Method for producing fluoropolymer and fluoropolymer

Abstract

[Solution] The present invention provides a method for producing a fluoropolymer, the method comprising: preparing an aqueous dispersion containing a fluoropolymer by carrying out emulsion polymerization of a fluoromonomer; adding a degradable surfactant to the aqueous dispersion; bringing the aqueous dispersion containing the degradable surfactant into contact with an adsorbent; then removing the adsorbent to recover the aqueous dispersion that has been brought into contact with the adsorbent; coagulating the fluoropolymer in the recovered aqueous dispersion; and drying the obtained coagulated product to obtain the fluoropolymer.

Description

Method for producing fluoropolymers and fluoropolymers

[0001] This disclosure relates to a method for producing fluoropolymers and to fluoropolymers themselves.

[0002] Patent Document 1 describes a method for producing an aqueous dispersion of a fluoropolymer containing a fluoropolymer, comprising: preparing an aqueous dispersion containing a fluoropolymer by polymerizing a fluoromonomer in the presence of a fluorine-containing surfactant and an aqueous medium; adding a nonionic surfactant to the obtained aqueous dispersion; adjusting the pH of the aqueous dispersion to 7 or higher; adjusting the temperature of the aqueous dispersion to 35°C or higher; and contacting the aqueous dispersion containing the nonionic surfactant with at least one treatment agent selected from the group consisting of ion exchange resins and adsorbents.

[0003] International Publication No. 2024 / 024917

[0004] The present disclosure aims to provide a manufacturing method that can produce fluoropolymers with low coloration and low content of specific fluorine-containing compounds and extractable organofluorine compounds.

[0005] According to this disclosure, a method for producing a fluoropolymer is provided, which involves preparing an aqueous dispersion containing a fluoropolymer by emulsion polymerization of a fluoromonomer, adding a degradable surfactant to the aqueous dispersion, contacting the aqueous dispersion containing the degradable surfactant with an adsorbent, then removing the adsorbent to recover the aqueous dispersion that has been in contact with the adsorbent, coagulating the fluoropolymer in the recovered aqueous dispersion, and drying the resulting coagulation to obtain the fluoropolymer.

[0006] This disclosure provides a manufacturing method that can produce fluoropolymers with less coloration and lower content of specific fluorine-containing compounds and extractable organofluorine compounds.

[0007] Before describing this disclosure in detail, we define or explain some of the terms used in this disclosure.

[0008] In this disclosure, fluororesin is a partially crystalline fluoropolymer and is a fluoroplastic. Fluororesin has a melting point and is thermoplastic, but may be melt-processable or non-melt-processable.

[0009] In this disclosure, melt processability means that the polymer can be melted and processed using conventional processing equipment such as extruders and injection molding machines. Therefore, melt processable fluororesins typically have a melt flow rate of 0.01 to 500 g / 10 min, as measured by the measurement method described later.

[0010] In this disclosure, fluororubber refers to an amorphous fluoropolymer. "Amorphous" means that the magnitude of the melting peak (ΔH) observed in 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. Fluororubber exhibits elastomeric properties by crosslinking. Elastomer properties refer to the ability of a polymer to be stretched and to retain its original length when the force required to stretch the polymer is no longer applied.

[0011] In this disclosure, polytetrafluoroethylene [PTFE] is preferably a fluoropolymer in which the content of tetrafluoroethylene units relative to the total polymerization units is 99 mol% or more.

[0012] In this disclosure, it is preferable that both the fluororesin (excluding polytetrafluoroethylene) and the fluororubber are fluoropolymers in which the tetrafluoroethylene content relative to the total polymerization units is less than 99 mol%.

[0013] In this 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 depending on the type of monomer.

[0014] In this disclosure, "organic group" means a group containing one or more carbon atoms, or a group formed by removing one hydrogen atom from an organic compound. The organic group is preferably an alkyl group which may have one or more substituents.

[0015] In this disclosure, the range represented by an endpoint includes all numerical values ​​that fall within that range (for example, 1 to 10 includes 1.4, 1.9, 2.33, 5.75, 9.98, etc.).

[0016] In this disclosure, the phrase "at least one" includes all numbers one or more (for example, at least two, at least four, at least six, at least eight, at least ten, at least 25, at least 50, at least 100, etc.).

[0017] The following describes specific embodiments of this disclosure in detail, but this disclosure is not limited to the embodiments described below.

[0018] 1. Manufacturing Method In the manufacturing method of the present disclosure, an aqueous dispersion containing a fluoropolymer is prepared by emulsion polymerization of a fluoromonomer, a biodegradable surfactant is added to the aqueous dispersion, the aqueous dispersion containing the biodegradable surfactant is brought into contact with an adsorbent, and then the adsorbent is removed to recover the aqueous dispersion that has been in contact with the adsorbent, the fluoropolymer in the recovered aqueous dispersion is coagulated, and the resulting coagulate is dried to obtain a fluoropolymer.

[0019] Patent Document 1 describes contacting an aqueous dispersion containing a nonionic surfactant with a treatment agent such as an ion exchange resin, and states that the nonionic surfactant is of general formula (i): R ６ -O-A １ -H (wherein, R ６ A is a linear or branched primary or secondary alkyl group having 8 to 18 carbon atoms. １ It has been proposed to use compounds represented by (where is a polyoxyalkylene chain). However, it has been found that when such conventional techniques are used, the resulting fluoropolymer becomes colored, and the color tone L* value of the fluoropolymer becomes small.

[0020] In the manufacturing method of this disclosure, a degradable surfactant is added to an aqueous dispersion, and the aqueous dispersion containing the degradable surfactant is brought into contact with an adsorbent. This allows the aqueous dispersion and the adsorbent to be brought into contact without impairing the dispersion stability of the primary particles of the fluoropolymer in the aqueous dispersion, and also suppresses the discoloration of the fluoropolymer, thereby enabling the production of a fluoropolymer with a high color L* value.

[0021] (Degradable surfactant) In the manufacturing method of the present disclosure, an aqueous dispersion containing a fluoropolymer is prepared by emulsion polymerization of a fluoromonomer, and then a degradable surfactant is added to the obtained aqueous dispersion.

[0022] As the degradable surfactant, at least one selected from the group consisting of acid hydrolyzable surfactants, base hydrolyzable surfactants, enzymatically degradable surfactants, and thermally degradable surfactants is preferred, and at least one selected from the group consisting of acid hydrolyzable surfactants and thermally degradable surfactants is more preferred.

[0023] In one embodiment, an acid hydrolyzable surfactant is used as the degradable surfactant.

[0024] An acid-hydrolyzable surfactant is a surfactant that, when an aqueous dispersion or aqueous solution containing 0.1% by mass of the acid-hydrolyzable surfactant is prepared with a pH of 7, and then the pH is adjusted to less than 3, and the surface tension changes by 50% or more after being left at 25°C for 2 hours. An acid-hydrolyzable surfactant is any compound whose surface tension changes by 50% or more; therefore, acid-hydrolyzable surfactants include not only compounds in which hydrolysis by acid can be actually observed, but also compounds in which hydrolysis by acid cannot be observed. Change in surface tension (%) = [(Surface tension of aqueous dispersion or aqueous solution after pH adjustment to less than 3) - (Surface tension of aqueous dispersion or aqueous solution at pH 7)] / (Surface tension of aqueous dispersion or aqueous solution at pH 7) × 100

[0025] In one embodiment, a basic hydrolyzable surfactant is used as the degradable surfactant.

[0026] A basic hydrolyzable surfactant is a surfactant that, when an aqueous dispersion or aqueous solution containing 0.1% by mass of the basic hydrolyzable surfactant is prepared with a pH of 7, and then the pH is adjusted to 10 or higher, and the solution is left at 25°C for 2 hours, exhibits a surface tension change of 50% or more. Surface tension change (%) = (Surface tension of the aqueous dispersion or aqueous solution after adjusting the pH to 10 or higher) / (Surface tension of the aqueous dispersion or aqueous solution at pH 7) × 100

[0027] In one embodiment, an enzymatically degradable surfactant is used as the degradable surfactant.

[0028] An enzymatically degradable surfactant is a surfactant that, when an aqueous dispersion or aqueous solution containing 0.1% by mass of the enzymatically degradable surfactant is prepared, and then an enzyme is added, and the solution is left at 25°C for 2 hours, the rate of change in surface tension is 50% or more. Rate of change in surface tension (%) = (Surface tension of the aqueous dispersion or aqueous solution after enzyme addition) / (Surface tension of the aqueous dispersion or aqueous solution before enzyme addition) × 100

[0029] In one embodiment, a thermally decomposable surfactant is used as the decomposable surfactant.

[0030] A thermally decomposable surfactant is defined as a surfactant whose residual percentage is 0 to 1% by mass after heating at 160°C for 1 hour, following the preparation of an aqueous dispersion or aqueous solution containing 30% by mass of the thermally decomposable surfactant, adjusting the pH of the prepared aqueous dispersion or aqueous solution to 7.0 or higher if the pH is below 7.0, and then heating. Residual percentage (by mass) = [(Mass of aqueous dispersion or aqueous solution before heating) - (Mass of aqueous dispersion or aqueous solution after heating)] / (Mass of aqueous dispersion or aqueous solution before heating) × 100

[0031] The degradable surfactant may be a degradable nonionic surfactant, a degradable anionic surfactant, a degradable cationic surfactant, or a degradable amphoteric surfactant, but at least one selected from the group consisting of degradable nonionic surfactants and degradable amphoteric surfactants is preferred, at least one selected from the group consisting of acid-degradable nonionic surfactants, acid-degradable amphoteric surfactants, and thermally degradable amphoteric surfactants is more preferred, and at least one selected from the group consisting of acid-degradable nonionic surfactants and thermally degradable amphoteric surfactants is even more preferred. Furthermore, it is preferable that the degradable surfactant is a surfactant that does not contain fluorine atoms.

[0032] The aqueous dispersion recovered after contact with the adsorbent contains a biodegradable surfactant. By using an acid-degradable nonionic surfactant as the biodegradable surfactant, and by performing coagulation of the fluoropolymer under acidic conditions using an aqueous dispersion containing the acid-degradable nonionic surfactant, the surfactant activity of the acid-degradable nonionic surfactant decreases, making it impossible for the primary particles of the fluoropolymer to disperse stably. As a result, the fluoropolymer can be rapidly coagulated, and furthermore, a coagulated product with a reduced content of the acid-degradable nonionic surfactant can be obtained.

[0033] In one embodiment, the degradable surfactant is a nonionic surfactant containing at least one Si. The degradable nonionic surfactant containing at least one Si may be an acid-degradable nonionic surfactant.

[0034] In one embodiment, the degradable surfactant is a nonionic surfactant having a siloxane bond (Si-O-Si bond). The nonionic surfactant having a siloxane bond may be an acid-degradable nonionic surfactant.

[0035] In one embodiment, the siloxane bond is represented by the following general formula: (In the formula, R ２１ The structure may be represented by (where H is independently or an organic group, and the wavy line represents a bond).

[0036] R ２１Independently, H, an alkyl group having 1 to 5 carbon atoms or a phenyl group is preferable, H or an alkyl group having 1 to 5 carbon atoms is more preferable, H or an alkyl group having 1 to 3 carbon atoms is further preferable, and H or a methyl group is even more preferable.

[0037] As the nonionic surfactant having a siloxane bond, the following general formula: (In the formula, R ２１ is independently H or an organic group, R ２２ is independently H or an organic group, R ２３ is a divalent group, R ２４ is a divalent organic group, R ２５ is H or an organic group, x is an integer of 0 to 30, y is an integer of 1 to 30, and z is an integer of 1 to 30) is preferable.

[0038] R ２１ Independently, in each occurrence, H, an alkyl group having 1 to 5 carbon atoms or a phenyl group is preferable, H or an alkyl group having 1 to 5 carbon atoms is more preferable, H or an alkyl group having 1 to 3 carbon atoms is further preferable, and H or a methyl group is even more preferable. R ２２ Independently, H, an alkyl group having 1 to 5 carbon atoms or a phenyl group is preferable, H or an alkyl group having 1 to 5 carbon atoms is more preferable, H or an alkyl group having 1 to 3 carbon atoms is further preferable, and H or a methyl group is even more preferable. R ２３ Independently, -C(=O)-, -O-, an alkylene group having 1 to 6 carbon atoms, or an oxyalkylene group having 1 to 6 carbon atoms is preferable, an alkylene group having 1 to 6 carbon atoms or an oxyalkylene group having 1 to 6 carbon atoms is more preferable, -(CH ２ ) ｎ１ -(n1 is an integer of 1 to 6) or -(CH ２ ) ｎ１ -O-(n1 is an integer of 1 to 6) is further preferable. R ２４ Independently, in each occurrence, an alkylene group having 1 to 6 carbon atoms is preferable, an ethylene group or a propylene group is more preferable, and an ethylene group (-(CH ２ -CH ２ -)) is even more preferable. R２５ Preferably, H or an alkyl group having 1 to 3 carbon atoms is used, and H or a methyl group is more preferred. x may be 0 or 1. y may be 1. z may be an integer from 5 to 30.

[0039] In one embodiment, the biodegradable surfactant is a biodegradable amphoteric surfactant.

[0040] Examples of biodegradable amphoteric surfactants include lauryldimethylaminoacetic acid betaine (C １２ H ２５ N ＋ (CH ３ ) ２ CH ２ COO － ), stearyldimethylaminoacetic acid betaine (C １８ H ３７ N ＋ (CH ３ ) ２ CH ２ COO － ), dodecylaminomethyldimethylsulfopropyl betaine (C １２ H ２５ N ＋ (CH ３ ) ２ (CH ２ ) ３ SO ３ － ), octadecylaminomethyldimethylsulfopropyl betaine (C １８ H ３７ N ＋ (CH ３ ) ２ (CH ２ ) ３ SO ３ － Alkyl betaine-type amphoteric surfactants such as (C) cocamidopropyl betaine (C) １１ H ２３ CONH(CH ２ ) ３ N ＋ (CH ３ ) ２ CH ２ COO － ), cocamidopropyl hydroxysultaine (C １１ H２３ CONH(CH ２ ) ３ N ＋ (CH ３ ) ２ CH ２ CH(OH)CH ２ SO ３ － ) and other fatty acid amide propyl betaine type amphoteric surfactants; 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine (RC ３ H ４ N ２ (C ２ H ４ (OH)CH ２ COO － ) and other alkyl imidazole type amphoteric surfactants; Sodium lauroyl glutamate (C １１ H ２３ [6]]CON(C ２ H ４ COOH)HCHCOONa), Potassium lauroyl glutamate (C １１ H ２３ CON(C ２ H ４ COOH)HCHCOOK), Lauroyl methyl-β-alanine (C １１ H ２３ CONH(C ２ H ４ COOCH ３ ) and other amino acid type amphoteric surfactants; Lauryl dimethylamine N-oxide (C １２ H ２５ N ＋ (CH ３ ) ２ O － ), Decyl dimethylamine N-oxide (C １０ H ２１ N ＋ (CH ３ ) ２ O － ), Oleyl dimethylamine N-oxide (C １８ H ３７ N ＋ (CH ３ ) ２ O － ) and other amine oxide type amphoteric surfactants; and the like can be mentioned.

[0041] Among the degradable amphoteric surfactants, amine oxide-type amphoteric surfactants are preferred, alkyldimethylamine oxides are preferred, alkyldimethylamine oxides having 10 to 22 carbon atoms are more preferred, and lauryldimethylamine N-oxide, decyldimethylamine N-oxide, or oleyldimethylamine N-oxide are even more preferred.

[0042] In one embodiment, the decomposable surfactant is a pyrodegradable amphoteric surfactant. When a pyrodegradable amphoteric surfactant is used, the aqueous dispersion recovered after contact with the adsorbent contains the pyrodegradable amphoteric surfactant. By coagulating the fluoropolymer in the aqueous dispersion containing the pyrodegradable amphoteric surfactant and drying the resulting coagulation by applying heat, a coagulation with a reduced content of the pyrodegradable amphoteric surfactant can be obtained.

[0043] Examples of pyrolytic amphoteric surfactants include those compounds exemplified as decomposable amphoteric surfactants that show the aforementioned residual percentages. Among these, amine oxide type amphoteric surfactants are preferred, alkyldimethylamine oxides are preferred, alkyldimethylamine oxides having 10 to 22 carbon atoms are more preferred, and lauryldimethylamine N-oxide, decyldimethylamine N-oxide, or oleyldimethylamine N-oxide are even more preferred.

[0044] In one embodiment, the degradable surfactant is cellulose, preferably water-soluble cellulose. The cellulose and water-soluble cellulose may be enzymatically degradable surfactants. The cellulose and water-soluble cellulose may be cellulose derivatives such as carboxymethylcellulose and hydroxypropylcellulose.

[0045] Other examples of biodegradable surfactants include surfactants with cyclic acetal bonds, such as surfactants with a 1,3-dioxolane ring, and surfactants with disulfide bonds.

[0046] The amount of biodegradable surfactant used is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1.0% by mass or more, still more preferably 2.0% by mass or more, particularly preferably 3.0% by mass or more, preferably 30% by mass or less, more preferably 20% by mass or less, still more preferably 10% by mass or less, and still more preferably 7.0% by mass or less, relative to the mass of the fluoropolymer in the aqueous dispersion.

[0047] The pH of the aqueous dispersion may be adjusted before adding the biodegradable surfactant. By bringing an aqueous dispersion containing a biodegradable surfactant and with an appropriately adjusted pH into contact with an adsorbent, the content of hydrophilic fluorine-containing compounds and extractable organofluorine compounds (EOFs) in the aqueous dispersion can be reduced with even greater efficiency.

[0048] When an acid hydrolyzable surfactant is used as the degradable surfactant, the pH of the aqueous dispersion that comes into contact with the adsorbent is preferably greater than 4.5, more preferably 5.0 or higher, even more preferably 6.0 or higher, preferably 14.0 or lower, more preferably 13.0 or lower, and even more preferably 11.0 or lower.

[0049] When a basic hydrolyzable surfactant is used as the degradable surfactant, the pH of the aqueous dispersion that comes into contact with the adsorbent is preferably 1.0 or higher, more preferably 2.0 or higher, even more preferably 3.0 or higher, preferably less than 9.0, and more preferably less than 8.0.

[0050] The pH can be adjusted by adding an alkali or acid to an aqueous dispersion.

[0051] (Adsorbent) In the manufacturing method of the present disclosure, a degradable surfactant is added to an aqueous dispersion, the aqueous dispersion containing the degradable surfactant is brought into contact with an adsorbent, and then the adsorbent is removed to recover the aqueous dispersion that has been in contact with the adsorbent.

[0052] The aqueous dispersion obtained by emulsion polymerization of fluoromonomers is of the general formula (12): [H-(CF ２) ｍ－１ CO ２ － ] M ＋ (In the formula, m is 12, M ＋ ∫ represents a cation. ∫ may contain hydrophilic fluorine-containing compounds such as those shown in ∫, and extractable organofluorine compounds (EOFs). By contacting an aqueous dispersion containing a biodegradable surfactant with an adsorbent, the content of hydrophilic fluorine-containing compounds and extractable organofluorine compounds (EOFs) in the aqueous dispersion can be reduced without impairing the dispersion stability of the primary particles of the fluoropolymer in the aqueous dispersion. As a result, fluoropolymers with reduced content of hydrophilic fluorine-containing compounds and extractable organofluorine compounds (EOFs) can be efficiently produced.

[0053] The adsorbent can be any material capable of adsorbing at least one of the compounds represented by the general formula (12): [H-(CF2)m-1CO2-]M+ (wherein m is 12 and M+ is a cation) and extractable organofluorine compounds (EOFs). Preferably, at least one selected from the group consisting of ion exchange resins, synthetic adsorbents, silica gel, polymer adsorbents, activated carbon, diatomaceous earth, and zeolites is preferred, more preferably ion exchange resins, synthetic adsorbents, and activated carbon, even more preferably ion exchange resins, and still more preferably anion exchange resins.

[0054] An anion exchange resin can be suitably used as the ion exchange resin. The anion exchange resin is the following general formula (A1): -N ＋ R １ R ２ R ３ X － (In the formula, R １ , R ２ and R ３ R is the same or different hydrogen atom or organic group. １ , R ２ and R ３ At least one of them is an organic group with 3 or more carbon atoms. X represents a counterion. An ion exchange group represented by the following general formula (A2): -NR ４ R ５ (In the formula, R ４and R ５ R is the same or different hydrogen atom or organic group. ４ and R ５ A resin having an ion exchange group represented by (at least one of which is an organic group with two or more carbon atoms) is preferred.

[0055] In general formula (A1), R １ , R ２ and R ３ R is either the same or different hydrogen atom or organic group. １ , R ２ and R ３ The group may consist entirely of organic groups, or it may consist of one hydrogen atom and two organic groups. Furthermore, it may consist of two hydrogen atoms and one organic group. The organic group has one or more carbon atoms. Preferably, the organic group has two or more carbon atoms. The above R １ , R ２ and R ３ One preferred form is an organic group having two or more carbon atoms.

[0056] In general formula (A1), R １ , R ２ and R ３ At least one of them is an organic group with 3 or more carbon atoms. １ , R ２ and R ３ Of these, one may be an organic group having 3 or more carbon atoms, and the other two may be hydrogen atoms or organic groups having 1 or 2 carbon atoms. Alternatively, two may be organic groups having 3 or more carbon atoms, and one may be a hydrogen atom or an organic group having 1 or 2 carbon atoms. R １ , R ２ and R ３ All of these may be organic groups having three or more carbon atoms.

[0057] R １ , R ２ and R ３ In this, the number of carbon atoms in the organic group is preferably 10 or less, more preferably 8 or less, and even more preferably 6 or less. The number of carbon atoms in the organic group may also be 5 or less.

[0058] In general formula (A1), R １ , R ２ and R ３Preferably, at least one of the components is an organic group with four or more carbon atoms. By adopting such a configuration, specific fluorine-containing compounds can be removed more efficiently.

[0059] R １ , R ２ and R ３ The organic group in is preferably an alkyl group, an alkanol group, or an alkenyl group, more preferably an alkyl group or an alkanol group, and even more preferably an alkyl group.

[0060] In this disclosure, "alkyl group" is a general term for the remaining groups after removing one hydrogen atom from an aliphatic saturated hydrocarbon, and includes linear or branched alkyl groups having one or more carbon atoms, or cyclic alkyl groups having three or more carbon atoms.

[0061] Furthermore, in this disclosure, "alkanol group" is a general term for the remaining group after removing one hydrogen atom from an alkanol, and includes linear or branched alkanol groups having one or more carbon atoms, or cyclic alkanol groups having three or more carbon atoms.

[0062] R １ , R ２ and R ３ R is the same or different alkyl group having 2 or more carbon atoms or an alkanol group having 1 or more carbon atoms. １ , R ２ and R ３ Preferably, at least one of them is an alkyl group having 3 or more carbon atoms.

[0063] R １ , R ２ and R ３ R is the same or different alkyl group having 2 or more carbon atoms or an alkanol group having 2 or more carbon atoms, １ , R ２ and R ３ A more preferred configuration is one in which at least one of the elements is an alkyl group having three or more carbon atoms.

[0064] R １ , R ２ and R ３Furthermore, R is either the same or different alkyl group having 2 or more carbon atoms or an alkanol group having 1 or more carbon atoms. １ , R ２ and R ３ A preferred configuration is that at least one of the elements is an alkyl group having four or more carbon atoms.

[0065] Also, R １ , R ２ and R ３ R is the same or different alkyl group having 2 or more carbon atoms or an alkanol group having 2 or more carbon atoms, １ , R ２ and R ３ A preferred configuration is that at least one of the elements is an alkyl group having four or more carbon atoms.

[0066] The alkyl group preferably has 10 or fewer carbon atoms, more preferably 8 or fewer, and even more preferably 6 or fewer. The alkyl group may also have 5 or fewer carbon atoms.

[0067] The number of carbon atoms in the alkanol group is preferably 10 or less, more preferably 8 or less, and even more preferably 6 or less. The number of carbon atoms in the alkanol group may also be 5 or less.

[0068] In general formula (A1), X is a counterion. X can be Cl, OH, Br, I, or NO. ３ SO ４ Examples include, and it is preferably Cl or OH. ４ In the case of a divalent anion, as shown above, one counterion coordinates to two repeating units of general formula (A1).

[0069] In general formula (A2), R ４ and R ５ R is the same or different hydrogen atom or organic group. ４ and R ５ At least one of them is an organic group with two or more carbon atoms. ４ and R ５ It may be entirely composed of organic groups. Alternatively, one may be a hydrogen atom and one may be an organic group.

[0070] In general formula (A2), R ４ and R５ At least one of them is an organic group with two or more carbon atoms.

[0071] R ４ and R ５ Of these, one may be an organic group having two or more carbon atoms, and the other may be a hydrogen atom or an organic group having one carbon atom. Also, R ４ and R ５ Both may be organic groups having two or more carbon atoms.

[0072] R ４ and R ５ At least one of these may be an organic group having 3 or more carbon atoms, or an organic group having 4 or more carbon atoms.

[0073] Also, R ４ and R ５ It is also preferable that the group is an organic group with two or more carbon atoms.

[0074] R ４ and R ５ In this, the number of carbon atoms in the organic group is preferably 10 or less, more preferably 8 or less, and even more preferably 6 or less. The number of carbon atoms in the organic group may also be 5 or less.

[0075] The above R ４ and R ５ The organic group in is preferably an alkyl group, an alkanol group, or an alkenyl group, more preferably an alkyl group or an alkanol group, and even more preferably an alkyl group.

[0076] R ４ and R ５ The above R is the same or different alkyl group or alkanol group, ４ and R ５ A more preferred form is that at least one of the members is an alkyl group having 2 or more carbon atoms or an alkanol group having 2 or more carbon atoms.

[0077] The alkyl group preferably has 10 or fewer carbon atoms, more preferably 8 or fewer, and even more preferably 6 or fewer. The alkyl group may also have 5 or fewer carbon atoms.

[0078] The number of carbon atoms in the alkanol group is preferably 10 or less, more preferably 8 or less, and even more preferably 6 or less. The number of carbon atoms in the above alkanol group may also be 5 or less.

[0079] The anion exchange resin is preferably one in which a group represented by general formula (A1) or a group represented by general formula (A2) is bonded to the resin matrix. An example of an anion exchange resin is one in which a group represented by general formula (A1) or a group represented by general formula (A2) is bonded to a resin matrix made of a styrene-based or acrylic polymer. The styrene-based or acrylic polymer as the resin matrix is ​​not limited, but for example, a resin matrix used in known anion exchange resins can be used. From the viewpoint of the removal efficiency of fluorine-containing compounds having hydrophilic groups, the resin matrix of the anion exchange resin is preferably styrene-based.

[0080] The basicity of anion exchange resins can be set in various ways depending on the type of polymer backbone and / or ion exchange group.

[0081] The anion exchange resin preferably has a pore diameter of 1 to 5000 Å. From the viewpoint of removal efficiency, a pore diameter of 50 Å or more is preferable, 100 Å or more is more preferable, and 150 Å or more is even preferable. It may also be 200 Å or more, or 250 Å or more. Furthermore, the pore diameter may be 1000 Å or less. The pore diameter can be calculated, for example, by measuring the specific surface area and total pore volume using the gas adsorption method.

[0082] From the viewpoint of removal efficiency, the anion exchange resin is preferably given a total exchange capacity of 0.1 eq / L-Resin or more. More preferably, it is 0.3 eq / L-Resin or more, even more preferably, 0.5 eq / L-Resin or more, and particularly preferably, 0.7 eq / L-Resin or more. Furthermore, the upper limit is preferably 5.0 eq / L-Resin or less, more preferably 3.0 eq / L-Resin or less, and particularly preferably 2.0 eq / L-Resin or less.

[0083] The moisture content of the anion exchange resin is preferably 20% by mass or more, more preferably 30 to 70% by mass, and even more preferably 35 to 65% by mass. A moisture content of 30% by mass or more in the anion exchange resin allows for efficient removal of the fluorine-containing compound. Furthermore, the fluorine-containing compound can easily diffuse into the particles of the anion exchange resin. If the moisture content of the anion exchange resin is 70% by mass or less, the decrease in the strength of the anion exchange resin particles due to insufficient crosslinking can be suppressed.

[0084] The moisture content of anion exchange resin can be measured by the following method. First, accurately measure 10 mL of the sample prepared in a reference form using a graduated cylinder. Wrap this resin in cloth and centrifuge to remove any adhering moisture, then quickly measure the mass of the resin. Next, dry the resin in a constant temperature drying oven at 105°C for 4 hours, then allow it to cool in a desiccator for 30 minutes. Measure the mass of the dried resin and calculate the moisture content using the following formula: Moisture content (mass%) = (Mass of resin before drying (g) - Mass of resin after drying (g)) / Mass of resin before drying (g) × 100

[0085] Anion exchange resins are typically spherical. The average particle size of the anion exchange resin is preferably 0.1 to 5 mm, more preferably 0.2 to 2 mm, and particularly preferably 0.3 to 1.5 mm. If the average particle size of the anion exchange resin is within the above range, the packed column of the anion exchange resin is less likely to become clogged. The above average particle size is a value obtained by sieving. Specifically, first, the anion exchange resin is placed in a sieve shaker and the particle size distribution is measured by sieving. Then, the diameter of the sieve corresponding to 50% of the residual classifier is determined and this is taken as the average particle size.

[0086] Commercially available anion exchange resins can be used, such as PFA694E and A592E from Purolite Co., Ltd., AMBERLITE PSR2 PLUS from Organo Corporation, Muromachi Chemical Co., Ltd., and Lewatit TP108 DW and Lewatit MonoPlus TP109 from Lanxess.

[0087] Furthermore, a resin having an ion exchange group (excluding the group represented by the general formula (A1) and the group represented by the general formula (A2) above) can also be used as the anion exchange resin. Examples of such anion exchange resins include a resin having at least one ion exchange group selected from the group consisting of amino groups and quaternary ammonium groups (excluding the group represented by the general formula (A1) and the group represented by the general formula (A2) above). An example of such an anion exchange resin is the following general formula (B1): -N ＋ (CH ３ ) ３ X － A group represented by (wherein X represents the counterion) or the following general formula (B2): -N ＋ (CH ３ ) ２ (C ２ H ４ OH)X － A group represented by the formula (wherein X represents a counterion) is preferred. In general formulas (B1) and (B2), X can be Cl, OH, Br, I, or NO. ３ SO ４ Examples include, and it is preferably Cl or OH. ４ In the case of a divalent anion, as shown above, one counterion coordinates to two repeating units of general formula (A1).

[0088] The anion exchange resin preferably has ion exchange groups (excluding the groups represented by general formula (A1) and general formula (A2)) bonded to a resin matrix, and examples of the resin matrix include styrene-based or acrylic polymers. The styrene-based or acrylic polymer used as the resin matrix is ​​not limited, but for example, resin matrices used in known anion exchange resins can be used. From the viewpoint of the removal efficiency of fluorine-containing compounds having hydrophilic groups, it is preferable that the resin matrix of anion exchange resin B is styrene-based.

[0089] The resin having ion exchange groups (excluding the groups represented by general formula (A1) and general formula (A2) above) may be weakly basic or strongly basic. Preferably, it is a strongly basic anion exchange resin. The basicity of the anion exchange resin can be set in various ways depending on the polymer backbone and / or the type of ion exchange groups.

[0090] Resins having ion exchange groups (excluding the groups represented by the general formula (A1) and the general formula (A2) above) preferably have a pore diameter of 1 to 5000 Å. From the viewpoint of removal efficiency, a pore diameter of 50 Å or more is preferable, 100 Å or more is more preferable, and 150 Å or more is even preferable. It may also be 200 Å or more, or 250 Å or more. Furthermore, the pore diameter may be 1000 Å or less. The pore diameter can be calculated, for example, by measuring the specific surface area and total pore volume using the gas adsorption method.

