Fluororubber crosslinking composition, molded article, and sealing material

Abstract

This invention provides a composition for crosslinking fluororubber, comprising a fluororubber (a) capable of polyol crosslinking and a crosslinking agent (b), wherein the crosslinking agent (b) is at least one selected from the group consisting of a compound represented by the following general formula (b) and a salt of the compound with an alkali metal, alkaline earth metal, or onium compound. (The symbols are as described in the specification.)

Description

Technical Field

[0001] This invention relates to compositions for crosslinking fluororubber, molded articles, and sealing materials. Background Technology

[0002] Patent Document 1 describes an aromatic polyhydroxy compound that can function as a crosslinking agent or auxiliary curing agent for fluorinated elastomers as an essential component in the final cured composition. One of the most useful aromatic polyphenols is a bisphenol compound known as hexafluoroisopropylidene-bis(4-hydroxybenzene) as bisphenol AF.

[0003] Patent Document 2 describes a composition comprising a fluorocarbon elastomer rubber, a fluoroaliphatic sulfonamide as a curing agent thereto, and a second curing agent selected from the group consisting of polyhydroxy compounds, polyamine compounds and their derivatives.

[0004] Patent document 3 discloses a composition comprising a fluorocarbon elastomer rubber and a vulcanizing agent thereof, characterized in that the vulcanizing agent is a composition comprising one or a mixture of aromatic compounds having hydroxyl and oxyallyl groups directly bonded to the carbon atom of an aromatic ring.

[0005] Patent document 4 discloses a composition for the vulcanization of fluororubber, comprising (a) a fluorinated elastomer; (b) one or more substances selected from the group consisting of divalent metal oxides, divalent metal hydroxides, and mixtures of such metal oxides or metal hydroxides with metal salts of weak acids; (c) a polyhydroxy aromatic compound; and (d) a specific vulcanization accelerator.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Publication No. 64-418

[0009] Patent Document 2: Japanese Patent Application Publication No. 60-215042

[0010] Patent Document 3: Japanese Patent Application Publication No. 59-105046

[0011] Patent Document 4: Japanese Patent Application Publication No. 63-268757 Summary of the Invention

[0012] The problem that the invention aims to solve

[0013] The purpose of this invention is to provide a composition for crosslinking fluororubber, which contains a compound without fluorine atoms as a crosslinking agent, and can produce molded articles with excellent compression set characteristics, tensile strength and heat resistance at high temperatures.

[0014] Methods for solving problems

[0015] According to the present invention, a composition for crosslinking fluororubber is provided, comprising a fluororubber (a) capable of polyol crosslinking and a crosslinking agent (b), wherein the crosslinking agent (b) is at least one selected from the group consisting of a compound represented by the following general formula (b) and a salt of the compound with an alkali metal, an alkaline earth metal or an onium compound.

[0016] [Chemistry 1]

[0017]

[0018] (In the formula, m and n independently represent integers from 1 to 3; the hydrogen atoms bonded to the four benzene rings can be replaced by any substituents (excluding hydroxyl, thioalkyl, amino, acid groups, halogen atoms and groups containing halogen atoms).)

[0019] In the fluororubber crosslinking composition of the present invention, the fluororubber (a) preferably contains vinylidene fluoride units.

[0020] In the fluororubber crosslinking composition of the present invention, the content of crosslinking agent (b) is preferably 0.5 mmol to 50 mmol relative to 100 parts by weight of fluororubber (a).

[0021] The fluororubber crosslinking composition of the present invention preferably further contains a crosslinking accelerator (c).

[0022] The fluororubber crosslinking composition of the present invention preferably further contains an acid acceptor (d).

[0023] The fluororubber crosslinking composition of the present invention preferably contains 0.1 to 50 parts by weight of an acid acceptor (d) relative to 100 parts by weight of fluororubber (a).

[0024] The fluororubber crosslinking composition of the present invention preferably further contains at least one acid acceptor (d) selected from the group consisting of metal oxides, metal hydroxides, alkali metal silicates, metal salts of weak acids and hydrotalcite.

[0025] In the fluororubber crosslinking composition of the present invention, the crosslinking agent (b) is preferably selected from at least one of the following groups: a compound represented by the following formula (b1) and a salt of the compound and an alkali metal, alkaline earth metal or onium compound.

[0026] [Chemistry 2]

[0027]

[0028] In addition, according to the present invention, a molded article or sealing material obtained from the above-described fluororubber crosslinking composition is provided.

[0029] The effects of the invention

[0030] According to the present invention, a composition for crosslinking fluororubber can be provided, which contains a compound without fluorine atoms as a crosslinking agent, and can obtain molded articles with excellent compression set characteristics, tensile strength and heat resistance at high temperatures. Detailed Implementation

[0031] The specific embodiments of the present invention will be described in detail below, but the present invention is not limited to the following embodiments.

[0032] The fluororubber crosslinking composition of the present invention contains a fluororubber (a) capable of polyol crosslinking and a crosslinking agent (b).

[0033] By using a crosslinking composition containing bisphenol AF as a crosslinking agent, molded articles with excellent compression set properties at high temperatures can be obtained. However, if bisphenol AF adheres to equipment used for metering or composition preparation, since bisphenol AF is a fluorine-containing compound, cleaning the adhered bisphenol AF and treating the resulting substances requires specialized incineration equipment, resulting in significant cost. Therefore, it is desirable to use a polyol crosslinking agent that provides molded articles with excellent compression set properties at high temperatures and does not contain fluorine atoms.

[0034] The fluororubber crosslinking composition of the present invention contains compounds having the structure described later as crosslinking agents. These compounds are easy to handle because they do not contain fluorine atoms. Furthermore, molded articles obtained from the fluororubber crosslinking composition of the present invention exhibit excellent compression set characteristics and tensile strength at high temperatures; even when the molded article is exposed to high temperatures, the tensile strength does not easily change, and the heat resistance is also excellent.

[0035] The components of the fluororubber crosslinking composition of the present invention will be described below.

[0036] (a) Fluororubber capable of polyol crosslinking

[0037] The fluororubber used in this invention, capable of polyol crosslinking, is a fluororubber having sites capable of polyol crosslinking. In this invention, fluororubber refers to amorphous fluoropolymers. "Amorphous" means that the melting peak (ΔH) observed in differential scanning calorimetry (DSC) (heating temperature 20°C / min) or differential thermal analysis (DTA) (heating rate 20°C / min) of the fluoropolymer is less than 4.5 J / g. Fluororubber exhibits elastomeric properties through crosslinking. Elastomeric properties refer to the ability to stretch the polymer and maintain its original length when the force required to stretch the polymer is no longer applied.

[0038] Examples of sites capable of polyol crosslinking include those containing vinylidene fluoride (VdF) units. Among these, fluororubbers containing VdF units are preferred because they readily utilize the effects of the crosslinking agent (b). Examples of fluororubbers containing sites capable of polyol crosslinking include:

[0039] The vinylidene fluoride (VDF) based fluoroelastomer described in Japanese Patent Application Publication No. 2003-277563 is substantially without polar terminal groups.

[0040] The Japanese Patent Publication No. 2018-527449 discloses a vinylidene fluoride-based fluoroelastomer comprising repeating units derived from vinylidene fluoride (VDF) and at least one additional repeating unit derived from a (per)fluorinated monomer.

[0041] Japanese Patent Application Publication No. 7-316377 discloses a cured fluoroelastomer comprising 100 parts (phr) of less than 67% by weight of fluorine, 40 to 68% by weight of vinylidene fluoride (VDF) units and 20 to 50% by weight of hexafluoropropylene (HFP) units in an aggregate manner totaling 100; and optionally containing one or more comonomers having unsaturated ethylene.

[0042] Examples of fluororubbers that have sites capable of crosslinking with polyols include non-perfluororubbers and fluororubbers with a main chain containing -CH2- (methylene).

[0043] Examples of fluororubbers having sites capable of polyol crosslinking include VdF-based fluororubbers and rubbers with functional sites capable of polyol crosslinking, such as double bonds in the side chains and / or main chains. Examples of VdF-based fluororubbers include tetrafluoroethylene (TFE) / propylene / VdF-based fluororubbers, ethylene / hexafluoropropylene (HFP) / VdF-based fluororubbers, VdF / HFP-based fluororubbers, and VdF / TFE / HFP-based fluororubbers. These fluororubbers having sites capable of polyol crosslinking can be used individually or in any combination without compromising the effects of the present invention.

[0044] As a VdF-based fluororubber, the material shown in the following general formula (1) is preferred.

[0045] -(M 1 )-(M 2 )-(N 1 )-(1)

[0046] (where M is the structural unit) 1 For those derived from vinylidene fluoride (m 1 Structural unit M 2 It is derived from fluorinated olefinic monomers (m 2Structural unit, structural unit N 1 is derived from a monomer (m 1 ) and monomer (m 2 ) copolymerizable monomer (n 1 ).)

[0047] In the VdF-based fluororubber represented by the general formula (1), it preferably contains 30 mol% to 85 mol% of structural unit M 1 , 55 mol% to 15 mol% of structural unit M 2 , more preferably structural unit M 1 is 50 mol% to 80 mol%, and structural unit M 2 is 50 mol% to 20 mol%. Structural unit N 1 relative to structural unit M 1 and structural unit M 2 is preferably 0 to 20 mol% of the total amount.

[0048] As the fluorinated ethylenically unsaturated monomer (m 2 ), one or more than one monomer can be used. For example, TFE, chlorotrifluoroethylene (CTFE), trifluoroethylene, HFP, trifluoropropene, tetrafluoropropene, pentafluoropropene, trifluorobutene, tetrafluoroisobutene, perfluoro(alkyl vinyl ether) (PAVE), general formula (2):

[0049] CF2=CFO(Rf 1 O) q (Rf 2 O) r Rf 3 (2)

[0050] (In the formula, Rf 1 and Rf 2 are each independently a straight-chain or branched perfluoroalkylene group having 1 to 6 carbon atoms, and Rf 3 is a straight-chain or branched perfluoroalkyl group having 1 to 6 carbon atoms, and q and r are each independently an integer from 0 to 6 (where 0 < q + r ≤ 6)) of the fluorinated monomer, general formula (3):

[0051] CHX 11 =CX 12 Rf 4 (3)

[0052] (In the formula, one of X 11 and X 12 is H and the other is F, and Rf 4 is a straight-chain or branched fluorinated alkyl group having 1 to 12 carbon atoms) of the fluorinated monomer, fluorinated monomers such as vinyl fluoride, etc. Among these, TFE, HFP, and PAVE are preferred.

