Uncrosslinked rubber composition for sealing materials and sealing materials manufactured using the same

Abstract

The present invention provides an uncrosslinked rubber composition for sealing materials that yields a sealing material with excellent low-temperature resistance. [Solution] The uncrosslinked rubber composition for sealing materials contains ethylene-butene-diene rubber, MAF carbon black, and a crosslinking agent. The ethylene-butene-diene rubber has an ethylene content of 35% to 65% by mass and a diene content of 3% to 12% by mass. The MAF carbon black content is 80 to 120 parts by mass per 100 parts by mass of ethylene-butene-diene rubber.

Description

[Technical Field]

[0001] This invention relates to an uncrosslinked rubber composition for sealing materials and a sealing material manufactured using the same. [Background technology]

[0002] It is known that sealing materials can be formed from a wide variety of rubber compositions. For example, Patent Document 1 discloses the formation of sealing materials from butyl rubber, fluororubber, and hydrogenated nitrile rubber compositions. Patent Document 2 discloses the formation of sealing materials for high-pressure gases from a silicone rubber composition. Patent Documents 3 and 4 disclose the formation of sealing materials for preventing carbon dioxide leakage from an ethylene-propylene rubber composition. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2003-28302 [Patent Document 2] International Publication No. 2007 / 145313 [Patent Document 3] Japanese Patent Publication No. 2002-212361 [Patent Document 4] Japanese Patent Publication No. 2015-206002 [Overview of the project] [Problems that the invention aims to solve]

[0004] Incidentally, sealing materials for high-pressure hydrogen equipment are required to maintain good sealing performance over a wide temperature range of -60°C to 120°C, and there is a particularly high demand for their ability to be used at low temperatures.

[0005] The object of the present invention is to provide an uncrosslinked rubber composition for sealing materials that can be obtained as a sealing material with excellent low-temperature resistance. [Means for solving the problem]

[0006] The present invention relates to an uncrosslinked rubber composition for sealing materials containing ethylene-butene-diene rubber, MAF carbon black, and a crosslinking agent, wherein the ethylene-butene-diene rubber has an ethylene content of 35% by mass or more and 65% by mass or less, and a diene content of 3% by mass or more and 12% by mass or less, and the content of the MAF carbon black is 80 parts by mass or more and 120 parts by mass or less per 100 parts by mass of the ethylene-butene-diene rubber.

[0007] The present invention relates to a sealing material formed from a rubber composition obtained by crosslinking the uncrosslinked rubber composition for sealing materials of the present invention. [Effects of the Invention]

[0008] According to the present invention, the uncrosslinked rubber composition for sealing materials contains ethylene-butene-diene rubber, MAF carbon black, and a crosslinking agent, wherein the ethylene-butene-diene rubber has an ethylene content of 35% to 65% by mass and a diene content of 3% to 12% by mass, and the MAF carbon black content is 80 to 120 parts by mass per 100 parts by mass of ethylene-butene-diene rubber. As a result, a sealing material formed from this crosslinked rubber composition can be obtained, which exhibits excellent low-temperature resistance. [Modes for carrying out the invention]

[0009] The embodiments will be described in detail below.

[0010] The uncrosslinked rubber composition for sealing materials according to the embodiment contains ethylene-butene-diene rubber (hereinafter referred to as "EBT"), MAF carbon black, and a crosslinking agent. The EBT has an ethylene content of 35% to 65% by mass and a diene content of 3% to 12% by mass. The MAF carbon black content is 80 to 120 parts by mass per 100 parts by mass of EBT.

[0011] According to the embodiment of the uncrosslinked rubber composition for sealing materials, the rubber composition contains EBT, MAF carbon black, and a crosslinking agent, wherein the EBT has an ethylene content of 35% to 65% by mass and a diene content of 3% to 12% by mass, and the MAF carbon black content is 80 to 120 parts by mass per 100 parts by mass of EBT. As shown in the examples described later, a sealing material formed from this crosslinked rubber composition can be obtained, which exhibits excellent low-temperature resistance.

