Fluorine-containing copolymer composition and method for producing the same, and crosslinked product composition and method for producing the same

Abstract

To provide a fluorine-containing copolymer composition and its production method, by which a crosslinked product having abrasion resistance and reduced tendency to damage a mating material can be yielded, and to provide a crosslinked product composition including a crosslinked product formed by crosslinking a fluorine-containing copolymer in the fluorine-containing copolymer composition, and its production method.SOLUTION: A fluorine-containing copolymer composition comprises a fluorine-containing copolymer and an inorganic filler, the fluorine-containing copolymer including structural unit (A) derived from tetrafluoroethylene, structural unit (B) derived from perfluoroalkyl vinyl ether, and structural unit (C) derived from a fluorine-containing compound represented by the following formula (1). [In formula (1), R1-R3 are fluorine atoms; R4 is a hydrogen atom, a fluorine atom, or the like; Z is an oxygen atom; X is a single bond or a difluoromethylene group; Y1-Y4 are fluorine atoms or trifluoromethyl groups; and Q is a perfluoroalkylene group.]SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a fluorine-containing copolymer composition and a method for producing the same, and a crosslinked composition and a method for producing the same, and in particular to a fluorine-containing copolymer composition which gives a crosslinked product which has abrasion resistance and is unlikely to damage mating materials, a method for producing the same, and a crosslinked composition which contains a crosslinked product obtained by crosslinking a fluorine-containing copolymer in the fluorine-containing copolymer composition, and a method for producing the same. [Background technology]

[0002] FFKM is a fluorine-containing copolymer containing tetrafluoroethylene (TFE) and perfluoroalkyl vinyl ethers such as perfluoromethyl vinyl ether (PMVE) as monomer structural units, and is also known as a perfluoroelastomer. Rubbers (crosslinked products) obtained by crosslinking FFKM have excellent heat resistance and chemical resistance, and are therefore used in a wide range of applications, such as as sealing materials and cushioning materials for O-rings, packings, oil seals, and gaskets, in semiconductor manufacturing, vehicles, aircraft, general machinery, construction, and chemical plants.

[0003] As a crosslinking method, for example, a method of crosslinking at the terminal iodine atoms of the monomer using a peroxide such as 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane as a crosslinking agent is known. Furthermore, from the viewpoint of increasing the rate of the crosslinking reaction, it has also been proposed to use a bismaleimide compound as a crosslinking aid (see Patent Document 1).

[0004] In addition, a method is also known in which a fluorine-containing compound having a nitrile group is introduced into FFKM as a monomer constituent unit, and a crosslinked structure containing a triazine ring is formed by trimerization of the nitrile group using tetraphenyltin as a catalyst (see Patent Document 2).

[0005] Furthermore, from the viewpoint of reducing the compression set of the crosslinked product at high temperatures of around 300°C, it has also been proposed to introduce a fluorine-containing compound having a nitrile group into FFKM as a monomer constituent unit and to use a bisaminophenol compound such as 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane as a crosslinking agent to form a crosslinked structure containing an oxazole ring (see Patent Documents 3 and 4). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2021 / 166664 [Patent Document 2] Special Publication No. 63-5409 [Patent Document 3] Special Publication No. 2-59177 [Patent Document 4] International Publication No. 2021 / 210503 Summary of the Invention [Problem to be solved by the invention]

[0007] As the use of cross-linked rubber expands in various industries (for example, as a sealant for dynamic parts such as vacuum pumps for dry etching of semiconductors), it is required that the rubber be abrasion resistant and less likely to damage mating materials. The same properties are also desired for the cross-linked rubber obtained by cross-linking FFKM.

[0008] However, even the rubbers (crosslinked products) described in Patent Documents 1 to 4 do not necessarily have abrasion resistance and are not likely to damage mating materials.

[0009] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a fluorocopolymer composition which gives a crosslinked product which has abrasion resistance and is unlikely to damage mating materials, a method for producing the same, and a crosslinked product composition which contains a crosslinked product obtained by crosslinking a fluorocopolymer in the fluorocopolymer composition, and a method for producing the same. [Means for solving the problem]

[0010] The present invention is based on the finding that a crosslinked product obtained from a fluorocopolymer composition comprising a predetermined fluorocopolymer and an inorganic filler has abrasion resistance and is less likely to damage mating materials.

[0011] [1] A fluorine-containing copolymer composition comprising a fluorine-containing copolymer and an inorganic filler, The fluorine-containing copolymer composition, wherein the fluorine-containing copolymer comprises a structural unit (A) derived from tetrafluoroethylene, a structural unit (B) derived from a perfluoroalkyl vinyl ether, and a structural unit (C) derived from a fluorine-containing compound represented by the following formula (1): [ka] [In formula (1), R 1 ~R 3 is a fluorine atom. R 4 is a monovalent organic group having 1 to 8 carbon atoms that does not contain a hydrogen atom, a fluorine atom, or a carbonyl group. Z is an oxygen atom. X is a single bond or a difluoromethylene group. Y 1 ~Y 4 are each independently a fluorine atom or a trifluoromethyl group. Q is a perfluoroalkylene group having 1 to 8 carbon atoms which may contain an etheric oxygen atom.] [2] The fluorine-containing copolymer composition according to the above [1], wherein, in a total of 100% by mass of the structural units (A) to (C), the structural unit (A) accounts for 10.0 to 99.9% by mass, the structural unit (B) accounts for 0.0 to 70.0% by mass, and the structural unit (C) accounts for 0.1 to 20.0% by mass. [3] The fluorine-containing copolymer composition according to the above [1] or [2], wherein the content of the inorganic filler is 1 to 60 parts by mass per 100 parts by mass of the fluorine-containing copolymer. [4] The fluorine-containing copolymer composition according to any one of the above [1] to [3], wherein the inorganic filler has an average particle size of 12,000 nm or less. [5] The fluorine-containing copolymer composition according to any one of the above [1] to [4], wherein the inorganic filler is at least one selected from the group consisting of carbon black, silicon dioxide, aluminum oxide, magnesium oxide, silicon carbide, silicon nitride, aluminum nitride, crystalline zeolite, and nanodiamond. [6] Further containing a crosslinking aid, The fluorine-containing copolymer composition according to any one of the above [1] to [5], wherein the crosslinking aid is at least one selected from the group consisting of water and triphenylsulfonium nonafluoro-1-butanesulfonate. [7] A crosslinked composition comprising a crosslinked product obtained by crosslinking the fluorocopolymer in the fluorocopolymer composition according to any one of [1] to [6] above. [8] The crosslinked composition according to [7] above, wherein the crosslinked structure of the crosslinked product contains an indole ring. [9] A method for producing the fluorine-containing copolymer composition according to any one of the above [1] to [6], comprising the steps of: A method for producing a fluorine-containing copolymer composition, which comprises kneading the fluorine-containing copolymer and the inorganic filler.

[10] A method for producing the crosslinked composition according to [7] or [8] above, The fluorine-containing copolymer composition, First heating at 80-200℃ for 0.1-6 hours, After the primary heating, the composition is secondarily heated at 200 to 300°C for 1 to 24 hours. [Effects of the Invention]

[0012] According to the present invention, there can be provided a fluorocopolymer composition which gives a crosslinked product which has abrasion resistance and is unlikely to damage a mating material, a method for producing the same, and a crosslinked product composition which contains a crosslinked product obtained by crosslinking the fluorocopolymer in the fluorocopolymer composition, and a method for producing the same. DETAILED DESCRIPTION OF THE INVENTION

[0013] The definitions and meanings of terms and expressions used in this specification are shown below. In this specification, "room temperature" means 20 to 25°C. In this specification, the "content of the monomer constitutional unit in the fluorine-containing copolymer" refers to the content of the monomer constitutional unit in the fluorine-containing copolymer measured by a nuclear magnetic resonance (NMR) measurement device. 1 H-NMR and 19 This is a value calculated from the results of F-NMR measurement, specifically by the method described in the Examples. In this specification, "short-term heat resistance" means that the mechanical properties, particularly the storage modulus, show almost no change when heated from room temperature to approximately 300°C in a test based on the "tensile vibration non-resonance method" specified in JIS K 7244-4:1999. In this specification, "long-term heat resistance" means that the mechanical properties are maintained for 72 hours or more at high temperatures of about 300°C. In this specification, the preferred definitions can be adopted arbitrarily, and it can be said that a combination of preferred definitions is more preferred. In this specification, the expression "XX to YY" means "XX or more and YY or less." In this specification, for preferred numerical ranges (e.g., ranges of content, etc.), the lower and upper limits described in stages can be independently combined. For example, the description "preferably 10 to 90, more preferably 30 to 60" can be combined with the "preferable lower limit (10)" and the "more preferable upper limit (60)" to form "10 to 60." Furthermore, in the numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with a value shown in the examples.

