Compositions and crosslinks

Abstract

The present invention provides a composition which is a composition containing a perfluoroelastomer and polytetrafluoroethylene, the polytetrafluoroethylene having a melt viscosity of 1.0 x 10 3 ~ 7.0 x 10 6 poise, the polytetrafluoroethylene having a melting point of 322°C or higher, the composition being obtained by co-coagulating the perfluoroelastomer and the polytetrafluoroethylene.

Description

Technical Field

[0001] This invention relates to compositions and crosslinkers. Background Technology

[0002] Previously, in order to improve the physical properties of perfluoroelastomers, it was known that a technique of adding fluororesins to perfluoroelastomers was employed.

[0003] For example, Patent Document 1 describes a composition comprising fluoroplastic particles and amorphous fluoropolymer having an average particle size of less than 500 nm.

[0004] Patent Document 2 discloses a fluorine-based composition for sealing materials, which is obtained by adding an inorganic acid solution to a mixture formed by mixing a suspension of a fluorine elastomer and a suspension of a fluorine resin in a mass ratio of 95:5 to 5:95 and then performing co-precipitation.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Publication No. 2018-531316

[0008] Patent Document 2: Japanese Patent Application Publication No. 2003-26811 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] The purpose of this invention is to provide a composition that yields a crosslinked material that is not easily broken even when compressed at high temperatures, and has excellent plasma resistance and excellent compression set properties.

[0011] Methods for solving problems

[0012] According to the present invention, a composition is provided, which is a composition containing a perfluoroelastomer and polytetrafluoroethylene, wherein the melt viscosity of the polytetrafluoroethylene is 1.0 × 10⁻⁶. 3 Moor ~7.0×10 6 The above-mentioned polytetrafluoroethylene has a melting point of 322°C or higher, and the composition is obtained by co-precipitation of the above-mentioned perfluoroelastomer and the above-mentioned polytetrafluoroethylene.

[0013] The effects of the invention

[0014] According to the present invention, a composition can be provided that yields a crosslinked material that is not easily broken even when compressed at high temperatures, and has excellent plasma resistance and excellent compression set properties. Detailed Implementation

[0015] The specific embodiments of the present invention will be described in detail below, but the present invention is not limited to the following embodiments.

[0016] The composition of the present invention contains a perfluoroelastomer and polytetrafluoroethylene (PTFE).

[0017] Compared to existing techniques that add fluoroplastics or fluororesins to perfluoroelastomers, techniques that add fillers such as inorganic particles to perfluoroelastomers have advantages such as less likelihood of particle generation. However, there is a need for a perfluoroelastomer composition that can produce a crosslinked material with excellent plasma resistance, resistance to breakage even under sustained compression at high temperatures, and easy shape recovery after release from compression.

[0018] The inventors have discovered that by selecting PTFE as the fluoropolymer, and further appropriately selecting the melt viscosity and melting point of PTFE, and by selecting a method for co-precipitating perfluoroelastomer and PTFE as the method for preparing the composition, the crosslinked product obtained by crosslinking such a composition is not easily broken even when compressed at high temperatures, and has excellent plasma resistance and excellent compression set characteristics, thus completing the composition of the present invention.

[0019] (PTFE)

[0020] The PTFE contained in the composition of the present invention has a melt viscosity of 1.0 × 10⁻⁶. 3 Moor ~7.0×10 6 Poiseuille. The preferred melt viscosity is 1.0 × 10⁻⁶. 4 More than 10 berths, preferably 1.0 × 10 berths. 5 Above 5.0 × 10 berths, preferably 5.0 × 10 berths. 6 Below 10 berths, 3.0 × 10 berths is more preferred. 6 Below 1000 rpm, it is further preferred to be 1.0 × 10⁻⁶ rpm 6 Below the moor.

[0021] By using PTFE with a melt viscosity within the aforementioned range, crosslinked compositions exhibiting excellent plasma resistance and superior compression set properties can be obtained. If the melt viscosity of PTFE is too high, the compression set properties of the crosslinked composition cannot be sufficiently improved. For example, prolonged compression of the crosslinked composition at temperatures around 300°C can lead to compression damage or difficulty in restoring the crosslinked composition to its original shape. PTFE with excessively low melt viscosity may produce high-temperature volatile components, thus sometimes making it unsuitable for crosslinked compositions used at high temperatures (e.g., around 300°C).

[0022] PTFE with melt viscosity within the aforementioned range has a low molecular weight, for example, PTFE with a number average molecular weight of 600,000 or less. "High molecular weight PTFE" with a number average molecular weight exceeding 600,000 exhibits the fibrillation characteristics characteristic of PTFE (see, for example, Japanese Patent Application Publication No. 10-147617). High molecular weight PTFE has a high melt viscosity and is non-melt processable. The PTFE contained in the compositions of the present invention preferably does not exhibit fibrillation characteristics to the extent suitable for paste extrusion molding. The melt viscosity and number average molecular weight of PTFE can be adjusted by modifying the polymerization conditions of TFE during PTFE manufacturing or by irradiating PTFE with electron beams.

[0023] Melt viscosity was measured according to ASTM D 1238 using a flow tester (manufactured by Shimadzu Corporation) and The number-average molecular weight was measured by holding a 2g sample, preheated to 380°C for 5 minutes, at the aforementioned temperature under a load of 0.7MPa. The number-average molecular weight can be calculated from the melt viscosity determined using the above method.

[0024] The PTFE contained in the composition of the present invention has a melting point of 322°C or higher. Preferably, the melting point is 323°C or higher, more preferably 324°C or higher, even more preferably 325°C or higher, preferably 333°C or lower, more preferably 332°C or lower, and even more preferably 330°C or lower.

[0025] When the melting point of PTFE is too low, the compression set properties of the cross-linked material cannot be sufficiently improved. For example, when the cross-linked material is compressed for a long time at a high temperature of around 300°C, PTFE melts, resulting in the problem that the shape of the cross-linked material is difficult to restore.

[0026] The melting point of PTFE can be determined as follows: Using a Hitachi High-Tech Corporation X-DSC7000 (DSC) differential scanning calorimeter, approximately 3 mg of PTFE (after temperature calibration with indium and lead, and without being heated to a temperature above 300°C) is placed in an aluminum dish. Under a nitrogen flow of 40 ml / min, the temperature range of 230°C to 350°C is increased at a rate of 10°C / min, and differential scanning calorimetry is performed. The temperature corresponding to the minimum point of the melting curve in the above range is taken as the melting point.

[0027] The preferred specific surface area of ​​PTFE is 0.5 m². 2 / g~20m 2 / g. Specific surface area was determined using a surface analyzer (trade name: BELSORP-miniII, manufactured by Microtrac BEL) as the carrier gas, using a mixture of 30% nitrogen and 70% helium, cooled with liquid nitrogen, and determined by the BET method.

[0028] The average primary particle size of PTFE is preferably 10 nm to 1000 μm, more preferably 100 nm or more, even more preferably 200 nm or more, more preferably 100 μm or less, even more preferably 10 μm or less, particularly preferably 1 μm or less, and particularly preferably 500 nm or less.

[0029] The average primary particle size was calculated as follows: After determining the correlation between the transmittance of 550 nm light incident on a specified unit containing an aqueous PTFE dispersion with a solid content adjusted to 0.15% by mass and the number-average primary particle size calculated by measuring the directional diameter using a transmission electron microscope, the transmittance of the obtained sample was substituted into the above correlation to calculate the average primary particle size (standard curve method).

[0030] PTFE can be a homopolymer of tetrafluoroethylene (TFE) or a modified PTFE containing TFE units and modified monomer units that can copolymerize with TFE. From the perspective of further improving the compression set properties of the crosslinked compound, PTFE containing TFE units and modified monomer units that can copolymerize with TFE is preferred.

[0031] The content of the modified monomer unit of PTFE is 0 mol% to 0.10 mol% relative to all monomer units, more preferably 0.02 mol% or more, even more preferably 0.05 mol% or more, and more preferably 0.09 mol% or less.

[0032] In this invention, a modified monomer unit refers to a portion of the PTFE molecular structure derived from modified monomers, while a total monomer unit refers to the portion of the PTFE molecular structure derived from all monomers. The content of modified monomer units is determined by infrared spectroscopy or NMR (nuclear magnetic resonance).

[0033] As a modifying monomer in modified PTFE, there are no particular limitations as long as it can copolymerize with TFE. Examples include perfluoroolefins such as hexafluoropropylene [HFP]; chlorofluoroolefins such as trifluorochloroethylene [CTFE]; hydrofluoroolefins such as trifluoroethylene and vinylidene fluoride [VDF]; perfluorovinyl ethers; and perfluoroalkyl ethylene. In addition, one or more modifying monomers can be used.

[0034] There are no particular limitations on the above-mentioned perfluorovinyl ethers; for example, general formula (I) can be cited:

[0035] CF2 = CF - ORf(I)

[0036] (where Rf represents a perfluorinated organic group) and other perfluorinated unsaturated compounds. In this specification, the term "perfluorinated organic group" refers to an organic group in which all hydrogen atoms bonded to carbon atoms are replaced by fluorine atoms. The aforementioned perfluorinated organic group may have ether oxygen.

[0037] Examples of perfluorovinyl ethers include perfluoro(alkylvinyl ether) [PAVE], in which Rf represents a perfluoroalkyl group having 1 to 10 carbon atoms. The preferred number of carbon atoms in the perfluoroalkyl group is 1 to 5.

