KR20190086519A - Rubber compositions for use in sealing members for high-pressure gases, sealing members for high-pressure gases, devices for high-pressure gases and high-pressure gas-sealing methods - Google Patents

Abstract

A rubber composition for use in a sealing member for a high-pressure gas satisfying both excellent abrasion resistance, low temperature resistance, heat resistance and blister resistance, and a sealing member for high-pressure gas. A rubber composition for use in a sealing member for high-pressure gas sealing a high-pressure gas, wherein the rubber component in the rubber composition comprises polybutadiene and / or polystyrene butadiene rubber, and the rubber composition has a glass transition point ≪ / RTI >

Description

Rubber compositions for use in sealing members for high-pressure gases, sealing members for high-pressure gases, devices for high-pressure gases and high-pressure gas-sealing methods

The present invention relates to a rubber composition for use in a sealing member for a high-pressure gas, a sealing member for a high-pressure gas, and a high-pressure gas appliance having the sealing member. The present invention also relates to a method of sealing a high-pressure gas. And more particularly, to a rubber composition and a sealing member for use in a sealing member for a high-pressure gas sealing hydrogen or helium, and a high-pressure gas appliance having the sealing member. The present invention also relates to a method of sealing a high-pressure gas.

In recent years, energy-efficient fuel cells have become hot topics due to energy problems such as depletion of oil resources and global environmental problems. Fuel cells are systems that generate electricity by reacting hydrogen and oxygen, but there is a challenge in the handling of hydrogen.

At present, a method of storing hydrogen at a high pressure, a method of adsorbing and storing hydrogen by adsorbing the metal, and a method of removing hydrogen by modifying a hydrocarbon have been proposed. In the case of storing hydrogen at a high pressure, do.

In addition, a high-pressure tank of about 70 MPa is stored in a fuel cell vehicle (FCV). In the hydrogen station that supplies hydrogen to the FCV, compressed heat is generated at the time of charging. Therefore, hydrogen that has been cooled to -40 ° C as precooling is supplied to the FCV, and high-pressure hydrogen gas A sealing member for sealing is required. Although the metal seals are used in the present hydrogen station, the metal seals are inferior in the maintenance property. Thus, in part, a rubber composition is used as a sealing member as a substitute for a metal seal.

Generally, the functions required for the rubber composition for sealing a high-pressure gas include those that are not destroyed by pressurization and depressurization (that is, do not generate blisters), that retain rubber elasticity even when the temperature is extremely low at adiabatic expansion due to rapid decompression And so on. For example, in CNG (compressed natural gas, about 20 MPa) known as a high-pressure fuel gas, it is known that the temperature is lowered to about -60 DEG C due to adiabatic expansion in a sudden depression. Referring to this, it is considered that since the hydrogen gas is stored at a pressure equal to or higher than CNG, it is required to maintain rubber elasticity even at -60 캜 or lower. However, ethylene-propylene-diene rubber (EPDM), which is mainly used at present, has insufficient rubber elasticity only up to about -45 DEG C, and therefore, low temperature characteristics are not sufficient.

For this reason, research and development of high-pressure gas sealing members have been progressing, and butyl rubber, fluorine rubber, hydrogenated nitrile rubber, EPDM and the like have been proposed as rubber compositions for sealing members for high-pressure gas (see Patent Documents 1 to 3, Patent Document 1).

Patent Document 4 describes a silicone rubber having a specific structure as a rubber composition used as a sealing material for hydrogen gas.

On the other hand, polybutadiene rubber and polystyrene butadiene rubber are known as general purpose rubbers, and they are generally used for tire applications. In addition, polybutadiene rubber or polystyrene butadiene rubber is a rubber having relatively high gas permeability.

Japanese Patent Application Laid-Open No. 2003-28302 Japanese Patent Laid-Open Publication No. 2015-108104 Japanese Patent Application Laid-Open No. 2015-206002 International Publication No. 2008/001625

Japan Rubber Society: Vol. 89, No. 10, Page. 302-306 (2016)

However, the rubber compositions such as butyl rubber, fluorine rubber, hydrogenated nitrile rubber and EPDM disclosed in Patent Documents 1 to 3 are liable to be impaired in sealing property at low temperatures. For example, even if EPDM is used under an environment of -40 占 폚, temperature control becomes difficult, and there is a problem that leakage occurs immediately when the EPDM deviates downward to about -45 占 폚. The fluorine rubber has insufficient low-temperature characteristics and is difficult to seal under the environment of -40 ° C. In addition, at least butyl rubber, fluororubber and hydrogenated nitrile rubber are problematic in that blisters are generated during rapid pressure reduction.

In addition, the silicone rubber disclosed in Patent Document 4 has a problem that the sealing property is impaired at the sliding portion. For example, the sealing member used in the hydrogen station has many sliding parts, and it is difficult to use silicone rubber as such a member. In addition, cost reduction is naturally required when the number of used parts is expanded due to the spread of FCV, but the cost of the silicon rubber is limited because the material itself is expensive.

The sealing member for high-pressure gas is required to maintain the sealing property not only at a low temperature but also at a high temperature of about 100 DEG C, but the conventional rubber composition has insufficient sealing ability in a wide temperature range and has room for improvement.

As described above, there is a phenomenon that a sealing member which can be used at a sliding portion without damaging the sealing property even in a wide temperature range (particularly at a low temperature) is required.

On the other hand, as described above, in order to seal the high-pressure gas, various functions are required for the rubber composition, and special rubber such as butyl rubber, fluorine rubber, hydrogenated nitrile rubber, EPDM and silicone rubber has been conventionally used as a sealing member. Further, as a sealing member, a material having a low gas permeability tends to be used in order to enhance airtightness. Therefore, it has not been considered to use a polybutadiene rubber or a polystyrene butadiene rubber, which is a general rubber and has a relatively high gas permeability, as a sealing member for high-pressure gas.

However, the inventors of the present invention have found that, in order to maintain the sealability over a long period of use, it is necessary to improve the durability against wear rather than the gas-tightness at the time of gas storage and to suppress the breakage of the sealing member at the time of pressure change I found that it is important to

Under these circumstances, it is an object of the present invention to provide a rubber composition for use in a sealing member for a high-pressure gas satisfying both excellent abrasion resistance, low temperature resistance, heat resistance and blister resistance, and a sealing member for high-pressure gas.

It is another object of the present invention to provide a high-pressure gas appliance provided with a sealing member for a high-pressure gas.

It is another object of the present invention to provide a method for sealing a high-pressure gas.

The present inventors have focused on polybutadiene rubber or polystyrene butadiene rubber mainly used for tire use and have conducted intensive studies to solve the above problems. As a result, it has been found that polybutadiene rubber and polystyrene butadiene rubber have relatively high gas permeability, Surprisingly, the above problems can be solved, and the present invention has been accomplished.

That is, the present invention relates to the following invention.

<1> A rubber composition for use in a sealing member for a high-pressure gas which seals a high-pressure gas, wherein the rubber component in the rubber composition comprises polybutadiene rubber and / or polystyrene butadiene rubber, Of the total weight of the rubber composition.

<2> The rubber composition according to <1>, wherein the high-pressure gas is hydrogen or helium.

<3> The rubber composition according to <1> or <2>, wherein the high-pressure gas is a high-pressure gas of 1 MPa or more.

<4> The rubber composition according to any one of <1> to <3>, wherein the content of the structural unit derived from butadiene in the rubber component is 70% by mass or more with respect to the rubber component.

&Lt; 5 > The rubber composition according to any one of < 1 > to < 4 >, wherein the polybutadiene rubber is of a sheath type.

<6> The rubber composition according to any one of <1> to <5>, wherein the rubber composition is a peroxide vulcanization.

<7> The rubber composition according to any one of <1> to <5>, wherein the rubber composition is acetone as a solvent and the extraction amount of the extract when subjected to Soxhlet extraction based on Method A described in JIS K 6229 (2013) &Lt; 6 &gt;.

<8> A sealing member for a high-pressure gas formed by using the rubber composition according to any one of <1> to <7>.

<9> The sealing member for high-pressure gas according to <8>, wherein the sealing member for high-pressure gas is any one selected from the group consisting of an O-ring, a packing and a gasket.

<10> A high-pressure gas appliance comprising the sealing member for high-pressure gas according to <8> or <9>.

<11> The high-pressure gas appliance according to the above <10>, wherein the high-pressure gas appliance is a high-pressure gas vessel or a high-pressure gas piping appliance.

<12> The method according to <10> or <11>, wherein the high-pressure gas device is any one selected from the group consisting of a high-pressure hydrogen container, a high-pressure helium container, a pipe device for high-pressure hydrogen, device.

<13> The method according to any one of <10> to <12>, wherein the high-pressure gas device is any one selected from the group consisting of a tank, an accumulator, a valve, a joint, a coupler, a safety valve, a check valve, A high pressure gas appliance as claimed.