[0053] As a monomer (n 1 ), as long as it can interact with the monomer (m) 1 ) and monomers (m 2 Copolymerization can be achieved using any monomer, such as ethylene, propylene, alkyl vinyl ethers, monomers that provide crosslinking sites, diene compounds, etc. They can be used individually or in any combination.

[0054] As a monomer that provides such a crosslinking site, general formula (4) can be cited:

[0055] CY 1 2 = CY 1 -Rf 5 CHR 1 X 1 (4)

[0056] (where Y) 1 Independently a hydrogen atom, a fluorine atom, or -CH3, Rf 5 It is a fluoroalkylene, perfluoroalkylene, fluoropolyoxyalkylene, or perfluoropolyoxyalkylene, R 1 For hydrogen atoms or -CH3, X 1 Monomers containing iodine or bromine (e.g., iodine or bromine atoms), general formula (5):

[0057] CF2 = CFO(CF2CF(CF3)O) m (CF2) n -X 2 (5)

[0058] (In the formula, m is an integer from 0 to 5, n is an integer from 1 to 3, X) 2 Monomers represented by cyano, carboxyl, alkoxycarbonyl, bromine, and iodine atoms, and general formula (6):

[0059] CH2=CH(CF2) p I (6)

[0060] (Where p is an integer from 1 to 10) Examples of monomers include, for instance, perfluorinated monomers such as perfluorinated (6,6-dihydro-6-iodo-3-oxa-1-hexene) and perfluorinated (5-iodo-3-oxa-1-pentene) as described in Japanese Patent Application Publication No. 5-63482 and No. 7-316234, and CF2=CFOCF2 as described in Japanese Patent Application Publication No. 4-217936. Iodine-containing monomers such as CF2CH2I, iodine-containing monomers such as 4-iodo-3,3,4,4-tetrafluoro-1-butene as described in Japanese Patent Application Publication No. 61-55138, bromine-containing monomers as described in Japanese Patent Application Publication No. 4-505341, and cyano-containing, carboxyl-containing, and alkoxycarbonyl-containing monomers as described in Japanese Patent Application Publication Nos. 4-505345 and 5-500070, etc. These can be used individually or in any combination.

[0061] Alternatively, the diene compound described in Japanese Patent Application Publication No. 8-12726 may be used as the diene compound.

[0062] Specifically, preferred examples of VdF-based fluororubbers include VdF / HFP-based rubbers, VdF / HFP / TFE-based rubbers, VdF / TFE / PAVE-based fluororubbers, VdF / CTFE-based rubbers, and VdF / CTFE / TFE-based rubbers.

[0063] Among these, the fluororubber capable of polyol crosslinking is preferably a fluororubber composed of VdF and at least one other fluorinated monomer, particularly preferably at least one rubber selected from the group consisting of VdF / HFP fluororubber, VdF / TFE / HFP fluororubber and VdF / TFE / PAVE fluororubber, and more preferably at least one rubber selected from the group consisting of VdF / HFP fluororubber and VdF / TFE / HFP fluororubber.

[0064] The Mooney viscosity (ML1+10(121°C)) of fluororubber at 121°C is preferably 1 or more, more preferably 3 or more, further preferably 5 or more, and particularly preferably 10 or more. Additionally, it is preferably 200 or less, more preferably 170 or less, further preferably 150 or less, even more preferably 130 or less, and particularly preferably 100 or less. The Mooney viscosity is determined according to ASTM D1646-15 and JIS K6300-1:2013.

[0065] The preferred fluorine content of fluororubber is 50% to 75% by mass. More preferably, it is 60% to 73% by mass, and even more preferably, it is 63% to 72% by mass. The fluorine content is calculated from the composition ratio of the monomer units constituting the fluororubber.

[0066] The preferred glass transition temperature for fluororubber is -50℃ to 0℃. The glass transition temperature can be determined as follows: using a differential scanning calorimeter, a 10mg sample is heated at 20℃ / min to obtain a DSC curve. The temperature at the intersection of the extension of the baseline representing the second-order phase transition of the DSC curve and the tangent at the inflection point of the DSC curve is taken as the glass transition temperature.

[0067] The fluororubber described above can be manufactured using conventional methods.

[0068] (b) Crosslinking agent

[0069] The fluororubber crosslinking composition of the present invention contains a crosslinking agent. The crosslinking agent is at least one selected from the group consisting of a compound represented by the following general formula (b) and a salt of the above compound with an alkali metal, alkaline earth metal or onium compound.

[0070] [Chemistry 3]

[0071]

[0072] (In the formula, m and n independently represent integers from 1 to 3; the hydrogen atoms bonded to the four benzene rings can be replaced by any substituents (excluding hydroxyl, thioalkyl, amino, acid groups, halogen atoms and groups containing halogen atoms).)

[0073] The compound represented by general formula (b) comprises a fluorene ring, with at least one hydroxyl group bonded to each of the two benzene rings bonded at the 9-position of the fluorene ring. The number of hydroxyl groups bonded to the two benzene rings can be arbitrarily selected in the range of 2 to 6, and the position of the hydroxyl groups is not limited. m and n represent the number of hydroxyl groups bonded to the two benzene rings at the 9-position of the fluorene ring. m and n can be, for example, independently 1 or 2. In this case, for example, one of the two hydroxyl groups can be bonded to the para position of each of the two benzene rings, and four hydroxyl groups can be bonded to the meta and para positions of the two benzene rings, respectively. The above-mentioned m and n are preferably integers from 1 to 2, and more preferably 1. In addition, from the viewpoint of good crosslinking characteristics, tensile strength of the molded article, and compression set characteristics, it is preferable to have a hydroxyl group at the para position of the benzene ring.

[0074] In the hydrogen atoms bonded to the fluorene ring and the two benzene rings, the unsubstituted hydrogen atoms can be replaced by substituents other than hydroxyl, thioalkyl, amino, acid, halogen atoms, and groups containing halogen atoms, or they can remain unsubstituted. Examples of substituents include cyano groups and alkyl groups having 1 to 10 carbon atoms. Since the substituents are halogen atoms such as groups without fluorine atoms or containing fluorine atoms, the compound shown in general formula (b) does not contain fluorine atoms.

[0075] An acid group is a group having a hydrogen atom that can ionize as a proton. In this invention, an acid group also includes salt groups where the hydrogen atom is replaced by other atoms (e.g., alkali metal atoms). Examples of acid groups include oxyacid groups (groups having an atom with a hydroxyl group (-OH) bonded to an oxygen group (=O) and the hydroxyl group being able to release a proton). Typical examples of acid groups are carboxyl, sulfonyl, sulfinyl, phosphate, phosphonic acid, and their salt salt groups.

[0076] The crosslinking agent can be a salt of the compound of general formula (b) and an alkali metal, a salt of the compound of general formula (b) and an alkaline earth metal, or a salt of the compound of general formula (b) and an onium compound. Among these salts, a salt of the compound of general formula (b) and an onium compound is preferred. The aforementioned salt of the compound and onium compound is an onium salt composed of an anionic portion from the aforementioned compound and a cationic portion from the onium compound. By using an onium salt as the crosslinking agent (b), the onium salt not only acts as a crosslinking agent but also as a crosslinking accelerator.

[0077] The compound represented by formula (b), the salt of the compound represented by formula (b) with an alkali metal, the salt of the compound represented by formula (b) with an alkaline earth metal, or the salt of the compound represented by formula (b) with an onium compound may be used alone or in combination.

[0078] The compound of general formula (b) and its salt with an ononium compound are obtained as follows: The compound of general formula (b) is reacted in water or an organic solvent with an alkaline substance such as sodium hydroxide, or with metallic sodium in an organic solvent, followed by a further reaction with an ononium compound such as benzyltriphenylphosphine chloride. The water or organic solvent is then removed by distillation. Alternatively, the solution of the reaction products can be filtered as needed, or the reaction products can be washed with water or an organic solvent to remove byproducts such as sodium chloride.

[0079] As an alkali metal, Na or K are preferred. As an alkaline earth metal, Ca or Mg are preferred.

[0080] Examples of onium salts include ammonium salts, phosphonium salts, and sulfonium salts.

[0081] Examples of ononium compounds constituting ononium salts include ammonium compounds, phosphonium compounds, and sulfonium compounds. In this invention, the ononium compounds do not contain fluorine atoms.

[0082] As the ononium compound constituting the ononium salt, ammonium compounds and phosphorus compounds are preferred, phosphorus compounds are more preferred, quaternary phosphorus compounds are even more preferred, and benzyltriphenylphosphonium is particularly preferred. As the ammonium compound, quaternary ammonium compounds are preferred, and 8-benzyl-1,8-diazabicyclo[5,4,0]-7-undeceneonium and benzyldimethyloctadecylammonium are more preferred.

[0083] As a crosslinking agent, it is preferably selected from at least one of the following groups: a compound represented by the following formula (b1) and a salt of the above compound and an alkali metal, alkaline earth metal or onium compound.

[0084] [Chemistry 4]

[0085]

[0086] The crosslinking agent can be used in combination with other compounds. Examples of mixtures containing the crosslinking agent include, for instance, mixtures of a solid solution of the crosslinking agent and a crosslinking accelerator, and mixtures of the crosslinking agent and a compound that can dissolve it. As a mixture of the crosslinking agent and the crosslinking accelerator, a mixture of the compound of general formula (b) and a quaternary phosphonium salt is preferred, or a mixture of the compound of general formula (b) and a quaternary ammonium salt is preferred, a mixture of the compound of general formula (b) and a quaternary phosphonium salt is more preferred, and a mixture of the compound of general formula (b) and benzyltriphenylphosphine chloride is even more preferred.

[0087] As for the content of the crosslinking agent, since it can produce molded articles with better tensile strength and compression set characteristics at high temperature, it is preferably 0.5 mmol to 50 mmol, more preferably 1.0 mmol or more, further preferably 2.0 mmol or more, more preferably 40 mmol or less, further preferably 30 mmol or less, and particularly preferably 20 mmol or less, relative to 100 parts by weight of fluororubber capable of polyol crosslinking.

