JP5334409B2 - Rubber composition and use thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber composition having excellent sealability, heat resistance and acid resistance, and low reaction force, low hardness and small compression set, and capable of producing a molded product being improved in compression set and compression crack performance especially at a high temperature, and its application, as well as to provide a body mounting the product using the rubber composition. <P>SOLUTION: This rubber composition comprises a specific ethylene-&alpha;-olefin- nonconjugated polyene copolymer [A], carbon black [B], and a surface-modified silica [C] that is prepared by the surface modification of sedimentation silica, and has a BET specific surface area of 30-80 m<SP>2</SP>/g, a particle size of 1.0-4.0 &mu;m according to the coulter counter method, and a M value of &ge;50. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

The present invention relates to a rubber composition and use thereof. Specifically, the present invention provides a fuel cell sealing member, obtained from LIM various gasket materials, such as molding the gasket material, a rubber composition can be suitably used in applications such as for electric wire connector sealing member, and the rubber composition The present invention relates to a fuel cell seal material, a hard disk drive top cover gasket, a LIM molding gasket material, a wire connector seal material, and a main body on which they are mounted.

  Seal parts and gasket parts used in electrical appliances, etc. have excellent barrier properties, sealability, etc., satisfy desired hardness, and have high heat resistance that can cope with heat generation during energization, even in low temperature environments It is important that it can be used.

  For example, the fuel cell is the reverse reaction of water electrolysis, that is, an efficient and clean power generation system that directly extracts electricity by chemically reacting hydrogen and oxygen, and has attracted attention as a new energy system for automobiles and homes. ing. As cell seal materials for fuel cells, low-cost materials with excellent heat resistance, acid resistance, gas permeation resistance, and high-speed moldability are required. Currently, fluoro rubber is used for heat resistance and acid resistance. However, butyl rubber is used for gas permeation resistance, and silicone rubber is used for heat resistance and moldability. However, ordinary millable silicone rubber materials are not sufficient for high-speed moldability requirements. In this case, a method using liquid silicone rubber and applying LIM (Liquid Injection Molding) molding is applied. However, although silicone rubber is excellent in heat resistance and high-speed moldability, it cannot be said that acid resistance and gas permeation resistance are sufficient.

  Further, in the fuel cell, it has been studied to increase the power generation reaction temperature with the aim of further improving the power generation performance, and further high temperature durability is required for the sealing material (gasket material).

  On the other hand, electronic device products are required to be smaller and thinner as components become smaller and have higher performance. However, if the component parts are made smaller, the assembly workability of the manufacturing is deteriorated, so that integration and combination of various parts are required.

  For example, a gasket for a hard disk drive, which is an electronic storage device, may be used as a single piece of rubber, a foamed urethane sheet, and a metal cover such as stainless steel or aluminum, which are joined together with an adhesive. However, since the weight and thickness of the metal cover are reduced at the same time as the integration, there is a problem that the cover is deformed if the gasket has a high hardness (reaction force).

  Therefore, a styrene thermoplastic elastomer has been proposed as a gasket material (Patent Document 1). Styrenic thermoplastic elastomers have low hardness and do not require a vulcanization step as compared with rubber materials, and therefore, it has been shown that the process can be simplified and can be recycled.

  However, heat generation due to high performance (high rotation speed) of hard disk drives and adoption in automobiles tend to increase use in high temperature environments such as 80 ° C. or higher. Under such circumstances, there has been a problem of permanent deformation at high temperature, which is one of the mechanical properties of styrene-based thermoplastic elastomers, and there has been a limit in performance. For this reason, the appearance of a gasket material that is superior in durability at high temperatures, has low hardness, has a low compression set, and can provide a sealing property with low reaction force even at high compression is desired.

  An electric wire connector connects and branches electric wires, and is composed of a pair of male and female resin frames, electric wires, and a seal material that can be connected with one touch. The sealing material is mainly used as a dust seal between the electric wire and the resin frame. Sealing materials for wire connectors used for this type of application are required to have sealing properties and insertion properties for thin wires. Conventionally, oil bleed-type silicone rubber and nitrile rubber have been used. The rubber mainly contains silicone oil as a plasticizer, and the plasticizer adheres to the electrical contact during use, and there is a problem that a problem of energization occurs due to insulation of the electrical contact.

  Under such circumstances, Patent Document 2 describes excellent high-speed molding, excellent heat resistance, acid resistance and gas permeation resistance, fuel cell seal materials, gasket materials for electronic devices such as hard disk drives, and seal materials for electric wire connectors. A rubber composition that can be suitably used for the above has been proposed. This rubber composition is a liquid rubber composition capable of LIM molding, and since a molded product having a low hardness is obtained, a sealing material for a fuel cell or a hard disk drive that requires a low reaction force seal even at high compression. It is suitable for the gasket material. However, moldings such as gaskets and seal parts are required to have higher temperature durability, and not only compression set at high temperatures but also compression cracking at high temperatures and high strains is desired. It was rare. However, since such a rubber composition is inferior in elasticity recovery rate under a low temperature environment as compared with silicone rubber or the like, further improvement in mechanical properties under a low temperature environment has been demanded.

Moreover, as a stationary fuel cell sealing material for home use, it is 80 at 90 ° C. for 40,000 hours.
% Of compression set was required, but since the compression set rate suddenly deteriorated from 5,000 hours to 10,000 hours, the compression set rate at high temperature and long term was further improved. There has been a strong need for a rubber composition.
Japanese Patent No. 2961068 International Publication WO03 / 057777

  The present invention is excellent in sealability, heat resistance, acid resistance, and high-speed moldability, has low hardness and low reaction force, contributes to sealability in a low temperature environment, and crackability under high compression It is an object of the present invention to provide a rubber composition capable of producing a molded article having improved compression set, particularly improved compression set at a high temperature over a long period of time, its use, and a body mounted with the rubber composition.

The rubber composition of the present invention is
An ethylene / α-olefin / non-conjugated polyene copolymer [A] satisfying the following (a) to (e):
(A) a copolymer of ethylene, α-olefin, and non-conjugated polyene;
(B) the α-olefin has 3 to 20 carbon atoms,
(C) The weight ratio of ethylene unit / α-olefin unit is 35/65 to 95/5,
(D) the iodine value is in the range of 0.5-50,
(E) The intrinsic viscosity [η] measured in a decalin solution at 135 ° C. is 0.01 to 5.0 dl / g;
Iodine adsorption of not more than 80 mg / g, an average particle diameter of at 250nm or less, and the carbon black [B] DBP absorption is 10~300cm ³ / 100g,
The BET specific surface area obtained by surface modification of precipitated silica is 30 to 80 m ² / g,
It is characterized by containing surface-modified silica [C] having a particle diameter of 1.0 to 4.0 μm by a Coulter counter method and an M value of 50 or more.