<14> The high-pressure gas appliance according to any one of <10> to <13>, wherein the high-pressure gas appliance has a pressure resistance of 1 MPa or more.

A method of sealing a high-pressure gas of a high-pressure gas appliance using a sealing member, wherein the sealing member is molded using a rubber composition, wherein the rubber component in the rubber composition is a polybutadiene rubber and / or a polystyrene- Wherein the rubber composition is a rubber composition having a glass transition point of not higher than -65 占 폚.

<16> The method according to the above <15>, wherein the high-pressure gas is hydrogen or helium.

<17> The method according to <15> or <16>, wherein the high-pressure gas is a high-pressure gas of 1 MPa or more.

According to the present invention, it is possible to provide a rubber composition and a sealing member for a high-pressure gas for use in a sealing member for a high-pressure gas satisfying both excellent abrasion resistance, low temperature resistance, heat resistance and blister resistance.

It is also possible to provide a high-pressure gas appliance provided with a sealing member for high-pressure gas.

Further, it is possible to provide a sealing method of high-pressure gas.

1 is a schematic view of a section of a pressure proof test apparatus used in the hydrogen pressure cycle test of the embodiment.
2 is a photograph of a device for internal pressure test before attaching a jig having a gas supply port and a leak detecting part.
3 is a schematic view of a section of a pressure resistance test apparatus before attaching a jig having a gas supply port and a leak detection zone.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, the present invention will be described in detail by showing examples and the like, but the present invention is not limited to the following examples and the like, and can be arbitrarily changed without departing from the gist of the present invention. In the present application, when the expression &quot; ~ &quot; is used, the term &quot; ~ &quot;

1. Rubber composition of the present invention

The present invention relates to a rubber composition for use in a sealing member for high-pressure gas sealing a high-pressure gas, wherein the rubber component in the rubber composition comprises polybutadiene rubber and / or polystyrene butadiene rubber, (Hereinafter sometimes referred to as &quot; the rubber composition of the present invention &quot;).

In the present invention, the "rubber component" is a component comprising a rubber component contained in the rubber composition of the present invention, and is a component excluding a compounding agent such as a filler from the rubber composition of the present invention. In the rubber composition of the present invention, the rubber type constituting the rubber component includes polybutadiene rubber and / or polystyrene butadiene rubber. The rubber composition of the present invention may be composed solely of a rubber component or may be composed of a compounding agent such as a filler in addition to the rubber component. The details will be described later.

In the present invention, the term "glass transition point" means a glass transition point determined by DSC measurement (differential scanning calorimetry) at a heating rate of 20 ° C / min based on JIS K 6240 (2013). In DSC measurement, it is necessary to carry out temperature calibration by the reference material (cyclohexane) described in Annex JB of JIS K 6240 (2013) and adjustment of the baseline described in JIS K 7122 (2014) beforehand.

First, the rubber composition of the present invention is a rubber composition for use in a sealing member for high-pressure gas sealing a high-pressure gas.

Particularly, the rubber composition of the present invention is preferably used for a sealing member sealing hydrogen or helium.

Hydrogen or helium is a gas that is difficult to seal because its molecular size is smaller than other gases and it is easily permeable to substances. However, the rubber composition of the present invention has excellent sealing characteristics even for a gas having a small molecular size such as hydrogen or helium .

Further, the rubber composition of the present invention is preferably used for sealing a high-pressure gas of 1 MPa or more in a high-pressure gas, and particularly preferably used for sealing hydrogen or helium of 1 MPa or more.

The rubber composition of the present invention can maintain rubber elasticity even at a low temperature (for example, about -40 DEG C) or a high temperature (for example, about 85 DEG C), and is excellent in abrasion resistance and blister resistance, Even when used in sliding parts of devices used over a wide temperature range, it exhibits excellent sealing performance.

Although the rubber composition of the present invention has relatively high gas permeability, the details of the mechanism capable of sealing the high-pressure gas are unclear, but are presumed as follows.

In a sealing member for a high-pressure gas such as hydrogen or helium, there is known a blister breaker which is liable to occur at the time of rapid pressure reduction, protruding breakage accompanied by volume expansion, buckling breakage, This is a phenomenon that occurs because the dissolved gas is released at once during decompression. A low gas permeability coefficient of the rubber composition constituting the sealing member is high in airtightness, but it also takes a long time for high resistance to discharge of the gas dissolved in the sealing member, so that a large force is applied from the inside of the material for a long time, .

On the other hand, a high gas permeability coefficient of the rubber composition constituting the sealing member is such that a small force is only received from the inside of the sealing member for a short period of time since the gas is dissolved in the sealing member and discharged at a low resistance and in a short time. It becomes difficult to occur.

That is, since the polybutadiene rubber and the polystyrene-butadiene rubber have a high gas permeability coefficient, it is considered that the rubber composition of the present invention is hardly destroyed since the gas dissolved in the sealing member can be released with low resistance during a rapid depressurization .

Further, since the sealing member for high-pressure gas is usually disposed between the member and the member and is difficult to contact with the high-pressure gas, it is presumed that the gas could be sufficiently sealed even though the gas permeability was as high as that of polybutadiene rubber or polystyrene butadiene rubber.

Further, since the sealing member for high-pressure gas is usually disposed between the member and the member and hardly comes into contact with the atmosphere, even when the sealing member includes a rubber material having low weather resistance, ozone resistance and oil resistance such as polybutadiene rubber and polystyrene butadiene rubber It is presumed that the composition is hardly subject to deterioration. Particularly when the high-pressure gas is hydrogen, since hydrogen is a reducing gas, hydrogen is partially dissolved in the rubber, and oxidation deterioration represented by ozone resistance is hardly received.

As a result, it is presumed that the rubber composition of the present invention can simultaneously satisfy excellent abrasion resistance, low temperature resistance, heat resistance and blister resistance.

As described later in the Examples, it was found that the sealing lower limit temperature of the sealing member for high-pressure gas was 25 ° C to 30 ° C higher than the glass transition point of the rubber composition constituting the sealing member for high-pressure gas. Since the rubber composition of the present invention has a glass transition point of -65 캜 or lower, it can withstand the use environment of -40 캜 or lower. When the rubber composition of the present invention has a glass transition point of about -95 占 폚, it can be used even in a use environment of -70 占 폚.

Although the glass transition point can be adjusted according to the use environment as described above, it is preferably -80 DEG C or lower and -90 DEG C or lower in order to maintain excellent sealing performance even at a lower temperature.

Further, a plurality of glass transition points may be observed in the rubber composition of the present invention. The rubber composition of the present invention may have a glass transition point at a temperature higher than -65 占 폚 and at least two glass transition points at -65 占 폚 or less provided that the rubber composition has at least one glass transition point at -65 占 폚 or lower .

As described above, the rubber composition of the present invention comprises a rubber component alone or a compounding agent such as a rubber component and a filler.

Specifically, the content of the rubber component in the rubber composition of the present invention can be determined from the total organic component analyzed by the method described in JIS K 6226-2 (2013) Acetone) extraction amount.

The content of the rubber component in the rubber composition is not particularly limited, but is preferably 20 to 70% by mass, more preferably 20 to 66% by mass, more preferably 35 to 50% by mass when the rubber composition is 100% More preferably, it is in mass%.

The rubber component of the rubber composition of the present invention may contain a rubbery material of polybutadiene rubber and / or polybutadiene styrene rubber, and may be a polybutadiene rubber alone, a polybutadiene styrene rubber alone, a mixture of polybutadiene rubber and polybutadiene styrene rubber (Hereinafter sometimes referred to as &quot; other rubber types &quot;) other than polybutadiene rubber and polybutadiene styrene rubber insofar as the object of the present invention is not impaired.

Hereinafter, the polybutadiene rubber and the polybutadiene styrene rubber will be described in detail.

[Polybutadiene rubber]

Polybutadiene rubber (hereinafter sometimes referred to as &quot; BR &quot;) is a polymer obtained by 1,3-butadiene addition polymerization of conjugated diene monomer. That is, BR is a polymer comprising structural units derived from butadiene.

(Cis-1,4 bond (cis), trans-1,4 bond (trans), 1,2 bond (vinyl) by the bonding mode (monomer bonding style) of the structural unit derived from butadiene ) Is formed in the main chain, and the 1,2 bond has an asymmetric carbon atom, so that, when a chain of 1,2 bonds is generated, the absolute arrangement difference causes isotactic, syndiotactic, and atactic 3 Type stereoregularity (tacticity) is expressed. In general, the bonding mode in the polybutadiene main chain is called a microstructure, and these microstructures and stereoregularity can be controlled by selecting a polymerization method.

Regarding the microstructure of BR, the glass transition point (tg) shows a large width due to the 1,2-bond content (vinyl content) and moves toward the high temperature side when the vinyl content increases and toward the low temperature side when the vinyl content decreases . For example, if the vinyl content is about 80 mol%, tg is about -35 DEG C, and if the vinyl content is about 10 mol%, tg is about -90 DEG C.