[0014] [Fluorine-containing copolymer composition] The fluorine-containing copolymer composition of an embodiment of the present invention (hereinafter sometimes simply referred to as "the present embodiment") is not particularly limited as long as it contains a predetermined fluorine-containing copolymer and an inorganic filler, and may or may not contain a compound (D) described below, other additives, etc., as necessary.

[0015] The contents of the fluorine-containing copolymer and inorganic filler are not particularly limited, but from the viewpoint of producing a fluorine-containing copolymer composition which gives a crosslinked product which has abrasion resistance and is less likely to damage the mating material, the contents are preferably 50% by mass or more, more preferably 65% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more, based on 100% by mass of the fluorine-containing copolymer composition.

[0016] <Fluorine-containing copolymer> The fluorine-containing copolymer contained in the fluorine-containing copolymer composition of the present embodiment contains a structural unit (A) derived from the monomer tetrafluoroethylene (TFE), a structural unit (B) derived from the monomer perfluoroalkyl vinyl ether (PAVE), and a structural unit (C) derived from the monomer fluorine-containing compound represented by the following formula (1): By introducing the structural unit (C) into FFKM, a fluorine-containing copolymer composition can be obtained which will give a crosslinked product having excellent short-term heat resistance and long-term heat resistance. [ka] [In formula (1), R 1 ~R 3 is a fluorine atom. R 4 is a monovalent organic group having 1 to 8 carbon atoms that does not contain a hydrogen atom, a fluorine atom, or a carbonyl group. Z is an oxygen atom. X is a single bond or a difluoromethylene group. Y 1 ~Y 4 are each independently a fluorine atom or a trifluoromethyl group. Q is a perfluoroalkylene group having 1 to 8 carbon atoms which may contain an etheric oxygen atom.]

[0017] From the viewpoint of good heat resistance and rubber properties of the crosslinked product, the fluorine-containing copolymer of the present embodiment preferably contains 10.0 to 99.9 mass% of the structural units (A), 0.0 to 70.0 mass% of the structural units (B), and 0.1 to 20.0 mass% of the structural units (C) in a total of 100 mass% of the structural units (A) to (C). The content of the structural unit (A) is not particularly limited as long as it is 10.0 to 99.9 mass% of the total 100 mass% of the structural units (A) to (C), but is preferably 29.9 to 80.0 mass%, more preferably 38.8 to 75.0 mass%, and particularly preferably 45.5 to 70.0 mass%. The content of the structural unit (B) is not particularly limited as long as it is 0.0 to 70.0 mass% relative to 100 mass% of the total of the structural units (A) to (C), but is preferably 19.9 to 70.0 mass%, more preferably 24.8 to 60.0 mass%, and particularly preferably 29.5 to 50.0 mass%. The content of the structural unit (C) is not particularly limited as long as it is 0.1 to 20.0 mass% relative to 100 mass% of the total of the structural units (A) to (C), but is preferably 0.1 to 18.0 mass%, more preferably 0.2 to 15.0 mass%, and particularly preferably 0.5 to 10.0 mass%.

[0018] (Structural unit (A) derived from TFE) The monomer that forms the structural unit (A) is TFE. The structure of TFE is represented by CF2=CF2.

[0019] (B) is a structural unit derived from PAVE. The monomer that forms the structural unit (B) is PAVE. From the viewpoint of good polymerization reactivity and rubber properties, the number of carbon atoms in the perfluoroalkyl group of PAVE is preferably 1 to 10, more preferably 1 to 8, even more preferably 1 to 6, still more preferably 1 to 5, and particularly preferably 1 to 3. The perfluoroalkyl group may be linear or branched.

[0020] Specific examples of PAVE include perfluoromethyl vinyl ether (PMVE), perfluoroethyl vinyl ether (PEVE), and perfluoro n-propyl vinyl ether (PPVE). PAVE may be used alone or in combination of two or more. Among these, from the viewpoint of polymerization reactivity, PMVE and PEVE are preferred, and PMVE is more preferred.

[0021] (Structural unit (C) derived from a fluorine-containing compound) The monomer that becomes the structural unit (C) is a fluorine-containing compound represented by the formula (1) described below. The fluorine-containing compound represented by formula (1) may be used alone or in combination of two or more types.

[0022] -Fluorine-containing compounds- The fluorine-containing compound is represented by the following formula (1). This compound is a fluorine-containing compound having a vinyl group or a fluorovinyl group as a polymerizable unsaturated bond and a carbonyl group in the main chain.The fluorine-containing compound having such a structure can be introduced into FFKM as a monomer structural unit to form a crosslinked product of a fluorine-containing copolymer having a crosslinked structure containing an indole ring.Such a crosslinked product has excellent short-term heat resistance and long-term heat resistance, and by using the fluorine-containing compound, a fluorine-containing copolymer suitable for obtaining the crosslinked product can be formed.

[0023] [ka] In formula (1), R 1 ~R 3 is a fluorine atom.

[0024] In formula (1), R 4 is a monovalent organic group having 1 to 8 carbon atoms and not containing a hydrogen atom, a fluorine atom, or a carbonyl group. From the viewpoint of ease of synthesis of the fluorine-containing compound, the number of carbon atoms in the organic group is preferably 1 to 7, more preferably 1 to 6, and particularly preferably 1 to 5. The organic group may be linear, branched, or cyclic, but is preferably linear or branched. The organic group may contain a heteroatom such as a nitrogen atom, an oxygen atom, or a sulfur atom. In formula (1), R 4 Although it depends on the crosslinking agent used, it is a hydrogen atom in consideration of being a crosslinking site of the fluorine-containing copolymer. That is, the fluorine-containing compound has R at the molecular end. 4 It is preferred that the alkyl group has an acetyl group containing the following:

[0025] In formula (1), Z is an oxygen atom.

[0026] In formula (1), X is a single bond or a difluoromethylene group, and is preferably a single bond from the viewpoint of ease of synthesis of the fluorine-containing compound.

[0027] In formula (1), Y 1 ~Y 4 are each independently a fluorine atom or a trifluoromethyl group, and from the viewpoint of polymerization reactivity and heat resistance, Y 1 and Y 3 is a fluorine atom, and from the viewpoint of ease of synthesis of fluorine-containing compounds, Y 1 ~Y 4 are all fluorine atoms.

[0028] In formula (1), Q is a perfluoroalkylene group having 1 to 8 carbon atoms which may contain an etheric oxygen atom. From the viewpoint of ease of synthesis of the fluorine-containing compound, the number of carbon atoms in the perfluoroalkylene group is preferably 1 to 7, more preferably 1 to 6. When an etheric oxygen atom is contained, the number of oxygen atoms is preferably 1 to 3, more preferably 1 or 2, and particularly preferably 1. In formula (1), Q may be linear or branched, and is preferably linear. In formula (1), Q is preferably a perfluoroalkylene group, particularly preferably a difluoromethylene group having one carbon atom, from the viewpoint of ease of synthesis of the fluorine-containing compound.

[0029] Specific examples of the compound represented by formula (1) include CF2=CFO(CF2)2(C=O)CH3, CF2=CFO(CF2)3(C=O)CH3 (hereinafter sometimes simply referred to as "CSM-1"), CF2=CFO(CF2)4(C=O)CH3, CF2=CFO(CF2)3O(CF2)2(C=O)CH3, CF2=CFOCF2C(CF3)FO(CF2)2(C=O)CH3, CF2=CFOCF2C(CF3)FO(CF2)3(C=O)CH3, etc. Of these, CSM-1 is preferred from the viewpoint of ease of synthesis, etc.