In such a rubber composition of the present invention, the ethylene / α-olefin / nonconjugated polyene copolymer [A] preferably further satisfies the following (f);
(F) The non-conjugated polyene is at least one norbornene compound represented by the following general formula [I].

(In the formula [I], n is an integer of 0 to 10, and R ¹ is a hydrogen atom or a carbon atom having 1 to 1 carbon atoms.
0 is an alkyl group, and R ² is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. )
The rubber composition of the present invention comprises carbon black [B] with respect to 100 parts by weight of the total amount of the ethylene / α-olefin / non-conjugated polyene copolymer [A] and other resin components constituting the rubber composition. 1 to 40 parts by weight and 20 to 60 parts by weight of surface-modified silica [C] are preferably contained.

In the rubber composition of the present invention, the resin component in the rubber composition is preferably only an ethylene / α-olefin / non-conjugated polyene copolymer [A].
In the rubber composition of the present invention, carbon black [B] is iodine adsorption amount 15~40mg / g, an average particle diameter of 40 to 100 nm, DBP absorption amount is preferably satisfies the 40~150cm ³ / 100g.

The rubber composition of the present invention preferably further contains a crosslinking agent [D].
When the rubber composition of the present invention contains a crosslinking agent [D], the crosslinking agent [D] is represented by the following general formula [II], and the SiH group-containing compound having two SiH groups in one molecule (1 ) Is preferably included.

(In the formula [II], R ³ is a monovalent group having 1 to 10 carbon atoms, an unsubstituted or substituted saturated hydrocarbon group or an aromatic hydrocarbon group, and may be the same or different in one molecule, a is an integer of 0 to 20, b is an integer of 0 to 20, and R ⁴ is a divalent organic group having 1 to 30 carbon atoms or an oxygen atom.)
When the rubber composition of the present invention contains a crosslinking agent [D], the crosslinking agent [D] is represented by the following general formula [III] and contains a SiH group-containing compound having three SiH groups in one molecule ( 2) is also preferably included.

(In the formula [III], R ⁵ is a monovalent group having 1 to 10 carbon atoms, and is an unsubstituted or substituted saturated hydrocarbon group or aromatic hydrocarbon group, which may be the same or different in one molecule, a, b and c are each independently an integer of 0 to 20, and R ⁶ is a trivalent organic group having 1 to 30 carbon atoms.)
When the rubber composition of the present invention contains the SiH group-containing compound (1) having two SiH groups in one molecule, the ethylene / α-olefin / non-conjugated polyene copolymer [A] and the rubber composition It may contain 3.0 to 7.0 parts by weight of the SiH group-containing compound (1) having two SiH groups in one molecule with respect to 100 parts by weight of the total amount with other resin components constituting the product. preferable.

  When the rubber composition of the present invention contains the SiH group-containing compound (2) having three SiH groups in one molecule, the rubber composition with the ethylene / α-olefin / non-conjugated polyene copolymer [A] 0.1 to 2.0 parts by weight of SiH group-containing compound (2) having three SiH groups in one molecule is contained with respect to 100 parts by weight of the total amount with other resin components constituting the product. preferable.

The fuel cell sealing material of the present invention comprises the rubber composition of the present invention.
The fuel cell of the present invention has a fuel cell sealing material comprising the rubber composition of the present invention.
The hard disk drive top cover gasket of the present invention and the gasket material for LIM molding of the present invention comprise the rubber composition of the present invention.

The hard disk drive of the present invention has a hard disk drive top cover gasket made of the rubber composition of the present invention.
Electric wire connector sealing member of the present invention, the rubber composition of the present invention.

The electric wire connector of this invention has the sealing material for electric wire connectors which consists of a rubber composition of the said this invention. The electric wire connector of the present invention is preferably an automobile electric wire connector.

The rubber composition of the present invention is suitable for LIM molding, and a molded product molded using the rubber composition is excellent in sealing property, heat resistance, acid resistance, low reaction force, low hardness and low temperature environment. In addition to being excellent in low-temperature recoverability that contributes to sealing performance at low temperature, compression set at high temperatures is small over a long period of time, and excellent in compression recovery. The rubber composition of the present invention does not produce oil bleed or bloom, and can produce a molded product having excellent mechanical properties and outgas resistance. When a wire connector seal is molded, the sealing property of the wire It has excellent insertability and is suitable for a fuel cell sealing material, a LIM molding gasket material, and a wire connector sealing material. The fuel cell, hard disk drive top cover gasket, hard disk drive, electric wire connector and the like of the present invention have a molded body made of the rubber composition of the present invention, and the molded body has excellent sealing properties, heat resistance and acid resistance. It has a low reaction force and a low hardness, has a small compression set particularly under high temperature conditions, and is excellent in compression recovery.

Hereinafter, the present invention will be specifically described.
<Rubber composition>
The rubber composition of the present invention contains a specific ethylene / α-olefin / non-conjugated polyene copolymer [A], carbon black [B] and surface-modified silica [C] as essential components, and further if necessary. Containing a crosslinking agent [D].

[A] Ethylene / α-olefin / Nonconjugated Polyene Copolymer The copolymer [A] used in the present invention satisfies the following (a) to (e), preferably the following (a) to ( f) is satisfied.
(A) a copolymer of ethylene, α-olefin, and non-conjugated polyene;
(B) the α-olefin has 3 to 20 carbon atoms,
(C) The weight ratio of ethylene unit / α-olefin unit is 35/65 to 95/5,
(D) the iodine value is in the range of 0.5-50,
(E) The intrinsic viscosity [η] measured in a decalin solution at 135 ° C. is 0.01 to 5.0 dl / g,
(F) The non-conjugated polyene is at least one norbornene compound represented by the above general formula [I].