BR is classified into a difference in microstructure and polymerization method and the like, but the kind of the polybutadiene rubber contained in the rubber composition of the present invention is not particularly limited as long as the object of the present invention is not impaired. From the viewpoint of low-temperature sealability of the sealing member, BR having a vinyl content of 50 mol% or less is preferable, and BR having a vinyl content of 40 mol% or less is more preferable. For example, as the BR having a 1,2-bond (vinyl) content of 50 mol% or less, there may be mentioned a gossy type polybutadiene rubber (Gossys-BR) and a sheath type polybutadiene rubber (low sheath- .

The gossy type polybutadiene rubber means a polybutadiene rubber having a cis-1,4 bond content (sheath content) of 90 mol% or more in the polybutadiene main chain, and the low sheath type polybutadiene rubber means a polyisobutylene rubber having a cis- Means a polybutadiene rubber having a content of 52 mol% or less.

The glass transition point (tg) of gossypic BR is about -100 to -95 ° C, which is excellent in low temperature characteristics. The cis-type has an advantage that crystallization of the cis-1,4 bond is hard to occur. Further, the discrimination between the gossy type and the low sheath type can also be made for a sealing member for a high-pressure gas after vulcanization and molding. It is possible to calculate the sheath content by NMR measurement using a sample excluding unnecessary matters such as oil by Soxhlet extraction, and it is possible to discriminate between the gossy type and the sheath type.

As the preferable polybutadiene rubber, there can be mentioned a hyposilicone type polybutadiene rubber. By using the sheath type polybutadiene rubber, the low-temperature characteristics and the abrasion resistance become better, and blistering is more difficult to occur. Further, the lower sheath type polybutadiene rubber has lower glass transition point and lower crystallization degree of cis-1,4 bond observed in GOSIS-BR is less likely to occur as the vinyl bond content is lower, The lower the content of the bond, the better.

Specific examples of the polybutadiene rubber include JSR BR01, JSR T700, JSR BR51 and JSR BR730 of JSR products, Nipol BR1220 of Nippon Zeon product, UBEPOL BR150, UBEPOL BR150B, UBEPOL BR130B, UBEPOL BR160L, UBEPOL BR360L, Nipol 1250H of Nippon Zeon product, Dien NF35R of Asahi Kasei product, Liquid polybutadiene LBR-300, LBR-302B, LBR of Kuraray Co., Ltd. can be used as the low sheath type polybutadiene rubber as BR230, UBEPOL BR710, UBEPOL BR133P, -305, LBR-307, LBR-352, and LBR-361 can be used.

[Polystyrene butadiene rubber]

Polybutadiene styrene rubber (hereinafter sometimes referred to as &quot; SBR &quot;) is a polymer in which 1,3-butadiene is styrene. That is, it is a polymer comprising a structural unit derived from butadiene and a structural unit derived from styrene.

In SBR, emulsion-polymerized SBR and solution-polymerized SBR are mainly industrialized, and as the SBR contained in the rubber composition of the present invention, solution-polymerized SBR having excellent low-temperature characteristics is preferable.

Specifically, as the polybutadiene styrene rubber, JSR 1500, JSR 1502, JSR 1507, JSR 0202, JSR 1503, etc. of JSR products can be used. As the solution polymerization SBR, Tufdene 1000, Tufdene 2000R of Asahi Kasei, JSR SL552, JSR SL563 of JSR, and Nipol NS116R of Nippon Zeon product can be used.

In the rubber composition of the present invention, as described above, the rubber component may include other rubber types, and may include polybutadiene rubber and / or polybutadiene styrene rubber and other rubber types (other than polybutadiene rubber and polybutadiene styrene rubber ) May be blended and used. The kind of the other rubber type is not particularly limited, and is appropriately selected according to the purpose.

Preferred examples of other rubber types include nitrile rubber (NBR), ethylene-propylene-diene rubber (EPDM), and silicone rubber

For example, a nitrile rubber (low nitrile NBR) having a low glass transition point may be blended to improve abrasion resistance. The nitrile rubber is not particularly limited. For example, JSR N260S of JSR product, Nipol DN401, Nipol DN401L and Nipol DN401LL of Nippon Zeon products can be used.

It is also possible to blend ethylene-propylene-diene rubber (EPDM) having a low glass transition point for improving weatherability, for example. EPDM is not particularly limited. For example, NORDEL IP4570, NORDEL IP5565 from Dow Chemical, Esprene 532, Esprene 7456 from Sumitomo Chemical Co., T7141 and EP342 from JSR can be used.

It is also possible to blend with silicone rubber to improve the low temperature characteristics. The silicone rubber is not particularly limited, and for example, KE-136Y-U and KE-186-U of Shin-Etsu Chemical Co., Ltd. and DY32-379U of Dow Corning products can be used.

Blending with fluorine rubber is also possible to further improve the high temperature properties. There is no particular limitation on the fluorine rubber, and examples thereof include Viton A type, B type, F type manufactured by DuPont Kabushiki Kaisha, Diel G700 series, 800 series and 900 series manufactured by Daikin Industries, Ltd., It is possible to use an Aplas 100 series, 150 series or the like manufactured by Kabushiki Kaisha.

In the case where the rubber component in the rubber composition of the present invention contains a mixture of polybutadiene rubber and polybutadiene styrene rubber or other rubber type, the amount of each rubber type to be blended is preferably within a range that can achieve the object of the present invention, As shown in FIG.

Preferably, the content of the structural unit derived from butadiene in the rubber component is 70 mass% or more with respect to the rubber component. If the content of the structural unit derived from butadiene in the rubber component is 70 mass% or more with respect to the rubber component, it is difficult to cause destruction such as blister breakage, breakage of the protrusion, buckling breakage and the like, It is possible to suppress the compression set as small as possible. More preferably, the content of the structural unit derived from butadiene in the rubber component is 80 mass% or more with respect to the rubber component, so that the fracture is less likely to occur and the compression set can be further suppressed. More preferably, it is at least 90 mass% with respect to the rubber component.

In the present invention, the "structural unit derived from butadiene" refers to a partial structure derived from a single 1,3-butadiene molecule present in a polymer obtained by homopolymerization or copolymerization of 1,3-butadiene (monomer) .

The content of the structural unit derived from butadiene in the rubber component is the total amount of the structural units derived from butadiene having the rubber component constituting the rubber component. Structural units derived from butadiene may be contained in polybutadiene rubber and polybutadiene styrene rubber as well as other rubber types.

The content of the structural unit derived from butadiene in the rubber component is 100% by mass when the rubber component is composed of polybutadiene rubber. When the rubber component is composed of polybutadiene styrene rubber, it can be calculated based on, for example, the copolymer composition ratio of butadiene and styrene.

In the case of having other structural units derived from rubber paper butadiene, the content of the structural units derived from butadiene in the rubber component is preferably such that the structural units derived from butadiene contained in the polybutadiene rubber and the polybutadiene styrene rubber, Is the total amount of the structural units derived from the contained butadiene.

The content of the structural unit derived from butadiene in the rubber component can be determined by, for example, extracting a compounding agent such as process oil by Soxhlet extraction (method A described in JIS K 6229 (2013)), Using GC-MS, the calibration curve prepared by rubber or polymer of the composition base and the analytical result (derived from pyrolysis of butadiene or 4-vinyl-1-cyclohexene as BR-derived pyrolysis, butadiene or 4- Vinyl-1-cyclohexene, styrene and the like, the detection peak of butadiene or 4-vinyl-1-cyclohexene, acrylonitrile as pyrolysis products derived from NBR, the detection peak of C3 to C8 paraffins as thermal decomposition products derived from EPDM Etc.) can be used.

Specifically, the content of the structural unit derived from butadiene in the rubber component can be calculated from the detected peak of butadiene or 4-vinyl-1-cyclohexene, which is a thermal decomposition product of a structural unit derived from butadiene. The origins of generation of butadiene or 4-vinyl-1-cyclohexene may be peaks derived from BR, SBR, NBR, liquid rubber or any other origin.

More specifically, analysis can be performed using the detection peaks in which the retention times do not overlap, under the analysis conditions described in JIS K 6231 (2013), JIS K 6231-2 (2013), or the conditions conforming to them. The content of the structural unit derived from butadiene in the rubber component can be measured from the sealing member for high-pressure gas after vulcanization and molding.

As described above, the rubber composition of the present invention may be a rubber component alone or a composition containing a rubber component and a compounding agent, but usually includes a rubber component and a compounding agent. A known compounding agent generally used in the rubber industry may be used within the range of not compromising the object of the present invention.

