Fluororubber crosslinking composition and molded article

Abstract

To provide a fluororubber crosslinking composition that enables crosslinking at a high crosslinking rate and also yields a molded product with a high crosslinking density.SOLUTION: A fluororubber crosslinking composition includes a fluororubber (a), an additive (b), a dehydrofluorination agent (c), a crosslinker (d), an organic peroxide (e), and a co-crosslinker (f), where the additive (b) is at least one selected from the group consisting of silver compounds and copper compounds, and the crosslinker (d) is at least one selected from the group consisting of compounds with one or more hydroxy groups (d1), onium salts of compounds (d1), alkali metal salts of compounds (d1), alkaline-earth metal salts of compounds (d1), and esters derived from compounds (d1) and carboxylic acids.SELECTED DRAWING: None

Description

Technical Field

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

Background Art

[0002] In Patent Document 1, (A)(i) A vinylidene fluoride unit, (ii) a hexafluoropropylene unit, and optionally (iii) a tetrafluoroethylene unit of 35% by weight or less, and the weight ratio of the (i) unit to the (ii) unit is 40:60 to 80:20, and the intrinsic viscosity is 40 to 200 ml / g, and the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn), Mw / Mn, is in the range of 3 to 25, containing bound iodine, and having a multi-peak molecular weight distribution, a fluorine-containing elastomer, and (B)(iv) A polyhydroxy aromatic compound, (v) at least one selected from ammonium salts, phosphonium salts, and iminium salts, and (vi) at least one selected from divalent metal oxides and divalent metal hydroxides, a polyol vulcanization compounding agent, or (vii) a polyamine compound and (viii) a divalent metal oxide, a polyamine vulcanization compounding agent, or both (C) An organic peroxide and (D) A polyfunctional unsaturated compound A fluorine-containing elastomer composition containing the above is described.

[0003] In Patent Document 2, (a) A fluororubber containing iodine or bromine, (b) An organic peroxide, (c) A polyfunctional compound, and (d) A silver compound A composition for vulcanizing fluororubber characterized by containing the above is described.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

[0005] The object of this disclosure is to provide a fluororubber crosslinking composition that can be crosslinked at a high crosslinking rate and can produce molded products with a high crosslinking density. [Means for solving the problem]

[0006] The present disclosure provides a fluororubber crosslinking composition comprising a fluororubber (a), an additive (b), a hydrofluoricating agent (c), a crosslinking agent (d), an organic peroxide (e), and a cocrosslinking agent (f), wherein the additive (b) is at least one selected from the group consisting of silver compounds and copper compounds, and the crosslinking agent (d) is at least one selected from the group consisting of a compound (d1) having at least one hydroxyl group, an onium salt of compound (d1), an alkali metal salt of compound (d1), an alkaline earth metal salt of compound (d1), and an ester derived from compound (d1) and a carboxylic acid. [Effects of the Invention]

[0007] According to this disclosure, it is possible to provide a fluororubber crosslinking composition that can be crosslinked at a high crosslinking rate and can produce molded articles with a high crosslinking density. [Modes for carrying out the invention]

[0008] The following describes specific embodiments of this disclosure in detail, but this disclosure is not limited to the embodiments described below.

[0009] The fluororubber crosslinking composition of this disclosure contains fluororubber (a), an additive (b), a hydrofluoricating agent (c), a crosslinking agent (d), an organic peroxide (e), and a cocrosslinking agent (f).

[0010] Conventionally, as a fluororubber crosslinking composition, as described in Patent Document 1, a composition is known which is obtained by blending a polyol vulcanization compound or a polyamine vulcanization compound, an organic peroxide, and a polyfunctional unsaturated compound with a fluorine-containing elastomer having a specific configuration. According to Patent Document 1, by using such a composition, a vulcanized product with high strength and excellent balance between strength and elongation can be obtained, and furthermore, the compression set is improved because the crosslinking density is increased.

[0011] However, there is a need for a fluororubber crosslinking composition that can produce molded fluororubber products with higher productivity than conventional methods, and furthermore, can produce molded products with an even higher crosslinking density than conventional molded products.

[0012] It has been found that by blending a hydrofluoric acid removal agent, a crosslinking agent, an organic peroxide, and a co-crosslinking agent with fluororubber, and by blending at least one additive selected from the group consisting of silver compounds and copper compounds, a fluororubber crosslinking composition can be obtained that can crosslink at a higher crosslinking rate than conventional fluororubber crosslinking compositions, and moreover, can provide molded articles with a higher crosslinking density than molded articles obtained from conventional fluororubber crosslinking compositions.

[0013] The components of the fluororubber crosslinking composition of this disclosure will be described below.

[0014] (a) Fluororubber The fluororubber crosslinking compositions of this disclosure contain fluororubber. In this disclosure, fluororubber is an amorphous fluoropolymer. "Amorphous" means that the magnitude of the melting peak (ΔH) observed in differential scanning calorimetry (DSC) (heating rate 10°C / min) or differential thermal analysis (DTA) (heating rate 10°C / min) of the fluoropolymer is 4.5 J / g or less. By crosslinking, fluororubber exhibits elastomer properties. Elastomer properties mean 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.

[0015] The fluororubber may be a partially fluorinated rubber or a perfluororubber, but it is preferably a partially fluorinated rubber. Partially fluorinated rubber is a fluoropolymer that contains fluoromonomer units, has a perfluoromonomer unit content of less than 90 mol% relative to the total polymerization units, has a glass transition temperature of 20°C or lower, and has a melting peak (ΔH) of 4.5 J / g or lower.

[0016] A perfluoromonomer is a monomer that does not contain carbon-hydrogen atom bonds in its molecule. The above perfluoromonomer may contain carbon atoms and fluorine atoms, or it may contain some fluorine atoms bonded to carbon atoms that are replaced by chlorine atoms, or it may contain nitrogen atoms, oxygen atoms, sulfur atoms, phosphorus atoms, boron atoms, or silicon atoms in addition to carbon atoms. Preferably, the above perfluoromonomer is one in which all hydrogen atoms are replaced by fluorine atoms. The above perfluoromonomer does not contain monomers that provide crosslinking sites.

[0017] A monomer that provides crosslinking sites is a monomer (curation site monomer) that has crosslinkable groups that provide crosslinking sites to a fluoropolymer for crosslinking by a crosslinking agent.

[0018] The fluororubber used in this disclosure is not particularly limited and includes fluororubber known as peroxide crosslinkable fluororubber and fluororubber known as polyol crosslinkable fluororubber. Alternatively, it may be a fluororubber that can be crosslinked using a pyridinium-type salt as described in Japanese Patent Publication No. 2018-514627.

[0019] Peroxide-crosslinkable fluororubber is fluororubber having peroxide-crosslinkable moieties. The peroxide-crosslinkable moieties are not particularly limited and include, for example, iodine atoms, bromine atoms, and CN groups present in the fluororubber; and carbon-carbon unsaturated bonds present in the main chain or side chain of the fluororubber. In this disclosure, peroxide-crosslinkable fluororubber may be used as the fluororubber, but this does not mean that the crosslinking reaction of the fluororubber crosslinking composition of this disclosure proceeds in the same way as the crosslinking reaction of conventionally known peroxide-crosslinkable fluororubber.

[0020] A polyol-crosslinkable fluororubber is a fluororubber having polyol-crosslinkable moieties. A polyol-crosslinkable partially fluorinated rubber is preferred as the polyol-crosslinkable fluororubber. The polyol-crosslinkable fluororubber is not particularly limited, but vinylidene fluoride (VdF)-based fluororubbers are examples. While a polyol-crosslinkable fluororubber may be used as the fluororubber in this disclosure, this does not mean that the crosslinking reaction of the fluororubber crosslinking composition of this disclosure proceeds in the same manner as the crosslinking reaction of conventionally known polyol-crosslinkable fluororubbers.

[0021] Examples of fluororubbers having polyol-crosslinkable moieties include VdF-based fluororubbers and rubbers having polyol-crosslinkable functional moieties in the side chains and / or main chain. Examples of fluororubbers having polyol-crosslinkable moieties include non-perfluorofluororubbers and fluororubbers containing -CH2- (methylene group) in the main chain. Examples of fluororubbers having polyol-crosslinkable moieties include, A vinylidene fluoride (VDF)-based fluoroelastomer substantially lacking polar end groups, as described in Japanese Patent Publication No. 2003-277563. A vinylidene fluoride-based fluoroelastomer comprising repeating units derived from vinylidene fluoride (VDF) as described in Japanese Patent Publication No. 2018-527449 and repeating units derived from at least one additional (per)fluorinated monomer, A cured fluoroelastomer of 100 parts (phr) containing less than 67% by weight of a small amount of fluorine as described in Japanese Patent Application Laid-Open No. 7-316377, 40 to 68% by weight of vinylidene fluoride (VDF) units, and 20 to 50% by weight of hexafluoropropylene (HFP) units, and optionally containing one or more comonomers having unsaturated ethylene etc. may be used.

[0022] As the fluororubber used in the present disclosure, a fluororubber (VdF-based fluororubber) containing vinylidene fluoride (VdF) units is preferred.

[0023] Examples of VdF-based fluororubbers include tetrafluoroethylene (TFE) / propylene / VdF-based fluororubbers, ethylene / hexafluoropropylene (HFP) / VdF-based fluororubbers, VdF / HFP-based fluororubbers, VdF / TFE / HFP-based fluororubbers, and the like. These fluororubbers having polyol crosslinkable sites can be used alone or in any combination within a range not impairing the effects of the present disclosure.

[0024] As the VdF-based fluororubber, those represented by the following general formula (1) are preferred.

[0025] -(M 1 )-(M 2 )-(N 1 )- (1) (In the formula, the structural unit M 1 is a structural unit derived from vinylidene fluoride (m 1 ), the structural unit M 2 is a structural unit derived from a fluorinated ethylenic monomer (m 2 ), and the structural unit N 1 is a repeating unit derived from monomer (m 1 ) and monomer (m 2 ) copolymerizable with monomer (n 1 ))

[0026] Among the VdF-based fluororubbers represented by the general formula (1), the structural unit M 1is 30 to 85 mol%, structural unit M 2 is preferably contained in an amount of 55 to 15 mol%, more preferably structural unit M 1 is 50 to 80 mol%, structural unit M 2 is 50 to 20 mol%. Structural unit N 1 is the structural unit M 1 and the structural unit M 2 is preferably 0 to 20 mol% based on the total amount of

[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) (wherein, 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 of 0 to 6 (provided that 0 < q + r ≦ 6 is satisfied)), the fluorine-containing monomer represented by general formula (3): CHX 11 = CX 12 Rf 4 (3) (wherein, X 11 and X 12 are such that one is H and the other is F, and Rf 4 is a linear or branched fluoroalkyl group having 1 to 12 carbon atoms)), and fluorine-containing monomers such as vinyl fluoride can be mentioned. Among these, TFE, HFP, and PAVE are preferred.

[0028] Monomer (n1 ) as monomer (m 1 ) and monomers (m 2 Any material that can copolymerize with ) is acceptable, but examples include ethylene, propylene, alkyl vinyl ethers, monomers that provide crosslinking sites, and bisolefin compounds. These can be used individually or in any combination.

[0029] Examples of monomers that provide such cross-linking sites include those with the general formula (4): CY 1 2 = CY 1 -Rf 5 CHR 1 X 41 (4) (In the formula, Y 1 These are independently a hydrogen atom, a fluorine atom or -CH3, Rf 5 is a fluoroalkylene group, a perfluoroalkylene group, a fluoropolyoxyalkylene group, or a perfluoropolyoxyalkylene group, R 1 is a hydrogen atom or -CH3, X 41 (Iodine atom or bromine atom) is an iodine or bromine-containing monomer, general formula (5): CF2 = CFO(CF2CF(CF3)O) m (CF2) n -X 51 (5) (In the formula, m is an integer from 0 to 5, n is an integer from 1 to 3, X 51 A monomer represented by a cyano group, a carboxyl group, an alkoxycarbonyl group, a bromine atom, or an iodine atom, general formula (6): CH2=CH(CF2) p I (6) Examples include monomers represented by formulas (where p is an integer from 1 to 10), such as iodine-containing monomers like perfluoro(6,6-dihydro-6-iodo-3-oxa-1-hexene) and perfluoro(5-iodo-3-oxa-1-pentene) as described in Japanese Patent Publication No. 5-63482 and Japanese Patent Application Publication No. 7-316234, and iodine-containing monomers like CF2=CFOCF2CF2CH2I as described in Japanese Patent Application Publication No. 4-217936. Examples include iodine-containing monomers, such as 4-iodo-3,3,4,4-tetrafluoro-1-butene described in Japanese Patent Publication No. 61-55138, bromine-containing monomers described in Japanese Patent Publication No. 4-505341, cyano group-containing monomers, carboxyl group-containing monomers, and alkoxycarbonyl group-containing monomers described in Japanese Patent Publication Nos. 4-505345 and 5-500070. These can be used individually or in any combination. Furthermore, as the bisolefin compound, those described in Japanese Patent Publication No. 8-12726 can be used.

