Fluororubber crosslinking composition, molded article and sealing material

Abstract

Provided is a composition for fluorine rubber crosslinking, the composition containing (a) a fluorine rubber that is crosslinkable by a polyol and (b) a crosslinking agent, wherein the crosslinking agent (b) is composed of at least one selected from the group consisting of a compound represented by general formula (b) below and a salt of the compound, an alkali metal, and alkaline earth metal or an onium compound. (The reference symbols are as defined in the specification.)

Description

[Technical Field]

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

[0002] Patent Document 1 describes aromatic polyhydroxy compounds that can act as crosslinkers or co-curing agents for fluorinated elastomers as essential components in the final curable composition. One of the most useful aromatic polyphenols is the bisphenol compound hexafluoroisopropylidene-bis(4-hydroxybenzene), known as bisphenol AF.

[0003] Patent Document 2 describes a composition containing a fluorocarbon elastomer gum, a fluoroaliphatic sulfonamide as a curing agent therefor, and a second curing agent selected from the group consisting of polyhydroxy compounds, polyamine compounds, and derivatives thereof.

[0004] Patent Document 3 describes a composition containing a fluorocarbon elastomer gum and a vulcanizing agent for the same, characterized in that the vulcanizing agent is a composition containing one or a mixture of aromatic compounds having hydroxy and oxyallyl groups directly bonded to a carbon atom of an aromatic ring.

[0005] Patent Document 4 describes a composition for vulcanizing fluororubber, which contains (a) a fluorine-containing elastomer, (b) one or more substances selected from the group consisting of divalent metal oxides, divalent metal hydroxides, and mixtures of these metal oxides or metal hydroxides with metal salts of weak acids, (c) a polyhydroxy aromatic compound, and (d) a specific vulcanization accelerator. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Special Publication No. 64-418 [Patent Document 2] Japanese Patent Application Publication No. 60-215042 [Patent Document 3] Japanese Patent Application Publication No. 59-105046 [Patent Document 4] Japanese Patent Application Publication No. 63-268757 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present disclosure is to provide a composition for cross-linking fluororubber, which contains a compound that does not contain a fluorine atom as a cross-linking agent, and which can give a molded article that is excellent in high-temperature compression set properties, tensile strength, and heat resistance. [Means for solving the problem]

[0008] According to the present disclosure, there is provided a composition for crosslinking fluororubber, which comprises a polyol-crosslinkable fluororubber (a) and a crosslinking agent (b), wherein the crosslinking agent (b) is at least one selected from the group consisting of a compound represented by the following general formula (b) and a salt of the compound with an alkali metal, an alkaline earth metal, or an onium compound:

[0009] [ka] (In the formula, m and n independently represent an integer of 1 to 3. The hydrogen atoms bonded to the four benzene rings may be substituted with any substituent (excluding a hydroxy group, a sulfanyl group, an amino group, an acid group, a halogen atom, and a group containing a halogen atom).)

[0010] In the fluororubber cross-linking composition of the present disclosure, the fluororubber (a) preferably contains vinylidene fluoride units. In the fluororubber cross-linking composition of the present disclosure, the content of the cross-linking agent (b) is preferably 0.5 to 50 mmol per 100 parts by mass of the fluororubber (a). The fluororubber cross-linking composition of the present disclosure preferably further contains a cross-linking accelerator (c). The fluororubber cross-linking composition of the present disclosure preferably further contains an acid acceptor (d). The fluororubber cross-linking composition of the present disclosure preferably further contains 0.1 to 50 parts by mass of an acid acceptor (d) relative to 100 parts by mass of the fluororubber (a). The fluororubber cross-linking composition of the present disclosure preferably further contains at least one acid acceptor (d) selected from the group consisting of metal oxides, metal hydroxides, alkali metal silicates, metal salts of weak acids, and hydrotalcites.

[0011] In the fluororubber cross-linking composition of the present disclosure, the cross-linking agent (b) is preferably at least one selected from the group consisting of compounds represented by the following formula (b1) and salts of the compounds with alkali metals, alkaline earth metals, or onium compounds:

[0012] [ka]

[0013] The present disclosure also provides a molded article or a sealing material obtained from the above-mentioned fluororubber cross-linking composition. [Effects of the Invention]

[0014] According to the present disclosure, it is possible to provide a fluororubber cross-linking composition that contains a compound that does not contain a fluorine atom as a cross-linking agent, and that can give a molded product that is excellent in high-temperature compression set properties, tensile strength, and heat resistance. DETAILED DESCRIPTION OF THE INVENTION

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

[0016] The fluororubber cross-linking composition of the present disclosure contains a polyol-cross-linkable fluororubber (a) and a cross-linking agent (b).

[0017] By using a crosslinkable composition containing bisphenol AF as a crosslinking agent, molded articles with excellent compression set properties at high temperatures can be obtained. However, since bisphenol AF is a compound containing fluorine atoms, if bisphenol AF adheres to equipment used for measuring or preparing the composition, a dedicated incineration device is required to dispose of the waste generated by cleaning the bisphenol AF adhered to the equipment, which results in a significant cost burden. Therefore, there is a demand for a compound that does not contain fluorine atoms and that can give molded articles with excellent compression set properties at high temperatures, to be used as a polyol crosslinking agent.

[0018] The fluororubber cross-linking composition of the present disclosure contains a compound having the structure described below as a cross-linking agent. These compounds are easy to handle because they do not contain fluorine atoms. Furthermore, molded articles obtained from the fluororubber cross-linking composition of the present disclosure have excellent compression set properties and tensile strength at high temperatures, and also have excellent heat resistance, such as being less susceptible to change in tensile strength even when the molded article is exposed to high temperatures.

[0019] Hereinafter, each component of the fluororubber cross-linking composition of the present disclosure will be described.

[0020] (a) Polyol-crosslinkable fluororubber The polyol-crosslinkable fluoroelastomer used in this disclosure is a fluoroelastomer having a polyol-crosslinkable site. In this disclosure, the fluoroelastomer is an amorphous fluoropolymer. "Amorphous" means that the magnitude of the melting peak (ΔH) appearing in differential scanning calorimetry (DSC) (heating rate 20°C / min) or differential thermal analysis (DTA) (heating rate 20°C / min) of the fluoropolymer is 4.5 J / g or less. Fluoroelastomers exhibit elastomeric properties upon crosslinking. Elastomeric properties refer to the ability of a polymer to be stretched and to retain its original length when the force required to stretch the polymer is no longer applied.

[0021] Examples of the polyol-crosslinkable moiety include a moiety having a vinylidene fluoride (VdF) unit. Among them, fluororubbers containing VdF units are preferred because the effect of using the crosslinking agent (b) is easily exhibited. Examples of fluororubbers having a polyol-crosslinkable moiety 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 JP-A-2018-527449; 100 parts (phr) of a cured fluoroelastomer having a low fluorine content of less than 67% by weight as described in JP-A-7-316377, which contains 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.

[0022] Examples of fluororubbers having a polyol crosslinkable site include non-perfluoro fluororubbers and fluororubbers containing -CH2- (methylene group) in the main chain.

[0023] Examples of fluororubbers having polyol-crosslinkable moieties include VdF-based fluororubbers and rubbers having polyol-crosslinkable functional moieties such as double bonds in the side chains and / or main chains. Examples of VdF-based fluororubbers include tetrafluoroethylene (TFE) / propylene / VdF-based fluororubbers, ethylene / hexafluoropropylene (HFP) / VdF-based fluororubbers, VdF / HFP-based fluororubbers, and VdF / TFE / HFP-based fluororubbers. These fluororubbers having polyol-crosslinkable moieties can be used alone or in any combination within the scope that does not impair the effects of the present disclosure.

[0024] The VdF-based fluororubber is preferably one represented by the following general formula (1).

[0025] -(M 1 )-(M 2 )-(N 1 )- (1) (Wherein, structural unit M 1 is vinylidene fluoride (m 1 ) is a structural unit derived from the structural unit M 2 is a fluorine-containing ethylenic monomer (m 2 ) is a structural unit derived from the structural unit N 1 is the monomer (m 1 ) and monomer (m 2 ) and copolymerizable monomers (n 1 ) is a repeating unit derived from

[0026] Among the VdF-based fluororubbers represented by the general formula (1), the structural unit M 1 30 to 85 mol % of the structural unit M 2 It is preferable that the structural unit M 1 50 to 80 mol % of the structural unit M 2 The structural unit N is 50 to 20 mol %. 1 is the structural unit M 1 and structural unit M 2 It is preferably 0 to 20 mol % based on the total amount of the above.

