the above PFPE acids or their salts having an acid group at one or both ends can be used in the production method of the present disclosure. The PFPE acid or its salt preferably has a number average molecular weight of less than 6000 g / mol.

[0354] The addition amount of the hydrocarbon-containing surfactant is preferably 40 mass ppm or less, more preferably 30 mass ppm or less, and still more preferably 20 mass ppm or less with respect to the aqueous medium. The ppm amount of the lipophilic nucleus formation sites present in the aqueous medium is presumed to be less than the addition amount. Therefore, the amount of the lipophilic nucleus formation sites is smaller than 40 mass ppm, 30 mass ppm, and 20 mass ppm, respectively. Since the lipophilic nucleus formation sites are considered to exist as molecules, even a very small amount of the hydrocarbon-containing surfactant can generate a large amount of lipophilic nucleus formation sites. Therefore, even by adding about 1 mass ppm of the hydrocarbon-containing surfactant to the aqueous medium, a beneficial effect can be obtained. The preferable lower limit is 0.01 mass ppm.

[0355] The hydrocarbon-containing surfactant includes nonionic surfactants and cationic surfactants including siloxane surfactants such as those disclosed in U.S. Patent No. 7,897,682 (Brothers et al.) and U.S. Patent No. 7,977,438 (Brothers et al.).

[0356] As the hydrocarbon-containing surfactant, a nonionic surfactant (for example, a nonionic hydrocarbon surfactant) is preferable. That is, as the nucleating agent, a nonionic surfactant is preferable. The nonionic surfactant preferably does not contain an aromatic moiety.

[0357] Examples of the nonionic surfactant include nonionic surfactants that can be contained in the composition to be concentrated.

[0358] In the above polymerization, a compound having a functional group capable of reacting by radical polymerization and a hydrophilic group may be used together with the polymer (I). As the compound having a functional group capable of reacting by radical polymerization and a hydrophilic group, the same compound as the modified monomer (A) described later can be used.

[0359] In the above polymerization, in addition to the polymer (I) and other compounds having surface activity used as desired, additives can be used to stabilize each compound. Examples of the above additives include buffers, pH adjusters, stabilization aids, dispersion stabilizers, and the like.

[0360] As the stabilization aid, paraffin wax, fluorinated oil, fluorinated solvent, silicone oil and the like are preferable. The stabilization aid may be used alone or in combination of two or more. As the stabilization aid, paraffin wax is more preferable. The paraffin wax may be liquid, semi-solid or solid at room temperature, but saturated hydrocarbons having 12 or more carbon atoms are preferable. The melting point of the paraffin wax is usually preferably 40 to 65°C, more preferably 50 to 65°C.

[0361] The amount of the stabilization aid used is preferably 0.1 to 12% by mass, more preferably 0.1 to 8% by mass based on the mass of the aqueous medium used. It is desirable that the stabilization aid is sufficiently hydrophobic and is completely separated from the aqueous dispersion after polymerization and does not become a contaminant component.

[0362] The above polymerization is carried out by charging an aqueous medium, the above polymer (I), a monomer and, if necessary, other additives into a polymerization reactor, stirring the contents of the reactor, maintaining the reactor at a predetermined polymerization temperature, then adding a predetermined amount of a polymerization initiator, and starting the polymerization reaction. After the start of the polymerization reaction, monomers, polymerization initiators, chain transfer agents, polymer (I), etc. may be additionally added according to the purpose. The polymer (I) may be added after the start of the polymerization reaction.

[0363] Usually, the polymerization temperature is 5 to 120°C and the polymerization pressure is 0.05 to 10 MPaG. The polymerization temperature and polymerization pressure are appropriately determined depending on the type of monomer used, the molecular weight of the target fluoropolymer, and the reaction rate.

[0364] The polymerization initiator is not particularly limited as long as it can generate radicals within the above polymerization temperature range, and known oil-soluble and / or water-soluble polymerization initiators can be used. Furthermore, polymerization can also be initiated as a redox system in combination with a reducing agent or the like. The concentration of the polymerization initiator is appropriately determined depending on the type of monomer, the molecular weight of the target fluoropolymer, and the reaction rate.

[0365] As the polymerization initiator, an oil-soluble radical polymerization initiator or a water-soluble radical polymerization initiator can be used.

[0366] The oil-soluble radical polymerization initiator may be a known oil-soluble peroxide, such as dialkyl peroxydicarbonates such as diisopropyl peroxydicarbonate and di-sec-butyl peroxydicarbonate, peroxy esters such as t-butyl peroxyisobutyrate and t-butyl peroxypivalate, and dialkyl peroxides such as di-t-butyl peroxide. Also, di(ω-hydroxy-dodecafluorocaproyl) peroxide, di(ω-hydroxy-tetradecafluoroheptanoyl) peroxide, di(ω-hydroxy-hexadecafluorononanoyl) peroxide, di(perfluorobutyryl) peroxide, di(perfluorovaleryl) peroxide, di(perfluorohexanoyl) peroxide, di(perfluoroheptanoyl) peroxide, di(perfluorooctanoyl) peroxide, di(perfluorononanoyl) peroxide, di(ω-chloro-hexafluorobutyryl) peroxide, di(ω-chloro-decafluorohexanoyl) peroxide, di(ω-chloro-tetradecafluorooctanoyl) peroxide, ω-hydroxy-dodecafluoroheptanoyl-ω-hydroxy-hexadecafluorononanoyl-peroxide, ω-chloro-hexafluorobutyryl-ω-chloro-decafluorohexanoyl-peroxide, ω-hydroxy-dodecafluoroheptanoyl-perfluorobutyryl-peroxide, di(dichloropentafluorobutanoyl) peroxide, di(trichlorooctafluorohexanoyl) peroxide, di(tetrachloroundecafluorooctanoyl) peroxide, di(pentachlorotetradecafluorodecanoyl) peroxide, di(undecachlorodotriacontapentafluorodocosanoyl) peroxide, and other di[perfluoro(or fluorochloro)acyl] peroxides are mentioned as typical ones.

[0367] The water-soluble radical polymerization initiator may be a known water-soluble peroxide. For example, ammonium salts, potassium salts, sodium salts of persulfuric acid, perboric acid, perchloric acid, phosphoric acid, percarbonic acid, etc., organic peroxides such as disuccinic peroxide, diglutaric peroxide, t-butyl permaleate, t-butyl hydroperoxide, etc. can be mentioned. A reducing agent such as sulfites may also be included, and the usage amount may be 0.1 to 20 times that of the peroxide.

[0368] For example, when polymerization is carried out at a low temperature of 30 °C or lower, it is preferable to use a redox initiator that combines an oxidizing agent and a reducing agent as the polymerization initiator. Examples of the oxidizing agent include persulfates, organic peroxides, potassium permanganate, manganese triacetate, ammonium cerium nitrate, etc. Examples of the reducing agent include sulfites, bisulfites, bromates, diimines, oxalic acid, etc. Examples of the persulfate include ammonium persulfate and potassium persulfate. Examples of the sulfite include sodium sulfite and ammonium sulfite. In order to increase the decomposition rate of the initiator, it is also preferable to add a copper salt or an iron salt to the combination of the redox initiator. Examples of the copper salt include copper(II) sulfate, and examples of the iron salt include iron(II) sulfate.

[0369] Examples of the above redox initiator include potassium permanganate / oxalic acid, ammonium persulfate / bisulfite / iron sulfate, manganese triacetate / oxalic acid, ammonium cerium nitrate / oxalic acid, bromate / bisulfite, etc., and potassium permanganate / oxalic acid is preferable. When using a redox initiator, either the oxidizing agent or the reducing agent may be charged into the polymerization tank in advance, and then the other may be added continuously or intermittently to initiate the polymerization. For example, when using potassium permanganate / oxalic acid, it is preferable to charge oxalic acid into the polymerization tank and continuously add potassium permanganate thereto.

[0370] The addition amount of the polymerization initiator is not particularly limited, but it may be added all at once, sequentially, or continuously at the beginning of the polymerization in an amount such that the polymerization rate does not significantly decrease (for example, several ppm relative to the water concentration) or more. The upper limit is in the range where the reaction temperature may be increased while removing the heat of polymerization reaction from the equipment surface, and a more preferable upper limit is in the range where the heat of polymerization reaction can be removed from the equipment surface.

[0371] The above aqueous medium is a reaction medium for carrying out polymerization and means a liquid containing water. The above aqueous medium is not particularly limited as long as it contains water, and may contain water and, for example, a fluorine-free organic solvent such as alcohol, ether, ketone, etc., and / or a fluorine-containing organic solvent having a boiling point of 40°C or lower.

[0372] In the above polymerization, furthermore, according to the purpose, a known chain transfer agent, radical scavenger, and decomposer can be added to adjust the polymerization rate and molecular weight.

[0373] Examples of the above chain transfer agent include esters such as dimethyl malonate, diethyl malonate, methyl acetate, ethyl acetate, butyl acetate, and dimethyl succinate, as well as isopentane, methane, ethane, propane, methanol, isopropanol, acetone, various mercaptans, various halogenated hydrocarbons such as carbon tetrachloride, and cyclohexane.

[0374] A bromine compound or iodine compound may be used as the chain transfer agent. Examples of the polymerization method using a bromine compound or iodine compound include, for example, a method of polymerizing a fluoromonomer in an aqueous medium in the presence of a bromine compound or iodine compound in a substantially oxygen-free state (iodine transfer polymerization method). Representative examples of the bromine compound or iodine compound to be used include, for example, the general formula: R a I x Br y (wherein x and y are each an integer from 0 to 2 and satisfy 1 ≦ x + y ≦ 2, and R ais a saturated or unsaturated fluorohydrocarbon group or chlorofluorohydrocarbon group having 1 to 16 carbon atoms, or a hydrocarbon group having 1 to 3 carbon atoms, which may contain an oxygen atom). Examples of the compound represented thereby include. By using a bromine compound or an iodine compound, iodine or bromine is introduced into the polymer and functions as a crosslinking point.

[0375] Examples of the bromine compound or iodine compound include, for example, 1,3-diiodoperfluoropropane, 2-iodoperfluoropropane, 1,3-diiodo-2-chloroperfluoropropane, 1,4-diiodoperfluorobutane, 1,5-diiodo-2,4-dichloroperfluoropentane, 1,6-diiodoperfluorhexane, 1,8-diiodoperfluorooctane, 1,12-diiodoperfluorododecane, 1,16-diiodoperfluorohexadecane, diiodomethane, 1,2-diiodoethane, 1,3-diiodo-n-propane, CF 2 Br 2 , BrCF 2 CF 2 Br, CF 3 CFBrCF 2 Br, CFClBr 2 , BrCF 2 CFClBr, CFBrClCFClBr, BrCF 2 CF 2 CF 2 Br, BrCF 2 CFBrOCF 3 , 1-bromo-2-iodoperfluoroethane, 1-bromo-3-iodoperfluoropropane, 1-bromo-4-iodoperfluorobutane, 2-bromo-3-iodoperfluorobutane, 3-bromo-4-iodoperfluorobutene-1, 2-bromo-4-iodoperfluorobutene-1, monoiodomonobromo substitution products of benzene, diiodomonobromo substitution products, and (2-iodoethyl) and (2-bromoethyl) substitution products, etc. are mentioned. These compounds may be used alone or in combination with each other.

[0376] Among these, from the viewpoints of polymerization reactivity, crosslinking reactivity, availability, etc., it is preferable to use 1,4-diiodoperfluorobutane, 1,6-diiodoperfluorohexane, or 2-iodoperfluoropropane.

[0377] The amount of the chain transfer agent used is usually 1 to 50,000 mass ppm, preferably 1 to 20,000 mass ppm, based on the total amount of the supplied fluoromonomer.

[0378] The above chain transfer agent may be added to the reaction vessel all at once before the start of polymerization, or may be added all at once after the start of polymerization, or may be added in a plurality of portions during polymerization, or may be continuously added during polymerization.

[0379] As the polymerization initiator, persulfates (for example, ammonium persulfate) or organic peroxides such as disuccinic peroxide and diglutaric peroxide can be used alone or in the form of a mixture thereof. Further, it may be used in a redox system in combination with a reducing agent such as sodium sulfite. Furthermore, during polymerization, a radical scavenger such as hydroquinone or catechol may be added, or a peroxide decomposer such as ammonium sulfite may be added to adjust the radical concentration in the system.

[0380] In the above polymerization, in the presence of the polymer (I), a fluoromonomer is polymerized in an aqueous medium to produce an aqueous dispersion of fluoropolymer particles, and in the aqueous dispersion of the above fluoropolymer particles, the fluoromonomer may be seed polymerized onto the fluoropolymer particles to obtain a fluoropolymer.

[0381] The above polymerization is preferably carried out by polymerizing a fluoromonomer substantially in the absence of a fluorine-containing surfactant (excluding compounds having a functional group capable of reacting by radical polymerization and a hydrophilic group). Conventionally, a fluorine-containing surfactant has been used for the polymerization of a fluoromonomer in an aqueous medium, but according to the production method of the present disclosure, a fluoropolymer can be obtained even when a fluorine-containing surfactant is not used.

[0382] In the present disclosure, "in the substantial absence of a fluorosurfactant" means that the amount of the fluorosurfactant in the aqueous medium is 10 ppm by mass or less. The amount of the fluorosurfactant in the aqueous medium is preferably 1 ppm by mass or less, more preferably 100 ppb by mass or less, still more preferably 10 ppb by mass or less, and even more preferably 1 ppb by mass or less.

[0383] Examples of the fluorosurfactant include anionic fluorosurfactants. The anionic fluorosurfactant may be, for example, a surfactant containing fluorine atoms and having a total carbon number of 20 or less in the portion excluding the anionic group.

[0384] The fluorosurfactant may also be a surfactant containing fluorine and having a molecular weight of the anionic moiety of 800 or less. Note that the "anionic moiety" means the portion excluding the cation of the fluorosurfactant. For example, in the case of F(CF 2 ) n1 COOM represented by the following formula (I) later, it is the portion of "F(CF 2 ) n1 COO".

[0385] Examples of the fluorosurfactant also include fluorosurfactants having a LogPOW of 3.5 or less. The LogPOW is the partition coefficient between 1-octanol and water, and is represented by LogP [where P represents the ratio of the concentration of the fluorosurfactant in octanol to the concentration of the fluorosurfactant in water when an octanol / water (1:1) mixture containing the fluorosurfactant is phase-separated]. The LogPOW is measured using a column: TOSOH ODS-120T column (φ4.6 mm × 250 mm, manufactured by Tosoh Corporation), and an eluent: acetonitrile / 0.6 mass% HClO 4Under the conditions of water = 1 / 1 (vol / vol%), flow rate: 1.0 ml / min, sample amount: 300 μL, column temperature: 40 °C, and detection light: UV 210 nm, HPLC was performed on standard substances (heptanoic acid, octanoic acid, nonanoic acid, and decanoic acid) having a known octanol / water partition coefficient, a calibration curve of each elution time and the known octanol / water partition coefficient was created, and based on this calibration curve, it was calculated from the elution time of HPLC in the sample solution.

[0386] Specific examples of the fluorine-containing surfactant include those described in U.S. Patent Application Publication No. 2007 / 0015864, U.S. Patent Application Publication No. 2007 / 0015865, U.S. Patent Application Publication No. 2007 / 0015866, U.S. Patent Application Publication No. 2007 / 0276103, U.S. Patent Application Publication No. 2007 / 0117914, U.S. Patent Application Publication No. 2007 / 142541, U.S. Patent Application Publication No. 2008 / 0015319, U.S. Patent No. 3250808, U.S. Patent No. 3271341, JP-A-2003-119204, WO 2005 / 042593, WO 2008 / 060461, WO 2007 / 046377, JP-A-2007-119526, WO 2007 / 046482, WO 2007 / 046345, U.S. Patent Application Publication No. 2014 / 0228531, WO 2013 / 189824, WO 2013 / 189826, etc.

[0387] As the anionic fluorine-containing surfactant, the following general formula (N 0 ): X n0 -Rf n0 -Y 0 (N 0 ) (In the formula, X n0 is H, Cl or and F. Rf n0 is an alkylene group having 3 to 20 carbon atoms, linear, branched or cyclic, in which part or all of the H is substituted by F, and the alkylene group may contain one or more ether bonds, and part of the H may be substituted by Cl. Y 0is an anionic group. Compounds represented by ) are exemplified. Y 0 The anionic group of is -COOM, -SO 2 M, or -SO 3 M, and may be -COOM, or -SO 3 M. M is H, a metal atom, NR 7 4 , imidazolium which may have a substituent, pyridinium which may have a substituent or phosphonium which may have a substituent, and R 7 is H or an organic group. Examples of the above metal atom include alkali metals (Group 1), alkaline earth metals (Group 2), etc., and for example, Na, K or Li. R 7 as may be H or a C 1-10 organic group, may be H or a C 1-4 organic group, may be H or a C 1-4 alkyl group. M may be H, a metal atom or NR 7 4 , and may be H, an alkali metal (Group 1), an alkaline earth metal (Group 2) or NR 7 4 , and may be H, Na, K, Li or NH 4 . The above Rf n0 may be one in which 50% or more of H is substituted with fluorine.