[0012] EBT is a ternary copolymer of ethylene, 1-butene, and a non-conjugated diene component. Examples of non-conjugated diene components include 5-ethylidene-2-nobornene (ENB), 5-vinyl-2-nobornene (VNB), dicyclopentadiene, 1,4-hexadiene, and metallocene. The non-conjugated diene component preferably contains one or more of these, and from the viewpoint of obtaining excellent low-temperature resistance of the sealing material, it is preferable to include ENB and metallocene, and more preferably to include ENB.

[0013] The ethylene content of EBT is 35% by mass or more and 65% by mass or less, but from the viewpoint of obtaining excellent low-temperature resistance of the sealing material, it is preferably 40% by mass or more and 60% by mass or less, and more preferably 45% by mass or more and 55% by mass or less.

[0014] The diene content of EBT (or ENB content in the case of ENB) is 3% by mass or more and 12% by mass or less, but from the viewpoint of obtaining excellent low-temperature resistance of the sealing material, it is preferably 6% by mass or more and 10% by mass or less, and more preferably 7.5% by mass or more and 8.5% by mass or less.

[0015] From the viewpoint of obtaining excellent low-temperature resistance of the sealing material, the Mooney viscosity of EBT at 100°C is preferably 20ML(1+4)100°C or more and 100ML(1+4)100°C or less, more preferably 25ML(1+4)100°C or more and 75ML(1+4)100°C or less. The Mooney viscosity is measured in accordance with JIS K6300-1:2013.

[0016] The unvulcanized rubber composition for a sealing material may contain less rubber components other than EBT, such as ethylene-propylene-diene rubber (EPDM), ethylene-propylene rubber (EPR), nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), etc., than EBT.

[0017] MAF carbon black is a carbon black positioned in the middle between hard carbon blacks such as SAF carbon black, which are relatively hard and have a small particle size, and soft carbon blacks such as FEF carbon black, which are relatively soft and have a large particle size.

[0018] The arithmetic mean particle diameter (primary particle diameter) of MAF carbon black is preferably 30 nm or more and 40 nm or less. The arithmetic mean particle diameter (primary particle diameter) of MAF carbon black is obtained by observing MAF carbon black with a transmission electron microscope, randomly selecting 1000 particles, measuring their respective particle diameters, and calculating their arithmetic mean.

[0019] The nitrogen adsorption specific surface area (BET specific surface area) of MAF carbon black is preferably 40 m 2 / g or more and 60 m 2 / g or less. The nitrogen adsorption specific surface area (BET specific surface area) of MAF carbon black is measured based on JIS K6217-2:2017.

[0020] The DBP oil absorption of MAF carbon black is preferably 120 cm 3 / 100 g or more and 150 cm 3 / 100 g or less. The DBP oil absorption of MAF carbon black is measured based on JIS K6217-4:2017.

[0021] The iodine adsorption amount of MAF carbon black is preferably 50 mg / g or more and 70 mg / g or less. The iodine adsorption amount of MAF carbon black is measured based on JIS K6217-1:2017.

[0022] The content of MAF carbon black in the uncrosslinked rubber composition for sealing materials is 80 parts by mass or more and 120 parts by mass or less per 100 parts by mass of EBT, but from the viewpoint of obtaining excellent low-temperature resistance of the sealing material, it is preferably 90 parts by mass or more and 110 parts by mass or less, and more preferably 95 parts by mass or more and 105 parts by mass or less.

[0023] The uncrosslinked rubber composition for sealing materials may contain carbon black other than MAF carbon black in a smaller amount than MAF carbon black.

[0024] Examples of crosslinking agents include organic peroxides and sulfur. The crosslinking agent preferably contains organic peroxides and / or sulfur, and from the viewpoint of obtaining excellent low-temperature resistance of the sealing material, it is preferable that it contains organic peroxides.

