CN110953415A

CN110953415A - Joint with sealing member

Info

Publication number: CN110953415A
Application number: CN201910911494.1A
Authority: CN
Inventors: 上田彰; 吉田纱也佳; 黑须宽; 铃木敏充; 岩崎宏文
Original assignee: Nippon Valqua Industries Ltd; Ihara Science Corp
Current assignee: Nippon Valqua Industries Ltd; Ihara Science Corp
Priority date: 2018-09-27
Filing date: 2019-09-25
Publication date: 2020-04-03
Anticipated expiration: 2039-09-25
Also published as: JP7368936B2; CN110953415B; JP2020051540A

Abstract

The present invention provides a joint with a sealing member, which comprises: the joint includes a hollow joint body, a hollow pipe member having a flared end at one end, a coupling member for coupling the joint body and the pipe member, a seal member disposed between the joint body and the pipe member, and grease applied to surfaces of the joint body and the pipe member facing the ends of the seal member. The sealing member is formed from a crosslinked product of a rubber composition for a sealing member, which contains 50 to 140 parts by mass of silica and 10 to 50 parts by mass of a silane coupling agent per 100 parts by mass of a rubber component.

Description

Joint with sealing member

Technical Field

The present invention relates to a joint with a sealing member.

Background

A rubber seal for an apparatus for storing high-pressure hydrogen gas has a problem in that a foaming (blister) phenomenon is easily generated. The foaming phenomenon is a phenomenon in which a gas that has permeated into the rubber due to high pressure is influenced by rapid decompression at high temperature and expands while being retained in the rubber, and the rubber material is broken.

International publication No. 2007/145313 and international publication No. 2008/001625 disclose a rubber composition in which silica is blended as a reinforcing material in a silicone rubber. Further, Japanese patent laid-open publication No. 2015-206002 discloses a rubber composition in which carbon black is blended into an ethylene-propylene-diene rubber (EPDM). Jp 2015-108104 a discloses an O-ring made of EPDM containing carbon black and silica, and international publication No. 2003/104317 discloses an elastomeric compound containing carbon black and silica powder (microsilica).

In a high-pressure hydrogen plant, the pressure of hydrogen to be treated gradually increases, and a joint with a sealing member having more excellent sealing properties at low and high temperatures is required. However, a composition having excellent blistering resistance at high temperatures is poor in low temperature properties (recovery properties at low temperatures), and a joint with a sealing member satisfying both properties has not yet been realized.

Disclosure of Invention

The invention aims to provide a joint with a sealing member, which has good sealing performance for high-pressure gas at high temperature and low temperature.

The present invention includes the following joint with a sealing member.

[1] A joint with a seal member, comprising: the joint member comprises a hollow joint body, a hollow pipe member having a flared end at one end, a connecting member for connecting the joint body and the pipe member, a sealing member disposed between the joint body and the pipe member, and grease applied to the surfaces of the joint body and the pipe member facing the ends of the sealing member, wherein the sealing member is formed from a crosslinked product of a rubber composition for a sealing member containing 50 to 140 parts by mass of silica and 10 to 50 parts by mass of a silane coupling agent per 100 parts by mass of a rubber component.

[2] The joint with a sealing member according to item [1], wherein the flare shape is a tapered shape or a flange shape.

[3] The joint with a sealing member according to [1] or [2], wherein the joint body has a groove for receiving the sealing member.

[4] The joint with a seal member according to any one of [1] to [3], wherein the joint body further has a structure for connecting to another pipe member.

[5] The joint with a sealing member according to any one of [1] to [4], wherein the sealing member further contains carbon black in an amount of 40 parts by mass or less per 100 parts by mass of the rubber component.

[6] The joint with a sealing member according to any one of [1] to [5], wherein the rubber component is an ethylene-propylene-diene rubber.

[7] The joint with a sealing member according to any one of [1] to [6], wherein the sealing member is an O-ring.

[8] The joint with a seal member according to any one of [1] to [7], wherein the grease has a kinematic viscosity at 25 ℃ of 6000 to 100 ten thousand cSt.

[9] The joint with a seal member according to any one of [1] to [8], further comprising a backup ring.

According to the present invention, a joint with a seal member having excellent sealing properties for high-pressure gas at high and low temperatures can be provided.

Drawings

Fig. 1 is a partially cutaway front view showing a connection state of one form of a joint with a seal member.

Fig. 2 is a partially cutaway front view showing a connection-released state of one form of a joint with a seal member.

Fig. 3 is a partially cutaway front view showing another form of a joint with a seal member.

Fig. 4 is a partially cutaway front view showing another form of a joint with a seal member.

Fig. 5 is a partially cutaway front view showing another form of a joint with a seal member.

Fig. 6 is a partially cutaway front view showing another form of a joint with a seal member.

Fig. 7 is a schematic diagram showing an example of the flare shape of the end portion of the pipe member.

Fig. 8 is a schematic sectional view of an installation portion of the seal member.

Fig. 9 shows a test process chart in the pressure test of the seal member.

Fig. 10 shows a test process chart of a low-temperature test of the joint with the seal member.

Fig. 11 is a process chart showing a blister resistance test and a low temperature test of a joint with a sealing member.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same reference numerals are used for the same or corresponding portions. Fig. 1 shows a connection state of one embodiment of the joint with a sealing member 10 of the present invention, and fig. 2 shows a connection release state thereof. The joint 10 with a sealing member can connect the hollow pipe member 1 and another member (for example, another pipe member 2) to communicate a fluid therebetween. The joint with sealing member 10 includes: a hollow pipe member 1, a hollow joint body 3, a coupling member 5 for coupling the joint body 3 and the pipe member 1, and a seal member 4 disposed between the joint body 3 and the pipe member 1.

< pipe member, joint body, and connecting member >

The pipe member 1 has a flare shape portion 1a at one end portion, i.e., an end portion facing the joint body 3. Examples of the flare shape include a tapered shape, a flange shape, a curved surface shape, a stepped (stepped) shape, a double flare (double flare) shape, and an O-ring flare shape as shown in fig. 7. From the viewpoint of sealability and ease of connection and disconnection, the shape of the flare applied to the pipe member 1 is preferably a tapered shape or a flange shape, and more preferably a flange shape.