[0088] (c) Crosslinking accelerator

[0089] The fluororubber crosslinking composition of the present invention may further contain a crosslinking accelerator. When a crosslinking accelerator is used, the crosslinking reaction is promoted by facilitating the formation of intramolecular double bonds in the dehydrofluoric acid reaction of the fluororubber backbone. When using a compound of general formula (b) as a crosslinking agent, it is preferable to use the crosslinking accelerator together with the crosslinking agent. Even when using an onium salt as a crosslinking agent, the crosslinking accelerator can be used together with the crosslinking agent, but it is not necessarily required. The amount of the crosslinking accelerator can be appropriately adjusted according to the crosslinking conditions and the physical properties of the molded article. Increasing the amount of the crosslinking accelerator accelerates the crosslinking reaction or allows crosslinking to occur at a lower temperature, but tends to worsen the compression set properties. Conversely, decreasing the amount of the crosslinking accelerator slows down the crosslinking reaction, but tends to improve the compression set properties.

[0090] Onium salts are commonly used as crosslinking promoters for polyol crosslinking systems (except for salts of compounds represented by general formula (b) and onium compounds). There are no particular limitations on the onium compounds; examples 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.

[0091] There are no particular limitations on whether it is a quaternary ammonium salt; examples include 8-methyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, 8-methyl-1,8-diazabicyclo[5,4,0]-7-undecenium iodide, 8-methyl-1,8-diazabicyclo[5,4,0]-7-undecenium hydroxide, and 8-methyl-1,8-diazabicyclo[5,4,0]-7-decenium chloride. Monocarbenzene methyl sulfate, 8-ethyl-1,8-diazabicyclo[5,4,0]-7-undecenenium bromide, 8-propyl-1,8-diazabicyclo[5,4,0]-7-undecenenium bromide, 8-dodecyl-1,8-diazabicyclo[5,4,0]-7-undecenenium chloride, 8-dodecyl-1,8-diazabicyclo[5,4,0]-7-undecenenium hydroxide Compounds, 8-eicosyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, 8-tetracosyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, 8-benzyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride (hereinafter referred to as DBU-B), 8-benzyl-1,8-diazabicyclo[5,4,0]-7-decenium chloride Examples of suitable crosslinking agents include monocarbenium hydroxide, 8-phenylethyl-1,8-diazabicyclo[5,4,0]-7-undeceneium chloride, 8-(3-phenylpropyl)-1,8-diazabicyclo[5,4,0]-7-undeceneium chloride, benzyl dimethyl octadecyl ammonium chloride, tetrabutyl ammonium bromide, tetrabutyl ammonium chloride, benzyl tributyl ammonium chloride, benzyl triethyl ammonium chloride, tetrabutyl ammonium hydrogen sulfate, and tetrabutyl ammonium hydroxide. Among these, DBU-B or benzyl dimethyl octadecyl ammonium chloride is preferred based on crosslinking properties and the physical properties of the crosslinked compounds.

[0092] In addition, there are no particular limitations on the quaternary phosphorus salt, and examples such as tetrabutylphosphine chloride, benzyltriphenylphosphine chloride (hereinafter referred to as BTPPC), benzyltrimethylphosphine chloride, benzyltributylphosphine chloride, tributylallylphosphine chloride, tributyl-2-methoxypropylphosphine chloride, and benzylphenyl(dimethylamino)phosphine chloride are preferred from the aspects of crosslinking and physical properties of crosslinked products.

[0093] The content of the crosslinking accelerator is preferably 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, further preferably 0.1 to 3 parts by mass, and particularly preferably 0.1 to 2 parts by mass, relative to 100 parts by mass of the polyol-crosslinkable fluororubber, so that a molded article with an appropriate crosslinking reaction rate and superior compression set characteristics at high temperatures can be obtained. It should be noted that when the crosslinking agent is a salt of a compound of general formula (b) and an onium compound, the above-mentioned content of the crosslinking accelerator is the mass value of the cationic portion of the crosslinking agent (i.e., the cation from the onium compound).

[0094] (d) Acid acceptor

[0095] The fluororubber crosslinking composition of the present invention may further contain an acid acceptor. By containing an acid acceptor, the crosslinking reaction of the fluororubber crosslinking composition proceeds more smoothly, and the tensile strength and compression set characteristics at high temperatures are further improved.

[0096] Examples of acid acceptors include: metal oxides such as magnesium oxide, calcium oxide, and bismuth oxide; metal hydroxides such as calcium hydroxide; alkali metal silicates such as hydrotalcite and sodium metasilicate, as described in Japanese Patent Application Publication No. 2011-522921; and metal salts of weak acids as described in Japanese Patent Application Publication No. 2003-277563. Examples of metal salts of weak acids include carbonates, benzoates, oxalates, and phosphites of Ca, Sr, Ba, Na, and K.

[0097] As an acid acceptor, since it can produce molded articles with superior compression set properties at high temperatures, at least one of the following is preferred: free metal oxides, metal hydroxides, alkali metal silicates, metal salts of weak acids, and hydrotalcite. More preferably, sodium metasilicate hydrate, calcium hydroxide, magnesium oxide, bismuth oxide, and hydrotalcite are selected. Furthermore, when the obtained molded article requires good water resistance, acid resistance, or resistance to organic acid esters, including biodiesel engines, at least one of the following is preferred as an acid acceptor: free bismuth oxide and hydrotalcite.

[0098] In the composition for crosslinking fluororubber, the content of the acid acceptor is preferably 0.1 to 100 parts by weight, more preferably 1 to 50 parts by weight, further preferably 1 to 30 parts by weight, and particularly preferably 1 to 20 parts by weight, relative to 100 parts by weight of fluororubber capable of polyol crosslinking, so that a molded article with better tensile strength and compression set at high temperature can be obtained.

[0099] If the content of the acid acceptor increases, the resulting molded article tends to have reduced water resistance, acid resistance, and resistance to organic acid esters, including biodiesel engines. On the other hand, if the content of the acid acceptor decreases, the crosslinking rate decreases, and the mechanical properties tend to decrease due to the reduced crosslinking density. Therefore, the content of the acid acceptor can be selected according to the intended use of the resulting molded article. In addition, when the molded article contains an acid acceptor other than calcium hydroxide, by reducing the content of calcium hydroxide to 0 to 1.5 parts by mass and adjusting the content of the other acid acceptor to adjust the crosslinking density, a molded article with better compression set characteristics at high temperatures can be obtained.

[0100] (e) Other ingredients

[0101] The fluororubber crosslinking composition can be mixed with commonly used additives as needed, such as fillers (carbon black, bituminous coal, barium sulfate, diatomaceous earth, calcined clay, talc, wollastonite, carbon nanotubes, etc.), processing aids, colorants, stabilizers, tackifiers (benzofuran resin, benzofuran-indene resin, etc.), conductivity imparting agents, thermal conductivity imparting agents, surface non-adhesives, flexibility imparting agents, heat resistance improvers, flame retardants, foaming agents, antioxidants described in International Publication No. 2012 / 023485, and other additives. It can also be mixed with one or more commonly used crosslinking agents and crosslinking accelerators that are different from the above substances. Among these, hot-dip galvanized carbon black and furnace black are preferred as carbon black, and MT carbon black, FT carbon black, and SRF carbon black are more preferred. Blending carbon black with larger particle sizes, such as carbon black or FT carbon black, yields molded products with excellent compression set properties. Blending carbon black with finer particle sizes yields molded products with excellent strength and elongation. By blending different grades, a balance of these properties can be achieved.

[0102] The aforementioned processing aids include plasticizers and mold release agents, without particular limitation. They can be mixed with, for example, synthetic fatty acid esters, waxes containing natural fatty acid esters, aliphatic amines such as stearamine, fatty acid amides such as stearamide, aliphatic alcohols, synthetic waxes such as polyethylene wax, phosphate esters such as tricresyl phosphate, silicone-based processing aids, etc. When two or more are mixed in appropriate amounts as needed, the balance between mold release properties and the physical properties of the molded product may sometimes improve. The aforementioned processing aids can be mixed within a range that does not impair the effects of this invention.

[0103] The content of fillers such as carbon black is not particularly limited, but is preferably 0 to 300 parts by mass relative to 100 parts by mass of fluororubber capable of polyol crosslinking, more preferably 1 to 150 parts by mass, further preferably 2 to 100 parts by mass, and particularly preferably 2 to 75 parts by mass.

[0104] The content of processing aids such as waxes is preferably 0 to 10 parts by weight, more preferably 0 to 5 parts by weight, relative to 100 parts by weight of fluororubber capable of polyol crosslinking. If processing aids, plasticizers, and mold release agents are used, there is a tendency for the mechanical properties and sealing properties of the resulting molded article to decrease. Therefore, it is necessary to adjust these contents within the range allowed by the characteristics of the target molded article.

[0105] The fluororubber crosslinking composition may contain a dialkyl sulfone compound. By containing a dialkyl sulfone compound, the crosslinking efficiency of the fluororubber crosslinking composition is improved, the crosslinking speed is accelerated, or the compression set characteristics are further improved, and the flowability of the rubber preform is improved. Examples of dialkyl sulfone compounds include dimethyl sulfone, diethyl sulfone, dibutyl sulfone, methyl ethyl sulfone, diphenyl sulfone, and sulfolane. Among these, sulfolane is preferred from the viewpoints of crosslinking efficiency, compression set characteristics, and suitable boiling point. The content of the dialkyl sulfone compound relative to 100 parts by weight of fluororubber is preferably 0 to 10 parts by weight, more preferably 0 to 5 parts by weight, and particularly preferably 0 to 3 parts by weight. When the fluororubber crosslinking composition of the present invention contains a dialkyl sulfone compound, the lower limit of the content of the dialkyl sulfone compound can be, for example, 0.1 parts by weight or more relative to 100 parts by weight of fluororubber.

[0106] Because of the good balance between crosslinking speed, flowability of rubber blank during molding, mold release properties during molding, and mechanical properties of molded products, the above-mentioned dialkyl sulfone compounds and the above-mentioned processing aids can be mixed simultaneously.

