Method for producing solid composition, and solid composition

Abstract

Provided is a method for producing a solid composition that contains a fluorine-containing elastomer which includes a structural unit based on at least one substance selected from the group consisting of tetrafluoroethylene and vinylidene fluoride, and which has a glass transition temperature of not higher than +10.0°C, said method comprising: an aqueous dispersion preparation step for preparing an aqueous dispersion which contains an aqueous medium and particles of the fluorine-containing elastomer dispersed in the aqueous medium; and an aggregation step for bringing the aqueous dispersion into contact with a liquid aqueous solution at a temperature not more than the glass transition temperature Tg of the fluorine-containing elastomer and aggregating the particles at an aggregation temperature of not higher than Tg + 5.0°C to obtain a solid composition containing an aggregate of the particles.

Description

Method for producing a solid composition and solid composition

[0001] This disclosure relates to a method for producing a solid composition and to a solid composition.

[0002] Crosslinked rubber articles obtained by crosslinking a composition containing a fluorine-containing elastomer are used in various industrial fields because they have excellent heat resistance, chemical resistance, flame retardancy, weather resistance, etc. The above-mentioned crosslinked rubber articles can be obtained, for example, by mixing additives such as crosslinking agents as needed with a solid composition containing a fluorine-containing elastomer and then crosslinking it.

[0003] As a method for obtaining the above-mentioned fluorine-containing elastomer, for example, Patent Document 1 discloses a production method in which a fluorine-containing monomer is emulsion-polymerized in the presence of an aqueous medium, an emulsifier having fluorine atoms, a chain transfer agent, and a radical polymerization initiator. By using the above production method, a crosslinkable fluorine-containing elastomer having iodine atoms, bromine atoms, or both iodine atoms and bromine atoms at the molecular ends can be obtained.

[0004] International Publication No. 2010 / 082633

[0005] When obtaining crosslinked rubber articles using a solid composition containing a fluorine-containing elastomer, a fast crosslinking rate of the solid composition is required from the viewpoint of productivity. However, as described in Patent Document 1, solid compositions containing a fluorine-containing elastomer obtained by polymerization in the presence of an emulsifier containing fluorine atoms may have a slow crosslinking rate.

[0006] This disclosure has been made in view of these circumstances, and one embodiment of this disclosure aims to solve the problem of providing a method for producing a solid composition containing a fluorine-containing elastomer and having a fast crosslinking rate. Another embodiment of this disclosure aims to solve the problem of providing a solid composition containing a fluorine-containing elastomer and having a fast crosslinking rate.

[0007] This disclosure includes the following embodiments: <1> A method for producing a solid composition containing a fluorine-containing elastomer comprising a constituent unit based on at least one selected from the group consisting of tetrafluoroethylene and vinylidene fluoride, wherein the elastomer has a glass transition temperature of +10.0°C or less, comprising: an aqueous dispersion preparation step of preparing an aqueous dispersion containing an aqueous medium and particles of the fluorine-containing elastomer dispersed in the aqueous medium; and an aggregation step of bringing the aqueous dispersion into contact with a liquid aqueous solution containing water and having a temperature of Tg or less, when the glass transition temperature of the fluorine-containing elastomer is Tg, and agglomerating the particles at an aggregation temperature of Tg + 5.0°C or less to obtain a solid composition containing aggregates of the particles. <2> The method for producing a solid composition according to <1>, wherein the volume average particle size D50A of the aggregates contained in the solid composition separated from the liquid aqueous solution at an aggregation temperature of ±5.0°C is 500 μm or less. <3> The method for producing a solid composition according to <1> or <2>, wherein the volume median particle size D50B of the aggregates in the liquid aqueous solution is 500 μm or less. <4> The method for producing a solid composition according to any one of <1> to <3>, wherein the liquid aqueous solution contains an alcohol having 1 to 4 carbon atoms and a boiling point of less than 100°C. <5> The method for producing a solid composition according to any one of <1> to <4>, wherein the liquid aqueous solution contains an inorganic salt. <6> The method for producing a solid composition according to any one of <1> to <5>, wherein the fluorine-containing elastomer comprises a structural unit based on tetrafluoroethylene and a structural unit based on perfluoro(alkyl vinyl ether). <7> The method for producing a solid composition according to any one of <1> to <6>, wherein the fluorine-containing elastomer has at least one selected from the group consisting of a chlorine atom, a bromine atom, an iodine atom, and a cyano group. <8> A method for producing a solid composition according to any one of <1> to <7>, wherein the aqueous dispersion preparation step includes a polymerization step of polymerizing a monomer containing at least one selected from the group consisting of tetrafluoroethylene and vinylidene fluoride in the aqueous medium.

[0008] <9> A fluorine-containing elastomer containing a structural unit based on at least one selected from the group consisting of tetrafluoroethylene and vinylidene fluoride and having a glass transition temperature of +10.0 °C or lower, and at least one selected from the group consisting of the compound (S1) represented by the formula (S1) and the compound (S2) represented by the formula (S2). A solid composition, wherein the total content of the compound (S1) and the compound (S2) with respect to the whole solid composition is less than 250 mass ppb. H(CF ２ ) ｐ１ COOM １ (S1) H(CF ２ ) ｐ２ SO ３ M ２ (S2) In the formulas (S1) and (S2), M １ and M ２ are each independently a hydrogen atom, Na, K, or NH ４ , p1 is an integer of 3 to 13, and p2 is an integer of 4 to 10.

[0009] <10> A solid composition containing a fluorine-containing elastomer containing a structural unit based on at least one selected from the group consisting of tetrafluoroethylene and vinylidene fluoride and having a glass transition temperature of +10.0 °C or lower, wherein the solid composition does not contain the compound (S1) represented by the formula (S1), the compound (S2) represented by the formula (S2), the compound (S3) represented by the formula (S3), the compound (S4) represented by the formula (S4), the compound (S5) represented by the formula (S5), the compound (S6) represented by the formula (S6), the compound (S7) represented by the formula (S7), the compound (S8) represented by the formula (S8), the compound (S9) represented by the formula (S9), and the compound (S10) represented by the formula (S10), or contains at least one selected from the group consisting of the compounds (S1) to (S10) and the total content of the compounds (S1) to (S10) is less than 250 mass ppb with respect to the solid composition. H(CF ２ ) ｐ１ COOM １ (S1) H(CF ２ ) ｐ２ SO ３ M ２(S2) F(CF) ２ ) ｐ３ COOM ３ (S3) F(CF) ２ ) ｐ４ SO ３ M ４ (S4) X ５１ (CF ２ ) ｐ５ (OCF ２ CF ２ CF ２ ) ｑ５ OCF(X ５２ ) CF ２ COOM ５ (S5) X ６１ (CF ２ ) ｐ６ (OCF(X ６２ ) CF(X ６３ )) ｑ６ OCF(X ６４ ) COOM ６ (S6) X ７１ (CF ２ ) ｐ７ CF(X ７２ ) (OCF(X ７３ ) CF(X ７４ )) ｑ７ OCF(X ７５ ) COOM ７ (S7)

[0010]

[0011] X １０１ CF ２ (OCF ２ CF ２ ) ｑ１０ (OCF ２ ) ｒ１０ X １０２ (S10) In formulas (S1) to (S10), M １ ~M ９ Each is independently a hydrogen atom, Na, K, or NH ４ X ５１ , X ６１ , X ７１ , X ８１ , X ８２ , X ９１ , and X ９２ Each of these is independently a hydrogen atom, a fluorine atom, or a chlorine atom, and X１０１ and X １０２ Each of these is independently a hydrogen atom, a fluorine atom, a COOH group, or a chlorine atom, and X １０１ and X １０２ At least one of them is COOH, X ５２ , X ６２ ~X ６４ , and X ７２ ~X ７５ Each of these is independently a hydrogen atom, a fluorine atom, or a perfluoroalkyl group having 1 to 3 carbon atoms, and Rf ８ ~Rf ９ Each is independently a fluorine-containing alkylene group having 1 to 20 carbon atoms, p1 and p3 are independently integers from 3 to 13, p2 and p4 are independently integers from 4 to 10, p5 to p7 are independently integers from 1 to 10, q5 to q7 are independently integers from 0 to 3, q8 to q9 are independently integers from 1 to 20, n8 to n9 are independently integers from 1 to 30, and q8 and n8 are the CF of compound (S8). ２ A combination of integers such that the number of elements is 30 or less, where q9 and n9 are the CFs of the compound (S9). ２ The integer combination is such that the number of groups is 30 or less, q10 and r10 are each independent integers of 0 or greater, and q10 and r10 are integer combinations such that the number-average molecular weight of the compound (S10) is between 300 and 1000.

[0012] <11> A solid composition containing a fluorine-containing elastomer comprising a structural unit based on at least one selected from the group consisting of tetrafluoroethylene and vinylidene fluoride, wherein the glass transition temperature is +10.0°C or lower, and comprising 1 or more CF ２ It has a group and one or more ionic functional groups, wherein the ionic functional groups are COOM, SO ３ M, PO ４ M, or SO ４ M is a hydrogen atom, Na, K, or NH ４ The CF per ionic functional group ２When compound (B) is defined as a compound having 30 or fewer groups, lacking carbon-carbon double bonds and carbon-carbon triple bonds, and having a number-average molecular weight of 3000 or less, the solid composition either does not contain compound (B) or contains compound (B) such that the total content of compound (B) is less than 250 ppb by mass relative to the solid composition.

[0013] <12> The solid composition according to any one of <9> to <11>, wherein the solid composition contains aggregates of particles containing the fluorine-containing elastomer, and the volume average particle size D50A of the aggregates is 500 μm or less. <13> The solid composition according to any one of <9> to <12>, wherein the fluorine-containing elastomer comprises a structural unit based on tetrafluoroethylene and a structural unit based on perfluoro(alkyl vinyl ether). <14> The solid composition according to any one of <9> to <13>, wherein the fluorine-containing elastomer has at least one selected from the group consisting of chlorine atoms, bromine atoms, iodine atoms, and cyano groups. <15> The solid composition according to any one of <9> to <14>, wherein the storage modulus G' of the solid composition is 10 to 1000 kPa. <16> The solid composition according to any one of <9> to <15>, wherein the 5% mass thermal weight loss temperature of the solid composition is 350°C or higher.

[0014] <17> A solid composition containing a fluorine-containing elastomer having a glass transition temperature of +10.0°C or lower, comprising a structural unit based on at least one selected from the group consisting of tetrafluoroethylene and vinylidene fluoride, wherein the solid composition contains aggregates of particles containing the fluorine-containing elastomer, and the volume average particle size D50A of the aggregates is 500 μm or less. <18> The solid composition according to <17>, wherein the fluorine-containing elastomer comprises a structural unit based on tetrafluoroethylene and a structural unit based on perfluoro(alkyl vinyl ether). <19> The solid composition according to <17 or 18>, wherein the fluorine-containing elastomer has at least one selected from the group consisting of chlorine atoms, bromine atoms, iodine atoms, and cyano groups. <20> The solid composition according to any one of <17> to <19>, wherein the storage modulus G' of the solid composition is 10 to 1000 kPa. <21> The solid composition according to any one of <17> to <20>, wherein the 5% mass thermal weight loss temperature of the solid composition is 350°C or higher. <22> The solid composition according to any one of <9> to <21>, wherein the content of the metal element in the solid composition is 50 ppm or less relative to the solid composition.

[0015] According to one embodiment of the present disclosure, a method for producing a solid composition containing a fluorine-containing elastomer and having a fast crosslinking rate is provided. Furthermore, according to another embodiment of the present disclosure, a solid composition containing a fluorine-containing elastomer and having a fast crosslinking rate is provided.

[0016] In this disclosure, numerical ranges indicated using "~" include the numbers before and after "~" as the minimum and maximum values, respectively. In numerical ranges described in stages in this disclosure, the upper or lower limit of one numerical range may be replaced by the upper or lower limit of another numerical range described in stages. Also, in numerical ranges described in this disclosure, the upper or lower limit of that range may be replaced by the values ​​shown in the examples. In this disclosure, each component may contain multiple types of the corresponding substance. If multiple types of the substance corresponding to each component are present in the composition, the content of each component means the total content of the multiple types of substances present in the composition unless otherwise specified. In this disclosure, each component may contain multiple types of particles. If multiple types of particles corresponding to each component are present in the composition, the particle size of each component means the value for a mixture of the multiple types of particles present in the composition unless otherwise specified. In this disclosure, "elastomer" refers to a non-melting, elastic, fluorine-containing polymer exhibiting a storage modulus G' of 80 kPa or higher at 100°C and a frequency of 50 cpm, as measured in accordance with ASTM D6204, and is distinct from fluororesins. In this disclosure, the number-average molecular weight (Mn) is a value measured by gel permeation chromatography (GPC) using polystyrene as a standard substance.

[0017] [Method for Producing a Solid Composition] The method for producing a solid composition according to the present disclosure (hereinafter also referred to as "the present production method") is a method for producing a solid composition containing a fluorine-containing elastomer which includes a constituent unit based on at least one selected from the group consisting of tetrafluoroethylene and vinylidene fluoride and has a glass transition temperature of +10.0°C or lower. Here, the solid composition is solid at 25°C. The present production method comprises an aqueous dispersion preparation step of preparing an aqueous dispersion containing an aqueous medium and particles of the fluorine-containing elastomer dispersed in the aqueous medium, and an aggregation step of bringing the aqueous dispersion into contact with a liquid aqueous solution containing water and having a temperature of Tg or lower, when the glass transition temperature of the fluorine-containing elastomer is Tg, and agglomerating the particles at an aggregation temperature of Tg + 5.0°C or lower to obtain a solid composition containing aggregates of the particles.

[0018] Hereinafter, tetrafluoroethylene will also be referred to as "TFE," a constituent unit based on TFE will be referred to as a "TFE unit," vinylidene fluoride will also be referred to as "VdF," a constituent unit based on VdF will be referred to as a "VdF unit," at least one selected from the group consisting of TFE and VdF will be referred to as "TFE and / or VdF," a constituent unit based on at least one selected from the group consisting of TFE and VdF will be referred to as a "TFE unit and / or VdF unit," the glass transition temperature of a fluorine-containing elastomer will also be referred to as "Tg," and a fluorine-containing elastomer containing TFE units and / or VdF units with a Tg of +10.0°C or less will also be referred to as a "specific elastomer."

[0019] The solid composition obtained by this manufacturing method was found to have a fast crosslinking rate when manufacturing crosslinked rubber articles. The reason for this is not clear, but it is speculated to be as follows: For example, when a fluorine-containing monomer is polymerized in the presence of an emulsifier containing fluorine atoms, the emulsifier used remains in the aqueous dispersion in which the fluorine-containing elastomer polymer particles are dispersed. Then, when the particles in the aqueous dispersion are aggregated to obtain a solid composition, the emulsifier is incorporated into the solid composition, and a solid composition containing a large amount of emulsifier containing fluorine atoms may be obtained. Furthermore, even when a fluorine-containing monomer is polymerized without using an emulsifier containing fluorine atoms, a compound equivalent to an emulsifier containing fluorine atoms may be produced as a by-product, and a solid composition containing a large amount of emulsifier containing fluorine atoms may be obtained. In this way, when a solid composition contains a large amount of emulsifier containing fluorine atoms, the crosslinking reaction of the fluorine-containing elastomer may be inhibited by the emulsifier during the crosslinking process, and the crosslinking rate may be slowed down.

[0020] In contrast, in this manufacturing method, the particles of the fluorine-containing elastomer are aggregated at Tg + 5.0°C or lower during the aggregation process. It has been found that by setting the aggregation temperature to Tg + 5.0°C or lower in this manufacturing method, the particle size of the aggregates becomes smaller. When the particle size of the aggregates is small, it is thought that components other than the fluorine-containing elastomer particles are less likely to be incorporated into the aggregates. Therefore, even if an emulsifier containing fluorine atoms is contained in the aqueous dispersion, it is less likely to be incorporated into the aggregates, and it is thought that a solid composition with a low content of emulsifier containing fluorine atoms can be obtained. Furthermore, it is presumed that the low content of emulsifier containing fluorine atoms in the solid composition will lessen the inhibition of the crosslinking reaction of the fluorine-containing elastomer during the crosslinking process, resulting in a faster crosslinking rate. For these reasons, it is presumed that a solid composition with a fast crosslinking rate can be obtained with this manufacturing method.

[0021] This manufacturing method comprises at least the aqueous dispersion preparation step and the coagulation step, and may include other steps as described below if necessary. The steps of this manufacturing method will be described below.

[0022] <Aqueous Dispersion Preparation Step> In the aqueous dispersion preparation step, an aqueous dispersion is prepared in which particles of a specific elastomer are dispersed in an aqueous medium. The aqueous dispersion may be prepared by adding the particles of the specific elastomer to the aqueous medium, or by polymerizing a monomer containing TFE and / or VdF in the aqueous medium. It is desirable that the aqueous dispersion preparation step include a polymerization step in which a monomer containing TFE and / or VdF is polymerized in the aqueous medium. Examples of methods for obtaining an aqueous dispersion in which particles of a specific elastomer are dispersed in an aqueous medium by polymerizing a monomer containing TFE and / or VdF in the aqueous medium include the following manufacturing methods A and B. When the aqueous dispersion preparation step includes the following manufacturing method A as a polymerization step, aqueous dispersion A described later is prepared. When the aqueous dispersion preparation step includes the following manufacturing method B as a polymerization step, a second aqueous dispersion described later is prepared.

[0023] (Production Method A) Production Method A includes a step of polymerizing monomer A containing TFE and / or VdF in the presence of a compound (X) represented by the following formula (X) and an aqueous medium. CX １ X ２ =CX ３ -L-Z...(X) In formula (X), X １ and X ２ are each independently a hydrogen atom, a chlorine atom, or an alkyl group, X ３ is a hydrogen atom or an alkyl group, L is a single bond or a divalent linking group, and Z is an anionic group or a salt of an anionic group.

[0024] -Emulsifier, etc.- Production Method A may be carried out in the presence of an emulsifier having a fluorine atom, or may be carried out under conditions where an emulsifier having a fluorine atom is substantially absent. In this production method, as will be described later, since the agglomeration temperature in the agglomeration step is Tg + 5.0°C or lower, even if monomer A is polymerized in the presence of an emulsifier having a fluorine atom, the emulsifier having a fluorine atom is hardly incorporated into the solid composition. However, from the viewpoint of obtaining a solid composition with a faster crosslinking rate, it is preferably carried out under conditions where an emulsifier having a fluorine atom is substantially absent. Substantially absent of an emulsifier having a fluorine atom means that in the production of a fluorine-containing elastomer, the content of the emulsifier having a fluorine atom is 10 mass ppm or less with respect to the total amount of the aqueous medium, preferably 150 mass ppb or less, and more preferably 50 mass ppb or less. The lower limit of the content of the emulsifier having a fluorine atom is 0 mass ppb.

[0025] Manufacturing method A is preferable to be carried out under conditions where emulsifiers containing fluorine atoms and emulsifiers without fluorine atoms are substantially absent, in order to obtain a solid composition with a faster crosslinking rate. The statement that emulsifiers containing fluorine atoms and emulsifiers without fluorine atoms (hereinafter collectively referred to as "emulsifiers") are substantially absent means that, in the production of fluorine-containing elastomers, the emulsifier content is 10 ppm by mass or less, preferably 150 ppb by mass or less, and more preferably 50 ppb by mass or less, relative to the total amount of the aqueous medium. The lower limit of the emulsifier content is 0 ppb by mass. The content of various emulsifiers can be measured using a liquid chromatograph-mass spectrometer.