[0030] Specifically, preferred examples of the above-mentioned 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] As rubber having polyol-crosslinkable functional sites in the side chains and / or main chain, see Japanese Patent Publication No. 60-44511 or Japanese Patent No. 3890630 for tetrafluoroethylene (TFE) / perfluoro(alkyl vinyl ether) (PAVE) / R 1 CH=CR 2 R 3 (R in the formula 1 and R 2 R is independently selected from hydrogen and fluorine, and R 3 Examples include rubbers composed of copolymer units consisting of curing site monomers (independently selected from hydrogen, fluorine, alkyl, and perfluoroalkyl), and rubbers having double bonds in the side chains and / or main chain.

[0032] Among these, the fluororubber is preferably a fluororubber composed of VdF and at least one other fluorine-containing monomer, and is 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 is more preferably at least one rubber selected from the group consisting of VdF / HFP-based fluororubber and VdF / TFE / HFP-based fluororubber.

[0033] The fluororubber preferably has a Mooney viscosity (ML1+10(100°C)) of 2 or higher at 100°C, more preferably 10 or higher, even more preferably 20 or higher, and particularly preferably 30 or higher. It is also preferably 200 or lower, more preferably 150 or lower, even more preferably 120 or lower, and particularly preferably 100 or lower. The Mooney viscosity is measured in accordance with ASTM D1646-15 and JIS K6300-1:2013.

[0034] Fluororubber preferably has a fluorine content of 50 to 75% by mass. More preferably, it is 60 to 73% by mass, and even more preferably, 63 to 72% by mass. The fluorine content is calculated from the composition ratio of the monomer units constituting the fluororubber.

[0035] Fluororubber is preferably a glass transition temperature of -50 to 0°C. The glass transition temperature can be determined by using a differential scanning calorimeter to obtain a DSC curve by heating 10 mg of the sample at 20°C / min, and then finding the temperature at which the extension of the baseline before and after the second-order transition of the DSC curve intersects with the tangent line at the inflection point of the DSC curve.

[0036] Fluororubber may contain at least one of iodine atoms and bromine atoms, or may contain only iodine atoms. The total content of iodine and bromine atoms in fluororubber is preferably 0.001 to 10% by mass, more preferably 5.0% by mass or less, even more preferably 1.0% by mass or less, particularly preferably 0.7% by mass or less, most preferably 0.5% by mass or less, more preferably 0.01% by mass or more, even more preferably 0.05% by mass or more, particularly preferably 0.08% by mass or more, and most preferably 0.10% by mass or more. The bonding positions of iodine and bromine atoms in fluororubber may be at the ends of the main chain or the ends of the side chains, or of course, both.

[0037] The iodine content can be measured by the following method: Mix Na2CO3 and K2CO3 in a 1:1 (weight ratio), and dissolve the resulting mixture in 20 ml of pure water to prepare an absorption solution. Mix 12 mg of the sample (fluorine polymer) with 5 mg of Na2SO3 to prepare a mixture, burn it in oxygen in a quartz flask, and introduce the resulting combustion gas into the absorption solution. After letting the resulting absorption solution stand for 30 minutes, measure the concentration of iodide ions in the absorption solution using a Shimadzu 20A ion chromatograph. The iodide ion content can then be determined from the measured values ​​using calibration curves created with KI standard solutions containing 0.5 ppm and 1.0 ppm of iodide ions.

[0038] Fluororubber having at least one of iodine atoms and bromine atoms can be produced, for example, by polymerizing iodine or bromine-containing monomers, or by polymerizing using a bromine compound or iodine compound as a polymerization initiator or chain transfer agent.

[0039] A polymerization method using bromine or iodine compounds as chain transfer agents includes, for example, emulsion polymerization in an aqueous medium under pressurized conditions in the presence of a bromine or iodine compound, in a substantially oxygen-free environment (iodine transfer polymerization). Typical examples of bromine or iodine compounds used include, for example, General formula: R 8 I x Br y (In the formula, x and y are integers from 0 to 2, and satisfy 1 ≤ x + y ≤ 2, R 8 Examples of compounds are those represented by a saturated or unsaturated fluorohydrocarbon group or chlorofluorohydrocarbon group having 1 to 16 carbon atoms, or a hydrocarbon group having 1 to 3 carbon atoms (which may contain an oxygen atom).

[0040] Examples of bromine and iodine compounds include 1,3-diiodoperfluoropropane, 2-iodoperfluoropropane, 1,3-diiodo-2-chloroperfluoropropane, 1,4-diiodoperfluorobutane, 1,5-diiodo-2,4-dichloroperfluoropentane, 1,6-diiodoperfluorohexane, 1,8-diiodoperfluorooctane, 1,12-diiodoperfluorododecane, 1,16-diiodoperfluorohexadecane, diiodomethane, 1,2-diiodoethane, 1,3-diiodo-n-propane, CF2Br2, BrCF2CF2Br, CF3CFBrCF2Br, CFClBr2, and BrCF2. Examples include CFClBr, CFBrClCFClBr, BrCF2CF2CF2Br, BrCF2CFBrOCF3, 1-bromo-2-iodoperfluoroethane, 1-bromo-3-iodoperfluoropropane, 1-bromo-4-iodoperfluorobutane, 2-bromo-3-iodoperfluorobutane, 3-bromo-4-iodoperfluorobutene-1, 2-bromo-4-iodoperfluorobutene-1, monoiodomonobromo substituted derivatives of benzene, diiodomonobromo substituted derivatives, and (2-iodoethyl) and (2-bromoethyl) substituted derivatives. These compounds may be used individually or in combination with each other.

[0041] Among these, 1,4-diiodoperfluorobutane, 1,6-diiodoperfluorohexane, and 2-iodoperfluoropropane are preferred in terms of polymerization reactivity, crosslinking reactivity, and availability.

[0042] The fluororubber described above can be manufactured by conventional methods.

[0043] (b) Additives The fluororubber crosslinking composition of this disclosure contains at least one additive selected from the group consisting of compounds and copper compounds. In addition to a hydrofluoricating agent, a crosslinking agent, an organic peroxide, and a co-crosslinking agent, the fluororubber crosslinking composition of this disclosure further contains at least one additive selected from the group consisting of silver compounds and copper compounds, thereby enabling crosslinking at a high crosslinking rate and producing molded articles with high crosslink density.

[0044] The silver compound may be either an inorganic silver compound or an organosilver compound, but an inorganic silver compound is preferred. Examples of silver compounds include silver oxide, silver halide, silver sulfide, silver cyanide, silver nitrate, silver sulfate, and silver acetate, with silver oxide being the most preferred.

[0045] The copper compound may be either an inorganic copper compound or an organocopper compound, but an inorganic copper compound is preferred. Examples of copper compounds include copper oxide, copper halide, copper sulfide, copper cyanide, copper nitrate, copper sulfate, and copper acetate, with copper oxide being the most preferred.

[0046] In one embodiment of the fluororubber crosslinking composition, a silver compound is included as an additive. In another embodiment of the fluororubber crosslinking composition, at least one selected from the group consisting of silver(I) oxide and silver(II) oxide is included as an additive.

[0047] In one embodiment of the fluororubber crosslinking composition, a copper compound is included as an additive. In another embodiment of the fluororubber crosslinking composition, at least one selected from the group consisting of copper(I) oxide and copper(II) oxide is included as an additive.

[0048] The additive content is preferably 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, even more preferably 0.1 to 3 parts by mass, and particularly preferably 0.1 to 1.5 parts by mass, per 100 parts by mass of fluororubber, as this allows for crosslinking at an even higher crosslinking rate and enables the production of molded products with an even higher crosslinking density.

[0049] (c) Hydrofluoricating agent The fluororubber crosslinking composition of this disclosure contains a hydrofluoric acid removal agent. The use of a hydrofluoric acid removal agent can promote the crosslinking reaction by promoting the formation of intramolecular double bonds in the hydrofluoric acid removal reaction of the fluororubber main chain.

[0050] Examples of dehydrofluoridating agents include onium compounds. The onium compounds are not particularly limited and include ammonium salts such as quaternary ammonium salts, phosphonium salts such as quaternary phosphonium salts, and sulfonium salts, among which quaternary ammonium salts and quaternary phosphonium salts are preferred.

[0051] The quaternary ammonium salt is not particularly limited, and for example, 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 hydrooxide, 8-methyl-1,8-diazabicyclo[5,4,0]-7-undecenium methyl sulfide 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 hydrooxide, 8-eicosyl-1,8-diazabicyclo[5,4,0]-7 Examples include undecénium chloride, 8-tetracosyl-1,8-diazabicyclo[5,4,0]-7-undecénium chloride, 8-benzyl-1,8-diazabicyclo[5,4,0]-7-undecénium chloride (hereinafter referred to as DBU-B), 8-benzyl-1,8-diazabicyclo[5,4,0]-7-undecénium hydrooxide, 8-phenethyl-1,8-diazabicyclo[5,4,0]-7-undecénium chloride, 8-(3-phenylpropyl)-1,8-diazabicyclo[5,4,0]-7-undecénium chloride, benzyldimethyloctadecylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium chloride, benzyltributylammonium chloride, benzyltriethylammonium chloride, tetrabutylammonium bisulfate, and tetrabutylammonium hydroxide. Among these, DBU-B or benzyldimethyloctadecylammonium chloride are preferred in terms of crosslinking properties and the physical properties of the crosslinked product.

[0052] Furthermore, the quaternary phosphonium salt is not particularly limited, and examples 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 in terms of crosslinkability and the physical properties of the crosslinked product.

[0053] The content of the dehydrofluoride agent is preferably 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, even more preferably 0.1 to 3 parts by mass, and particularly preferably 0.1 to 1.5 parts by mass, per 100 parts by mass of fluororubber, in order to obtain molded products with even better performance due to the crosslinking reaction being at an appropriate rate and the compression set characteristics at high temperatures. When the crosslinking agent is an onium salt of compound (d1), the content of the dehydrofluoride agent includes the mass of the cationic portion of the crosslinking agent (i.e., cations derived from the onium compound).

[0054] (d) Crosslinking agent The fluororubber crosslinking composition of this disclosure contains a crosslinking agent.

[0055] The crosslinking agent contained in the fluororubber crosslinking composition disclosed herein is A compound having at least one hydroxyl group (d1), Onium salt of compound (d1), Alkali metal salt of compound (d1), Alkaline earth metal salts of compound (d1), and, Esters derived from compound (d1) and carboxylic acid It is at least one selected from the group consisting of the following:

[0056] The number of hydroxyl groups in compound (d1) is at least 1, preferably 2 or more, preferably 4 or less, more preferably 3 or less, and even more preferably 2 or less. In one embodiment, compound (d1) has 2 hydroxyl groups directly bonded to carbon atoms constituting an aromatic ring within its molecule. The hydroxyl groups in compound (d1) may form esters with carboxylic acids, as will be described later. That is, compound (d1) may have alkylcarbonyloxy groups instead of hydroxyl groups. In one embodiment, compound (d1) has 2 hydroxyl groups, or 1 hydroxyl group and 1 alkylcarbonyloxy group.

[0057] As compound (d1), compounds conventionally known as crosslinking agents for polyol crosslinking (crosslinking agents for polyol crosslinking) can be suitably used.

[0058] Examples of such compounds include polyhydroxy compounds such as polyhydroxyaromatic compounds. Polyhydroxyaromatic compounds are not particularly limited and include, for example, 2,2-bis(4-hydroxyphenyl)propane (hereinafter referred to as bisphenol A), 2,2-bis(4-hydroxyphenyl)perfluoropropane (hereinafter referred to as bisphenol AF), resorcinol, 1,3-dihydroxybenzene, 1,7-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 4,4'-dihydroxydiphenyl, 4,4'-dihydroxystilbene, 2,6- Examples include dihydroxyanthracene, hydroquinone, catechol, 2,2-bis(4-hydroxyphenyl)butane (hereinafter referred to as bisphenol B), 4,4-bis(4-hydroxyphenyl)valeric acid, 2,2-bis(4-hydroxyphenyl)tetrafluorodichloropropane, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl ketone, tri(4-hydroxyphenyl)methane, 3,3',5,5'-tetrachlorobisphenol A, and 3,3',5,5'-tetrabromobisphenol A.

