Method for producing particles containing fluorine-containing polymer

Abstract

Provided is a method for producing particles containing a fluorine-containing polymer, said method being capable of producing particles containing a fluorine-containing polymer having a low content of impurities. This method for producing particles containing a fluorine-containing polymer is a method for producing particles containing a fluorine-containing polymer having a group capable of being converted into an ion exchange group, said method comprising preparing a liquid composition containing a fluorine-containing polymer and a first solvent, then mixing the liquid composition with a second solvent, and aggregating the fluorine-containing polymer, thereby producing particles containing a fluorine-containing polymer having a group capable of being converted into an ion exchange group. The first solvent is an olefin having a fluorine atom and a chlorine atom, and the second solvent is an olefin having a fluorine atom and a chlorine atom.

Description

Technical Field

[0001] This invention relates to a method for manufacturing particles containing fluoropolymers. Background Technology

[0002] The ion exchange membrane (electrolyte membrane) of solid polymer fuel cells and water electrolysis devices is made by forming a membrane from a fluoropolymer containing ion exchange groups such as sulfonic acid groups.

[0003] Here, a fluoropolymer having ion-exchange groups such as sulfonic acid groups is manufactured by hydrolyzing and acidifying the fluorosulfonyl groups of a fluoropolymer having groups such as fluorosulfonyl groups that can be converted into ion-exchange groups.

[0004] As a method for manufacturing fluoropolymers having groups that can be converted into ion-exchange groups, Example 1 of Patent Document 1 discloses the following method: In the presence of an organic solvent (CF3CF2CF2CF2CF2CF2H), an organic solvent (HCF2CF2OCH2CF3) is added to a polymer solution obtained by copolymerizing tetrafluoroethylene and monomers represented as CF2=CFOCF2CF(CF3)OCF2CF2SO2F, causing the fluoropolymer to aggregate and obtain particles containing the fluoropolymer.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent No. 6642452 Summary of the Invention

[0008] The problem the invention aims to solve

[0009] Particles containing fluoropolymers with groups capable of being converted into ion-exchange groups sometimes contain impurities such as unreacted monomers. When particles containing fluoropolymers contain a large amount of impurities, the performance of ion-exchange membranes made from them may be reduced.

[0010] Referring to the method described in Example 1 of Patent Document 1, the inventors manufactured particles containing a fluoropolymer having groups that can be converted into ion-exchange groups, and found that there is room for improvement in the content of impurities in the particles.

[0011] The present invention was made in view of the above-mentioned problems, and the problem is to provide a method for manufacturing fluoropolymer particles that can produce particles containing fluoropolymers with low impurity content.

[0012] Solution for solving the problem

[0013] The inventors conducted in-depth research on the above-mentioned issues and found that: after preparing a liquid composition containing a fluoropolymer and a first solvent, mixing the liquid composition with a second solvent to cause the fluoropolymer to aggregate reduces the impurity content in the resulting fluoropolymer-containing particles. The second solvent is an olefin having fluorine and chlorine atoms. Thus, the present invention is completed.

[0014] That is, the inventors discovered that the above-mentioned problems can be solved by the following configuration. [1]

[0016] A method for manufacturing particles comprising a fluoropolymer, wherein the fluoropolymer has groups capable of being converted into ion-exchange groups, wherein in the manufacturing method,

[0017] After preparing a liquid composition comprising the above-mentioned fluoropolymer and the first solvent,

[0018] The above liquid composition is mixed with a second solvent to aggregate the above fluoropolymer to form particles containing the above fluoropolymer, wherein the second solvent is an olefin having fluorine and chlorine atoms. [2]

[0020] According to the manufacturing method of the fluoropolymer-containing particles described in [1], the olefin has 3 carbon atoms. [3]

[0022] According to the manufacturing method of the fluoropolymer-containing particles described in [1] or [2], the standard boiling point of the olefin is 14~89°C. [4]

[0024] The method for manufacturing particles containing a fluoropolymer according to any one of [1] to [3], wherein the fluoropolymer comprises a tetrafluoroethylene-based unit and a unit based on the compound shown in formula (1).

[0025] Equation (1) CF2=CF-L-(A) n

[0026] In formula (1), L is an optional perfluorocarbon group with an n+1 valence containing an ether oxygen atom, A is a group that can be converted into a sulfonic acid functional group, and n is 1 or 2. [5]

[0028] According to the method for manufacturing particles containing fluoropolymers as described in [4], the first solvent comprises at least one selected from the group consisting of a compound represented by formula (1) and an organic solvent. [6]

[0030] The method for manufacturing particles containing a fluoropolymer according to any one of [1] to [5], wherein the mass ratio of the content of the fluoropolymer in the liquid composition to the content of the first solvent is 0.050 to 0.43. [7]

[0032] The method for manufacturing particles containing a fluoropolymer according to any one of [1] to [6], wherein when the liquid composition is mixed with the second solvent, the mass ratio of the second solvent to the mass of the first solvent in the liquid composition is 1.0 to 8.0. [8]

[0034] The method for manufacturing particles containing a fluoropolymer according to any one of [1] to [7], wherein the content of the first solvent is 70% by mass or more and 95% by mass or less relative to the total mass of the liquid composition. [9]

[0036] The method for manufacturing particles containing fluoropolymers according to any one of [1] to [8], wherein the average particle size of the particles is 38 μm or more and 10,000 μm or less.

[10]

[0038] The method for manufacturing particles containing fluoropolymers according to any one of [1] to [9], wherein the above mixing is carried out using the above liquid composition having a temperature of 20°C or higher and 60°C or lower and the above second solvent having a temperature of -15°C or higher and 30°C or lower.

[0039] The effects of the invention

[0040] According to the present invention, a method for manufacturing fluoropolymer-containing particles capable of producing particles containing fluoropolymers with low impurity content can be provided. Detailed Implementation

[0041] Unless otherwise stated, the following definitions apply to this specification and the claims as a whole.

[0042] "Ion exchange group" refers to a group that can exchange at least a portion of the ions contained in the group for other ions, such as sulfonic acid functional groups and carboxylic acid functional groups.

[0043] "Sulfonic acid functional group" refers to a sulfonic acid group (-SO3H) or a sulfonate group. Here, examples of sulfonate groups include (-SO3H). - Ma + 、(-SO3 - 2Mb 2+ and (-SO3)- 3Mc 3+ (Among them, Ma) + Mb is an alkali metal ion or a quaternary ammonium cation. 2+ Mc is a divalent metal ion. 3+ (These are trivalent metal ions). It should be noted that when there are two ligands, the number of ion exchange groups is counted as 2, and when there are three ligands, the number of ion exchange groups is counted as 3.

[0044] "Carboxylic acid type functional group" refers to a carboxylic acid group (-COOH) or a carboxylate group. Here, examples of carboxylate groups include (-COO) - Ma + (-COO) - 2Mb 2+ and (-COO) - 3Mc 3+ (Among them, Ma) + Mb is an alkali metal ion or a quaternary ammonium cation. 2+ Mc is a divalent metal ion. 3+ (These are trivalent metal ions). It should be noted that when there are two ligands, the number of ion exchange groups is counted as 2, and when there are three ligands, the number of ion exchange groups is counted as 3.

[0045] "A group that can be converted into an ion exchange group" refers to a group that can be converted into an ion exchange group through treatments such as hydrolysis or acidification.