[0388] Examples of the compound represented by the above general formula (N 0 ) include the following general formula (N 1 ): X n0 -(CF 2 ) m1 -Y 0 (N 1 ) (In the formula, X n0 is H, Cl and F, m1 is an integer of 3 to 15, and Y 0 is as defined above.) Compounds represented by, the following general formula (N 2): Rf n1 -O-(CF(CF 3 )CF 2 O) m2 CFX n1 -Y 0 (N 2 ) (wherein, Rf n1 is a perfluoroalkyl group having 1 to 5 carbon atoms, m2 is an integer of 0 to 3, X n1 is F or CF 3 , and Y 0 is as defined above.) A compound represented by the following general formula (N 3 ): Rf n2 (CH 2 ) m3 -(Rf n3 ) q -Y 0 (N 3 ) (wherein, Rf n2 is a partially or fully fluorinated alkyl group which may contain an ether bond having 1 to 13 carbon atoms, m3 is an integer of 1 to 3, Rf n3 is a linear or branched perfluoroalkylene group having 1 to 3 carbon atoms, q is 0 or 1, and Y 0 is as defined above.) A compound represented by the following general formula (N 4 ): Rf n4 -O-(CY n1 Y n2 ) p CF 2 -Y 0 (N 4 ) (wherein, Rf n4 is a linear or branched partially or fully fluorinated alkyl group which may contain an ether bond and / or a chlorine atom having 1 to 12 carbon atoms, Y n1 and Y n2 are the same or different and are H or F, p is 0 or 1, and Y 0 is as defined above.) A compound represented by the formula, and the general formula (N 5 ):

Chemical Formula

[0389] More specifically, as the compound represented by the above general formula (N 0 ), there are a perfluorocarboxylic acid (I) represented by the following general formula (I), an ω-H perfluorocarboxylic acid (II) represented by the following general formula (II), a perfluoroether carboxylic acid (III) represented by the following general formula (III), a perfluoroalkylalkylene carboxylic acid (IV) represented by the following general formula (IV), a perfluoroalkoxyfluorocarboxylic acid (V) represented by the following general formula (V), a perfluoroalkylsulfonic acid (VI) represented by the following general formula (VI), an ω-H perfluorosulfonic acid (VII) represented by the following general formula (VII), a perfluoroalkylalkylene sulfonic acid (VIII) represented by the following general formula (VIII), an alkylalkylene carboxylic acid (IX) represented by the following general formula (IX), a fluorocarboxylic acid (X) represented by the following general formula (X), an alkoxyfluorosulfonic acid (XI) represented by the following general formula (XI), a compound (XII) represented by the following general formula (XII), a compound (XIII) represented by the following general formula (XIII), etc.

[0390] The above perfluorocarboxylic acid (I) is represented by the following general formula (I) F(CF 2 ) n1 COOM (I) (wherein, n1 is an integer of 3 to 14, and M is H, a metal atom, NR 7 4 , imidazolium which may have a substituent, pyridinium which may have a substituent, or phosphonium which may have a substituent, and R 7 is H or an organic group.) It is represented by.

[0391] The above ω-H perfluorocarboxylic acid (II) is represented by the following general formula (II) H(CF 2 ) n2 COOM (II) (wherein, n2 is an integer of 4 to 15, and M is as defined above.) It is represented by.

[0392] The above perfluoroether carboxylic acid (III) is represented by the following general formula (III) Rf 1 -O-(CF(CF 3 )CF 2 O) n3 CF(CF 3 )COOM (III) (wherein, Rf 1 is a perfluoroalkyl group having 1 to 5 carbon atoms, n3 is an integer of 0 to 3, and M is as defined above.) It is represented by.

[0393] The above perfluoroalkyl alkylene carboxylic acid (IV) is represented by the following general formula (IV) Rf 2 (CH 2 ) n4 Rf 3 COOM (IV) (wherein, Rf 2 is a perfluoroalkyl group having 1 to 5 carbon atoms, Rf 3 is a linear or branched perfluoroalkylene group having 1 to 3 carbon atoms, n4 is an integer of 1 to 3, and M is as defined above.) It is represented by.

[0394] The above alkoxyfluorocarboxylic acid (V) is represented by the following general formula (V) Rf 4 -O-CY 1 Y 2 CF 2 -COOM (V) (wherein, Rf 4 is a linear or branched or fully fluorinated alkyl group which may contain an ether bond having 1 to 12 carbon atoms and / or a chlorine atom, Y 1 and Y 2 are the same or different and are H or F, and M is as defined above.) is represented by the formula.

[0395] The above perfluoroalkylsulfonic acid (VI) is represented by the following general formula (VI) F(CF 2 ) n5 SO 3 M (VI) (wherein, n5 is an integer of 3 to 14, and M is as defined above.) is represented by the formula.

[0396] The above ω-H perfluorosulfonic acid (VII) is represented by the following general formula (VII) H(CF 2 ) n6 SO 3 M (VII) (wherein, n6 is an integer of 4 to 14, and M is as defined above.) is represented by the formula.

[0397] The above perfluoroalkylalkylene sulfonic acid (VIII) is represented by the following general formula (VIII) Rf 5 (CH 2 ) n7 SO 3 M (VIII) (wherein, Rf 5 is a perfluoroalkyl group having 1 to 13 carbon atoms, n7 is an integer of 1 to 3, and M is as defined above.) is represented by the formula.

[0398] The above alkylalkylene carboxylic acid (IX) is represented by the following general formula (IX) Rf6 (CH 2 ) n8 COOM (IX) (wherein, Rf 6 is a linear or branched or fully fluorinated alkyl group which may contain an ether bond having 1 to 13 carbon atoms, n8 is an integer of 1 to 3, and M is as defined above.) It is represented by.

[0399] The above fluorocarboxylic acid (X) has the following general formula (X) Rf 7 -O-Rf 8 -O-CF 2 -COOM (X) (wherein, Rf 7 is a linear or branched or fully fluorinated alkyl group which may contain an ether bond and / or a chlorine atom having 1 to 6 carbon atoms, Rf 8 is a linear or branched or fully fluorinated alkyl group having 1 to 6 carbon atoms, and M is as defined above.) It is represented by.

[0400] The above alkoxyfluorosulfonic acid (XI) has the following general formula (XI) Rf 9 -O-CY 1 Y 2 CF 2 -SO 3 M (XI) (wherein, Rf 9 is a linear or branched which may contain an ether bond having 1 to 12 carbon atoms, and may contain chlorine, a partially or fully fluorinated alkyl group, Y 1 and Y 2 are the same or different and are H or F, and M is as defined above.) It is represented by.

[0401] The above compound (XII) has the following general formula (XII):

Chemical formula

[0402] The above compound (XIII) has the following general formula (XIII): Rf 11 -O-(CF 2 CF(CF 3 )O) n9 (CF 2 O) n10 CF 2 COOM (XIII) (wherein Rf 11 is a fluoroalkyl group having 1 to 5 carbon atoms containing chlorine, n9 is an integer of 0 to 3, n10 is an integer of 0 to 3, and M is as defined above). It is represented by. Examples of compound (XIII) include CF 2 ClO(CF 2 CF(CF 3 )O) n9 (CF 2 O) n10 CF 2 COONH 4 (a mixture having an average molecular weight of 750, wherein n9 and n10 are as defined above).

[0403] As described above, examples of the anionic fluorine-containing surfactant include carboxylic acid surfactants, sulfonic acid surfactants, and the like.

[0404] The fluorine-containing surfactant may be a single fluorine-containing surfactant or a mixture containing two or more fluorine-containing surfactants.

[0405] Examples of the fluorine-containing surfactant include compounds represented by the following formula. The fluorine-containing surfactant may be a mixture of these compounds. In one embodiment of the polymerization, the fluoromonomer is polymerized substantially in the absence of a compound represented by the following formula. F(CF 2 ) 7 COOM, F(CF 2 ) 5 COOM, H(CF 2 ) 6 COOM, H(CF 2 ) 7 COOM, CF 3 O(CF 2 ) 3 OCHFCF 2 COOM, C 3 F 7 OCF(CF 3 )CF 2 OCF(CF 3 )COOM, CF 3 CF 2 CF 2 OCF(CF 3 )COOM, CF 3 CF 2 OCF 2 CF 2 OCF 2 COOM, C 2 F 5 OCF(CF 3 )CF 2 OCF(CF 3 )COOM, CF 3 OCF(CF 3 )CF 2 OCF(CF 3 )COOM, CF 2 ClCF 2 CF 2 OCF(CF 3 )CF 2 OCF 2 COOM、 CF 2 ClCF 2 CF 2 OCF 2 CF(CF 3 )OCF 2 COOM、 CF 2 ClCF(CF 3 )OCF(CF 3 )CF 2 OCF 2 COOM、 CF 2 ClCF(CF 3 )OCF 2 CF(CF 3 )OCF 2 COOM、

Chem.

[0406] By polymerizing a fluoromonomer in an aqueous medium, a polymerization dispersion containing a fluoropolymer, a polymer (I), and an aqueous medium is obtained. The content (solid content concentration) of the fluoropolymer in the polymerization dispersion is usually 10 to 50% by mass, more preferably 15% by mass or more, preferably 40% by mass or less, and more preferably 35% by mass or less.

[0407] The content of the fluoropolymer in the polymerization dispersion is a value obtained by drying 1 g of the polymerization dispersion in a forced-air dryer at 150 °C for 60 minutes, measuring the mass of the heat residue, and calculating the percentage of the mass of the heat residue with respect to the mass (1 g) of the polymerization dispersion.

[0408] After obtaining the polymer dispersion, a composition to be concentrated can be prepared by mixing the obtained polymer dispersion, a nonionic surfactant, and a fluorine-free anionic surfactant.

[0409] The content (solid content concentration) of the fluoropolymer in the composition to be concentrated is usually 8 to 50% by mass, preferably 10% by mass or more, more preferably 15% by mass or more, preferably 40% by mass or less, and more preferably 35% by mass or less.

[0410] The content of the fluoropolymer in the composition is a value obtained by drying 1 g of the composition in a blow dryer at 150 °C for 60 minutes, measuring the mass of the heat residue, and calculating the percentage of the mass of the heat residue with respect to the mass (1 g) of the composition.

[0411] In one embodiment of the composition to be concentrated, a fluorine-containing surfactant is contained. Even when the composition contains a fluorine-containing surfactant, by performing concentration, a fluorine-containing surfactant can be removed from the composition, and an aqueous dispersion of a fluoropolymer with a reduced content of the fluorine-containing surfactant can be obtained.

[0412] In one embodiment of the composition to be concentrated, it substantially does not contain a fluorine-containing surfactant. In the present disclosure, "substantially does not contain a fluorine-containing surfactant" means that the content of the fluorine-containing surfactant in the composition is 10 mass ppm or less, preferably 1 mass ppm or less, more preferably 100 mass ppb or less, still more preferably 10 mass ppb or less, still more preferably 1 mass ppb or less, and particularly preferably, the fluorine-containing surfactant is below the detection limit by measurement by liquid chromatography-mass spectrometry (LC / MS).

[0413] The content of the fluorine-containing surfactant can be measured, for example, by adding methanol to the composition, performing extraction, and analyzing the obtained extract by LC / MS. In order to further improve the extraction efficiency, processes such as Soxhlet extraction and ultrasonic treatment may be performed. From the obtained LC / MS spectrum, molecular weight information is extracted and confirmed for consistency with the structural formula of the candidate fluorosurfactant. Thereafter, an aqueous solution with a content of 5 levels or more of the confirmed fluorosurfactant is prepared, LC / MS analysis of the aqueous solution of each content is performed, the relationship between the content and the area corresponding to that content is plotted, and a calibration curve is drawn. Then, using the calibration curve, the area of the LC / MS chromatogram of the fluorosurfactant in the extract can be converted to the content of the fluorosurfactant.

[0414] According to the production method of the present disclosure, since the content of the polymer (I) in the composition can be reduced by concentration, the polymerization dispersion liquid and the composition obtained as described above can be subjected to concentration without contacting either an anion exchange resin or a cation exchange resin. Further, when a polymerization dispersion liquid is produced by polymerizing a fluoromonomer substantially in the absence of a fluorosurfactant, neither the polymerization dispersion liquid nor the composition substantially contains a fluorosurfactant. For this reason as well, the polymerization dispersion liquid and the composition can be subjected to concentration without contacting an anion exchange resin and a cation exchange resin.

[0415] (Fluoropolymer aqueous dispersion) According to the production method of the present disclosure, a fluoropolymer aqueous dispersion with a reduced content of the polymer (I) is obtained. According to the present disclosure, there is provided a fluoropolymer aqueous dispersion (hereinafter sometimes referred to as the first fluoropolymer aqueous dispersion) containing a polymer (I), a fluoropolymer, a nonionic surfactant, a fluorine-free anionic surfactant, and an aqueous medium, wherein the content of the polymer (I) is less than 1000 mass ppm with respect to the fluoropolymer.

[0416] Since the content of polymer (I) in the first fluoropolymer aqueous dispersion is reduced, the molded article obtained using the first fluoropolymer aqueous dispersion is not affected by the properties due to the inclusion of polymer (I). Therefore, a molded article with excellent properties can be obtained from the first fluoropolymer aqueous dispersion. Furthermore, although the content of polymer (I) in the first fluoropolymer aqueous dispersion is reduced, even when the content of the fluoropolymer is high, it has excellent sedimentation stability and mechanical stability. Therefore, the fluoropolymer in the fluoropolymer aqueous dispersion is less likely to sediment, and the viscosity of the fluoropolymer aqueous dispersion is also less likely to increase. The first fluoropolymer aqueous dispersion has excellent handleability, and by using the first fluoropolymer aqueous dispersion, products such as coating films, impregnated bodies, and cast films can be manufactured with high efficiency, and molding defects during product manufacturing are also less likely to occur.

[0417] The content of polymer (I) in the first fluoropolymer aqueous dispersion is less than 1000 mass ppm, preferably 900 mass ppm or less, and more preferably 800 mass ppm or less, based on the fluoropolymer. Also, the content of polymer (I) in the aqueous dispersion is preferably 0.1 mass ppm or more, more preferably 1.0 mass ppm or more, and even more preferably 10.0 mass ppm or more, based on the fluoropolymer.

[0418] The content of polymer (I) in the aqueous dispersion can be determined by the same method as the content of polymer (I) in the composition.

[0419] The content of the fluoropolymer in the aqueous dispersion of the fluoropolymer obtained by concentration, or the content of the fluoropolymer in the first aqueous dispersion of the fluoropolymer is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 64% by mass or more, even more preferably 65% by mass or more, particularly preferably 66% by mass or more, and most preferably 70% by mass or more, based on the aqueous dispersion. The higher the content of the fluoropolymer in the aqueous dispersion of the fluoropolymer, the easier it is to maintain a high content of the fluoropolymer even when various additives are added to the aqueous dispersion of the fluoropolymer.

[0420] The content of the fluoropolymer in the aqueous dispersion can be specified by measuring the solid content concentration of the aqueous dispersion, the content of the polymer (I) in the aqueous dispersion, the content of the nonionic surfactant in the aqueous dispersion, and the content of the fluorine-free anionic surfactant in the aqueous dispersion, and subtracting the contents of the polymer (I), the nonionic surfactant, and the fluorine-free anionic surfactant from the solid content concentration of the composition. The solid content concentration of the aqueous dispersion is a value obtained by drying 1 g of the aqueous dispersion in a forced-air dryer at 150 °C for 60 minutes, measuring the mass of the heating residue, and calculating the percentage of the mass of the heating residue with respect to the mass (1 g) of the aqueous dispersion. The measurement method of the nonionic surfactant is as described in the examples, and the content of the fluorine-free anionic surfactant can be calculated from the added amount used for producing the aqueous dispersion.

[0421] The content of the nonionic surfactant in the first aqueous dispersion of the fluoropolymer is preferably 1.0% by mass or more, more preferably 1.5% by mass or more, still more preferably 2.0% by mass or more, even more preferably 2.5% by mass or more, particularly preferably 3.0% by mass or more, and most preferably 4.0% by mass or more, based on the fluoropolymer. Also, the content of the nonionic surfactant in the composition is preferably 12% by mass or less, more preferably 10% by mass or less, based on the fluoropolymer.

[0422] The content of the fluorine-free anionic surfactant in the first fluoropolymer aqueous dispersion is preferably 10 to 10,000 ppm by mass, more preferably 50 ppm by mass or more, more preferably 8,000 ppm by mass or less, and still more preferably 5,000 ppm by mass or less, based on the fluoropolymer.

[0423] The viscosity of the first fluoropolymer aqueous dispersion is preferably 2.0 mPa·s or more, more preferably 5.0 mPa·s or more, still more preferably 10.0 mPa·s or more, particularly preferably 15.0 mPa·s or more, preferably 100 mPa·s or less, more preferably 80.0 mPa·s or less, still more preferably 70.0 mPa·s or less, and particularly preferably 60.0 mPa·s or less.

[0424] The viscosity of the aqueous dispersion is measured using a B-type rotational viscometer (manufactured by Toki Sangyo Co., Ltd., rotor No. 2) under the conditions of a rotational speed of 60 rpm, a measurement time of 120 seconds, and a temperature of 25°C.

[0425] The first fluoropolymer aqueous dispersion preferably does not substantially contain a fluorine-containing surfactant. In the present disclosure, "does not substantially contain a fluorine-containing surfactant" means that the content of the fluorine-containing surfactant in the composition is 10 ppm by mass or less, preferably 1 ppm by mass or less, more preferably 100 ppb by mass or less, still more preferably 10 ppb by mass or less, even more preferably 1 ppb by mass or less, and particularly preferably, the fluorine-containing surfactant is below the detection limit by measurement using liquid chromatography-mass spectrometry (LC / MS).

[0426] Also, according to the production method of the present disclosure, a second fluoropolymer aqueous dispersion and a third fluoropolymer aqueous dispersion can also be obtained.

[0427] That is, according to the present disclosure, there is provided an aqueous dispersion of a fluoropolymer containing a polymer (I), a fluoropolymer (excluding the polymer (I)), a nonionic surfactant, and an aqueous medium, wherein the content of the polymer (I) is 500 mass ppm or less with respect to the aqueous dispersion of the fluoropolymer, and the content of the fluoropolymer is 50 mass% or more and 70 mass% or less with respect to the aqueous dispersion of the fluoropolymer (hereinafter sometimes referred to as the second aqueous dispersion of the fluoropolymer).