[0059] Furthermore, as compound (d1), a compound (d1-1) can also be suitably used, which has an aromatic ring, two or more hydroxyl groups directly bonded to the carbon atoms constituting the aromatic ring, and at least one of the Hammett substituent constants σm and σp is 0.03 or greater, and has 1 to 6 substituents (γ) directly bonded to the carbon atoms constituting the aromatic ring (excluding substituents containing hydroxyl groups and alkylcarbonyloxy groups).

[0060] The aromatic ring may be monocyclic or polycyclic. The aromatic ring may be a so-called heterocyclic ring composed not only of carbon atoms, but also of carbon atoms and heteroatoms such as oxygen, sulfur, and nitrogen atoms. In the aromatic ring, the carbon atoms of the carbonyl group may constitute the ring structure.

[0061] Examples of monocyclic aromatic rings include monocyclic 5- to 7-membered aromatic rings, specifically benzene rings and monocyclic 5- to 7-membered aromatic heterocyclic rings (including 7-membered rings with a tropone structure) are preferred, benzene rings, furan rings, and thiophene rings are more preferred, and benzene rings are even more preferred.

[0062] The number of aromatic rings in the polycyclic aromatic ring is 2 or more, preferably 2 to 8, more preferably 2 to 4, even more preferably 2 or 3, and particularly preferably 2.

[0063] The polycyclic aromatic ring is preferably a polycyclic aromatic hydrocarbon ring or a polycyclic aromatic heterocycle, and more preferably a polycyclic aromatic hydrocarbon ring. The polycyclic aromatic hydrocarbon ring may be a polycyclic, fused, or spiro ring in which two rings are linked by a bond.

[0064] The number of carbon atoms in the polycyclic aromatic hydrocarbon ring is preferably 3 to 30, more preferably 5 or more, even more preferably 6 or more, more preferably 20 or less, and even more preferably 14 or less.

[0065] The number of rings in the polycyclic aromatic hydrocarbon ring is preferably 2 to 4, more preferably 2 or 3, and even more preferably 2.

[0066] As for polycyclic aromatic hydrocarbon rings, Polycyclic aromatic hydrocarbon rings, such as biphenyl rings, diphenylmethane rings, diphenyl ether rings, diphenyl sulfone rings, and diphenyl ketone rings, are formed by the linkage of two rings via a bond. Condensed polycyclic hydrocarbon rings such as naphthalene rings, phenanthrene rings, anthracene rings, fluorene rings, tetracene rings, chrysene rings, pyrene rings, pentacene rings, benzopyrene rings, triphenylene rings, and azulene rings; These are some examples.

[0067] Among the polycyclic aromatic hydrocarbon rings, naphthalene rings or biphenyl rings are particularly preferred.

[0068] In polycyclic aromatic heterocycles, the carbonyl group may constitute part of the aromatic ring. Polycyclic aromatic heterocycles also include rings composed only of carbon atoms and the oxygen atoms of the carbonyl group.

[0069] As the polycyclic aromatic heterocycle, a ring formed by a carbon atom and atoms other than carbon atoms is preferred. The atoms other than carbon atoms are preferably nitrogen atoms, oxygen atoms, or sulfur atoms, with oxygen atoms or sulfur atoms being more preferred. That is, as the heterocycle, nitrogen-containing heterocycles, oxygen-containing heterocycles, or sulfur-containing heterocycles are preferred, with oxygen-containing heterocycles or sulfur-containing heterocycles being more preferred. The number of atoms other than carbon atoms in the ring is preferably 1 to 3.

[0070] The number of rings in the polycyclic aromatic heterocycle is preferably 2 to 4, more preferably 2 or 3, and even more preferably 2.

[0071] As the polycyclic aromatic heterocycle, oxygen-containing polycyclic aromatic heterocycles are preferred, such as xanthene rings, 1-benzopyran rings, 2-benzopyran rings, 1-benzofuran rings, and 2-benzofuran rings.

[0072] As aromatic rings, a benzene ring, a naphthalene ring, or a biphenyl ring is preferred, and a benzene ring is more preferred, because it allows for the acquisition of molded articles with even higher crosslinking density and even better compression set characteristics at high temperatures.

[0073] Compound (d1-1) has an aromatic ring, along with a hydroxyl group and a substituent (γ).

[0074] The number of hydroxyl groups in compound (d1-1) is 2 or more, preferably 4 or less, and more preferably 3 or less. In one embodiment, compound (d1-1) has 2 hydroxyl groups directly bonded to carbon atoms constituting an aromatic ring within its molecule. The hydroxyl groups in compound (d1-1) may form esters with carboxylic acids, as will be described later. That is, compound (d1-1) may have alkylcarbonyloxy groups instead of hydroxyl groups.

[0075] The substituent (γ) does not include substituents containing a hydroxyl group or alkylcarbonyloxy groups. Substituents containing a hydroxyl group include hydroxyl groups and groups that have a hydroxyl group as part of their structure.

[0076] The total number of substituents (γ) in compound (d1-1) is preferably 1 to 4, more preferably 1 or 2, and even more preferably 1.

[0077] The substituent (γ) is a monovalent substituent in which at least one of Hammett's substituent constants σm and σp is 0.03 or greater. The substituent constant σm and σp of substituent (γ) is preferably 0.05 or greater, more preferably 0.10 or greater, preferably 1.40 or less, more preferably 1.00 or less, and even more preferably 0.80 or less.

[0078] In one embodiment, the value of the substituent constant σm of substituent (γ) is 0.03 or greater, preferably 0.05 or greater, more preferably 0.10 or greater, preferably 1.40 or less, more preferably 1.00 or less, and even more preferably 0.80 or less.

[0079] In one embodiment, the substituent constant σp of substituent (γ) is 0.03 or greater, preferably 0.05 or greater, more preferably 0.10 or greater, preferably 1.40 or less, more preferably 1.00 or less, and even more preferably 0.80 or less.

[0080] Hammett's rule is an empirical rule proposed by L.P. Hammett in 1935 to quantitatively discuss the effects of substituents on the reactions or equilibrium of benzene derivatives, and it is widely accepted today. The substituent constants derived from Hammett's rule include σp and σm values, which can be found in many general textbooks. In this invention, however, we will adopt the values ​​described in "TABLE 1 Hammett and Modified Swain-Lupton Constants" in Chem. Rev., 1991, Vol. 91, pp. 165-195. For substituents not described in the above document, we will adopt values ​​calculated according to the calculation method described in the document "The Effect of Structure upon the Reactions of Organic Compounds. Benzene Derivatives" (J. Am. Chem. Soc. 1937, 59, 1, 96-103).

[0081] Compound (d1-1) includes compounds that are not benzene derivatives, but the σm and σp values ​​are used as measures of the electronic effects of substituents, regardless of the substitution position. In this disclosure, the σm and σp values ​​are used in this sense.

[0082] Specifically, the substituents (γ) include: partially fluorinated C1-C5 alkyl groups, C1-C5 perfluoroalkyl groups, fluorine atoms, chlorine atoms, C1-C5 alkoxycarbonyl groups (excluding the carbon atoms constituting the carbonyl group), partially fluorinated C1-C5 alkoxycarbonyl groups (excluding the carbon atoms constituting the carbonyl group), C1-C5 perfluoroalkoxycarbonyl groups, C1-C5 alkoxy groups, partially fluorinated C1-C5 alkoxy groups, C1-C5 perfluoroalkyloxy groups, and C1-C5 atoms (excluding the carbon atoms constituting the carbonyl group). Examples include acyloxy groups in which 1 to 5 carbon atoms (excluding the number of carbon atoms) are partially fluorinated, perfluoroacyloxy groups with 1 to 5 carbon atoms (excluding the number of carbon atoms constituting the carbonyl group), acyl groups with 0 to 5 carbon atoms (excluding the number of carbon atoms constituting the carbonyl group), acyl groups with 0 to 5 carbon atoms (excluding the number of carbon atoms constituting the carbonyl group) are partially fluorinated, perfluoroacyl groups with 0 to 5 carbon atoms (excluding the number of carbon atoms constituting the carbonyl group), alkylsulfonyl groups with 1 to 5 carbon atoms, alkylsulfonyl groups with 1 to 5 carbon atoms (excluding the number of carbon atoms constituting the carbonyl group), perfluoroalkylsulfonyl groups with 1 to 5 carbon atoms, and trimethoxysilyl groups.

[0083] The substituent (γ) is preferably at least one selected from the group consisting of a C1-C5 partially fluorinated alkyl group, a C1-C5 perfluoroalkyl group, a fluorine atom, a chlorine atom, a C1-C5 alkoxy group, a C0-C5 alkoxycarbonyl group (excluding the number of carbon atoms constituting the carbonyl group), and a C0-C5 acyl group (excluding the number of carbon atoms constituting the carbonyl group), and also includes a C1-C5 perfluoroalkyl group, a fluorine atom, a chlorine atom, a C1-C5 alkoxy group, a C0-C5 alkoxycarbonyl group (excluding the number of carbon atoms constituting the carbonyl group), and It is more preferable that the group consists of acyl groups having 0 to 5 carbon atoms (excluding the number of carbon atoms constituting the carbonyl group), it is even more preferable that the group consists of perfluoroalkyl groups having 1 to 5 carbon atoms, fluorine atoms, chlorine atoms, and acyl groups having 0 to 5 carbon atoms (excluding the number of carbon atoms constituting the carbonyl group), it is even more preferable that the group consists of chlorine atoms, fluorine atoms, acetyl groups, methoxycarbonyl groups, and methoxy groups, and it is particularly preferable that the group consists of acetyl groups and methoxycarbonyl groups.

[0084] As compound (d1-1), a compound represented by general formula (d1-1-1) or a compound represented by general formula (d1-1-2) is preferred.

[0085] General formula (d1-1-1): [ka] (In the formula, m is 1 or 2, X is a substituent (γ), and n is an integer from 1 to 3.)

[0086] General formula (d1-1-2): [ka] (In the formula, a and b are independently 1 or 2, X 1 and X 2Each of the following is an independent substituent (γ), c and d are independent integers from 0 to 3 (where the sum of c and d is an integer of 1 or more), and A is a single bond, an alkylene group having 1 to 13 carbon atoms, an arylene group having 6 to 13 carbon atoms, a thiocarbonyl group, an oxy group, a carbonyl group, a sulfinyl group, or a sulfonyl group, and these groups may contain one or both of a chlorine atom and / or a fluorine atom.

[0087] In the general formula (d1-1-1), m represents the number of hydroxyl groups bonded to the benzene ring. m is 1 or 2, preferably 1. X represents a substituent (γ) bonded to the benzene ring. n represents the number of substituents (γ) bonded to the benzene ring. n is an integer from 1 to 3, preferably 1 or 2, more preferably 1.

[0088] In the general formula (d1-1-2), a and b represent the number of hydroxyl groups bonded to the two benzene rings, respectively. a and b are independently 1 or 2, and preferably 1.

[0089] In the general formula (d1-1-2), A represents the type of bond connecting the two benzene rings, and can be a single bond, an alkylene group having 1 to 13 carbon atoms, an arylene group having 6 to 13 carbon atoms, a thiocarbonyl group, an oxy group, a carbonyl group, a sulfinyl group, or a sulfonyl group. If these groups have a substituted hydrogen atom, the hydrogen atom may be substituted with a chlorine atom and a fluorine atom. That is, these groups may contain one or both of a chlorine atom and a fluorine atom. A is preferably a single bond or an alkylene group having 1 to 13 carbon atoms, and more preferably a single bond.

[0090] In general formula (d1-1-2), X 1 and X 2represents the substituent (γ) attached to each of the two benzene rings. c and d represent the number of substituents (γ) attached to each of the two benzene rings. c and d are independently integers from 0 to 3, provided that the sum of c and d is an integer of 1 or more. If the sum of c and d is 2 or more, it is preferable that each of the two benzene rings has at least one substituent (γ) attached. c and d are independently preferably integers from 1 to 3, more preferably 1 or 2, and even more preferably 1.