[0038] Examples of perfluoroalkyl groups in the above-mentioned PAVE include perfluoromethyl, perfluoroethyl, perfluoropropyl, perfluorobutyl, perfluoropentyl, and perfluorohexyl. Perfluoromethyl vinyl ether [PMVE] with perfluoromethyl as the perfluoroalkyl group or perfluoropropyl vinyl ether [PPVE] with perfluoropropyl as the perfluoroalkyl group are preferred.

[0039] Further examples of the aforementioned perfluorovinyl ethers include:

[0040] In general formula (I), Rf is a perfluorinated (alkoxyalkyl) substance with 4 to 9 carbon atoms, and Rf is the following formula:

[0041] [Chemistry 1]

[0042]

[0043] (where m represents 0 or an integer from 1 to 4) The substance with the group shown, Rf, is as follows:

[0044] CF3CF2CF2-(O-CF(CF3)-CF2) n -

[0045] Substances containing groups such as (where n represents an integer from 1 to 4).

[0046] There are no particular limitations on perfluoroalkyl ethylene; examples include perfluorobutylethylene (PFBE), perfluorohexylethylene, and perfluorooctylethylene.

[0047] As the modifying monomer in modified PTFE, it is preferred to select at least one monomer from the group consisting of HFP, CTFE, VDF, perfluorovinyl ether, PFBE and ethylene, more preferably at least one monomer from the group consisting of HFP and perfluorovinyl ether, and even more preferably at least one monomer from the group consisting of HFP, PMVE and PPVE.

[0048] From the viewpoint of obtaining a crosslinked compound with superior plasma resistance and superior compression set properties, the PTFE content in the composition is preferably 1 to 100 parts by weight relative to 100 parts by weight of the perfluoroelastomer, more preferably 5 parts by weight or more, even more preferably 10 parts by weight or more, particularly preferably 15 parts by weight or more, more preferably 70 parts by weight or less, and even more preferably 60 parts by weight or less. From the viewpoint of obtaining a crosslinked compound with superior compression set properties, the PTFE content in the composition is even more preferably 55 parts by weight or less, and particularly preferably 50 parts by weight or less.

[0049] (Perfluoroelastomers)

[0050] The compositions of the present invention contain a perfluoroelastomer. Since the compositions of the present invention contain a perfluoroelastomer as a fluororubber, when the compositions are crosslinked, crosslinked products with excellent plasma resistance and excellent compression set properties can be obtained.

[0051] In this invention, a perfluorinated elastomer refers to a fluoropolymer that is a fluoropolymer in which the content of perfluorinated monomer units relative to all monomer units is 90 mol% or more, preferably 91 mol% or more, has a glass transition temperature of 20°C or less, has a melting peak (ΔH) of 4.5 J / g or less, and further, has a fluorine atom concentration of 71 wt% or more, preferably 71.5 wt% or more. In this invention, the concentration of fluorine atoms in the fluoropolymer is determined by calculating the concentration (wt%) of fluorine atoms in the fluoropolymer based on the type and content of each monomer constituting the fluoropolymer.

[0052] In this invention, a perfluorinated monomer refers to a monomer that does not contain carbon-hydrogen bonds in its molecule. The perfluorinated monomer may also be a monomer in which, in addition to carbon and fluorine atoms, several fluorine atoms bonded to carbon atoms are replaced by chlorine atoms, or it may be a monomer that, in addition to carbon atoms, also contains nitrogen, oxygen, sulfur, phosphorus, boron, or silicon atoms. Preferably, the perfluorinated monomer in which all hydrogen atoms are replaced by fluorine atoms is a preferred embodiment. The perfluorinated monomer does not contain monomers that provide crosslinking sites.

[0053] Monomers that provide crosslinking sites refer to monomers (curing site monomers) that have crosslinking groups that provide crosslinking sites for the fluoropolymer to form crosslinks by a curing agent.

[0054] In this invention, the content of each monomer constituting the perfluorinated elastomer can be calculated by appropriately combining NMR, FT-IR, elemental analysis, fluorescence X-ray analysis, and other known methods according to the type of monomer.

[0055] The perfluorinated monomer, which provides the perfluorinated monomer unit constituting the perfluorinated elastomer, is preferably selected from...

[0056] Tetrafluoroethylene [TFE],

[0057] Hexafluoropropylene [HFP],

[0058] General formula (13): CF2 = CF - ORf 13

[0059] (where Rf) 13 Fluorinated monomers (representing perfluoroalkyl groups with 1 to 8 carbon atoms)

[0060] General formula (14): CF2=CFOCF2ORf 14

[0061] (where Rf) 14 Fluorinated monomers, including straight-chain or branched perfluoroalkyl groups having 1 to 6 carbon atoms, cyclic perfluoroalkyl groups having 5 to 6 carbon atoms, and straight-chain or branched perfluorooxyalkyl groups having 2 to 6 carbon atoms containing 1 to 3 oxygen atoms, and...

[0062] General formula (15): CF2=CFO(CF2CF(Y 15 )O) m (CF2) n F

[0063] (where Y) 15 Represents a fluorine atom or a trifluoromethyl group. m is an integer from 1 to 4. n is an integer from 1 to 4. This group contains at least one fluorine-containing monomer.

[0064] As a perfluoroelastomer, a perfluoroelastomer containing TFE units is preferred, for example, preferably at least one of the group consisting of a fluorinated monomer copolymer of TFE / general formula (13), (14) or (15) and a fluorinated monomer / monomer copolymer of TFE / general formula (13), (14) or (15) that provides a crosslinking site.

[0065] Regarding its composition, in the case of TFE / perfluoro(methyl vinyl ether) (PMVE) copolymer, it is preferably 45-90 / 10-55 (mol%), more preferably 55-80 / 20-45, further preferably 55-70 / 30-45, and most preferably 56-69.5 / 30.5-44.

[0066] In the case of a TFE / PMVE monomer copolymer providing crosslinking sites, the preferred composition is 45–89.9 / 10–54.9 / 0.01–4 (mol%), more preferably 55–77.9 / 20–49.9 / 0.1–3.5, further preferably 55–69.8 / 30–44.8 / 0.2–3, and most preferably 55.3–69.5 / 30.3–44.5 / 0.2–2.8.

[0067] In the case of TFE / fluorinated monomer copolymers of general formulas (13), (14) or (15) with 4 to 12 carbon atoms, the preferred value is 50 to 90 / 10 to 50 (mol%), more preferably 60 to 88 / 12 to 40, further preferably 65 to 85 / 15 to 35, and most preferably 66 to 84 / 16 to 34.

[0068] In the case of a TFE / fluorinated monomer / monomer copolymer of general formula (13), (14) or (15) having 4 to 12 carbon atoms, the preferred ratio is 50 to 89.9 / 10 to 49.9 / 0.01 to 4 (mol%), more preferably 60 to 87.9 / 12 to 39.9 / 0.1 to 3.5, further preferably 65 to 84.8 / 15 to 34.8 / 0.2 to 3, and most preferably 66 to 84.3 / 15.5 to 33.8 / 0.2 to 2.8.

[0069] If it falls outside this composition range, it loses its properties as a rubber elastomer and tends to exhibit properties closer to those of a resin.

[0070] As a perfluorinated elastomer, it is preferably selected from at least one of the following groups: a fluorinated monomer copolymer of TFE / general formula (15) / monomer copolymer providing crosslinking sites, a fluorinated monomer copolymer of TFE / general formula (15), a fluorinated monomer copolymer of TFE / general formula (13), and a fluorinated monomer copolymer of TFE / general formula (13) / monomer copolymer providing crosslinking sites.

[0071] Other examples of perfluorinated elastomers include those described in International Publication No. 97 / 24381, Japanese Patent Publication No. 61-57324, Japanese Patent Publication No. 4-81608, and Japanese Patent Publication No. 5-13961.

[0072] Monomers that provide crosslinking sites refer to monomers (curing site monomers) that have crosslinking groups that provide crosslinking sites for the formation of crosslinks in perfluoroelastomers by crosslinking agents.

[0073] Examples of monomers that provide cross-linking sites include

[0074] General formula (16): CX 4 2 = CX5 R f 2 X 6

[0075] (where X) 4 X 5 Each is independently H, F, or an alkyl group having 1 to 5 carbon atoms, Rf 2 X is a straight-chain or branched alkylene or oxidized alkylene that may have one or more ether-bonded oxygen atoms, may have an aromatic ring, and whose hydrogen atoms may be partially or completely replaced by fluorine atoms. 6 The monomer may be represented by an iodine atom, bromine atom, nitrile group, carboxyl group, alkoxycarbonyl group, hydroxyl group, vinyl group, azide group, sulfonyl azide group, carbonyl azide group, or alkynyl group. The alkynyl group may be ethynyl.

[0076] As the monomer providing the crosslinking site, preferably selected from...