[0027] 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 is satisfied)), a fluorine-containing monomer represented by general formula (3): CHX 11 =CX 12 Rf<00\00030>(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), fluorine-containing monomers such as vinyl fluoride can be mentioned. Among these, TFE, HFP, and PAVE are preferred.

[0028] <00001\87>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 that provides a crosslinking site, a bisolefin compound, etc. can be mentioned. These can be used alone or in any combination.

[0029] Examples of the monomer that provides such a crosslinking site include those represented by the general formula (4): CY 1 2=CY 1 -Rf 5 CHR 1 X 1 (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 1 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 2 (5) (wherein m is an integer of 0 to 5, n is an integer of 1 to 3, X 2 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 examples thereof include 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. Examples of suitable monomers include iodine-containing monomers such as 4-iodo-3,3,4,4-tetrafluoro-1-butene described in JP-A-61-55138, bromine-containing monomers described in JP-A-4-505341, and cyano group-containing monomers, carboxyl group-containing monomers, and alkoxycarbonyl group-containing monomers described in JP-A-4-505345 and JP-A-5-500070. These may be used alone or in any combination. As the bisolefin compound, those described in JP-A-8-12726 can be used.

[0030] 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.

[0031] Among these, the polyol-crosslinkable 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.

[0032] The fluororubber preferably has a Mooney viscosity at 121°C (ML1+10(121°C)) of 1 or more, more preferably 3 or more, even more preferably 5 or more, and particularly preferably 10 or more. The Mooney viscosity is preferably 200 or less, more preferably 170 or less, even more preferably 150 or less, even more preferably 130 or less, and particularly preferably 100 or less. The Mooney viscosity is measured in accordance with ASTM D1646-15 and JIS K6300-1:2013.

[0033] The fluorine content of the fluororubber is preferably 50 to 75 mass%, more preferably 60 to 73 mass%, and even more preferably 63 to 72 mass%. The fluorine content is calculated from the composition ratio of the monomer units that make up the fluororubber.

[0034] The fluororubber preferably has a glass transition temperature of −50 to 0° C. The glass transition temperature can be determined by obtaining a DSC curve using a differential scanning calorimeter by heating 10 mg of a sample at a rate of 20° C. / min, and determining the glass transition temperature as the temperature at the intersection between an extension of the baseline before and after the second-order transition of the DSC curve and a tangent to the inflection point of the DSC curve.

[0035] The fluororubber described above can be produced by a conventional method.

[0036] (b) Crosslinking agent The fluororubber crosslinking composition of the present disclosure contains a crosslinking agent, which is at least one selected from the group consisting of compounds represented by the following general formula (b) and salts of the above compounds with alkali metals, alkaline earth metals, or onium compounds:

[0037] [ka] (In the formula, m and n independently represent an integer of 1 to 3. The hydrogen atoms bonded to the four benzene rings may be substituted with any substituent (excluding a hydroxy group, a sulfanyl group, an amino group, an acid group, a halogen atom, and a group containing a halogen atom).)

[0038] The compound represented by general formula (b) contains a fluorene ring, and at least one hydroxy group is bonded to each of the two benzene rings bonded to the 9-position of the fluorene ring. The number of hydroxy groups bonded to the two benzene rings can be selected from 2 to 6, and the bonding position of the hydroxy group is not limited. m and n represent the number of hydroxy groups bonded to each of the two benzene rings bonded to the 9-position of the fluorene ring. m and n may, for example, independently be 1 or 2. In this case, for example, two hydroxy groups may be bonded to each of the para positions of the two benzene rings, or four hydroxy groups may be bonded to each of the meta and para positions of the two benzene rings. The above m and n are preferably integers of 1 to 2, and more preferably 1. Furthermore, having a hydroxy group at the para position of the benzene ring is preferred in terms of crosslinking properties and good tensile strength and compression set properties of molded articles.

[0039] Of the hydrogen atoms bonded to the fluorene ring and the two benzene rings, the hydrogen atoms not substituted with hydroxy groups may be substituted with a substituent other than a hydroxy group, a sulfanyl group, an amino group, an acid group, a halogen atom, or a group containing a halogen atom, or may be unsubstituted. Examples of the substituent include a cyano group and an alkyl group having 1 to 10 carbon atoms. The substituent is a substituent that does not contain a halogen atom, such as a fluorine atom or a group containing a fluorine atom, and therefore the compound represented by general formula (b) does not contain a fluorine atom.

[0040] 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 salt group in which this hydrogen atom has been replaced with another atom (such as an alkali metal atom). An example of an 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 acid groups are a carboxy group, a sulfo group, a sulfino group, a phosphate group, a phosphonate group, and the acid salt groups thereof.

[0041] The crosslinking agent may be a salt of a compound represented by general formula (b) with an alkali metal, a salt of a compound represented by general formula (b) with an alkaline earth metal, or a salt of a compound represented by general formula (b) with an onium compound. Among these salts, a salt of a compound represented by general formula (b) with an onium compound is preferred. The salt of the compound with an onium compound is an onium salt composed of an anion moiety derived from the compound and a cation moiety derived from the onium compound. By using an onium salt as the crosslinking agent (b), the onium salt not only acts as a crosslinking agent but also as a crosslinking accelerator.

[0042] The compound represented by general formula (b), the salt of the compound represented by general formula (b) with an alkali metal, the salt of the compound represented by general formula (b) with an alkaline earth metal, or the salt of the compound represented by general formula (b) with an onium compound can be used either alone or in combination.

[0043] The salt of the compound represented by general formula (b) with an onium compound can be obtained by reacting the compound represented by general formula (b) with an alkaline substance such as sodium hydroxide in water or an organic solvent, or with metallic sodium in an organic solvent, followed by further reaction with an onium compound such as benzyltriphenylphosphonium chloride, and then distilling off the water or organic solvent. During the reaction, the solution of the reaction product can be filtered, or the reaction product can be washed with water or an organic solvent, if necessary, to remove by-products such as sodium chloride.

[0044] The alkali metal is preferably Na or K. The alkaline earth metal is preferably Ca or Mg.

[0045] Examples of the onium salt include ammonium salts, phosphonium salts, and sulfonium salts.

[0046] Examples of onium compounds that constitute onium salts include ammonium compounds, phosphonium compounds, sulfonium compounds, etc. In the present disclosure, the onium compound does not contain a fluorine atom.

[0047] The onium compound constituting the onium salt is preferably an ammonium compound or a phosphonium compound, more preferably a phosphonium compound, even more preferably a quaternary phosphonium compound, and particularly preferably benzyltriphenylphosphonium. The ammonium compound is preferably a quaternary ammonium compound, and more preferably 8-benzyl-1,8-diazabicyclo[5,4,0]-7-undecenium or benzyldimethyloctadecylammonium.

[0048] The crosslinking agent is preferably at least one selected from the group consisting of compounds represented by the following formula (b1) and salts of the above compounds with alkali metals, alkaline earth metals or onium compounds.

[0049] [ka]

[0050] The crosslinking agent can be used in combination with other compounds. Examples of the mixture containing the crosslinking agent include a mixture of a solid solution of the crosslinking agent and a crosslinking accelerator, and a mixture of the crosslinking agent and a compound capable of dissolving it. The mixture of the crosslinking agent and the crosslinking accelerator is preferably a mixture of the compound represented by general formula (b) and a quaternary phosphonium salt, or a mixture of the compound represented by general formula (b) and a quaternary ammonium salt, more preferably a mixture of the compound represented by general formula (b) and a quaternary phosphonium salt, and even more preferably a mixture of the compound represented by general formula (b) and benzyltriphenylphosphonium chloride.

[0051] The content of the crosslinking agent is preferably 0.5 to 50 mmol, more preferably 1.0 mmol or more, even more preferably 2.0 mmol or more, more preferably 40 mmol or less, even more preferably 30 mmol or less, and particularly preferably 20 mmol or less, relative to 100 parts by mass of the polyol-crosslinkable fluororubber, since this allows for the production of a molded product with even better tensile strength and compression set properties at high temperatures.