[0091] The crosslinking agent may be an onium salt of compound (d1), an alkali metal salt of compound (d1), an alkaline earth metal salt of compound (d1), or an ester derived from compound (d1) and a carboxylic acid. Among these salts and esters, the onium salt of compound (d1) is preferred. The onium salt of compound (d1) is an onium salt composed of an anionic moiety derived from compound (d1) and a cationic moiety derived from an onium compound. By using an onium salt as the crosslinking agent (d), the onium salt not only acts as a crosslinking agent but also as a hydrofluoricating agent.

[0092] The onium salt of compound (d1) is obtained by reacting compound (d1) with an alkaline substance such as sodium hydroxide in water or an organic solvent, or with metallic sodium in an organic solvent, followed by a reaction with an onium compound such as benzyltriphenylphosphonium chloride, and then distilling off the water or organic solvent. Alternatively, the reaction product solution may be filtered or the reaction product washed with water or an organic solvent as needed to remove by-products such as sodium chloride.

[0093] As the alkali metal, Na or K is preferred. As the alkaline earth metal, Ca or Mg is preferred.

[0094] Examples of onium salts include ammonium salts, phosphonium salts, and sulfonium salts.

[0095] Examples of onium compounds that make up onium salts include ammonium compounds, phosphonium compounds, and sulfonium compounds.

[0096] The onium compounds constituting the onium salt are preferably ammonium compounds and phosphonium compounds, more preferably phosphonium compounds, even more preferably quaternary phosphonium compounds, and among these, benzyltriphenylphosphonium is particularly preferred. The ammonium compounds are preferably quaternary ammonium compounds, and more preferably 8-benzyl-1,8-diazabicyclo[5,4,0]-7-undecenium and benzyldimethyloctadecylammonium.

[0097] Esters derived from compound (d1) and a carboxylic acid are obtained, for example, by reacting compound (d1) with the carboxylic acid. The ester has alkylcarbonyloxy groups in place of some or all of the hydroxyl groups of compound (d1).

[0098] Examples of alkylcarbonyloxy groups include those with the general formula: RC(=O)-O- A group represented by (wherein R is an alkyl group having 1 to 5 carbon atoms) is preferred. The number of carbon atoms in the alkyl group is preferably 1 to 3, and more preferably 1. R is preferably a methyl group.

[0099] The crosslinking agent content is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 6 parts by mass, even more preferably 0.7 to 5 parts by mass, and particularly preferably 0.7 to 2.5 parts by mass, in order to ensure that the crosslinking reaction in the crosslinking process proceeds at an appropriate rate and that a molded article with sufficient tensile strength, elongation at break, compression set characteristics at high temperatures, and appropriate hardness can be obtained. When the crosslinking agent is an onium salt of compound (d1), the above crosslinking agent content (parts by mass) is the value after deducting the mass of the cationic portion of the crosslinking agent (i.e., cations derived from the onium compound).

[0100] (e) Organic peroxides The fluororubber crosslinking composition of this disclosure contains an organic peroxide.

[0101] As organic peroxides, those that readily generate peroxy radicals in the presence of heat or an oxidation-reduction system are preferred. Specifically, examples include 1,1-bis(t-butylperoxy)-3,5,5-trimethylcyclohexane, 2,5-dimethylhexane-2,5-dihydroperoxide, di-t-butylperoxide, t-butylcumylperoxide, dicumylperoxide, α,α'-bis(t-butylperoxy)-p-diisopropylbenzene, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, 2,5-dimethyl-2,5-bis(t-butylperoxy)-hexyne-3, benzoylperoxide, t-butylperoxybenzene, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, t-butylperoxymaleic acid, t-butylperoxyisopropyl carbonate, and t-butylperoxybenzoate. Among these, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane and 2,5-dimethyl-2,5-bis(t-butylperoxy)-hexyne-3 are preferred.

[0102] The amount of organic peroxide is preferably 0.05 to 10 parts by mass, more preferably 0.1 parts by mass or more, more preferably 5 parts by mass or less, and even more preferably 1 part by mass or less, per 100 parts by mass of fluororubber, as this allows for crosslinking at an even higher crosslinking rate and enables the production of molded products with an even higher crosslinking density.

[0103] (f) Cocrosslinking agent The fluororubber crosslinking composition of this disclosure contains a co-crosslinking agent. Suitable co-crosslinking agents include those known as crosslinking agents for peroxide crosslinking (co-crosslinking agents for peroxide crosslinking).

[0104] Co-crosslinking agents include triallyl cyanurate, trimetallyl isocyanurate, triallyl isocyanurate (TAIC), triacrylic formal, triallyl trimellitate, N,N'-m-phenylene bismaleimide, dipropagyl terephthalate, diallyl phthalate, tetraallyl terephthalate amide, triallyl phosphate, bismaleimide, and fluorinated triallyl isocyanurate (1,3,5-tris(2,3,3-trifluoro-2-propenyl)-1,3,5-triadyl Examples include N-2,4,6-trione, tris(diallylamine)-S-triazine, triallyl phosphite, N,N-diallylcrylamide, 1,6-divindodecafluorohexane, hexaarylphosphoramide, N,N,N',N'-tetraallylphthalamide, N,N,N',N'-tetraallylmalonamide, trivinyl isocyanurate, 2,4,6-trivinylmethyltrisiloxane, tri(5-norbornene-2-methylene)cyanurate, and triallyl phosphite. Among these, triallyl isocyanurate (TAIC) is preferred. When mixing the fluororubber with the co-crosslinking agent, the co-crosslinking agent may be impregnated with an inert inorganic powder or the like.

[0105] The co-crosslinking agent content is preferably 0.1 to 10 parts by mass, and more preferably 0.5 to 5 parts by mass, per 100 parts by mass of fluororubber, as this allows for crosslinking at a higher rate and results in a molded product with a higher crosslink density.

[0106] (g) Acid suction agent The fluororubber crosslinking composition of this disclosure may further contain an acid acceptor. By including an acid acceptor, the crosslinking reaction of the fluororubber crosslinking composition proceeds more smoothly, and the compression set characteristics at high temperatures are further improved.

[0107] Examples of acid acceptors include metal oxides such as magnesium oxide, calcium oxide, bismuth oxide, and zinc oxide; metal hydroxides such as calcium hydroxide; alkali metal silicates described in Japanese Patent Publication No. 2011-522921, such as hydrotalcite and sodium metasilicate; and metal salts of weak acids described in Japanese Patent Publication No. 2003-277563. Examples of metal salts of weak acids include carbonates, benzoates, oxalates, and phosphates of Ca, Sr, Ba, Na, and K.

[0108] As an 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 it allows for the acquisition of molded articles with even better compression set characteristics at high temperatures. Sodium metasilicate hydrate, calcium hydroxide, magnesium oxide, bismuth oxide, and hydrotalcite are more preferred. Furthermore, if the resulting molded article requires good water resistance, acid resistance, or resistance to organic acid esters including biodiesel, at least one selected from the group consisting of bismuth oxide and hydrotalcite is preferred as the acid acceptor.

[0109] In the fluororubber crosslinking composition, the acid acceptor content is preferably 0.1 to 100 parts by mass, more preferably 1 to 50 parts by mass, even more preferably 1 to 30 parts by mass, and particularly preferably 1 to 20 parts by mass, per 100 parts by mass of fluororubber, in order to obtain molded products with even better compression set characteristics at high temperatures.

[0110] When the acid acceptor content increases, the water resistance, acid resistance, and resistance to organic acid esters, including biodiesel, of the resulting molded product tend to decrease. On the other hand, when the acid acceptor content decreases, the crosslinking rate decreases, and the mechanical properties tend to deteriorate due to the decrease in crosslinking density. Therefore, the acid acceptor content can be selected according to the application of the resulting molded product. Furthermore, when an acid acceptor other than calcium hydroxide is included, by reducing the calcium hydroxide content to 0 to 1.5 parts by mass, and then adjusting the crosslinking density by adjusting the content of the other acid acceptor, it is possible to obtain a molded product with even better compression set characteristics at high temperatures.

[0111] (h) Other components The fluororubber crosslinking composition may contain, as needed, various additives commonly used in fluororubber crosslinking compositions, such as fillers (carbon black, bituminous coal, barium sulfate, diatomaceous earth, calcined clay, talc, wollastonite, carbon nanotubes, etc.), processing aids (wax, etc.), plasticizers, colorants, stabilizers, tackifiers (coumarone resin, coumarone-indene resin, etc.), release agents, conductivity modifiers, thermal conductivity modifiers, surface non-tackeners, flexibility modifiers, heat resistance improvers, flame retardants, foaming agents, antioxidants described in International Publication No. 2012 / 023485, and may also contain one or more commonly used crosslinking agents and dehydrofluoridating agents different from those mentioned above.

[0112] Of these, thermal carbon black and furnace carbon black are preferred as carbon blacks, and MT carbon black, FT carbon black, and SRF carbon black are more preferred. When carbon black with a relatively large particle size, such as carbon black or FT carbon black, is blended, molded products with excellent compression set characteristics can be obtained, while when carbon black with a fine particle size is blended, molded products with excellent strength and elongation can be obtained. By blending different grades in combination, the above characteristics can be balanced.

[0113] As fillers other than carbon black, barium sulfate and wollastonite are preferred.

[0114] The processing aids are not particularly limited, but may include, for example, aliphatic amines such as stearylamine, fatty acid esters such as stearic acid esters and sebacate esters, fatty acid amides such as stearic acid amide, long-chain alkyl alcohols, natural waxes, polyethylene waxes, phosphate esters such as tricresyl phosphate, and silicone-based processing aids. If necessary, blending two or more of these in appropriate amounts may improve the balance between mold release properties during molding and the physical properties of the molded product.

[0115] The content of fillers 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 per 100 parts by mass of fluororubber.

[0116] The content of processing aids such as wax is preferably 0 to 10 parts by mass, more preferably 0 to 5 parts by mass, and particularly preferably 0 to 2 parts by mass, per 100 parts by mass of fluororubber. Since the use of processing aids, plasticizers, and mold release agents tends to reduce the mechanical properties and sealing properties of the resulting molded product, it is necessary to adjust their content within an acceptable range for the desired properties of the resulting molded product.

[0117] The fluororubber crosslinking composition may contain a dialkylsulfone compound. The inclusion of a dialkylsulfone compound enhances the crosslinking efficiency, speed, compression set characteristics, and fluidity of the rubber material. Examples of dialkylsulfone compounds include dimethyl sulfone, diethyl sulfone, dibutyl sulfone, methyl ethyl sulfone, diphenyl sulfone, and sulfolane. Among these, sulfolane is preferred from the viewpoint of crosslinking efficiency, compression set characteristics, and its suitable boiling point. The content of the dialkylsulfone compound is preferably 0 to 10 parts by mass, more preferably 0 to 5 parts by mass, and particularly preferably 0 to 3 parts by mass, per 100 parts by mass of fluororubber. When the fluororubber crosslinking composition of this disclosure contains a dialkylsulfone compound, the lower limit of the dialkylsulfone compound content may be, for example, 0.1 parts by mass or more per 100 parts by mass of fluororubber.

[0118] Since this provides a good balance of crosslinking rate, fluidity of the rubber material during molding, mold release properties during molding, and mechanical properties of the molded product, the above-mentioned dialkyl sulfone compound and the above-mentioned processing aid may be combined.

[0119] A fluororubber crosslinking composition is obtained by mixing fluororubber (a), additives (b), a hydrofluoricating agent (c), a crosslinking agent (d), an organic peroxide (e), a cocrosslinking agent (f), etc., using a commonly used rubber mixing apparatus. Suitable rubber mixing apparatuses include rolls, kneaders, Banbury mixers, internal mixers, and twin-screw extruders.

[0120] Furthermore, in order to uniformly disperse each component in the rubber, a method may be used in which some components are melted and mixed at a high temperature of 100 to 200°C using a closed-type mixing device such as a kneader, and then the remaining components are mixed at a relatively lower temperature.

[0121] Furthermore, by mixing fluororubber (a), additives (b), hydrofluoricating agent (c), crosslinking agent (d), organic peroxide (e), co-crosslinking agent (f), etc., and then leaving it at room temperature for 12 hours or more before mixing it again, the dispersibility can be further improved.

[0122] <Molded products> A molded article of the present disclosure can be obtained by crosslinking a fluororubber crosslinking composition. Alternatively, a molded article of the present disclosure can be obtained by molding and crosslinking a fluororubber crosslinking composition. The fluororubber crosslinking composition can be molded by conventionally known methods. The molding and crosslinking methods and conditions may be within the range of known methods and conditions for the molding and crosslinking adopted. The order of molding and crosslinking is not limited; molding may be performed first and then crosslinking, or crosslinking may be performed first and then molding, or molding and crosslinking may be performed simultaneously.