[0026] Examples of emulsifiers include water-soluble emulsifiers. A water-soluble emulsifier means an emulsifier whose solubility in 1000 g of water at 25°C is 100 mg or more, while a non-water-soluble emulsifier means an emulsifier other than the water-soluble emulsifiers mentioned above. Water-soluble emulsifiers may be either ionic or nonionic. Examples of emulsifiers include those that do not have a carbon-carbon double bond. Note that compound (X) mentioned above does not qualify as an emulsifier. Furthermore, in manufacturing method A and manufacturing method B described later, the monomers used in polymerization and the fluorine-containing elastomers obtained by polymerization do not qualify as emulsifiers.

[0027] A fluorine-free emulsifier is an emulsifier that does not contain fluorine atoms and has hydrocarbon groups such as alkyl groups as its hydrophobic portion. It is also possible to substitute the hydrogen atoms of the hydrocarbon groups of a fluorine-free emulsifier with halogen atoms other than fluorine atoms. Examples of fluorine-free emulsifiers include ionic hydrocarbon emulsifiers and nonionic hydrocarbon emulsifiers.

[0028] Examples of ionic hydrocarbon emulsifiers include anionic hydrocarbon emulsifiers. Anionic hydrocarbon emulsifiers refer to emulsifiers having a negatively charged hydrophilic portion such as a carboxylic acid group, sulfonic acid group, sulfate group, phosphonic acid group, and phosphate group, and a hydrocarbon group such as an alkyl group as a hydrophobic portion. Specific examples of anionic hydrocarbon emulsifiers include sodium dodecyl sulfate, a highly branched C10 tertiary carboxylic acid supplied by Resolution Performance Products as Versatic® 10, sodium linear alkyl polyethersulfonate supplied by BASF as the Avanel® S series, and the sulfosuccinate emulsifier Lankropol® K8300 available from AkzoNobelSurfaceChemistryLLC.

[0029] Nonionic hydrocarbon emulsifiers are emulsifiers that exhibit surface activity without dissociating into ions in water and have hydrocarbon groups such as alkyl groups as hydrophobic portions. Examples of hydrophilic portions of nonionic hydrocarbon emulsifiers include water-soluble functional groups such as polyethylene oxide chains obtained from the polymerization of ethylene oxide. Examples of nonionic hydrocarbon emulsifiers include polyalkylene oxide block copolymers, such as block copolymers having polyethylene oxide and polypropylene oxide.

[0030] Another example of a nonionic hydrocarbon emulsifier is the emulsifier described in paragraphs

[0043] to

[0052] of Japanese Patent Publication No. 2016-537499.

[0031] Emulsifiers containing fluorine atoms and emulsifiers not containing fluorine atoms may also contain silicon atoms. Examples of emulsifiers containing silicon atoms include siloxane emulsifiers. Siloxane emulsifiers are hydrocarbon-containing emulsifiers having a siloxane skeleton. Examples of siloxane emulsifiers include those described in U.S. Patent No. 6,841,616 (Wille et al.) and U.S. Patent No. 7,977,438 (Brothers et al.).

[0032] The emulsifier having a fluorine atom and the emulsifier not having a fluorine atom may be a polymer emulsifier. Examples of the polymer emulsifier include polymers having a hydrophilic group in the side chain. Such polymer emulsifiers include, for example, polymers containing units based on compounds having a site capable of reacting by polymerization and a hydrophilic group. Further, even if it does not initially have a hydrophilic group, polymers containing units based on compounds having a group that can become a hydrophilic group and subjected to post-treatment such as hydrolysis are also included. Specific examples of the polymer emulsifier include methyl polymethacrylate, which is an emulsifier not having a fluorine atom.

[0033] When monomer A is polymerized under the condition that an emulsifier not having a fluorine atom is present, usually, 0.1 to 15 parts by mass of an emulsifier not having a fluorine atom is used with respect to 100 parts by mass of the aqueous medium.

[0034] - Aqueous medium - Production method A is carried out under the condition that an aqueous medium is present. Specific examples of the aqueous medium include water and a mixed solvent of water and a water-soluble organic solvent. Specific examples of the water-soluble organic solvent include tert-butanol, propylene glycol, dipropylene glycol, dipropylene glycol monomethyl ether, and tripropylene glycol.

[0035] - Compound (X) - Production method A is carried out under the condition that compound (X) is present. In formula (X), X １ and X ２ The alkyl groups represented by may be linear, branched, or cyclic. The number of carbon atoms of the above alkyl group is preferably 1 to 10, more preferably 1 to 3, and still more preferably 1. X １ and X ２ are both preferably hydrogen atoms from the viewpoint of increasing the number of particles of the obtained fluorine-containing elastomer. In formula (X), the specific examples and preferred embodiments of the alkyl group represented by X ３ are the same as the specific examples and preferred embodiments of the alkyl group in X １ and X ２ . X ３ is preferably a hydrogen atom from the viewpoint of increasing the number of particles of the obtained fluorine-containing elastomer.

[0036] In formula (X), the divalent linking group represented by L is an alkylene group, a carbonyl group, an ether bond, a thioether bond, a sulfonyl group, -NH-, or -SiH. ２ -, phenylene group, -CF ２ - and groups formed by combining two or more of these are examples. Examples of groups formed by combining two or more of these include ester bonds, thioester bonds, amide bonds, sulfonamide bonds, combinations of alkylene groups and ether bonds, combinations of alkylene groups and ester bonds, and combinations of alkylene groups and amide bonds. The alkylene group may be linear, branched, or cyclic, with linear or branched being preferred, and branched being more preferred. Examples of the number of carbon atoms in the alkylene group include 1 to 6, and 1 to 4 being preferred.

[0037] Specific examples of L include single bonds, alkylene groups, ether bonds, ester bonds, * Ｃ -CO-NH-R-* Ｚ Examples include single bonds, alkylene groups having 1 to 6 carbon atoms, and * Ｃ -CO-NH-R-* Ｚ Preferably, a single bond, an alkylene group having 1 to 2 carbon atoms, and * Ｃ -CO-NH-R-* Ｚ This is preferable. Here, * Ｃ * is the bonding site with the carbon atom in formula (X), Ｚ is the bonding site with Z in formula (X), and R is an alkylene group having 1 to 6 carbon atoms.

[0038] In formula (X), the anionic group represented by Z is, for example, -SO ３ H, -OSO ３ H, -P(=O)(OH) ２ , -OP(=O)(OH) ２Alternatively, -COOH can be used. Examples of salts of anionic groups include groups in which the hydrogen ion of the above anionic group is replaced with a cation other than a hydrogen ion. Examples of cations include metal ions, ammonium ions, imidazolium cations, pyrrolidinium cations, pyridinium cations, piperidinium cations, and phosphonium cations. Examples of metal ions include alkali metal ions such as sodium ions, potassium ions, and lithium ions; and alkaline earth metal ions such as calcium ions and magnesium ions. Z is -SO ３ M, -OSO ３ M, -P (=O) (OM) ２ , -OP(=O)(OM) ２ Alternatively, -COOM is preferable. As for Z, from the viewpoint of productivity, -SO ３ M and -COOM are preferred, and -SO ３ Na and -COONa are more preferred, and -SO ３ Na is even more preferable.

[0039] M is a hydrogen atom, a metal atom, N (R Ｍ１ ) ４ or P(R) Ｍ２ ) ４ And R Ｍ１ and R Ｍ２ Each of these is independently a hydrogen atom or a substituent. The metal atom represented by M is preferably a metal atom of Group 1, and more preferably Li, Na, or K. Ｍ１ and R Ｍ２ The substituent represented by is preferably a monovalent organic group, more preferably a monovalent hydrocarbon group, and even more preferably an alkyl group or an aromatic hydrocarbon group. The substituent has 1 to 10 carbon atoms. The alkyl group may be linear, branched, or cyclic. The aromatic hydrocarbon group may be monocyclic or polycyclic. A phenyl group is preferred as the aromatic hydrocarbon group.

[0040] Examples of the molecular weight of compound (X) include 70 to 500, and from the viewpoint of dispersion stability, 70 to 450 is preferred, and 100 to 300 is more preferred.

[0041] Specific examples of compound (X) include vinyl sulfonic acid, vinyl phosphonic acid, (meth)acrylic acid, allyl sulfonic acid, allyl phosphonic acid, butenic acid, crotonic acid, vinyl acetate, 2-sulfoethyl methacrylic acid, 4-vinylbenzenesulfonic acid, 2-acrylamido-2-methyl-1-propanesulfonic acid, N-tigroylglycine, 6-acrylamidohexanoic acid, 1,1-difluoro-2-methyl-2-[(1-oxo-2-propen-1-yl)amino]-1-propanesulfonic acid, 3-methyl-3-[(2-methyl-1-oxo-2-propen-1-yl)amino]-2-butanesulfonic acid, 2-methacrylamido-2-methylpropanesulfonic acid, 2,3-dimethyl-3-[(1-oxo-2-propen-1-yl)amino]-2-butanesulfonic acid, and their salts. Examples of the above-mentioned metal salts include salts of metal atoms represented by M.

[0042] The compound (X) is preferably a vinyl compound having a sulfonic acid group, a phosphonic acid group, or a carboxyl group, an allyl compound having a sulfonic acid group, a phosphonic acid group, or a carboxyl group, (meth)acrylic acid, (meth)acrylamide having a sulfonic acid group, a phosphonic acid group, or a carboxyl group, and metal salts thereof. Vinyl sulfonic acid, sodium vinyl sulfonate, allyl sulfonic acid, sodium allyl sulfonate, 2-acrylamide-2-methyl-1-propanesulfonic acid, sodium 2-acrylamide-2-methyl-1-propanesulfonate, 2-methacrylamide-2-methyl-1-propanesulfonic acid, or sodium 2-methacrylamide-2-methyl-1-propanesulfonate. Note that the above "(meth)acrylic acid" is a concept that includes both acrylic acid and methacrylic acid, and the above "(meth)acrylamide" is a concept that includes both acrylamide and methacrylamide.

[0043] The content of compound (X) is preferably 0.1 to 5000 ppm by mass, more preferably 0.2 to 1000 ppm by mass, even more preferably 0.3 to 500 ppm by mass, and particularly preferably 0.5 to 100 ppm by mass, relative to the total amount of the aqueous medium.

[0044] -Monomer A- In manufacturing method A, monomer A containing TFE and / or VdF is polymerized. Monomer A may contain other monomers in addition to TFE and / or VdF. Examples of other monomers include hexafluoropropylene (hereinafter also referred to as "HFP"), propylene, fluorine-containing vinyl ether, fluorine-containing allyl ether, etc.

[0045] Examples of fluorinated vinyl ethers include compounds represented by the following formula (1A): CF ２ =CF-O-R ｆ１ ...(1A) In formula (1A), R ｆ１ R represents a fluoroalkyl group having 1 to 10 carbon atoms. ｆ１ The number of carbon atoms is preferably 1 to 8, more preferably 1 to 6, even more preferably 1 to 5, and particularly preferably 1 to 3, from the viewpoint of superior polymerization reactivity. The fluoroalkyl group may be linear or branched. From the viewpoint of improving the heat resistance of the solid composition, the fluoroalkyl group is preferably a perfluoroalkyl group. From the viewpoint of improving the heat resistance of the solid composition, the fluorine-containing vinyl ether is preferably a perfluoro(alkyl vinyl ether) (hereinafter also referred to as "PAVE").

[0046] Specific examples of PAVE include perfluoro(methyl vinyl ether) (hereinafter also referred to as "PMVE"), perfluoro(ethyl vinyl ether) (hereinafter also referred to as "PEVE"), and perfluoro(propyl vinyl ether) (hereinafter also referred to as "PPVE"). Among these, PMVE or PPVE is preferred, with PMVE being more preferred, due to its superior polymerization reactivity.

[0047] Examples of fluorine-containing allyl ethers include compounds represented by the following formula (2A): CF ２ = CF - CF ２ O-R ｆ２ ...(2A) In formula (2A), R ｆ２ R represents a fluoroalkyl group having 1 to 10 carbon atoms. ｆ２The number of carbon atoms is preferably 1 to 8, more preferably 1 to 6, even more preferably 1 to 5, and particularly preferably 1 to 3, from the viewpoint of superior polymerization reactivity. The fluoroalkyl group may be linear or branched. From the viewpoint of improving the heat resistance of the solid composition, the fluoroalkyl group is preferably a perfluoroalkyl group. From the viewpoint of improving the heat resistance of the solid composition, the fluorine-containing allyl ether is preferably a perfluoro(alkylallyl ether) (hereinafter also referred to as "PAAE").

[0048] Specific examples of PAAEs include perfluoro(methyl allyl ether) (hereinafter also referred to as "PMAE"), perfluoro(ethyl allyl ether) (hereinafter also referred to as "PEAE"), and perfluoro(propyl allyl ether) (hereinafter also referred to as "PPAE"). Among these, PMAE or PPAE are preferred, with PMAE being more preferred, due to their superior polymerization reactivity.

[0049] Other monomers include, for example, ethylene, propylene, vinyl chloride, vinylidene chloride, chlorotrifluoroethylene, and fluoroalkylethylene.

[0050] It is preferable that monomer A further comprises at least one selected from the group consisting of PAVE, propylene, and HFP units, in addition to TFE and / or VdF. Monomer A may contain TFE and PAVE, TFE and propylene, TFE, VdF and HFP, or VdF and HFP. It is preferable that monomer A contains TFE and PAVE.

[0051] When monomer A contains TFE, the TFE content is preferably 10 to 90 mol%, more preferably 30 to 80 mol%, even more preferably 40 to 80 mol%, and particularly preferably 40 to 70 mol%, relative to the total amount of monomer A. When monomer A contains TFE and PAVE, the TFE content in monomer A is preferably 20 to 95 mol%, more preferably 25 to 85 mol%, and more preferably 35 to 75 mol%, relative to the total content of TFE and PAVE, from the viewpoint of superior polymerization reactivity. When monomer A contains TFE and PAVE, the total amount of TFE and PAVE used is preferably 80 to 99.9 mol%, more preferably 90 to 99.5 mol%, and even more preferably 95 to 99 mol%, relative to the amount of monomer A used. The preferred proportions are the same when PMVE is used as PAVE (i.e., when monomer A contains TFE and PMVE) and when PPVE is used as PAVE (i.e., when monomer A contains TFE and PPVE).

[0052] When monomer A contains TFE and propylene, the TFE content in monomer A is preferably 10 to 95 mol%, more preferably 20 to 85 mol%, and more preferably 25 to 75 mol%, relative to the total content of TFE and propylene, in order to obtain superior polymerization reactivity. When monomer A contains TFE and propylene, the total amount of TFE and propylene used is preferably 60 to 99.9 mol%, more preferably 70 to 99.5 mol%, and even more preferably 80 to 99 mol%, relative to the amount of monomer A used.

[0053] When monomer A contains TFE, VdF, and HFP, the TFE content in monomer A is preferably 3 to 60 mol%, more preferably 3 to 50 mol%, and more preferably 3 to 40 mol%, relative to the total content of TFE, VdF, and HFP, from the viewpoint of superior polymerization reactivity. When monomer A contains TFE, VdF, and HFP, the total amount of TFE, VdF, and HFP used is preferably 80 to 99.9 mol%, more preferably 90 to 99.5 mol%, and even more preferably 95 to 99 mol%, relative to the amount of monomer A used.

[0054] When monomer A contains VdF and HFP, the VdF content in monomer A is preferably 5 to 90 mol%, more preferably 8 to 80 mol%, and more preferably 10 to 70 mol%, relative to the total content of VdF and HFP, from the viewpoint of superior polymerization reactivity. When monomer A contains VdF and HFP, the total amount of VdF and HFP used is preferably 40 to 100 mol%, more preferably 50 to 100 mol%, and even more preferably 60 to 100 mol%, relative to the amount of monomer A used.

[0055] Furthermore, monomer A may further contain a crosslinking monomer for forming a crosslinked structure in the crosslinking process. Examples of crosslinking monomers include monomers having a cyano group, monomers having at least one selected from the group consisting of a chlorine atom, a bromine atom, and an iodine atom, and monomers having two or more polymerizable unsaturated bonds (hereinafter also referred to as "BO").

[0056] By polymerizing monomer A, which contains a monomer having a cyano group as a crosslinking monomer, a fluorine-containing elastomer having a cyano group can be obtained. Then, for example, by using a solid composition containing a fluorine-containing elastomer having a cyano group and a crosslinking agent, a crosslinked rubber having a crosslinked structure derived from a heterocycle, such as an oxazole ring structure formed by the reaction of the cyano group and the crosslinking agent, or a triazine ring structure formed by the reaction of cyano groups with each other, can be obtained. Hereinafter, the crosslinked structure derived from a heterocycle will also be called a "heterocyclic crosslinked structure," and the crosslinked body of a composition containing a fluorine-containing elastomer having one or more cyano groups will also be called a "CN-based crosslinked body."

[0057] Furthermore, by polymerizing monomer A, which contains a monomer having at least one selected from the group consisting of chlorine atoms, bromine atoms, and iodine atoms as a crosslinking monomer, a fluorine-containing elastomer having at least one selected from the group consisting of chlorine atoms, bromine atoms, and iodine atoms can be obtained. Then, for example, by using a solid composition containing a fluorine-containing elastomer having at least one selected from the group consisting of chlorine atoms, bromine atoms, and iodine atoms, and an organic peroxide as a crosslinking agent, a crosslinked rubber having a crosslinked structure via hydrocarbon groups such as alkyl groups can be obtained. Hereinafter, the crosslinked structure via hydrocarbon groups will also be called a "hydrocarbon crosslinked structure," and the crosslinked body of a composition containing a fluorine-containing elastomer having at least one selected from the group consisting of chlorine atoms, bromine atoms, and iodine atoms and an organic peroxide will also be called a "PO-based crosslinked body."

[0058] The monomer having a cyano group is not particularly limited as long as it is a compound having a cyano group and a polymerizable group, for example, a compound represented by the following formula (Y). CR １１ R １２ =CR １３ -R １４ -CN...(Y) In formula (Y), R １１ , R １２ , and R １３ Each of these independently represents a hydrogen atom, a fluorine atom, or a methyl group. １４ This refers to a divalent perfluorohydrocarbon group having 1 to 10 carbon atoms, or a group having an etheric oxygen atom at the terminal or between carbon-carbon bonds of a divalent perfluorohydrocarbon group having 1 to 10 carbon atoms.

[0059] Due to its excellent polymerization reactivity, R １１ , R １２ , and R １３ It is preferable that R is a fluorine atom or a hydrogen atom. １１ , R １２ , and R １３ It is more preferable that all of them are fluorine atoms or all of them are hydrogen atoms, as this provides superior release properties and heat resistance for the crosslinked rubber article. １１ , R １２ , and R １３It is particularly preferable that all of them are fluorine atoms. １４ The chain may be linear, branched, or cyclic, with linear or branched being preferred. １４ The number of carbon atoms is preferably 2 to 8, more preferably 3 to 7, even more preferably 3 to 6, and particularly preferably 3 to 5. １４ It may or may not have etheric oxygen atoms, but it is preferable to have etheric oxygen atoms because it provides superior rubber properties. １４ The number of etheric oxygen atoms in is preferably 1 to 3, and particularly preferably 1 or 2.

[0060] A specific example of a compound represented by formula (Y) is CF ２ = CFOCF ２ CF (CF ３ ) OCF ２ CF ２ CN (hereinafter also referred to as "8CNVE"), CF ２ = CFO (CF ２ ) ５ CN (hereinafter also referred to as "MV5CN"), CF ２ = CFOCF ２ CF ２ CF ２ OCF (CF ３ ) CN and CF ２ = CFO (CF ２ ) ３ CN is one example, and 8CNVE or MV5CN is preferred because they offer superior release properties and heat resistance for crosslinked rubber articles.