[0046] "A group that can be converted into a sulfonic acid functional group" refers to a group that can be converted into a sulfonic acid functional group through treatments such as hydrolysis or acidification.

[0047] "A group that can be converted into a carboxylic acid functional group" refers to a group that can be converted into a carboxylic acid functional group through known treatments such as hydrolysis or acidification.

[0048] In polymers, a "unit" refers to an atomic group derived from one molecule of a monomer, formed through monomer polymerization. A unit can be a atomic group formed directly through the polymerization reaction, or a portion of the atomic group can be transformed into a different structural group by processing the polymer obtained through the polymerization reaction. It should be noted that, as appropriate, units derived from each monomer will be referred to by the name of the monomer to which they are labeled "unit."

[0049] The numerical range indicated by "~" refers to the range of values ​​recorded before and after "~" as both lower and upper limits. Within the numerical ranges described in this specification, the upper or lower limit recorded in a particular numerical range can be replaced with the upper or lower limit of another numerical range described in other stages. Furthermore, within the numerical ranges described in this specification, the upper or lower limit recorded in a particular numerical range can also be replaced with the values ​​shown in the embodiments.

[0050] [Method for manufacturing particles containing fluoropolymers]

[0051] The method for manufacturing the fluoropolymer of the present invention is a method for manufacturing particles of a fluoropolymer (hereinafter also referred to as "polymer F") having groups that can be converted into ion exchange groups. In the manufacturing method, after preparing a liquid composition comprising the polymer F and a first solvent, the liquid composition is mixed with a second solvent to aggregate the polymer F and form particles comprising the polymer F. The second solvent is an olefin having fluorine atoms and chlorine atoms.

[0052] According to this manufacturing method, it is possible to produce particles containing fluoropolymers with low impurity content. The detailed reasons are not yet clear, but it is believed that by using a second solvent in the aggregation of polymer F, the incorporation of components other than polymer F (such as monomers used in the manufacture of polymer F, oligomers generated in the manufacture of polymer F, various solvents, etc.) into the particles is suppressed.

[0053] Furthermore, it is believed that by using a second solvent in the aggregation of polymer F, it becomes easier to remove components other than polymer F from the particles when the aggregated polymer F is subjected to cleaning, drying, or other treatments.

[0054] [Liquid Composition]

[0055] The liquid composition comprises polymer F and a first solvent. The liquid composition may be a solution obtained by dissolving polymer F in the first solvent, or a dispersion obtained by dispersing polymer F in the first solvent.

[0056] The turbidity of the liquid composition is preferably 500 NTU or less. Such a turbid liquid composition can be described as a solution obtained by dissolving polymer F in the first solvent, or a dispersion obtained by dispersing polymer F in the first solvent.

[0057] Here, the turbidity of the liquid composition can be measured using the liquid composition obtained in step 1 described later, employing a turbidimeter with a scattered light measurement method. Specifically, the turbidity is obtained by measuring 90° scattered light (measurement wavelength: 850 nm) at room temperature using a portable turbidimeter TN-100 manufactured by EUTECH INSTRUMENTS. The sample for measurement is prepared by placing 10 mL of the sample in a borosilicate glass vial (25 mm in diameter and 51 mm in height). Furthermore, calibration curves can be prepared using calibration solutions (0.02 NTU, 20.0 NTU, 100 NTU, 800 NTU) containing EPA-based polymer-based standard substances.

[0058] <Polymer F>

[0059] Polymer F is not particularly limited as long as it is a polymer having fluorine atoms and a group that can be converted into an ion exchange group. However, from the perspective of further improving the effects of the present invention, polymer F-1 or polymer F-2 shown below are preferred.

[0060] (Polymer F-1)

[0061] Polymer F-1 is a copolymer comprising units based on fluorinated olefins and units based on fluorinated monomers having groups that can be converted into ion-exchange groups, more preferably a copolymer comprising units based on fluorinated olefins (preferably tetrafluoroethylene) and units based on fluorinated monomers having groups that can be converted into sulfonic acid functional groups (preferably compounds represented by formula (1) described later).

[0062] Polymer F-1 preferably does not have a cyclic ether structure.

[0063] Examples of fluorinated olefins include fluoroolefins with 2 to 3 carbon atoms having one or more fluorine atoms in their molecule. Specific examples of fluoroolefins include tetrafluoroethylene (hereinafter also referred to as "TFE"), trifluorochloroethylene, vinylidene fluoride, vinyl fluoride, and hexafluoropropylene. Among these, TFE is preferred from the perspectives of monomer manufacturing cost, reactivity with other monomers, and the superior properties of the resulting polymer F-1.

[0064] Fluoroolefins can be used alone or in combination of two or more.

[0065] The content of fluoroolefin-based units relative to all units of polymer F-1 is preferably 11% by mass or more, more preferably 38% by mass or more, and preferably 59% by mass or less, more preferably 55% by mass or less.

[0066] Examples of fluorinated monomers that have groups capable of being converted into ion-exchange groups include compounds that have one or more fluorine atoms in their molecules, have olefinic double bonds, and have groups capable of being converted into sulfonic acid functional groups.

[0067] As a fluorinated monomer having a group that can be converted into an ion-exchange group, the compound shown in formula (1) is preferred from the aspects of monomer manufacturing cost, reactivity with other monomers, and the excellent properties of the resulting polymer F-1.

[0068] Equation (1) CF2=CF-L-(A) n

[0069] L is an optional perfluorocarbon group with an n+1 valence containing an ether-type oxygen atom.

[0070] The oxygen atom in an ether can be located at the end of a perfluorocarbon group or between carbon atoms.

[0071] The number of carbons in the n+1 valence perfluorocarbon group is preferably 1 or more, more preferably 2 or more, and preferably 20 or less, more preferably 10 or less.

[0072] As L, preferably a perfluoroaliphatic hydrocarbon group with an n+1 valence containing an ether oxygen atom is preferred, more preferably a perfluoroalkylene group with a divalent valence containing an ether oxygen atom as n=1, or a perfluoroaliphatic hydrocarbon group with a trivalent valence containing an ether oxygen atom as n=2.

[0073] The aforementioned divalent perfluoroalkylene groups can be either linear or branched.

[0074] A is a group capable of being converted into a sulfonic acid functional group. Preferably, the group capable of being converted into a sulfonic acid functional group is one that can be converted through hydrolysis. Specific examples of groups capable of being converted into sulfonic acid functional groups include -SO2F, -SO2Cl, and -SO2Br.

[0075] n is 1 or 2.

[0076] As the compound represented by formula (1), the compounds represented by formula (1-1), formula (1-2), formula (1-3), and formula (1-4) are preferred.

[0077] Equation (1-1) CF2=CF-OR f1 -A

[0078] Equation (1-2) CF2=CF-R f1 -A

[0079]

[0080]

[0081] R f1 The perfluoroalkylene group is a perfluoroalkylene group in which oxygen atoms are optionally present between carbon atoms. The number of carbon atoms in the perfluoroalkylene group is preferably 1 or more, more preferably 2 or more, and further preferably 20 or less, more preferably 10 or less.

[0082] R f2 It is a perfluoroalkylene group that is a single bond or optionally contains an oxygen atom between carbon atoms. The number of carbon atoms in the perfluoroalkylene group is preferably 1 or more, more preferably 2 or more, and preferably 20 or less, more preferably 10 or less.