[0123] Examples of molding methods include compression molding, injection molding, injection molding, extrusion molding, and molding by funnel curing, but are not limited to these. Crosslinking methods include steam crosslinking, heating crosslinking, and radiation crosslinking, with steam crosslinking and heating crosslinking being preferred. Specific crosslinking conditions, which are not limited to these, can generally be determined appropriately depending on the type of crosslinking agent (b), hydrofluoricating agent (c), organic peroxide (d), and acid acceptor (e), within a temperature range of 140-250°C and a crosslinking time of 1 minute to 24 hours.

[0124] Furthermore, heating the resulting molded product in an oven or the like can improve its mechanical properties such as tensile strength, heat resistance, and compression set characteristics at high temperatures. Specific crosslinking conditions, though not limited to these, can typically be determined appropriately depending on the type of crosslinking agent (b), hydrofluoricating agent (c), organic peroxide (d), and acid acceptor (e), within a temperature range of 140 to 300°C and a duration of 30 minutes to 72 hours.

[0125] The molded articles of this disclosure exhibit excellent properties such as heat resistance, oil resistance, chemical resistance, and flexibility, and furthermore, they have excellent compression set characteristics at high temperatures. Therefore, the molded articles of this disclosure can be used in general for parts that come into contact with other materials and slide, for sealing or enclosing other materials or substances, or for vibration damping and sound damping purposes, and can be used as various components in various fields such as the automotive industry, aerospace industry, and semiconductor industry.

[0126] Fields in which it is used include, for example, semiconductor-related fields, automotive fields, aircraft fields, space and rocket fields, shipbuilding fields, chemical fields such as chemical plants, pharmaceutical fields such as pharmaceuticals, photographic fields such as developing machines, printing fields such as printing machines, painting fields such as painting equipment, analytical and physicochemical machinery fields such as analytical instruments and measuring instruments, food machinery fields including food plant equipment and household goods, beverage and food manufacturing equipment fields, pharmaceutical manufacturing equipment fields, medical parts fields, chemical transport equipment fields, nuclear power plant equipment fields, steel fields such as sheet metal processing equipment, general industrial fields, electrical fields, fuel cell fields, electronic components fields, optical instrument components fields, space equipment components fields, petrochemical plant equipment fields, oil and gas exploration and extraction equipment components fields, petroleum refining fields, and petroleum transport equipment components fields.

[0127] Examples of applications for molded products 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, and barrel seals. As sealing materials, they can be used in applications where heat resistance, solvent resistance, chemical resistance, and non-stick properties are required.

[0128] It can also be used as a tube, hose, roll, various rubber rolls, flexible joint, rubber sheet, coating, belt, damper, valve, valve seat, valve body, chemical-resistant coating material, laminating material, lining material, and more.

[0129] The cross-sectional shapes of the rings, packings, and seals mentioned above may vary. Specifically, they may be square, O-shaped, ferrule, or other shapes such as D-shaped, L-shaped, T-shaped, V-shaped, X-shaped, or Y-shaped.

[0130] In the semiconductor-related fields mentioned above, for example, it can be used in semiconductor manufacturing equipment, liquid crystal panel manufacturing equipment, plasma panel manufacturing equipment, plasma display panel manufacturing equipment, plasma address liquid crystal panel manufacturing equipment, organic EL panel manufacturing equipment, field emission display panel manufacturing equipment, solar cell substrate manufacturing equipment, semiconductor transport equipment, etc. Such equipment includes, for example, CVD equipment, gas control devices such as gas control devices for semiconductors, 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 deposition 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. Examples include 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 using hydrofluoric acid, hydrochloric acid, sulfuric acid, ozonated water, etc., steppers, coaters / developers, CMP equipment, excimer laser exposure machines, chemical piping, gas piping, equipment for plasma treatment such as NF3 plasma treatment, O2 plasma treatment, and fluorine plasma treatment, heat treatment film deposition equipment, wafer transport equipment, wafer cleaning equipment, silicon wafer cleaning equipment, silicon wafer processing equipment, equipment used in the LP-CVD process, equipment used in the lamp annealing process, and equipment used in the reflow process.

[0131] Specific applications in the semiconductor-related field include, for example, various sealing materials such as O-rings and gaskets for gate valves, quartz windows, chambers, chamber lids, gates, bell jars, couplings, and pumps; various sealing materials such as O-rings for resist developers and strippers, as well as hoses and tubes; linings and coatings for resist developer tanks, stripper tanks, wafer cleaning tanks, and wet etching tanks; pump diaphragms; rolls for wafer transport; hoses and tubes for wafer cleaning solutions; sealing materials for cleanrooms and other clean equipment such as sealants; sealing materials for storage facilities that store semiconductor manufacturing equipment and devices such as wafers; and diaphragms for chemical transfer used in the semiconductor manufacturing process.

[0132] In the automotive sector mentioned above, it can be used in the engine itself, main motion system, valve train, lubrication and cooling system, fuel system, intake and exhaust system, drivetrain transmission system, chassis steering system, brake system, and electrical components such as basic electrical components, control system electrical components, and equipment electrical components. Note that the automotive sector also includes motorcycles.

[0133] In the engine body and its peripheral equipment as described above, molded products can be used for various sealing materials that require heat resistance, oil resistance, fuel oil resistance, antifreeze resistance for engine cooling, and steam resistance. Examples of such sealing materials include seals such as gaskets, shaft seals, and valve stem seals, as well as non-contact or contact type packings such as self-sealing packings, piston rings, split ring type packings, mechanical seals, and oil seals, bellows, diaphragms, hoses, and tubes, as well as electrical wires, cushioning materials, vibration damping materials, and various sealing materials used in belt automatic transmission devices.

[0134] Specific applications in the above fuel system 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 breathing system manifolds, fuel filters, pressure regulating valves, canisters, fuel tank caps, fuel pumps, fuel tanks, fuel tank sender units, fuel injection devices, high-pressure fuel pumps, fuel line connector systems, pump timing control valves, suction control valves, solenoid subassemblies, fuel cut valves, etc.; canister purge solenoid valve seals, onboard refueling vapor recovery (ORVR) valve seals, fuel pump oil seals, fuel sender seals, fuel tank rollover valve seals, filler seals, injector seals, filler cap seals, filler cap valve seals; fuel hoses, Hoses such as fuel supply hoses, fuel return hoses, vapor (evaporator) hoses, vent (breather) hoses, filler hoses, filler neck hoses, hoses inside the fuel tank (in-tank hoses), carburetor control hoses, fuel inlet hoses, fuel breather hoses, etc.; gaskets used in fuel filters, fuel line connector systems, etc., and flange gaskets used in carburetors, etc.; line materials such as vapor recovery lines, fuel feed lines, vapor / ORVR lines, etc.; diaphragms used in canisters, ORVRs, fuel pumps, fuel tank pressure sensors, gasoline pumps, carburetor sensors, combined air control (CAC) systems, pulsation dampers, canister diaphragms, autococks, etc., and pressure regulator diaphragms for fuel injection systems; valves for fuel pumps, carburetor needle valves, rollover check valves, check valves, etc.; vents (breathers), tubes used inside fuel tanks; tank packings for fuel tanks, etc., packings for carburetor accelerator pump pistons; fuel sender vibration damping parts for fuel tanks;Examples include O-rings and diaphragms for controlling fuel pressure; accelerator pump cups; in-tank fuel pump mounts; injector cushion rings and seal rings for fuel injectors; needle valve core valves for carburetors; accelerator pump pistons for carburetors; valve seats for combined air control (CAC) systems; fuel tank bodies; and sealing components for solenoid valves.

[0135] Specific applications in the above-mentioned brake systems include: diaphragms used in master cylinders, hydraulic brake hoses, air brakes, and brake chambers of air brakes; hoses used in brake hoses, brake oil hoses, vacuum brake hoses, etc.; various sealing materials such as oil seals, O-rings, packings, and brake piston seals; atmospheric valves and vacuum valves for master cylinders, and check valves for brake valves; piston cups (rubber cups) and brake cups for master cylinders; boots for master cylinders and vacuum boosters of hydraulic brakes, and wheel cylinders of hydraulic brakes; and O-rings and grommets for anti-lock braking systems (ABS).

[0136] Specific examples of the above-mentioned basic electrical components include insulators and sheaths for electric wires (harnesses), tubes for harness exterior components, and grommets for connectors.

[0137] Specific applications in control system electrical components include insulation materials for various sensor wires.

[0138] Specific applications of the above-mentioned electrical components include O-rings and gaskets for car air conditioners, cooler hoses, high-pressure air conditioner hoses, air conditioner hoses, gaskets for electronic throttle units, plug boots for direct ignition systems, and diaphragms for distributors. It can also be used for bonding electrical components.

[0139] Specific applications in the above-mentioned intake and exhaust systems include packings used in intake manifolds, exhaust manifolds, etc., throttle body packings for throttles; diaphragms used in EGR (exhaust gas recirculation), pressure control (BPT), wastegates, turbo wastegates, actuators, actuators for variable turbine geometry (VTG) turbos, exhaust purification valves, etc.; hoses such as EGR control hoses, emission control hoses, turbo oil hoses (supply), turbo oil hoses (return), turbo air hoses, intercooler hoses, turbocharger hoses, hoses connected to the compressor of a turbo engine equipped with an intercooler, exhaust gas hoses, air intake hoses, turbo hoses, DPF (diesel particulate filter) sensor hoses, etc.; air ducts and turbo air ducts; intake manifold gaskets; EGR sealing materials, afterburn prevention valve seats for AB valves, turbine shaft seals (for turbochargers, etc.), and sealing members used in grooved parts such as rocker covers and air intake manifolds used in automobile engines.

[0140] Furthermore, it can be used in exhaust gas control components such as seals used in steam recovery canisters, catalytic converters, exhaust gas sensors, and oxygen sensors, as well as seals for solenoid armatures in steam recovery and steam canisters; and intake system manifold gaskets.

[0141] Furthermore, it can be used in diesel engine components such as O-ring seals for direct injection injectors, rotary pump seals, control diaphragms, fuel hoses, EGR, priming pumps, and boost compensator diaphragms. It can also be used in O-rings, seals, hoses, tubes, diaphragms, gaskets, and pipes used in urea SCR systems, as well as in the urea water tank body and seals for the urea water tank in urea SCR systems.

[0142] Specific examples of applications in the above-mentioned transmission system include transmission-related bearing seals, oil seals, O-rings, gaskets, and torque converter hoses. Other examples include transmission oil seals, automatic transmission oil hoses, ATF hoses, O-rings, and gaskets.

[0143] Transmissions include AT (Automatic Transmission), MT (Manual Transmission), CVT (Continuously Variable Transmission), and DCT (Dual-Clutch Transmission).

[0144] Other examples include oil seals, gaskets, O-rings, and packings for manual or automatic transmissions, as well as oil seals, gaskets, O-rings, and packings for continuously variable transmissions (belt-type or toroidal-type), 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).

[0145] Specific applications in steering systems include power steering oil hoses and high-pressure power steering hoses.

[0146] Examples of gaskets used in the engine body of an automobile engine include cylinder head gaskets, cylinder head cover gaskets, oil pan packings, general gaskets, O-rings, packings, seals such as timing belt cover gaskets, hoses such as control hoses, vibration-damping rubber for engine mounts, control valve diaphragms, and camshaft oil seals.

[0147] In the main moving systems of automobile engines, it can be used for shaft seals such as crankshaft seals and camshaft seals.

[0148] In the valve train of an automobile engine, it can be used in valve stem oil seals for engine valves, valve seats for butterfly valves, and so on.

[0149] In the lubrication and cooling systems of automobile engines, it can be used for engine oil cooler hoses, oil return hoses, and seal gaskets of engine oil coolers, as well as water hoses around the radiator, radiator seals, radiator gaskets, radiator O-rings, vacuum pump oil hoses of vacuum pumps, and other components such as radiator hoses, radiator tanks, oil pressure diaphragms, and fan coupling seals.

