Composition for crosslinking fluororubber and molded article

Abstract

To provide a composition for crosslinking fluororubber capable of obtaining a molded article having a well-balanced combination of elongation and compression set characteristics at high temperature.SOLUTION: Provided is at least one kind of composition for crosslinking fluororubber selected from the group consisting of a compound (b1) that contains fluororubber (a) and a crosslinking agent (b), in which the crosslinking agent (b) has two or more aromatic rings, two or more hydroxy groups directly bonded to carbon atoms making up the aromatic rings, and one to six substituent groups (α) (however, excluding a bromine atom, an amino group, a sulfanyl group, an acid group and any group containing these groups) with at least either value of Hammett's substituent constants σm and σp being 0.03 or more, directly bonded to the carbon atoms making up the aromatic rings, and a salt of the compound (b1) with an alkali metal, an alkaline earth metal or an onium compound.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present disclosure relates to a composition for crosslinking a fluororubber and a molded article. [Background technology]

[0002] US Pat. No. 5,399,633 describes aromatic polyhydroxy compounds that can act as crosslinkers or co-curing agents for fluorinated elastomers as essential components in the final curable composition. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 64-418 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present disclosure is to provide a composition for crosslinking a fluororubber, which is capable of giving a molded article having a well-balanced combination of elongation and high-temperature compression set properties. [Means for solving the problem]

[0005] According to a first aspect of the present disclosure, there is provided a composition for crosslinking fluororubber, comprising a fluororubber (a) and a crosslinking agent (b), wherein the crosslinking agent (b) is at least one selected from the group consisting of a compound (b1) having two or more aromatic rings, two or more hydroxy groups bonded directly to carbon atoms constituting the aromatic rings, and one or more Hammett substituent constants σm and σp of 0.03 or more and having 1 to 6 substituents (α) (excluding bromine atoms, amino groups, sulfanyl groups, acid groups, and groups containing these groups) bonded directly to carbon atoms constituting the aromatic rings, and a salt of the compound (b1) with an alkali metal, an alkaline earth metal, or an onium compound. Effect of the Invention

[0006] According to the present disclosure, it is possible to provide a fluororubber cross-linking composition capable of giving a molded article having a well-balanced combination of elongation and high-temperature compression set properties. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[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] The composition for crosslinking a fluororubber of the present disclosure contains a fluororubber (a) and a crosslinking agent (b).

[0009] Patent Document 1 describes that, with respect to any known aromatic polyhydroxy compounds that can act as crosslinkers or auxiliary curing agents, one of the most useful aromatic polyphenols is the bisphenol compound hexafluoroisopropylidene-bis(4-hydroxybenzene), known as bisphenol AF.

[0010] It has been found that by using a specific compound as a crosslinking agent, it is possible to obtain a molded product having a good balance of elongation and high-temperature compression set properties compared to the case of using a conventional crosslinking agent such as bisphenol AF. The fluororubber crosslinking composition of the present disclosure is a composition that has been completed based on such new findings.

[0011] Hereinafter, each component of the fluororubber crosslinking composition of the present disclosure will be described.

[0012] (a) Fluorine rubber The fluororubber used in this disclosure is preferably a polyol-crosslinkable fluororubber. The polyol-crosslinkable fluororubber is a fluororubber having a polyol-crosslinkable site. In this disclosure, the fluororubber is an amorphous fluoropolymer. "Amorphous" means that the magnitude of the melting peak (ΔH) that appears in the 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. The fluororubber exhibits elastomeric properties by crosslinking. Elastomeric properties refer to the property that the polymer can be stretched and can retain its original length when the force required to stretch the polymer is no longer applied.

[0013] Examples of the polyol crosslinkable portion include a portion having a vinylidene fluoride (VdF) unit, etc. Among these, a fluororubber containing a VdF unit is preferred because the effect of using the crosslinking agent (b) is easily exhibited.

[0014] Examples of fluororubbers having a polyol crosslinkable site include non-perfluoro fluororubbers and fluororubbers containing -CH2- (methylene group) in the main chain. Examples of fluororubbers having a polyol crosslinkable site include A vinylidene fluoride (VDF)-based fluoroelastomer having substantially no polar terminal group, as described in JP-A-2003-277563; A vinylidene fluoride-based fluoroelastomer comprising repeating units derived from vinylidene fluoride (VDF) and repeating units derived from at least one additional (per)fluorinated monomer as described in JP2018-527449A; 100 parts (phr) of a cured fluoroelastomer having a small amount of fluorine of less than 67% by weight as described in JP-A-7-316377, containing 40 to 68% by weight of vinylidene fluoride (VDF) units and 20 to 50% by weight of hexafluoropropylene (HFP) units, totaling 100, and optionally containing one or more comonomers having ethylene unsaturation. etc.

[0015] Examples of fluororubbers having a polyol crosslinkable site include VdF-based fluororubbers, rubbers having a polyol crosslinkable functional site in the side chain and / or main chain, etc. Examples of 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 having a polyol crosslinkable site can be used alone or in any combination within the scope that does not impair the effects of the present disclosure.

[0016] The VdF-based fluororubber is preferably one represented by the following general formula (1).

[0017] -(M 1 )-(M 2 )-(N 1 )- (1) (Wherein, structural unit M 1 is vinylidene fluoride (m 1 ) structural unit derived from the structural unit M 2 is a fluorine-containing ethylenic monomer (m 2 ) 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

[0018] In the VdF-based fluororubber represented by the general formula (1), the structural unit M 1 30 to 85 mol % of structural unit M 2 It is preferable that the structural unit M 1 50 to 80 mol % of 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.

[0019] As the fluorine-containing ethylenic monomer (m 2 ), one or more monomers can be used. For example, TFE, chlorotrifluoroethylene (CTFE), trifluoroethylene, HFP, trifluoropropylene, tetrafluoropropylene, pentafluoropropylene, trifluorobutene, tetrafluoroisobutene, perfluoro(alkyl vinyl ether) (PAVE), general formula (2): CF2=CFO(Rf 1 O) q (Rf 2 O) r Rf 3 (2) (In the formula, Rf 1 and Rf 2 are each independently 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, q and r are each independently an integer from 0 to 6 (provided that 0 < q + r ≤ 6)), a fluorine-containing monomer represented by general formula (3): CHX 11 =CX 12 Rf 4 (3) (In the formula, X 11 and X 12 are such that one is H and the other is F, and Rf 4 is a linear or branched fluoroalkyl group having 1 to 12 carbon atoms), and fluorine-containing monomers such as vinyl fluoride can be mentioned. Among these, TFE, HFP, and PAVE are preferred.

[0020] As the monomer (n 1 ), any monomer can be used as long as it is copolymerizable with the monomer (m 1 ) and the monomer (m 2 ). For example, ethylene, propylene, alkyl vinyl ether, a monomer providing a crosslinking site, a bisolefin compound, etc. can be mentioned. These can be used alone or in any combination.

[0021] Examples of monomers that provide such crosslinking sites include those represented by the general formula (4): C.Y. 1 2=CY 1 -Rf 5 CHR 1 X 41 (4) (In the formula, Y 1 are independently a hydrogen atom, a fluorine atom or -CH3, Rf 5 represents a fluoroalkylene group, a perfluoroalkylene group, a fluoropolyoxyalkylene group or a perfluoropolyoxyalkylene group; R 1 is a hydrogen atom or -CH3, X 41 is an iodine atom or a bromine atom), an iodine- or bromine-containing monomer represented by the general formula (5): CF2 = CFO(CF2CF(CF3)O) m (CF2) n -X 51 (5) (In the formula, m is an integer of 0 to 5, n is an integer of 1 to 3, X 51 is a cyano group, a carboxyl group, an alkoxycarbonyl group, a bromine atom, or an iodine atom), a monomer represented by the general formula (6): CH2=CH(CF2) 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 iodine-containing monomers such as CF2=CFOCF2CF2CH2I as described in JP-A-4-217936 are included. Examples of suitable monomers include iodine-containing monomers, such as 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, cyano group-containing monomers, carboxyl group-containing monomers, and alkoxycarbonyl group-containing monomers described in JP-A-4-505345 and JP-A-5-500070, etc. These may be used alone or in any combination. As the bisolefin compound, those described in JP-A-8-12726 can be used.

[0022] 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.

[0023] Examples of rubbers having functional sites capable of being crosslinked with polyols in the side chain and / or main chain include tetrafluoroethylene (TFE) / perfluoro(alkyl vinyl ether) (PAVE) / R, described in JP-A-60-44511 or JP-A-3890630. 1 CH=CR 2 R 3 (R in the formula 1 and R 2 are independently selected from hydrogen and fluorine, and R 3 are independently selected from hydrogen, fluorine, alkyl, and perfluoroalkyl), and rubbers having double bonds in the side chains and / or main chain.

[0024] Among these, the fluororubber is preferably a fluororubber made 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 fluororubber, VdF / TFE / HFP-based fluororubber, and VdF / TFE / PAVE-based fluororubber, and more preferably at least one rubber selected from the group consisting of VdF / HFP-based fluororubber and VdF / TFE / HFP-based fluororubber.

[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. Also, it 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 mass%, more preferably 60 to 73 mass%, and further preferably 63 to 72 mass%. The fluorine content is 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 by heating 10 mg of a sample at 20° C. / min using a differential scanning calorimeter, and determining the glass transition temperature as the temperature indicating the intersection point 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 crosslinking composition of the present disclosure contains a crosslinking agent. In the present disclosure, a first crosslinking agent or a second crosslinking agent is used.

[0030] The first crosslinking agent used in the present disclosure is Compounds (b1) having two or more aromatic rings, two or more hydroxy groups bonded to the aromatic rings, and one to six substituents (α) (excluding bromine atoms, amino groups, sulfanyl groups, acid groups and groups containing these groups) bonded to the aromatic rings, with at least one of the Hammett substituent constants σm and σp being 0.03 or more, and A salt of compound (b1) with an alkali metal, an alkaline earth metal or an onium compound At least one selected from the group consisting of:

[0031] The second crosslinking agent used in the present disclosure is at least one selected from the group consisting of a compound (b1) having two or more aromatic rings, two or more hydroxy groups directly bonded to carbon atoms constituting the aromatic rings, and one to six substituents (α) (excluding bromine atoms, amino groups, sulfanyl groups, acid groups and groups containing these groups) directly bonded to carbon atoms constituting the aromatic rings, and a salt of the compound (b1) with an alkali metal, an alkaline earth metal or an onium compound, The solubility parameter (SP value) of compound (b1) calculated by the Fedors equation is 12.1 to 17.8 (cal / cm 3 ) 1 / 2 and In compound (b1), the distance between the oxygen atom of the hydroxy group and the carbon atom to which the hydroxy group is directly bonded (OC bond distance L) is 1.357 to 1.369 Å.

[0032] The substituent (α) does not include a bromine atom, an amino group, a sulfanyl group, an acid group, or a group containing these groups. The term "group containing these groups" refers to a group that contains a bromine atom, an amino group, a sulfanyl group, or an acid group as part of its structure.

[0033] An acid group is a group having a hydrogen atom that can be ionized as a proton. In the present disclosure, the acid group also includes an acid base in which the hydrogen atom is replaced by another atom (such as an alkali metal atom). An example of the acid group is an oxo acid group (a group having an atom to which a hydroxy group (-OH) and an oxo group (=O) are bonded, and in which the hydroxy group can release a proton). Typical examples of the acid group are a carboxy group, a sulfo group, a sulfino group, a phosphoric acid group, a phosphonic acid group, and the acid bases thereof.