[0061] From the viewpoint of obtaining superior mold release properties and physical properties of crosslinked rubber articles, the content of monomers having cyano groups is preferably 0.5 to 20 mol%, more preferably 0.5 to 15 mol%, even more preferably 0.5 to 10 mol%, and particularly preferably 0.5 to 5 mol%, relative to the total amount of monomer A.

[0062] Monomers having at least one atom selected from the group consisting of chlorine, bromine, and iodine atoms include monomers having a bromine atom and monomers having an iodine atom. A specific example of a monomer having a bromine atom is CF ２ = CFOCF２ CF ２ CF ２ OCF ２ CF ２ Examples include Br, bromotrifluoroethylene, 4-bromo-3,3,4,4-tetrafluorobutene-1 (BTFB), vinyl bromide, 1-bromo-2,2-difluoroethylene, perfluoroallyl bromide, 4-bromo-1,1,2-trifluorobutene-1, 4-bromo-1,1,3,3,4,4-hexafluorobutene, 4-bromo-3-chloro-1,1,3,4,4-pentafluorobutene, 6-bromo-5,5,6,6-tetrafluorohexene, 4-bromoperfluorobutene-1,3,3-difluoroallyl bromide. Also, 2-bromo-perfluoroethyl perfluorovinyl ether, CF ２ Br-R ｆ -O -CF = CF ２ (R ｆ Fluorinated compounds such as perfluoroalkylene groups, for example, CF ２ BrCF ２ O - CF = CF ２ , ROCF=CFBr, ROCBr=CF ２ Fluorovinyl ethers such as CH (where R is a lower alkyl group or fluoroalkyl group), specifically CH ３ OCF = CFBr or CF ３ CH ２ OCF = CFBr is one example.

[0063] A specific example of a monomer containing an iodine atom is given by the formula: CHR = CH-Z-CH ２ CHR-I (wherein multiple Rs are independently -H or -CH) ３ Z is a linear or branched C, which may contain one or more ether oxygen atoms. １ ~C １８ Examples include iodized olefins of a (per)fluoroalkylene group, or a (per)fluoropolyoxyalkylene group as disclosed in U.S. Patent No. 5,674,959. Also, as disclosed in U.S. Patent No. 5,717,036, formula: I(CH ２ CF ２ CF ２ )ｎ OCF = CF ２ and ICH ２ CF ２ O[CF(CF ３ ) CF ２ O] ｎ CF = CF ２ Examples of unsaturated ethers include those specified in the formula (where n = 1 to 3). Also, as disclosed in U.S. Specification 4,694,045, examples include iodoethylene, 4-iodo-3,3,4,4-tetrafluorobutene-1 (ITFB), 3-chloro-4-iodo-3,4,4-trifluorobutene, 2-iodo-1,1,2,2-tetrafluoro-1-(vinyloxy)ethane, 2-iodo-1-(perfluorovinyloxy)-1,1,-2,2-tetrafluoroethylene, 1,1,2,3,3,3-hexafluoro-2-iodo-1-(perfluorovinyloxy)propane, 2-iodoethyl vinyl ether, 3,3,4,5,5,5-hexafluoro-4-iodopentene, and iodotrifluoroethylene. Additionally, examples include allyl iodide and 2-iodo-perfluoroethyl perfluorovinyl ether.

[0064] Specific examples of polymerizable unsaturated bonds in BO include carbon-carbon double bonds (C=C) and carbon-carbon triple bonds (C≡C). Carbon-carbon double bonds (C=C) are more preferred as polymerizable unsaturated bonds. The number of polymerizable unsaturated bonds in BO is preferably 2 to 6, more preferably 2 or 3, and even more preferably 2, from the viewpoint of superior polymerization reactivity. Furthermore, BO is preferably equipped with fluorine atoms from the viewpoint of reducing the compression set of the crosslinked rubber article at high temperatures.

[0065] BO is preferably a monomer represented by formula (B1) because it provides superior release properties for crosslinked rubber articles. (CR ２１ R ２２ =CR ２３ -) ａ１ R ２４ (B1) In formula (B1), R ２１ , R ２２ and R ２３Each of these is independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group, and a1 is an integer from 2 to 6, R ２４ This is a 1-valent perfluorohydrocarbon group having 1 to 10 carbon atoms, or a group having an etheric oxygen atom at the terminal or between carbon-carbon bonds of the perfluorohydrocarbon group, and a plurality of R ２１ , multiple R ２２ and multiple R ２３ Each of them may be the same or different from each other, but it is preferable that they be the same. a1 is preferably 2 or 3, and more preferably 2. From the viewpoint of superior polymerization reactivity of BO, R ２１ , R ２２ and R ２３ It is preferable that R is a fluorine atom or a hydrogen atom. ２１ , R ２２ and R ２３ It is more preferable that all of them are fluorine atoms or all of them are hydrogen atoms, as this provides better release properties for the crosslinked rubber article. ２１ , R ２２ and R ２３ It is even more preferable that all of them are fluorine atoms. ２４ The chain may be linear, branched, or annular, with linear or branched being preferred, and linear being more preferred. ２４ The number of carbon atoms is preferably 2 to 8, more preferably 3 to 7, even more preferably 3 to 6, and particularly preferably 3 to 5. ２４ It may or may not have etheric oxygen atoms, but it is preferable to have etheric oxygen atoms because it provides superior crosslinking reactivity and rubber properties. ２４ The number of etheric oxygen atoms in is preferably 1 to 6, more preferably 1 to 3, and even more preferably 1 or 2. ２４ The etheric oxygen atom in R ２４ It is preferable that it be located at the terminal end.

[0066] Among the monomers represented by formula (B1), suitable specific examples include the monomers represented by formula (B2) and the monomers represented by formula (B3). (CF ２ =CF-) ２R ３１ (B2) In formula (B2), R ３１ This refers to a divalent perfluorohydrocarbon group having 1 to 10 carbon atoms, or a group having an etheric oxygen atom at the terminal or between carbon-carbon bonds of the perfluorohydrocarbon group. (CH ２ =CH-) ２ R ４１ (B3) In equation (B3), R ４１ This refers to a divalent perfluorohydrocarbon group having 1 to 10 carbon atoms, or a group having an etheric oxygen atom at the terminal or between carbon-carbon bonds of the perfluorohydrocarbon group.

[0067] A concrete example of a monomer represented by formula (B2) is CF ２ = CFO (CF ２ ) ２ OCF = CF ２ CF ２ = CFO (CF ２ ) ３ OCF = CF ２ CF ２ = CFO (CF ２ ) ４ OCF = CF ２ CF ２ = CFO (CF ２ ) ６ OCF = CF ２、 CF ２ = CFO (CF ２ ) ８ OCF = CF ２ CF ２ = CFO (CF ２ ) ２ OCF (CF ３ ) CF ２ OCF = CF ２ CF ２ = CFO (CF ２ ) ２ O(CF(CF ３ ) CF ２ O) ２ CF = CF ２ CF ２ = CFOCF ２ O(CF) ２ CF ２ O) ２ CF = CF ２ CF ２= CFO (CF ２ O) ３ O(CF(CF ３ ) CF ２ O) ２ CF = CF ２ CF ２ = CFOCF ２ CF (CF ３ ) O (CF ２ ) ２ OCF (CF ３ ) CF ２ OCF = CF ２ , and CF ２ = CFOCF ２ CF ２ O(CF) ２ O) ２ CF ２ CF ２ OCF = CF ２ Examples include: Among the monomers represented by formula (B2), a more suitable specific example of a monomer is CF ２ = CFO (CF ２ ) ３ OCF = CF ２ (Hereinafter also referred to as "C3DVE"), and CF ２ = CFO (CF ２ ) ４ OCF = CF ２ (Hereafter, this will also be referred to as "C4DVE") is one example.

[0068] A concrete example of a monomer represented by formula (B3) is CH ２ =CH(CF ２ ) ２ CH=CH ２ ,CH ２ =CH(CF ２ ) ４ CH=CH ２ , and CH ２ =CH(CF ２ ) ６ CH=CH ２ Examples include CH ２ =CH(CF ２ ) ６ CH=CH ２ (Hereafter, this will also be referred to as "C6DV") is one example.

[0069] In particular, BO is preferably C3DVE or C4DVE.

[0070] - Chain Transfer Agent - In manufacturing method A, a chain transfer agent may be used. Examples of chain transfer agents include compounds having at least one selected from the group consisting of bromine atoms and iodine atoms. By using a compound having at least one selected from the group consisting of bromine atoms and iodine atoms as a chain transfer agent, at least one selected from the group consisting of bromine atoms and iodine atoms is introduced to the terminals of the fluorine-containing elastomer. Then, as described above, by using a solid composition containing a fluorine-containing elastomer having at least one selected from the group consisting of bromine atoms and iodine atoms, a PO-based crosslinked rubber having a hydrocarbon crosslinking structure can be obtained.

[0071] Examples of the above-mentioned chain transfer agent include the compound represented by formula (I). (Rf Ｉ ) - (X Ｉ ) ２ (I) In formula (I), Rf Ｉ X is a fluoroalkylene group having 1 to 16 carbon atoms, or an aromatic ring group. Ｉ Rf is an iodine atom or a bromine atom, and at least one of them is an iodine atom. Ｉ The fluoroalkylene group may be linear or branched. Ｉ A perfluoroalkylene group is preferred. Ｉ Ideally, all of them should be iodine atoms.

[0072] Compounds represented by formula (I) include 1,2-diiodoperfluoroethane, 1,3-diiodoperfluoropropane, 1,4-diiodoperfluorobutane (hereinafter also referred to as "perfluoro1,4-diiodobutane" or "C4DI"), 1,5-diiodoperfluoropentane, 1,6-diiodoperfluorohexane, 1,8-diiodoperfluoroctan, 1,3-diiodo-2-chloroperfluoropropane, 1,5-diiodo-2,4-dichloroperfluoropentane, 1,12-diiodoperfluorododecane, 1,16-diiodoperfluorohexadecane, and diiodome Examples include tan, 1,2-diiodoethane, 1,3-diiodo-n-propane, (2-iodoethyl) substituted derivatives of benzene, 1-iodo-4-bromoperfluorobutane, 1-iodo-6-bromoperfluorohexane, 1-iodo-8-bromoperfluoroctan, 1-bromo-2-iodoperfluoroethane, 1-bromo-3-iodoperfluoropropane, 2-bromo-3-iodoperfluorobutane, 3-bromo-4-iodoperfluorobutene-1, 2-bromo-4-iodoperfluorobutene-1, monoiodomonobromo substituted derivatives of benzene, and diiodomonobromo substituted derivatives. C4DI is preferred as the compound represented by formula (I).

[0073] When the fluorine-containing elastomer contains iodine atoms, the proportion of iodine atoms is preferably 0.01 to 5.00% by mass, more preferably 0.01 to 2.00% by mass, and even more preferably 0.01 to 1.00% by mass, relative to the total mass of the fluorine-containing elastomer.

[0074] -Polymerization Initiator- A polymerization initiator may be used in manufacturing method A. The polymerization initiator used in manufacturing method A is preferably a water-soluble polymerization initiator, more preferably persulfates such as ammonium persulfate, sodium persulfate, and potassium persulfate, more preferably organic polymerization initiators such as disuccinic acid peroxide and azobisisobutylamidine dihydrochloride, even more preferably persulfates, and particularly preferably ammonium persulfate. The amount of polymerization initiator used is preferably 0.01 to 5 parts by mass, more preferably 0.01 to 3 parts by mass, and even more preferably 0.01 to 2 parts by mass, per 100 parts by mass of monomer A. When a polymerization initiator is used, it may be added to the reactor all at once or in portions. When added in portions, it may be added in multiple stages or continuously.

[0075] -Polymerization conditions- The polymerization temperature is preferably 10 to 95°C, and more preferably 15 to 90°C. The polymerization pressure is preferably 0.5 to 4.0 MPaG, and more preferably 0.6 to 3.5 MPaG. The polymerization time is preferably 90 to 1000 minutes, and more preferably 90 to 800 minutes.

[0076] -Aqueous dispersion A- In manufacturing method A, for example, by carrying out a step of polymerizing monomer A, an aqueous dispersion A is obtained in which particles of the specific elastomer, which is a fluorine-containing elastomer, are dispersed in the aqueous medium.

[0077] The average particle diameter of the fluorine-containing elastomer particles dispersed in the aqueous dispersion A is preferably 500 nm or less, more preferably 300 nm or less, even more preferably 200 nm or less, and particularly preferably 150 nm or less, from the viewpoint of particle dispersion stability. The lower limit is preferably 2 nm or more, more preferably 5 nm or more, and even more preferably 10 nm or more. As the average particle diameter of the fluorine-containing elastomer particles, the particle diameter calculated by analyzing the autocorrelation function obtained by dynamic light scattering using the monodisperse cumulant method, or D50 (median diameter), can be used. The above D50 is the particle diameter at the point on the cumulative curve where the cumulative volume is 50%, obtained by measuring the particle size distribution by laser diffraction and scattering, setting the total volume of the particle collection to 100%, and measuring the cumulative curve. As a specific method for measuring the average particle diameter, the method of the examples described later can be used.

[0078] The solid content concentration of aqueous dispersion A is preferably 0.01 to 30% by mass. The solid content concentration of the dispersion can be calculated, for example, by heating 2.0 g of the dispersion at 170°C for 20 minutes, weighing the mass of the residue, and using the following formula: "Solid content concentration (mass%) = 100 × Heating residue of dispersion (g) / Mass of dispersion (2.0 g)"

[0079] Examples of aqueous dispersion A include an aqueous dispersion in which particles of a specific elastomer with an average particle size (primary particle size) of 1 to 300 nm are dispersed in an aqueous medium at a solid content concentration of 1 to 50% by mass.

[0080] It is preferable that the fluorine-containing elastomer does not have a melting point. "Having no melting point" means that when the melting point of the fluorine-containing elastomer is measured using a differential scanning calorimeter, no melting peak is observed. Specifically, this means that no melting peak is observed in the temperature range of 150°C or higher (preferably in the temperature range of 150°C to 330°C). Note that the glass transition peak does not fall under the category of a melting peak. Specific methods for measuring the melting point are shown in the Examples section.

[0081] The Tg of the fluorine-containing elastomer is +10.0°C or lower, for example, between -50.0°C and +10.0°C. From the viewpoint of low-temperature resistance, a Tg of +5.0°C or lower is preferred, and a Tg of +3.0°C or lower is more preferred. From the viewpoint of rubber properties, a Tg of -40.0°C or higher is preferred, a Tg of -30.0°C or higher is more preferred, and a Tg of -10.0°C or higher is even more preferred. The Tg of the fluorine-containing elastomer is measured by differential scanning calorimetry (DSC). Specific methods for measuring Tg are shown in the Examples section.

[0082] The fluorine-containing elastomer obtained by manufacturing method A is obtained by polymerizing monomer A. When compound (X) is used in manufacturing method A, compound (X) may or may not be copolymerized with monomer A. The fluorine-containing elastomer may or may not contain structural units based on compound (X).

[0083] The fluorine-containing elastomer obtained by manufacturing method A contains at least TFE units and / or VdF units. If monomer A further contains other monomers, the fluorine-containing elastomer obtained by manufacturing method A further contains constituent units based on the other monomers. Details of the other monomers are as described above. In addition to TFE units and / or VdF units, the fluorine-containing elastomer obtained by manufacturing method A preferably further contains at least one selected from the group consisting of PAVE units, P units, and HFP units. The fluorine-containing elastomer may have TFE units and PAVE units, or TFE units and P units, or TFE units, VdF units, and HFP units, or VdF units and HFP units. The fluorine-containing elastomer preferably contains TFE units and PAVE units.

[0084] When a fluorine-containing elastomer contains TFE units and PAVE units, the TFE unit content in the fluorine-containing elastomer is preferably 20 to 95 mol%, more preferably 25 to 85 mol%, and more preferably 35 to 75 mol%, relative to the total content of TFE units and PAVE units, in order to obtain superior rubber properties. The preferred ratio is the same when PAVE units are PMVE units (i.e., when the fluorine-containing elastomer contains both TFE units and PMVE units) and when PAVE units are PPVE units (i.e., when the fluorine-containing elastomer contains both TFE units and PPVE units).

[0085] When the fluorine-containing elastomer contains TFE units and P units, the TFE unit content in the fluorine-containing elastomer is preferably 10 to 95 mol%, more preferably 20 to 85 mol%, and more preferably 25 to 75 mol%, relative to the total content of TFE units and P units, from the viewpoint of superior rubber properties. When the fluorine-containing elastomer contains TFE units, VdF units and HFP units, the TFE unit content in the fluorine-containing elastomer is preferably 3 to 60 mol%, more preferably 3 to 50 mol%, and more preferably 3 to 40 mol%, relative to the total content of TFE units, VdF units, and HFP units, from the viewpoint of superior rubber properties. When a fluorine-containing elastomer has VdF units and HFP units, the VdF unit content in the fluorine-containing elastomer is preferably 5 to 90 mol%, more preferably 8 to 80 mol%, and more preferably 10 to 70 mol%, relative to the total content of VdF units and HFP units, in order to obtain superior rubber properties.

[0086] From the viewpoint of facilitating crosslinking, the fluorine-containing elastomer preferably has at least one selected from the group consisting of chlorine atoms, bromine atoms, iodine atoms, and cyano groups, and more preferably has at least one selected from the group consisting of bromine atoms, iodine atoms, and cyano groups.

[0087] The proportion of each constituent unit in the fluorine-containing elastomer and the fluorine-containing polymer described later is: １９ It is determined from F-NMR analysis and infrared absorption spectroscopy.

[0088] (Manufacturing Method B) Manufacturing Method B includes a step of polymerizing a first monomer containing TFE and / or VdF in a first aqueous medium to produce a first fluorine-containing polymer (hereinafter also referred to as the "first polymerization step"), and a step of polymerizing a second monomer containing TFE and / or VdF in an aqueous dispersion containing the first fluorine-containing polymer to obtain a fluorine-containing elastomer containing the first fluorine-containing polymer and the second fluorine-containing polymer (hereinafter also referred to as the "second polymerization step").

[0089] Manufacturing method B may include other steps as needed. Other steps include, for example, a purification step in which the dispersion containing the first fluorine-containing polymer obtained through the first polymerization step is purified, and a concentration adjustment step in which the solid content concentration of the dispersion containing the first fluorine-containing polymer is adjusted. In manufacturing method B, for example, after the first polymerization step, the process proceeds continuously, after the purification step and concentration adjustment step as needed, before proceeding to the second polymerization step. In manufacturing method B, for example, the first polymerization step, the purification step, the concentration adjustment step, and the second polymerization step are carried out in succession.

[0090] [First Polymerization Step] -Emulsifier- The first polymerization step of manufacturing method B may be carried out in the presence of an emulsifier containing fluorine atoms, or under conditions in which an emulsifier containing fluorine atoms is substantially absent. From the viewpoint of obtaining a solid composition with a faster crosslinking rate, it is preferable to carry out the step under conditions in which an emulsifier containing fluorine atoms is substantially absent. The first polymerization step is preferable to carry out under conditions in which an emulsifier is substantially absent from the viewpoint of obtaining a solid composition with a faster crosslinking rate. Examples of emulsifiers include the emulsifiers mentioned above. The statement that an emulsifier containing fluorine atoms is substantially absent means that in the first polymerization step, the content of the emulsifier containing fluorine atoms is 10 ppm by mass or less with respect to the total amount of the first aqueous medium, preferably 150 ppb by mass or less, and more preferably 50 ppb by mass or less. The lower limit is 0 ppb by mass. The term "substantially absent emulsifier" means that in the first polymerization step, the emulsifier content is 10 ppm by mass or less relative to the total amount of the first aqueous medium, preferably 150 ppb by mass or less, and more preferably 50 ppb by mass or less. The lower limit is 0 ppb by mass.

