Fluororubber composition and molded article

Abstract

Provided is a fluororubber composition comprising a fluororubber (a), a crosslinking agent (b), and an organic acid (c), wherein the organic acid (c) comprises at least one organic acid selected from the group consisting of C3-10 organic acids each having one acid group in the molecule and C2-10 organic acids each having two or more acid groups in the molecule.

Description

Fluororubber composition and molded article

[0001] The present disclosure relates to a fluororubber composition and a molded article.

[0002] Patent Document 1 describes a composition for producing a cured elastomer, which comprises an elastomeric copolymer, a triorganosulfonium compound, and an aromatic polyhydroxy compound.

[0003] Special Publication No. 64-418

[0004] An object of the present disclosure is to provide a fluororubber composition which, like conventional fluororubber compositions, can be crosslinked to give a fluororubber molded article having excellent properties, and which has a long crosslinking induction time (T10) upon crosslinking.

[0005] According to the present disclosure, there is provided a fluororubber composition comprising a fluororubber (a), a crosslinking agent (b), and an organic acid (c), wherein the organic acid (c) is at least one selected from the group consisting of organic acids having 3 to 10 carbon atoms and having one acid group in the molecule, and organic acids having 2 to 10 carbon atoms and having two or more acid groups in the molecule.

[0006] According to the present disclosure, a fluororubber composition can be provided which can obtain a fluororubber molded article having excellent properties by crosslinking, similar to conventional fluororubber compositions, and which has a long crosslinking induction time (T10) upon crosslinking.

[0007] Specific embodiments of the present disclosure will be described in detail below, but the present disclosure is not limited to the following embodiments.

[0008] <Fluororubber Composition> The fluororubber composition of the present disclosure contains a fluororubber (a), a crosslinking agent (b), and an organic acid (c).

[0009] Conventionally, as a fluororubber composition that can be crosslinked to give a fluororubber molded article, there has been known a fluororubber composition containing an elastomeric copolymer and a bisphenol compound, hexafluoroisopropylidene-bis(4-hydroxybenzene), known as bisphenol AF, as described in Patent Document 1.

[0010] Such conventional fluororubber compositions have a relatively short crosslinking induction time (T10), and the crosslinking reaction may proceed before the fluororubber composition is sufficiently filled into a mold for molding, resulting in molding defects. Furthermore, when such conventional fluororubber compositions are stored for a long period of time, the crosslinking reaction may proceed gradually. Therefore, when a fluororubber composition that has been stored for a long period of time is molded and crosslinked to produce a fluororubber molded product, molding defects may occur.

[0011] Since the fluororubber composition of the present disclosure contains an organic acid (c), the crosslinking induction time (T10) during crosslinking is longer than that of a conventional fluororubber composition containing the same components except for not containing the organic acid (c). Therefore, when the fluororubber composition of the present disclosure is filled into a mold for molding, the time required for the fluororubber composition to sufficiently fill the mold can be ensured, making molding defects less likely to occur. Furthermore, even when the fluororubber composition of the present disclosure is stored for a long period of time, the crosslinking reaction does not progress easily, so even when a fluororubber molded article is produced by molding and crosslinking a fluororubber composition that has been stored for a long period of time, molding defects are less likely to occur. Moreover, the resulting fluororubber molded article exhibits excellent properties, similar to those of fluororubber molded articles obtained from conventional fluororubber compositions.

[0012] Each component of the fluororubber composition of the present disclosure will be described below.

[0013] (a) Fluororubber The fluororubber composition of the present disclosure contains a fluororubber. In the present disclosure, the fluororubber is an amorphous fluoropolymer. "Amorphous" means that the magnitude of the melting peak (ΔH) appearing in differential scanning calorimetry (DSC) (heating rate 20°C / min) or differential thermal analysis (DTA) (heating rate 20°C / min) of the fluoropolymer is 4.5 J / g or less. Fluororubber exhibits elastomeric properties by crosslinking. Elastomeric properties refer to the ability of a polymer to be stretched and to retain its original length when the force required to stretch the polymer is no longer applied.

[0014] Generally, rubber and elastomers refer to substances whose "glass transition temperature (Tg)" in DSC measurement is below room temperature and which are usually in an amorphous state at room temperature. Conversely, substances whose Tg is above room temperature are in a frozen state at room temperature, and substances with such properties are called resins.

[0015] The fluororubber is preferably a fluororubber containing vinylidene fluoride units, which can be crosslinked with a polyol. The fluororubber containing vinylidene fluoride units may be, for example, a vinylidene fluoride (VdF)-based fluoroelastomer substantially free of polar end groups, as described in JP 2003-277563 A; a vinylidene fluoride-based fluoroelastomer containing repeating units derived from vinylidene fluoride (VdF) and repeating units derived from at least one additional (per)fluorinated monomer, as described in JP 2018-527449 A; or a cured fluoroelastomer having a small amount of fluorine of less than 67% by weight, as described in JP 7-316377 A, which contains 40 to 68% by weight of vinylidene fluoride (VdF) units and 20 to 50% by weight of hexafluoropropylene (HFP) units so that the total amount is 100, and optionally contains one or more comonomers having ethylene unsaturation.

[0016] Examples of fluororubbers containing vinylidene fluoride units (VdF-based fluororubbers) include tetrafluoroethylene (TFE) / propylene / VdF-based fluororubbers, ethylene / hexafluoropropylene (HFP) / VdF-based fluororubbers, VdF / HFP-based fluororubbers, VdF / TFE / HFP-based fluororubbers, etc. These fluororubbers can be used alone or in any combination within the scope that does not impair the effects of the present disclosure.

[0017] The VdF-based fluororubber is preferably one represented by the following general formula (1).

[0018] - (M １ )-(M ２ )-(N １ ) - (1) (wherein the structural unit M１ is vinylidene fluoride (m １ ) is a structural unit derived from the structural unit M ２ is a fluorine-containing ethylenic monomer (m ２ ) is a structural unit derived from the structural unit N １ is the monomer (m １ ) and monomer (m ２ ) and a copolymerizable monomer (n １ ) is a repeating unit derived from

[0019] Among the VdF-based fluororubbers represented by the general formula (1), the structural unit M １ 30 to 85 mol % of the structural unit M ２ Preferably, the structural unit M １ 50 to 80 mol % of the structural unit M ２ The structural unit N is 50 to 20 mol %. １ is the structural unit M １ and structural unit M ２ It is preferably 0 to 20 mol % based on the total amount of the above.

[0020] Fluorine-containing ethylenic monomer (m ２ As the alkyl ether (A), one or more monomers can be used, and examples thereof include TFE, chlorotrifluoroethylene (CTFE), trifluoroethylene, HFP, trifluoropropylene, tetrafluoropropylene, pentafluoropropylene, trifluorobutene, tetrafluoroisobutene, perfluoro(alkyl vinyl ether) (PAVE), alkyl ethers of the general formula (2): CF ２ = CFO(Rf １ O) ｑ (Rf ２ O) ｒ Rf ３ (2) (wherein, Rf １ and Rf ２ each independently represents a linear or branched perfluoroalkylene group having 1 to 6 carbon atoms; Rf ３ is a linear or branched perfluoroalkyl group having 1 to 6 carbon atoms, and q and r each independently represent an integer of 0 to 6 (provided that 0<q+r≦6 is satisfied); a fluorine-containing monomer represented by the general formula (3): CHX １１ =CX１２ Rf ４ (3) (wherein, X １１ and X １２ is H on one side and F on the other side, and Rf ４ represents a linear or branched fluoroalkyl group having 1 to 12 carbon atoms), and vinyl fluoride. Among these, TFE, HFP, and PAVE are preferred.

[0021] Monomer (n １ ) as a monomer (m １ ) and monomer (m ２ Any copolymerizable copolymer may be used, including, for example, ethylene, propylene, alkyl vinyl ether, a monomer that provides a crosslinking site, a bisolefin compound, etc. These may be used alone or in any combination.

[0022] Examples of the monomer that provides such a crosslinking site include a monomer represented by the general formula (4): CY １ ２ =CY １ -Rf ５ CHR １ X １ (4) (wherein, Y １ are independently a hydrogen atom, a fluorine atom, or —CH ３ , Rf ５ represents a fluoroalkylene group, a perfluoroalkylene group, a fluoropolyoxyalkylene group or a perfluoropolyoxyalkylene group, R １ is a hydrogen atom or -CH ３ , X １ represents an iodine atom or a bromine atom), an iodine- or bromine-containing monomer represented by the general formula (5): CF ２ = CFO (CF ２ CF (CF ３ ) O) ｍ (CF ２ ) ｎ -X ２ (5) (wherein m is an integer of 0 to 5, n is an integer of 1 to 3, X ２is a cyano group, a carboxyl group, an alkoxycarbonyl group, a bromine atom, or an iodine atom), a monomer represented by the general formula (6): CH ２ =CH(CF ２ ) ｐ I (6) (wherein p is an integer of 1 to 10), and the like, for example, iodine-containing monomers such as perfluoro(6,6-dihydro-6-iodo-3-oxa-1-hexene) and perfluoro(5-iodo-3-oxa-1-pentene) as described in JP-B-5-63482 and JP-A-7-316234, and CF ２ = CFOCF ２ CF ２ CH ２ Examples of suitable iodine-containing monomers include iodine-containing monomers such as iodine-containing monomers I, iodine-containing monomers such as 4-iodo-3,3,4,4-tetrafluoro-1-butene described in JP-A-61-55138, bromine-containing monomers described in JP-A-4-505341, and cyano group-containing monomers, carboxyl group-containing monomers, and alkoxycarbonyl group-containing monomers described in JP-A-4-505345 and JP-A-5-500070. These may be used alone or in any combination. Furthermore, bisolefin compounds such as those described in JP-A-8-12726 may be used.

[0023] Specific preferred examples of the VdF-based fluororubber include VdF / HFP-based rubber, VdF / HFP / TFE-based rubber, VdF / TFE / PAVE-based fluororubber, VdF / CTFE-based rubber, and VdF / CTFE / TFE-based rubber.

[0024] Among these, the fluororubber is preferably a fluororubber composed of VdF and at least one other fluorine-containing monomer, and particularly preferably at least one rubber selected from the group consisting of VdF / HFP-based fluororubbers, VdF / TFE / HFP-based fluororubbers, and VdF / TFE / PAVE-based fluororubbers, and more preferably at least one rubber selected from the group consisting of VdF / HFP-based fluororubbers and VdF / TFE / HFP-based fluororubbers.

[0025] The fluororubber preferably has a Mooney viscosity at 121°C (ML1+10(121°C)) of 1 or more, more preferably 3 or more, even more preferably 5 or more, and particularly preferably 10 or more. The Mooney viscosity is preferably 200 or less, more preferably 170 or less, even more preferably 150 or less, even more preferably 130 or less, and particularly preferably 100 or less. The Mooney viscosity is measured in accordance with ASTM D1646-15 and JIS K6300-1:2013.

[0026] The fluorine content of the fluororubber is preferably 50 to 75% by mass, more preferably 60 to 73% by mass, and even more preferably 63 to 72% by mass. The fluorine content can be calculated from the composition ratio of the monomer units constituting the fluororubber.

[0027] The fluororubber preferably has a glass transition temperature of −50 to 0° C. The glass transition temperature can be determined by obtaining a DSC curve using a differential scanning calorimeter by heating 10 mg of a sample at a rate of 20° C. / min, and determining the glass transition temperature as the temperature at the intersection between an extension of the baseline before and after the second-order transition of the DSC curve and a tangent to the inflection point of the DSC curve.

[0028] The fluororubber described above can be produced by a conventional method.