In the case where the pipe member 1 has a flange shape, the pipe member 1 can slide in a direction (direction B in fig. 2) orthogonal to the longitudinal direction (direction a in fig. 2) of the fluid flow in a state where the male screw portion 3a is not screwed into the female screw portion 5B (a state where the screwing is released). A mechanism for displacing at least one end portion of the pipe member 1 in the direction B may be provided, but the pipe member 1 may be fixed with a degree of play to the extent that it can slightly slide in the direction B without using a special mechanism. Since the pipe member 1 is slidable, there is no need to retreat the pipe member 1 in the longitudinal direction (direction a) when releasing the connection between the pipe member 1 and the other pipe member 2, and there is a tendency for workability to be excellent, for example, there is no concern that the space efficiency of the piping facility may be deteriorated or increased in size, or the connection between the pipe member 1 and another piping unit may be hindered. In addition, the pipe member 1 can be easily disconnected from the other pipe member 2. The end face of the flare shape portion 1a is preferably a flat face that does not interfere with the end face of the male screw portion 3a during relative movement of the pipe member 1 with respect to the joint body 3. The end surface of the male screw portion 3a is preferably a surface having no convex portion and no concavity and convexity other than the groove 3d for accommodating the seal member 4.

The flare shape portion 1a may be formed integrally with the pipe member 1 by, for example, applying known flaring to a thin pipe body 1 c. The flaring process is a generic term for a process of expanding the pipe end from the inside to the outside. Examples of the flaring include tapering, flanging, curving, stepping, double flaring, and O-ring flaring. Further, the flare shape portion 1a may be formed by fitting another member having a flare shape to the tube main body 1c by welding or the like. Further, the pipe member 1 may be a spiral flange. From the viewpoint of improving the strength and extending the life of the pipe member 1, the pipe member 1 preferably has a sleeve 1b that is swaged and fixed in a state of being positioned to partially overlap the flare shape portion 1 a.

The coupling member 5 is not particularly limited as long as it has a structure for coupling the joint body 3 and the pipe member 1, and may be, for example, a nut having excellent compactness. In this case, the joint body 3 has an external thread portion 3a formed at one end portion, that is, an end portion facing the pipe member 1, and the coupling member 5 has: an engaged portion 5a that is engaged with the flare shape portion 1a from the opposite side of the portion of the pipe member 1 facing the joint body 3 and has an inner diameter smaller than the outer diameter of the flare shape portion; and a female screw portion 5b having an inner diameter larger than an outer diameter of the flare-shaped portion, into which the male screw portion 3a of the joint body 3 is screwed. The pipe member 1 is inserted into the coupling member 5, and the engaged portion 5a engages with the flare-shaped portion 1a from the opposite side (right side in the drawing) of the portion of the pipe member 1 facing the joint main body 3, thereby preventing the coupling member 5 from separating from the pipe member 1 toward the joint main body 3. Further, the male screw portion 3a of the joint body 3 facing the pipe member 1 can be screwed into the female screw portion 5b of the coupling member 5. The coupling member may be a clamp (clamp), a clip (clip), a bolt, or the like, in addition to the nut. The joint main body 3 and the pipe member 1 may be directly joined by an adhesive or screwed.

The joint main body 3 may also have a configuration for connecting with another pipe member 2, such as an internal threaded portion 3 b. Such a configuration is more preferably provided at the other end portion of the joint main body 3, i.e., an end portion different from the end portion facing the seal member 4. The other end of the joint body 3 may be provided with a male screw portion or other connection means to be connected to another pipe member 2. In this case, the joint main body 3 may be connected to the other pipe member 2 by a connection mechanism provided in the other pipe member 2 or a connection mechanism prepared separately from the joint main body 3 and the other pipe member 2. The other pipe member 2 may be a member directly formed on a manifold (manifold) or the like. In this case, the opening may be an opening other than a pipe shape. A gripped part 3c having a large hexagonal outer shape may be formed between the external thread part 3a and the internal thread part 3 b. The gripped portion 3c is suitable for gripping with a tool such as a wrench.

As shown in fig. 3, as another form of the joint with a sealing member of the present invention, the joint body 3 may be connected to a device 7a such as a tank (tank). In addition, as shown in fig. 4, the joint body 3 may be connected with a valve 8a (including a needle valve, a ball valve, etc.). In this case, the joint main body 3 may be integrally attached to the device 7a or the valve 8a, or the other end portion of the joint main body 3 may be connected to the device 7a or the valve 8a directly or via another connection mechanism. The joint body 3 may be connected to a flow rate measuring instrument, a pressure measuring instrument, a temperature measuring instrument, or the like, instead of the device 7a or the valve 8 a.

As shown in fig. 5, the pipe member 1 may be connected to a device 7b such as a tank as another form of the joint with a sealing member of the present invention. In addition, as shown in fig. 6, the pipe member 1 may be connected to a valve 8b (including a needle valve, a ball valve, etc.). The pipe member 1 may be integrally attached to the device 7b or the valve 8b, or the other end portion of the pipe member 1, i.e., the end portion having no flare shape, may be connected to the device 7b or the valve 8b by welding or the like directly or via another connection mechanism. The pipe member 1 may be connected to a flow rate measuring instrument, a pressure measuring instrument, a temperature measuring instrument, or the like, instead of the device 7b or the valve 8 b.

A groove 3d for accommodating the seal member 4 is preferably formed at an end of the joint main body 3 facing the pipe member 1. The groove 3d may be formed in accordance with the shape of the seal member 4, and for example, when the seal member is an O-ring, the groove 3d is annular. The depth of the groove 3d is smaller than the length of the cross section of the seal member 4 in the direction perpendicular to the surface where the joint body 3 and the pipe member 1 are joined. When the pipe member 1 is coupled to the joint body 3, the seal member 4 is sandwiched between the end surface of the flare shape portion 1a and the end surface of the male screw portion 3 a. The sealing member 4 and the groove 3d may be provided in one or more than one between the joint body 3 and the pipe member 1. The joint body 3 may be provided with the seal members 4 on a plurality of contact surfaces with the pipe member 1.

As described above, the end face of the flare shape portion 1a is preferably a flat face. The flat surface may be subjected to general surface processing, but is preferably a flat surface having fine irregularities without being subjected to mirror surface processing. The surface roughness (maximum height roughness Rz, JIS B0601: 2013) of the end face is, for example, 0.2 to 12.5, preferably 0.8 to 3.2. When the surface roughness of the end face is excessively large, leakage of fluid (leak path) is easily generated. When the surface roughness is too small, the seal surface pressure is insufficient, and an appropriate amount of grease cannot be retained.

For the joint with a sealing member of the present invention, as for a portion directly contacting hydrogen, for example, stainless steel, heat-resistant steel, aluminum alloy, or the like can be used.