[0030] --Method of manufacturing fluorine-containing compounds-- The fluorine-containing compound can be obtained, for example, by reacting a perfluorovinyloxy polyether carboxylic acid or a derivative thereof with a reagent such as a Grignard reagent or an organolithium reagent to produce a ketone. Examples of the carboxylic acid derivative include esters and carboxylic acid halides. For example, when a Grignard reagent (organomagnesium halide: general formula RMgX) is used, a synthesis method can be applied in which the substituent (terminal group) bonded to the carbonyl group of the perfluorovinyloxy polyether carboxylic acid or a derivative thereof is replaced with the organic group R of the Grignard reagent. Specifically, the compound can be synthesized by the method described in the Examples, and is also commercially available.

[0031] The fluorine-containing copolymer may have structural units based on other monomers in addition to the monomers that constitute the structural units (A) to (C). From the viewpoint of heat resistance of the crosslinked product of the fluorocopolymer of this embodiment, the total of structural units based on other monomers is preferably 0 to 20 mass%, more preferably 0 to 15 mass%, and particularly preferably 0 to 10 mass%, relative to 100 mass% of the total of all monomer structural units of the fluorocopolymer of this embodiment. It is most preferable that no other monomers are contained. From the viewpoint of the heat resistance of the crosslinked product of the fluorocopolymer of this embodiment, the total of the monomers constituting the structural units (A) to (C) is preferably 80 to 100 mass%, more preferably 85 to 100 mass%, even more preferably 90 to 100 mass%, and particularly preferably 100 mass%, relative to 100 mass% of the total of all monomer structural units of the fluorocopolymer of this embodiment.

[0032] Examples of other monomers that serve as structural units other than the structural units (A) to (C) include vinylidene fluoride, chlorotrifluoroethylene, hexafluoropropylene, a fluorine-containing monomer having two polymerizable unsaturated groups (hereinafter sometimes simply referred to as "DVM"), 2,3,3,3-tetrafluoro-1-propene, hydrocarbon monomers, etc. The other monomers may be one type alone, or two or more types.

[0033] From the viewpoint of the heat resistance of the crosslinked product of the fluorocopolymer of this embodiment, the DVM is preferably a compound represented by the following formula (3): By using a DVM having two polymerizable unsaturated groups as a monomer, a fluorocopolymer having a branched chain can be obtained. (CR 21 R 22 =CR 23 )2R 24 (3)

[0034] In formula (3), R 21 , R 22 and R 23 are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 21 , R22 and R 23 may be the same or different, and are preferably the same. 21 , R 22 and R 23 is preferably a hydrogen atom or a fluorine atom from the viewpoint of polymerization reactivity, more preferably all hydrogen atoms or all fluorine atoms, and particularly preferably all fluorine atoms from the viewpoint of heat resistance.

[0035] R 24 is a perfluoroalkylene group having 1 to 10 carbon atoms which may contain an etheric oxygen atom. The number of carbon atoms in the perfluoroalkylene group is preferably 1 to 8, more preferably 1 to 6, and particularly preferably 1 to 4. When an etheric oxygen atom is contained, the number of oxygen atoms is preferably 1 to 3, more preferably 1 or 2, and particularly preferably 1. R 24 may be linear, branched or cyclic, is preferably linear or branched, and is more preferably linear.

[0036] Specific examples of DVM include CF2=CFO(CF2)2OCF=CF2, CF2=CFO(CF2)3OCF=CF2, CF2=CFO(CF2)4OCF=CF2, CF2=CFO(CF2)6OCF=CF2, CF2=CF O(CF2)8OCF=CF2, CF2=CFO(CF2)2OCF(CF3)CF2OCF=CF2, CF2=CFO(CF2)2O(CF(CF3)CF2O)2CF=CF2, CF2=CFOCF2O(CF2CF2O) Examples include CF2=CF2, CF2=CFO(CF2O)3(CF(CF3)CF2O)2CF=CF2, CF2=CFOCF2CF(CF3)O(CF2)2OCF(CF3)CF2OCF=CF2, CF2=CFOCF2CF2O(CF2O)2CF2CF2OCF=CF2, CF2=CFO(CF2)2CF=CF2, CH2=CH(CF2)2CH=CH2, CH2=CH(CF2)4CH=CH2, CH2=CH(CF2)6CH=CH2, etc. Among these, CF2=CFO(CF2)3OCF=CF2, CF2=CFO(CF2)4OCF=CF2 or CH2=CH(CF2)6CH=CH2 are preferred.

[0037] Examples of hydrocarbon monomers include olefins such as ethylene, propylene, isobutene, and 1-butene.

[0038] <<Fluorocopolymer manufacturing method>> The fluorine-containing copolymer of the present embodiment can be obtained by copolymerizing monomers that become structural units by emulsion polymerization, solution polymerization, suspension polymerization or the like in the presence of a radical polymerization initiator, for example, but the production method is not particularly limited. As the radical polymerization initiator, those known in the production of fluorine-containing copolymers can be used, and are appropriately selected depending on the polymerization method. For emulsion polymerization in an aqueous medium such as water, a water-soluble radical polymerization initiator is preferred, and examples thereof include persulfates such as ammonium persulfate, sodium persulfate, and potassium persulfate, disuccinic acid peroxide, azobisisobutylamidine dihydrochloride, tert-butyl hydroperoxide, and peroxydicarbonates. Of these, persulfates are preferred, and ammonium persulfate is more preferred. Redox polymerization initiators may also be used, which are combinations of persulfates or hydrogen peroxide with reducing agents such as sodium hydrogen sulfite and sodium thiosulfate, or the redox polymerization initiators may also be used in combination with a small amount of a metal or metal compound such as iron, ferrous salts, or silver sulfate. As a radical polymerization initiator for solution polymerization using a solvent such as 1H-perfluorohexane, for example, organic peroxides such as bis(pentafluoropropionyl) peroxide, pivaloyl tert-butyl peroxide, and diisopropyl peroxydicarbonate can be used. The radical polymerization initiator may be added all at once or gradually. The amount of the radical polymerization initiator used is preferably 0.0001 to 3 parts by mass, more preferably 0.001 to 2 parts by mass, and particularly preferably 0.01 to 1 part by mass, relative to 100 parts by mass of the total of all monomers to be polymerized.

[0039] A chain transfer agent may be added to the reaction system to adjust the moldability and mechanical properties of the fluorine-containing copolymer. Examples of chain transfer agents include saturated hydrocarbon compounds such as hexane and cyclohexane; alkyl group-containing aromatic compounds such as xylene and ethylbenzene; aliphatic alcohols such as methanol and isopropyl alcohol; carbonyl group-containing compounds such as acetic acid, methyl acetate, acetone, dimethyl carbonate, dimethylacetamide, N-methylsuccinimide and tetramethylurea; and nitrile compounds such as acetonitrile. Among these, ketones are preferred from the viewpoints of chain transfer performance and heat resistance of molded articles.

[0040] A pH buffer may be added to the reaction system, such as disodium hydrogen phosphate, sodium dihydrogen phosphate, sodium hydrogen carbonate, sodium carbonate, and hydrates thereof.