[0107] The fluororubber crosslinking composition is obtained by mixing fluororubber (a), a crosslinking agent (b), a crosslinking accelerator (c), an acid acceptor (d), and other components (e) using a commonly used rubber mixing apparatus. The rubber mixing apparatus can be a roller, kneader, Banbury mixer, internal mixer, twin-screw extruder, etc.

[0108] In addition, in order to make the components uniformly dispersed in the rubber, the following method can be used: fluororubber (a), crosslinking agent (b) and crosslinking accelerator (c) are melted and mixed at a high temperature of 100°C to 200°C using a closed mixing device such as a kneader, and then acid acceptor (d), other components (e) are mixed at a lower temperature below the above temperature.

[0109] Furthermore, after mixing fluororubber (a), crosslinking agent (b), crosslinking accelerator (c), acid acceptor (d), and other components (e), and then allowing it to stand at room temperature for more than 12 hours before mixing again, the dispersibility can be further improved.

[0110] Molded Products

[0111] The molded article of the present invention can be obtained by crosslinking the fluororubber crosslinking composition. Alternatively, the molded article of the present invention can also be obtained by molding and crosslinking the fluororubber crosslinking composition. The fluororubber crosslinking composition can be molded using existing known methods. The molding and crosslinking methods and conditions can be within the range of known methods and conditions used in molding and crosslinking. The order of molding and crosslinking is not limited; crosslinking can be performed after molding, molding can be performed after crosslinking, or molding and crosslinking can be performed simultaneously.

[0112] Examples of molding methods include compression molding, injection molding, extrusion molding, and molding using a drum vulcanizing machine, but these are not limited to. Examples of crosslinking methods include steam crosslinking, heated crosslinking, and radiation crosslinking, with steam crosslinking and heated crosslinking being preferred. Specific crosslinking conditions are not limited; generally, a temperature range of 140°C to 250°C and a crosslinking time of 1 minute to 24 hours are appropriately determined based on the types of crosslinking agent (b), crosslinking accelerator (c), and acid acceptor (d).

[0113] Furthermore, by heating the obtained molded articles using an oven or similar means, mechanical properties such as tensile strength, heat resistance, and compression set at high temperatures can be improved. As non-limiting specific crosslinking conditions, the temperature range of 140°C to 300°C and the time range of 30 minutes to 72 hours can be appropriately determined based on the types of crosslinking agent (b), crosslinking accelerator (c), and acid acceptor (d).

[0114] The molded articles of this invention exhibit excellent heat resistance, oil resistance, chemical resistance, and flexibility, and consequently, excellent compression set at high temperatures. Therefore, the molded articles of this invention are commonly used in parts that slide in contact with other materials, encapsulate and seal other materials or substances, and serve as vibration damping and soundproofing components. They can be used in various fields such as the automotive, aerospace, and semiconductor industries. In particular, the excellent compression set at high temperatures of the molded articles of this invention makes them suitable for use as sealing materials.

[0115] Examples of fields in which these technologies are used include, for instance, semiconductors, automobiles, aircraft, aerospace and rockets, shipbuilding, chemicals (including chemical plants), pharmaceuticals, photographs (including developing machines), printing machinery (including printing equipment), coating equipment (including coating equipment), analytical instruments and meters (including analytical and physical chemical machinery), food equipment (including food factory equipment and household products), beverage and food manufacturing equipment, pharmaceutical manufacturing equipment, medical components, chemical drug delivery equipment, nuclear power plant equipment, steel processing equipment, general industry, electrical systems, fuel cells, electronic components, optical equipment components, space equipment components, petrochemical plant equipment, oil and gas exploration and extraction equipment components, oil refining, and oil transportation equipment components.

[0116] As molded products, examples include rings, 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 various other sealing materials or gaskets. As sealing materials, they can be used in applications requiring heat resistance, solvent resistance, chemical resistance, and non-adhesive properties.

[0117] In addition, it can also be used as pipes, hoses, rollers, various rubber rollers, flexible joints, rubber sheets, coatings, belts, shock absorbers, valves, valve seats, valve bodies, chemical-resistant coating materials, lamination materials, lining materials, etc.

[0118] The cross-sectional shape of the aforementioned ring, gasket, and sealing element can be various shapes, specifically, such as square, O-shaped, or collar, or irregular shapes such as D-shaped, L-shaped, T-shaped, V-shaped, X-shaped, and Y-shaped.

[0119] In the aforementioned semiconductor-related fields, these devices can be used in, for example, semiconductor manufacturing equipment, liquid crystal panel manufacturing equipment, plasma panel manufacturing equipment, plasma display panel manufacturing equipment, plasma-addressable liquid crystal panel manufacturing equipment, organic EL panel manufacturing equipment, field emission display panel manufacturing equipment, solar cell substrate manufacturing equipment, and semiconductor transport equipment. Examples of such equipment include, for instance, CVD equipment, gas control equipment such as semiconductor gas control equipment, dry etching equipment, wet etching equipment, plasma etching equipment, reactive ion etching equipment, reactive ion beam etching equipment, sputtering etching equipment, ion beam etching equipment, oxidation diffusion equipment, sputtering equipment, ashing equipment, plasma ashing equipment, cleaning equipment, ion implantation equipment, plasma CVD equipment, exhaust equipment, exposure equipment, polishing equipment, film formation equipment, dry etching and cleaning equipment, UV / O3 cleaning equipment, ion beam cleaning equipment, laser beam cleaning equipment, plasma cleaning equipment, gas etching and cleaning equipment, and extraction equipment. Cleaning equipment, Soxhlet extraction cleaning equipment, high temperature and high pressure extraction cleaning equipment, microwave extraction cleaning equipment, supercritical extraction cleaning equipment, cleaning equipment using hydrofluoric acid, hydrochloric acid, sulfuric acid, ozone water, etc., lithography machines, coating and developing equipment, CMP equipment, excimer laser exposure machines, reagent piping, gas piping, plasma treatment equipment for NF3 plasma treatment, O2 plasma treatment, fluorine plasma treatment, etc., heat treatment film formation equipment, wafer transfer equipment, wafer cleaning equipment, silicon wafer cleaning equipment, silicon wafer processing equipment, equipment used in LP-CVD processes, equipment used in lamp annealing processes, equipment used in reflow processes, etc.

[0120] Specific applications in the semiconductor field include various sealing materials such as gate valves, quartz windows, chambers, chamber covers, gates, bell jars, connectors, and O-rings or gaskets for pumps; various sealing materials, hoses, or tubes such as O-rings for resist developers or strippers; liners or coatings for resist developer tanks, stripper tanks, wafer cleaning solution tanks, and wet etching tanks; pump diaphragms; rollers for wafer transport; hoses for wafer cleaning solutions; sealing materials for cleanrooms and other cleanroom equipment, such as sealants; sealing materials for storage facilities for semiconductor manufacturing equipment or wafers; and reagent delivery diaphragms used in semiconductor manufacturing processes.

[0121] In the aforementioned automotive field, these components can be used in engine blocks, main motion systems, valve systems, lubrication and cooling systems, fuel systems, intake and exhaust systems, drive system transmission systems, chassis control systems, braking systems, or basic electrical components, control system electrical components, equipment electrical components, and other electrical components. It should be noted that the aforementioned automotive field also includes autonomous two-wheeled vehicles.

[0122] In the aforementioned engine body or its peripheral devices, molded products can be used in various sealing materials that require heat resistance, oil resistance, fuel oil resistance, resistance to engine cooling antifreeze, and vapor resistance. Examples of such sealing materials include gaskets, shaft seals, valve stem seals, and other seals; non-contact or contact seals such as self-tightening seals, piston rings, open annular gaskets, mechanical seals, and oil seals; bellows, diaphragms, hoses, pipes; wires; cushioning materials; shock absorbers; and various sealing materials used in AT devices.

[0123] Specific applications of the aforementioned fuel systems include: O-rings used in fuel injectors, cold-start injectors, quick connectors for fuel lines, quick connectors for transmitter flanges, fuel pumps, quick connectors for fuel tanks, gasoline mixing pumps, gasoline pumps, fuel line bodies, fuel line connectors, and injectors; seals used in exhalation system manifolds, fuel filters, pressure regulating valves, fuel filter canisters, fuel tank caps, fuel pumps, fuel tanks, fuel tank delivery units, fuel injection devices, high-pressure fuel pumps, fuel line connection systems, pump timing control valves, intake control valves, solenoid valve subassemblies, and fuel shut-off valves; fuel filter canister solenoid valve seals, on-board refueling vapor recovery system (ORVR) valve seals, fuel pump oil seals, fuel delivery seals, fuel tank tipper valve seals, packing seals, injector seals, filler cap seals, and filler cap valve seals; fuel hoses, fuel supply hoses, fuel return hoses, vapor hoses, exhaust (ventilation) hoses, refueling hoses, filler cap hoses, fuel tank hoses, and hoses inside the fuel tank (tank hoses); and vaporization... Hose such as control hoses, fuel inlet hoses, and fuel vent hoses for fuel pumps; gaskets used in fuel filters, fuel line connection systems, and flange gaskets used in carburetors; pipeline materials for vapor recovery lines, fuel feedstock delivery lines, and oil / gas ORVR lines; diaphragms used in fuel canisters, ORVRs, fuel pumps, fuel tank pressure sensors, gasoline pumps, carburetor sensors, combined air control (CAC) devices, pulsation dampers, diaphragms for fuel canisters, automatic valves, and pressure regulator diaphragms for fuel injection devices; fuel pumps... Valves, carburetor needle valves, tip-over check valves, and check valves; exhaust ports (vents), pipes used inside fuel tanks; fuel tank gaskets, carburetor accelerator pump piston gaskets; fuel delivery shock-absorbing components for fuel tanks; O-rings and diaphragms for controlling fuel pressure; accelerator pump cups; built-in fuel pump mounts; fuel injection gaskets; injector seals; carburetor needle valve cores; carburetor accelerator pump pistons; valve seats for combined air control (CAC) devices; fuel tank bodies; sealing components for solenoid valves, etc.