The copolymer [A] according to the present invention is a copolymer of ethylene, an α-olefin having 3 to 20 carbon atoms, and a non-conjugated polyene, and preferably a random copolymer thereof.
-Α-olefin The α-olefin constituting the copolymer [A] is an α-olefin having 3 to 20 carbon atoms. Specifically, propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-nonadecene, 1-eicocene, 9-methyl-1-decene, 11-methyl-1-dodecene, 12-ethyl-1-tetradecene, etc. Can be mentioned. Among these, α-olefins having 3 to 10 carbon atoms are more preferable, and propylene, 1-butene, 1-hexene and 1-octene are most preferably used. These α-olefins may be used alone or in combination of two or more.

Non-conjugated polyene The non-conjugated polyene constituting the copolymer [A] is not particularly limited, but is preferably a non-conjugated diene, more preferably at least one represented by the following general formula [I] The norbornene compound.

(In the formula [I], n is an integer of 0 to 10, and R ¹ is a hydrogen atom or a carbon atom having 1 to 1 carbon atoms.
0 is an alkyl group, and R ² is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. )
Specific examples of the norbornene compound represented by the general formula [I] include 5-vinyl-2-norbornene, 5- (2-propenyl) -2-norbornene, 5- (3-butenyl) -2-norbornene, 5- (1-methyl-2-propenyl) -2-norbornene, 5- (4-pentenyl) -2-norbornene, 5- (1-methyl-3-butenyl) -2-norbornene, 5- (5-hexenyl)- 2-norbornene, 5- (1-methyl-4-pentenyl) -2-norbornene, 5- (2,3-dimethyl-3-butenyl) -2-norbornene, 5-
(2-ethyl-3-butenyl) -2-norbornene, 5- (6-heptenyl) -2-norbornene, 5- (3-methyl-5-hexenyl) -2-norbornene, 5- (3,4-dimethyl) -4-pentenyl) -2-norbornene, 5- (3-ethyl-4-pentenyl) -2-norbornene, 5- (7-octenyl) -2-norbornene, 5- (2-methyl-6-heptenyl)- 2-norbornene, 5- (1,2-dimethyl-5-hexesyl) -2-
Examples include norbornene, 5- (5-ethyl-5-hexenyl) -2-norbornene, and 5- (1,2,3-trimethyl-4-pentenyl) -2-norbornene.

  Among these, 5-vinyl-2-norbornene, 5- (2-propenyl) -2-norbornene, 5- (3-butenyl) -2-norbornene, 5- (4-pentenyl) -2-norbornene, 5- (5-hexenyl) -2-norbornene, 5- (6-heptenyl) -2-norbornene, and 5- (7-octenyl) -2-norbornene are preferred. These norbornene compounds can be used alone or in combination of two or more.

  The non-conjugated polyene constituting the copolymer [A] of the present invention may be a non-conjugated polyene other than the norbornene compound represented by the above general formula [I]. The non-conjugated polyene that can be used is not particularly limited, and examples thereof include the following chain non-conjugated dienes, alicyclic non-conjugated dienes, and triene compounds, which are used alone or in combination of two or more. be able to. Moreover, non-conjugated polyenes other than the norbornene compound represented by the general formula [I] may be used together with the norbornene compound represented by the general formula [I].

  Specific examples of the chain non-conjugated diene include 1,4-hexadiene, 3-methyl-1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 4,5 -Dimethyl-1,4-hexadiene, 7-methyl-1,6-octadiene and the like.

  Specific examples of the cyclic non-conjugated diene include 5-methylene-2-norbornene, 1-methyl-5-methylene-2-norbornene, 1-ethyl-5-methylene-2-norbornene, 5-ethylidene-2-norbornene, Examples include 5-isopropylidene-2-norbornene, 5-vinylidene-2-norbornene, 6-chloromethyl-5-isopropenyl-2-norbornene, dicyclopentadiene, and methyltetrahydroindene.

  Specific examples other than the above include trienes such as 2,3-diisopropylidene-5-norbornene, 2-ethylidene-3-isopropylidene-5-norbornene, 2-propenyl-2,2-norbornadiene, and the like. .

-Composition and properties of copolymer [A] The copolymer [A] according to the present invention has an ethylene unit / α-olefin unit ratio of 35/65 to 95/5 by weight, preferably 40. / 60 to 90/10, more preferably 45/55 to 85/15, and particularly preferably 50/50 to 80/20.

When this weight ratio is within the above range, a rubber composition capable of providing a crosslinked rubber molded article having excellent heat aging resistance, strength characteristics and rubber elasticity, as well as excellent cold resistance and processability can be obtained.
The iodine value of the copolymer [A] of the present invention is 0.5 to 50 (g / 100 g), preferably 1 to 45, more preferably 1 to 43, and particularly preferably 3 to 40 (g / 100 g).

  When the element value is within the above range, a rubber composition having high crosslinking efficiency is obtained, and a crosslinked rubber molded article having excellent compression set resistance and environmental degradation resistance (= heat aging resistance). Can be obtained. If the iodine value exceeds the above range, the crosslink density becomes too high, and mechanical properties such as tensile elongation may deteriorate.

  The intrinsic viscosity [η] measured in 135 ° C. decalin of the copolymer [A] according to the present invention is 0.01 to 5.0 dl / g, preferably 0.03 to 4.0 dl / g, Preferably it is 0.05-3.5 dl / g, Most preferably, it is 0.07-3.0 dl / g. Further, an embodiment in which the intrinsic viscosity [η] of the copolymer [A] is 0.5 dl / g or less, preferably less than 0.3 dl / g, is particularly suitable when the rubber composition is LIM-molded. When the intrinsic viscosity [η] is within the above range, a rubber composition capable of providing a crosslinked rubber molded article having excellent strength characteristics and compression set resistance and excellent workability can be obtained.

Further, the copolymer [A] according to the present invention has a complex viscosity (25 ° C., strain 1%) measured by using a viscoelastic device MCR-301 manufactured by Anton Paar (Australia) of 10 ⁵ Pa · sec. In the following, it is desirable that the low viscosity is preferably 4000 Pa · sec or less, more preferably 2000 Pa · sec or less.

-Production method of copolymer [A] A copolymer [A] according to the present invention is a polymerization of ethylene, an α-olefin, and a non-conjugated polyene containing a norbornene compound represented by the formula [I] described above. Specifically, for example, “Polymer production process” (published by Industrial Research Council, page 365 to 378), JP-A-9-71617 JP-A-9-71618, JP-A-9-208615, JP-A-10-67823, JP-A-10-67824, JP-A-10-110054, etc. It can be preferably prepared by the method.