[0034] In one embodiment, the substituent (α) of the compound (b1) is a monovalent substituent, and at least one of the Hammett substituent constants σm and σp is within a range of 0.03 or more. The substituent (α) is directly bonded to the aromatic ring of the compound (b1), and therefore affects the electron density of the hydroxy group bonded to the aromatic ring, and it is presumed that this action improves in a well-balanced manner the elongation and high-temperature compression set properties of the molded article obtained from the fluororubber crosslinking composition.

[0035] The total number of substituents (α) in compound (b1) is 1 to 6, preferably 2 to 4, more preferably 2 to 3, and further preferably 2. If the number of substituents (α) is too large, the crosslinking reaction does not proceed sufficiently, and a molded article having desired physical properties cannot be obtained.

[0036] The bonding position of the substituent (α) in the compound (b1) is not particularly limited, and it can be bonded to any carbon atom constituting the aromatic ring of the compound (b1), but it is preferable that the hydroxyl group of the compound (b1) is bonded to a position where the hydroxyl group has an appropriate electron density. It is more preferable that at least one hydroxyl group and at least one substituent (α) are directly bonded to at least two aromatic rings among the two or more aromatic rings of the compound (b1).

[0037] At least one of the substituent constants σm and σp of the substituent (α) is 0.03 or more, preferably 0.05 or more, more preferably 0.10 or more, preferably 1.40 or less, more preferably 1.00 or less, and even more preferably 0.80 or less. If both the substituent constants σm and σp of the substituent (α) are too small or too large, it becomes difficult to obtain a molded article having a good balance of elongation and high-temperature compression set properties.

[0038] In one embodiment, the value of the substituent constant σm of the substituent (α) is 0.03 or more, preferably 0.05 or more, more preferably 0.10 or more, preferably 1.40 or less, more preferably 1.00 or less, and even more preferably 0.80 or less.

[0039] In one embodiment, the value of the substituent constant σp of the substituent (α) is 0.03 or more, preferably 0.05 or more, more preferably 0.10 or more, preferably 1.40 or less, more preferably 1.00 or less, and even more preferably 0.80 or less.

[0040] When compound (b1) has one or more benzene rings as aromatic rings, it is preferred that at least one hydroxy group and one or more substituents (α) are directly bonded to at least one benzene ring.

[0041] When one or more hydroxy groups and one or more substituents (α) are directly bonded to at least one benzene ring and the substituent (α) has a substituent constant σm within the above range, it is preferred that the substituent (α) and the hydroxy group are bonded to the meta position of the benzene ring.

[0042] When one or more hydroxy groups and one or more substituents (α) are directly bonded to at least one benzene ring and the substituent (α) has a substituent constant σp within the above range, it is preferred that the substituent (α) and the hydroxy group are bonded to the ortho or meta position of the benzene ring.

[0043] When compound (b1) has, as an aromatic ring, at least one benzene ring to which one or more hydroxy groups and one or more substituents (α) are directly bonded, it is preferable that the at least one hydroxy group and the at least one substituent (α) bonded to the benzene ring satisfy any one of the following conditions: (H-1): The substituent constant σm of the substituent (α) is 0.03 or more, and the substituent (α) and a hydroxy group are bonded to the meta position of the benzene ring. (H-2): The substituent constant σp of the substituent (α) is 0.03 or more, and the substituent (α) and the hydroxyl group are bonded to the ortho position of the benzene ring. (H-3): The substituent constant σp of the substituent (α) is 0.03 or more, and the substituent (α) and the hydroxyl group are bonded to the para position of the benzene ring.

[0044] When the compound (b1) has two or more aromatic rings and at least one aromatic ring is a benzene ring, it is preferable that at least one hydroxyl group and at least one substituent (α) are directly bonded to at least one benzene ring. In this case, it is preferable that at least one hydroxyl group and at least one substituent (α) bonded to the benzene ring meet any of the conditions (H-1) to (H-3), and it is more preferable that at least one hydroxyl group and at least one substituent (α) bonded to the benzene ring meet the condition (H-1).

[0045] When the compound (b1) has two or more aromatic rings and at least two of the aromatic rings are benzene rings, it is preferred that at least one hydroxy group and at least one substituent (α) are directly bonded to the at least two benzene rings. In this case, among the at least two benzene rings, At least one hydroxy group and at least one substituent (α) bonded to each of the two benzene rings preferably satisfy any one of the conditions (H-1) to (H-3), It is more preferable that at least one hydroxy group and at least one substituent (α) bonded to one benzene ring meet the condition (H-1), and at least one hydroxy group and at least one substituent (α) bonded to another benzene ring different from the benzene ring meet any of the conditions (H-1) to (H-3), It is more preferable that at least one hydroxy group and at least one substituent (α) bonded to each of the two benzene rings satisfy condition (H-1).

[0046] When the compound (b1) has two aromatic rings, and both of the two aromatic rings are benzene rings, it is preferable that at least one hydroxy group and at least one substituent (α) are directly bonded to both of the two benzene rings. In this case, among the two benzene rings, At least one hydroxy group and at least one substituent (α) bonded to each of the two benzene rings preferably satisfy any one of the conditions (H-1) to (H-3), It is more preferable that at least one hydroxy group and at least one substituent (α) bonded to one benzene ring meet the condition (H-1), and at least one hydroxy group and at least one substituent (α) bonded to the other benzene ring meet any of the conditions (H-1) to (H-3), It is more preferable that at least one hydroxy group and at least one substituent (α) bonded to each of the two benzene rings satisfy condition (H-1).

[0047] Hammett's rule is an empirical rule proposed by LP Hammett in 1935 to quantitatively discuss the effect of a substituent on the reaction or equilibrium of a benzene derivative, and is now widely recognized as valid. The substituent constants determined by Hammett's rule include σp and σm values, and these values ​​can be found in many general textbooks. In the present invention, the values ​​described in "TABLE 1 Hammett and Modified Swain-Lupton Constants" in Chem.Rev., 1991, Vol. 91, pp. 165-195 are used. For substituents not described in the above literature, values ​​calculated according to the calculation method described in the literature "The Effect of Structure upon the Reactions of Organic Compounds. Benzene Derivatives" (J.Am.Chem.Soc.1937, 59, 1, 96-103) are used.

[0048] In addition, the compound (b1) also includes compounds that are not benzene derivatives, but the σm value and σp value are used as a measure of the electronic effect of the substituent, regardless of the substitution position. In this disclosure, the σm value and σp value are used in this sense.

[0049] Specific examples of the substituent (α) include a partially fluorinated alkyl group having 1 to 5 carbon atoms, a perfluoroalkyl group having 1 to 5 carbon atoms, a fluorine atom, a chlorine atom, an alkoxycarbonyl group having 1 to 5 carbon atoms (excluding the number of carbon atoms constituting the carbonyl group), a partially fluorinated alkoxycarbonyl group having 1 to 5 carbon atoms (excluding the number of carbon atoms constituting the carbonyl group), a perfluoroalkoxycarbonyl group having 1 to 5 carbon atoms (excluding the number of carbon atoms constituting the carbonyl group), an alkoxy group having 1 to 5 carbon atoms, a partially fluorinated alkoxy group having 1 to 5 carbon atoms, a perfluoroalkoxy group having 1 to 5 carbon atoms, an acyloxy group having 1 to 5 carbon atoms (excluding the number of carbon atoms constituting the carbonyl group), groups, acyloxy groups having 1 to 5 carbon atoms (excluding the number of carbon atoms constituting the carbonyl group) which are partially fluorinated, perfluoroacyloxy groups having 1 to 5 carbon atoms (excluding the number of carbon atoms constituting the carbonyl group), acyl groups having 0 to 5 carbon atoms (excluding the number of carbon atoms constituting the carbonyl group), acyl groups having 0 to 5 carbon atoms (excluding the number of carbon atoms constituting the carbonyl group) which are partially fluorinated, perfluoroacyl groups having 0 to 5 carbon atoms (excluding the number of carbon atoms constituting the carbonyl group), alkylsulfonyl groups having 1 to 5 carbon atoms, alkylsulfonyl groups having 1 to 5 carbon atoms which are partially fluorinated, perfluoroalkylsulfonyl groups having 1 to 5 carbon atoms, and trimethoxysilyl groups.

[0050] The substituent (α) is preferably at least one selected from the group consisting of a partially fluorinated alkyl group having 1 to 5 carbon atoms, a perfluoroalkyl group having 1 to 5 carbon atoms, a fluorine atom, a chlorine atom, an alkoxy group having 1 to 5 carbon atoms, an alkoxycarbonyl group having 0 to 5 carbon atoms (excluding the number of carbon atoms constituting the carbonyl group), an acyl group having 0 to 5 carbon atoms (excluding the number of carbon atoms constituting the carbonyl group), and an acyloxy group having 1 to 5 carbon atoms (excluding the number of carbon atoms constituting the carbonyl group). It is more preferable that the group is at least one selected from the group consisting of an alkoxycarbonyl group having 0 to 5 carbon atoms (excluding the number of carbon atoms constituting the carbonyl group) and an acyl group having 0 to 5 carbon atoms (excluding the number of carbon atoms constituting the carbonyl group), still more preferable that the group is at least one selected from the group consisting of a perfluoroalkyl group having 1 to 5 carbon atoms, a fluorine atom, a chlorine atom and an acyl group having 0 to 5 carbon atoms (excluding the number of carbon atoms constituting the carbonyl group), still more preferable that the group is at least one selected from the group consisting of a trifluoromethyl group, a fluorine atom, a chlorine atom and an acetyl group, and particularly preferable that the trifluoromethyl group, a fluorine atom and an acetyl group.

[0051] The hydrogen atoms bonded to the carbon atoms constituting the aromatic ring of compound (b1) may be substituted with any substituent other than the substituent (α) or may not be substituted. However, it is preferable that the hydrogen atoms are not substituted with any substituent other than the substituent (α) so as not to impair the function of the substituent (α) that provides the hydroxy group with an appropriate electron density.

[0052] The total number of hydroxy groups contained in the compound (b1) is 2 or more, preferably 2 to 4, more preferably 2 to 3, and further preferably 2.

[0053] In one embodiment, the solubility parameter (SP value) of the compound (b1) is 12.1 to 17.8 (cal / cm 3 ) 1 / 2and the O-C bond distance L of the compound (b1) is 1.357 to 1.369 Å.

[0054] The solubility parameter (SP value) is preferably 12.5 (cal / cm 3 ) 1 / 2 More preferably, it is 16.5 (cal / cm 3 ) 1 / 2 More preferably, it is 16.0 (cal / cm 3 ) 1 / 2 The following is the result.

[0055] The O-C bond distance L of the compound (b1) is 1.357 to 1.369 Å, preferably 1.361 Å or more, more preferably 1.363 Å or more, and preferably 1.368 Å or less, more preferably 1.367 Å or less.

[0056] When the solubility parameter (SP value) and the O-C bond distance L of the compound (b1) are both within the above-mentioned numerical ranges, the crosslinking reaction in the fluororubber crosslinking composition tends to proceed uniformly, and a molded product having a good balance of elongation and high-temperature compression set properties can be obtained.

[0057] The magnitude of the solubility parameter (SP value) of the compound (b1) affects the degree of dispersion of the crosslinking agent in the fluororubber crosslinking composition. Therefore, when the solubility parameter (SP value) of the compound (b1) is outside the above-mentioned numerical range, the crosslinking agent is difficult to disperse highly in the fluororubber crosslinking composition, and the crosslinking reaction is difficult to proceed uniformly in the fluororubber crosslinking composition.