[0025] Examples of organic peroxides include o-methylbenzoyl peroxide, bis(3,5,5-trimethylhexanoyl) peroxide, lauroyl peroxide, benzoyl peroxide, t-butyl peroxypivalate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxyisobutyrate, dicumyl peroxide, 1,3-bis(t-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-di(t-butylperoxy)-hexyne-3, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, and di-t-butyl peroxide. The organic peroxide preferably contains one or more of these, and from the viewpoint of obtaining excellent low-temperature resistance of the sealing material, it is preferable to contain one or more of 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 1,3-bis(t-butylperoxyisopropyl)benzene, and dicumyl peroxide, and more preferably to contain 2,5-dimethyl-2,5-di(t-butylperoxy)hexane.

[0026] From the viewpoint of obtaining excellent low-temperature resistance of the sealing material, the crosslinking agent content in the uncrosslinked rubber composition for sealing materials is preferably 0.5 parts by mass or more and 10 parts by mass or less, more preferably 1 part by mass or more and 5 parts by mass or less, per 100 parts by mass of EBT.

[0027] The uncrosslinked rubber composition for sealing materials according to the embodiment preferably further contains a crosslinking aid from the viewpoint of obtaining excellent low-temperature resistance of the sealing material.

[0028] Examples of crosslinking aids include polyfunctional unsaturated compounds. Specific examples of polyfunctional unsaturated compounds include quinone dioxime-based polyfunctional unsaturated compounds, methacrylate-based polyfunctional unsaturated compounds, allyl-based polyfunctional unsaturated compounds, and maleimide-based polyfunctional unsaturated compounds. Examples of quinone dioxime-based polyfunctional unsaturated compounds include p-quinone dioxime. Examples of methacrylate-based polyfunctional unsaturated compounds include triethylene glycol dimethacrylate, methyl methacrylate, and trimethylolpropane trimethacrylate. Examples of allyl-based polyfunctional unsaturated compounds include diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, and triallyl trimellitate. Examples of maleimide-based polyfunctional unsaturated compounds include maleimide, phenyl maleimide, and N,N'-m-phenylenebismaleimide. Other examples of polyfunctional unsaturated compounds include maleic anhydride, divinylbenzene, vinyltoluene, and 1,2-polybutadiene. The crosslinking aid preferably contains one or more of these, and from the viewpoint of obtaining excellent low-temperature resistance of the sealing material, it is preferable to contain a methacrylate-based polyfunctional unsaturated compound and / or an allyl-based polyfunctional unsaturated compound, more preferably trimethylolpropane trimethacrylate and / or triallyl isocyanurate, and even more preferably triallyl isocyanurate.

[0029] From the viewpoint of obtaining excellent low-temperature resistance of the sealant, the content of the crosslinking aid in the uncrosslinked rubber composition for sealing materials is preferably 0.1 parts by mass to 20 parts by mass, more preferably 1 part by mass to 5 parts by mass, per 100 parts by mass of EBT.

[0030] In an uncrosslinked rubber composition for sealing materials, the mass ratio of the crosslinking aid to the crosslinking agent is preferably 0.1 to 2, and more preferably 0.5 to 1.5, from the viewpoint of obtaining excellent low-temperature resistance of the sealing material.

[0031] The uncrosslinked rubber composition for sealing materials according to the embodiment preferably further contains a plasticizer from the viewpoint of obtaining excellent low-temperature resistance of the sealing material.

[0032] Examples of plasticizers include phthalate-based plasticizers, adipic acid-based plasticizers, sebaciate-based plasticizers, trimellitic acid-based plasticizers, and polymer-type plasticizers. Examples of phthalate-based plasticizers include dioctyl phthalate. Examples of adipic acid-based plasticizers include dioctyl adipate. Examples of sebaciate-based plasticizers include dioctyl sebaciate. Examples of trimellitic acid-based plasticizers include tri-(2-ethylhexyl) trimellitate. Examples of polymer-type plasticizers include polyether-based plasticizers and polyester-based plasticizers. The plasticizer preferably contains one or more of these, and from the viewpoint of obtaining excellent low-temperature resistance of the sealing material, it is more preferable to include a sebaciate-based plasticizer, and more preferable to include dioctyl sebaciate.