[0083] R f3 It is a perfluoroalkylene group that is a single bond or optionally contains an oxygen atom between carbon atoms. The number of carbon atoms in the perfluoroalkylene group is preferably 1 or more, more preferably 2 or more, and preferably 20 or less, more preferably 10 or less.

[0084] r is 0 or 1.

[0085] m is 0 or 1.

[0086] The definition of A in the formula is as described above.

[0087] As for the compounds shown in formula (1-1) and formula (1-2), the compound shown in formula (1-5) is preferred.

[0088] Equation (1-5) CF2 = CF - (CF2) x -(OCF2CFY) y -O- (CF2) z -SO3F

[0089] x is 0 or 1, y is an integer from 0 to 2, z is an integer from 1 to 4, and Y is F or CF3.

[0090] As specific examples of the compounds shown in formula (1-1), the following compounds can be cited. In the formula, w is an integer from 1 to 8, and x is an integer from 1 to 5.

[0091] CF2 = CF - O - (CF2) w -SO2F

[0092] CF2=CF-O-CF2CF(CF3)-O-(CF2) w -SO2F

[0093] CF2 = CF - [O - CF2CF (CF3)] x -SO2F

[0094] As specific examples of the compounds shown in formula (1-2), the following compounds can be cited. In the formula, w is an integer from 1 to 8.

[0095] CF2 = CF - (CF2) w -SO2F

[0096] CF2 = CF - CF2 - O - (CF2) w -SO2F

[0097] As the compound shown in formula (1-3), the compound shown in formula (1-3-1) is preferred.

[0098]

[0099] R f4 It is a straight-chain perfluoroalkylene group with 1 to 6 carbon atoms, R f5 It is a straight-chain perfluoroalkylene group with 1 to 6 carbon atoms, consisting of a single bond or optionally containing an oxygen atom between carbon atoms. The definitions of r and A are as described above.

[0100] The following can be cited as specific examples of the compounds shown in formula (1-3-1).

[0101]

[0102] As the compound represented by formula (1-4), the compound represented by formula (1-4-1) is preferred.

[0103]

[0104] R in the formula f1 R f2 The definitions of A and A are as described above.

[0105] The following can be cited as specific examples of the compounds shown in formula (1-4-1).

[0106]

[0107] Fluorinated monomers with groups that can be converted into ion exchange groups can be used alone or in combination of two or more.

[0108] The content of units based on fluorinated monomers having groups that can be converted into ion exchange groups is preferably 41% by mass or more, more preferably 45% by mass or more, and preferably 89% by mass or less, more preferably 62% by mass or less, relative to all units of polymer F-1.

[0109] In the manufacture of polymer F-1, monomers other than those mentioned above (hereinafter also referred to as "other monomers") may also be used.

[0110] As a specific example of other monomers, CF2=CFR can be cited. f6 (where R) f6 (A perfluoroalkyl group with 2 to 10 carbon atoms), CF2=CF-OR f7 (where R) f7 (A perfluoroalkyl group with 1 to 10 carbon atoms), CF2=CFO (CF2) v CF = CF2 (where v is an integer from 1 to 3).

[0111] From the perspective of maintaining ion exchange performance, the content of units based on other monomers is preferably 30% by mass or less relative to the total number of units in polymer F-1.

[0112] (Polymer F-2)

[0113] Polymer F-2 is a fluoropolymer having units based on monomers having cyclic ether structures and having ion-exchange groups, preferably a copolymer having units based on monomers having cyclic ether structures and units based on fluoropolymers having groups that can be converted into ion-exchange groups.

[0114] Specific examples of monomers having a cyclic ether structure include monomers m11, m12, m21, and m22.

[0115] The monomer m11 is the monomer shown in formula (m11). As a suitable way to use monomer m11, formulas (m11-1) to (m11-4) can be given.

[0116]

[0117] R 11 The perfluoroalkyl group is optionally a divalent perfluoroalkyl group having an ether-bonded oxygen atom. When the perfluoroalkyl group has an ether-bonded oxygen atom, the number of oxygen atoms can be one or more. Furthermore, the oxygen atom can be located between carbon-carbon bonds or at the end of a carbon bond in the perfluoroalkyl group. The perfluoroalkyl group can be linear or branched, preferably linear.

[0118] R 12 R 13 R 15 and R 16 Each is independently a monovalent perfluoroalkyl or fluorine atom with an ether bond oxygen atom. From the perspective of high polymerization reactivity, R... 15 and R 16 Preferably, at least one of them is a fluorine atom, and more preferably both are fluorine atoms.

[0119] R 14 It can be a monovalent perfluoroalkyl group, fluorine atom, or -R with an ether bond oxygen atom. 11The group represented by SO2F. When the perfluoroalkyl group has an ether-bonded oxygen atom, the number of oxygen atoms can be one or more. Furthermore, the oxygen atom can be located between carbon-carbon bonds or at the end of a carbon bond in the perfluoroalkyl group. The perfluoroalkyl group can be linear or branched, preferably linear. In formula (m11), two R... 11 In the case of two Rs 11 They can be the same or different.

[0120] The monomer m12 is the monomer shown in formula (m12). As a suitable way to use monomer m12, formulas (m12-1) to (m12-2) can be given.

[0121]

[0122] R 21 It is a perfluoroalkylene group having 1 to 6 carbon atoms or a perfluoroalkylene group having 2 to 6 carbon atoms with ether-bonded oxygen atoms between carbon-carbon bonds. When the perfluoroalkylene group has ether-bonded oxygen atoms, the number of oxygen atoms can be one or more. The perfluoroalkylene group can be linear or branched, preferably linear.

[0123] R 22 It is a fluorine atom, a perfluoroalkyl group having 1 to 6 carbon atoms, a perfluoroalkyl group having 2 to 6 carbon atoms with ether-bonded oxygen atoms between carbon-carbon bonds, or -R. 21 The group represented by SO2F. When the perfluoroalkyl group has an ether-bonded oxygen atom, the number of oxygen atoms can be one or more. The perfluoroalkyl group can be linear or branched, preferably linear. In formula (m12), two R... 21 In the case of two Rs 21 They can be the same or different.

[0124] The monomer m21 is the monomer shown in formula (m21). As a suitable way of monomer m21, formulas (m21-1) to (m21-2) can be given.

[0125]

[0126] R 41 R 42 R 43 R 44 R 45 and R 46Each alkyl group is independently a monovalent perfluoroalkyl group or a fluorine atom, optionally possessing an ether-bonded oxygen atom. When the perfluoroalkyl group possesses an ether-bonded oxygen atom, the number of oxygen atoms can be one or more. Furthermore, the oxygen atom can be located between carbon-carbon bonds or at the end of a carbon bond in the perfluoroalkyl group. The perfluoroalkyl group can be linear or branched, preferably linear.

[0127] From the perspective of high polymerization reactivity, R 45 and R 46 Preferably, at least one of them is a fluorine atom, and more preferably both are fluorine atoms.

[0128] The monomer m22 is the monomer shown in formula (m22). As a suitable way to represent monomer m22, formulas (m22-1) to (m22-11) can be given.

[0129]

[0130] s can be 0 or 1, preferably 0.

[0131] R 51 and R 52 Each is independently a fluorine atom, a perfluoroalkyl group having 1 to 5 carbon atoms, or a spirocyclic ring formed by their connection (where s is 0).

[0132] R 53 and R 54 Each is independently a fluorine atom or a perfluoroalkyl group having 1 to 5 carbon atoms.