The type and amount of the compounding agent to be added are not particularly limited. Depending on the type and amount of the compounding agent, when the rubber composition of the present invention is exposed to a high-pressure gas for a long time, Therefore, when the rubber composition of the present invention is subjected to Soxhlet extraction using acetone as a solvent and based on Method A described in JIS K 6229 (2013), the extraction amount of the extract is 12% by mass or less of the rubber composition of the present invention , More preferably 10 mass% or less.

The rubber composition of the present invention may be uncrosslinked, but is usually crosslinked. Further, in the present application, there may be a case where "vulcanization" is used as the language of agreement with "bridging". That is, the term &quot; vulcanization &quot; as used herein means not only crosslinking the rubber component using sulfur or a vulcanization accelerator, but also crosslinking the rubber component using a crosslinking agent other than sulfur such as organic peroxide.

The crosslinking (vulcanization) method is not particularly limited insofar as the object of the present invention is not impaired.

A more preferred cross-linking (vulcanization) process is a cross-linking, peroxide vulcanization using organic peroxides. That is, the rubber composition of the present invention is preferably a peroxide vulcanization. The peroxide vulcanizate has improved compression set characteristics and is preferable in FCV-related applications because there is no fear of sulfur poisoning of the fuel cell catalyst. Peroxide vulcanizates can be obtained by subjecting rubber compositions to Sulfur extraction by Soxhlet extraction or by GC-MS or FT-IR analysis of organic peroxide residues (degradation products) by fluorescent X-ray analysis of the rubber composition And the like.

The organic peroxide is not particularly limited as long as it is generally usable in rubber, and examples thereof include benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, ditert-butyl peroxide, tert- Tert-butyl peroxide, butyl cumyl peroxide, dicumyl peroxide, 1,1-di (tert-butylperoxy) -3,3,5-trimethylcyclohexane, 2,5- (Tert-butylperoxyisopropyl) benzene, 2,5-dimethyl-2,5-di (tert-butylperoxy) Tert-butylperoxybenzoate tert-butylperoxyisopropylcarbonate, n-butyl-4,4-di (tert-butylperoxy) valerate and the like are used. These organic peroxides may be used alone or in combination of two or more.

The amount of the organic peroxide to be blended may be appropriately determined depending on the kind of the organic peroxide and the like, but is usually from 0.2 to 8 parts by mass, preferably from 1 to 5 parts by mass, based on 100 parts by mass of the rubber component.

Specific examples of the other compounding agents include fillers such as talc, calcium carbonate, calcium carbonate and the like; processing aids such as stearic acid, palmitic acid, paraffin wax, and process oil; Metal oxides such as zinc oxide and magnesium oxide, antioxidants, plasticizers, scorch inhibitors and the like. These compounding agents may be used alone or in combination of two or more.

The rubber composition of the present invention may contain a reinforcing agent such as carbon black or silica. The reinforcing agent may be used alone or in combination of two or more.

When carbon black as a reinforcing agent is compounded, it is preferable that the carbon black contains at least one of SAF, ISAF and HAF, which are hard carbon species, because it imparts strength to the rubber.

Further, it is preferable to include at least one of the soft carbon species FEF, GPF, HMF and SRF for the compression set property of the rubber.

The hard carbon species and the soft carbon species are preferably used in combination.

Also, SAF, ISAF, HAF, FEF, GPF, HMF, and SRF are abbreviations of carbon black classified in ASTM standard D-1765-82a in the United States.

The amount of the carbon black to be added can be appropriately selected according to the purpose, but it is preferably 50 parts by mass or more, more preferably 100 parts by mass or more, based on 100 parts by mass of the rubber component from the viewpoints of strength, hardness and abrasion resistance.

In addition, the rubber composition of the present invention may contain a process oil, and when containing a process oil, the process oil is preferably a paraffinic or naphthenic oil.

The addition amount may be appropriately determined within a range that does not impair the object of the present invention. However, when the high-pressure gas is exposed for a long time, the process oil may be pushed out and the property change of the rubber composition may become a problem. Is preferably 12 mass% or less, more preferably 10 mass% or less, in the rubber composition or vulcanized rubber composition which is difficult to cycle. Further, the amount of the process oil can be measured by Soxhlet extraction (method A described in JIS K 6229 (2013)).

In order to further suppress the change in physical properties due to material extrusion due to high-pressure gas exposure, it is preferable to use saff (paclitaxel) or liquid rubber as a substitute for the process oil. Saab (paclitaxel) is preferably saff (paclitaxel) treated with peroxidic sulfur-free peroxide, and the liquid rubber is preferably used in view of the compatibility of the liquid butadiene rubber or liquid styrene butadiene rubber with polybutadiene and / or polybutadiene styrene desirable.

The liquid rubber which can be used as a substitute for the process oil is, for example, a rubber such as liquid polybutadiene LBR-300, LBR-302B, LBR-305, LBR-307, LBR-352 and LBR- And grades for rubber such as L-SBR-820 and L-SBR-841, which are liquid styrene butadiene rubbers of Kuraray Co., Ltd., are suitably used.

In addition, the rubber composition of the present invention may contain an anti-aging agent, and one or more anti-aging agents may be used in combination. The antioxidant is not particularly limited, and conventionally known ones can be used, but those containing a nitrogen atom are preferred.

Specifically, an amine ketone type, an aromatic secondary amine type, an imidazole type and the like are preferable. Such an antioxidant is preferable because it improves the dispersing effect of carbon black when the carbon black is added as a compounding agent in addition to the anti-aging effect.

Further, when exposed to a high-pressure gas for a long time, an anti-aging agent having a reactive functional group such as a methacryl group is preferable because the anti-aging agent may be pushed out and the property of the rubber composition may change.

In addition, the rubber composition of the present invention may contain a co-crosslinking agent. Examples of the co-crosslinking agent include polyfunctional unsaturated compounds and the like. The polyfunctional unsaturated compound may be used alone or in combination of two or more.

Examples of the polyfunctional unsaturated compound include polyfunctional unsaturated compounds such as quinonedioxime (for example, p-quinone dioxime), methacrylate polyfunctional unsaturated compounds (for example, ethylene glycol dimethacrylate Allyl polyfunctional unsaturated compounds (e.g., diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, triallyl isocyanurate, triallyl isocyanurate, triallyl isocyanurate, (Maleimide, phenylmaleimide, N, N'-m-phenylene bismaleimide and the like), maleic anhydride, divinylbenzene , Vinyltoluene, 1,2-polybutadiene, and the like.

Of these, triallyl isocyanurate and diethylene glycol dimethacrylate are preferable in order to reduce compression set of the sealing member.

When a co-crosslinking agent (particularly, a polyfunctional unsaturated compound) is used, it is preferably 0.1 to 20 parts by mass, particularly preferably 1 to 5 parts by mass, based on 100 parts by mass of the rubber component.

One preferred embodiment of the rubber composition of the present invention is a rubber composition comprising a polybutadiene rubber and / or a polystyrene butadiene rubber, a crosslinking agent, and a reinforcing agent. Examples of such a rubber composition include a rubber composition containing a polybutadiene rubber and / or a polystyrene butadiene rubber, an organic peroxide, and carbon black.

As another preferable embodiment of the rubber composition of the present invention, for example, the rubber composition further comprises carbon black, the rubber component in the rubber composition is 20 to 66 mass%, the rubber component is 100 mass% , And a rubber composition having a carbon black content of 50 to 400 parts by mass.

As another example, it is preferable that the rubber composition further contains carbon black, the rubber component in the rubber composition is 20 to 66 mass% with respect to the rubber composition, the carbon black is 50 to 400 mass , And a rubber composition having an acetone extraction amount of the rubber composition of 12 mass% or less. Such a rubber composition has a small compression set. Further, changes in physical properties due to rapid pressure reduction or the like caused by high-pressure gas exposure are suppressed, which is more preferable.

The production method of the rubber composition of the present invention is not particularly limited and may be selected from conventionally known methods depending on the purpose. For example, the rubber composition of the present invention is produced by kneading using a kneader such as an intermix, a kneader, a Banbury mixer, or an open roll. In the case of vulcanization molding, for example, an injection molding machine, a compression molding machine, a vulcanizing press, or the like is used. In general, vulcanization molding is performed by heating at about 150 to 200 DEG C for about 3 to about 60 minutes, and if necessary, oven heating (secondary vulcanization) for heating at about 80 to 150 DEG C for about 1 to 24 hours is performed.

2. Sealing member for high-pressure gas

Further, the present invention relates to a sealing member for a high-pressure gas (hereinafter sometimes referred to as &quot; sealing member of the present invention &quot;) molded using the rubber composition of the present invention. That is, the sealing member of the present invention has the rubber composition of the present invention. In the sealing member of the present invention, the rubber composition of the present invention may be used as it is, or may be used after crosslinking or molding, depending on the purpose. Further, the rubber composition of the present invention may be molded by using alone, or may be molded by using it in combination with other materials. The production method is not particularly limited, and the sealing member of the present invention can be produced by suitably selecting a conventionally known method according to the purpose. Further, the sealing member for high-pressure gas needs only to prevent the gas from leaking substantially, and it is not necessary to seal the gas so that the gas does not completely leak from the container such as the tank.