[0091] Resins having ion exchange groups (excluding the groups represented by general formula (A1) and general formula (A2) above) are preferably such that, from the viewpoint of removal efficiency, the total exchange capacity is 0.1 eq / L-Resin or more. More preferably, it is 0.3 eq / L-Resin or more, even more preferably, 0.5 eq / L-Resin or more, and particularly preferably, 0.7 eq / L-Resin or more. Furthermore, a larger total exchange capacity is preferable, but for example, the upper limit is preferably 5.0 eq / L-Resin, more preferably 3.0 eq / L-Resin or less, and particularly preferably 2.0 eq / L-Resin or less.

[0092] The moisture content of the resin having ion exchange groups (excluding the groups represented by general formula (A1) and general formula (A2) above) is preferably 20% by mass or more, more preferably 30 to 70% by mass, and even more preferably 35 to 65% by mass.

[0093] Resins having ion exchange groups (excluding the groups represented by the general formula (A1) and the general formula (A2) above) are usually spherical. The average particle size of the resin having ion exchange groups (excluding the groups represented by the general formula (A1) and the general formula (A2) above) is preferably 0.1 to 5 mm, more preferably 0.2 to 2 mm, and particularly preferably 0.3 to 1.5 mm. If the average particle size is within the above range, the packed column of the anion exchange resin is less likely to become clogged. The above average particle size is a value obtained by the sieving method. Specifically, first, the anion exchange resin is placed in a sieve shaker and the particle size distribution is measured by sieving. Then, the diameter of the sieve corresponding to 50% of the residual classification is determined and this is taken as the average particle size.

[0094] As the resin having ion exchange groups (excluding the groups represented by the general formula (A1) and the general formula (A2) above), commercially available products may be used. For example, the Diaion® SA series from Mitsubishi Chemical Corporation, A400, A300, etc. from Purolite Corporation, and the Amberlite® series, IRA4002OH, etc. from DuPont, can be used.

[0095] As the ion exchange resin, at least one selected from the group consisting of a resin in which a group represented by general formula (B1) is bonded to a styrene-based polymer, and a resin in which a group represented by general formula (B2) is bonded to a styrene-based polymer, is preferred. Among these, OH is preferred as X in general formulas (B1) and (B2).

[0096] Synthetic adsorbents can be used as adsorbents. Synthetic adsorbents are porous resins that do not have ion exchange groups, and known synthetic adsorbents can be used. Examples of ion exchange groups include amino groups, quaternary ammonium groups, carboxylic acid groups, sulfonic acid groups, etc. Specific examples of synthetic adsorbents include styrene resins such as styrene-divinylbenzene copolymers, acrylic resins such as (meth)acrylic acid ester-ethylene glycol dimethacrylate copolymers, methacrylic resins, polyvinyl resins, dextran resins, etc. Commercially available synthetic adsorbents include, specifically, styrene-based resins such as Diaion HP10, Diaion HP20, Diaion HP21, Diaion HP40, Diaion HP50, Sepapies SP207, Sepapies SP70, Sepapies SP825, Sepapies SP850, Sepapies SP207 (all manufactured by Mitsubishi Chemical Corporation), Amberlite XAD1180N, Amberlite XAD2000, Amberlite XAD4, Amberlite FPX66 (all manufactured by Organo Corporation), etc.; and acrylic-based resins such as Diaion HP2MG (manufactured by Mitsubishi Chemical Corporation) and Amberlite HXAD-7HP (manufactured by Organo Corporation), etc.

[0097] The synthetic adsorbent preferably has a pore diameter of 1 to 5000 Å. From the viewpoint of removal efficiency, a pore diameter of 50 Å or more is preferable, 100 Å or more is more preferable, and 150 Å or more is even preferable. It may also be 200 Å or more, or 250 Å or more. Furthermore, the pore diameter may be 1000 Å or less. The pore diameter can be calculated, for example, by measuring the specific surface area and total pore volume using a gas adsorption method.

[0098] Synthetic adsorbents have a specific surface area of ​​300 m². ２ It is preferable that the amount is 1 / g or more. The specific surface area is 400 m². ２ More preferably 500m / g or more. ２ More preferably 600m / g or more. ２ A value of 1 / g or more is particularly preferable. There is no upper limit to the specific surface area, but for example, 2000 m² is preferable. ２ It may be less than or equal to / g, and 1500m ２It may be less than or equal to / g, and 1000m ２ The amount may be less than or equal to / g. Furthermore, the synthetic adsorbent is usually spherical, and the average particle size of the synthetic adsorbent is preferably 0.1 to 2.0 mm, more preferably 0.2 to 1.5 mm, even more preferably 0.2 to 1.3 mm, and particularly preferably 0.3 to 1.0 mm, from the viewpoint of removal efficiency. The average particle size of the synthetic adsorbent refers to the 50% mass value obtained by plotting the integrated mass after classification by sieving on a graph.

[0099] From the viewpoint of improving removal efficiency, synthetic adsorbents preferably contain water. The water content is preferably 20 to 80% by mass, more preferably 40 to 75% by mass, and particularly preferably 50 to 70% by mass.

[0100] Activated carbon can be produced from carbonaceous materials. Examples of carbonaceous materials include any material that produces activated carbon through carbonization or activation, such as wood, sawdust, charcoal, fruit shells like coconut shells and walnut shells, plant-based materials like fruit seeds, coal such as peat, lignite, brown coal, bituminous coal, and anthracite, pitch such as petroleum pitch and coal pitch, tar such as coke, coal tar, and petroleum tar, mineral-based materials such as petroleum distillation residues, natural materials such as cotton and rayon cellulose fibers, and synthetic materials such as phenolic resins, polyvinyl alcohol, and polyacrylonitrile. The material can be in powder, granular, or fibrous form, or molded from these forms.

[0101] Activated carbon has a specific surface area of ​​500 m². ２ It is preferable that the amount is 1 / g or more. The specific surface area is 1000 m². ２ More preferably 1500m / g or more, ２ More preferably 1800m / g or more. ２ A value of 1 / g or more is particularly preferred, and 2000m ２ A value of 1 / g or more is particularly preferred. There is no upper limit to the specific surface area, but for example, 2500 m² is preferable. ２The amount may be / g. The shape of the activated carbon is not particularly limited and may be, for example, pelletized, granular, powdered, or spherical particles. The activated carbon may be a commercially available product. Examples of commercially available activated carbon include Shirasagi (trademark) from Osaka Gas Chemical Co., Ltd., Filtrasorb (trademark) CAL, Diahope (trademark), Diasorb (trademark) from Calgon Carbon Japan Co., Ltd., and the Evadia (trademark) series from Sui-ing Co., Ltd.

[0102] Activated carbon preferably has improved adsorption performance due to steam activation treatment. In the steam activation treatment, it is preferable to expose the activated carbon to steam at a temperature of 120°C or higher, for example 130 to 350°C, particularly 150 to 1000°C, and a pressure of 0.2 MPa or higher, for example 0.5 to 15 MPa, particularly 1 to 15 MPa. The steam activation treatment time is generally 10 seconds to 50 hours, for example 10 minutes to 10 hours. Heating in a furnace may be performed during activation.

[0103] Cations may be impregnated onto the surface of activated carbon. Examples of cations include metal ions, metal oxide ions, and ammonium ions. Examples of metals include metal atoms from groups 1 to 13 of the periodic table (e.g., alkali metals (e.g., Li, Na, K), alkaline earth metals (e.g., Mg, Ca), Ti, Zr, V, Cr, Fe, Ni, Cu, Zn).

[0104] The contact area (surface area) of the adsorbent is preferably 0.0020 m² relative to the mass of the fluoropolymer in the aqueous dispersion. ２ It is 0.0030 m / g or more, and more preferably 0.0030 m ２ It is 1 / g or more, and more preferably 0.0040m ２ The amount is 0.0050 m / g or more, and is particularly preferred. ２ The value is 1 / g or more, and there is no particular upper limit, but for example, 5.0 m ２ It may be less than or equal to / g.

[0105] The exchange capacity of the ion exchange resin is preferably 0.25 meq / g or more, preferably 0.50 meq / g or more, preferably 1.00 meq / g or more, and preferably 1.50 meq / g or more, relative to the mass of the fluoropolymer in the aqueous dispersion. There is no particular upper limit, but for example, it may be 2500 meq / g or less.

[0106] The amount of adsorbent to be brought into contact with the aqueous dispersion is preferably 10,000 g or less, preferably 0.1 g or more, more preferably 1 g or more, even more preferably 5 g or more, even more preferably 10 g or more, and particularly preferably 100 g or more, per 1,000 g of fluoropolymer in the aqueous dispersion.

[0107] The method of contacting the aqueous dispersion with the adsorbent may be batch-type or fluid-type.

[0108] The number of times the aqueous dispersion and the adsorbent are brought into contact may be once or two or more times. By repeating the contact between the aqueous dispersion and the adsorbent two or more times, the content of hydrophilic fluorine-containing compounds and the content of extractable organofluorine compounds in the aqueous dispersion can be further reduced. The number of times the aqueous dispersion and the adsorbent are brought into contact may be 10 times or less.

[0109] Conventional methods can be used to bring the aqueous dispersion and the adsorbent into contact. For example, this can be done by adding the adsorbent to the aqueous dispersion and stirring, or by the column method, in which the aqueous dispersion is flowed through a column packed with the adsorbent. The packed column used in the column method may be a mobile, fixed-bed, or fluidized-bed type.

[0110] After bringing the aqueous dispersion into contact with the adsorbent, the aqueous dispersion and the adsorbent can be separated, and the aqueous dispersion can be recovered.

[0111] When using a method in which an adsorbent is added to an aqueous dispersion and stirred, the adsorbent and aqueous dispersion are separated after contact. The method for separating the adsorbent and aqueous dispersion is not limited and can be, for example, by filtration.

[0112] (Coagulation) In the manufacturing method of the present disclosure, after removing the adsorbent from the aqueous dispersion, the fluoropolymer in the recovered aqueous dispersion is coagulated to obtain the fluoropolymer. Furthermore, the obtained coagulation can be dried to obtain a fluoropolymer powder. The coagulation may be washed before drying.

[0113] Coagulation of fluoropolymers can be carried out, for example, by diluting an aqueous dispersion with water to a polymer concentration of 1 to 20% by mass or 5 to 20% by mass, and, if necessary, adjusting the pH to neutral or alkaline, then stirring more vigorously than during the reaction in a container equipped with a stirrer. Coagulation of the fluoropolymer can also be carried out by stirring while adding water-soluble organic compounds such as methanol and acetone, inorganic salts such as potassium nitrate and ammonium carbonate, or inorganic acids such as hydrochloric acid, sulfuric acid, and nitric acid as coagulating agents. The above coagulation may also be carried out continuously using an in-line mixer or the like.

[0114] In one embodiment, the method includes a step of adjusting the pH of an aqueous dispersion containing an acid-hydrolyzable surfactant to a level in which at least a portion of the acid-hydrolyzable surfactant can be decomposed. In another embodiment, by adding an acid such as an inorganic acid to an aqueous dispersion containing an acid-hydrolyzable surfactant to adjust the pH of the aqueous dispersion to 4.5 or less, and stirring the aqueous dispersion, the fluoropolymer in the aqueous dispersion can be coagulated. After adjusting the pH of the aqueous dispersion to 4.5 or less, a base may be added to the aqueous dispersion to coagulate the fluoropolymer in the aqueous dispersion. When an acid-hydrolyzable surfactant is added to an aqueous dispersion and the aqueous dispersion containing the acid-hydrolyzable surfactant is brought into contact with an adsorbent, the resulting aqueous dispersion contains the acid-hydrolyzable surfactant. By adjusting the pH of the aqueous dispersion to 4.5 or less using an acid and coagulating the fluoropolymer, at least a portion of the acid-hydrolyzable surfactant can be decomposed before or during coagulation, resulting in a reduced acid-hydrolyzable surfactant content and a fluoropolymer with less coloration.

[0115] In one embodiment, the method includes a step of adjusting the pH of an aqueous dispersion containing a basic hydrolyzable surfactant to a level in which at least a portion of the basic hydrolyzable surfactant can be decomposed. In another embodiment, by adding alkali to an aqueous dispersion containing a basic hydrolyzable surfactant to adjust the pH of the aqueous dispersion to 9.0 or higher, and stirring the aqueous dispersion, the fluoropolymer in the aqueous dispersion can be coagulated. After adjusting the pH of the aqueous dispersion to 9.0 or higher, an acid may be added to the aqueous dispersion to coagulate the fluoropolymer in the aqueous dispersion. When a basic hydrolyzable surfactant is added to an aqueous dispersion and the aqueous dispersion containing the basic hydrolyzable surfactant is brought into contact with an adsorbent, the resulting aqueous dispersion contains the basic hydrolyzable surfactant. By adjusting the pH of the aqueous dispersion to 9.0 or higher, and then coagulating the fluoropolymer in the aqueous dispersion, at least a portion of the basic hydrolyzable surfactant can be decomposed before or during coagulation, resulting in a fluoropolymer with a reduced basic hydrolyzable surfactant content and less coloration.

[0116] In one embodiment, the method includes a step of adding an enzyme capable of degrading at least a portion of the enzymatically degradable surfactant to an aqueous dispersion containing an enzymatically degradable surfactant. In one embodiment, by adding an enzyme to an aqueous dispersion containing an enzymatically degradable surfactant and stirring the aqueous dispersion, the fluoropolymer in the aqueous dispersion can be coagulated. In addition to the enzyme, an acid or base may be added to the aqueous dispersion to coagulate the fluoropolymer in the aqueous dispersion. When an enzymatically degradable surfactant is added to an aqueous dispersion and the aqueous dispersion containing the enzymatically degradable surfactant is brought into contact with an adsorbent, the resulting aqueous dispersion contains the enzymatically degradable surfactant. By adding an enzyme and then coagulating the fluoropolymer in the aqueous dispersion, at least a portion of the enzymatically degradable surfactant can be degraded before or during coagulation, resulting in a reduced content of the enzymatically degradable surfactant and a fluoropolymer with less coloration.

[0117] In one embodiment, if the pH of the aqueous dispersion containing a thermally decomposable surfactant is below 7.0, an alkali can be added to adjust the pH to 7.0 or higher, and the aqueous dispersion can be stirred to cause coagulation of the fluoropolymer in the aqueous dispersion. That is, when using a thermally decomposable surfactant, it is preferable that the pH of the aqueous dispersion at the time of coagulation be 7.0 or higher. By adjusting the pH of the aqueous dispersion to 7.0 or higher and then causing coagulation of the fluoropolymer in the aqueous dispersion, at least a portion of the thermally decomposable surfactant can be decomposed during drying, resulting in a fluoropolymer with a reduced thermally decomposable surfactant content and less coloration.

[0118] In one embodiment, a fluoropolymer in an aqueous dispersion can be coagulated in the presence of at least one surfactant selected from the group consisting of biodegradable amphoteric surfactants and biodegradable cationic surfactants. These surfactants are preferably surfactants that do not contain fluorine atoms. By coagulating the fluoropolymer in the presence of at least one surfactant selected from the group consisting of biodegradable amphoteric surfactants and biodegradable cationic surfactants, a fluoropolymer that is less prone to static charge can be obtained. In this disclosure, the static charge of a fluoropolymer can be confirmed, for example, by bringing the fluoropolymer powder into contact with polyethylene and then measuring the surface potential of the fluoropolymer powder using an electrostatic meter. Alternatively, the static charge of a fluoropolymer can also be confirmed by measuring its static properties in accordance with JIS C61340-2-2.

[0119] In one embodiment, a fluoropolymer in an aqueous dispersion can be coagulated in the presence of a biodegradable amphoteric surfactant. A thermally biodegradable amphoteric surfactant is more preferred as the biodegradable amphoteric surfactant. By using a biodegradable amphoteric surfactant, preferably a thermally biodegradable amphoteric surfactant, it is possible to obtain a fluoropolymer that has less coloration, a low content of specific fluorine-containing compounds and extractable organofluorine compounds, and is less prone to static charge.

[0120] Examples of biodegradable amphoteric surfactants and thermally decomposable amphoteric surfactants include those mentioned above.

[0121] To coagulate a fluoropolymer in the presence of a degradable amphoteric surfactant and / or a degradable cationic surfactant, the adsorbent can be removed from the aqueous dispersion, and then the degradable amphoteric surfactant and / or a degradable cationic surfactant can be added to the recovered aqueous dispersion. Furthermore, if an aqueous dispersion containing a degradable amphoteric surfactant and / or a degradable cationic surfactant is brought into contact with an adsorbent, and these surfactants remain in the recovered aqueous dispersion, coagulation may be carried out in the presence of the residual surfactant, or additional surfactants may be added in addition to the residual surfactant before coagulation.

[0122] The amount of at least one surfactant selected from the group consisting of degradable amphoteric surfactants and degradable cationic surfactants used during coagulation is preferably 0.01 to 5.00% by mass, more preferably 0.03% by mass or more, even more preferably 0.05% by mass or more, even more preferably 4.00% by mass or less, and even more preferably 3.50% by mass or less, relative to the mass of the fluoropolymer in the aqueous dispersion. When a degradable amphoteric surfactant and / or a degradable cationic surfactant are used when contacting the aqueous dispersion with the adsorbent, if these surfactants remain in the aqueous dispersion subjected to coagulation, the amount of surfactant added during coagulation can be adjusted considering the amount of residual surfactant.

[0123] It is preferable to obtain a wet powder by recovering the coagulation material produced by the coagulation of the fluoropolymer, and then wash the wet powder. The washing may be done once or two or more times. Washing further reduces the content of biodegradable surfactants, and a fluoropolymer with even less coloration can be obtained.

[0124] As for the cleaning method, at least one cleaning method selected from the group consisting of cleaning by stirring, ultrasonic cleaning, cleaning using ultrafine bubbles, cleaning using alkali, cleaning using acid, and cleaning using a radical generator is preferred.

[0125] After washing the wet powder, the washed wet powder can be dried.

[0126] The drying temperature is preferably 10 to 280°C. The drying temperature may be 100°C or higher, 120°C or higher, 130°C or higher, 140°C or higher, 150°C or higher, or 160°C or higher. The drying temperature may be 230°C or lower, 210°C or lower, 200°C or lower, 190°C or lower, 185°C or lower, or 180°C or lower. According to the manufacturing method of this disclosure, even when drying is performed at such relatively low temperatures, it is possible to obtain a fluoropolymer with little discoloration and low content of specific fluorine-containing compounds and extractable organofluorine compounds, and to produce a fluoropolymer that can be extruded at low and stable extrusion pressures.

[0127] The drying time is preferably 5 to 3000 minutes. The drying time may be 10 minutes or more, 15 minutes or more, 20 minutes or more, 30 minutes or more, 50 minutes or more, 100 minutes or more, 150 minutes or more, or 200 minutes or more. The drying time may be 2500 minutes or less, or 2000 minutes or less. By drying the wet powder within the above drying time, the content of degradable surfactants is further reduced, and a fluoropolymer with even less coloration can be obtained.

[0128] (Aqueous dispersion) The aqueous dispersion used in the manufacturing method of this disclosure can be prepared by emulsion polymerization of fluoromonomers.

[0129] The aqueous dispersion obtained by emulsion polymerization of fluoromonomers is of the general formula (12): [H-(CF ２ ) ｍ－１ CO ２ － ] M ＋ (In the formula, m is 12, M ＋The '∫' represents a cation. The fluoropolymer may contain hydrophilic fluorine-containing compounds such as those represented by '∫', and extractable organofluorine compounds (EOFs). By using the manufacturing method of this disclosure, it is possible to produce fluoropolymers in which the content of hydrophilic fluorine-containing compounds and extractable organofluorine compounds (EOFs) is reduced.

[0130] (Aqueous medium) In one embodiment, polymerization of fluoromonomers is carried out in the presence of an aqueous medium.

[0131] The aqueous medium is a reaction medium for 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 ether or ketone, and / or a fluorine-containing organic solvent with a boiling point of 40°C or lower.

[0132] As an aqueous medium, an aqueous medium containing only water, or an aqueous medium containing only water and a fluorine-free organic solvent, is preferred because it allows polymerization to proceed smoothly, and an aqueous medium containing only water is more preferred.

[0133] The water content in the aqueous medium is preferably 90% by mass or more, more preferably 95% by mass or more, even more preferably 99.0% by mass or more, even more preferably 99.5% by mass or more, particularly preferably 99.9% by mass or more, and may be 100% by mass, in order to facilitate polymerization.

[0134] (Polymerization initiator) In one embodiment, polymerization of a fluoromonomer is carried out in the presence of a polymerization initiator.

[0135] Examples of polymerization initiators include water-soluble radical polymerization initiators. Water-soluble radical polymerization initiators may be known water-soluble peroxides, such as ammonium salts, potassium salts, and sodium salts of persulfuric acid, perboric acid, perchloric acid, superphosphate, and percarbonate; organic peroxides such as disuccinate peroxide and diglutaric acid peroxide; t-butyl permalate; and t-butyl hydroperoxide. Among these, persulfates are preferred, and potassium persulfate (K) is particularly preferred.２ S ２ O ８ ), ammonium persulfate ((NH ４ ) ２ S ２ O ８ ), sodium persulfate (Na ２ S ２ O ８ ) is more preferable, and ammonium persulfate is even more preferable.

[0136] Furthermore, oil-soluble radical polymerization initiators can be used as polymerization initiators. The oil-soluble radical polymerization initiator may be a known oil-soluble peroxide, such as dialkyl peroxycarbonates such as diisopropyl peroxydicarbonate and disec-butyl peroxydicarbonate, peroxyesters such as t-butyl peroxyisobutyrate and t-butyl peroxypivalate, and dialkyl peroxides such as di-t-butyl peroxide. Also, di(ω-hydro-dodecafluoroheptanoyl) peroxide, di(ω-hydro-tetradecafluoroheptanoyl) peroxide, di(ω-hydro-hexadecafluorononanoyl) peroxide, di(perfluorobutyryl) peroxide, di(perfluorovaleryl) peroxide, di(perfluorohexanoyl) peroxide, di(perfluoroheptanoyl) peroxide, di(perfluorooctanoyl) peroxide, di(perfluorononanoyl) peroxide, and di(ω-chloro Representative examples include di[perfluoro(or fluorochloro)acyl]peroxides such as (lo-hexafluorobutyryl) peroxide, di(ω-chloro-decafluorohexanoyl) peroxide, di(ω-chloro-tetradecafluorooctanoyl) peroxide, ω-hydro-dodecafluoroheptanoyl-ω-hydrohexadecafluorononanoyl-peroxide, ω-chloro-hexafluorobutyryl-ω-chloro-decafluorohexanoyl-peroxide, ω-hydrododecafluoroheptanoyl-perfluorobutyryl-peroxide, di(dichloropentafluorobutanoyl) peroxide, di(trichlorooctafluorohexanoyl) peroxide, di(tetrachloroundafluorooctanoyl) peroxide, di(pentachlorotetradecafluorodecanoyl) peroxide, and di(undachlorodotriacontafluorodocosanoyl) peroxide.

[0137] Furthermore, a redox initiator, which combines an oxidizing agent and a reducing agent, can be used as a polymerization initiator.

[0138] Examples of oxidizing agents include persulfates, organic peroxides, potassium permanganate, manganese triacetate, and ammonium cerium nitrate. Examples of reducing agents include sulfites, bisulfites, bromates, diimines, and oxalic acid. Examples of persulfates include ammonium persulfate and potassium persulfate. Examples of sulfites include sodium sulfite and ammonium sulfite. To increase the decomposition rate of the initiator, it is also preferable to add copper salts and iron salts to the redox initiator combination. Examples of copper salts include copper(II) sulfate, and examples of iron salts include iron(II) sulfate.

[0139] Examples of the redox initiators mentioned above include potassium permanganate / oxalic acid, potassium permanganate / ammonium oxalate, ammonium persulfate / bisulfite / ferrous sulfate, ammonium persulfate / ammonium sulfite, manganese triacetate / oxalic acid, cerium ammonium nitrate / oxalic acid, bromate / bisulfite, etc., with potassium permanganate / oxalic acid and ammonium persulfate / bisulfite / ferrous sulfate being preferred. When using a redox initiator, either an oxidizing agent or a reducing agent may be charged into the polymerization tank beforehand, and then the other may be added continuously or intermittently to initiate polymerization. For example, when using potassium permanganate / oxalic acid, it is preferable to charge oxalic acid into the polymerization tank and then continuously add potassium permanganate thereto.

[0140] There are no particular limitations on the amount of polymerization initiator used, but it is sufficient to add at least an amount that does not significantly reduce the polymerization rate (for example, a few ppm relative to water concentration) in a lump sum at the beginning of polymerization, or sequentially or continuously. The upper limit is a range in which the reaction temperature can be increased while removing heat from the apparatus surface using the heat of the polymerization reaction, and a more preferable upper limit is a range in which the heat of the polymerization reaction can be removed from the apparatus surface.

[0141] The amount of polymerization initiator used is preferably 0.00001 to 10% by mass, more preferably 0.0001% by mass or more, even more preferably 0.001% by mass or more, still more preferably 0.01% by mass or more, preferably 5% by mass or less, and more preferably 2% by mass or less, relative to the aqueous medium.

[0142] (Chain transfer agent) In one embodiment, polymerization of fluoromonomers can be carried out in the presence of a chain transfer agent.

[0143] Examples of chain transfer agents include esters such as dimethyl malonate, diethyl malonate, methyl acetate, ethyl acetate, butyl acetate, and dimethyl succinate, as well as various halogenated hydrocarbons such as isopentane, methane, ethane, propane, butane, pentane, hexane, heptane, methanol, isopropanol, acetone, various mercaptans, and carbon tetrachloride, and cyclohexane. Among these, at least one selected from the group consisting of hydrocarbon compounds and alcohols is preferred as a chain transfer agent, with isopentane, methane, ethane, propane, butane, pentane, hexane, heptane, methanol, and isopropanol being more preferred.

[0144] The amount of the above-mentioned chain transfer agent used is usually 1 to 50,000 ppm by mass, preferably 1 to 20,000 ppm by mass, relative to the total amount of fluoromonomer supplied.

[0145] (Nucleating agent) In one embodiment, polymerization of fluoromonomers can be carried out in the presence of a nucleating agent. In particular, by adding a nucleating agent in the early stages of polymerization, the average primary particle size of the particles contained in the aqueous dispersion is reduced, and an aqueous dispersion with excellent stability can be obtained.

[0146] Examples of nucleating agents include monocarboxylic acids, dicarboxylic acids, perfluoropolyether (PFPE) acids or their salts, and hydrocarbon-containing surfactants. Preferably, at least one selected from the group consisting of monocarboxylic acids, dicarboxylic acids, perfluoropolyether (PFPE) acids or their salts, and fluorine-free nonionic surfactants is used.

[0147] Among the nucleating agents, fluorine-free nonionic surfactants are preferred. Fluorine-free nonionic surfactants preferably do not contain aromatic moieties.

[0148] Examples of fluorine-free nonionic surfactants include nonionic surfactants represented by general formula (i) and nonionic surfactants represented by general formula (ii). ６ -O-A １ -H (i) (wherein, R ６ A is a linear or branched primary or secondary alkyl group having 8 to 18 carbon atoms. １ (This is a polyoxyalkylene chain.) ７ -C ６ H ４ -O-A ２ -H (ii) (wherein, R ７ A is a linear or branched alkyl group having 4 to 12 carbon atoms. ２ (This is a polyoxyalkylene chain.)

[0149] As the fluorine-free nonionic surfactant, at least one selected from the group consisting of nonionic surfactants represented by general formula (i) and nonionic surfactants represented by general formula (ii) is preferred, and the nonionic surfactant represented by general formula (i) is more preferred.

[0150] Examples of fluorine-free nonionic surfactants include Dow Chemical Company's Triton® X series (X15, X45, X100, etc.), Tergitol® 15-S series, Tergitol® TMN series (TMN-6, TMN-10, TMN-100, etc.), Tergitol® L series, and BASF's Pluronic® R series (31R1, 17R2, 10R5, 25R4, Examples include m-22, n-23), Iconol® TDA series (TDA-6, TDA-9, TDA-10), Clariant's Genapol series (X080, etc.), Daiichi Kogyo Seiyaku's Neugen TDS series (TDS-80, TDS-100, etc.), Lion Corporation's Leocol TD series (TD-90, etc.), Lion Corporation's Lionol® TD series, Harcross Chemicals' T-Det A series (A-138, A-139, A-1315, etc.), and Nippon Oil & Fats Co., Ltd.'s Dispanol TOC.

[0151] The amount of nucleating agent used can be appropriately selected depending on the type of nucleating agent. The amount of nucleating agent used may be 5000 ppm by mass or less relative to the aqueous medium, preferably 1000 ppm by mass or less, more preferably 500 ppm by mass or less, even more preferably 100 ppm by mass or less, particularly preferably 50 ppm by mass or less, most preferably 10 ppm by mass or less, preferably 0.01 ppm by mass or more, and more preferably 0.1 ppm by mass or more.

[0152] (Fluorine-free anionic surfactant) In one embodiment, polymerization of fluoromonomers can be carried out in the presence of a fluorine-free anionic surfactant.

[0153] Fluorine-free anionic surfactants are non-fluorine hydrocarbon emulsifiers that do not contain fluorine atoms.Examples of fluorine-free anionic surfactants include JP 2013-542308, JP 2013-542309, JP 2013-542310, International Publication No. 2011 / 093403, International Publication No. 2012 / 111770, International Publication No. 2014 / 061803, International Publication No. 2019 / 065638, International Publication No. 2020 / 196779, International Publication No. 2008 / 060460, International Publication No. 2008 / 060461, International Publication No. 2008 / 070079, International Publication No. 2008 / 076385, International Publication No. 2012 / 064841, International Publication No. 2012 / 064485, International Publication No. 2022 / 072693, International Publication No. 2002 / 088206, International Publication No. 2002 / 088207, International Publication No. 2004 / 041878, International Publication No. 2008 / 033721, International Publication No. 2011 / 014715, International Publication No. 2011 / 162971, International Publication No. 2014 / 186648, UK Patent Application Publication No. 2517481, International Publication No. 2015 / 066166, International Publication No. 2015 / 116754, US Patent Application Publication No. 2004 / 0225053, International Publication No. 2006 / 135543, U.S. Patent Application Publication No. 2007 / 0032591, International Publication No. 2008 / 073685, International Publication No. 2008 / 073686, International Publication No. 2009 / 126504, International Publication No. 2013 / 016372, International Publication No. 2019 / 063445, International Publication No. 2020 / 101963, International Publication No. 2018 / 189090, International Publication No. 2019 / 002180, International Publication No. 2022 / 128190, International Publication No. 2020 / 12908 You may use the information described in publications such as No. 3, International Publication No. 2020 / 136679, International Publication No. 2021 / 070159, Indian Patent Application Publication No. 202111061280, International Publication No. 2024 / 115069, International Publication No. 2024 / 116206, International Publication No. 2023 / 247225, International Publication No. 2024 / 167876, International Publication No. 2024 / 161322, International Publication No. 2024 / 120805, Indian Patent Application Publication No. 202311011319, and International Publication No. 2024 / 231620.

[0154] Examples of fluorine-free anionic surfactants include carboxylic acids or their salts, sulfonic acids or their salts, and sulfuric acids or their salts. Fluorine-free anionic surfactants typically have a hydrophilic portion, such as a carboxylic acid, carboxylate salt, sulfonic acid, sulfonate, sulfuric acid, or sulfate salt, and a hydrophobic portion, such as a long-chain hydrocarbon portion, such as an alkyl group.