[0077] General formula (17): CX 16 2 = CX 16 -Rf 16 CHR 16 X 17

[0078] (where X) 16 Each can be independently a hydrogen atom, a fluorine atom, or CH3, Rf 16 It is a fluoroalkylene, perfluoroalkylene, fluoro(poly)oxyalkylene, or perfluoro(poly)oxyalkylene, R 16 For hydrogen atoms or CH3, X 17 Fluorine-containing monomers (represented by iodine or bromine atoms)

[0079] General formula (18): CX 16 2 = CX 16 -Rf 17 X 17

[0080] (where X) 16 Each can be independently a hydrogen atom, a fluorine atom, or CH3, Rf 17 It is a fluoroalkylene, perfluoroalkylene, fluoro(poly)oxyalkylene, or perfluoro(poly)oxyalkylene, X 17 Fluorine-containing monomers (represented by iodine or bromine atoms)

[0081] General formula (19): CF2 = CFO(CF2CF(CF3)O) m (CF2) n -X 18

[0082] (In the formula, m is an integer from 0 to 5, n is an integer from 1 to 3, X)18 Fluorine-containing monomers represented by cyano, azide, sulfonyl azide, carbonyl azide, carboxyl, alkoxycarbonyl, alkynyl, iodine atom, bromine atom, or CH2I)

[0083] General formula (20): CH2=CFCF2O(CF(CF3)CF2O) m (CF(CF3)) n -X 19

[0084] (In the formula, m is an integer from 0 to 5, n is an integer from 1 to 3, X) 19 Fluorine-containing monomers represented by cyano, carboxyl, alkoxycarbonyl, iodine atom, bromine atom, or CH2OH) and

[0085] General formula (21): CR 20 2 = CR 20 -Z-CR 20 =CR 20 2

[0086] (where R is in the formula) 20 Each is independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Z is a straight-chain or branched alkylene group having or not having oxygen atoms and having 1 to 18 carbon atoms, a cycloalkylene group having 3 to 18 carbon atoms, an at least partially fluorinated alkylene group having 1 to 10 carbon atoms, or an alkylene oxide group, or

[0087] -(Q) p -CF₂O-(CF₂CF₂O) m (CF2O) n -CF2-(Q) p -

[0088] (In the formula, Q is an alkylene or alkylene oxide. p is 0 or 1. m / n is 0.2 to 5) The monomers shown are (per)fluoropolyalkylene oxides with a molecular weight of 500 to 10000.

[0089] X 16 Preferably, it contains fluorine atoms. Rf 16 and Rf 17 Preferably, it is a perfluoroalkylene group having 1 to 5 carbon atoms. 16 Preferably, it contains hydrogen atoms. X 18 Preferably, it consists of a cyano group, an alkoxycarbonyl group, an iodine atom, a bromine atom, or -CH2I. X 19 Preferably, it is a cyano group, an alkoxycarbonyl group, an iodine atom, a bromine atom, or -CH2OH.

[0090] The monomers providing the crosslinking sites are preferably selected from CF2=CFOCF2CF(CF3)OCF2CF2CN, CF2=CFOCF2CF(CF3)OCF2CF2COOH, CF2=CFOCF2CF(CF3)OCF2CF2CH2I, CF2=CFOCF2CF2CH2I, CH2=CFCF2OCF(CF3)CF2OCF(CF3)CN, CH2=CFCF2OCF(CF3)CF2OCF(CF3)COOH, and CH2=CFCF2O At least one of the following groups: CF(CF3)CF2OCF(CF3)CH2OH, CH2=CHCF2CF2I, CH2=CH(CF2)2CH=CH2, CH2=CH(CF2)6CH=CH2, CF2=CFO(CF2)3CN, and CF2=CFO(CF2)5CN; more preferably, at least one of the following groups: CF2=CFOCF2CF(CF3)OCF2CF2CN, CF2=CFO(CF2)5CN, and CF2=CFOCF2CF2CH2I.

[0091] From the perspective of excellent compression set characteristics at high temperatures, the glass transition temperature of the perfluoroelastomer is preferably -30°C or higher, more preferably -20°C or higher, and even more preferably -10°C or higher. Furthermore, from the perspective of good cold resistance, it is preferably below 10°C, more preferably below 5°C, and even more preferably below 0°C.

[0092] The glass transition temperature mentioned above can be determined as follows: Using a differential scanning calorimeter (Hitachi High Technology Co., Ltd., X-DSC7000), a 3mg sample is heated at 10℃ / min to obtain a DSC curve. The temperature of the midpoint between the extension of the baseline representing the second-order phase transition of the DSC curve and the tangent at the inflection point of the DSC curve is determined and taken as the glass transition temperature mentioned above.

[0093] For perfluoroelastomers, from the perspective of good heat resistance, the Mooney viscosity ML(1+20) at 170°C is preferably 30 or more, more preferably 40 or more, and even more preferably 50 or more. Furthermore, from the perspective of good processability, it is preferably 100 or less, more preferably 90 or less, and even more preferably 80 or less.

[0094] The Mooney viscosity described above can be measured at 170°C using a Mooney viscometer MV2000E manufactured by ALPHATECHNOLOGIES, according to JIS K6300.

[0095] Perfluorinated elastomers can be manufactured using conventional methods, but iodine or bromine compounds can also be used as chain transfer agents to achieve narrow molecular weight distributions, ease of molecular weight control, and the ability to introduce iodine or bromine atoms to the ends of the polymer. Examples of polymerization methods using iodine or bromine compounds include emulsification polymerization (iodine transfer polymerization) carried out under pressure in an aqueous medium in a substantially oxygen-free environment in the presence of iodine or bromine compounds. Representative examples of the iodine or bromine compounds used include those with the following general formula:

[0096] R 21 I x Br y

[0097] (In the formula, x and y are integers from 0 to 2 and satisfy 1≤x+y≤2, R) 21 It is a saturated or unsaturated fluorocarbon or chlorofluorocarbon group with 1 to 16 carbon atoms, or a hydrocarbon group with 1 to 3 carbon atoms. 21 Compounds (with or without oxygen atoms). Iodine or bromine atoms are introduced into the polymer using iodine or bromine compounds, serving as crosslinking points.

[0098] Examples of iodine and bromine compounds include, for instance, 1,3-diiodoperfluoropropane, 2-iodoperfluoropropane, 1,3-diiodo-2-chloroperfluoropropane, 1,4-diiodoperfluorobutane, 1,5-diiodo-2,4-dichloroperfluoropentane, 1,6-diiodoperfluorohexane, 1,8-diiodoperfluorooctane, 1,12-diiodoperfluorododecane, 1,16-diiodoperfluorohexadecane, diiodomethane, 1,2-diiodoethane, 1,3-diiodo-n-propane, CF₂Br₂, BrCF₂CF₂Br, CF₃CFBrCF₂Br, and CFClBr₂. BrCF2CFClBr, CFBrClCFClBr, BrCF2CF2CF2Br, BrCF2CFBrOCF3, 1-bromo-2-iodoperfluoroethane, 1-bromo-3-iodoperfluoropropane, 1-bromo-4-iodoperfluorobutane, 2-bromo-3-iodoperfluorobutane, 3-bromo-4-iodoperfluoro-1-butene, 2-bromo-4-iodoperfluoro-1-butene, monoiodomonobromine substituted derivatives of benzene, diiodomonobromine substituted derivatives, and (2-iodoethyl) and (2-bromoethyl) substituted derivatives, etc., these compounds can be used alone or in combination with each other.

[0099] Among these, 1,4-diiodoperfluorobutane, 1,6-diiodoperfluorohexane, and 2-iodoperfluoropropane are preferred in terms of polymerization reactivity, crosslinking reactivity, and ease of acquisition.

[0100] Perfluorinated elastomers preferably have cyano (-CN) groups. Perfluorinated elastomers with cyano (-CN) groups are cross-linked by forming triazine rings through cyclization trimerization of the cyano group, or by forming imidazole rings using tetraamine compounds as cross-linking agents. These perfluorinated elastomers can impart excellent compression set properties and heat resistance to the cross-linked products.

[0101] The aforementioned perfluorinated elastomers containing cyano groups preferably have cyano groups (-CN groups) at the ends of the main chain and / or in the side chains.

[0102] As a perfluoroelastomer having cyano (-CN) groups at the end of the main chain and / or on the side chains, examples include copolymers of TFE / fluorinated monomers / monomers providing crosslinking sites shown in general formulas (13), (14), or (15), where the monomer providing the crosslinking site is a monomer having a cyano (-CN) group. In this case, from the perspective of good crosslinking properties and heat resistance, the content of monomer units having cyano (-CN) groups relative to the total amount of TFE units and fluorinated monomer units shown in general formulas (13), (14), and (15) can be 0.1 mol% to 5 mol%, or 0.3 mol% to 3 mol%. More preferred compositions are as described above.

[0103] In addition, examples of monomers containing a cyano group (-CN group) include:

[0104] Formula: CY 1 2 = CY 1 (CF2) n -CN

[0105] (where Y) 1 Each atom is independently either a hydrogen atom or a fluorine atom, where n is an integer from 1 to 8.

[0106] Formula: CF2=CFCF2Rf 8 -CN

[0107] (where Rf) 8 For -(OCF2) n -or-(OCF(CF3)) n - (n is an integer from 0 to 5)

[0108] Formula: CF2=CFCF2(OCF(CF3)CF2) m (OCH2CF2CF2) n OCH2CF2-CN

[0109] (In the formula, m is an integer from 0 to 5, and n is an integer from 0 to 5)

[0110] Equation: CF2=CFCF2(OCH2CF2CF2) m (OCF(CF3)CF2)n OCF(CF3)-CN

[0111] (In the formula, m is an integer from 0 to 5, and n is an integer from 0 to 5)

[0112] Formula: CF2=CF(OCF2CF(CF3)) m O(CF2) n -CN

[0113] (In the formula, m is an integer from 0 to 5, and n is an integer from 1 to 8)

[0114] Formula: CF2=CF(OCF2CF(CF3)) m -CN

[0115] (In the formula, m is an integer from 1 to 5)

[0116] Formula: CF2=CFOCF2(CF(CF3)OCF2) n CF(-CN)CF3

[0117] (In the formula, n is an integer from 1 to 4)

[0118] Formula: CF2 = CFO(CF2) n OCF(CF3)-CN

[0119] (In the formula, n is an integer from 2 to 5)

[0120] Formula: CF2 = CFO(CF2) n -(C6H4)-CN

[0121] (In the formula, n is an integer from 1 to 6)

[0122] Formula: CF2=CF(OCF2CF(CF3)) n OCF2CF(CF3)-CN

[0123] (In the formula, n is an integer from 1 to 2)

[0124] Formula: CH2=CFCF2O(CF(CF3)CF2O) n CF(CF3)-CN

[0125] (In the formula, n is an integer from 0 to 5)

[0126] Formula: CF2 = CFO(CF2CF(CF3)O) m (CF2) n -CN

[0127] (In the formula, m is an integer from 0 to 5, and n is an integer from 1 to 3)

[0128] Formula: CH2=CFCF2OCF(CF3)OCF(CF3)-CN

[0129] Formula: CH2=CFCF2OCH2CF2-CN

[0130] Formula: CF2 = CFO(CF2CF(CF3)O) m CF2CF(CF3)-CN

[0131] (In the formula, m is an integer greater than or equal to 0)

[0132] Formula: CF2=CFOCF(CF3)CF2O(CF2) n -CN

[0133] (In the formula, n is an integer greater than or equal to 1)

[0134] Formula: CF2=CFOCF2OCF2CF(CF3)OCF2-CN

[0135] Formula: CF2 = CFO(CF2)3CN

[0136] Formula: CF2 = CFO(CF2)5CN

[0137] The monomers shown can be used individually or in any combination.