The shape of the sealing member of the present invention is not particularly limited as long as it is a molded article, and its shape can be appropriately selected in accordance with the purpose.

Specific examples of the sealing member of the present invention include an O-ring, a packing, a gasket, and a hose, and suitably one selected from the group consisting of an O-ring, a packing, and a gasket.

The hardness of the sealing member of the present invention is preferably not less than 60 durometer A hardness, more preferably not less than 80 durometer A hardness, in view of the effect of suppressing the volume expansion rate at the time of rapid pressure depression and the improvement of abrasion resistance after high- , And a durometer A hardness of 85 or more. If the Durometer hardness is less than 60, the volume expansion becomes very large at the time of rapid pressure reduction after the high pressure gas exposures. Therefore, for example, in the case of an O-ring, it is possible to prevent the "protruding failure" caused by protruding from the O-ring groove, the "buckling failure" caused by the expansion in the circumferential direction, Destruction "is likely to occur.

The sealing member of the present invention does not generate blisters even when exposed to high-pressure gas, and has a characteristic of being excellent in low-temperature characteristics. Further, the sealing member of the present invention has a small permanent compression set and a good wear resistance (sliding property). Therefore, the sealing member of the present invention can be used as a sealing member of various high-pressure gas appliances, and is particularly suitable as a sealing member of a device handling hydrogen gas or helium gas.

Examples of the high-pressure gas appliances include a high-pressure hydrogen container for a fuel cell vehicle, a member for a hydrogen station, and a high-pressure helium container for the space industry. For example, a storage high-pressure hydrogen gas (for example, Or more hydrogen gas), a sealing member for a hydrogen station, a sealing member for high-pressure helium sealing in a space industry, and the like. The high-pressure gas appliance will be described later in detail.

The term &quot; high-pressure gas &quot; means a compressed gas or a liquefied gas specified in the high-pressure gas security method. Specifically, the "compressed gas" is a gas having a pressure (gauge pressure) of 1 MPa or more at a commercial temperature or a gas having a pressure of 1 MPa or more at 35 ° C. (excluding compressed acetylene gas). The term &quot; liquefied gas &quot; means a gas having a pressure of 0.2 MPa or more at a commercial temperature or a gas having a temperature of 35 DEG C or less when the pressure is 0.2 MPa.

In the conventional sealing member, although it is possible to seal a liquefied gas (for example, liquid helium or the like) of 0.2 MPa, it is difficult to seal a high pressure gas such as 1 MPa (particularly hydrogen or helium gas). On the other hand, the sealing member of the present invention can seal such extremely high pressure gas (particularly, hydrogen or helium gas), and has excellent sealing properties. Therefore, the sealing member of the present invention is more preferably used for sealing a high-pressure gas (compressed gas) of 1 MPa or more.

The pressure resistance of the sealing member for high-pressure gas of the present invention is suitably applied to use in a high-pressure gas of 1 MPa or more. In particular, excellent pressure-resistant sealing performance can be exhibited even under the use conditions of not less than 35 MPa (for example, not less than 50 MPa, not less than 70 MPa, and not less than 90 MPa)

Further, &quot; 1 MPa &quot; is the pressure in the compressed gas (gas).

The sealing member for a high-pressure gas of the present invention exhibits excellent sealing performance even in a wide temperature range (particularly in a low-temperature environment), and is suitable for use at -70 캜 to 100 캜 (preferably -40 캜 to 85 캜).

When the sealing member of the present invention is used to seal a high-pressure gas, the sealing member of the present invention may be sealed as a single member, or a conventional grease may be used in combination. Alternatively, It is also possible to do.

When the grease is used in combination, there is no particular limitation on the grease, and silicon or fluorine-based grease may be used. Particularly, when fluorine-based grease is used, ozone deterioration such as when preserving a product is suppressed is particularly preferable. For example, various grades of the Krytox series manufactured by DuPont, various grades of moly coats made by Dow Corning Toray, and the like can be suitably used. For example, the effect of improving the ozone resistance by fluorine grease application is remarkable, and the ozone concentration is 50 pphm, the test temperature is 40 占 폚 and the crack is not observed for 120 hours or more under the 20% deformation condition (JIS K 6259 (2013) test method) Durability. Further, ozone resistance may be increased by adding wax, which is used in conventional automobile tires or the like, to the inside of the rubber and by blooming the wax.

When used in combination with a backup ring, the backup ring is not particularly limited and may be used for a backup ring of a conventional fluororesin (PTFE, PFA, PVDF, etc.) or nylon (nylon 6, nylon 66, MC nylon), polyester, Resin, or a backup ring made of a composite of fibers such as glass fiber, resin fiber, carbon fiber, and resin for backup ring may be used.

3. High pressure gas appliances

Further, the present invention relates to a high-pressure gas appliance (hereinafter sometimes referred to as "high-pressure gas appliance of the present invention") having a sealing member of the present invention. That is, the high-pressure gas appliance of the present invention is a high-pressure gas appliance having a sealing member having a rubber composition, wherein the rubber component in the rubber composition comprises polybutadiene rubber and / or polystyrene butadiene rubber, Lt; 0 &gt; C or lower. The sealing member and the rubber composition of the high-pressure gas appliance are as described above, and the preferred embodiment is also the same. Such a high-pressure gas appliance of the present invention can suppress gas leakage even when used in a wide temperature range and the use of sliding portions, and can be stably used.

A high pressure gas device is a device having a point where a high pressure gas contacts. The high-pressure gas appliance of the present invention is preferably a high-pressure gas container or a high-pressure gas piping device.

The high-pressure gas appliance of the present invention preferably has a pressure resistance of 1 MPa or more, more preferably 35 MPa or more. It is also possible to have pressure resistance of 50 MPa or more, 70 MPa or more, 90 MPa or more, or the like.

As described above, the sealing member of the present invention can suitably seal hydrogen and helium gas. Therefore, the high-pressure gas appliance of the present invention is preferably a device having a portion in contact with high-pressure hydrogen or high-pressure helium, and it is preferable to use a high-pressure hydrogen container, a high-pressure helium container, a piping device for high-pressure hydrogen, It is more preferable that any one is selected. Further, any one selected from the group consisting of a high-pressure hydrogen container, a high-pressure helium container, a piping device for high-pressure hydrogen, and a piping device for high-pressure helium, and is preferably a device having a pressure resistance of 1 MPa or more.

A high-pressure gas container is a gas container filled with a high-pressure gas. A high-pressure hydrogen container is a container filled with high-pressure hydrogen gas. It is preferable that the container is filled with hydrogen at a high pressure of 1 MPa or more. A hydrogen storage tank (for example, a high-pressure hydrogen tank for a fuel cell vehicle) filled with hydrogen of 70 MPa or more as a high-pressure hydrogen container, and an accumulator for a hydrogen station. A high pressure helium vessel is a vessel filled with high pressure helium. It is preferable that the container is filled with helium at a high pressure of 1 MPa or more. As a high-pressure helium vessel, there is a high-pressure helium vessel for the space industry.

Piping equipment for high-pressure gas is a device installed in piping that contacts high pressure gas such as piping for transporting high-pressure gas between accumulator and dispenser. Piping equipment for high-pressure hydrogen is equipment installed in piping where high-pressure hydrogen contacts. High-pressure Helium piping is a device installed in piping that high-pressure helium contacts.

Specifically, it is preferable that the high-pressure gas appliance of the present invention is any one selected from the group consisting of a tank, an accumulator, a valve, a joint, a coupler, a safety valve, a check valve and a pressure control valve.

Further, the high-pressure gas appliance of the present invention can be a hydrogen station device such as a hydrogen production device, a hydrogen compressor, an accumulator, a hydrogen dispenser, and a piping device for high-pressure hydrogen connecting between these devices. Each device for the hydrogen station has a different environment for use in each device. For example, in an accumulator, hydrogen of about 90 MPa is stored at about -20 ° C to 50 ° C. In the hydrogen dispenser, since the temperature is raised during the hydrogen charging, it is cooled to -40 ° C as pre-cooling. The high-pressure gas appliance of the present invention can operate stably by suppressing the leakage of the high-pressure gas even in the case of a high-pressure gas appliance having different operating environments such as pressure, temperature, and sliding.

4. The sealing method of the present invention

The present invention also provides a method of sealing a high pressure gas of a high pressure gas appliance using a sealing member, wherein the sealing member is molded using a rubber composition, wherein the rubber component in the rubber composition is a polybutadiene rubber and / Butadiene rubber, and the rubber composition is a rubber composition having a glass transition point of -65 占 폚 or lower (hereinafter sometimes referred to as "sealing method of the present invention"). That is, it is a sealing method for preventing the high-pressure gas from leaking from the high-pressure gas appliance by using the sealing member of the present invention described above. In addition, preferred embodiments of the rubber composition for molding the sealing member and the sealing member are as described above. The high-pressure gas appliance is as described above, and the preferred embodiment is also the same.