[0155] Examples of fluorine-free anionic surfactants include Resolution Performance Products' Versatic® 10 and BASF's Avanel S series (S-70, S-74, etc.).

[0156] As for fluorine-free anionic surfactants, R Ｚ - (L-M) ｘ (In the formula, R Ｚ However, it is a hydrophobic hydrocarbon moiety containing one or more carbon atoms. L may be the same or different in each occurrence and represents an ionic hydrophilic moiety, and M may be the same or different in each occurrence and represents one or more counterions of the ionic hydrophilic moiety. x represents the number of groups represented by -L-M bonded to Rz, and is an integer from 1 to 3. An anionic surfactant represented by ) is an example. Ｚ As for L, a hydrocarbon group having 1 to 100 carbon atoms, which may contain heteroatoms, is preferred. The heteroatoms may be inserted between carbon atoms or may be included in substituents bonded to carbon atoms. As for L, -ArSO ３ － , -SO ３ － , -SO ４ -, -PO ３ － or -COO － This is preferable. -ArSO ３ － It is an aryl sulfonate. M is H, a metal atom, NR ５Ｚ ４ Preferably, imidazolium which may have substituents, pyridinium which may have substituents, or phosphonium which may have substituents. ５ＺThe element is preferably H or an organic group (preferably an alkyl group having 1 to 3 carbon atoms). More specifically, the anionic surfactants described below are examples.

[0157] As for fluorine-free anionic surfactants, R Ｚ -LM (wherein, R Ｚ However, it is a monovalent organic group containing one or more carbon atoms. L is -ArSO ３ － , -SO ３ － , -SO ４ -, -PO ３ － or -COO － And M is H, a metal atom, NR ５Ｚ ４ , optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium, R ５Ｚ is H or an organic group, -ArSO ３ － Anionic surfactants, represented by aryl sulfonates, are also mentioned. Specifically, these include CH4 compounds such as lauric acid and lauryl sulfate (dodecyl sulfate). ３ - (CH ２ ) ｎ Examples include those expressed by -L-M (wherein n is an integer between 6 and 17, and L and M are the same as above). Ｚ However, it may be a linear or branched alkyl group having 1 or more carbon atoms, which may have substituents, or a cyclic alkyl group having 3 or more carbon atoms, which may have substituents. Ｚ If the alkyl group has three or more carbon atoms, it may contain a monovalent or divalent heterocycle, or it may form a ring. Ｚ However, it is preferable that it be an alkyl group having 3 to 18 carbon atoms. Ｚ However, a mixture of alkyl groups having 12 to 16 carbon atoms, where L-M is a sulfate, can also be used.

[0158] Other compounds with surfactant properties include R ６Ｚ (-L-M) ２ (In the formula, R ６ＺHowever, it is a monovalent organic group containing one or more carbon atoms. L is -ArSO ３ － , -SO ３ － , -SO ４ -, -PO ３ － or -COO － And M is H, a metal atom, NR ５Ｚ ４ , optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium, R ５Ｚ is H or an organic group, -ArSO ３ － Anionic surfactants represented by aryl sulfonates are also mentioned. ６Ｚ However, it may be a linear or branched alkylene group having 1 or more carbon atoms, which may have substituents, or a cyclic alkylene group having 3 or more carbon atoms, which may have substituents. ６Ｚ If the alkylene group has three or more carbon atoms, it may contain a monovalent or divalent heterocycle, or it may form a ring.

[0159] As for fluorine-free anionic surfactants, R ７Ｚ (-L-M) ３ (In the formula, R ７Ｚ However, it is a monovalent organic group containing one or more carbon atoms. L is -ArSO ３ － , -SO ３ － , -SO ４ -, -PO ３ － or -COO － And M is H, a metal atom, NR ５Ｚ ４ , optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium, R ５Ｚ is H or an organic group. -ArSO ３ － Anionic surfactants represented by aryl sulfonates are also mentioned. ７ＺHowever, it may be a linear or branched alkylidine group having 1 or more carbon atoms, which may have substituents, or a cyclic alkylidine group having 3 or more carbon atoms, which may have substituents. ７Ｚ If the alkylidine group has three or more carbon atoms, it may contain a monovalent or divalent heterocycle, or it may form a ring. ５ｚ H or an alkyl group is preferred, H or an alkyl group having 1 to 10 carbon atoms is more preferred, and H or an alkyl group having 1 to 4 carbon atoms is even more preferred.

[0160] In this disclosure, unless otherwise specified, “substituent” means a substituteable group. Examples of such “substituent” are aliphatic groups, aromatic groups, heterocyclic groups, acyl groups, acyloxy groups, acylamino groups, aliphatic oxy groups, aromatic oxy groups, heterocyclic oxy groups, aliphatic oxycarbonyl groups, aromatic oxycarbonyl groups, heterocyclic oxycarbonyl groups, carbamoyl groups, aliphatic sulfonyl groups, aromatic sulfonyl groups, heterocyclic sulfonyl groups, aliphatic sulfonyloxy groups, aromatic sulfonyloxy groups, heterocyclic sulfonyloxy groups, sulfamoyl groups, aliphatic sulfonamide groups, aromatic sulfonamide groups, heterocyclic sulfonamide groups, amino groups, aliphatic amino This includes a no 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 carboxyl 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 dialiphatic oxyphosphinyl group, or a diaromatic oxyphosphinyl group.

[0161] Siloxane hydrocarbon surfactants are another example of fluorine-free anionic surfactants. Siloxane hydrocarbon surfactants are also disclosed in U.S. Patent No. 6,841,616.

[0162] Examples of fluorine-free anionic surfactants include the sulfosuccinate surfactant Lankropol® K8300 from Akzo Nobel Surface Chemistry LLC. Examples of sulfosuccinate surfactants include sodium diisodecyl sulfosuccinate (Emulsogen® SB10 from Clariant) and sodium diisotridecyl sulfosuccinate (Policol® TR / LNA from Cesapinia Chemicals).

[0163] As a fluorine-free anionic surfactant, there is PolyFox® surfactant from Omnova Solutions, Inc. ＴＭ PF-156A, PolyFox ＴＭ Other examples include the PF-136A, etc.

[0164] Examples of fluorine-free anionic surfactants include those with the general formula (1): (In the formula, R １ ~R ５ represents H or a monovalent substituent, however, R １ and R ３ Of these, at least one is a general formula: -Y-R ６ The group indicated by, R ２ and R ５ Of these, at least one is a group represented by the general formula: -X-A, or the general formula: -Y-R ６ The group shown is represented by . Also, X is a divalent linking group or bond, which may be the same or different in each occurrence; A is -COOM, -SO, which may be the same or different in each occurrence. ３ M or -OSO ３ M (where M is H, metal atom, NR) ７ ４ , optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium, R ７ ( is H or an organic group); Y is the same or different in each occurrence, -S (=O) ２ -, -O-, -COO-, -OCO-, -CONR ８ - and -NR ８A divalent linking group selected from the group consisting of CO-, or a bond, R ８ is H or an organic group; R ６ R represents an alkyl group having one or more carbon atoms, which may contain at least one group selected from the group consisting of a carbonyl group, an ester group, an amide group, and a sulfonyl group between the carbon atoms, either identically or differently in each occurrence. １ ~R ５ Any two of these may bond with each other to form a ring. A surfactant represented by (hereinafter also referred to as surfactant (1)) is preferably exemplified.

[0165] Surfactants (1) will be explained.

[0166] In the formula, R １ ~R ５ represents H or a monovalent substituent, however, R １ and R ３ Of these, at least one is a general formula: -Y-R ６ The group indicated by, R ２ and R ５ Of these, at least one is a group represented by the general formula: -X-A, or the general formula: -Y-R ６ This represents the group indicated by R. １ ~R ５ Any two of these may combine with each other to form a ring.

[0167] R １ The substituents that the alkyl group may have are preferably halogen atoms, linear or branched alkyl groups having 1 to 10 carbon atoms, or cyclic alkyl groups having 3 to 10 carbon atoms, and hydroxyl groups, with methyl groups and ethyl groups being particularly preferred.

[0168] R １The alkyl group described above preferably does not contain a carbonyl group. The alkyl group may have 75% or less of the hydrogen atoms bonded to the carbon atom substituted with halogen atoms, 50% or less substituted with halogen atoms, or 25% or less substituted with halogen atoms, but it is preferable that it is a non-halogenated alkyl group that does not contain halogen atoms such as fluorine atoms or chlorine atoms. The alkyl group may preferably have no substituents whatsoever.

[0169] R １ Preferably, the alkyl group is a linear or branched alkyl group having 1 to 10 carbon atoms, which may have substituents, or a cyclic alkyl group having 3 to 10 carbon atoms, which may have substituents; more preferably, a linear or branched alkyl group having 1 to 10 carbon atoms that does not contain a carbonyl group, or a cyclic alkyl group having 3 to 10 carbon atoms that does not contain a carbonyl group; even more preferably, a linear or branched alkyl group having 1 to 10 carbon atoms without substituents; and even more preferably, a linear or branched alkyl group having 1 to 3 carbon atoms without substituents, and a methyl group (-CH ３ ) or ethyl group (-C ２ H ５ ) is particularly preferred, and a methyl group (-CH ３ ) is the most preferable.

[0170] As a monovalent substituent, the general formula is: -Y-R ６ A group represented by the formula: -X-A, -H, and C which may have a substituent. １－２０ Alkyl group, -NH ２ , - NHR ９ (R ９ (Organic group), -OH, -COOR ９ (R ９ (is an organic group) or -OR ９ (R ９ (An organic group is preferred.) The number of carbon atoms in the alkyl group is preferably 1 to 10.

[0171] R ９ C １－１０ alkyl group or C １－１０ The alkylcarbonyl group is preferred, C １－４ alkyl group or C １－４The alkylcarbonyl group is more preferable.

[0172] In the formula, X represents a divalent linking group or bond, which may be the same or different in each occurrence. ６ If X does not contain any carbonyl group, ester group, amide group, or sulfonyl group, it is preferable that X is a divalent linking group containing at least one selected from the group consisting of carbonyl group, ester group, amide group, and sulfonyl group.

[0173] X is -CO-, -S (=O) ２ -, -O-, -COO-, -OCO-, -S (=O) ２ -O-, -O-S (=O) ２ -, -CONR ８ - and -NR ８ A divalent linking group containing at least one bond selected from the group consisting of CO-, C １－１０ An alkylene group or bond is preferred. ８ represents H or an organic group.

[0174] R ８ Alkyl groups are preferred as the organic groups in R. ８ For example, H or C １－１０ The organic group is preferably H or C １－４ The organic group is more preferably H or C １－４ Alkyl alkyl groups are more preferred, and H is even more preferred.

[0175] In the formula, A is the same or different in each occurrence, -COOM, -SO ３ M or -OSO ３ M (where M is H, metal atom, NR) ７ ４ , optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium, R ７ is H or an organic group. There are four R ７ (These may be the same or different.) In general formula (1), one preferred embodiment is that A is -COOM.

[0176] R ７ Alkyl groups are preferred as the organic groups in R.７ For example, H or C １－１０ The organic group is preferably H or C １－４ The organic group is more preferably H or C １－４ Alkyl alkyl groups are even more preferred. Examples of the metal atoms include alkali metals (Group 1), alkaline earth metals (Group 2), etc., with Na, K, or Li being preferred.

[0177] M can be H, a metal atom, or NR ７ ４ Preferably, H, alkali metals (Group 1), alkaline earth metals (Group 2), or NR ７ ４ More preferably, H, Na, K, Li or NH ４ More preferably, Na, K or NH ４ More preferably, Na or NH ４ NH is particularly preferred. ４ Most preferable.

[0178] In the formula, Y is the same or different in each occurrence, -S (=O) ２ -, -O-, -COO-, -OCO-, -CONR ８ - and -NR ８ A divalent linking group selected from the group consisting of CO-, or a bond, R ８ represents H or an organic group.

[0179] Y is a combination of -O-, -COO-, -OCO-, and -CONR. ８ - and -NR ８ A divalent linking group selected from the group consisting of CO- is preferred, and a divalent linking group selected from the group consisting of -COO- and -OCO- is more preferred.

[0180] R ８ Alkyl groups are preferred as the organic groups in R. ８ For example, H or C １－１０ The organic group is preferably H or C １－４ The organic group is more preferably H or C １－４ Alkyl alkyl groups are more preferred, and H is even more preferred.

[0181] In the formula, R ６R represents an alkyl group having one or more carbon atoms, which may contain at least one selected from the group consisting of a carbonyl group, an ester group, an amide group, and a sulfonyl group between the carbon atoms, either identically or differently in each appearance. ６ The number of carbon atoms in the organic group is preferably 2 or more, preferably 20 or less, more preferably 2 to 20, and even more preferably 2 to 10.

[0182] R ６ The alkyl group, when it has two or more carbon atoms, may contain at least one or more groups selected from the group consisting of a carbonyl group, an ester group, an amide group, and a sulfonyl group between the carbon atoms, but the alkyl group does not contain any of these groups at either end. ６ The alkyl group may have 75% or less of the hydrogen atoms bonded to the carbon atom substituted with halogen atoms, 50% or less substituted with halogen atoms, or 25% or less substituted with halogen atoms, but it is preferable that it is a non-halogenated alkyl group that does not contain halogen atoms such as fluorine atoms or chlorine atoms.

[0183] R ６ For example, the general formula is: -R １０ -CO-R １１ The base shown by, general formula: -R １０ -COO-R １１ The base shown by, general formula: -R １１ The base shown by, general formula: -R １０ -NR ８ CO-R １１ The base shown by, or the general formula: -R １０ -CONR ８ -R １１ The base shown by (wherein R ８ R represents H or an organic group. １０ is an alkylene group, R １１ R is preferably an alkyl group which may have substituents. ６ For example, the general formula is: -R １０ -CO-R １１ The group indicated by is more preferable.

[0184] R ８ Alkyl groups are preferred as the organic groups in R.８ For example, H or C １－１０ The organic group is preferably H or C １－４ The organic group is more preferably H or C １－４ Alkyl alkyl groups are more preferred, and H is even more preferred.

[0185] R １０ The number of carbon atoms in the alkylene group is preferably 1 or more, more preferably 3 or more, preferably 20 or less, more preferably 12 or less, even more preferably 10 or less, and particularly preferably 8 or less. Also, R １０ The number of carbon atoms in the alkylene group is preferably 1 to 20, more preferably 1 to 10, and even more preferably 3 to 10.

[0186] R １１ The number of carbon atoms in the alkyl group may be 1 to 20, preferably 1 to 15, more preferably 1 to 12, even more preferably 1 to 10, even more preferably 1 to 8, especially preferably 1 to 6, even more preferably 1 to 3, particularly preferably 1 or 2, and most preferably 1. Also, the above R １１ The alkyl group is preferably composed only of primary, secondary, and tertiary carbon atoms, and is particularly preferably composed only of primary and secondary carbon atoms. That is, R １１ The preferred groups are methyl, ethyl, n-propyl, and isopropyl, with methyl being the most preferred.

[0187] In general formula (1), R ２ and R ５ In one preferred embodiment, at least one of these is a group represented by the general formula: -X-A, where A is -COOM.

[0188] As for fluorine-free anionic surfactants, see formula (1-0A): (In the formula, R １Ａ ~R ５Ａ is H, a monovalent hydrocarbon group which may contain an ester group between carbon atoms, or general formula: -X Ａ - The group is represented by A. However, R ２Ａ and R ５Ａ At least one of them is a general formula: -X Ａ - Represents the group indicated by A. X ＡIn each occurrence, the divalent hydrocarbon group, formula: -N(R) is the same or different. ６Ａ )-R ７Ａ - (R ６Ａ is H or -CH ２ COOM (M is as described below), R ７Ａ A is a group represented by a divalent hydrocarbon group, or a bond; A is the same or different in each occurrence, -COOM (M is H, a metal atom, NR ７ ４ , optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium, R ７ (is H or an organic group); R １Ａ ~R ５Ａ Any two of these may bond with each other to form a ring. Other examples include surfactants (1-0A) represented by ).

[0189] In general formula (1-0A), R １Ａ ~R ５Ａ In this, the monovalent hydrocarbon group, which may contain an ester group between carbon atoms, preferably has 1 to 50 carbon atoms, and more preferably 5 to 20 carbon atoms. １Ａ ~R ５Ａ Any two of these may bond to each other to form a ring. Among the monovalent hydrocarbon groups that may contain an ester group between the carbon atoms, alkyl groups are preferred. In the formula, X Ａ In this, the number of carbon atoms in the divalent hydrocarbon group is preferably 1 to 50, and more preferably 5 to 20. Examples of the above-mentioned divalent hydrocarbon group include alkylene groups and alkanediyl groups, with alkylene groups being preferred.

[0190] In general formula (1-0A), R ２Ａ and R ５Ａ Any one of the above general formulas: -X Ａ - Preferably the group is represented by A, R ２Ａ The above general formula is: -X Ａ It is more preferable that the group is represented by -A.

[0191] In the general formula (1-0A), a preferred embodiment is R ２Ａ However, the general formula is: -XＡ - The group represented by A, R １Ａ , R ３Ａ , R ４Ａ and R ５Ａ This is the mode in which H is present. In this case, X Ａ It is preferable that the bond is a C1-C5 alkylene group.

[0192] In the general formula (1-0A), a preferred embodiment is R ２Ａ However, the general formula is: -X Ａ - The group represented by A, R １Ａ and R ３Ａ ga-Y Ａ -R ６ It is a group represented by Y Ａ In each occurrence, they are identical or different, -COO-, -OCO-, or a combination, R ６ In each occurrence, R is the same or different alkyl group having one or more carbon atoms. ４Ａ and R ５Ａ It is preferable that it is H.

[0193] Examples of surfactants represented by the general formula (1-0A) include glutaric acid or its salts, adipic acid or its salts, pimelic acid or its salts, suberic acid or its salts, azelaic acid or its salts, sebacic acid or its salts, etc. Furthermore, the surfactant represented by the general formula (1-0A) may also be a two-chain, two-hydrophilic synthetic surfactant. Examples of gemini-type surfactants include GeminiSurf (Chukyo Oil & Fat Co., Ltd.), Gemsurf α142 (12 carbon atoms, lauryl group), Gemsurf α102 (10 carbon atoms), Gemsurf α182 (14 carbon atoms), etc.

[0194] In the general formula (1-0A), a preferred embodiment is R １Ａ ga-Y Ａ -R ６ It is a group represented by Y Ａ is a bonding hand, R ６ R is an alkyl group having 1 or more carbon atoms (preferably an alkylene group having 6 to 20 carbon atoms), ２Ａ , R ３Ａ , R ４Ａ and R ５Ａ H is XＡ However, the formula is: -N(R ６Ａ )-R ７Ａ - (R ６Ａ is H or -CH ２ COOM (M is as described above), R ７Ａ This embodiment is characterized by a group represented by an alkylene group (preferably a methylene group) having 1 to 5 carbon atoms. An example of a surfactant in this embodiment is lauryl hymine dicarboxylic acid.

[0195] Other examples of fluorine-free anionic surfactants include fluorine-free anionic surfactants having one or more carbonyl groups (excluding carbonyl groups in carboxyl groups). Furthermore, fluorine-free anionic surfactants having one or more carbonyl groups (excluding carbonyl groups in carboxyl groups) that have been subjected to radical treatment or oxidation treatment can also be used. The above radical treatment is any treatment that generates radicals in the fluorine-free anionic surfactant having one or more carbonyl groups (excluding carbonyl groups in carboxyl groups). For example, this treatment involves adding deionized water and a fluorine-free anionic surfactant to a reactor, sealing the reactor, purging the system with nitrogen, raising the temperature and pressure of the reactor, adding a polymerization initiator, stirring for a certain period of time, then depressurizing the reactor to atmospheric pressure and cooling it. The above oxidation treatment is a process in which an oxidizing agent is added to a fluorine-free anionic surfactant having one or more carbonyl groups (excluding carbonyl groups in carboxyl groups). Examples of oxidizing agents include oxygen, ozone, hydrogen peroxide, manganese(IV) oxide, potassium permanganate, potassium dichromate, nitric acid, and sulfur dioxide. To accelerate the radical treatment or oxidation treatment, the radical treatment or oxidation treatment may be carried out in an aqueous solution with adjusted pH. The pH of the aqueous solution for the radical treatment or oxidation treatment is preferably less than 7, and the pH of the aqueous solution can be adjusted using sulfuric acid, nitric acid, hydrochloric acid, etc.

[0196] As a fluorine-free anionic surfactant having one or more of the above carbonyl groups (excluding carbonyl groups in carboxyl groups), the formula is: R Ｘ -XＸ (In the formula, R Ｘ X is a fluorine-free organic group having 1 to 2000 carbon atoms and having one or more carbonyl groups (excluding carbonyl groups in carboxyl groups), and Ｘ is, -OSO ３ X Ｘ１ , -COOX Ｘ１ or -SO ３ X Ｘ１ (X Ｘ１ H, metal atoms, NR Ｘ１ ４ , imidazolium which may have substituents, pyridinium which may have substituents, or phosphonium which may have substituents, Ｘ１ R is H or an organic group, and may be the same or different. A surfactant represented by )) is preferred. Ｘ The carbon number is preferably 500 or less, more preferably 100 or less, even more preferably 50 or less, and even more preferably 30 or less. Ｘ１ An alkyl group is preferred as the organic group. Ｘ１ Preferably, the group is H or an organic group having 1 to 10 carbon atoms, more preferably H or an organic group having 1 to 4 carbon atoms, and even more preferably H or an alkyl group having 1 to 4 carbon atoms.

[0197] Examples of fluorine-free anionic surfactants include the following formula (a): (In the formula, R １ａ R is a linear or branched alkyl group having one or more carbon atoms, or a cyclic alkyl group having three or more carbon atoms, and the hydrogen atoms bonded to the carbon atoms may be substituted with a monovalent organic group containing a hydroxyl group or an ester bond. If there are two or more carbon atoms, it may contain a carbonyl group, and if there are three or more carbon atoms, it may contain a monovalent or divalent heterocycle or form a ring. ２ａ and R ３ａ These are independently single or divalent linking groups. １ａ , R ２ａ and R ３ａ X has a total of 6 or more carbon atoms. ａ H, metal atoms, NR ４ａ ４, imidazolium which may have substituents, pyridinium which may have substituents, or phosphonium which may have substituents, ４ａ R is either H or an organic group, and may be the same or different. １ａ , R ２ａ and R ３ａ Any two of these may bond with each other to form a ring. ) A surfactant represented by formula (a), and formula (b) below: (In the formula, R １ｂ R is a linear or branched alkyl group having 1 or more carbon atoms, which may have substituents, or a cyclic alkyl group having 3 or more carbon atoms, which may have substituents. If the number of carbon atoms is 3 or more, it may include a monovalent or divalent heterocycle or form a ring. ２ｂ and R ４ｂ R is independently either H or a substituent. ３ｂ is an alkylene group having 1 to 10 carbon atoms, which may have substituents. n is an integer of 1 or more. p and q are independently integers of 0 or more. X ｂ H, metal atoms, NR ５ｂ ４ , imidazolium which may have substituents, pyridinium which may have substituents, or phosphonium which may have substituents, ５ｂ R is either H or an organic group, and may be the same or different. １ｂ , R ２ｂ , R ３ｂ and R ４ｂ Any two of them may bond to each other to form a ring. L is a single bond, -CO ２ -B-*, -OCO-B-*, -CONR ６ｂ -B-*, -NR ６ｂ CO-B-*, or -CO- (however, -CO ２ -B-, -OCO-B-, -CONR ６ｂ -B-, -NR ６ CO-B- (excluding the carbonyl group contained therein), where B is a single bond or an alkylene group having 1 to 10 carbon atoms which may have substituents, and R ６ｂ is an alkyl group having 1 to 4 carbon atoms, which may have H or a substituent. * is -OSO in the formula. ３ Xｂ This refers to the side that binds to the surfactant (b), shown in the following formula (c): (In the formula, R １ｃ R is a linear or branched alkyl group having one or more carbon atoms, or a cyclic alkyl group having three or more carbon atoms, and the hydrogen atoms bonded to the carbon atoms may be substituted with a monovalent organic group containing a hydroxyl group or an ester bond. If there are two or more carbon atoms, it may contain a carbonyl group, and if there are three or more carbon atoms, it may contain a monovalent or divalent heterocycle or form a ring. ２ｃ and R ３ｃ These are independently single or divalent linking groups. １ｃ , R ２ｃ and R ３ｃ The total number of carbon atoms is 5 or more. ｃ is, -COOX ｃ or -SO ３ X ｃ (X ｃ H, metal atoms, NR ４ｃ ４ , imidazolium which may have substituents, pyridinium which may have substituents, or phosphonium which may have substituents, ４ｃ R is either H or an organic group, and may be the same or different. １ｃ , R ２ｃ and R ３ｃ Any two of these may bond with each other to form a ring.) A surfactant represented by formula (c), and the following formula (d): (In the formula, R １ｄ R is a linear or branched alkyl group having 1 or more carbon atoms, which may have substituents, or a cyclic alkyl group having 3 or more carbon atoms, which may have substituents. If the number of carbon atoms is 3 or more, it may include a monovalent or divalent heterocycle or form a ring. ２ｄ and R ４ｄ R is independently either H or a substituent. ３ｄ is an alkylene group having 1 to 10 carbon atoms, which may have substituents. n is an integer of 1 or more. p and q are independently integers of 0 or more. A ｄ is, -SO ３ X ｄ or -COOX ｄ (Xｄ H, metal atoms, NR ５ｄ ４ , imidazolium which may have substituents, pyridinium which may have substituents, or phosphonium which may have substituents, ５ｄ R is either H or an organic group, and may be the same or different. １ｄ , R ２ｄ , R ３ｄ and R ４ｄ Any two of them may bond to each other to form a ring. L is a single bond, -CO ２ -B-*, -OCO-B-*, -CONR ６ｄ -B-*, -NR ６ｄ CO-B-*, or -CO- (however, -CO ２ -B-, -OCO-B-, -CONR ６ｄ -B-, -NR ６ｄ CO-B- (excluding the carbonyl group contained therein), where B is a single bond or an alkylene group having 1 to 10 carbon atoms which may have substituents, and R ６ｄ is an alkyl group having 1 to 4 carbon atoms, which may have H or a substituent. * is A in the formula. ｄ This refers to the side that binds to (d). At least one selected from the group consisting of surfactants (d) represented by (d) is more preferable.

[0198] Surfactants (c) will be explained.

[0199] In formula (c), R １ｃ This is a linear or branched alkyl group having one or more carbon atoms, or a cyclic alkyl group having three or more carbon atoms. If the alkyl group has three or more carbon atoms, it may contain a carbonyl group (-C(=O)-) between two carbon atoms. Furthermore, if the alkyl group has two or more carbon atoms, it may contain the carbonyl group at the end of the alkyl group. That is, CH ３Acyl groups such as the acetyl group represented by -C(=O)- are also included in the alkyl groups mentioned above. Furthermore, if the alkyl group has three or more carbon atoms, it may include a monovalent or divalent heterocycle, or it may form a ring. As the heterocycle, an unsaturated heterocycle is preferred, and an oxygen-containing unsaturated heterocycle is more preferred, such as a furan ring. R １ｃ In this configuration, a divalent heterocycle may be inserted between two carbon atoms, or a divalent heterocycle may be located at the terminal and bonded to -C(=O)-, or a monovalent heterocycle may be located at the terminal of the alkyl group.

[0200] In this disclosure, the "number of carbon atoms" of the alkyl group includes the number of carbon atoms constituting the carbonyl group and the number of carbon atoms constituting the heterocycle. For example, CH ３ -C(=O)-CH ２ The group indicated by - has 3 carbon atoms, CH ３ -C (=O) -C ２ H ４ -C (=O) -C ２ H ４ The group indicated by - has 7 carbon atoms, CH ３ The group represented by -C(=O)- has two carbon atoms.

[0201] The alkyl group described above may have hydrogen atoms bonded to carbon atoms substituted with functional groups, for example, with a hydroxyl group (-OH) or a monovalent organic group containing an ester bond, but it is preferable that it is not substituted with any functional group. The monovalent organic group containing an ester bond described above has the formula: -O-C(=O)-R １０１ｃ (In the formula, R １０１ｃ Examples of groups are those represented by alkyl groups. The alkyl group may have 75% or less of the hydrogen atoms bonded to the carbon atom substituted with halogen atoms, 50% or less substituted with halogen atoms, or 25% or less substituted with halogen atoms, but it is preferable that it is a non-halogenated alkyl group that does not contain halogen atoms such as fluorine atoms or chlorine atoms.

[0202] In formula (c), R ２ｃ and R ３ｃThese are independently single or divalent linking groups. ２ｃ and R ３ｃ Preferably, each of these is independently a single bond, a linear or branched alkylene group having 1 or more carbon atoms, or a cyclic alkylene group having 3 or more carbon atoms. ２ｃ and R ３ｃ The alkylene group constituting the above preferably does not contain a carbonyl group.

[0203] The alkylene group described above may have hydrogen atoms bonded to carbon atoms substituted with functional groups, for example, with a hydroxyl group (-OH) or a monovalent organic group containing an ester bond, but it is preferable that it is not substituted with any functional group. The monovalent organic group containing the ester bond described above has the formula: -O-C(=O)-R １０２ｃ (In the formula, R １０２ｃ Examples of groups are those represented by alkyl groups. The alkylene group may have 75% or less of the hydrogen atoms bonded to the carbon atom substituted with halogen atoms, 50% or less substituted with halogen atoms, or 25% or less substituted with halogen atoms, but it is preferable that it is a non-halogenated alkylene group that does not contain halogen atoms such as fluorine atoms or chlorine atoms.

[0204] R １ｃ , R ２ｃ and R ３ｃ The total number of carbon atoms is 5 or more. Preferably, the total number of carbon atoms is 7 or more, more preferably 9 or more, preferably 20 or less, more preferably 18 or less, and even more preferably 15 or less. １ｃ , R ２ｃ and R ３ｃ Any two of them may be joined together to form a ring.

[0205] In formula (c), in the formula, A ｃ is, -COOX ｃ or -SO ３ X ｃ (X ｃ H, metal atoms, NR ４ｃ ４, imidazolium which may have substituents, pyridinium which may have substituents, or phosphonium which may have substituents, ４ｃ (This is H or an organic group, and may be the same or different.) A ｃ As for, -COOX ｃ This is preferable. ４ｃ Alkyl groups are preferred as the organic groups in R. ４ｃ Preferably, the metal atom is H or an organic group having 1 to 10 carbon atoms, more preferably H or an organic group having 1 to 4 carbon atoms, and even more preferably H or an alkyl group having 1 to 4 carbon atoms. Examples of the metal atoms include monovalent and divalent metal atoms, such as alkali metals (Group 1) and alkaline earth metals (Group 2), with Na, K, or Li being preferred. ｃ Examples include H, alkali metals (Group 1), alkaline earth metals (Group 2), or NR ４ｃ ４ Preferably, H, Na, K, Li or NH ４ More preferable and more easily soluble in water, Na, K, or NH ４ More preferably, Na or NH ４ This is particularly preferable and easy to remove, NH ４ This is the most preferable. X ｃ NH ４ As a result, the surfactant exhibits excellent solubility in aqueous media, and metal components are less likely to remain in the polymer or the final product.

[0206] Let's explain surfactants (d).