[0428] The content of the polymer (I) in the second aqueous dispersion of the fluoropolymer is 500 mass ppm or less with respect to the aqueous dispersion of the fluoropolymer, preferably 450 mass ppm or less, more preferably 400 mass ppm or less, still more preferably 350 mass ppm or less, preferably 0.1 mass ppm or more, more preferably 1.0 mass ppm or more, and still more preferably 10.0 mass ppm or more.

[0429] The content of the fluoropolymer in the second aqueous dispersion of the fluoropolymer is 50 mass% or more and 70 mass% or less with respect to the aqueous dispersion of the fluoropolymer, preferably 55 mass% or more, more preferably 57 mass% or more, still more preferably 60 mass% or more, preferably 68 mass% or less, more preferably 67 mass% or less, and still more preferably 65 mass% or less.

[0430] The viscosity of the second aqueous dispersion of the fluoropolymer is preferably 5.0 mPa·s or more, more preferably 10.0 mPa·s or more, still more preferably 15.0 mPa·s or more, yet still more preferably 20.0 mPa·s or more, particularly preferably 25.0 mPa·s or more, preferably 300 mPa·s or less, more preferably 250 mPa·s or less, still more preferably 200 mPa·s or less, yet still more preferably 150 mPa·s or less, and particularly preferably 100 mPa·s or less.

[0431] The content of the nonionic surfactant in the second fluoropolymer aqueous dispersion is preferably 4.0% by mass or more, more preferably 5.0% by mass or more, still more preferably 5.5% by mass or more, preferably 12% by mass or less, more preferably 10% by mass or less, still more preferably 8.0% by mass or less, and even more preferably 7.0% by mass or less, based on the fluoropolymer.

[0432] The second fluoropolymer aqueous dispersion may contain a fluorine-free anionic surfactant. The content of the fluorine-free anionic surfactant in the second fluoropolymer aqueous dispersion is preferably 10 ppm by mass or more, more preferably 50 ppm by mass or more, preferably 10,000 ppm by mass or less, more preferably 8,000 ppm by mass or less, and still more preferably 5,000 ppm by mass or less, based on the fluoropolymer.

[0433] The second fluoropolymer aqueous dispersion preferably does not substantially contain a fluorine-containing surfactant. In the present disclosure, "not substantially containing a fluorine-containing surfactant" means that the content of the fluorine-containing surfactant in the composition is 10 ppm by mass or less, preferably 1 ppm by mass or less, more preferably 100 ppb by mass or less, still more preferably 10 ppb by mass or less, even more preferably 1 ppb by mass or less, and particularly preferably, the fluorine-containing surfactant is below the detection limit by measurement using liquid chromatography-mass spectrometry (LC / MS).

[0434] Furthermore, according to the present disclosure, there is provided a fluoropolymer aqueous dispersion containing a fluoropolymer, a nonionic surfactant, and an aqueous medium, which substantially does not contain a fluorine-containing surfactant, has a viscosity at 25°C of 100 mPa·s or less, and the color tone of the impregnated fiber obtained by impregnating a glass fiber with the fluoropolymer aqueous dispersion and firing at 380°C is L * in the CIELAB color scale is 74.0 or more, or a *is 1.0 or less, the fluoropolymer content is 50% by mass or more and 70% by mass or less, and the nonionic surfactant content is 4.0% by mass or more and 12% by mass or less, based on the fluoropolymer aqueous dispersion (hereinafter sometimes referred to as a third aqueous fluoropolymer dispersion).

[0435] The viscosity of the third aqueous fluoropolymer dispersion is 100 mPa·s or less, preferably 70 mPa·s or less, more preferably 60 mPa·s or less, even more preferably 50 mPa·s or less, preferably 5.0 mPa·s or more, more preferably 10.0 mPa·s or more, even more preferably 15.0 mPa·s or more, still more preferably 20.0 mPa·s or more, and particularly preferably 25.0 mPa·s or more.

[0436] One of the features of the third fluoropolymer aqueous dispersion is L * impregnated fibers with large a * Thus, the impregnated fiber obtained by using the third aqueous fluoropolymer dispersion has a low color tone (L * , a * , b * ) of which L * is large or a * Therefore, the third fluoropolymer aqueous dispersion can provide not only less colored impregnated fibers but also less colored molded products. The color tone of the impregnated fiber obtained by impregnating the third fluoropolymer aqueous dispersion into a glass fiber and baking it at 380°C is smaller than L on the CIELAB color scale. * or greater than 74.0, or a * The color tone of the impregnated fiber can be adjusted within a desired range by adjusting the content of polymer (I) in the aqueous fluoropolymer dispersion, etc.

[0437] The color tone exhibited by the impregnated fiber is L in the CIELAB color scale * is preferably a value equal to or higher than the lower limit value described later, L in the CIELAB color scale * is more preferably a value within the range of the lower limit value and the upper limit value described later.

[0438] The color tone exhibited by the impregnated fiber is a in the CIELAB color scale * is preferably a value equal to or lower than the upper limit value described later, a in the CIELAB color scale * is more preferably a value within the range of the lower limit value and the upper limit value described later.

[0439] The color tone exhibited by the impregnated fiber is L in the CIELAB color scale * is 74.0 or higher, and further, a in the CIELAB color scale * is preferably 1.0 or lower.

[0440] The color tone exhibited by the impregnated fiber is L in the CIELAB color scale * is a value equal to or higher than the lower limit value described later, and further, a in the CIELAB color scale * is preferably a value equal to or lower than the upper limit value described later, L in the CIELAB color scale * is a value within the range of the lower limit value and the upper limit value described later, and further, a in the CIELAB color scale * is more preferably a value within the range of the lower limit value and the upper limit value described later.

[0441] The color tone exhibited by the impregnated fiber is L in the CIELAB color scale * As the lower limit value, in order of preference, are 74.0, 74.5, 75.0, 75.5, 76.0, 76.5, 77.0. The color tone exhibited by the impregnated fiber is L in the CIELAB color scale* The upper limit value may be 100.

[0442] The color tone exhibited by the impregnated fiber is a in the CIELAB color scale * As the lower limit values, in order of preference, are -1.5, -1.0, -0.7, -0.5, -0.3, 0.0. The color tone exhibited by the impregnated fiber is a in the CIELAB color scale * As the upper limit values, in order of preference, are 1.0, 0.7, 0.5, 0.2.

[0443] The color tone exhibited by the impregnated fiber is b in the CIELAB color scale * As the lower limit values, in order of preference, are -2.0, -1.0, 0.0, 1.0, 2.0, 3.0, 4.0, 5.0. The color tone exhibited by the impregnated fiber is b in the CIELAB color scale * As the upper limit values, in order of preference, are 10.0, 9.5, 9.0, 8.5, 8.0, 7.5, 7.0, 6.5, 6.0.

[0444] The impregnated fiber for measuring the color tone is prepared by impregnating a fluoropolymer aqueous dispersion into glass fiber (ATE11100 manufactured by Sakai Sangyo Co., Ltd.), drying, firing at 380 °C for 3 minutes, and repeating impregnation, drying, and firing until the content ratio of the fluoropolymer to the mass of the impregnated fiber becomes 70 to 80% by mass. The color tone (L * , a * , b * ) of the obtained impregnated fiber can be measured based on a measurement method conforming to JIS Z 8781-4:2013 using a color meter ZE6000 manufactured by Nippon Denshoku Industries Co., Ltd.

[0445] The content of the fluoropolymer in the third aqueous dispersion of fluoropolymer is 50% by mass or more and 70% by mass or less, preferably 55% by mass or more, more preferably 57% by mass or more, still more preferably 60% by mass or more, preferably 68% by mass or less, more preferably 67% by mass or less, and still more preferably 65% by mass or less, based on the aqueous dispersion of fluoropolymer.

[0446] The content of the nonionic surfactant in the third aqueous dispersion of fluoropolymer is 4.0% by mass or more and 12% by mass or less, preferably 5.0% by mass or more, more preferably 5.5% by mass or more, preferably 10% by mass or less, more preferably 8.0% by mass or less, and still more preferably 7.0% by mass or less, based on the fluoropolymer.

[0447] The third aqueous dispersion of fluoropolymer may contain polymer (I). The content of polymer (I) in the third aqueous dispersion of fluoropolymer is preferably 500 ppm by mass or less, more preferably 450 ppm by mass or less, still more preferably 400 ppm by mass or less, yet still more preferably 350 ppm by mass or less, preferably 0.1 ppm by mass or more, more preferably 1.0 ppm by mass or more, and still more preferably 10.0 ppm by mass or more, based on the aqueous dispersion of fluoropolymer.

[0448] The third aqueous dispersion of fluoropolymer may contain a fluorine-free anionic surfactant. The content of the fluorine-free anionic surfactant in the third aqueous dispersion of fluoropolymer is preferably 10 ppm by mass or more, more preferably 50 ppm by mass or more, preferably 10000 ppm by mass or less, more preferably 8000 ppm by mass or less, and still more preferably 5000 ppm by mass or less, based on the fluoropolymer.

[0449] The third fluoropolymer aqueous dispersion substantially does not contain a fluorosurfactant. In the present disclosure, "substantially does not contain a fluorosurfactant" means that the content of the fluorosurfactant in the composition is 10 mass ppm or less, preferably 1 mass ppm or less, more preferably 100 mass ppb or less, still more preferably 10 mass ppb or less, even more preferably 1 mass ppb or less, and particularly preferably, the fluorosurfactant is below the detection limit by measurement using liquid chromatography-mass spectrometry (LC / MS).

[0450] (Other components) The fluoropolymer aqueous dispersion may contain other components. Examples of the other components include preservatives. By containing a preservative in the fluoropolymer aqueous dispersion, even when the fluoropolymer aqueous dispersion is stored for a long period, it is possible to suppress the sedimentation of the fluoropolymer and to suppress the spoilage and bacterial growth of the fluoropolymer aqueous dispersion.

[0451] Examples of the preservative include isothiazolone-based, azole-based, pronopol, chlorothalonil, methylsulfonyltetrachloropyridine, carbendazim, fluorophollet, disodium diacetate, diiodomethyl paratolyl sulfone, and the like.

[0452] The content of the preservative in the fluoropolymer aqueous dispersion is preferably 0.01 to 0.5% by mass, more preferably 0.05 to 0.2% by mass, based on the fluoropolymer.

[0453] In addition, examples of other components include water-soluble polymer compounds. Examples of water-soluble polymer compounds include methyl cellulose, alumina sol, polyvinyl alcohol, carboxylated vinyl polymer, polyethylene oxide (dispersion stabilizer), polyethylene glycol (dispersion stabilizer), polyvinyl pyrrolidone (dispersion stabilizer), phenol resin, urea resin, epoxy resin, melamine resin, polyester resin, polyether resin, acrylic silicone resin, silicone resin, silicone polyester resin, polyurethane resin, and the like.

[0454] The fluoropolymer aqueous dispersion can be used as an aqueous coating paint by blending compounding agents such as known pigments, thickeners, dispersants, defoamers, antifreezing agents, film-forming aids, etc., or by further compounding with other polymer compounds.

[0455] Next, the fluoropolymer in the aqueous dispersion obtained by the production method of the present disclosure and the fluoropolymer in the aqueous dispersion of the present disclosure will be described in more detail.

[0456] (Fluoropolymer) Examples of fluoropolymers include TFE polymers in which the monomer with the highest molar fraction in the polymer (hereinafter, "the most abundant monomer") is TFE, VDF polymers in which the most abundant monomer is VDF, CTFE polymers in which the most abundant monomer is CTFE, and the like.

[0457] The above fluoropolymer preferably has an ion exchange rate (IXR) higher than 53. Preferred fluoropolymers have no ionic groups at all or have a limited number of ionic groups that result in an ion exchange rate higher than about 100. The ion exchange rate of preferred fluoropolymers is preferably 1000 or more, more preferably 2000 or more, and even more preferably 5000 or more.

[0458] As the TFE polymer, it may preferably be a TFE homopolymer, or may also be a copolymer composed of (1) TFE, (2) one or more fluorine-containing monomers other than TFE having 2 to 8 carbon atoms, particularly VDF, HFP or CTFE, and (3) other monomers. Examples of the above (3) other monomers include fluoro(alkyl vinyl ether) having an alkyl group having 1 to 5 carbon atoms, particularly 1 to 3 carbon atoms; fluorodioxole; perfluoroalkyl ethylene; ω-hydroperfluoroolefin and the like.

[0459] As the TFE polymer, it may also be a copolymer of TFE and one or more fluorine-free monomers. Examples of the above fluorine-free monomers include alkenes such as ethylene and propylene; vinyl esters; vinyl ethers. As the TFE polymer, it may also be a copolymer of TFE, one or more fluorine-containing monomers having 2 to 8 carbon atoms, and one or more fluorine-free monomers.

[0460] As the VDF polymer, it may preferably be a VDF homopolymer [PVDF], or may also be a copolymer composed of (1) VDF, (2) one or more fluoroolefins other than VDF having 2 to 8 carbon atoms, particularly TFE, HFP or CTFE, and (3) perfluoro(alkyl vinyl ether) having an alkyl group having 1 to 5 carbon atoms, particularly 1 to 3 carbon atoms and the like.

[0461] As the CTFE polymer, it may preferably be a CTFE homopolymer, or may also be a copolymer composed of (1) CTFE, (2) one or more fluoroolefins other than CTFE having 2 to 8 carbon atoms, particularly TFE or HFP, and (3) perfluoro(alkyl vinyl ether) having an alkyl group having 1 to 5 carbon atoms, particularly 1 to 3 carbon atoms.

[0462] The CTFE polymer may also be a copolymer of CTFE and one or more fluorine-free monomers. Examples of the fluorine-free monomers include alkenes such as ethylene and propylene; vinyl esters; vinyl ethers and the like.

[0463] The above fluoropolymer can be glassy, plastic or elastomeric. These are amorphous or partially crystalline and can be subjected to compression sintering, melt processing or non-melt processing.

[0464] In the production method of the present disclosure, for example, (I) as the non-melt processable fluororesin, tetrafluoroethylene polymer [TFE polymer (PTFE)], (II) as the melt processable fluororesin, ethylene / TFE copolymer [ETFE], TFE / HFP copolymer [FEP], TFE / perfluoro(alkyl vinyl ether) copolymer [PFA, MFA, etc.], TFE / perfluoroallyl ether copolymer, TFE / VDF copolymer, electrolyte polymer precursor, (III) as the fluororubber, TFE / propylene copolymer, TFE / propylene / third monomer copolymer (the above third monomer is VDF, HFP, CTFE, fluoroalkyl vinyl ethers, etc.), copolymer composed of TFE and fluoroalkyl vinyl ethers; HFP / ethylene copolymer, HFP / ethylene / TFE copolymer; PVDF; thermoplastic elastomers such as VDF / HFP copolymer, HFP / ethylene copolymer, VDF / TFE / HFP copolymer; and fluorine-containing segmented polymers described in Japanese Patent Publication No. 61-49327 can be preferably produced.

[0465] As the above fluoropolymer, a fluororesin is preferable, and among them, a fluororesin having a fluorine substitution rate of 50% or more calculated by the following formula is more preferable, a fluororesin having a fluorine substitution rate exceeding 50% is still more preferable, a fluororesin having a fluorine substitution rate of 55% or more is even more preferable, a fluororesin having a fluorine substitution rate of 60% or more is even more preferable, a fluororesin having a fluorine substitution rate of 75% or more is even more preferable, a fluororesin having a fluorine substitution rate of 80% or more is particularly preferable, and a fluororesin having a fluorine substitution rate of 90 to 100%, that is, a perfluororesin is most preferable. (Formula) Fluorine substitution rate (%) = (number of fluorine atoms bonded to carbon atoms constituting the fluoropolymer) / ((number of hydrogen atoms bonded to carbon atoms constituting the fluoropolymer) + (number of fluorine atoms and chlorine atoms bonded to carbon atoms constituting the fluoropolymer)) × 100

[0466] As the above perfluororesin, a fluororesin having a fluorine substitution rate of 95 to 100% is more preferable, PTFE, FEP or PFA is still more preferable, and PTFE is particularly preferable.

[0467] The above fluoropolymer may have a core-shell structure. Examples of the fluoropolymer having a core-shell structure include modified PTFE containing a core of high molecular weight PTFE and a shell of lower molecular weight PTFE or modified PTFE in the particles. Examples of such modified PTFE include PTFE described in Japanese Patent Application Laid-Open No. 2005-527652.

[0468] The above core-shell structure may take the following structures. Core: TFE homopolymer Shell: TFE homopolymer Core: Modified PTFE Shell: TFE homopolymer Core: Modified PTFE Shell: Modified PTFE Core: TFE homopolymer Shell: Modified PTFE Core: Low molecular weight PTFE Shell: High molecular weight PTFE Core: High molecular weight PTFE; Shell: Low molecular weight PTFE

[0469] In the fluoropolymer having the above core-shell structure, the lower limit of the ratio of the core is preferably 0.5% by mass, more preferably 1.0% by mass, still more preferably 3.0% by mass, particularly preferably 5.0% by mass, and most preferably 10.0% by mass. The upper limit of the ratio of the core is preferably 99.5% by mass, more preferably 99.0% by mass, still more preferably 98.0% by mass, even more preferably 97.0% by mass, particularly preferably 95.0% by mass, and most preferably 90.0% by mass.

[0470] In the fluoropolymer having the above core-shell structure, the lower limit of the ratio of the shell is preferably 0.5% by mass, more preferably 1.0% by mass, still more preferably 3.0% by mass, particularly preferably 5.0% by mass, and most preferably 10.0% by mass. The upper limit of the ratio of the shell is preferably 99.5% by mass, more preferably 99.0% by mass, still more preferably 98.0% by mass, even more preferably 97.0% by mass, particularly preferably 95.0% by mass, and most preferably 90.0% by mass.