[0052] (c) Crosslinking accelerator The fluororubber crosslinking composition of the present disclosure may further contain a crosslinking accelerator. The use of a crosslinking accelerator can accelerate the crosslinking reaction by accelerating the formation of intramolecular double bonds in the dehydrofluorination reaction of the fluororubber main chain. When a compound represented by general formula (b) is used as the crosslinking agent, it is preferable to use a crosslinking accelerator together with the crosslinking agent. When an onium salt is used as the crosslinking agent, a crosslinking accelerator can be used together with the crosslinking agent, but it is not necessarily required. The amount of crosslinking accelerator can be adjusted appropriately depending on the crosslinking conditions and the physical properties of the molded product. Increasing the amount of crosslinking accelerator speeds up the crosslinking reaction or enables crosslinking at a lower temperature, but tends to worsen the compression set properties. Conversely, reducing the amount of crosslinking accelerator slows down the crosslinking reaction, but tends to improve the compression set properties.

[0053] As a crosslinking accelerator for a polyol crosslinking system, an onium salt (excluding salts of a compound represented by general formula (b) and an onium compound) is generally used. The onium salt is not particularly limited, and examples thereof include ammonium salts such as quaternary ammonium salts, phosphonium salts such as quaternary phosphonium salts, and sulfonium salts, with quaternary ammonium salts and quaternary phosphonium salts being preferred.

[0054] 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 1,8-diazabicyclo[5,4,0]-7-undecenium chloride, 8-tetracosyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, 8-benzyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride (hereinafter referred to as DBU-B), 8-benzyl-1,8-diazabicyclo[5,4,0]-7-undecenium hydroxide, 8-phenethyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, 8-(3-phenylpropyl)-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, benzyldimethyloctadecylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium chloride, benzyltributylammonium chloride, benzyltriethylammonium chloride, tetrabutylammonium hydrogen sulfate, tetrabutylammonium hydroxide, and the like. Among these, DBU-B or benzyldimethyloctadecylammonium chloride is preferred from the viewpoint of crosslinkability and physical properties of the crosslinked product.

[0055] Furthermore, the quaternary phosphonium salt is not particularly limited, and examples thereof include tetrabutylphosphonium chloride, benzyltriphenylphosphonium chloride (hereinafter referred to as BTPPC), benzyltrimethylphosphonium chloride, benzyltributylphosphonium chloride, tributylallylphosphonium chloride, tributyl-2-methoxypropylphosphonium chloride, and benzylphenyl(dimethylamino)phosphonium chloride. Among these, benzyltriphenylphosphonium chloride (BTPPC) is preferred from the viewpoints of crosslinkability and the physical properties of the crosslinked product.

[0056] The content of the crosslinking accelerator is preferably 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, still more preferably 0.1 to 3 parts by mass, and particularly preferably 0.1 to 2 parts by mass, relative to 100 parts by mass of the polyol-crosslinkable fluororubber, because the crosslinking reaction proceeds at an appropriate rate and a molded product with better compression set properties at high temperatures can be obtained. When the crosslinking agent is a salt of a compound represented by general formula (b) and an onium compound, the content of the crosslinking accelerator is a value including the mass of the cation portion of the crosslinking agent (i.e., the cation derived from the onium compound).

[0057] (d) Acid acceptor The fluororubber cross-linking composition of the present disclosure may further contain an acid acceptor. By containing an acid acceptor, the cross-linking reaction of the fluororubber cross-linking composition proceeds more smoothly, and the tensile strength and the compression set properties at high temperatures are further improved.

[0058] Examples of the acid acceptor include metal oxides such as magnesium oxide, calcium oxide, and bismuth oxide, metal hydroxides such as calcium hydroxide, alkali metal silicates such as hydrotalcite and sodium metasilicate described in JP-A-2011-522921, 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.

[0059] As the acid acceptor, at least one selected from the group consisting of metal oxides, metal hydroxides, alkali metal silicates, metal salts of weak acids, and hydrotalcite is preferred, as this allows for the production of molded articles with even better compression set properties at high temperatures, and sodium metasilicate hydrate, calcium hydroxide, magnesium oxide, bismuth oxide, and hydrotalcite are more preferred. Furthermore, when the resulting molded article requires good water resistance, acid resistance, or resistance to organic acid esters including biodiesel, at least one selected from the group consisting of bismuth oxide and hydrotalcite is preferred.

[0060] 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 polyol-crosslinkable fluororubber, since a molded product with better tensile strength and compression set properties at high temperatures can be obtained.

[0061] Increasing the content of the acid acceptor tends to decrease the water resistance, acid resistance, and resistance to organic acid esters, including biodiesel, of the resulting molded article. Conversely, decreasing the content of the acid acceptor tends to decrease the crosslinking rate and the mechanical properties due to a decrease in crosslink density. Therefore, the content of the acid acceptor can be selected depending on the intended use of the resulting molded article. Furthermore, when an acid acceptor other than calcium hydroxide is contained, reducing the content of calcium hydroxide to 0 to 1.5 parts by mass, for example, and then adjusting the content of the other acid acceptor to adjust the crosslink density can result in a molded article with even better compression set properties at high temperatures.

[0062] (e) Other ingredients The fluororubber cross-linking composition may optionally contain various additives commonly used in fluororubber cross-linking compositions, such as fillers (carbon black, bituminous coal, barium sulfate, diatomaceous earth, calcined clay, talc, wollastonite, carbon nanotubes, etc.), processing aids, colorants, stabilizers, tackifiers (coumarone resin, coumarone-indene resin, etc.), electrical conductivity imparting agents, thermal conductivity imparting agents, surface anti-tack agents, flexibility imparting agents, heat resistance improvers, flame retardants, foaming agents, and antioxidants described in International Publication No. 2012 / 023485. It may also contain one or more commonly used cross-linking agents and cross-linking accelerators other than those described above. Among these, thermal carbon black and furnace carbon black are preferred as carbon black, with MT carbon black, FT carbon black, and SRF carbon black being more preferred. The use of carbon black with a relatively large particle size, such as FT carbon black, results in molded articles with excellent compression set properties, while the use of carbon black with a finer particle size results in molded articles with excellent strength and elongation. By combining different grades, the above properties can be balanced.

[0063] The processing aids include plasticizers and mold release agents, and are not particularly limited, but may include, for example, synthetic fatty acid esters, waxes containing natural fatty acid esters, aliphatic amines such as stearylamine, fatty acid amides such as stearic acid amide, aliphatic alcohols, synthetic waxes such as polyethylene wax, phosphate esters such as tricresyl phosphate, silicone-based processing aids, etc., and blending two or more types in appropriate amounts as needed can improve the balance between mold releasability during molding and the physical properties of the molded product. The processing aids may be blended within a range that does not impair the effects of the present disclosure.

[0064] The content of the filler such as carbon black is not particularly limited, but is preferably 0 to 300 parts by mass, more preferably 1 to 150 parts by mass, even more preferably 2 to 100 parts by mass, and particularly preferably 2 to 75 parts by mass, relative to 100 parts by mass of the polyol-crosslinkable fluororubber.

[0065] The content of processing aids such as wax is preferably 0 to 10 parts by mass, more preferably 0 to 5 parts by mass, per 100 parts by mass of polyol-crosslinkable fluororubber. When processing aids, plasticizers, or release agents are used, the mechanical properties and sealing properties of the resulting molded article tend to deteriorate, so it is necessary to adjust the content of these agents within a range that allows the desired properties of the resulting molded article.

[0066] The fluororubber cross-linking composition may contain a dialkyl sulfone compound. The inclusion of a dialkyl sulfone compound increases the cross-linking efficiency of the fluororubber cross-linking composition, accelerates the cross-linking rate, further improves the compression set properties, and improves the fluidity of the rubber material. Examples of dialkyl sulfone compounds include dimethyl sulfone, diethyl sulfone, dibutyl sulfone, methyl ethyl sulfone, diphenyl sulfone, and sulfolane. Among these, sulfolane is preferred from the viewpoints of cross-linking efficiency and compression set properties, as well as its suitable boiling point. The content of the dialkyl sulfone compound is preferably 0 to 10 parts by mass, more preferably 0 to 5 parts by mass, and particularly preferably 0 to 3 parts by mass, per 100 parts by mass of the fluororubber. When the fluororubber cross-linking composition of the present disclosure contains a dialkyl sulfone compound, the lower limit of the content of the dialkyl sulfone compound may be, for example, 0.1 parts by mass or more per 100 parts by mass of the fluororubber.