In a high-pressure hydrogen atmosphere, embrittlement (hydrogen atmosphere embrittlement) by hydrogen gas may occur in stainless steel. As a stainless steel having sufficient hydrogen deterioration resistance without causing embrittlement of a hydrogen environment, which is a standard of a high-pressure gas plant of a hydrogen compression station specified by the high-pressure gas security law, SUS316 and SUS316L (JIS G4303: 2005, JIS G4304: 2010, JIS G4305: 2010) can be used at a pressure of 82MPa or less which is commonly used (stainless steel having a drawing of 75% or more in a tensile test or a factory product record (mill) and having a nickel equivalent of 28.5 or more in a case where a temperature thereof is commonly used of-45 ℃ or more and less than-10 ℃, stainless steel having a nickel equivalent of 27.4 or more in a case where a temperature thereof is commonly used of-10 ℃ or more and less than 20 ℃, and stainless steel having a nickel equivalent of 26.3 or more in a case where a temperature thereof is commonly used of 20 ℃ or more and less than 250 ℃).

Nickel equivalent (mass%) 12.6 × C +0.35 × Si +1.05 × Mn + Ni +0.65 × Cr +0.98 × Mo

Here, C represents a value (%) of the mass fraction of carbon, Si represents a value (%) of the mass fraction of silicon, Mn represents a value (%) of the mass fraction of manganese, Ni represents a value (%) of the mass fraction of nickel, Cr represents a value (%) of the mass fraction of chromium, and Mo represents a value (%) of the mass fraction of molybdenum.

For the joint with a sealing member of the present invention, as for the portion directly in contact with hydrogen, stainless steel satisfying the above-described value is preferably used.

In addition to the above, as stainless steel, for example, SUSF316(JIS G3214: 2009), SUSF316L (JIS G3214: 2009), SUS316TP (JIS G3459: 2012, JIS G4303: 2005), SUS316LTP (JIS G3459: 2012), and the like can be used. Among these stainless steels, preferred are stainless steels having a drawing of 75% or more in a tensile test or a manufacturer product record and a nickel equivalent of 28.5 or more in the case where the temperature thereof is-45 ℃ or more and less than-10 ℃ in common use, 27.4 or more in the case where the temperature thereof is-10 ℃ or more and less than 20 ℃ in common use, and 26.3 or more in the case where the temperature thereof is 20 ℃ or more and 250 ℃ or less in common use.

As the heat-resistant steel, SUH660(JIS G4311: 2011, JIS G4312: 2011) or the like can be used, for example. The heat-resistant steel is preferably subjected to solution heat treatment and aging treatment.

As the aluminum alloy, for example, A6061 PT6(JIS H4000: 2014), A6061 BET6(JIS H4040: 2015), A6061 BDT6(JIS H4040: 2015), A6061 TET6(JIS H4080: 2015), A6061 TDT6(JIS H4080: 2015), A6061 FDT6(JIS H4140: 1988), A6061 FHT6(JIS H4140: 1988), and the like can be used.

Preferably, a back up ring (back up ring) is further provided on an end surface of the joint body 3 facing the pipe member 1 so as to contact the seal member 4. From the viewpoint of preventing the sealing member 4 from being exposed, support rings may be provided on the inner and outer sides of the sealing member 4, or only on the outer side. Further, by providing a backup ring to fill a gap between the end surface of the male screw portion 3a of the joint body 3 and the end surface of the flared portion 1a of the pipe member 1, which sandwich the seal member 4, it is possible to improve the sealing property and prevent contamination and damage of the seal member. The material of the support ring is not particularly limited, and for example, fluororesin (polytetrafluoroethylene, etc.), polyamide resin (nylon 6, etc.), polyacetal resin, polycarbonate, and the like can be used. "VALFLON" and "Filler Mixed VALFLON" manufactured by Wacker industries, Japan may also be used.

For example, when assembling the joint 10 with a seal member, first, the pipe member 1 is inserted into the coupling member 5, and the engaged portion 5a is engaged with the flare-shaped portion 1a from the opposite side (right side in the drawing) of the portion of the pipe member 1 facing the joint main body 3. On the other hand, the female screw portion 3b of the joint body 3 is screwed into the male screw portion of the other pipe member 2 and fixed. Then, a proper amount of grease is applied to the groove 3d at the end of the joint body 3 and the grease applying portion 6 at the end of the pipe member 1 facing the seal member 4, and the seal member 4 is accommodated in the groove 3d (shown by an O-ring in the drawing) at the end face of the male screw portion 3a of the joint body 3. Then, the male screw portion 3a of the joint body 3 is screwed into the female screw portion 5b of the coupling member 5. In this way, the engaged portion 5a of the coupling member 5 engages with the flare-shaped portion 1a of the pipe member 1, and the male screw portion 3a of the joint body 3 fixed to the other pipe member 2 is screwed into the female screw portion 5b of the coupling member 5, whereby the pipe member 1 and the other pipe member 2 are coupled via the coupling member 5. The seal member 4 accommodated in the groove 3d is held in a compressed state by being sandwiched between the end surface of the male threaded portion 3a of the joint body 3 and the end surface of the flare-shaped portion 1a of the pipe member 1, and therefore, the sealing property of the connecting portion is good.

For example, when the pipe member 1 and the other pipe member 2 are disconnected from each other, the coupling member 5 is rotated to release the screwing of the male screw portion 3a and the female screw portion 5b of the joint body 3, and the male screw portion 3a is disengaged from the female screw portion 5 b. Next, the coupling member 5 is retracted to the opposite side (rightward in the drawing) of the portion of the pipe member 1 facing the joint main body 3. Thus, the end face of the male screw portion 3a and the end face of the flare shape portion 1a come into contact with each other but are not fixed. Therefore, by sliding the pipe member 1 in the direction B, the end surface of the male screw portion 3a and the end surface of the flare shape portion 1a are brought into a state where they do not touch each other and the hollow portions thereof are not communicated with each other. In this way, the pipe member 1 and the joint body 3 are disconnected from each other, and thus the pipe member 1 and the other pipe member 2 are disconnected from each other. When the coupling member 5 is rotated, the gripped portion 3c of the joint body 3 is gripped by a tool such as a wrench, so that the coupling member 5 alone can be rotated and loosened without simultaneously rotating the joint body 3. In this way, the presence of the gripped portion 3c makes it possible to easily hold the joint main body 3 against rotation.

< sealing Member >

The seal member is disposed between the joint main body and the pipe member, preferably, in a groove provided in the joint main body. The sealing member is formed from a crosslinked product of a rubber composition for sealing members, which contains 50 to 140 parts by mass of [ B ] silica and 10 to 50 parts by mass of [ C ] silane coupling agent per 100 parts by mass of [ A ] rubber component. Hereinafter, each component contained in the rubber composition for a sealing member of the present invention and optionally contained components will be described in detail.

[ A ] rubber component

As the rubber component, for example, there can be used: ethylene-propylene-diene rubber (EPDM), ethylene-propylene rubber (EPM), nitrile rubber (NBR; acrylonitrile butadiene rubber), hydrogenated nitrile rubber (HNBR; hydrogenated acrylonitrile butadiene rubber), butyl rubber (IIR), fluoro rubber (FKM), silicone rubber (Q), and the like. As the rubber for the sealing member, EPDM, HNBR, FKM, and the like are preferable from the viewpoint of having good properties together. The rubber component may be composed of only one kind, or may include two or more kinds.