[0471] In the fluoropolymer having the above core-shell structure, the above core or the above shell can also be configured in two or more layers. For example, it may be a fluoropolymer having a three-layer structure including a core central portion of modified PTFE, a core outer layer portion of a TFE homopolymer, and a shell of modified PTFE.

[0472] Examples of the fluoropolymer having the above core-shell structure also include those in which one particle of the above fluoropolymer has a plurality of cores.

[0473] The above (I) non-melt processable fluororesin, (II) melt processable fluororesin, and (III) fluororubber, which are preferably produced by the production method of the present disclosure, are preferably produced in the following modes.

[0474] (I) Non-melt processable fluororesin In the manufacturing method of the present disclosure, the polymerization of TFE is usually carried out at a polymerization temperature of 10 to 150°C and a polymerization pressure of 0.05 to 5 MPaG. For example, the polymerization temperature is more preferably 30°C or higher, and even more preferably 50°C or higher. Also, it is more preferably 120°C or lower, and even more preferably 100°C or lower. Further, the polymerization pressure is more preferably 0.3 MPaG or higher, even more preferably 0.5 MPaG or higher, and also more preferably 5.0 MPaG or lower, and even more preferably 3.0 MPaG or lower. In particular, from the viewpoint of improving the yield of the fluoropolymer, 1.0 MPaG or higher is preferable, 1.2 MPaG or higher is more preferable, 1.5 MPaG or higher is even more preferable, and 2.0 MPaG or higher is more preferable.

[0475] In one aspect, for the above polymerization, pure water is charged into a pressure-resistant reaction vessel equipped with a stirrer, deoxygenated, then TFE is charged, brought to a predetermined temperature, and a polymerization initiator is added to start the reaction. When the pressure decreases as the reaction progresses, additional TFE is continuously or intermittently added to maintain the initial pressure. When a predetermined amount of TFE has been supplied, the supply is stopped, the TFE in the reaction vessel is purged, the temperature is returned to room temperature, and the reaction is terminated. Additional TFE may be continuously or intermittently added so that the pressure does not decrease.

[0476] In the production of the above TFE polymer (PTFE), various known modified monomers can also be used in combination. In the present disclosure, the above TFE polymer is a concept that includes not only a TFE homopolymer but also a copolymer of TFE and a modified monomer that is non-melt processable (hereinafter referred to as "modified PTFE").

[0477] The above modified monomer is not particularly limited as long as it can copolymerize with TFE, and examples include fluoromonomers and non-fluoromonomers. Also, one type of modified monomer may be used, or a plurality of types may be used.

[0478] The non-fluoromonomer is not particularly limited, and has the general formula: CH 2 =CR Q1 -LR Q2 (In the formula, R Q1 represents a hydrogen atom or an alkyl group. L represents a single bond, -CO-O-*, -O-CO-* or -O-. * represents the bonding position with R Q2 . R Q2 represents a hydrogen atom, an alkyl group or a nitrile group.) Examples of the monomer represented by the formula include those mentioned below.

[0479] Examples of the non-fluoromonomer include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, vinyl methacrylate, vinyl acetate, acrylic acid, methacrylic acid, acrylonitrile, methacrylonitrile, ethyl vinyl ether, cyclohexyl vinyl ether and the like. Among them, butyl methacrylate, vinyl acetate and acrylic acid are preferable as the non-fluoromonomer.

[0480] Examples of the fluoromonomer include perfluoroolefins such as hexafluoropropylene [HFP]; hydrogen-containing fluoroolefins such as trifluoroethylene and vinylidene fluoride [VDF]; perhaloolefins such as chlorotrifluoroethylene; perfluorovinyl ethers; (perfluoroalkyl)ethylene; perfluoroallyl ether and the like.

[0481] The perfluorovinyl ether is not particularly limited. For example, the general formula (A): CF 2 =CF-ORf (A) (In the formula, Rf represents a perfluoro organic group.) Examples of the perfluoro unsaturated compound represented by the formula include those mentioned below. In the present disclosure, the above-mentioned "perfluoro organic group" means an organic group in which all hydrogen atoms bonded to carbon atoms are substituted with fluorine atoms. The perfluoro organic group may have an ether oxygen.

[0482] Examples of the perfluoro vinyl ether include perfluoro(alkyl vinyl ether) [PAVE] in which Rf is a perfluoroalkyl group having 1 to 10 carbon atoms in the general formula (A). The number of carbon atoms of the perfluoroalkyl group is preferably 1 to 5.

[0483] Examples of the perfluoroalkyl group in the PAVE include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, a perfluorohexyl group, and the like.

[0484] Examples of the perfluoro vinyl ether further include those in which Rf is a perfluoro(alkoxyalkyl) group having 4 to 9 carbon atoms in the general formula (A), those in which Rf is a group represented by the following formula:

[0485]

Chemical formula

[0486] (wherein m represents 0 or an integer of 1 to 4), those in which Rf is a group represented by the following formula:

[0487] CF 3 CF 2 CF 2 -(O-CF(CF 3 )-CF 2 ) n - (wherein n represents an integer of 1 to 4), and the like.

[0488] Examples of the hydrogen-containing fluoroolefin include CH 2 =CF 2 , CFH=CH 2 , CFH=CF 2 , CH 2 =CFCF 3 , CH 2 =CHCF 3 , CHF=CHCF 3 (E isomer), CHF=CHCF 3 (Z isomer), and the like.

[0489] (Perfluoroalkyl)ethylene (PFAE) is not particularly limited, and examples thereof include (perfluorobutyl)ethylene (PFBE), (perfluorohexyl)ethylene, and the like.

[0490] Examples of the perfluoroallyl ether include General formula: CF 2 =CF-CF 2 -ORf (wherein, Rf represents a perfluoro organic group). Examples of the fluoromonomer represented by the formula include

[0491] Rf in the above general formula is the same as Rf in general formula (A). As Rf, a perfluoroalkyl group having 1 to 10 carbon atoms or a perfluoroalkoxyalkyl group having 1 to 10 carbon atoms is preferable. Examples of the perfluoroallyl ether include CF 2 =CF-CF 2 -O-CF 3 CF 2 =CF-CF 2 -O-C 2 F 5 CF 2 =CF-CF 2 -O-C 3 F 7 CF 2 =CF-CF 2 -O-C 4 F 9 At least one selected from the group consisting of 2 =CF-CF 2 -O-C 2 F 5 CF 2 =CF-CF 2 -O-C 3 F 7 CF 2 =CF-CF 2 -O-C 4 F 9 is more preferable, and at least one selected from the group consisting of 2 =CF-CF 2 -O-CF 2 CF2 CF 3 is more preferable.

[0492] As the above-mentioned modified monomer, a modified monomer (3) having a monomer reactivity ratio of 0.1 to 8 is also preferably exemplified. By the presence of the modified monomer (3), PTFE particles having a small particle size can be obtained, and an aqueous dispersion having high dispersion stability can be obtained.

[0493] Here, the monomer reactivity ratio in the copolymerization with TFE is a value obtained by dividing the rate constant when the growing radical reacts with TFE by the rate constant when the growing radical reacts with the modified monomer when the growing radical is less than the repeating unit based on TFE. The lower this value, the higher the reactivity of the modified monomer with TFE. The monomer reactivity ratio can be calculated from the Fineman-Ross equation by determining the composition in the produced polymer immediately after the start of copolymerization of TFE and the modified monomer.

[0494] The above copolymerization is carried out in a 6.0 L stainless steel autoclave using 3600 g of deionized and degassed water, ammonium perfluorooctanoate at 1000 mass ppm with respect to the above water, and 100 g of paraffin wax at a pressure of 0.78 MPaG and a temperature of 70 °C. 0.05 g, 0.1 g, 0.2 g, 0.5 g, and 1.0 g of the modified monomer are added to the reactor respectively, and 0.072 g of ammonium persulfate (20 mass ppm with respect to water) is added, and TFE is continuously supplied to maintain a polymerization pressure of 0.78 MPaG. When the TFE charge reaches 1000 g, stirring is stopped and the reactor is depressurized until it reaches atmospheric pressure. After cooling, the paraffin wax is separated to obtain an aqueous dispersion containing the produced polymer. The above aqueous dispersion is stirred to coagulate the produced polymer and dried at 150 °C. The composition in the obtained produced polymer is calculated by appropriately combining NMR, FT-IR, elemental analysis, and X-ray fluorescence analysis according to the type of monomer.

[0495] As the modified monomer (3) having a monomer reactivity ratio of 0.1 to 8, it is preferably at least one selected from the group consisting of modified monomers represented by the formulas (3a) to (3d). CH 2 =CH-Rf 1 (3a) (In the formula, Rf 1 is a perfluoroalkyl group having 1 to 10 carbon atoms.) CF 2 =CF-O-Rf 2 (3b) (In the formula, Rf 2 is a perfluoroalkyl group having 1 to 2 carbon atoms.) CF 2 =CF-O-(CF 2 ) n CF=CF 2 (3c) (In the formula, n is 1 or 2.)

[0496]

Chemical formula

[0497]

Chemical formula

[0498] The content of the modified monomer (3) unit is preferably in the range of 0.00001 to 1.0% by mass based on all the polymerization units of PTFE. As the lower limit, 0.0001% by mass is more preferable, 0.0005% by mass is more preferable, 0.001% by mass is still more preferable, and 0.005% by mass is even more preferable. As the upper limit, in order of preference, they are 0.90% by mass, 0.50% by mass, 0.40% by mass, 0.30% by mass, 0.20% by mass, 0.15% by mass, 0.10% by mass, 0.08% by mass, 0.05% by mass, 0.01% by mass.

[0499] As the above-mentioned modified monomer, since it is possible to obtain an aqueous dispersion having a small average primary particle diameter of primary particles, a small aspect ratio of primary particles, and excellent stability, hexafluoropropylene, chlorotrifluoroethylene, vinylidene fluoride, perfluoro(alkyl vinyl ether), (perfluoroalkyl)ethylene, ethylene, and at least one selected from the group consisting of modified monomers having a functional group capable of reacting by radical polymerization and a hydrophilic group are preferable. By using the above-mentioned modified monomer, it is possible to obtain an aqueous dispersion of PTFE having a smaller average primary particle diameter, a smaller aspect ratio of primary particles, and excellent dispersion stability. Further, it is possible to obtain an aqueous dispersion having less uncondensed polymer.

[0500] From the viewpoint of reactivity with TFE, the above-mentioned modified monomer preferably contains at least one selected from the group consisting of hexafluoropropylene, perfluoro(alkyl vinyl ether), and (perfluoroalkyl)ethylene. More preferably, it contains at least one selected from the group consisting of hexafluoropropylene, perfluoro(methyl vinyl ether), perfluoro(propyl vinyl ether), (perfluorobutyl)ethylene, (perfluorohexyl)ethylene, and (perfluorooctyl)ethylene. The total amount of the above-mentioned hexafluoropropylene unit, perfluoro(alkyl vinyl ether) unit, and (perfluoroalkyl)ethylene unit is preferably in the range of 0.00001 to 1% by mass based on the total polymerization units of PTFE. As the lower limit of the above total amount, 0.0001% by mass is more preferable, 0.0005% by mass is more preferable, 0.001% by mass is still more preferable, and 0.005% by mass is still more preferable. As the upper limit, in order of preference, they are 0.80% by mass, 0.70% by mass, 0.50% by mass, 0.40% by mass, 0.30% by mass, 0.20% by mass, 0.15% by mass, 0.10% by mass, 0.08% by mass, 0.05% by mass, 0.01% by mass.

[0501] It is also preferable that the modified monomer contains a modified monomer having a functional group capable of reacting by radical polymerization and a hydrophilic group (hereinafter referred to as "modified monomer (A)").

[0502] By the presence of the modified monomer (A), PTFE particles having a small primary particle diameter can be obtained, and an aqueous dispersion having high dispersion stability can be obtained. In addition, the amount of uncondensed polymer can be reduced. Furthermore, the aspect ratio of the primary particles can be reduced.

[0503] The amount of the modified monomer (A) used is preferably an amount exceeding the amount corresponding to 0.1 mass ppm of the aqueous medium, more preferably an amount exceeding 0.5 mass ppm, still more preferably an amount exceeding 1.0 mass ppm, still more preferably 5 mass ppm or more, and particularly preferably 10 mass ppm or more. If the amount of the modified monomer (A) used is too small, the average primary particle diameter of the obtained PTFE may not be reduced. The amount of the modified monomer (A) used may be within the above range. For example, the upper limit can be set to 5000 mass ppm. In the above production method, in order to improve the stability of the aqueous dispersion during or after the reaction, the modified monomer (A) may be added to the system during the reaction.

[0504] Since the modified monomer (A) has high water solubility, even if the unreacted modified monomer (A) remains in the aqueous dispersion, it is easy to remove in the concentration step or the coagulation / washing step.

[0505] The modified monomer (A) is incorporated into the produced polymer during the polymerization process. However, since the concentration of the modified monomer (A) itself in the polymerization system is low and the amount incorporated into the polymer is small, there are no problems such as a decrease in the heat resistance of PTFE or coloring after firing.

[0506] Examples of the hydrophilic group in the modified monomer (A) include -NH 2 , -PO 3 M, -OPO 3 M, -SO3 M, -OSO 3 M, -COOM (in each formula, M is H, a metal atom, NR 7y 4 , imidazolium which may have a substituent, pyridinium which may have a substituent or phosphonium which may have a substituent, R 7y is H or an organic group, and they may be the same or different. Any two of them may be bonded to each other to form a ring.). Examples include. Among the above hydrophilic groups, -SO 3 M or -COOM is preferable. As the organic group in R 7y , an alkyl group is preferable. As R 7y , H or a C 1-10 organic group is preferable, H or a C 1-4 organic group is more preferable, and H or a C 1-4 alkyl group is even more preferable. Examples of the above metal atom include monovalent and divalent metal atoms, such as alkali metals (Group 1), alkaline earth metals (Group 2), etc., and Na, K or Li is preferable.

[0507] Examples of the "functional group capable of reacting by radical polymerization" in the above modified monomer (A) include groups having an ethylenically unsaturated bond such as a vinyl group and an allyl group. The group having an ethylenically unsaturated bond is represented by the following formula: CX e X g =CX f R- (In the formula, X e , X f and X g are each independently F, Cl, H, CF 3 , CF 2 H, CFH 2 , or CH 3 ; and R is a linking group.). The linking group of R includes the linking group as R a described later. Preferably -CH=CH 2 , -CF=CH 2、 -CH=CF 2、 -CF=CF 2 , -CH 2 -CH=CH2 , -CF 2 -CF=CH 2 , -CF 2 -CF=CF 2 , -(C=O)-CH=CH 2 , -(C=O)-CF=CH 2 , -(C=O)-CH=CF 2 , -(C=O)-CF=CF 2 , -(C=O)-C(CH 3 )=CH 2 , -(C=O)-C(CF 3 )=CH 2 , -(C=O)-C(CH 3 )=CF 2 , -(C=O)-C(CF 3 )=CF 2 , -O-CH 2 -CH=CH 2 , -O-CF 2 -CF=CH 2 , -O-CH 2 -CH=CF 2 , -O-CF 2 -CF=CF 2 Groups having unsaturated bonds such as the following can be mentioned.

[0508] Since the modified monomer (A) has a functional group capable of reacting by radical polymerization, when used in the above polymerization, it is presumed to react with the fluorine-containing monomer at the initial stage of the polymerization reaction to form particles having a hydrophilic group derived from the modified monomer (A) and high stability. Therefore, when polymerization is carried out in the presence of the modified monomer (A), it is considered that the number of particles increases.

[0509] In the above polymerization, one kind of the modified monomer (A) may be present, or two or more kinds may be present.

[0510] In the above polymerization, a compound having an unsaturated bond can be used as the modified monomer (A).

[0511] The modified monomer (A) has the general formula (4): CX i X k=CX j R a -(CZ 1 Z 2 ) k -Y 3 (4) (wherein X i 、X j and X k are each independently F, Cl, H or CF 3 ; Y 3 is a hydrophilic group; R a is a linking group; Z 1 and Z 2 are each independently H, F or CF 3 ; and k is 0 or 1) is preferred. Examples of the hydrophilic group include -NH 2 、-PO 3 M, -OPO 3 M, -SO 3 M, -OSO 3 M, -COOM (in each formula, M is H, a metal atom, NR 7y 4 , imidazolium which may have a substituent, pyridinium which may have a substituent or phosphonium which may have a substituent, R 7y is H or an organic group, and they may be the same or different. Any two of them may be bonded to each other to form a ring.). Among them, -SO 3 M or -COOM is preferred. The organic group in R 7y is preferably an alkyl group. R 7y is preferably H or an organic group of C 1-10 , more preferably H or an organic group of C 1-4 , and even more preferably H or an alkyl group of C 1-4 . Examples of the metal atom include monovalent and divalent metal atoms, such as alkali metals (Group 1), alkaline earth metals (Group 2), etc., and Na, K or Li is preferred. By using the modified monomer (A), an aqueous dispersion having a smaller average primary particle diameter and better stability can be obtained. In addition, the aspect ratio of the primary particles can also be made smaller.

[0512] The above R a is a linking group. In the present disclosure, the "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, may be 4 or more, may be 8 or more, may be 10 or more, and may be 20 or more. The upper limit is not limited, for example, it may be 100 or less, and may be 50 or less. The above linking group may be linear or branched, cyclic or acyclic, saturated or unsaturated, substituted or unsubstituted, and optionally contains one or more heteroatoms selected from the group consisting of sulfur, oxygen, and nitrogen, and optionally contains one or more functional groups selected from the group consisting of ester, amide, sulfonamide, carbonyl, carbonate, urethane, urea, and carbamate. The above linking group may not contain a carbon atom and may be a chain heteroatom such as oxygen, sulfur, or nitrogen.