[0041] Examples of emulsifiers used in emulsion polymerization include hydrocarbon emulsifiers such as sodium lauryl sulfate and sodium dodecylbenzenesulfonate; ammonium perfluorooctanoate, sodium perfluorooctanoate, ammonium perfluorohexanoate, CF3(CF2)2O(CF(CF3)CF2O)2CF(CF3)COONH4, CF3(CF2)2OCF(CF3)CF2OCF(CF3)COONH4, CF3(CF2) 2OCF2CF2OCF2COONH4, CF3(CF2)2O(CF2CF2O)2CF2COONH4, CF3(CF2)3OCF2CF2OCF2COONH4, CF3(CF2)3O(CF2CF2O)2CF2C OONH4, CF3(CF2)2OCF2CF2OCF2COONa, CF3(CF2)2O(CF2CF2O)2CF2COONa, CF3(CF2)3OCF2CF2OCF2COONa, CF3(CF2)3O(CF 2CF2O)2CF2COONa, CF3CF2OCF2CF2OCF2COONH4, CF3CF2O(CF2CF2O)2CF2COONH4, CF3CF2OCF2CF2OCF2COONa, CF3CF2O(CF 2CF2O)2CF2COONa, CF3OCF2CF2CF2OCF2COONH4, CF3OCF2CF2CF2OCF(CF3)COONH4, CF3OCF2CF2CF2OCF2COONa, CF3OCF2CF Fluorine-containing emulsifiers such as 2CF2OCF(CF3)COONa, CF3O(CF2O)3CF2COONH4, CF3O(CF2O)3CF2COONa, CF3OCF(CF3)CF2OCF(CF3)COONH4, CF3OCF(CF3)CF2OCF(CF3)COONa, CF3O(CF2CF2O)2CF2COONH4, CF3O(CF2CF2O)2CF2COONa, C2F5OCF2CF2OCF2COONH4, etc. One emulsifier may be used alone, or two or more emulsifiers may be used in combination. Of these, ammonium perfluorooctanoate, CF3(CF2)3OCF2CF2OCF2COONH4, CF3(CF2)2OCF2CF2OCF2COONH4, CF3CF2OCF2CF2OCF2COONH4, CF3OCF2CF2CF2OCF2COONH4, and C2F5OCF2CF2OCF2COONH4 are preferred. The amount of the emulsifier used is preferably 0.01 to 20 parts by mass, more preferably 0.05 to 15 parts by mass, and particularly preferably 0.1 to 10 parts by mass, relative to 100 parts by mass of the aqueous medium.

[0042] The polymerization reaction conditions, such as pressure and temperature, are appropriately set depending on the monomer composition, the decomposition temperature of the radical polymerization initiator, etc. Usually, the pressure is preferably 0.1 to 20 MPaG, more preferably 0.3 to 10 MPaG, and particularly preferably 0.3 to 5 MPaG. The temperature is preferably 0 to 100°C, more preferably 10 to 90°C, and particularly preferably 20 to 85°C.

[0043] In emulsion polymerization, the fluorine-containing copolymer is obtained as a latex, which can be purified by coagulating it as appropriate by known methods such as addition of a metal salt or an inorganic acid such as hydrochloric acid, sulfuric acid or nitric acid, mechanical shearing or freezing and thawing. In the case of solution polymerization, the product can be purified by washing with an aqueous medium such as methanol or water.

[0044] <Inorganic fillers> Examples of inorganic fillers contained in the fluorine-containing copolymer composition of this embodiment include carbon black, silicon dioxide, aluminum oxide, magnesium oxide, silicon carbide, silicon nitride, aluminum nitride, crystalline zeolite, and nanodiamond. These inorganic fillers may be used alone or in combination of two or more. Among these, from the viewpoint of obtaining a crosslinked product that has abrasion resistance and is less likely to damage mating materials, preferred are carbon black, silicon dioxide, aluminum oxide, silicon carbide, silicon nitride, aluminum nitride, crystalline zeolite, and nanodiamond, more preferred are silicon dioxide, aluminum oxide, silicon carbide, nanodiamond, and magnesium oxide, and particularly preferred are silicon dioxide, silicon carbide, nanodiamond, and magnesium oxide.

[0045] The content of the inorganic filler is not particularly limited, but from the viewpoint of achieving both rubber properties and abrasion resistance, it is preferably 1 to 60 parts by mass, more preferably 3 to 55 parts by mass, and particularly preferably 5 to 50 parts by mass per 100 parts by mass of the fluorine-containing copolymer.

[0046] The average particle size of the inorganic filler is not particularly limited, but from the viewpoint of abrasion resistance and dispersibility of the filler, it is preferably 12,000 nm or less, more preferably 4 to 12,000 nm, and particularly preferably 4 to 50 nm. The "average particle size" here is measured by the method described in the Examples section below.

[0047] <Compound (D)> The fluorine-containing copolymer composition of the present embodiment may or may not contain a compound (D) having two or more structures (d) represented by the following formula (2). The compound (D) serves as a crosslinking agent for the fluorine-containing copolymer, and the fluorine-containing copolymer composition of this embodiment reacts to give a crosslinked product of the fluorine-containing copolymer. By using the compound (D) as a crosslinking agent, the fluorine-containing copolymer of this embodiment can form a crosslinked structure containing an indole ring.

[0048] [ka]

[0049] In formula (2), -a 1 represents a single bond and is bonded to a hydrogen atom, a methyl group, or an aromatic ring which may have a substituent. From the viewpoint of heat resistance of the crosslinked product, the aromatic ring is preferably a monocyclic or condensed ring having 6 to 12 carbon atoms which contains a benzene ring or a naphthalene ring and which may have a heteroatom. The substituent on the aromatic ring is preferably an alkyl group having 1 to 6 carbon atoms, more preferably 1 to 5 carbon atoms, and particularly preferably 1 to 4 carbon atoms. The alkyl group may be linear or branched.

[0050] -b 1 ~-b 5 represents a single bond, and -b1 and -b 5 At least one of the groups is bonded to a hydrogen atom to form an indole ring in a crosslinking reaction. 1 or -b 5 -a 1 may be bonded to an aryl group bonded to form a fused ring containing the nitrogen atom.

[0051] From the viewpoint of ease of synthesis and the heat resistance of the crosslinked fluorinated copolymer of the present embodiment, the compound (D) preferably has one or more structures in which the benzene ring A of one structure (d) is linked to the benzene ring A of another structure (d) via a single bond.

[0052] In addition, from the viewpoint of crosslinking reactivity, the structure (d) is -a 1 Compound (D) has a hydrazinobenzene skeleton in which two structures (d) having the hydrazinobenzene skeleton are -b 1 ~-b 5 It is preferable that the bond is one of the following: Furthermore, compound (D) is more preferably a compound in which the benzene rings A of two hydrazinobenzenes are bonded together by a single bond. The bonding position of the single bond connecting the benzene rings A is -b 1 ~-b 5 If the crosslinked structure is of this type, the crosslinked structure formed will have high thermal stability, and a crosslinked product with better heat resistance can be obtained. Among these, from the viewpoints of the thermal stability of the crosslinked structure to be formed and the ease of obtaining raw materials, compounds in which the hydrazino group is in the para (p-) position relative to the single bond connecting the benzene rings A are preferred, and examples thereof include compounds (CLA-1 to CLA-3) represented by the following formulae:

[0053] [ka]

[0054] CLA-1 can be obtained as a hydrochloride salt by substituting the iodine atom of 4,4'-diiodobiphenyl with a hydrazino group using a known method. CLA-1 is also available commercially. Furthermore, CLA-2 can be synthesized, for example, from compound (12) using sodium nitrite, tin(II) chloride dihydrate, and hydrochloric acid, as shown below. CLA-3 can be synthesized by the method described in the Examples.

[0055] [ka]

[0056] The compound (D) is also preferably one in which two structures (d) are bonded via one or more selected from the group consisting of an oxygen atom, a sulfur atom, a sulfonyl group, a perfluoroalkylene group, a perfluoropolyether group, and a divalent aromatic ring which may have a substituent.

[0057] Other specific examples of the compound (D) are shown below.

[0058] [ka]

[0059] [ka]

[0060] In the composition of this embodiment, the content of compound (D) is preferably 0.1 to 10 parts by mass, more preferably 0.2 to 8 parts by mass, particularly preferably 0.3 to 5 parts by mass, per 100 parts by mass of the fluorocopolymer of this embodiment, from the viewpoint of sufficient heat resistance and rubber properties of the crosslinked product of the fluorocopolymer. Compound (D) may be used alone or in combination of two or more types.

[0061] <Other additives> The fluorine-containing copolymer composition of this embodiment may or may not contain other additives in addition to the fluorine-containing copolymer, inorganic filler, and compound (D), provided that the effects of the present invention are not impaired. Examples of other additives include crosslinking aids, reinforcing agents, scorch retarders, mold release agents, acid acceptors, crown ethers, and dyes. The other additives may be used alone or in combination of two or more.