[0138] Of the above, the preferred option is...

[0139] Formula: CF2=CF(OCF2CF(CF3)) m O(CF2) n -CN

[0140] (where m is an integer from 0 to 5 and n is an integer from 1 to 8) The monomer shown is more preferably CF2=CFOCF2CF(CF3)OCF2CF2CN.

[0141] These perfluorinated elastomers can be manufactured using conventional methods.

[0142] Specific examples of this perfluoroelastomer include fluororubber as described in International Publication No. 97 / 24381, Japanese Patent Publication No. 61-57324, Japanese Patent Publication No. 4-81608, and Japanese Patent Publication No. 5-13961.

[0143] (Co-precipitation)

[0144] The compositions of the present invention are obtained by co-precipitating a perfluoroelastomer with PTFE. By using the co-precipitation method to prepare the composition, and then crosslinking the composition, a crosslinked product with excellent plasma resistance and excellent compression set properties can be obtained. When the composition is prepared by methods other than co-precipitation, such as dry mixing, and then crosslinked, the plasma resistance and compression set properties of the crosslinked product are not sufficiently improved. For example, when the crosslinked product is irradiated with NF3 plasma, it may be cut; or when the crosslinked product is compressed for a long time at a high temperature of around 300°C, it may be crushed due to compression; or even after release from compression, the shape of the crosslinked product may be difficult to restore.

[0145] When considering the combination of perfluorinated elastomers and PTFE for co-precipitation, the selection should be based on the target function, taking into account factors such as whether their precipitation properties are similar and whether they have polymer affinity.

[0146] As a method for co-precipitating perfluoroelastomers and PTFE, examples include methods for preparing an aqueous dispersion containing perfluoroelastomers and PTFE and co-precipitating the perfluoroelastomers and PTFE in the resulting aqueous dispersion.

[0147] Methods for preparing aqueous dispersions include mixing an aqueous dispersion containing a perfluoroelastomer with an aqueous dispersion containing PTFE, mixing powdered perfluoroelastomer with an aqueous dispersion containing PTFE, and mixing powdered PTFE with an aqueous dispersion containing a perfluoroelastomer.

[0148] When mixing an aqueous dispersion containing perfluoroelastomer with an aqueous dispersion containing PTFE, the temperature of each aqueous dispersion is preferably 10°C or higher, more preferably 15°C or higher, even more preferably 20°C or higher, preferably 60°C or lower, and even more preferably 50°C or lower.

[0149] As a method for co-precipitating perfluoroelastomer and PTFE in the thus obtained aqueous dispersion, methods such as mixing the aqueous dispersion with a precipitating agent and freezing can be cited. As the precipitating agent, known precipitating agents such as acids can be used, for example, aluminum salts, calcium salts, or magnesium salts. Organic precipitating agents include ammonium acetate and ammonium carbonate, while inorganic acid precipitating agents include hydrochloric acid, nitric acid, hydrofluoric acid, sulfuric acid, and trifluoroacetic acid. Among these, using an inorganic acid precipitating agent results in a lower metal content and cleaner composition. Precipitation does not damage the crosslinking sites such as cyano groups in the perfluoroelastomer. When the composition is crosslinked, a crosslinked product with a high crosslinking density can be obtained, exhibiting excellent plasma resistance and excellent compression set properties.

[0150] The temperature at which the aqueous dispersion is mixed with the precipitant is preferably 10°C or higher, more preferably 15°C or higher, even more preferably 20°C or higher, preferably 60°C or lower, and even more preferably 50°C or lower. The temperature at which the aqueous dispersion is mixed with the precipitant can be the temperature of the mixture obtained by mixing. When mixing an aqueous dispersion with an aqueous solution containing the precipitant, the temperature at which the aqueous dispersion is mixed with the precipitant can be adjusted by adjusting the temperatures of the aqueous dispersion and the aqueous solution.

[0151] The composition obtained by co-precipitation can be washed with water to remove small amounts of buffer solution, salt, and other impurities present in the composition. The washed composition is then dried using a hot air furnace, vacuum dryer, or similar equipment. The drying temperature is preferably 40°C or higher, more preferably 50°C or higher, even more preferably 60°C or higher, preferably 200°C or lower, more preferably 150°C or lower, and even more preferably 100°C or lower.

[0152] The morphology of the composition obtained after co-precipitation is not particularly limited and can be gum, crumb, powder, granules, etc., preferably gum or crumb. Gum refers to small granular blocks composed of the composition, while crumb refers to the amorphous block morphology formed by the fusing of perfluoroelastomers in the composition with each other at room temperature, which cannot maintain the small granular shape of gum.

[0153] <Other Ingredients>

[0154] The compositions of the present invention may contain components other than perfluoroelastomers and PTFE. Compositions containing other components can be prepared by adding these components during the co-precipitation of the perfluoroelastomer and PTFE, or by mixing the co-precipitated composition with other components after co-precipitation of the perfluoroelastomer and PTFE. Mixing can be carried out using conventional polymer processing machinery, such as open mills, Banbury mixers, kneaders, closed mixers, etc.

[0155] Other components include, for example, fillers.

[0156] Examples of fillers include imide-based fillers with imide structures such as polyimide, polyamide-imide, and polyether-imide; organic fillers made of engineering plastics such as polyarylate, polysulfone, polyethersulfone, polyphenylene sulfide, polyether ether ketone, polyether ketone, and polyoxybenzoic acid ester; metal oxide fillers such as silicon oxide, aluminum oxide, and yttrium oxide; metal carbides such as silicon carbide and aluminum carbide; metal nitride fillers such as silicon nitride and aluminum nitride; and inorganic fillers such as carbon black, aluminum fluoride, and fluorinated carbon.

[0157] Among these, from the perspective of the shielding effect of various plasmas, carbon black, alumina, silicon oxide, yttrium oxide, silicon carbide, silicon nitride, polyimide, and fluorocarbon are preferred.

[0158] In addition, the aforementioned inorganic and organic fillers can be mixed individually or in combination of two or more types.

[0159] In fields where high purity and non-polluting properties are not particularly required, common additives such as processing aids, plasticizers, and colorants that are to be mixed in the composition as needed can be added, or one or more commonly used crosslinking agents or crosslinking aids that are different from those mentioned above can be added.

[0160] The above composition may also contain an organic basic compound. Examples of organic basic compounds include:

[0161] Formula: CH3(CH2) 17 -NH2-octadecylamine;

[0162] Formula: H2N-C(O)-(CH2) 11 -CH=CH-(CH2)7CH3 erucamide;

[0163] Oleamide with the formula: H2N-C(O)-(CH2)7-CH=CH-(CH2)7CH3;

[0164] Formula: 1,6-hexanediamine of H2N-(CH2)6-NH2

[0165] Formula: [Chemistry 2] 1,8-diazabicycloundec-7-ene (DBU), etc.

[0166] (Cross-linking agents, etc.)

[0167] The compositions of the present invention may further contain at least one component selected from the group consisting of inorganic nitrides, organotin compounds, ammonia-generating compounds, and crosslinking agents. By including components such as crosslinking agents in the compositions of the present invention, crosslinked products can be readily obtained from the compositions of the present invention.

[0168] As inorganic nitrides, there are no particular limitations, and examples include silicon nitride (Si3N4), lithium nitride, titanium nitride, aluminum nitride, boron nitride, vanadium nitride, and zirconium nitride. Among these, silicon nitride is preferred from the perspective of its ability to supply nanoscale particles.

[0169] Examples of organotin compounds include tetraphenyltin and triphenyltin.

[0170] As a compound that generates ammonia, it is preferred to be a compound that generates ammonia at temperatures between 40°C and 330°C.

[0171] Urea or its derivatives, or ammonium salts, are preferred as ammonia-producing compounds; urea or ammonium salts are more preferred; and urea is even more preferred. The ammonium salt can be an organic or inorganic ammonium salt. Furthermore, any substance that reacts with trace amounts of water to produce ammonia can also be a ammonia-producing compound.

[0172] Examples of urea derivatives include diurea, thiourea, urea hydrochloride, and biuret.

[0173] Examples of organic ammonium salts include ammonium benzoate, ammonium adipate, and ammonium phthalate, which are non-fluorinated carboxylic acids or sulfonic acids.

[0174] Examples of inorganic ammonium salts include compounds described in Japanese Patent Application Publication No. 9-111081, such as ammonium sulfate, ammonium carbonate, ammonium nitrate, and ammonium phosphate.