[0033] From the viewpoint of obtaining excellent low-temperature resistance of the sealing material, the plasticizer content in the uncrosslinked rubber composition for sealing materials is preferably 1 to 40 parts by mass, more preferably 8 to 12 parts by mass, per 100 parts by mass of EBT.

[0034] The uncrosslinked rubber composition for sealing materials according to the embodiment may also contain, as needed, an antioxidant, a processing aid, a metal oxide, a filler, a process oil, and the like.

[0035] Examples of antioxidants include amine-based antioxidants, phenol-based antioxidants, and imidazole-based antioxidants. Examples of processing aids include stearic acid, palmitic acid, and paraffin wax. Examples of metal oxides include zinc oxide, magnesium oxide, and calcium oxide. Examples of fillers include carbon black other than MAF carbon black, calcium carbonate, silica, barium sulfate, titanium dioxide, magnesium hydroxide, aluminum hydroxide, talc, clay, graphite, and calcium silicate. Examples of process oils include aromatic process oils, naphthenic process oils, and paraffinic process oils.

[0036] The uncrosslinked rubber composition for sealing materials according to this embodiment can be manufactured by putting EBT into a kneader and kneading it, then adding MAF carbon black, a crosslinking agent, and other compounding agents and mixing them together. Examples of kneaders include open roll, intermix, kneader, Banbury mixer, twin-screw extruder, etc.

[0037] The uncrosslinked rubber composition for sealing materials according to the embodiment can be molded into a predetermined sealing material shape and crosslinked to produce a sealing material made of the rubber composition. In this case, the crosslinking of the uncrosslinked rubber composition for sealing materials may be carried out in two stages: primary crosslinking (primary vulcanization) and subsequent secondary crosslinking (secondary vulcanization). Specifically, for example, using an injection molding machine, compression molding machine, press molding machine, etc., the uncrosslinked rubber composition for sealing materials can be molded into a predetermined sealing material shape using a mold, and primary crosslinking can be performed by heating it at a temperature of 120°C to 190°C and for a time of 1 minute to 30 minutes. After demolding the primary crosslinked product from the mold, secondary crosslinking can be performed by placing the demolded primary crosslinked product in an open oven and heating it at a temperature of 120°C to 200°C and for a time of 1 hour to 24 hours.

[0038] Incidentally, in recent years, the pressure of hydrogen handled by high-pressure hydrogen equipment has been increasing, but with sealing materials that have low pressure resistance, blistering such as cracks and foaming occurs on the surface when they come into contact with high-pressure hydrogen gas. In contrast, with a sealing material formed from a rubber composition in which the uncrosslinked rubber composition for sealing materials according to the embodiment has been crosslinked, blistering is suppressed even when it comes into contact with hydrogen gas at a high pressure of, for example, 35 MPa or higher, and good sealing performance is maintained, and in addition to excellent low-temperature resistance, excellent high-pressure resistance can also be obtained.

[0039] Based on the above, the sealing material produced from the uncrosslinked rubber composition for sealing materials according to the embodiment is suitable for high-pressure hydrogen equipment. Here, "high-pressure hydrogen equipment" refers to equipment that handles high-pressure hydrogen of 35 MPa to 105 MPa, and examples include valves, piping, and sensors for accumulators, as well as tanks and couplers that supply hydrogen to fuel cells in automobiles. The shape of the sealing material is not particularly limited and examples include shapes such as O-rings, gaskets, and sheets.

[0040] The hardness of the rubber composition forming the sealing material is preferably A80 to A95, more preferably A85 to A90. The hardness of the rubber composition is measured using a Type A durometer in accordance with JIS K6253-3:2012.