[0124] Specific applications of the aforementioned braking systems include diaphragms used in vacuum boosters, hydraulic brake hoses, air brake systems, and brake chambers of air brake systems; hoses used in brake hoses, brake oil hoses, and vacuum brake hoses; various sealing materials such as oil seals, O-rings, gaskets, and brake piston seals; atmospheric or vacuum valves for vacuum boosters and check valves for brake valves; piston cups (rubber sealing cups) for master cylinders and brake sealing cups; protective covers for master cylinders or vacuum boosters of hydraulic brake systems and wheel cylinders of hydraulic brake systems; and O-rings or grommets for anti-lock braking systems (ABS).

[0125] Specific applications of the aforementioned basic electrical components include insulation or sheathing for wires (electrical wiring), conduits for external electrical wiring components, and grommets for connectors.

[0126] As a specific application form in electrical components of control systems, examples include the coating materials of various sensor lines.

[0127] Specific applications of the aforementioned electrical components include O-rings, gaskets, cooler hoses, high-pressure air conditioning hoses, air conditioning hoses, gaskets for electronic throttle valve units, protective covers for direct ignition plugs, and diaphragms for power distributors in automotive air conditioning systems. They can also be used for bonding electrical components.

[0128] Specific applications in the aforementioned intake and exhaust systems include gaskets used in intake manifolds and exhaust manifolds; throttling gaskets for throttle valves; diaphragms used in EGR (Exhaust Gas Recirculation), BPT (Blow-Pulse Control), exhaust valves, turbo exhaust valves, actuators, turbine actuators for variable geometry turbines (VTG), exhaust purge valves, etc.; control hoses for EGR (Exhaust Gas Recirculation), emission control hoses, turbocharger oil hoses (supply), turbocharger oil hoses (return), turbo air hoses, internal cooler hoses, turbocharger hoses, hoses connecting turbocharged engines with internal coolers to compressors, exhaust hoses, intake hoses, turbine hoses, DPF (Diesel Particulate Filter) sensor hoses, etc.; air ducts or turbine air ducts; intake manifold gaskets; sealing materials for EGR, afterburner prevention valve seats for AB valves, turbine shaft seal devices (for turbochargers, etc.), rocker covers used in automobile engines, or sealing components used in grooved parts such as air intake manifolds, etc.

[0129] In addition, it can be used as a seal in exhaust gas control components, such as in vapor recovery tanks, catalytic converters, exhaust gas sensors, oxygen sensors, etc., or as a seal in the armature of the solenoid valve of vapor recovery and vapor tanks; and as a manifold gasket for intake systems, etc.

[0130] In addition, it can be used in diesel engine-related components as O-ring seals for direct injection injectors, rotary pump seals, control diaphragms, fuel hoses, EGR, starter pumps, and diaphragms for turbocharger compensators. It can also be used in urea SCR systems as O-rings, sealing materials, hoses, pipes, diaphragms, gasket materials, pipelines, or as the urea tank body and sealing materials for urea SCR systems.

[0131] Specific applications of the aforementioned transmission system include bearing seals, oil seals, O-rings, gaskets, torque converter hoses, etc. Other examples include transmission oil seals, automatic transmission fluid hoses, ATF hoses, O-rings, and gaskets.

[0132] It should be noted that transmission devices include: AT (automatic transmission), MT (manual transmission), CVT (continuously variable transmission), DCT (dual-clutch transmission), etc.

[0133] In addition, examples include oil seals, gaskets, O-rings, and sealing gaskets for manual or automatic transmissions, or oil seals, gaskets, O-rings, and sealing gaskets for continuously variable transmissions (belt or ring type), as well as sealing gaskets for ATF linear solenoid valves, oil hoses for manual transmissions, ATF hoses for automatic transmissions, and CVTF hoses for continuously variable transmissions (belt or ring type).

[0134] As specific applications in the control system, examples include power steering hoses and high-pressure power steering hoses.

[0135] Examples of gaskets used in the main body of a car engine include cylinder head gaskets, cylinder head cover gaskets, oil pan gaskets, general gaskets, O-rings, sealing gaskets, timing belt cover gaskets, control hoses, engine mount shock absorbers, control valve diaphragms, and camshaft oil seals.

[0136] In the main motion system of an automobile engine, it can be used for crankshaft seals, camshaft oil seals, and other shaft sealing devices.

[0137] In the valve actuation system of automobile engines, it can be used for valve stem oil seal devices of engine valves, valve seats of butterfly valves, etc.

[0138] In the lubrication and cooling system of automobile engines, oil cooler hoses, return hoses, sealing gaskets, water hoses around radiators, radiator seals, radiator gaskets, radiator O-rings, vacuum pump oil hoses for vacuum pumps, as well as radiator hoses, radiator water tanks, hydraulic diaphragms, fan connection seals, etc.

[0139] Thus, as a specific example used in the automotive field, examples include engine mount gaskets, oil pan gaskets, manifold gaskets, oxygen sensor seals, oxygen sensor bushings, and nitrogen oxide (NOx) gaskets. x Sensor seals, nitrogen oxides (NOx) xSensor bushings, seals for sulfur oxide sensors, seals for temperature sensors, temperature sensor bushings, seals for diesel engine particulate filter sensors, diesel engine particulate filter sensor bushings, injector O-rings, injector gaskets, O-rings or diaphragms for fuel pumps, gearbox seals, power piston gaskets, cylinder liner seals, valve stem seals, static valve stem seals, dynamic valve stem seals, front pump seals for automatic transmissions, rear axle pinion seals, universal joint washers, pinion seals for speedometers, piston cups for foot brakes, O-rings or oil seals for torque transmission devices, seals or bearing seals for exhaust gas re-combustion devices, hoses for re-combustion devices, carburetor sensors. Instrument diaphragms, shock-absorbing rubber (engine mounts, exhaust systems, muffler hangers, suspension bushings, center bearings, support rubber bumpers, etc.), suspension shock-absorbing rubber (support rod assemblies, bushings, etc.), drive system shock-absorbing rubber (dampers, etc.), fuel hoses, EGR hoses or tubing, dual-chamber parallel-acting carburetor tubing, carburetor needle valve core valve, carburetor flange gaskets, oil hoses, oil cooler hoses, ATF hoses, cylinder head gaskets, water pump seals, gearbox seals, needle valve plates, motorcycle reed valve springs, automotive engine oil seals, fuel hose nozzle seals, automotive air conditioning unit seals, engine internal cooler rubber hoses, fuel line connectors. Seals for systems, CAC valves, needle plates, engine wiring harnesses, fuel filler hoses, O-rings for automotive air conditioning units, intake gaskets, fuel tank materials, diaphragms for distributors, hoses, clutch hoses, PS hoses, AT hoses, vacuum booster hoses, heater hoses, air conditioning hoses, ventilation hoses, fuel filler caps, PS rack seals, rack and pinion guards, CVJ guards, ball joint dust covers, strut dust covers, weatherstripping, glass channels, center unit gaskets, body side seals, bumper rubber, door locks, instrument panel insulators, high-tension wires, flat belts, multi-V belts, synchronous toothed belts, toothed belts, V-belts, tires, wiper blades, diaphragms or plungers for LPG automotive regulators, and diaphragms for CNG automotive regulators. This includes valves, DME-compatible rubber components, self-tensioning diaphragms or protective covers, diaphragms or valves for idle speed control, actuators for automatic speed control, diaphragms for negative pressure pumps, check valves or plungers, diaphragms or O-rings for OPS, gasoline pressure relief valves, O-rings or washers for engine cylinder liners, O-rings or washers for wet cylinder liners, seals or washers for differential gears (gear oil seals or washers), seals or washers for power steering systems (PSF seals or washers), seals or washers for shock absorbers (SAF seals or washers), seals or washers for constant velocity joints, seals or washers for wheel bearings, coatings for metal washers, caliper seals, protective covers, wheel bearing seals, and bladders used in tire vulcanization molding, etc.

[0140] In the aforementioned fields of aircraft, aerospace and rockets, and ships, it can be used particularly for fuel systems and lubrication systems.

[0141] In the aforementioned aircraft field, it can be used as, for example, various sealing components for aircraft, various aircraft components for aircraft oil applications, jet engine valve stem seals, gaskets or O-rings, rotary shaft seals, gaskets for hydraulic equipment, firewall seals, fuel supply hoses, gaskets or O-rings, aircraft cables, oil seal devices or shaft seal devices, etc.

[0142] In the aforementioned aerospace and rocket fields, it can be used as lip seals, diaphragms, O-rings, or O-rings resistant to gas turbine engine oils, as well as anti-vibration pads for missile ground control, for example, spacecraft, jet engines, and missiles.

[0143] In addition, in the marine industry, it can be used as, for example, propeller drive shaft stern seals, diesel engine intake and exhaust valve stem seals, butterfly valve valve seals, butterfly valve seats and shaft seals, butterfly valve shaft seals, stern pipe seals, fuel hoses, gaskets, engine O-rings, marine cables, marine oil seal devices, and marine shaft seal devices.

[0144] In the chemical industry, such as chemical plants, and in the pharmaceutical industry, it can be used in processes requiring high chemical resistance, such as the manufacturing processes of pharmaceuticals, pesticides, coatings, resins, and other chemicals.

[0145] Specific applications in the aforementioned chemical and pharmaceutical fields include: chemical equipment, chemical pumps or flow meters, chemical piping, heat exchangers, pesticide sprayers, pesticide delivery pumps, gas piping, fuel cells, analytical instruments or physicochemical instruments (e.g., analytical instruments, metering columns, fittings, etc.), shrink joints in flue gas desulfurization units, seals used in nitric acid plants, power plant turbines, etc., seals used in medical sterilization processes, seals for electroplating solutions, seals for papermaking pulleys, and joint seals in wind tunnels; O-rings used in chemical equipment such as reactors and mixers, analytical instruments or metering instruments, chemical pumps, pump housings, valves, rotary gauges, etc., O-rings for mechanical seals, and O-rings for compressor seals; gaskets used in the tube joints of high-temperature vacuum dryers, gas chromatographs or pH meters, etc., and sulfuric acid manufacturing. Glass cooler gaskets for equipment; diaphragms used in diaphragm pumps, analytical instruments, or physicochemical instruments; gaskets used in analytical instruments and measuring instruments; bushings (metal clamps) used in analytical instruments or measuring instruments; valve seats; U-shaped sealing cups; linings used in chemical equipment, gasoline tanks, wind tunnels, etc., and corrosion-resistant linings for acid-resistant aluminum processing tanks; coatings for plating masking fixtures; valve components for analytical instruments or physicochemical instruments; expansion joints in flue gas desulfurization plants; acid-resistant hoses for concentrated sulfuric acid, etc.; chlorine gas delivery hoses; oil-resistant hoses; rainwater drainage hoses for benzene or toluene storage tanks; chemical-resistant tubing or medical tubing used in analytical instruments or physicochemical instruments; trichloroethylene-resistant rollers or dyeing rollers for fiber dyeing; suppositories for pharmaceuticals; medical rubber suppositories; reagent bottles, reagent containers, bags, and medicine containers; protective gear such as gloves or boots resistant to strong acids and solvents, etc.