[0133] R 55 It is a fluorine atom, a perfluoroalkyl group having 1 to 5 carbon atoms, or a perfluoroalkoxy group having 1 to 5 carbon atoms. From the perspective of high polymerization reactivity, R... 55 The preferred atom is fluorine.

[0134] Perfluoroalkyl and perfluoroalkoxy compounds can be linear or branched, with linear being preferred.

[0135] The content of monomers with cyclic ether structures relative to all units of polymer F-2 is preferably 30% by mass or more, more preferably 48% by mass or more, and preferably 70% by mass or less, more preferably 63% by mass or less.

[0136] Specific examples of fluorinated monomers having groups that can be converted into ion exchange groups are the same as those of fluorinated monomers having groups that can be converted into ion exchange groups in polymer F-1.

[0137] The content of units based on fluorinated monomers having groups that can be converted into ion exchange groups is preferably 20% by mass or more, more preferably 28% by mass or more, and preferably 60% by mass or less, more preferably 50% by mass or less, relative to all units of polymer F-2.

[0138] Polymer F-2 can also have units based on fluorinated olefins. Specific examples of fluorinated olefins are the same as those in polymer F-1.

[0139] The content of fluoroolefin (especially TFE)-based units relative to all units of polymer F-2 is preferably 0% by mass or more, more preferably 1% by mass or more, and preferably 20% by mass or less, more preferably 10% by mass or less.

[0140] (Content of polymer F)

[0141] From the perspective of enabling polymer F to aggregate better, the content of polymer F relative to the total mass of the liquid composition is preferably 5% by mass or more, more preferably 14% by mass or more. Furthermore, from the perspective of better solubility or dispersibility in the first solvent, it is preferably 30% by mass or less, more preferably 20% by mass or less.

[0142] (Physical properties of polymer F)

[0143] The TQ value of polymer F is preferably 150°C or higher, more preferably 170°C or higher, even more preferably 200°C or higher, and preferably 350°C or lower, more preferably 340°C or lower, and even more preferably 300°C or lower.

[0144] The TQ value is a value related to the molecular weight of the polymer, expressed as a volumetric flow rate of 100 mm⁻¹. 3 Temperature per second is expressed as follows and is calculated using the following method.

[0145] The TQ value of polymer F was determined by the method described in the Examples section below.

[0146] When the groups of polymer F that can be converted into ion exchange groups are converted into ion exchange groups through known treatments such as hydrolysis and acidification, a fluoropolymer with ion exchange groups (hereinafter also referred to as "polymer H") can be obtained.

[0147] The ion exchange capacity of polymer H is preferably 0.8 mEq / g dry resin or more, more preferably 0.9 mEq / g dry resin or more, even more preferably 1.0 mEq / g dry resin or more, and preferably 2.5 mEq / g dry resin or less, more preferably 2.2 mEq / g dry resin or less, and even more preferably 2.0 mEq / g dry resin or less.

[0148] The ion exchange capacity of polymer H was determined by the method described in the Examples section below.

[0149] (Method for manufacturing polymer F)

[0150] As an example of a method for manufacturing polymer F, one can cite a method of copolymerizing the aforementioned monomers in the presence of a polymerization initiator within a reactor.

[0151] Specific examples of copolymerization methods include bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization.

[0152] In the case of solution polymerization, specific examples of polymerization solvents include chlorofluorocarbons, hydrochlorofluorocarbons, hydrofluorocarbons, and hydrofluoroethers.

[0153] Here, when polymer F is produced by solution polymerization, the polymerization solvent can be the first solvent contained in the liquid composition (described later).

[0154] Specific examples of polymerization initiators include acyl peroxides (disuccinic acid peroxide, benzoyl peroxide, perfluoro-benzoyl peroxide, lauroyl peroxide, bis(pentafluoropropionyl) peroxide, etc.), azo compounds (2,2'-azobis(2-amidinylpropane) hydrochloride, 4,4'-azobis(4-cyanopentanoic acid), dimethyl 2,2'-azodiisobutyrate, azodiisobutyronitrile, etc.), peroxide esters (tert-butyl peroxide isobutyrate, tert-butyl peroxypentanoate, etc.), peroxide dicarbonates (diisopropyl peroxide dicarbonate, bis(2-ethylhexyl) peroxide dicarbonate, etc.), hydrogen peroxides (diisopropylbenzene hydrogen peroxide, tert-butyl hydrogen peroxide, etc.), and dialkyl peroxides (di-tert-butyl peroxide, perfluoro-di-tert-butyl peroxide), etc.

[0155] Polymerization initiators can also be used in the form of a solution dissolved in a solvent (hereinafter also referred to as "initiator solution").

[0156] The solvent contained in the initiator solution may also be the first solvent contained in the liquid composition (described later).

[0157] The amount of polymerization initiator added relative to 100 parts by mass of monomer is preferably 0.0001 parts by mass or more, more preferably 0.001 parts by mass or more, and preferably 3 parts by mass or less, more preferably 2 parts by mass or less.

[0158] Monomers and polymerization initiators can be added to the reactor continuously or sequentially.

[0159] The amount of monomer added can be appropriately determined by ensuring that the content of each monomer unit in polymer F falls within the above-mentioned range.

[0160] The copolymerization temperature is preferably above 20°C, more preferably above 30°C, and preferably below 150°C, more preferably below 130°C.

[0161] The polymerization pressure (gauge pressure) is preferably 0.05 MPa or more, more preferably 0.5 MPa or more, and preferably 2 MPa or less, more preferably 1.5 MPa or less.

[0162] <First Solvent>

[0163] The first solvent is the solvent (good solvent) that dissolves or disperses polymer F.

[0164] Specific examples of the first solvent include organic solvents, unreacted monomers used in the manufacture of polymer F, and oligomers generated during the manufacture of polymer F.

[0165] The first solvent can be used alone or in combination with two or more. Among them, organic solvents and unreacted monomers used in the manufacture of polymer F are preferred, considering factors such as ease of acquisition, cost, boiling point, and separation and recovery.

[0166] From the perspective of the excellent solubility or dispersibility of polymer F, fluorinated solvents and hydrocarbon solvents are preferred organic solvents.

[0167] For fluorinated solvents, if the number of carbon atoms is too low, the boiling point is low, and the recyclability and operability at room temperature of the solvent are insufficient. If the number of carbon atoms is too high, the boiling point is high, and the recyclability of the solvent and the drying of the polymer after aggregation and separation become difficult. From this point of view, 1 to 8 is preferred, 2 to 7 is more preferred, and 3 to 6 is even more preferred.

[0168] For the standard boiling point of fluorinated solvents, if it is too low, the recyclability of the solvent and its operability at room temperature will be insufficient; if it is too high, the recyclability of the solvent and the drying of the polymer after aggregation and separation will become difficult. From this point of view, 20~200℃ is preferred, 34~140℃ is more preferred, and 48~83℃ is even more preferred.