In order to store high-pressure hydrogen, it is required to have excellent blister resistance and to be sealed even in a low-temperature environment of-40 ℃ to-85 ℃. The sealability in a low temperature environment means that, for example, hydrogen leakage does not occur even in an environment where a high-pressure hydrogen apparatus is used, particularly in a case where a sealing member is used for a high-pressure hydrogen apparatus at a temperature of-35 ℃ and a pressure of 100MPa, which is one of severe environments. Hydrogen leakage at low temperatures generally occurs due to a decrease in shape-following properties and recovery properties of the sealing member. EPDM is a rubber excellent in low temperature properties (recovery at low temperature), chemical resistance, cleaning properties, and the like, and is less expensive than NBR, HNBR, FKM, Q, and the like, and therefore is one of the rubber components suitable for use in sealing members.

EPDM is a terpolymer comprising structural units derived from ethylene, structural units derived from propylene, and structural units derived from a diene monomer. In the EPDM, the rubber characteristics can be controlled by adjusting the content ratio of the ethylene-derived structural unit to the propylene-derived structural unit. For example, when the ratio of the structural units derived from ethylene is increased, there is a tendency that the chemical resistance and crystallinity (and thus mechanical strength) of the rubber are increased. On the other hand, when the ratio of the structural units derived from ethylene is decreased, the moldability and flowability of the rubber tend to be decreased. In order to produce a molded article (sealing member) having better processability and high quality by injection molding, the flowability of the rubber component used is preferably relatively low.

From such a viewpoint, the content of the ethylene-derived structural unit in the EPDM is preferably 65 wt% or less, and more preferably 60 wt% or less. When the content of the structural unit derived from ethylene is 65% by weight or less, good flowability can be imparted to EPDM and good low-temperature properties can be imparted to the sealing member.

On the other hand, when the content of the structural unit derived from ethylene is too low, the tensile strength of the resulting sealing member is insufficient. Therefore, the content of the structural unit derived from ethylene is preferably 45% by weight or more, and more preferably 50% by weight or more.

Specific examples of the diene monomer constituting the EPDM include: non-conjugated diene monomers such as 5-ethylidene-2-norbornene (ENB), dicyclopentadiene (DCPD), 1, 4-hexadiene (1, 4-HD), methyltetrahydroindene, 5-methylene-2-norbornene, cyclooctadiene, and bicyclooctadiene. Among them, ENB and 1, 4-HD are preferably used from the viewpoint that EPDM exhibits a good crosslinking rate (vulcanization rate) and that the obtained sealing member is excellent in heat resistance, and ENB is more preferably used from the viewpoint that the crosslinking rate is particularly excellent. The diene monomer may be used alone or in combination of two or more.

The content of the diene monomer-derived structural unit in the EPDM is preferably 1 wt% or more, and more preferably 3 wt% or more, from the viewpoint of improving the crosslinking rate and the moldability of the rubber composition. In view of the ease of deterioration of the sealing member due to a large amount of double bonds remaining after crosslinking, the content of the structural unit derived from the diene monomer is preferably 12% by weight or less, more preferably 10% by weight or less.

Specific examples of commercially available products of EPDM usable in the present invention include "EPT" manufactured by Mitsui chemical Co., Ltd, "ESPRENE" manufactured by Sumitomo chemical Co., Ltd, "EP" manufactured by JSR, and "KELTAN" manufactured by LANXESS.

The viscosity of the rubber composition was measured in accordance with JIS K6300-1: the Mooney viscosity [ ML (1+4)100 ℃ C ] at 100 ℃ measured by 2013 is preferably 60 or less. When the Mooney viscosity is too high, the processability is sometimes poor. In order to realize a rubber composition having such a viscosity, the viscosity of the rubber component used is preferably 50 or less, more preferably 48 or less in terms of Mooney viscosity [ ML (1+4)100 ℃ ].

[ B ] silica

The composition for sealing member is highly filled with silica. Since hydrogen hardly enters the inside of the sealing member by highly filling silica, the blister resistance of the sealing member can be improved. Silica has lower hydrogen adsorption than carbon black and is therefore more useful for improving blister resistance.

As the silica, silica generally used as a filler which exerts a reinforcing effect in general-purpose rubbers can be used. The silica is not particularly limited, and includes: dry white carbon manufactured by a thermal decomposition method of halogenated silicic acid or an organic silicon compound, a method of oxidizing SiO air gasified by heating and reducing silica sand, or the like; wet white carbon produced by a thermal decomposition method of sodium or the like; and the like. In the present invention, dry white carbon is preferably used. Only one kind of silica may be used, or two or more kinds may be used in combination.

The silica contains at least 70% by weight of a silica component (SiO)₂). The specific surface area of the silicon dioxide is preferably 10-120 m²A concentration of 15 to 40m²/g。

The silica is preferably non-porous and spherical. When the silica is spherical, the silica can be highly filled in the rubber composition for a sealing member because the silica has less friction with each other and the dispersibility is improved as compared with silica having another shape (for example, a chain shape). Further, when a large amount of silica is contained, the low temperature property of the sealing member may be lowered, but if the silica is spherical, the lowering of the low temperature property is less likely to occur. Therefore, both the blister resistance and the low temperature property of the sealing member can be satisfied. The term "spherical" means not only a true ball but also a slightly deformed ball.

The average particle diameter of the silica is preferably 5nm to 5 μm from the viewpoints of inhibition of aggregation and smoothness. When the average particle diameter of silica is too large, the blister resistance and low temperature resistance of the sealing material may be lowered. The average particle diameter can be determined, for example, as follows: morphological observation was performed using a microscope, and the particle diameter of silica in the observation field was measured by image analysis, and the average of the measured values was calculated.

The content of silica in the rubber composition for a sealing member is 50 to 140 parts by mass, preferably 80 to 140 parts by mass, per 100 parts by mass of the rubber component. When the content of silica is excessive, the low temperature property of the sealing member may be reduced.

[ C ] silane coupling agent

The rubber composition for a sealing member of the present invention contains a silane coupling agent for highly filling silica. The silane coupling agent has a reactive group chemically bonded to the inorganic material and a reactive group chemically bonded to the organic material in a molecule, and thus functions as a binder for connecting the inorganic material and the organic material, which are generally difficult to bond. When the surface of silica is covered with a silane coupling agent, the surface of silica becomes hydrophobic, and the aggregation of silica can be prevented. This makes it possible to highly disperse silica in the rubber composition for a sealing member and to increase the blistering resistance of the sealing member. Further, the silane coupling agent increases the bonding force between the silica and the rubber component, and also improves the blister resistance.