[0175] In addition, examples of ammonia-producing compounds include acetaldehyde, hexamethylenetetramine, formamidine, formamidine hydrochloride, formamidine acetate, tert-butyl carbamate, benzyl carbamate, and phthalamide.

[0176] Examples of crosslinking agents include those used in peroxide crosslinking, polyol crosslinking, polyamine crosslinking, triazine crosslinking, oxazole crosslinking, imidazole crosslinking, and thiazole crosslinking. When the perfluoroelastomer has a cyano group (-CN group), at least one crosslinking agent preferably selected from the group consisting of oxazole crosslinking agents, imidazole crosslinking agents, and thiazole crosslinking agents is preferred.

[0177] The crosslinking agent used in peroxide crosslinking can be any organic peroxide that can readily generate peroxide free radicals in the presence of heat or a redox system. Specifically, examples include 1,1-bis(tert-butylperoxy)-3,5,5-trimethylcyclohexane, 2,5-dimethylhexane-2,5-dihydroperoxide, di-tert-butylperoxide (PerbutylD), tert-butylcumyl peroxide (PerbutylC), dicumyl peroxide (Percumyl D, Percumyl D-40, Percumyl D-40MB(T)), α,α-bis(tert-butylperoxy)-p-diisopropylbenzene, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane (Perhexa 25B, Perhexa 25B-40), and 2,5-dimethyl-2,5-di(tert-butylperoxy)-3-hexyne (Perhexyne 25B, Perhexyne...). 25B-40), benzoyl peroxide, tert-butyl peroxide, 2,5-dimethyl-2,5-di(benzoyl peroxide)hexane (Perhexa 25Z), tert-butyl maleate peroxide (t-butyl MA), tert-butyl isopropyl carbonate peroxide (Perbutyl I-75), methyl ethyl ketone peroxide (Permek D(DR), Permek H(HR, HY), Permek N(NR, NY), Permek S(SR), Permek F(FR), Permek G(GR, GY)), cyclohexanone peroxide (Perhexa H), acetylacetone peroxide (Percure AH, AL), 1,1-di(tert-hexylperoxy)-3,3,5-trimethylcyclohexane (Perhexa TMH), 1,1-di(tert-hexylperoxy)cyclohexane (Perhexa HC), 1,1-di(tert-butylperoxy)-2-methylcyclohexane (Perhexa MC), 1,1-di(tert-butylperoxy)cyclohexane (Perhexa C-80(S), Perhexa C-75(EB), Perhexa C(C), Perhexa C-40, Perhexa C-40MB(S)), 2,2-di(tert-butylperoxy)butane (Perhexa 22), 4,4-di(tert-butylperoxy)valerate (Perhexa V, Perhexa V-40(F)), 2,2-di(4,4-di(tert-butylperoxy)cyclohexyl)propane (Pertetra A), terpene hydroperoxide (Permenta H), dicumyl hydroperoxide (Percumyl P), 1,1,3,3-Tetramethylbutyl hydroperoxide (Perocta H), cumene hydroperoxide (Percumyl H-80), tert-butyl hydroperoxide (Perbutyl H-69), di(2-tert-butylisopropyl peroxide)benzene (Perbutyl P, Perbutyl P-40, Peroximon F-40, Perbutyl P-40MB(K)), ditert-hexyl peroxide (Perhexyl D), diisobutyryl peroxide (Peroyl IB), di(3,5,5-trimethylhexanoyl) peroxide (Peroyl 355(S)), dilauryl peroxide (Peroyl L), succinyl peroxide (Peroyl SA), di(3-methylbenzoyl) peroxide, benzoyl (3-methylbenzoyl) peroxide, and mixtures of benzoyl peroxide (NYPER BMT-K40, NYPER BMT-M), benzoyl peroxide (NYPER BW, NYPER BO, NYPER FF, NYPER BS, NYPER E, NYPER NS), bis(4-methylbenzoyl) peroxide (NYPER PMB), di-n-propyl peroxide (Peroyl NPP-50M), diisopropyl peroxide (Peroyl IPP-50, Peroyl IPP-27), di(4-tert-butylcyclohexyl) peroxide (Peroyl TCP), di(2-ethylhexyl) peroxide (Peroyl OPP), di-sec-butyl peroxide (Peroyl SBP), cumyl peroxide neodecanoate (Percumyl ND, Percumyl ND-50E), 1,1,3,3-tetramethylbutyl peroxide neodecanoate (Perocta ND, Perocta ND-50E), tert-hexyl peroxide neodecanoate (Perhexyl ND, Perhexyl ND-50E), tert-butyl peroxide neodecanoate (Perbutyl ND, Perbutyl ND-50E), tert-butyl peroxyn-2-hydroxyl peroxide (Perbutyl NHP), tert-hexyl peroxyn-2-hydroxyl peroxide (Perhexyl PV, Perhexyl PV-50E), tert-butyl peroxyn-2-hydroxyl peroxide (PerbutylPV, Perbutyl PV-40E), 1,1,3,3-tetramethylbutyl peroxide-2-ethylhexanoate (Perocta O), 2,5-dimethyl-2,5-Di(2-ethylhexanoyl)peroxyhexane (Perhexa 25O), tert-hexyl peroxy(2-ethylhexanoate) (PerhexylO, Percure HO(N)), tert-butyl peroxy(2-ethylhexanoate) (Perbutyl O, Percure O), tert-hexyl peroxyisopropyl monocarbonate (Perhexyl I), tert-butyl peroxy-3,5,5-trimethylhexanoate (Perbutyl355), tert-butyl peroxylaurate (Perbutyl L), tert-butyl peroxy-2-ethylhexyl monocarbonate (Perbutyl E), tert-hexyl peroxybenzoate (Perhexyl Z), tert-butyl peroxyacetate (Perbutyl A), a mixture of tert-butyl peroxy-3-methylbenzoate and tert-butyl peroxybenzoate (Perbutyl ZT), tert-butyl peroxybenzoate (Perbutyl Z), tert-butyl peroxyallyl monocarbonate (Peromer) Organic peroxides such as AC, 3,3',4,4'-tetra(tert-butylperoxycarbonyl)benzophenone (BTTB-25), and 2,3-dimethyl-2,3-diphenylbutane (NOFMER BC-90) are preferred. Dialkyl-type substances are preferred. Furthermore, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane is particularly preferred. The type and amount of organic peroxide are typically selected considering factors such as the amount of active -OO- and decomposition temperature.

[0178] Furthermore, any compound that is reactive against peroxide free radicals and polymer free radicals can be used as a crosslinking aid at this time. Examples include multifunctional compounds with functional groups such as -CH=CH2, -CH2CH=CH2, -CF=CF2, -C(CF3)=CF2, -C(CH3)=CF2, -CF=CF(CF3), -CF=CF(CH3), -C(C6H5)=CF2, -CF=CF(C6H5), -CH=CF2, -CF=CHF, -C(CF3)=CHF, -CF=CH(CF3), and -CH=CF(CF3) (in each formula, "C6H5" represents phenyl). Specifically, examples include triallyl cyanurate, triallyl isocyanurate (TAIC), 1,3,5-triacryloylhexahydro-1,3,5-triazine, triallyl trimellitate, N,N'-n-phenylene bismaleimide, diacetylacetate terephthalate, diallyl phthalate, tetraallyl terephthalamide, triallyl phosphate, bismaleimide, fluorinated triallyl isocyanurate (1,3,5-tris(2,3,3-trifluoro-2-propenyl)-1,3,5-triazine-2,4,6-trione), tris(diallylamine)-triazine, triallyl phosphite, N,N-diallylacrylamide, and 1,6-divinyldodecylfluorohexane.

[0179] In addition, as a crosslinking aid used with peroxide crosslinking agents, general formula (31) can also be cited:

[0180] [Chemistry 3]

[0181]

[0182] (In the formula, there are 6 R's) 31 Each is independently H, a halogen atom, or an optional halogenated group having 1 to 5 carbon atoms that may be inserted with an ether bond; Z 31 It is a compound, optionally containing heteroatoms, of linear or branched form with 1 to 18 carbon atoms, and optionally halogenated alkylene, cycloalkylene, or (per)fluoropolyalkylene oxide.

[0183] Examples of compounds represented by general formula (31) include compounds represented by general formula (32), compounds represented by general formula (33), compounds represented by general formula (34), etc.

[0184] General formula (32):

[0185] [Chemistry 4]

[0186]

[0187] (In the formula, j is an integer from 2 to 10, preferably an integer from 4 to 8, and 4 R...) 32 Each is independently H, F, or an alkyl or (per)fluoroalkyl group having 1 to 5 carbon atoms.

[0188] General formula (33):

[0189] [Chemistry 5]

[0190]

[0191] (where Y) 31 Each is independently F, Cl, or H, Y 32 Each independently can be F, Cl, H, or OR. 33 (Here, R) 33 (These are branched or straight-chain alkyl groups that can be substantially or completely fluorinated or chlorinated), Z 33 It can be an optional fluorinated divalent group with 2 to 10 carbon atoms that can be inserted with an ether bond, preferably Z. 33 -(CF2) is an integer where m is between 3 and 5. m -Base, the compound represented by general formula (33) is preferably F2C=CF-O-(CF2)5-O-CF=CF2)

[0192] General formula (34):

[0193] [Chemistry 6]

[0194]

[0195] (where Y) 31 Y 32 and Z 33 As mentioned above, R 34 Each is independently H, F, or an alkyl or (per)fluoroalkyl group having 1 to 5 carbon atoms.