[0041] The tensile strength Tb at break of the rubber composition forming the sealing material is preferably 13 MPa or higher, more preferably 15 MPa or higher. The elongation Eb at break is preferably 50% or higher, more preferably 80% or higher. The 100% modulus S100 (tensile stress at 100% elongation) is preferably 10 MPa or higher and 25 MPa or lower, more preferably 15 MPa or higher and 20 MPa or lower. These tensile strength Tb at break, elongation Eb at break, and 100% modulus S100 are measured by a tensile test based on JIS K6251:2023.

[0042] The compression set CS of the rubber composition forming the sealant is preferably 20% or less. The compression set CS of the rubber composition is measured in accordance with JIS K6262:2013, at a test temperature of 150°C and a test time of 70 hours, and at a test temperature of 120°C and a test time of 70 hours.

[0043] The TR10 of the rubber composition forming the sealant is preferably -56°C or lower, more preferably -58°C or lower, and even more preferably -60°C or lower. The TR10 of the rubber composition is measured based on the TR test of JIS K6261-4:2017. [Examples]

[0044] (Uncrosslinked rubber composition for sealing materials) Uncrosslinked rubber compositions for sealing materials were prepared according to Examples 1-2 and Comparative Examples 1-6 below. Their respective compositions are also shown in Table 1.

[0045] <Example 1> EBT (K-9330M, manufactured by Mitsui Chemicals, non-conjugated diene component: ENB, ethylene content: 50% by mass, diene content (ENB content): 7.1% by mass, Mooney viscosity: 30ML(1+4)100℃) is added to an open roll and kneaded. Then, for every 100 parts by mass of EBT, MAF carbon black (Seas 116, manufactured by Tokai Carbon Co., Ltd., arithmetic mean particle size: 38nm, nitrogen adsorption specific surface area (BET specific surface area): 53m²) is added. 2 / g, DBP oil absorption: 133cm 3 An uncrosslinked rubber composition for sealing material was prepared by adding and kneading 100 parts by mass of (100g, iodine adsorption capacity: 53mg / g), 3 parts by mass of the crosslinking agent 2,5-dimethyl-2,5-di(t-butylperoxy)hexane (Perhexa 25B, manufactured by NOF Corporation), 3 parts by mass of the crosslinking aid trialyl isocyanurate (TAIC®, manufactured by Mitsubishi Chemical Corporation), 10 parts by mass of the plasticizer dioctyl sebacate (DOS), 1 part by mass of a quinoline-based antioxidant, 0.5 parts by mass of the processing aid stearic acid, and 5 parts by mass of the metal oxide zinc oxide, and this was designated as Example 1.

[0046] <Example 2> An uncrosslinked rubber composition for sealing material was prepared in the same manner as in Example 1, except that the amount of DOS plasticizer was 5 parts by mass per 100 parts by mass of EBT, and this was designated as Example 2.

[0047] <Comparative Example 1> A non-crosslinked rubber composition for sealing material was prepared in the same manner as in Example 1, except that EPDM (Esplen® 532, manufactured by Sumitomo Chemical Co., Ltd., non-conjugated diene component: ENB, ethylene content: 51% by mass, diene content (ENB content): 3.5% by mass, Mooney viscosity: 81ML(1+4)125℃) was used instead of EBT, the amounts of MAF carbon black and the plasticizer DOS were set to 120 parts by mass and 20 parts by mass, respectively, per 100 parts by mass of EPDM, and an amine-based antioxidant was added in addition to 1 part by mass per 100 parts by mass of EPDM. This was designated as Comparative Example 1.

[0048] <Comparative Example 2> A non-crosslinked rubber composition for sealing material was prepared in the same manner as in Example 1, except that EPDM was used instead of EBT, the amount of MAF carbon black was 90 parts by mass per 100 parts by mass of EPDM, and 1 part by mass of an amine-based antioxidant was added per 100 parts by mass of EPDM. This was designated as Comparative Example 2.

[0049] <Comparative Example 3> An uncrosslinked rubber composition for sealing material was prepared in the same manner as in Example 1, except that EPDM was used instead of EBT, and this was designated as Comparative Example 3.