The silane coupling agent in the present invention is not particularly limited, and examples thereof include: vinyl, acrylic, epoxy, methacrylic, mercapto, amino silane coupling agents, and the like. Examples of the vinyl silane coupling agent include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, etc., examples of the acrylic silane coupling agent include 3-acryloxypropyltrimethoxysilane, etc., examples of the epoxy silane coupling agent include 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, etc., and examples of the methacrylic silane coupling agent include 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, etc. These silane coupling agents may be used alone or in combination of two or more.

The content of the silane coupling agent in the rubber composition for a sealing member is 10 to 50 parts by mass, preferably 15 to 30 parts by mass, per 100 parts by mass of the rubber component. By containing a larger amount of the silane coupling agent than in the conventional case, the foaming resistance of the rubber composition for a sealing member is improved. However, when the silane coupling agent is too much, the elongation is extremely reduced, and therefore, there is a possibility that the product may be broken or the low-temperature property may be reduced during use.

[ D ] carbon Black

The rubber composition for a sealing member preferably further contains carbon black. By containing carbon black, the strength and blister resistance of the sealing member can be improved.

When the rubber composition for a sealing member contains carbon black, the content of carbon black may be, for example, 40 parts by mass or less, and preferably 15 to 40 parts by mass, per 100 parts by mass of the rubber component. The content of the carbon black is preferably 20 parts by mass or more from the viewpoint of keeping the co-crosslinking agent. However, since carbon black adsorbs hydrogen, when a large amount of carbon black is blended, the blister resistance may be lowered. The total content of silica and carbon black is preferably 90 to 140 parts by mass per 100 parts by mass of the rubber component. The foaming resistance is improved by highly filling a filler such as silica or carbon black, but when the amount of the filler is too large, the rigidity of the sealing member becomes too high, and the low temperature property may be lowered.

Further, the carbon black is preferably spherical. When the carbon black is closer to a true sphere (the specific surface area is small), the carbon black is less likely to aggregate, and the low-temperature property of the rubber composition for a sealing member is less likely to decrease. From the viewpoint of reinforcement, the particle size of carbon black is preferably small.

The carbon black may be conductive or nonconductive, and the following are prepared: furnace black, channel black, acetylene black, ketjen black, thermal black, lamp black, and the like.

As carbon black, for example, SAF, ISAF-HF, ISAF-LS, IISAF-HS, HAF-HS, HAF-LS, MAF, FEF-LS, GPF-HS, GPF-LS, SRF-HS, SRF-LM, FT, MT and the like can be used. The average particle diameter of carbon black may vary depending on the manufacturing company, but for example, SAF is 19nm, ISAF is 23nm, HAF is 28nm, MAF is 38nm, FEF is 43nm, GPF is 62nm, SRF is 66nm, and FT is 122 nm.

The carbon black may be used alone or in combination of two or more. The difference between the average particle diameter of the carbon black having a larger diameter and the average particle diameter of the carbon black having a smaller diameter in the two types of carbon blacks having different particle diameters is not particularly limited, and may be, for example, 7nm or more and 330nm or less.

[ E ] Co-crosslinking agent

The rubber composition for a sealing member preferably further contains a co-crosslinking agent. Examples of the co-crosslinking agent include: quinone dioxime, ethylene glycol dimethacrylate, divinylbenzene, diallyl phthalate, triallyl isocyanurate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, 1, 2-polybutadiene, metal methacrylate, metal acrylate, and the like. The co-crosslinking agent may be used alone or in combination of two or more.

The content of the co-crosslinking agent in the rubber composition for a sealing member is preferably 1 to 20 parts by mass per 100 parts by mass of the rubber component. Within this range, the blister resistance of the sealing member can be further improved. When the content of the co-crosslinking agent is too small, the 100% tensile stress of the seal member may be reduced, and when the content of the co-crosslinking agent is too large, the elongation at the time of cutting may be less than 100%, and the low temperature property may be reduced.

As the co-crosslinking agent, it is preferable to use one having a wide range of intramolecular reaction points. When a co-crosslinking agent having a wide reaction point is used, the sealing material is tightly bonded to improve mechanical strength and blister resistance while maintaining elongation. From such a viewpoint, the co-crosslinking agent preferably contains trimethylolpropane trimethacrylate.

[ F ] additives

The rubber composition for a sealing member of the present invention may contain other components than the above components as necessary. Examples of other components to be contained include: fillers other than silica and carbon black (meaning including extender pigments and coloring pigments), surfactants other than silane coupling agents, antioxidants, processing aids (stearic acid, zinc oxide, and the like), stabilizers, tackifiers, polyols, plasticizers, flame retardants, waxes, lubricants, and other additives. The additive may be used alone or in combination of two or more.

When the rubber composition for a sealing member contains the above-mentioned additive, the content thereof may be an amount generally used in this field, and is, for example, 0.5 to 15 parts by mass per 100 parts by mass of the rubber component.

Examples of the filler include alumina, zinc oxide, titanium dioxide, clay, talc, diatomaceous earth, barium sulfate, calcium carbonate, magnesium carbonate, calcium oxide, mica, graphite, aluminum hydroxide, aluminum silicate, hydrotalcite, a particulate or powdery resin, a metal powder, a glass powder, and a ceramic powder.

Examples of the antioxidant include phenol derivatives, aromatic amine derivatives, amine-ketone condensates, benzimidazole derivatives, dithiocarbamic acid derivatives, and thiourea derivatives.

Examples of the vulcanization accelerator include thiuram-based, thiazole-based, sulfenamide-based, thiourea-based, guanidine-based, and dithiocarbamate-based compounds.

Examples of the processing aid include thermoplastic resins, liquid rubbers, plasticizers, softeners, internal mold release agents, and tackifiers. For example, in the case where the rubber component is FKM or FFKM, the filler may contain a fluororesin or its particles, and the processing aid may contain a liquid fluororubber. When the rubber component is EPM or EPDM, a paraffin oil, for example, may be contained as the processing aid.

Specific examples of the internal mold release agent include higher fatty acids, fatty acid esters, fatty acid amides, fluorine resins, silicone resins, hydrocarbon resins, and the like.

Examples of the surfactant other than the silane coupling agent include nonionic surfactants, and examples of the nonionic surfactant include higher alcohols and polyhydric alcohols. Specific examples of the polyol include, for example, diethylene glycol.

Examples of the plasticizer include oils (naphthenic process oil, paraffin process oil, aromatic process oil, vegetable oil, epoxidized vegetable oil) in addition to plasticizers in a narrow sense (phthalate-based, adipate-based, aliphatic dibasic acid ester-based, phosphate-based, citrate-based, trimellitic acid-based plasticizers, etc.). From the viewpoint of blister resistance, it is preferable not to contain a plasticizer.