[0058] If the O-C bond distance L of the compound (b1) is too short or too long, the crosslinking reaction does not proceed at an appropriate rate, and it tends to be difficult to form an appropriate crosslinked network.

[0059] In one embodiment, the compound (b1) has a substituent (α) in which at least one of the Hammett substituent constants σm and σp has a value of 0.03 or more, and has a molecular weight of 12.1 to 17.8 (cal / cm 3) 1 / 2 and the O-C bond distance L is 1.357 to 1.369 Å. In this embodiment, the substituent constants σm and σp can take values ​​within the above-mentioned preferred numerical ranges, and the solubility parameter (SP value) and the O-C bond distance L can take values ​​within the above-mentioned preferred numerical ranges.

[0060] When at least one of the Hammett substituent constants σm and σp of compound (b1) is within the above-mentioned numerical range, and the solubility parameter (SP value) and the O-C bond distance L of compound (b1) are within the above-mentioned numerical range, a molded article can be obtained that has a better balance of elongation and high-temperature compression set properties at an even higher level.

[0061] The solubility parameter (SP value) of compound (b1) can be calculated using the literature published by RF Edors (Polymer Engineering and Science, Vol. 14, No. 147, 1974). The unit is "(cal / cm 3 ) 1 / 2 " The solubility parameter is multiplied by 1.046 to convert the unit to "(MPa 1 / 2 )" can be calculated.

[0062] The O-C bond distance L is the bond distance between the oxygen atom of a hydroxy group directly bonded to a carbon atom constituting an aromatic ring of compound (b1) and the carbon atom constituting the aromatic ring to which this hydroxy group is bonded. Compound (b1) has two or more bonds between oxygen atoms of hydroxy groups and carbon atoms of aromatic rings, and when the respective O-C bond distances L are different, the smallest value is taken as the O-C bond distance L.

[0063] The O-C bond distance L can be determined from a molecular structure obtained by a structure optimization calculation based on the density functional theory. The structure optimization calculation of a compound can be performed, for example, using Gaussian 16, a quantum chemical calculation program manufactured by Gaussian.

[0064] The number of aromatic rings contained in compound (b1) is 2 or more, preferably 2 to 8, more preferably 2 to 4, further preferably 2 to 3, and particularly preferably 2. When the number of aromatic rings is 2 or more, it is preferable that at least one hydroxy group and at least one substituent (α) are directly bonded to each aromatic ring.

[0065] The aromatic ring of the compound (b1) is preferably a polycyclic aromatic hydrocarbon ring or a polycyclic aromatic heterocycle. The substituent (α) replaces a hydrogen atom bonded to a carbon atom constituting the aromatic ring, and thus affects the electron density of a hydroxy group directly bonded to a carbon atom constituting the aromatic ring.

[0066] The polycyclic aromatic hydrocarbon ring may be a polycyclic, fused or spiro ring in which two rings are linked via a bond.

[0067] The polycyclic aromatic hydrocarbon ring has preferably 3 to 30 carbon atoms, more preferably 5 or more, even more preferably 6 or more, and more preferably 20 or less, even more preferably 14 or less.

[0068] The polycyclic aromatic hydrocarbon ring preferably has 2 to 4 rings, more preferably 2 or 3 rings, and further preferably 2 rings.

[0069] Polycyclic aromatic hydrocarbon rings include Polycyclic aromatic hydrocarbon rings 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, or a diphenyl ketone ring; condensed polycyclic hydrocarbon rings such as a naphthalene ring, a phenanthrene ring, an anthracene ring, a fluorene ring, a tetracene ring, a chrysene ring, a pyrene ring, a pentacene ring, a benzopyrene ring, a triphenylene ring, and an azulene ring; etc.

[0070] As the polycyclic aromatic hydrocarbon ring, a polycyclic aromatic hydrocarbon ring in which two rings are linked via a bond is preferred, and a biphenyl ring is preferred.

[0071] In the polycyclic aromatic heterocycle of the present disclosure, the carbonyl group may form a part of the aromatic ring, and the polycyclic aromatic heterocycle also includes a ring formed only from carbon atoms and oxygen atoms of the carbonyl group.

[0072] As the polycyclic aromatic heterocycle, a ring formed by carbon atoms and atoms other than carbon atoms is preferred. As the atoms other than carbon atoms, nitrogen atoms, oxygen atoms, or sulfur atoms are preferred, and oxygen atoms or sulfur atoms are more preferred. That is, as the heterocycle, a nitrogen-containing heterocycle, an oxygen-containing heterocycle, or a sulfur-containing heterocycle is preferred, and oxygen-containing heterocycle or a sulfur-containing heterocycle is more preferred. The number of atoms other than carbon atoms in the ring is preferably 1 to 3.

[0073] The polycyclic aromatic heterocycle preferably has 2 to 4 rings, more preferably 2 or 3 rings, and further preferably 2 rings.

[0074] The polycyclic aromatic heterocycle is preferably an oxygen-containing polycyclic aromatic heterocycle, such as a xanthene ring, a 1-benzopyran ring, a 2-benzopyran ring, a 1-benzofuran ring, or a 2-benzofuran ring.

[0075] The compound (b1) is preferably at least one selected from the group consisting of a fused polycyclic hydrocarbon ring, a polycyclic aromatic heterocycle, and a compound represented by general formula (b1), and more preferably a compound represented by general formula (b1).

[0076] [ka] (In the formula, a and b are each independently 1 or 2; X 1 and X 2are each independently a substituent (α), c and d are each independently an integer of 0 to 3 (with the proviso that the sum of c and d is an integer of 1 or more), A is a single bond, an alkylene group having 1 to 13 carbon atoms, an arylene group having 6 to 13 carbon atoms, a thiocarbonyl group, an oxy group, a carbonyl group, a sulfinyl group or a sulfonyl group, and these groups may contain one or both of a chlorine atom and a fluorine atom.

[0077] In the general formula (b1), a and b represent the number of hydroxy groups bonded to each of the two benzene rings. Each of a and b is independently 1 or 2, and preferably 1. That is, the compound (b1) is preferably a compound represented by the general formula (b1-a). In the general formula (b1), when the sum of c and d is 2 or more, it is preferable that each of the two benzene rings has one or more substituents (α) bonded thereto.

[0078] [ka] (In the formula, X 1 and X 2 are each independently a substituent (α), c and d are each independently an integer of 0 to 3 (with the proviso that the sum of c and d is an integer of 1 or more), A is a single bond, an alkylene group having 1 to 13 carbon atoms, an arylene group having 6 to 13 carbon atoms, a thiocarbonyl group, an oxy group, a carbonyl group, a sulfinyl group or a sulfonyl group, and these groups may contain one or both of a chlorine atom and a fluorine atom.

[0079] A represents the type of bond connecting two benzene rings, and is a single bond, an alkylene group having 1 to 13 carbon atoms, an arylene group having 6 to 13 carbon atoms, a thiocarbonyl group, an oxy group, a carbonyl group, a sulfinyl group, or a sulfonyl group. When these groups have a substitutable hydrogen atom, the hydrogen atom may be substituted with a chlorine atom or a fluorine atom. That is, these groups may contain one or both of a chlorine atom and a fluorine atom.

[0080] A is preferably a single bond or an alkylene group having 1 to 13 carbon atoms, and more preferably a single bond. That is, compound (b1) is preferably a compound represented by general formula (b1-b).

[0081] [ka] (In the formula, X 1 and X 2 are each independently a substituent (α), and c and d are each independently an integer of 0 to 3 (with the proviso that the sum of c and d is an integer of 1 or more).

[0082] As the compound (b1) in which one hydroxy group is bonded to each of the two benzene rings and A is a single bond, a compound represented by any one of general formulas (b1-1), (b1-2) and (b1-3) is preferable.

[0083] [ka] (In the formula, X 1 and X 2 are each independently a substituent (α), and c and d are each independently an integer of 0 to 3 (with the proviso that the sum of c and d is an integer of 1 or more).

[0084] [ka] (In the formula, X 1 and X 2 are each independently a substituent (α), and c and d are each independently an integer of 0 to 3 (with the proviso that the sum of c and d is an integer of 1 or more).

[0085] [ka] (In the formula, X 1 and X 2 are each independently a substituent (α), and c and d are each independently an integer of 0 to 3 (with the proviso that the sum of c and d is an integer of 1 or more).

[0086] In each of the above general formulas, X 1 and X 2 represents a substituent (α) bonded to each of the two benzene rings. Furthermore, c and d represent the number of substituents (α) bonded to each of the two benzene rings. c and d are each independently an integer of 0 to 3, with the proviso that the sum of c and d is an integer of 1 or more. c and d are each independently preferably an integer of 1 to 3, more preferably 1 or 2, and further preferably 1. The substituent (α) is as described above.

[0087] In general formula (b1), general formula (b1-a), general formula (b1-b), general formula (b1-1), general formula (b1-2), and general formula (b1-3), it is preferable that at least one hydroxy group directly bonded to the same benzene ring and at least one substituent (α) satisfy any one of the following conditions: (H-1): The substituent constant σm of the substituent (α) is 0.03 or more, and the substituent (α) and a hydroxy group are bonded to the meta position of the benzene ring. (H-2): The substituent constant σp of the substituent (α) is 0.03 or more, and the substituent (α) and the hydroxyl group are bonded to the ortho position of the benzene ring. (H-3): The substituent constant σp of the substituent (α) is 0.03 or more, and the substituent (α) and the hydroxyl group are bonded to the para position of the benzene ring.

[0088] In addition, it is preferable that at least one hydroxy group and at least one substituent (α) bonded to each of the two benzene rings satisfy any one of the conditions (H-1) to (H-3), It is preferable that at least one hydroxy group and at least one substituent (α) bonded to one benzene ring meet the condition (H-1), and at least one hydroxy group and at least one substituent (α) bonded to the other benzene ring meet any of the conditions (H-1) to (H-3), It is preferred that at least one hydroxy group and at least one substituent (α) bonded to each of the two benzene rings meet the condition (H-1).

[0089] As compound (b1), a compound represented by any one of general formula (b1-1-1), general formula (b1-2-1), general formula (b1-2-2), general formula (b1-3-1), general formula (b1-3-2) and general formula (b1-3-3) is preferable, and a compound represented by general formula (b1-1-1) is particularly preferable.

[0090] [ka] (In the formula, X 1 and X 2 are each independently a substituent (α).

[0091] [ka] (In the formula, X 1 and X 2 are each independently a substituent (α).

[0092] [ka] (In the formula, X 1 and X 2 are each independently a substituent (α).

[0093] [ka] (In the formula, X 1 and X 2 are each independently a substituent (α).

[0094] [ka] (In the formula, X 1 and X 2 are each independently a substituent (α).

[0095] [ka] (In the formula, X 1 and X 2 are each independently a substituent (α).

[0096] In the general formulae (b1-1-1), (b1-2-1), (b1-2-2), (b1-3-1), (b1-3-2) and (b1-3-3), X 1 and X 2 It is preferable that one or both of X is a substituent (α) having a substituent constant σm in the above range, 1 and X 2 It is more preferable that both of the above are substituents (α) having a substituent constant σm in the above range.

[0097] The crosslinking agent may be a salt of compound (b1) and an alkali metal, a salt of compound (b1) and an alkaline earth metal, or a salt of compound (b1) and an onium compound. Among these salts, a salt of compound (b1) and an onium compound is preferred. The salt of the above compound and an onium compound is an onium salt composed of an anion portion derived from the above compound and a cation portion derived from the onium compound. By using an onium salt as the crosslinking agent (b), the onium salt acts not only as a crosslinking agent but also as a crosslinking promoter.