[0091] -First Aqueous Medium- The first polymerization step of manufacturing method B is carried out under conditions in which the first aqueous medium is present. Specific examples of the first aqueous medium are the same as the specific examples of the aqueous medium described above. In this disclosure, "before the polymerization of the first monomer used for polymerization of the first fluorine-containing polymer is started" means immediately before the start of polymerization. Here, "the start of polymerization" refers to the time when the first monomer is added to the reactor after the reactor has been heated to or above the polymerization temperature, and the time when the reactor has been heated to or above the polymerization temperature after the first monomer has been added to the reactor, etc.

[0092] - Compound (X) - The first aqueous medium preferably further contains compound (X). Preferred embodiments of compound (X) are as described above. When compound (X) is contained in the first aqueous medium, the dispersibility of the resulting first fluorine-containing polymer is improved, making polymerization easier, and a first fluorine-containing polymer with a high molecular weight and a large number of particles is obtained. Then, in the second polymerization step which is carried out continuously after the first polymerization step, the large number of particles of the first fluorine-containing polymer that serve as the polymerization site for the second monomer improves the dispersion stability of the second fluorine-containing polymer.

[0093] The amount of compound (X) added is preferably 0.1 to 5000 ppm by mass, more preferably 0.2 to 1000 ppm by mass, even more preferably 0.3 to 500 ppm by mass, and particularly preferably 0.5 to 100 ppm by mass, relative to the total amount of the first aqueous medium.

[0094] -First Monomer- In the first polymerization step of manufacturing method B, a first monomer containing TFE and / or VdF is polymerized. The first monomer may further contain the other monomers. Details of the other monomers are as described above. Preferably, the first monomer contains, in addition to TFE and / or VdF, at least one selected from the group consisting of PAVE, propylene, and HFP units. The first monomer may contain TFE and PAVE, TFE and propylene, TFE, VdF and HFP, or VdF and HFP. Preferably, the first monomer contains TFE and PAVE.

[0095] When monomer A contains TFE, the TFE content is preferably 10 to 90 mol%, more preferably 30 to 80 mol%, even more preferably 40 to 80 mol%, and particularly preferably 40 to 70 mol%, relative to the total amount of the first monomer. When the first monomer contains TFE and PAVE, the TFE content in the first monomer is preferably 20 to 95 mol%, more preferably 25 to 85 mol%, and more preferably 35 to 75 mol%, relative to the total content of TFE and PAVE, from the viewpoint of polymerization stability in the second polymerization step. When the first monomer contains TFE and PAVE, the total amount of TFE and PAVE used is preferably 80 to 99.9 mol%, more preferably 90 to 99.5 mol%, and even more preferably 95 to 99 mol%, relative to the amount of the first monomer used. The preferred proportions are the same when PMVE is used as PAVE (i.e., when the first monomer contains TFE and PMVE) and when PPVE is used as PAVE (i.e., when the first monomer contains TFE and PPVE).

[0096] When the first monomer contains TFE and propylene, the TFE content in the first monomer is preferably 10 to 95 mol%, more preferably 20 to 85 mol%, and more preferably 25 to 75 mol%, relative to the total content of TFE and propylene, from the viewpoint of polymerization stability in the second polymerization step. When the first monomer contains TFE and propylene, the total amount of TFE and propylene used is preferably 60 to 99.9 mol%, more preferably 70 to 99.5 mol%, and even more preferably 80 to 99 mol%, relative to the amount of the first monomer used.

[0097] When the first monomer contains TFE, VdF, and HFP, the TFE content in the first monomer is preferably 3 to 60 mol%, more preferably 3 to 50 mol%, and more preferably 3 to 40 mol%, relative to the total content of TFE, VdF, and HFP, from the viewpoint of polymerization stability in the second polymerization step. When the first monomer A contains TFE, VdF, and HFP, the total amount of TFE, VdF, and HFP used is preferably 80 to 99.9 mol%, more preferably 90 to 99.5 mol%, and even more preferably 95 to 99 mol%, relative to the amount of the first monomer used.

[0098] When the first monomer contains VdF and HFP, the VdF content in the first monomer is preferably 5 to 90 mol%, more preferably 8 to 80 mol%, and more preferably 10 to 70 mol%, relative to the total content of VdF and HFP, from the viewpoint of polymerization stability in the second polymerization step. When monomer A contains VdF and HFP, the total amount of VdF and HFP used is preferably 40 to 100 mol%, more preferably 50 to 100 mol%, and even more preferably 60 to 100 mol%, relative to the amount of monomer A used.

[0099] The first monomer may further contain the aforementioned crosslinking monomer. Details of the other monomers and crosslinking monomers are as described above.

[0100] - Chain transfer agent - In the first polymerization step of manufacturing method B, a chain transfer agent may be used. When the crosslinked rubber is a PO-based crosslinked product having a hydrocarbon crosslinked structure, the preferred embodiment of the chain transfer agent is as described above.

[0101] -Polymerization Initiator- In the first polymerization step of manufacturing method B, a polymerization initiator may be used. The preferred embodiment of the polymerization initiator is as described above. The amount of polymerization initiator used is preferably 0.01 to 5 parts by mass, more preferably 0.01 to 3 parts by mass, and even more preferably 0.01 to 2 parts by mass, per 100 parts by mass of the first monomer. When a polymerization initiator is used, it may be added to the reactor all at once or in portions. When added in portions, it may be added in multiple stages or continuously.

[0102] -Polymerization conditions- The polymerization temperature is preferably 10 to 95°C, and more preferably 15 to 90°C. The polymerization pressure is preferably 0.5 to 4.0 MPaG, and more preferably 0.6 to 3.5 MPaG.

[0103] -First Fluorine-containing Polymer- In the first polymerization step of manufacturing method B, for example, by carrying out a step of polymerizing the first monomer, a first aqueous dispersion containing the first fluorine-containing polymer is obtained. The first fluorine-containing polymer contains constituent units based on the first monomer. When compound (X) is used in the first polymerization step, compound (X) may or may not be copolymerized with the first monomer. The first fluorine-containing polymer may or may not contain constituent units based on compound (X).

[0104] The first fluorine-containing polymer preferably has no melting point. Having no melting point means that when the melting point of the first fluorine-containing polymer is measured using a differential scanning calorimeter, no melting peak is observed. Specifically, this means that no melting peak is observed in the temperature range of 150°C or higher (preferably in the temperature range of 150°C to 330°C). Note that the glass transition peak does not fall under the category of a melting peak. Specific methods for measuring the melting point are shown in the Examples section.

[0105] The first fluorine-containing polymer obtained in the first polymerization step of manufacturing method B contains at least TFE units and / or VdF units. If the first monomer further contains other monomers, the first fluorine-containing polymer further contains constituent units based on the other monomers. Details of the other monomers are as described above. In addition to TFE units and / or VdF units, the first fluorine-containing polymer preferably further contains at least one selected from the group consisting of PAVE units, P units, and HFP units. The first fluorine-containing polymer may have TFE units and PAVE units, or TFE units and P units, or TFE units, VdF units, and HFP units, or VdF units and HFP units. It is preferable that the first fluorine-containing polymer contains TFE units and PAVE units.

[0106] When the first fluorine-containing polymer contains TFE units and PAVE units, the content of TFE units in the first fluorine-containing polymer is preferably 20 to 95 mol%, more preferably 25 to 85 mol%, and more preferably 35 to 75 mol%, relative to the total content of TFE units and PAVE units, from the viewpoint of polymerization stability in the second polymerization step. The preferred proportions are the same when PAVE units are PMVE units (i.e., when the first fluorine-containing polymer contains TFE units and PMVE units) and when PAVE units are PPVE units (i.e., when the first fluorine-containing polymer contains TFE units and PPVE units). When the first fluorine-containing polymer contains TFE units and P units, the content of TFE units in the first fluorine-containing polymer is preferably 10 to 95 mol%, more preferably 20 to 85 mol%, and more preferably 25 to 75 mol%, relative to the total content of TFE units and P units, from the viewpoint of polymerization stability in the second polymerization step. When the first fluorine-containing polymer contains TFE units, VdF units, and HFP units, the content of TFE units in the first fluorine-containing polymer is 3 to 60 mol%, preferably 3 to 50 mol%, and more preferably 3 to 40 mol%, based on the total content of TFE units, VdF units, and HFP units, from the viewpoint of polymerization stability in the second polymerization step. When the first fluorine-containing polymer contains VdF units and HFP units, the content of VdF units in the first fluorine-containing polymer is 5 to 90 mol%, preferably 8 to 80 mol%, and more preferably 10 to 70 mol%, based on the total content of VdF units and HFP units, from the viewpoint of polymerization stability in the second polymerization step.

[0107] [Purification Step] In the purification step, which may be included in manufacturing method B as needed, the first aqueous dispersion containing the first fluorine-containing polymer obtained through the first polymerization step is subjected to a purification treatment. In the purification step, the first aqueous dispersion obtained through the first polymerization step may be subjected to the purification treatment directly, or the solid content concentration of the first aqueous dispersion may be adjusted by the concentration adjustment step described later before the purification treatment is performed. Manufacturing method B is preferable in that it makes it easier to obtain a second fluorine-containing polymer with desired physical properties. In other words, it is preferable to use the aqueous dispersion after the purification treatment in the above purification step to perform polymerization of the second monomer in the second polymerization step. By going through the purification step, impurities such as polymerization initiators and their decomposition products can be removed, making it easier to obtain a fluorine-containing elastomer with desired physical properties. Examples of purification methods include heat treatment and removal using an ion exchange resin, and a method of contacting the aqueous dispersion to be purified with an ion exchange resin is preferred.

[0108] As the ion exchange resin, a cation exchange resin or an anion exchange resin is preferred. The amount of ion exchange resin used is preferably 1 to 100 parts by mass, and more preferably 1 to 50 parts by mass, per 100 parts by mass of the aqueous dispersion to be purified. Specific examples of methods for contacting the aqueous dispersion to be purified with the ion exchange resin include mixing the aqueous dispersion to be purified with the ion exchange resin or passing the aqueous dispersion to be purified through a column packed with the ion exchange resin. The purification process may be performed multiple times.

[0109] [Concentration Adjustment Step] In the concentration adjustment step, which may be included in manufacturing method B as needed, the solid content concentration of the aqueous dispersion containing the first fluorine polymer may be adjusted. In the concentration adjustment step, for example, at least one of the following is performed on the first aqueous dispersion obtained by the first polymerization step or the aqueous dispersion that has undergone the purification step: removal of an aqueous medium and addition of an aqueous medium. In the concentration adjustment step, the solid content concentration may be adjusted by removing only a portion of the aqueous medium contained in the aqueous dispersion, or solvent substitution may be performed by removing the aqueous medium contained in the aqueous dispersion and adding another aqueous medium. When an aqueous medium is added in the concentration adjustment step, the added aqueous medium may be the same type of aqueous medium as the first aqueous medium, or it may be a different type of aqueous medium.

[0110] [Second Polymerization Step] In the second polymerization step of manufacturing method B, a second monomer containing TFE is polymerized in an aqueous dispersion containing the first fluorine-containing polymer to obtain a fluorine-containing elastomer containing the first fluorine-containing polymer and the second fluorine-containing polymer.

[0111] -Aqueous Dispersion- The aqueous dispersion used in the second polymerization step may be the first aqueous dispersion after the first polymerization step as is, or the first aqueous dispersion after the first polymerization step may have undergone at least one of a purification step and a concentration adjustment step. It is preferable to use an aqueous dispersion in which the first aqueous dispersion after the first polymerization step has undergone at least a purification step, as this makes it easier to obtain a second fluorine-containing polymer with desired physical properties.

[0112] The content of the first fluorine-containing polymer is preferably 0.01 to 10.0% by mass relative to the total amount of the aqueous dispersion, and more preferably 0.01 to 5.0% by mass, as this allows for more efficient production of the second fluorine-containing polymer. In particular, it is preferable that the above range is met before the polymerization of the second monomer begins.

[0113] The aqueous dispersion preferably contains a second aqueous medium. Specific examples of the second aqueous medium are the same as those for the first aqueous medium. The type of the second aqueous medium may be the same as or different from that of the first aqueous medium.

[0114] Before the polymerization of the second monomer begins, the aqueous dispersion may contain other components besides those described above. Specific examples of other components that the aqueous dispersion may contain include chain transfer agents, reducing agents, and pH adjusters. Specific examples of chain transfer agents include ethyl acetate, methanol, ethanol, t-butyl methyl ether, diethyl ether, n-pentane, cyclohexane, methane, 1,4-diiodoperfluorobutane, and propane. Specific examples of pH adjusters include inorganic salts and ammonia. Specific examples of inorganic salts include phosphates such as disodium hydrogen phosphate and sodium dihydrogen phosphate, and carbonates such as sodium bicarbonate and sodium carbonate. More preferred examples of phosphates include disodium hydrogen phosphate dihydrate and disodium hydrogen phosphate dodecahydrate.

[0115] If the aqueous dispersion contains a chain transfer agent, the content of the chain transfer agent is preferably 0.1 to 5 parts by mass per 100 parts by mass of the second aqueous medium. If the aqueous dispersion contains a pH adjusting agent, the content of the pH adjusting agent is preferably 0.01 to 3.0 parts by mass per 100 parts by mass of the second aqueous medium.

[0116] -Second Monomer- The second monomer comprises TFE and / or VdF. The second monomer may further contain the other monomers. Details of the other monomers are as described above. Preferably, the second monomer comprises, in addition to TFE and / or VdF, at least one selected from the group consisting of PAVE, propylene, and HFP units. The second monomer may contain TFE and PAVE, TFE and propylene, TFE, VdF and HFP, or VdF and HFP. Preferably, the second monomer contains TFE and PAVE.

[0117] When the second monomer contains TFE, the TFE content is preferably 10 to 90 mol%, more preferably 30 to 80 mol%, even more preferably 40 to 80 mol%, and particularly preferably 40 to 70 mol%, relative to the total amount of the second monomer. When the second monomer contains TFE and PAVE, the TFE content in the second monomer is preferably 20 to 95 mol%, more preferably 25 to 85 mol%, and more preferably 35 to 75 mol%, relative to the total content of TFE and PAVE, from the viewpoint of superior polymerization reactivity. When the second monomer contains TFE and PAVE, the total amount of TFE and PAVE used is preferably 80 to 99.9 mol%, more preferably 90 to 99.5 mol%, and even more preferably 95 to 99 mol%, relative to the amount of the second monomer used. The preferred proportions are the same when PMVE is used as PAVE (i.e., when the second monomer contains TFE and PMVE) and when PPVE is used as PAVE (i.e., when the second monomer contains TFE and PPVE).

[0118] When the second monomer contains TFE and propylene, the TFE content in the second monomer is preferably 10 to 95 mol%, more preferably 20 to 85 mol%, and more preferably 25 to 75 mol%, relative to the total content of TFE and propylene, in order to obtain superior polymerization reactivity. When the second monomer contains TFE and propylene, the total amount of TFE and propylene used is preferably 60 to 99.9 mol%, more preferably 70 to 99.5 mol%, and even more preferably 80 to 99 mol%, relative to the amount of the second monomer used.

[0119] When the second monomer contains TFE, VdF, and HFP, the TFE content in the second monomer is preferably 3 to 60 mol%, more preferably 3 to 50 mol%, and more preferably 3 to 40 mol%, relative to the total content of TFE, VdF, and HFP, from the viewpoint of superior polymerization reactivity. When the second monomer contains TFE, VdF, and HFP, the total amount of TFE, VdF, and HFP used is preferably 80 to 99.9 mol%, more preferably 90 to 99.5 mol%, and even more preferably 95 to 99 mol%, relative to the amount of the second monomer used.

[0120] When the second monomer contains VdF and HFP, the VdF content in the second monomer is preferably 5 to 90 mol%, more preferably 8 to 80 mol%, and more preferably 10 to 70 mol%, relative to the total content of VdF and HFP, from the viewpoint of superior polymerization reactivity. When the second monomer contains VdF and HFP, the total amount of VdF and HFP used is preferably 40 to 100 mol%, more preferably 50 to 100 mol%, and even more preferably 60 to 100 mol%, relative to the amount of the second monomer used.

[0121] The second monomer may further contain the aforementioned crosslinking monomer. Details of the other monomers and crosslinking monomers are as described above. The amount of the second monomer used is preferably 1 to 60 parts by mass, more preferably 5 to 50 parts by mass, and even more preferably 10 to 40 parts by mass, per 100 parts by mass of the second aqueous medium.

[0122] - Chain transfer agent - In the second polymerization step of manufacturing method B, a chain transfer agent may be used. When the crosslinked rubber is a PO-based crosslinked product having a hydrocarbon crosslinked structure, the preferred embodiment of the chain transfer agent is as described above.

[0123] -Polymerization Initiator- In the second polymerization step of manufacturing method B, a polymerization initiator may be used. The preferred embodiment of the polymerization initiator is as described above. The amount of polymerization initiator used is preferably 0.01 to 5 parts by mass, more preferably 0.01 to 3 parts by mass, and even more preferably 0.01 to 2 parts by mass, per 100 parts by mass of the amount of the second monomer used. When a polymerization initiator is used, it may be added to the reactor all at once or in portions. When added in portions, it may be added in multiple stages or continuously.

[0124] -Polymerization conditions- The polymerization temperature is preferably 10 to 95°C, and more preferably 15 to 90°C. The polymerization pressure is preferably 0.5 to 4.0 MPaG, and more preferably 0.6 to 3.5 MPaG. The polymerization time is preferably 90 to 1000 minutes, and more preferably 90 to 800 minutes.

[0125] -Emulsifier- The second polymerization step of manufacturing method B is preferably carried out under conditions in which the emulsifier having fluorine atoms is substantially absent. The second polymerization step of manufacturing method B is more preferably carried out under conditions in which the emulsifier is substantially absent. Examples of emulsifiers include the emulsifiers described above. The phrase "substantially absent emulsifier having fluorine atoms" means that in the second polymerization step, the content of the emulsifier having fluorine atoms is 10 ppm by mass or less, preferably 150 ppb by mass or less, and more preferably 50 ppb by mass or less, relative to the total amount of the second aqueous medium. The lower limit is 0 ppb by mass. The phrase "substantially absent emulsifier" means that in the second polymerization step, the content of the emulsifier is 10 ppm by mass or less, relative to the total amount of the second aqueous medium, preferably 150 ppb by mass or less, and more preferably 50 ppb by mass or less. The lower limit is 0 ppb by mass.

[0126] -Second Fluorine-containing Polymer- In the second polymerization step of manufacturing method B, particles containing the second fluorine-containing polymer are produced. Specifically, the method for producing the second fluorine-containing polymer yields a second aqueous dispersion in which particles containing the second fluorine-containing polymer are dispersed in the aqueous medium. The second fluorine-containing polymer contains structural units based on the second monomer. That is, the second fluorine-containing polymer contains TFE units and / or VdF units. If the second monomer further contains other monomers, the second fluorine-containing polymer further contains structural units based on the other monomers. Details of the other monomers are as described above. Preferably, the second fluorine-containing polymer further contains at least one selected from the group consisting of PAVE units, P units, and HFP units, in addition to TFE units and / or VdF units. The second fluorine-containing polymer may have TFE units and PAVE units, or TFE units and P units, or TFE units, VdF units, and HFP units, or VdF units and HFP units. The second fluorine-containing polymer preferably contains TFE units and PAVE units. When the second fluorine-containing polymer has TFE units and PAVE units, the content of TFE units in the second fluorine-containing polymer is preferably 20 to 95 mol%, more preferably 25 to 85 mol%, and more preferably 35 to 75 mol%, relative to the total content of TFE units and PAVE units, from the viewpoint of superior rubber properties. The preferred ratio is the same when PAVE units are PMVE units (i.e., when the second fluorine-containing polymer contains TFE units and PMVE units) and when PAVE units are PPVE units (i.e., when the second fluorine-containing polymer contains TFE units and PPVE units).