As the crosslinking agent, sulfur, an organic sulfur compound, a disulfide, an organic peroxide, or the like can be used. Examples of the organic peroxide used in EPDM and H-NBR include 2, 5-dimethyl-2, 5-di-tert-butyl-hexane peroxide-3, di-tert-butyl peroxide, 2, 5-dimethyl-2, 5-di-tert-butyl-hexane peroxide, tert-butylcumyl peroxide, 1, 3-bis (tert-butylperoxy-isopropyl) benzene, dicumyl peroxide, 4-di-tert-butylperoxy-butyl valerate, 2-di-tert-butylperoxy-butane, 1-di-tert-butylperoxy-3, 3, 5-trimethylcyclohexane, dibenzoyl peroxide, bis (o-methylbenzoyl) peroxide, bis (p-methylbenzoyl) peroxide, and tert-butylperoxy-benzilate.

The content of the crosslinking agent in the rubber composition for a sealing member is usually 0.1 to 10 parts by mass, preferably 0.2 to 5.0 parts by mass, per 100 parts by mass of the rubber component. Within this range, the crosslinking reaction can be sufficiently advanced, and thus a cushioning material having excellent impact resistance and excellent hardness, mechanical strength, compression set resistance, and the like can be obtained.

[ method for producing sealing Member ]

The crosslinkable rubber composition of the present invention can be prepared by uniformly kneading the above-mentioned components. As the kneading machine, a conventionally known kneading machine such as a mixing roll (kneading roll), a pressure kneader, and an internal mixer (banbury mixer) can be used. In this case, components other than the components contributing to the crosslinking reaction (crosslinking accelerator, crosslinking retarder, crosslinking agent, etc.) among the compounding components may be uniformly kneaded in advance, and then the components contributing to the crosslinking reaction may be kneaded. The kneading temperature is, for example, around room temperature.

The sealing member used in the present invention is formed of a crosslinked product of the rubber composition for a sealing member. The sealing member can be produced by crosslinking (vulcanizing)/molding a rubber composition for a sealing member. The crosslinking/molding method may be a conventionally known method such as injection molding, compression molding, transfer molding, or the like.

The heating temperature (crosslinking temperature) during molding is, for example, about 100 to 200 ℃, and the heating time (crosslinking time) during pressing is, for example, about 5 to 30 minutes. In the case of HNBR, EPDM, CR, FKM, VMQ, preferably two vulcanization.

The sealing member 4 may be a packing, a washer (gasket), or the like. The shape of the sealing member may be appropriately selected according to the purpose, and a representative example thereof is an O-ring having an O-shape in cross section. The sealing member of the present invention is excellent in low-temperature characteristics and blistering resistance, and therefore can be suitably used as a sealing member for a storage tank for storing high-pressure hydrogen gas at 80MPa, for example. The high-pressure gas to be stored is not only hydrogen but also oxygen, nitrogen, helium, or the like.

< lubricating grease >

Grease is applied to the surfaces of the joint main body 3 and the pipe member 1 facing the respective ends of the seal member, and preferably to the surface of the male threaded portion 3a of the joint main body 3 facing the end of the seal member 4 and the surface of the flared shape portion 1a of the pipe member 1 facing the end of the seal member 4. More preferably, as shown in fig. 8, the grease coating portion 6 on the surface of the groove 3d of the joint main body 3 and the grease coating portion 6 of the flare shape portion 1a are coated with grease.

In order to improve the workability and to uniformly apply the grease, the grease may be processed (for example, diluted, heated, etc.) and then used. To eliminate coating unevenness, the coating may be repeated several times. The amount of grease applied may be, for example, about 0.1 to 5g per P6(JISB 2401-1: 2012) O-ring groove.

The grease fills the irregularities on the surface of the flare shape portion 1a of the pipe member 1, thereby improving the sealing property particularly at low temperatures. Further, the fluidity of the sealing member 4 in the groove 3d can be improved, and the following property of the O-ring can be improved.

The grease used in the present invention is preferably a grease having a high kinematic viscosity. A high kinematic viscosity means, for example, a kinematic viscosity at 25 ℃ of from 6000 to 100 ten thousand cSt (Centi Stokes, mm)²S), preferably 1.5 to 100 ten thousand cSt, more preferably 5 to 100 ten thousand cSt. If the kinematic viscosity of the grease is too low, the grease may not remain on the end surface of the flare shape portion 1a and may flow out. The grease having a high kinematic viscosity is less likely to volatilize even in a high-temperature environment, and is excellent in durability against pressure fluctuations.

The type of grease used in the present invention is not particularly limited, and known greases such as animal oil, vegetable oil, mineral oil, and synthetic oil can be used. Examples of the animal oil include whale oil, beef tallow, squalane oil, and lard. Examples of the vegetable oil include rapeseed oil, safflower oil, soybean oil, sesame oil, castor oil, camellia oil, and rice bran oil. Examples of the mineral oil include aromatic hydrocarbons, paraffin hydrocarbons, and naphthene hydrocarbons. Examples of the synthetic oil include silicone oil, fluorine oil, synthetic hydrocarbon oil, ester oil, polyether oil, polyethylene glycol oil (polyglycol oil), and phenylene ether oil. These greases may be used alone or in combination of two or more.

Examples of the silicone oil include dimethyl silicone oil, methylphenyl silicone oil, and methyl hydrogen-containing silicone oil, and examples of the modified silicone oil include fluorine-modified, epoxy-modified, alcohol-modified, alkyl-modified, amino-modified, methacryl-modified, mercapto-modified, hydrogen-modified, and carboxyl-modified silicone oils. Commercially available silicone oils include, for example, those having the product names "KF-96", "KF-965", "KF-968", "KF-99", "KF-50", "KF-54", "HIVAC F-4", "HIVAC F-5", "KF-56A", "KF-995", "KF-868", "KF-859" (manufactured by shin-Etsu chemical Co., Ltd.), "SH 200" (manufactured by Toto Corning Co., Ltd.).

Examples of the fluorine oil include perfluoropolyether, chlorotrifluoroethylene, perfluoroalkyl ether, and the like. Examples of commercially available products of the fluorine oil include "KRYTOX (registered trademark) GPL 102" (manufactured by Chemours corporation), "DAIFLOIL (registered trademark) # 1", "DAIFLOIL # 3", "DAIFLOIL # 10", "DAIFLOIL # 20", "DAIFLOIL # 50", "DAIFLOIL # 100" and "DEMNUM (registered trademark) S-65" (manufactured by Dajin Industrial Co., Ltd.).

Examples of the synthetic hydrocarbon oil include poly α -olefin, ethylene- α -olefin co-oligomer, polybutene or a hydrogenated product thereof, alkylbenzene, and alkylnaphthalene.