[0169] Specific examples of fluorinated solvents include: CF3(CF2)4CF2H, CF3(CF2)6CF2H, HCF2(CF2)2CF2H, CF3CF2CHFCHFCF3, CF3CF(CF3)CHFCHFCF3, CF3CH2CF2CH3, and hydrofluorocarbons such as 1,1,2,2,3,3,4-heptafluorocyclopentane;

[0170] ClCF2CF2CHFCl (1,3-dichloro-1,1,2,2,3-pentafluoropropane), CF3CF2CHCl2, CH3CCl2F and other hydrochlorofluorocarbons;

[0171] HCF2CF2OCH2CF3, n-C3F7OCH3, n-C3F7OCHFCF3, n-C3F7OCH2CF3, n-C4F9OCH3, iso-C4F9OCH3 , n-C4F9OCH2CH3, n-C4F9OCH2CF3, CF3OCF (CF3) CF2OCH3, n-C3F7OCF (CF3) CF2OCHFCF3 and other hydrofluoroethers;

[0172] Chlorofluorocarbons such as CCl3F, CCl2F2, CClF2CClF2, Cl2FCCClF2;

[0173] (CF3)2CFC(O)CF(CF3)2, CF3CF2CF2C(O)CF(CF3)2, and other perfluoroketones;

[0174] Hydrochlorofluoroolefins such as CF3CCl=CH2, Z-form of CF3CF=CHCl, E-form of CF3CH=CHCl, Z-form of CF3CH=CHCl, E-form of CF3CCl=CHCl, E-form of CHF2CF=CHCl, Z-form of CHF2CF=CHCl, and Z-form of CHF2CF2CF2CF=CHCl;

[0175] Chlorofluoroolefins such as CF3CF=CCl2 and CF3CCl=CCl2;

[0176] Specific examples of hydrocarbon-based organic solvents include pentane, hexane, heptane, octane, hexadecane, isohexane, isooctane, isononane, isododecane, cycloheptane, cyclohexane, dicyclohexane, benzene, toluene, ethylbenzene, o-xylene, m-xylene, p-xylene, o-diethylbenzene, m-diethylbenzene, p-diethylbenzene, n-butylbenzene, sec-butylbenzene, tert-butylbenzene, methanol, ethanol, and tert-butanol.

[0177] As a specific example of an unreacted monomer used in the manufacture of polymer F, the compound shown in formula (1) above can be cited.

[0178] As a specific example of the oligomers generated when manufacturing polymer F, an example can be the oligomers generated by polymerizing the above-mentioned fluorinated olefins with the compound shown in formula (1) above, whose molecular weight is usually less than tens of thousands.

[0179] From the perspective of the excellent dispersibility and solubility of the liquid composition, and the ability to better aggregate polymer F in step 2 described later, the swelling degree of the first solvent to the suitable polymer F is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 7% by mass or more.

[0180] The swelling degree of polymer F based on the first solvent is determined by the following steps.

[0181] Polymer F particles were hot-pressed to obtain a 100 μm thick film. A 20 mm × 20 mm sample was cut from this film, and its dry mass (W1) was measured. The sample was then immersed in 50 g of the first solvent at 25 °C in a sealed environment for 16 hours. After removing the sample from the solvent and quickly wiping off the solvent, the swelling mass (W2) was measured. Based on the measured dry mass (W1) and swelling mass (W2), the degree of swelling was calculated using the following formula.

[0182] Swelling degree (%) = (W2-W1) / W1×100

[0183] From the perspective of improving the dispersibility or solubility of polymer F, the first solvent preferably contains at least one selected from unreacted monomers (preferably compounds represented by formula (1)) used to manufacture polymer F and organic solvents (preferably fluorinated solvents).

[0184] From the perspective of improving the solubility or dispersibility of polymer F, the content of the first solvent relative to the total mass of the liquid composition is preferably 70% by mass or more, more preferably 75% by mass or more, and even more preferably 80% by mass or more. In addition, from the perspective of suppressing excessive fine particle formation of the polymer in step 2, improving the filtration properties in step 3, and saving the amount of solvent used during aggregation, it is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less.

[0185] From the perspective of suppressing excessive micronization of the polymer in step 2, improving filterability in step 3, and saving the amount of solvent used during aggregation, the mass ratio of polymer F content to first solvent content (polymer F content / first solvent content) is preferably 0.050 or more, more preferably 0.054 or more, and even more preferably 0.060 or more. From the perspective of improving the solubility or dispersibility of polymer F, it is preferably 0.43 or less, more preferably 0.24 or less, and even more preferably 0.10 or less.

[0186] [Second Solvent]

[0187] The second solvent is an olefin having fluorine and chlorine atoms, which is a solvent (undesirable solvent) used to aggregate polymer F in a liquid medium to form polymer F particles.

[0188] As a specific example of the second solvent, the following can be cited:

[0189] Hydrochlorofluorocarbons (HCFCs) include CF3CCl=CH2 (14℃), Z-form of CF3CF=CHCl (15℃), E-form of CF3CH=CHCl (18℃), Z-form of CF3CH=CHCl (39℃), CF3CCl=CHCl (54℃), E-form of CHF2CF=CHCl (47~48℃), Z-form of CHF2CF=CHCl (54℃), and Z-form of CHF2CF2CF2CF=CHCl (89℃).

[0190] Chlorofluorocarbons such as CF3CF=CCl2 (46℃) and CF3CCl=CCl2 (88℃); etc.

[0191] It should be noted that the values ​​in parentheses in the above specific examples represent standard boiling points (boiling points at one atmosphere). Additionally, the boiling point of a mixture of the E and Z phases of CHF2CF=CHCl (with an E phase content of less than 10% by mass) is 54°C.

[0192] The second solvent can be used alone or in combination with two or more solvents.

[0193] From the perspective of further improving the effects of the present invention and improving the aggregation of polymer F, the olefin used as the second solvent preferably has 2 to 8 carbons, more preferably 2 to 5, and even more preferably 3.

[0194] From the perspective of ensuring sufficient operability at room temperature, the standard boiling point of the olefin as the second solvent is preferably 14°C or higher, more preferably 15°C or higher, and even more preferably 39°C or higher. In addition, from the perspective of facilitating the separation of polymer F from the polymerization medium, it is preferably 89°C or lower, more preferably 88°C or lower, and even more preferably 54°C or lower.

[0195] [Process]

[0196] In this specification, the process of preparing the liquid composition comprising polymer F and the first solvent is also referred to as "process 1".

[0197] Additionally, the following process is also referred to as "process 2": mixing the liquid composition with a second solvent to aggregate the polymer F and form particles containing polymer F.

[0198] The following is a detailed explanation of each process.

[0199] <Process 1>

[0200] There are no particular limitations on the preparation method of the liquid composition; for example, the following methods can be cited.

[0201] As an example of a method for preparing a liquid composition, a method can be described as follows: A dispersion or solution in which polymer F is dispersed or dissolved in unreacted monomers or organic solvents used in the manufacture of polymer F is obtained by bulk polymerization, and the resulting dispersion or solution is used as a liquid composition. In this case, the unreacted monomers and organic solvents are equivalent to the first solvent.

[0202] In the dispersion or solution obtained by bulk polymerization, in addition to polymer F and unreacted monomers, the aforementioned oligomers and other components equivalent to the first solvent may also be included.

[0203] Another example of a method for preparing a liquid composition is a method in which a dispersion or solution of polymer F is obtained by solution polymerization, and the resulting dispersion or solution is used as a liquid composition. In this case, the polymerization solvent is equivalent to the first solvent.

[0204] In the dispersion or solution obtained by solution polymerization, in addition to polymer F and polymerization solvent, it may also contain the above-mentioned unreacted monomers, oligomers and other components equivalent to the first solvent.

[0205] <Process 2>

[0206] In step 2, the liquid composition obtained in step 1 is mixed with the second solvent mentioned above to cause polymer F to aggregate.