[0513] The above R a is preferably, for example, a chain heteroatom such as oxygen, sulfur, nitrogen, or a divalent organic group. R a When R is a divalent organic group, the hydrogen atom bonded to the carbon atom may be replaced by a halogen other than fluorine, such as chlorine, etc., and may or may not contain a double bond. Also, R a may be either linear or branched, and may be either cyclic or acyclic. Also, R a may contain a functional group (for example, ester, ether, ketone, amine, halide, etc.). R a may also be a non-fluorinated divalent organic group, or a partially fluorinated or perfluorinated divalent organic group. R aExamples thereof include a hydrocarbon group in which no fluorine atom is bonded to a carbon atom, a hydrocarbon group in which some of the hydrogen atoms bonded to a carbon atom are substituted with fluorine atoms, a hydrocarbon group in which all of the hydrogen atoms bonded to a carbon atom are substituted with fluorine atoms, -(C=O)-, -(C=O)-O-, or a hydrocarbon group containing an ether bond, and these may contain an oxygen atom, may contain a double bond, and may contain a functional group.

[0514] R a is preferably a hydrocarbon group having 1 to 100 carbon atoms which may contain -(C=O)-, -(C=O)-O-, or an ether bond and may contain a carbonyl group, and some or all of the hydrogen atoms bonded to the carbon atoms of the hydrocarbon group may be substituted with fluorine. R a is preferably -(CH 2 ) a -, -(CF 2 ) a -, -O-(CF 2 ) a -, -(CF 2 ) a -O-(CF 2 ) b -, -O(CF 2 ) a -O-(CF 2 ) b -, -(CF 2 ) a -[O-(CF 2 ) b c -, -O(CF 2 ) a -[O-(CF 2 ) b c -, -[(CF 2 ) a -O] b -[(CF 2 ) c -O] d -, -O[(CF 2 ) a -O] b -[(CF 2 ) c -O] d ​​-, -O-[CF 2 CF(CF 3 )O] a -(CF 2 ) b -, -(C=O)-, -(C=O)-O-, -(C=O)-(CH 2 ) a -, -(C=O)-(CF 2 ) a -, -(C=O)-O-(CH 2 ) a -, -(C=O)-O-(CF 2 ) a -, -(C=O)-[(CH 2 ) a -O] b -, -(C=O)-[(CF 2 ) a -O] b -, -(C=O)-O[(CH 2 ) a -O] b -, -(C=O)-O[(CF 2 ) a -O] b -, -(C=O)-O[(CH 2 ) a -O] b -(CH 2 ) c -, -(C=O)-O[(CF 2 ) a -O] b -(CF 2 ) c -, -(C=O)-(CH 2 ) a -O-(CH 2 ) b -, -(C=O)-(CF 2 ) a -O-(CF 2 ) b -, -(C=O)-O-(CH 2 ) a -O-(CH 2 ) b -, -(C=O)-O-(CF 2 ) a -O-(CF 2 ) b -, -(C=O)-O-C 6 H 4- and at least one selected from these combinations. In the formula, a, b, c, and d are each independently at least 1 or more. a, b, c, and d may each independently be 2 or more, 3 or more, 4 or more, 10 or more, or 20 or more. The upper limit of a, b, c, and d is, for example, 100.

[0515] R a Suitable specific examples as -CF 2 -O-, -CF 2 -O-CF 2 -, -CF 2 -O-CH 2 -, -CF 2 -O-CH 2 CF 2 -, -CF 2 -O-CF 2 CF 2 -, -CF 2 -O-CF 2 CH 2 -, -CF 2 -O-CF 2 CF 2 CH 2 -, -CF 2 -O-CF(CF 3 )-, -CF 2 -O-CF(CF 3 )CF 2 -, -CF 2 -O-CF(CF 3 )CF 2 -O-, -CF 2 -O-CF(CF 3 )CH 2 -, -(C=O)-, -(C=O)-O-, -(C=O)-(CH 2 )-, -(C=O)-(CF 2 )-, -(C=O)-O-(CH 2 )-, -(C=O)-O-(CF 2 )-, -(C=O)-[(CH 2 ) 2 -O] n -, -(C=O)-[(CF 2 ) 2 -O] n -, -(C=O)-O[(CH2 ) 2 -O] n -,-(C=O)-O[(CF 2 ) 2 -O] n -,-(C=O)-O[(CH 2 ) 2 -O] n -(CH 2 )-,-(C=O)-O[(CF 2 ) 2 -O] n -(CF 2 )-,-(C=O)-(CH 2 ) 2 -O-(CH 2 )-,-(C=O)-(CF 2 ) 2 -O-(CF 2 )-,-(C=O)-O-(CH 2 ) 2 -O-(CH 2 )-,-(C=O)-O-(CF 2 ) 2 -O-(CF 2 )-,-(C=O)-O-C 6 H 4 - etc. are included. Among them, the above R a is specifically, -CF 2 -O-,-CF 2 -O-CF 2 -,-CF 2 -O-CF 2 CF 2 -,-CF 2 -O-CF(CF 3 )-,-CF 2 -O-CF(CF 3 )CF 2 -,-CF 2 -O-CF(CF 3 )CF 2 -O-,-(C=O)-,-(C=O)-O-,-(C=O)-(CH 2 )-,-(C=O)-O-(CH 2 )-,-(C=O)-O[(CH 2 ) 2 -O] n -,-(C=O)-O[(CH 2 ) 2 -O]n -(CH 2 )-、-(C=O)-(CH 2 ) 2 -O-(CH 2 )-、 or -(C=O)-O-C 6 H 4 - is preferred. In the above formula, n is an integer from 1 to 10.

[0516] -R in general formula (4) a -(CZ 1 Z 2 ) k - as, -CF 2 -O-CF 2 -、-CF 2 -O-CF(CF 3 )-、-CF 2 -O-C(CF 3 ) 2 -、-CF 2 -O-CF 2 -CF 2 -、-CF 2 -O-CF 2 -CF(CF 3 )-、-CF 2 -O-CF 2 -C(CF 3 ) 2 -、-CF 2 -O-CF 2 CF 2 -CF 2 -、-CF 2 -O-CF 2 CF 2 -CF(CF 3 )-、-CF 2 -O-CF 2 CF 2 -C(CF 3 ) 2 -、-CF 2 -O-CF(CF 3 )-CF 2 -、-CF 2 -O-CF(CF 3 )-CF(CF 3 )-、-CF 2 -O-CF(CF 3 )-C(CF 3 ) 2 -、-CF2 -O-CF(CF 3 )CF 2 -CF 2 -、-CF 2 -O-CF(CF 3 )CF 2 -CF(CF 3 )-、-CF 2 -O-CF(CF 3 )CF 2 -C(CF 3 ) 2 -、-CF 2 -O-CF(CF 3 )CF 2 -O-CF 2 -、-CF 2 -O-CF(CF 3 )CF 2 -O-CF(CF 3 )-、-CF 2 -O-CF(CF 3 )CF 2 -O-C(CF 3 ) 2 -、-(C=O)-、-(C=O)-O-、-(C=O)-(CH 2 )-、-(C=O)-(CF 2 )-、-(C=O)-O-(CH 2 )-、-(C=O)-O-(CF 2 )-、-(C=O)-[(CH 2 ) 2 -O] n -(CH 2 )-、-(C=O)-[(CF 2 ) 2 -O] n -(CF 2 )-、-(C=O)-[(CH 2 ) 2 -O] n -(CH 2 )-(CH 2 )-、-(C=O)-[(CF 2 ) 2 -O] n -(CF 2 )-(CF 2 )-、-(C=O)-O[(CH 2 ) 2 -O] n -(CF 2)-, -(C=O)-O[(CH 2 ) 2 -O] n -(CH 2 )-(CH 2 )-, -(C=O)-O[(CF 2 ) 2 -O] n -(CF 2 )-, -(C=O)-O[(CF 2 ) 2 -O] n -(CF 2 )-(CF 2 )-, -(C=O)-(CH 2 ) 2 -O-(CH 2 )-(CH 2 )-, -(C=O)-(CF 2 ) 2 -O-(CF 2 )-(CF 2 )-, -(C=O)-O-(CH 2 ) 2 -O-(CH 2 )-(CH 2 )-, -(C=O)-O-(CF 2 ) 2 -O-(CF 2 )-(CF 2 )-, -(C=O)-O-(CH 2 ) 2 -O-(CH 2 )-C(CF 3 ) 2 -, -(C=O)-O-(CF 2 ) 2 -O-(CF 2 )-C(CF 3 ) 2 -, or, -(C=O)-O-C 6 H 4 -C(CF 3 ) 2 - is preferred, -CF 2 -O-CF(CF 3 )-, -CF 2 -O-CF 2 -CF(CF 3 )-, -CF 2 -O-CF 2 CF 2 -CF(CF3 )-, -CF 2 -O-CF(CF 3 )-CF(CF 3 )-, -CF 2 -O-CF(CF 3 )CF 2 -CF(CF 3 )-, -CF 2 -O-CF(CF 3 )CF 2 -O-CF(CF 3 )-, -(C=O)-, -(C=O)-O-(CH 2 )-, -(C=O)-O-(CH 2 )-(CH 2 )-, -(C=O)-O[(CH 2 ) 2 -O] n -(CH 2 )-(CH 2 )-, -(C=O)-O-(CH 2 ) 2 -O-(CH 2 )-C(CF 3 ) 2 -, or, -(C=O)-O-C 6 H 4 -C(CF 3 ) 2 - is more preferred. In the above formula, n is an integer from 1 to 10.

[0517] Specific examples of the compound represented by the general formula (4) include

Chemical formula

[0518] R a is, for example, the general formula (r1): -(C=O) h -(O) i -CF 2 -O-(CX 6 2 ) e -{O-CF(CF 3 )}f -(O) g - (r1) (In the formula, X 6 is each independently H, F or CF 3 ; e is an integer from 0 to 3; f is an integer from 0 to 3; g is 0 or 1; h is 0 or 1; i is 0 or 1), a divalent group represented by is preferred. General formula (r2): -(C=O) h -(O) i -CF 2 -O-(CX 7 2 ) e -(O) g - (r2) (In the formula, X 7 is each independently H, F or CF 3 ; e is an integer from 0 to 3; g is 0 or 1; h is 0 or 1; i is 0 or 1.), a divalent group represented by is also preferred.

[0519] -R in general formula (4) a -(CZ 1 Z 2 ) k - is also, for example, the following formula (t1): -(C=O) h -(O) i -CF 2 -O-(CX 6 2 ) e -{O-CF(CF 3 )} f -(O) g -CZ 1 Z 2 - (t1) (In the formula, X 6 is each independently H, F or CF 3 ; e is an integer from 0 to 3; f is an integer from 0 to 3; g is 0 or 1; h is 0 or 1; i is 0 or 1; Z 1 and Z 2 are each independently F or CF 3 ), a divalent group represented by is also preferred. In formula (t1), Z 1 and Z 2It is more preferable that one is F and the other is CF 3 is more preferable. Also, in the general formula (4), -R a -(CZ 1 Z 2 ) k as - is the following formula (t2): -(C=O) h -(O) i -CF 2 -O-(CX 7 2 ) e -(O) g -CZ 1 Z 2 - (t2) (wherein X 7 are each independently H, F or CF 3 and e is an integer from 0 to 3, g is 0 or 1, h is 0 or 1, i is 0 or 1, and Z 1 and Z 2 are each independently F or CF 3 ) represented by a divalent group is also preferable. In the formula (t2), Z 1 and Z 2 it is more preferable that one is F and the other is CF 3 is more preferable.

[0520] The compound represented by the general formula (4) preferably has a C-F bond and no C-H bond except for the hydrophilic group (Y 3 ). That is, in the general formula (4), X i , X j , and X k are all F, and R a is preferably a perfluoroalkylene group having 1 or more carbon atoms. The perfluoroalkylene group may be either linear or branched, either cyclic or acyclic, and may contain at least one chain heteroatom. The carbon number of the perfluoroalkylene group may be 2 to 20, or may be 4 to 18.

[0521] The compound represented by the general formula (4) may be partially fluorinated. That is, the compound represented by the general formula (4) preferably has at least one hydrogen atom bonded to a carbon atom and at least one fluorine atom bonded to a carbon atom, excluding the hydrophilic group (Y 3 ).

[0522] The compound represented by the general formula (4) is preferably a compound represented by the following formula (4a). CF 2 =CF-O-Rf 0 -Y 3 (4a) (In the formula, Y 3 is a hydrophilic group, and Rf 0 is perfluorinated and may be linear or branched, cyclic or acyclic, saturated or unsaturated, substituted or unsubstituted, and is a perfluorinated divalent linking group optionally additionally containing one or more heteroatoms selected from the group consisting of sulfur, oxygen, and nitrogen.)

[0523] The compound represented by the general formula (4) is preferably a compound represented by the following formula (4b). CH 2 =CH-O-Rf 0 -Y 3 (4b) (In the formula, Y 3 is a hydrophilic group, and Rf 0 is the perfluorinated divalent linking group defined in formula (4a).)

[0524] In the general formula (4), Y 3 is preferably one form which is -OSO 3 M. When Y 3 is -OSO 3 M, examples of the compound represented by the general formula (4) include CF 2 =CF(OCF 2 CF 2 CH 2 OSO 3 M), CH 2 =CH((CF 2 ) 4 CH 2 OSO3 M), CF 2 =CF(O(CF 2 ) 4 CH 2 OSO 3 M), CF 2 =CF(OCF 2 CF(CF 3 )CH 2 OSO 3 M), CF 2 =CF(OCF 2 CF(CF 3 )OCF 2 CF 2 CH 2 OSO 3 M), CH 2 =CH((CF 2 ) 4 CH 2 OSO 3 M), CF 2 =CF(OCF 2 CF 2 SO 2 N(CH 3 )CH 2 CH 2 OSO 3 M), CH 2 =CH(CF 2 CF 2 CH 2 OSO 3 M), CF 2 =CF(OCF 2 CF 2 CF 2 CF 2 SO 2 N(CH 3 )CH 2 CH 2 OSO 3 Examples include M), etc. In the above formula, M is the same as above.

[0525] In general formula (4), Y 3 being -SO 3 M is also one of the preferred forms. When Y 3 is -SO 3 M, examples of the compound represented by general formula (4) include CF 2 =CF(OCF 2 CF 2 SO3 M), CF 2 =CF(O(CF 2 ) 4 SO 3 M), CF 2 =CF(OCF 2 CF(CF 3 )SO 3 M), CF 2 =CF(OCF 2 CF(CF 3 )OCF 2 CF 2 SO 3 M), CH 2 =CH(CF 2 CF 2 SO 3 M), CF 2 =CF(OCF 2 CF(CF 3 )OCF 2 CF 2 CF 2 CF 2 SO 3 M), CH 2 =CH((CF 2 ) 4 SO 3 M), CH 2 =CH((CF 2 ) 3 SO 3 M), etc. may be mentioned. In the above formula, M is the same as above.

[0526] In general formula (4), Y 3 being -COOM is also one of the preferred forms. When Y 3 is -COOM, examples of the compound represented by general formula (4) include CF 2 =CF(OCF 2 CF 2 COOM), CF 2 =CF(OCF 2 CF 2 CF 2 COOM), CF 2 =CF(O(CF 2 ) 5 COOM), CF 2 =CF(OCF 2 CF(CF 3 )COOM), CF2 =CF(OCF 2 CF(CF 3 )O(CF 2 ) n COOM) (n is greater than 1), CH 2 =CH(CF 2 CF 2 COOM), CH 2 =CH((CF 2 ) 4 COOM), CH 2 =CH((CF 2 ) 3 COOM), CF 2 =CF(OCF 2 CF 2 SO 2 NR’CH 2 COOM), CF 2 =CF(O(CF 2 ) 4 SO 2 NR’CH 2 COOM), CF 2 =CF(OCF 2 CF(CF 3 )SO 2 NR’CH 2 COOM), CF 2 =CF(OCF 2 CF(CF 3 )OCF 2 CF 2 SO 2 NR’CH 2 COOM), CH 2 =CH(CF 2 CF 2 SO 2 NR’CH 2 COOM), CF 2 =CF(OCF 2 CF(CF 3 )OCF 2 CF 2 CF 2 CF 2 SO 2 NR’CH 2 COOM), CH 2 =CH((CF 2 ) 4 SO 2 NR’CH 2 COOM), CH 2=CH((CF 2 ) 3 SO 2 NR’CH 2 COOM), etc. In the above formula, R’ is H or C 1-4 alkyl group, and M is the same as above.

[0527] In general formula (4), Y 3 is -OPO 3 M or -OP(O)(OM) 2 is also one of the preferred forms. When Y 3 is -OPO 3 M or -OP(O)(OM) 2 , the compounds represented by general formula (4) include CF 2 =CF(OCF 2 CF 2 CH 2 OP(O)(OM) 2 ), CF 2 =CF(O(CF 2 ) 4 CH 2 OP(O)(OM) 2 ), CF 2 =CF(OCF 2 CF(CF 3 )CH 2 OP(O)(OM) 2 ), CF 2 =CF(OCF 2 CF(CF 3 )OCF 2 CF 2 CH 2 OP(O)(OM) 2 ), CF 2 =CF(OCF 2 CF 2 SO 2 N(CH 3 )CH 2 CH 2 OP(O)(OM) 2 ), CF 2 =CF(OCF 2 CF 2 CF 2 CF 2 SO 2 N(CH 3 )CH 2 CH2 OP(O)(OM) 2 )、CH 2 =CH(CF 2 CF 2 CH 2 OP(O)(OM) 2 、CH 2 =CH((CF 2 ) 4 CH 2 OP(O)(OM) 2 )、CH 2 =CH((CF 2 ) 3 CH 2 OP(O)(OM) 2 ) etc. may be mentioned. In the above formula, M is the same as above.