  As a polymerization catalyst, a Ziegler catalyst comprising a transition metal compound such as vanadium (V), zirconium (Zr), or titanium (Ti) and an organoaluminum compound (organoaluminum oxy compound), or an element periodic table IVB A metallocene catalyst composed of a metallocene compound of a transition metal selected from the group and an organoaluminum oxy compound or an ionized ionic compound is preferably used.

Specifically, the copolymer [A] according to the present invention has a polymerization temperature of 30 to 60 ° C., particularly in the presence of a catalyst containing the following vanadium compound (a) and organoaluminum compound (b) as main components. Conditions of 30 to 50 ° C., polymerization pressure of 4 to 12 kgf / cm ² , particularly 5 to 8 kgf / cm ² , and molar ratio of non-conjugated polyene to ethylene (non-conjugated polyene / ethylene) of 0.01 to 0.2 Thus, it can be suitably produced by copolymerizing ethylene, an α-olefin, and the above-described non-conjugated polyene, particularly preferably a norbornene compound containing a vinyl group. The copolymerization is preferably carried out in a hydrocarbon medium.

Examples of the vanadium compound (a) include, for example, the general formula VO (OR) _a X _b or V (OR) _c X _d (wherein R is a hydrocarbon group, 0 ≦ a ≦ 3, 0 ≦ b ≦ 3). 2 <= a + b <= 3, 0 <= c <= 4, 0 <= d <= 4, 3 <= c + d <= 4), These electron donor adducts can be mentioned.

More specifically, VOCl ₃ , VO (OC ₂ H ₅ ) Cl ₂ , VO (OC ₂ H ₅ ) ₂ Cl, VO (O-iso-C ₃ H ₇ ) Cl ₂ , VO (On-C ₄ H ₉ ) Cl ₂ , VO (OC ₂ H ₅ ) ₃ , V
OBr ₃ , VCl ₄ , VOCl ₃ , VO (On-C ₄ H ₉ ) ₃ , VCl ₃ .2OC ₆ H ₁₂ OH
Etc. can be illustrated.

Specific examples of the organoaluminum compound (b) include trialkylaluminum such as triethylaluminum, tributylaluminum and triisopropylaluminum; dialkylaluminum alkoxide such as diethylaluminum ethoxide and dibutylaluminum butoxide; ethylaluminum sesquiethoxide and butyl Alkyl aluminum sesquialkoxides such as aluminum sesquibutoxide;
Partially alkoxylated alkylaluminum having an average composition represented by R _0.5 Al (OR) _0.5, etc .; dialkylaluminum halides such as diethylaluminum chloride, dibutylaluminum chloride, diethylaluminum bromide; ethylaluminum sesquichloride, butylaluminum sesquioxide Alkyl aluminum sesquihalides such as chloride, ethylaluminum sesquibromide, partially halogenated alkylaluminums such as alkylaluminum dihalide such as ethylaluminum dichloride, propylaluminum dichloride, butylaluminum dibromide; diethylaluminum hydride, dibutylaluminum hydride Dialkyl aluminum hydride, ethyl aluminum dihydride, etc. Partially hydrogenated alkylaluminums such as alkylaluminum dihydrides such as rualuminum dihydride; Partially alkoxylated and halogenated alkylaluminums such as ethylaluminum ethoxychloride, butylaluminum butoxycycloride, ethylaluminum ethoxybromide And so on.

Other Resin Component The rubber composition according to the present invention preferably contains only the above-described ethylene / α-olefin / non-conjugated polyene copolymer [A] as the resin component, but does not impair the object of the present invention. In addition, a resin component other than the ethylene / α-olefin / non-conjugated polyene copolymer [A] may be contained.

  As a resin component other than the copolymer [A], for example, organopolysiloxane is suitably used as an optional component. Organopolysiloxane has the effect of improving the heat aging resistance of the rubber composition, and contributes to the improvement of the heat aging resistance of fuel cell seal products, hard disk drive top cover gaskets, and wire connector seal materials.

  When the rubber composition of the present invention contains an organopolysiloxane, the content thereof is 99.9: 0.1-5 by weight ratio of ethylene / α-olefin / non-conjugated polyene copolymer: organopolysiloxane. : 95, preferably 99.9: 0.1 to 60:40, more preferably 99.9: 0.1 to 70:30.

Examples of the organopolysiloxane include those having an average composition formula represented by the following formula (S).
R ¹ _t SiO _{(4-t) / 2} (S)
(In the formula (S), R ¹ represents a monovalent hydrocarbon group having 1 to 10 carbon atoms, and part or all of the hydrogen atoms of the group may be substituted with a cyano group or a halogen group, and t is It is a number from 1.9 to 2.1.)
Specifically, R ¹ in the above formula (S) is a methyl group, an ethyl group, a propyl group, a butyl group,
Hexyl group, alkyl group such as octyl group, cycloalkyl group such as cyclopentyl group, cyclohexyl group, alkenyl group such as vinyl group, allyl group, propenyl group, cycloalkenyl group such as cyclopentenyl group, cyclohexenyl group, phenyl group, Aryl groups such as a tolyl group and xylyl group, and aralkyl groups such as a benzyl group and a phenylethyl group, and some or all of the hydrogen atoms of the group may be substituted with a chlorine atom, a fluorine atom or a cyano group .

  The organopolysiloxane includes an organopolysiloxane having a dimethylsiloxane unit in the main chain, or a diphenylsiloxane having a phenyl group, a vinyl group, a 3,3,3-trifluoropropyl group, etc. in a part of the main chain of the dimethylpolysiloxane. Particularly preferred are organopolysiloxanes having introduced units, methylvinylsiloxane units, methyl-3,3,3-trifluoropropylsiloxane units, and the like.

The organopolysiloxane preferably has two or more aliphatic unsaturated groups such as alkenyl groups and cycloalkenyl groups in one molecule, and is 0.01 to 20 mol% in R ¹ , especially 0.0.
It is preferable that 2 to 10 mol% is an aliphatic unsaturated group, particularly a vinyl group. The aliphatic unsaturated group may be at the molecular chain end, in the middle of the molecular chain, or both, but is preferably at least at the molecular chain end. Examples of the molecular chain terminal include those blocked with a trimethylsilyl group, a dimethylphenylsilyl group, a dimethylhydroxysilyl group, a dimethylvinylsilyl group, a trivinylsilyl group, and the like.