From the viewpoint of obtaining good sealing properties at low temperatures, it is preferable to use a grease whose kinematic viscosity is less likely to change due to temperature changes. Examples of such a grease include silicone oil and fluorine oil. At low temperatures, rubber tends to lose its elasticity and to deteriorate its sealing properties, but the lubricating properties of grease can be maintained at low temperatures.

Further, grease containing the above oil as a base oil and a thickener may be used. The thickener is not particularly limited, and a metal soap-based thickener or a non-soap-based thickener can be used. Examples of the metal soap-based thickener include calcium soap, sodium soap, lithium soap, aluminum soap, calcium complex soap, barium complex soap, lithium complex soap, and aluminum complex soap. Examples of the non-soap thickener include urea, sodium terephthalate, fluorine, organobentonite, and silica. These thickeners may be used singly or in combination of two or more.

The blending ratio of the base oil and the thickener is not particularly limited, and may be arbitrarily determined in order to obtain a desired grease hardness. The amount of the thickener is, for example, 1 to 50 parts by mass, preferably 5 to 30 parts by mass, per 100 parts by mass of the grease. The amount of the base oil is, for example, 50 to 99 parts by mass, preferably 70 to 95 parts by mass, based on 100 parts by mass of the grease. The adjustment can be made by reducing the proportion of the base oil in order to harden the grease hardness, and the adjustment can be made by increasing the proportion of the base oil in order to soften the grease hardness.

When a thickener is added, the kinematic viscosity of the base oil at 40 ℃ is, for example, 10 to 5000mm²Preferably 20 to 500 mm/s²(ii) s, more preferably 30 to 200mm²/s。

In addition, various additives generally used in the field of lubricating oil and grease, for example, an antioxidant, an anticorrosive agent, an antirust agent, a friction and wear resistant additive, an extreme pressure additive, an oiliness agent, a solid lubricant, and the like may be added to the grease as needed.

The mixing consistency of the grease is not particularly limited, but is preferably 175 to 370, more preferably 220 to 290, and the consistency number is, for example, No. 1 to No. 4, preferably No. 2 to No. 3. The mixing consistency of the grease may be according to JIS K2220.7: 2013 for measurement.

The mixing stability of the grease is not particularly limited, and is, for example, 330 to 400. The mixing stability of the grease may be measured according to JIS K2220.7: 2013 for measurement.

[ examples ]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto.

[ preparation of rubber composition for sealing Member and production of sealing Member ]

The rubber composition for a seal member was prepared as follows. First, the rubber component was kneaded. The rotation speed was 35rpm and the time was 1 minute. Silica was coated with a silane coupling agent in accordance with the compounding composition shown in table 1 (the unit of the compounding amount in the table is part by mass). The covering silica, the rubber component, the antioxidant, the processing aid and the surfactant were kneaded by a pressure kneader. At this time, the rotation speed of the pressure kneader was 35rpm, and the kneading time was 3 minutes. Next, carbon black and a co-crosslinking agent were added and mixed at 35rpm for 6 minutes. After cooling to about 40 ℃, the crosslinking agent was added to the obtained kneaded mixture, and the kneaded mixture was kneaded by a pressure kneader to prepare a rubber composition for a sealing member. The obtained rubber composition for sealing members is press-molded at a temperature of 170 to 180 ℃ and subjected to secondary vulcanization at 180 ℃ for 1 hour to obtain sealing members 1 to 4.

[ Table 1]

TABLE 1. Compulsory watch

The details of the complexes in table 1 are as follows.

Rubber component [1 ]: E501A (product of Sumitomo chemical industries, Ltd. "ESPRENE", EPDM: the content of structural units derived from ethylene is 52% by weight, the content of structural units derived from 5-ethylidene-2-norbornene (ENB) as a diene monomer is 4% by weight, and the Mooney viscosity at 100 [ [ ML (1+4)100 ℃ ] ] measured according to JIS K6300-1: 2013 is 40.)

[2] silica: SUNSPHERE NP-30 (manufactured by AGC SI-TECH Co., Ltd., spherical non-porous silica, adsorption specific surface area 40 m)²G, pore volume 0.05mL/g, oil absorption 30mL/100g, average particle diameter 4 μm)

[3] silane coupling agent: KBM1003 (manufactured by shin-Etsu chemical Co., Ltd., vinyltrimethoxysilane)

[4] carbon Black: MT (spherical, average particle diameter of 250-350 nm, manufactured by Cancarb corporation)

[5] processing aid 1: LUNAC S50V (stearic acid, King of flower Co., Ltd.)

[6] antiaging agent 1: NONFLEX RD (Poly (2, 2, 4-trimethyl-1, 2-dihydroquinoline, manufactured by Seiko chemical Co., Ltd.)

[7] processing aid 2: made Sakai #20 (made by Sakai chemical Co., Ltd., Zinc oxide)

[8] surfactant: diethylene glycol (manufactured by Japan catalyst of Kabushiki Kaisha)

[9] Co-crosslinking agent: TAIC (triallyl isocyanurate manufactured by Nippon Kasei Co., Ltd.)

[ 10 ] crosslinking agent: perbutyl P (manufactured by Nichii oil Co., Ltd., 1, 3-bis (t-butylperoxyisopropyl) benzene)

[ evaluation of blister resistance of sealing member ]

The seal members 1 to 4 molded into O-rings were tested for blister resistance under the conditions shown in table 2. Fig. 9 shows a test process diagram. After the test, the cross section of the O-ring was observed, and the sealing member in which cracks were observed was evaluated as "B", and the sealing member in which cracks were not observed was evaluated as "a". The evaluation results are shown in table 1.

[ Table 2]

TABLE 2 test conditions

As shown in table 1, the sealing

members

1, 2 have good blister resistance. On the other hand, the sealing

members

3 and 4 have cracks in the cross section of the O-ring, and do not have sufficient blister resistance.

The same blistering resistance test as described above was also performed for commercial products, product number B5690 (HNBR for freon (R134a)), product number B5485 (HNBR for freon (R134a)), H0870 (EPDM for steam, chemical and brake oil), and H0880 (EPDM for hot water and steam) (above, manufactured by hualca corporation), but cracks were observed in the cross section of the O-ring.

[ evaluation of physical Properties of sealing Member ]

Next, the physical properties of the sealing member were measured. From JIS K6250: 2006 sheet-like molded article having a thickness of 2mm, according to JIS K6251: 2017 and demolding to obtain the dumbbell-shaped test piece of the size 3. The test piece was stretched at 500 mm/min, and the tensile strength, elongation at cut and 100% tensile stress were measured using a Shopper type tensile tester. In addition, according to JIS K6253: 2012, the hardness of the sheet-like molded article was measured by a type A durometer hardness tester. All of these tests were carried out at a temperature of 25 ℃. Further, the reaction was carried out in accordance with JIS K6261-4: 2017, TR10 was determined by the low-temperature elastic recovery test. The results are shown in Table 3.