[0098] The salts of compound (b1) and alkali metals, the salts of compound (b1) and alkaline earth metals, and the salts of compound (b1) and onium compounds can be used alone or in combination.

[0099] The salt of compound (b1) and an onium compound can be obtained by reacting compound (b1) with an alkaline substance such as sodium hydroxide in water or an organic solvent, or with metallic sodium in an organic solvent, and then reacting with an onium compound such as benzyltriphenylphosphonium chloride, and distilling off the water or organic solvent. If necessary, the solution of the reaction product may be filtered or the reaction product may be washed with water or an organic solvent during the reaction to remove by-products such as sodium chloride.

[0100] The alkali metal is preferably Na or K. The alkaline earth metal is preferably Ca or Mg.

[0101] Examples of the onium salt include ammonium salts, phosphonium salts, and sulfonium salts.

[0102] Examples of the onium compound constituting the onium salt include ammonium compounds, phosphonium compounds, and sulfonium compounds.

[0103] As the onium compound constituting the onium salt, an ammonium compound or a phosphonium compound is preferable, a phosphonium compound is more preferable, a quaternary phosphonium compound is even more preferable, and among them, benzyltriphenylphosphonium is particularly preferable. As the ammonium compound, a quaternary ammonium compound is preferable, and 8-benzyl-1,8-diazabicyclo[5,4,0]-7-undecenium or benzyldimethyloctadecylammonium is more preferable.

[0104] The crosslinking agent can be used by mixing with other compounds. Examples of the mixture containing the crosslinking agent include a mixture such as a solid solution of the crosslinking agent and the crosslinking promoter, and a mixture of the crosslinking agent and a compound capable of dissolving it. As the mixture of the crosslinking agent and the crosslinking promoter, a mixture of the compound (b1) and a quaternary phosphonium salt or a mixture of the compound (b1) and a quaternary ammonium salt is preferred, a mixture of the compound (b1) and a quaternary phosphonium salt is more preferred, and a mixture of the compound (b1) and benzyltriphenylphosphonium chloride is even more preferred.

[0105] 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, because the crosslinking reaction in the crosslinking step proceeds at an appropriate speed and a molded product having sufficient tensile strength, elongation at break, compression set properties at high temperatures, and appropriate hardness can be obtained. When the crosslinking agent is a salt of the compound (b1) and an onium compound, the content (parts by mass) of the crosslinking agent is a value excluding the mass of the cationic portion of the crosslinking agent (i.e., the cation derived from the onium compound).

[0106] (c) Crosslinking accelerator The fluororubber crosslinking composition of the present disclosure preferably contains a crosslinking accelerator. When a crosslinking accelerator is used, the crosslinking reaction can be accelerated by accelerating the formation of intramolecular double bonds in the defluorination reaction of the fluororubber main chain. When at least one compound selected from the group consisting of compound (b1) and salts of compound (b1) with an alkali metal or an alkaline earth metal is used as the crosslinking agent, it is preferable to use a crosslinking accelerator together with the crosslinking agent. 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 the crosslinking accelerator can be appropriately adjusted depending on the crosslinking conditions and the physical properties of the molded product. If the amount of the crosslinking accelerator is increased, the crosslinking reaction becomes faster or crosslinking can be performed at a lower temperature, but the compression set property tends to deteriorate. Conversely, if the amount of the crosslinking accelerator is reduced, the crosslinking reaction becomes slower, but the compression set property tends to improve.

[0107] As a crosslinking accelerator for a polyol crosslinking system, an onium compound (excluding a salt of compound (b1) and an onium compound) is generally used. 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, among which quaternary ammonium salts and quaternary phosphonium salts are preferred.

[0108] 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, and tetrabutylammonium hydroxide. Among these, DBU-B or benzyldimethyloctadecylammonium chloride is preferred from the viewpoints of crosslinkability and physical properties of the crosslinked product.

[0109] 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 physical properties of the crosslinked product.

[0110] The content of the crosslinking accelerator is preferably 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, further preferably 0.1 to 3 parts by mass, and particularly preferably 0.1 to 1.5 parts by mass, based on 100 parts by mass of the fluororubber, because the crosslinking reaction proceeds at an appropriate speed and the compression set property at high temperatures allows the production of a more excellent molded product. When the crosslinking agent is a salt of the compound (b1) and an onium compound, the content of the crosslinking accelerator is a value including the mass of the cationic portion of the crosslinking agent (i.e., the cation derived from the onium compound).

[0111] (d) Acid acceptor The fluororubber crosslinking composition of the present disclosure may further contain an acid acceptor. By containing an acid acceptor, the crosslinking reaction of the fluororubber crosslinking composition proceeds more smoothly, and the compression set properties at high temperatures are further improved.

[0112] 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-2003-277563, etc. Examples of the metal salts of weak acids include carbonates, benzoates, oxalates, and phosphites of Ca, Sr, Ba, Na, and K.

[0113] 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, since it is possible to obtain a molded article with better compression set properties at high temperatures, and sodium metasilicate hydrate, calcium hydroxide, magnesium oxide, bismuth oxide, and hydrotalcite are more preferred. In addition, when the molded article to be obtained requires good water resistance, acid resistance, or resistance to organic acid esters including biodiesel, the acid acceptor is preferably at least one selected from the group consisting of bismuth oxide and hydrotalcite.

[0114] In the fluororubber cross-linking 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, relative to 100 parts by mass of the fluororubber, since a molded product with even better compression set properties at high temperatures can be obtained.

[0115] When the content of the acid acceptor is increased, the water resistance, acid resistance, and resistance to organic acid esters including biodiesel of the obtained molded article tend to decrease, while when the content of the acid acceptor is decreased, the crosslinking speed decreases, and the mechanical properties tend to decrease due to the decrease in crosslink density. Therefore, the content of the acid acceptor can be selected according to the application of the obtained molded article. When an acid acceptor other than calcium hydroxide is contained, the content of calcium hydroxide is reduced to 0 to 1.5 parts by mass, and then the content of the other acid acceptor is adjusted to adjust the crosslink density, thereby obtaining a molded article with better compression set properties at high temperatures.

[0116] (e) Other ingredients The fluororubber cross-linking composition may be blended with various additives as required, such as usual additives blended in fluororubber cross-linking compositions, for example, 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-tacky agents, flexibility imparting agents, heat resistance improving agents, flame retardants, foaming agents, and antioxidants described in WO 2012 / 023485, and may also be blended with one or more usual cross-linking agents and cross-linking accelerators different from the above.

[0117] Of these, the carbon black is preferably thermal carbon black or furnace carbon black, more preferably MT carbon black, FT carbon black, or SRF carbon black. When carbon black or carbon black with a relatively large particle size such as FT carbon black is blended, a molded product with excellent compression set properties is obtained, and when carbon black with a fine particle size is blended, a molded product with excellent strength and elongation is obtained. By blending different grades in combination, the above properties can be balanced.

[0118] As fillers other than carbon black, barium sulfate and wollastonite are preferred.

[0119] 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 sebacic acid 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 the mold releasability during molding and the physical properties of the molded product.

[0120] 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, further 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.

[0121] 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 fluororubber. When processing aids, plasticizers, and release agents are used, the mechanical properties and sealing properties of the resulting molded product tend to decrease, so it is necessary to adjust the content of these agents within a range in which the properties of the desired molded product are acceptable.

[0122] The fluororubber crosslinking composition may contain a dialkylsulfone compound. By containing a dialkylsulfone compound, the crosslinking efficiency of the fluororubber crosslinking composition is increased, the crosslinking speed is increased, the compression set property is further improved, and the flowability of the rubber material is improved. Examples of the dialkylsulfone compound include dimethylsulfone, diethylsulfone, dibutylsulfone, methylethylsulfone, diphenylsulfone, and sulfolane. Among them, sulfolane is preferred from the viewpoint of crosslinking efficiency and compression set property, and because it has an appropriate boiling point. The content of the dialkylsulfone 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, relative to 100 parts by mass of the fluororubber. When the fluororubber crosslinking composition of the present disclosure contains a dialkylsulfone compound, the lower limit of the content of the dialkylsulfone compound may be, for example, 0.1 parts by mass or more relative to 100 parts by mass of the fluororubber.

[0123] The dialkyl sulfone compound and the processing aid may be blended together, as this provides a good balance between the crosslinking rate, the fluidity of the rubber material during molding, the mold releasability during molding, and the mechanical properties of the molded product.

[0124] The fluororubber crosslinking composition is obtained by kneading the fluororubber (a), the crosslinking agent (b), the crosslinking accelerator (c), the acid acceptor (d), and other components (e) using a commonly used rubber kneading device. As the rubber kneading device, a roll, a kneader, a Banbury mixer, an internal mixer, a twin-screw extruder, etc. can be used.

[0125] In order to uniformly disperse each component in the rubber, a method may be used in which the fluororubber (a), the crosslinking agent (b) and the crosslinking accelerator (c) are kneaded while being melted at a high temperature of 100 to 200°C using a closed kneading device such as a kneader, and then the acid acceptor (d) and other components (e) are kneaded at a relatively low temperature below this temperature.

[0126] Furthermore, the dispersibility can be further improved by mixing the fluororubber (a), the crosslinking agent (b), the crosslinking accelerator (c), the acid acceptor (d), and other components (e), leaving the mixture at room temperature for 12 hours or more, and then mixing it again.

[0127] <Molded products> The molded article of the present disclosure can be obtained by crosslinking the fluororubber crosslinking composition. The molded article of the present disclosure can also be obtained by molding and crosslinking the fluororubber crosslinking composition. The fluororubber crosslinking 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 to be adopted. 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.

[0128] Examples of the molding method include, but are not limited to, compression molding, casting, injection molding, extrusion molding, and roto-cure molding. Examples of the crosslinking method include steam crosslinking, heat crosslinking, and radiation crosslinking, among which steam crosslinking and heat crosslinking are preferred. Specific crosslinking conditions that are not limited to these are usually within a temperature range of 140 to 250°C and a crosslinking time of 1 minute to 24 hours, and may be appropriately determined depending on the types of crosslinking agent (b), crosslinking accelerator (c), and acid acceptor (d).

[0129] 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, are usually within a temperature range of 140 to 300°C and a time range of 30 minutes to 72 hours, and may be appropriately determined depending on the types of crosslinking agent (b), crosslinking accelerator (c), acid acceptor (d), etc.

[0130] 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, and are intended for vibration and sound insulation, and can be used as various parts in various fields such as the automobile industry, the aircraft industry, and the semiconductor industry.

[0131] 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 steel 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 for oil and gas, oil refining, and oil transportation equipment parts.

[0132] Examples of the 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.

[0133] They can also be used as tubes, hoses, rolls, various rubber rolls, flexible joints, rubber sheets, coatings, belts, dampers, valves, valve seats, valve bodies, chemical-resistant coating materials, laminating materials, lining materials, etc.

[0134] The cross-sectional shape of the above-mentioned rings, packings, and seals may be of various shapes, and specifically, for example, may be rectangular, O-shaped, ferrule-shaped, or may be an irregular shape such as D-shaped, L-shaped, T-shaped, V-shaped, X-shaped, or Y-shaped.

[0135] In the above-mentioned 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 / O3 cleaning equipment, ion beam cleaning equipment, laser beam cleaning equipment, plasma cleaning equipment, gas etching cleaning equipment, etc. Examples of such equipment include equipment for plasma treatment such as, extraction and cleaning equipment, Soxhlet extraction and cleaning equipment, high temperature and high pressure extraction and cleaning equipment, microwave extraction and cleaning equipment, supercritical extraction and cleaning equipment, cleaning equipment that uses hydrofluoric acid, hydrochloric acid, sulfuric acid, ozone water, etc., steppers, coater / developers, CMP equipment, excimer laser exposure machines, chemical liquid piping, gas piping, equipment for plasma treatment such as NF3 plasma treatment, O2 plasma treatment, 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.