[0196] Examples of crosslinking aids used in conjunction with crosslinking agents or peroxide crosslinking agents include those having at least one general formula (35):

[0197] [Chemistry 7]

[0198]

[0199] (where R is in the formula) 35 ~R 37 Each is independently a hydrogen atom, a fluorine atom, an alkyl group, a fluoroalkyl group, or a substituted or unsubstituted aryl group, R 35 ~R 37 At least one of them is a fluorine atom or a group containing a fluorine atom. m is an integer from 1 to 5. When m is 2 or more, there are m R atoms. 35 ~R 37 These can be the same or different. Compounds with the structure shown (with or without substituents on the hydrogen atoms of the benzene ring). When m is 1, it is preferable to have two or more of these structures.

[0200] Examples of compounds having the structure shown in general formula (36) include compounds shown in general formula (36), compounds shown in general formula (37), etc.

[0201] General formula (36):

[0202] [Chemistry 8]

[0203]

[0204] (where R is in the formula) 35 ~R 37 As mentioned above. (p is an integer from 0 to 2, and n is an integer from 2 to 6)

[0205] General formula (37):

[0206] [Chemistry 9]

[0207]

[0208] (where R is in the formula) 35 ~R 37 As described above. R38 It can be a single bond, -SO2-, -O-, -S-, -CO-, a heteroatom-containing group, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, or a substituted or unsubstituted arylene group. m is an integer from 1 to 5. (These groups may be partially or completely fluorinated.)

[0209] As a group containing heteroatoms, there are no particular limitations as long as it is a divalent group containing heteroatoms. Examples of heteroatoms include oxygen, nitrogen, sulfur, boron, and phosphorus atoms.

[0210] Examples of crosslinking agents used in polyol crosslinking include bisphenol A and bisphenol AF.

[0211] Examples of crosslinking agents used in polyamine crosslinking include 1,6-hexanediamine carbamate, N,N'-dicinnamyl-1,6-hexanediamine, and 4,4'-bis(aminocyclohexyl)methane carbamate.

[0212] Examples of crosslinking agents used in oxazole crosslinking, imidazole crosslinking, and thiazole crosslinking include, for example, the bis(diaminophenyl) crosslinking agent shown in general formula (41), the diaminophenol crosslinking agent, the bis(aminophenylthiophenol) crosslinking agent, the bis(aminohydrazone) crosslinking agent shown in general formula (42), the aminohydrazone crosslinking agent shown in general formula (43), or the bis(amide oxime) crosslinking agent shown in general formula (44), and the compound shown in general formula (45).

[0213] General formula (41):

[0214] [Chemistry 10]

[0215]

[0216] (where R is in the formula) 41 It is -SO2-, -O-, -CO-, alkylene groups with 1 to 6 carbon atoms, perfluoroalkylene groups with 1 to 10 carbon atoms, or a single bond, or

[0217] [Chemistry 11]

[0218]

[0219] The group shown, R 42 and R 43 One is -NH2 and the other is -NHR 44 -NH2, -OH or -SH, R 44 It is a hydrogen atom, a fluorine atom, or a monovalent organic group, preferably R. 42 -NH2, R 43 -NHR 44Preferred examples of alkylene groups having 1 to 6 carbon atoms include methylene, ethylene, propylene, butylene, pentylene, and hexylene. Examples of perfluoroalkylene groups having 1 to 10 carbon atoms include...

[0220] [Chemistry 12]

[0221]

[0222] (It should be noted that these compounds are known as examples of bis(diaminophenyl) compounds in Japanese Patent Application Publication No. 2-59177, Japanese Patent Application Publication No. 8-120146, etc.)

[0223] General formula (42):

[0224] [Chemistry 13]

[0225]

[0226] (R 41 As mentioned above, R 45 Each of the following groups can be independently identified as one of them.

[0227] [Chemistry 14]

[0228]

[0229] General formula (43):

[0230] [Chemistry 15]

[0231]

[0232] (where Rf) 41 It is a perfluoroalkylene group with 1 to 10 carbon atoms.

[0233] General formula (44):

[0234] [Chemistry 16]

[0235]

[0236] (In the formula, n is an integer from 1 to 10)

[0237] General formula (45): HN = CR 45 R 46

[0238] (where R is in the formula) 45 Choose freely from H, NH2 and NHR 47 In the group formed, R 46 Choose freely Ph, SO2H, NR 48 R 49In the group consisting of 2-pyridine and CH2CONH2, R 47 R is selected from the group consisting of Ph, NH2, and CN. 48 Selected from the group consisting of H, NHPh, CH2CONH2, straight-chain alkyl groups with 1 to 8 carbon atoms, and branched-chain alkyl groups with 1 to 8 carbon atoms, and R 49 Choose from Ph, COOC(CH3)3, NH2, CH2COOH, CSNH2, and CNHNH3. + Cl - p-Phenyl CN,

[0239] [Chemistry 17]

[0240]

[0241] (in the group composed of COPh)

[0242] These diaminophenol-based crosslinking agents, diaminobenzylthiophenol-based crosslinking agents, or diaminophenyl-based crosslinking agents have previously been used in crosslinking systems with cyano groups as crosslinking points. However, they react with both carboxyl and alkoxycarbonyl groups to form oxazole, thiazole, and imidazole rings, providing crosslinked products.

[0243] In addition, general formula (46) can also be cited as a crosslinking agent: X 41 -(CH2) n -R 50 -(CH2) m -X 41 (where X) 41 Each can be independently alkynyl, nitrile, or Y-. 41 P N3(Y 41 For SO, SO2, C6H4, or CO, p is 0 or 1), n ​​and m are independent integers from 1 to 4, R 50 Choose Freedom

[0244] i) Fluoroalkylene groups having 3 to 10 carbon atoms,

[0245] ii) Fluoroalkoxides with 3 to 10 carbon atoms,

[0246] iii) Replacing aryl groups,

[0247] iv) Oligomers containing copolymer units of vinylidene fluoride and perfluorinated (methyl vinyl ether),

[0248] v) Oligomers containing copolymer units of vinylidene fluoride and hexafluoropropylene,

[0249] vi) Oligomers containing copolymer units of tetrafluoroethylene and perfluoro(methyl vinyl ether) and

[0250] vii) The crosslinking agent shown in the group consisting of oligomers comprising copolymer units of tetrafluoroethylene and hydrocarbon olefins. This crosslinking agent is preferably used with a perfluoroelastomer having a nitrile, azide, sulfonyl azide, carbonyl azide, or alkynyl group. For example, the nitrile group of the perfluoroelastomer reacts with the azide group of the crosslinking agent to form a tetrazolium ring, providing the crosslinked product.

[0251] As particularly preferred crosslinking agents, examples include compounds having two or more 3-amino-4-hydroxyphenyl or 3-amino-4-mercaptophenyl groups, or those of general formula (47):

[0252] [Chemistry 18]

[0253]

[0254] (where R is in the formula) 41 R 42 and R 43 The compounds shown above, specifically, for example, are 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (common name: bis(aminophenol)AF), 2,2-bis(3-amino-4-mercaptophenyl)hexafluoropropane, tetraaminobenzene, bis-3,4-diaminophenylmethane, bis-3,4-diaminophenyl ether, 2,2-bis(3,4-diaminophenyl)hexafluoropropane, 2,2-bis[3-amino-4-(N-phenylamino)] [Phenylene]hexafluoropropane, 2,2-bis[3-amino-4-(N-methylamino)phenyl]hexafluoropropane, 2,2-bis[3-amino-4-(N-ethylamino)phenyl]hexafluoropropane, 2,2-bis[3-amino-4-(N-propylamino)phenyl]hexafluoropropane, 2,2-bis[3-amino-4-(N-perfluorophenylamino)phenyl]hexafluoropropane, 2,2-bis[3-amino-4-(N-benzylamino)phenyl]hexafluoropropane, etc.

[0255] Among these, 2,2-bis[3-amino-4-(N-phenylamino)phenyl]hexafluoropropane is preferred as a crosslinking agent in terms of heat resistance, steam resistance, amine resistance, and good crosslinking properties.

[0256] The content of at least one of the following, selected from the group consisting of inorganic nitrides, organotin compounds, ammonia-generating compounds and crosslinking agents, is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, even more preferably 0.2 parts by mass or more, particularly preferably 0.3 parts by mass or more, preferably 10 parts by mass or less, more preferably 5.0 parts by mass or less, even more preferably 2.0 parts by mass or less, and particularly preferably 1.0 parts by mass or less.

[0257] (Cross-linked compound)

[0258] The above composition is suitable for use as a molding material for crosslinking to obtain crosslinked products. Crosslinked products can be obtained by crosslinking the composition of the present invention. The crosslinked products of the present invention exhibit excellent durability against NF3 plasma and show little compression set even when used at high temperatures exceeding 300°C.

[0259] The compression set (300°C) of the crosslinked material of the present invention, measured by placing it at 300°C for 70 hours with a compression ratio of 25%, is preferably 60% or less, more preferably 55% or less. The compression set (300°C) can be calculated by measuring the thickness of the crosslinked material before and after compression, after placing it at 300°C for 70 hours with the crosslinked material compressed at a compression ratio of 25%, releasing the compression, and placing it at 23°C for 30 minutes.

[0260] The crosslinked material of the present invention is not easily crushed even when compressed at high temperatures. According to the present invention, a crosslinked material is provided that will not break even after being placed at 300°C for 70 hours with a compression ratio of 25%. Furthermore, according to the present invention, a crosslinked material is provided that will not break even in the above-mentioned test for measuring compression set (300°C) and that allows for the measurement of compression set (300°C) (i.e., a crosslinked material having a value for compression set (300°C)).