[ Table 3]

TABLE 3 physical Properties of sealing Member

Consider that: the

seal members

1 and 2 have higher hardness than the

seal members

3 and 4 and higher 100% tensile stress, and therefore have high strength against initial cracking, that is, high resistance against foaming. When comparing the values of TR10 for seal member 1 and seal member 2, it is known that: the sealing member 1 has a value lower than that of the sealing member 2, and can maintain elasticity at a lower temperature.

(example 1)

Using the sealing member 1 having obtained good results in the above-described physical property evaluations, a joint with a sealing member was produced as follows. First, a pipe member is inserted into the nut, and the pipe member is connected to a test device through which a fluid flows. The engaged portion of the connecting member is engaged with the flange-shaped portion from the opposite side of the portion of the pipe member facing the joint main body. On the other hand, the other pipe member is connected to the testing device, and the female screw portion of the joint body is screwed into the male screw portion of the other pipe member and fixed. Next, as shown in table 4, grease was applied to the grooves facing the end surface of the joint body of the seal member and the grease-applied portions of the end surfaces of the pipe members. The sealing member 1 is accommodated in a groove in an end surface of the male screw portion of the joint body, and then the male screw portion of the joint body is screwed into the female screw portion of the nut, thereby connecting the joint with the sealing member.

(example 2)

Joints with sealing members were produced in the same manner as in example 1, except that the amount of grease applied was as shown in table 4.

Comparative example 1

A joint with a sealing member was produced in the same manner as in example 1, except that no grease was applied.

[ Table 4]

TABLE 4 relationship between coating amount of grease and sealing property

	Coating amount of grease	Sealing property
			Example 1	About 10 times (slightly thick and uniformly coated)	a
Example 2	Coating 1 time (thin and uniform)	b
			Comparative example 1	Is not coated with	c

The types of lubricating grease are as follows: xinyue Silicone KF-96H-100 WancSt (product of Xinyue chemical industry Co., Ltd.)

[ evaluation of leakage at Low temperature of joints with sealing members based on grease coating ]

Using the joints with sealing members of examples 1 and 2 and comparative example 1, the sealability at low temperatures was evaluated under the conditions shown in table 5. Fig. 10 shows a test process diagram. The test apparatus was filled with a fluid (helium) to confirm the presence or absence of an external leak of the fluid. The leakage of the test fluid was detected by sniffing using a helium sensor. The leak tightness of the joint in which no fluid leakage was detected was designated as "a", the leak tightness of the joint in which no fluid leakage was detected was designated as "b", and the leak tightness of the joint in which more than 120ppm of fluid was observed was designated as "c". The evaluation results are shown in table 4. Consider that: if the evaluation is "a" or "b", the high-pressure gas can be sufficiently sealed.

[ Table 5]

TABLE 5 test conditions

As shown in table 4, by applying grease, leakage (leak) of fluid from the joint with the sealing member was significantly suppressed. Further, it was found that the joint with a sealing member of the present invention can exhibit excellent sealing properties in a low-temperature environment of-40 ℃ by repeating the application of grease several times and reducing the fluid leakage to a detection limit or less.

[ test for blister resistance and Low temperature Property of Joint with sealing Member ]

Next, using the joint with a sealing member of example 1, blistering resistance and low temperature resistance tests were performed under the conditions shown in table 6. Fig. 11 shows a test process diagram. It should be noted that the following operations are repeated 10 times: the grease was diluted 1: 1 with hexane and applied uniformly to the grease application part, and then hexane was volatilized. The test apparatus was filled with a fluid (hydrogen) to confirm the presence or absence of an external leak of the fluid. The leakage of the test fluid was detected by sniffing using a hydrogen sensor. The joints in which no leakage of the fluid is sensed are set to have a sealability "a", and the joints in which leakage of the fluid is sensed are set to have a sealability "B". The evaluation results are shown in table 7.

[ Table 6]

TABLE 6 test conditions

[ Table 7]

TABLE 7 tightness test of pipe joints with sealing members

	Example 1
		Resistance to blistering (crack or not)	-
Hydrogen 6600 cycles at 100 deg.C and 100MPa	A
		Hydrogen 6600 cycles at-40 deg.C x 100MPa	A
Tightness (with or without leakage)	-
		Hydrogen 6600 cycles at 100 deg.C and 100MPa	A
Hydrogen 6600 cycles at-40 deg.C x 100MPa	A

As shown in Table 7, the joint with a sealing member of example 1 was able to seal 6600 times with 100MPa of hydrogen at 100 ℃ and-40 ℃. Foaming is more likely to occur at high temperatures, but even if 6600 times of rapid pressurization and depressurization with 100MPa of hydrogen addition are repeated, foaming is not observed in the O-ring, and no leak path is generated. In addition, even if 6600 times of the addition of 100MPa of hydrogen to the rapid pressurization and depressurization was repeated at-40 ℃, no leakage of the fluid was sensed. Therefore, the following steps are carried out: the joint with a sealing member of the present invention has characteristics of opposite blistering resistance and low temperature resistance, can be used in a wide range of environments of-40 ℃ to 100 ℃, and has good sealing performance at high temperature and low temperature.

Claims

1. A joint with a sealing member, characterized in that,

the disclosed device is provided with: a hollow joint body, a hollow pipe member having a flared end at one end, a coupling member for coupling the joint body and the pipe member, a seal member disposed between the joint body and the pipe member, and grease applied to surfaces of the joint body and the pipe member facing the respective ends of the seal member,

the sealing member is formed from a crosslinked product of a rubber composition for a sealing member, which contains 50 to 140 parts by mass of silica and 10 to 50 parts by mass of a silane coupling agent per 100 parts by mass of a rubber component.

2. The joint with sealing member according to claim 1,

the flared shape is a conical shape or a flange shape.

3. The joint with sealing member according to claim 1,

the fitting body has a groove for receiving the sealing member.

4. The joint with sealing member according to claim 1,

the fitting body also has a configuration for connection with other pipe members.

5. The joint with sealing member according to claim 1,

the sealing member further contains 40 parts by mass or less of carbon black per 100 parts by mass of the rubber component.

6. The joint with sealing member according to claim 1,

the rubber component is an ethylene-propylene-diene rubber.

7. The joint with sealing member according to claim 1,

the kinematic viscosity of the grease at 25 ℃ is 6000cSt to 100 ten thousand cSt.

8. The joint with seal member according to any one of claims 1 to 7,

the sealing member is an O-ring.

9. The joint with a sealing member according to claim 8,

further comprises a support ring.