[0207] In formula (d), R １ｄ This is a linear or branched alkyl group having one or more carbon atoms, which may have substituents, or a cyclic alkyl group having three or more carbon atoms, which may have substituents. If the alkyl group has three or more carbon atoms, it may include a monovalent or divalent heterocycle, or it may form a ring. As the heterocycle, an unsaturated heterocycle is preferred, and an oxygen-containing unsaturated heterocycle is more preferred, such as a furan ring. １ｄIn this configuration, a divalent heterocycle may be inserted between two carbon atoms, or a divalent heterocycle may be located at the terminal and bonded to -C(=O)-, or a monovalent heterocycle may be located at the terminal of the alkyl group.

[0208] In this disclosure, the "number of carbon atoms" of the alkyl group above includes the number of carbon atoms constituting the heterocycle above.

[0209] R １ｄ The substituents that the alkyl group may have are preferably halogen atoms, linear or branched alkyl groups having 1 to 10 carbon atoms, or cyclic alkyl groups having 3 to 10 carbon atoms, and hydroxyl groups, with methyl groups and ethyl groups being particularly preferred.

[0210] R １ｄ The alkyl group described above preferably does not contain a carbonyl group. The alkyl group may have 75% or less of the hydrogen atoms bonded to the carbon atom substituted with halogen atoms, 50% or less substituted with halogen atoms, or 25% or less substituted with halogen atoms, but it is preferable that it is a non-halogenated alkyl group that does not contain halogen atoms such as fluorine atoms or chlorine atoms. The alkyl group may preferably have no substituents whatsoever.

[0211] R １ｄ Preferably, the alkyl group is a linear or branched alkyl group having 1 to 10 carbon atoms, which may have substituents, or a cyclic alkyl group having 3 to 10 carbon atoms, which may have substituents; more preferably, a linear or branched alkyl group having 1 to 10 carbon atoms that does not contain a carbonyl group, or a cyclic alkyl group having 3 to 10 carbon atoms that does not contain a carbonyl group; even more preferably, a linear or branched alkyl group having 1 to 10 carbon atoms without substituents; and even more preferably, a linear or branched alkyl group having 1 to 3 carbon atoms without substituents, and a methyl group (-CH ３ ) or ethyl group (-C ２ H ５ ) is particularly preferred, and a methyl group (-CH ３ ) is the most preferable.

[0212] In formula (d), R ２ｄ and R４ｄ These are independently H or substituents. Multiple R ２ｄ and R ４ｄ These may be the same or different.

[0213] R ２ｄ and R ４ｄ The substituents mentioned above are preferably halogen atoms, linear or branched alkyl groups having 1 to 10 carbon atoms, or cyclic alkyl groups having 3 to 10 carbon atoms, and hydroxyl groups, with methyl groups and ethyl groups being particularly preferred.

[0214] R ２ｄ and R ４ｄ The alkyl group described above preferably does not contain a carbonyl group. The alkyl group may have 75% or less of the hydrogen atoms bonded to the carbon atom substituted with halogen atoms, 50% or less substituted with halogen atoms, or 25% or less substituted with halogen atoms, but it is preferable that it is a non-halogenated alkyl group that does not contain halogen atoms such as fluorine atoms or chlorine atoms. The alkyl group may preferably have no substituents whatsoever.

[0215] R ２ｄ and R ４ｄ The alkyl group described above is preferably a linear or branched alkyl group having 1 to 10 carbon atoms that does not contain a carbonyl group, or a cyclic alkyl group having 3 to 10 carbon atoms that does not contain a carbonyl group, more preferably a linear or branched alkyl group having 1 to 10 carbon atoms that does not contain a carbonyl group, and even more preferably a linear or branched alkyl group having 1 to 3 carbon atoms that does not have substituents, and a methyl group (-CH ３ ) or ethyl group (-C ２ H ５ ) is particularly preferable.

[0216] R ２ｄ and R ４ｄ Preferably, the alkyl group is a linear or branched alkyl group having 1 to 10 carbon atoms that does not contain H or a carbonyl group, more preferably a linear or branched alkyl group having 1 to 3 carbon atoms that does not contain H or a substituent, and H, methyl group (-CH ３ ) or ethyl group (-C ２ H５ ) is even more preferable, and H is particularly preferable.

[0217] In formula (d), R ３ｄ R is an alkylene group having 1 to 10 carbon atoms, which may have substituents. ３ｄ If there are multiple instances of this, they may be identical or different.

[0218] The alkylene group described above preferably does not contain a carbonyl group. The alkylene group may have 75% or less of the hydrogen atoms bonded to the carbon atom substituted with halogen atoms, 50% or less substituted with halogen atoms, or 25% or less substituted with halogen atoms, but it is preferable that it is a non-halogenated alkyl group that does not contain halogen atoms such as fluorine atoms or chlorine atoms. The alkylene group described above preferably does not have any substituents.

[0219] The alkylene group is preferably a linear or branched alkylene group having 1 to 10 carbon atoms, which may have substituents, or a cyclic alkylene group having 3 to 10 carbon atoms, which may have substituents; preferably a linear or branched alkylene group having 1 to 10 carbon atoms that does not contain a carbonyl group; more preferably a linear or branched alkylene group having 1 to 10 carbon atoms that does not contain a substituent; and more preferably a methylene group (-CH ２ -), ethylene group (-C ２ H ４ -), isopropylene group (-CH(CH ３ )CH ２ -) or propylene group (-C) ３ H ６ -) is even more preferable.

[0220] R １ｄ , R ２ｄ , R ３ｄ and R ４ｄ Any two of them may be joined together to form a ring.

[0221] In formula (d), n is an integer greater than or equal to 1. n is preferably an integer between 1 and 40, more preferably between 1 and 30, and even more preferably between 5 and 25.

[0222] In formula (d), p and q are independently integers of 0 or greater. p is preferably an integer between 0 and 10, and more preferably 0 or 1. q is preferably an integer between 0 and 10, and more preferably an integer between 0 and 5.

[0223] It is preferable that n, p, and q are integers whose sum is 6 or greater. It is more preferable that the sum of n, p, and q is an integer of 8 or greater. It is also preferable that the sum of n, p, and q is an integer of 60 or less, more preferably an integer of 50 or less, and even more preferably an integer of 40 or less.

[0224] In formula (d), A ｄ is, -SO ３ X ｄ or -COOX ｄ (X ｄ H, metal atoms, NR ５ｄ ４ , imidazolium which may have substituents, pyridinium which may have substituents, or phosphonium which may have substituents, ５ｄ (This is H or an organic group, and may be the same or different.) A ｄ As for, -COOX ｄ This is preferable. ５ｄ Alkyl groups are preferred as the organic groups in R. ５ｄ Preferably, the metal atom is H or an organic group having 1 to 10 carbon atoms, more preferably H or an organic group having 1 to 4 carbon atoms, and even more preferably H or an alkyl group having 1 to 4 carbon atoms. Examples of the metal atoms include monovalent and divalent metal atoms, such as alkali metals (Group 1) and alkaline earth metals (Group 2), with Na, K, or Li being preferred. ｄ is a metal atom or NR ５ｄ ４ (R ５ｄ (As stated above) may be X ｄ Examples include H, alkali metals (Group 1), alkaline earth metals (Group 2), or NR ５ｄ ４ Preferably, H, Na, K, Li or NH ４ More preferable and more easily soluble in water, Na, K, or NH ４More preferably, Na or NH ４ This is particularly preferable and easy to remove, NH ４ This is the most preferable. X ｄ NH ４ As a result, the surfactant exhibits excellent solubility in aqueous media, and metal components are less likely to remain in the polymer or the final product.

[0225] In equation (d), L is a single bond, -CO ２ -B-*, -OCO-B-*, -CONR ６ｄ -B-*, -NR ６ｄ CO-B-*, or -CO- (however, -CO ２ -B-, -OCO-B-, -CONR ６ｄ -B-, -NR ６ｄ (Excluding the carbonyl group contained in CO-B-), where B is a single bond or an alkylene group having 1 to 10 carbon atoms which may have substituents, and R ６ｄ is an alkyl group having 1 to 4 carbon atoms, which may have H or substituents. The alkylene group is more preferably having 1 to 5 carbon atoms. Also, the above R ６ｄ It is more preferably H or a methyl group. * is A in the formula ｄ This refers to the side that connects to it.

[0226] L is preferably a single bond.

[0227] As a fluorine-free anionic surfactant, see formula I: R-(XZ) ｎ (I) (wherein R is a hydrophobic hydrocarbon moiety containing one or more saturated or unsaturated, acyclic or cyclic aliphatic groups. CH in one or more aliphatic groups) ３ ,CH ２ and CH for the total of CH groups ３ The total percentage of the groups is at least about 70%, and the hydrophobic portion does not contain siloxane units. Each X may be the same or different and represents an ionic hydrophilic portion. Each Z may be the same or different and represents one or more counterions of the ionic hydrophilic portion. n is 1 to 3. Compound I, shown in (), is also an example.

[0228] Compound I exhibits low reactivity with polymerization initiators and / or growing fluoropolymer radicals in the polymerization of fluoromonomers.

[0229] Compound I is given by the following formula: (In the formula, Y ＋ It is preferable that the substitution moiety is represented by ( ), which is hydrogen, ammonium, quaternary ammonium, nitrogen heterocycle, alkali metal, or alkaline earth element.

[0230] Compound I is given by the following formula II: (In the formula, R ２’ and R ２’’ R is a saturated or unsaturated, acyclic or cyclic aliphatic group having 4 to 16 carbon atoms, and is either the same or different. ２’ and R ２’’ CH in the base ３ ,CH ２ and CH for the total of CH groups ３ The percentage of the sum of the bases is at least about 70%, or R ２’ and R ２’’ These can bond together to form saturated or unsaturated aliphatic rings that may contain ether or ester bonds. However, the CH in the ring ３ ,CH ２ and CH for the total of CH groups ３ The percentage of the sum of the bases is at least about 70%. １ These are hydrogen, methoxy, ethoxy, or phenoxy. ＋ It is preferably compound II represented by ( ).

[0231] For compound II, the following compounds are preferred, for example. Y in the above formula ＋ This may be hydrogen, ammonium, or an alkali metal.

[0232] Compound I is given by the following formula III: (In the formula, R ３ , R ４’ , and R ４’’R is a saturated or unsaturated, acyclic or cyclic aliphatic group having hydrogen or 4 to 16 carbon atoms, and is either the same or different. ３ , R ４’ , and R ４’’ CH at the base ３ ,CH ２ And with respect to the total number of CH groups ３ The total percentage of is at least about 70%. However, R ３ , R ４’ , and R ４’’ At least one of them is not hydrogen, R ４’ and R ４’’ If R is hydrogen, ３ It is not hydrogen, but R ３ If R is hydrogen, ４’ and R ４’’ It is not hydrogen. Y ＋ It is also preferable that it is compound III represented by ( ).

[0233] For example, the following compounds are preferred as compound III. Y in the above formula ＋ This may be hydrogen, ammonium, or an alkali metal.

[0234] In the manufacturing method of this disclosure, two or more fluorine-free anionic surfactants may be used simultaneously.

[0235] Furthermore, examples of fluorine-free anionic surfactants include the surfactant (1) described above, a fluorine-free anionic surfactant having one or more carbonyl groups (excluding carbonyl groups in carboxyl groups), or a specific fluorine-free anionic surfactant obtained by radical treatment or oxidation treatment of a fluorine-free anionic surfactant having one or more carbonyl groups (excluding carbonyl groups in carboxyl groups). The specific fluorine-free anionic surfactant is preferably a fluorine-free anionic surfactant obtained by radical treatment or oxidation treatment of a fluorine-free anionic surfactant having one or more carbonyl groups (excluding carbonyl groups in carboxyl groups), or a fluorine-free anionic surfactant obtained by radical treatment or oxidation treatment of a fluorine-free anionic surfactant having one or more carbonyl groups (excluding carbonyl groups in carboxyl groups). By using specific fluorine-free anionic surfactants that have undergone radical treatment or oxidation treatment, primary particles with a small average primary particle size and aspect ratio can be easily obtained. This allows for smooth polymerization of monomers in an aqueous medium, and facilitates the production of polymers.

[0236] Radical treatment refers to any treatment in which a radical is applied to a fluorine-free anionic surfactant. For example, this treatment involves adding deionized water and a fluorine-free anionic surfactant to a reactor, sealing the reactor, purging the system with nitrogen, raising the temperature and pressure of the reactor, adding a polymerization initiator, stirring for a certain period of time, then depressurizing the reactor to atmospheric pressure and cooling it. The oxidation treatment refers to a treatment in which an oxidizing agent is applied to a fluorine-free anionic surfactant. Examples of oxidizing agents include oxygen, ozone, hydrogen peroxide, manganese(IV) oxide, potassium permanganate, potassium dichromate, nitric acid, and sulfur dioxide.

[0237] The above-mentioned specific fluorine-free anionic surfactant is preferably at least one selected from the group consisting of the surfactant (1) represented by the general formula (1), the surfactant (a) represented by the formula (a), the surfactant (b) represented by the formula (b), the surfactant (c) represented by the formula (c), the surfactant (d) represented by the formula (d), and surfactants obtained by radical treatment or oxidation treatment of these surfactants (a) to (d). More preferably, at least one selected from the group consisting of the surfactant (a) represented by the formula (a), the surfactant (b) represented by the formula (b), the surfactant (c) represented by the formula (c), the surfactant (d) represented by the formula (d), and surfactants obtained by radical treatment or oxidation treatment of these surfactants (a) to (d).

[0238] In the manufacturing method of this disclosure, the fluorine-free anionic surfactant used is preferably a carboxylic acid-type fluorine-free anionic surfactant. Carboxylic acid-type fluorine-free anionic surfactants tend to have a shorter coagulation completion time compared to sulfate ester-based surfactants. However, according to the manufacturing method of this disclosure, even when a carboxylic acid-type hydrocarbon surfactant is used, an aqueous dispersion with a long coagulation completion time can be produced. In other words, the manufacturing method of this disclosure is particularly suitable when the fluorine-free anionic surfactant is a carboxylic acid-type fluorine-free anionic surfactant. The carboxylic acid-type fluorine-free anionic surfactant is usually an anionic hydrocarbon surfactant having a hydrophilic portion of a carboxylate salt and a hydrophobic portion which is a long-chain hydrocarbon portion such as an alkyl group. Specifically, it is not limited to those having a carboxyl group (-COOH) or a group in which the hydrogen atoms of the carboxyl group are substituted with inorganic cations (e.g., metal atoms, ammonium, etc.). For example, from the above-mentioned fluorine-free anionic surfactants, a fluorine-free anionic surfactant having a carboxyl group or a group in which the hydrogen atoms of the carboxyl group are substituted with inorganic cations can be used.

[0239] The fluorine-free anionic surfactant may be an aliphatic carboxylic acid-type fluorine-free anionic surfactant, or a carboxylic acid-type fluorine-free anionic surfactant other than an aliphatic type. In this disclosure, "aliphatic carboxylic acid-type fluorine-free anionic surfactant" means a carboxylic acid-type fluorine-free anionic surfactant that does not contain a carbonyl group (excluding carbonyl groups in carboxyl groups and ester groups). The ester group refers to a group represented by -COO- or -OCO-.

[0240] As a carboxylic acid-type fluorine-free anionic surfactant, for example, a fluorine-free anionic surfactant having a carboxyl group or a group in which the hydrogen atoms of a carboxyl group are substituted with an inorganic cation can be used from among the fluorine-free anionic surfactants described above.

[0241] As a carboxylic acid-type fluorine-free anionic surfactant, surfactant (1), the above formula: R ６ｚ (-L-M) ２ Anionic surfactants represented by the above formula: R ７ｚ (-L-M) ３ It is preferable that the anionic surfactant represented by is at least one selected from the group consisting of those having a carboxyl group (-COOH) or a group in which the hydrogen atom of the carboxyl group is substituted with an inorganic cation (e.g., a metal atom, ammonium, etc.), surfactants (1-0A), and surfactants that have been subjected to radical treatment or oxidation treatment. The above carboxylic acid-type fluorine-free anionic surfactant may be used individually or as a mixture of two or more.

[0242] As carboxylic acid-type fluorine-free anionic surfactants, at least one selected from the group consisting of lauric acid, capric acid, myristic acid, pentadecyl acid, palmitic acid, and salts thereof, and compounds obtained by radical treatment or oxidation treatment of these compounds is particularly preferred; at least one selected from the group consisting of lauric acid and salts thereof, and compounds obtained by radical treatment or oxidation treatment of these compounds is more preferred; at least one selected from the group consisting of salts of lauric acid and compounds obtained by radical treatment or oxidation treatment thereof is even more preferred; and at least one selected from the group consisting of sodium laurate and compounds obtained by radical treatment or oxidation treatment thereof is even more preferred. As for the salts, the hydrogen of the carboxyl group is a metal atom of formula M described above, NR １０１ ４ Examples include, but are not limited to, imidazolium which may have substituents, pyridinium which may have substituents, or phosphonium which may have substituents.

[0243] The amount of fluorine-free anionic surfactant used is preferably 0.0001 to 10% by mass, more preferably 0.001% by mass or more, and more preferably 1% by mass or less, relative to the aqueous medium.

[0244] (Fluorine-containing surfactant) In one embodiment, polymerization of fluoromonomers can be carried out in the presence of a fluorine-containing surfactant.

[0245] The fluorine-containing surfactant is not particularly limited as long as it contains at least one fluorine atom, and conventionally known fluorine-containing surfactants can be used.

[0246] Examples of fluorine-containing surfactants include fluorine-containing anionic surfactants. A fluorine-containing anionic surfactant may be, for example, a surfactant containing fluorine atoms with a total carbon number of 20 or less in the part excluding the anionic group.

[0247] The above-mentioned fluorine-containing surfactant may also be a surfactant containing fluorine with a molecular weight of 1000 or less in the anionic portion. The above-mentioned "anionic portion" refers to the portion of the above-mentioned fluorine-containing surfactant excluding the cation. For example, F(CF) represented by formula (I) described later. ２ ) ｎ１ In the case of COOM, "F(CF) ２ ) ｎ１ This is the "COO" part.

[0248] Specifically, the above-mentioned fluorine-containing surfactants include U.S. Patent Publication No. 2007 / 0015864, U.S. Patent Publication No. 2007 / 0015865, U.S. Patent Publication No. 2007 / 0015866, U.S. Patent Publication No. 2007 / 0276103, U.S. Patent Publication No. 2007 / 0117914, U.S. Patent Publication No. 2007 / 142541, U.S. Patent Publication No. 2008 / 0015319, U.S. Patent No. 3250808, U.S. Patent No. 3271341, and JP 20 Examples include those described in Japanese Patent Publication No. 03-119204, International Publication No. 2005 / 042593, International Publication No. 2008 / 060461, International Publication No. 2007 / 046377, Japanese Patent Publication No. 2007-119526, International Publication No. 2007 / 046482, International Publication No. 2007 / 046345, U.S. Patent Application Publication No. 2014 / 0228531, International Publication No. 2013 / 189824, International Publication No. 2013 / 189826, Chinese Patent Application Publication No. 102504063, and Chinese Patent Application Publication No. 110845653.

[0249] The above fluorine-containing anionic surfactant is the following general formula (N ０ ): X ｎ０ -Rf ｎ０ -Y ０ (N ０ ) (wherein, X ｎ０ These are H, Cl, and F. ｎ０ This is an alkylene group having 3 to 20 carbon atoms, being linear, branched, or cyclic, in which some or all of the hydrogen atoms are substituted with fluorine. The alkylene group may contain one or more ether bonds, and some of the hydrogen atoms may be substituted with chlorine.０ The group is an anionic group. Examples of compounds represented by ) are Y. ０ The anionic groups are -COOM and -SO ２ M, or -SO ３ It may be M, -COOM, or -SO ３ It can be M. M is H, a metal atom, NR ７ ４ , imidazolium which may have substituents, pyridinium which may have substituents, or phosphonium which may have substituents, ７ This is either H or an organic group. Examples of the metal atoms include alkali metals (Group 1), alkaline earth metals (Group 2), etc., such as Na, K, or Li. R ７ For example, H or C １－１０ The organic group may be H or C １－４ The organic group may be H or C １－４ It may be an alkyl group. M is H, a metal atom or NR ７ ４ It may be H, alkali metals (Group 1), alkaline earth metals (Group 2), or NR ７ ４ It may be H, Na, K, Li or NH ４ That is acceptable. (See Rf above) ｎ０ It is acceptable if 50% or more of the H is replaced with fluorine.

[0250] The above general formula (N ０ Compounds represented by the following general formula (N １ ): X ｎ０ - (CF ２ ) ｍ１ -Y ０ (N １ ) (wherein, X ｎ０ These are H, Cl, and F, and m1 is an integer from 3 to 15, Y ０ This is defined above.) Compounds represented by the following general formula (N ２ ): Rf ｎ１ -O-(CF(CF ３ ) CF ２ O) ｍ２ CFX ｎ１ -Y０ (N ２ ) (wherein, Rf ｎ１ m2 is a perfluoroalkyl group having 1 to 5 carbon atoms, m2 is an integer from 0 to 3, and X ｎ１ is F or CF ３ Y ０ This is defined above.) Compounds represented by the following general formula (N ３ ): Rf ｎ２ (CH ２ ) ｍ３ - (Rf ｎ３ ) ｑ -Y ０ (N ３ ) (wherein, Rf ｎ２ m3 is a partially or fully fluorinated alkyl group that may contain ether bonds and / or chlorine atoms with 1 to 13 carbon atoms, m3 is an integer from 1 to 3, and Rf ｎ３ is a linear or branched perfluoroalkylene group having 1 to 3 carbon atoms, where q is 0 or 1, and Y ０ This is defined above.) Compounds 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 Y is a linear or branched portion that may contain ether bonds with 1 to 12 carbon atoms, or a fully fluorinated alkyl group. ｎ１ and Y ｎ２ is the same or different, H or F, p is 0 or 1, Y ０ This refers to the compounds represented by the above definition, and the general formula (N ５ ): (In the formula, X ｎ２ , X ｎ３ and X ｎ４ Rf is a linear or branched portion that may contain H, F, or an ether bond having 1 to 6 carbon atoms, or a fully fluorinated alkyl group, and may be the same or different. ｎ５is a linear or branched moiety or a fully fluorinated alkylene group that may contain ether bonds with 1 to 3 carbon atoms, L is a linking group, and Y ０ This is as defined above. However, X ｎ２ , X ｎ３ , X ｎ４ and Rf ｎ５ The total number of carbon atoms is 18 or less. Examples of compounds represented by ) include those represented by ).

[0251] The above general formula (N ０ More specifically, examples of compounds represented by the formula (I) include perfluorocarboxylic acid (I) represented by the following general formula (I), ω-H perfluorocarboxylic acid (II) represented by the following general formula (II), perfluoroether carboxylic acid (III) represented by the following general formula (III), perfluoroalkylalkylene carboxylic acid (IV) represented by the following general formula (IV), perfluoroalkoxyfluorocarboxylic acid (V) represented by the following general formula (V), perfluoroalkyl sulfonic acid (VI) represented by the following general formula (VII), ω-H perfluorosulfonic acid (VII) represented by the following general formula (VII), perfluoroalkylalkylene sulfonic acid (VIII) represented by the following general formula (VII), alkylalkylene carboxylic acid (IX) represented by the following general formula (IX), fluorocarboxylic acid (X) represented by the following general formula (X), alkoxyfluorosulfonic acid (XI) represented by the following general formula (XI), compound (XII) represented by the following general formula (XII), and compound (XIII) represented by the following general formula (XIII).

[0252] The above perfluorocarboxylic acid (I) is given by the following general formula (I): F(CF) ２ ) ｎ１ COOM (I) (wherein n1 is an integer from 3 to 14, and M is H, a metal atom, NR) ７ ４ , imidazolium which may have substituents, pyridinium which may have substituents, or phosphonium which may have substituents, ７ (where is H or an organic group.)

[0253] The above ω-H perfluorocarboxylic acid (II) is represented by the following general formula (II): H(CF ２ ) ｎ２ COOM (II) (where n2 is an integer from 4 to 15, and M is as defined above).

[0254] 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) (where Rf １ is a perfluoroalkyl group having 1 to 5 carbon atoms, n3 is an integer from 0 to 3, and M is as defined above).

[0255] The above perfluoroalkyl alkylene carboxylic acid (IV) is represented by the following general formula (IV): Rf ２ (CH ２ ) ｎ４ Rf ３ COOM (IV) (where Rf ２ is a perfluoroalkyl group having 1 to 5 carbon atoms, Rf ３ is a linear or branched perfluoroalkylene group having 1 to 3 carbon atoms, n4 is an integer from 1 to 3, and M is as defined above).

[0256] The above alkoxyfluorocarboxylic acid (V) is represented by the following general formula (V): Rf ４ -O-CY １ Y ２ CF ２ -COOM (V) (where Rf ４ is a linear or branched or fully fluorinated alkyl group which may contain an ether bond and / or a chlorine atom having 1 to 12 carbon atoms, Y １ and Y ２ are the same or different and are H or F, and M is as defined above).

[0257] The above perfluoroalkylsulfonic acid (VI) is represented by the following general formula (VI): F(CF ２ ) ｎ５ SO ３ M (VI) (where n5 is an integer from 3 to 14, and M is as defined above).

[0258] The above ω-H perfluorosulfonic acid (VII) is represented by the following general formula (VII): H(CF ２ ) ｎ６ SO ３ M (VII) (where n6 is an integer from 4 to 14, and M is as defined above).

[0259] The above perfluoroalkylalkylene sulfonic acid (VIII) is represented by the following general formula (VIII): Rf ５ (CH ２ ) ｎ７ SO ３ M (VIII) (where Rf ５ is a perfluoroalkyl group having 1 to 13 carbon atoms, n7 is an integer from 1 to 3, and M is as defined above).

[0260] The above alkylalkylene carboxylic acid (IX) is represented by the following general formula (IX): Rf ６ (CH ２ ) ｎ８ COOM (IX) (where Rf ６ is a linear or branched or fully fluorinated alkyl group which may contain an ether bond having 1 to 13 carbon atoms, n8 is an integer from 1 to 3, and M is as defined above).

[0261] The above fluorocarboxylic acid (X) is represented by the following general formula (X): Rf ７ -O-Rf ８ -O-CF ２ -COOM (X) (where 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(where M is a linear or branched portion having 1 to 6 carbon atoms or a fully fluorinated alkyl group, and M is as defined above.)

[0262] The above alkoxyfluorosulfonic acid (XI) is given by the following general formula (XI) Rf ９ -O-CY １ Y ２ CF ２ -SO ３ M (XI) (wherein, Rf ９ Y is a partially or fully fluorinated alkyl group that may contain ether bonds between 1 to 12 carbon atoms, and may contain chlorine. １ and Y ２ (These are the same or different H or F, and M is as defined above.)

[0263] The above compound (XII) has the following general formula (XII): (In the formula, X １ , X ２ and X ３ Rf may be the same or different linear or branched portion containing H, F and ether bonds having 1 to 6 carbon atoms, or a fully fluorinated alkyl group. １０ L is a perfluoroalkylene group having 1 to 3 carbon atoms, L is a linking group, and Y ０ It is an anionic group. ) It is represented by Y ０ -COOM, -SO ２ M, or -SO ３ It may be M, -SO ３ M may be COOM (wherein M is as defined above). Examples of L include a single bond, a moiety that may contain an ether bond having 1 to 10 carbon atoms, or a fully fluorinated alkylene group.

[0264] The above compound (XIII) is given by the following general formula (XIII): Rf １１ -O-(CF ２ CF (CF ３ )O) ｎ９ (CF ２ O) ｎ１０ CF２ COOM (XIII) (wherein, Rf １１ is a fluoroalkyl group having 1 to 5 carbon atoms and containing chlorine, n9 is an integer from 0 to 3, n10 is an integer from 0 to 3, and M is as defined above. The compound (XIII) is CF ２ ClO(CF ２ CF (CF ３ )O) ｎ９ (CF ２ O) ｎ１０ CF ２ COONH ４ (A mixture with an average molecular weight of 750, where n9 and n10 are defined above.) is one example.

[0265] As mentioned above, examples of fluorine-containing anionic surfactants include carboxylic acid-based surfactants and sulfonic acid-based surfactants.

[0266] The fluorine-containing surfactant may be a single fluorine-containing surfactant or a mixture containing two or more fluorine-containing surfactants.

[0267] Fluorine-containing surfactants preferably have a methylene group (-CH ２ -), more preferably without a C-H bond. The molecule contains a methylene group (-CH ２ By using a fluorine-containing surfactant that does not have a C-H bond, polymerization of fluoromonomers can be carried out smoothly in the presence of an aqueous medium.

[0268] The number of H atoms in the hydrophobic group of a fluorine-containing surfactant is preferably 0 or 1, more preferably 0. By using a fluorine-containing surfactant with a small number of H atoms bonded to the carbon atoms constituting the hydrophobic group, polymerization of fluoromonomers in the presence of an aqueous medium can be facilitated. The number of carbon atoms in the hydrophobic group of a fluorine-containing surfactant having both a hydrophobic group and a hydrophilic group is preferably 1 to 50, more preferably 3 to 20, and even more preferably 6 to 12. The hydrophobic group usually constitutes the "part excluding the anionic group" of the molecular structure of the fluorine-containing surfactant described above. As for the hydrophilic group, Y ０Examples of the anionic group include the groups exemplified above. The fluorine-containing surfactant may be a saturated fluorinated surfactant in which all carbon atoms bonded to the hydrophobic group are substituted with fluorine atoms.

[0269] As the fluorine-containing surfactant, among the above-described fluorine-containing anionic surfactants, a compound represented by the general formula (N １ ), a compound represented by the general formula (N ２ ), the general formula (N ４ ): Rf ｎ４ -O-(CY ｎ１ F) ｐ CF ２ -Y ０ (N ４ ) (wherein, Rf ｎ４ is a linear or branched or fully fluorinated alkyl group which may contain an ether bond having 1 to 12 carbon atoms (however, excluding those having -CH ２ -), Y ｎ１ is H or F, p is 0 or 1, and Y ０ is as defined above).), and a compound represented by the general formula (N ５ ): (wherein, X ｎ２ , X ｎ３ and X ｎ４ may be the same or different and are H, F, or a linear or branched or fully fluorinated alkyl group which may contain an ether bond having 1 to 6 carbon atoms (however, excluding those having -CH ２ -), provided that both X ｎ３ and X ｎ４ are not H. Rf ｎ５ is a linear or branched or fully fluorinated alkylene group which may contain an ether bond having 1 to 3 carbon atoms (however, excluding those having -CH ２ -), L is a linking group, and Y ０ is as defined above. However, the total number of carbon atoms of X ｎ２ , X ｎ３ , X ｎ４ and Rf ｎ５ is 18 or less.).), and compounds represented by the formula are exemplified.