[0029] (b) Crosslinking Agent The fluororubber composition of the present disclosure contains a crosslinking agent. The crosslinking agent is preferably a polyol crosslinking agent.

[0030] A compound having at least one hydroxy group can be used as the crosslinking agent. The number of hydroxy groups possessed by the crosslinking agent is at least one, preferably two or more, preferably four or less, more preferably three or less, and even more preferably two or less. In one embodiment, the crosslinking agent has two hydroxy groups in the molecule, each directly bonded to an aromatic ring and a carbon atom constituting the aromatic ring. The hydroxy group possessed by the crosslinking agent may form an ester with a carboxylic acid. That is, the crosslinking agent may have an alkylcarbonyloxy group instead of a hydroxy group. In one embodiment, the crosslinking agent has two hydroxy groups, or one hydroxy group and one alkylcarbonyloxy group, or a group having one hydroxy group and one carbon-carbon double bond (excluding those constituting the aromatic ring), or a group having one alkylcarbonyloxy group and one carbon-carbon double bond (excluding those constituting the aromatic ring). These groups are usually directly bonded to a carbon atom constituting the aromatic ring.

[0031] The aromatic ring may be either a monocyclic or polycyclic ring. The aromatic ring may be a so-called heterocyclic ring composed of not only carbon atoms but also carbon atoms and heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. In the aromatic ring, the carbon atom of the carbonyl group may constitute a ring structure.

[0032] Examples of the monocyclic aromatic ring include a monocyclic 5- to 7-membered aromatic ring, and specifically, a benzene ring and a monocyclic 5- to 7-membered aromatic heterocycle (including a 7-membered ring having a tropone structure) are preferred, a benzene ring, a furan ring, and a thiophene ring are more preferred, and a benzene ring is even more preferred.

[0033] The number of aromatic rings in the polycyclic aromatic ring is 2 or more, preferably 2 to 8, more preferably 2 to 4, even more preferably 2 or 3, and particularly preferably 2.

[0034] The polycyclic aromatic ring is preferably a polycyclic aromatic hydrocarbon ring.

[0035] The number of carbon atoms in the polycyclic aromatic hydrocarbon ring is preferably 3 to 30, more preferably 5 or more, even more preferably 6 or more, and more preferably 20 or less, even more preferably 14 or less.

[0036] The polycyclic aromatic hydrocarbon ring preferably has 2 to 4 rings, more preferably 2 or 3 rings, and even more preferably 2 rings.

[0037] Examples of the polycyclic aromatic hydrocarbon ring include: a polycyclic aromatic hydrocarbon ring in which two rings are linked via a bond, such as a biphenyl ring, a diphenylmethane ring, a diphenyl ether ring, a diphenyl sulfone ring, a diphenyl ketone ring, or a diphenyl sulfide ring; and a fused polycyclic hydrocarbon ring such as a naphthalene ring, a phenanthrene ring, an anthrahexanediolcene ring, a fluorene ring, a tetracene ring, a chrysene ring, a pyrene ring, a pentacene ring, a benzopyrene ring, a triphenylene ring, or an azulene ring.

[0038] Of these, the polycyclic aromatic hydrocarbon ring is preferably a diphenyl ether ring, a diphenyl sulfide ring, a naphthalene ring or a biphenyl ring, and more preferably a naphthalene ring.

[0039] Examples of the crosslinking agent include those described in WO 2022 / 59575, WO 2022 / 20018, WO 2022 / 210040, WO 2022 / 210041, WO 2022 / 210042, WO 2022 / 210044, WO 2022 / 264838, JP 2022-190390, WO 2022 / 264837, Japanese Patent Application No. 2021-194563, WO 2023 / 063388, PCT / JP2023 / 013950, PCT / JP2023 / 013947, Japanese Patent Application No. 2022-172558, Japanese Patent Application No. 2022-172560, Japanese Patent Application No. 2023-072544, and Japanese Patent Application No. 2022-172559. Examples of crosslinking agents include those described in the specification.

[0040] Examples of crosslinking agents include, among others, 2,7-dihydroxy-9H-fluoren-9-one, 4,4',4''-trihydroxytriphenylmethane, 1,1,1-tris(4-hydroxyphenyl)ethane, spiro[fluorene-9,9'-xanthene]-3',6'-diol, 9,9-bis(4-hydroxyphenyl)fluorene, 4,4'-biphenol, 2,6-dihydroxyanthraquinone, 2,7-dihydroxyanthraquinone, 4',7-dihydroxyisofluorene, and the like. bon, 3,6-dihydroxy-9H-xanthen-9-one, 2,7-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 6-hydroxy-3-coumaranone, 2,2,3,3-tetrafluoro-1,4-butanediol, 2,2,3,3,4,4,5,5-octafluoro-1,6-hexanediol, 4,4'-dihydroxybiphenyl, 3,3'-dihydroxybiphenyl, 4,7- Dihydroxycoumarin, 3',5'-dihydroxyacetophenone, 2-acetylhydroquinone, methyl 3,5-dihydroxybenzoate, 2',4'-dihydroxyacetophenone, 2',6'-dihydroxyacetophenone, methyl 2,4-dihydroxybenzoate, 2,2'-bis(trifluoromethyl)-[1,1'-biphenyl]-4,4'-diol, 2,2'-difluoro-[1,1'-biphenyl]-4,4'-diol, 2',4-difluoro-[1,1

[0043] 4,4'-biphenyl-2,4'-diol, 4-vinylphenyl acetate, eugenol, 4-allylphenol, 4,4'-thiodiphenol, 4,4'-dithiodiphenol, 4,4'-thiodi(o-cresol), 4,4'-dihydroxydiphenyl ether, resorcinol, 2-methylresorcinol, 5-methoxyresorcinol, 4-fluororesorcinol, 5-fluororesorcinol, 4-chlororesorcinol, and 5-bromoresorcinol are preferred.

[0041] The crosslinking agent is preferably at least one selected from the group consisting of compounds represented by general formulas (b1) to (b6).

[0042] General formula (b1): (wherein x is an integer of 1 or more, and the hydrogen atom bonded to the benzene ring may be substituted with a hydrocarbon group, a halogen atom, an alkoxy group, an alkoxycarbonyl group, or an acyl group.)

[0043] General formula (b2): (In the formula, a hydrogen atom bonded to the benzene ring (naphthalene ring) may be substituted with a hydrocarbon group, a halogen atom, an alkoxy group, an alkoxycarbonyl group, or an acyl group.)

[0044] General formula (b3): (In the formula, the hydrogen atom bonded to the benzene ring may be substituted with a hydrocarbon group, a halogen atom, an alkoxy group, an alkoxycarbonyl group, or an acyl group.)

[0045] General formula (b4): (In the formula, the hydrogen atom bonded to the benzene ring may be substituted with a hydrocarbon group, a halogen atom, an alkoxy group, an alkoxycarbonyl group, or an acyl group.)

[0046] General formula (b5): (In the formula, the hydrogen atom bonded to the benzene ring may be substituted with a hydrocarbon group, a halogen atom, an alkoxy group, an alkoxycarbonyl group, or an acyl group.)

[0047] General formula (b6): (In the formula, the hydrogen atom bonded to the benzene ring may be substituted with a hydrocarbon group, a halogen atom, an alkoxy group, an alkoxycarbonyl group, or an acyl group.)

[0048] The hydrocarbon group is preferably an alkyl group having 1 to 5 carbon atoms, more preferably a methyl group or an ethyl group. The halogen atom is preferably a fluorine atom, a chlorine atom, or a bromine atom. The alkoxy group is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a methoxy group. The alkoxycarbonyl group is preferably an alkoxycarbonyl group having 1 to 5 carbon atoms, more preferably a methoxycarbonyl group. The acyl group is preferably an acyl group having 1 to 5 carbon atoms, more preferably an acetyl group.

[0049] In general formula (b1), x represents the number of sulfur atoms connected. For example, when x is 2, the crosslinking agent has a disulfide bond (-S-S-) as a linking group connecting the carbon atom constituting the first benzene ring and the carbon atom constituting the second benzene ring. x is an integer of 1 or more, preferably an integer of 1 to 10, more preferably an integer of 1 to 3, and even more preferably 1 or 2.

[0050] In one embodiment, the cross-linking agent is at least one selected from the group consisting of methyl 3,5-dihydroxybenzoate, 4,4'-thiodiphenol, 4,4'-dihydroxydiphenyl ether, resorcinol, and 4-chlororesorcinol.

[0051] Among these, the crosslinking agent is more preferably at least one selected from the group consisting of 1,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, methyl 3,5-dihydroxybenzoate, 3',5'-dihydroxyacetophenone, 4,4'-thiodiphenol, 4,4'-dihydroxydiphenyl ether, resorcinol, and 4-chlororesorcinol, and even more preferably methyl 3,5-dihydroxybenzoate.

[0052] As the crosslinking agent, 4,4'-thiodiphenol, 4,4'-dithiodiphenol, 4,4'-dihydroxydiphenyl ether, etc. are also preferred.

[0053] The crosslinking agent is preferably a diol in which two or more hydroxybenzene rings are bonded via at least one oxygen atom or sulfur atom.

[0054] Resorcinol is also preferred as a crosslinking agent, and resorcinol may have one or more substituents, such as hydrocarbon groups such as methyl and ethyl groups, halogen atoms such as F, Cl, and Br, alkoxy groups such as methoxy, and acyl groups such as acetyl.

[0055] The crosslinking agents listed here are crosslinking agents for polyol-based fluororubbers, and in the crosslinking mechanism of the fluororubber, crosslinking is facilitated by making the rubber basic by using a compounding agent such as calcium hydroxide.

[0056] However, since the crosslinking agents listed here are highly electron-withdrawing substances as can be seen from their chemical structures, it can be assumed that dehydrogenation reactions from two or more hydroxyl groups in the molecule occur quite quickly. Therefore, it can be assumed that the crosslinking reaction occurs faster than expected, causing problems (scorch) in the rubber crosslinking molding process.

[0057] It is possible to reduce the amount of crosslinking agent to optimize the crosslinking reaction rate, but in that case, the desired rubber strength will not be obtained and the CS value is expected to deteriorate. It is also possible to reduce the amount of crosslinking accelerator or calcium hydroxide, but in that case, the dispersion of the crosslinking agent itself will also deteriorate, which is expected to cause variations in the physical properties of the crosslinked rubber.

[0058] The content of the crosslinking agent is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 6 parts by mass, still more preferably 0.7 to 5 parts by mass, and particularly preferably 0.7 to 2.5 parts by mass, relative to 100 parts by mass of the fluororubber, in order to ensure that the crosslinking reaction in the crosslinking step proceeds at an appropriate rate and that a molded product having sufficient tensile strength, elongation at break, and compression set properties at high temperatures, and appropriate hardness can be obtained.

[0059] (c) Organic Acid The fluororubber composition of the present disclosure contains at least one organic acid (c) selected from the group consisting of organic acids having 3 to 10 carbon atoms and one acid group per molecule, and organic acids having 2 to 10 carbon atoms and two or more acid groups per molecule. Because the fluororubber composition of the present disclosure contains the organic acid (c), the crosslinking induction time (T10) during crosslinking is longer than that of conventional fluororubber compositions containing the same components except for not containing the organic acid (c), and the occurrence of molding defects can be suppressed. Furthermore, by using the fluororubber composition of the present disclosure, it is possible to obtain fluororubber molded articles having excellent properties, similar to those obtained when conventional fluororubber compositions are used.

[0060] An organic acid is a compound composed of an organic group and an acid group bonded to the organic group. When the acid group contains a carbon atom, the number of carbon atoms in the organic acid is the total number of carbon atoms constituting the organic group and the acid group.