[0067] The dialkyl sulfone compound and the processing aid may be blended together, as this provides a good balance of crosslinking rate, flowability of the rubber material during molding, mold releasability during molding, and mechanical properties of the molded product.

[0068] The fluororubber cross-linking composition can be obtained by kneading the fluororubber (a), the cross-linking agent (b), the cross-linking accelerator (c), the acid acceptor (d), and other components (e) using a commonly used rubber kneading device, such as a roll, kneader, Banbury mixer, internal mixer, or twin-screw extruder.

[0069] In order to uniformly disperse each component in the rubber, a method may be used in which the fluororubber (a), crosslinking agent (b) and crosslinking accelerator (c) are kneaded while melting them at a high temperature of 100 to 200°C using a closed kneading device such as a kneader, and then the acid acceptor (d) and other components (e) are kneaded at a relatively low temperature below this temperature.

[0070] Furthermore, the dispersibility can be further improved by mixing the fluororubber (a), crosslinking agent (b), crosslinking accelerator (c), acid acceptor (d), other components (e), etc., leaving the mixture at room temperature for 12 hours or more, and then mixing it again.

[0071] <Molded products> The molded article of the present disclosure can be obtained by crosslinking the fluororubber crosslinking composition. Alternatively, the molded article of the present disclosure can 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 employed. The order of molding and crosslinking is not limited, and molding may be followed by crosslinking, crosslinking may be followed by molding, or molding and crosslinking may be performed simultaneously.

[0072] Examples of molding methods include, but are not limited to, compression molding, casting, injection molding, extrusion molding, and rotocure molding. Examples of crosslinking methods that can be used include steam crosslinking, heat crosslinking, and radiation crosslinking, with steam crosslinking and heat crosslinking being preferred. Specific crosslinking conditions, which are not limited to, are typically a temperature range of 140 to 250°C, a crosslinking time of 1 minute to 24 hours, and can be determined appropriately depending on the types of crosslinking agent (b), crosslinking accelerator (c), and acid acceptor (d).

[0073] Furthermore, by heating the obtained molded article in an oven or the like, it is possible to improve mechanical properties such as tensile strength, heat resistance, and high-temperature compression set properties, etc. Specific crosslinking conditions, which are not limited to any particular conditions, are usually in the temperature range of 140 to 300°C and the time range of 30 minutes to 72 hours, and may be appropriately determined depending on the types of crosslinking agent (b), crosslinking accelerator (c), acid acceptor (d), etc.

[0074] The molded article of the present disclosure has excellent properties such as heat resistance, oil resistance, chemical resistance, and flexibility, and further has excellent compression set properties at high temperatures. Therefore, the molded article of the present disclosure is generally used in areas that come into contact with other materials and slide, seal or seal other materials or substances, or are intended for vibration and sound insulation, and can be used as various parts in various fields such as the automotive industry, aircraft industry, and semiconductor industry. In particular, the molded article of the present disclosure has excellent compression set properties at high temperatures, making it suitable for use as a sealing material.

[0075] Examples of fields in which they are used include semiconductor-related fields, automobiles, aircraft, space and rockets, ships, chemicals such as chemical plants, pharmaceuticals such as medicines, photography such as developing machines, printing such as printing machines, painting such as painting equipment, analytical and physicochemical machinery such as analytical instruments and meters, food equipment including food plant equipment and household goods, food beverage manufacturing equipment, pharmaceutical manufacturing equipment, medical parts, chemical transport equipment, nuclear power plant equipment, steel such as iron plate processing equipment, general industry, electricity, fuel cells, electronic parts, optical equipment parts, space equipment parts, petrochemical plant equipment, energy resource exploration and mining equipment parts such as oil and gas, oil refining, and oil transportation equipment parts.

[0076] Examples of uses of the molded articles include various sealing materials and packings such as rings, packings, gaskets, diaphragms, oil seals, bearing seals, lip seals, plunger seals, door seals, lip and face seals, gas delivery plate seals, wafer support seals, barrel seals, etc. As sealing materials, they can be used in applications requiring heat resistance, solvent resistance, chemical resistance, and non-stickiness.

[0077] It can also be used as a tube, hose, roll, various rubber rolls, flexible joint, rubber plate, coating, belt, damper, valve, valve seat, valve body, chemical-resistant coating material, laminating material, lining material, etc.

[0078] The cross-sectional shape of the ring, packing, and seal may be of various shapes, specifically, for example, square, O-shaped, ferrule-shaped, or irregular shapes such as D-shaped, L-shaped, T-shaped, V-shaped, X-shaped, and Y-shaped.

[0079] In the semiconductor-related fields, the present invention can be used, for example, in semiconductor manufacturing equipment, liquid crystal panel manufacturing equipment, plasma panel manufacturing equipment, plasma display panel manufacturing equipment, plasma addressed liquid crystal panel manufacturing equipment, organic EL panel manufacturing equipment, field emission display panel manufacturing equipment, solar cell substrate manufacturing equipment, semiconductor conveying equipment, etc. Examples of such equipment include CVD equipment, gas control equipment such as semiconductor gas control equipment, dry etching equipment, wet etching equipment, plasma etching equipment, reactive ion etching equipment, reactive ion beam etching equipment, sputter etching equipment, ion beam etching equipment, oxidation diffusion equipment, sputtering equipment, ashing equipment, plasma ashing equipment, cleaning equipment, ion implantation equipment, plasma CVD equipment, exhaust equipment, exposure equipment, polishing equipment, film formation equipment, dry etching cleaning equipment, UV / O3 cleaning equipment, ion beam cleaning equipment, laser beam cleaning equipment, plasma cleaning equipment, and gas etching cleaning equipment. 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, and fluorine plasma treatment, heat treatment film formation equipment, wafer transport equipment, wafer cleaning equipment, silicon wafer cleaning equipment, silicon wafer processing equipment, equipment used in LP-CVD processes, equipment used in lamp annealing processes, and equipment used in reflow processes.

[0080] Specific uses in the semiconductor-related field include, for example, various sealing materials such as O-rings and gaskets for gate valves, quartz windows, chambers, chamber lits, gates, bell jars, couplings, and pumps; various sealing materials such as O-rings for resist developer and stripper solutions, hoses and tubes; linings and coatings for resist developer tanks, stripper tanks, wafer cleaning solution tanks, and wet etching tanks; pump diaphragms; rolls for transporting wafers; hose tubes for wafer cleaning solutions; sealing materials for clean facilities such as sealants for clean rooms and other clean facilities; sealing materials for storage cabinets for storing semiconductor manufacturing equipment and devices such as wafers; and diaphragms for transporting chemical solutions used in the semiconductor manufacturing process.

[0081] In the above-mentioned automotive field, it can be used in the engine body, main driving system, valve train system, lubrication and cooling system, fuel system, intake and exhaust system, transmission system of the drive system, steering system of the chassis, brake system, basic electrical parts, control system electrical parts, equipment electrical parts, etc. The above-mentioned automotive field also includes motorcycles.

[0082] In the engine main body and its peripheral devices as described above, molded products can be used for various sealing materials that require heat resistance, oil resistance, fuel oil resistance, engine cooling antifreeze resistance, and steam resistance. Examples of such sealing materials include seals such as gaskets, shaft seals, and valve stem seals; non-contact or contact type packings such as self-sealing packings, piston rings, split ring 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.

[0083] 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 regulating valves, 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, fuel pump oil seals, fuel sender seals, fuel tank rollover valve seals, filler seals, injector seals, filler cap seals, filler cap valve seals; fuel hoses, Hoses such as fuel supply hoses, fuel return hoses, vapor (evaporative) hoses, vent (breather) hoses, filler hoses, filler neck hoses, hoses inside fuel tanks (in-tank hoses), carburetor control hoses, fuel inlet hoses, and fuel breather hoses; gaskets used in fuel filters and fuel line connector systems, and flange gaskets used in carburetors; line materials such as vapor recovery lines, fuel feed lines, and vapor / ORVR lines; diaphragms used in canisters, ORVRs, fuel pumps, fuel tank pressure sensors, gasoline pumps, carburetor sensors, composite air control units (CACs), pulsation dampers, canister and autocock diaphragms, and pressure regulator diaphragms for fuel injection systems; fuel pump valves, carburetor needle valves, rollover check valves, and check valves; vents (breathers), tubes used inside fuel tanks; tank packings for fuel tanks, and packings for carburetor acceleration pump pistons; vibration-damping parts for fuel tank fuel senders;These include 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 composite air control systems (CAC), fuel tank bodies, and sealing parts for solenoid valves.