[0270] Among the fluorine-containing surfactants mentioned above, the following are included: perfluorocarboxylic acid (I) represented by general formula (I), ω-H perfluorocarboxylic acid (II) represented by general formula (II), perfluoroether carboxylic acid (III) represented by general formula (III), perfluoroalkylalkylene carboxylic acid (IV) represented by general formula (IV), perfluoroalkoxyfluorocarboxylic acid (V) represented by general formula (V), perfluoroalkyl sulfonic acid (VI) represented by general formula (VII), ω-H perfluorosulfonic acid (VII) represented by general formula (VII), perfluoroalkylalkylene sulfonic acid (VIII) represented by general formula (VIII), and general formula (X): Rf ７ -O-Rf ８ -O-CF ２ -COOM (where Rf ７ This includes a linear or branched portion containing ether bonds and / or chlorine atoms with 1 to 6 carbon atoms, or a fully fluorinated alkyl group (wherein -CH ２ (excluding those having -) and Rf ８ This refers to a linear or branched portion having 1 to 6 carbon atoms or a fully fluorinated alkyl group (wherein -CH ２ (Excluding those having -), and M is as defined above. Fluorocarboxylic acid (X) represented by general formula (XI): Rf ９ -O-CY １ FCF ２ -SO ３ M (wherein, Rf ９ This is a linear or branched alkyl group (whereas -CH) that may contain ether bonds between 1 to 12 carbon atoms and may contain chlorine, and is partially or completely fluorinated. ２ (excluding those that have -) and Y １ is H or F, and M is as defined above. ) Alkoxyfluorosulfonic acid (XI), general formula (XII): (In the formula, X １ , X ２ and X ３These may be the same or different linear or branched portion containing H, F and ether bonds having 1 to 6 carbon atoms, or a fully fluorinated alkyl group (however, -CH ２ (excluding those having -), however X ２ and X ３ Both cannot be H, Rf １０ L is a perfluoroalkylene group having 1 to 3 carbon atoms, L is a linking group, and Y ０ is an anionic group.) Compounds represented by (XII), and general formula (XIII): Rf １１ -O-(CF ２ CF (CF ３ )O) ｎ９ (CF ２ O) ｎ１０ CF ２ COOM (where Rf １１ This is a fluoroalkyl group having 1 to 5 carbon atoms and containing chlorine (however, -CH ２ (excluding those having -), where n9 is an integer from 0 to 3, n10 is an integer from 0 to 3, and M is as defined above. At least one selected from the group consisting of compounds (XIII) represented by ) is more preferable. By using these fluorine-containing surfactants, polymerization of fluoromonomers in the presence of an aqueous medium can be carried out smoothly.

[0271] Examples of fluorine-containing surfactants include compounds represented by the following formula. Fluorine-containing surfactants may be mixtures of these compounds. 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 CF２ 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, (In each formula, M is H, metal atom, NR ７ ４ , optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium. ７ (This is either H or an organic group.)

[0272] The amount of fluorine-containing surfactant used is preferably 10 ppm to 10% by mass, more preferably 100 ppm or more by mass, even more preferably 300 ppm or more by mass, even more preferably 5% or less by mass, and even more preferably 1% or less by mass, relative to the aqueous medium.

[0273] (Polymerization without the use of surfactants) In one embodiment, polymerization of fluoromonomers can be carried out substantially in the absence of fluorine-free anionic surfactants. In one embodiment, polymerization of fluoromonomers can be carried out substantially in the absence of fluorine-containing surfactants. In one embodiment, polymerization of fluoromonomers can be carried out substantially in the absence of both fluorine-free anionic surfactants and fluorine-containing surfactants.

[0274] In this disclosure, "substantially in the absence of fluorine-free anionic surfactants" means that the amount of fluorine-free anionic surfactant in the aqueous medium is 10 ppm by mass or less. The amount of fluorine-free anionic surfactant in the aqueous medium is preferably 1 ppm by mass or less, more preferably 100 ppb by mass or less, even more preferably 10 ppb by mass or less, and even more preferably 1 ppb by mass or less. "Polymerization carried out in the absence of fluorine-free anionic surfactants" includes polymerization carried out without intentionally adding fluorine-free anionic surfactants.

[0275] In this disclosure, "substantially absent from fluorine-containing surfactants" means that the amount of fluorine-containing surfactant in the aqueous medium is 10 ppm by mass or less. Preferably, the amount of fluorine-containing surfactant in the aqueous medium is 1 ppm by mass or less, more preferably 100 ppb by mass or less, even more preferably 10 ppb by mass or less, and even more preferably 1 ppb by mass or less. "Polymerization carried out in the absence of fluorine-containing surfactants" includes polymerization carried out without intentionally adding fluorine-containing surfactants.

[0276] In this disclosure, "substantially in the absence of fluorine-free anionic surfactants and fluorine-containing surfactants" means that the total amount of fluorine-free anionic surfactants and fluorine-containing surfactants in the aqueous medium is 10 ppm by mass or less. The total amount of fluorine-free anionic surfactants and fluorine-containing surfactants in the aqueous medium is preferably 1 ppm by mass or less, more preferably 100 ppb by mass or less, even more preferably 10 ppb by mass or less, and even more preferably 1 ppb by mass or less. "Polymerization carried out in the absence of fluorine-free anionic surfactants and fluorine-containing surfactants" includes polymerization carried out without intentionally adding fluorine-free anionic surfactants and fluorine-containing surfactants.

[0277] A method for producing a fluoropolymer by emulsion polymerization in substantially the absence of a fluorine-containing surfactant includes: (1) preparing an aqueous solution containing a water-soluble fluoropolymer by performing a first polymerization of a fluoromonomer in substantially the absence of a fluorine-containing surfactant, in the presence of an aqueous medium and a polymerization initiator; and (2) preparing an aqueous dispersion containing a fluoropolymer by performing a second polymerization of a fluoromonomer in substantially the absence of a fluorine-containing surfactant, in the presence of the aqueous solution, wherein the content of the water-soluble fluoropolymer in the aqueous solution is greater than 0% by mass and less than 1.0% by mass relative to the mass of the aqueous solution; the content of the fluoropolymer in the aqueous dispersion is 15% by mass or more relative to the mass of the aqueous dispersion; the polymerization rate of the first polymerization is 3.0 g / (hr·L) or less; and the second polymerization is performed in substantially the absence of a fluorine-free anionic surfactant from the start of the second polymerization until the content of the fluoropolymer in the aqueous dispersion reaches 10% by mass relative to the mass of the aqueous dispersion.

[0278] This manufacturing method is a novel method discovered by the inventors of this disclosure, and it is possible to produce an aqueous dispersion containing a fluoropolymer while suppressing the adhesion of the generated polymer to the reactor without using a fluorine-containing surfactant.

[0279] Furthermore, known methods may be employed as methods for polymerizing fluoromonomers in the substantially absence of fluorine-free anionic surfactants. Such methods include International Publication Nos. 2024 / 214644, 2024 / 128263, 2009 / 036131, 2010 / 021962, 2010 / 147815, 2012 / 006487, 2012 / 018603, 2012 / 067936, 2013 / 090251, and 2014 / 071129. International Publication Nos. 2014 / 099311, 2014 / 100593, 2015 / 041948, 2016 / 100420, 2016 / 100421, 2017 / 066266, 2022 / 265048, 1996 / 024622, 1997 / 017381, 2019 / 178430, and Japanese Patent Publication No. 48-01895 Japanese Patent Publication No. 7, Japanese Patent Publication No. S49-025041, Japanese Patent Publication No. S49-087739, Japanese Patent Publication No. S49-087740, Japanese Patent Publication No. S49-087741, Japanese Patent Publication No. S52-062391, Japanese Patent Publication No. S55-116713, International Publication No. 2007 / 123123, International Publication No. 2007 / 129735, Japanese Patent Publication No. S49-082791, Japanese Patent Publication No. S53-149291, International Publication No. 2010 / 033269, International Publication No. Examples of methods include those described in International Publication No. 2009 / 013214, International Publication No. 2014 / 206955, International Publication No. 2017 / 046379, International Publication No. 2019 / 101806, International Publication No. 2022 / 106610, International Publication No. 2022 / 128190, International Publication No. 2022 / 135954, International Publication No. 2024 / 033089, International Publication No. 2024 / 165313, and the specification of Russian Patent Invention No. 2158274.

[0280] (Polymer compound having an ionic group (I)) In one embodiment, polymerization of fluoromonomers can be carried out in the presence of polymer compound having an ionic group (I).

[0281] Polymeric compound (I) having an ionic group is a polymer having one or more ionic groups in its molecule. Anionic groups are preferred as the ionic groups.

[0282] The anionic groups of polymer compound (I) include not only anionic groups such as sulfate groups and carboxylate groups, but also acidic groups such as -COOH and -COONH. ４ It contains functional groups that give anionic groups such as acids and bases. Anionic groups include sulfate groups, carboxylate groups, phosphate groups, phosphonate groups, sulfonate groups, or -C(CF ３ ) ２ OM (wherein M is -H, a metal atom, -NR) ７ ４ , optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium, R ７ (where is H or an organic group.) is preferred.

[0283] The ion exchange capacity of polymer compound (I) is, in 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, greater than 2.20 meq / g, 2.50 meq / g or more, 2.60 meq / g or more, 3.00 meq / g or more, and 3.50 meq / g or more. The ion exchange capacity is the content of ionic groups (anionic groups) in polymer compound (I), and can be calculated from the composition of polymer compound (I).

[0284] In polymer compound (I), ionic groups (anionic groups) are typically distributed along the polymer backbone. Polymer compound (I) preferably contains the polymer backbone together with repeating side chains bonded to this backbone, and these side chains have ionic groups.

[0285] The polymer compound (I) preferably contains an ionic group having a pKa of less than 10, more preferably less than 7. The ionic group of the polymer compound (I) is preferably selected from the group consisting of sulfonates, carboxylates, phosphonates, and phosphates.

[0286] The terms "sulfonate, carboxylate, phosphonate, and phosphate" are intended to refer to their respective salts, or the respective acids that can form salts. When salts are used, they are preferably alkali metal salts or ammonium salts. Preferred ionic groups are carboxylate groups and sulfonate groups.

[0287] As for ionic groups, -SO ３ M, -COOM, or -P(O)(OM) ２ This is preferable. Regarding "M" in the ionic group (anionic group), the term "anionic group (A)" will be described later. ０ This is the same as the "M" in the )

[0288] The polymer compound (I) is preferably a polymer compound in which the proportion of hydrogen atoms bonded to carbon atoms that are replaced by fluorine atoms is 50% or more. The "proportion of hydrogen atoms bonded to carbon atoms that are replaced by fluorine atoms" is determined as the ratio of the number of fluorine atoms to the total number of hydrogen atoms bonded to carbon atoms and halogen atoms (including fluorine atoms) bonded to carbon atoms.

[0289] The polymer compound (I) preferably has an ion exchange rate (IXR) of 53 or less. The IXR is defined as the number of carbon atoms in the polymer backbone relative to the ionic group. Precursor groups that become ionic upon hydrolysis (for example, -SO ２ F) is not considered an ionic group for the purpose of determining IXR.

[0290] IXR is preferably 0.5 or higher, more preferably 1 or higher, even more preferably 3 or higher, even more preferably 4 or higher, especially preferably 5 or higher, and particularly preferably 8 or higher. Furthermore, IXR is more preferably 43 or lower, even more preferably 33 or lower, and particularly preferably 23 or lower.

[0291] The polymer compound (I) is preferably water-soluble. Water solubility means the property of readily dissolving or dispersing in an aqueous medium. The water-soluble polymer compound (I) is such that, for example, its particle size cannot be measured by dynamic light scattering (DLS), or a particle size of 10 nm or less is observed.

[0292] The number-average molecular weight of polymer compound (I) is 0.1 × 10⁻⁶. ４ The above is preferable, 0.2 × 10 ４ The above is more preferable, 0.3 × 10 ４ The above is even more preferable, 0.4 × 10 ４ The above is even more preferable, 0.5 × 10 ４ The above is particularly preferable, 1.0 × 10 ４ The above is particularly preferred, 3.0 × 10 ４ The above is particularly preferred, 3.1 × 10 ４ The above is the most preferable. Also, 75.0 × 10 ４ The following is preferable: 50.0 × 10 ４ The following is more preferable: 40.0 × 10 ４ The following is even more preferable: 30.0 × 10 ４ The following is particularly preferred: 20.0 × 10 ４ The following are particularly preferred. The number-average molecular weight and weight-average molecular weight are values ​​calculated using monodisperse polystyrene as a standard by gel permeation chromatography (GPC). If measurement by GPC is not possible, the number-average molecular weight of polymer compound (I) can be determined by 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.

[0293] The lower limit of the weight-average molecular weight of polymer compound (I) is, in order of preference, 0.2 × 10⁻⁶. ４ The above is 0.4 x 10 ４ The above is 0.6 × 10 ４ The above is 0.8 x 10 ４ The above is 1.0 x 10 ４ The above is 2.0 x 10 ４ The above is 5.0 x 10 ４ The above is 10.0 x 10 ４ The above is 15.0 x 10 ４ The above is 20.0 x 10 ４ The above is 25.0 x 10 ４ That concludes the explanation. Furthermore, the upper limit of the weight-average molecular weight of polymer compound (I) is, in order of preference, 150.0 × 10⁻⁶. ４Below, 100.0 x 10 ４ Below, 60.0 x 10 ４ Below, 50.0 x 10 ４ Below, 40.0 x 10 ４ The following applies:

[0294] The viscosity of the aqueous solution of polymer compound (I) is preferably 5.0 mPa.s or higher, more preferably 8.0 mPa.s or higher, even more preferably 10.0 mPa.s or higher, particularly preferably 12.0 mPa.s or higher, most preferably 14.0 mPa.s or higher, preferably 100.0 mPa.s or lower, more preferably 50.0 mPa.s or lower, even more preferably 25.0 mPa.s or lower, and especially preferably 20.0 mPa.s or lower.

[0295] The viscosity of an aqueous solution of polymer compound (I) can be determined by adjusting the content of polymer compound (I) in the aqueous solution to 33% by mass relative to the aqueous solution, and then measuring the viscosity of the resulting aqueous solution at 20°C using a tuning fork vibratory viscometer (model number: SV-10) manufactured by A&D Co., Ltd.

[0296] The critical micelle concentration (CMC) of polymer compound (I) is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less.

[0297] The critical micelle concentration of polymer compound (I) can be determined by measuring its surface tension. Surface tension can be measured, for example, using a surface tension meter, model DY-300, manufactured by Kyowa Interfacial Chemical Co., Ltd.

[0298] The acid value of polymer compound (I) is preferably 60 or higher, more preferably 90 or higher, even more preferably 120 or higher, particularly preferably 150 or higher, most preferably 180 or higher, and there is no particular upper limit, but it is preferably 300 or lower.

[0299] The acid value of polymer compound (I) is determined by whether polymer compound (I) has anionic groups other than acidic functional groups, such as -COOM, -SO ３M, -OSO ３ M or -C (CF ３ ) ２ OM (M is a metal atom, NR ７ ４ , optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium, R ７ If the group has H or an organic group, these groups can be converted to acidic groups and then measured by acid-base titration.

[0300] As the polymer compound (I), a polymer containing polymerization units (I) based on monomer (I) represented by general formula (I) is preferred. CX １ X ３ = CX ２ R(-CZ) １ Z ２ -A ０ ) ｍ (I) (wherein, X １ and X ３ These are F, Cl, H, or CF, each independently. ３ X ２ is H, F, alkyl group or fluorine-containing alkyl group; A ０ is an anionic group; R is a linking group; Z １ and Z ２ Each of these is independently H, F, an alkyl group, or a fluorinated alkyl group; m is an integer of 1 or more.

[0301] The polymer compound (I) is a precursor group that becomes ionic upon hydrolysis, for example, -SO ２ F, -CN, -OCF ３ , -OCF ２ CF ３ , -OCF ２ CF ２ CF ３ A polymer compound may be obtained using monomers containing such compounds, and then subjected to hydrolysis or other processes to obtain a polymer containing polymerization units (I) based on monomer (I) represented by general formula (I).

[0302] R is a linking group. In this disclosure, “linking group” is an (m+1) valence linking group, and if m is 1, it is a divalence 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. There is no upper limit, but for example, it may be 100 or less, or 50 or less.

[0303] 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 esters, amides, sulfonamides, carbonyls, carbonates, urethanes, ureas, and carbamates. The above linking group may not contain carbon atoms and may contain catenary heteroatoms such as oxygen, sulfur, or nitrogen.

[0304] m is an integer of 1 or more, preferably 1 or 2, and more preferably 1. If m is an integer of 2 or more, Z １ Z ２ and A ０ These may be the same or different. Next, a preferred configuration will be described for the case where m is 1 in general formula (I).

[0305] R is preferably a catenary heteroatom such as oxygen, sulfur, or nitrogen, or a divalent organic group.

[0306] 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. Furthermore, R may be linear or branched, and may be cyclic or acyclic. In addition, R may contain a functional group (for example, an ester, ether, ketone (keto group), amine, halide, etc.).

[0307] R may also be a non-fluorinated divalent organic group, or a partially fluorinated or perfluorinated divalent organic group.

[0308] R may be, for example, a hydrocarbon group in which no fluorine atoms are bonded to a carbon atom, a hydrocarbon group in which some of the hydrogen atoms bonded to a carbon atom are replaced by fluorine atoms, or a hydrocarbon group in which all of the hydrogen atoms bonded to a carbon atom are replaced by fluorine atoms. These may contain oxygen atoms, double bonds, or functional groups.

[0309] R is preferably a hydrocarbon group having 1 to 100 carbon atoms, which may contain an ether bond or a keto group, and the hydrocarbon group may have some or all of the hydrogen atoms bonded to the carbon atoms substituted with fluorine.

[0310] Preferably, R is -(CH ２ ) ａ -, - (CF ２ ) ａ -, - (CF ２ ) ａ -O-, -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 -, -O[(CF ２ ) ａ -O] ｂ - [(CF ２ ) ｃ -O]ｄ -, -O-[CF ２ CF (CF ３ )O] ａ - (CF ２ ) ｂ -, -O-(CF ２ ) ａ -O-[CF(CF ３ ) CF ２ O] ｂ -, -O-[CF ２ CF (CF ３ )O] ａ - (CF ２ ) ｂ -O-, -O-[CF ２ CF (CF ３ )O] ａ - (CF ２ ) ｂ -O-[CF(CF ３ ) CF ２ O] ｃ -, -[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 combination selected from these. In the formula, a, b, c, and d are independently at least 1. A, b, c, and d may 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.

[0311] More comfortably as R, -O-CF ２ -, -O-CF ２ CF ２ -, -O-CF ２ CF ２ -O-, -O-CF ２ CF ２ CF ２ -, -O-CF ２ CF ２ CF ２ -O-, -O-CF ２ CF (CF ３ ) -O-, -O-CF ２ CF ２ -O-CF(CF ３ ) CF ２ -O-, -O-CF ２ CF (CF ３ )-O-CF ２ CF ２ -O-, and -O-CF ２ CF (CF ３ )-O-CF ２ It is at least one selected from the following.

[0312] For R, the general formula is (r1): -CF ２ -O-(CX) ６ ２ ) ｅ - {O-CF(CF ３ )} ｆ - (O) ｇ - (r1) (wherein, X ６ Each is independently H, F, or CF ３ A divalent group represented by the general formula (r2): -CF ２ -O-(CX) ７ ２ ) ｅ - (O) ｇ - (r2) (wherein, X ７ Each is independently H, F, or CF ３ A divalent group represented by (where e is an integer from 0 to 3 and g is 0 or 1) is more preferable.

[0313] A suitable example of R is -CF ２-O-, -CF ２ -O-CF ２ -, -CF ２ -O-CH ２ -, -CF ２ -O-CH ２ CF ２ -, -O-CF ２ -, -O-CF ２ CF ２ -, -O-CF ２ CF ２ CF ２ -, -O-CF ２ CF ２ CF ２ CF ２ -, -O-CF ２ CF (CF ３ )-O-CF ２ -, -O-CF ２ CF (CF ３ )-O-CF 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 - are some examples. In particular, R is preferably a perfluoroalkylene group which may contain an oxygen atom, specifically -CF ２ -O-, -CF ２ -O-CF ２ -, -O-CF ２-, -O-CF ２ CF ２ -, -O-CF ２ CF (CF ３ )-O-CF ２ -, -O-CF ２ CF (CF ３ )-O-CF ２ 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.

[0314] General formula (I) -R-CZ １ Z ２ - For 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 Each is independently H, F, or CF ３ where e is an integer from 0 to 3, f is an integer from 0 to 3, g is 0 or 1, Z １ and Z ２ Preferably, each of these is independently represented as H, F, an alkyl group, or a fluorine-containing alkyl group, and in formula (s1), Z １ and Z ２ is F or CF ３ More preferably, one is F and the other is CF ３ It is even more preferable that this be the case.

[0315] Furthermore, in general formula (I), -R-CZ １ Z ２ - For general formula (s2): -CF ２-O-(CX) ７ ２ ) ｅ - (O) ｇ -CZ １ Z ２ - (s2) (wherein, X ７ Each is independently H, F, or CF ３ where e is an integer from 0 to 3, g is 0 or 1, and Z １ and Z ２ Preferably, each of these is independently represented as H, F, an alkyl group, or a fluorine-containing alkyl group, and in formula (s2), Z １ and Z ２ is F or CF ３ More preferably, one is F and the other is CF ３ It is even more preferable that this be the case.

[0316] General formula (I) -R-CZ １ Z ２ - As for -CF ２ -O-CF ２ -, -O-CF ２ CF ２ -, -O-CF ２ CF ２ CF ２ -, -O-CF ２ CF ２ CF ２ CF ２ -, -O-CF ２ CF (CF ３ )-O-CF ２ -, -O-CF ２ CF (CF ３ )-O-CF ２ CF ２ -, -O-CF ２ CF (CF ３ )-O-CF ２ CF ２ 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 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 )-、または、-CF ２ - O - CF (CF ３ CF ２ - O - C (CF ３ ) ２- is preferred, -O-CF ２ CF ２ -, -O-CF ２ CF ２ CF ２ -, -O-CF ２ CF ２ CF ２ CF ２ -, -O-CF ２ CF (CF ３ )-O-CF ２ -, -O-CF ２ CF (CF ３ )-O-CF ２ CF ２ -, -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 preferable, -O-CF ２ CF ２ -, -O-CF ２ CF (CF ３ )-O-CF ２ CF ２ - is even more preferable.

[0317] The polymer compound (I) is also preferably highly fluorinated. For example, the phosphate group moiety (e.g., CH ２ OP(O)(OM) ２ ) and sulfate group moiety (for example, CH ２ OS(O) ２ Anionic groups such as OM (A ０Except for the above, it is preferable that 80% or more, 90% or more, 95% or more, or 100% of the C-H bonds in polymer compound (I) are substituted with C-F bonds.

[0318] Monomer (I) and polymer compound (I) have an anionic group (A ０ Except for the above, it is also preferable that it has a C-F bond and does not have a C-H bond. That is, in general formula (I), X １ , X ２ , and X ３ Preferably, all of the elements are F, and R is a perfluoroalkylene group having one or more carbon atoms. The perfluoroalkylene group may be linear or branched, cyclic or acyclic, and may contain at least one catenary heteroatom. The number of carbon atoms in the perfluoroalkylene group may be 2 to 20 or 4 to 18.

[0319] The monomer (I) and polymer compound (I) may be partially fluorinated. That is, the monomer (I) and polymer compound (I) may have an anionic group (A ０ Except for the above, it is also preferable to have at least one hydrogen atom bonded to a carbon atom, and at least one fluorine atom bonded to a carbon atom.

[0320] Anionic group (A ０ ) is -SO ２ M, -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 OSO ３ M, -P(O)(OM) ２ , -SO２ 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 It can be OM. In particular, -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, -P(O)(OM) ２ or -C(CF ３ ) ２ OM is more preferred, -SO ３ M, -COOM, or -P(O)(OM) ２ More preferably, -SO ３ M or -COOM are particularly preferred.

[0321] M is H, metal atom, NR ７ ４ , optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium, R ７ is either H or an organic group.

[0322] Examples of metal atoms include alkali metals (Group 1) and alkaline earth metals (Group 2), with Na, K, or Li being preferred.

[0323] M can be -H, a metal atom, or NR ７ ４ Preferably, -H, alkali metals (Group 1), alkaline earth metals (Group 2), or NR ７ ４ More preferably, -H, -Na, -K, -Li or NH４ More preferably, -H, -Na, -K or NH ４ More preferably, -H, -Na or NH ４ -H or -NH is particularly preferred. ４ Most preferable.

[0324] In polymer compound (I), each polymerization unit (I) may have different anionic groups, or it may have the same anionic group.

[0325] The monomer (I) is preferably a monomer (1) represented by general formula (1). The polymer compound (I) is preferably a polymer compound (1) containing a polymerization unit (1) based on the monomer represented by general formula (1). CX ２ =CY(-CZ) ２ -O-Rf-A) (1) (wherein X is the same or different -H or F, Y is -H, -F, alkyl group or fluorine-containing alkyl group, and Z is the same or different -H, -F, alkyl group or 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 having 2 to 100 carbon atoms. A is -COOM, -SO ３ M, -OSO ３ M or -C (CF ３ ) ２ OM (where M is -H, metal atom, -NR) ７ ４ , optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium, R ７ (wherein X, Y, and Z are H or organic groups, at least one of them contains a fluorine atom.)

[0326] The polymer compound (1) may be a homopolymer of monomer (1) represented by general formula (1), or it may be a copolymer with other monomers.

[0327] The above-mentioned fluorine-containing alkylene groups having ether bonds with 2 to 100 carbon atoms do not include structures where the oxygen atom is at the terminal end, and are alkylene groups that contain ether bonds between carbon atoms.

[0328] In general formula (1), X is either -H or F. X may be both -F, or at least one of them may be -H. For example, one may be -F and the other -H, or both may be -H.

[0329] In 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 one or more carbon atoms. The number of carbon atoms of the alkyl group is preferably 6 or less, more preferably 4 or less, and even more preferably 3 or less. The fluorine-containing alkyl group is an alkyl group that contains at least one fluorine atom, and may have one 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 even more preferably 3 or less. As for Y, it may be -H, -F, or CF ３ -F is preferred, and -F is more preferred.

[0330] In general formula (1), Z is the same or different -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 one or more carbon atoms. The number of carbon atoms of the alkyl group is preferably 6 or less, more preferably 4 or less, and even more preferably 3 or less. The fluorine-containing alkyl group is an alkyl group that contains at least one fluorine atom, and may have one 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 even more preferably 3 or less. As for Z, -H, -F, or CF ３ -F is preferred, and -F is more preferred.

[0331] 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.

[0332] 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 having 2 to 100 carbon atoms.

[0333] The number of carbon atoms in the above-mentioned fluorine-containing alkylene group is preferably 2 or more. Furthermore, the number of carbon atoms in the above-mentioned fluorine-containing alkylene group is preferably 30 or less, more preferably 20 or less, even more preferably 10 or less, particularly preferably 6 or less, and most preferably 3 or less. The above-mentioned fluorine-containing alkylene group is -CF ２ -ien-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 - are examples. The above fluorine-containing alkylene group is preferably a perfluoroalkylene group.

[0334] The number of carbon atoms in the fluorinated alkylene group having the ether bond described above is preferably 3 or more. Furthermore, the number of carbon atoms in the fluorinated alkylene group having the ether bond described above is preferably 60 or less, more preferably 30 or less, even more preferably 12 or less, particularly preferably 9 or less, and most preferably 6 or less. The fluorinated alkylene group having the ether bond described above has a general formula, for example: (In the formula, Z １ is F or CF ３ ;Z ２ and Z ３ H or F; Z ４ is H, F or CF ３ It is also preferable that the base is a divalent base represented by (p1 + q1 + r1 being integers from 1 to 10; s1 being 0 or 1; and t1 being an integer from 0 to 5).

[0335] Specifically, the fluorine-containing alkylene group having the above ether bond is -CF ２ CF (CF ３ ) OCF ２ -, -CF (CF ３ ) CF ２-O-CF(CF ３ )-,-(CF(CF ３ ) CF ２ -O) ｎ -CF (CF ３ ) - (where 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 - are examples. The fluorine-containing alkylene group having the ether bond is preferably a perfluoroalkylene group.

[0336] In general formula (1), A is -COOM, -SO ３ M, -OSO ３ M or -C (CF ３ )２ OM (M is H, metal atom, NR) ７ ４ , optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium, R ７ ( is H or an organic group).

[0337] R ７ For example, H or C １－１０ The organic group is preferably H or C １－４ The organic group is more preferably H or C １－４ A alkyl group is even more preferred.

[0338] Examples of metal atoms include alkali metals (Group 1) and alkaline earth metals (Group 2), with Na, K, or Li being preferred.

[0339] M can be H, a metal atom, or NR ７ ４ Preferably, H, alkali metals (Group 1), alkaline earth metals (Group 2), or NR ７ ４ More preferably, H, Na, K, Li or NH ４ More preferably, H, Na, K or NH ４ More preferably, H, Na or NH ４ H or NH is particularly preferred. ４ Most preferable.

[0340] A can be -COOM or -SO ３ M is preferred.

[0341] Examples of monomers represented by general formula (1) include general formula (1a): CX ２ = CFCF ２ -O-(CF(CF ３ ) CF ２ O) ｎ５ -CF (CF ３ A monomer represented by )-A (1a) (wherein each X is the same and represents either F or H, n5 represents 0 or an integer from 1 to 10, and A is the same as defined above) is given as an example.

[0342] In general formula (1a), 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 that it is possible to obtain particles with a small primary particle diameter.

[0343] The polymer compound (1) may be a homopolymer of monomers represented by general formula (1a), or it may be a copolymer with other monomers.

[0344] The monomer (1) is preferably a monomer represented by general formula (1A). The polymerization unit (1) is preferably a polymerization unit (1A) based on the monomer represented by general formula (1A). CH ２ =CF(-CF) ２ (-O-Rf-A) (1A) (wherein Rf and A are the same as above.)

[0345] The polymer compound (1) may be a homopolymer of monomers represented by general formula (1A), or it may be a copolymer with other monomers.

[0346] Specifically, the monomer represented by formula (1A) is the general formula

[0347]

[0348] (In the formula, Z １ is F or CF ３ ;Z ２ and Z ３ H or F; Z ４ is H, F or CF ３ p1 + q1 + r1 are integers from 0 to 10; s1 is 0 or 1; t1 is an integer from 0 to 5, where Z ３ and Z ４ A monomer represented by (where both are H, p1 + q1 + r1 + s1 is not 0; A is the same as in the definition above) can be cited. More specifically,

[0349]

[0350] These are some of the preferred options, among others

[0351]

[0352] It is preferable that this be the case.

[0353] The monomer represented by the general formula (1A) is preferably -COOM where A 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 Preferably, at least one selected from the group consisting of COOM (wherein M is the same as defined above), CH ２ = CFCF ２ OCF (CF ３ ) COOM is more preferable.

[0354] The monomer (I) is preferably a monomer (2) represented by general formula (2). The polymer compound (I) is also preferably a polymer compound (2) containing polymerization units (2) based on the monomer represented by general formula (2). CX ２ =CY(-O-Rf-A) (2) (wherein X is the same or different -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 or a keto group having 2 to 100 carbon atoms. A is the same as above.)

[0355] The monomer (I) is preferably a monomer (3) represented by general formula (3). The polymer compound (I) is also preferably a polymer compound (3) containing polymerization units (3) based on the monomer represented by general formula (3). CX ２ =CY(-Rf-A) (3) (wherein X is the same or different -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 having 2 to 100 carbon atoms. A is the same as above.)

[0356] The polymer compound (I) may be a homopolymer consisting only of polymerization units (I), or it may be a copolymer containing polymerization units (I) and polymerization units based on other monomers copolymerizable with the monomer represented by general formula (I). From the viewpoint of solubility in aqueous media, a homopolymer consisting only of polymerization units (I) is preferred. The polymerization units (I) may be the same or different in each appearance, and the polymer compound (I) may contain polymerization units (I) based on two or more different monomers represented by general formula (I).

[0357] Polymeric compound (I) typically has end groups. These end groups are 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 contain at least one additional catenary heteroatom. The alkyl or fluoroalkyl group preferably has 1 to 20 carbon atoms. These end groups are generally generated from initiators or chain transfer agents used to form polymeric compound (I), or generated during the chain transfer reaction.

[0358] In polymer compound (I), the content of polymerization units (I) is, in 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, and 90 mol% or more, relative to the total polymerization units. It is particularly preferable that the content of polymerization units (I) be substantially 100 mol%, and it is most preferable that polymer compound (I) consists only of polymerization units (I).