[0528] In general formula (4), Y 3 is -PO 3 M or -P(O)(OM) 2 is also one of the preferred forms. Y 3 being -PO 3 M or -P(O)(OM) 2 when it is the case, as the compound represented by general formula (4), CF 2 =CF(OCF 2 CF 2 P(O)(OM) 2 )、CF 2 =CF(O(CF 2 ) 4 P(O)(OM) 2 )、CF 2 =CF(OCF 2 CF(CF 3 )P(O)(OM) 2 )、CF 2 =CF(OCF 2 CF(CF 3 )OCF 2 CF 2 P(O)(OM) 2 )、CH 2 =CH(CF 2 CF 2 P(O)(OM) 2 )、CH 2 =CH((CF 2 ) 4 P(O)(OM) 2)、CH 2 =CH((CF 2 ) 3 P(O)(OM) 2 ) etc. may be mentioned, where M is the same as above.

[0529] As the compound represented by the general formula (4), the general formula (5): CX 2 =CY(-CZ 2 -O-Rf-Y 3 ) (5) (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, Z is the same or different and is -H, -F, an alkyl group or a fluorine-containing alkyl group. Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms, or a fluorine-containing alkylene group having an ether bond and having 2 to 100 carbon atoms. Y 3 is the same as above.) The compound represented by the general formula (6): CX 2 =CY(-O-Rf-Y 3 ) (6) (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, Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms, or a fluorine-containing alkylene group having an ether bond and having 2 to 100 carbon atoms. Y 3 is the same as above.) The compound represented by the general formula (7): CX 2 =CY(-Rf-Y 3 ) (7) (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, Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms, or a fluorine-containing alkylene group having an ether bond and having 2 to 100 carbon atoms. Y 3 is the same as above.) It is preferably at least one selected from the group consisting of the compounds represented by the above. The fluorine-containing alkylene group having an ether bond with 2 to 100 carbon atoms does not include a structure in which an oxygen atom is at the terminal, and is an alkylene group containing an ether bond between carbon atoms.

[0530] In general formula (5), X is -H or -F. Both X 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.

[0531] In general formula (5), Y is -H, -F, an alkyl group, or a fluorine-containing alkyl group. The above alkyl group is an alkyl group that does not contain a fluorine atom, and the number of carbon atoms may be 1 or more. The number of carbon atoms of the above alkyl group is preferably 6 or less, more preferably 4 or less, and still more preferably 3 or less. The above fluorine-containing alkyl group is an alkyl group that contains at least one fluorine atom, and the number of carbon atoms may be 1 or more. The number of carbon atoms of the above fluorine-containing alkyl group is preferably 6 or less, more preferably 4 or less, and still more preferably 3 or less. As the above Y, -H, -F or -CF 3 is preferable, and -F is more preferable.

[0532] In general formula (5), Z is the same or different and is -H, -F, an alkyl group or a fluoroalkyl group. The above alkyl group is an alkyl group that does not contain a fluorine atom, and the number of carbon atoms may be 1 or more. The number of carbon atoms of the above alkyl group is preferably 6 or less, more preferably 4 or less, and still more preferably 3 or less. The above fluorine-containing alkyl group is an alkyl group that contains at least one fluorine atom, and the number of carbon atoms may be 1 or more. The number of carbon atoms of the above fluorine-containing alkyl group is preferably 6 or less, more preferably 4 or less, and still more preferably 3 or less. As the above Z, -H, -F or -CF 3 is preferable, and -F is more preferable.

[0533] In general formula (5), it is preferable that at least one of X, Y, and Z contains a fluorine atom. For example, X may be -H, and Y and Z may be -F.

[0534] In general formula (5), Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms, or a fluorine-containing alkylene group having an ether bond and having 2 to 100 carbon atoms. The number of carbon atoms of the fluorine-containing alkylene group is preferably 2 or more. Also, it is preferably 30 or less, more preferably 20 or less, and still more preferably 10 or less. Examples of the fluorine-containing alkylene group include -CF 2 -, -CH 2 CF 2 -, -CF 2 CF 2 -, -CF 2 CH 2 -, -CF 2 CF 2 CH 2 -, -CF(CF 3 )-, -CF(CF 3 )CF 2 -, -CF(CF 3 )CH 2 -, etc. The fluorine-containing alkylene group is preferably a perfluoroalkylene group.

[0535] The number of carbon atoms of the fluorine-containing alkylene group having an ether bond is preferably 3 or more. Also, the number of carbon atoms of the fluorine-containing alkylene group having an ether bond is preferably 60 or less, more preferably 30 or less, and still more preferably 12 or less. Examples of the fluorine-containing alkylene group having an ether bond include, for example, the following formula:

Chemical formula

[0536] In the general formula (5), Y 3 is -COOM, -SO 3 M or -OSO 3 M (M is H, a metal atom, NR 7y4 An optionally substituted imidazolium, an optionally substituted pyridinium or an optionally substituted phosphonium, R 7y is H or an organic group, which may be the same or different. Any two of them may be bonded to each other to form a ring.) is preferred. R 7y The organic group in is preferably an alkyl group. R 7y is preferably H or an organic group of C 1-10 and more preferably H or an organic group of C 1-4 and still more preferably H or an organic group of C 1-4 The alkyl group of is still more preferred. Examples of the above metal atom include an alkali metal (Group 1), an alkaline earth metal (Group 2), etc., and Na, K or Li is preferred. M is preferably -H, a metal atom or NR 7 4 is more preferably -H, an alkali metal (Group 1), an alkaline earth metal (Group 2) or NR 7 4 is still more preferably -H, -Na, -K, -Li or NH 4 is still more preferably -H, -Na, -K or NH 4 is even more preferably -H, -Na or NH 4 is particularly preferably -H or -NH 4 is most preferably. The above Y 3 is preferably -COOM or -SO 3 M, and -COOM is more preferred.

[0537] The compound represented by the general formula (5) is preferably the compound (5a) represented by the general formula (5a). CH 2 =CF(-CF 2 -O-Rf-Y 3 ) (5a) (In the formula, Rf and Y 3 are the same as above.)

[0538] Specific examples of the compound represented by the general formula (5a) include the following formula

[0539]

Chem.

[0540] (wherein, Z 1 is F or CF 3 ; Z 2 and Z 3 are each H or F; Z 4 is H, F or CF 3 ; p1 + q1 + r1 is an integer from 0 to 10; s1 is 0 or 1; t1 is an integer from 0 to 5, Y 3 is the same as above. However, when both Z 3 and Z 4 are H, p1 + q1 + r1 + s1 is not 0) compounds represented by are included. More specifically,

[0541]

Chem.

[0542] etc. are preferably included, and among them

[0543]

Chem.

[0544] is preferably the case.

[0545] As the compound represented by the general formula (5a), it is preferable that Y 3 in the formula (5a) is -COOM, and in particular, CH 2 =CFCF 2 OCF(CF 3 )COOM, and CH 2 =CFCF 2 OCF(CF 3 )CF 2 OCF(CF 3 )COOM (wherein, M is the same as defined above.) at least one selected from the group consisting of is preferable, CH 2 =CFCF2 OCF(CF 3 )COOM is more preferable.

[0546] The compound represented by the general formula (5) is preferably the compound (5b) represented by the general formula (5b). CX 2 2 =CFCF 2 -O-(CF(CF 3 )CF 2 O) n5 -CF(CF 3 )-Y 3 (5b) (In the formula, each X 2 is the same and represents F or H. n5 represents 0 or an integer from 1 to 10, and Y 3 is as defined above.)

[0547] In the above formula (5b), n5 is preferably 0 or an integer from 1 to 5, more preferably 0, 1 or 2, and even more preferably 0 or 1, in terms of the stability of the resulting aqueous dispersion. The above Y 3 is preferably -COOM in terms of obtaining appropriate water solubility and stability of the aqueous dispersion. The above M is preferably H or NH 4 in terms of being difficult to remain as an impurity and improving the heat resistance of the obtained molded body.

[0548] Examples of the compound represented by the above formula (5b) include CH 2 =CFCF 2 OCF(CF 3 )COOM, CH 2 =CFCF 2 OCF(CF 3 )CF 2 OCF(CF 3 )COOM (where M is as defined above).

[0549] In addition, examples of the compound represented by the general formula (5) include the compound represented by the general formula (5c).

[0550] CF2 =CFCF 2 -O-Rf-Y 3 (5c) (wherein, Rf and Y 3 are the same as defined above)

[0551] More specifically, [Chemical formula] etc. may be mentioned.

[0552] In general formula (6), X is -H or -F. Both X's may be -F, or at least one of them may be -H. For example, one of them may be -F and the other may be -H, or both may be -H.

[0553] In general formula (6), Y is -H, -F, an alkyl group or a fluorine-containing alkyl group. The above alkyl group is an alkyl group that does not contain a fluorine atom, and the number of carbon atoms may be 1 or more. The number of carbon atoms of the above alkyl group is preferably 6 or less, more preferably 4 or less, and still more preferably 3 or less. The above fluorine-containing alkyl group is an alkyl group that contains at least one fluorine atom, and the number of carbon atoms may be 1 or more. The number of carbon atoms of the above fluorine-containing alkyl group is preferably 6 or less, more preferably 4 or less, and still more preferably 3 or less. As the above Y, -H, -F or -CF 3 is preferable, and -F is more preferable.

[0554] In general formula (6), it is preferable that at least one of the above X and Y contains a fluorine atom. For example, X may be -H, and Y and Z may be -F.

[0555] In general formula (6), the above Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms, or a fluorine-containing alkylene group having an ether bond and having 2 to 100 carbon atoms. The number of carbon atoms in the above-mentioned fluorine-containing alkylene group is preferably 2 or more. Further, the number of carbon atoms in the fluorine-containing alkylene group is preferably 30 or less, more preferably 20 or less, and still more preferably 10 or less. Examples of the above-mentioned fluorine-containing alkylene group include -CF 2 -, -CH 2 CF 2 -, -CF 2 CF 2 -, -CF 2 CH 2 -, -CF 2 CF 2 CH 2 -, -CF(CF 3 )-, -CF(CF 3 )CF 2 -, -CF(CF 3 )CH 2 -, etc. The above-mentioned fluorine-containing alkylene group is preferably a perfluoroalkylene group.

[0556] In the above general formula (6), Y 3 is preferably -COOM, -SO 3 M or -OSO 3 M (where M is H, a metal atom, NR 7y 4 , an optionally substituted imidazolium, an optionally substituted pyridinium or an optionally substituted phosphonium, R 7y is H or an organic group, and they may be the same or different. Any two of them may be bonded to each other to form a ring.). As the organic group of R 7y , an alkyl group is preferred. As R 7y , H or an organic group of C 1-10 is preferred, H or an organic group of C 1-4 is more preferred, and H or an alkyl group of C 1-4 is still more preferred. Examples of the above-mentioned metal atom include alkali metals (Group 1), alkaline earth metals (Group 2), etc., and Na, K or Li is preferred. As M, -H, a metal atom or NR 7 4is preferred, -H, an alkali metal (Group 1), an alkaline earth metal (Group 2) or NR 7 4 is more preferred, -H, -Na, -K, -Li or NH 4 is still more preferred, -H, -Na, -K or NH 4 is still more preferably, -H, -Na or NH 4 is particularly preferred, -H or -NH 4 is most preferred. Said Y 3 is, -COOM or -SO 3 M is preferred, -COOM is more preferred.

[0557] The compound represented by the general formula (6) is preferably at least one selected from the group consisting of the compounds represented by the general formulas (6a), (6b), (6c), (6d) and (6e). CF 2 =CF-O-(CF 2 ) n1 -Y 3 (6a) (In the formula, n1 represents an integer from 1 to 10, and Y 3 is as defined above.) CF 2 =CF-O-(CF 2 C(CF 3 )F) n2 -Y 3 (6b) (In the formula, n2 represents an integer from 1 to 5, and Y 3 is as defined above.) CF 2 =CF-O-(CFX 1 ) n3 -Y 3 (6c) (In the formula, X 1 is F or CF 3 and represents, n3 represents an integer from 1 to 10, and Y 3 is as defined above.) CF 2 =CF-O-(CF 2 CFX 1 O) n4 -(CF 2 ) n6 -Y3 (6d) (wherein, n4 represents an integer of 1 to 10, n6 represents an integer of 1 to 3, Y 3 and X 1 are the same as defined above.) CF 2 =CF-O-(CF 2 CF 2 CFX 1 O) n5 -CF 2 CF 2 CF 2 -Y 3 (6e) (wherein, n5 represents an integer of 0 to 10, Y 3 and X 1 are the same as defined above.)

[0558] In the above formula (6a), it is preferable that the above n1 is an integer of 5 or less, and more preferably an integer of 2 or less. The above Y 3 is preferably -COOM in terms of obtaining appropriate water solubility and stability of the aqueous dispersion, M is less likely to remain as an impurity, and H or NH 4 is preferably used in terms of improving the heat resistance of the obtained molded body.)

[0559] Examples of the compound represented by the above formula (6a) include CF 2 =CF-O-CF 2 COOM, CF 2 =CF(OCF 2 CF 2 COOM), CF 2 =CF(OCF 2 CF 2 CF 2 COOM) (wherein, M is the same as defined above).

[0560] In the above formula (6b), it is preferable that the above n2 is an integer of 3 or less in terms of the stability of the obtained aqueous dispersion, and Y 3 is preferably -COOM in terms of obtaining appropriate water solubility and stability of the aqueous dispersion, M is less likely to remain as an impurity, and H or NH4 is preferably.

[0561] In the above formula (6c), n3 is preferably an integer of 5 or less in terms of water solubility, and Y 3 is preferably -COOM in terms of obtaining appropriate water solubility and stability of the aqueous dispersion, and M is preferably H or NH 4 is preferably.

[0562] In the above formula (6d), X 1 is preferably -CF 3 in terms of the stability of the aqueous dispersion, n4 is preferably an integer of 5 or less in terms of water solubility, and Y 3 is preferably -COOM in terms of obtaining appropriate water solubility and stability of the aqueous dispersion, and M is preferably H or NH 4 is preferably.

[0563] Examples of the compound represented by the above formula (6d) include CF 2 =CFOCF 2 CF(CF 3 )OCF 2 CF 2 COOM, CF 2 =CFOCF 2 CF(CF 3 )OCF 2 COOM, CF 2 =CFOCF 2 CF(CF 3 )OCF 2 CF 2 CF 2 COOM (wherein M represents H, NH 4 or an alkali metal).

[0564] In the general formula (6e), n5 is preferably an integer of 5 or less in terms of water solubility, and Y 3 is preferably -COOM in terms of obtaining appropriate water solubility and stability of the aqueous dispersion, and M is preferably H or NH 4 is preferably.

[0565] Examples of the compound represented by the general formula (6e) include CF 2 =CFOCF 2 CF 2 CF 2 COOM (wherein M represents H, NH 4 or an alkali metal).

[0566] In the general formula (7), Rf is preferably a fluorine-containing alkylene group having 1 to 40 carbon atoms. In the general formula (7), at least one of X and Y preferably contains a fluorine atom.

[0567] The compound represented by the general formula (7) is a compound represented by the general formula (7a): CF 2 =CF-(CF 2 ) n1 -Y 3 (7a) (wherein n1 represents an integer of 1 to 10, and Y 3 is the same as defined above), and a compound represented by the general formula (7b): CF 2 =CF-(CF 2 C(CF 3 )F) n2 -Y 3 (7b) (wherein n2 represents an integer of 1 to 5, and Y 3 is the same as defined above), and at least one selected from the group consisting of compounds represented by the formula is preferred. The above Y 3 is preferably -SO 3 M or -COOM, and M is preferably H, a metal atom, NR 7y 4 , imidazolium which may have a substituent, pyridinium which may have a substituent, or phosphonium which may have a substituent. The above R 7y represents H or an organic group.

[0568] In the above formula (7a), the above n1 is preferably an integer of 5 or less, and more preferably an integer of 2 or less. The above Y 3In terms of obtaining appropriate water solubility and stability of the aqueous dispersion, it is preferably -COOM, and M is difficult to remain as an impurity, and in terms of improving the heat resistance of the obtained molded article, it is H or NH 4 is preferably. Examples of the compound represented by the above formula (7a) include CF 2 =CFCF 2 COOM (wherein M is the same as defined above).

[0569] In the above formula (7b), n2 is preferably an integer of 3 or less in terms of the stability of the obtained aqueous dispersion, and Y 3 is preferably -COOM in terms of obtaining appropriate water solubility and stability of the aqueous dispersion, M is difficult to remain as an impurity, and in terms of improving the heat resistance of the obtained molded article, it is H or NH 4 is preferably.

[0570] The above modified monomer preferably contains a modified monomer (A), and preferably contains at least one selected from the group consisting of compounds represented by general formula (5a), general formula (5c), general formula (6a), general formula (6b), general formula (6c), and general formula (6d), and more preferably contains a compound represented by general formula (5a) or general formula (5c).

[0571] When using the modified monomer (A) as the modified monomer, the content of the modified monomer (A) unit is preferably in the range of 0.00001 to 1.0% by mass based on the total polymerization units of the above TFE polymer (PTFE). As the lower limit, 0.0001% by mass is more preferable, 0.0005% by mass is more preferable, 0.001% by mass is still more preferable, and 0.005% by mass is still more preferable. As the upper limit, in order of preference, they are 0.90% by mass, 0.50% by mass, 0.40% by mass, 0.30% by mass, 0.20% by mass, 0.15% by mass, 0.10% by mass, 0.08% by mass, 0.05% by mass, 0.01% by mass.

[0572] In the production of the above TFE polymer, the polymer (I) can be used within the range of use in the production method of the present disclosure described above. The concentration of the polymer (I) is not particularly limited as long as it is within the above range. If the addition amount is too large, acicular particles with a large aspect ratio are generated, and the aqueous dispersion becomes gel-like and its stability is impaired. The lower limit of the usage amount of the polymer (I) is preferably 0.0001% by mass, more preferably 0.001% by mass, still more preferably 0.01% by mass, and particularly preferably 0.02% by mass with respect to the aqueous medium. The upper limit of the usage amount of the above polymer (I) is preferably 10% by mass, more preferably 5% by mass with respect to the aqueous medium.