[0061] The organic acid used in the present disclosure is an organic acid having one acid group in the molecule, or an organic acid having two or more acid groups in the molecule. The number of carbon atoms in an organic acid having one acid group in the molecule is 3 to 10, preferably 9 or less, and more preferably 8 or less. The number of carbon atoms in an organic acid having two or more acid groups in the molecule is 2 to 10, preferably 9 or less, and more preferably 8 or less.

[0062] If the number of carbon atoms in the organic acid is too large, the crosslinking induction time (T10) cannot be extended, whereas if the number of carbon atoms in the organic acid is too small, not only the crosslinking induction time (T10) cannot be extended, but also the physical properties of the molded article, such as breaking strength, may be reduced.

[0063] The acid group of the organic acid is not particularly limited as long as it has a hydrogen atom that can be ionized as a proton, and examples thereof include a carboxyl group, a sulfo group, a sulfino group, a phosphate group, and a phosphonate group. The acid group of the organic acid may form a base together with a cation. The organic acid may also be a hydrate.

[0064] The number of acid groups in the organic acid having two or more acid groups in the molecule is preferably 2 to 5, and more preferably 2 to 3, since the crosslinking induction time (T10) during crosslinking can be further extended.

[0065] As the organic acid, an organic carboxylic acid is preferred because it can further lengthen the crosslinking induction time (T10) during crosslinking. Furthermore, as the organic acid, an organic acid containing no fluorine atoms is preferred because it can further lengthen the crosslinking induction time (T10) during crosslinking, and an organic carboxylic acid containing no fluorine atoms is more preferred.

[0066] The organic acid is preferably at least one selected from the group consisting of citric acid, phthalic acid, benzoic acid, adipic acid, and oxalic acid, because it can further lengthen the crosslinking induction time (T10) during crosslinking, and more preferably at least one selected from the group consisting of citric acid, phthalic acid, benzoic acid, and adipic acid.

[0067] The crosslinking induction time (T10 Ａ ) is the crosslinking induction time (T10) of the fluororubber composition (B) containing the same components as the fluororubber composition (A) except that it does not contain an organic acid. Ｂ The fluororubber composition of the present disclosure contains a specific organic acid, and therefore has a longer crosslink induction time (T10) than a conventional fluororubber composition containing the same components except that it does not contain an organic acid, and therefore can provide a fluororubber molded article that exhibits excellent properties while suppressing molding defects.

[0068] The content of the organic acid is preferably 0.05 to 10 parts by mass, more preferably 0.07 parts by mass or more, more preferably 6.0 parts by mass or less, still more preferably 4.0 parts by mass or less, and particularly preferably 2.0 parts by mass or less, relative to 100 parts by mass of the fluororubber, because the crosslinking induction time (T10) during crosslinking can be further extended.

[0069] It is also preferable to select the content of the organic acid in the fluororubber composition in consideration of the number of acid groups that the organic acid has. In one embodiment, from the viewpoint of further extending the crosslinking induction time (T10) during crosslinking, the number of acid groups N (×10 －２ N (×10 －２ N(×10)=(amount of organic acid (parts by mass) per 100 parts by mass of rubber) / (molecular weight of organic acid)×(number of acid groups per molecule of organic acid)×100 －２ ) is the number of acid groups of the organic acid per 100 parts by mass of rubber, N (× 10 －２ (pieces).

[0070] Number of acid groups N (×10 －２ The number of acid groups N (×10 －２ The number of particles may be 0.25 or more, 1.30 or less, 1.00 or less, or 0.70 or less.

[0071] (d) Crosslinking Accelerator The fluororubber composition of the present disclosure preferably contains a crosslinking accelerator. The use of a crosslinking accelerator can accelerate the crosslinking reaction by promoting the formation of intramolecular double bonds in the dehydrofluorination reaction of the fluororubber main chain. Even when an onium salt is used as the crosslinking agent, a crosslinking accelerator can be used together with the crosslinking agent, but it is not necessarily required. The amount of crosslinking accelerator can be adjusted appropriately depending on the crosslinking conditions and the physical properties of the molded product. Increasing the amount of crosslinking accelerator speeds up the crosslinking reaction or enables crosslinking at a lower temperature, but tends to worsen the compression set properties. Conversely, reducing the amount of crosslinking accelerator slows down the crosslinking reaction, but tends to improve the compression set properties.

[0072] An onium compound is generally used as a crosslinking accelerator for a polyol crosslinking system. The onium compound is not particularly limited, and examples thereof include ammonium salts such as quaternary ammonium salts, phosphonium salts such as quaternary phosphonium salts, and sulfonium salts, with quaternary ammonium salts and quaternary phosphonium salts being preferred.

[0073] The quaternary ammonium salt is not particularly limited, and examples thereof include 8-methyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, 8-methyl-1,8-diazabicyclo[5,4,0]-7-undecenium iodide, 8-methyl-1,8-diazabicyclo[5,4,0]-7-undecenium hydroxide, and 8-methyl-1,8-diazabicyclo[5,4,0]-7-undecenium methylsulfate. , 8-ethyl-1,8-diazabicyclo[5,4,0]-7-undecenium bromide, 8-propyl-1,8-diazabicyclo[5,4,0]-7-undecenium bromide, 8-dodecyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, 8-dodecyl-1,8-diazabicyclo[5,4,0]-7-undecenium hydroxide, 8-eicosyl-1,8-diazabicyclo[5,4,0]-7 -undecenium chloride, 8-tetracosyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, 8-benzyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride (hereinafter referred to as DBU-B), 8-benzyl-1,8-diazabicyclo[5,4,0]-7-undecenium hydroxide, 8-phenethyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, 8-(3-phenylpropyl)-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, benzyldimethyloctadecylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium chloride, benzyltributylammonium chloride, benzyltriethylammonium chloride, tetrabutylammonium hydrogen sulfate, tetrabutylammonium hydroxide, and the like. Among these, DBU-B or benzyldimethyloctadecylammonium chloride is preferred from the viewpoint of crosslinkability and physical properties of the crosslinked product.

[0074] Furthermore, the quaternary phosphonium salt is not particularly limited, and examples thereof include tetrabutylphosphonium chloride, benzyltriphenylphosphonium chloride (hereinafter referred to as BTPPC), benzyltrimethylphosphonium chloride, benzyltributylphosphonium chloride, tributylallylphosphonium chloride, tributyl-2-methoxypropylphosphonium chloride, and benzylphenyl(dimethylamino)phosphonium chloride. Among these, benzyltriphenylphosphonium chloride (BTPPC) is preferred from the viewpoints of crosslinkability and the physical properties of the crosslinked product.

[0075] The content of the crosslinking accelerator is preferably 0.1 to 10 parts by mass, more preferably 0.1 to 3 parts by mass, still more preferably 0.2 to 1 part by mass, and particularly preferably 0.3 to 0.8 parts by mass, relative to 100 parts by mass of the fluororubber, because the crosslinking reaction proceeds at an appropriate rate and a molded product with even better compression set properties at high temperatures can be obtained.

[0076] (e) Acid Acceptor The fluororubber composition of the present disclosure may further contain an acid acceptor. By containing an acid acceptor, the crosslinking reaction of the fluororubber composition proceeds more smoothly, and the compression set properties at high temperatures are further improved.

[0077] Examples of the acid acceptor include metal oxides such as magnesium oxide, calcium oxide, bismuth oxide, and zinc oxide, metal hydroxides such as calcium hydroxide, alkali metal silicates such as hydrotalcite and sodium metasilicate described in JP-T-2011-522921A, and metal salts of weak acids described in JP-A-2003-277563A. Examples of the metal salts of weak acids include carbonates, benzoates, oxalates, and phosphites of Ca, Sr, Ba, Na, and K.

[0078] As the acid acceptor, at least one selected from the group consisting of metal oxides, metal hydroxides, alkali metal silicates, metal salts of weak acids, and hydrotalcite is preferred, as this allows for the production of molded articles with even better compression set properties at high temperatures, with sodium metasilicate hydrate, calcium hydroxide, magnesium oxide, bismuth oxide, and hydrotalcite being more preferred, and calcium hydroxide and magnesium oxide being even more preferred.Furthermore, when the resulting molded article requires good water resistance, acid resistance, or resistance to organic acid esters including biodiesel, at least one selected from the group consisting of bismuth oxide and hydrotalcite is preferred as the acid acceptor.

[0079] In the fluororubber composition, the content of the acid acceptor is preferably 0.1 to 100 parts by mass, more preferably 1 to 50 parts by mass, even more preferably 1 to 30 parts by mass, and particularly preferably 1 to 20 parts by mass, per 100 parts by mass of the fluororubber, since a molded product with even better compression set properties at high temperatures can be obtained.

[0080] (f) Other Components If necessary, the fluororubber composition may be blended with various additives that are typically blended into fluororubber compositions, such as fillers (carbon black, bituminous coal, barium sulfate, diatomaceous earth, calcined clay, talc, wollastonite, carbon nanotubes, etc.), processing aids (wax, etc.), plasticizers, colorants, stabilizers, tackifiers (coumarone resin, coumarone-indene resin, etc.), release agents, electrical conductivity imparting agents, thermal conductivity imparting agents, surface non-tackifying agents, flexibility imparting agents, heat resistance improvers, flame retardants, foaming agents, and antioxidants described in WO 2012 / 023485. One or more commonly used crosslinking agents and crosslinking accelerators different from the above may also be blended.

[0081] As carbon black, thermal carbon black and furnace carbon black are preferred, with MT carbon black, FT carbon black, and SRF carbon black being more preferred. When carbon black with a relatively large particle size, such as MT carbon black or FT carbon black, is blended, molded articles with excellent compression set properties can be obtained, while when carbon black with a fine particle size is blended, molded articles with excellent strength and elongation can be obtained. By blending different grades in combination, the above properties can be balanced.

[0082] As fillers other than carbon black, barium sulfate and wollastonite are preferred.

[0083] The processing aid is not particularly limited, but examples thereof include aliphatic amines such as stearylamine, fatty acid esters such as stearic acid esters and sebacate esters, fatty acid amides such as stearic acid amide, long-chain alkyl alcohols, natural waxes, polyethylene waxes, phosphate esters such as tricresyl phosphate, and silicone-based processing aids. If necessary, blending two or more types in appropriate amounts can improve the balance between mold releasability during molding and the physical properties of the molded product.

[0084] The content of the filler such as carbon black is not particularly limited, but is preferably 0 to 300 parts by mass, more preferably 1 to 150 parts by mass, even more preferably 2 to 100 parts by mass, and particularly preferably 2 to 75 parts by mass, relative to 100 parts by mass of the fluororubber.

[0085] The content of processing aids such as wax is preferably 0 to 10 parts by mass, more preferably 0 to 5 parts by mass, and particularly preferably 0 to 2 parts by mass, relative to 100 parts by mass of the fluororubber. When processing aids, plasticizers, or release agents are used, the mechanical properties and sealing properties of the resulting molded article tend to decrease, so it is necessary to adjust the content of these agents within a range that allows the desired properties of the resulting molded article.

[0086] The fluororubber composition may contain a dialkyl sulfone compound. The inclusion of a dialkyl sulfone compound increases the crosslinking efficiency of the fluororubber composition, accelerates the crosslinking rate, further improves compression set properties, and improves the fluidity of the rubber material. Examples of dialkyl sulfone compounds include dimethyl sulfone, diethyl sulfone, dibutyl sulfone, methyl ethyl sulfone, diphenyl sulfone, and sulfolane. Among these, sulfolane is preferred from the viewpoints of crosslinking efficiency and compression set properties, as well as its suitable boiling point. The content of the dialkyl sulfone compound is preferably 0 to 10 parts by mass, more preferably 0 to 5 parts by mass, and particularly preferably 0 to 3 parts by mass, per 100 parts by mass of the fluororubber. When the fluororubber composition of the present disclosure contains a dialkyl sulfone compound, the lower limit of the content of the dialkyl sulfone compound may be, for example, 0.1 parts by mass or more per 100 parts by mass of the fluororubber.