[0359] In polymer compound (I), the content of polymerization units based on other monomers copolymerizable with the monomer represented by general formula (I) is, in order of increasing preference, 99.0 mol% or less, 97.0 mol% or less, 95.0 mol% or less, 90 mol% or less, 80 mol% or less, 70 mol% or less, 60 mol% or less, 50 mol% or less, 40 mol% or less, 30 mol% or less, 20 mol% or less, and 10 mol% or less, relative to the total polymerization units. It is particularly preferable that the content of polymerization units based on other monomers copolymerizable with the monomer represented by general formula (I) be substantially 0 mol%, and it is most preferable that polymer compound (I) does not contain polymerization units based on other monomers.

[0360] Examples of polymer compounds (I) having ionic groups include Japanese Patent Publication No. 60-118228, Japanese Patent Publication No. 02-225550, International Publication No. 2007 / 142888, International Publication No. 2009 / 055521, International Publication No. 2010 / 075359, International Publication No. 2011 / 008381, International Publication No. 2014 / 099453, International Publication No. 2001 / 030873, and International Publication No. 200 You may use the materials described in International Publication No. 4 / 067588, International Publication No. 2006 / 135825, International Publication No. 2012 / 082707, International Publication No. 2013 / 085864, International Publication No. 2019 / 215636, International Publication No. 2019 / 178430, International Publication No. 2018 / 167190, International Publication No. 2024 / 020782, International Publication No. 2024 / 020783, etc.

[0361] The amount of polymer compound (I) having ionic groups used is preferably 0.0001% by mass or more, more preferably 0.001% by mass or more, even more preferably 0.01% by mass or more, particularly preferably 0.02% by mass or more, preferably 10% by mass or less, and more preferably 5% by mass or less, relative to the aqueous medium.

[0362] (Additives) Additives may be used in the polymerization described above. Examples of such additives include buffers, pH adjusters, stabilizing agents, and dispersion stabilizers.

[0363] Preferred stabilizing agents include paraffin wax, fluorinated oils, fluorinated solvents, and silicone oils. Stabilizing agents may be used individually or in combination of two or more. Paraffin wax is more preferred as a stabilizing agent. Paraffin wax may be liquid, semi-solid, or solid at room temperature, but saturated hydrocarbons with 12 or more carbon atoms are preferred. The melting point of paraffin wax is usually preferably 40 to 65°C, and more preferably 50 to 65°C.

[0364] The amount of stabilizing agent used is preferably 0.1 to 12% by mass, and more preferably 0.1 to 8% by mass, based on the mass of the aqueous medium used. It is desirable that the stabilizing agent is sufficiently hydrophobic and completely separates from the aqueous dispersion after polymerization so as not to become a contaminating component.

[0365] (Fluoromers) Fluoromers having at least one double bond are preferred. Examples of fluoroomers include tetrafluoroethylene [TFE], hexafluoropropylene [HFP], chlorotrifluoroethylene [CTFE], vinyl fluoride, vinylidene fluoride [VDF], trifluoroethylene, fluoroalkyl vinyl ether, fluoroalkylethylene, fluoroalkyl allyl ether, trifluoropropylene, pentafluoropropylene, trifluorobutene, tetrafluoroisobutene, hexafluoroisobutene, and general formula (100): CHX １０１ = CX １０２ Rf １０１ (In the formula, X １０１ and X １０２ In this case, one is H, the other is F, and Rf １０１ Preferably, the monomer is at least one selected from the group consisting of fluoromonomers (represented by a linear or branched fluoroalkyl group having 1 to 12 carbon atoms), fluorinated vinyl heterocyclic compounds, and monomers that provide a crosslinking site.

[0366] Examples of the above fluoroalkyl vinyl ether include General formula (110): CF ２ =CF - ORf １１１ (wherein, Rf １１１represents a perfluoroorganic group. ) Fluoromer represented by general formula (120): CF ２ = CF - OCH ２ -Rf １２１ (wherein, Rf １２１ Fluoromers represented by perfluoroalkyl groups 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. Fluoromers 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 from 1 to 4. n is an integer from 1 to 4.) Fluoromers represented by the formula (150): CF ２ =CF - O - (CF ２ CFY １５１ -O) ｎ - (CFY １５２ ) ｍ -A １５１ (In the formula, Y １５１ These are fluorine atoms, chlorine atoms, and -SO ２ Represents an F group or a perfluoroalkyl group. Perfluoroalkyl groups consist of etheric oxygen and -SO ２ It may include an F element. n represents an integer from 0 to 3. n Y elements １５１ They may be the same or they may be different. １５２ is a fluorine atom, a chlorine atom, or -SO ２ F represents a base. m represents an integer from 1 to 5. m Y １５２ They may be the same or they may be different. A １５１ is, -SO ２ X １５１ , -COZ １５１or -POZ １５２ Z １５３ It represents X １５１ is F, Cl, Br, I, -OR １５１ or -NR １５２ R １５３ It represents Z. １５１ Z １５２ and Z １５３ These are the same or different, -NR １５４ R １５５ OR １５６ Represents R １５１ , R １５２ , R １５３ , R １５４ , R １５５ and R １５６ It is preferable that the group consists of at least one selected from the group comprising fluoromonomers represented by ), which may contain H, ammonium, alkali metal, fluorine atoms, alkyl groups, aryl groups, or sulfonyl-containing groups, either identically or differently.

[0367] In this disclosure, the term "perfluoroorganic group" means an organic group in which all hydrogen atoms bonded to a carbon atom are replaced with fluorine atoms. The perfluoroorganic group may have an ether oxygen atom.

[0368] As a fluoromonomer represented by general formula (110), Rf １１１ Examples of fluoromonomers include those in which the perfluoroalkyl group has 1 to 10 carbon atoms. The number of carbon atoms in the perfluoroalkyl group is preferably 1 to 5.

[0369] Examples of perfluoroorganic groups in general formula (110) include perfluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluorobutyl group, perfluoropentyl group, and perfluorohexyl group. Furthermore, as fluoromonomers represented by general formula (110), Rf １１１ Rf １１１ The formula is as follows:

[0370]

[0371] (In the formula, m represents an integer from 0 to 4.) The base Rf is represented by the following formula:

[0372] CF ３ CF ２ CF ２ - (O-CF(CF ３ ) - CF ２ ) ｎ Examples include the base represented by - (wherein n represents an integer from 1 to 4).

[0373] Among the fluoromonomers represented by general formula (110), there is general formula (160): CF ２ =CF - ORf １６１ (wherein, Rf １６１ Rf represents a perfluoroalkyl group having 1 to 10 carbon atoms. Fluoromonomers represented by Rf are preferred. １６１ It is preferable that it is a perfluoroalkyl group having 1 to 5 carbon atoms.

[0374] The fluoroalkyl vinyl ether is preferably at least one selected from the group consisting of fluoromonomers represented by general formulas (160), (130), and (140).

[0375] The fluoromonomer represented by general formula (160) is preferably at least one selected from the group consisting of perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether), and perfluoro(propyl vinyl ether), and more preferably at least one selected from the group consisting of perfluoro(methyl vinyl ether) and perfluoro(propyl vinyl ether).

[0376] As a fluoromonomer represented by 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 ３It is preferable that it be at least one selected from the group consisting of the following:

[0377] Fluoromers represented by general formula (140) include 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 F and CF ２ = CFO (CF ２ CF (CF ３ )O) ２ (CF ２ ) ２ It is preferable that it be at least one selected from the group consisting of F.

[0378] As a fluoromonomer represented by 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) ２ At least one selected from the group consisting of is preferred.

[0379] As a fluoromonomer represented by the general formula (100), Rf １０１ A fluoromonomer in which is a linear fluoroalkyl group is preferred, and Rf １０１ A fluoromonomer in which the linear perfluoroalkyl group is is more preferred.１０１ The number of carbon atoms is preferably 1 to 6. The fluoromonomer represented by the general formula (100) is 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 Examples include (Z-form), and among them, CH ２ = CFCF ３ 2,3,3,3-tetrafluoropropylene, represented by [formula], is preferred.

[0380] Fluoroalkylethylenes include those with the general formula (170): CH ２ = CH - (CF ２ ) ｎ -X １７１ (In the formula, X １７１ is H or F, and n is an integer from 3 to 10. Fluoroalkylethylene represented by ) is preferred, CH ２ = CH - C ４ F ９ , and CH ２ = CH - C ６ F １３ It is more preferable that it be at least one selected from the group consisting of the following:

[0381] Examples of the above fluoroalkyl allyl ethers include, for example, General formula (180): CF ２ = CF - CF ２ -ORf １１１ (wherein, Rf １１１ ) represents a perfluoroorganic group. Examples include fluoromonomers represented by ).

[0382] Rf of general formula (180) １１１ Rf of general formula (110) １１１ It is the same as Rf １１１ As such, a perfluoroalkyl group having 1 to 10 carbon atoms or a perfluoroalkoxyalkyl group having 1 to 10 carbon atoms is preferred. As a fluoroalkyl allyl ether represented by general formula (180), 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 , and CF ２ = CF - CF ２ -O-C ４ F ９ Preferably, at least one selected from the group consisting of CF ２ = CF - CF ２ -O-C ２ F ５ CF ２ = CF - CF ２ -O-C ３ F ７ , and CF ２ = CF - CF ２ -O-C ４ F ９ More preferably, at least one selected from the group consisting of CF ２ = CF - CF ２ -O-CF ２ CF ２ CF ３ That is even more preferable.

[0383] The above fluorinated vinyl heterocyclic material is general formula (230): (In the formula, X ２３１ and X ２３２ These are independently F, Cl, a methoxy group, or a fluorinated methoxy group, and Y ２３１ is formula Y ２３２ or formula Y ２３３ That is the case.

[0384] (In the formula, Z２３１ and Z ２３２ A fluorinated vinyl heterocyclic compound represented by )) is independently F or a fluorinated alkyl group having 1 to 3 carbon atoms.

[0385] As monomers that provide crosslinking sites, 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, CF ２ = CFOCF ２ CF ２ CH ２ I, CH 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, CH ２ =CH(CF ２ ) ２ CH=CH ２ ,CH ２ =CH(CF ２ ) ６ CH=CH ２ , and CF ２ = CFO (CF ２ ) ５Preferably, it is at least one selected from the group consisting of 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 it be at least one selected from the group consisting of I.

[0386] In the polymerization described above, the fluoromonomer may be polymerized with a fluorine-free monomer. Examples of the fluorine-free monomer include hydrocarbon monomers that are reactive with the fluoromonomer.

[0387] Examples of the hydrocarbon monomers mentioned above 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 acetate, vinyl propionate, n-butyrate, vinyl isobutyrate, vinyl valerate, vinyl pivalate, vinyl caproate, vinyl caprylate, vinyl caprate, vinyl versatate, vinyl laurate, vinyl myristate, vinyl palmitate, vinyl stearate, vinyl benzoate, p-t-butylbenzoate, vinyl cyclohexanecarboxylate, vinyl monochloroacetate, vinyl adipate, vinyl acrylate, vinyl methacrylate, vinyl crotate, vinyl sorbate, vinyl cinnamate, vinyl undecylenate, vinyl hydroxyacetate, and hydroxyvinyl acetate. Examples include vinyl esters such as vinyl oxypropioate, 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; and (meth)acrylic acid 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.

[0388] The above fluorine-free monomers may also be functional group-containing hydrocarbon monomers (excluding monomers that provide crosslinking sites). Examples of the above functional group-containing hydrocarbon monomers 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 carboxyl groups such as acrylic acid, methacrylic acid, itaconic acid, succinic acid, succinic anhydride, fumaric acid, fumaric anhydride, crotonic acid, maleic acid, maleic anhydride, and perfluorobutenoic acid; fluorine-free monomers having sulfo groups such as vinyl sulfonic acid; fluorine-free monomers having glycidyl groups such as glycidyl vinyl ether and glycidyl allyl ether; fluorine-free monomers having amino groups such as aminoalkyl vinyl ether and aminoalkyl allyl ether; fluorine-free monomers having amide groups such as (meth)acrylamide and methylolacrylamide; and fluorine-free monomers having nitrile groups such as acrylonitrile and methacrylonitrile.

[0389] In the manufacturing method of this disclosure, it is preferable to use at least TFE as the fluoromonomer. In one embodiment, TFE, or a combination of TFE and a fluoromonomer other than TFE, is used as the fluoromonomer.

[0390] In the polymerization described above, a desired fluoropolymer can be obtained by polymerizing one or more of the above-mentioned fluoromonomers.

[0391] The above polymerization can yield an aqueous dispersion containing the above fluoropolymer. The fluoropolymer is typically present in a concentration of 8 to 50% by mass of the aqueous dispersion obtained by the above polymerization. In the aqueous dispersion, the preferred lower limit of the fluoropolymer concentration is 10% by mass, the more preferred lower limit is 15% by mass, the preferred upper limit is 40% by mass, and the more preferred upper limit is 35% by mass.

[0392] The fluoropolymer content in the aqueous dispersion is 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 residue after heating, and calculating the percentage of the mass of the residue to the mass of the aqueous dispersion (1 g).

[0393] In one embodiment, polytetrafluoroethylene (PTFE) is produced using at least TFE as the fluoromonomer. In one embodiment of the production method, polytetrafluoroethylene (PTFE) is produced using only TFE, a mixture of TFE and HFP, or a mixture of TFE and fluoroalkyl vinyl ether as the fluoromonomer.

[0394] (Fluoropolymers) Fluoropolymers can be obtained by the manufacturing method of the present disclosure. Examples of fluoropolymers include TFE polymers in which the monomer with the highest mole fraction in the polymer (hereinafter referred to as "most abundant monomer") is TFE, VDF polymers in which the most abundant monomer is VDF, and CTFE polymers in which the most abundant monomer is CTFE.

[0395] The above fluoropolymer preferably has an ion exchange rate (IXR) higher than 53. Preferred fluoropolymers either 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 the preferred fluoropolymer is preferably 1000 or higher, more preferably 2000 or higher, and even more preferably 5000 or higher.

[0396] The TFE polymer may preferably be a TFE homopolymer, or a copolymer consisting 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 ethers) having an alkyl group having 1 to 5 carbon atoms, particularly 1 to 3 carbon atoms; fluorodioxole; perfluoroalkylethylene; ω-hydroperfluoroolefin, etc.

[0397] The TFE polymer may also be a copolymer of TFE and one or more fluorine-free monomers. Examples of the fluorine-free monomers include alkenes such as ethylene and propylene; vinyl esters; and vinyl ethers. The TFE polymer may also be a copolymer of TFE and one or more fluorine-containing monomers having 2 to 8 carbon atoms and one or more fluorine-free monomers.

[0398] The VDF polymer may preferably be a VDF homopolymer [PVDF], or a copolymer consisting of (1) VDF, (2) one or more fluoroolefins other than VDF having 2 to 8 carbon atoms, particularly TFE, HFP, or CTFE, and (3) a perfluoro(alkyl vinyl ether) having an alkyl group having 1 to 5 carbon atoms, particularly 1 to 3 carbon atoms.

[0399] The CTFE polymer may preferably be a CTFE homopolymer, or a copolymer comprising (1) CTFE, (2) one or more fluoroolefins other than CTFE having 2 to 8 carbon atoms, particularly TFE or HFP, and (3) a perfluoro(alkyl vinyl ether) having an alkyl group having 1 to 5 carbon atoms, particularly 1 to 3 carbon atoms.

[0400] The CTFE polymer may also be a copolymer of CTFE and one or more fluorine-free monomers, and examples of the fluorine-free monomers include alkenes such as ethylene and propylene; vinyl esters; vinyl ethers, etc.

[0401] In the manufacturing method of the present disclosure, for example, (I) as a non-melt-processable fluororesin, tetrafluoroethylene polymer [TFE polymer (PTFE)]; (II) as a 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 a fluororubber, TFE / P Polyethylene copolymers, TFE / propylene / third monomer copolymers (where the third monomer is VDF, HFP, CTFE, fluoroalkyl vinyl ethers, etc.), copolymers consisting of TFE and fluoroalkyl vinyl ethers; HFP / ethylene copolymers, HFP / ethylene / TFE copolymers; VDF / HFP copolymers, HFP / ethylene copolymers, VDF / TFE / HFP copolymers; and fluorine-containing segmented polymers described in Japanese Patent Publication No. 61-49327 can be suitably produced.

[0402] The above-mentioned fluoropolymers may be glassy, ​​plastic, or elastomeric. These may be amorphous or partially crystalline and can be subjected to compression firing, melting, or non-melting processes.

[0403] The fluorine substitution rate of the fluoropolymer, calculated by the following formula, is preferably 50% or more, more preferably 55% or more, even more preferably 60% or more, still more preferably 75% or more, and particularly preferably 80% or more. The fluorine substitution rate of the fluoropolymer is most preferably 90 to 100%.

[0404] As the fluoropolymer mentioned above, fluororesins are preferred, and among them, fluororesins with a fluorine substitution rate of 50% or more calculated by the following formula are more preferred, fluororesins with a fluorine substitution rate exceeding 50% are even more preferred, fluororesins with a fluorine substitution rate of 55% or more are even more preferred, fluororesins with a fluorine substitution rate of 60% or more are even more preferred, fluororesins with a fluorine substitution rate of 75% or more are even more preferred, fluororesins with a fluorine substitution rate of 80% or more are particularly preferred, and fluororesins with a fluorine substitution rate of 90 to 100%, i.e., perfluororesins, are most preferred.

[0405] (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 and chlorine atoms bonded to carbon atoms constituting the fluoropolymer)) × 100

[0406] As the perfluororesin mentioned above, a fluororesin with a fluorine substitution rate of 95 to 100% is more preferred, polytetrafluoroethylene (PTFE), FEP, or PFA is even more preferred, and PTFE is even more preferred.

[0407] The above-mentioned fluoropolymer may have a core-shell structure. Examples of fluoropolymers having a core-shell structure include modified PTFE, which contains 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 the PTFE described in Japanese Patent Publication No. 2005-527652.

[0408] The above core-shell structure can take the following forms: 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

[0409] In the fluoropolymer having the above-described core-shell structure, the lower limit of the core ratio is preferably 0.5% by mass, more preferably 1.0% by mass, even more preferably 2.0% by mass, even more preferably 3.0% by mass, particularly preferably 5.0% by mass, and most preferably 10.0% by mass. The upper limit of the core ratio is preferably 99.5% by mass, more preferably 99.0% by mass, even 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.

[0410] In the fluoropolymer having the above-described core-shell structure, the lower limit of the shell ratio is preferably 0.5% by mass, more preferably 1.0% by mass, even more preferably 2.0% by mass, even more preferably 3.0% by mass, particularly preferably 5.0% by mass, and most preferably 10.0% by mass. The upper limit of the shell ratio is preferably 99.5% by mass, more preferably 99.0% by mass, even 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.

[0411] PTFE can be produced by polymerizing at least TFE as a fluoromonomer. Various known modified monomers can also be used in combination in the production of PTFE. In this disclosure, PTFE is a concept that includes not only TFE homopolymers but also copolymers of TFE and modified monomers (hereinafter referred to as "modified PTFE").

[0412] The above-mentioned modified monomers are not particularly limited as long as they can copolymerize with TFE, and include fluoromonomers and non-fluoromonomers. Furthermore, one or more modified monomers may be used.

[0413] The non-fluoro monomer is not particularly limited, and the general formula is CH ２ =CR Ｑ１ -LR Ｑ２ (In the formula, R Ｑ１ represents a hydrogen atom or alkyl group. L represents a single bond, -CO-O-*, -O-CO-*, or -O-. * is R Ｑ２ Represents the connection position with R.Ｑ２ Examples of monomers represented by ) are: (where represents a hydrogen atom, an alkyl group, or a nitrile group.)

[0414] Examples of nonfluoro monomers 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, and cyclohexyl vinyl ether. Among these, butyl methacrylate, vinyl acetate, and acrylic acid are preferred as nonfluoro monomers.

[0415] Examples of fluoromonomers include perfluoroolefins such as hexafluoropropylene [HFP]; hydrogen-containing fluoroolefins such as trifluoroethylene and vinylidene fluoride [VDF]; perhaloolefins such as chlorotrifluoroethylene; perfluorovinyl ethers; (perfluoroalkyl)ethylenes; and perfluoroallyl ethers.

[0416] From the viewpoint of reactivity with TFE, the above 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.

[0417] In the production of the above TFE polymer, persulfates (e.g., ammonium persulfate) or organic peroxides such as disuccinic acid peroxide and diglutaric acid peroxide can be used as polymerization initiators, either alone or in mixtures thereof. They may also be used in combination with a reducing agent such as sodium sulfite to form a redox system. Furthermore, during polymerization, radical scavengers such as hydroquinone and catechol, or peroxide decomposition agents such as ammonium sulfite, can be added to adjust the radical concentration in the system.

[0418] As the above redox polymerization initiator, it is preferable to use a redox initiator that combines an oxidizing agent and a reducing agent. Examples of oxidizing agents include persulfates, organic peroxides, potassium permanganate, manganese triacetate, and ammonium cerium nitrate. Examples of reducing agents include sulfites, bisulfites, bromates, diimines, and oxalic acid. Examples of persulfates include ammonium persulfate and potassium persulfate. Examples of sulfites include sodium sulfite and ammonium sulfite. To increase the decomposition rate of the initiator, it is also preferable to add copper salts and iron salts to the redox initiator combination. Examples of copper salts include copper(II) sulfate, and examples of iron salts include iron(II) sulfate.

[0419] Examples of the redox initiators mentioned above include potassium permanganate / oxalic acid, potassium permanganate / ammonium oxalate, ammonium persulfate / bisulfite / ferrous sulfate, manganese triacetate / oxalic acid, cerium ammonium nitrate / oxalic acid, bromate / bisulfite, etc., with potassium permanganate / oxalic acid being preferred. When using a redox initiator, either an oxidizing agent or a reducing agent may be charged into the polymerization tank beforehand, and then the other may be added continuously or intermittently to initiate polymerization. For example, when using potassium permanganate / oxalic acid, it is preferable to charge oxalic acid into the polymerization tank and then continuously add potassium permanganate thereto.

[0420] In the production of the TFE polymer described above, known chain transfer agents can be used, but examples include saturated hydrocarbons such as methane, ethane, propane, and butane; halogenated hydrocarbons such as chloromethane, dichloromethane, and difluoroethane; alcohols such as methanol, ethanol, and isopropanol; and hydrogen. However, those in a gaseous state at room temperature and pressure are preferred.

[0421] In the production of the TFE polymer described above, a saturated hydrocarbon having 12 or more carbon atoms that is substantially inert to the reaction and becomes liquid under the above reaction conditions may be used in amounts of 2 to 10 parts by mass per 100 parts by mass of aqueous medium as a dispersion stabilizer for the reaction system. In addition, ammonium carbonate, ammonium phosphate, etc. may be added as a buffering agent to adjust the pH during the reaction.

[0422] When the polymerization of TFE is complete, an aqueous dispersion can be obtained with a solid content concentration of 1.0 to 50% by mass and an average primary particle diameter of 50 to 500 nm. The lower limit of the solid content concentration is preferably 5% by mass, and 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 average primary particle diameter is preferably 100 nm, and more preferably 150 nm. The upper limit is preferably 400 nm, and more preferably 350 nm.

[0423] Fine powder can be produced by coagulating an aqueous dispersion of TFE polymer. The aqueous dispersion of TFE polymer can be used as fine powder for various applications after coagulation, washing, and drying. When coagulating the aqueous dispersion of TFE polymer, the aqueous dispersion obtained by polymerization of polymer latex, etc., is usually diluted with water to a polymer concentration of 5 to 20% by mass, and if necessary, the pH is adjusted to neutral or alkaline, and then the mixture is stirred more vigorously than during the reaction in a container equipped with a stirrer. The coagulation may also be carried out while stirring with the addition of water-soluble organic compounds such as methanol and acetone, inorganic salts such as potassium nitrate and ammonium carbonate, or inorganic acids such as hydrochloric acid, sulfuric acid, and nitric acid as coagulants. The coagulation may also be carried out continuously using an in-line mixer or the like.

[0424] The concentration of the uncoagulated TFE polymer in the wastewater resulting from the above-mentioned coagulation is preferably low from the viewpoint of productivity, more preferably less than 0.4% by mass, and particularly preferably less than 0.3% by mass.

[0425] The manufacturing method disclosed herein can also be used to produce low molecular weight PTFE.

[0426] Low molecular weight PTFE (also called PTFE micropowder) with a molecular weight of 600,000 or less has excellent chemical stability, extremely low surface energy, and is less prone to fibrillation. Therefore, it is suitable as an additive for the manufacture of plastics, inks, cosmetics, paints, greases, office automation equipment components, toners, etc., for purposes such as improving slipperiness and the texture of the coating surface (see, for example, Japanese Patent Publication No. 10-147617).

[0427] When using the low molecular weight PTFE obtained by the above polymerization as a powder, the above aqueous dispersion can be coagulated to form powder particles.

[0428] The manufacturing method of this disclosure can also produce high molecular weight PTFE as PTFE. In this disclosure, high molecular weight PTFE means PTFE that is non-melt processable. In one embodiment, high molecular weight PTFE has non-melt processability and fibrillation properties. On the other hand, low molecular weight PTFE means PTFE that is melt processable. In one embodiment, low molecular weight PTFE has melt processability and does not have fibrillation properties.

[0429] The above-mentioned non-melt processability refers to 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.

[0430] The presence or absence of fibrillation properties can be determined by "paste extrusion," a typical method for molding "high molecular weight PTFE powder," which is a powder made from a polymer of TFE. Paste extrusion is usually 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 it has 0% elongation and breaks when pulled, it can be considered that it does not have fibrillation properties.

[0431] 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 using a sample molded in accordance with ASTM D4895-89 and measured by the water displacement method in accordance with ASTM D 792. In this disclosure, "high molecular weight" means that the above standard specific gravity is within the above range.

[0432] The above low molecular weight PTFE has a melt viscosity of 1 × 10⁻⁶ at 380°C. ２ ~7 x 10 ５ The molecular weight is Pa·s. In this disclosure, "low molecular weight" means that the 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, by preheating a 2g sample at 380°C for 5 minutes and maintaining it at the above temperature under a load of 0.7 MPa.

[0433] The high molecular weight PTFE described above has an extremely high melt viscosity compared to the low molecular weight PTFE described above, making it difficult to accurately measure its melt viscosity. On the other hand, while the melt viscosity of the low molecular weight PTFE can be measured, it is difficult to obtain molded articles from the low molecular weight PTFE that can be used to measure standard specific gravity, making it difficult to accurately measure its standard specific gravity. Therefore, in this disclosure, standard specific gravity is used as an indicator of the molecular weight of the high molecular weight PTFE, and melt viscosity is used as an indicator of the molecular weight of the low molecular weight PTFE. It should be noted that no measurement method is known that can directly determine the molecular weight of either the high molecular weight PTFE or the low molecular weight PTFE.

[0434] The high molecular weight PTFE described above preferably has a peak temperature of 333 to 347°C, and more preferably 335 to 345°C. The low molecular weight PTFE described above preferably has a peak temperature of 322 to 333°C, and more preferably 324 to 332°C. The peak temperature can be determined by using a differential scanning calorimeter (DSC) to heat PTFE that has not been previously heated to a temperature of 300°C or higher at a rate of 10°C / min, and the temperature corresponding to the maximum value appearing in the heat of fusion curve obtained.

[0435] The peak temperature of PTFE may be between 322 and 347°C. When PTFE is high molecular weight PTFE, the upper limit of the peak temperature of PTFE may be 347°C or less, 346°C or less, 345°C or less, 344°C or less, 343°C or less, 342°C or less, 341°C or less, or 340°C or less. When PTFE is high molecular weight PTFE, the lower limit of the peak temperature of PTFE may be 333°C or higher or 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 or 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 or 324°C or higher.

[0436] The average primary particle diameter of the low molecular weight PTFE primary particles is preferably 10 to 350 nm, more preferably 100 nm or more, even more preferably 150 nm or more, more preferably 400 nm or less, and even more preferably 350 nm or less.

[0437] The above high molecular weight PTFE is preferably such that, when PTFE that has not been heated to a temperature of 300°C or higher is heated at a rate of 10°C / min using a differential scanning calorimeter (DSC), at least one endothermic peak appears in the range of 333 to 347°C in the heat of fusion curve, and the heat of fusion amount at 290 to 350°C calculated from the above heat of fusion curve is 52 mJ / mg or more. The heat of fusion amount of the PTFE is more preferably 55 mJ / mg or more, and even more preferably 58 mJ / mg or more.

[0438] The manufacturing method of the present disclosure can also be used to produce TFE / HFP copolymer (FEP). The preferred monomer composition (mass%) of FEP is TFE:HFP = (60-95):(5-40), more preferably (85-92):(8-15).

[0439] 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 (excluding TFE and HFP) and fluorine-free monomers mentioned above. One or more types of other monomers can be used. Perfluoro(alkyl vinyl ether) is preferred as the other monomer. The content of other monomer units in FEP may be 0.1 to 2% by mass relative to the total monomer units.

[0440] TFE / perfluoro(alkyl vinyl ether) copolymer (PFA) can also be produced by the manufacturing method disclosed herein. The preferred monomer composition (mol%) of the TFE / perfluoro(alkyl vinyl ether) copolymer is TFE:perfluoro(alkyl vinyl ether) = (90-99.7):(0.3-10), more preferably (97-99):(1-3). The perfluoro(alkyl vinyl ether) is of the formula: CF ２ = CFORF ４ (wherein, Rf ４ It is preferable to use a perfluoroalkyl group having 1 to 6 carbon atoms.

[0441] In addition to TFE and perfluoro(alkyl vinyl ether), a copolymer of TFE, perfluoro(alkyl vinyl ether), and other monomers copolymerized with these monomers may be obtained as a TFE / perfluoro(alkyl vinyl ether) copolymer. Examples of other monomers include the fluorine-containing monomers (excluding TFE and perfluoro(alkyl vinyl ether)) and fluorine-free monomers mentioned above. One or more types 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 relative to the total monomer units.

[0442] 2. Fluoropolymers Also, this disclosure relates to general formula (12): [H-(CF ２ ) ｍ－１ CO ２ － ] M ＋ (In the formula, m is 12, M ＋ The term ∫ represents a cation. The term also relates to fluoropolymers that substantially do not contain compounds represented by ∫, or extractable organofluorine compounds (EOFs), and whose color L* value of test specimens prepared in accordance with ASTM D4895-89 is 50 or higher, which contain functional groups and have an average primary particle diameter of 500 nm or less.

[0443] (Fluorine-containing compounds having hydrophilic groups) In one embodiment, the fluoropolymer of the present disclosure substantially does not contain fluorine-containing compounds having hydrophilic groups, such as the compound represented by general formula (12).

[0444] In this disclosure, "substantially free of hydrophilic fluorine-containing compounds" means that the content of hydrophilic fluorine-containing compounds in the fluoropolymer is 10 ppm by mass or less, preferably 1 ppm by mass or less, more preferably 100 ppb by mass or less, even more preferably 10 ppb by mass or less, even more preferably 1 ppb by mass or less, and particularly preferably below the limit of quantification as measured by liquid chromatography-mass spectrometry (LC / MS).

[0445] Furthermore, the content of the fluorine-containing compound having a hydrophilic group in the fluoropolymer may be less than 500 ppb by mass and may be greater than 0 ppb by mass. The content of the fluorine-containing compound having a hydrophilic group in the fluoropolymer may be 100 ppb by mass or less, 50 ppb by mass or less, 25 ppb by mass or less, 20 ppb by mass or less, 10 ppb by mass or less, less than 5 ppb by mass, 3 ppb by mass or less, or 1 ppb by mass or less relative to the fluoropolymer. Most preferably, the content of the fluorine-containing compound having a hydrophilic group is below the limit of quantification as measured by liquid chromatography-mass spectrometry (LC / MS).