[0084] 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, and O-rings and grommets for anti-lock braking systems (ABS).

[0085] Specific examples of uses of the basic electrical components include insulators and sheaths for electrical wires (harnesses), tubes for harness exterior parts, and grommets for connectors.

[0086] Specific examples of applications in electrical control components include coating materials for various sensor wires.

[0087] Specific examples of applications for the above-mentioned electrical equipment parts include O-rings and packings for car air conditioners, cooler hoses, high-pressure air conditioner hoses, air conditioner hoses, gaskets for electronic throttle units, plug boots for direct ignition, and distributor diaphragms. They can also be used to bond electrical parts.

[0088] Specific uses in the intake and exhaust systems include packings used in intake manifolds, exhaust manifolds, etc., and throttle body packing for throttles; diaphragms used in EGR (exhaust gas recirculation), pressure control (BPT), wastegates, turbo wastegate actuators, variable turbine geometry (VTG) turbo actuators, and exhaust purification valves; 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 compressor of turbo engines equipped with intercoolers, exhaust gas hoses, air intake hoses, turbo hoses, and DPF (diesel particulate filter) sensor hoses; air ducts and turbo air ducts; intake manifold gaskets; EGR seals, 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.

[0089] Other applications include seals for vapor recovery canisters, catalytic converters, exhaust gas sensors, oxygen sensors, vapor recovery and vapor canister solenoid armatures, and intake manifold gaskets in emission control components.

[0090] It can also be used in diesel engine parts such as O-ring seals for direct injection injectors, rotary pump seals, control diaphragms, fuel hoses, EGR, priming pumps, and boost compensator diaphragms, as well as O-rings, seals, hoses, tubes, diaphragms, gasket materials, and pipes used in urea SCR systems, as well as the urea water tank body and seals for the urea water tank.

[0091] Specific examples of applications in the transmission system include transmission-related bearing seals, oil seals, O-rings, packing, torque converter hoses, etc. Also included are transmission oil seals, AT transmission oil hoses, ATF hoses, O-rings, packing, etc.

[0092] Transmissions include AT (automatic transmission), MT (manual transmission), CVT (continuously variable transmission), and DCT (dual clutch transmission).

[0093] 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).

[0094] Specific examples of uses in steering systems include power steering oil hoses and high-pressure power steering hoses.

[0095] Examples of forms used in the engine body of an automobile engine include gaskets such as cylinder head gaskets, cylinder head cover gaskets, oil pan packings, and general gaskets, seals such as O-rings, packings, and timing belt cover gaskets, hoses such as control hoses, vibration-isolating rubber for engine mounts, control valve diaphragms, and camshaft oil seals.

[0096] In the main driving system of an automobile engine, it can be used as a shaft seal such as a crankshaft seal or a camshaft seal.

[0097] 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.

[0098] In the lubrication and cooling systems of automobile engines, it can be used for engine oil cooler hoses, oil return hoses, seal gaskets for engine oil coolers, water hoses around radiators, radiator seals, radiator gaskets, radiator O-rings, vacuum pump oil hoses for vacuum pumps, as well as radiator hoses, radiator tanks, oil pressure diaphragms, fan coupling seals, etc.

[0099] 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, sulfur oxide sensor seals, temperature sensor seals, temperature sensor bushings, diesel particle filter sensor seals, diesel particle filter sensor bushings, injector O-rings, injector packings, fuel pump O-rings and diaphragms, gearbox seals, power piston packings, cylinder liner seals, valve stem seals, static valve stem seals, dynamic valve stem seals, automatic transmission front pump seals, rear axle pinion seals, universal joint gaskets, speedometer pinion seals, foot brake piston cups, torque transmission O-rings and oil seals, exhaust gas re-burner seals and bearing seals, re-burner hoses, Carburetor sensor diaphragms, anti-vibration rubber (engine mounts, exhaust parts, muffler hangers, suspension bushings, center bearings, strut bumper rubber, etc.), anti-vibration rubber for suspensions (strut mounts, bushings, etc.), anti-vibration rubber for drivetrains (dampers, etc.), fuel hoses, EGR tubes and hoses, twin carburetor tubes, carburetor needle valve core valves, carburetor flange gaskets, oil hoses, oil cooler hoses, ATF hoses, cylinder head gaskets, water pump seals, gearbox seals, needle valve tips, motorcycle reed valve leads, automobile engine oil seals, gasoline hose gun seals, car air conditioner seals, rubber hoses for engine intercoolers, fuel line connector devicesSeals for engine systems, CAC valves, needle tips, engine wiring, filler hoses, car air conditioner O-rings, intake gaskets, fuel tank materials, distributor diaphragms, water hoses, clutch hoses, PS hoses, AT hoses, master back hoses, heater hoses, air conditioning hoses, ventilation hoses, oil filler caps, PS rack seals, rack and pinion boots, CVJ boots, ball joint dust covers, strut dust covers, weather strips, glass runs, center unit gaskets, body site welts, bumper rubber, door latches, dash insulators, high tension cords, flat belts, poly V-belts, timing belts, toothed belts, V-ribbed belts, tires, wiper blades, diaphragms and plungers for LPG vehicle regulators, diaphragms and valves for CNG vehicle regulators DME-compatible rubber parts, auto-tensioner diaphragms and boots, idle speed control diaphragms and valves, auto speed control actuators, vacuum pump diaphragms, check valves and plungers, 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 tire vulcanization molding.

[0100] In the above-mentioned aircraft, space and rocket, and ship fields, it can be used particularly in fuel systems and lubricating oil systems.

[0101] In the aircraft field, the composition can be used, for example, as various sealing parts for aircraft, various aircraft parts for aircraft engine oil applications, jet engine valve stem seals, gaskets and O-rings, rotating shaft seals, gaskets for hydraulic equipment, firewall seals, fuel supply hoses, gaskets and O-rings, aircraft cables, oil seals and shaft seals, etc.

[0102] 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 gas turbine engine oil, and vibration isolation pads for missile ground control.

[0103] In addition, in the marine field, the material can be used, for example, as a stern seal for a screw propeller shaft, an intake and exhaust valve stem seal for a diesel engine, a valve seal for a butterfly valve, a valve seat or shaft seal for a butterfly valve, a shaft seal for a butterfly valve, a stern tube seal, a fuel hose, a gasket, an O-ring for an engine, a cable for a ship, an oil seal for a ship, a shaft seal for a ship, etc.

[0104] In the chemical field such as the above-mentioned chemical plants and the chemical field such as pharmaceuticals, the material can be used in processes that require high chemical resistance, for example, processes for producing chemical products such as pharmaceuticals, agricultural chemicals, paints, and resins.

[0105] Specific uses in the chemical and pharmaceutical fields include chemical equipment, chemical pumps and flow meters, chemical piping, heat exchangers, pesticide sprayers, pesticide transfer pumps, gas piping, fuel cells, analytical equipment and physical and chemical equipment (for example, column fittings for analytical equipment and instruments), shrink joints for flue gas desulfurization equipment, nitric acid plants, seals used in power plant turbines, etc., seals used in medical sterilization processes, seals for plating solutions, roller seals for papermaking belts, and 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, and O-rings for compressor sealing; packing used in high-temperature vacuum dryers, tube joints for gas chromatography and pH meters, etc., and glass cooling seals for sulfuric acid manufacturing equipment. Examples of suitable applications include: instrument packing; diaphragms used in diaphragm pumps, analytical equipment, and physicochemical equipment; gaskets used in analytical equipment and meters; ferrules used in analytical equipment and meters; valve seats; U-cups; linings used in chemical equipment, gasoline tanks, wind tunnels, etc., and corrosion-resistant linings for anodized aluminum tanks; coatings for plating masking jigs; valve parts for analytical equipment and physicochemical equipment; expansion joints for flue gas desulfurization plants; acid-resistant hoses for concentrated sulfuric acid, etc., chlorine gas transfer hoses, oil-resistant hoses, and rainwater drain hoses for benzene and toluene storage tanks; chemical-resistant tubing and medical tubing used in analytical equipment 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.

[0106] In the photographic field such as the developing machines, the printing field such as printing machines, and the painting field such as painting equipment, the material can be used as rolls, belts, seals, valve parts, etc. in dry copying machines.