[0127] When the second fluorine-containing polymer contains TFE units and P units, the content of TFE units in the second fluorine-containing polymer is preferably 10 to 95 mol%, more preferably 20 to 85 mol%, and more preferably 25 to 75 mol%, relative to the total content of TFE units and P units, from the viewpoint of superior rubber properties. When the second fluorine-containing polymer contains TFE units, VdF units and HFP units, the content of TFE units in the second fluorine-containing polymer is preferably 3 to 60 mol%, more preferably 3 to 50 mol%, and more preferably 3 to 40 mol%, relative to the total content of TFE units, VdF units, and HFP units, from the viewpoint of superior rubber properties. When the second fluorine-containing polymer has VdF units and HFP units, the VdF unit content in the second fluorine-containing polymer is preferably 5 to 90 mol%, more preferably 8 to 80 mol%, and more preferably 10 to 70 mol%, relative to the total content of VdF units and HFP units, in order to obtain superior rubber properties.

[0128] -Second aqueous dispersion- By carrying out the second polymerization step of manufacturing method B, a fluorine-containing elastomer containing the first fluorine-containing polymer and the second fluorine-containing polymer is obtained. After the second polymerization step of manufacturing method B, for example, a second aqueous dispersion is obtained in which particles of the fluorine-containing elastomer containing the first fluorine-containing polymer and the second fluorine-containing polymer are dispersed in a second aqueous medium.

[0129] In the second aqueous dispersion, the first fluorine-containing polymer and the second fluorine-containing polymer exist in the form of particles. The first fluorine-containing polymer and the second fluorine-containing polymer may exist separately in the second aqueous dispersion, but it is preferable that they exist in the form of particles containing both the first and second fluorine-containing polymers, and more preferably in the form of particles consisting of the first and second fluorine-containing polymers (i.e., particles of the specific elastomer, which is a fluorine-containing elastomer).

[0130] In this case, the average particle size of the fluorine-containing elastomer particles is more preferably 400 nm or less, even more preferably 350 nm or less, and particularly preferably 300 nm or less. The lower limit is preferably 10 nm or more, more preferably 30 nm or more, and even more preferably 50 nm or more. The method for measuring the average particle size of the particles is as described above.

[0131] The solid content concentration of the second aqueous dispersion is preferably 0.01 to 30% by mass. The method for measuring the solid content concentration of the dispersion is as described above.

[0132] Examples of the second aqueous dispersion include an aqueous dispersion in which particles of a specific elastomer having an average particle size (primary particle size) of 1 to 300 nm are dispersed in an aqueous medium at a solid content concentration of 1 to 50% by mass.

[0133] The fluorine-containing elastomer obtained by manufacturing method B contains at least TFE units and / or VdF units. The fluorine-containing elastomer may further contain constituent units based on the other monomers. Details of the other monomers are as described above. Preferably, the fluorine-containing elastomer obtained by manufacturing method B contains, in addition to TFE units and / or VdF units, at least one selected from the group consisting of PAVE units, P units, and HFP units. The fluorine-containing elastomer obtained by manufacturing method B may have TFE units and PAVE units, or TFE units and P units, or TFE units, VdF units, and HFP units, or VdF units and HFP units. Preferably, the fluorine-containing elastomer obtained by manufacturing method B contains TFE units and PAVE units.

[0134] When the fluorine-containing elastomer obtained by manufacturing method B contains TFE units and PAVE units, the TFE unit content in the fluorine-containing elastomer is preferably 20 to 95 mol%, more preferably 25 to 85 mol%, and more preferably 35 to 75 mol%, relative to the total content of TFE units and PAVE units, in order to obtain superior rubber properties. The preferred ratio is the same when PAVE units are PMVE units (i.e., when the fluorine-containing elastomer contains TFE units and PMVE units) and when PAVE units are PPVE units (i.e., when the fluorine-containing elastomer contains TFE units and PPVE units).

[0135] When the fluorine-containing elastomer contains TFE units and P units, the TFE unit content in the fluorine-containing elastomer is preferably 10 to 95 mol%, more preferably 20 to 85 mol%, and more preferably 25 to 75 mol%, relative to the total content of TFE units and P units, from the viewpoint of superior rubber properties. When the fluorine-containing elastomer contains TFE units, VdF units and HFP units, the TFE unit content in the fluorine-containing elastomer is preferably 3 to 60 mol%, more preferably 3 to 50 mol%, and more preferably 3 to 40 mol%, relative to the total content of TFE units, VdF units, and HFP units, from the viewpoint of superior rubber properties. When a fluorine-containing elastomer has VdF units and HFP units, the VdF unit content in the fluorine-containing elastomer is preferably 5 to 90 mol%, more preferably 8 to 80 mol%, and more preferably 10 to 70 mol%, relative to the total content of VdF units and HFP units, in order to obtain superior rubber properties.

[0136] The fluorine-containing elastomer obtained by manufacturing method B preferably has at least one selected from the group consisting of chlorine atoms, bromine atoms, iodine atoms, and cyano groups, and more preferably has at least one selected from the group consisting of bromine atoms, iodine atoms, and cyano groups, from the viewpoint of facilitating crosslinking. Similarly, as mentioned above, the fluorine-containing elastomer obtained by manufacturing method A also preferably has at least one selected from the group consisting of chlorine atoms, bromine atoms, iodine atoms, and cyano groups, and more preferably has at least one selected from the group consisting of bromine atoms, iodine atoms, and cyano groups, from the viewpoint of facilitating crosslinking.

[0137] The fluorine-containing elastomer obtained by manufacturing method B preferably has no melting point. Similarly, as mentioned above, the fluorine-containing elastomer obtained by manufacturing method A also preferably has no melting point. Specific methods for measuring the melting point are shown in the examples section. The Tg of the fluorine-containing elastomer obtained by manufacturing method B is +10.0°C or lower, and the preferred range of Tg and the measurement method are the same as those for the fluorine-containing elastomer obtained by manufacturing method A.

[0138] <Agglutination Process> In the agglutination process, a liquid aqueous solution containing water and having a temperature of Tg or lower is brought into contact with the aqueous dispersion prepared in the aqueous dispersion preparation process, causing the particles of the specific elastomer to aggregate at an agglutination temperature of Tg + 5.0°C or lower. This yields a solid composition containing aggregates of the specific elastomer particles. From the viewpoint of maintaining a low agglutination temperature, a method of dropping one of the liquid aqueous solution and the aqueous dispersion onto the other is preferred for contacting the liquid aqueous solution and the aqueous dispersion. If the freezing point of the aqueous dispersion is Tg + 5.0°C or lower, in the agglutination process, the aqueous dispersion may be dropped onto the liquid aqueous solution, or the liquid aqueous solution may be dropped onto the aqueous dispersion. On the other hand, if the freezing point of the aqueous dispersion is higher than Tg + 5.0°C, as will be described later, from the viewpoint of maintaining an agglutination temperature of Tg + 5.0°C or lower, it is preferable to drop the aqueous dispersion onto the liquid dispersion. Below, as an example of the agglutination process, an agglutination process in which the liquid aqueous solution and the aqueous dispersion are brought into contact by dropping the aqueous dispersion onto the liquid dispersion will be described.

[0139] (Liquid aqueous solution) A liquid aqueous solution is an aqueous solution that contains water and is liquid at its condensation temperature. Preferably, the liquid aqueous solution further contains components other than water. In particular, when the condensation temperature is 0.0°C or lower, the above liquid aqueous solution, which is liquid at its condensation temperature, contains components other than water. Examples of components other than water include alcohols, inorganic salts, acids, bases, and combinations thereof.

[0140] Examples of alcohols include methanol, ethanol, propanol, and t-butanol. The number of carbon atoms in the alcohol can be, for example, 1 to 4, with 1 to 3 being preferred and 1 to 2 more preferred from the viewpoint of lowering the freezing point of the liquid aqueous solution. From the viewpoint of lowering the freezing point of the liquid aqueous solution, alcohols with 1 to 4 carbon atoms and a boiling point of less than 100°C are preferred. Examples of inorganic salts include ammonium carbonate, calcium chloride, potassium chloride, aluminum potassium sulfate, ammonium acetate, ammonium nitrate, ammonium phosphate, ammonium chloride, and ammonium sulfate. From the viewpoint of reducing the metal content of the elastomer, ammonium carbonate, ammonium acetate, ammonium nitrate, ammonium phosphate, ammonium chloride, and ammonium sulfate are preferred inorganic salts. Examples of acids include nitric acid, hydrochloric acid, sulfuric acid, oxalic acid, and hydrofluoric acid. From the viewpoint of reducing the metal content of the elastomer, nitric acid and sulfuric acid are preferred acids. Examples of bases include potassium hydroxide, calcium hydroxide, and ammonia.

[0141] The liquid aqueous solution preferably contains at least one selected from the group consisting of alcohols, inorganic salts, and acids, more preferably contains at least one selected from the group consisting of alcohols and inorganic salts, and even more preferably contains alcohols and inorganic salts. When the liquid aqueous solution contains alcohol, the alcohol content relative to the total liquid aqueous solution can be, for example, 1 to 60% by mass, and from the viewpoint of lowering the freezing point of the liquid aqueous solution, 5 to 60% by mass is preferred, and 10 to 60% by mass is more preferred. When the liquid aqueous solution contains inorganic salt, the inorganic salt content relative to the total liquid aqueous solution can be, for example, 2 to 4% by mass, and from the viewpoint of reducing the amount of fine particles of fluorine-containing elastomer generated, 2 to 3% by mass is preferred, and 2 to 2.5% by mass is more preferred. When the liquid aqueous solution contains acid, the acid content relative to the total liquid aqueous solution can be, for example, 1 to 60% by mass, and from the viewpoint of lowering the freezing point of the liquid aqueous solution and the cleanability of the solid composition obtained by aggregation, 1.2 to 50% by mass is preferred, and 1.5 to 40% by mass is more preferred.

[0142] Temperature T of the aqueous solution before adding the aqueous dispersion dropwise. １ The temperature is below Tg, and from the viewpoint of maintaining the condensation temperature below Tg + 5.0°C, it is preferably lower than Tg, more preferably below Tg - 1.0°C, and even more preferably below Tg - 5.0°C. １ The lower limit of this limit is the freezing point of a liquid aqueous solution.

[0143] (Aqueous dispersion) If the aqueous dispersion preparation step includes a polymerization step, the dispersion obtained in the polymerization step (for example, the aforementioned aqueous dispersion A, second aqueous dispersion, etc.) may be used as the aqueous dispersion in the coagulation step, or a dispersion with adjusted solid content may be used as necessary. Temperature T of the aqueous dispersion before dropping in the coagulation step ２ The temperature of the aqueous dispersion should be above the freezing point, and is preferably low from the viewpoint of maintaining the coagulation temperature below Tg + 5.0°C. ２ Examples include Tg + 40.0°C or lower, with Tg + 30.0°C being preferred.

[0144] (Aggregation conditions) Aggregation temperature T ３ Tg is the maximum temperature of the liquid aqueous solution during the coagulation process. For example, if the freezing point of the aqueous dispersion is higher than Tg + 5.0°C, the temperature of the aqueous dispersion must be kept Tg in order to maintain the liquid state of the aqueous dispersion. ２ The temperature needs to be higher than Tg + 5.0°C. In that case, the temperature of the aqueous solution to which the aqueous dispersion is added is the temperature before mixing T １ It becomes higher than the aggregation temperature T. ３ A method for maintaining the temperature below Tg + 5.0°C is, for example, the aggregation temperature T ３ A temperature lower than T １ One method involves using a liquid aqueous solution, adding an aqueous dispersion dropwise while stirring the liquid aqueous solution, and slowing down the dropping rate of the aqueous dispersion. Coagulation temperature T ３ The temperature is Tg + 5.0°C or lower, and from the viewpoint of obtaining a solid composition with a fast crosslinking rate, it is preferably lower than Tg, more preferably Tg - 2.0°C or lower, and even more preferably Tg - 5.0°C or lower. ３ The lower limit of this limit is the freezing point of a liquid aqueous solution.

[0145] The dropping time for the aqueous dispersion (i.e., the time from the start of dropping to the completion of dropping) can be, for example, 5 to 120 minutes, and from the viewpoint of productivity and control of the coagulation temperature, 15 to 60 minutes is preferred. The amount of aqueous dispersion to be dropped can be, for example, 20 to 100 parts by mass per 100 parts by mass of liquid aqueous solution, and from the viewpoint of suppressing wastewater volume while improving washing performance, 40 to 70 parts by mass is preferred. As described above, in the coagulation step, the aqueous dispersion may be dropped while stirring the liquid aqueous solution. The stirring speed can be, for example, 92 to 400 rpm, and from the viewpoint of obtaining a solid composition with a fast crosslinking rate, 200 to 400 rpm is preferred. The coagulation time (i.e., the time from the completion of dropping to separation) can be, for example, 1 to 60 minutes, and from the viewpoint of increasing the coagulation rate while maintaining productivity, 5 to 20 minutes is preferred.

[0146] In the aggregation process, aggregates of specific elastomer particles are formed in a liquid aqueous solution. The volume median particle size D50B of the aggregates in the liquid aqueous solution can be, for example, 50 to 500 μm. From the viewpoint of obtaining a solid composition with a fast crosslinking rate, the volume median particle size D50B of the aggregates in the liquid aqueous solution is preferably 400 μm or less, more preferably 300 μm or less, and even more preferably 200 μm or less. From the viewpoint of handling, the volume median particle size D50B of the aggregates in the liquid aqueous solution is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 20 μm or more. The volume median particle size D50B of the aggregates in the liquid aqueous solution is measured using an in-situ particle size analyzer. Specific methods for measuring the volume median particle size D50B are shown in the Examples section.

[0147] The volume-average particle size D50A of the aggregates constituting the solid composition separated from the liquid aqueous solution at a coagulation temperature of ±5.0°C can be, for example, 50 to 500 μm. The volume-average particle size D50A of the aggregates is a value measured after separating the solid composition containing aggregates of specific elastomer particles obtained in the coagulation process from the liquid aqueous solution at a coagulation temperature of ±5.0°C. From the viewpoint of obtaining a solid composition with a fast crosslinking rate, the volume-average particle size D50A of the aggregates is preferably 250 μm or less, more preferably 150 μm or less, and even more preferably 100 μm or less. The volume-average particle size D50A of the aggregates is measured by grain boundary analysis using image analysis software. Specific methods for measuring the volume-average particle size D50A are shown in the Examples section.

[0148] <Other steps> This manufacturing method may further include other steps such as a separation step for separating a solid composition containing aggregates of specific elastomer particles obtained by the aggregation step from a liquid aqueous solution, and a washing step for washing the solid composition separated from the liquid aqueous solution with a washing liquid. An example of the separation step is filtration. An example of the washing liquid used in the washing step is water.

[0149] [Solid Composition] <First Embodiment> The solid composition according to the first embodiment of this disclosure (hereinafter also referred to as "Solid Composition A") contains a fluorine-containing elastomer (the specified elastomer mentioned above) which includes a constituent unit based on TFE and / or VdF and has a Tg of +10.0°C or less, and at least one selected from the group consisting of a compound (S1) represented by formula (S1) and a compound (S2) represented by formula (S2), wherein the total content of the compound (S1) and the compound (S2) in relation to the entire solid composition is less than 250 ppb by mass. H(CF ２ ) ｐ１ COOM １ (S1) H(CF ２ ) ｐ２ SO ３ M ２ (S2) In equations (S1) and (S2), M １ and M ２ Each is independently a hydrogen atom, Na, K, or NH ４ Therefore, p1 is an integer between 3 and 13, and p2 is an integer between 4 and 10.

[0150] Hereinafter, the total content of compound (S1) in the solid composition will also be referred to as the "(S1) content," and the total content of compound (S2) in the solid composition will also be referred to as the "(S2) content." Solid composition A is obtained by the manufacturing method described above. The sum of the (S1) content and the (S2) content of solid composition A is within the range described above. Therefore, when crosslinked rubber articles are manufactured using solid composition A, the crosslinking reaction of the specific elastomer is less likely to be inhibited in the crosslinking process, and the crosslinking rate is expected to be faster. Details of the specific elastomer contained in solid composition A are as described above.

[0151] (Total content of (S1) and (S2)) The total content of (S1) and (S2) in solid composition A is greater than 0 ppb by mass and less than 250 ppb by mass. From the viewpoint of improving the crosslinking rate in the solid composition, the total content of (S1) and (S2) is preferably 200 ppb by mass or less, more preferably 150 ppb by mass or less, even more preferably 100 ppb by mass or less, particularly preferably 50 ppb by mass or less, and extremely preferably 30 ppb by mass or less. The total content of (S1) and (S2) in solid composition A may be 5 ppb by mass or more, 10 ppb by mass or more, or 15 ppb by mass or more.

[0152] <Second Embodiment> The solid composition according to the second embodiment of the present disclosure (hereinafter also referred to as "Solid Composition B") contains aggregates of particles containing a fluorine-containing elastomer (the aforementioned specific elastomer) which includes constituent units based on TFE and / or VdF and has a Tg of +10.0°C or less, and the volume average particle size D50A of the aggregates is 500 μm or less.

[0153] Solid composition B is obtained by the manufacturing method described above. Since the volume-average particle size D50A of the aggregates contained in solid composition B is within the aforementioned range, components other than the particles of the specific elastomer are less likely to be incorporated into the aggregates, and the emulsifier content is considered to be low. Therefore, when crosslinked rubber articles are manufactured using solid composition B, the crosslinking reaction of the specific elastomer is less likely to be inhibited in the crosslinking process, and the crosslinking rate is considered to be faster. Details of the specific elastomer contained in solid composition B are as described above.

[0154] (Volume-average particle size D50A) The volume-average particle size D50A of the aggregates contained in solid composition B is 500 μm or less, for example, 50 to 500 μm. From the viewpoint of improving the crosslinking rate, the volume-average particle size D50A of the aggregates contained in solid composition B is preferably 250 μm or less, more preferably 150 μm or less, and even more preferably 100 μm or less. The volume-average particle size D50A of the aggregates contained in solid composition B is measured by grain boundary analysis using image analysis software. Specific methods for measuring the volume-average particle size D50A are shown in the Examples section.

[0155] <Third Embodiment> The solid composition according to the third embodiment of the present disclosure (hereinafter also referred to as "solid composition C") contains a fluorine-containing elastomer (the specified elastomer mentioned above) which includes a constituent unit based on TFE and / or VdF and has a Tg of +10.0°C or less, and does not contain compound (S1), compound (S2), compound (S3) represented by formula (S3), compound (S4) represented by formula (S4), compound (S5) represented by formula (S5), compound (S6) represented by formula (S6), compound (S7) represented by formula (S7), compound (S8) represented by formula (S8), compound (S9) represented by formula (S9), and compound (S10) represented by formula (S10), or contains at least one selected from the group consisting of compounds (S1) to (S10), and the total content of compounds (S1) to (S10) is less than 250 ppb by mass relative to the solid composition.