[0446] The hydrophilic group may be anionic, acidic, or acid-base. Examples of hydrophilic groups 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 , optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium, R ７ｙ ) is H or an organic group, and may be the same or different. Any two may bond to each other to form a ring. ) are examples of the above hydrophilic group, among others, -PO ３ M, -OPO ３ M, -SO ３ M, -OSO ３ M or -COOM is preferred, and -SO ３ M or -COOM is more preferred, and -COOM is even more preferred. ７ｙ Alkyl groups are preferred as the organic groups in R. ７ｙ For example, H or C １－１０ The organic group is preferably H or C １－４ The organic group is more preferably H or C １－４ A alkyl group is even more preferred.

[0447] Examples of the above-mentioned metal atoms include monovalent and divalent metal atoms, such as alkali metals (Group 1) and alkaline earth metals (Group 2), with Na, K, or Li being preferred.

[0448] Examples of fluorine-containing compounds having hydrophilic groups include those described above as fluorine-containing anionic surfactants. Typical compounds as fluorine-containing anionic surfactants are fluorine-containing anionic surfactants with a molecular weight of 1000 g / mol or less, preferably 800 g / mol or less.

[0449] In one embodiment of the fluoropolymer, the compound represented by the following general formula (1) is substantially not included as a fluorine-containing compound having a hydrophilic group. General formula (1): [X-Rf-A － ] ｉ M ｉ＋ (wherein X is H, Cl, Br, F or I, Rf is a partially fluorinated or fully fluorinated aliphatic group of a linear or branched chain, or a partially fluorinated or fully fluorinated aliphatic group of a linear or branched chain interrupted by at least one oxygen atom, A － is an acid group, M ｉ＋ (where i is a cation with a valency i, and i is an integer from 1 to 3.)

[0450] In one embodiment of the fluoropolymer, the fluorine-containing compound having a hydrophilic group is substantially free of the compound represented by the following general formula (2): General formula (2): [C ｎ－１ F ２ｎ－１ COO － ] M ＋ (In the formula, n is an integer from 9 to 14, M ＋ (This represents a cation.)

[0451] Compounds represented by general formula (2) (perfluoroalkanoic acid) are known to be formed during polymerization when perfluoroalkyl vinyl ethers or the like are used as modified monomers (see International Publication No. 2019 / 161153).

[0452] In one embodiment of the fluoropolymer, the fluorine-containing compound having a hydrophilic group is substantially free of the compound represented by the following general formula (3): General formula (3): [R １ -O-L-CO ２ － ] M ＋ (In the formula, R １L is a partially fluorinated or fully fluorinated aliphatic group of a linear or branched chain, or a partially fluorinated or fully fluorinated aliphatic group of a linear or branched chain interrupted by at least one oxygen atom, L is a non-fluorinated, partially fluorinated or fully fluorinated alkylene group of a linear or branched chain, M ＋ (This represents a cation.)

[0453] In one embodiment of the fluoropolymer, the fluorine-containing compound having a hydrophilic group is substantially free of the compound represented by general formula (4). General formula (4): [H-(CF ２ ) ｍ－１ CO ２ － ] M ＋ (In the formula, m is an integer from 4 to 20, M ＋ (This represents a cation.)

[0454] In one embodiment of the fluoropolymer, the compound represented by general formula (5) is substantially not contained as a fluorine-containing compound having a hydrophilic group. General formula (5): [H-(CF ２ ) ｎ SO ３ － ] M ＋ (In the formula, n is an integer from 4 to 20, M ＋ (This represents a cation.)

[0455] In one embodiment of the fluoropolymer, the fluorine-containing compound having a hydrophilic group substantially does not contain the compound represented by general formula (6). General formula (6): M ＋ [ － OOC-(CFX) ｎ－２ - COO － ] M ＋ (In the formula, n is an integer from 8 to 21, M ＋ X is a cation, and X is F, CF, and F are independent in each occurrence. ３ OCF ３ or OC ３ F ７ (This represents...)

[0456] In this disclosure, "substantially free of any of the compounds represented by general formulas (1) to (6)" means that the content of any of the compounds represented by general formulas (1) to (6) in the fluoropolymer is less than 500 ppb by mass relative to the fluoropolymer. The content of any of the compounds represented by general formulas (1) to (6) in the fluoropolymer may be 100 ppb by mass or less, 50 ppb by mass or less, 25 ppb by mass or less, 10 ppb by mass or less, less than 5 ppb by mass, or 1 ppb by mass or less relative to the fluoropolymer. Most preferably, the above content is below the limit of quantification as measured by liquid chromatography-mass spectrometry (LC / MS).

[0457] As a cation, H ＋ Examples include ammonium ions, alkali metal ions, and alkaline earth metal ions.

[0458] In one embodiment, the content of the compound represented by the following general formula (12) in the fluoropolymer is less than 500 ppb by mass relative to the fluoropolymer. General formula (12): [H-(CF ２ ) ｍ－１ CO ２ － ] M ＋ (In the formula, m is 12, M ＋ (This represents a cation.)

[0459] The content of the compound represented by general formula (12) may be 100 ppb by mass or less, 50 ppb by mass or less, 25 ppb by mass or less, 10 ppb by mass or less, less than 5 ppb by mass, or 1 ppb by mass or less, relative to the fluoropolymer. Most preferably, the above content is below the limit of quantification as measured by liquid chromatography-mass spectrometry (LC / MS).

[0460] In one embodiment, the total content of the compound represented by general formula (6-18-1) and the compound represented by general formula (6-18-2) in the fluoropolymer is less than 500 ppb by mass relative to the fluoropolymer. General formula (6-18-1): M ＋ [ － OOC-(CF ２ ) １６ - COO－ ] M ＋ (In the formula, M ＋ (where represents a cation) General formula (6-18-2): M ＋ [ － OOC-(CF ２ ) １５ - (CF (OCF ３ )) １ - COO － ] M ＋ (In the formula, M ＋ represents a cation. -CF ２ - and -CF (OCF ３ The order of existence of the elements in the formula is arbitrary.

[0461] The total content of the compound represented by general formula (6-18-1) and the compound represented by general formula (6-18-2) may be 100 ppb by mass or less, 50 ppb by mass or less, 25 ppb by mass or less, 10 ppb by mass or less, less than 5 ppb by mass, or 1 ppb by mass or less, relative to the fluoropolymer. Most preferably, the above content is below the limit of quantification as measured by liquid chromatography-mass spectrometry (LC / MS).

[0462] (Extractable Organofluorine Compounds (EOFs)) In one embodiment, the fluoropolymer of the Disclosure substantially does not contain extractable organofluorine compounds (EOFs).

[0463] In this disclosure, "substantially free of extractable organofluorine compounds (EOFs)" means that the EOF content in the fluoropolymer is 10 ppm by mass or less. Preferably, the EOF content in the fluoropolymer is 7 ppm by mass or less, and more preferably 5 ppm by mass or less.

[0464] EOF is determined by extraction from fluoropolymers with organic solvents. Therefore, EOF is extracted from fluoropolymers with methanol, and the EOF content in the methanol extract is determined by liquid chromatography-mass spectrometry (LC / MS). For example, methanol is added to 10 g of fluoropolymer, ultrasonic extraction is performed at 60°C for 120 minutes, and the supernatant is filtered to obtain the extract. The obtained extract is concentrated by nitrogen purging as appropriate to obtain a concentrated extract. The obtained extract is divided into two parts. One part is burned in the combustion tube of the analyzer, and after absorbing the generated gas into the solution, a portion of the absorbent solution is analyzed by ion chromatography to obtain the total fluorine extract amount. The other part is dried, the dried material is redissolved in methanol, diluted with ultrapure water, and the solution treated with a solid-phase extraction cartridge is analyzed by ion chromatography. － A quantitative analysis is performed to determine the amount extracted from the sample and obtain the amount of inorganic fluorine extracted. The amount of organic fluorine extracted is subtracted from the total amount of fluorine extracted to determine the amount of extractable organofluorine compounds (EOF).

[0465] EOF can also be determined by the measurement methods described in International Publication No. 2019 / 215636, Japanese Patent Publication No. 2023-92802, and others.

[0466] It has been found that EOF (excipient of fluoropolymerization) can be produced in small amounts as a byproduct during the emulsion polymerization of fluoromonomers. In other words, fluoropolymers (or compositions containing fluoropolymers) obtained by emulsion polymerization may contain EOF even if EOF was not added during polymerization. For example, it is known to form during polymerization when perfluoroalkyl vinyl ethers are used as comonomers (see International Publication No. 2019 / 215636).

[0467] In one embodiment, EOF is a fluorinated acid or a salt thereof. In one embodiment, EOF is a perfluoroalkanoic acid or a perfluorosulfonic acid. In one embodiment, EOF is a perfluoroalkanoic acid or a perfluorosulfonic acid having 4 to 17 carbon atoms, preferably 7 to 12 carbon atoms.

[0468] In one embodiment, EOF is a compound represented by general formula (7). General formula (7): CF ３ - (CF ２ ) ｎ -Z-M (wherein n represents an integer from 4 to 17, more preferably an integer from 7 to 12, and Z is -COO) － , or -SO ３ － (This represents M, where M represents a cation.)

[0469] In general formula (7), n is preferably an integer from 7 to 12. As for the cation, H ＋ Examples include ammonium ions, alkali metal ions, and alkaline earth metal ions.

[0470] In one embodiment, EOF may be a fluorinated acid compound, and may be at least one selected from the group consisting of aliphatic linear fluorinated acid compounds, branched fluorinated acid compounds, and cyclic fluorinated acid compounds. In one embodiment, the number of carbon atoms in the fluorinated acid compound may be 2 or more, 3 or more, 4 or more, or 5 or more, and may be 25 or less, 20 or less, 15 or less, 14 or less, 13 or less, 12 or less, 11 or less, or 10 or less.

[0471] Fluorinated acidic compounds may contain at least one carboxylic acid moiety, at least one sulfonic acid moiety, at least one sulfate moiety, and / or at least one alcohol moiety. Fluorinated alcohols are acidic and are included in fluorinated acidic compounds.

[0472] Fluorinated acidic compounds include carboxylic acids (R ｆ -COOH), sulfonic acid (R ｆ -SO ３ H), sulfate (R ｆ -CH ２ -O-SO ３ － ), or alcohol (R ｆ -CH ２ OH), dicarboxylic acid (HOOC-R ｆ -COOH), disulfuric acid (HO ３ S-R ｆ -SO ３H) is included. In each formula, R ｆ This is a fluoroalkyl group or a fluoroalkylene group. ｆ The number of carbon atoms may be 2 or more, 3 or more, 4 or more, or 5 or more, and may be 25 or less, 20 or less, 15 or less, 14 or less, 13 or less, 12 or less, 11 or less, or 10 or less.

[0473] Examples of fluorinated acidic compounds include CF ３ COOH, CF ２ HCOOH, C ２ F ５ COOH, C ２ F ４ H-COOH, C ４ F ９ COOH, CF ３ -O-(CF ２ ) ３ -O-CF ２ COOH, C ３ F ７ -O-(CF(CF ３ ))-COOH, CF ３ SO ３ H, C ２ F ５ SO ３ H, HOOC-(CF ２ ) ｎ -CF ２ -SO ３ H C ２ F ４ H-SO ３ H, H(CF ２ -CF ２ ) ｘ - (CF ２ -CF (CF ３ )) ｙ - (CF ２ -CF ２ ) ｚ -CH ２ -O-SO ３ H, CF ３ -CH ２ OH, H(CF ２ -CF ２ ) ｘ - (CF ２ -CF (CF ３ )) ｙ - (CF ２-CF ２ ) ｚ -CH ２ OH, CF ３ -O-(CF ２ ) ３ -O-CFH-CF ２ COOH, CF ３ -O-(CF ２ ) ２ COOH, etc. are examples.

[0474] Fluorinated acidic compounds may also have 1 to 4 hydrogen and / or chlorine atoms in their molecule. Further examples are commercially available compounds known as OPA and ADONA (ammonium 4,8-dioxy-3H-perfluorononanoate).

[0475] (Color Tone L* Value) The color tone L* value of the fluoropolymer in this disclosure is 50 or higher. The color tone L* value may be 60 or higher, 70 or higher, 80 or higher, or 90 or higher, and may be 100 or lower.

[0476] The color tone L* value of the fluoropolymer can be easily adjusted to the above-described range by producing the fluoropolymer using the manufacturing method of the present disclosure. In conventional manufacturing methods, in which a non-degradable surfactant is added to an aqueous dispersion and brought into contact with an adsorbent, the resulting fluoropolymer has a small color tone L* value, making it impossible to obtain the fluoropolymer of the present disclosure.

[0477] The color tone L* value can be measured according to the measurement method in accordance with JIS Z8781-4:2013, using the test specimen and a color meter ZE6000 manufactured by Nippon Denshoku Industries Co., Ltd., after preparing a test specimen from a fluoropolymer in accordance with ASTM D4895-89.

[0478] (Functional Groups) The fluoropolymers of this disclosure include functional groups. Preferably, the functional group is at least one selected from the group consisting of carbonyl groups, hydroxyl groups, heterocyclic groups, and amino groups.

[0479] In this disclosure, "carbonyl group" refers to a carbon-2 valent group composed of a carbon-oxygen double bond, and is represented as -C(=O)-. Functional groups containing the above carbonyl group are not particularly limited and include, for example, carbonate group, carboxylic acid halide group (halogenoformyl group), formyl group, carboxyl group, ester bond (-C(=O)O-), acid anhydride bond (-C(=O)O-C(=O)-), isocyanate group, amide group, imide group (-C(=O)-NH-C(=O)-), urethane bond (-NH-C(=O)O-), carbamoyl group (NH ２ -C(=O)-), carbamoyloxy group (NH ２ -C(=O)O-), ureido group (NH ２ -C(=O)-NH-), oxamoyl group (NH ２ Examples include compounds that contain a carbonyl group as part of their chemical structure, such as -C(=O)-C(=O)-.

[0480] In amide groups, imide groups, urethane bonds, carbamoyl groups, carbamoyloxy groups, ureido groups, oxamoyl groups, etc., the hydrogen atom bonded to the nitrogen atom may be substituted with a hydrocarbon group such as an alkyl group.

[0481] If the fluoropolymer is a non-melt-processable fluororesin such as polytetrafluoroethylene, the number of fluorocarbonyl groups (-COF groups) in the non-melt-processable fluororesin is 10 carbon atoms. ６ Preferably, there are fewer than 30 per unit, more preferably 20 or fewer, and even more preferably 10 or fewer.

[0482] In one embodiment, the carbonyl group contained in the non-melt-processable fluororesin is a carbonyl group within a carboxylic acid group (-COOH group).

[0483] The number of carboxylic acid groups (-COOH groups) in fluoropolymers is 10 carbon atoms. ６ Each unit may contain 30 or more, preferably 50 or more, more preferably 100 or more, even more preferably 150 or more, and still more preferably 200 or more.

[0484] If the fluoropolymer is high molecular weight PTFE, the number of carboxylic acid groups (-COOH groups) in the high molecular weight PTFE is 10 carbon atoms. ６ Each unit may contain 30 or more, preferably 40 or more.

[0485] If the fluoropolymer is low molecular weight PTFE, the number of carboxylic acid groups (-COOH groups) in the low molecular weight PTFE is 10 carbon atoms. ６ Each unit may contain 30 or more, preferably 50 or more, more preferably 100 or more, even more preferably 150 or more, and still more preferably 200 or more.

[0486] The upper limit on the number of carboxylic acid groups (-COOH groups) in a fluoropolymer varies depending on the molecular weight of the fluoropolymer, but for example, if the number of carbon atoms is 10 ６ Each item may contain 500 or fewer units.

[0487] The number of carboxylic acid groups and fluorocarbonyl groups can be measured in accordance with the method for analyzing end groups described in Japanese Patent Publication No. 4-20507. Specifically, a fluoropolymer powder is pre-formed by hand pressing to create a film with a thickness of approximately 0.1 mm. The prepared film is subjected to infrared absorption spectroscopy. Infrared absorption spectroscopy is also performed on a fluoropolymer with completely fluorinated ends, prepared by contacting the fluoropolymer with fluorine gas, and the number of carboxylic acid groups or fluorocarbonyl groups is calculated from the difference spectrum of the two using the following formula: Number of carboxylic acid groups or fluorocarbonyl groups (10 carbon atoms) ６ Absorbance per unit = (l × K) / t l: absorbance K: correction factor t: film thickness (mm) The absorption frequency of the carboxylic acid group is 3560 cm⁻¹ －１ The correction factor is set to 440. The absorption frequency of the fluorocarbonyl group is 1883 cm⁻¹. －１ The correction factor will be 440.

[0488] If the fluoropolymer is a melt-processable fluororesin, the number of functional groups in the melt-processable fluororesin is 10 carbon atoms. ６The number of functional groups per unit is preferably 3 to 800. A more preferable lower limit is 15, an even more preferable lower limit is 30, and a particularly preferable lower limit is 50. From the viewpoint of productivity, the upper limit of the number of functional groups is more preferably 200.

[0489] The number of functional groups in a melt-processable fluoropolymer is calculated by compressing a film sheet with a thickness of 0.05 to 0.20 mm obtained by compression molding the powder of the melt-processable fluoropolymer at a molding temperature 50°C higher than its melting point and a molding pressure of 5 MPa. The infrared absorption spectrum of the film sheet is analyzed using an infrared spectrophotometer, and the type of characteristic absorption of the functional groups is determined by comparing it with the infrared absorption spectrum of a known film. The number of functional groups is then calculated from the difference spectra using the following formula.

[0490] Number of functional groups (10 carbon atoms) ６ (per unit) = (l × K) / t l: absorbance K: correction factor t: film thickness (mm) The correction factors for the functional groups in question are shown in Table 1.

[0491]

[0492] The correction coefficients in Table 1 are for carbon numbers of 10 ６ This value was determined from the infrared absorption spectrum of a model compound to calculate the number of functional groups per compound.

[0493] Functional groups can be introduced into fluoropolymers, for example, by using persulfates as polymerization initiators when polymerizing fluoromonomers.

[0494] (Average Primary Particle Diameter) The average primary particle diameter of the fluoropolymer of this disclosure is 500 nm or less, preferably 450 nm or less, more preferably 400 nm or less, even more preferably 350 nm or less, even more preferably 300 nm or less, particularly preferably 250 nm or less, preferably 10 nm or more, more preferably 100 nm or more, and even more preferably 150 nm or more. The average primary particle diameter of the fluoropolymer can be adjusted to the above range by producing the fluoropolymer using emulsion polymerization. When the fluoropolymer is produced by suspension polymerization, it is difficult to generate primary particles of the fluoropolymer, and therefore a fluoropolymer having an average primary particle diameter within the above range cannot be obtained.

[0495] The average primary particle diameter is the average particle diameter of primary particles dispersed in an aqueous dispersion, and is different from the average particle diameter of secondary particles (powder) formed by the aggregation of primary particles. The average primary particle diameter can be measured by dynamic light scattering. First, an aqueous dispersion is prepared with a polymer solid content concentration of approximately 1.0 mass%, and then measured using dynamic light scattering with a measurement temperature of 25°C, a refractive index of 1.3328 for the solvent (water), a viscosity of 0.8878 mPa·s for the solvent (water), and 70 cumulative measurements. For example, the ELSZ-1000S (manufactured by Otsuka Electronics Co., Ltd.) can be used for dynamic light scattering.

[0496] Furthermore, the average primary particle diameter can also be measured by the following method: Dilute the dispersion with water until the solid content concentration reaches 0.15% by mass. Measure the transmittance of 550 nm projection light per unit length of the resulting diluted latex, and the average particle diameter determined by measuring the directional diameter using a transmission electron microscope image, to create a calibration curve. Using this calibration curve, the average particle diameter can be determined from the measured transmittance of 550 nm projection light for each sample.

[0497] The fluoropolymers of this disclosure can be suitably produced by the manufacturing methods of this disclosure.

[0498] (Fluoropolymers and Compositions) The Disclosure also relates to compositions containing the fluoropolymers of the Disclosure. The form of the fluoropolymers of the Disclosure and the compositions of the Disclosure is not particularly limited, but may be, for example, aqueous dispersions, coagulations, dried products, powders, pellets, etc. An aqueous dispersion is a dispersion system in which an aqueous medium is the dispersion medium and the fluoropolymer is the dispersed phase. The aqueous medium is not particularly limited as long as it is a liquid containing water, and may contain, for example, an organic solvent such as alcohol, ether, ketone, or paraffin wax in addition to water.

[0499] The fluoropolymers and compositions of this disclosure may be aqueous fluoropolymer dispersions in which primary particles of the fluoropolymer are dispersed in an aqueous medium. The aqueous dispersion may be an aqueous dispersion obtained by the polymerization described above, a dispersion obtained by concentrating or stabilizing this aqueous dispersion, or a dispersion of fluoropolymer powder in an aqueous medium. The fluoropolymers and compositions of this disclosure may also be fluoropolymer powders. Fluoropolymer powders can be obtained, for example, by coagulating the fluoropolymer in the aqueous fluoropolymer dispersion using a known method.

[0500] The fluoropolymers of this disclosure and the fluoropolymers in the compositions may have a similar structure to the fluoropolymers obtained by the manufacturing methods of this disclosure. Therefore, examples of fluoropolymers include tetrafluoroethylene polymers [TFE polymers (PTFE)], melt-processable fluororesins, and fluororubbers.

[0501] The fluoropolymer may be a polymer that is non-melt processable or a polymer that is melt processable. A non-melt processable fluororesin or a melt processable fluororesin is preferred as the fluoropolymer.

[0502] The fluorine substitution rate of the fluoropolymer is preferably 50% or more, more preferably 55% or more, even more preferably 60% or more, still more preferably 75% or more, and particularly preferably 80% or more. The fluorine substitution rate of the fluoropolymer is most preferably 90 to 100%.

[0503] As the fluoropolymer mentioned above, fluororesins are preferred, and among them, fluororesins with a fluorine substitution rate of 50% or more calculated by the following formula are more preferred, fluororesins with a fluorine substitution rate exceeding 50% are even more preferred, fluororesins with a fluorine substitution rate of 55% or more are even more preferred, fluororesins with a fluorine substitution rate of 60% or more are even more preferred, fluororesins with a fluorine substitution rate of 75% or more are even more preferred, fluororesins with a fluorine substitution rate of 80% or more are particularly preferred, and fluororesins with a fluorine substitution rate of 90 to 100%, i.e., perfluororesins, are most preferred.

[0504] (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 and chlorine atoms bonded to carbon atoms constituting the fluoropolymer)) × 100

[0505] As the perfluororesin mentioned above, a fluororesin with a fluorine substitution rate of 95 to 100% is more preferred, PTFE, FEP, or PFA are even more preferred, and PTFE is even more preferred.

[0506] The fluoropolymers and compositions of this disclosure can be suitably used for the applications described above. Furthermore, the fluoropolymers and compositions of this disclosure can be suitably used as raw materials (molding materials) for applications such as wire coatings, tubes, and stretched films.

[0507] Although embodiments have been described above, it should be understood that various modifications to the form and details are possible without departing from the spirit and scope of the claims.

[0508] <1> According to the first aspect of this disclosure, a method for producing a fluoropolymer is provided, comprising: preparing an aqueous dispersion containing a fluoropolymer by emulsion polymerization of a fluoromonomer; adding a degradable surfactant to the aqueous dispersion; contacting the aqueous dispersion containing the degradable surfactant with an adsorbent; then removing the adsorbent to recover the aqueous dispersion that has been in contact with the adsorbent; coagulating the fluoropolymer in the recovered aqueous dispersion; and drying the resulting coagulation to obtain the fluoropolymer. <2> According to the second aspect of this disclosure, a method for producing a fluoropolymer according to the first aspect is provided, wherein the degradable surfactant is at least one selected from the group consisting of acid hydrolyzable surfactants, basic hydrolyzable surfactants, enzymatically degradable surfactants, and thermally degradable surfactants. <3> According to the third aspect of this disclosure, a method for producing a fluoropolymer according to the first or second aspect is provided, wherein the degradable surfactant is at least one selected from the group consisting of acid hydrolyzable surfactants and thermally degradable surfactants. <4> According to a fourth aspect of this disclosure, a method for producing a biodegradable surfactant is provided according to any one of the first to third aspects, wherein the biodegradable surfactant is at least one selected from the group consisting of biodegradable nonionic surfactants and biodegradable amphoteric surfactants. <5> According to a fifth aspect of this disclosure, a method for producing a biodegradable surfactant is provided according to any one of the first to fourth aspects, wherein the biodegradable surfactant is a biodegradable nonionic surfactant containing at least one Si. <6> According to a sixth aspect of this disclosure, a method for producing a biodegradable surfactant is provided according to any one of the first to fifth aspects, wherein the biodegradable surfactant is a biodegradable nonionic surfactant having a siloxane bond. <7> According to a seventh aspect of this disclosure, a method for producing a biodegradable surfactant is provided according to a first or second aspect, wherein the biodegradable surfactant is alkyldimethylamine oxide. <8> According to an eighth aspect of this disclosure, a method for producing a biodegradable surfactant is provided according to a first or second aspect, wherein the biodegradable surfactant is cellulose. <9> According to the ninth aspect of this disclosure, a manufacturing method according to any of the first to eighth aspects is provided, wherein the amount of the degradable surfactant used is 0.1% by mass or more with respect to the mass of the fluoropolymer in the aqueous dispersion.<10> According to the tenth aspect of the present disclosure, a method for producing the adsorbent according to any one of the first to ninth aspects is provided, wherein the adsorbent is at least one selected from the group consisting of ion exchange resin, synthetic adsorbent, silica gel, polymer adsorbent, activated carbon, diatomaceous earth, and zeolite. <11> According to the eleventh aspect of the present disclosure, a method for producing the adsorbent according to any one of the first to tenth aspects is provided, wherein the adsorbent is an anion exchange resin. <12> According to the twelfth aspect of this disclosure, a first or second method for producing the fluoropolymer is provided, comprising: (1) preparing an aqueous dispersion (1) containing a fluoropolymer by emulsion polymerization of a fluoromonomer; (2) preparing an aqueous dispersion (2) containing the acid hydrolyzable surfactant and having a pH greater than 4.5 by adding an acid hydrolyzable surfactant to the aqueous dispersion (1); (3) recovering an aqueous dispersion (3) by contacting the aqueous dispersion (2) with an adsorbent and then removing the adsorbent; (4) adjusting the pH of the aqueous dispersion (3) to 4.5 or less by adding an acid and stirring the aqueous dispersion (3) to coagulate the fluoropolymer in the aqueous dispersion (3) and recovering the coagulated product; and (5) drying the coagulated product. <13> According to the thirteenth aspect of this disclosure, the aqueous dispersion (1) is a product of the general formula (12): [H-(CF. ２ ) ｍ－１ CO ２ － ] M ＋ (In the formula, m is 12, M ＋ A method for producing a compound according to the 12th aspect of this disclosure is provided, further comprising at least one selected from the group consisting of a compound represented by (where represents a cation) and an extractable organofluorine compound (EOF). <14> According to the 14th aspect of this disclosure, a method for producing a compound according to any of the first to 13 aspects is provided, wherein the fluoropolymer is polytetrafluoroethylene. <15> According to the 15th aspect of this disclosure, General formula (12): [H-(CF ２ ) ｍ－１ CO ２ － ] M ＋ (In the formula, m is 12, M ＋A fluoropolymer is provided which is substantially free of compounds represented by (where represents a cation) and extractable organofluorine compounds (EOFs), has a color tone L* value of 50 or higher for test specimens prepared in accordance with ASTM D4895-89, contains functional groups, and has an average primary particle diameter of 500 nm or less. <16> According to the sixteenth aspect of this disclosure, a fluoropolymer according to the fifteenth aspect is provided which is a powder of polytetrafluoroethylene.

[0509] Next, embodiments of the present disclosure will be described with reference to examples, but the present disclosure is not limited to such embodiments.

[0510] Each value in the examples was measured by the following method.

[0511] <PTFE Solid Content Concentration (Content) in Aqueous Dispersion> The PTFE solid content concentration (P mass%) in the aqueous dispersion was calculated using the formula: P = [Z / X] × 100 (mass%) from the residual amount (Yg) obtained by heating approximately 1g (Xg) of the sample in a 5cm diameter aluminum cup at 110°C for 30 minutes, and then heating the resulting residual amount (Zg) obtained by heating the Yg at 300°C for 30 minutes.

[0512] <Average Primary Particle Size> The aqueous dispersion was diluted with water until the solid content concentration was 0.15% by mass. A calibration curve was created by measuring the transmittance of 550 nm projected light per unit length of the resulting diluted latex and the average primary particle size determined by measuring the directional diameter using transmission electron microscopy. Using this calibration curve, the average primary particle size was determined from the measured transmittance of 550 nm projected light for each sample.

[0513] <Standard Specific Gravity (SSG)> Samples molded in accordance with ASTM D4895-89 were used, and the SSG was measured by the water displacement method in accordance with ASTM D-792.

[0514] <Melting Point (Peak Temperature)> For the PTFE powder obtained in the examples, a differential scanning calorimeter (DSC) was used to plot a heat of fusion curve at a heating rate of 10°C / min. The temperature corresponding to the maximum value of the endothermic peak appearing in the heat of fusion curve was defined as the melting point of PTFE.

[0515] <Number of Functional Groups> The PTFE powder obtained in the examples was pre-formed by hand pressing to create a film with a thickness of approximately 0.1 mm. Using the obtained film, infrared absorption spectroscopy analysis was performed using the method described above to calculate the number of carbonyl groups (number of carboxylic acid groups and number of fluorocarbonyl groups).

[0516] <General formula (4): [H-(CF ２ ) ｍ－１ CO ２ － ] M ＋ Measurement of the compound content indicated by > The content was measured using liquid chromatography-mass spectrometry under the following conditions.

[0517] Extraction from PTFE powder: 1 g of PTFE powder was mixed with 7.9 g (10.0 mL) of methanol, and sonication was performed at 60°C for 120 minutes. The supernatant containing the compound represented by general formula (4) was extracted. The obtained extract was concentrated by purging with nitrogen as appropriate to obtain a concentrated extract.

[0518] The content of the compound represented by general formula (4) in the extract was determined by converting it to perfluorooctanoic acid.

[0519] Calibration Curve for Perfluorooctanoic Acid Five levels of methanol standard solutions of perfluorooctanoic acid with known concentrations ranging from 1 ng / mL to 100 ng / mL were prepared and measured using a liquid chromatograph-mass spectrometer (Waters, LC-MS ACQUITY UPLC / TQD). Using a first-order approximation from the concentration of each sample and the integral value of the peak, a and b were determined using the following relationship (1): A = a × X + b (1) A: Peak area of ​​perfluorooctanoic acid X: Concentration of perfluorooctanoic acid (ng / mL)

[0520] Measurement equipment configuration and LC-MS measurement conditions

[0521] MRM measurement parameters

[0522] The content of compounds represented by general formula (4) with 12 carbon atoms in the extract was measured using a liquid chromatograph-mass spectrometer. The peak area of ​​each compound represented by general formula (4) with 12 carbon atoms was determined from the extracted liquid phase using the MRM method.

[0523] MRM measurement parameters

[0524] The content of the compound represented by general formula (4) for a number of carbon atoms in the extract was calculated using the following formula (3). a and b in formula (3) were obtained from formula (1). XCm = ((ACm - b) / a) × ((50 × (m - 1) + 45) / 413) (3) XCm: Content of the compound represented by general formula (4) for a number of carbon atoms in the extract (ng / mL) ACm: Peak area of ​​the compound represented by general formula (4) for a number of carbon atoms in the extract The limit of quantification in this measurement is 1 ng / mL.