[0207] Regarding the temperature of the liquid composition before mixing with the second solvent, from the perspective of excellent dispersibility and solubility of the liquid composition, suppression of polymer agglomeration in step 2, and ability to produce particles containing polymer F with an appropriate particle size, it is preferably 20°C or higher, more preferably 23°C or higher, and even more preferably 25°C or higher. In addition, from the perspective of saving energy for heating the liquid composition in step 1, it is preferably 70°C or lower, more preferably 60°C or lower, and even more preferably 50°C or lower.

[0208] Regarding the temperature of the second solvent before it is mixed with the liquid composition, from the perspective of saving energy used for cooling the second solvent in step 2, it is preferably -15°C or higher, more preferably -10°C or higher, and even more preferably -5°C or higher. In addition, from the perspective of the polymer F being easy to aggregate and suppressing excessive micronization of the polymer in step 2, it is preferably 30°C or lower, more preferably 28°C or lower, and even more preferably 25°C or lower.

[0209] When mixing the liquid composition with the second solvent, it is preferable to perform a stirring process.

[0210] The stirring conditions can be those that are already known. For example, the optimal stirring speed varies depending on the shape of the stirring blades and the size of the processing tank, but is preferably 1 to 500 rpm.

[0211] The stirring process can be carried out under normal pressure or under pressure in a pressure vessel.

[0212] The stirring time is preferably 15 minutes to 16 hours, more preferably 30 minutes to 8 hours. If the temperature of the second solvent is high, the stirring time will be shorter.

[0213] There are no particular restrictions on the stirring method; any known stirring device can be used.

[0214] When the liquid composition is mixed with the second solvent in step 2, from the perspective of enabling the polymer F to aggregate better, the mass ratio of the second solvent to the mass of the first solvent in the liquid composition (mass of the second solvent / mass of the first solvent in the liquid composition) is preferably 1.0 or more, more preferably 1.5 or more, and even more preferably 2.0 or more.

[0215] From the viewpoint of easily making the particle size of polymer F particles within an appropriate range, the above-mentioned mass ratio (mass of the second solvent / mass of the first solvent in the liquid composition) is preferably 8.0 or less, more preferably 6.0 or less, and even more preferably 3.5 or less.

[0216] When mixing the liquid composition with the second solvent in step 2, the second solvent can be added to the liquid composition all at once, or it can be added in multiple batches.

[0217] When the second solvent is added in multiple stages, the first addition of the second solvent can be used to dilute the liquid composition.

[0218] When the second solvent is added in multiple batches, the type of the second solvent can be the same or different in each batch.

[0219] <Other processes>

[0220] The method for manufacturing fluoropolymers of the present invention may include steps other than those described above (hereinafter also referred to as "other steps").

[0221] As a specific example of other processes, process 3 can be given as follows: after process 2, the particles containing polymer F are separated and recovered from the liquid containing the particles containing polymer F.

[0222] As a separation method in step 3, known filtration methods such as pressure filtration, pressure filtration, atmospheric pressure filtration, and centrifugal filtration can be cited.

[0223] Step 3 may include a cleaning process in which the recovered particles containing polymer F are cleaned using a cleaning solvent (preferably the second solvent mentioned above).

[0224] The cleaning process can be performed once or multiple times.

[0225] Step 3 may include a drying process to dry the recovered particles containing polymer F. If a washing process is performed in step 3, the drying process is preferably performed after the washing process.

[0226] As drying methods, well-known drying methods such as hot air drying, vacuum drying, suction drying, infrared drying, and air (nitrogen) blowing drying can be cited.

[0227] The drying temperature during the drying process is preferably -15°C or higher, more preferably -10°C or higher, and preferably 80°C or lower, more preferably 70°C or lower.

[0228] The drying time in the drying process is preferably 30 minutes or more, more preferably 60 minutes or more, and preferably 24 hours or less, more preferably 21 hours or less.

[0229] [Particles containing polymer F]

[0230] In the particles containing polymer F obtained by this manufacturing method, the content of polymer F relative to the total mass of the particles containing polymer F is preferably 5% by mass or more, more preferably 15% by mass, even more preferably 24% by mass or more, and preferably 52% by mass or less, more preferably 46% by mass or less, and even more preferably 40% by mass or less.

[0231] For the average particle size of the polymer F-containing particles obtained by this manufacturing method, from the perspective of suppressing excessive micronization of polymer particles in step 2 and improving filterability in step 3, it is preferably 38 μm or more, more preferably 500 μm or more, and even more preferably 1000 μm or more. In addition, from the perspective of making it easier to remove components other than polymer F from the particles, it is preferably 10000 μm or less, more preferably 5000 μm or less, and even more preferably 2000 μm or less.

[0232] The average particle size of the particles containing polymer F was calculated from the measured particle size distribution by mechanical sieving using a test stainless steel sieve (JIS-Z8801).

[0233] Example

[0234] The present invention will be described in detail below with examples. Examples 1 to 4 are embodiments, and Examples 5 and 6 are comparative examples. However, the present invention is not limited to these examples.

[0235] [Determination of weight loss rate]

[0236] Weigh the particles containing polymer F obtained after the washing process in each example and determine the mass W1.

[0237] Next, the particles containing polymer F obtained after the washing process in each example were air-dried at 50°C for 2 hours in an oven (ESPEC CORP., small high-temperature chamber STH-120) with forced hot air circulation / ventilation. Starting from the air-drying under heating, the mass W2 (0.5) of the particles containing polymer F after 0.5 hours, the mass W2 (1) of the particles containing polymer F after 1 hour, and the mass W2 (2) of the particles containing polymer F after 2 hours were weighed respectively.

[0238] Based on the measured masses W1 and W2, the weight loss rate of the particles containing polymer F during each air-drying time under heating is calculated using the following formula (W).

[0239] The results are expressed using the exponent when the weight loss rate of formula (W) calculated based on the mass of W2 (0.5) in Example 5 is set to "100". It can be said that the smaller the value of the exponent, the fewer impurities are present in the particles containing polymer F. The results are shown in Table 2, which is described later.

[0240] Formula (W) Weight loss rate (%) = 100 × (W1 - W2) / W1

[0241] In the formula, W2 refers to W2(0.5), W2(1), or W2(2).

[0242] [Ion exchange capacity]

[0243] The air-dried particles containing polymer F in each example were vacuum-dried at 240°C for 16 hours. After weighing the dried polymer F in a polycarbonate container, the dried polymer F was immersed in a 0.7N NaOH solution (solvent: H₂O / CH₃OH = 10 / 90 (mass ratio)) at 60°C for at least 72 hours, thereby completely converting the -SO₂F groups of the dried polymer F to the Na salt form. The amount of NaOH in the NaOH solution impregnated with the dried polymer F was determined by reverse titration with 0.1 mol / L HCl using phenolphthalein as an indicator, and the ion exchange capacity (mIQ / g dried resin) was calculated from this. The results are shown in Table 2 below.

[0244] It should be noted that "meq / g" in the table refers to "milliequivalents / g of dry resin" as the unit of ion exchange capacity.

[0245] When there are three or more monomers, use 19The composition was determined by F-NMR, and the ion exchange capacity was calculated.

[0246] [TQ value]

[0247] In each example, the air-dried polymer-containing particles were vacuum-dried at 240°C for 16 hours. Using a rheometer (Shimadzu Corporation, CFT-500D) equipped with a nozzle of 1 mm length and 1 mm inner diameter, the vacuum-dried polymer-containing particles were melt-extruded while varying the temperature under an extrusion pressure of 2.94 MPa (gauge pressure). The polymer extrusion amount was calculated to be 100 mm. 3 The temperature per second is the TQ value. The results are shown in Table 2, which will be described later.