[0087] The dialkyl sulfone compound and the processing aid may be blended together, as this provides a good balance of crosslinking rate, flowability of the rubber material during molding, mold releasability during molding, and mechanical properties of the molded product.

[0088] The fluororubber composition can be obtained by kneading the fluororubber (a), the crosslinking agent (b), the organic acid (c), the crosslinking accelerator (d), the acid acceptor (e), and other components (f) using a commonly used rubber kneading device, such as a roll, a kneader, a Banbury mixer, an internal mixer, or a twin-screw extruder.

[0089] In order to uniformly disperse each component in the rubber, a method may be used in which the fluororubber (a), crosslinking agent (b), organic acid (c), and crosslinking accelerator (d) are kneaded while melting them at a high temperature of 100 to 200°C using a closed kneading device such as a kneader, and then the acid acceptor (d), other components (e), etc. are kneaded at a relatively low temperature below this temperature.

[0090] Furthermore, the dispersibility can be further improved by mixing the fluororubber (a), the crosslinking agent (b), the organic acid (c), the crosslinking accelerator (d), the acid acceptor (e), and other components (f), and then leaving the mixture at room temperature for 12 hours or more and then kneading it again.

[0091] <Molded Article> The molded article of the present disclosure can be obtained by crosslinking the fluororubber composition. Alternatively, the molded article of the present disclosure can be obtained by molding and crosslinking the fluororubber composition. The fluororubber composition can be molded by a conventionally known method. The molding and crosslinking methods and conditions may be within the range of known methods and conditions for the molding and crosslinking employed. The order of molding and crosslinking is not limited, and molding may be followed by crosslinking, crosslinking may be followed by molding, or molding and crosslinking may be performed simultaneously.

[0092] Examples of molding methods include, but are not limited to, compression molding, casting, injection molding, extrusion molding, and rotocure molding. Examples of crosslinking methods that can be used include steam crosslinking, heat crosslinking, and radiation crosslinking, with steam crosslinking and heat crosslinking being preferred. Specific crosslinking conditions, which are not limited to, are typically a temperature range of 140 to 250°C, a crosslinking time of 1 minute to 24 hours, and can be determined appropriately depending on the types of crosslinking agent (b), crosslinking accelerator (d), acid acceptor (e), and the like.

[0093] Furthermore, by heating the obtained molded article in an oven or the like, it is possible to improve mechanical properties such as tensile strength, heat resistance, and high-temperature compression set properties, etc. Specific crosslinking conditions, which are not limited to these, are usually in the temperature range of 140 to 300°C and the time range of 30 minutes to 72 hours, and may be appropriately determined depending on the types of crosslinking agent (b), crosslinking accelerator (d), acid acceptor (e), etc.

[0094] The molded article of the present disclosure has excellent properties such as heat resistance, oil resistance, chemical resistance, flexibility, etc., and further has excellent compression set properties at high temperatures. Therefore, the molded article of the present disclosure is generally used in areas that come into contact with other materials and slide, seal or seal other materials or substances, or are intended for vibration and sound insulation, and can be used as various parts in various fields such as the automotive industry, the aircraft industry, and the semiconductor industry.

[0095] Examples of fields in which they are used include semiconductor-related fields, automobiles, aircraft, space and rockets, ships, chemicals such as chemical plants, pharmaceuticals such as medicines, photography such as developing machines, printing such as printing machines, painting such as painting equipment, analytical and physicochemical machinery such as analytical instruments and meters, food equipment including food plant equipment and household goods, food beverage manufacturing equipment, pharmaceutical manufacturing equipment, medical parts, chemical transport equipment, nuclear power plant equipment, steel such as iron plate processing equipment, general industry, electricity, fuel cells, electronic parts, optical equipment parts, space equipment parts, petrochemical plant equipment, energy resource exploration and mining equipment parts such as oil and gas, oil refining, and oil transportation equipment parts.

[0096] Examples of uses of the molded articles include various sealing materials and packings such as rings, packings, gaskets, diaphragms, oil seals, bearing seals, lip seals, plunger seals, door seals, lip and face seals, gas delivery plate seals, wafer support seals, barrel seals, etc. As sealing materials, they can be used in applications requiring heat resistance, solvent resistance, chemical resistance, and non-stickiness.

[0097] It can also be used as a tube, hose, roll, various rubber rolls, flexible joint, rubber plate, coating, belt, damper, valve, valve seat, valve body, chemical-resistant coating material, laminating material, lining material, etc.

[0098] The cross-sectional shape of the ring, packing, and seal may be of various shapes, specifically, for example, square, O-shaped, ferrule-shaped, or irregular shapes such as D-shaped, L-shaped, T-shaped, V-shaped, X-shaped, and Y-shaped.

[0099] In the semiconductor-related fields, the present invention can be used, for example, in semiconductor manufacturing equipment, liquid crystal panel manufacturing equipment, plasma panel manufacturing equipment, plasma display panel manufacturing equipment, plasma addressed liquid crystal panel manufacturing equipment, organic EL panel manufacturing equipment, field emission display panel manufacturing equipment, solar cell substrate manufacturing equipment, semiconductor conveying equipment, etc. Examples of such equipment include CVD equipment, gas control equipment such as semiconductor gas control equipment, dry etching equipment, wet etching equipment, plasma etching equipment, reactive ion etching equipment, reactive ion beam etching equipment, sputter etching equipment, ion beam etching equipment, oxidation diffusion equipment, sputtering equipment, ashing equipment, plasma ashing equipment, cleaning equipment, ion implantation equipment, plasma CVD equipment, exhaust equipment, exposure equipment, polishing equipment, film formation equipment, dry etching cleaning equipment, UV / O ３ Cleaning equipment, ion beam cleaning equipment, laser beam cleaning equipment, plasma cleaning equipment, gas etching cleaning equipment, extraction cleaning equipment, Soxhlet extraction cleaning equipment, high temperature and high pressure extraction cleaning equipment, microwave extraction cleaning equipment, supercritical extraction cleaning equipment, cleaning equipment using hydrofluoric acid, hydrochloric acid, sulfuric acid, ozone water, etc., steppers, coater developers, CMP equipment, excimer laser exposure machines, chemical liquid piping, gas piping, NF ３ Plasma treatment, O ２ Examples of such equipment include equipment for performing plasma treatment such as plasma treatment and fluorine plasma treatment, heat treatment film formation equipment, wafer transport equipment, wafer cleaning equipment, silicon wafer cleaning equipment, silicon wafer processing equipment, equipment used in LP-CVD processes, equipment used in lamp annealing processes, and equipment used in reflow processes.

[0100] Specific uses in the semiconductor-related field include, for example, various sealing materials such as O-rings and gaskets for gate valves, quartz windows, chambers, chamber lits, gates, bell jars, couplings, and pumps; various sealing materials such as O-rings for resist developer and stripper solutions, hoses and tubes; linings and coatings for resist developer tanks, stripper tanks, wafer cleaning solution tanks, and wet etching tanks; pump diaphragms; rolls for transporting wafers; hose tubes for wafer cleaning solutions; sealing materials for clean facilities such as sealants for clean facilities in clean rooms and the like; sealing materials for storage cabinets for storing semiconductor manufacturing equipment and devices such as wafers; and diaphragms for transporting chemical solutions used in the process of manufacturing semiconductors.

[0101] In the above-mentioned automotive field, the material can be used in the engine body, main driving system, valve train system, lubrication and cooling system, fuel system, intake and exhaust system, transmission system of the drive system, steering system of the chassis, brake system, basic electrical components, control system electrical components, equipment electrical components, etc. The above-mentioned automotive field also includes motorcycles.

[0102] In the engine main body and its peripheral devices as described above, molded products can be used for various sealing materials that require heat resistance, oil resistance, fuel oil resistance, engine cooling antifreeze resistance, and steam resistance. Examples of such sealing materials include seals such as gaskets, shaft seals, and valve stem seals; non-contact or contact type packings such as self-sealing packings, piston rings, split ring type packings, mechanical seals, and oil seals; bellows, diaphragms, hoses, and tubes; as well as electric wires, cushioning materials, vibration-proofing materials, and various sealing materials used in belt AT devices.

[0103] Specific uses in the above fuel systems include O-rings used in fuel injectors, cold start injectors, fuel line quick connectors, sender flange quick connectors, fuel pumps, fuel tank quick connectors, gasoline mixing pumps, gasoline pumps, fuel tube bodies, fuel tube connectors, injectors, etc.; seals used in intake system manifolds, fuel filters, pressure regulating valves, canisters, fuel tank caps, fuel pumps, fuel tanks, fuel tank sender units, fuel injection devices, high-pressure fuel pumps, fuel line connector systems, pump timing control valves, suction control valves, solenoid sub-assemblies, fuel cut valves, etc.; canister purge solenoid valve seals, onboard refueling vapor recovery (ORVR) valve seals, fuel pump oil seals, fuel sender seals, fuel tank rollover valve seals, filler seals, injector seals, filler cap seals, filler cap valves, etc. Seals; hoses such as fuel hoses, fuel supply hoses, fuel return hoses, vapor (evaporative) hoses, vent (breather) hoses, filler hoses, filler neck hoses, hoses inside fuel tanks (in-tank hoses), carburetor control hoses, fuel inlet hoses, and fuel breather hoses; gaskets used in fuel filters and fuel line connector systems, and flange gaskets used in carburetors; line materials such as vapor recovery lines, fuel feed lines, and vapor / ORVR lines; diaphragms used in canisters, ORVRs, fuel pumps, fuel tank pressure sensors, gasoline pumps, carburetor sensors, composite air control devices (CACs), pulsation dampers, canisters, autococks, and pressure regulator diaphragms for fuel injection systems; fuel pump valves, carburetor needle valves, rollover check valves, check valves; vents (breathers), and tubes used inside fuel tanks; tank packings for fuel tanks, etc., and packings for carburetor acceleration pump pistons;Examples include fuel sender vibration isolation parts for fuel tanks; O-rings and diaphragms for controlling fuel pressure; accelerator pump cups; in-tank fuel pump mounts; injector cushion rings for fuel injection systems; injector seal rings; carburetor needle valve core valves; carburetor accelerator pump pistons; valve seats for compound air control systems (CAC); fuel tank bodies; and sealing parts for solenoid valves.

[0104] Specific uses in the above-mentioned brake systems include diaphragms used in master bags, hydraulic brake hose air brakes, brake chambers of air brakes, etc.; hoses used in brake hoses, brake oil hoses, vacuum brake hoses, etc.; various sealing materials such as oil seals, O-rings, packing, and brake piston seals; atmospheric valves and vacuum valves for master bags, and check valves for brake valves; piston cups (rubber cups) and brake cups for master cylinders; boots for master cylinders and vacuum boosters of hydraulic brakes, wheel cylinders of hydraulic brakes, and O-rings and grommets for anti-lock braking systems (ABS).

[0105] Specific examples of uses of the basic electrical components include insulators and sheaths for electrical wires (harnesses), tubes for harness exterior parts, and grommets for connectors.

[0106] Specific examples of applications in electrical control components include coating materials for various sensor wires.

[0107] Specific examples of applications for the above-mentioned electrical equipment parts include O-rings and packings for car air conditioners, cooler hoses, high-pressure air conditioner hoses, air conditioner hoses, gaskets for electronic throttle units, plug boots for direct ignition, and distributor diaphragms. The material can also be used to bond electrical parts.