  Particularly preferable examples of the organopolysiloxane that can be used in the present invention include methyl vinyl polysiloxane, methyl phenyl vinyl polysiloxane, and methyl trifluoropropyl vinyl polysiloxane.

  Such an organopolysiloxane can be obtained by, for example, hydrolyzing and condensing one or more types of organohalogenosilanes, or by making cyclic polysiloxanes (such as siloxane trimers or tetramers) alkaline or It can be obtained by ring-opening polymerization using an acidic catalyst. These are basically linear diorganopolysiloxanes, but they may be a mixture of two or three or more different molecular structures.

The organopolysiloxane can be obtained as a commercial product, or can be obtained by synthesis by a known method disclosed.
The degree of polymerization of the organopolysiloxane is preferably 100 or more, particularly preferably 3,000 to 20,000. Further, the viscosity is preferably 100 centistokes (cSt) or more at 25 ° C., and particularly preferably 100,000 to 100,000,000 cSt.

  Further, in the rubber composition of the present invention, other rubbers known as other resin components can be used in combination as long as the object of the present invention is not impaired. Specific examples include natural rubber (NR), Examples include isoprene rubbers such as isoprene rubber (IR), butadiene rubbers (BR), styrene-butadiene rubbers (SBR), acrylonitrile-butadiene rubbers (NBR), and conjugated diene rubbers such as chloroprene rubber (CR). Furthermore, conventionally known ethylene / α-olefin copolymer rubbers such as ethylene / propylene random copolymer (EPR), and ethylene / α-olefin / non-conjugated polyenes other than the copolymer [A] of the present invention. Copolymerization can also be used.

[B] Carbon Black Carbon black [B] used in the present invention has an iodine adsorption of 80 mg / g or less, preferably 15 to 40 mg / g, and an average particle size of 250 nm or less, preferably 40 to 100 nm. There, and, DBP absorption amount 10~300cm ³ / 100g, preferably 40
~150cm is a ³ / 100g. Such carbon blacks include FEF grade, G
Commercially available carbon black such as PF grade and SRF grade can be used. Carbon black [B] acts as a reinforcing material in the rubber composition.

  Here, the iodine adsorption amount and the DBP adsorption amount are typical indexes indicating the characteristics of carbon black, and are measured based on JISK6217. The iodine adsorption amount is an indicator of the total surface area including the pores of carbon black. Further, the DBP absorption amount has a correlation with the structure, and the iodine adsorption amount and the DBP adsorption amount are reinforcing properties and extrusion properties, dispersibility, coloring power, viscosity, It has a great influence on conductivity.

  The particle diameter is an average diameter obtained by measuring and calculating a small spherical component constituting the carbon black agglomeration pair with an electron microscope image, and is closely related to the reinforcing property and blackness when blended in a rubber composition. Yes.

  For this reason, when carbon black in which any of the iodine adsorption amount, the average particle diameter, and the DBP absorption amount deviates from the above conditions is used, sufficient reinforcement cannot be obtained, or reinforcement can be obtained. However, the dough viscosity of the rubber composition becomes too high, and the moldability by LIM molding may deteriorate.

The compounding amount of the carbon black [B] is 1 to 40 parts by weight, preferably 5 to 30 parts by weight with respect to 100 parts by weight of the resin component constituting the rubber composition.
[C] Surface-modified silica The surface-modified silica [C] used in the present invention is obtained by surface-modifying precipitated silica (hydrous silicic acid), and has a BET specific surface area indicating a primary particle diameter. 30 to 80 m ² / g, preferably 40 to 60 m ² / g, and the particle size by the Coulter counter method as an index of the secondary particle size is 1.0 to 4.0 μm, preferably 1.5 to 3.0 μm And the M value is 50 or more.

As a raw material of the surface-modified silica [C] used in the present invention, precipitated silica (hydrous silicic acid) is used. Generally, as silica, gel method silica, dry silica (non-hydrous silicic acid), colloidal silica and the like are known in addition to precipitation method silica, but gel method silica has strong cohesive force and hard secondary (aggregation) particles. Since it is difficult to separate, the dispersibility is poor, and since the BET specific surface area is usually as large as 250 to 900 m ² / g, there is a problem that the rubber composition is easily thickened and the processability is poor. Colloidal silica generally has a large primary particle size and a small BET specific surface area, so that the workability is good. However, since the particles themselves are monodispersed, there is a problem that the effect of imparting reinforcing properties to the rubber composition cannot be expected. Also, dry silica is easy to loosen the secondary (aggregated) particles, but is inferior in dispersibility in rubber, and the BET specific surface area is usually relatively high at about 100 to 400 m ² / g, so that the processability is not sufficient. is there. For this reason, precipitation method silica is most suitable as a raw material for the surface-modified silica [C] of the present invention.

  Examples of the surface modification treatment of the precipitated silica include surface treatment with hexamethyldisilazane, chlorosilane, alkoxysilane, dimethyldichlorosilane, octylsilane, dimethylsilicone oil, and the like. By these surface treatments, the thickening suppression effect of the rubber composition when the surface-modified silica [C] is added can be expected.

In addition to the surface treatment, the surface-modified silica [C] used in the present invention has been subjected to mechanical treatment such as shear fracture in order to suppress steric hindrance on the silica surface due to the surface treatment. May be.

Such a surface modification treatment degree of silica is represented by an M value, and the surface-modified silica [C] used in the present invention desirably has an M value of 50 or more. The M value is a general index indicating the degree of surface modification treatment of silica. Methanol at the time of starting affinity (beginning to wet) when added to the silica to be measured while changing the methanol concentration of the methanol aqueous solution. It is a value represented by the aqueous solution concentration (vol% of methanol).

The compounding amount of the surface-modified silica [C] is preferably 20 to 60 parts by weight with respect to 100 parts by weight of the resin component constituting the rubber composition.
In the present invention, the surface-modified silica [C] acts as a reinforcing material for the rubber composition together with the carbon black [B]. However, when the blending amount is too small, the desired reinforcing property cannot be obtained, On the other hand, if the amount is too large, the viscosity becomes too high and the moldability of the rubber composition may be impaired.