[0573] The polymer (I) may be added to the reaction vessel all at once before the start of polymerization, may be added all at once after the start of polymerization, may be added in a plurality of divided portions during polymerization, or may be added continuously during polymerization.

[0574] In the production of the above TFE polymer, as the polymerization initiator, persulfates (for example, ammonium persulfate), organic peroxides such as disuccinic peroxide and diglutaric peroxide can be used alone or in the form of a mixture thereof. Further, it may be used in a redox system in combination with a reducing agent such as sodium sulfite. Furthermore, during polymerization, a radical scavenger such as hydroquinone or catechol can be added, or a peroxide decomposer such as ammonium sulfite can be added to adjust the radical concentration in the system.

[0575] As the redox polymerization initiator, it is preferable to use a redox initiator that combines an oxidizing agent and a reducing agent. Examples of the oxidizing agent include persulfates, organic peroxides, potassium permanganate, manganese triacetate, ammonium cerium nitrate, etc. Examples of the reducing agent include sulfites, bisulfites, bromates, diimines, oxalic acid, etc. Examples of the persulfate include ammonium persulfate and potassium persulfate. Examples of the sulfite include sodium sulfite and ammonium sulfite. To increase the decomposition rate of the initiator, it is also preferable to add a copper salt or an iron salt to the combination of the redox initiator. Examples of the copper salt include copper(II) sulfate, and examples of the iron salt include iron(II) sulfate.

[0576] Examples of the redox initiator include, for example, potassium permanganate / oxalic acid, ammonium persulfate / bisulfite / iron sulfate, manganese triacetate / oxalic acid, ammonium cerium nitrate / oxalic acid, bromate / bisulfite, etc., and potassium permanganate / oxalic acid is preferable. When using a redox initiator, either the oxidizing agent or the reducing agent may be charged into the polymerization tank in advance, and then the other may be added continuously or intermittently to initiate the polymerization. For example, when using potassium permanganate / oxalic acid, it is preferable to charge oxalic acid into the polymerization tank and continuously add potassium permanganate thereto.

[0577] In the production of the above TFE polymer, known chain transfer agents can be used. For example, saturated hydrocarbons such as methane, ethane, propane, butane, etc., halogenated hydrocarbons such as chloromethane, dichloromethane, difluoroethane, etc., alcohols such as methanol, ethanol, isopropanol, etc., hydrogen, etc. can be mentioned, and those in a gaseous state at normal temperature and pressure are preferable.

[0578] The amount of the chain transfer agent used is usually 1 to 10,000 mass ppm, preferably 1 to 5,000 mass ppm, based on the total amount of TFE supplied.

[0579] In the production of the above TFE polymer, furthermore, as a dispersion stabilizer for the reaction system, a saturated hydrocarbon having 12 or more carbon atoms that is substantially inert to the reaction and becomes liquid under the above reaction conditions can also be used in an amount of 2 to 10 parts by mass with respect to 100 parts by mass of the aqueous medium. Also, ammonium carbonate, ammonium phosphate, etc. may be added as a buffer for adjusting the pH during the reaction.

[0580] When the polymerization of TFE is completed, a polymerization dispersion liquid having a solid content concentration of 1.0 to 50% by mass and an average primary particle diameter of 50 to 500 nm can be obtained. The lower limit of the above solid content concentration is preferably 5% by mass, more preferably 8% by mass. The upper limit is not particularly limited, but may be 40% by mass or 35% by mass. The lower limit of the above average primary particle diameter is preferably 100 nm, more preferably 150 nm. The upper limit is preferably 400 nm, more preferably 350 nm. The above average primary particle diameter can be measured by the dynamic light scattering method. The above average primary particle diameter can be measured by preparing an aqueous dispersion adjusted to a solid content concentration of about 1.0% by mass, using the dynamic light scattering method, at 25°C, with the refractive index of the solvent (water) being 1.3328, the viscosity of the solvent (water) being 0.8878 mPa·s, and integrating 70 times. As the dynamic light scattering method, for example, ELSZ-1000S (manufactured by Otsuka Electronics Co., Ltd.) can be used.

[0581] Fine powder can be produced by coagulating an aqueous dispersion of a TFE polymer. The aqueous dispersion of the TFE polymer can be used for various purposes as a fine powder after coagulation, washing, and drying. When coagulating the aqueous dispersion of the TFE polymer, usually, an aqueous dispersion obtained by polymerization such as a polymer latex is diluted with water to a polymer concentration of 5 to 20% by mass, and in some cases, after adjusting the pH to neutral or alkaline, it is stirred more vigorously than during the reaction in a container equipped with a stirrer. The above coagulation may be carried out while adding a water-soluble organic compound such as methanol or acetone, an inorganic salt such as potassium nitrate or ammonium carbonate, or an inorganic acid such as hydrochloric acid, sulfuric acid, or nitric acid as a coagulant. The above coagulation may also be carried out continuously using an in-line mixer or the like.

[0582] From the viewpoint of productivity, the concentration of the uncoagulated TFE polymer in the wastewater generated by the above aggregation is preferably low, more preferably less than 0.4% by mass, and particularly preferably less than 0.3% by mass.

[0583] By adding a pigment for coloring or various fillers for improving mechanical properties before or during the above coagulation, a pigment-containing or filler-containing TFE polymer fine powder with the pigment and filler uniformly mixed can be obtained.

[0584] The drying of the wet powder obtained by coagulating the aqueous dispersion of the TFE polymer is usually carried out using means such as vacuum, high frequency, or hot air while keeping the wet powder in a state where it does not flow much, preferably in a static state. Friction between powders, especially at high temperatures, generally has an unfavorable effect on fine powder-type TFE polymers. This is because particles composed of this type of TFE polymer have the property of easily fibrillating even by a small shear force and losing the original stable particle structure state.

[0585] The above drying is carried out at a drying temperature of 10 to 300°C, preferably 100 to 300°C.

[0586] The resulting TFE polymer fine powder is preferable for molding, and suitable applications include hydraulic systems, fuel systems such as those in aircraft and automobiles, tubes, etc., flexible hoses for chemical solutions, steam, etc., and wire coating applications.

[0587] The aqueous dispersion of the TFE polymer can also be stabilized and further concentrated by adding a nonionic surfactant, and can be preferably used for various applications as a composition with an organic or inorganic filler added according to the purpose. By coating the above composition on a substrate made of metal or ceramics, a coating film surface having non-stickiness and a low friction coefficient can be obtained, which is excellent in gloss, smoothness, abrasion resistance, weather resistance, and heat resistance, and is suitable for coating of rolls, cooking utensils, etc., and impregnation of glass cloth.

[0588] An organosol of the TFE polymer can also be prepared from the above aqueous dispersion. The above organosol can contain the above TFE polymer and an organic solvent. Examples of the organic solvent include ether solvents, ketone solvents, alcohol solvents, amide solvents, ester solvents, aliphatic hydrocarbon solvents, aromatic hydrocarbon solvents, and halogenated hydrocarbon solvents, and N-methyl-2-pyrrolidone, dimethylacetamide, etc. can be preferably used. The preparation of the above organosol can be carried out, for example, by the method described in International Publication No. 2012 / 002038.

[0589] The aqueous dispersion of the TFE polymer or the TFE polymer fine powder is also preferably used as a processing aid. When used as a processing aid, by mixing the above aqueous dispersion or the fine powder with a host polymer, etc., the melt strength during the melt processing of the host polymer can be improved, and the mechanical strength, electrical properties, flame retardancy, dripping prevention property during combustion, and slidability of the obtained polymer can be improved.

[0590] The aqueous dispersion of the TFE polymer or the TFE polymer fine powder is also preferably used as a binder for batteries and for dust prevention applications.

[0591] The aqueous dispersion of the above TFE polymer or the above TFE polymer fine powder is also preferably used as a processing aid after being compounded with a resin other than the TFE polymer. The above aqueous dispersion or the above fine powder is suitable as a raw material for PTFE described in, for example, JP-A-11-49912, US Patent No. 5,804,654, JP-A-11-29679, and JP-A-2003-2980. The processing aid using the above aqueous dispersion or the above fine powder is not inferior to the processing aids described in the above respective publications at all.

[0592] The aqueous dispersion of the above TFE polymer is also preferably made into a co-precipitated powder by mixing with an aqueous dispersion of a melt-processable fluororesin and coagulating. The above co-precipitated powder is suitable as a processing aid.

[0593] Examples of the above melt-processable fluororesin include FEP, PFA, TFE / perfluoroallyl ether copolymer, ETFE, ethylene / TFE / HFP copolymer [EFEP], etc. Among them, PFA or FEP is preferable.

[0594] The above aqueous dispersion preferably contains the above melt-processable fluororesin. Examples of the above melt-processable fluororesin include FEP, PFA, TFE / perfluoroallyl ether copolymer, ETFE, EFEP, etc. The above aqueous dispersion containing the above melt-processable fluororesin can be used as a paint. Since the above melt-processable fluororesin can sufficiently fuse the particles of the above TFE polymer together, it can improve the film-forming property and give gloss to the resulting film.

[0595] The fluorine-free resin to which the above co-precipitated powder is added may be in powder form, pellet form, or emulsion form. The above addition is preferably carried out while applying a shearing force by a known method such as extrusion kneading or roll kneading in terms of sufficiently mixing each resin.

[0596] The aqueous dispersion of the above TFE polymer is also preferably used as a dust suppression treatment agent. The above dust suppression treatment agent can be used in methods such as mixing with a dust-generating substance and subjecting the mixture to a compression-shearing action at a temperature of 20 to 200 °C to fibrillate the TFE polymer to suppress the dust of the dust-generating substance, for example, the methods described in Japanese Patent No. 2827152, Japanese Patent No. 2538783, etc. The aqueous dispersion of the above TFE polymer can be preferably used, for example, in the dust suppression treatment agent composition described in International Publication No. 2007 / 004250, and can also be preferably used in the dust suppression treatment method described in International Publication No. 2007 / 000812.

[0597] The above dust suppression treatment agent is preferably used for dust suppression treatment in the fields of building materials, soil stabilizers, solidifying agents, fertilizers, landfilling of incineration ash and harmful substances, explosion protection, cosmetics, and sand for pet excrement such as cat litter.

[0598] The aqueous dispersion of the above TFE polymer is also preferably used as a raw material for obtaining TFE polymer fibers by the dispersion spinning method. The above dispersion spinning method is a method of mixing the aqueous dispersion of the above TFE polymer and the aqueous dispersion of a matrix polymer, extruding the mixture to form an intermediate fiber structure, and firing the intermediate fiber structure to decompose the above matrix polymer and sinter the TFE polymer particles to obtain TFE polymer fibers.

[0599] The high molecular weight PTFE powder obtained by polymerization has stretchability and non-melting processability, and is also useful as a raw material for a stretched body (porous body). When this stretched body is a film (PTFE stretched film or PTFE porous film), it can be stretched by a known PTFE stretching method. By stretching, the high molecular weight PTFE is easily fibrillated to form a PTFE porous body (film) composed of nodules and fibers. Preferably, a uniaxially stretched film can be obtained by roll-stretching a sheet-like or rod-like paste extrudate in the extrusion direction. Furthermore, a biaxially stretched film can also be obtained by stretching in the width direction using a tenter or the like. It is also preferable to perform a semi-firing treatment before stretching.

[0600] This PTFE stretched body is a porous body with a high porosity and can be suitably used as a filter medium for various precision filtration filters such as air filters and chemical solution filters, and a support material for polymer electrolyte membranes. It is also useful as a material for products used in the fiber field, medical field, electro-chemical field, sealing material field, air filtration field, ventilation / internal pressure adjustment field, liquid filtration field, general consumer goods field, etc. Specific applications are exemplified below.

[0601] Electro-chemical field Dielectric material prepregs, EMI shielding materials, heat transfer materials, etc. More specifically, printed wiring boards, electromagnetic shielding materials, insulating heat transfer materials, insulating materials, etc. Sealing material field Gaskets, packings, pump diaphragms, pump tubes, aircraft sealing materials, etc.

[0602] Air filtration field ULPA filters (for semiconductor manufacturing), HEPA filters (for hospitals and semiconductor manufacturing), cylindrical cartridge filters (for industrial use), bag filters (for industrial use), heat-resistant bag filters (for exhaust gas treatment), heat-resistant pleated filters (for exhaust gas treatment), SINBRAN filters (for industrial use), catalyst filters (for exhaust gas treatment), filters with adsorbents (for HDD integration), vent filters with adsorbents (for HDD integration), vent filters (for other HDD integration), vacuum cleaner filters (for vacuum cleaners), general-purpose multilayer felt materials, GT cartridge filters (for GT-compatible products), cooling filters (for electronic equipment enclosures), etc.

[0603] Ventilation / internal pressure adjustment field Freeze-drying materials for containers and the like for freeze-drying, automotive ventilation materials for electronic circuits and lamps, container applications for container caps and the like, protective ventilation applications for electronic devices including small terminals such as tablet terminals and mobile phone terminals, medical ventilation applications, etc.

[0604] Liquid filtration field Semiconductor liquid filtration filters (for semiconductor manufacturing), hydrophilic PTFE filters (for semiconductor manufacturing), filters for chemicals (for chemical solution treatment), filters for pure water production lines (for pure water production), backwash type liquid filtration filters (for industrial wastewater treatment), etc.

[0605] General consumer goods field Clothing, cable guides (movable wires for motorcycles), motorcycle clothing, cast liners (medical supporters), vacuum cleaner filters, bug pipes (musical instruments), cables (signal cables for guitars, etc.), strings (for stringed instruments), etc.

[0606] Fiber field PTFE fibers (fiber materials), sewing threads (textiles), weaving threads (textiles), ropes, etc.

[0607] Medical field Implants (extended products), artificial blood vessels, catheters, general surgery (tissue reinforcement materials), head and neck products (dura mater substitutes), oral health (tissue regeneration medicine), orthopedics (bandages), etc.

[0608] By the manufacturing method of the present disclosure, low molecular weight PTFE can also be manufactured. Low molecular weight PTFE may be manufactured by polymerization, or may be manufactured by reducing the molecular weight of high molecular weight PTFE obtained by polymerization by a known method (thermal decomposition, radiation irradiation decomposition, etc.).

[0609] Low-molecular-weight PTFE with a molecular weight of 600,000 or less (also called PTFE micropowder) is excellent in chemical stability, has an extremely low surface energy, and is less likely to fibrillate. Therefore, as an additive for the purpose of improving slipperiness, the texture of the coating film surface, etc., it is suitable for the manufacture of plastics, inks, cosmetics, paints, greases, office automation equipment parts, toners, etc. (see, for example, Japanese Patent Laid-Open No. 10-147617).

[0610] Further, in the presence of a chain transfer agent, a polymerization initiator and a polymer (I) may be dispersed in an aqueous medium, and TFE, or a monomer copolymerizable with TFE and TFE may be polymerized to obtain low-molecular-weight PTFE. In this case, as the chain transfer agent, at least one selected from the group consisting of alkanes having 2 to 4 carbon atoms is preferable. Specifically, methane, ethane, propane, butane, and isobutane are more preferable, and ethane and propane are even more preferable. In this case, the amount of the chain transfer agent is preferably 10 mass ppm or more or more than 10 mass ppm with respect to the aqueous medium.

[0611] When the low-molecular-weight PTFE obtained by the above polymerization is used as a powder, the aqueous dispersion can be coagulated to obtain powder particles.

[0612] In the present disclosure, high-molecular-weight PTFE means PTFE having non-melt processability and fibrillability. On the other hand, low-molecular-weight PTFE means PTFE having melt processability and not having fibrillability.

[0613] The above non-melt processability means the property that the melt flow rate cannot be measured at a temperature higher than the crystallization melting point in accordance with ASTM D 1238 and D 2116.

[0614] The presence or absence of fibrillation properties can be determined by "paste extrusion", which is a typical method for molding "high molecular weight PTFE powder", a powder made from a TFE polymer. Usually, paste extrusion is possible because high molecular weight PTFE has fibrillation properties. If the unfired molded product obtained by paste extrusion has no substantial strength or elongation, for example, if the elongation is 0% and it breaks when pulled, it can be regarded as having no fibrillation properties.

[0615] The above high molecular weight PTFE preferably has a standard specific gravity (SSG) of 2.130 to 2.280. The above standard specific gravity is measured by the water displacement method in accordance with ASTM D 792 using a sample molded in accordance with ASTM D4895-89. In the present disclosure, "high molecular weight" means that the above standard specific gravity is within the above range.

[0616] The above low molecular weight PTFE has a melt viscosity at 380 °C of 1×10 2 ~7×10 5 Pa·s. In the present disclosure, "low molecular weight" means that the above melt viscosity is within the above range. The melt viscosity is measured in accordance with ASTM D 1238 using a flow tester (manufactured by Shimadzu Corporation) and a 2φ-8L die, and maintaining a 2 g sample pre-heated at 380 °C for 5 minutes at the above temperature under a load of 0.7 MPa.

[0617] The above high molecular weight PTFE has a much higher melt viscosity than the above low molecular weight PTFE, and it is difficult to measure its exact melt viscosity. On the other hand, although the melt viscosity of the above low molecular weight PTFE can be measured, it is difficult to obtain a molded product that can be used for measuring the standard specific gravity from the above low molecular weight PTFE, and it is difficult to measure its exact standard specific gravity. Therefore, in the present disclosure, the standard specific gravity is adopted as an index of the molecular weight of the above high molecular weight PTFE, and the melt viscosity is adopted as an index of the molecular weight of the above low molecular weight PTFE. Note that for both the above high molecular weight PTFE and the above low molecular weight PTFE, there is no known measurement method that can directly specify the molecular weight.