[0146] In the aforementioned fields of photography (such as developing machines), printing (such as printing machinery), and coating (such as coating equipment), they can be used as rollers, belts, seals, valve components, etc., for dry copiers.

[0147] Specific applications in the aforementioned fields of photography, printing, and coating include: the surface layer of the transfer roller in a copier; the cleaning blade in a copier; the tape in a copier; rollers (such as fixing rollers, pressing rollers, and pressure rollers) and tapes used in OA equipment such as copiers, printers, and fax machines; rollers, roller blades, and tapes in PPC copiers; rollers in film developing machines and X-ray film developing machines; printing rollers, doctor blades, tubes, valve components, and tapes in printing machinery; ink tubes, rollers, and tapes in printers; coating rollers, doctor blades, tubes, and valve components in coating and painting equipment; developing rollers, gravure rollers, guide rollers, guide rollers in magnetic tape manufacturing coating production lines, gravure rollers in magnetic tape manufacturing coating production lines, and coating rollers, etc.

[0148] The aforementioned food equipment, including food factory equipment and household products, can be used in food manufacturing processes, food conveyors, or food storage containers.

[0149] Specific applications in the aforementioned food equipment field include: seals for plate heat exchangers, solenoid valve seals for vending machines, gaskets for cans and jars, sewage pipe gaskets, pressure cooker gaskets, water heater seals, gaskets for heat exchangers, diaphragms or gaskets for food processing equipment, and rubber materials for food processing machines (such as heat exchanger gaskets, diaphragms, O-rings, and various other seals, piping, hoses, sanitary gaskets, valve gaskets, and filling gaskets used as joints between the bottle opening and the filler during filling). Additionally, examples include gaskets, washers, pipes, diaphragms, hoses, and connector sleeves used in alcoholic beverages, cold drinks, filling devices, food sterilization equipment, brewing equipment, water heaters, and various automatic food vending machines.

[0150] In the aforementioned field of nuclear power plant equipment, it can be used for check valves, pressure reducing valves, and seals in uranium hexafluoride enrichment devices around nuclear reactors.

[0151] Specific applications in the aforementioned general industrial fields include: sealing materials for hydraulic equipment such as machine tools, construction machinery, and hydraulic machinery; seals or bearing seals for hydraulic and lubrication machinery; sealing materials used in spindles; seals used in windows of dry cleaning equipment; seals for particle cyclotron accelerators or (vacuum) valves; seals for proton accelerators; seals for automatic packaging machines; diaphragms for pumps used in air sulfur dioxide or chlorine analysis devices (pollution analyzers); linings for snake pumps; rollers or belts for printing presses; conveyor belts; extrusion rollers for pickling iron plates; cable for robots; solvent extrusion rollers for aluminum calendering pipelines; O-rings for couplers; acid-resistant buffer materials; dustproof seals or lip rubber for sliding parts of cutting machinery; gaskets for waste incineration machines containing moisture; friction materials; surface modifiers for metals or rubber; and coating materials. In addition, it can be used as gaskets or sealing materials for devices used in papermaking processes, sealants for filter units in cleanrooms, sealants for construction, protective coatings for concrete or cement, glass cloth infiltration materials, processing aids for polyolefins, molding modifiers for polyethylene, fuel containers for small generators or lawnmowers, and pre-coated metal obtained by applying a base coat to metal sheets. Furthermore, it can be infiltrated into fabrics and sintered for use as sheets and strips.

[0152] As a specific application in the aforementioned steel industry, examples include iron plate processing rollers in iron plate processing equipment.

[0153] Specific applications in the aforementioned electrical fields include insulating oil caps for Shinkansen bullet trains, ventilation seals for liquid-sealed transformers, transformer seals, oil well cable jackets, seals for ovens such as electric furnaces, window frame seals for microwave ovens, sealing materials used in bonding wedges and grooves in CRTs, sealing materials for halogen lamps, fixing agents for electrical components, sealing materials for the end treatment of sheathed heaters, and sealing materials used in the insulation and moisture-proofing treatment of electrical equipment lead terminals. Furthermore, it can be used as a coating material for oil-resistant and heat-resistant wires, high-heat-resistant wires, chemical-resistant wires, high-insulation wires, high-voltage transmission lines, cables, wires used in geothermal power generation devices, and wires used around automobile engines. It can also be used in oil seal devices or shaft seal devices for vehicle cables. Moreover, it can be used in electrical insulation materials (such as insulating materials for various electrical equipment, insulating tapes used in cable joints or ends, materials used in heat-shrinkable tubing), and materials for electrical and electronic equipment used in high-temperature atmospheres (such as lead wire materials for motors and wire materials around high-temperature furnaces). It can also be used as a sealing layer or protective film (backsheet) for solar cells.

[0154] In the aforementioned field of fuel cells, it can be used as a sealing material between electrodes and between electrodes and separators in solid polymer fuel cells, phosphate fuel cells, etc., as well as a sealing component or gasket, separator, etc. for piping of hydrogen, oxygen, generated water, etc.

[0155] In the aforementioned field of electronic components, it can be used as a raw material for heat dissipation materials, a raw material for electromagnetic wave shielding materials, and gaskets for computer hard disk drives (magnetic recording devices). In addition, it can also be used as a buffer rubber (collision brake) for hard disk drives, a binder for the electrode active material of nickel-metal hydride secondary batteries, a binder for the active material of lithium-ion batteries, a polymer electrolyte for lithium secondary batteries, a bonding agent for the positive electrode of alkaline batteries, a binder for EL elements (electroluminescent elements), a binder for the electrode active material of condensers, an encapsulant, a sealant, a quartz coating material for optical fibers, films or sheets such as optical fiber coating materials, CMOS electronic circuits, transistors, integrated circuits, organic transistors, light-emitting elements, actuators, memories, sensors, coils, capacitors, resistors and other electronic components, potting, coating or bonding seals for circuit boards, fixing agents for electronic components, modifiers for encapsulants such as epoxy resin, coating agents for printed circuit boards, modifiers for prepreg resins such as epoxy resin for printed circuit boards, anti-scattering materials for light bulbs, gaskets for computers, large computer cooling hoses, gaskets or O-rings for secondary batteries, especially lithium secondary batteries, sealing layers for covering one or both sides of the outer surface of organic EL structures, connectors, dampers, etc.

[0156] In the field of equipment for transporting chemical products, safety valves or loading valves can be used in trucks, trailers, tank trucks, ships, etc.

[0157] In the field of energy exploration and extraction equipment components for oil, gas, etc., various sealing materials used in the extraction of oil, natural gas, etc., and protective covers for electrical connectors used in oil wells, etc.

[0158] Specific applications of these components in the energy exploration and extraction equipment field include drill bit seals, pressure regulating diaphragms, seals for horizontal excavating motors (stators), stator bearing (shaft) seals, sealing materials used in blowout preventers (BOPs), sealing materials used in rotary blowout preventers (drill pipe scrapers), sealing materials or gas-liquid connectors used in MWD (Minefield Deployment) systems, logging tool seals (e.g., O-rings, seals, gaskets, gaskets, protective covers, etc.) used in logging equipment (logging devices), expansion packers or completion packers and the packer seals used in them, and seals or gaskets used in cement grouting devices. Seals used in perforators (perforation devices), seals used in mud pumps, gaskets or motor liners, underground listening device covers, U-shaped sealing cups, composite mounting sealing cups, rotary seals, laminated elastic bearings, flow control seals, sand control seals, safety valve seals, hydraulic fracturing equipment (fracturing gear) seals, linear packers or linear hangers seals or gaskets, wellhead seals or gaskets, choke valves or valve seals or gaskets, sealing materials for LWD (logging while drilling), diaphragms used in oil exploration / oil drilling applications (e.g., diaphragms for lubricating oil supply in oil drilling fluid pools), gate valves, electronic protective covers, sealing elements for perforation guns, etc.

[0159] In addition, it can be used as a sealant for joints in kitchens, bathrooms, and toilets; adhesive tape for outdoor tents; sealants for stamp materials; rubber hoses for gas heat pumps and Freon-resistant rubber hoses; films, linings, and weather-resistant covers for agriculture; and tanks made of laminated steel plates used in construction or home appliances.

[0160] In addition, it can also be used in articles that are bonded to metals such as aluminum. Examples of such applications include door seals, gate valves, swing valves, solenoid valve tips, as well as metal-rubber parts bonded to metal, such as piston seals or diaphragms and metal gaskets.

[0161] In addition, it can also be used in rubber parts, brake pads, brake blocks, etc. in bicycles.

[0162] In addition, molded products can be used with belts.

[0163] Examples of belts include: power transmission belts (including flat belts, V-belts, V-ribbed belts, toothed belts, etc.) and conveyor belts (transmission belts), such as: flat belts used in various high-temperature areas such as around engines of agricultural machinery, machine tools, and industrial machinery; conveyor belts used for conveying loose or granular materials such as coal, gravel, sand, ore, and wood chips in high-temperature environments; conveyor belts used in steel mills such as blast furnaces; conveyor belts used in precision equipment assembly plants, food factories, etc., where they are exposed to high-temperature environments; V-belts or V-ribbed belts used in agricultural machinery, general equipment (such as OA equipment, printing machinery, business dryers, etc.), and automobiles; drive belts for conveying robots; toothed belts such as drive belts for food machinery and machine tools; and toothed belts used in automobiles, OA equipment, medical equipment, printing machinery, etc.