  In the present invention, both the reinforcing property and the moldability of the rubber composition can be achieved by using carbon black [B] and surface-modified silica [C] as the reinforcing material. If only carbon black [B] is used as a reinforcing material for the rubber composition, the dispersibility of the carbon black is insufficient during kneading, or the cross-linked product is tacky (adhesive), resulting in poor handling of the rubber fabric. There is a case. On the other hand, in a rubber composition containing only surface-modified silica [C] until reinforcement is obtained, the viscosity may be lowered, processability may be significantly deteriorated, and LIM molding may be difficult.

[D] Crosslinking agent The rubber composition of the present invention preferably contains a crosslinking agent [D] in addition to the above-mentioned copolymer [A], carbon black [B] and surface-modified silica [C]. . As the cross-linking agent [D], a known cross-linking agent may be used as appropriate, but it is desirable to use a cross-linking agent having compatibility or good dispersibility with respect to the copolymer [A]. When the non-conjugated polyene component of [A] is a norbornene-based compound represented by the above-described formula [I], it is more preferable to use a compound having a crosslinking point SiH group.

Examples of the compound having SiH group suitably used as the crosslinking agent [D] include the SiH group-containing compound (1) having two SiH groups in one molecule represented by the following general formula [II], and the following general formula SiH group-containing compound (3) having three SiH groups in one molecule represented by the formula [III]
Is mentioned.

(In the formula [II], R ³ is a monovalent group having 1 to 10 carbon atoms, an unsubstituted or substituted saturated hydrocarbon group or an aromatic hydrocarbon group, and may be the same or different in one molecule, a is an integer of 0 to 20, b is an integer of 0 to 20, and R ⁴ is a divalent organic group having 1 to 30 carbon atoms or an oxygen atom.)

(In the formula [III], R ⁵ is a monovalent group having 1 to 10 carbon atoms, and is an unsubstituted or substituted saturated hydrocarbon group or aromatic hydrocarbon group, which may be the same or different in one molecule, a, b and c are each independently an integer of 0 to 20, and R ⁶ is a trivalent organic group having 1 to 30 carbon atoms.)
The SiH group-containing compound (1) having two SiH groups in one molecule represented by the above general formula [II] has SiH groups at both ends of the molecule, and has two SiH groups per molecule. In general formula [II], specific examples of R ³ are methyl group, ethyl group, propyl group, isopropyl group, butyl group,
Amyl group, cyclopentyl group, hexyl group, cyclohexyl group, octyl group, chloromethyl group, 2-chloroethyl group, 3-chloropropyl group, phenyl group, phenylmethyl group, 2-phenylethyl group, 2-phenylpropyl group, etc. Can be mentioned. Preferred are a methyl group, an ethyl group, and a phenyl group. a is an integer of 0 to 20, and b is an integer of 0 to 20. Preferably, both a and b are 10 or less, more preferably 5 or less, particularly preferably 2 or less, and most preferably a and b are equally 2 or less.

Specific examples of the SiH group-containing compound (1) having two SiH groups in one molecule represented by the general formula [II] are shown below. R ⁴ in the general formula [II] is a divalent organic group having 1 to 30 carbon atoms or an oxygen atom, and specific examples of the divalent organic group include divalent organic groups in the following specific compound examples. Corresponds to the group. These SiH group-containing compounds (1) can be used alone or in combination of two or more. The SiH group-containing compound (1) can be synthesized by a known method disclosed.

  Among these, the SiH group-containing compound (1) having two SiH groups in one molecule, which is particularly preferably used in the present invention, is a compound represented by the following formula.

SiH group-containing compound having three SiH groups in one molecule represented by the above general formula [III] (
2) has SiH groups at three ends of the molecule, and three SiH groups in one molecule. R ⁵ in the general formula [III] is exemplified by the same as R ^{3 in the} general formula [II], specifically, methyl group, ethyl group, propyl group, isopropyl group, butyl group, amyl group, Examples include cyclopentyl group, hexyl group, cyclohexyl group, octyl group, chloromethyl group, 2-chloroethyl group, 3-chloropropyl group, phenyl group, phenylmethyl group, 2-phenylethyl group, 2-phenylpropyl group and the like. Preferred are a methyl group, an ethyl group, and a phenyl group. a, b and c are each independently an integer of 0 to 20, preferably a, b and c are both 10 or less, more preferably 5 or less, particularly preferably 2 or less, most preferably a, b and c are equally less than or equal to 2. R ⁶ in the general formula [III] is a trivalent organic group having 1 to 30 carbon atoms, preferably a trivalent organic group having 1 to 30 carbon atoms containing silicon.

  As a particularly preferred SiH group-containing compound (2) having three SiH groups in one molecule, a compound represented by the following formula can be exemplified.

  The crosslinking agent [D] according to the present invention preferably contains these SiH group-containing compound (1) or SiH group-containing compound (2), more preferably contains at least SiH group-containing compound (1), and SiH It is particularly preferable that the group-containing compound (1) and the SiH group-containing compound (2) are included.

  When the crosslinking agent [D] contains the SiH group-containing compound (1) alone, the rubber composition can suppress the crosslinking density to some extent, and the molded product has excellent elongation characteristics, but at low temperatures (−30 ° C. There is room for improvement in the elastic recovery rate (TR recovery rate).

When the cross-linking agent [D] contains the SiH group-containing compound (2) alone, the rubber composition is three-dimensionally cross-linked to improve rubber physical properties such as mechanical strength, but is inferior in recoverability and easily causes scorch. such as poor handling property at the time of molding, the rubber composition of the fuel cell sealing member, LIM molding gasket material, for use as such electric wire connector sealing member there is room for improvement in that may exhibit properties not suitable.

When the crosslinking agent [D] contains both the SiH group-containing compound (1) and the SiH group-containing compound (2), the rubber composition has good moldability, excellent heat resistance, barrier properties, and sealing properties. at high temperatures (0.99 ° C.) compression set is low in excellent elastic recovery at low temperatures (-30 ° C.) (TR recovery ratio), the fuel cell sealing member, LIM molding gasket material, electric wire connector sealing member, etc. It can use suitably for the use of.

  When the crosslinking agent [D] contains the SiH group-containing compound (1), the rubber composition of the present invention is composed of an ethylene / α-olefin / nonconjugated polyene copolymer [A] and other resins constituting the rubber composition. The SiH group-containing compound (1) having two SiH groups in one molecule is preferably 3.0 to 7.0 parts by weight, more preferably 4.0 to 6 parts per 100 parts by weight of the total amount with the components. It is desirable to contain 5 parts by weight.