[0108] Specific uses in the intake and exhaust systems include packings used in intake manifolds, exhaust manifolds, etc., and throttle body packings for throttles; diaphragms used in EGR (exhaust gas recirculation), pressure control (BPT), wastegates, turbo wastegates, actuators, variable turbine geometry (VTG) turbo actuators, exhaust purification valves, etc.; EGR (exhaust gas recirculation) control hoses, emission control hoses, turbocharger turbo oil hoses (supply), turbo oil hoses (return), turbo air hoses, intake ... Examples of such hoses include intercooler hoses, turbocharger hoses, hoses connected to the compressor of a turbo engine equipped with an intercooler, exhaust gas hoses, air intake hoses, turbo hoses, DPF (diesel particulate filter) sensor hoses, etc.; air ducts and turbo air ducts; intake manifold gaskets; EGR sealing materials, afterburn prevention valve seats for AB valves, turbine shaft seals (for turbochargers, etc.), and sealing members used in grooved parts such as rocker covers and air intake manifolds used in automobile engines.

[0109] Other applications include seals for vapor recovery canisters, catalytic converters, exhaust gas sensors, oxygen sensors, etc., as well as seals for vapor recovery and vapor canister solenoid armatures; intake manifold gaskets, etc.

[0110] In addition, in diesel engine parts, the material can be used as an O-ring seal for a direct injection injector, a rotary pump seal, a control diaphragm, a fuel hose, an EGR, a priming pump, a diaphragm for a boost compensator, etc. Furthermore, the material can be used for an O-ring, a seal material, a hose, a tube, a diaphragm, a gasket material, a pipe used in a urea SCR system, a urea water tank body of a urea SCR system, a seal material for the urea water tank, etc.

[0111] Specific examples of applications in the transmission system include transmission-related bearing seals, oil seals, O-rings, packing, torque converter hoses, etc. Also included are transmission oil seals, AT transmission oil hoses, ATF hoses, O-rings, packing, etc.

[0112] Transmissions include AT (automatic transmission), MT (manual transmission), CVT (continuously variable transmission), and DCT (dual clutch transmission).

[0113] Other examples include oil seals, gaskets, O-rings, and packings for manual or automatic transmissions, oil seals, gaskets, O-rings, and packings for continuously variable transmissions (belt type or toroidal type), as well as packings for ATF linear solenoids, oil hoses for manual transmissions, ATF hoses for automatic transmissions, and CVTF hoses for continuously variable transmissions (belt type or toroidal type).

[0114] Specific examples of uses in steering systems include power steering oil hoses and high-pressure power steering hoses.

[0115] Examples of forms used in the engine body of an automobile engine include gaskets such as cylinder head gaskets, cylinder head cover gaskets, oil pan packings, and general gaskets; seals such as O-rings, packings, and timing belt cover gaskets; hoses such as control hoses; vibration-isolating rubber for engine mounts; control valve diaphragms; and camshaft oil seals.

[0116] In the main driving system of an automobile engine, it can be used as a shaft seal such as a crankshaft seal or a camshaft seal.

[0117] In the valve train of an automobile engine, it can be used for valve stem oil seals of engine valves, valve seats of butterfly valves, etc.

[0118] In the lubrication and cooling systems of automobile engines, the material can be used for engine oil cooler hoses, oil return hoses, seal gaskets for engine oil coolers, water hoses around radiators, radiator seals, radiator gaskets, radiator O-rings, vacuum pump oil hoses for vacuum pumps, as well as radiator hoses, radiator tanks, oil pressure diaphragms, fan coupling seals, etc.

[0119] Specific examples of uses in the automotive field include engine head gaskets, oil pan gaskets, manifold packings, oxygen sensor seals, oxygen sensor bushings, and nitrogen oxide (NO ｘ ) sensor seal, nitric oxide (NO ｘ) Sensor bushings, sulfur oxide sensor seals, temperature sensor seals, temperature sensor bushings, diesel particle filter sensor seals, diesel particle filter sensor bushings, injector O-rings, injector packings, fuel pump O-rings and diaphragms, gearbox seals, power piston packings, cylinder liner seals, valve stem seals, static valve stem seals, dynamic valve stem seals, automatic transmission front pump seals, rear axle pinion seals, universal joint gaskets, speedometer pinion seals, foot brake piston cups, O-rings and oil seals for torque transmission devices, seals and bearing seals for exhaust gas re-burning devices, hoses for re-burning devices, Carburetor sensor diaphragms, anti-vibration rubber (engine mounts, exhaust parts, muffler hangers, suspension bushings, center bearings, strut bumper rubber, etc.), suspension anti-vibration rubber (strut mounts, bushings, etc.), drive system anti-vibration rubber (dampers, etc.), fuel hoses, EGR tubes and hoses, twin carburetor tubes, carburetor needle valve core valves, carburetor flange gaskets, oil hoses, oil cooler hoses, ATF hoses, cylinder head gaskets, water pump seals, gearbox seals, needle valve tips, motorcycle reed valve leads, automobile engine oil seals, gasoline hose gun seals, car air conditioner seals, engine intercooler rubber hoses, fuel line connector devices (fuel line connectors)systems), CAC valves, needle tips, engine wiring, filler hoses, car air conditioner O-rings, intake gaskets, fuel tank materials, distributor diaphragms, water hoses, clutch hoses, PS hoses, AT hoses, master back hoses, heater hoses, air conditioning hoses, ventilation hoses, oil filler caps, PS rack seals, rack and pinion boots, CVJ boots, ball joint dust covers, strut dust covers, weather strips, glass runs, center unit packing parts, body sight welts, bumper rubber, door latches, dash insulators, high tension cords, flat belts, poly V-belts, timing belts, toothed belts, V-ribbed belts, tires, wiper blades, diaphragms and plungers for LPG vehicle regulators, diaphragms and valves for CNG vehicle regulators, DME compatible rubber parts, auto tensioner diaphragms and boots, idle speed control diaphragms and valves, auto speed control actuators, vacuum pump diaphragms, check valves and plungers, O.P.S. diaphragms and O-rings, gasoline pressure relief valves, engine cylinder sleeve O-rings and gaskets, wet cylinder sleeve O-rings and gaskets, differential gear seals and gaskets (gear oil seals and gaskets), power steering device seals and gaskets (PSF seals and gaskets), shock absorber seals and gaskets (SAF seals and gaskets), constant velocity joint seals and gaskets, wheel bearing seals and gaskets, metal gasket coating agents, caliper seals, boots, wheel bearing seals, and bladders used in tire vulcanization molding.

[0120] In the above-mentioned aircraft, space / rocket and ship fields, the composition can be used particularly in fuel systems and lubricating oil systems.

[0121] In the aircraft field, the composition can be used, for example, as various sealing parts for aircraft, various aircraft parts for aircraft engine oil applications, jet engine valve stem seals, gaskets and O-rings, rotating shaft seals, gaskets for hydraulic equipment, firewall seals, fuel supply hoses, gaskets and O-rings, aircraft cables, oil seals and shaft seals, etc.

[0122] In the space and rocket fields, the material can be used, for example, as lip seals, diaphragms, and O-rings for spacecraft, jet engines, missiles, etc., O-rings for gas turbine engine oil, and vibration isolation pads for missile ground control.

[0123] Furthermore, in the field of ships, the composition can be used, for example, as a stern seal for a screw propeller shaft, an intake and exhaust valve stem seal for a diesel engine, a valve seal for a butterfly valve, a valve seat or shaft seal for a butterfly valve, a shaft seal for a butterfly valve, a stern tube seal, a fuel hose, a gasket, an O-ring for an engine, a cable for a ship, an oil seal for a ship, a shaft seal for a ship, etc.

[0124] In the chemical field such as the above-mentioned chemical plants and the chemical field such as pharmaceuticals, the material can be used in processes that require high chemical resistance, for example, processes for producing chemical products such as pharmaceuticals, agricultural chemicals, paints, and resins.

[0125] Specific uses in the chemical and pharmaceutical fields include seals used in chemical equipment, chemical pumps and flow meters, chemical piping, heat exchangers, pesticide sprayers, pesticide transfer pumps, gas piping, fuel cells, analytical equipment and physical and chemical equipment (for example, column fittings for analytical equipment and instruments), shrink joints for flue gas desulfurization equipment, nitric acid plants, power plant turbines, etc., seals used in medical sterilization processes, plating solution seals, roller seals for papermaking belts, and wind tunnel joint seals; O-rings used in chemical equipment such as reactors and mixers, analytical equipment and instruments, chemical pumps, pump housings, valves, tachometers, etc., O-rings for mechanical seals, and O-rings for compressor sealing; packings used in high-temperature vacuum dryers, tube joints for gas chromatography and pH meters, etc., and glass cooling seals for sulfuric acid manufacturing equipment. Examples of suitable applications include: instrument packing; diaphragms used in diaphragm pumps, analytical equipment, and physical and chemical equipment; gaskets used in analytical equipment and meters; ferrules used in analytical equipment and meters; valve seats; U-cups; linings used in chemical equipment, gasoline tanks, wind tunnels, etc., and corrosion-resistant linings for anodized aluminum tanks; coatings for plating masking jigs; valve parts for analytical equipment and physical and chemical equipment; expansion joints in flue gas desulfurization plants; acid-resistant hoses for concentrated sulfuric acid, etc., chlorine gas transfer hoses, oil-resistant hoses, and rainwater drain hoses for benzene and toluene storage tanks; chemical-resistant tubing and medical tubing used in analytical equipment, physical and chemical equipment, etc.; trichlene-resistant rolls and dyeing rolls for textile dyeing; pharmaceutical stoppers; medical rubber stoppers; chemical solution bottles, chemical solution tanks, bags, chemical containers; and protective equipment such as strong acid-resistant and solvent-resistant gloves and boots.

[0126] In the photographic field such as the developing machines, the printing field such as printing machines, and the painting field such as painting equipment, the material can be used as rolls, belts, seals, valve parts, etc. in dry copying machines.

[0127] Specific uses in the above-mentioned fields of photography, printing and coating include surface layers of transfer rolls in copiers, cleaning blades in copiers, and belts in copiers; rolls (for example, fixing rolls, pressure rolls, and the like) and belts for office automation equipment such as copiers, printers and facsimiles; rolls, roll blades and belts in PPC copiers; rolls in film developing machines and X-ray film developing machines; printing rolls, scrapers, tubes, valve parts and belts in printing machines; ink tubes, rolls and belts in printers; coating rolls, scrapers, tubes and valve parts in coating and painting equipment; developing rolls, gravure rolls, guide rolls, guide rolls in magnetic tape production coating lines, gravure rolls and coating rolls in magnetic tape production coating lines, etc.

[0128] In the food equipment field, including the food plant equipment and household goods, the present invention can be used in food manufacturing processes, food transporters, or food storage devices.

[0129] Specific uses in the food equipment field include seals for plate-type heat exchangers, solenoid valve seals for vending machines, packing for thermos pots, sanitary pipe packing, packing for pressure cookers, water heater seals, heat exchanger gaskets, diaphragms and packing for food processing equipment, rubber materials for food processing equipment (for example, heat exchanger gaskets, diaphragms, various seals such as O-rings, piping, hoses, sanitary packing, valve packing, and filling packing used as a joint between the mouth of a bottle or the like and the filler during filling), etc. Further examples include packings, gaskets, tubes, diaphragms, hoses, and joint sleeves used in products such as alcoholic beverages and soft drinks, filling equipment, food sterilization equipment, brewing equipment, water heaters, various automatic food vending machines, etc.

[0130] In the field of nuclear power plant equipment, the material can be used for check valves and pressure reducing valves around nuclear reactors, and seals for uranium hexafluoride enrichment equipment.