[0150] Thus, specific examples of its use in the automotive sector include engine head gaskets, oil pan gaskets, manifold packings, oxygen sensor seals, oxygen sensor bushings, and nitrogen oxides (NOx). x ) Sensor seal, nitrogen 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-combustion system seals and bearing seals, re-combustion system hoses, Carburetor sensor diaphragms, vibration damping rubber (engine mounts, exhaust sections, muffler hangers, suspension bushings, center bearings, strut bumper rubber, etc.), suspension vibration damping rubber (strut mounts, bushings, etc.), drivetrain vibration damping rubber (dampers, etc.), fuel hoses, EGR tubes and hoses, twin carb tubes, carburetor needle valve core valves, carburetor flange gaskets, oil hoses, oil cooler hoses, ATF hoses, cylinder head gaskets, water pump seals, gearbox seals, needle valve tips, reeds for motorcycle reed valves, oil seals for automobile engines, gasoline hose gun seals, seals for car air conditioners, rubber hoses for engine intercoolers, fuel line connector devices.Seals for systems, CAC valves, needle tips, engine wiring, filler hoses, car air conditioning O-rings, intake gaskets, fuel tank materials, distributor diaphragms, water hoses, clutch hoses, power steering hoses, automatic transmission hoses, master cylinder hoses, heater hoses, air conditioning hoses, ventilation hoses, oil filler caps, power steering rack seals, rack and pinion boots, CVJ boots, ball joint dust covers, strut dust covers, weatherstrips, glass runs, center unit gaskets, body side welts, bumper rubbers, 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 Examples include 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 system 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.

[0151] In the aircraft, space / rocket, and marine sectors mentioned above, it can be used particularly in fuel systems and lubrication systems.

[0152] In the aircraft sector, for example, these can be used as various aircraft seal components, various aircraft components for aircraft engine oil applications, jet engine valve stem seals, gaskets and O-rings, rotating shaft seals, hydraulic equipment gaskets, firewall seals, fuel supply hoses, gaskets and O-rings, aircraft cables, oil seals and shaft seals, etc.

[0153] In the aforementioned space and rocket fields, for example, it can be used as lip seals, diaphragms, and O-rings for spacecraft, jet engines, and missiles, as well as O-rings for gas turbine engine oils and vibration damping pads for missile ground control.

[0154] Furthermore, in the marine sector, it can be used, for example, as a stern seal for the propeller shaft of a screw, a valve stem seal for the intake and exhaust of a diesel engine, a valve seal for a butterfly valve, a valve seat and shaft seal for a butterfly valve, a shaft seal for a butterfly valve, a stern tube seal, fuel hoses, gaskets, O-rings for engines, marine cables, marine oil seals, and marine shaft seals.

[0155] In the chemical and pharmaceutical fields, such as the chemical plants mentioned above, and in the pharmaceutical fields, such as pharmaceuticals, it can be used in processes that require a high degree of chemical resistance, such as the processes for manufacturing chemicals like pharmaceuticals, pesticides, paints, and resins.

[0156] Specific applications in the above-mentioned chemical and pharmaceutical fields include: seals used in chemical equipment, chemical pumps and flow meters, chemical piping, heat exchangers, pesticide sprayers, pesticide transfer pumps, gas piping, fuel cells, analytical instruments and physicochemical instruments (e.g., column fittings for analytical instruments and instruments), shrink joints for flue gas desulfurization systems, nitric acid plants, power plant turbines, etc.; seals used in medical sterilization processes, plating solution seals, roller seals for papermaking belts, and wind tunnel joint seals; O-rings used in chemical equipment such as reactors and agitators, analytical instruments and instruments, chemical pumps, pump housings, valves, tachometers, etc., as well as O-rings for mechanical seals and compressor sealing; packings used in high-temperature vacuum dryers, tube joints of gas chromatography and pH meters, etc., and glass cooling systems for sulfuric acid production equipment. Examples include: instrument packing; diaphragms used in diaphragm pumps, analytical instruments, and scientific and chemical instruments; gaskets used in analytical instruments and instruments; ferrules used in analytical instruments and instruments; valve seats; U-cups; linings used in chemical equipment, gasoline tanks, wind tunnels, etc., and corrosion-resistant linings for anodized tanks; coatings for masking jigs for plating; valve components for analytical instruments and scientific and chemical instruments; expansion joints for flue gas desulfurization plants; acid-resistant hoses for concentrated sulfuric acid, etc., chlorine gas transfer hoses, oil-resistant hoses, rainwater drain hoses for benzene and toluene storage tanks; chemical-resistant tubes and medical tubes used in analytical instruments and scientific and chemical instruments; trichloroethylene-resistant rolls and dyeing rolls for textile dyeing; drug stoppers; medical rubber stoppers; chemical solution bottles, chemical solution tanks, bags, and chemical containers; and protective equipment such as gloves and boots that are resistant to strong acids and solvents.

[0157] In the fields of photography, such as developing machines; printing, such as printing presses; and painting, such as painting equipment, these can be used as rolls, belts, seals, valve components, etc., for dry-type photocopiers.

[0158] Specific applications in the fields of photography, printing, and painting include: the surface layer of the transfer rolls of photocopiers, the cleaning blades and belts of photocopiers; rolls and belts for office automation equipment such as photocopiers, printers, and facsimile machines (e.g., fuser rolls, crimping rolls, and pressure rolls); rolls, roll blades, and belts for PPC photocopiers; rolls for film developing machines and X-ray film developing machines; printing rolls, scrapers, tubes, valve components, and belts for printing machines; ink tubes, rolls, and belts for printers; painting rolls, scrapers, tubes, and valve components for coating and painting equipment; developing rolls, gravure rolls, guide rolls, guide rolls for magnetic tape manufacturing coating lines, gravure rolls for magnetic tape manufacturing coating lines, and coating rolls.

[0159] In the food equipment sector, including the aforementioned food plant equipment and household goods, it can be used in food manufacturing processes, or for food transfer or storage applications.

[0160] Specific applications in the food processing equipment field include seals for plate heat exchangers, solenoid valve seals for vending machines, packings for electric kettle bottles, sanitary pipe packings, packings for pressure cookers, seals for water heaters, gaskets for heat exchangers, diaphragms and packings for food processing equipment, and rubber materials for food processing machines (for example, heat exchanger gaskets, diaphragms, various seals such as O-rings, piping, hoses, sanitary packings, valve packings, and filling packings used as joints between the mouth of a bottle or other container and the filler during filling). Other applications 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, and various automatic food vending machines.

[0161] In the field of nuclear power plant equipment mentioned above, it can be used for check valves and pressure reducing valves around the reactor, as well as seals in uranium hexafluoride enrichment equipment.

[0162] Specific applications in the above-mentioned 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 lubrication machinery; sealing materials used in mandrels, etc.; seals used in windows of dry cleaning equipment, etc.; seals for cyclotrons and (vacuum) valve seals; seals for proton accelerators; seals for automatic packaging machines; diaphragms for pumps used in sulfur dioxide and chlorine gas analyzers (pollution measuring instruments) in the air; snake pump linings; rolls and belts for printing presses; conveyor belts; pressing rolls for pickling steel plates, etc.; cables for robots; solvent pressing rolls for aluminum rolling lines, etc.; O-rings for couplers; acid-resistant cushioning materials; dust seals and lip rubbers for sliding parts of cutting machines; gaskets for food waste incinerators; friction materials; surface modifiers and coatings for metals or rubber. Furthermore, it can be used as gaskets and sealants for equipment used in the papermaking process, as a sealant for cleanroom filter units, as a sealing agent for buildings, as a protective coating agent for concrete and cement, as a glass cloth impregnation material, as a processing aid for polyolefins, as an additive to improve the moldability of polyethylene, as a fuel container for small generators and lawnmowers, and as pre-coated metal obtained by priming metal plates. In addition, it can be impregnated into woven fabrics and baked to be used as sheets and belts.

[0163] Specific examples of its use in the steel industry include sheet metal processing rolls in sheet metal processing equipment.

[0164] Specific applications in the electrical field include insulating oil caps for Shinkansen bullet trains, venting seals for liquid-sealed transformers, seals for transformers, jackets for oil well cables, seals for ovens such as electric furnaces, window frame seals for microwave ovens, sealant used when bonding the wedge and neck of a CRT, sealant for halogen lamps, fixing agent for electrical components, sealant for end treatment of sheathed heaters, and sealant used for insulating and moisture-proofing the terminals of electrical equipment lead wires. It can also be used as a covering material for oil-resistant and heat-resistant wires, high-temperature resistant wires, chemical-resistant wires, high-insulation wires, high-voltage transmission lines, cables, wires used in geothermal power generation equipment, and 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 in electrical insulating materials (for example, insulating spacers for various electrical equipment, insulating tapes used for cable joints and ends, and materials used in heat-shrinkable tubing) and electrical and electronic equipment materials used in high-temperature atmospheres (for example, lead wire materials for motors, and wire materials around high-temperature furnaces). It can also be used in the encapsulation layer and protective film (backsheet) of solar cells.

[0165] In the fuel cell field mentioned above, it 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 a seal, packing, and separator for piping for hydrogen, oxygen, generated water, etc.

[0166] In the field of electronic components mentioned above, it can be used as a raw material for heat dissipation materials, a raw material for electromagnetic wave shielding materials, a gasket for computer hard disk drives (magnetic recording devices), and the like. Furthermore, it is used as a buffer rubber (crush 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 (electroluminescent elements), a binder for electrode active materials in capacitors, a encapsulant, a sealing agent, a coating material for quartz in optical fibers, a coating material for optical fibers, and other films and sheets; for electronic components such as CMOS electronic circuits, transistors, integrated circuits, organic transistors, light-emitting elements, actuators, memory, sensors, coils, capacitors, and resistors; for potting, coating, and adhesive sealing of circuit boards; as a fixing agent for electronic components; as a modifier for encapsulants such as epoxy; as a coating agent for printed circuit boards; as a modifier for printed wiring board prepreg resins such as epoxy; as a shatterproof material for light bulbs, etc.; for computer gaskets; for large computer cooling hoses; for secondary batteries, especially for lithium secondary batteries, gaskets and O-rings; as a sealing layer covering one or both sides of the outer surface of organic EL structures; as a connector; and as a damper.

[0167] In the field of chemical transport equipment mentioned above, it can be used in safety valves and loading valves for trucks, trailers, tank trucks, ships, etc.

[0168] In the field of equipment components for the exploration and extraction of energy resources such as oil and gas, these materials are used as various sealing materials used during the extraction of oil and natural gas, and as boots for electrical connectors used in oil wells.

[0169] Specific applications in the field of energy resource exploration and mining equipment components include drill bit seals, pressure regulating diaphragms, seals for horizontal drilling motors (stators), stator bearing (shaft) seals, seals used in blowout prevention devices (BOPs), seals used in rotary blowout prevention devices (pipe wipers), seals and gas-liquid connectors used in MWDs (Real-time Drilling Information Detection Systems), logging tool seals used in logging equipment (e.g., O-rings, seals, packings, gas-liquid connectors, boots, etc.), expansion packers and completion packers and packer seals used therein, seals and packings used in cementing equipment, and perforators. Examples include seals used in drilling equipment, seals, packings and motor linings used in mud pumps, underground audible detector covers, U-cups, composition seating cups, rotary seals, laminated elastomeric bearings, flow control seals, sand volume control seals, safety valve seals, seals for hydraulic fracturing equipment, seals and packings for linear packers and linear hangers, seals and packings for well heads, seals and packings for chokes and valves, sealing materials for LWD (Logging During 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.

[0170] In addition, it can be used for joint sealing in kitchens, bathrooms, and washrooms; tents for outdoor tents; seals for stamping materials; rubber hoses for gas heat pumps and CFC-resistant rubber hoses; agricultural films, linings, and weather-resistant covers; and tanks made of laminated steel plates used in construction, home appliances, and other fields.

[0171] Furthermore, it can also be used in articles that are combined with metals such as aluminum. Examples of such uses include door seals, gate valves, pendulum valves, solenoid tips, as well as metal-rubber parts combined with metal, such as piston seals, diaphragms, and metal gaskets.

[0172] It can also be used for rubber parts, brake shoes, brake pads, and other components in bicycles.

[0173] Furthermore, the molded product can be applied to belts.

[0174] Examples of belts include: power transmission belts (including flat belts, V-belts, V-ribbed belts, toothed belts, etc.), conveyor belts, flat belts used in various high-temperature areas such as around engines in agricultural machinery, machine tools, and industrial machinery; conveyor belts for transporting bulk and granular materials such as coal, crushed stone, soil, ore, and wood chips in high-temperature environments; conveyor belts used in steel mills such as blast furnaces; conveyor belts used in applications exposed to high-temperature environments in precision equipment assembly plants, food processing plants, etc.; V-belts and V-ribbed belts for agricultural machinery, general equipment (e.g., office automation equipment, printing machines, commercial dryers, etc.), and automobiles; power transmission belts for transport robots; toothed belts for food processing machinery and machine tool power transmission belts; and toothed belts used in automobiles, office automation equipment, medical equipment, printing machines, etc.