  When the cross-linking agent [D] contains the SiH group-containing compound (2) having three SiH groups in one molecule, the rubber composition of the present invention is an ethylene / α-olefin / non-conjugated polyene copolymer [A ] And the other resin component constituting the rubber composition, the SiH group-containing compound (2) having 3 SiH groups in one molecule is preferably 0.1 to 2.0 with respect to 100 parts by weight of the total amount. It is desirable to contain 0.2 parts by weight, more preferably 0.2 to 1.0 parts by weight.

In the present invention, the crosslinking agent [D] contains a SiH group-containing compound (1) having two SiH groups in one molecule and a SiH group-containing compound (2) having three SiH groups in one molecule, and rubber The composition preferably contains the SiH group-containing compound (1) with respect to 100 parts by weight of the total amount of the ethylene / α-olefin / non-conjugated polyene copolymer [A] and other resin components constituting the rubber composition. Contains 3.0 to 7.0 parts by weight, more preferably 4.0 to 6.5 parts by weight, and the SiH group-containing compound (2) is preferably 0.1 to 2.0 parts by weight, more preferably It is particularly preferable to contain 0.2 to 1.0 part by weight.

Rubber composition The rubber composition of the present invention contains a resin component containing an ethylene / α-olefin / non-conjugated polyene copolymer [A] as essential components, carbon black [B] and surface-modified silica [C]. If necessary, the crosslinking agent [D], and further, if necessary, a catalyst, reaction inhibitor, a conventionally known inorganic filler, softening agent, anti-aging agent, processing aid, vulcanization accelerator, organic peroxide, It contains other components such as oxides, crosslinking aids, foaming agents, colorants, dispersants, flame retardants.

-Preparation of rubber composition The rubber composition of the present invention is, for example, a Banbury mixer, a kneader, a planetary mixer, an internal mixer such as an intermix, a two-roll, a three-roll, etc. A rubber reinforcing agent containing carbon black [B] and surface-modified silica [C], and an inorganic filler that is added as necessary, with a copolymer [A] and other resin components as required by a kneading apparatus , Kneaded together with other components such as softener, preferably at a temperature of 50 to 180 ° C. for 3 to 10 minutes, and then using a roll such as an open roll or a kneader to crosslink a SiH group-containing compound or the like [D] is further mixed with a catalyst and a reaction inhibitor, which will be described later, if necessary, a vulcanization accelerator and a crosslinking assistant, and the roll temperature is 100 ° C. or lower for 1 to 30 minutes. After kneading for a short time, it can be prepared by dispensing.

In addition, when the kneading temperature in the internal mixer is low, all the components constituting the rubber composition may be mixed and kneaded at the same time.
Crosslinking Method / Catalyst In the production of the rubber composition of the present invention, when crosslinking is performed using a crosslinking agent [D] such as a SiH group-containing compound, the catalyst used in the crosslinking is an addition reaction catalyst, and the copolymer [A] It promotes an addition reaction (such as a hydrosilylation reaction of an alkene) between the alkenyl group of the resin component containing silane and the SiH group of the SiH group-containing compound.

  As such a catalyst, an addition reaction catalyst composed of a platinum group element such as a platinum-based catalyst, a palladium-based catalyst, or a rhodium-based catalyst is usually used. In the present invention, a platinum-based catalyst is preferable. It is desirable to use a complex of a group 8 element metal of the periodic table including a platinum-based catalyst, particularly preferably platinum and a compound containing a vinyl group and / or a carbonyl group.

  As the compound containing a carbonyl group, carbonyl, octanal and the like are preferable. Specific examples of the complex of these with platinum include a platinum-carbonyl complex, a platinum-octanal complex, a platinum-carbonylbutyl cyclic siloxane complex, and a platinum-carbonylphenyl cyclic siloxane complex.

  As the compound containing a vinyl group, a vinyl group-containing organosiloxane is preferable. Specific examples of complexes of these with platinum include platinum-divinyltetramethyldisiloxane complex, platinum-divinyltetraethyldisiloxane complex, platinum-divinyltetrapropyldisiloxane complex, platinum-divinyltetrabutyldisiloxane complex, platinum -Divinyltetraphenyldisiloxane complex.

  Among the vinyl group-containing organosiloxanes, vinyl group-containing cyclic organosiloxanes are preferable. Examples of the complex of platinum with platinum include a platinum-vinylmethyl cyclic siloxane complex, a platinum-vinylethyl cyclic siloxane complex, and a platinum-vinylpropyl cyclic siloxane complex.

  The vinyl group-containing organosiloxane itself may be a ligand for a metal, but may be used as a solvent for coordinating other ligands. A complex in which a vinyl group-containing organosiloxane is used as a solvent and the above-mentioned compound containing a carbonyl group is a ligand is particularly preferable as a catalyst.

  Specific examples of such complexes include a platinum-carbonyl complex vinylmethyl cyclic siloxane solution, a platinum-carbonyl complex vinylethyl cyclic siloxane solution, a platinum-carbonyl complex vinylpropyl cyclic siloxane solution, and a platinum-carbonyl complex divinyl. Tetramethyldisiloxane solution, platinum-carbonyl complex divinyltetraethyldisiloxane solution, platinum-carbonyl complex divinyltetrapropyldisiloxane solution, platinum-carbonyl complex divinyltetrabutyldisiloxane solution, platinum-carbonyl complex divinyltetraphenyldi A siloxane solution is mentioned.

  The catalyst comprising these complexes may further contain components other than the compound containing a vinyl group and / or a carbonyl group. For example, a solvent other than a compound containing a vinyl group and / or a carbonyl group may be contained. Examples of these solvents include various alcohols and xylene, but are not limited thereto.

  Specific examples of the alcohol include aliphatic saturated alcohols represented by methanol and ethanol; aliphatic unsaturated alcohols such as allyl alcohol and crotyl alcohol; alicyclic alcohols such as cyclopentanol and cyclohexanol; benzyl Aromatic alcohols such as alcohol and cinnamyl alcohol; heterocyclic alcohols such as furfuryl alcohol and the like.

  An example of using alcohol as a solvent is a platinum-octanal / octanol complex. By including these solvents, there are advantages such as easy handling of the catalyst and easy mixing with the rubber composition.