[0136] Specific examples of uses in the semiconductor-related field include 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 solution, hoses and tubes; linings and coatings for resist developer tanks, stripper solution tanks, wafer cleaning solution tanks, and wet etching tanks; pump diaphragms; rolls for transporting wafers; hose tubes for wafer cleaning solution; sealing materials for clean facilities such as sealants for clean rooms and other clean facilities; sealing materials for semiconductor manufacturing equipment and storage facilities for storing devices such as wafers; and diaphragms for transporting chemical solutions used in the semiconductor manufacturing process.

[0137] In the above-mentioned automotive field, the material can be used in the engine body, main motion system, valve train system, lubrication / cooling system, fuel system, intake / 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.

[0138] In the engine 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 gaskets, shaft seals, valve stem seals, and other 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.

[0139] 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 manifolds, fuel filters, pressure regulators, canisters, fuel tank caps, fuel pumps, fuel tanks, fuel tank sender units, fuel injection systems, 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, on-board refueling vapor recovery (ORVR) valve seals, oil seals for fuel pumps, fuel sender seals, fuel tank rollover valve seals, filler seals, injector seals, filler cap seals, filler cap valve seals; fuel hoses, Fuel supply hoses, fuel return hoses, vapor (evaporation) hoses, vent (breather) hoses, filler hoses, filler neck hoses, hoses inside fuel tanks (in-tank hoses), carburetor control hoses, fuel inlet hoses, fuel breather hoses, and other hoses; gaskets used in fuel filters, 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 devices; valves for fuel pumps, carburetor needle valves, rollover check valves, check valves, and other types of valves; vents (breathers), tubes used inside fuel tanks; tank packings for fuel tanks, and packings for carburetor acceleration pump pistons; 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 cores; carburetor accelerator pump pistons; valve seats for compound air control systems (CAC); fuel tank bodies; and sealing parts for solenoid valves.

[0140] Specific uses in the above brake systems include diaphragms used in master bags, hydraulic brake hoses, air brakes, and air brake brake chambers; 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 hydraulic brake master cylinders and vacuum boosters, and wheel cylinders of hydraulic brakes, as well as O-rings and grommets for anti-lock braking systems (ABS).

[0141] Specific examples of uses of the basic electrical components include insulators and sheaths for electrical wires (harnesses), tubes for exterior harness components, and grommets for connectors.

[0142] Specific examples of applications in electrical control system components include coating materials for various sensor wires.

[0143] Specific examples of the use of 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, diaphragms for distributors, etc. It can also be used to bond electrical equipment parts.

[0144] Specific examples of applications in the above 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.; hoses such as EGR (exhaust gas recirculation) control hoses, emission control hoses, turbocharger turbo oil hoses (supply), turbo oil hoses (return), turbo air hoses, intercooler hoses, turbocharger hoses, hoses connected to the compressors of turbo engines equipped with intercoolers, 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 materials used in grooved parts such as rocker covers and air intake manifolds used in automobile engines.

[0145] Other applications include seals for vapor recovery canisters, catalytic converters, exhaust gas sensors, oxygen sensors, etc. in emission control components; seals for vapor recovery and vapor canister solenoid armatures; and intake manifold gaskets.

[0146] In addition, in diesel engine parts, it can be used as O-ring seals for direct injection injectors, rotary pump seals, control diaphragms, fuel hoses, EGR, priming pumps, boost compensator diaphragms, etc. It can also be used in O-rings, seal materials, hoses, tubes, diaphragms, gasket materials, pipes used in urea SCR systems, the urea water tank body of the urea SCR system, and seal materials for the urea water tank.

[0147] Specific examples of applications in the above-mentioned 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.

[0148] Transmissions include AT (automatic transmission), MT (manual transmission), CVT (continuously variable transmission), and DCT (dual clutch transmission).

[0149] 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).

[0150] Specific examples of uses in steering systems include power steering oil hoses and high-pressure power steering hoses.

[0151] 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; anti-vibration rubber for engine mounts, control valve diaphragms, and camshaft oil seals.

[0152] In the main drive system of an automobile engine, it can be used as a shaft seal such as a crankshaft seal or a camshaft seal.

[0153] 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.

[0154] In the lubrication and cooling systems of automobile engines, it can be used in 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.

[0155] Thus, 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, seals for sulfur oxide sensors, seals for temperature sensors, temperature sensor bushings, seals for diesel particle filter sensors, diesel particle filter sensor bushings, injector O-rings, injector packings, O-rings and diaphragms for fuel pumps, gearbox seals, power piston packings, cylinder liner seals, valve stem seals, static valve stem seals, dynamic valve stem seals, front pump seals for automatic transmissions, rear axle pinion seals, universal joint gaskets, pinion seals for speedometers, piston cups for foot brakes, O-rings and oil seals for torque transmission devices, seals and bearing seals for exhaust gas re-burners, hoses for re-burners, Carburetor sensor diaphragms, anti-vibration rubber (engine mounts, exhaust parts, muffler hangers, suspension bushes, center bearings, strut bumper rubber, etc.), anti-vibration rubber for suspensions (strut mounts, bushes, etc.), anti-vibration rubber for drive systems (dampers, etc.), fuel hoses, EGR tubes and hoses, twin carb 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, rubber hoses for engine intercoolers, fuel line connector devicesSeals for automotive systems, CAC valves, needle tips, engine wiring, filler hoses, O-rings for car air conditioners, intake gaskets, fuel tank materials, distributor diaphragms, water hoses, clutch hoses, PS hoses, AT hoses, master back hoses, heater hoses, air conditioner 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, centre unit packing, body site welts, bumper rubber, door latches, dash insulators, high tension cords, flat belts, poly V-belts, timing belts, toothed belts, V-ribbed belts, tyres, 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, OPS 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 unit 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 coatings, caliper seals, boots, wheel bearing seals, and bladders used in the vulcanization molding of tires.

[0156] In the above-mentioned aircraft, space / rocket and ship fields, the composition can be used particularly in fuel systems and lubricating oil systems.

[0157] In the above-mentioned 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.

[0158] In the space and rocket fields, they can be used, for example, as lip seals, diaphragms, and O-rings for spacecraft, jet engines, missiles, etc., O-rings for oil-resistant gas turbine engines, and vibration isolation pads for missile ground control.

[0159] In addition, in the marine field, the material can be used, for example, as a stern seal for a screw propeller shaft, a valve stem seal for the intake and exhaust of 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.

[0160] 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 a high level of chemical resistance, for example, processes for producing chemical products such as pharmaceuticals, agricultural chemicals, paints, and resins.

[0161] Specific uses in the above-mentioned chemical and pharmaceutical fields include chemical equipment, chemical pumps and flow meters, chemical piping, heat exchangers, agricultural chemical sprayers, agricultural chemical transfer pumps, gas piping, fuel cells, analytical equipment and physicochemical equipment (for example, column fittings for analytical equipment and instruments), shrink joints for flue gas desulfurization equipment, nitric acid plants, seals used in power plant turbines, etc., seals used in medical sterilization processes, seals for plating solutions, roller seals for papermaking belts, joint seals for wind tunnels; 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, O-rings for compressor sealing; packing used in high-temperature vacuum dryers, tube connections for gas chromatography and pH meters, etc., and glass cooling for sulfuric acid manufacturing equipment. Examples of suitable applications include: instrument packing; diaphragms used in diaphragm pumps, analytical equipment, and physicochemical equipment; gaskets used in analytical equipment and instruments; ferrules used in analytical equipment and instruments; valve seats; U-cups; linings used in chemical equipment, gasoline tanks, wind tunnels, etc., and corrosion-resistant linings for anodized tanks; coatings for masking jigs for plating; valve parts for analytical equipment and physicochemical equipment; expansion joints in flue gas desulfurization plants; acid-resistant hoses for concentrated sulfuric acid, chlorine gas transfer hoses, oil-resistant hoses, and rainwater drain hoses for benzene and toluene storage tanks; chemical-resistant tubes and medical tubes used in analytical equipment and physicochemical equipment; 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- and solvent-resistant gloves and boots.

[0162] In the photographic field such as the developing machines, the printing field such as printing machines, and the coating field such as coating equipment, the composition can be used as rolls, belts, seals, valve parts, etc. of dry copying machines.

[0163] Specific examples of use in the above-mentioned photographic, printing and coating fields include the surface layer of a transfer roll in a copier, a cleaning blade in a copier, and a belt in a copier; rolls (for example, fixing rolls, pressure rolls, etc.) 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, and gravure rolls and coating rolls in magnetic tape production coating lines.

[0164] In the food equipment field, including the food plant equipment and household goods, the present invention can be used in food manufacturing processes, food transport devices, or food storage devices.

[0165] Specific examples of use in the food equipment field include seals for plate-type heat exchangers, solenoid valve seals for vending machines, packing for jar pots, sanitary pipe packing, packing for pressure cookers, seals for water heaters, gaskets for heat exchangers, diaphragms and packing for food processing equipment, rubber materials for food processing equipment (for example, heat exchanger gaskets, various seals such as diaphragms and O-rings, piping, hoses, sanitary packing, valve packing, packing for filling used as a joint between the mouth of a bottle or the like and the filler during filling), etc. Other examples include packing, gaskets, tubes, diaphragms, hoses, joint sleeves, etc. 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.

[0166] In the field of nuclear power plant equipment, the material can be used for check valves and pressure reducing valves around nuclear reactors, and as seals for uranium hexafluoride enrichment equipment.

[0167] Specific examples of use 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 machines; sealing materials used for mandrels, etc.; seals used for windows of dry cleaning equipment, etc.; 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 devices), snake pump linings, rolls and belts for printing machines, transport belts (conveyor belts), squeeze rolls for pickling iron plates, etc., robot cables, solvent squeeze rolls for aluminum rolling lines, O-rings for couplers, acid-resistant cushioning materials, dust seals and lip rubbers for the sliding parts of cutting machines, gaskets for food waste incineration machines, friction materials, metal or rubber surface modifiers, coating materials, etc. They can also be used as gaskets and sealing materials for equipment used in papermaking processes, sealants for clean room filter units, architectural sealants, protective coatings for concrete and cement, glass cloth impregnation materials, polyolefin processing aids, polyethylene moldability improving additives, fuel containers for small generators and lawnmowers, precoated metals obtained by subjecting metal plates to a primer treatment, etc. They can also be used as sheets and belts by impregnating woven fabrics and baking them.

[0168] Specific examples of the use in the steel industry include iron plate processing rolls in iron plate processing equipment.

[0169] Specific examples of the use in the electrical field include insulating oil caps for bullet trains, venting seals for liquid-sealed transformers, transformer seals, jackets for oil well cables, seals for ovens such as electric furnaces, window frame seals for microwave ovens, seals used for bonding the wedge and neck of a CRT, seals for halogen lamps, fixing agents for electrical components, seals for the end treatment of sheathed heaters, and seals used for insulating and moisture-proofing treatment of lead wire terminals for electrical equipment. In addition, it can be used as a coating material for oil-resistant and heat-resistant electric wires, high heat-resistant electric wires, chemical-resistant electric wires, high insulation electric wires, high voltage 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 be used as an electrical insulating material (for example, insulating spacers for various electrical devices, insulating tapes for cable joints and ends, materials used for heat-shrinkable tubes, etc.), and materials for electrical and electronic devices used in high-temperature atmospheres (for example, materials for motor lead wires and wire materials around high-temperature furnaces). It can also be used as a sealing layer or protective film (back sheet) for solar cells.