[0248] [monomer]

[0249] TFE: Tetrafluoroethylene

[0250] • Monomer m1: CF2=CFOCF2CF(CF3)O(CF2)2SO2F

[0251] • Monomer m2

[0252]

[0253] • Monomer m3: Perfluoro(2,2-dimethyl)-1,3-dioxacyclopentene

[0254] [Free radical polymerization initiator]

[0255] V-601: Dimethyl 2,2'-azobis(2-methylpropionic acid) ester

[0256] AIBN: 2,2'-Azobisisobutyronitrile

[0257] ·PFB: CF3CF2CF2C (=O) OOC (=O) CF2CF2CF3

[0258] [solvent]

[0259] ·HCFO-1233yd(E) / (Z): A mixture of the E and Z phases of CHF2CF=CHCl (AMOLEA (registered trademark) AS-300 (manufactured by AGC Corporation), standard boiling point 54℃)

[0260] • HFE-347pc-f: HCF2CF2OCH2CF3, Asahiklin AE-3000 (manufactured by AGC Corporation), standard boiling point 56℃

[0261] • HFC-52-13p: CF3(CF2)4CF2H, Asahiklin AC-2000 (manufactured by AGC Corporation), standard boiling point 71.8℃

[0262] [Example 1]

[0263] <Process 1>

[0264] 186 g of monomer m1 was added to a 230 mL stainless steel reactor and cryogenically degassed using liquid nitrogen. The reactor was then stirred at 300 rpm, heated to 55 °C, and 0.17 MPa of nitrogen gas was introduced. TFE was then introduced to bring the total pressure to 0.85 MPaG (gauge pressure, the same applies below).

[0265] A 3.82 g initiator solution, obtained by dissolving V-601 (as a free radical polymerization initiator) at a concentration of 1.43% by mass in monomer m1, was injected into the reactor to initiate polymerization. TFE was continuously added while maintaining the initial pressure.

[0266] When the amount of TFE continuously introduced reaches 15.4g, the reactor is cooled to 10°C, and the unreacted TFE is discharged to obtain a solution of polymer F1 dissolved in unreacted monomer m1, i.e., liquid composition 1.

[0267] <Process 2>

[0268] 100g of liquid composition 1 was diluted with 61.0g of HCFO-1233yd(E) / (Z). The diluted liquid composition was kept at 50°C and added to 193g of HCFO-1233yd(E) / (Z) at 25°C and stirred to allow polymer F1 to aggregate and form particles containing polymer F1.

[0269] After stirring, the liquid containing particles containing polymer F1 was filtered using filter paper. 202 g of HCFO-1233yd(E) / (Z) at 25°C was added to the separated and recovered particles containing polymer F1, and the mixture was stirred and then filtered for washing. The washing process was repeated a total of 3 times, yielding 42.6 g of particles containing polymer F1.

[0270] The recovered particles containing polymer F1 were dried at 50°C in a hot air circulating oven for 2 hours to obtain 25.5g of particles containing polymer F1.

[0271] Using air-dried particles containing polymer F1, the ion exchange capacity and TQ value were determined according to the method described above.

[0272] [Example 2]

[0273] <Process 1>

[0274] 162 g of monomer m1 was added to a 230 mL stainless steel reactor and thoroughly degassed using liquid nitrogen. The reactor was then stirred at 300 rpm and heated to 60 °C. TFE was added at this temperature until the pressure reached 1.30 MPaG.

[0275] A solution of 0.86 g of AIBN (4.74% by mass) dissolved in HCFO-1233yd(E) / (Z) was injected into the reactor to initiate polymerization. TFE was continuously added while maintaining the initial pressure.

[0276] When the amount of TFE continuously introduced reaches 8.1g, the reactor is cooled to 10℃, the unreacted TFE is discharged, and a solution of polymer F2 dissolved in unreacted monomer m1 and HCFO-1233yd(E) / (Z) is obtained, namely liquid composition 2.

[0277] <Process 2>

[0278] 167g of liquid composition 2 was kept at 25°C and added to 451g of HCFO-1233yd(E) / (Z) at 25°C and stirred to allow polymer F2 to aggregate and form particles containing polymer F2.

[0279] After stirring, the liquid containing particles containing polymer F2 was filtered through filter paper. 150g of HCFO-1233yd(E) / (Z) at 25°C was added to the separated and recovered particles containing polymer F2, and the mixture was stirred and then filtered for washing. The washing process was repeated a total of 3 times, yielding 26.6g of particles containing polymer F2.

[0280] The recovered particles containing polymer F2 were dried at 50°C in a hot air circulating oven for 2 hours to obtain 17.4g of particles containing polymer F2.

[0281] Using air-dried particles containing polymer F2, the ion exchange capacity and TQ value were determined according to the method described above.

[0282] [Example 3]

[0283] <Process 1>

[0284] 162 g of monomer mL was added to a 230 mL stainless steel reactor and cryogenically degassed using liquid nitrogen. The reactor was then stirred at 300 rpm and heated to 50 °C. TFE was added at this temperature until the pressure reached 1.25 MPaG.

[0285] A 1.25 g initiator solution, obtained by dissolving V-601 (as a free radical polymerization initiator) at a concentration of 3.34% by mass in HCFO-1233yd(E) / (Z), was injected into the reactor to initiate polymerization. TFE was continuously added while maintaining the initial pressure.

[0286] When the amount of TFE continuously introduced reaches 7.1g, the reactor is cooled to 10°C, the unreacted TFE is discharged, and a solution of polymer F3 dissolved in unreacted monomer m1 and HCFO-1233yd(E) / (Z) is obtained, namely liquid composition 3.

[0287] <Process 2>

[0288] 163g of liquid composition 3 was kept at 25°C and added to 525g of HCFO-1233yd(E) / (Z) at 25°C and stirred to allow polymer F3 to aggregate and form particles containing polymer F3.

[0289] After stirring, the liquid containing particles containing polymer F3 was filtered through filter paper. 150g of HCFO-1233yd(E) / (Z) at 25°C was added to the separated and recovered particles containing polymer F3, and the mixture was stirred and then filtered for washing. The washing process was repeated a total of 3 times, yielding 18.8g of particles containing polymer F3.

[0290] The recovered particles containing polymer F3 were dried at 50°C in a hot air circulating oven for 2 hours to obtain 13.8g of particles containing polymer F3.

[0291] Using air-dried particles containing polymer F3, the ion exchange capacity and TQ value were determined according to the method described above.

[0292] [Example 4]

[0293] <Process 1>

[0294] 108 g of monomer m2, 29.0 g of monomer m3 and 1.22 g of AC-2000 were added to a 230 mL stainless steel reactor. 1.05 g of AC-2000 solution was added, with the concentration of PFB as a free radical polymerization initiator being 3.0% by mass. After addition, liquid nitrogen was used to fully degas the solution.

[0295] Next, 4.15 g of TFE was added, stirred at 100 rpm, and heated to 24 °C to initiate polymerization. The internal temperature was maintained at 24 °C, and the reaction continued for 8 hours. Afterward, the mixture was cooled, and the unreacted TFE was vented. Then, the remaining monomer m3 was distilled off under reduced pressure at 24 °C for 3 hours to obtain a solution of polymer F4 dissolved in unreacted monomer m2 and AC-2000, i.e., liquid composition 4.