[0107] Specific uses in the above-mentioned fields of photography, printing and coating include surface layers of transfer rolls in copiers, cleaning blades in copiers, and belts in copiers; rolls (for example, fixing rolls, pressure rolls, and the like) and belts for office automation equipment such as copiers, printers and facsimiles; rolls, roll blades and belts in PPC copiers; rolls in film developing machines and X-ray film developing machines; printing rolls, scrapers, tubes, valve parts and belts in printing machines; ink tubes, rolls and belts in printers; coating rolls, scrapers, tubes and valve parts in coating and painting equipment; developing rolls, gravure rolls, guide rolls, guide rolls in magnetic tape production coating lines, gravure rolls and coating rolls in magnetic tape production coating lines, etc.

[0108] In the food equipment field, including the food plant equipment and household goods, the present invention can be used in food manufacturing processes, food transporters, or food storage devices.

[0109] Specific uses in the food equipment field include seals for plate-type heat exchangers, solenoid valve seals for vending machines, packing for thermos pots, sanitary pipe packing, packing for pressure cookers, water heater seals, heat exchanger gaskets, diaphragms and packing for food processing equipment, rubber materials for food processing equipment (for example, heat exchanger gaskets, diaphragms, various seals such as O-rings, piping, hoses, sanitary packing, valve packing, and filling packing used as a joint between the mouth of a bottle or the like and the filler during filling), etc. Further examples include packings, gaskets, tubes, diaphragms, hoses, and joint sleeves used in products such as alcoholic beverages and soft drinks, filling equipment, food sterilization equipment, brewing equipment, water heaters, various automatic food vending machines, etc.

[0110] In the field of nuclear power plant equipment, the material can be used for check valves and pressure reducing valves around nuclear reactors, and seals for uranium hexafluoride enrichment equipment.

[0111] Specific uses in the above general industrial fields include sealing materials for hydraulic equipment such as machine tools, construction machinery, and hydraulic machinery; seals and bearing seals for hydraulic and lubricating machinery; sealing materials used for mandrels, 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 presses, transport belts (conveyor belts), squeeze rolls for pickling steel plates, etc., robot cables, solvent squeeze rolls for aluminum rolling lines, etc., coupler O-rings, acid-resistant cushioning materials, dust seals and lip rubbers for sliding parts of cutting machinery, gaskets for food waste incinerators, friction materials, surface modifiers for metals or rubber, and coating materials. It can also be used as gaskets and sealing materials for equipment used in papermaking processes, sealants for clean room filter units, construction sealants, protective coatings for concrete and cement, glass cloth impregnation materials, polyolefin processing aids, polyethylene moldability improving additives, fuel containers for small generators and lawn mowers, pre-coated metals obtained by applying a primer treatment to metal plates, etc. In addition, it can also be used as sheets and belts by impregnating woven fabric and baking it.

[0112] Specific examples of use in the steel industry include iron plate processing rolls in iron plate processing equipment.

[0113] Specific applications in the electrical field include insulating oil caps for bullet trains, venting seals for liquid-sealed transformers, transformer seals, oil well cable jackets, seals for electric furnaces and other ovens, window frame seals for microwave ovens, sealants used to bond the wedges and necks of CRTs, sealants for halogen lamps, fixing agents for electrical components, sealants for the termination of sheathed heaters, and sealants used for insulating and moisture-proofing lead terminals for electrical equipment. It can also be used as a coating for oil-resistant and heat-resistant electric wires, highly heat-resistant electric wires, chemical-resistant electric wires, highly insulating electric wires, high-voltage power transmission lines, cables, electric wires used in geothermal power generation equipment, and electric wires used around automobile engines. It can also be used as an oil seal or shaft seal for vehicle cables. Furthermore, it can be used as an electrical insulating material (for example, insulating spacers for various electrical devices, insulating tape for cable joints and ends, and heat-shrinkable tubing), and as a material for electrical and electronic devices used in high-temperature environments (for example, motor lead wire materials and electrical wire materials for high-temperature furnaces).It can also be used as an encapsulating layer or protective film (back sheet) for solar cells.

[0114] In the field of fuel cells, the material can be used as a sealing material between electrodes and between electrodes and separators in polymer electrolyte fuel cells, phosphate fuel cells, etc., as well as seals, packings, and separators for piping for hydrogen, oxygen, generated water, etc.

[0115] 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), and the like. It is also used as a shock absorber (crash stopper) for hard disk drives, a binder for electrode active materials in nickel-metal hydride 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, coatings, 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 resins such as epoxy, a shatterproof material for light bulbs, a gasket for computers, a cooling hose for large computers, packing such as gaskets and O-rings for secondary batteries, particularly lithium secondary batteries, a sealing layer covering one or both outer surfaces of an organic EL structure, a connector, a damper, and the like.

[0116] In the field of chemical transport equipment, it can be used as a safety valve or shipping valve for trucks, trailers, tank trucks, ships, etc.

[0117] In the field of parts for mining equipment for exploring for and extracting energy resources such as oil and gas, they are used as various sealing materials used in the mining of oil, natural gas, etc., and as boots for electrical connectors used in oil wells.

[0118] Specific uses in the above-mentioned energy resource exploration and mining equipment parts field include drill bit seals, pressure adjustment diaphragms, seals for horizontal drilling motors (stators), stator bearing (shaft) seals, sealing materials used in blowout preventers (BOP), sealing materials used in rotary blowout preventers (pipe wipers), sealing materials and gas-liquid connectors used in MWD (real-time drilling information detection systems), logging tool seals (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 include seals used in drilling equipment, seals, packings and motor linings used in mud pumps, underground audiometer covers, U-cups, composition seating cups, rotary seals, laminated elastomeric bearings, flow control seals, sand control seals, safety valve seals, seals for hydraulic fracturing equipment, seals and packings for linear packers and linear hangers, wellhead seals and packings, seals and packings for chokes and valves, sealing materials for LWD (logging while drilling), diaphragms used in oil exploration and drilling applications (for example, diaphragms for supplying lubricating oil to oil drilling pits), gate valves, electronic boots, and sealing elements for drilling guns.

[0119] It can also be used for joint seals in kitchens, bathrooms, washrooms, etc.; cover cloths for outdoor tents; seals for printing materials; rubber hoses for gas heat pumps, fluorocarbon-resistant rubber hoses; agricultural films, linings, and weather-resistant covers; and tanks made of laminated steel sheets used in the construction and home appliance fields.

[0120] Furthermore, it can also be used as an article bonded to a metal such as aluminum, etc. Examples of such uses include door seals, gate valves, pendulum valves, solenoid tips, as well as metal-rubber parts bonded to metals such as piston seals, diaphragms, and metal gaskets.

[0121] It can also be used for rubber parts, brake shoes, brake pads, etc. in bicycles.

[0122] The molded article can also be applied to belts.

[0123] Examples of belts include the following: power transmission belts (including flat belts, V-belts, V-ribbed belts, toothed belts, etc.); conveyor belts (conveyor belts) such as flat belts used in various high-temperature locations around the engines of agricultural machinery, machine tools, industrial machinery, etc.; conveyor belts for transporting loose or granular materials such as coal, crushed stone, soil and sand, ore, and wood chips in high-temperature environments; conveyor belts used in steel mills 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; and toothed belts used in automobiles, office automation equipment, medical applications, printing machines, etc.

[0124] In particular, timing belts are typical toothed belts for automobiles.

[0125] The belt may have a single layer structure or a multi-layer structure.

[0126] 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 made of other material.

[0127] In the multi-layer belt, the layers made of other materials include layers made of other rubbers, layers made of thermoplastic resins, various fiber reinforcement layers, canvas, and metal foil layers.

[0128] The molded products can also be used for industrial vibration-damping pads, vibration-damping mats, railway slab mats, pads, automotive vibration-damping rubber, etc. Automotive vibration-damping rubber includes vibration-damping rubber for engine mounts, motor mounts, member mounts, strut mounts, bushings, dampers, muffler hangers, center bearings, etc.

[0129] Other applications include joint members such as flexible joints and expansion joints, boots, grommets, etc. In the marine field, for example, marine pumps can be mentioned.

[0130] Joint components are fittings used in piping and piping equipment, and are used for purposes such as preventing vibrations and noise generated by piping systems, absorbing expansion and contraction and displacement caused by temperature and pressure changes, absorbing dimensional fluctuations, and mitigating and preventing the effects of earthquakes and land subsidence.