[0618] The above high molecular weight PTFE preferably has a peak temperature of 333 to 347°C, more preferably 335 to 345°C. The above low molecular weight PTFE preferably has a peak temperature of 322 to 333°C, more preferably 324 to 332°C. The peak temperature can be specified as the temperature corresponding to the maximum value appearing in the differential thermal (DTA) curve obtained by heating PTFE without a heating history at a temperature of 300°C or higher at a rate of 10°C / min using a TG / DTA (simultaneous differential thermal and thermogravimetric analyzer).

[0619] The peak temperature of PTFE may be 322 to 347°C. When PTFE is high molecular weight PTFE, the upper limit of the peak temperature of PTFE may be 347°C or lower, 346°C or lower, 345°C or lower, 344°C or lower, 343°C or lower, 342°C or lower, 341°C or lower, 340°C or lower. When PTFE is high molecular weight PTFE, the lower limit of the peak temperature of PTFE may be 333°C or higher, 335°C or higher. When PTFE is low molecular weight PTFE, the upper limit of the peak temperature of PTFE may be 333°C or lower, 332°C or lower. When PTFE is low molecular weight PTFE, the lower limit of the peak temperature of PTFE may be 322°C or higher, 324°C or higher.

[0620] The average primary particle diameter of the primary particles of the low molecular weight PTFE is preferably 10 to 200 nm, more preferably 20 nm or more, more preferably 140 nm or less, still more preferably 150 nm or less, and particularly preferably 90 nm or less. A relatively small average primary particle diameter of the primary particles can be obtained, for example, by adding a modified monomer to the polymerization system at the initial stage of the polymerization of TFE.

[0621] The average primary particle diameter of the primary particles of low molecular weight PTFE can be measured by the dynamic light scattering method. First, a low molecular weight PTFE aqueous dispersion with a polymer solid content concentration adjusted to about 1.0% by mass is prepared, and using the dynamic light scattering method, the measurement temperature is 25 °C, the refractive index of the solvent (water) is 1.3328, the viscosity of the solvent (water) is 0.8878 mPa·s, and the number of integrated measurements is 70 times, and the measurement can be carried out. In the dynamic light scattering method, for example, ELSZ-1000S (manufactured by Otsuka Electronics Co., Ltd.) can be used.

[0622] Regarding the above high molecular weight PTFE, in the melting heat curve when the temperature is raised at a rate of 10 °C / min using a differential scanning calorimeter [DSC] for PTFE without a heating history at a temperature of 300 °C or higher, at least one endothermic peak appears in the range of 333 to 347 °C, and it is preferable that the melting heat quantity in the range of 290 to 350 °C calculated from the above melting heat curve is 52 mJ / mg or more. The melting heat quantity of PTFE is more preferably 55 mJ / mg or more, and still more preferably 58 mJ / mg or more.

[0623] An unfired tape (green tape) can also be obtained from the PTFE fine powder obtained above.

[0624] (II) Melt-processable fluororesin (1) In the production method of the present disclosure, the polymerization of FEP is preferably carried out at a polymerization temperature of 10 to 150 °C and a polymerization pressure of 0.3 to 6.0 MPaG.

[0625] The preferred monomer composition (mass %) of FEP is TFE:HFP = (60 to 95):(5 to 40), more preferably (85 to 92):(8 to 15).

[0626] In addition to TFE and HFP, a copolymer of TFE, HFP, and other monomers may be obtained as FEP by polymerizing other monomers copolymerizable with these monomers. Examples of other monomers include the fluorine-containing monomers described above (excluding TFE and HFP) and fluorine-free monomers. One or more kinds of other monomers can be used. As other monomers, perfluoro(alkyl vinyl ether) is preferable. The content of other monomer units in FEP may be 0.1 to 2% by mass based on all monomer units.

[0627] In the polymerization of the above FEP, the polymer (I) can be used within the range of use in the production method of the present disclosure, but usually, it is added in an amount of 0.0001 to 10% by mass based on 100% by mass of the aqueous medium.

[0628] In the polymerization of the above FEP, as the chain transfer agent, it is preferable to use cyclohexane, methanol, ethanol, propanol, ethane, propane, butane, pentane, hexane, carbon tetrachloride, chloroform, methylene chloride, methyl chloride, etc., and as the pH buffer, it is preferable to use ammonium carbonate, disodium hydrogen phosphate, etc.

[0629] After subjecting the aqueous dispersion of FEP obtained by the production method of the present disclosure to post-treatment such as concentration as necessary, it may be dried, made into powder, and then pelletized by melt extrusion. The aqueous medium in the aqueous dispersion of FEP may contain additives such as nonionic surfactants as necessary, may contain water-soluble organic solvents such as water-soluble alcohols, or may not contain water-soluble organic solvents.

[0630] Also, the melt extrusion can be carried out by appropriately setting the extrusion conditions as long as they are generally pelletizable extrusion conditions.

[0631] In the production method of the present disclosure, the obtained FEP has -CF at at least one of the polymer main chain and the polymer side chain. 3 、-CF 2It may have terminal groups such as H, but -COOH, -CH 2 OH, -COF, -CF=CF-, -CONH 2 , -COOCH 3 It is preferable that the content of thermally unstable groups such as etc. (hereinafter referred to as "unstable terminal groups") is low or absent.

[0632] Since the above unstable terminal groups are chemically unstable, they not only reduce the heat resistance of the resin but also cause an increase in the attenuation of the obtained electric wire.

[0633] In the production method of the present disclosure, the polymer at the end of polymerization is preferably produced so that the total number of unstable terminal groups and -CF 2 H terminal groups is 50 or less per 1×10 6 carbon atoms. More preferably, it is less than 20 per 1×10 6 carbon atoms, and even more preferably 5 or less. The above unstable terminal groups and -CF 2 H terminal groups may not be present and all may be -CF 3 terminal groups.

[0634] Unstable terminal groups and -CF 2 H terminal groups can be converted into -CF 3 terminal groups by fluorination treatment to be stabilized. The fluorination treatment method is not particularly limited, and examples include a method of exposing the polymer to a fluorine radical source that generates fluorine radicals under fluorination treatment conditions. Examples of the above fluorine radical source include fluorine gas, CoF 3 , AgF 2 , UF 6 , OF 2 , N 2 F 2 , CF 3 OF, and halogen fluorides such as IF 5 , ClF 3Examples include the above. Among these, a method of directly contacting fluorine gas with the FEP obtained by the production method of the present disclosure is preferred. In terms of reaction control, the above contact is preferably carried out using a diluted fluorine gas with a fluorine gas concentration of 10 to 50% by mass. The above diluted fluorine gas can be obtained by diluting fluorine gas with an inert gas such as nitrogen gas or argon gas. The above fluorine gas treatment can be carried out, for example, at a temperature of 100 to 250°C. Note that the treatment temperature is not limited to the above range and can be appropriately set according to the situation. The above fluorine gas treatment is preferably carried out by continuously or intermittently supplying the diluted fluorine gas into the reactor. This fluorination treatment can be either the dried powder after polymerization or the melt-extruded pellets.

[0635] The FEP obtained by the production method of the present disclosure has good moldability and is less likely to cause molding defects. In addition, it has good heat resistance, chemical resistance, solvent resistance, insulation properties, electrical properties, etc.

[0636] The method for producing the above FEP powder is a method of obtaining powder by drying the FEP obtained by the above-described production method of the present disclosure to form a powder.

[0637] The above powder may be fluorinated. The method for producing the above fluorinated powder is a method of obtaining a fluorinated powder by fluorinating the powder obtained by the above-described powder production method by supplying fluorine gas to the powder.

[0638] The method for producing the above FEP pellets is a method of obtaining pellets by pelletizing the FEP obtained by the above-described production method of the present disclosure.

[0639] The above pellets may be fluorinated. The method for producing the above fluorinated pellets is a method of obtaining fluorinated pellets by fluorinating the pellets obtained by the above-described pellet production method by supplying fluorine gas to the pellets.

[0640] Therefore, this FEP can be used, for example, in the production of coatings for electric wires, foamed electric wires, cables, wires, etc., and various molded articles such as tubes, films, sheets, filaments, etc.

[0641] (2) In the production method of the present disclosure, the polymerization of TFE / perfluoro(alkyl vinyl ether) copolymers such as PFA and MFA and TFE / perfluoroallyl ether copolymers is usually preferably carried out at a polymerization temperature of 10 to 100 °C and a polymerization pressure of 0.3 to 6.0 MPaG.

[0642] The preferred monomer composition (mol%) of the TFE / perfluoro(alkyl vinyl ether) copolymer is TFE:perfluoro(alkyl vinyl ether) = (90 to 99.7):(0.3 to 10), more preferably (97 to 99):(1 to 3). As the perfluoro(alkyl vinyl ether), those represented by the formula: CF 2 =CFORf 4 (wherein, Rf 4 is a perfluoroalkyl group having 1 to 6 carbon atoms) are preferably used.

[0643] In addition to TFE and perfluoro(alkyl vinyl ether), by polymerizing other monomers copolymerizable with these monomers, a copolymer of TFE, perfluoro(alkyl vinyl ether) and other monomers may be obtained as the TFE / perfluoro(alkyl vinyl ether) copolymer. Examples of other monomers include the above-mentioned fluorine-containing monomers (excluding TFE and perfluoro(alkyl vinyl ether)) and fluorine-free monomers. One or more kinds of other monomers can be used. The content of other monomer units in the TFE / perfluoro(alkyl vinyl ether) copolymer may be 0.1 to 2% by mass based on all monomer units.

[0644] The preferred monomer composition (mol %) of the TFE / perfluoroallyl ether copolymer is TFE:perfluoroallyl ether = (90 to 99.7):(0.3 to 10), more preferably (97 to 99):(1 to 3). As the perfluoroallyl ether, those represented by the formula: CF 2 =CFCF 2 ORf 4 (wherein, Rf 4 is a perfluoroalkyl group having 1 to 6 carbon atoms) are preferably used.

[0645] In addition to TFE and perfluoroallyl ether, by polymerizing other monomers copolymerizable with these monomers, a copolymer of TFE, perfluoroallyl ether and other monomers may be obtained as the TFE / perfluoroallyl ether copolymer. Examples of the other monomers include the above-mentioned fluorine-containing monomers (excluding TFE and perfluoroallyl ether) and fluorine-free monomers. One or more kinds of other monomers can be used. The content of the other monomer units in the TFE / perfluoroallyl ether copolymer may be 0.1 to 2% by mass based on all the monomer units.

[0646] In the polymerization of the above TFE / perfluoro(alkyl vinyl ether) copolymer and TFE / perfluoroallyl ether copolymer, the polymer (I) can be used within the range of use in the production method of the present disclosure, but usually, it is preferably added in an amount of 0.0001 to 10% by mass based on 100% by mass of the aqueous medium.

[0647] In the polymerization of the above TFE / perfluoro(alkyl vinyl ether) copolymer and TFE / perfluoroallyl ether copolymer, it is preferable to use cyclohexane, m...

Claims

1. A method for producing an aqueous fluoropolymer dispersion, comprising concentrating a composition containing a polymer (I) containing polymerization units (I) based on a monomer (I) represented by general formula (I), a fluoropolymer (excluding the polymer (I)), a nonionic surfactant, a non-fluorine-containing anionic surfactant, and an aqueous medium, to obtain an aqueous dispersion containing the fluoropolymer. CX １ X ３ =CX ２ R(-CZ １ Z ２ -A ０ ) ｍ (I) (In the formula, X １ and X ３ are each independently F, Cl, H or CF ３ and X ２ is H, F, an alkyl group or a fluorine-containing alkyl group; A ０ is an anionic group; R is a linking group; Z １ and Z ２ are each independently H, F, an alkyl group or a fluorine-containing alkyl group; and m is an integer of 1 or more.

2. The method according to claim 1, wherein the content of the fluorine-free anionic surfactant in the composition is 10 to 10,000 ppm by mass relative to the fluoropolymer.

3. 3. The method according to claim 1, wherein the surface tension of an aqueous solution containing 0.1% by mass of the non-fluorine-containing anionic surfactant measured at 25° C. is 60 mN / m or less.

4. The method according to any one of claims 1 to 3, wherein the content of the nonionic surfactant in the composition is 1.0 to 40 mass% relative to the fluoropolymer.

5. The method according to any one of claims 1 to 4, wherein the nonionic surfactant is at least one selected from the group consisting of nonionic surfactants represented by general formula (i) and nonionic surfactants represented by general formula (ii): R ６ -O-A １ -H (i) (In the formula, R ６ is a linear or branched primary or secondary alkyl group having 8 to 18 carbon atoms; A １ is a polyoxyalkylene chain. ( ７  ６ _ ４ ﯁ ２  ( ) ) (In the formula, R ７ is a linear or branched alkyl group having 4 to 12 carbon atoms; A ２ is a polyoxyethylene chain consisting of an average of 5 to 20 repeating oxyethylene groups.

6. The method according to any one of claims 1 to 5, wherein the composition has a pH of 4.0 to 11.

5.

7. The method according to any one of claims 1 to 6, wherein the fluoropolymer is polytetrafluoroethylene.

8. The method according to any one of claims 1 to 7, wherein the content of the fluoropolymer in the aqueous dispersion is 50 mass % or more with respect to the aqueous dispersion.

9. A fluoromonomer is polymerized in an aqueous medium in the presence of the polymer (I) to obtain a polymerization dispersion containing the fluoropolymer, the polymer (I) and an aqueous medium, and then The method according to any one of claims 1 to 8, wherein the composition is obtained by mixing the polymer dispersion, the nonionic surfactant, and the non-fluorine-containing anionic surfactant.

10. The process according to claim 9, wherein the fluoromonomer is polymerized substantially in the absence of a fluorine-containing surfactant.

11. The method according to claim 9 or 10, wherein the polymer dispersion and the composition are subjected to the concentration without being brought into contact with either an anion exchange resin or a cation exchange resin.

12. A polymer (I) containing a polymerization unit (I) based on a monomer (I) represented by general formula (I), Fluoropolymers (excluding polymer (I)), non-ionic surfactants, and aqueous medium An aqueous fluoropolymer dispersion comprising: The content of the polymer (I) is 500 ppm by mass or less relative to the aqueous fluoropolymer dispersion, The content of the fluoropolymer is 50% by mass or more and 70% by mass or less based on the fluoropolymer aqueous dispersion. Aqueous fluoropolymer dispersions. CX １ X ３ =CX ２ R(-CZ １ Z ２ -A ０ ) ｍ (I) (In the formula, X １ and X ３ are each independently F, Cl, H or CF ３ and X ２ is H, F, an alkyl group or a fluorine-containing alkyl group; A ０ is an anionic group; R is a linking group; Z １ and Z ２ are each independently H, F, an alkyl group or a fluorine-containing alkyl group; and m is an integer of 1 or more.

13. The aqueous fluoropolymer dispersion according to claim 12, which has a viscosity at 25°C of 5.0 mPa·s or more and 300 mPa·s or less.

14. The aqueous fluoropolymer dispersion according to claim 12 or 13, wherein the content of the nonionic surfactant is 4.0 mass % or more and 12 mass % or less based on the fluoropolymer.

15. The aqueous fluoropolymer dispersion according to any one of claims 12 to 14, which is substantially free of a fluorine-containing surfactant.

16. Fluoropolymers, non-ionic surfactants, and aqueous medium An aqueous fluoropolymer dispersion comprising: Substantially free of fluorine-containing surfactants, The viscosity at 25°C is 100 mPa·s or less, The color tone of the impregnated fiber obtained by impregnating a glass fiber with the aqueous fluoropolymer dispersion and baking it at 380° C. is L in the CIELAB color scale ＊ or a value of 74.0 or more on the CIELAB color scale ＊ is 1.0 or less, The content of the fluoropolymer is 50% by mass or more and 70% by mass or less based on the fluoropolymer aqueous dispersion, The content of the nonionic surfactant is 4.0% by mass or more and 12% by mass or less based on the fluoropolymer. Aqueous fluoropolymer dispersions.

17. 17. The aqueous fluoropolymer dispersion according to claim 15, wherein the fluorine-containing surfactant is an anionic fluorine-containing surfactant containing fluorine in the anionic moiety having a molecular weight of 800 or less.

18. The aqueous fluoropolymer dispersion according to any one of claims 15 to 17, wherein the content of the fluorine-containing surfactant is 100 ppb by mass or less.

19. The fluorine-containing surfactant is F(CF ２ ) ７ COOM、 F(CF ２ ) ５ COOM、 H(CF ２ ) ６ COOM、 H(CF ２ ) ７ COOM、 CF ３ O(CF ２ ) ３ OCHFCF ２ AOM、 C ３ F ７ OCF(CF ３ )CF ２ OCF(CF ３ )COOM、 CF ３ CF ２ CF ２ OCF(CF ３ )COOM、 CF ３ CF ２ OCF ２ CF ２ OCF ２ COOM、 C ２ F ５ OCF(CF ３ )CF ２ OCF(CF ３ )COOM、 CF ３ OCF(CF ３ )CF ２ OCF(CF ３ )COOM、 CF ２ ClCF ２ CF ２ OCF(CF ３ )CF ２ OCF ２ COOM、 CF ２ ClCF ２ CF ２ OCF ２ CF(CF ３ )OCF ２ COOM、 CF ２ ClCF(CF ３ )OCF(CF ３ )CF ２ OCF ２ COOM、 CF ２ ClCF (CF ３ ) O.C.F. ２ CF (CF ３ ) O.C.F. ２ COOM, and 【Chemistry 32】 (In each formula, M is H, metal atom, NR ７ ４ , optionally substituted imidazolium, optionally substituted pyridinium or optionally substituted phosphonium; R ７ The fluoropolymer aqueous dispersion according to any one of claims 15 to 18, wherein the compound is represented by the formula:

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