[0062] (Crosslinking aid) Examples of the crosslinking aid include acid catalysts and base catalysts. These may be used alone or in combination of two or more. The crosslinking aid has the effect of increasing the crosslinking reaction rate of the fluorine-containing copolymer by compound D. The crosslinking reaction rate affects the balance between the moldability of the composition and the heat resistance of the crosslinked product, and if there is no need to increase the crosslinking reaction rate, the crosslinking aid may not be used. From the viewpoint of promoting the formation of arylhydrazone in the system of the fluorine-containing copolymer composition of this embodiment, it is preferable to contain an acid catalyst or a base catalyst, and from the viewpoint of promoting the formation of indole rings, it is preferable to contain at least an acid catalyst. When the fluorine-containing copolymer composition of this embodiment contains an acid catalyst, it is thought that the mutual isomerization of the arylhydrazone formed in the system to enehydrazine is promoted and the formation of the indole ring is also accelerated. Examples of the acid catalyst include protonic acids and Lewis acids, such as aliphatic carboxylic acids (including fluorine-containing fatty acids) such as acetic acid, trifluoroacetic acid, lauric acid, and stearic acid; aromatic carboxylic acids such as benzoic acid; sulfuric acid; zinc chloride; boron trifluoride diethyl ether complex; polyphosphoric acid; sulfonic acids such as p-toluenesulfonic acid and trifluoromethanesulfonic acid; triphenylsulfonium nonafluoro-1-butanesulfonate (TPS-NFBS); and water. The acid catalyst may be used alone or in combination with two or more. Among these, from the viewpoint of crosslinking reactivity, preferred are aliphatic carboxylic acids, aromatic carboxylic acids, polyphosphoric acid, p-toluenesulfonic acid, and triphenylsulfonium nonafluoro-1-butanesulfonate (TPS-NFBS), and more preferred are triphenylsulfonium nonafluoro-1-butanesulfonate (TPS-NFBS) and water. Examples of the base catalyst include Bronsted bases and Lewis bases, such as amine compounds; ammonium compounds; imine compounds; iminium compounds; metal alkoxides; halide salts such as potassium fluoride, sodium fluoride, and cesium fluoride; hydroxide salts such as calcium hydroxide, aluminum hydroxide, potassium hydroxide, and sodium hydroxide; phosphates such as sodium monohydrogen phosphate and sodium dihydrogen phosphate; carbonates such as potassium carbonate; hydrogen carbonates such as sodium hydrogen carbonate; acetates such as sodium acetate; water; and the like.

[0063] The crosslinking aid may be added as an additive to the fluorine-containing copolymer composition, or may be previously converted into a quaternary ammonium salt with compound (D) by a known method. Examples of the counter anion of the quaternary ammonium cation include a carboxylate anion and a sulfonate anion, and from the viewpoint of crosslinking reactivity, a conjugated anion of an acid having an acid dissociation constant of 4 or less in water is preferred.

[0064] (reinforcement material) Examples of reinforcing materials include carbon materials such as fullerene, carbon nanotubes, graphite fluoride, and carbon fluoride; fluoropolymers such as polytetrafluoroethylene, tetrafluoroethylene-fluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and ethylene-tetrafluoroethylene copolymer; barium sulfate; calcium metasilicate; metal oxides such as titanium oxide and yttrium oxide; metal carbides such as aluminum carbide; imide fillers such as polyimide, polyamideimide, and polyetherimide; polyaryletherketones such as polyetheretherketone (PEEK), polyetherketone (PEK), and polyetherketoneketone (PEKK); polyester; polyethersulfone; polyphenylene sulfide; clay; and talc. The reinforcing materials may be used alone or in combination of two or more.

[0065] (scorch retardant) Examples of scorch retarders include phenolic hydroxyl group-containing compounds such as bisphenol A, quinones such as hydroquinone, α-methylstyrene dimers such as 2,4-diphenyl-4-methyl-1-pentene, etc. The scorch retarders may be used alone or in combination of two or more.

[0066] (mold release agent) The releasing agent may be, for example, sodium stearate. The releasing agent may be used alone or in combination of two or more kinds.

[0067] (acid acceptor) Examples of the acid acceptor include aliphatic polyesters, aliphatic metal salts, and oxides of divalent metals such as calcium oxide, zinc oxide, and lead oxide. The acid acceptor may be used alone or in combination of two or more.

[0068] (crown ether) An example of the crown ether is 18-crown-6. The crown ether may be used alone or in combination of two or more kinds.

[0069] (dye) Examples of the dye include inorganic pigments such as zinc oxide and titanium dioxide; and organic pigments having a diketopyrrolopyrrole skeleton, an isoindolinone skeleton, a quinacridone skeleton, an anthraquinone skeleton, a polyarylene skeleton, and an imide skeleton. The dye may be used alone or in combination of two or more. Among these, organic pigments are preferred from the viewpoint of improving heat resistance and plasma resistance due to their ability to quench radicals or redox active species.

[0070] When the fluorocopolymer composition of the present embodiment contains other additives, the total content of the other additives is preferably more than 0 part by mass and not more than 30 parts by mass, more preferably not more than 25 parts by mass, and particularly preferably not more than 20 parts by mass, per 100 parts by mass of the fluorocopolymer.

[0071] [Method of producing fluorine-containing copolymer composition] The method for producing the fluorine-containing copolymer composition of the present embodiment is a method for producing the fluorine-containing copolymer composition of the present embodiment, which comprises kneading the fluorine-containing copolymer and the inorganic filler. The fluorine-containing copolymer composition can be prepared by mixing the above-mentioned components. The components can be mixed by kneading the fluorine-containing copolymer, inorganic filler, and, if necessary, compound (D) and other components by a kneading method using a known rubber mixing device such as a two-roll mill, kneader, Banbury mixer, or extruder. Alternatively, after the components are mixed to obtain a mixture, the mixture may be molded. That is, the fluorine-containing copolymer composition may be a molded product. Specific examples of methods for molding the mixture include compression molding, injection molding, extrusion molding, calendar molding, or a method in which the mixture is dissolved in a solvent and then dipped or coated to form a molded product.

[0072] [Crosslinked composition] The crosslinked composition of this embodiment includes a crosslinked product obtained by crosslinking the fluorocopolymer in the above-mentioned fluorocopolymer composition. The crosslinked composition of this embodiment may be a crosslinked composition obtained by crosslinking the fluorocopolymer in the above-mentioned fluorocopolymer composition to form a crosslinked product. When the above fluorinated copolymer composition contains the compound (D) as a crosslinking agent, the crosslinked product contained in the crosslinked product composition of the present embodiment forms a crosslinked structure containing an indole ring. Crosslinked materials containing a ring structure in the crosslinked structure tend to have better heat resistance than crosslinked materials not containing a ring structure. Furthermore, when the ring structure contained in the crosslinked structure is an indole ring, better heat resistance can be obtained than when the ring structure is a benzene ring, an oxazole ring, or a triazine ring. In particular, both short-term and long-term heat resistance are excellent.

[0073] In the fluorine-containing copolymer composition, the content of the crosslinked product obtained by crosslinking the fluorine-containing copolymer in the composition is not particularly limited, but from the viewpoint of obtaining a crosslinked product composition that has abrasion resistance and is unlikely to damage the mating material, it is preferably 50% by mass or more, more preferably 65% by mass or more, even more preferably 80% by mass or more, and particularly preferably 100% by mass, based on 100% by mass of the crosslinked product composition.

[0074] The crosslinked composition of this embodiment is suitable for use as sealing materials and cushioning materials such as O-rings, V-rings, packings, oil seals, gaskets, diaphragms, and sheets. It can also be suitably used in a variety of applications, including heat-resistant and chemical-resistant sealing materials, heat-resistant and oil-resistant sealing materials, electric wire coating materials, sealing materials for semiconductor devices, corrosion-resistant rubber coating materials, sealing materials for urea-based grease, rubber coating materials, adhesive rubbers, hoses, tubes, calendar sheets (rolls), sponges, rubber rolls, oil drilling components, heat-dissipating sheets, solution-crosslinked products, rubber sponges, bearing seals, linings, automotive insulating sheets, insulating sheets for electronic devices, rubber bands for watches, endoscope gaskets, bellows hoses, water heater gaskets / valves, fenders, fibers and nonwoven fabrics (protective clothing, etc.), board sealing materials, rubber gloves, stators for uniaxial eccentric screw pumps, parts for urea SCR systems, vibration isolators, vibration dampers, sealants, additives for other materials, and toys.