[0175] In particular, timing belts are a typical example of toothed belts used in automobiles.

[0176] The above belt may have a single-layer structure or a multi-layer structure.

[0177] In the case of a multilayer structure, the belt may consist of a layer obtained by crosslinking a fluororubber crosslinking composition and a layer made of other materials.

[0178] In a multilayer belt, other layers may include layers made of other rubbers, layers made of thermoplastic resins, various fiber reinforcement layers, canvas, and metal foil layers.

[0179] The molded products can also be used in industrial vibration damping pads, vibration damping mats, railway slab mats, pads, and automotive vibration damping rubber. Examples of automotive vibration damping rubber include those for engine mounts, motor mounts, member mounts, strut mounts, bushings, dampers, muffler hangers, and center bearings.

[0180] Other applications include joint components such as flexible joints and expansion joints, boots, and grommets. In the marine sector, for example, marine pumps are another example.

[0181] Joint members are fittings used in piping and piping systems, and are used for purposes such as preventing vibrations and noise generated from piping systems, absorbing expansion and displacement due to temperature and pressure changes, absorbing dimensional changes, and mitigating and preventing the effects of earthquakes and ground subsidence.

[0182] Flexible joints and expansion joints can be preferably used as complex-shaped molded products for applications such as shipbuilding piping, mechanical piping for pumps and compressors, chemical plant piping, electrical piping, civil engineering and water supply piping, and automobiles. Boots can be preferably used as complex-shaped molded bodies for various industrial applications, such as automotive boots including constant velocity joint boots, dust covers, rack and pinion steering boots, pin boots, and piston boots; boots for agricultural machinery; boots for industrial vehicles; boots for construction machinery; boots for hydraulic machinery; boots for pneumatic machinery; boots for centralized lubrication systems; boots for liquid transfer systems; boots for fire fighting; and boots for various liquefied gas transfer systems.

[0183] The molded parts can also be used for diaphragms in filter presses, blowers, water supply systems, liquid storage tanks, pressure switches, accumulators, and air springs in suspensions, etc.

[0184] By adding the molded product to rubber or resin, an anti-slip agent can be obtained that provides a molded product or coating film that is less slippery in wet environments such as rain, snow, ice, or sweat.

[0185] Furthermore, the molded product can also be used as a cushioning material for hot press molding when manufacturing decorative plywood, printed circuit boards, electrical insulating boards, rigid polyvinyl chloride laminates, etc., using materials such as melamine resin, phenolic resin, and epoxy resin.

[0186] The molded products can also contribute to the impermeability of various supports, such as sealing gaskets for weapons and protective clothing against contact with invasive chemicals.

[0187] Furthermore, it can be used in various sealing materials such as O-rings, V-rings, X-rings, packings, gaskets, diaphragms, oil seals, bearing seals, lip seals, plunger seals, door seals, lip and face seals, gas delivery plate seals, wafer support seals, barrel seals, and other sealing materials used to seal and seal lubricating oils (engine oil, transmission oil, gear oil, etc.), fuel oils, and greases (especially urea-based greases) that contain amine-based additives (especially amine-based additives used as antioxidants and detergent dispersants) used in transportation equipment such as automobiles and ships. It 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.

[0188] This heat- and oil-resistant wire coating material is used for lead wires of sensors that come into contact with the transmission oil and / or engine oil of internal combustion engines in automobiles and other vehicles to detect the oil temperature and / or pressure. It can also be used in high-temperature oil atmospheres such as those found in automatic transmissions and engine oil pans.

[0189] In addition, molded products may be used with a vulcanized coating. Specifically, these applications include non-stick oil-resistant rolls for photocopiers, weatherstripping for preventing weather-induced de-icing, rubber stoppers for intravenous fluids, rubber stoppers for vials, mold release agents, non-stick light conveyor belts, anti-stick coatings for gaskets on automobile engine mounts, coating of synthetic fibers, and bolt members or joints with a thin packing coating layer.

[0190] Furthermore, the use of molded products in automotive-related parts also includes use in motorcycle parts with similar structures.

[0191] Furthermore, examples of fuels used in the automotive industry include diesel fuel, gasoline, and diesel engine fuel (including biodiesel fuel).

[0192] The molded parts can also be used as sealing components for rolling bearings.

[0193] Examples of the rolling bearings mentioned above include ball bearings, roller bearings, bearing units, and linear bearings.

[0194] Examples of ball bearings include radial ball bearings, thrust ball bearings, and thrust angular contact ball bearings.

[0195] Examples of radial ball bearings include deep groove ball bearings, angular contact ball bearings, four-point contact ball bearings, and self-aligning ball bearings.

[0196] The deep groove ball bearings described above are used, for example, in electric motors, household electrical appliances, office automation equipment, and the like.

[0197] The angular contact ball bearings mentioned above include single-row angular contact ball bearings, combined angular contact ball bearings, and double-row angular contact ball bearings. Single-row angular contact ball bearings are used in electric motors, household electrical appliances, office automation equipment, and hydraulic pumps and vertical pumps that are subjected to axial loads in addition to radial loads. Combined angular contact ball bearings are used in the spindles and grinding spindles of machine tools where improved rotational accuracy and increased rigidity of the shaft are required. Double-row angular contact ball bearings are used in electromagnetic clutches for automobile air conditioners, etc.

[0198] The above-mentioned four-point contact ball bearing is used in speed reducers and other devices where axial loads are applied from both directions and there is limited space for the bearing width.

[0199] The above-mentioned self-aligning ball bearing is used in locations where it is difficult to align the shaft and housing, or in transmission shafts where the shaft is prone to bending.

[0200] The thrust ball bearings described above include single thrust ball bearings and double thrust ball bearings, and these ball bearings are applicable to conventionally known applications in which they are used.

[0201] The above-mentioned thrust angular contact ball bearing is used in combination with a double-row cylindrical roller bearing as an axial load bearing for the spindle of a machine tool.

[0202] Examples of the roller bearings mentioned above include radial roller bearings and thrust roller bearings.

[0203] Examples of radial roller bearings include cylindrical roller bearings, needle roller bearings, tapered roller bearings, and self-aligning roller bearings.

[0204] The above-mentioned cylindrical roller bearings are used in general machinery, machine tools, electric motors, speed reducers, railway axles, aircraft, and the like.

[0205] Needle roller bearings are used in general machinery, automobiles, electric motors, etc.

[0206] Tapered roller bearings are used in machine tools, automobile and railway axles, rolling mills, speed reducers, and the like.

[0207] Self-aligning roller bearings are used in general machinery, rolling mills, papermaking machinery, axles, etc.

[0208] Examples of the thrust roller bearings mentioned above include thrust cylindrical roller bearings, thrust needle roller bearings, thrust tapered roller bearings, and thrust self-aligning roller bearings.

[0209] Thrust cylindrical roller bearings are used in machine tools, general machinery, etc.

[0210] Thrust needle roller bearings are used in automobiles, pumps, general machinery, etc.

[0211] Thrust tapered roller bearings are used in general machinery, rolling mills, and the like.

[0212] Thrust self-aligning roller bearings are used in cranes, extruders, general machinery, etc.

[0213] In addition to being used as molded products after crosslinking, fluororubber crosslinking compositions can also be used as various components in various industrial fields. Therefore, the applications of fluororubber crosslinking compositions will be explained next.

[0214] Fluororubber crosslinking compositions can be used as surface modifiers for metals, rubber, plastics, glass, etc.; as sealing and coating materials requiring heat resistance, chemical resistance, oil resistance, and non-stick properties, such as metal gaskets and oil seals; as non-stick coating materials or bleed barriers for rolls and belts for office automation equipment; and for impregnation and baking coating of woven sheets and belts.

[0215] By making the fluororubber crosslinking composition highly viscous and highly concentrated, it can be used as a sealant, lining, or sealant for complex shapes using conventional methods. By making it highly viscous, it can be used to form thin films of several microns in thickness. By making it highly viscous, it can be used for coating pre-coated metals, O-rings, diaphragms, and reed valves.

[0216] Furthermore, it can be used for coating woven fabrics, paper sheets, conveying rolls or belts, printing belts, chemical-resistant tubes, chemical stoppers, fuel hoses, and more.

[0217] Suitable substrates for articles coated with fluororubber crosslinking compositions include metals such as iron, stainless steel, copper, aluminum, and brass; glass products such as glass plates, glass fiber woven fabrics, and nonwoven fabrics; molded articles and coatings of general-purpose and heat-resistant resins such as polypropylene, polyoxymethylene, polyimide, polyamideimide, polysulfone, polyethersulfone, and polyetheretherketone; molded articles and coatings 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 of natural and synthetic fibers.

[0218] Coatings formed from fluororubber crosslinking compositions can be used in fields requiring heat resistance, solvent resistance, lubricity, and non-stick properties. Specific applications include rolls (e.g., fixing rolls, crimping rolls) and conveyor belts for office automation equipment such as photocopiers, printers, and fax machines; sheets and belts; O-rings, diaphragms, chemical-resistant tubes, fuel hoses, valve seals, chemical plant gaskets, and engine gaskets.

[0219] Fluororubber crosslinking compositions can also be dissolved in solvents and used as paints and adhesives. Furthermore, they can be used as emulsified dispersions (latex) and as paints.

[0220] Fluororubber crosslinking compositions are used as sealing materials and linings for various devices and piping, and as surface treatment agents for structures made of inorganic and organic substrates such as metal, ceramics, glass, stone, concrete, plastic, rubber, wood, paper, and fibers.

[0221] Fluororubber crosslinking compositions can be applied to substrates and the like by dispenser coating or screen printing coating.

[0222] Fluororubber crosslinking compositions may be used as coating compositions for casting films or for dipping substrates such as fabrics, plastics, metals, or elastomers.

[0223] In particular, fluororubber crosslinking compositions may be used in the form of latex to manufacture coating fabrics, protective gloves, impregnated fibers, O-ring coatings, coatings for fuel system quick-connect O-rings, coatings for fuel system seals, coatings for fuel tank rollover valve diaphragms, coatings for fuel tank pressure sensor diaphragms, coatings for oil filters and fuel filter seals, coatings for fuel tank sender seals and sender head fitting seals, coatings for copier fixing mechanism rolls, and polymer coating compositions.

[0224] They are useful for coating silicone rubber, nitrile rubber, and other elastomers. They are also useful for coating parts manufactured from such elastomers, for the purpose of improving both the permeability and chemical resistance of the base elastomer, as well as its thermal stability. Other applications include coatings for heat exchangers, expansion joints, butts, tanks, fans, flue ducts and other conduits, as well as for housing structures, such as concrete housing structures. Fluororubber crosslinking compositions may be applied to exposed cross-sections of multilayer component structures, for example, in the manufacturing of hose structures and diaphragms. Sealing members in connections and joints often consist of rigid materials, and fluororubber crosslinking compositions provide improved frictional interfaces, enhanced dimensional interference fits with reduced trace leakage along the sealing surface. Their latex enhances seal durability in various automotive system applications.

[0225] They can also be used in the manufacture of power steering systems, fuel systems, air conditioning systems, and any joints where hoses and tubes connect to other parts. A further useful application of fluororubber crosslinking compositions is in the repair of manufacturing defects (and damage due to use) in multilayer rubber structures such as three-ply fuel hoses. Fluororubber crosslinking compositions are also useful in coating thin steel sheets that can be formed or embossed before or after paint application. For example, multiple layers of coated steel can be assembled to form a gasket between two rigid metal members. The sealing effect is obtained by applying the fluororubber crosslinking composition between the layers. This process can be used to manufacture engine head gaskets and exhaust manifold gaskets for the purpose of reducing bolt force and strain in assembled parts, while providing good fuel savings and low emissions due to low crack, deflection, and hole strain.

[0226] The fluororubber crosslinking composition can also be used as a coating agent; a substrate-integrated gasket or packing formed by dispenser molding onto a substrate containing inorganic materials such as metal or ceramic; or a multilayer product coated onto a substrate containing inorganic materials such as metal or ceramic.

[0227] The fluororubber crosslinking composition is suitable as a lightweight and flexible wiring material for electronic devices and can be used in known electronic components. Examples of electronic components include CMOS electronic circuits, transistors, integrated circuits, organic transistors, light-emitting elements, actuators, memories, sensors, coils, capacitors, and resistors. By using this, flexible electronic devices such as solar cells, various displays, sensors, actuators, electronic artificial skin, sheet-type scanners, braille displays, and wireless power transmission sheets can be obtained.