[0156] H(CF) ２ ) ｐ１ COOM １ (S1) H(CF ２ ) ｐ２ SO ３ M ２ (S2) F(CF) ２ ) ｐ３ COOM ３ (S3) F(CF) ２ ) ｐ４ SO ３ M ４ (S4) X ５１ (CF ２ ) ｐ５ (OCF ２ CF ２ CF ２ ) ｑ５ OCF(X ５２ ) CF ２ COOM ５ (S5) X ６１ (CF ２ ) ｐ６ (OCF(X ６２ ) CF(X ６３ )) ｑ６ OCF(X ６４ ) COOM ６ (S6) X ７１ (CF ２ )ｐ７ CF(X ７２ ) (OCF(X ７３ ) CF(X ７４ )) ｑ７ OCF(X ７５ ) COOM ７ (S7)

[0157]

[0158] X １０１ CF ２ (OCF ２ CF ２ ) ｑ１０ (OCF ２ ) ｒ１０ X １０２ (S10) In formulas (S1) to (S10), M １ ~M ９ Each is independently a hydrogen atom, Na, K, or NH ４ X ５１ , X ６１ , X ７１ , X ８１ , X ８２ , X ９１ , and X ９２ Each of these is independently a hydrogen atom, a fluorine atom, or a chlorine atom, and X １０１ and X １０２ Each of these is independently a hydrogen atom, a fluorine atom, a COOH group, or a chlorine atom, and X １０１ and X １０２ At least one of them is COOH, X ５２ , X ６２ ~X ６４ , and X ７２ ~X ７５ Each of these is independently a hydrogen atom, a fluorine atom, or a perfluoroalkyl group having 1 to 3 carbon atoms, and Rf ８ ~Rf ９ Each is independently a fluorine-containing alkylene group having 1 to 20 carbon atoms, p1 and p3 are independently integers from 3 to 13, p2 and p4 are independently integers from 4 to 10, p5 to p7 are independently integers from 1 to 10, q5 to q7 are independently integers from 0 to 3, q8 to q9 are independently integers from 1 to 20, n8 to n9 are independently integers from 1 to 30, and q8 and n8 are the CF of compound (S8). ２A combination of integers such that the number of elements is 30 or less, where q9 and n9 are the CFs of the compound (S9). ２ The integer combination is such that the number of groups is 30 or less, q10 and r10 are each independent integers of 0 or greater, and q10 and r10 are integer combinations such that the number-average molecular weight of the compound (S10) is between 300 and 1000.

[0159] Hereinafter, at least one compound selected from the group consisting of compounds (S1) to (S10) will also be referred to as "compound (A)," and the total content of compound (A) in the solid composition will also be referred to as "compound (A) content." Solid composition C is obtained by the manufacturing method described above. Solid composition C has a compound (A) content within the above range. Therefore, when a crosslinked rubber article is manufactured using solid composition C, the crosslinking reaction of the specific elastomer is less likely to be inhibited in the crosslinking process, and the crosslinking rate is expected to be faster. Details of the specific elastomer contained in solid composition C are as described above.

[0160] (Compound (A) content) The compound (A) content in solid composition C is 0 ppb by mass, or greater than 0 ppb by mass and less than 250 ppb by mass. From the viewpoint of improving the crosslinking rate in the solid composition, the compound (A) content is preferably 200 ppb by mass or less, more preferably 150 ppb by mass or less, even more preferably 100 ppb by mass or less, particularly preferably 50 ppb by mass or less, and extremely preferably 30 ppb by mass or less. If solid composition C contains compound (A), the compound (A) content may be 5 ppb by mass or more, 10 ppb by mass or more, or 15 ppb by mass or more. It may be 5 mass ppb or more and less than 250 mass ppb, 5 mass ppb or more and 200 mass ppb or less, 5 mass ppb or more and 150 mass ppb or less, 5 mass ppb or more and 100 mass ppb or less, 5 mass ppb or more and 50 mass ppb or less, 5 mass ppb or more and 30 mass ppb or less, 10 mass ppb or more and 50 mass ppb or less, or 10 mass ppb or more and 30 mass ppb or less.

[0161] <Fourth Embodiment> The solid composition according to the fourth embodiment of this disclosure (hereinafter also referred to as "solid composition D") contains a fluorine-containing elastomer (the specified elastomer mentioned above) which includes a constituent unit based on TFE and / or VdF and has a Tg of +10.0°C or lower, and one or more CF ２ It has a group and one or more ionic functional groups, wherein the ionic functional groups are COOM, SO ３ M, PO ４ M, or SO ４ M is a hydrogen atom, Na, K, or NH ４ The CF per ionic functional group ２ When compound (B) is defined as a compound having 30 or fewer groups, lacking carbon-carbon double bonds and carbon-carbon triple bonds, and having a number-average molecular weight of 3000 or less, the composition either does not contain compound (B) or contains compound (B) with a total content of compound (B) of less than 250 ppb by mass relative to the entire solid composition.

[0162] Hereinafter, the total content of compound (B) in the solid composition will also be referred to as the "compound (B) content." Solid composition D is obtained by the manufacturing method described above. The compound (B) content of solid composition D is within the range described above. Therefore, when crosslinked rubber articles are manufactured using solid composition D, the crosslinking reaction of the specific elastomer is less likely to be inhibited in the crosslinking process, and the crosslinking rate is expected to be faster. Details of the specific elastomer contained in solid composition D are as described above.

[0163] (Compound (B) content) The compound (B) content in solid composition D is 0 ppb by mass, or greater than 0 ppb by mass and less than 250 ppb by mass. From the viewpoint of improving the crosslinking rate in the solid composition, the compound (B) content is preferably 200 ppb by mass or less, more preferably 150 ppb by mass or less, even more preferably 100 ppb by mass or less, particularly preferably 50 ppb by mass or less, and extremely preferably 30 ppb by mass or less. If solid composition D contains compound (B), the compound (B) content may be 5 ppb by mass or more, 10 ppb by mass or more, or 15 ppb by mass or more. It may be 5 mass ppb or more and less than 250 mass ppb, 5 mass ppb or more and 200 mass ppb or less, 5 mass ppb or more and 150 mass ppb or less, 5 mass ppb or more and 100 mass ppb or less, 5 mass ppb or more and 50 mass ppb or less, 5 mass ppb or more and 30 mass ppb or less, 10 mass ppb or more and 50 mass ppb or less, or 10 mass ppb or more and 30 mass ppb or less.

[0164] (Compound (B)) Compound (B) is, as described above, 1 or more CF ２ It has a group and one or more ionic functional groups, and the CF per ionic functional group ２ A compound having 30 or fewer groups, lacking carbon-carbon double bonds and carbon-carbon triple bonds, and having a number-average molecular weight of 3000 or less. Ionic functional groups include COOM and SO. ３ M, PO ４ M, or SO ４ M is a hydrogen atom, Na, K, or NH ４ Among these, the ionic functional groups are COOM or SO ３ M is preferred, and COOM is more preferred. The number of ionic functional groups in one molecule can be, for example, 1 to 2, and 1 is preferred. CF per ionic functional group ２ The number of groups is 30 or less, may be 25 or less, 20 or less, 13 or less, or 10 or less. Also, the CF per ionic functional group ２The number of elements is 1 or more, may be 2 or more, may be 3 or more, or may be 4 or more.

[0165] Specific examples of compound (B) include, for example, compounds (S1) to (S10). Furthermore, as a specific example of compound (B), the ionic functional groups of compounds (S1) to (S10) are PO ４ M, or SO ４ The compounds changed to M, and the ionic functional groups of compounds (S5) to (S10) were changed to SO ３ Compounds modified to M are also examples. The number-average molecular weight of compound (B) may be 300 to 3000 or 300 to 1000.

[0166] The following describes matters common to solid composition A, solid composition B, solid composition C, and solid composition D. Furthermore, the term "this solid composition" may be used as a collective term for solid composition A, solid composition B, solid composition C, and solid composition D. This solid composition only needs to be at least one selected from the group consisting of solid composition A, solid composition B, solid composition C, and solid composition D, and may also correspond to any of the embodiments described above.

[0167] <Total Content of Metal Elements> From the viewpoint of suppressing contamination of the surrounding area during use, it is preferable that this solid composition does not contain metal elements, or contains metal elements, with the total content of metal elements being greater than 0 ppm by mass and 10 ppm by mass or less relative to the solid composition. Hereinafter, the total content of metal elements relative to the entire solid composition will also be referred to as the "metal content". From the viewpoint of suppressing contamination of the surrounding area during use, the metal content is preferably 10 ppm by mass or less, more preferably 5 ppm by mass or less, and even more preferably 2 ppm by mass or less. If this solid composition contains metal elements, the metal content may be 0.3 ppm by mass or more.

[0168] The metal content is determined by placing the solid composition to be measured in a platinum crucible, ashing it in a high-temperature electric heating furnace, treating it with sulfuric acid fumes, and then measuring the resulting solution using an inductively coupled plasma mass spectrometer. Specifically, the content of 29 metal elements (Fe, Na, K, Li, Be, Mg, Al, Ca, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, Rb, Sr, Zr, Mo, Ag, Cd, In, Sn, Cs, Ba, Pb, Bi) is measured using the absolute calibration curve method, and the total value is defined as the above-mentioned metal content.

[0169] Methods for controlling the metal content in this solid composition to the aforementioned range include, for example, not using or using components containing metal elements in small amounts during the manufacturing process of the solid composition. Specifically, for example, in the process of agglomerating particles of fluorine-containing elastomer, a method can be used in which a metal-free flocculant (e.g., nitric acid) is used instead of a metal-containing flocculant (e.g., potassium aluminum sulfate) as the flocculant.

[0170] <Storage Modulus G'> The storage modulus G' of this solid composition is preferably 10 to 1000 kPa, more preferably 200 to 600 kPa, and even more preferably 250 to 550 kPa. By having a storage modulus below the above upper limit, the decrease in moldability due to a decrease in the fluidity of the fluorine-containing elastomer during the crosslinking reaction is suppressed. By having a storage modulus above the above lower limit, the decrease in moldability due to a deterioration in mold release properties after heat press molding is suppressed. The storage modulus is an indicator of the average molecular weight; a high value indicates a large molecular weight, and a low value indicates a small molecular weight. In this disclosure, the storage modulus is defined as the storage modulus at a frequency of 50 cpm and 100°C.

[0171] <5% Mass Thermogravimetric Loss Temperature> The 5% mass thermogravimetric loss temperature of this solid composition is preferably 350°C or higher, more preferably 375°C or higher, and even more preferably 400°C or higher, from the viewpoint of suppressing the generation of decomposition products that can contaminate the surrounding environment when used at high temperatures. From the viewpoint of rubber properties, the 5% mass thermogravimetric loss temperature of this solid composition is preferably 600°C or lower. The 5% mass thermogravimetric loss temperature can be measured, for example, using a thermogravimetric analyzer. Specific methods for measuring the 5% mass thermogravimetric loss temperature are shown in the Examples section.

[0172] <Applications> This solid composition is used in the manufacture of crosslinked rubber articles. Crosslinked rubber articles are obtained by mixing this solid composition with additives such as crosslinking agents and fillers as needed, and then molding and crosslinking it as needed. Examples of crosslinked structures that the crosslinked rubber contained in the crosslinked rubber articles may have include heterocyclic crosslinked structures, hydrocarbon crosslinked structures, ether group-mediated crosslinked structures, amino group-mediated crosslinked structures, etc.

[0173] Crosslinked rubber articles containing crosslinked rubber having a heterocyclic crosslinked structure (i.e., CN-based crosslinked material) are manufactured, for example, using a solid composition containing a fluorine-containing elastomer having cyano groups and a crosslinking agent.

[0174] Specific examples of crosslinking agents include compounds having two or more amino groups (hereinafter also referred to as "polyamine compounds"), organic peroxides, organic ammonia generating compounds that produce ammonia upon heating, and organotin compounds such as allenyl-tin curing agents. Polyamine compounds are preferred as crosslinking agents, and compounds having two amino groups are more preferred, as they exhibit excellent crosslinking properties for fluorine-containing elastomers and yield crosslinked rubber articles with lower compression set.

[0175] The polyamine compound may be a compound in which a hydrogen atom of an aliphatic hydrocarbon is substituted with an amino group, or a compound in which a hydrogen atom of an aromatic hydrocarbon is substituted with an amino group. However, a compound in which a hydrogen atom of an aromatic hydrocarbon is substituted with an amino group is preferred because it exhibits superior rubber properties. The polyamine compound preferably contains a fluorine atom. This improves compatibility with fluorine-containing copolymers, resulting in a crosslinked rubber article with lower compression set at high temperatures.

[0176] Specific examples of polyamine compounds include hexamethylenediamine, hexamethylenediamine carbamate, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis(3-amino-4-hydroxyphenyl)propane, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (hereinafter also referred to as "BOAP," also known as bisaminophenol AF), 2,2-bis(3,4-diaminophenyl)propane, 2,2-bis(3,4-diaminophenyl)hexafluoropropane, 2,2-bis(3-amino-4-(N-phenylamino)phenyl)hexafluoropropane, 4,4'-methylenedianiline, m-phenylenediamine, adipic acid dihydrazide, and the compound represented by formula (XII) of Japanese Patent No. 5833657, with BOAP being preferred.

[0177] A crosslinked rubber article containing a crosslinked rubber having a hydrocarbon crosslinking structure (i.e., a PO-based crosslinked material) is manufactured, for example, using a solid composition containing a fluorine-containing elastomer having at least one atom selected from the group consisting of chlorine atoms, bromine atoms, and iodine atoms, an organic peroxide which is a crosslinking agent, and a crosslinking aid.

[0178] As for the crosslinking agent, an organic peroxide with a half-life of 1 minute at a temperature of 100 to 250°C is preferred. Specific examples of organic peroxides include di-tert-butyl peroxide, tert-butylcumyl peroxide, dicumyl peroxide, α,α-bis(tert-butylperoxy)-p-diisopropylbenzene, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane-3, and other dialkyl peroxides, 1,1-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 2,5-dimethylhexane-2,5-dihydroxyperoxide, benzoyl peroxide, tert-butylperoxybenzene, 1,3-bis(tert-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, tert-butylperoxymaleic acid, and tert-butylperoxysopropyl carbonate. Among these, dialkyl peroxides are preferred. The amount of crosslinking agent added is preferably 0.3 to 10 parts by mass, more preferably 0.3 to 5 parts by mass, and most preferably 0.5 to 3 parts by mass, per 100 parts by mass of fluorine-containing elastomer. Within this range, the resulting crosslinked rubber article will have an excellent balance of strength and elongation.

[0179] Specific examples of crosslinking aids include triallyl cyanurate, triallyl isocyanurate (hereinafter also referred to as "TAIC"), trimetallyl isocyanurate, 1,3,5-triacryloylhexahydro-1,3,5-triazine, triallyl trimellitate, m-phenylenediamine bismaleimide, p-quinone dioxime, p,p'-dibenzoylquinone dioxime, dipropargyl terephthalate, diallyl phthalate, N,N',N'',N'''-tetraallyl terephthalamide, vinyl group-containing siloxane oligomers (polymethylvinylsiloxane, polymethylphenylvinylsiloxane, etc.). Among these, triallyl cyanurate, TAIC, and trimetallyl isocyanurate are preferred, with TAIC being more preferred. The amount of crosslinking aid is preferably 0.1 to 10 parts by mass, and more preferably 0.5 to 5 parts by mass, per 100 parts by mass of fluorine-containing elastomer. Within this range, the resulting cross-linked rubber articles will have an excellent balance of strength and elongation.

[0180] A crosslinked rubber article containing a crosslinked rubber having a crosslinked structure via an ether group is manufactured, for example, using a fluorine-containing elastomer having VdF units and a polyol compound as a crosslinking agent. A crosslinked rubber article containing a crosslinked rubber having a crosslinked structure via an amino group is manufactured, for example, using a fluorine-containing elastomer having VdF units and a polyamine compound as a crosslinking agent.

[0181] Crosslinked rubber articles manufactured using this solid composition are suitable for materials such as O-rings, sheets, gaskets, oil seals, diaphragms, and V-rings. In particular, they are preferably used as components for semiconductor manufacturing equipment, and more preferably as sealing materials for semiconductor material manufacturing equipment.

[0182] The present invention will be described in detail below with reference to examples. Examples A1 to A6, A8, and B1 are examples, and examples A7, A9, and B2 are comparative examples. However, the present invention is not limited to these examples.

[0183] [Measurement Methods and Evaluation Methods] The various measurement and evaluation methods are as follows.

[0184] <Average Particle Size> The aqueous dispersions of each example described below were degassed at 25°C for 5 minutes, pressurized with nitrogen gas to 0.2 MPaG, purged, and returned to atmospheric pressure to obtain the measurement samples. The average particle size of the obtained measurement samples was measured using a dynamic light scattering particle size distribution analyzer (Otsuka Electronics Co., Ltd., ELSZ) with the number of integration cycles set to 100, and this was taken as the average particle size of the particles in each aqueous dispersion.

[0185] <Solid Content Concentration> After heating 2.0 g of the aqueous dispersion of each example described below at 170°C for 20 minutes, the mass (g) of the residue is weighed, and the solid content concentration is calculated using the following formula: Solid Content Concentration (mass%) = 100 × (mass of residue) / (mass of aqueous dispersion (2.0 g))

[0186] <Volume median particle size D50B of aggregates in liquid aqueous solution> The volume median particle size D50B of aggregates in liquid aqueous solution was measured using an in-situ particle size analyzer (Mettler Toledo, product name: Particle Track) as follows: In the step of adding the aqueous dispersion prepared in the aqueous dispersion preparation step to a liquid aqueous solution containing water to aggregate particles of the specific elastomer, a probe-type electronic scanner was immersed in the liquid within 2 minutes from the start of dropping the aqueous dispersion to read the code length of the particles, and the obtained values ​​were integrated to obtain the volume median particle size D50B. The upper limit of detection for volume median particle size D50B is 1000 μm.

[0187] <Volume-average particle size D50A of aggregates contained in the solid composition> The volume-average particle size D50A of aggregates contained in the solid composition was measured as follows. While maintaining a low temperature so that the solid composition did not exceed Tg + 5.0°C, the filtered aggregates were transferred to a glass petri dish, and an image of the aggregates was obtained using an optical microscope (Keyence, product name: VK-X1100). Grain boundary analysis was performed on this image using the image analysis software ImageJ (method in accordance with JIS Z 8827-1), and the volume-average particle size was determined.

[0188] <Proportion of each constituent unit> The proportion of each constituent unit in a fluorine-containing polymer or fluorine-containing elastomer is: １９ The results were obtained from F-NMR analysis and infrared absorption spectroscopy.

[0189] <Melting Point> A 5 ​​mg sample of the obtained fluorine-containing polymer or fluorine-containing elastomer was weighed into an aluminum pan and heated from 20°C to 360°C in an air atmosphere at a heating rate of 10°C / min using a Hitachi DSC600, and the presence or absence of a melting peak was confirmed.

[0190] <Glass Transition Temperature (Tg)> Tg was measured using a NEXTA DSC600 manufactured by Hitachi High-Tech Corporation. Specifically, 5 mg of the sample for measurement was weighed into an aluminum sample pan, and the sample was heated to 100°C at a heating rate of 10°C / min under a nitrogen atmosphere. Then, it was cooled to -60°C at a rate of 10°C / min. Once the desired temperature was reached, it was heated again to 100°C at a rate of 10°C / min. Tg was estimated from the inflection point confirmed during this second heating operation.