[0075] [Method of producing crosslinked composition] The method for producing the crosslinked composition of this embodiment is a method for producing the crosslinked composition of this embodiment, which comprises primarily heating the fluorocopolymer composition at 80 to 200° C. for 0.1 to 6 hours and, after the primary heating, secondary heating at 200 to 300° C. for 1 to 24 hours. During the primary heating, the fluorocopolymer composition may be appropriately molded. The crosslinked product is obtained by crosslinking the fluorocopolymer in the fluorocopolymer composition, and examples of the method for crosslinking the fluorocopolymer include a method of crosslinking the fluorocopolymer composition by heating, and a method of irradiating with ionizing radiation. Specific examples of the crosslinking method by heating include heat press crosslinking, steam crosslinking and hot air crosslinking, from which a suitable method can be selected taking into consideration the shape and application of the fluorocopolymer composition. Examples of molding methods include compression molding, injection molding, extrusion molding, calendar molding, and a method of dissolving the composition in a solvent and dipping or coating the composition onto a substrate or the like. [Example]

[0076] The present invention will be specifically described below based on examples, but the present invention is not limited to the following examples and various modifications can be made without departing from the gist of the present invention.

[0077] <Compound used> The abbreviations of the various compounds used are explained below. TFE; Tetrafluoroethylene PMVE;CF2=CFOCF3: Perfluoro(methyl vinyl ether) ·8CNVE;(CF2=CFOCF2CF(CF3)OCF2CF2CN) ·C2F5OCF2CF2OCF2COONH4; emulsifier Disodium hydrogen phosphate dodecahydrate; Fujifilm Wako Pure Chemical Industries, Ltd. APS: Ammonium persulfate (polymerization initiator), manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Compound (13): 2,2-bis(4-aminophenyl)hexafluoropropane, manufactured by Tokyo Chemical Industry Co., Ltd. Compound (1): Perfluorovinyloxypolyether carboxylic acid ester TPS-NFBS: Triphenylsulfonium nonafluoro-1-butanesulfonate, manufactured by Tokyo Chemical Industry Co., Ltd. BOAP: 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, manufactured by Tokyo Chemical Industry Co., Ltd. Ultrapure water: for ICP analysis, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Diethyl ether; Fujifilm Wako Pure Chemical Industries, Ltd. Tetrahydrofuran; Fujifilm Wako Pure Chemical Industries, Ltd. 35% by weight methylmagnesium bromide diethyl ether solution; manufactured by Tokyo Chemical Industry Co., Ltd. Tin(II) chloride dihydrate; Fujifilm Wako Pure Chemical Industries, Ltd. Hydrochloric acid; Fujifilm Wako Pure Chemical Industries, Ltd. Table salt: Fujifilm Wako Pure Chemical Industries, Ltd. Nitric acid: Fujifilm Wako Pure Chemical Industries, Ltd. Sodium nitrite; Fujifilm Wako Pure Chemical Industries, Ltd. Sodium bicarbonate; Fujifilm Wako Pure Chemical Industries, Ltd. Anhydrous sodium sulfate; Fujifilm Wako Pure Chemical Industries, Ltd. Sodium hydroxide; Fujifilm Wako Pure Chemical Industries, Ltd. Acetone; Junsei Chemical Co. Chloroform: Fujifilm Wako Pure Chemical Industries, Ltd. <Inorganic fillers used> Inorganic filler 1: Carbon black, average particle size: 450nm, "N990", manufactured by CANCAB Inorganic filler 2: silicon dioxide, average particle size: 12,000 nm, "Carplex #1120", manufactured by Evonik Industries Inorganic filler 3: silicon dioxide, average particle size: 350 nm, "RX50", manufactured by Nippon Aerosil Inorganic filler 4: Aluminum oxide, average particle size: 30 nm, "AKP-G008", manufactured by Sumitomo Chemical Co., Ltd. Inorganic filler 5: silicon carbide, average particle size: 30 nm, "NM-SiC", manufactured by Nanomakers Inorganic filler 6: silicon carbide, average particle size: 450 nm, "Ultradensic DU A-1", manufactured by Resonac Holdings Co., Ltd. Inorganic filler 7: silicon nitride, average particle size: 30 nm, "SN-A00", manufactured by UBE Corporation Inorganic filler 8: Aluminum nitride, average particle size: 200 nm, "E grade", manufactured by Tokuyama Corporation Inorganic filler 9: Crystalline zeolite: Molecular sieves 4A, average particle size: 100 nm, manufactured by Sigma-Aldrich Inorganic filler 10: Nano diamond, average particle size: 4~8nm, manufactured by BEIJING GRISH HITECH CO.,LTD Inorganic filler 11: Magnesium oxide, "Caldic #2000", manufactured by Omi Chemical Industry Co., Ltd.

[0078] [Analysis measurement method] <Nuclear magnetic resonance (NMR) measurement> The synthesized compounds were analyzed using a nuclear magnetic resonance spectrometer ("JNM-AL300", manufactured by JEOL Ltd.; the same applies hereinafter). 1 H-NMR and 19 The structure was analyzed by F-NMR.

[0079] <Mass spectrometry (MS)> Furthermore, the molecular weight was determined using a gas chromatograph mass spectrometer ("GCMS-QP2010 Ultra", manufactured by Shimadzu Corporation; chemical ionization (CI) method).

[0080] <Content of Monomer Constitutional Units in Fluorocopolymer> NMR measurement equipment 1 H-NMR and 19 From the results of F-NMR measurement, the contents (mass ratio and molar ratio) of the monomer constitutional units in the fluorine-containing copolymer were calculated. The measurement samples were 1H-perfluorohexane solutions of a fluorine-containing copolymer and 1,4-bis(trifluoromethyl)benzene (standard substance). The content of PMVE structural units in the fluorine-containing copolymer was calculated from the integral ratio of the peak assigned to the fluorine atoms of the trifluoromethyl group of PMVE to the peak assigned to the fluorine atoms of the trifluoromethyl group of 1,4-bis(trifluoromethyl)benzene. The content of CSM-1 structural units in the fluorinated copolymer was calculated from the integral ratio of the peak assigned to the hydrogen atoms of the methyl groups of the CSM-1 units to the peak assigned to the hydrogen atoms of the aromatic rings of 1,4-bis(trifluoromethyl)benzene. The content of 8CNVE structural units in the fluorine-containing copolymer was calculated from the integral ratio of the peak assigned to the fluorine atom of the difluoromethylene group adjacent to the nitrile group of 8CNVE to the peak assigned to the fluorine atom of the trifluoromethyl group of 1,4-bis(trifluoromethyl)benzene. The content of TFE in the fluorocopolymer was calculated as the remainder of the content of PMVE structural units and the content of CSM-1 structural units. <Average particle size> Using a nanoparticle size distribution and concentration measuring device (model: ViewSizer3000, manufactured by HORIBA Scientific), the particle size (average particle size) at which the cumulative particle volume from the small particle size side in the volume-based cumulative particle size distribution becomes 50% of the total particle volume was determined. However, when the average particle size of the inorganic filler was known at the time of procurement, the known average particle size or particle size was used.

[0081] [Synthesis of Fluorine-Containing Compounds] (Synthesis Example 1) Synthesis of CSM-1

[0082] [ka]

[0083] A 2 L four-neck flask was charged with 107 g (350 mmol) of compound (1) and 750 mL of diethyl ether, and the reaction solution was cooled to -65°C or below in a dry ice / acetone bath. While maintaining the reaction solution at -60°C or below, 436 mL of a 35% by weight solution of methylmagnesium bromide in diethyl ether (approximately 3 mol / L) was added dropwise over 2 hours, and the reaction was continued for an additional 4 hours. While maintaining the reaction solution at -38°C or below, a mixture of 150 mL of 36% by weight hydrochloric acid and 150 mL of tetrahydrofuran, cooled to 5°C, was added dropwise over 2.5 hours. The product was returned to room temperature, and 170 mL of ion-exchanged water was added, followed by separation, and the organic phase was recovered. 170 mL of diethyl ether was added to the aqueous phase for extraction, which was then combined with the previous organic phase. The resulting organic phase was washed with 170 mL of a 5% by mass aqueous solution of sodium bicarbonate and then with 170 mL of saturated saline, and then dried by adding anhydrous sodium sulfate. The residue was removed by vacuum filtration, and then the mixture was concentrated under reduced pressure (27 kPa) at 35°C in an evaporator. The concentrate was transferred to a 200 mL eggplant-shaped flask, fitted with a Vigreux column, and purified by vacuum distillation to obtain 68 g of CSM-1 (yield 68%).