[0131] Specific uses in the above general industrial fields include sealing materials for hydraulic equipment such as machine tools, construction machinery, and hydraulic machinery; seals and bearing seals for hydraulic and lubricating machinery; sealing materials used for mandrels and the like; seals used for windows of dry cleaning equipment and the like; cyclotron seals and (vacuum) valve seals, proton accelerator seals, automatic packaging machine seals, pump diaphragms for airborne sulfur dioxide and chlorine gas analyzers (pollution measuring instruments), snake pump linings, printing press rolls and belts, transport belts (conveyor belts), squeeze rolls for pickling iron plates and the like, robot cables, solvent squeeze rolls for aluminum rolling lines and the like, coupler O-rings, acid-resistant cushioning materials, dust seals and lip rubbers for sliding parts of cutting machinery, gaskets for food waste incineration machines, friction materials, metal or rubber surface modifiers, coating materials, and the like. It can also be used as gaskets and sealing materials for equipment used in papermaking processes, sealants for clean room filter units, construction sealants, protective coatings for concrete and cement, glass cloth impregnation materials, polyolefin processing aids, polyethylene moldability improving additives, fuel containers for small generators and lawn mowers, pre-coated metals obtained by applying a primer treatment to metal plates, etc. In addition, it can also be used as sheets and belts by impregnating woven fabric and baking it.

[0132] Specific examples of use in the steel industry include iron plate processing rolls in iron plate processing equipment.

[0133] Specific applications in the electrical field include insulating oil caps for bullet trains, venting seals for liquid-sealed transformers, transformer seals, oil well cable jackets, seals for ovens such as electric furnaces, window frame seals for microwave ovens, sealants used to bond the wedge and neck of a CRT, sealants for halogen lamps, fixing agents for electrical components, sealants for the terminal treatment of sheathed heaters, and sealants used for insulating and moisture-proofing the lead wire terminals of electrical equipment. The material can also be used as a coating material for oil-resistant and heat-resistant electric wires, highly heat-resistant electric wires, chemical-resistant electric wires, highly insulating electric wires, high-voltage power transmission lines, cables, electric wires used in geothermal power generation equipment, and electric wires used around automobile engines. It can also be used as an oil seal or shaft seal for vehicle cables. Furthermore, it can also be used as an electrical insulating material (for example, insulating spacers for various electrical devices, insulating tape for cable joints and ends, and heat-shrinkable tubing), and as a material for electrical and electronic devices used in high-temperature environments (for example, lead wire materials for motors and wire materials for high-temperature furnaces).It can also be used as an encapsulating layer or protective film (back sheet) for solar cells.

[0134] In the field of fuel cells, the material can be used as a sealing material between electrodes and between electrodes and separators in polymer electrolyte fuel cells, phosphate fuel cells, etc., as well as seals, packings, and separators for piping for hydrogen, oxygen, generated water, etc.

[0135] In the field of electronic parts, it can be used as a raw material for heat dissipation materials, electromagnetic wave shielding materials, gaskets for computer hard disk drives (magnetic recording devices), etc. Further, buffer rubber (crash stopper) for hard disk drives, binders for electrode active materials of nickel-metal hydride secondary batteries, binders for active materials of lithium-ion batteries, polymer electrolytes for lithium secondary batteries, binders for the positive electrodes of alkaline storage batteries, binders for EL elements (electroluminescence elements), binders for electrode active materials of capacitors, sealants, sealing agents, quartz coating materials for optical fibers, films and sheets such as optical fiber coating materials, CMOS electronic circuits, transistors, integrated circuits, organic transistors, light-emitting elements, actuators, memory, sensors, coils, capacitors, electronic components such as resistors, potting or coating or adhesive seal for circuit boards, fixing agents for electronic components, sealant modifiers such as epoxy, coating agents for printed circuit boards, modified materials for printed wiring board prepreg resins such as epoxy, shatterproof materials for light bulbs and the like, gaskets for computers, large computer cooling hoses, packing such as gaskets and O-rings for secondary batteries, sealing layers covering one or both sides of the outer surface of an organic EL structure, connectors, and dampers are also used.

[0136] In the field of chemical transport equipment, it can be used as a safety valve or shipping valve for trucks, trailers, tank trucks, ships, etc.

[0137] In the field of parts for mining equipment for exploring for and extracting energy resources such as oil and gas, they are used as various sealing materials used in the mining of oil, natural gas, etc., and as boots for electrical connectors used in oil wells.

[0138] Specific uses in the above-mentioned energy resource exploration and mining equipment parts field include drill bit seals, pressure adjustment diaphragms, seals for horizontal drilling motors (stators), stator bearing (shaft) seals, sealing materials used in blowout preventers (BOP), sealing materials used in rotary blowout preventers (pipe wipers), sealing materials and gas-liquid connectors used in MWD (real-time drilling information detection systems), logging tool seals (for example, O-rings, seals, packing, gas-liquid connectors, boots, etc.) used in logging equipment, expansion packers, completion packers and packer seals used therein, seals, packing, and perforators used in cementing equipment. Examples of seals include seals used in drilling equipment, seals, packings and motor linings used in mud pumps, underground audiometer covers, U-cups, composition seating cups, rotary seals, laminated elastomeric bearings, flow control seals, sand control seals, safety valve seals, seals for hydraulic fracturing equipment, seals and packings for linear packers and linear hangers, wellhead seals and packings, seals and packings for chokes and valves, sealing materials for LWD (logging while drilling), diaphragms used in oil exploration and oil drilling applications (for example, diaphragms for supplying lubricating oil to oil drilling pits), gate valves, electronic boots, and sealing elements for drilling guns.

[0139] Other applications include joint seals for kitchens, bathrooms, washrooms, etc.; cover cloths for outdoor tents; seals for printing materials; rubber hoses for gas heat pumps, fluorocarbon-resistant rubber hoses; agricultural films, linings, and weather-resistant covers; and tanks made of laminated steel sheets used in the construction and home appliance fields.

[0140] Furthermore, it can also be used as an article bonded to a metal such as aluminum, etc. Examples of such uses include door seals, gate valves, pendulum valves, solenoid tips, as well as metal-rubber parts bonded to metals such as piston seals, diaphragms, and metal gaskets.

[0141] It can also be used for rubber parts, brake shoes, brake pads, etc. in bicycles.

[0142] The molded article can also be applied to belts.

[0143] Examples of belts include the following: power transmission belts (including flat belts, V-belts, V-ribbed belts, toothed belts, etc.), flat belts used as conveyor belts in various high-temperature locations such as around the engines of agricultural machinery, machine tools, industrial machinery, etc.; conveyor belts for transporting loose or granular materials such as coal, crushed stone, soil and sand, ore, and wood chips in high-temperature environments; conveyor belts used in steelworks such as blast furnaces; conveyor belts for applications exposed to high-temperature environments in precision equipment assembly factories, food factories, etc.; V-belts and V-ribbed belts for agricultural machinery, general equipment (for example, office automation equipment, printing machines, commercial dryers, etc.), automobiles, etc.; transmission belts for transport robots; toothed belts such as transmission belts for food machinery and machine tools; toothed belts for use in automobiles, office automation equipment, medical applications, printing machines, etc.

[0144] In particular, timing belts are typical toothed belts for automobiles.

[0145] The belt may have a single layer structure or a multi-layer structure.

[0146] In the case of a multi-layer structure, the belt may be composed of a layer obtained by crosslinking a fluororubber composition and a layer composed of another material.

[0147] In the multi-layer belt, the layers made of other materials include layers made of other rubbers, layers made of thermoplastic resins, various fiber reinforcement layers, canvas, and metal foil layers.

[0148] The molded products can also be used for industrial vibration-damping pads, vibration-damping mats, railway slab mats, pads, automotive vibration-damping rubber, etc. Automotive vibration-damping rubber includes vibration-damping rubber for engine mounts, motor mounts, member mounts, strut mounts, bushings, dampers, muffler hangers, center bearings, etc.

[0149] Other applications include joint members such as flexible joints and expansion joints, boots, grommets, etc. In the marine field, for example, marine pumps can be mentioned.

[0150] Joint components are fittings used in piping and piping equipment, and are used for purposes such as preventing vibrations and noise generated by piping systems, absorbing expansion and contraction and displacement caused by temperature and pressure changes, absorbing dimensional fluctuations, and mitigating and preventing the effects of earthquakes and land subsidence.

[0151] Flexible joints and expansion joints can be preferably used as complex-shaped molded articles for, for example, shipbuilding piping, mechanical piping such as pumps and compressors, chemical plant piping, electrical piping, civil engineering and water supply piping, automobiles, etc. Boots can be preferably used as complex-shaped molded articles for, for example, automobile boots such as constant velocity joint boots, dust covers, rack and pinion steering boots, pin boots, and piston boots, as well as various industrial boots such as boots for agricultural machinery, boots for industrial vehicles, boots for construction machinery, boots for hydraulic machinery, boots for pneumatic machinery, boots for centralized lubrication systems, boots for liquid transfer, boots for firefighting, and boots for transferring various liquefied gases.

[0152] The molded articles can also be used as diaphragms for filter presses, blowers, water supply diaphragms, liquid storage tanks, pressure switches, accumulators, and air springs for suspensions, etc.

[0153] By adding the molded article to rubber or resin, an anti-slip agent can be obtained that provides molded articles or coating films that are non-slip in wet environments such as rain, snow, ice, and sweat.

[0154] The molded article can also be used as a cushioning material for hot press molding when producing decorative plywood, printed circuit boards, electrical insulating boards, rigid polyvinyl chloride laminates, etc., using melamine resin, phenolic resin, epoxy resin, etc.

[0155] The molded articles can also contribute to the impermeability of various substrates, such as sealing gaskets for weapons applications and protective clothing against contact with aggressive chemical agents.

[0156] The compound can also be used in various sealing materials, such as O-rings, V-rings, X-rings, packings, gaskets, diaphragms, oil seals, bearing seals, lip seals, plunger seals, door seals, lip and face seals, gas delivery plate seals, wafer support seals, barrel seals, and other sealing materials used to seal lubricating oils (engine oils, transmission oils, gear oils, etc.) containing amine additives (particularly amine additives used as antioxidants and detergents / dispersants) used in transportation such as automobiles and ships, as well as tubes, hoses, various rubber rolls, coatings, belts, valve bodies, etc. The compound can also be used as a laminating material and a lining material.

[0157] The coating material can be used as a heat-resistant and oil-resistant wire coating material for lead wires of sensors that come into contact with transmission oil and / or engine oil in internal combustion engines of automobiles, etc. to detect the oil temperature and / or oil pressure, and can also be used in high-temperature oil atmospheres such as the oil pans of automatic transmissions and engines.

[0158] In addition, vulcanized coatings may be formed on molded products for use in applications such as non-stick, oil-resistant rolls for copying machines, weather-resistant and anti-icing weather strips, rubber stoppers for infusions, rubber vial stoppers, mold release agents, non-stick lightweight conveyor belts, anti-stick coatings for car engine mount gaskets, coatings for synthetic fibers, and bolt members or joints with thin packing coating layers.

[0159] The use of molded products for automobile-related parts also includes use in motorcycle parts with similar structures.

[0160] Furthermore, examples of the automobile-related fuel include light oil, gasoline, and diesel engine fuel (including biodiesel fuel).

[0161] The molded article can also be used as a sealing member for a rolling bearing.

[0162] Examples of the rolling bearing include a ball bearing, a roller bearing, a bearing unit, and a linear bearing.

[0163] Examples of the ball bearing include a radial ball bearing, a thrust ball bearing, and a thrust angular ball bearing.