[0191] <Measurement Method for Each Compound Contained in the Solid Composition> (Preparation of Measurement Sample) The solid compositions obtained in each of the examples described below were freeze-milled using a freeze mill 6775 (manufactured by SPEX) under the following conditions. Before freeze-milling, 10% by mass of dibutylhydroxytoluene (BHT) was added to the total mass of the solid composition to obtain a pulverized powder. The freeze-milling conditions were: solid composition: 3 g, BHT: 0.3 g, Run time: 5 min, Rate: 15 cps, Cycle: 3. 2.5 g of the obtained pulverized powder was mixed with 5 mL of methanol and subjected to sonication at 50°C for 2 hours. Centrifugation (5000 rpm, 5 min) was performed to settle each fluorine-containing elastomer, and the supernatant was used as the extract. The obtained extract was measured by LC / MS / MS. Compounds (S1), (S2), (A), or (B) in the extract (hereinafter collectively referred to as "each compound") were measured using a liquid chromatograph-mass spectrometer. The instrument configuration and LC-MS measurement conditions are shown in Table 1. Using aqueous solutions of each compound with known concentrations, methanol solutions with five or more levels of concentration were prepared. LC / MS analysis was performed on the methanol solutions at each concentration level, and the relationship between the concentration and the area area corresponding to that concentration was plotted to create a calibration curve. Using the above calibration curve, the area area of ​​the LC / MS chromatogram of each compound in the extract was converted to the concentration of each compound.

[0192]

[0193] The MRM measurement parameters are appropriately selected according to the structure of each compound to be measured. The parameters of MRM can use literature values or can also be calculated by an LC-MS apparatus. When determining the MRM parameters with an LC-MS apparatus, it is specifically as follows. Select the search for product ions using an LC / MS apparatus (Shimadzu Corporation, LCMS-8060NX), input the molecular weight of each compound to be measured, and perform precursor ion, precursor adjustment, voltage optimization, and optimization of product m / z. Use the calculated MRM measurement parameters. As an example, the MRM measurement parameters of compounds (S1) to (S4) are shown in Tables 2 to 5. Regarding the content of compound (S1) contained in each extract, for each compound where p1 = 3 to 13 in formula (S1), it was determined by converting to a perfluorocarboxylic acid (compound (S2)) having the same number of carbon atoms. Regarding the content of compound (S3) contained in each extract, for each compound where p3 = 4 to 10 in formula (S3), it was determined by converting to a perfluorosulfonic acid (compound (S4)) having the same number of carbon atoms.

[0194]

[0195]

[0196]

[0197]

[0198] (Quantification of Each Compound Contained in the Solid Composition) Specifically, first, five levels of methanol standard solutions of each compound with known concentrations of 1 to 180 ng / g were prepared respectively. From each sample concentration and the integral value of the peak, using linear approximation, a was determined by formula (A1). A = a × X (A1) A: Peak area of each compound, X: Concentration of each compound (ng / g)

[0199] Subsequently, the amounts of each compound contained in the extract were calculated using formula (A2). Here, a in formula (A2) means the a obtained by the above formula (A1). X Cm = A Cm / a (A2) X Cm: Content of the compound in each extract (ng / g) A Cm: Peak area of the compound in each extract The limit of quantification in this measurement is 1 ng / g.

[0200] In the solid composition, the content (Z Cm) of each compound with respect to the total mass of the solid composition was determined by the following formula (A3). Z Cm = X Cm × ρ1 × La / W1 (A3) Z Cm: Content of each compound contained in the solid composition ρ1: Density of the extraction solvent (methanol in each example) La: Volume of the extraction solvent (5 mL in each example) W1: Mass of the sample used for extraction (2.5 g of pulverized powder in each example)

[0201] From the values of Z Cm of each compound, the total of the contents of (S1) and (S2), the content of compound (A), and the content of compound (B) in the solid composition were determined respectively.

[0202] <Metal content>A measurement sample obtained by cutting the solid composition into an appropriate size was placed in a platinum crucible and ashed in a high-temperature electric heating furnace, and then sulfuric acid white smoke treatment was performed. Thereafter, it was dissolved in dilute nitric acid. For the solution dissolved in dilute nitric acid, the total content of 29 kinds of metal elements (Fe, Na, K, Li, Be, Mg, Al, Ca, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, Rb, Sr, Zr, Mo, Ag, Cd, In, Sn, Cs, Ba, Pb, Bi) was measured by the absolute calibration curve method using an inductively coupled plasma mass spectrometer (ICP-MS 7500cs manufactured by Agilent Technologies).

[0203] <5 mass% thermogravimetric reduction temperature>10 mg of the obtained solid composition was weighed into an aluminum pan, and using Hitachi STA200, it was heated from 40 °C to 550 °C at a heating rate of 10 °C / min in an air atmosphere, and the 5% thermogravimetric reduction temperature was obtained from the resulting weight reduction rate.

[0204] <Storage Modulus> A rubber processability analyzer, "PREMIER RPA (manufactured by Alpha Technologies, die shape: D0380)," was used as the measuring device. The solid compositions obtained in each example were kneaded for 10 minutes at room temperature (25°C) using two rolls to produce a 3 mm thick sheet. The sheet thickness was adjusted by adjusting the gap between the two rolls. The obtained sheet was cut to a weight of approximately 10 g to obtain a cut sheet. The cut sheet was sandwiched between two polyester films (ALFA Technologies PART #F0311-S, 130 mm × 130 mm × 24 μm) to obtain a sample for measurement. The sample was placed on the die of the above measuring device. The die temperature was pre-set to 100°C. Next, the sample was held for 2 minutes under the conditions of 100°C, frequency 30 cpm, and amplitude angle 0.2 deg. Then, the amplitude angle was changed to 0.5 deg, and the storage modulus was measured by increasing the frequency to 10 cpm, 20 cpm, 50 cpm, 100 cpm, 200 cpm, 500 cpm, 1000 cpm, and 2000 cpm. The storage modulus at a frequency of 50 cpm and 100°C was defined as the storage modulus G' (unit: kPa) of the sample.

[0205] <Crosslinking rate t ９０ > The crosslinking rate was measured as follows. Using each solid composition obtained in each example, a crosslinking rate evaluation composition with the composition shown in Table 6 below was prepared and kneaded for 10 minutes at 23°C using two rolls. After kneading, the gap between the two rolls was adjusted to obtain a 3 mm thick sheet for crosslinking rate evaluation. In the table below, each component and its abbreviation are as follows. Also, "-" in the table means that the corresponding component is not present. ・CB: MT carbon N990, manufactured by Vanderbilt Co., Ltd. ・Crosslinking aid: TAIC-WH60, manufactured by Mitsubishi Chemical, triallyl isocyanurate 60% silica diluted product ・Release agent: Nonsal SN-1, manufactured by NOF Corporation, sodium stearate ・Crosslinking agent 1: Perhexa 25B, manufactured by NOF Corporation, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane ・Crosslinking agent 2: 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (BOAP)

[0206]

[0207] The obtained sheet for evaluating the crosslinking rate was cut to a size of 10 g to obtain a cut sheet. The cut sheet was sandwiched between two polyester films (ALFA Technologies, PART #F0311-S, 130 mm × 130 mm × 24 μm) on both sides of the main surface to obtain a sample for measurement. The torque (dNm) of the sample was measured using a measuring device: PREMIER RPA (Alfa Technologies) under the conditions shown in Table 7 below. The processing time t90 was defined as the torque value at which the torque value reached 90% when the minimum torque value obtained was set to 0% and the maximum torque value was set to 100%.

[0208]

[0209] [Example A1] <Aqueous dispersion preparation process> Ultrapure water (1206 g), a 50% by mass aqueous solution of sodium 2-acrylamido-2-methyl-1-propanesulfonate (NaAAMPS, corresponding to "compound (X)") (30 μL, 15 mg of NaAAMPS), PMVE (82 g), and TFE (17 g) were added to a 2.1 L stainless steel pressure reactor, and the temperature was raised to 80°C while stirring at 600 rpm. The reactor pressure at 80°C was 1.4 MPaG. Next, an aqueous solution of ammonium persulfate (2.5% by mass, 7 g) was added and polymerization was started. As polymerization started, the pressure inside the reactor decreased, so TFE was added to maintain a constant pressure. This was repeated, and when the amount of TFE added after polymerization started reached 17 g, perfluoro-1,4-diiodobutane (C4DI, 1.08 g) and 7 g of PMVE were injected under pressure. Thereafter, 7 g of PMVE was injected each time 8 g of TFE was injected. When the amount of TFE added after polymerization had started reached 265 g, the addition of TFE and PMVE injected after polymerization had started was stopped, the reactor temperature was cooled to 10°C to stop the polymerization reaction, the remaining gas in the reactor was recovered, and the liquid was drained to obtain an aqueous dispersion A-A1 containing particles of fluorine-containing elastomer A1.

[0210] The total amount of monomers added before polymerization began was 17 g of TFE and 82 g of PMVE. The total amount of monomers added after polymerization began was 265 g of TFE and 217 g of PMVE. The total amount of TFE added was 282 g, and the total amount of PMVE added was 299 g. The average particle size of the fluorine-containing elastomer A1 particles in aqueous dispersion A-A1 was 102.3 nm, and the solid content concentration of aqueous dispersion A-A1 was 28.0% by mass.

[0211] <Agglomeration Process> A liquid aqueous solution A1 was prepared containing 60% by mass of methanol and 2% by mass of ammonium carbonate. The temperature of liquid aqueous solution A1 was T １ The temperature is -10.0℃, and the temperature of aqueous dispersion A-A1 is T ２ Each solution was cooled to +20.0°C, and aqueous dispersion A-A1 was added dropwise to liquid aqueous solution A1 over a dropping time of 20 minutes while stirring liquid aqueous solution A1 at the stirring speed shown in Table 8. The amount of aqueous dispersion added per 100 parts by mass of liquid aqueous solution was 38.4 parts by mass. The coagulation time is shown in Table 8. The coagulation temperature T was measured using a K-type thermocouple. ３ Table 8 shows the volume median particle size D50B of the aggregates in the liquid aqueous solution measured by the method described above. Note that the aggregation temperature T ３ This is the highest temperature reached when measuring the temperature of the liquid aqueous solution while adding an aqueous dispersion dropwise to the liquid aqueous solution.

[0212] <Measurement and Evaluation> The solid composition A1, consisting of aggregates of the obtained fluorine-containing elastomer A1, was separated from the liquid aqueous solution A1 by filtration while maintaining the aggregation temperature at ±5.0°C. The fluorine-containing elastomer A1 contained in the obtained solid composition A1 was analyzed by NMR and found to have a PMVE / TFE ratio of 35 / 65 (molar ratio). Furthermore, the fluorine-containing elastomer A1 did not have a melting point. The Tg of the fluorine-containing elastomer A1 is shown in Table 8. The volume-average particle size D50A, specific surface area, bulk density, total content of (S1) and (S2), compound (A) content, compound (B) content, metal content, 5% mass thermal weight loss temperature, and storage modulus of the obtained solid composition A1 were measured by the method described above. The results are shown in Table 8. The crosslinking rate of the obtained solid composition A1 was measured by the method described above. The results are shown in Table 8.

[0213] [Example A2] <Aqueous dispersion preparation step> The aqueous dispersion A-A1 obtained in Example A1 was used.

[0214] <Agglomeration Process> A liquid aqueous solution A2 was prepared containing 60% by mass of methanol and 4% by mass of ammonium carbonate. The temperature of liquid aqueous solution A2 was T １ The temperature is -10.0℃, and the temperature of aqueous dispersion A-A1 is T ２ Each solution was cooled to +25.0°C, and aqueous dispersion A-A1 was added dropwise to liquid aqueous solution A2 over a dropping time of 30 minutes while stirring at the stirring speed shown in Table 8. The amount of aqueous dispersion added per 100 parts by mass of liquid aqueous solution was 38.4 parts by mass. The coagulation time (time from the start of dropping to the completion of dropping) is shown in Table 8. The coagulation temperature T was measured using a K-type thermocouple. ３ Table 8 shows the volume median particle size D50B of the aggregates in the liquid aqueous solution measured by the method described above.

[0215] <Measurement and Evaluation> The solid composition A2, consisting of aggregates of the obtained fluorine-containing elastomer A1, was separated from the liquid aqueous solution A2 by filtration while maintaining the aggregation temperature at ±5.0°C. The volume-average particle size D50A, specific surface area, bulk density, total content of (S1) and (S2), compound (A) content, compound (B) content, metal content, 5% mass thermal weight loss temperature, and storage modulus of the obtained solid composition A2 were measured by the method described above. The results are shown in Table 8. The crosslinking rate of the obtained solid composition A2 was measured by the method described above. The results are shown in Table 8.

[0216] [Example A3] <Aqueous dispersion preparation step> The aqueous dispersion A-A1 obtained in Example A1 was used.

[0217] <Agglomeration Process> A liquid aqueous solution A3 containing 20% ​​by mass of nitric acid was prepared. The temperature of liquid aqueous solution A3 was T １ The temperature is -12.0°C, and the temperature of aqueous dispersion A-A1 is T ２ Each solution was cooled to +7.0°C, and aqueous dispersion A-A1 was added dropwise to liquid aqueous solution A3 over a period of 40 minutes while stirring at the stirring speed shown in Table 8. The amount of aqueous dispersion added per 100 parts by mass of liquid aqueous solution was 38.4 parts by mass. The coagulation time (time from the start of dropping to the completion of dropping) is shown in Table 8. The coagulation temperature T was measured using a K-type thermocouple. ３ Table 8 shows the volume median particle size D50B of the aggregates in the liquid aqueous solution measured by the method described above.

[0218] <Measurement and Evaluation> The solid composition A3, consisting of aggregates of the obtained fluorine-containing elastomer A1, was separated from the liquid aqueous solution A3 by filtration while maintaining the aggregation temperature at ±5.0°C. The volume-average particle size D50A, specific surface area, bulk density, total content of (S1) and (S2), compound (A) content, compound (B) content, metal content, 5% mass thermal weight loss temperature, and storage modulus of the obtained solid composition A3 were measured by the method described above. The results are shown in Table 8. The crosslinking rate of the obtained solid composition A3 was measured by the method described above. The results are shown in Table 8.

[0219] [Example A4] <Aqueous dispersion preparation step> The aqueous dispersion A-A1 obtained in Example A1 was used.

[0220] <Agglomeration Process> A liquid aqueous solution A4 containing 20% ​​by mass of nitric acid was prepared. The temperature of liquid aqueous solution A4 was T １ The temperature is -12.0°C, and the temperature of aqueous dispersion A-A1 is T ２ Each solution was cooled to +7.7°C, and aqueous dispersion A-A1 was added dropwise to liquid aqueous solution A4 over a dropping time of 20 minutes while stirring at the stirring speed shown in Table 8. The amount of aqueous dispersion added per 100 parts by mass of liquid aqueous solution was 53.1 parts by mass. The coagulation time (time from the start of dropping to the completion of dropping) is shown in Table 8. The coagulation temperature T was measured using a K-type thermocouple. ３ Table 8 shows the volume median particle size D50B of the aggregates in the liquid aqueous solution measured by the method described above.

[0221] <Measurement and Evaluation> The solid composition A4, consisting of aggregates of the obtained fluorine-containing elastomer A1, was separated from the liquid aqueous solution A4 by filtration while maintaining the aggregation temperature at ±5.0°C. The volume-average particle size D50A, specific surface area, bulk density, total content of (S1) and (S2), compound (A) content, compound (B) content, metal content, 5% mass thermal weight loss temperature, and storage modulus of the obtained solid composition A4 were measured by the method described above. The results are shown in Table 8. The crosslinking rate of the obtained solid composition A4 was measured by the method described above. The results are shown in Table 8.

[0222] [Example A5] <Aqueous dispersion preparation step> The aqueous dispersion A-A1 obtained in Example A1 was used.

[0223] <Agglomeration Process> A liquid aqueous solution A5 containing 40% by mass of nitric acid was prepared. The temperature of liquid aqueous solution A5 was T １ The temperature is -12.0°C, and the temperature of aqueous dispersion A-A1 is T ２Each solution was cooled to +7.0°C, and aqueous dispersion A-A1 was added dropwise to liquid aqueous solution A5 over a period of 10 minutes while stirring at the stirring speed shown in Table 8. The amount of aqueous dispersion added per 100 parts by mass of liquid aqueous solution was 53.1 parts by mass. The coagulation time (time from the start of dropping to the completion of dropping) is shown in Table 8. The coagulation temperature T was measured using a K-type thermocouple. ３ Table 8 shows the volume median particle size D50B of the aggregates in the liquid aqueous solution measured by the method described above.

[0224] <Measurement and Evaluation> The solid composition A5, consisting of aggregates of the obtained fluorine-containing elastomer A1, was separated from the liquid aqueous solution A5 by filtration while maintaining the aggregation temperature at ±5.0°C. The volume-average particle size D50A, specific surface area, bulk density, total content of (S1) and (S2), compound (A) content, compound (B) content, metal content, 5% mass thermal weight loss temperature, and storage modulus of the obtained solid composition A5 were measured by the method described above. The results are shown in Table 8. The crosslinking rate of the obtained solid composition A5 was measured by the method described above. The results are shown in Table 8.

[0225] [Example A6] <Aqueous dispersion preparation step> The aqueous dispersion A-A1 obtained in Example A1 was used.

[0226] <Agglomeration Process> A liquid aqueous solution A6 containing 40% by mass of nitric acid was prepared. The temperature of liquid aqueous solution A6 was T １ The temperature is -15.7°C, and the temperature of aqueous dispersion A-A1 is T ２ Each solution was cooled to +7.0°C, and aqueous dispersion A-A1 was added dropwise to liquid aqueous solution A6 over a period of 50 minutes while stirring at the stirring speed shown in Table 8. The amount of aqueous dispersion added per 100 parts by mass of liquid aqueous solution was 53.1 parts by mass. The coagulation time (time from the start of dropping to the completion of dropping) is shown in Table 8. The coagulation temperature T was measured using a K-type thermocouple. ３ Table 8 shows the volume median particle size D50B of the aggregates in the liquid aqueous solution measured by the method described above.

[0227] <Measurement and Evaluation> The solid composition A6, consisting of aggregates of the obtained fluorine-containing elastomer A1, was separated from the liquid aqueous solution A6 by filtration while maintaining the aggregation temperature at ±5.0°C. The volume-average particle size D50A, specific surface area, bulk density, total content of (S1) and (S2), compound (A) content, compound (B) content, metal content, 5% mass thermal weight loss temperature, and storage modulus of the obtained solid composition A6 were measured by the method described above. The results are shown in Table 8. The crosslinking rate of the obtained solid composition A6 was measured by the method described above. The results are shown in Table 8.

[0228] [Example A7] <Aqueous dispersion preparation step> The aqueous dispersion A-A1 obtained in Example A1 was used.

[0229] <Agglomeration Process> A liquid aqueous solution A7 containing 20% ​​by mass of nitric acid was prepared. The temperature of liquid aqueous solution A7 was T １ The temperature is +23.5°C, and the temperature of aqueous dispersion A-A1 is T ２ The temperature was adjusted to +20.7°C, and aqueous dispersion A-A1 was added dropwise to liquid aqueous solution A7 over a dropping time of 60 minutes while stirring at the stirring speed shown in Table 8. The amount of aqueous dispersion added per 100 parts by mass of liquid aqueous solution was 53.1 parts by mass. The coagulation time (time from the start of dropping to the completion of dropping) is shown in Table 8. The coagulation temperature T was measured using a K-type thermocouple. ３ Table 8 shows the volume median particle size D50B of the aggregates in the liquid aqueous solution measured by the method described above.