[0131] Flexible joints and expansion joints can be preferably used as complex shaped molded articles for, for example, shipbuilding piping, mechanical piping such as pumps and compressors, chemical plant piping, electrical piping, civil engineering and water supply piping, and automobiles. The boots can be preferably used as complex shaped molded articles such as 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.

[0132] The molded articles can also be used as diaphragms for filter presses, blowers, water supply diaphragms, liquid storage tanks, pressure switches, accumulators, and air springs for suspensions, etc.

[0133] By adding the molded article to rubber or resin, an anti-slip agent can be obtained that provides molded articles or coating films that are non-slip in wet environments such as rain, snow, ice, and sweat.

[0134] 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.

[0135] The molded articles can also contribute to the impermeability of various substrates, such as sealing gaskets for weapons applications and protective clothing against contact with aggressive chemical agents.

[0136] It can also be used in O-rings, V-rings, X-rings, packings, gaskets, diaphragms, oil seals, bearing seals, lip seals, plunger seals, door seals, lip and face seals, gas delivery plate seals, wafer support seals, barrel seals, and other sealing materials used to seal lubricating oils (engine oil, transmission oil, gear oil, etc.) containing amine additives (especially amine additives used as antioxidants and detergents / dispersants) and greases (especially urea-based greases) used in transportation such as automobiles and ships, and can also be used in tubes, hoses, various rubber rolls, coatings, belts, valve bodies, etc. It can also be used as a laminating material and lining material.

[0137] It can also be used as a coating material for heat- and oil-resistant 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. to detect oil temperature and / or oil pressure, and in high-temperature oil environments such as in automatic transmissions and engine oil pans.

[0138] In addition, vulcanized coatings may be formed on molded products for use in applications such as non-stick, oil-resistant rolls for copying machines, weather-resistant and anti-icing weather strips, rubber stoppers for infusions, rubber vial stoppers, mold release agents, non-stick lightweight conveyor belts, anti-stick coatings for car engine mount gaskets, coatings for synthetic fibers, and bolt members or joints with thin packing coating layers.

[0139] The use of molded products for automobile-related parts also includes use in motorcycle parts with similar structures.

[0140] Furthermore, examples of the fuels used in the automobile industry include light oil, gasoline, and fuels for diesel engines (including biodiesel fuels).

[0141] The molded article can also be used as a sealing member for a rolling bearing.

[0142] Examples of the rolling bearing include a ball bearing, a roller bearing, a bearing unit, and a linear bearing.

[0143] Examples of the ball bearing include a radial ball bearing, a thrust ball bearing, and a thrust angular ball bearing.

[0144] 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.

[0145] The deep groove ball bearing is used in, for example, electric motors, household electrical appliances, office automation equipment, and the like.

[0146] Examples of angular contact ball bearings include single-row angular contact ball bearings, duplex angular contact ball bearings, and double-row angular contact ball bearings. Single-row angular contact ball bearings are used in electric motors, household electrical appliances, office equipment, and hydraulic pumps and vertical pumps that are subject to axial loads in addition to radial loads. Duplex angular contact ball bearings are used in machine tool main spindles 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.

[0147] The four-point contact ball bearings described above are used in reducers and other devices where axial loads are applied from both directions and large bearing widths are not available.

[0148] The self-aligning ball bearing is used in places where it is difficult to align the shaft with the housing, or for transmission shafts where the shaft is prone to deflection.

[0149] The thrust ball bearings include single-direction thrust ball bearings and double-direction thrust ball bearings, and are applicable to the conventionally known uses for these ball bearings.

[0150] The above-mentioned thrust angular contact ball bearing is used in combination with a double-row cylindrical roller bearing to support the axial load of the main shaft of a machine tool.

[0151] Examples of the roller bearing include a radial roller bearing and a thrust roller bearing.

[0152] Examples of the radial roller bearing include cylindrical roller bearings, needle roller bearings, tapered roller bearings, and self-aligning roller bearings.

[0153] The cylindrical roller bearings are used in general machinery, machine tools, electric motors, reducers, railway axles, aircraft, etc.

[0154] Needle roller bearings are used in general machinery, automobiles, electric motors, etc.

[0155] Tapered roller bearings are used in machine tools, automotive and railway axles, rolling mills, reducers, etc.

[0156] Spherical roller bearings are used in general machinery, rolling mills, paper-making machines, axles, etc.

[0157] Examples of the thrust roller bearing include a thrust cylindrical roller bearing, a thrust needle roller bearing, a thrust tapered roller bearing, and a thrust spherical roller bearing.

[0158] Thrust cylindrical roller bearings are used in machine tools, general machinery, etc.

[0159] Thrust needle roller bearings are used in automobiles, pumps, general machinery, etc.

[0160] Thrust tapered roller bearings are used in general machinery, rolling mills, etc.

[0161] Spherical thrust roller bearings are used in cranes, extruders, general machinery, etc.

[0162] The fluororubber cross-linking composition can be used not only as a molded product after cross-linking but also as various parts in various industrial fields. Next, the uses of the fluororubber cross-linking composition will be described.

[0163] 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-stickiness, such as metal gaskets and oil seals; non-stick 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.

[0164] By making the fluororubber cross-linking composition high viscosity and high concentration, it can be used as a sealing material, lining or sealant for complex shapes in the usual way, by making it low viscosity it can be used to form thin films of several microns, and by making it medium viscosity it can be used to apply pre-coated metal, O-rings, diaphragms and reed valves.

[0165] Furthermore, it can also be used to coat transport rolls or belts for woven fabrics or paper sheets, printing belts, chemical-resistant tubes, chemical stoppers, fuel hoses, etc.

[0166] Examples of substrates that can be coated with the fluororubber cross-linking composition include metals such as iron, stainless steel, copper, aluminum, and brass; glass products such as glass plates and glass fiber woven and nonwoven fabrics; molded articles and coated products made of general-purpose and heat-resistant resins such as polypropylene, polyoxymethylene, polyimide, polyamideimide, polysulfone, polyethersulfone, and polyetheretherketone; molded articles and coated products made of general-purpose rubbers such as SBR, butyl rubber, NBR, and EPDM, and heat-resistant rubbers such as silicone rubber and fluororubber; and woven and nonwoven fabrics made of natural and synthetic fibers.

[0167] Coatings formed from the fluororubber cross-linking composition can be used in fields where heat resistance, solvent resistance, lubricity, and non-stickiness are required, 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, and engine gaskets.

[0168] The fluororubber crosslinking composition can also be dissolved in a solvent and used as a paint or adhesive, or as an emulsified dispersion (latex) and used as a paint.

[0169] 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 or organic substrates such as metals, ceramics, glass, stone, concrete, plastics, rubber, wood, paper, and fiber.

[0170] The fluororubber cross-linking composition can be applied to a substrate or the like by dispenser coating or screen printing coating.

[0171] The fluororubber crosslinking composition may be used as a coating composition for casting a film or for dipping a substrate such as fabric, plastic, metal, or elastomer.

[0172] In particular, the fluororubber crosslinking composition, in the form of a latex, may be used to produce coated fabrics, protective gloves, impregnated fibers, O-ring coatings, coatings for fuel system quick connect O-rings, coatings for fuel system seals, coatings for fuel tank rollover valve diaphragms, coatings for fuel tank pressure sensor diaphragms, coatings for oil filters and fuel filter seals, coatings for fuel tank sender seals and sender head fitting seals, coatings for copier fuser rolls, and polymer coating compositions.

[0173] They are useful for coating silicone rubber, nitrile rubber, and other elastomers. They are also useful for coating parts made from such elastomers to enhance both the permeation resistance and chemical resistance of the substrate elastomer as well as its thermal stability. Other applications include coatings for heat exchangers, expansion joints, vats, tanks, fans, flue ducts and other ductwork, and containment structures, such as concrete containment structures. Fluoroelastomer crosslinking compositions may also be applied to exposed cross sections of multilayer component structures, for example, in hose construction and diaphragm manufacturing processes. Sealing members in connections and joints often consist of hard materials, and fluoroelastomer crosslinking compositions provide improved frictional interfaces, enhanced dimensional interference fits with reduced leakage along the sealing surfaces. The latex enhances seal durability in various automotive system applications.