[0296] <Process 2>

[0297] 53.5 g of liquid composition 4 was diluted with 93.6 g of HCFO-1233yd(E) / (Z). The diluted liquid composition was kept at 25°C and added to 208 g of HCFO-1233yd(E) / (Z) at -6.3°C and stirred to allow polymer F4 to aggregate and form particles containing polymer F4.

[0298] After stirring, the liquid containing particles containing polymer F4 was filtered through filter paper. 165g of HCFO-1233yd(E) / (Z) at 25°C was added to the separated and recovered particles containing polymer F4, and the mixture was stirred and then filtered for washing. The washing process was repeated a total of 3 times, yielding 26.3g of particles containing polymer F4.

[0299] The recovered particles containing polymer F4 were dried at 50°C in a hot air circulating oven for 2 hours to obtain 13.3g of particles containing polymer F4.

[0300] Using air-dried particles containing polymer F4, the ion exchange capacity and TQ value were determined according to the method described above.

[0301] [Example 5]

[0302] <Process 1>

[0303] 189 g of monomer m1 was added to a 230 mL stainless steel reactor and cryogenically degassed using liquid nitrogen. The reactor was then stirred at 300 rpm, heated to 55 °C, and nitrogen gas at 0.17 MPa was introduced. TFE was then introduced to bring the total pressure to 0.85 MPaG.

[0304] A 3.82 g initiator solution, prepared by dissolving V-601 (1.43% by mass) in HFC-52-13p as a free radical polymerization initiator, was injected into the reactor to initiate polymerization. TFE was continuously added while maintaining the initial pressure.

[0305] When the amount of TFE continuously introduced reaches 15.4g, the reactor is cooled to 10°C, and the unreacted TFE is discharged to obtain a solution of polymer F5 dissolved in unreacted monomer m1 and HFC-52-13p, i.e., liquid composition 5.

[0306] <Process 2>

[0307] 100g of liquid composition 5 was diluted with 60.4g of HFC-52-13p. The diluted liquid composition was kept at 25°C and added to 466g of HFE-347pc-f at -30°C and stirred to allow polymer F5 to aggregate and form particles containing polymer F5.

[0308] After stirring, the liquid containing particles containing polymer F5 was filtered through filter paper. 201 g of HFE-347pc-f at 25°C was added to the separated and recovered polymer particles, stirred, and then filtered for washing. This washing process was repeated a total of 3 times, yielding 63.9 g of particles containing polymer F5.

[0309] The recovered particles containing polymer F5 were dried at 50°C in a hot air circulating oven for 2 hours to obtain 26.1g of particles containing polymer F5.

[0310] Using air-dried particles containing polymer F5, the ion exchange capacity and TQ were determined according to the method described above.

[0311] [Example 6]

[0312] <Process 1>

[0313] 189 g of monomer m1 was added to a 230 mL stainless steel reactor and cryogenically degassed using liquid nitrogen. The reactor was then stirred at 300 rpm, heated to 55 °C, and 0.14 MPa of nitrogen gas was introduced, followed by TFE to bring the total pressure to 0.82 MPaG.

[0314] A solution of 3.87 g of V-601 (1.41% by mass) dissolved in HFE-347pc-f, used as a free radical polymerization initiator, was injected into the reactor to initiate polymerization. TFE was continuously added while maintaining the initial pressure. When 15.4 g of TFE had been continuously added, the reactor was cooled to 10°C, and the unreacted TFE was vented, yielding a liquid composition 6 consisting of polymer F6 dissolved in unreacted monomer m1 and HFE-347pc-f.

[0315] <Process 2>

[0316] 101g of liquid composition 6 was diluted with 62.5g of HFE-347pc-f. The diluted liquid composition was kept at 50°C and added to 194g of HFE-347pc-f at 25°C and stirred to aggregate polymer F6 and form particles containing polymer F6.

[0317] After stirring, the liquid containing particles containing polymer F6 was filtered through filter paper. 199 g of HFE-347pc-f at 25°C was added to the separated and recovered polymer particles, stirred, and then filtered for washing. This washing process was repeated a total of 3 times, yielding 56.0 g of particles containing polymer F6.

[0318] The recovered particles containing polymer F6 were dried at 50°C in a hot air circulating oven for 2 hours to obtain 26.1g of particles containing polymer F6.

[0319] Using air-dried particles containing polymer F6, the ion exchange capacity and TQ were determined according to the method described above.

[0320] Table 1 below summarizes the conditions in process 1 of each example, and Table 2 below summarizes the conditions, physical properties, and evaluation results in process 2 of each example.

[0321] [Table 1]

[0322]

[0323] [Table 2]

[0324]

[0325] As shown in Table 2, it can be confirmed that the manufacturing method of the fluoropolymer-containing particles according to the present invention can produce fluoropolymer-containing particles with low impurity content (Examples 1 to 4).

[0326] It should be noted that the entire contents of the specification, claims and abstract of Japanese Patent Application No. 2023-143764, filed on September 5, 2023, are incorporated herein as a disclosure of the present invention.

Claims

1. A method for manufacturing particles comprising a fluoropolymer, said fluoropolymer having groups capable of being converted into ion-exchange groups, wherein in the manufacturing method, After preparing the liquid composition comprising the fluoropolymer and the first solvent, The liquid composition is mixed with a second solvent to aggregate the fluoropolymer, forming particles containing the fluoropolymer, wherein the second solvent is an olefin having fluorine and chlorine atoms.

2. The method for manufacturing particles containing a fluoropolymer according to claim 1, wherein, The olefin has 3 carbon atoms.

3. The method for manufacturing particles containing a fluoropolymer according to claim 1 or 2, wherein, The standard boiling point of the olefin is 14~89℃.

4. The method for manufacturing particles containing a fluoropolymer according to claim 1 or 2, wherein, The fluoropolymer comprises tetrafluoroethylene-based units and units based on the compound shown in formula (1). Formula (1) CF2=CF-L-(A) n In formula (1), L is an optional perfluorocarbon group with an n+1 valence containing an ether oxygen atom, A is a group that can be converted into a sulfonic acid functional group, and n is 1 or 2.

5. The method for manufacturing particles containing a fluoropolymer according to claim 4, wherein, The first solvent comprises at least one selected from the group consisting of a compound represented by formula (1) and an organic solvent.

6. The method for manufacturing particles comprising a fluoropolymer according to claim 1 or 2, wherein, The mass ratio of the fluoropolymer content in the liquid composition to the content of the first solvent is 0.050 to 0.

43.

7. The method for manufacturing particles comprising a fluoropolymer according to claim 1 or 2, wherein, When the liquid composition is mixed with the second solvent, the mass ratio of the second solvent to the mass of the first solvent in the liquid composition is 1.0 to 8.

0.

8. The method for manufacturing particles comprising a fluoropolymer according to claim 1 or 2, wherein, The content of the first solvent is 70% by mass or more and 95% by mass or less relative to the total mass of the liquid composition.

9. The method for manufacturing particles comprising a fluoropolymer according to claim 1 or 2, wherein, The average particle size is above 38 μm and below 10,000 μm.

10. The method for manufacturing particles comprising a fluoropolymer according to claim 1 or 2, wherein, The mixing is performed using the liquid composition having a temperature of 20°C or higher and 60°C or lower, and the second solvent having a temperature of -15°C or higher and 30°C or lower.

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