[0170] 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, packing, and separators for piping for hydrogen, oxygen, generated water, etc.

[0171] 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. In addition, it is also used as a shock absorbing rubber (crash stopper) for hard disk drives, a binder for electrode active materials in nickel-hydrogen secondary batteries, a binder for active materials in lithium ion batteries, a polymer electrolyte for lithium secondary batteries, a binder for the positive electrode of alkaline storage batteries, a binder for EL elements (electroluminescence elements), a binder for electrode active materials in capacitors, a sealant, a sealing agent, a quartz coating material for optical fibers, films and sheets such as optical fiber coating materials, electronic components such as CMOS electronic circuits, transistors, integrated circuits, organic transistors, light emitting elements, actuators, memories, sensors, coils, capacitors, and resistors, potting, coating, and adhesive seals for circuit boards, fixing agents for electronic components, a modifying agent for sealants such as epoxy, a coating agent for printed circuit boards, a modifying agent for printed wiring board prepreg resin such as epoxy, a shatterproofing material for light bulbs, a gasket for computers, a large computer cooling hose, a packing such as a gasket or O-ring for secondary batteries, in particular, a sealing layer covering one or both sides of the outer surface of an organic EL structure, a connector, a damper, and the like.

[0172] In the field of chemical transport equipment, the valves can be used as safety valves and shipping valves for trucks, trailers, tank trucks, ships, etc.

[0173] In the field of oil, gas and other energy resource exploration and mining equipment parts, they are used as various sealing materials used in mining oil, natural gas and the like, and as boots for electrical connectors used in oil wells.

[0174] 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 MWDs (real-time drilling information detection systems), logging tool seals (e.g., 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 our applications include seals used in drilling equipment, seals, packings and motor linings used in mud pumps, underground hearing tester 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, LWD (logging while drilling) seals, diaphragms used in oil exploration and drilling applications (for example, diaphragms for lubricating oil in oil drilling pits), gate valves, electronic boots, and sealing elements for drilling guns.

[0175] Other uses include sealing joints in kitchens, bathrooms, washrooms, etc.; covering 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 such as laminated steel plates used in the construction and home appliance fields.

[0176] Furthermore, it can also be used as an article combined with a metal such as aluminum, etc. Examples of such uses include door seals, gate valves, pendulum valves, solenoid tips, as well as piston seals and diaphragms combined with metals, metal-rubber parts combined with metals such as metal gaskets, etc.

[0177] It can also be used for rubber parts, brake shoes, brake pads, etc. in bicycles.

[0178] The molded product can also be applied to belts.

[0179] Examples of belts include the following: power transmission belts (including flat belts, V-belts, V-ribbed belts, toothed belts, etc.), conveyor belts (conveyor belts), flat belts used in various high-temperature locations such as around the engines of agricultural machinery, machine tools, industrial machinery, etc.; conveyor belts for conveying bulk materials and 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 automobiles, office automation equipment, medical use, printing machines, etc.

[0180] In particular, a timing belt is a typical example of a toothed belt for an automobile.

[0181] The belt may have a single layer structure or a multi-layer structure.

[0182] In the case of a multi-layer structure, the belt may be composed of a layer obtained by crosslinking a fluororubber crosslinking composition and a layer composed of another material.

[0183] 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, metal foil layers, and the like.

[0184] The molded products can also be used as industrial anti-vibration pads, anti-vibration mats, railway slab mats, pads, automotive anti-vibration rubber, etc. Examples of automotive anti-vibration rubber include anti-vibration rubber for engine mounts, motor mounts, member mounts, strut mounts, bushes, dampers, muffler hangers, center bearings, etc.

[0185] Other examples of applications include joint members such as flexible joints and expansion joints, boots, grommets, etc. In the marine field, examples include marine pumps, etc.

[0186] Joint materials are connectors 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 or preventing the effects of earthquakes and land subsidence.

[0187] 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 / water piping, and automobiles. The boots can be preferably used as complex shaped molded articles, 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 lubricators, boots for transferring liquids, boots for firefighting, and boots for transferring various liquefied gases.

[0188] The molded articles can also be used as diaphragms for filter presses, blowers, water supply diaphragms, liquid storage tanks, pressure switches, accumulators, and air spring diaphragms for suspensions, etc.

[0189] By adding the molded article to rubber or resin, an anti-slip agent can be obtained which provides a molded article or coating film that is non-slip in wet environments such as rain, snow, ice, and sweat.

[0190] 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.

[0191] The molded articles can also contribute to impermeability of various substrates such as weapon-related sealing gaskets and protective clothing against contact with aggressive chemical agents.

[0192] In addition, it can be used for 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 various sealing materials used to seal lubricating oils (engine oils, transmission oils, gear oils, etc.) containing amine additives (especially amine additives used as antioxidants and detergent dispersants) used in transportation such as automobiles and ships, and can also be used as tubes, hoses, various rubber rolls, coatings, belts, valve bodies of valves, etc. It can also be used as a laminating material and a lining material.

[0193] The material can be used as a coating material for heat- and oil-resistant electric wires used in lead wires of sensors that come into contact with transmission oil and / or engine oil in internal combustion engines of automobiles, etc. and detect the oil temperature and / or oil pressure, and can also be used in high-temperature oil environments such as in automatic transmissions and engine oil pans.

[0194] In addition, vulcanized coatings may be formed on molded products for use.Specific applications include non-adhesive oil-resistant rolls for copying machines, weather-resistant anti-icing weather strips, rubber stoppers for infusions, rubber vial stoppers, mold release agents, non-adhesive light-duty conveyor belts, anti-adhesive coatings for plate gaskets in automobile engine mounts, coatings for synthetic fibers, bolt members or joints with a thin packing coating layer, etc.

[0195] The use of molded products for automobile-related parts also includes use for motorcycle parts of similar structure.

[0196] Furthermore, examples of the fuels used in the automobile industry include diesel oil, gasoline, and fuels for diesel engines (including biodiesel fuels).

[0197] The molded article can also be used as a sealing member for a rolling bearing.

[0198] The rolling bearings include ball bearings, roller bearings, bearing units, linear bearings, and the like.

[0199] Examples of the ball bearing include a radial ball bearing, a thrust ball bearing, and a thrust angular ball bearing.

[0200] 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.

[0201] The above deep groove ball bearing is used in, for example, electric motors, household electrical appliances, office automation equipment, and the like.

[0202] The angular contact ball bearings mentioned above include single-row angular contact ball bearings, combination angular contact ball bearings, double-row angular contact ball bearings, etc. Single-row angular contact ball bearings are used in electric motors, household electrical appliances, office equipment, etc., as well as hydraulic pumps and vertical pumps that are subject to axial loads in addition to radial loads. Combination angular contact ball bearings are used in main shafts of machine tools 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.

[0203] The four-point contact ball bearings described above are subjected to axial loads from both directions and are used in reducers and other devices where a large space cannot be provided for the bearing width.

[0204] The self-aligning ball bearings are used in places where it is difficult to align the shaft with the housing, or for transmission shafts which are prone to bending.

[0205] The thrust ball bearings include single-direction thrust ball bearings and double-direction thrust ball bearings, and are applicable to conventionally known applications in which these ball bearings are used.

[0206] The above-mentioned thrust angular ball bearing is used in combination with a double row cylindrical roller bearing to receive the axial load of the main shaft of a machine tool.

[0207] Examples of the roller bearing include a radial roller bearing and a thrust roller bearing.

[0208] Examples of the radial roller bearing include cylindrical roller bearings, needle roller bearings, tapered roller bearings, and spherical roller bearings.

[0209] The cylindrical roller bearings are used in general machinery, machine tools, electric motors, reducers, railway axles, aircraft, etc.

[0210] Needle roller bearings are used in general machinery, automobiles, electric motors, etc.

[0211] Tapered roller bearings are used in machine tools, automotive and railway axles, rolling mills, reducers, etc.

[0212] Spherical roller bearings are used in general machinery, rolling mills, paper-making machines, axles, etc.

[0213] Examples of the thrust roller bearing include a cylindrical thrust roller bearing, a needle thrust roller bearing, a tapered thrust roller bearing, and a spherical thrust roller bearing.

[0214] Thrust cylindrical roller bearings are used in machine tools, general machinery, etc.

[0215] Needle roller thrust bearings are used in automobiles, pumps, general machinery, etc.

[0216] Tapered roller thrust bearings are used in general machinery, rolling mills, etc.

[0217] Spherical thrust roller bearings are used in cranes, extruders, general machinery, etc.

[0218] The fluororubber cross-linking composition can be used as various parts in various industrial fields other than as a molded article after cross-linking. Next, the uses of the fluororubber cross-linking composition will be described.

[0219] The fluororubber cross-linking 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-adhesiveness, such as metal gaskets and oil seals; non-adhesive coating materials or bleed barriers for office automation equipment rolls and office automation equipment belts; and coating by impregnation or baking onto woven fabric sheets and belts.

[0220] The fluororubber cross-linking composition can be used as a sealing material, lining, or sealant with complex shapes by ordinary methods when it has a high viscosity and high concentration, can be used to form thin films of several microns when it has a low viscosity, and can be used to apply pre-coated metals, O-rings, diaphragms, and reed valves when it has a medium viscosity.

[0221] Furthermore, it can also be used to coat transport rolls or belts for woven fabrics or paper sheets, printing belts, chemical-resistant tubes, drug plugs, fuel hoses, etc.

[0222] Examples of article substrates to be coated with the fluororubber cross-linking composition include metals such as iron, stainless steel, copper, aluminum, brass, etc.; glass products such as glass plates, woven and nonwoven fabrics of glass fibers; molded products and coatings of general-purpose and heat-resistant resins such as polypropylene, polyoxymethylene, polyimide, polyamideimide, polysulfone, polyethersulfone, polyetheretherketone, etc.; molded products and coatings of general-purpose rubbers such as SBR, butyl rubber, NBR, EPDM, and heat-resistant rubbers such as silicone rubber, fluororubber, etc.; woven and nonwoven fabrics of natural and synthetic fibers; and the like.

[0223] Coatings formed from the fluororubber crosslinking composition can be used in fields requiring heat resistance, solvent resistance, lubricity and non-stickiness, and specific applications include rolls (e.g., 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, engine gaskets and the like.

[0224] The fluororubber crosslinking 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).

[0225] The fluororubber cross-linking 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 and organic base materials such as metals, ceramics, glass, stone, concrete, plastics, rubber, wood, paper, and fiber.

[0226] The fluororubber cross-linking composition can be applied to a substrate or the like by dispenser coating or screen printing coating.

[0227] The fluororubber crosslinking composition may be used as a coating composition for casting a film or for dipping a substrate such as a fabric, plastic, metal, or elastomer.

[0228] In particular, the fluororubber crosslinking composition, in the form of a latex, may be used to make coating 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.

[0229] They are useful for coating silicone rubber, nitrile rubber, and other elastomers. They are also useful for coating parts made from such elastomers for the purpose of enhancing 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 ducts, and containment structures, such as concrete containment structures. The fluoroelastomer crosslinking composition may be applied to exposed cross sections of multi-layer component structures, such as in hose construction and diaphragm manufacturing processes. Sealing members in connections and joints are often made of hard materials, and the fluoroelastomer crosslinking composition provides improved frictional interfaces, enhanced dimensional interference fits with reduced micro-leakage along the sealing surfaces. The latex enhances seal durability in various automotive system applications.