[0084] The data for identifying CSM-1 are as follows: The symbol attached to the fluorine atom (F) corresponds to the symbol in the above formula (I). 1 H-NMR(CDCl3):δ[ppm] 2.46(s,3H) 19 F-NMR(CDCl3):δ[ppm] -85.3(m,2F,F-3),-113.6(dd,1F,J=65.6,82.4Hz,F-1b),-121.4(t,2F,J=9.16Hz,F-5),-121.8(d dt,1F,J=6.10,83.9,112.9,F-1a),-126.5(s,2F,F-4),-135.4(ddt,1F,J=6.10,65.6,112.9,F-2) MS(CI) m / z: 291 (M+H + )

[0085] [Synthesis of crosslinker] (Synthesis Example 2) Synthesis of CLA-3

[0086] [ka]

[0087] A 100 mL four-neck flask was charged with 6.8 mL of 20% by weight hydrochloric acid, cooled in an ice bath, and 1.00 g (2.99 mmol) of compound (13) was added with stirring. While maintaining the reaction solution at 2.0°C or below, an aqueous solution of 0.43 g (6.16 mmol) of sodium nitrite dissolved in 9.5 mL of ion-exchanged water was added dropwise over 2 hours, followed by stirring for an additional 1 hour. Next, a mixture of 3.28 g (14.5 mmol) of tin(II) chloride dihydrate and 4.2 mL of 36% by weight hydrochloric acid was added dropwise over 2 hours, followed by stirring for an additional 30 minutes. The precipitated solid was collected by vacuum filtration and dried under reduced pressure at 35°C to obtain 0.269 g of crude product. 10 mL of chloroform and 6 mL of 0.5 mol / L aqueous sodium hydroxide solution were added to the crude product, and the organic phase was separated. 15 mL of chloroform was added to the aqueous layer for re-extraction, and this was combined with the previous organic phase. Anhydrous sodium sulfate was added to the obtained organic phase for drying. After removing the residue by vacuum filtration, the mixture was concentrated under reduced pressure at 30°C in an evaporator. The concentrate was separated and purified by silica gel column chromatography to obtain 22.8 mg of CLA-3.

[0088] The data for identifying CLA-3 are as follows: The symbols attached to the hydrogen atoms (H) correspond to the symbols in the above formula (II). 1 H-NMR(CDCl3):δ[ppm] 7.2~7.3(m,4H,H-1),6.78(d,4H,J=9.39Hz,H-2),5.31(brs,2H,-NHNH2),3.60(brs,4H,-NHNH2) 19 F-NMR(CDCl3):δ[ppm] -64.8(s,6F,-CF3)

[0089] [Production of Fluorine-Containing Copolymer] (Synthesis Example 3-1) Preparation of Fluorine-Containing Copolymer 3-1 Containing Structural Unit (C) Derived from a Fluorine-Containing Compound A 2.5 L stainless steel pressure reactor equipped with an anchor impeller was degassed and then charged with 0.91 L of ultrapure water, 113 g of a 30 wt% aqueous solution of C2F5OCF2CF2OCF2COONH4, 1.0 g of CSM-1, 10.2 g of a 5 wt% aqueous solution of disodium hydrogen phosphate dodecahydrate, and 2.7 g of acetone. The gas phase was then purged with nitrogen. While stirring at 300 rpm using an anchor impeller, 35.7 g of TFE and 96.7 g of PMVE were pressurized into the reactor, and the internal temperature was raised to 40 °C. The internal pressure of the reactor was 1.12 MPa [gauge]. 60 mL of a 15 wt% aqueous solution of APS was added to initiate polymerization. The molar ratio of the monomers pressurized prior to the start of polymerization (hereinafter referred to as "initial monomer") was TFE:PMVE:CSM-1 = 37.9:61.8:0.3. After the polymerization started, the monomer was injected as follows as the polymerization progressed. Hereinafter, the injection of the monomer after the start of polymerization is referred to as "post-addition," and the monomer injected after the start of polymerization is referred to as "post-added monomer." When the reactor internal pressure dropped to 1.02 MPa [gauge], TFE was injected, and the reactor internal pressure was increased to 1.10 MPa [gauge]. This process was repeated, and every time 18 g of TFE was injected, 0.48 g of CSM-1, 12.3 g of PMVE, and 2 mL of a 30% by mass aqueous solution of C2F5OCF2CF2OCF2COONH4 were injected in this order. When the amount of TFE post-added monomer reached 176 g, the addition of the post-added monomer was stopped. The internal temperature of the reactor was cooled to 10°C to terminate the polymerization reaction, and a latex containing a fluorinated copolymer was obtained. The polymerization time was 510 minutes. The total mass of each post-added monomer was 176 g for TFE, 119 g for PMVE, and 9.4 g for CSM-1, which was converted into a molar ratio of TFE:PMVE:CSM-1=70.1:28.6:1.3. The latex was added to a 3% by mass aqueous solution of nitric acid to coagulate and separate the fluorocopolymer. The fluorocopolymer was filtered, washed with ultrapure water, and vacuum dried at 60°C to obtain a white fluorocopolymer 3-1. The content (molar ratio) of each unit in the obtained fluorocopolymer 3-1 was TFE unit:PMVE unit:CSM-1 unit = 69.6:29.5:0.9. (Synthesis Example 3-2) Preparation of Fluorine-Containing Copolymer 3-2 Not Containing Structural Unit (C) Derived from a Fluorine-Containing Compound A 20 L stainless steel pressure reactor equipped with an anchor impeller was degassed and then charged with 7.2 L of ultrapure water, 880 g of a 30 wt% solution of C2F5OCF2CF2OCF2COONH4, 7.3 g of 8CNVE, and 15.9 g of a 5 wt% aqueous solution of disodium hydrogen phosphate dodecahydrate. The gas phase was then purged with nitrogen. While stirring at 375 rpm using an anchor impeller, 137 g of TFE and 635 g of PMVE were pressurized into the vessel, and the internal temperature was raised to 80 °C. The internal pressure of the reactor was 0.90 MPa [gauge]. 28 mL of a 3 wt% aqueous solution of APS was added to initiate polymerization. The molar ratio of the monomers pressurized prior to the start of polymerization (hereinafter referred to as "initial monomer") was TFE:PMVE:8CNVE = 26.3:73.3:0.4. After the initiation of polymerization, as the polymerization progressed, monomers were injected as follows. Hereinafter, injection of a monomer after the initiation of polymerization will also be referred to as "post-addition," and a monomer injected after the initiation of polymerization will also be referred to as "post-added monomer." When the pressure inside the reactor dropped to 0.89 MPa [gauge], TFE was injected and the pressure inside the reactor was increased to 0.90 MPa [gauge]. This process was repeated, and every time 119.3 g of TFE was injected, 3.7 g of 8CNVE, 74 g of PMVE, and 3.7 g of 8CNVE were injected in this order. When the polymerization rate began to decrease, a 3% by mass aqueous solution of APS was appropriately added. The total amount of the 3% by mass aqueous solution of APS added after the start of polymerization was 35 mL. When the cycle was completed and the total added mass of TFE reached 1073.7 g, 119.3 g of TFE was injected. When the total added mass of post-added TFE reached 1193 g, the addition of the post-added monomer was stopped, the reactor internal temperature was cooled to 10°C, and the polymerization reaction was terminated to obtain a latex containing a fluorinated copolymer. The polymerization time was 375 minutes. The total added masses of the post-added monomers were 1193 g of TFE, 666 g of PMVE, and 66.6 g of 8CNVE, which converted to a molar ratio of TFE:PMVE:8CNVE=74.0:25.0:1.0. The latex was added to a 5% by mass aqueous solution of aluminum potassium sulfate to coagulate and separate the fluorocopolymer. The fluorocopolymer was filtered, washed with ultrapure water, and vacuum dried at 50°C to obtain a white fluorocopolymer 3-2. The content (molar ratio) of each unit in the obtained fluorocopolymer 3-2 was TFE unit:PMVE unit:8CNVE unit = 70.9:28.6:0.5.