[0050] <Comparative Example 4> EPDM is used instead of EBT, and FEF carbon black (Seast SO, manufactured by Tokai Carbon Co., Ltd.) is used instead of MAF carbon black. Arithmetic mean particle size: 43 nm, Nitrogen adsorption specific surface area (BET specific surface area): 42 m² 2 / g, DBP oil absorption: 115cm 3 An uncrosslinked rubber composition for sealing material was prepared in the same manner as in Example 1, except that it used (100g, iodine adsorption amount: 44mg / g), and this was designated as Comparative Example 4.

[0051] <Comparative Example 5> An unvulcanized rubber composition for a sealing material was prepared in the same manner as in Example 1, except that EPDM was used instead of EBT and the compounding amount of MAF carbon black was 130 parts by mass with respect to 100 parts by mass of EPDM, and this was designated as Comparative Example 5.

[0052] <Comparative Example 6> An unvulcanized rubber composition for a sealing material was prepared in the same manner as in Example 1, except that EPDM was used instead of EBT and HAF carbon black (manufactured by Tokai Carbon Co., Ltd., Seast 300, arithmetic average particle diameter: 28 nm, nitrogen adsorption specific surface area (BET specific surface area): 84 m 2 / g, DBP oil absorption: 75 cm 3 / 100g、iodine adsorption amount: 86 mg / g) was used instead of MAF carbon black, and this was designated as Comparative Example 6.

[0053]

Table 1

[0054] (Sealing material, rubber sheet for test piece, and test piece for compression set test) For each of the unvulcanized rubber compositions for a sealing material of Examples 1 to 2 and Comparative Examples 1 to 6, it was charged into a mold for molding a sealing material, set in a press molding machine, heated under the conditions of a temperature of 170 °C and a time of 20 minutes to perform primary crosslinking, and after the primary crosslinked product was demolded from the mold, the demolded primary crosslinked product was put into an oven and heated under the conditions of a temperature of 150 °C and a time of 4 hours to perform secondary crosslinking to produce a sealing material. Also, a rubber sheet for a test piece and a test piece for a compression set test were produced in the same manner.

[0055] (Test method and results) The following tests were conducted on the unvulcanized rubber compositions for a sealing material of Examples 1 to 2 and Comparative Examples 1 to 6, and the sealing materials, rubber sheets for test pieces, and test pieces for compression set tests produced by crosslinking them. The test results are shown in Table 2.

[0056] <Kneadability> The kneadability of each of the uncrosslinked rubber compositions for sealing materials in Examples 1-2 and Comparative Examples 1-6 was evaluated using an open roll according to the following criteria. A: The uncrosslinked rubber composition can be wrapped around the roll and kneaded smoothly, and the uncrosslinked rubber composition does not become sticky or develop holes during kneading. B: The uncrosslinked rubber composition does not wrap around the roll and cannot be kneaded, or the uncrosslinked rubber composition becomes sticky or develops holes during kneading.

[0057] <Moldability> For each of the uncrosslinked rubber compositions for sealing materials in Examples 1-2 and Comparative Examples 1-6, the fluidity of the uncrosslinked rubber composition during the molding of the primary crosslinked product using a press molding machine during the production of the sealing material, and the release properties when demolding the primary crosslinked product from the mold thereafter, were evaluated according to the following criteria. A: The uncrosslinked rubber composition has good fluidity, and the primary crosslinked material has good release properties, allowing the primary crosslinked material to be molded well. B: The uncrosslinked rubber composition has poor fluidity, or the primary crosslinked product has poor release properties, making it impossible to properly mold the primary crosslinked product.

[0058] <Hardness> Test specimens were prepared by crosslinking each of the uncrosslinked rubber compositions for sealing materials of Examples 1-2 and Comparative Examples 1-6. The rubber sheets were stacked to form test specimens, and their hardness was measured using a Type A durometer in accordance with JIS K6253-3:2012.