[0228] Although embodiments have been described above, it should be understood that various modifications to the form and details are possible without departing from the spirit and scope of the claims.

[0229] <1> According to the first aspect of this disclosure, It contains fluororubber (a), additives (b), hydrofluoricating agent (c), crosslinking agent (d), organic peroxide (e), and co-crosslinking agent (f), Additive (b) is At least one selected from the group consisting of silver compounds and copper compounds, The crosslinking agent (d) A compound having at least one hydroxyl group (d1), Onium salt of compound (d1), Alkali metal salt of compound (d1), Alkaline earth metal salts of compound (d1), and, Esters derived from compound (d1) and carboxylic acid It is at least one selected from the group consisting of the following: A composition for crosslinking fluororubber is provided. <2> According to the second aspect of this disclosure, A fluororubber crosslinking composition is provided in which additive (b) is a silver compound. <3> According to the third aspect of this disclosure, A fluororubber crosslinking composition is provided in a first or second view, wherein additive (b) is at least one selected from the group consisting of silver(I) oxide and silver(II) oxide. <4> According to the fourth aspect of this disclosure, A fluororubber crosslinking composition is provided in which additive (b) is a copper compound. <5> According to the fifth aspect of this disclosure, A fluororubber crosslinking composition is provided in a first or second view, wherein additive (b) is at least one selected from the group consisting of copper(I) oxide and copper(II) oxide. <6> According to the sixth aspect of this disclosure, A fluororubber crosslinking composition is provided, wherein the content of additive (b) is 0.1 to 10 parts by mass per 100 parts by mass of fluororubber (a), according to any of the first to fifth views. <7> According to the seventh aspect of this disclosure, A fluororubber crosslinking composition is provided in which fluororubber (a) contains vinylidene fluoride units according to any of the first to sixth views. <8> According to the eighth aspect of this disclosure, A fluororubber crosslinking composition is provided, wherein the fluororubber (a) is a peroxide crosslinkable fluororubber. <9> According to the ninth aspect of this disclosure, A fluororubber crosslinking composition is provided, wherein the fluororubber (a) has iodine atoms, according to any of the first to eight views. <10> According to the tenth aspect of this disclosure, A fluororubber crosslinking composition is provided, according to any one of the first to ninth views, wherein the hydrofluoricating agent (c) is at least one selected from the group consisting of quaternary ammonium salts and quaternary phosphonium salts. <11> According to the eleventh aspect of this disclosure, A fluororubber crosslinking composition is provided according to any one of the first to tenth viewpoints, wherein the crosslinking agent (d) is at least one selected from the group consisting of compound (d1) and onium salts of compound (d1). <12> According to the 12th aspect of this disclosure, A fluororubber crosslinking composition is provided, according to any of the first to eleventh views, wherein the crosslinking agent (d) content is 0.1 to 10 parts by mass per 100 parts by mass of fluororubber (a). <13> According to the 13th aspect of this disclosure, A fluororubber crosslinking composition is provided, wherein the content of organic peroxide (e) is 0.05 to 10 parts by mass per 100 parts by mass of fluororubber (a), according to any of the first to twelfth views. <14> According to the fourteenth aspect of this disclosure, A fluororubber crosslinking composition is provided in which the co-crosslinking agent (f) is a co-crosslinking agent for peroxide crosslinking, according to any of the first to thirteenth views. <15> According to the 15th aspect of this disclosure, There is provided a fluororubber crosslinking composition according to any one of the first to fourteenth aspects, wherein the co-crosslinking agent (f) is triallyl isocyanurate. <16> According to the sixteenth aspect of the present disclosure, There is provided a fluororubber crosslinking composition according to any one of the first to fifteenth aspects, wherein the content of the co-crosslinking agent (f) is 0.1 to 10 parts by mass with respect to 100 parts by mass of the fluororubber (a). <17> According to the seventeenth aspect of the present disclosure, There is provided a fluororubber crosslinking composition according to any one of the first to sixteenth aspects, further containing an acid acceptor (g), wherein the content of the acid acceptor (g) is 0.1 to 50 parts by mass with respect to 100 parts by mass of the fluororubber (a). <18> According to the eighteenth aspect of the present disclosure, There is provided a molded product obtained from the fluororubber crosslinking composition according to any one of the first to seventeenth aspects.

Examples

[0230] Next, embodiments of the present disclosure will be described with reference to examples, but the present disclosure is not limited to such examples.

[0231] Each numerical value in the examples was measured by the following method.

[0232] <Monomer composition of fluororubber> 19 Measured using F-NMR (AC300P type manufactured by Bruker).

[0233] <Fluorine content> 19 Determined by calculation from the composition of the fluororubber measured by F-NMR.

[0234] <Mooney viscosity> Measured in accordance with ASTM D1646-15 and JIS K6300-1:2013. The measurement temperature was 100°C.

[0235] <Glass transition temperature (Tg)> Using a differential scanning calorimeter (DSC822e manufactured by Mettler Toledo or X-DSC7000 manufactured by Hitachi High-Tech Sciences), a DSC curve was obtained by heating 10 mg of the sample at a rate of 20 °C / min. The temperature indicated by the intersection of the extension of the baseline before and after the secondary transition of the DSC curve and the tangent line at the inflection point of the DSC curve was defined as the glass transition temperature.

[0236] <Heat of fusion> Using a differential scanning calorimeter (DSC822e manufactured by Mettler Toledo or X-DSC7000 manufactured by Hitachi High-Tech Sciences), a DSC curve was obtained by heating 10 mg of the sample at a rate of 20 °C / min. The heat of fusion was calculated from the magnitude of the melting peak (ΔH) that appeared in the DSC curve.

[0237] <Iodine content> Na2CO3 and K2CO3 were mixed at a 1:1 (weight ratio), and the resulting mixture was dissolved in 20 ml of pure water to prepare an absorption solution. 5 mg of Na2SO3 was mixed with 12 mg of the sample (fluororubber) to prepare a mixture, which was burned in oxygen in a quartz flask, and the generated combustion gas was introduced into the absorption solution. After leaving the obtained absorption solution standing for 30 minutes, the concentration of iodine ions in the absorption solution was measured using a Shimadzu 20A ion chromatograph. The iodine ion content was determined using a calibration curve prepared using a KI standard solution containing 0.5 ppm of iodine ions and a KI standard solution containing 1.0 ppm of iodine ions.

[0238] <Crosslinking characteristics (maximum torque (MH), optimum crosslinking time (T90))> Regarding the fluororubber crosslinking composition, during the primary crosslinking, a crosslinking curve was obtained at the temperatures described in each table using a vulcanization tester (MDR H2030 manufactured by M & K), and the maximum torque (MH) and the optimum crosslinking time (T90) were determined from the change in torque. The higher the maximum torque (MH), the higher the crosslinking density.

[0239] <Tensile strength and elongation at break> A dumbbell-shaped test specimen (No. 6) was prepared using a 2 mm thick cross-linked sheet. The obtained test specimen and a tensile testing machine (Tensilon RTG-1310, A&D Corporation) were used to measure the tensile strength and elongation at break at 23°C under conditions of 500 mm / min, in accordance with JIS K6251:2010.

[0240] <Hardness> Three 2mm thick cross-linked sheets were stacked, and the durometer hardness (Type A, peak value) was measured in accordance with JIS K6251-3:2012.

[0241] <Compression permanent set> Using small test specimens for compression set measurement, the measurement was performed according to Method A of JIS K6262:2013, with a compressibility of 25%, a test temperature of 200°C, and a test duration of 72 hours.

[0242] The following materials were used in the examples and comparative examples. Fluororubber A: Molar ratio of vinylidene fluoride / hexafluoropropylene: 78 / 22 Fluorine content: 66% Mooney viscosity (ML1+10 (100℃)): 60 Glass transition temperature: -18℃ Heat of fusion: Not observed in the second run. Iodine content: 0.17% by mass

[0243] MT Carbon (N2SA: 8m) 2 ( / g, DBP: 43ml / 100g) Crosslinking agent A: Bisphenol AF Crosslinking agent B: 3',5'-dihydroxyacetophenone Hydrofluoride removal agent A: A mixture of 91% by mass of benzyldimethyloctadecylammonium chloride and 9% by mass of isopropyl alcohol. Co-crosslinking agent A: Triallyl isocyanurate Organic peroxide A: 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane Calcium hydroxide Magnesium oxide Silver(I) oxide: Obtained from Fujifilm Wako Pure Chemical Corporation Copper(I) oxide: Obtained from Fujifilm Wako Pure Chemical Corporation Copper(II) oxide: Obtained from Fujifilm Wako Pure Chemical Corporation Silver(II) oxide: Obtained from Fujifilm Wako Pure Chemical Corporation

[0244] Examples 1 - 10, Comparative Examples 1 - 3 According to the formulations described in each table, the components of each example and each comparative example were blended and kneaded on an open roll to prepare a fluororubber crosslinking composition. The maximum torque (MH) and optimum crosslinking time (T90) of the obtained fluororubber crosslinking composition are shown in each table. Next, the fluororubber crosslinking composition was crosslinked by primary crosslinking (press crosslinking) under the conditions described in each table and secondary crosslinking (oven crosslinking) under the conditions described in each table to obtain a crosslinked sheet (thickness 2 mm) and small test pieces for measuring compression set. The evaluation results of the obtained crosslinked sheet and the results of the compression set test are shown in each table.

[0245] [Table 1]

[0246] [Table 2]

[0247] [Table 3]

Claims

1. It contains fluororubber (a), additives (b), hydrofluoricating agent (c), crosslinking agent (d), organic peroxide (e), and co-crosslinking agent (f), Additive (b) It is at least one selected from the group consisting of silver(I) oxide, silver(II) oxide, copper(I) oxide, and copper(II) oxide. The crosslinking agent (d) A compound (d1) having two or more hydroxyl groups, or one hydroxyl group and one alkylcarbonyloxy group. Onium salt of compound (d1), Alkali metal salts of compound (d1), and Alkaline earth metal salt of compound (d1) It is at least one selected from the group consisting of the following: Composition for crosslinking fluororubber.

2. The fluororubber crosslinking composition according to claim 1, wherein additive (b) is at least one selected from the group consisting of silver(I) oxide and silver(II) oxide.

3. The fluororubber crosslinking composition according to claim 1, wherein additive (b) is at least one selected from the group consisting of copper(I) oxide and copper(II) oxide.

4. The fluororubber crosslinking composition according to any one of claims 1 to 3, wherein the content of additive (b) is 0.1 to 10 parts by mass per 100 parts by mass of fluororubber (a).

5. A fluororubber crosslinking composition according to any one of claims 1 to 3, wherein the fluororubber (a) comprises vinylidene fluoride units.

6. A fluororubber crosslinking composition according to any one of claims 1 to 3, wherein the fluororubber (a) is a fluororubber that can be crosslinked with peroxide.

7. A fluororubber crosslinking composition according to any one of claims 1 to 3, wherein the fluororubber (a) has an iodine atom.

8. The fluororubber crosslinking composition according to any one of claims 1 to 3, wherein the hydrofluoricating agent (c) is at least one selected from the group consisting of quaternary ammonium salts and quaternary phosphonium salts.

9. A fluororubber crosslinking composition according to any one of claims 1 to 3, wherein the crosslinking agent (d) is at least one selected from the group consisting of compound (d1) and onium salts of compound (d1).

10. The fluororubber crosslinking composition according to any one of claims 1 to 3, wherein the crosslinking agent (d) is contained in an amount of 0.1 to 10 parts by mass per 100 parts by mass of fluororubber (a).

11. A fluororubber crosslinking composition according to any one of claims 1 to 3, wherein the content of organic peroxide (e) is 0.05 to 10 parts by mass per 100 parts by mass of fluororubber (a).

12. A fluororubber crosslinking composition according to any one of claims 1 to 3, wherein the co-crosslinking agent (f) is a co-crosslinking agent for peroxide crosslinking.

13. A fluororubber crosslinking composition according to any one of claims 1 to 3, wherein the co-crosslinking agent (f) is triallyl isocyanurate.

14. The fluororubber crosslinking composition according to any one of claims 1 to 3, wherein the content of the co-crosslinking agent (f) is 0.1 to 10 parts by mass per 100 parts by mass of fluororubber (a).

15. A fluororubber crosslinking composition according to any one of claims 1 to 3, further containing an acid acceptor (g), wherein the content of the acid acceptor (g) is 0.1 to 50 parts by mass per 100 parts by mass of fluororubber (a).

16. A molded article obtained from a fluororubber crosslinking composition according to any one of claims 1 to 3.

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