[0090] [Manufacturing of cross-linked products] (Production of Examples 1, 3, 5, 7, 9, 11, 13, 15, 17, and 19) The components and amounts (parts by mass) shown in Table 1 were mixed and kneaded with an 8-inch open roll at room temperature for 10 minutes to obtain a mixed fluorine-containing copolymer composition. The obtained fluorine-containing copolymer composition was hot-pressed at 140°C for 3 hours using a hydraulic press (model: SA-301 50T type, manufactured by Tester Sangyo Co., Ltd., ram diameter: 180 mm) to obtain a composition in the form of a flat plate measuring 150 mm in length, 80 mm in width and 2 mm in thickness (primary heating). The plate-shaped compositions were then heated in an oven at 240°C for 3 hours in an air atmosphere (secondary heating), and then cooled to room temperature to obtain crosslinked products of Examples 1, 3, 5, 7, 9, 11, 13, 15, 17, and 19. The following physical properties were measured using the resulting crosslinked product. The measurement results are shown in Table 1.

[0091] (Production of Examples 2, 4, 6, 8, 10, 12, 14, 16, 18, and 20) Crosslinked products of Examples 2, 4, 6, 8, 10, 12, 14, 16, 18, and 20 were obtained in the same manner as in Examples 1, 3, 5, 7, 9, 11, 13, 15, 17, and 19, except that the primary heating and secondary heating were carried out at the temperatures and times shown below. First heating: heated at 180°C for 20 minutes. Secondary heating: After heating at 90°C for 2 hours, the temperature was increased to 200°C over 2 hours and maintained at 200°C for 4 hours. The temperature was then increased to 305°C over 2 hours and further heated at 305°C for 13 hours.

[0092] [Evaluation of physical properties of cross-linked products] The crosslinked product obtained in each example was used as a test piece (150 mm long, 80 mm wide, 2 mm thick) to evaluate the physical properties of the crosslinked product by the following method. The evaluation results are shown in Table 1. Examples 1, 3, 5, 7, 9, 11, 13, 15, 17, and 19 are working examples, and Examples 2, 4, 6, 8, 10, 12, 14, 16, 18, and 20 are comparative examples.

[0093] <Wear resistance evaluation> A ring-on-disc friction and wear test was carried out for 24 hours using a Suzuki-type friction and wear tester (Takachiho Seiki Co., Ltd., "TRI-S100D type") with a SUS304 ring as the mating material under the conditions of a pressure of 1.5 MPa, a speed of 10 m / min, a measurement temperature of 23°C, and a relative humidity of 50%, and the specific wear amount (mm 3 The specific wear rate of the cross-linked material before and after the test was calculated from the rate of change in the weight of the cross-linked material before and after the test. [Evaluation criteria] A: 30.0 mm 3 / (kN·m) or less B: 30.0 mm 3 / (kN m) or more 35.0mm 3 / (kN·m) or less C: 35.0 mm 3 / (kN m) or more In the cases of ratings A and B, it can be said that the abrasion resistance is sufficient. On the other hand, in the case of rating C, it cannot be said that the abrasion resistance is sufficient.

[0094] <Abrasion resistance improvement evaluation> Tests were conducted using the same method as in the evaluation of abrasion resistance described above, and the specific wear rates of crosslinked materials containing the same amount of inorganic filler were compared to evaluate whether abrasion resistance had improved. For this comparison, the specific wear rate of each example corresponding to a comparative example was set at 100, and the specific wear rate of each example corresponding to an embodiment was calculated (comparison combinations: Example 1 and Example 2, Example 3 and Example 4, Example 5 and Example 6, Example 7 and Example 8, Example 9 and Example 10, Example 11 and Example 12, Example 13 and Example 14, Example 15 and Example 16, Example 17 and Example 18, Example 19 and Example 20). A smaller value indicates a better effect compared to the comparative examples. [Evaluation criteria] A: 50 or less B: Over 50 and under 60 C: 60 or more In the cases of ratings A and B, it can be said that the abrasion resistance was sufficiently improved. On the other hand, in the case of rating C, it cannot be said that the abrasion resistance was sufficiently improved.

[0095] <Evaluation of susceptibility to damage to mating materials (friction evaluation)> The test was carried out using the same method as used to evaluate the friction resistance, and the surface condition of the mating material (SUS304 ring) was visually inspected. [Evaluation criteria] 〇: No scratches ×: Scratched In the case of a rating of ◯, it can be said that the mating material is sufficiently unlikely to be damaged. On the other hand, in the case of a rating of ×, it cannot be said that the mating material is hardly damaged.

[0096] [Table 1]

[0097] As can be seen from the evaluation results shown in Table 1, the crosslinked products obtained by crosslinking the fluorine-containing copolymer composition of the present invention (Examples 1, 3, 5, 7, 9, 11, 13, 15, 17, and 19) were found to have excellent abrasion resistance and also to have the property of being less likely to damage the mating material, compared with the crosslinked products obtained by crosslinking a fluorine-containing copolymer composition not of the present invention (Examples 2, 4, 6, 8, 10, 12, 14, 16, 18, and 20).

Claims

1. A fluorine-containing copolymer composition comprising a fluorine-containing copolymer and an inorganic filler, The fluorine-containing copolymer composition, wherein the fluorine-containing copolymer comprises a structural unit (A) derived from tetrafluoroethylene, a structural unit (B) derived from a perfluoroalkyl vinyl ether, and a structural unit (C) derived from a fluorine-containing compound represented by the following formula (1): 【Chemical 1】 [In formula (1), R １ ~R ３ is a fluorine atom. R ４ is a monovalent organic group having 1 to 8 carbon atoms that does not contain a hydrogen atom, a fluorine atom, or a carbonyl group. Z is an oxygen atom. X is a single bond or a difluoromethylene group. Y １ ~Y ４ are each independently a fluorine atom or a trifluoromethyl group. Q is a perfluoroalkylene group having 1 to 8 carbon atoms which may contain an etheric oxygen atom.

2. The fluorine-containing copolymer composition according to claim 1, wherein, based on a total of 100% by mass of the structural units (A) to (C), the structural unit (A) accounts for 10.0 to 99.9% by mass, the structural unit (B) accounts for 0.0 to 70.0% by mass, and the structural unit (C) accounts for 0.1 to 20.0% by mass.

3. 2. The fluorine-containing copolymer composition according to claim 1, wherein the content of said inorganic filler is 1 to 60 parts by mass per 100 parts by mass of said fluorine-containing copolymer.

4. 2. The fluorine-containing copolymer composition according to claim 1, wherein the inorganic filler has an average particle size of 12,000 nm or less.

5. 2. The fluorine-containing copolymer composition according to claim 1, wherein the inorganic filler is at least one selected from the group consisting of carbon black, silicon dioxide, aluminum oxide, magnesium oxide, silicon carbide, silicon nitride, aluminum nitride, crystalline zeolite, and nanodiamond.

6. Further comprising a cross-linking coagent, 2. The fluorine-containing copolymer composition according to claim 1, wherein the crosslinking aid is at least one member selected from the group consisting of water and triphenylsulfonium nonafluoro-1-butanesulfonate.

7. A crosslinked product composition comprising a crosslinked product obtained by crosslinking the fluorocopolymer in the fluorocopolymer composition according to any one of claims 1 to 6.

8. The crosslinked composition according to claim 7 , wherein the crosslinked structure of the crosslinked product contains an indole ring.

9. A method for producing the fluorine-containing copolymer composition according to any one of claims 1 to 6, comprising the steps of: A method for producing a fluorine-containing copolymer composition, which comprises kneading the fluorine-containing copolymer and the inorganic filler.

10. A method for producing the crosslinked composition according to claim 7, comprising: The fluorine-containing copolymer composition, First heating at 80 to 200°C for 0.1 to 6 hours, After the primary heating, the composition is secondarily heated at 200 to 300°C for 1 to 24 hours.

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