[0230] 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. A further utility of the fluororubber crosslinking composition is in repairing manufacturing defects (and damage caused by use) in multi-layer rubber structures such as three-layer fuel hoses. The fluororubber crosslinking composition is also useful in coating thin steel sheets, which may be formed or embossed before or after paint is applied. For example, multiple layers of coated steel may be assembled to make a gasket between two rigid metal members. The sealing effect is obtained by applying the fluororubber crosslinking composition between the layers. This process can be used to manufacture engine head gaskets and exhaust manifold gaskets for the purpose of lowering the bolt forces and strains of the assembled parts while providing good fuel economy and low emissions due to low cracks, deflections, and hole strains.

[0231] The fluororubber cross-linking 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 metal or ceramic; or a multi-layered product formed by coating a substrate containing an inorganic material such as metal or ceramic.

[0232] The fluororubber crosslinking composition is also suitable as a wiring material for light and flexible electronic devices, and can be used in known electronic components. Examples of electronic components include CMOS electronic circuits, transistors, integrated circuits, organic transistors, light-emitting elements, actuators, memories, sensors, coils, capacitors, and resistors. By using this, 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.

[0233] Although the embodiments have been described above, it will be understood that various changes in form and details are possible without departing from the spirit and scope of the claims.

[0234] <1> According to a first aspect of the present disclosure, The present invention comprises a fluororubber (a) and a crosslinking agent (b), wherein the crosslinking agent (b) is Compounds (b1) having two or more aromatic rings, two or more hydroxy groups directly bonded to carbon atoms constituting the aromatic rings, and one to six substituents (α) (excluding bromine atoms, amino groups, sulfanyl groups, acid groups and groups containing these groups) having at least one of the Hammett substituent constants σm and σp of 0.03 or more directly bonded to carbon atoms constituting the aromatic rings, and A salt of compound (b1) with an alkali metal, an alkaline earth metal or an onium compound The present invention provides a composition for crosslinking fluororubber, which is at least one type selected from the group consisting of: <2> According to a second aspect of the present disclosure, The present invention comprises a fluororubber (a) and a crosslinking agent (b), wherein the crosslinking agent (b) is at least one selected from the group consisting of a compound (b1) having two or more aromatic rings, two or more hydroxy groups directly bonded to carbon atoms constituting the aromatic rings, and one to six substituents (α) (excluding bromine atoms, amino groups, sulfanyl groups, acid groups and groups containing these groups) directly bonded to carbon atoms constituting the aromatic rings, and a salt of the compound (b1) with an alkali metal, an alkaline earth metal or an onium compound, The solubility parameter (SP value) of compound (b1) calculated by the Fedors equation is 12.1 to 17.8 (cal / cm 3 ) 1 / 2 and The compound (b1) has a distance (OC bond distance L) between the oxygen atom of the hydroxy group and the carbon atom to which the hydroxy group is directly bonded, of 1.357 to 1.369 Å. <3> According to a third aspect of the present disclosure, There is provided a fluororubber crosslinking composition according to a second aspect, in which at least one of the Hammett substituent constants σm and σp of the substituent (α) has a value of 0.03 or more. <4> According to a fourth aspect of the present disclosure, There is provided a composition for crosslinking a fluororubber according to any one of the first to third aspects, in which the aromatic ring of the compound (b1) is a polycyclic aromatic hydrocarbon ring or a polycyclic aromatic heterocycle, and the substituent (α) is directly bonded to the aromatic ring. <5> According to a fifth aspect of the present disclosure, There is provided a composition for crosslinking fluororubber according to any one of the first to fourth aspects, in which the aromatic ring of compound (b1) has at least one benzene ring to which one or more hydroxy groups and one or more substituents (α) are directly bonded, and the at least one hydroxy group and the at least one substituent (α) bonded to the benzene ring satisfy any one of the following conditions: (H-1): The substituent constant σm of the substituent (α) is 0.03 or more, and the substituent (α) and a hydroxy group are bonded to the meta position of the benzene ring. (H-2): The substituent constant σp of the substituent (α) is 0.03 or more, and the substituent (α) and the hydroxyl group are bonded to the ortho position of the benzene ring. (H-3): The substituent constant σp of the substituent (α) is 0.03 or more, and the substituent (α) and the hydroxyl group are bonded to the para position of the benzene ring. <6> According to a sixth aspect of the present disclosure, There is provided a composition for crosslinking a fluororubber according to any one of the first to fourth aspects, in which the compound (b1) is at least one selected from the group consisting of a condensed polycyclic hydrocarbon ring, a polycyclic aromatic heterocycle, and a compound represented by the general formula (b1). [ka] (In the formula, a and b are each independently 1 or 2; X 1 and X 2are each independently a substituent (α), c and d are each independently an integer of 0 to 3 (with the proviso that the sum of c and d is an integer of 1 or more), A is a single bond, an alkylene group having 1 to 13 carbon atoms, an arylene group having 6 to 13 carbon atoms, a thiocarbonyl group, an oxy group, a carbonyl group, a sulfinyl group or a sulfonyl group, and these groups may contain one or both of a chlorine atom and a fluorine atom. <7> According to a seventh aspect of the present disclosure, There is provided a composition for crosslinking fluororubber according to any one of the first to fourth aspects, in which the compound (b1) is a compound represented by general formula (b1). [ka] (In the formula, a and b are each independently 1 or 2; X 1 and X 2 are each independently a substituent (α), c and d are each independently an integer of 0 to 3 (with the proviso that the sum of c and d is an integer of 1 or more), A is a single bond, an alkylene group having 1 to 13 carbon atoms, an arylene group having 6 to 13 carbon atoms, a thiocarbonyl group, an oxy group, a carbonyl group, a sulfinyl group or a sulfonyl group, and these groups may contain one or both of a chlorine atom and a fluorine atom. <8> According to an eighth aspect of the present disclosure, According to a seventh aspect, there is provided a composition for crosslinking fluororubber, in which, in general formula (b1), at least one hydroxy group and at least one substituent (α) directly bonded to the same benzene ring satisfy any one of the following conditions: (H-1): The substituent constant σm of the substituent (α) is 0.03 or more, and the substituent (α) and a hydroxy group are bonded to the meta position of the benzene ring. (H-2): The substituent constant σp of the substituent (α) is 0.03 or more, and the substituent (α) and the hydroxyl group are bonded to the ortho position of the benzene ring. (H-3): The substituent constant σp of the substituent (α) is 0.03 or more, and the substituent (α) and the hydroxyl group are bonded to the para position of the benzene ring. <9> According to a ninth aspect of the present disclosure, According to a seventh or eighth aspect, there is provided a composition for crosslinking fluororubber, wherein the compound (b1) is a compound represented by general formula (b1-a). [ka] (In the formula, X 1 and X 2 are each independently a substituent (α), c and d are each independently an integer of 0 to 3 (with the proviso that the sum of c and d is an integer of 1 or more), A is a single bond, an alkylene group having 1 to 13 carbon atoms, an arylene group having 6 to 13 carbon atoms, a thiocarbonyl group, an oxy group, a carbonyl group, a sulfinyl group or a sulfonyl group, and these groups may contain one or both of a chlorine atom and a fluorine atom. <10> According to a tenth aspect of the present disclosure, According to any one of the seventh to ninth aspects, there is provided a composition for crosslinking fluororubber, wherein the compound (b1) is a compound represented by general formula (b1-b). [ka] (In the formula, X 1 and X 2 are each independently a substituent (α), and c and d are each independently an integer of 0 to 3 (with the proviso that the sum of c and d is an integer of 1 or more). <11> According to an eleventh aspect of the present disclosure, There is provided a composition for crosslinking fluororubber according to any one of the seventh to tenth aspects, wherein the compound (b1) is a compound represented by any one of general formula (b1-1), general formula (b1-2), and general formula (b1-3). [ka] [ka] [ka] (In each formula, X 1 and X 2are each independently a substituent (α), and c and d are each independently an integer of 0 to 3 (with the proviso that the sum of c and d is an integer of 1 or more). <12> According to a twelfth aspect of the present disclosure, There is provided a composition for crosslinking fluororubber according to any one of the seventh to eleventh aspects, wherein compound (b1) is a compound represented by any one of general formula (b1-1-1), general formula (b1-2-1), general formula (b1-2-2), general formula (b1-3-1), general formula (b1-3-2) and general formula (b1-3-3). [ka] [ka] [ka] [ka] [ka] [ka] (In each formula, X 1 and X 2 are each independently a substituent (α). <13> According to a thirteenth aspect of the present disclosure, There is provided a composition for cross-linking fluororubber according to any of the first to twelfth aspects, in which the substituent (α) is at least one selected from the group consisting of a perfluoroalkyl group having 1 to 5 carbon atoms, a fluorine atom, a chlorine atom, an alkoxy group having 1 to 5 carbon atoms, an alkoxycarbonyl group having 0 to 5 carbon atoms (excluding the number of carbon atoms constituting the carbonyl group), and an acyl group having 0 to 5 carbon atoms (excluding the number of carbon atoms constituting the carbonyl group). <14> According to a fourteenth aspect of the present disclosure, According to any one of the first to thirteenth aspects, there is provided a composition for crosslinking a fluororubber, wherein the fluororubber (a) contains vinylidene fluoride units. <15> According to a fifteenth aspect of the present disclosure, There is provided a composition for cross-linking fluororubber according to any one of the first to fourteenth aspects, in which the content of the cross-linking agent (b) is 0.1 to 10 parts by mass relative to 100 parts by mass of the fluororubber (a). <16> According to a sixteenth aspect of the present disclosure, There is provided a composition for cross-linking a fluororubber according to any one of the first to fifteenth aspects, further comprising a cross-linking accelerator (c), the content of the cross-linking accelerator (c) being 0.1 to 10 parts by mass per 100 parts by mass of the fluororubber (a). <17> According to a seventeenth aspect of the present disclosure, There is provided a composition for crosslinking a fluororubber according to any one of the first to sixteenth aspects, further comprising an acid acceptor (d), the acid acceptor (d) being 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. <18> According to an eighteenth aspect of the present disclosure, There is provided a composition for crosslinking a fluororubber according to any one of the first to seventeenth aspects, further comprising an acid acceptor (d), the content of the acid acceptor (d) being 0.1 to 50 parts by mass per 100 parts by mass of the fluororubber (a). <19> According to a nineteenth aspect of the present disclosure, There is provided a molded article obtained from the fluororubber crosslinking composition according to any one of the first to eighteenth aspects. EXAMPLES

[0235] Next, embodiments of the present disclosure will be described with reference to examples, but the present disclosure is not limited to these examples.

[0236] The values ​​in the examples were measured by the following methods.

[0237] <Monomer composition of fluororubber> 19 The measurements were performed using an F-NMR (Bruker AC300P model).

[0238] <Fluorine content> 19 The composition of the fluororubber was calculated from the F-NMR data.

[0239] <Mooney viscosity> Measurements were performed in accordance with ASTM D1646-15 and JIS K6300-1:2013 at a temperature of 121°C.

[0240] <Glass transition temperature (Tg)> A DSC curve was obtained by heating 10 mg of a sample at 20°C / min using a differential scanning calorimeter (DSC822e, Mettler Toledo, or X-DSC7000, Hitachi High-Tech Science). The glass transition temperature was determined as the temperature at the intersection of the extension of the baseline before and after the second-order transition of the DSC curve and the tangent to the inflection point of the DSC curve.