More preferably, the high-pressure gas used in a high-pressure gas device used at -70 ° C to 100 ° C (preferably at -40 ° C to 85 ° C) or the high-pressure gas device generating a temperature difference of 65 ° C to 125 ° C For example.

It is also preferable to arrange the sealing member of the present invention in the sliding portion of the high-pressure gas appliance and seal it. The sealing member of the present invention is attached to the sliding portion of the high-pressure gas appliance used at -70 ° C to 100 ° C (preferably, -40 ° C to 85 ° C) or the high-pressure gas appliance which generates the temperature difference of 65 ° C to 125 ° C It is more preferable to arrange and seal it. As described above, the sealing member of the present invention can maintain rubber elasticity even in a temperature range from a low temperature to a high temperature, and is excellent in abrasion resistance and blister resistance. Therefore, by using the sealing method of disposing the sealing member of the present invention in the sliding portion of the high-pressure gas appliance, leakage of high-pressure gas can be prevented even in a sliding portion (particularly, a sliding portion in use at a low temperature) .

The sealing method of the present invention is suitable when the high-pressure gas is hydrogen or helium. Further, the sealing method of the present invention is suitable for high-pressure gas having a pressure of 1 MPa or more and more suitable for a high-pressure gas having a pressure of 35 MPa or more. Further, a high-pressure gas such as 50 MPa or more, 70 MPa or more, 90 MPa or more can be sealed.

Example

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the present invention is not limited to the following Examples, and it is of course possible to carry out the present invention by appropriately modifying it within the range satisfying the above- All of which are included in the technical scope of the present invention.

<Examples>

1. Component

Each component used in Examples 1 and 2 is listed below.

(1) Rubber

(Content of vinyl acetate of 7 to 13 mol%) (diisocyanate), dien NF35R (sheath content 35 mol%, trans content 57.5 mol%, vinyl content 7.5 mol% (infrared data)) (manufactured by Asahi Chemical Industry Co., Ltd.) Lt; SEP &gt;

Solution polymerization SBR: Tuftden 2000R (styrene amount: 25 wt%) (manufactured by Asahi Kasei Corporation)

NBR: JSR NBR N260S (amount of acrylonitrile: 15 wt%) (manufactured by JSR Corporation)

EBT (ethylene-butene rubber-diene copolymer rubber): Mitsui EBT-K-9330M (manufactured by Mitsui Chemicals, Inc.)

EPDM: Mitsui EPT-3070 (manufactured by Mitsui Kagaku K.K.)

Liquid rubber: Curaprene LBR-307B (Kuraray Co., Ltd.)

(2) Carbon black

Syst 9 (manufactured by Tokai Carbon Co., Ltd.), Syst S (manufactured by Tokai Carbon Co., Ltd.)

(3) Crosslinking agent (organic peroxide)

C-8A (manufactured by Shin-Etsu Chemical Co., Ltd., 2,5-dimethyl-2,5-bis (tert-butylperoxy) hexane 80%

(4) Other compounding agents

Anti-aging agent: Nocrack G-1 (manufactured by Ouchi Shokokagaku Kogyo K.K.)

(Polyfunctional unsaturated compound): NK ester 2G (manufactured by Shin Nakamura Kagaku Kogyo K.K., diethylene glycol dimethacrylate)

Process oil: Diana process oil NS-100 (manufactured by Idemitsu Kosan Co., Ltd.)

Processing aid: Stearic acid (manufactured by Wako Pure Chemical Industries, Ltd.)

Metal oxide: 2 kinds of zinc oxide (manufactured by HAKUSITE Co., Ltd.)

&Lt; Example 1 >

1. Preparation of rubber composition and sealing member

The components shown in Table 1 were kneaded by using a kneader to prepare rubber compositions of Examples 1-1 to 1-8. Next, the rubber compositions of Examples 1-1 to 1-8 were each press-molded at 170 占 폚 by a press molding apparatus to obtain a measurement sample and a sealing member.

The measurement samples for use in the state property measurement, the glass transition point measurement and the exposure test were prepared by punching a sheet-shaped molded article having a thickness of 2 mm in a shape corresponding to each evaluation item. A measurement sample for evaluation of compression set was prepared in accordance with JIS K 6262 (2013). The sealing member was manufactured so as to have the shape of an O-ring.

2. Evaluation

The properties of the rubber composition and the sealing member of Examples 1-1 to 1-8 were evaluated as follows.

(1) State properties (hardness, tensile strength and elongation)

The hardness of the sealing member was measured according to JIS K 6253-3 (2013) using a Type A durometer. The tensile strength and elongation were also measured according to JIS K 6251 (2013).

(2) Compression permanent deformation (heat resistance, cold resistance)

(Compression ratio is based on JIS B 2401-1 Annex JC (2013)) at a test temperature (85 캜 or -40 캜), and the compression set of the sealing member after being stored at the same temperature for 24 hours is referred to as JIS K 6262 (2013). The compression set is a value measured after 30 minutes from the standstill at room temperature after compression and decompression at a compression temperature of 85 ° C. At a compression temperature of -40 占 폚, it is a value measured 30 minutes after left under an environment of -40 占 폚 after decompression.

(3) Glass transition temperature

The glass transition temperature of the sealing member was measured using DSC based on JIS K 6240 (2013). The measurement conditions are a nitrogen flow rate of 50 mL / min and a temperature raising rate of 20 DEG C / min. Further, at the time of DSC measurement, the temperature correction by the standard substance (cyclohexane) described in Annex JB of JIS K 6240 (2013) and the adjustment of the baseline described in JIS K 7122 (2014) were carried out in advance.

(4) Content of structural unit derived from butadiene in the rubber component

The mass% of the structural units derived from butadiene in the rubber component in the rubber composition of this example was calculated from the styrene content of the SBR based on the manufacturer, the amount of acrylonitrile in the NBR, and the combination of the rubber composition.

(5) Water softening

Prior to the tests (5-1) to (5-4), it was confirmed that there was no gas leakage or sample breakage in the evaluation system by using a high-pressure gas of helium. The evaluation method is the same as the following (5-1) to (5-4) except that helium is used instead of hydrogen.

(5-1) Exposure test

The sample for measurement was a dumbbell shape No. 7 specified in JIS K 6251 (2013).

The length of one side of the sample for measurement (L0) was previously measured at room temperature.

Next, the sample for measurement was placed in a pressure vessel (capacity: 100 mL), exposed to hydrogen at 90 MPa for 16 hours, at a test temperature (room temperature or -40 ° C.) and then depressurized rapidly I did. Thereafter, a sample was taken out quickly (room temperature), and a measurement sample for 10 minutes after depressurization was taken at room temperature together with the scale. From the photographs of the sample for measurement and the scale, the length of the same portion as the pre-measured portion of the measurement sample was measured (L1), and the volume expansion rate (%) was calculated according to the following expression.

Volume Expansion Rate (%) = (L1 / L0) ³ 100

In addition, the presence or absence of blister breakage was observed by photographing after photographing and visual observation of an actual sample after exposure. &Quot; x &quot; when blister fracture was present, and &quot; o &quot; when no blister fracture was observed.

(5-2) Hydrogen pressure cycle test

Fig. 1 is a schematic view of a section of a pressure proof test apparatus used in the test. Fig. 2 is a photograph of the apparatus before attaching the jig having the gas supply port and the leak detecting globe, and Fig. 3 is a schematic diagram of the cross section of the apparatus before attaching the jig having the gas supply port and the leak detecting globe. As shown in Fig. 1, in the apparatus for pressure resistance test used in this test, it is possible to detect the supply of high-pressure gas and the leakage of gas by attaching a jig having a gas supply port and a leak detection port after inserting the O-ring.

First, as shown in Fig. 1, a sealing member was installed in a device for internal pressure test. Next, at a test temperature (85 캜 or -40 캜), 6600 times of the hydrogen depressurization cycle was carried out between atmospheric pressure and 90 MPa for one cycle of 6 to 8 seconds. The presence or absence of hydrogen leakage during the test was monitored by a pressure sensor. The damage of the sealing member after the test was visually evaluated. The temperature was adjusted by monitoring the jig surface temperature at which the sealing member was loaded. The hydrogen leakage and the damage state of the sealing member were evaluated according to the following criteria.