[0525] Content of the compound represented by general formula (4) with several carbon atoms m contained in PTFE powder The content of the compound represented by general formula (4) with several carbon atoms m contained in PTFE powder was determined by the following formula (4): YCm = XCm × 10.0 (4) YCm: Content of the compound represented by general formula (4) with several carbon atoms m contained in PTFE powder (ppb vs PTFE) The limit of quantification is 10 mass ppb.

[0526] <General formula (6): M ＋ [ － OOC-(CFX) ｎ－２ - COO － ] M ＋ Measurement of the compound content indicated by > The content was measured using liquid chromatography-mass spectrometry under the following conditions.

[0527] Extraction from aqueous dispersion: 5.0 g of aqueous dispersion was weighed, 10 g of methanol was added, and the mixture was poured into a cylindrical filter paper. Soxhlet extraction was performed until the total amount of methanol used as the extraction solvent reached 150 g. The resulting extract was then diluted with methanol to a volume of 250 ml to obtain an extract containing the compound represented by general formula (6). The obtained extract was further concentrated by purging with nitrogen as appropriate to obtain a concentrated extract.

[0528] The content of the compound represented by general formula (6-18-1) in the extract was determined by converting it to dodecafluorosuberic acid.

[0529] Calibration Curve of Dodecafluorosveric Acid Five levels of methanol standard solutions of dodecafluorosveric acid with known concentrations ranging from 20 ng / mL to 500 ng / mL were prepared and measured using a liquid chromatograph-mass spectrometer (Waters, LC-MS ACQUITY UPLC / TQD). Using a first-order approximation from the integral values ​​of the peaks of each sample, a and b were determined using the following relationship (5): A = a × X + b (5) A: Peak area of ​​dodecafluorosveric acid X: Concentration of dodecafluorosveric acid (ng / mL)

[0530] Measurement equipment configuration and LC-MS measurement conditions

[0531] MRM measurement parameters

[0532] The content of the compound represented by general formula (6-18-1) in the extract was measured using a liquid chromatograph-mass spectrometer. The peak area of ​​the compound represented by general formula (6-18-1) was determined from the extracted liquid phase using the MRM method.

[0533] Among the compounds represented by general formula (6), the compound represented by general formula (6-18-1) was selected for measurement. General formula (6-18-1): M ＋ [ － OOC-(CF ２ ) １６ - COO － ] M ＋ (In the formula, M ＋ (This represents a cation.)

[0534] MRM measurement parameters

[0535] The content of the compound represented by general formula (6) in the extract was calculated using the following formula (6). a and b in formula (6) were obtained from formula (5). XCn = ((ACn - b) / a) × ((50 × c + 116 × d + 89) / 389) (6) XCn: Content of the compound represented by general formula (6) in the extract (ng / mL) ACn: Peak area of ​​the content of the compound represented by general formula (6) in the extract The limit of quantification in this measurement is 20 ng / mL.

[0536] Content of the compound represented by general formula (6) in the aqueous dispersion The content of the compound represented by general formula (6) in the aqueous dispersion was determined by the following formula (7): YCn = XCn × 50 (7) YCn: Content of the compound represented by general formula (6) in the aqueous dispersion (ppb vs. aqueous dispersion) The limit of quantification is 1000 ppb by mass.

[0537] The content of the compound represented by general formula (6-18-2) in the extract was determined by converting it to dodecafluorosuberic acid.

[0538] Calibration Curve of Dodecafluorosveric Acid Five levels of methanol standard solutions of dodecafluorosveric acid with known concentrations ranging from 20 ng / mL to 500 ng / mL were prepared and measured using a liquid chromatograph-mass spectrometer (Waters, LC-MS ACQUITY UPLC / TQD). Using a first-order approximation from the integral values ​​of the peaks of each sample, a and b were determined using the following relationship (5): A = a × X + b (5) A: Peak area of ​​dodecafluorosveric acid X: Concentration of dodecafluorosveric acid (ng / mL)

[0539] Measurement equipment configuration and LC-MS measurement conditions

[0540] SIM measurement parameters (SIM: Selected Ion Monitoring)

[0541] The content of the compound represented by general formula (6-18-2) in the extract was measured using a liquid chromatograph-mass spectrometer. The peak area of ​​the compound represented by general formula (6-18-2) was determined from the extracted liquid phase using the SIM method.

[0542] Among the compounds represented by general formula (6), the compound represented by general formula (6-18-2) was selected for measurement. General formula (6-18-2): M ＋ [ － OOC-(CF ２ ) １５ - (CF (OCF ３ )) １ - COO － ] M ＋ (In the formula, M ＋ represents a cation. -CF ２ - and -CF (OCF ３ The order of existence of the elements in the formula is arbitrary.

[0543] SIM measurement parameters

[0544] The content of the compound represented by general formula (6) in the extract was calculated using the following formula (6). a and b in formula (6) were obtained from formula (5). XCn = ((ACn - b) / a) × ((50 × c + 116 × d + 89) / 389) (6) XCn: Content of the compound represented by general formula (6) in the extract (ng / mL) ACn: Peak area of ​​the content of the compound represented by general formula (6) in the extract The limit of quantification in this measurement is 20 ng / mL.

[0545] Content of the compound represented by general formula (6) in the aqueous dispersion The content of the compound represented by general formula (6) in the aqueous dispersion was determined by the following formula (7): YCn = XCn × 50 (7) YCn: Content of the compound represented by general formula (6) in the aqueous dispersion (ppb vs. aqueous dispersion) The limit of quantification is 1000 ppb by mass.

[0546] <Color Tone L* Value> Test specimens were prepared from PTFE powder in accordance with ASTM D4895-89. The color tone was measured using a color meter ZE6000 manufactured by Nippon Denshoku Industries Co., Ltd., based on the measurement method in accordance with JIS Z8781-4:2013.

[0547] <Surface Tension of Degradable Surfactants> Surface tension was measured using the Wilhelmy method. An aqueous dispersion or aqueous solution containing 0.1% by mass of an acid hydrolyzable surfactant and having a pH of 7 was prepared, and its surface tension was measured. Then, the pH was adjusted to less than 3, and the surface tension was measured after being left at 25°C for 2 hours. The rate of change was calculated using the following formula: Rate of change of surface tension (%) = [(Surface tension of aqueous dispersion or aqueous solution after adjusting the pH to less than 3) - (Surface tension of aqueous dispersion or aqueous solution at pH 7)] / (Surface tension of aqueous dispersion or aqueous solution at pH 7) × 100

[0548] <Measurement of extractable organofluorine compounds (EOFs) content> The amount of extractable organofluorine compounds (EOFs) was determined by subtracting the amount of inorganic fluorine extracted from the total amount of fluorine extracted below.

[0549] 10 g of fluoropolymer extracted from PTFE powder was added to 500 mL of methanol, and ultrasonic extraction was performed at 60°C for 120 minutes. The supernatant was filtered to obtain the extract. The obtained extract was concentrated by nitrogen purging as appropriate to obtain a concentrated extract.

[0550] The total fluorine extract amount was measured by dividing the obtained extract into two parts. One part was burned in the combustion tube of the analyzer, and the generated gas was absorbed into the solution. A portion of the absorbent solution was then analyzed by ion chromatography to obtain the total fluorine extract amount.

[0551] The amount of inorganic fluorine extracted was measured. The extracted solution was divided into two parts, the other part was allowed to dry, this dry material was redissolved in methanol, diluted with ultrapure water, and the solution treated with a solid-phase extraction cartridge was subjected to ion chromatography. － Quantitative analysis was performed to determine the amount extracted from the sample, and the amount of inorganic fluorine extracted was obtained.

[0552] <Evaluation of Chargeability> 10 g of fluoropolymer was placed in a polyethylene bag and shaken five times by hand. Then, 6 g was weighed into a petri dish whose surface had been wiped with acetone. The surface potential of the fluoropolymer was measured using an electrostatic meter (ASPURE, YC-102), and the chargeability was evaluated according to the following criteria: ◎ Very good: -0.3 kV or more and 0 kV or less ○ Good: -0.5 kV or more and less than -0.3 kV △ Poor: -1.0 kV or more and less than -0.5 kV × Very poor: Less than -1.0 kV

[0553] <Charge Amount> The charge amount was measured in accordance with JIS C61340-2-2:2013, in an environment adjusted to room temperature of 25±2°C and humidity of 45±10%RH, using the following method. The PTFE powder for evaluation was left to stand in a SUS container for 24 hours or more. After that, the standing PTFE powder was transferred to a Faraday cage (Kasuga Electric Co., Ltd., KQ-1400), and the amount of charge per unit mass of powder (charge amount A) was measured using a coulomb meter (Kasuga Electric Co., Ltd., NK-1001A). Powders with a charge amount A between -1.0 and 0.0 nC / g were used for the test. 25 g of pre-treated PTFE powder was placed in a stainless steel container. Five stainless steel sieves (60 mm high, 200 mm in diameter) were stacked on top of the container, and the container was sandwiched between 1 mm thick rubber sheets. This was then set in a rotary tap sieve shaker (CMT Co., Ltd., model D-B), and while shaking at an amplitude of 28 mm and a shaking speed of 290 rpm, the container was tapped 10 times with a hammer weight of 2.2 kg and 156 tpm. Next, the stainless steel container was removed from the rotary tap sieve shaker, and the PTFE powder was transferred into a Faraday cage (Kasuga Electric Co., Ltd., KQ-1400). The amount of charge per unit mass of powder (charge amount B) was measured using a coulomb meter (Kasuga Electric Co., Ltd., NK-1001A). The charge amount was calculated using the following formula. Formula: Charge amount (nC / g) = Charge amount B (nC / g) - Charge amount A (nC / g) This operation was repeated 10 times, and the average value was taken as the charge amount of the PTFE powder.

[0554] The surfactants used in the experimental examples are as follows: Polyether-modified organosiloxane (trade name KP-110, manufactured by Shin-Etsu Chemical Co., Ltd.) Percentage change in surface tension = 147% Surface tension of a pH 7 and 0.1% by mass aqueous dispersion is 20.5 mN / m Surface tension of a pH 2.3 and 0.1% by mass aqueous dispersion after being left at 25°C for 2 hours is 50.6 mN / m Polyoxyethylene alkyl ether (trade name TDS-80, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) Percentage change = 0% Surface tension of a pH 7 and 0.1% by mass aqueous solution is 27.9 mN / m Surface tension of a pH 2.7 and 0.1% by mass aqueous solution after being left at 25°C for 2 hours is 27.9 mN / m Decyldimethylamine N-oxide (trade name Kadenax DM-10D-W, manufactured by Lion Specialty Chemicals) Percentage of residue after heating a 30% by mass aqueous solution (pH 7.0 or higher) at 160°C for 1 hour = 0% by mass

[0555] Polymerization Example 1 Following the method described in Example 7 of International Publication No. 2019 / 172382, the amount of surfactant aqueous solution C added was changed from 30 g to 14.3 g, and the amount of surfactant aqueous solution D added by the end of the reaction was changed from 27 g to 60 g to obtain PTFE aqueous dispersion 1. The solid content concentration of the obtained PTFE aqueous dispersion 1 was 26.5% by mass, and the average primary particle size was 224 nm.

[0556] Experimental Example 1 120 g of PTFE aqueous dispersion 1 obtained in polymerization example 1 was mixed with aqueous ammonia to adjust the pH to 7.0. Then, 1.6 g of the acid-degradable nonionic surfactant KP-110 was added. Next, 38.2 g of anion exchange resin (A400OH, manufactured by Purolite) was added and the mixture was stirred for 60 minutes at a strength that did not cause aggregation. Then, the anion exchange resin was removed using a mesh. The anion exchange resin was changed to Lewatit MonoPlus TP109 (manufactured by Lanxess), and this operation was repeated twice to obtain PTFE aqueous dispersion 2. The solid content concentration of PTFE aqueous dispersion 2 was 26.3%, and the pH was 8.9.

[0557] To 100 g of the obtained PTFE aqueous dispersion, 99.4 g of water was added, and 10% nitric acid was added to adjust the pH to 2.5. The mixture was then allowed to stand for 2 hours. Coagulation was then performed by high-speed stirring to obtain a wet polymer. The obtained wet polymer was dried at 160°C for 18 hours to obtain PTFE powder.

[0558] The peak temperature of the obtained PTFE powder measured by DSC was 342°C. Furthermore, the obtained PTFE powder contained the general formula (12): [H-(CF ２ ) ｍ－１ CO ２ － ] M ＋ (In the formula, m is 12, M ＋ The compound indicated by ) was below the limit of quantification. In accordance with ASTM D4895-89, the color L* value of the test specimen prepared from PTFE powder was 81.0.

[0559] Experimental Example 2 (Comparison) To 100 g of the aqueous PTFE dispersion obtained in Polymerization Example 1, 100.9 g of water was added, and 10% nitric acid was added to adjust the pH to 2.5. Then, coagulation was performed by high-speed stirring to obtain a wet polymer. The obtained wet polymer was dried at 160°C for 18 hours to obtain PTFE powder. General formula (12): [H-(CF ２ ) ｍ－１ CO ２ － ] M ＋ (In the formula, m is 12, M ＋ The compound indicated by (where represents a cation) had a concentration of 141 ppb by mass. The color L* value of the test specimen prepared from PTFE powder was 76.5 in accordance with ASTM D4895-89.

[0560] Experimental Example 3 (Comparison): The same procedure as in Experimental Example 1 was performed, except that KP-110 was replaced with TDS-80, but coagulation did not occur.

[0561] Polymerization Example 2 A SUS reactor with a stirrer and an internal volume of 6 L was charged with 180 g of paraffin, 0.011 g of 2-propanol as a chain transfer agent, 0.0021 g of A1315 (Harcross Chemicals, average molecular weight 860) as a nucleating agent, and 3500 g of deionized water, and then sealed. The reactor was then heated to 90°C while being suctioned and simultaneously purged with a TFE to remove oxygen from the reactor, and stirred at a speed of 260 rpm. 3.0 g of HFP was charged into the reactor and injected under pressure with a TFE until the pressure reached 0.78 MPaG. The reactor was kept at 90°C, the stirring speed was changed to 70 rpm, and then 0.36 g of APS dissolved in 10 g of deionized water was added, and the pressure in the reactor was increased to 0.83 MPaG with a TFE. One hour after adding APS, the pressure inside the reactor was 0.79 MPaG. 0.011 g of 2-propanol, 0.0021 g of A1315, and 0.358 g of APS were added again, and the reactor pressure was increased to 0.83 MPaG using TFE.

[0562] Two hours after the second addition of APS, the pressure inside the reactor was 0.80 MPaG. The reactor was evacuated to 0.10 MPaG. After another hour, the pressure inside the reactor was 0.10 MPaG. The reactor temperature was changed to 70°C, and the reactor was suctioned and simultaneously purged with TFE. The reactor temperature was maintained at 70°C, and 4 hours and 30 minutes after the initial addition of APS, the stirring speed was changed to 260 rpm, and 3.0 g of HFP was added, followed by 0.036 g of APS dissolved in 20 g of deionized water, and the reactor pressure was raised to 0.83 MPaG using TFE. The total amount of water added to the reactor was 3600 g.

[0563] A decrease in pressure was observed again, and thereafter TFE was added to the reactor to maintain a constant pressure of 0.78 MPaG. When the amount of TFE consumed in the reaction reached 180 g, the reactor was evacuated to 0.1 MPaG, and then the pressure was increased to 0.83 MPaG with TFE. Thereafter, the pressure was maintained at a constant 0.78 MPaG. When the amount of TFE consumed in the reaction reached approximately 900 g, the supply of TFE was stopped, stirring was stopped, and the reaction was terminated. Thereafter, the reactor was evacuated until the pressure returned to atmospheric pressure, the contents were removed from the reactor and cooled, the separated paraffin was removed, and PTFE aqueous dispersion 3 was obtained. No polymer adhesion to the reactor was observed.

[0564] The obtained PTFE aqueous dispersion 3 had a solid content concentration of 20.0% by mass and an average primary particle size of 169 nm.

[0565] Experimental Example 4: 120 g of PTFE aqueous dispersion 3 obtained in polymerization example 2 was mixed with aqueous ammonia to adjust the pH to 7.0. Then, 1.2 g of acid-degradable nonionic surfactant KP-110 was added. Next, 28.8 g of anion exchange resin (A400OH, manufactured by Purolite) was added and the mixture was stirred for 60 minutes at a strength that did not cause aggregation. After that, the anion exchange resin was removed using a mesh to obtain PTFE aqueous dispersion 4. The solid content concentration of PTFE aqueous dispersion 4 was 20.0%, and the pH was 10.3.

[0566] PTFE powder was obtained in the same manner as in Experimental Example 1, except that PTFE aqueous dispersion 4 was used.

[0567] The peak temperature of the obtained PTFE powder measured by DSC was 335°C. Furthermore, the obtained PTFE powder contained the general formula (12): [H-(CF ２ ) ｍ－１ CO ２ － ] M ＋ (In the formula, m is 12, M ＋ ) represents a cation. ) was below the limit of quantification. In accordance with ASTM D4895-89, the color L* value of the test specimen prepared from PTFE powder was 89.6.

[0568] Polymerization Example 3: An aqueous dispersion 5 was obtained by the method described in Production Example 2 of International Publication No. 2022 / 050430. The solid content concentration of the obtained PTFE aqueous dispersion 5 was 30.0% by mass, and the average primary particle size was 270 nm.

[0569] Experimental Example 5: PTFE powder was obtained in the same manner as in Experimental Example 4, except that PTFE aqueous dispersion 5 was used.

[0570] In accordance with ASTM D4895-89, the color L* value of the test specimen prepared from PTFE powder was 90.2.

[0571] Experimental Example 6 (Comparison): Ion exchange was performed in the same manner as in Experimental Example 5, except that KP-110 was replaced with TDS-80, to obtain PTFE aqueous dispersion 6.

[0572] A wet polymer was obtained by coagulation in accordance with the method described in the examples of International Publication No. 2020 / 218622. The obtained wet polymer was dried at 160°C for 18 hours to obtain a PTFE solid.

[0573] In accordance with ASTM D4895-89, the color L* value of the test specimen prepared from PTFE solids was 44.0.

[0574] Experimental Example 7: 120 g of PTFE aqueous dispersion 3 obtained in polymerization example 2 was mixed with 1.8 g of a 40% aqueous solution of the thermally decomposable amphoteric surfactant decyldimethylamine N-oxide. Then, 28.8 g of anion exchange resin (A400OH, manufactured by Purolite) was added, and the mixture was stirred for 60 minutes at a strength that did not cause aggregation. After that, the anion exchange resin was removed using a mesh to obtain PTFE aqueous dispersion 7. The solid content concentration of PTFE aqueous dispersion 7 was 19.7%, and the pH was 10.4.

[0575] To 100 g of the obtained PTFE aqueous dispersion, 347.7 g of water was added, and the mixture was coagulated by high-speed stirring to obtain a wet polymer. The obtained wet polymer was dried at 160°C for 18 hours to obtain PTFE powder.

[0576] The peak temperature of the obtained PTFE powder by DSC was 335°C, and the electrostatic evaluation was ◎ (very good). The charge was -0.6 nC / g. In addition, the obtained PTFE powder contained the general formula (12): [H-(CF ２ ) ｍ－１ CO ２ － ] M ＋ (In the formula, m is 12, M ＋ ∫ represents a cation. ∫ was below the limit of quantification, and the EOF was 3.6 ppm by mass. According to ASTM D4895-89, the color L* value of the test specimen prepared from PTFE powder was 89.9.

[0577] Polymerization Example 4 <Preparation of Raw Material Solution A> 3309 g of deionized water was placed in a 6.0 L stainless steel pressure-resistant reaction vessel, the reactor was sealed, and while heating to 70°C, suction was applied and the reactor was purged with TFE to remove oxygen from the reactor, and the contents were stirred. Then, 233.2 g of perfluoro(methyl vinyl ether) and 41.0 g of TFE were placed in the reactor, and the temperature was raised to 90°C while stirring at 120 rpm. Next, 0.83 g of ammonium persulfate (APS) dissolved in 10 g of deionized water was added as an initiator to start polymerization. As polymerization began, the pressure in the reactor decreased, so TFE was added to maintain a constant pressure. After 8 g of TFE was injected under pressure, the supply of TFE was stopped, stirring was stopped, and the reaction was terminated. Then, the reactor was evacuated until the pressure in the reactor reached atmospheric pressure, the contents were removed from the reactor and cooled to obtain Raw Material Solution A. The solid content concentration of Raw Material Solution A was 0.61 mass%.

[0578] <Preparation of Raw Material Solution B> 127 g of AmberLite HPR650H (DuPont, cation exchange resin) was added to 3100 g of Raw Material Solution A. 60 minutes after starting stirring, the raw material solution and ion exchange resin were filtered off. 127 g of Purolite A300 (Purolite, anion exchange resin) was added to the filtered raw material solution. 60 minutes after starting stirring, the raw material solution and ion exchange resin were filtered off to obtain Raw Material Solution B. The solid content concentration of Raw Material Solution B was 0.56% by mass.

[0579] <Preparation of Aqueous Dispersion 8> 1158 g of deionized water, 2442 g of raw material solution B, and 180 g of paraffin wax were charged into a 6.0 L stainless steel pressure reactor. The reactor was sealed and heated to 70°C while suction was applied, and the reactor was purged with TFE to remove oxygen. The contents were stirred at 160 rpm. 0.06 g of ammonium persulfate dissolved in 10 g of deionized water was added, and the reactor pressure was increased to 1.4 MPaG using TFE. A decrease in pressure was observed, and thereafter TFE was added to the reactor to maintain the pressure at 1.4 MPaG. When the amount of TFE consumed in the reaction reached 685 g, the supply of TFE was stopped, stirring was stopped, and the reaction was terminated. After that, the reactor was evacuated until the pressure returned to atmospheric pressure, the contents were removed from the reactor and cooled, and the separated paraffin was removed to obtain PTFE aqueous dispersion 8.

[0580] The obtained PTFE aqueous dispersion 8 had a solid content concentration of 16.9% by mass and an average primary particle size of 198 nm.

[0581] The total content of the compounds represented by the following two general formulas in the PTFE aqueous dispersion 8 was 28,783 ppb by mass relative to the PTFE. General formula (6-18-1): M ＋ [ － OOC-(CF ２ ) １６ - COO － ] M ＋ (In the formula, M ＋ (where represents a cation) General formula (6-18-2): M ＋ [ － OOC-(CF ２ ) １５ - (CF (OCF ３ )) １ - COO － ] M ＋ (In the formula, M ＋ represents a cation. -CF ２ - and -CF (OCF ３ The order of existence of the elements in the formula is arbitrary.

[0582] PTFE aqueous dispersion 8 contains general formula (12): [H-(CF ２ ) ｍ－１ CO ２ － ] M＋ (In the formula, m is 12, M ＋ The compound represented by (where represents a cation) was 344 mass ppb relative to PTFE.

[0583] Experimental Example 8: PTFE powder was obtained in the same manner as in Experimental Example 1, except that PTFE aqueous dispersion 8 was used.

[0584] The obtained PTFE powder contains the general formula (12): [H-(CF ２ ) ｍ－１ CO ２ － ] M ＋ (In the formula, m is 12, M ＋ The compound represented by ( ) represents a cation. The concentration of the compound was below the limit of quantification. In accordance with ASTM D4895-89, the color L* value of the test specimen prepared from the PTFE powder was 80.2. Furthermore, the total content of the compound represented by general formula (6-18-1) and the compound represented by general formula (6-18-2) in the obtained PTFE powder was both below the limit of quantification.

[0585] Experimental Example 9: PTFE powder was obtained in the same manner as in Experimental Example 7, except that PTFE aqueous dispersion 8 was used.

[0586] The electrostatic properties of the obtained PTFE powder were evaluated as excellent (◎). The charge was -1.8 nC / g.

[0587] The obtained PTFE powder contains the general formula (12): [H-(CF ２ ) ｍ－１ CO ２ － ] M ＋ (In the formula, m is 12, M ＋ The compound represented by ( ) represents a cation. The concentration of the compound was below the limit of quantification. In accordance with ASTM D4895-89, the color L* value of the test specimen prepared from the PTFE powder was 80.2. Furthermore, the total content of the compound represented by general formula (6-18-1) and the compound represented by general formula (6-18-2) in the obtained PTFE powder was both below the limit of quantification.

[0588] <Polymerization Example 5> In a 6.0 L stainless steel pressure-resistant reaction vessel, 3300 g of deionized water and 180 g of paraffin wax were charged. The reactor was sealed, and while heating to 70°C, suction was applied and the reactor was purged with TFE to remove oxygen from the reactor, and the contents were stirred. Then, 244 g of PMVE and 21 g of TFE were charged, and the temperature was raised to 90°C while stirring, and the pressure was set to 1.3 MPaG. Next, 0.84 g of ammonium persulfate (APS) dissolved in 10 g of deionized water was added as an initiator to start polymerization. As polymerization began, the pressure in the reactor decreased, so TFE was added to maintain a constant pressure. When 14 g of TFE was injected under pressure, the supply of TFE was stopped, stirring was stopped, and the reaction was terminated. The reactor was evacuated until the pressure in the reactor reached atmospheric pressure, and the monomers were removed. Then, nitrogen was injected under pressure to 0.2 MPaG, and the reaction vessel was set to 90°C. After heating for 3 hours, the mixture was cooled to 70°C and 280 g of deionized water was added. While maintaining the temperature at 70°C, the contents were stirred by simultaneously purging the reactor with TFE while suctioning the inside of the reactor. 0.06 g of ammonium persulfate dissolved in 10 g of deionized water was added, and the reactor pressure was increased to 1.4 MPaG using TFE. A decrease in pressure was observed, and thereafter, TFE was added to the reactor to maintain the pressure at 1.4 MPaG. When the amount of TFE consumed in the reaction reached 685 g, the supply of TFE was stopped, stirring was stopped, and the reaction was terminated. After that, the reactor was evacuated until the pressure returned to atmospheric pressure, the contents were removed from the reactor and cooled, and the separated paraffin was removed to obtain PTFE aqueous dispersion 9. The solid content concentration of the obtained PTFE aqueous dispersion 9 was 19.2% by mass, and the average primary particle size was 199 nm.

[0589] The total content of the compounds represented by the following two general formulas in the PTFE aqueous dispersion 9 was 32,132 ppb by mass relative to the PTFE. General formula (6-18-1): M ＋ [ － OOC-(CF ２ ) １６ - COO － ] M ＋ (In the formula, M+ represents a cation) General formula (6-18-2): M ＋ [ － OOC-(CF ２ ) １５- (CF (OCF ３ )) １ - COO － ] M ＋ (In the formula, M ＋ represents a cation. -CF ２ - and -CF (OCF ３ The order of existence of the elements in the formula is arbitrary.

[0590] PTFE aqueous dispersion 9 contains general formula (12): [H-(CF ２ ) ｍ－１ CO ２ － ] M ＋ (In the formula, m is 12, M ＋ The compound represented by (where represents a cation) was 403 ppb by mass relative to PTFE.

[0591] <Experimental Example 10> PTFE powder was obtained in the same manner as in Experimental Example 1, except that PTFE aqueous dispersion 9 was used.

[0592] The obtained PTFE powder contains the general formula (12): [H-(CF ２ ) ｍ－１ CO ２ － ] M ＋ (In the formula, m is 12, M ＋ The compound represented by ( ) represents a cation. The concentration of the compound was below the limit of quantification. In accordance with ASTM D4895-89, the color L* value of the test specimen prepared from the PTFE powder was 80.2. Furthermore, the content of the compound represented by general formula (6-18-1) and the compound represented by general formula (6-18-2) in the obtained PTFE powder was both below the limit of quantification.

Claims

1. A method for producing a fluoropolymer, comprising: preparing an aqueous dispersion containing a fluoropolymer by emulsion polymerization of a fluoromonomer; adding a biodegradable surfactant to the aqueous dispersion; contacting the aqueous dispersion containing the biodegradable surfactant with an adsorbent; then removing the adsorbent to recover the aqueous dispersion that has been in contact with the adsorbent; coagulating the fluoropolymer in the recovered aqueous dispersion; and drying the resulting coagulation to obtain the fluoropolymer.

2. The manufacturing method according to claim 1, wherein the degradable surfactant is at least one selected from the group consisting of acid hydrolyzable surfactants, base hydrolyzable surfactants, enzymatically degradable surfactants, and thermally degradable surfactants.

3. The manufacturing method according to claim 1 or 2, wherein the decomposable surfactant is at least one selected from the group consisting of acid hydrolyzable surfactants and thermally decomposable surfactants.

4. The manufacturing method according to any one of claims 1 to 3, wherein the degradable surfactant is at least one selected from the group consisting of degradable nonionic surfactants and degradable amphoteric surfactants.

5. The manufacturing method according to any one of claims 1 to 4, wherein the degradable surfactant is a degradable nonionic surfactant containing at least one Si.

6. The manufacturing method according to any one of claims 1 to 5, wherein the degradable surfactant is a degradable nonionic surfactant having a siloxane bond.

7. The manufacturing method according to claim 1 or 2, wherein the degradable surfactant is alkyldimethylamine oxide.

8. The manufacturing method according to claim 1 or 2, wherein the biodegradable surfactant is cellulose.

9. The manufacturing method according to any one of claims 1 to 8, wherein the amount of the biodegradable surfactant used is 0.1% by mass or more relative to the mass of the fluoropolymer in the aqueous dispersion.

10. The manufacturing method according to any one of claims 1 to 9, wherein the adsorbent is at least one selected from the group consisting of ion exchange resin, synthetic adsorbent, silica gel, polymer adsorbent, activated carbon, diatomaceous earth, and zeolite.

11. The manufacturing method according to any one of claims 1 to 10, wherein the adsorbent is an anion exchange resin.

12. The manufacturing method according to claim 1 or 2, comprising: (1) preparing an aqueous dispersion (1) containing a fluoropolymer by emulsion polymerization of a fluoromonomer; (2) preparing an aqueous dispersion (2) containing the acid hydrolyzable surfactant and having a pH greater than 4.5 by adding an acid hydrolyzable surfactant to the aqueous dispersion (1); (3) recovering the aqueous dispersion (3) by contacting the aqueous dispersion (2) with an adsorbent and then removing the adsorbent; (4) adding an acid to the aqueous dispersion (3) to adjust the pH to 4.5 or less, and stirring the aqueous dispersion (3) to coagulate the fluoropolymer in the aqueous dispersion (3) and recovering the coagulated product; and (5) drying the coagulated product to produce the fluoropolymer.

13. Aqueous dispersion (1) contains general formula (12): [H-(CF ２ ) ｍ－１ CO ２ － ] M ＋ (In the formula, m is 12, M ＋ The method for producing a product according to claim 12, further comprising at least one selected from the group consisting of a compound represented by ( and extractable organofluorine compounds (EOFs), where represents a cation.

14. The manufacturing method according to any one of claims 1 to 13, wherein the fluoropolymer is polytetrafluoroethylene.

15. General formula (12): [H-(CF ２ ) ｍ－１ CO ２ － M ＋ (where m is 12, and M ＋ represents a cation.), a compound represented thereby, and an extractable organic fluorine compound (EOF) is not substantially contained, and the color tone L* value of a test piece prepared in accordance with ASTM D4895-89 is 50 or more, contains a functional group, and a fluoropolymer having an average primary particle diameter of 500 nm or less.

16. The fluoropolymer according to claim 15, which is a powder of polytetrafluoroethylene.

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