[0164] In particular, synchronous toothed belts are a representative example of toothed belts used in automobiles.

[0165] The aforementioned strip can be a single-layer structure or a multi-layer structure.

[0166] In the case of a multilayer structure, the above-mentioned strip may be composed of layers obtained by crosslinking a fluororubber crosslinking composition and layers formed of other materials.

[0167] In multi-layered belts, layers formed of other materials can include layers formed of other rubbers or thermoplastic resins, various fiber-reinforced layers, canvas, metal foil layers, etc.

[0168] Molded products can also be used in industrial vibration damping pads, vibration damping mats, railway flat steel billet pads (slab mats), pads, and automotive vibration damping rubber, etc. Examples of automotive vibration damping rubber include those for engine mounts, electric motor assembly, component assembly, support rod assembly, bushings, dampers, muffler hangers, and center bearings.

[0169] Other applications include connecting components such as flexible joints and expansion joints, protective covers, and cable rings. In the marine industry, examples include marine pumps.

[0170] Connection components refer to joints used in piping and piping equipment, which can be used for the following purposes: preventing vibration and noise generated by the piping system; absorbing expansion or displacement caused by temperature and pressure changes; absorbing dimensional changes; mitigating and preventing the effects of earthquakes and foundation settlement; etc.

[0171] Flexible joints and expansion joints are preferred for use in complex-shaped products such as shipbuilding piping, mechanical piping for pumps or compressors, chemical equipment piping, electrical piping, civil / waterway piping, and automotive piping.

[0172] Protective covers are preferred for use as complex-shaped molded products such as constant velocity universal joint protective covers, dust covers, rack and pinion control protective covers, bolt protective covers, piston protective covers, etc. for automobiles, agricultural machinery, industrial vehicles, construction machinery, hydraulic machinery, air compressor machinery, centralized lubrication machines, liquid transportation, fire fighting, and various liquefied gas transportation.

[0173] The molded products can also be used for diaphragms in filter presses, blowers, water supply systems, liquid storage tanks, pressure switches, accumulators, and air springs for hangers, etc.

[0174] By adding a molded product to rubber or resin, an antislip agent can be obtained, which can result in a molded product or coating that is less prone to slipping in environments wetted by water such as rain, snow, ice, or sweat.

[0175] In addition, molded products can also be used as cushioning materials for hot pressing during the manufacture of decorative plywood, printed circuit boards, electrical insulation boards, rigid PVC laminates, etc., using melamine resin, phenolic resin, epoxy resin, etc.

[0176] Molded products also help prevent seepage in various supports such as weapon-related sealing gaskets and protective clothing that protects against contact with aggressive chemical reagents.

[0177] In addition, it can be used for sealing and encapsulating various sealing materials such as O-rings, V-rings, X-rings, gaskets, washers, diaphragms, oil seals, bearing seals, lip seals, plunger seals, door seals, lip and end face seals, gas delivery plate seals, wafer support seals, and roller seals used in automobiles, ships, and other transportation equipment containing amine additives (especially amine additives used as antioxidants and cleaning dispersants). It can also be used as a material for lamination and lining. Furthermore, it can be used for sealing and encapsulating various sealing materials containing amine additives (especially amine additives used as antioxidants and cleaning dispersants) in automobiles, ships, and other transportation equipment.

[0178] It can also be used as a heat-resistant and oil-resistant wire coating material in the lead wires of sensors that detect the oil temperature and / or oil pressure of internal combustion engines such as automobiles, and in high-temperature oil atmospheres such as the oil pan of automatic transmissions or engines.

[0179] In addition, sometimes a vulcanized coating is formed on the molded product for use. Specifically, examples include non-adhesive oil-resistant rollers for copiers, weatherproof and anti-icing weatherstripping, rubber plugs for infusion, rubber plugs for small medicine bottles, anti-adhesive agents, non-adhesive lightweight conveyor belts, anti-adhesive coatings for flat washers of automobile engine mounts, coating processing of synthetic fibers, and bolt parts or joints with a thin layer of sealing gasket coating.

[0180] It should be noted that the application of molded products in automotive-related parts also includes applications in parts for motorized two-wheeled vehicles with the same structure.

[0181] In addition, fuels associated with the aforementioned automobiles include light oil, gasoline, and fuels for diesel engines (including biodiesel fuel).

[0182] Molded parts can also be used for seals in rolling bearings.

[0183] Examples of rolling bearings mentioned above include ball bearings, roller bearings, bearing units, and linear bearings.

[0184] Examples of ball bearings include radial ball bearings, thrust ball bearings, and thrust radial ball bearings.

[0185] Examples of radial ball bearings include deep groove ball bearings, radial ball bearings, four-point contact ball bearings, and self-aligning ball bearings.

[0186] The aforementioned deep groove ball bearings are used in applications such as electric motors, household appliances, and office automation (OA) equipment.

[0187] The aforementioned radial ball bearings can be categorized into single-row radial ball bearings, combined radial ball bearings, and multi-row radial ball bearings. Single-row radial ball bearings are used in electric motors, household appliances, office automation (OA) equipment, and hydraulic pumps and vertical pumps that apply axial loads in addition to radial loads. Combined radial ball bearings are used in machine tool spindles and grinding shafts where increased shaft rotational accuracy or rigidity is required. Multi-row radial ball bearings are used in automotive air conditioning electromagnetic clutches, etc.

[0188] The aforementioned four-point contact ball bearings are used in reducers and other applications where axial loads are applied from two directions and where a large bearing width space cannot be obtained.

[0189] The aforementioned self-aligning ball bearings are used in locations where self-alignment between the shaft and housing is difficult, or in drive shafts where the shaft is prone to bending.

[0190] The aforementioned thrust ball bearings include single-direction thrust ball bearings and multi-direction thrust ball bearings, and can be used for existing known applications of using these ball bearings.

[0191] The aforementioned thrust radial ball bearing is used in combination with multi-row cylindrical roller bearings as an axial load support for machine tool spindles.

[0192] Examples of roller bearings mentioned above include radial roller bearings and thrust roller bearings.

[0193] Examples of radial roller bearings mentioned above include cylindrical roller bearings, pin roller bearings, tapered roller bearings, and self-aligning roller bearings.

[0194] The aforementioned cylindrical roller bearings are used in general machinery, machine tools, electric motors, reducers, railway axles, aircraft, etc.

[0195] Needle roller bearings are used in general machinery, automobiles, electric motors, etc.

[0196] Tapered roller bearings are used in machine tools, automotive and railway axles, rolling mills, speed reducers, etc.

[0197] Self-aligning roller bearings are used in general machinery, rolling mills, papermaking machinery, axles, etc.

[0198] Examples of thrust roller bearings include thrust cylindrical roller bearings, thrust needle roller bearings, thrust tapered roller bearings, and thrust self-aligning roller bearings.

[0199] Thrust cylindrical roller bearings are used in machine tools, general machinery, etc.

[0200] Thrust needle roller bearings are used in automobiles, pumps, general machinery, etc.

[0201] Thrust tapered roller bearings are used in general machinery, rolling mills, etc.

[0202] Thrust self-aligning roller bearings are used in cranes, extruders, general machinery, etc.

[0203] In addition to being used as molded articles for crosslinking, fluororubber crosslinking compositions can also be used as various components in various industrial fields. Therefore, the applications of fluororubber crosslinking compositions will be described next.

[0204] Fluororubber crosslinking compositions can be used for surface modification materials of metals, rubbers, plastics, glass, etc.; sealing materials and coating materials requiring heat resistance, chemical resistance, oil resistance, and non-adhesiveness, such as metal gaskets and oil seal devices; non-adhesive coating materials such as rollers and belts for OA equipment, or exudation barriers; and coatings on woven fabric sheets and belts using infiltration and sintering.

[0205] Fluororubber crosslinking compositions, by virtue of their high viscosity and high concentration, can be used as sealing materials, linings, and sealants for complex shapes using conventional methods; by virtue of their low viscosity, they can be used to form films of several micrometers; and by virtue of their medium viscosity, they can be used for coating pre-coated metals, O-rings, diaphragms, and reed valves.

[0206] In addition, it can also be used for coating conveyor rollers or belts for woven fabrics or paper, printing belts, chemical-resistant tubes, suppositories, fuel hoses, etc.

[0207] As a substrate for articles coated with a fluororubber crosslinking composition, metals such as iron, stainless steel, copper, aluminum, and brass can be used; glass products such as glass plates, woven and nonwoven fabrics of glass fiber; molded articles and coatings of general-purpose and heat-resistant resins such as polypropylene, polyoxymethylene, polyimide, polyamide-imide, polysulfone, polyethersulfone, and polyetheretherketone; molded articles and coatings of general-purpose rubbers such as SBR, butyl rubber, NBR, and EPDM, as well as heat-resistant rubbers such as silicone rubber and fluororubber; woven and nonwoven fabrics of natural and synthetic fibers; and so on.

[0208] Coatings formed from fluororubber crosslinking compositions can be used in applications requiring heat resistance, solvent resistance, lubricity, and non-adhesiveness. Specific applications include rollers (e.g., fuser rollers, crimping rollers) and conveyor belts for OA equipment such as copiers, printers, and fax machines; sheets and belts; O-rings, diaphragms, chemical-resistant tubing, fuel hoses, valve seals, gaskets for chemical equipment, and engine gaskets.

[0209] The fluororubber crosslinking composition can also be dissolved in solvents and used as a coating or adhesive. Alternatively, it can be formulated into an emulsion dispersion (emulsion) for use as a coating.

[0210] Fluororubber crosslinking compositions are used as sealing materials or linings for various devices and piping, and as surface treatment agents for structures formed from inorganic and organic substrates such as metals, ceramics, glass, stone, concrete, plastics, rubber, wood, paper, and fibers.

[0211] Fluororubber crosslinking compositions can be applied to substrates by dispensing or screen printing.

[0212] The fluororubber crosslinking composition can also be used as a coating composition for casting films or for impregnating substrates such as fabrics, plastics, metals or elastomers.