&Amp; cir &amp;: When there is no hydrogen leakage and the sealing member is not broken

○: There was no hydrogen leakage or breakage of the sealing member, but when a droplet was observed around the sealing member

DELTA: No hydrogen leakage, but partial breakage of the sealing member occurred significantly

X: When there is hydrogen leakage or when the sealing member is damaged

(5-3) Hydrogen sliding test

First, a part of the existing O-ring of the stem portion which is the shaft of the valve of the commercial valve device (ultra-high-pressure hydrogen gas adaptation valve (valve manufactured by FUJIKIN Co., Ltd.)) was removed and the sealing member of this embodiment was installed instead of the existing O-ring. Next, the test was carried out by sliding the stem, which is the shaft of the valve, from the sealing member by opening and closing the valve 1000 times (opening and closing once and one time for each round of the stem) while filling with 90 MPa of hydrogen at the test temperature (85 캜 or -40 캜) . During the test, the presence of hydrogen leakage during the test was evaluated by monitoring the pressure in the valve. The presence or absence of damage of the sealing member after the test was visually evaluated. The temperature was adjusted by monitoring the housing surface temperature of the valve loaded with the sealing member. The hydrogen leakage and the damage state of the sealing member were evaluated according to the following criteria.

○: When there is no hydrogen leakage and the sealing member is not broken

DELTA: No hydrogen leakage, but partial breakage of the sealing member occurred significantly

X: In the case of hydrogen leakage or the sealing member is broken

(5-4) -65 ℃ high pressure hydrogen sealing test

(5-2) were used. A sealing member was loaded into a device for internal pressure test, and a hydrogen depressurization cycle was performed three times at a test temperature of -65 占 폚, between atmospheric pressure and 90 MPa. Further, the sealing characteristics were confirmed at -65 캜 while filling with hydrogen at 90 MPa for 10 minutes. The presence or absence of hydrogen leakage during the test was monitored by a pressure sensor and evaluated. The damage of the sealing member after the test was visually evaluated. The temperature was adjusted by monitoring the jig surface temperature at which the sealing member was loaded. The hydrogen leakage and the damage state of the sealing member were evaluated according to the following criteria.

○: When there is no hydrogen leakage and the sealing member is not broken

DELTA: No hydrogen leakage, but partial breakage of the sealing member occurred significantly

X: In the case of hydrogen leakage or the sealing member is broken

Table 1 shows the compositions of the rubber compositions of Examples 1-1 to 1-8 and the evaluation results of the above (5-1) to (5-4).

As shown in Table 1, the sealing member of the example of the present invention has good water resistance at low temperature and has no blister breakage and low volume expansion rate in the high-pressure hydrogen exposure test.

In the hydrogen pressure cycling test, there were no hydrogen leaks at both 6600 cycles at -40 ° C (low temperature) and 6600 cycles at 85 ° C (high temperature). The damage of the sealing member after the test was also slight.

With respect to Example 1-1, there was no hydrogen leakage and no breakage of the sealing member as shown in Table 1, but a droplet was observed around the sealing member after the test in the cycle test at the test temperature of 85 캜. In addition, this droplet was part of the process oil (1.5 wt% loss in 14.5 wt%) added as a compounding agent.

In the hydrogen-sliding test, it was possible to seal the sealing member without damaging the sealing member, and without sealing the hydrogen gas at 1000 MPa at 90 MPa, -40 캜 (low temperature), and 1000 MPa at 90 MPa and 85 캜 (high temperature)

Also, at -65 캜 high-pressure hydrogen sealing test, it was possible to seal 90 MPa hydrogen without leakage. Since the test jig design was at -70 캜, the test was carried out at -65 캜 in consideration of safety, but it is considered that sealing at a lower temperature is also possible from the value of the glass transition point.

(5-5) Hydrogen pressure cycle test -2

The sealing member of Example 1-5 was evaluated in the same manner as in (5-2), except that the test temperature was changed from -58 캜 to -50 캜 or from 85 캜 to 110 캜.

The sealing member of Example 1-5 was subjected to an internal hydrogen pressure cycle test at a test temperature of -58 캜 to -50 캜 and it was found that there was no hydrogen leakage even after 1600 tests.

The hydrogen gas pressure cycle test was conducted at a test temperature of 85 ° C to 110 ° C. As a result, no hydrogen leakage was found even after the 6600th test.

The sample was exchanged at each temperature of -40 DEG C, room temperature, and 85 DEG C by an internal hydrogen pressure cycle test (one cycle of hydrogen pressurization and pressure between ambient pressure and 95 MPa) using the sealing member of Example 1-5 I did without. As a result, it was found that there was no hydrogen leakage in the same sample (no sample exchange) after 7600 times at -40 ° C, 6700 times at room temperature, and 38900 times at 85 ° C. From these results, it was found that the durability was high enough to withstand a total pressure of 53200 cycles or more at each temperature.

&Lt; Example 2 >

1. Preparation of rubber composition and sealing member

The components shown in Table 2 were kneaded by using a kneader to prepare rubber compositions of Examples 2-1 to 2-3. Next, the rubber compositions of Examples 2-1 to 2-3 were each press-molded at 170 占 폚 by a press molding apparatus to obtain a measurement sample and a sealing member.

2. Evaluation

(1) state properties and glass transition temperature

The evaluation was conducted in the same manner as in Example 1.

Further, TR 10 (占 폚) was measured by the method according to JIS K 6261 (2013).

(2) -40 캜 high-pressure hydrogen sealing test

The evaluation was carried out in the same manner as in the (-5) C high-pressure hydrogen sealing test (5-4) of Example 1 except that the test temperature was changed from -65 ° C to -40 ° C.

(3) Hydrogen pressure cycle test

A sealing member was installed in the apparatus for pressure resistance test shown in Fig. Next, at -40 ° C, a cyclic test was carried out between hydrogen at normal pressure and 90 MPa at a cycle of hydrogen depressant / depressurization of 6 to 8 seconds per cycle. The presence or absence of hydrogen leakage was monitored by a pressure sensor and evaluated according to the following criteria according to the number of times until hydrogen leakage occurred.

1: 6600+

2: 6000 to 6599 times

3: 1000 to 5999 times

4: 100 to 999 times

5: 0 to 99 times

The evaluation results are shown in Table 2. As shown in Table 2, good results were also obtained in Examples 2-1 to 2-3.

<Comparative Example>

1. Component

The components used in the comparative examples are listed below:

(1) Rubber

(Manufactured by JSR Corporation), JSR NBR N240S (middle nitrile, acrylonitrile amount: 26 wt%) (manufactured by JSR Corporation), NBR: JSR NBR N230SL , JSR NBR N260S (acrylonitrile amount: 15 wt%) (manufactured by JSR Corporation)

EPDM: Esprene 505 (manufactured by Sumitomo Chemical Co., Ltd.), Mitsui EPT 3090EM (manufactured by Mitsui Kagaku K.K.)

(2) Carbon black

Syst 9 (manufactured by Tokai Carbon Co., Ltd.), Syst 3 (manufactured by Tokai Carbon Co., Ltd.), Syst S (manufactured by Tokai Carbon Co., Ltd.)

(3) Crosslinking agent (Organized oxide)

Percumyl D-40 (manufactured by Nippon Oil Co., dicumyl peroxide)

Sulfur (manufactured by Tsurumi Chemical Industry Co., Ltd.)

(4) Other compounding agents

Anti-aging agent: No crack 6C (manufactured by Ouchi Shokokagaku Kogyo Co., Ltd.)

Co-crosslinking agent (polyfunctional unsaturated compound): TAIC (manufactured by Nippon Kayaku Co., Ltd.)

Processing aid: Stearic acid (manufactured by Wako Pure Chemical Industries, Ltd.)

Metal oxide: 2 kinds of zinc oxide (manufactured by HAKUSITE Co., Ltd.)

Active agent: PEG # 4000 (manufactured by Nichiyu K.K.)

Paraffin oil: (Diana Process Oil PW-32, manufactured by Idemitsu Kosan Co., Ltd.)

&Lt; Comparative Example 1 &

1. Preparation of rubber composition and sealing member

The components shown in Table 3 were kneaded by using a kneader to prepare rubber compositions of Comparative Examples 1-1 to 1-6. Next, the rubber compositions of Comparative Examples 1-1 to 1-6 were each press-molded at 170 占 폚 by a press molding apparatus to obtain a sample for measurement and a sealing member.

Further, the shapes of the sample for measurement and the sealing member are the same as those of the embodiment.

2. Evaluation

The properties (state property, glass transition point, exposure test, high-pressure hydrogen-sealing test) of the rubber composition and the sealing member of Comparative Examples 1-1 to 1-6 were evaluated. Measurement of physical properties, measurement of glass transition point and exposure test were made in the same manner as in Example.

The amount of the structural unit derived from butadiene in the rubber component in the rubber composition of Comparative Examples 1-1 to 1-6 was calculated from the acrylonitrile amount of the NBR of the manufacturer and the rubber composition.

In addition, since the rubber compositions of Comparative Examples 1-1 to 1-6 are more likely to break at higher temperatures than the rubber compositions of the Examples, Pressure hydrogen sealability test was carried out at the test temperature (room temperature, -20 占 폚, -30 占 폚 or -40 占 폚). The test was carried out in the same manner as in Example (5-4) except that the test method was changed to -65 ° C and the test temperature was changed to room temperature, -20 ° C, -30 ° C, or -40 ° C.