[0261] The compression set of the crosslinked material of the present invention, measured by placing it at 200°C for 70 hours with a compression ratio of 25% and then at 70°C for 24 hours, is preferably 70% or less, more preferably 65% ​​or less. The compression set (temperature change from 200°C to 70°C) can be calculated as follows: after compressing the crosslinked material at a compression ratio of 25%, placing it at 200°C for 70 hours and then at 70°C for 24 hours, releasing the compression, and placing it at 23°C for 30 minutes, the thickness of the crosslinked material before and after compression is measured.

[0262] One method for obtaining a cross-linked product from the composition is to obtain a preform by molding the composition as a molding material and then cross-linking the preform. The method for obtaining a preform from the composition can be a conventional method, such as heating and compressing with a mold, pressing into a heated mold, or extruding with an extruder. In the case of extruded products such as hoses or wires, a cross-linked product can be obtained by heating and cross-linking based on steam or the like after extrusion.

[0263] The aforementioned crosslinking is referred to as primary crosslinking, and can be carried out in the order of primary crosslinking and secondary crosslinking. Primary crosslinking is preferably carried out at 150°C to 250°C for 5 to 120 minutes, and more preferably at 170°C to 200°C for 5 to 60 minutes. As the crosslinking method, any known crosslinking method can be used, such as pressure crosslinking.

[0264] The secondary crosslinking is preferably performed at 250°C to 320°C for 2 to 48 hours, more preferably at 280°C to 310°C for 5 to 24 hours. Alternatively, the secondary crosslinking can be performed at 180°C to 320°C for 2 to 24 hours, or at 190°C to 310°C for 5 to 20 hours. Temperature variations are also possible within this temperature range. Known crosslinking methods can be used as the crosslinking method, such as heat crosslinking. Crosslinking can be performed, for example, in an air atmosphere or a nitrogen atmosphere.

[0265] The crosslinked material of the present invention is suitable for use as a sealing material for semiconductor manufacturing apparatuses that require particularly high heat resistance, especially for semiconductor manufacturing apparatuses subjected to high-density plasma irradiation. Examples of such sealing materials include O-rings, square rings, gaskets, sealing pads, oil seals, bearing seals, and lip seals.

[0266] In addition, it can be used in various polymer products used in semiconductor manufacturing equipment, such as diaphragms, tubes, hoses, various rubber rollers, belts, etc. It can also be used as a coating material and a lining material.

[0267] It should be noted that the semiconductor manufacturing apparatus mentioned in this invention is not particularly limited to apparatus for manufacturing semiconductors, but broadly includes all manufacturing apparatuses used in the semiconductor field that require high cleanliness, such as apparatuses for manufacturing liquid crystal panels or plasma panels, for example the following apparatuses.

[0268] (1) Etching apparatus

[0269] Dry etching apparatus

[0270] Plasma etching device

[0271] Reactive ion etching device

[0272] Reactive ion beam etching apparatus

[0273] sputtering etching equipment

[0274] Ion beam etching equipment

[0275] wet etching apparatus

[0276] Ashing device

[0277] (2) Cleaning device

[0278] Dry etching cleaning equipment

[0279] UV / O3 cleaning device

[0280] Ion beam cleaning device

[0281] Laser beam cleaning device

[0282] Plasma cleaning device

[0283] Gas Etching Cleaning Equipment

[0284] Extraction and cleaning device

[0285] Soxhlet extraction and cleaning apparatus

[0286] High-temperature and high-pressure extraction and cleaning device

[0287] Microwave extraction and cleaning device

[0288] Supercritical extraction and cleaning device

[0289] (3) Exposure device

[0290] lithography machine

[0291] Coating machine and developing machine

[0292] (4) Grinding device

[0293] CMP device

[0294] (5) Film forming device

[0295] CVD device

[0296] Sputtering device

[0297] (6) Diffusion-ion implantation device

[0298] Oxidation diffusion device

[0299] Ion implantation device

[0300] The crosslinked material of the present invention can exhibit excellent performance as a sealing material for, for example, CVD equipment, plasma etching equipment, reactive ion etching equipment, ashing equipment or excimer laser exposure machine.

[0301] The embodiments described above are as follows, but it will be understood that various changes in manner and details may be made without departing from the spirit and scope of the claims.

[0302] <1> According to a first aspect of the present invention, a composition is provided comprising a perfluoroelastomer and polytetrafluoroethylene, wherein the melt viscosity of the polytetrafluoroethylene is 1.0 × 10⁻⁶. 3 Moor ~7.0×10 6The above-mentioned polytetrafluoroethylene has a melting point of 322°C or higher, and the above-mentioned composition is obtained by co-precipitation of the above-mentioned perfluoroelastomer and the above-mentioned polytetrafluoroethylene.

[0303] <2> According to a second aspect of the invention, a composition based on the first aspect is provided, wherein the perfluoroelastomer has a cyano group.

[0304] <3> According to a third aspect of the invention, a composition based on the first or second aspect is provided, wherein the polytetrafluoroethylene optionally contains modified monomer units, the content of which is 0 mol% to 0.10 mol% relative to all monomer units.

[0305] <4> According to a fourth aspect of the invention, a composition based on the first or second aspect is provided, wherein the polytetrafluoroethylene contains modified monomer units, the content of which is 0.02 mol% to 0.10 mol% relative to all monomer units.

[0306] <5> According to a fifth aspect of the invention, a composition based on the fourth aspect is provided, wherein the modified monomer unit is at least one selected from the group consisting of hexafluoropropylene units and perfluorovinyl ether units.

[0307] <6> According to a sixth aspect of the present invention, a composition based on any one of the first to fifth aspects is provided, wherein the average primary particle size of the polytetrafluoroethylene is 200 nm or more.

[0308] <7> According to a seventh aspect of the present invention, a composition based on any one of the first to sixth aspects is provided, wherein the content of the polytetrafluoroethylene is 1 to 100 parts by mass relative to 100 parts by mass of the perfluoroelastomer.

[0309] <8> According to an eighth aspect of the present invention, a composition based on any one of the first to seventh aspects is provided, wherein the composition is obtained by preparing an aqueous dispersion containing the above-mentioned perfluoroelastomer and the above-mentioned polytetrafluoroethylene and using an acid to co-precipitate the above-mentioned perfluoroelastomer and the above-mentioned polytetrafluoroethylene in the resulting aqueous dispersion.

[0310] <9> According to a ninth aspect of the present invention, a composition based on any one of the first to eighth aspects is provided, wherein the composition further comprises at least one selected from the group consisting of inorganic nitrides, organotin compounds, ammonia-generating compounds, and crosslinking agents.

[0311] <10> According to a tenth aspect of the present invention, a crosslinked material is provided, which is obtained by crosslinking a composition based on any one of the first to ninth aspects.

[0312] Example

[0313] Next, embodiments will be given to illustrate the implementation of the present invention, but the present invention is not limited to the embodiments described herein.

[0314] The values ​​in the examples were measured using the following methods.

[0315] (Composition of PTFE)

[0316] pass 19 Determined by F-NMR analysis.

[0317] (Average primary particle size of PTFE)

[0318] The average primary particle size was determined as follows: After determining the correlation between the transmittance of a specified unit containing an aqueous PTFE dispersion with a solid content adjusted to 0.15% by mass and the incident light at 550 nm, and the number-average primary particle size calculated by measuring the directional diameter using a transmission electron microscope, the transmittance of the obtained sample was substituted into the above correlation to obtain the primary particle size (standard curve method).

[0319] (The melting point of PTFE)

[0320] The melting point of PTFE was determined as follows: Using a Hitachi High-Tech Corporation X-DSC7000 (DSC) differential scanning calorimeter, approximately 3 mg of PTFE (after temperature calibration with indium and lead, and without being heated to a temperature above 300°C) was placed in an aluminum dish. Under a nitrogen flow of 40 ml / min, the temperature range of 230°C to 350°C was increased at a rate of 10°C / min, and differential scanning calorimetry was performed. The temperature corresponding to the minimum point of the melting curve in the above range was taken as the melting point.

[0321] (PTFE melt viscosity)

[0322] Melt viscosity was determined according to ASTM D 1238 using a flow tester (manufactured by Shimadzu Corporation). The die head was used to hold a 2g sample, preheated to 380°C for 5 minutes, at the aforementioned temperature under a load of 0.7MPa for measurement. "Insoluble" in the table means that the PTFE has not melted and its melt viscosity cannot be measured.

[0323] (Composition of perfluoroelastomers)

[0324] pass 19 Determined by F-NMR analysis.

[0325] Mooney viscosity of perfluoroelastomers

[0326] The measurements were performed at 170°C using a Mooney MV2000E viscometer manufactured by ALPHA TECHNOLOGIES, according to JISK 6300.

[0327] (Compression set (300℃))

[0328] Compression set was determined according to the methods described in ASTM D395 or JIS K6262. Using a compression apparatus, the O-rings produced in the examples and comparative examples were compressed at room temperature to a compression ratio of 25% (compressing an O-ring with a thickness (wire diameter) of 3.5 mm to a thickness of 2.625 mm).

[0329] Next, the compression device with the compressed O-ring fixed in place was placed in an electric furnace at 300°C for 70 hours, after which the compression device was removed from the furnace. The O-ring was removed from the compression device and placed in a constant temperature chamber at 23°C for 30 minutes, and the thickness (t2) of the O-ring was measured. The compression set was calculated using the following formula. Furthermore, the closer the compression set is to 0%, the better the compression set characteristics of the crosslinked material.