[0213] In particular, the fluororubber crosslinking composition can be used in the form of an emulsion to manufacture covered fabrics, protective gloves, infiltrated fibers, O-ring covers, covers for fuel system quick-connect O-rings, covers for fuel system seals, covers for fuel tank tilt valve diaphragms, covers for fuel tank pressure sensor diaphragms, covers for oil filter and fuel filter seals, covers for fuel tank transmitter seals and transmitter head assembly seals, covers for copier fuser rollers, and polymer coating compositions.

[0214] They are useful in coatings of silicone rubber, nitrile rubber, and other elastomers. They are also useful in coatings of components made from such elastomers, to improve both the base elastomer's permeability and chemical resistance, in addition to its thermal stability. Other applications include heat exchangers, expansion joints, urns, tanks, blowers, flues, and other piping, as well as coatings for housing structures, such as concrete housing structures. Fluororubber crosslinking compositions can be applied, for example, to exposed sections of multilayer component structures in manufacturing methods of hose structures and diaphragms. Sealing components in joints and connections are often formed of rigid materials, and fluororubber crosslinking compositions can provide improved dimensional interference fits accompanied by reduced microleakage along the improved frictional interface and sealing surface. Their emulsions can improve the durability of seals in various automotive system applications.

[0215] They can also be used in the manufacture of power steering systems, fuel systems, air conditioning systems, and any joints where hoses and pipes connect to other components. A further useful application of fluororubber crosslinking compositions is the repair of manufacturing defects (and damage caused by use) in multi-layer rubber structures such as three-layer fuel hoses. Fluororubber crosslinking compositions can be formed before or after coating, or are useful for coating thin steel sheets that can be embossed. For example, multiple layers of coated steel can be assembled to form a gasket between two rigid metal components. A sealing effect can be achieved by applying the fluororubber crosslinking composition between its layers. In this process, it can be used to manufacture base gaskets and exhaust manifold gaskets to reduce bolt forces and strain in the assembled components, and to provide good fuel savings and low emissions through low cracking, flexing, and pore strain.

[0216] The fluororubber crosslinking composition can also be used as a coating agent; integral gaskets and sealing pads formed by dispensing on substrates containing inorganic materials such as metals and ceramics; and multilayers formed by coating on substrates containing inorganic materials such as metals and ceramics.

[0217] Fluororubber crosslinking compositions are also suitable as wiring materials for lightweight and flexible electronic devices, and can be used in known electronic components. Examples include CMOS electronic circuits, transistors, integrated circuits, organic transistors, light-emitting elements, actuators, memories, sensors, coils, capacitors, resistors, and other electronic components. By using these fluororubber crosslinking compositions, flexible electronic devices such as solar cells, various displays, sensors, actuators, electronic artificial skin, sheet-fed scanners, Braille displays, and wireless power transmission sheets can be obtained.

[0218] The embodiments have been described above, but it is understood that various changes can be made to the methods and details without departing from the spirit and scope of the claims.

[0219] Example

[0220] Next, embodiments will be given to illustrate the implementation of the present invention, but the present invention is not limited to the embodiments described.

[0221] The values ​​in the examples were measured using the following methods.

[0222] <Monomer Composition of Fluororubber>

[0223] use 19 The measurements were performed using F-NMR (Bruker AC300P model).

[0224] Fluorine content

[0225] By utilization 19 The composition of fluororubber, determined by F-NMR, was calculated.

[0226] Mooney viscosity

[0227] The measurements were performed according to ASTM D1646-15 and JIS K6300-1:2013. The measurement temperature was 121℃.

[0228] Glass transition temperature (Tg)

[0229] Using a differential scanning calorimeter (DSC822e manufactured by Mettler Toredo or X-DSC7000 manufactured by Hitachi High-Tech Science), a 10 mg sample was heated at 20 °C / min to obtain a DSC curve. The temperature at which the extended line representing the second-order phase transition of the DSC curve intersects the tangent at the inflection point of the DSC curve is taken as the glass transition temperature.

[0230] <Heat of Melting>

[0231] Using a differential scanning calorimeter (DSC822e manufactured by Mettler Toredo or X-DSC7000 manufactured by Hitachi High-Tech Science), a 10 mg sample was heated at 20 °C / min to obtain a DSC curve. The heat of fusion was calculated from the magnitude of the melting peak (ΔH) that appeared in the DSC curve.

[0232] <Acid Value>

[0233] Use 0.01 mol / L potassium hydroxide ethanol solution instead of 0.1 mol / L potassium hydroxide ethanol solution; otherwise, perform the determination according to the potentiometric titration method of JIS K0070.

[0234] <Crosslinking characteristics (maximum torque (MH), optimum crosslinking time (T90))>

[0235] For the composition for crosslinking fluororubber, a vulcanization testing machine (MDRH2030 manufactured by M&K Co., Ltd.) was used for the primary crosslinking, and the crosslinking curve was obtained at the temperatures shown in Table 1. The maximum torque (MH) and the optimum crosslinking time (T90) were determined from the change in torque.

[0236] <M100, tensile strength, and elongation at break>

[0237] Using a crosslinked sheet with a thickness of 2 mm, a test piece in the shape of dumbbell No. 6 was produced. Using the obtained test piece and a tensile testing machine (Tensilon RTG-1310 manufactured by A&D Co., Ltd.), the 100% modulus (M100), tensile strength, and elongation at break at 23°C were measured under the condition of 500 mm / min in accordance with JIS K6251:2010.

[0238] <Hardness>

[0239] Three crosslinked sheets with a thickness of 2 mm were overlapped, and the durometer hardness (Type A, peak value, value after 3 seconds) was measured in accordance with JIS K6251-3:2012.

[0240] <Heat aging test>

[0241] Using a crosslinked sheet with a thickness of 2 mm, a test piece in the shape of dumbbell No. 6 was produced. After heat-treating the obtained test piece at 275°C for 72 hours, the tensile strength of the heat-treated test piece was measured by the above method. Then, for the tensile strength, the change rate of the measured values before and after the heat treatment was calculated according to the following formula.

[0242] ΔX = (X - X0) / X0 × 100

[0243] ΔX: Change rate (%)

[0244] X0: Measured value before heat treatment

[0245] X: Measured value after heat treatment

[0246] <Compression set>

[0247] Using a small test piece for measuring compression set, the measurement was carried out under the conditions of a compression ratio of 25%, a test temperature of 200°C, and a test time of 72 hours in accordance with Method A of JIS K6262:2013.

[0248] The following materials were used in the examples and comparative examples.

[0249] Fluororubber A:

[0250] Molar ratio of vinylidene fluoride / hexafluoropropylene: 78 / 22

[0251] Fluorine content: 66%

[0252] Mooney viscosity (ML1+10 (121℃)): 43

[0253] Glass transition temperature: -18℃

[0254] Heat of fusion: Not confirmed in the second round

[0255] Acid value: 0.15 KOH mg / g

[0256] Fluororubber B:

[0257] Molar ratio of vinylidene fluoride / hexafluoropropylene: 78 / 22

[0258] Fluorine content: 66%

[0259] Mooney viscosity (ML1+10 (121℃)): 98

[0260] Glass transition temperature: -18℃

[0261] Heat of fusion: Not confirmed in the second round

[0262] Acid value: 0.56 KOH mg / g

[0263] MT carbon (N2SA: 8m) 2 / g, DBP: 43ml / 100g)

[0264] calcium hydroxide

[0265] magnesium oxide

[0266] Crosslinking accelerator: A mixture of 91% by mass benzyl dimethyl octadecyl ammonium chloride and 9% by mass isopropanol. Crosslinking agent-A: 9,9-bis(4-hydroxyphenyl)fluorene

[0267] Crosslinking agent-B: hydroquinone

[0268] Crosslinking agent - C: 2-methylresorcinol

[0269] Crosslinking agent-D: Bisphenol A

[0270] Crosslinking agent - E: 4,4'-dihydroxydiphenyl ether

[0271] Crosslinking agent-F: bis(4-hydroxyphenyl)sulfone

[0272] Crosslinking agent-G: 4,4'-dihydroxybenzophenone

[0273] Examples 1-2 and Comparative Examples 1-6

[0274] The components were mixed according to the formula in Table 1 and kneaded on a two-roll mill to prepare a fluororubber crosslinking composition. The maximum torque (MH) and optimal crosslinking time (T90) of the obtained fluororubber crosslinking composition are shown in Table 1. Next, the fluororubber crosslinking composition was crosslinked under the conditions described in Table 1 (compression crosslinking) and a second crosslinking at 230°C for 24 hours (heat crosslinking) to obtain crosslinked sheets (2 mm thick) and small test pieces for compression set testing. The evaluation results of the obtained crosslinked sheets and the results of the compression set test are shown in Table 1.

[0275] [Table 1]

[0276]

[0277] As shown in Table 1, the same fluororubber was used in Examples 1 and Comparative Examples 1-6. However, compared with Comparative Examples 1-6, which used conventional crosslinking agents, the molding articles obtained in Example 1, which used the compound represented by general formula (b) as a crosslinking agent, exhibited lower compression set, higher tensile strength, and a smaller rate of change in tensile strength after the heat aging test. Therefore, it can be seen that by using the fluororubber crosslinking composition of the present invention, molding articles with excellent compression set characteristics, tensile strength, and heat resistance at high temperatures can be obtained.

Claims

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

2. The composition for crosslinking fluororubber as described in claim 1, wherein, Fluororubber (a) contains vinylidene fluoride units.

3. The composition for crosslinking fluororubber as described in claim 1 or 2, wherein, The content of crosslinking agent (b) is 0.5 mmol to 50 mmol per 100 parts by weight of fluororubber (a).

4. The fluororubber crosslinking composition according to claim 1 or 2, further comprising a crosslinking accelerator (c).

5. The fluororubber crosslinking composition according to claim 1 or 2, further comprising an acid acceptor (d).

6. The composition for crosslinking fluororubber as described in claim 1 or 2, wherein, Relative to 100 parts by weight of fluororubber (a), it also contains 0.1 to 50 parts by weight of acid acceptor (d).

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

8. The composition for crosslinking fluororubber as described in claim 1 or 2, wherein, The crosslinking agent (b) is at least one selected from the group consisting of a compound represented by formula (b1) below, and a salt of said compound and an alkali metal, alkaline earth metal, or onium compound. [Chemistry 6] 。 9. A molded article obtained from any one of the fluororubber crosslinking compositions according to claims 1 to 8.

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

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