The composition and evaluation results of the rubber compositions of Comparative Examples 1-1 to 1-6 are shown in Table 3.

As a comparative example, from the results of the high-pressure hydrogen exposure test at room temperature shown in Table 3, the volumetric expansion rate was a result of the increase in hardness and the decrease in volume. And the volume expansion rate was reduced as the content of the structural units derived from butadiene in the rubber component increased. In the high-pressure hydrogen exposure test under the environment of -40 占 폚, blister breakage was observed when the test environment temperature was lower than the glass transition point.

As a comparative example, a sealing test of high-pressure hydrogen was conducted under the negative temperature environments shown in Table 3. However, even if the test environment temperature was not lower than the glass transition point, leakage occurred and a temperature higher than the glass transition point by about 25 ° C- It was suggested that the temperature could be lowered to a sealable temperature.

&Lt; Comparative Example 2 &

As a comparative example of existing products, a conventional O-ring (EPDM for low temperature) was used to cope with a low temperature of a commercially available valve device (an ultra-high pressure hydrogen gas adaptation valve (valve manufactured by FUJIKIN CO., LTD.)) A firing sealing test was carried out. As a result, hydrogen leakage quickly occurred when the housing temperature was adjusted (-40 ° C aiming) and the housing temperature dropped down to -43 ° C.

In the sealing member of the present embodiment, leakage did not occur at all under the same conditions, and high-pressure hydrogen sealing was possible even at -65 ° C as described above. As described above, there is a clear difference between the existing sealing member and the sealing member of the present embodiment, and the superiority is clear.

&Lt; Comparative Example 3 &

1. Preparation of rubber composition and sealing member

Measurement samples and sealing members of Comparative Examples 3-1 to 3-3 were obtained in the same manner as in Comparative Example 1-1, except that each component was used in the mass parts shown in Table 4.

2. Evaluation

As shown in Table 4, the rubber compositions and sealing members of Comparative Examples 3-1 to 3-4 were evaluated for state physical properties, glass transition point, exposure test, resistance to hydrogen pressure cycle test, and resistance to hydrogen sliding test . The state physical properties, the glass transition point and the exposure test were evaluated in the same manner as in Example 1.

The hydrogen pressure cycle test was carried out at room temperature and -40 ° C instead of the test temperatures of 85 ° C and -40 ° C. In addition, the hydrogen-sliding test was carried out at room temperature by adding the test temperatures to 85 캜 and -40 캜.

The evaluation results are shown in Table 4.

In Comparative Example 3-1, blister breakage was observed at room temperature in the high-pressure hydrogen exposure test. In Comparative Examples 3-2 to 3-4, no blister breakage was observed in the high-pressure hydrogen exposure test. The volume expansion was equal to or slightly worse than those of Examples 1-1 to 1-8.

However, in Comparative Examples 3-2 to 3-4, hydrogen leakage was confirmed in an internal hydrogen pressure cycle test at -40 ° C.

In Comparative Examples 3-2 to 3-4, hydrogen leakage was confirmed in the hydrogen sliding test at -40 ° C. Also, in the hydrogen hydrogen sliding test at room temperature or 85 ° C, the friction between the portion contacting the shaft of the up / down valve and the portion contacting with the shaft was large, and the result was severe. The sealing member taken out after the hydrogen-sliding test at 85 캜 showed a state where the sealing member was remarkably partially damaged (abraded) due to friction at a portion contacting with the valve shaft that moved up and down, suggesting a lack of durability.

&Lt; Comparative Example 4 &

1. Preparation of rubber composition and sealing member

100 parts by mass of cryogenic silicon (KE-136Y-U, manufactured by Shin-Etsu Chemical Co., Ltd.), 30 parts by mass of silica (VN3, manufactured by TOSOH CORPORATION), 10 parts by mass of hexamethyldisilazane (manufactured by Wako Pure Chemical Industries, Ltd.) Ltd.) and 1.8 parts by mass of a crosslinking agent (C-8A, Shin-Etsu Chemical Co., Ltd.) were kneaded with a kneader to prepare a rubber composition of Comparative Example 4. [ Then, a sample for measurement and a sealing member were obtained in the same manner as in Comparative Example 1-1.

2. Evaluation

The hardness of Comparative Example 4 was measured in the same manner as in Example 1 to find that it was 87.

The glass transition point of Comparative Example 4 was measured in the same manner as in Example 1, and found to be -125 占 폚.

The sealing property of the sealing member of Comparative Example 4 at -40 캜 was evaluated in the same manner as in Comparative Example 1-1. The sealing member of Comparative Example 4 was sealable even at -40 占 폚.

The amount of abrasion of an abrasive was determined by an abrasion test according to JIS K 6264-2 (2013) A. The abrasion amount of the comparative example 4 was 0.101 (cc / 1000 times / 27.0 N).

Also, the amounts of abrasion of the samples of Examples 1-3 and 1-5 were 0.011 (cc / 1000 times / 27.0 N) and 0.011 (cc / 1000 times / 27.0 N), respectively,

Table 5 shows the evaluation results of hardness (durometer A), glass transition point, amount of wear of the abrasive grains, and sealability at -40 ° C in Examples 1-3, 1-5, and Comparative Example 4. As a result of comparison, the amount of wear of the comparative example 4 was about ten times as large as that of the example 1-3 and the example 1-5. In addition, the amount of wear of the abrasion means that the abrasion is larger as the abrasion amount increases. That is, although the sealing member of Comparative Example 4 can seal high-pressure hydrogen under a low temperature, it is easy to cause wear, and it is not suitable for applications requiring wear resistance such as sliding portions. On the other hand, Examples 1-3 and 1-5 can be suitably used even in applications where abrasion resistance is required, such as sliding parts.

(Industrial availability)

The rubber composition of the present invention is excellent in abrasion resistance, low temperature resistance, heat resistance and blister resistance, and can be used as a sealing member of various high-pressure gas appliances, particularly as a sealing member of a device handling hydrogen gas or helium gas, .

Claims (17)

A rubber composition for use in a sealing member for high-pressure gas sealing a high-pressure gas,
Wherein the rubber component in the rubber composition comprises a polybutadiene rubber and / or a polystyrene butadiene rubber,
Wherein the rubber composition has a glass transition point of not higher than -65 占 폚. The method according to claim 1,
Wherein the high pressure gas is hydrogen or helium. 3. The method according to claim 1 or 2,
Wherein the high-pressure gas is a high-pressure gas of 1 MPa or more. 4. The method according to any one of claims 1 to 3,
Wherein the content of the structural unit derived from butadiene in the rubber component is 70 mass% or more with respect to the rubber component. 5. The method according to any one of claims 1 to 4,
Wherein the polybutadiene rubber is of a sheath type. 6. The method according to any one of claims 1 to 5,
Wherein the rubber composition is a peroxide vulcanization. 7. The method according to any one of claims 1 to 6,
The rubber composition according to claim 1, wherein when the rubber composition is subjected to Soxhlet extraction based on Method A described in JIS K 6229 (2013) using acetone as a solvent, the extraction amount of the extract is 12 mass% or less of the rubber composition. A sealing member for a high-pressure gas molded using the rubber composition according to any one of claims 1 to 7. 9. The method of claim 8,
Wherein the sealing member for high-pressure gas is any one selected from the group consisting of an O-ring, a packing, and a gasket. A high-pressure gas appliance comprising the sealing member for high-pressure gas according to claim 8 or 9. 11. The method of claim 10,
Wherein the high-pressure gas device is a high-pressure gas container or a high-pressure gas pipe device. The method according to claim 10 or 11,
Wherein the high-pressure gas device is any one selected from the group consisting of a high-pressure hydrogen container, a high-pressure helium container, a high-pressure hydrogen pipe device, and a high-pressure helium pipe device. 13. The method according to any one of claims 10 to 12,
Wherein the high-pressure gas device is any one selected from the group consisting of a tank, an accumulator, a valve, a joint, a coupler, a safety valve, a check valve, and a pressure control valve. 14. The method according to any one of claims 10 to 13,
Wherein the high-pressure gas appliance has a pressure resistance of 1 MPa or more. A method of sealing a high-pressure gas of a high-pressure gas appliance using a sealing member,
Wherein the sealing member is molded using a rubber composition,
Characterized in that the rubber component in the rubber composition comprises a polybutadiene rubber and / or a polystyrene butadiene rubber, and the rubber composition is a rubber composition having a glass transition point of -65 占 폚 or lower. 16. The method of claim 15,
Wherein the high pressure gas is hydrogen or helium. 17. The method according to claim 15 or 16,
Wherein the high-pressure gas is a high-pressure gas of 1 MPa or more.

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