[0164] Examples of the radial ball bearing include deep groove ball bearings, angular contact ball bearings, four-point contact ball bearings, and self-aligning ball bearings.

[0165] The deep groove ball bearing is used, for example, in electric motors, household electrical appliances, office automation equipment, and the like.

[0166] Examples of angular contact ball bearings include single-row angular contact ball bearings, duplex angular contact ball bearings, and double-row angular contact ball bearings. Single-row angular contact ball bearings are used in electric motors, household electrical appliances, office automation equipment, etc., as well as hydraulic pumps and vertical pumps that are subject to axial loads in addition to radial loads. Duplex angular contact ball bearings are used in machine tool main shafts and grinding spindles that require improved shaft rotation accuracy and rigidity. Double-row angular contact ball bearings are used in electromagnetic clutches for automobile air conditioners, etc.

[0167] The four-point contact ball bearing is used in reducers and the like, where axial loads are applied from both directions and the width of the bearing cannot be made large.

[0168] The self-aligning ball bearing is used in places where it is difficult to align the shaft with the housing, or for transmission shafts where the shaft is prone to deflection.

[0169] The thrust ball bearings include single-direction thrust ball bearings and double-direction thrust ball bearings, and are applicable to the conventionally known uses for these ball bearings.

[0170] The above-mentioned thrust angular contact ball bearing is used in combination with a double-row cylindrical roller bearing to support the axial load of the main shaft of a machine tool.

[0171] Examples of the roller bearing include a radial roller bearing and a thrust roller bearing.

[0172] Examples of the radial roller bearing include cylindrical roller bearings, needle roller bearings, tapered roller bearings, and self-aligning roller bearings.

[0173] The cylindrical roller bearings are used in general machinery, machine tools, electric motors, reducers, railway axles, aircraft, etc.

[0174] Needle roller bearings are used in general machinery, automobiles, electric motors, etc.

[0175] Tapered roller bearings are used in machine tools, automotive and railway axles, rolling mills, reducers, etc.

[0176] Spherical roller bearings are used in general machinery, rolling mills, papermaking machines, axles, etc.

[0177] Examples of the thrust roller bearing include a thrust cylindrical roller bearing, a thrust needle roller bearing, a thrust tapered roller bearing, and a thrust spherical roller bearing.

[0178] Thrust cylindrical roller bearings are used in machine tools, general machinery, etc.

[0179] Thrust needle roller bearings are used in automobiles, pumps, general machinery, etc.

[0180] Thrust tapered roller bearings are used in general machinery, rolling mills, etc.

[0181] Spherical thrust roller bearings are used in cranes, extruders, general machinery, etc.

[0182] The fluororubber composition can be used as various parts in various industrial fields in addition to being used as a molded article after crosslinking. Next, the uses of the fluororubber composition will be described.

[0183] The fluororubber composition can be used as a surface modifier for metals, rubber, plastics, glass, etc.; sealing materials and coating materials that require heat resistance, chemical resistance, oil resistance, and non-stickiness, such as metal gaskets and oil seals; non-stick coating materials or bleed barriers for rolls for office equipment, belts for office equipment, etc.; and coating by impregnation or baking onto woven fabric sheets and belts.

[0184] The fluororubber composition can be used as a sealing material, lining or sealant having a complex shape by ordinary methods by making it highly viscous and highly concentrated, can be used to form a thin film of several microns by making it low viscosity, and can be used to apply pre-coated metal, O-rings, diaphragms or reed valves by making it medium viscosity.

[0185] Furthermore, it can also be used to coat transport rolls or belts for woven fabrics or paper sheets, printing belts, chemical-resistant tubes, chemical stoppers, fuel hoses, etc.

[0186] Examples of substrates that can be coated with the fluororubber composition include metals such as iron, stainless steel, copper, aluminum, and brass; glass products such as glass plates and woven and nonwoven fabrics of glass fibers; molded articles and coated products made of general-purpose and heat-resistant resins such as polypropylene, polyoxymethylene, polyimide, polyamideimide, polysulfone, polyethersulfone, and polyetheretherketone; molded articles and coated products made of general-purpose rubbers such as SBR, butyl rubber, NBR, and EPDM, and heat-resistant rubbers such as silicone rubber and fluororubber; and woven and nonwoven fabrics made of natural and synthetic fibers.

[0187] Coatings formed from the fluororubber composition can be used in fields where heat resistance, solvent resistance, lubricity, and non-stickiness are required, and specific applications include rolls (for example, fixing rolls and pressure rolls) and conveyor belts for office automation equipment such as copiers, printers, and facsimiles; sheets and belts; O-rings, diaphragms, chemical-resistant tubes, fuel hoses, valve seals, gaskets for chemical plants, and engine gaskets.

[0188] The fluororubber composition can also be dissolved in a solvent and used as a paint or adhesive, or can be used as a paint in the form of an emulsion dispersion (latex).

[0189] The fluororubber composition is used as a sealing material or lining for various devices, piping, etc., and as a surface treatment agent for structures made of inorganic or organic substrates such as metals, ceramics, glass, stone, concrete, plastics, rubber, wood, paper, and fiber.

[0190] The fluororubber composition can be applied to a substrate or the like by dispenser coating or screen printing coating.

[0191] The fluoroelastomer composition may be used as a coating composition for casting a film or for dipping a substrate such as fabric, plastic, metal, or elastomer.

[0192] In particular, the fluororubber composition, in the form of a latex, may be used to produce coated fabrics, protective gloves, impregnated fibers, O-ring coatings, coatings for fuel system quick connect O-rings, coatings for fuel system seals, coatings for fuel tank rollover valve diaphragms, coatings for fuel tank pressure sensor diaphragms, coatings for oil filters and fuel filter seals, coatings for fuel tank sender seals and sender head fitting seals, coatings for copier fuser rolls, and polymer coating compositions.

[0193] They are useful for coating silicone rubber, nitrile rubber, and other elastomers. They are also useful for coating parts made from such elastomers to enhance both the permeation resistance and chemical resistance of the substrate elastomer as well as its thermal stability. Other applications include coatings for heat exchangers, expansion joints, vats, tanks, fans, flue ducts and other ductwork, and containment structures, such as concrete containment structures. Fluoroelastomer compositions may also be applied to exposed cross sections of multilayer component structures, for example, in hose construction and diaphragm manufacturing processes. Sealing members in connections and joints are often composed of hard materials, and fluoroelastomer compositions provide improved frictional interfaces, enhanced dimensional interference fits with reduced leakage along the sealing surfaces. The latex enhances seal durability in various automotive system applications.

[0194] They can also be used in the manufacture of power steering systems, fuel systems, air conditioning systems, and any joints where hoses and tubes are connected to another component. Another useful application of fluoroelastomer compositions is in repairing manufacturing defects (and damage caused by use) in multi-layer rubber structures, such as three-layer fuel hoses. Fluoroelastomer compositions are also useful for coating thin steel sheets, which can be formed or embossed before or after paint is applied. For example, multiple layers of coated steel can be assembled to create a gasket between two rigid metal components. A sealing effect is achieved by applying a fluoroelastomer composition between the layers. This process can be used to manufacture engine head gaskets and exhaust manifold gaskets, reducing bolt forces and strain on the assembled components while providing better fuel economy and lower emissions due to low cracking, deflection, and hole distortion.

[0195] The fluororubber composition can also be used as a coating agent; a substrate-integrated gasket or packing formed by dispenser molding on a substrate containing an inorganic material such as a metal or ceramic; or a multi-layer product formed by coating on a substrate containing an inorganic material such as a metal or ceramic.

[0196] The fluororubber composition is also suitable as a wiring material for lightweight, flexible electronic devices and can be used in known electronic components. Examples of such electronic components include CMOS electronic circuits, transistors, integrated circuits, organic transistors, light-emitting elements, actuators, memories, sensors, coils, capacitors, and resistors. By using the fluororubber composition, flexible electronic devices such as solar cells, various displays, sensors, actuators, electronic artificial skin, sheet-type scanners, Braille displays, and wireless power transmission sheets can be obtained.

[0197] Although the embodiments have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the claims.

[0198] <1> According to a first aspect of the present disclosure, there is provided a fluororubber composition comprising a fluororubber (a), a crosslinking agent (b), and an organic acid (c), wherein the organic acid (c) is at least one selected from the group consisting of organic acids having 3 to 10 carbon atoms and having one acid group in the molecule, and organic acids having 2 to 10 carbon atoms and having two or more acid groups in the molecule. <2> According to a second aspect of the present disclosure, there is provided a fluororubber composition according to the first aspect, wherein the organic acid (c) is at least one selected from the group consisting of citric acid, phthalic acid, benzoic acid, adipic acid, and oxalic acid. <3> According to a third aspect of the present disclosure, there is provided a fluororubber composition according to the first or second aspect, wherein the crosslinking agent (b) is at least one selected from the group consisting of compounds represented by general formulas (b1) to (b6): General Formula (b1): (wherein x is an integer of 1 or more, and a hydrogen atom bonded to the benzene ring may be substituted with a hydrocarbon group, a halogen atom, an alkoxy group, an alkoxycarbonyl group, or an acyl group.) General formula (b2): (In the formula, a hydrogen atom bonded to the benzene ring may be substituted with a hydrocarbon group, a halogen atom, an alkoxy group, an alkoxycarbonyl group, or an acyl group.) General formula (b3): (In the formula, a hydrogen atom bonded to the benzene ring may be substituted with a hydrocarbon group, a halogen atom, an alkoxy group, an alkoxycarbonyl group, or an acyl group.) General formula (b4): (In the formula, a hydrogen atom bonded to the benzene ring may be substituted with a hydrocarbon group, a halogen atom, an alkoxy group, an alkoxycarbonyl group, or an acyl group.) General formula (b5): (In the formula, a hydrogen atom bonded to the benzene ring may be substituted with a hydrocarbon group, a halogen atom, an alkoxy group, an alkoxycarbonyl group, or an acyl group.) General formula (b6): (wherein the hydrogen atoms bonded to the benzene ring may be substituted by a hydrocarbon group, a halogen atom, an alkoxy group, an alkoxycarbonyl group, or an acyl group.) <4> According to a fourth aspect of the present disclosure, there is provided a fluororubber composition according to any one of the first to third aspects, wherein the crosslinking agent (b) is at least one selected from the group consisting of 1,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, methyl 3,5-dihydroxybenzoate, 3',5'-dihydroxyacetophenone, 4,4'-thiodiphenol, 4,4'-dihydroxydiphenyl ether, resorcinol, and 4-chlororesorcinol. <5> According to a fifth aspect of the present disclosure, there is provided a fluororubber composition according to any one of the first to third aspects, wherein the crosslinking agent (b) is at least one selected from the group consisting of 1,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, methyl 3,5-dihydroxybenzoate, 3',5'-dihydroxyacetophenone, 4,4'-thiodiphenol, 4,4'-dihydroxydiphenyl ether, resorcinol, and 4-chlororesorcinol. Ａ ) is the crosslink induction time (T10 Ｂ<6> According to a sixth aspect of the present disclosure, there is provided a fluororubber composition according to any one of the first to fifth aspects, further comprising a crosslinking accelerator (d). <7> According to a seventh aspect of the present disclosure, there is provided a fluororubber composition according to any one of the first to sixth aspects, further comprising an acid acceptor (e). <8> According to an eighth aspect of the present disclosure, the fluororubber (a) is a fluororubber containing vinylidene fluoride units, the crosslinking agent (b) is a polyol crosslinking agent, the organic acid (c) is at least one selected from the group consisting of citric acid, phthalic acid, benzoic acid, and adipic acid, and further contains a crosslinking accelerator (d) and an acid acceptor (e), the crosslinking accelerator (d) is a quaternary ammonium salt, and the acid acceptor (e) is at least one selected from the group consisting of a metal oxide, a metal hydroxide, an alkali metal silicate, a metal salt of a weak acid, and hydrotalcite, the content of the crosslinking agent (b) is 0.1 to 10 parts by mass relative to 100 parts by mass of the fluororubber, the content of the organic acid (c) is 0.05 to 10 parts by mass relative to 100 parts by mass of the fluororubber, and the content of the crosslinking accelerator (d) is 0.1 to 10 parts by mass relative to 100 parts by mass of the fluororubber, According to a ninth aspect of the present disclosure, there is provided a molded article obtained from the fluororubber composition according to any one of the first to eighth aspects, wherein the content of the acid acceptor (e) is 0.1 to 20 parts by mass relative to 100 parts by mass of the fluororubber. <9> According to a ninth aspect of the present disclosure, there is provided a molded article obtained from the fluororubber composition according to any one of the first to eighth aspects.