[0174] They can also be used in the manufacture of power steering systems, fuel systems, air conditioning systems, and any joints where hoses and tubes are connected to another component. Another useful application of fluoroelastomer crosslinking compositions is in repairing manufacturing defects (and damage caused by use) in multi-layer rubber structures, such as three-layer fuel hoses. Fluoroelastomer crosslinking compositions are also useful for coating thin steel sheets, which can be formed or embossed before or after paint is applied. For example, multiple layers of coated steel can be assembled to create a gasket between two rigid metal components. A sealing effect is achieved by applying a fluoroelastomer crosslinking composition between the layers. This process can be used to manufacture engine head gaskets and exhaust manifold gaskets, reducing bolt forces and strain on the assembled components while providing better fuel economy and lower emissions due to lower cracking, deflection, and hole distortion.

[0175] 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 a metal or ceramic; or a multi-layer product formed by coating on a substrate containing an inorganic material such as a metal or ceramic.

[0176] The fluororubber cross-linking composition is also suitable as a wiring material for lightweight, flexible electronic devices and can be used in known electronic components. Examples of such electronic components include CMOS electronic circuits, transistors, integrated circuits, organic transistors, light-emitting elements, actuators, memories, sensors, coils, capacitors, and resistors. By using this composition, flexible electronic devices such as solar cells, various displays, sensors, actuators, electronic artificial skin, sheet-type scanners, Braille displays, and wireless power transmission sheets can be obtained.

[0177] Although the embodiments have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the claims. [Example]

[0178] Next, embodiments of the present disclosure will be described with reference to examples, but the present disclosure is not limited to these examples.

[0179] The values ​​in the examples were measured by the following methods.

[0180] <Fluororubber Monomer Composition> 19 Measurement was performed using F-NMR (Bruker AC300P model).

[0181] <Fluorine content> 19 The composition was calculated from the fluoroelastomer composition measured by F-NMR.

[0182] <Mooney viscosity> Measurements were made in accordance with ASTM D1646-15 and JIS K6300-1:2013 at a temperature of 121°C.

[0183] <Glass transition temperature (Tg)> A DSC curve was obtained by heating 10 mg of sample at 20°C / min using a differential scanning calorimeter (DSC822e, manufactured by Mettler-Toledo, or X-DSC7000, manufactured by 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.

[0184] <Heat of fusion> A differential scanning calorimeter (DSC822e, manufactured by Mettler-Toledo, or X-DSC7000, manufactured by Hitachi High-Tech Science) was used to obtain a DSC curve by heating 10 mg of sample at a rate of 20°C / min, and the heat of fusion was calculated from the magnitude of the melting peak (ΔH) that appeared in the DSC curve.

[0185] <Acid value> Measurement was carried out in accordance with the potentiometric titration method of JIS K0070, except that a 0.01 mol / L potassium hydroxide ethanol solution was used instead of a 0.1 mol / L potassium hydroxide ethanol solution.

[0186] <Crosslinking characteristics (maximum torque (MH), optimum crosslinking time (T90))> For the fluororubber crosslinking composition, during the primary crosslinking, using a vulcanization tester (MDR H2030 manufactured by M & C Co., Ltd.), the crosslinking curve was obtained at the temperature shown in Table 1, and from the change in torque, the maximum torque (MH) and the optimum crosslinking time (T90) were determined.

[0187] <M100, tensile strength and elongation at break> Using a crosslinked sheet with a thickness of 2 mm, a test piece in the shape of dumbbell No. 6 was prepared. Using the obtained test piece and a tensile tester (Tensilon RTG - 1310 manufactured by A&D Co., Ltd.), in accordance with JIS K6251:2010, under the condition of 500 mm / min, the 100% modulus (M100), tensile strength and elongation at break at 23°C were measured.

[0188] <Hardness> Three crosslinked sheets with a thickness of 2 mm were stacked, and in accordance with JIS K625 3 -3:2012, the durometer hardness (type A, peak value, value after 3 seconds) was measured.

[0189] <Heat aging test> Using a crosslinked sheet with a thickness of 2 mm, a test piece in the shape of dumbbell No. 6 was prepared. After the obtained test piece was heat - treated at 275°C for 72 hours, using the above - mentioned method, the tensile strength of the heat - treated test piece was measured. And for the tensile strength, the change rate of the measured values before and after the heat treatment was calculated according to the following formula. ΔX=(X - X0) / X0×100 ΔX: Change rate (%) X0: Measured value before heat treatment X: Measured value after heat treatment

[0190] <Compression set> Using a small test piece for measuring compression set, measurements were taken in accordance with Method A of JIS K6262:2013, at a compression ratio of 25%, a test temperature of 200°C, and a test time of 72 hours.

[0191] 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 the second run Acid value: 0.15KOHmg / g Fluorine rubber B: Vinylidene fluoride / hexafluoropropylene molar ratio: 78 / 22 Fluorine content: 66% Mooney viscosity (ML1+10 (121℃)): 98 Glass transition temperature: -18℃ Heat of fusion: Not observed in the second run Acid value: 0.56KOHmg / g

[0192] MT Carbon (N2SA:8m 2 / g, DBP: 43ml / 100g) Calcium hydroxide Magnesium oxide Crosslinking accelerator: a mixture of 91% by mass of benzyldimethyloctadecylammonium chloride and 9% by mass of isopropyl alcohol

[0193] Crosslinker-A: 9,9-bis(4-hydroxyphenyl)fluorene Crosslinker-B: Hydroquinone Crosslinker-C: 2-methylresorcinol Crosslinker-D: Bisphenol A Crosslinker-E: 4,4'-dihydroxydiphenyl ether Crosslinker-F: Bis(4-hydroxyphenyl) sulfone Crosslinker-G: 4,4'-dihydroxybenzophenone

[0194] Examples 1 to 2 and Comparative Examples 1 to 6 The components were blended according to the recipe in Table 1 and kneaded on an open roll to prepare a fluororubber cross-linking composition. The maximum torque (MH) and optimal cross-linking time (T90) of the obtained fluororubber cross-linking composition are shown in Table 1. The fluororubber cross-linking composition was then cross-linked by primary cross-linking (press cross-linking) under the conditions shown in Table 1 and secondary cross-linking (oven cross-linking) at 230°C for 24 hours to obtain a cross-linked sheet (2 mm thick) and a small test piece for measuring compression set. The evaluation results of the obtained cross-linked sheet and the results of the compression set test are shown in Table 1.

[0195] [Table 1]

[0196] From the results shown in Table 1, it can be seen that although the same fluororubber was used in Example 1 and Comparative Examples 1 to 6, Example 1, which used the compound represented by general formula (b) as the crosslinking agent, produced molded articles with smaller compression set, greater tensile strength, and a smaller rate of change in tensile strength after heat aging tests than Comparative Examples 1 to 6, which used conventional crosslinking agents. Therefore, it is clear that by using the fluororubber crosslinking composition of the present disclosure, molded articles with excellent high-temperature compression set properties, tensile strength, and heat resistance can be obtained.

Claims

1. A composition for crosslinking fluororubber, comprising a polyol-crosslinkable fluororubber (a) and a crosslinking agent (b), wherein the crosslinking agent (b) is at least one selected from the group consisting of a compound represented by the following general formula (b) and a salt of said compound with an alkali metal, an alkaline earth metal or an onium compound: 【Chemistry 5】 (In the formula, m and n independently represent integers of 1 to 3.)

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

3. 3. The composition for crosslinking fluororubber according to claim 1, wherein the content of the crosslinking agent (b) is 0.5 to 50 mmol per 100 parts by mass of the fluororubber (a).

4. The fluororubber cross-linking composition according to any one of claims 1 to 3, further comprising a cross-linking accelerator (c).

5. The fluororubber crosslinking composition according to any one of claims 1 to 4, further comprising an acid acceptor (d).

6. The fluororubber crosslinking composition according to any one of claims 1 to 5, further comprising 0.1 to 50 parts by mass of an acid acceptor (d) per 100 parts by mass of the fluororubber (a).

7. The fluororubber cross-linking composition according to any one of claims 1 to 6, further comprising at least one acid acceptor (d) selected from the group consisting of metal oxides, metal hydroxides, alkali metal silicates, metal salts of weak acids, and hydrotalcites.

8. The fluororubber cross-linking composition according to any one of claims 1 to 7, wherein the cross-linking agent (b) is at least one selected from the group consisting of a compound represented by the following formula (b1) and a salt of said compound with an alkali metal, an alkaline earth metal or an onium compound: 【Chemistry 6】

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

10. A sealing material obtained from the fluororubber crosslinking composition according to any one of claims 1 to 8.

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