[0059] <Tensile properties> Test specimens were cut from rubber sheets prepared by crosslinking each of the uncrosslinked rubber compositions for sealing materials of Examples 1-2 and Comparative Examples 1-6, and based on JIS K6251:2023 Next, the tensile strength Tb at break, elongation Eb at break, and 100% modulus S100 (tensile stress at 100% elongation) were measured.

[0060] <Compression set (heat resistance)> For the test pieces for the compression set test prepared by crosslinking each of the uncrosslinked rubber compositions for sealing materials of Examples 1 to 2 and Comparative Examples 1 to 6, in accordance with JIS K6262:2013, the compression set CS was measured when the test temperature was 150 °C and the test time was 70 hours, and when the test temperature was 120 °C and the test time was 70 hours.

[0061] <TR10 (Low temperature resistance)> Test pieces were cut out from the rubber sheets for test pieces prepared by crosslinking each of the uncrosslinked rubber compositions for sealing materials of Examples 1 to 2 and Comparative Examples 1 to 6, and TR10 was determined based on the TR test of JIS K6261-4:2017. Further, evaluation was made according to the following criteria. A: TR10 ≤ -56 °C B: TR10 > -56 °C

[0062] <Blister resistance (High pressure resistance)> The sealing materials prepared by crosslinking each of the uncrosslinked rubber compositions for sealing materials of Examples 1 to 2 and Comparative Examples 1 to 6 were stored in a pressure vessel filled with hydrogen gas at a pressure of 70 MPa for 168 hours, and then the presence or absence of blister formation on the surface of the sealing material was visually confirmed and evaluated according to the following criteria. A: No blisters B: Blisters present

[0063]

Table 2

Industrial applicability

[0064] The present invention is useful in the technical field of uncrosslinked rubber compositions for sealing materials and sealing materials manufactured using the same.

Claims

1. An uncrosslinked rubber composition for sealing materials containing ethylene-butene-diene rubber, MAF carbon black, and a crosslinking agent, The ethylene-butene-diene rubber has an ethylene content of 35% by mass or more and 65% by mass or less, and a diene content of 3% by mass or more and 12% by mass or less. An uncrosslinked rubber composition for sealing materials, wherein the MAF carbon black content is 80 parts by mass or more and 120 parts by mass or less per 100 parts by mass of the ethylene-butene-diene rubber.

2. In the uncrosslinked rubber composition for sealing material described in claim 1, An uncrosslinked rubber composition for sealing materials containing an organic peroxide as the crosslinking agent.

3. In the uncrosslinked rubber composition for sealing material described in claim 1, An uncrosslinked rubber composition for sealing materials, wherein the content of the crosslinking agent is 0.5 parts by mass or more and 10 parts by mass or less per 100 parts by mass of the ethylene-butene-diene rubber.

4. In the uncrosslinked rubber composition for sealing material described in claim 1, An uncrosslinked rubber composition for sealing materials further containing a crosslinking aid.

5. In the uncrosslinked rubber composition for sealing materials described in claim 4, An uncrosslinked rubber composition for sealing materials containing triallyl isocyanurate as the crosslinking aid.

6. In the uncrosslinked rubber composition for sealing materials described in claim 4, An uncrosslinked rubber composition for sealing materials, wherein the content of the crosslinking aid is 0.1 parts by mass or more and 20 parts by mass or less per 100 parts by mass of the ethylene-butene-diene rubber.

7. In the uncrosslinked rubber composition for sealing materials described in claim 4, An uncrosslinked rubber composition for sealing materials, wherein the mass ratio of the content of the crosslinking aid to the content of the crosslinking agent is 2 or less.

8. In the uncrosslinked rubber composition for sealing material described in claim 1, An uncrosslinked rubber composition for sealing materials further containing a plasticizer.

9. A sealing material formed from a rubber composition obtained by crosslinking an uncrosslinked rubber composition for sealing materials described in any one of claims 1 to 8.

10. In the sealing material described in claim 9, The aforementioned sealing material is a sealing material for use in high-pressure hydrogen equipment.

Images