[0199] Next, embodiments of the present disclosure will be described with reference to examples, but the present disclosure is not limited to these examples.

[0200] The values ​​in the examples were measured by the following methods.

[0201] <Monomer composition of fluororubber> １９ Measurement was carried out using F-NMR (Bruker AC300P model).

[0202] <Fluorine content> １９The content was calculated from the composition of the fluororubber measured by F-NMR.

[0203] <Mooney Viscosity> Measured in accordance with ASTM D1646-15 and JIS K6300-1:2013 at a measurement temperature of 121°C.

[0204] <Glass Transition Temperature (Tg)> A DSC curve was obtained by heating 10 mg of a sample at a rate of 20°C / min using a differential scanning calorimeter (DSC822e manufactured by Mettler Toledo or X-DSC7000 manufactured by Hitachi High-Tech Science Corporation), and the glass transition temperature was determined as the temperature at the intersection of an extension of the baseline before and after the second-order transition of the DSC curve and a tangent to the inflection point of the DSC curve.

[0205] <Heat of Fusion> A differential scanning calorimeter (DSC822e, manufactured by Mettler Toledo, or X-DSC7000, manufactured by Hitachi High-Tech Science) was used to obtain a DSC curve by heating 10 mg of a sample at a rate of 20°C / min, and the heat of fusion was calculated from the magnitude of the melting peak (ΔH) that appeared in the DSC curve.

[0206] <Number of Acid Groups of Organic Acid N> The number of acid groups of organic acid N (×10 －２ The number of cells was calculated according to the following formula: N (×10 －２ (number of acid groups per molecule of organic acid) = (amount of organic acid (parts by mass) per 100 parts by mass of rubber) / (molecular weight of organic acid) × (number of acid groups per molecule of organic acid) × 100

[0207] <Crosslinking characteristics> For the fluororubber composition, a crosslinking curve was determined at the temperatures shown in Table 1 during primary crosslinking using a vulcanization tester (MDR H2030 manufactured by M&K Co., Ltd.), and the minimum torque (ML), maximum torque (MH), crosslinking induction time (T10), and optimum crosslinking time (T90) were determined from the change in torque.

[0208] <(T10 Ａ ) / (T10 Ｂ )> Crosslinking induction time (T10) of Comparative Example 1 Ｂ ) to the crosslinking induction time (T10 Ａ ) ratio ((T10 Ａ ) / (T10 Ｂ The ratio ((T10Ａ ) / (T10 Ｂ )) is the crosslinking induction time (T10 Ａ ) of the fluororubber composition (B) containing the same components as the fluororubber composition (A) except that it does not contain an organic acid, Ｂ Similarly, the crosslinking induction time (T10 Ｂ ) to the crosslinking induction time (T10 Ａ ) ratio ((T10 Ａ ) / (T10 Ｂ ) were calculated respectively.

[0209] <100% Modulus, Tensile Strength, and Elongation at Break> A 2 mm thick crosslinked sheet was used to prepare a No. 6 dumbbell shaped test piece. Using the obtained test piece and a tensile testing machine (Tensilon RTG-1310 manufactured by A&D Co., Ltd.), the 100% modulus (M100), tensile strength (TB), and elongation at break (EB) were measured at 23°C under conditions of 500 mm / min in accordance with JIS K6251:2010.

[0210] <Hardness (HS peak)> Three crosslinked sheets each having a thickness of 2 mm were stacked, and the durometer hardness (type A, peak value) was measured in accordance with JIS K6251-3:2012.

[0211] <Compression set (CS)> Using a small test piece for measuring compression set, measurement was carried out in accordance with Method A of JIS K6262:2013, at a compression ratio of 25%, a test temperature of 200°C, and a test time of 72 hours.

[0212] In the examples and comparative examples, the following materials were used.

[0213] Fluorine rubber Vinylidene fluoride / hexafluoropropylene molar ratio: 78 / 22 Fluorine content: 66% Mooney viscosity (ML1+10 (121°C)): 43 Glass transition temperature: -18°C Heat of fusion: Not observed in the second run

[0214] Crosslinking agent Methyl 3,5-dihydroxybenzoate 4,4'-thiodiphenol 4,4'-dihydroxydiphenyl ether Resorcinol 4-chlororesorcinol

[0215] Crosslinking accelerator: 8-benzyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride (DBU-B)

[0216] Carbon black: Trade name "Thermax N990", manufactured by Cancarb Co. Magnesium oxide: Trade name "Kyowamag 150", manufactured by Kyowa Chemical Industry Co., Ltd. Calcium hydroxide: Trade name "NICC5000", manufactured by Inoue Lime Industry Co., Ltd.

[0217] Examples 1 to 9 and Comparative Examples 1 to 7 Fluororubber compositions were prepared by blending the components according to the formulations in Table 1 and kneading them on an open roll. The crosslinking properties of the resulting fluororubber compositions are shown in Table 1. The fluororubber compositions were then crosslinked by primary crosslinking (press crosslinking) under the conditions shown in Table 1 and secondary crosslinking (oven crosslinking) under the conditions shown in Table 1, to obtain crosslinked sheets (2 mm thick) and small test pieces for measuring compression set. The evaluation results of the resulting crosslinked sheets and the results of the compression set test are shown in Table 1.

[0218] In Table 1, the number "1" in the column for the experimental example number represents "Example 1," and the numbers "2" to "9" represent "Example 2" to "Example 9," respectively. Furthermore, the number "C1" in the column for the experimental example number represents "Comparative Example 1," and the numbers "C2" to "C7" represent "Comparative Example 2" to "Comparative Example 7," respectively.

[0219]

[0220] The results shown in Table 1 show that the fluororubber compositions (Examples 1 to 3) containing specific organic acids exhibit crosslink induction times (T10) that are 1.2 times longer than the fluororubber composition (Comparative Example 1) containing the same components as the fluororubber compositions (Examples 1 to 3) except for not containing an organic acid. Moreover, the fluororubber compositions (Examples 1 to 3) exhibit maximum torques (MH) equivalent to that of the fluororubber composition (Comparative Example 1), indicating that they can be crosslinked to approximately the same degree of crosslinking as the fluororubber composition (Comparative Example 1).

[0221] Similarly, it can be seen that the fluororubber compositions (Examples 4 to 9) containing specific organic acids each exhibit a crosslink induction time (T10) that is 1.2 times or more longer than the fluororubber compositions (Comparative Examples 2 to 7) containing the same components as the fluororubber compositions (Examples 4 to 9) except for not containing an organic acid. Moreover, the fluororubber compositions (Examples 4 to 9) exhibit a maximum torque (MH) equivalent to that of the fluororubber compositions (Comparative Examples 2 to 7), which shows that they can be crosslinked to approximately the same degree of crosslinking as the fluororubber compositions (Comparative Examples 2 to 7).

Claims

1. A fluororubber composition comprising a fluororubber (a), a crosslinking agent (b) and an organic acid (c), wherein the organic acid (c) is at least one selected from the group consisting of organic acids having 3 to 10 carbon atoms and having one acid group in the molecule, and organic acids having 2 to 10 carbon atoms and having two or more acid groups in the molecule.

2. The fluororubber composition according to claim 1, wherein the organic acid (c) is at least one selected from the group consisting of citric acid, phthalic acid, benzoic acid, adipic acid and oxalic acid.

3. The fluororubber composition according to claim 1 or 2, wherein the crosslinking agent (b) is at least one selected from the group consisting of compounds represented by general formulas (b1) to (b6). General formula (b1): (wherein x is an integer of 1 or more, and a hydrogen atom bonded to the benzene ring may be substituted with a hydrocarbon group, a halogen atom, an alkoxy group, an alkoxycarbonyl group or an acyl group.) General formula (b2): (In the formula, a hydrogen atom bonded to the benzene ring may be substituted with a hydrocarbon group, a halogen atom, an alkoxy group, an alkoxycarbonyl group, or an acyl group.) General formula (b3): (In the formula, a hydrogen atom bonded to the benzene ring may be substituted with a hydrocarbon group, a halogen atom, an alkoxy group, an alkoxycarbonyl group, or an acyl group.) General formula (b4): (In the formula, a hydrogen atom bonded to the benzene ring may be substituted with a hydrocarbon group, a halogen atom, an alkoxy group, an alkoxycarbonyl group, or an acyl group.) General formula (b5): (In the formula, a hydrogen atom bonded to the benzene ring may be substituted with a hydrocarbon group, a halogen atom, an alkoxy group, an alkoxycarbonyl group, or an acyl group.) General formula (b6): (In the formula, a hydrogen atom bonded to the benzene ring may be substituted with a hydrocarbon group, a halogen atom, an alkoxy group, an alkoxycarbonyl group, or an acyl group.) 4. The fluororubber composition according to any one of claims 1 to 3, wherein the crosslinking agent (b) is at least one selected from the group consisting of 1,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 3,5-methyl dihydroxybenzoate, 3',5'-dihydroxyacetophenone, 4,4'-thiodiphenol, 4,4'-dihydroxydiphenyl ether, resorcinol, and 4-chlororesorcinol.

5. Crosslink induction time (T10) of fluororubber composition (A) containing organic acid (c) Ａ ) is the crosslink induction time (T10) of the fluororubber composition (B) containing the same components as the fluororubber composition (A) except that it does not contain the organic acid (c). Ｂ 5. The fluororubber composition according to claim 1, wherein the ratio of the total mass of the fluororubber to the total mass of the non-fluororubber is 1.2 times or more.

6. The fluororubber composition according to any one of claims 1 to 5, further comprising a crosslinking accelerator (d).

7. The fluororubber composition according to any one of claims 1 to 6, further comprising an acid acceptor (e).

8. A fluororubber (a) containing vinylidene fluoride units, the crosslinking agent (b) being a polyol crosslinking agent, the organic acid (c) being at least one selected from the group consisting of citric acid, phthalic acid, benzoic acid and adipic acid, and further containing a crosslinking accelerator (d) and an acid acceptor (e), the crosslinking accelerator (d) being a quaternary ammonium salt, the acid acceptor (e) being at least one selected from the group consisting of metal oxides, metal hydroxides, alkali metal silicates, metal salts of weak acids and hydrotalcites, the content of the crosslinking agent (b) being 0.1 to 10 parts by mass relative to 100 parts by mass of the fluororubber, the content of the organic acid (c) being 0.05 to 10 parts by mass relative to 100 parts by mass of the fluororubber, and the content of the crosslinking accelerator (d) being 0.1 to 10 parts by mass relative to 100 parts by mass of the fluororubber, The fluororubber composition according to claim 1 or 2, wherein the content of the acid acceptor (e) is 0.1 to 20 parts by mass based on 100 parts by mass of the fluororubber.

9. A molded article obtained from the fluororubber composition according to any one of claims 1 to 8.

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