[0230] <Measurement and Evaluation> The solid composition A7, consisting of aggregates of the obtained fluorine-containing elastomer A1, was separated from the liquid aqueous solution A7 by filtration while maintaining the aggregation temperature at ±5.0°C. The volume-average particle size D50A, the sum of the (S1) and (S2) content, the compound (A) content, the compound (B) content, the metal content, the 5% mass thermal weight loss temperature, and the storage modulus of the obtained solid composition A7 were measured by the method described above. The results are shown in Table 8. The crosslinking rate of the obtained solid composition A7 was measured by the method described above. The results are shown in Table 8.

[0231] [Example A8] <Preparation Process of Aqueous Dispersion> (First Polymerization Process) Into a 2.2 L stainless steel pressure reactor equipped with anchor blades, ultrapure water (1130 g), 30% by mass ammonia aqueous solution (30 mg), PMVE (72 g), and TFE (14 g) were charged, and the temperature was raised to 90°C while stirring at 600 rpm. Next, an ammonium persulfate aqueous solution (5.0% by mass, 30 cc) was added to initiate the polymerization. Since the pressure in the reactor decreased upon the start of the polymerization, TFE was added to maintain the pressure constant. When 4 g of TFE was injected, the reactor was cooled to 10°C to terminate the polymerization reaction. After collecting the gas remaining in the reactor, the liquid was withdrawn. This liquid was used as the raw material liquid A-A2 (first aqueous dispersion). After the raw material liquid A-A2 was frozen and aggregated, it was filtered, and the resulting first fluorine-containing polymer A2 was analyzed by NMR. As a result, the PMVE unit / TFE unit = 30 / 70 (molar ratio).

[0232] (Purification Process) HPR4002Cl (manufactured by DuPont, an anion exchange resin, 200 g) was added to the above raw material liquid A-A2. 150 minutes after starting the stirring, the raw material liquid and the anion exchange resin were separated by filtration. Next, AmberLite (registered trademark) HPR650H (manufactured by DuPont, a cation exchange resin, 50 g) was added to the filtrate. 60 minutes after starting the stirring, the raw material liquid and the cation exchange resin were separated by filtration to obtain the raw material liquid B-A2. In the raw material liquid B-A2, the particles of the first fluorine-containing polymer A2 were dispersed in the aqueous medium, and the content of the first fluorine-containing polymer A2 was 0.6% by mass based on the total mass of the raw material liquid B-A2.

[0233] (Concentration adjustment step, second polymerization step) A stainless steel pressure reactor with an internal volume of 2.2 L equipped with anchor blades was charged with raw material liquid B-A2 (1000 g) and ultrapure water (175 g) to obtain aqueous dispersion B-A2. The content of the first fluorine-containing polymer A2 was 0.4% by mass relative to the total mass of aqueous dispersion B-A2. Perfluoro-1,4-diiodobutane (C4DI, 2.0 g), PMVE (72 g), and TFE (14 g) were charged into the aqueous dispersion B-A2, and the temperature was raised to 80°C while stirring at 600 rpm. TFE and PMVE were injected under pressure until the reactor pressure reached 1.2 MPa [gauge], and an aqueous solution of ammonium persulfate (APS aqueous solution, 1.0% by mass, 20 mL) was added to start polymerization. As polymerization began, the pressure inside the reactor decreased, so TFE was added to maintain a constant pressure. After injecting 160g of TFE and 133g of PMVE under pressure, the reactor was cooled to 10°C to terminate the polymerization reaction. After recovering the gas remaining in the reactor after the polymerization reaction was complete, the liquid was removed from the reactor. This liquid was designated as the second aqueous dispersion A2.

[0234] The second aqueous dispersion A2 was a dispersion in which particles (average particle size 92.7 nm) containing the first fluorine-containing polymer A2 and the second fluorine-containing polymer A2, were dispersed in an aqueous medium, and the solid content concentration was 20.5% by mass.

[0235] <Agglomeration Process> A liquid aqueous solution A8 containing 20% ​​by mass of nitric acid was prepared. The temperature of liquid aqueous solution A8 was T １ is -20.0°C, the temperature T of the second aqueous dispersion A2 ２ Each solution was cooled to +15.0°C, and while stirring liquid aqueous solution A8 at the stirring speed shown in Table 9, the second aqueous dispersion A2 was added dropwise to liquid aqueous solution A8 over a dropping time of 15 minutes. The amount of aqueous dispersion added per 100 parts by mass of liquid aqueous solution was 40 parts by mass. The coagulation time (time from the start of dropping to the completion of dropping) is shown in Table 9. The coagulation temperature T was measured using a K-type thermocouple. ３ Table 9 shows the volume median particle size D50B of the aggregates in the liquid aqueous solution measured by the method described above.

[0236] <Measurement and Evaluation> Solid composition A8, consisting of aggregates of the obtained fluorine-containing elastomer A2, was separated from liquid aqueous solution A8 by filtration while maintaining the aggregation temperature at ±5.0°C. NMR analysis of the fluorine-containing elastomer A2 contained in the obtained solid composition A8 revealed a PMVE / TFE ratio of 35 / 65 (molar ratio). Furthermore, fluorine-containing elastomer A2 did not have a melting point. The Tg of fluorine-containing elastomer A2 is shown in Table 9. The volume-average particle size D50A, specific surface area, bulk density, total content of (S1) and (S2), compound (A) content, compound (B) content, metal content, 5% mass thermal weight loss temperature, and storage modulus of the obtained solid composition A8 were measured using the method described above. The results are shown in Table 9. The crosslinking rate of the obtained solid composition A8 was measured using the method described above. The results are shown in Table 9.

[0237] [Example A9] <Aqueous dispersion preparation step> The second aqueous dispersion A2 obtained in Example A8 was used.

[0238] <Agglomeration Process> A liquid aqueous solution A9 containing 20% ​​by mass of nitric acid was prepared. The temperature of liquid aqueous solution A9 was T １ is +20.0°C, the temperature T of the second aqueous dispersion A2 ２ Each solution was cooled to +22.0°C, and the second aqueous dispersion A2 was added dropwise to the liquid aqueous solution A9 over a period of 15 minutes while stirring the liquid aqueous solution A9 at the stirring speed shown in Table 9. The amount of aqueous dispersion added per 100 parts by mass of liquid aqueous solution was 53 parts by mass. The coagulation time (time from the start of dropping to the completion of dropping) is shown in Table 9. The coagulation temperature T was measured using a K-type thermocouple. ３ Table 9 shows the volume median particle size D50B of the aggregates in the liquid aqueous solution measured by the method described above.

[0239] <Measurement and Evaluation> The solid composition A9, consisting of aggregates of the obtained fluorine-containing elastomer A2, was separated from the liquid aqueous solution A9 by filtration while maintaining the aggregation temperature at ±5.0°C. The volume-average particle size D50A, specific surface area, bulk density, total content of (S1) and (S2), compound (A) content, compound (B) content, metal content, 5% mass thermal weight loss temperature, and storage modulus of the obtained solid composition A9 were measured by the method described above. The results are shown in Table 9. The crosslinking rate of the obtained solid composition A9 was measured by the method described above. The results are shown in Table 9.

[0240] [Example B1] <Aqueous dispersion preparation process> After degassing a 2.2 L stainless steel pressure reactor equipped with anchor blades, ultrapure water (1053 g) and emulsifier C ２ F ５ OCF ２ CF ２ OCF ２ COONH ４ 30% by mass aqueous solution of (EEA) (129 g), disodium hydrogen phosphate dodecahydrate (0.113 g), CF ２ = CFOCF ２ CF (CF ３ ) OCF ２ CF ２ CN(8CNVE) (1.1g) was added, and the gas phase was purged with nitrogen. While stirring at a speed of 600 rpm using an anchor blade, PMVE (72g) and TFE (14g) were injected into the container under pressure, and the internal temperature was raised to 80°C. Next, an aqueous APS solution (3.0% by mass, 18 ml) was added, and polymerization was started. As polymerization began, the pressure inside the reactor decreased, so TFE and PMVE were added to maintain a constant pressure of 0.918 MPa [gauge]. After injecting 160g of TFE and 108g of PMVE, the reactor was cooled to 10°C to stop the polymerization reaction, the remaining gas in the reactor was recovered, and the liquid was withdrawn to obtain aqueous dispersion A-D2. The average particle size of the fluorine-containing elastomer D2 particles in aqueous dispersion A-D2 was 27.9 nm, and the solid content concentration of aqueous dispersion A-D2 was 20.1% by mass.

[0241] <Agglomeration Process> A liquid aqueous solution B1 containing 20% ​​by mass of nitric acid was prepared. The temperature of liquid aqueous solution B1 was T １ The temperature is -12.0°C, and the temperature of aqueous dispersion A-D2 is T ２ Each solution was cooled to +3.0°C, and aqueous dispersions A-D2 were added dropwise to aqueous solution B1 over a dropping time of 20 minutes while stirring at the stirring speed shown in Table 9. The amount of aqueous dispersion added per 100 parts by mass of aqueous solution was 53 parts by mass. The coagulation time (time from the start of dropping to the completion of dropping) is shown in Table 9. The coagulation temperature T was measured using a K-type thermocouple. ３ Table 9 shows the volume median particle size D50B of the aggregates in the liquid aqueous solution measured by the method described above.

[0242] <Measurement and Evaluation> Solid composition B1, consisting of aggregates of the obtained fluorine-containing elastomer D2, was separated from liquid aqueous solution B1 by filtration while maintaining the aggregation temperature at ±5.0°C. NMR analysis of the fluorine-containing elastomer D2 contained in the obtained solid composition B1 revealed a composition of PMVE / TFE / 8CNVE = 29.6 / 69.7 / 0.7 (molar ratio). Furthermore, the fluorine-containing elastomer D2 did not have a melting point. The Tg of the fluorine-containing elastomer D2 is shown in Table 9. The volume-average particle size D50A, specific surface area, bulk density, total (S1) content and (S2) content, compound (A) content, compound (B) content, metal content, 5% mass thermal weight loss temperature, and storage modulus of the obtained solid composition B1 were measured using the method described above. The results are shown in Table 9. The crosslinking rate of the obtained solid composition B1 was measured using the method described above. The results are shown in Table 9.

[0243] [Example B2] <Aqueous dispersion preparation step> The aqueous dispersion A-D2 obtained in Example B1 was used.

[0244] <Agglomeration Process> A liquid aqueous solution B2 was prepared containing 10% by mass of methanol and 5% by mass of potassium aluminum sulfate (potassium alum). The temperature of liquid aqueous solution B2 was T １ The temperature of aqueous dispersion A-D2 is +60.0°C. ２Each solution was cooled to +25.0°C, and aqueous dispersions A-D2 were added dropwise to aqueous solution B2 over a dropping time of 10 minutes while stirring at the stirring speed shown in Table 9. The amount of aqueous dispersion added per 100 parts by mass of aqueous solution was 53 parts by mass. The coagulation time (time from the start of dropping to the completion of dropping) is shown in Table 9. The coagulation temperature T was measured using a K-type thermocouple. ３ Table 9 shows the volume median particle size D50B of the aggregates in the liquid aqueous solution measured by the method described above.

[0245] <Measurement and Evaluation> The solid composition B2, consisting of aggregates of the obtained fluorine-containing elastomer D2, was separated from the liquid aqueous solution B2 by filtration while maintaining the aggregation temperature at ±5.0°C. The volume-average particle size D50A, specific surface area, bulk density, total content of (S1) and (S2), compound (A) content, compound (B) content, metal content, 5% mass thermal weight loss temperature, and storage modulus of the obtained solid composition B2 were measured by the method described above. The results are shown in Table 9. The crosslinking rate of the obtained solid composition B2 was measured by the method described above. The results are shown in Table 9.

[0246]

[0247]

[0248] As shown in Tables 8-9, in Examples A1-A6 and A8, solid compositions with faster crosslinking rates were obtained compared to Examples A7 and A9. Similarly, in Example B1, a solid composition with a faster crosslinking rate was obtained compared to Example B2.

[0249] The disclosure of Japanese Patent Application No. 2025-009397, filed on 22 January 2025, is incorporated herein by reference in its entirety. Furthermore, all documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually indicated as being incorporated by reference.

Claims

1. A method for producing a solid composition containing a fluorine-containing elastomer comprising a constituent unit based on at least one selected from the group consisting of tetrafluoroethylene and vinylidene fluoride, wherein the elastomer has a glass transition temperature of +10.0°C or lower, comprising: an aqueous dispersion preparation step of preparing an aqueous dispersion containing an aqueous medium and particles of the fluorine-containing elastomer dispersed in the aqueous medium; and an aggregation step of bringing the aqueous dispersion into contact with a liquid aqueous solution containing water and having a temperature of Tg or lower, when the glass transition temperature of the fluorine-containing elastomer is Tg, and agglomerating the particles at an aggregation temperature of Tg + 5.0°C or lower to obtain a solid composition containing aggregates of the particles.

2. The method for producing a solid composition according to claim 1, wherein the volume average particle size D50A of the aggregates contained in the solid composition separated from the liquid aqueous solution at a coagulation temperature of ±5.0°C is 500 μm or less.

3. The method for producing a solid composition according to claim 1 or 2, wherein the volume median particle size D50B of the aggregates in the liquid aqueous solution is 500 μm or less.

4. The method for producing a solid composition according to claim 1 or 2, wherein the liquid aqueous solution contains an alcohol having 1 to 4 carbon atoms and a boiling point of less than 100°C.

5. The method for producing the solid composition according to claim 1 or 2, wherein the liquid aqueous solution contains an inorganic salt.

6. A method for producing a solid composition according to claim 1 or 2, wherein the fluorine-containing elastomer comprises a structural unit based on tetrafluoroethylene and a structural unit based on perfluoro(alkyl vinyl ether).

7. The method for producing a solid composition according to claim 1 or 2, wherein the fluorine-containing elastomer has at least one selected from the group consisting of a chlorine atom, a bromine atom, an iodine atom, and a cyano group.

8. The method for producing a solid composition according to claim 1 or 2, wherein the aqueous dispersion preparation step includes a polymerization step of polymerizing a monomer containing at least one selected from the group consisting of tetrafluoroethylene and vinylidene fluoride in the aqueous medium.

9. A fluorine-containing elastomer comprising a structural unit based on at least one selected from the group consisting of tetrafluoroethylene and vinylidene fluoride and having a glass transition temperature of +10.0 °C or lower, and at least one selected from the group consisting of the compound (S1) represented by the formula (S1) and the compound (S2) represented by the formula (S2). A solid composition, wherein the total content of the compound (S1) and the compound (S2) with respect to the entire solid composition is less than 250 mass ppb. H(CF ２ ) ｐ１ COOM １ (S!): H(CF ２ ) ｐ２ SO ３ M ２ (S2): In the formulas (S1) and (S2), M １ and M ２ are each independently a hydrogen atom, Na, K, or NH ４ ; p1 is an integer from 3 to 13; and p2 is an integer from 4 to 10.

10. A solid composition containing a fluorine-containing elastomer having a glass transition temperature of +10.0°C or lower, comprising a structural unit based on at least one selected from the group consisting of tetrafluoroethylene and vinylidene fluoride, wherein the solid composition does not contain the compound (S1) represented by formula (S1), the compound (S2) represented by formula (S2), the compound (S3) represented by formula (S3), the compound (S4) represented by formula (S4), the compound (S5) represented by formula (S5), the compound (S6) represented by formula (S6), the compound (S7) represented by formula (S7), the compound (S8) represented by formula (S8), the compound (S9) represented by formula (S9), and the compound (S10) represented by formula (S10), or contains at least one selected from the group consisting of the compounds (S1) to (S10), with the total content of the compounds (S1) to (S10) being less than 250 ppb by mass relative to the solid composition. ２ ) ｐ１ COOM １ (S1) H(CF ２ ) ｐ２ SO ３ M ２ (S2) F(CF) ２ ) ｐ３ COOM ３ (S3) F(CF) ２ ) ｐ４ SO ３ M ４ (S4) X ５１ (CF ２ ) ｐ５ (OCF ２ CF ２ CF ２ ) ｑ５ OCF(X ５２ ) CF ２ COOM ５ (S5) X ６１ (CF ２ ) ｐ６ (OCF(X ６２ ) CF(X ６３ )) ｑ６ OCF(X ６４ ) COOM ６ (S6) X ７１ (CF ２ ) ｐ７ CF(X ７２ ) (OCF(X ７３ ) CF(X ７４ )) ｑ７ OCF(X ７５ ) COOM ７ (S7) X １０１ CF ２ (OCF ２ CF ２ ) ｑ１０ (OCF ２ ) ｒ１０ X １０２ (S10) In formulas (S1) to (S10), M １ ~M ９ Each is independently a hydrogen atom, Na, K, or NH ４ X ５１ , X ６１ , X ７１ , X ８１ , X ８２ , X ９１ , and X ９２ Each of these is independently a hydrogen atom, a fluorine atom, or a chlorine atom, and X １０１ and X １０２ Each of these is independently a hydrogen atom, a fluorine atom, a COOH group, or a chlorine atom, and X １０１ and X １０２ At least one of them is COOH, X ５２ , X ６２ ~X ６４ , and X ７２ ~X ７５ Each of these is independently a hydrogen atom, a fluorine atom, or a perfluoroalkyl group having 1 to 3 carbon atoms, and Rf ８ ~Rf ９ Each is independently a fluorine-containing alkylene group having 1 to 20 carbon atoms, p1 and p3 are independently integers from 3 to 13, p2 and p4 are independently integers from 4 to 10, p5 to p7 are independently integers from 1 to 10, q5 to q7 are independently integers from 0 to 3, q8 to q9 are independently integers from 1 to 20, n8 to n9 are independently integers from 1 to 30, and q8 and n8 are the CF of compound (S8). ２ A combination of integers such that the number of elements is 30 or less, where q9 and n9 are the CFs of the compound (S9). ２ The integer combination is such that the number of groups is 30 or less, q10 and r10 are each independent integers of 0 or greater, and q10 and r10 are integer combinations such that the number-average molecular weight of the compound (S10) is between 300 and 1000.

11. A solid composition containing a fluorine-containing elastomer comprising a structural unit selected from the group consisting of tetrafluoroethylene and vinylidene fluoride, wherein the glass transition temperature is +10.0°C or lower, and comprising 1 or more CF ２ It has a group and one or more ionic functional groups, wherein the ionic functional groups are COOM, SO ３ M, PO ４ M, or SO ４ M is a hydrogen atom, Na, K, or NH ４ The CF per ionic functional group ２ When compound (B) is defined as a compound having 30 or fewer groups, lacking carbon-carbon double bonds and carbon-carbon triple bonds, and having a number-average molecular weight of 3000 or less, the solid composition either does not contain compound (B) or contains compound (B) such that the total content of compound (B) is less than 250 ppb by mass relative to the solid composition.

12. The solid composition according to any one of claims 9 to 11, wherein the solid composition contains aggregates of particles containing the fluorine-containing elastomer, and the volume average particle size D50A of the aggregates is 500 μm or less.

13. The solid composition according to any one of claims 9 to 11, wherein the fluorine-containing elastomer comprises a structural unit based on tetrafluoroethylene and a structural unit based on perfluoro(alkyl vinyl ether).

14. The solid composition according to any one of claims 9 to 11, wherein the fluorine-containing elastomer has at least one selected from the group consisting of a chlorine atom, a bromine atom, an iodine atom, and a cyano group.

15. The solid composition according to any one of claims 9 to 11, wherein the storage modulus G' of the solid composition is 10 to 1000 kPa.

16. The solid composition according to any one of claims 9 to 11, wherein the 5% by mass thermal weight loss temperature of the solid composition is 350°C or higher.

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