[0330] Compression set (%) = (t0-t2) / (t0-t1)×100

[0331] t0: Original thickness of the O-ring (mm)

[0332] t1: Thickness of the spacer (mm)

[0333] t2: Thickness of the O-ring after the compression test (mm)

[0334] In the above experiment, t0 = 3.5 mm and t1 = 2.625 mm.

[0335] (Crack rate (300℃))

[0336] For the 12 O-rings following the "compression set (300°C)" test, the crack initiation state was visually confirmed. The crack rate was calculated using the following formula. Furthermore, the closer the crack rate is to 0%, the less likely the cross-linked material is to crack even under compression.

[0337] Crack rate (%) = (Number of cracks) / (Number of tests) × 100

[0338] In the above experiment, the number of trials was 12.

[0339] (Compression set (temperature changed from 200℃ to 70℃))

[0340] Compression set was determined according to the methods described in ASTM D395 or JIS K6262. Using a compression apparatus, the O-rings produced in the examples and comparative examples were compressed at room temperature to a compression ratio of 25% (compressing an O-ring with a thickness (wire diameter) of 3.5 mm to a thickness of 2.625 mm).

[0341] Next, the compression device with the compressed O-ring fixed in place was placed in an electric furnace and kept at 200°C for 70 hours. Afterward, the compression device was removed from the furnace. Then, the compression device with the compressed O-ring fixed in place was placed in another electric furnace and kept at 70°C for 24 hours. The O-ring was removed from the compression device and placed in a constant temperature chamber at 23°C for 30 minutes. The thickness (t2) of the O-ring was measured. The permanent compression deformation was calculated using the following formula.

[0342] Compression set (%) = (t0-t2) / (t0-t1)×100

[0343] t0: Original thickness of the O-ring (mm)

[0344] t1: Thickness of the spacer (mm)

[0345] t2: Thickness of the O-ring after the compression test (mm)

[0346] In the above experiment, t0 = 3.5 mm and t1 = 2.625 mm.

[0347] (Crack rate (temperature changed from 200℃ to 70℃))

[0348] For the 12 O-rings following the "compression set (temperature changed from 200℃ to 70℃)" test, the crack initiation state was visually confirmed. The crack rate was calculated using the following formula. Furthermore, the closer the crack rate is to 0%, the less likely the cross-linked material is to crack even under compression.

[0349] Crack rate (%) = (Number of cracks) / (Number of tests) × 100

[0350] In the above experiment, the number of trials was 12.

[0351] (Plasma resistance (weight reduction rate of crosslinked material before and after plasma treatment))

[0352] The O-rings (P24 size) fabricated in the examples and comparative examples were placed in the process chamber. Plasma generated using a free radical generation device was introduced into the processing chamber, exposing the O-rings under the following plasma irradiation conditions. The NF3 remote plasma weight reduction rate was calculated based on the mass of the O-rings before and after plasma irradiation.

[0353] (Plasma irradiation conditions)

[0354] Fluorine radical generation device: Astron Atomic Fluorine Generator Model AX7657-2 (manufactured by MKS Company)

[0355] Gas flow rate: Ar / NF3 = 1 (L / min) / 1 (L / min)

[0356] Stress: 3 Torr

[0357] Irradiation temperature: 250℃

[0358] Irradiation time: 12 hours (the position of the O-ring in the chamber is moved every 2 hours).

[0359] The following materials are used in the embodiments and comparative examples.

[0360] Perfluoroelastomers:

[0361] TFE / PMVE / CF2=CFOCF2CF(CF3)OCF2CF2CN=59.3 / 39.9 / 0.8 ​​(mol%)

[0362] Mooney viscosity ML(1+20) (170℃) = 66

[0363] Crosslinking agent:

[0364] 2,2-Bis[3-amino-4-(N-phenylamino)phenyl]hexafluoropropane

[0365] PTFE:

[0366] PTFE with the properties described in Table 1

[0367] Example 1

[0368] 880 g of an emulsion of perfluoroelastomer particles (solid content concentration 24 wt%) and 282 g of an emulsion of PTFE particles having the properties described in Table 1 (solid content concentration 15 wt%) were mixed at 23°C and co-precipitated by dropwise addition to 500 g of 10% nitric acid at 23°C over 10 minutes. The resulting coprecipitate was washed with water and dried at 70°C using a vacuum dryer to obtain an elastomer composition in which PTFE is micro-dispersed in a fluorinated elastomer.

[0369] Differential thermal analysis (DTA) was used to determine the elastomer composition, and the results at 327.7°C confirmed an absorption that was believed to be based on PTFE.

[0370] In 120 parts by weight of the obtained elastomer composition, 0.9 parts by weight of crosslinking agent (2,2-bis[3-amino-4-(N-phenylamino)phenyl]hexafluoropropane) were mixed and kneaded using a two-roll mill to obtain a crosslinked elastomer composition.

[0371] Subsequently, the crosslinked elastomer composition was crosslinked under pressure at 180°C for 30 minutes, followed by thermal crosslinking at 290°C for 18 hours to produce P24-sized O-rings. Using the obtained O-rings, compression set (300°C), compression set (temperature changed from 200°C to 70°C), and NF3 remote plasma reduction rate were measured using the above method. The results are shown in Table 1.

[0372] Examples 2 to 3

[0373] Elastomer compositions and crosslinked elastomer compositions, as well as O-rings, were obtained in the same manner as in Example 1. The DTA determination results for the elastomer compositions showed that absorption believed to be PTFE-based was confirmed at 327.5°C in Example 2 and at 329.5°C in Example 3.

[0374] Comparative Example 1

[0375] The emulsion of perfluoroelastomer particles used in Example 1 at 23°C was added dropwise to 10% nitric acid at 23°C to precipitate them. After washing the precipitate, it was dried to obtain perfluoroelastomer particles. On the other hand, nitric acid was added to the emulsion of PTFE particles used in Example 1 to precipitate them. The precipitate was washed and dried to obtain white PTFE powder.

[0376] 100 parts by weight of perfluorinated elastomer particles, 20 parts by weight of PTFE powder, and 0.9 parts by weight of crosslinking agent (2,2-bis[3-amino-4-(N-phenylamino)phenyl]hexafluoropropane) were mixed in an open mill to obtain a crosslinked elastomer composition.

[0377] O-rings were fabricated in the same manner as in Examples 1 to 3. Compression set (300°C), compression set (temperature changed from 200°C to 70°C), and NF3 remote plasma weight reduction rate were measured using the above method. The results are shown in Table 1.

[0378] Comparative Example 2

[0379] Except for the PTFE described in Table 1, O-rings were fabricated in the same manner as in Examples 1 to 3, and the obtained O-rings were evaluated in the same way. The results are shown in Table 1.

[0380] [Table 1]

[0381] Table 1

[0382]

[0383] Examples 4 to 7

[0384] The amounts of each material were varied in the manner described in Table 2, and otherwise, the elastomer composition, the crosslinked elastomer composition, and the O-ring were obtained in the same manner as in Example 1. The results are shown together with the results of Example 1 in Table 2.

[0385] Comparative Example 3

[0386] In Comparative Example 1, 0.9 parts by mass of a crosslinking agent (2,2-bis[3-amino-4-(N-phenylamino)phenyl]hexafluoropropane) were mixed with 100 parts by mass of perfluorinated elastomer particles using a two-roll mill to obtain a crosslinked elastomer composition. O-rings were prepared from the crosslinked elastomer composition in the same manner as in Example 1, and the resulting O-rings were evaluated in the same way. The results are shown in Table 2.

[0387] [Table 2]

[0388] Table 2

[0389]

Claims

1. A composition which is a composition containing a perfluoroelastomer and polytetrafluoroethylene, wherein The melt viscosity of the polytetrafluoroethylene is 1.0 x 10 3 Poise - 7.0 x 10 6 Poise, the polytetrafluoroethylene has a melting point of 322°C or higher, the composition is obtained by co-coagulating the perfluoroelastomer and the polytetrafluoroethylene in an aqueous dispersion containing the perfluoroelastomer and the polytetrafluoroethylene, which is prepared by a first method of mixing an aqueous dispersion containing the perfluoroelastomer with an aqueous dispersion containing the polytetrafluoroethylene, or a second method of mixing a powder of the perfluoroelastomer with an aqueous dispersion containing the polytetrafluoroethylene, from the aqueous dispersion prepared by the first method or the second method, thereby obtaining the composition.

2. The composition of claim 1, wherein, the perfluoroelastomer has a cyano group.

3. The composition of claim 1 or 2, wherein, the polytetrafluoroethylene optionally contains a modified monomer unit, the content of which is 0 to 0.10 mol% relative to the total monomer units.

4. The composition of claim 1 or 2, wherein, the polytetrafluoroethylene contains a modified monomer unit, the content of which is 0.02 to 0.10 mol% relative to the total monomer units.

5. The composition of claim 4, wherein, the modified monomer unit is at least one selected from the group consisting of hexafluoropropene units and perfluorovinyl ether units.

6. The composition of claim 1 or 2, wherein, the average primary particle diameter of the polytetrafluoroethylene is 200 nm or more.

7. The composition of claim 1 or 2, wherein, the content of the polytetrafluoroethylene is 1 to 100 parts by mass relative to 100 parts by mass of the perfluoroelastomer.

8. The composition according to claim 1 or 2, which is obtained by co-coagulating the perfluoroelastomer and the polytetrafluoroethylene in the aqueous dispersion prepared by the first method or the second method using an acid.

9. The composition according to claim 1 or 2, which further contains at least one selected from the group consisting of inorganic nitrides, organotin compounds, ammonia-generating compounds and crosslinking agents.

10. A crosslinked product which is obtained by crosslinking the composition according to claim 1 or 2.

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