[0241] <Heat of fusion> A differential scanning calorimeter (DSC822e, Mettler Toledo, or X-DSC7000, Hitachi High-Tech Science) was used to obtain a DSC curve by heating 10 mg of the sample at 20°C / min, and the heat of fusion was calculated from the magnitude of the melting peak (ΔH) that appeared in the DSC curve.

[0242] <Cross-linking characteristics (maximum torque (MH), optimal cross-linking time (T90))> For the fluororubber crosslinking composition, a vulcanization tester (MDR H2030, manufactured by M&K Co., Ltd.) was used during the primary crosslinking to obtain a crosslinking curve at the temperatures listed in Table 1, and the maximum torque (MH) and optimal crosslinking time (T90) were determined from the change in torque.

[0243] <Tensile strength and elongation at break> A test piece in the shape of a dumbbell No. 6 was prepared from a crosslinked sheet with a thickness of 2 mm. Using the obtained test piece and a tensile tester (A&D Corporation, Tensilon RTG-1310), the tensile strength and elongation at break were measured at 23°C under the condition of 500 mm / min in accordance with JIS K6251:2010.

[0244] <Hardness> Three crosslinked sheets with a thickness of 2 mm were stacked, and the durometer hardness (type A, peak value) was measured in accordance with JIS K6251-3:2012.

[0245] <Compression set> Using a small test piece for measuring compression set, measurements were taken in accordance with JIS K6262:2013, Method A, at a compression ratio of 25%, a test temperature of 200°C, and a test time of 72 hours.

[0246] In the examples and comparative examples, the following materials were used. Fluorine rubber A: Vinylidene fluoride / hexafluoropropylene molar ratio: 78 / 22 Fluorine content: 66% Mooney Viscosity (ML1+10 (121℃)): 43 Glass transition temperature: -18℃ Heat of fusion: Not observed in second run

[0247] MT Carbon (N2SA:8m 2 / g, DBP: 43ml / 100g) Calcium hydroxide Magnesium oxide Crosslinking accelerator A: a mixture of 91% by mass of benzyldimethyloctadecyl ammonium chloride and 9% by mass of isopropyl alcohol

[0248] Crosslinker-A: 2,2'-bis(trifluoromethyl)-[1,1'-biphenyl]-4,4'-diol (can be synthesized by the method described in JP 2012-62344 A, the σm of the trifluoromethyl group is 0.43, and the σp is 0.54.) Crosslinker-B: Bisphenol AF (σm and σp of hydrogen atoms are both 0.00.) Crosslinker-C: 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (the amino group has a σm of -0.16 and a σp of -0.66.) Crosslinker-D: 2,2',6,6'-tetra-tert-butyl-4,4'-biphenol (the σm of the tert-butyl group is -0.10 and the σp is -0.20). Crosslinker-E: 4,4'-dihydroxybiphenyl (σm and σp of hydrogen atoms are both 0.00.) Crosslinker-F: Octafluoro-4,4'-biphenol (the σm of the fluorine atom is 0.34 and the σp is 0.06, but eight fluorine atoms are directly bonded to the carbon atoms that make up the aromatic ring.) Crosslinker-G: 3,3'-dibromo-4,4'-dihydroxybiphenyl (the σm of the bromine atom is 0.39 and the σp is 0.23, but the bromine atom is directly bonded to a carbon atom that constitutes an aromatic ring.) Crosslinker-H: 2,2'-difluoro-[1,1'-biphenyl]-4,4'-diol (the σm of the fluorine atom is 0.34.) Crosslinker-I: 2,2'-dichloro-[1,1'-biphenyl]-4,4'-diol (σm of chlorine atom is 0.37) Crosslinker-J: 3,3'-difluoro-[1,1'-biphenyl]-4,4'-diol (σp of fluorine atom is 0.06) Crosslinker-K: 4',4-difluoro-[1,1'-biphenyl]-2,2'-diol (the σm of the fluorine atom is 0.34.) Crosslinker-L: 2',4-difluoro-[1,1'-biphenyl]-2,4'-diol (σm of fluorine atom is 0.34) (Enamin)

[0249] <Calculation of the solubility parameter (SP value) of the crosslinking agent> In order to examine the effect of the magnitude of the solubility parameter of the crosslinking agent on the crosslinking properties of the fluororubber crosslinking composition, the solubility parameter of the crosslinking agent was calculated. Here, the solubility parameter (SP) is defined by the regular solution theory introduced by Hildebrand, and is an index that indicates the compatibility of two components. In this disclosure, the value calculated by the following Fedors equation is adopted.

[0250]

number

[0251] <Calculation of the distance between the oxygen atom of the hydroxyl group of the crosslinking agent and the carbon atom of the aromatic ring to which the hydroxyl group is directly bonded (OC bond distance L)> In order to evaluate the crosslinking reactivity of the fluororubber crosslinking composition, the distance (O-C bond distance L) between the oxygen atom of the hydroxyl group of the crosslinking agent and the carbon atom of the aromatic ring to which the hydroxyl group is directly bonded was calculated. The O-C bond distance L was obtained from the molecular structure obtained by structural optimization calculation based on the density functional method. For the structural optimization calculation of the compound, the value calculated by Gaussian16, a quantum chemical calculation program made by Gaussian, was adopted, and B3LYP was used as the density functional and 6-311++g(d,p) was used as the basis function. For compounds with multiple hydroxyl groups, the shortest O-C bond distance L was shown.

[0252] Crosslinker evaluation The components of Example 1 and Comparative Examples 1 to 6 were blended according to the recipe in Table 1, and kneaded on an open roll to prepare a fluororubber crosslinking composition. The maximum torque (MH) and optimal crosslinking time (T90) of the obtained fluororubber crosslinking composition are shown in Table 1. Next, the fluororubber crosslinking composition was 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 a crosslinked sheet (thickness 2 mm) and a small test piece for measuring compression set. The evaluation results of the obtained crosslinked sheet and the results of the compression set test are shown in Table 1.

[0253] [Table 1]

[0254] Tables 2 and 3 show the solubility parameters (SP values) and O-C bond distances L of the crosslinkers used in Example 1 and Comparative Examples 1 to 6. The solubility parameters (SP values) and O-C bond distances L of crosslinkers-H to -K, which have structures similar to that of Example 1, are also shown here.

[0255] [Table 2]

[0256] [Table 3]

[0257] The components of Examples 2 and 3 were blended according to the recipe in Table 4, and kneaded on an open roll to prepare a fluororubber crosslinking composition. The maximum torque (MH) and optimal crosslinking time (T90) of the obtained fluororubber crosslinking composition are shown in Table 4. Next, the fluororubber crosslinking composition was crosslinked by primary crosslinking (press crosslinking) under the conditions shown in Table 4 and secondary crosslinking (oven crosslinking) under the conditions shown in Table 4 to obtain a crosslinked sheet (thickness 2 mm) and a small test piece for measuring compression set. The evaluation results of the obtained crosslinked sheet and the results of the compression set test are shown in Table 4.

[0258] [Table 4]

[0259] Table 5 also shows the solubility parameters (SP values) of the crosslinking agents used in Example 3, and the O-C bond distances L.

[0260] [Table 5]

[0261] The components of Examples 4 and 5 were blended according to the recipe in Table 6, and kneaded on an open roll to prepare a fluororubber crosslinking composition. The maximum torque (MH) and optimal crosslinking time (T90) of the obtained fluororubber crosslinking composition are shown in Table 6. Next, the fluororubber crosslinking composition was crosslinked by primary crosslinking (press crosslinking) under the conditions shown in Table 6 and secondary crosslinking (oven crosslinking) under the conditions shown in Table 6 to obtain a crosslinked sheet (thickness 2 mm) and a small test piece for measuring compression set. The evaluation results of the obtained crosslinked sheet and the results of the compression set test are shown in Table 6.

[0262] [Table 6]

Claims

1. It contains fluororubber (a) and a crosslinking agent (b), and the crosslinking agent (b) is A compound (b1) having a biphenyl ring, two to three hydroxyl groups directly bonded to the carbon atoms constituting the biphenyl ring, and one of the Hammett substituent constants σm and σp being 0.03 or greater, and having one to six substituents (α) directly bonded to the carbon atoms constituting the biphenyl ring (excluding bromine atoms, amino groups, sulfanyl groups, acidic groups, and groups containing these groups), and A salt of compound (b1) with an alkali metal, alkaline earth metal, or onium compound. It is at least one selected from the group consisting of, A fluororubber crosslinking composition wherein the substituent (α) is at least one selected from the group consisting of a perfluoroalkyl group having 1 to 5 carbon atoms, a fluorine atom, a chlorine atom, an alkoxy group having 1 to 5 carbon atoms, an alkoxycarbonyl group having 0 to 5 carbon atoms (excluding the number of carbon atoms constituting the carbonyl group), and an acyl group having 0 to 5 carbon atoms (excluding the number of carbon atoms constituting the carbonyl group).

2. The solubility parameter (SP value) of compound (b1), calculated by Fedors' equation, is 12.1 to 17.8 (cal / cm³). ３ ) １／２ The fluororubber crosslinking composition according to claim 1.

3. The fluororubber crosslinking composition according to claim 1 or 2, wherein the substituent (α) is at least one selected from the group consisting of a trifluoromethyl group, a fluorine atom, and a chlorine atom.

4. The fluororubber crosslinking composition according to claim 1 or 2, wherein the number of hydroxyl groups directly bonded to the carbon atoms constituting the biphenyl ring is 2.

5. The fluororubber crosslinking composition according to claim 1 or 2, wherein the distance between the oxygen atom of the hydroxyl group of compound (b1) and the carbon atom to which the hydroxyl group is directly bonded (O-C bond distance L) is 1.357 to 1.369 Å.

6. The fluororubber crosslinking composition according to claim 1 or 2, wherein the total number of substituents (α) is 2.

7. The fluororubber crosslinking composition according to claim 1 or 2, wherein compound (b1) is a compound represented by general formula (b1-b). 【Chemistry 1】 (In the formula, X １ and X ２ (α) is an independent substituent, and c and d are independent integers from 0 to 3 (where the sum of c and d is an integer of 1 or greater).

8. The fluororubber crosslinking composition according to claim 7, wherein compound (b1) is a compound represented by any one of general formulas (b1-1), (b1-2), and (b1-3). 【Chemistry 2】 【Transformation 3】 【Chemistry 4】 (In each formula, X １ and X ２ (α) is an independent substituent, and c and d are independent integers from 0 to 3 (where the sum of c and d is an integer of 1 or greater).

9. The fluororubber crosslinking composition according to claim 1 or 2, wherein the fluororubber (a) comprises vinylidene fluoride units.

10. The fluororubber crosslinking composition according to claim 1 or 2, wherein the crosslinking agent (b) is contained in an amount of 0.1 to 10 parts by mass per 100 parts by mass of fluororubber (a).

11. The fluororubber crosslinking composition according to claim 1 or 2, further containing a crosslinking accelerator (c), wherein the amount of crosslinking accelerator (c) is 0.1 to 10 parts by mass per 100 parts by mass of fluororubber (a).

12. The fluororubber crosslinking composition according to claim 1 or 2, further comprising an acid acceptor (d), wherein the acid acceptor (d) is at least one selected from the group consisting of metal oxides, metal hydroxides, alkali metal silicates, metal salts of weak acids, and hydrotalcite.

13. The fluororubber crosslinking composition according to claim 1 or 2, further containing an acid acceptor (d), wherein the content of the acid acceptor (d) is 0.1 to 50 parts by mass per 100 parts by mass of fluororubber (a).

14. A molded article obtained from the fluororubber crosslinking composition described in claim 1 or 2.

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