  Among the various catalysts mentioned above, a platinum-carbonyl complex vinylmethyl cyclic siloxane solution (a complex represented by the following chemical formula 1 is preferred), a platinum-vinylmethyl cyclic siloxane complex (a complex represented by the chemical formula 2 is particularly preferred). ), A platinum-divinyltetramethyldisiloxane complex (in particular, a complex represented by Chemical Formula 3), a platinum-octanal / octanol complex and the like are practically preferred, and among them, a platinum-carbonylvinylmethyl cyclic siloxane complex is particularly preferred.

Chemical formula 1: Pt ⁰ .CO. (CH ₂ ═CH (Me) SiO) ₄
Chemical formula 2: Pt ⁰ · (CH ₂ ═CH (Me) SiO) ₄
Chemical formula 3: Pt ⁰ -1.5 [(CH ₂ ═CH (Me) ₂ Si) ₂ O]
The ratio of Group 8 element metal (preferably platinum) contained in these catalysts is usually 0.1 to 10% by weight, preferably 1 to 5% by weight, more preferably 2 to 4% by weight, particularly preferably. Is 2.5 to 3.5% by weight.

Although a catalyst is not specifically limited, 0.1-100,000 weight is with respect to the sum total of the resin component whole, ie, the copolymer [A], and the other resin component added as needed. ppm, preferably 0.1 to 10,000 ppm by weight, more preferably 0.1 to 5,000 ppm by weight, and particularly preferably 5 to 1,000 ppm by weight. When the catalyst is used in a proportion within the above range, a rubber composition capable of forming a crosslinked rubber molded article having an appropriate crosslinking density and excellent strength properties and elongation properties can be obtained. If the catalyst is used in a proportion exceeding 100,000 ppm by weight, it is not preferable because it is disadvantageous in cost. It is also possible to obtain a crosslinked rubber molded article by irradiating an uncrosslinked rubber molded article of a rubber composition not containing a catalyst with light, γ-ray, electron beam or the like.

  In the crosslinking of the rubber composition of the present invention, both addition crosslinking and radical crosslinking may be performed using an organic peroxide in addition to the above catalyst. The organic peroxide is used at a ratio of about 0.1 to 10 parts by weight with respect to 100 parts by weight of the resin component. As the organic peroxide, a conventionally known organic peroxide that is usually used in crosslinking of rubber can be used.

-Reaction inhibitor In crosslinking, it is preferable to use a reaction inhibitor together with the above catalyst. Reaction inhibitors include benzotriazole (for example, ethynyl group-containing alcohols such as ethynylcyclohexanol, acrylonitrile, N, N-diallylacetamide, N, N-diallylbenzamide, N, N, N ′, N′-tetraallyl-o Amide compounds such as phthalic acid diamide, N, N, N ′, N′-tetraallyl-m-phthalic acid diamide, N, N, N ′, N′-tetraallyl-p-phthalic acid diamide, sulfur, phosphorus, nitrogen And organic peroxides such as amine compounds, sulfur compounds, phosphorus compounds, tin, tin compounds, tetramethyltetravinylcyclotetrasiloxane, and hydroperoxide.

  The reaction inhibitor is 0 to 50 parts by weight, usually 0.0001 to 50 parts by weight, preferably 0.0001 based on 100 parts by weight of the total of the copolymer [A] and other resin components as necessary. -30 parts by weight, more preferably 0.0001-20 parts by weight, still more preferably 0.0001-10 parts by weight, particularly preferably 0.0001-5 parts by weight. Use of a reaction inhibitor in a proportion exceeding 50 parts by weight is not preferable because it is disadvantageous in cost.

  In the rubber composition of the present invention, a conventionally known rubber reinforcing agent other than carbon black [B] or surface-modified silica [C], an inorganic filler, a softener, Additives such as anti-aging agents, processing aids, vulcanization accelerators, organic peroxides, crosslinking aids, foaming agents, foaming aids, colorants, dispersants, flame retardants, etc., do not impair the purpose of the present invention It can mix | blend in the range. Representative examples are taken as fillers and compounding agents and will be described in more detail below.

(I) Rubber Reinforcing Agent A rubber reinforcing agent has an effect of enhancing mechanical properties such as tensile strength, tear strength, and abrasion resistance of a crosslinked (vulcanized) rubber. Since the rubber composition of the present invention contains carbon black [B] and surface-modified silica [C], a sufficient reinforcing effect can be obtained without containing other rubber reinforcing materials, but other rubbers that can be added. Specific examples of the reinforcing agent include carbon blacks other than the carbon black [B], silicas other than the surface-modified silica [C], and fine powder silicic acid.

  The type and blending amount of these rubber reinforcing agents can be appropriately selected depending on the application, but the blending amount of the rubber reinforcing agent (including the amount of [B] component and [C] component) is usually ethylene, α-olefin, The maximum amount is 300 parts by weight, preferably 200 parts by weight, based on 100 parts by weight in total of the non-conjugated polyene copolymer [A] and other resin components added as necessary.

(Ii) Inorganic filler Specific examples of the inorganic filler include light calcium carbonate, heavy calcium carbonate, talc, clay, diatomaceous earth, and the like. These inorganic fillers can be used alone or in combination of two or more. The type and blending amount of these inorganic fillers can be appropriately selected depending on the use, but the blending amount of the inorganic filler is usually the sum of the copolymer [A] and other resin components added as necessary. The amount is 1 to 300 parts by weight, preferably 200 parts by weight, per 100 parts by weight.

(Iii) Softening agent As the softening agent, a known softening agent usually used for rubber can be used. Specifically, process oil, lubricating oil, paraffin, liquid paraffin, petroleum asphalt, petroleum softener such as petroleum jelly, coal tar softener such as coal tar and coal tar pitch, castor oil, linseed oil, rapeseed oil, Fatty oil-based softeners such as coconut oil, waxes such as beeswax, carnauba wax, lanolin, fatty acids and fatty acid salts such as ricinoleic acid, palmitic acid, barium stearate, calcium stearate, zinc laurate, petroleum resin, atactic polypropylene Synthetic polymers such as coumarone indene resin, and others include tall oil and sub. Of these, petroleum softeners are preferably used, and process oil is particularly preferably used. The blending amount of these softeners is appropriately selected depending on the use of the crosslinked product. These softening agents can be used alone or in combination of two or more.

(Iv) Anti-aging agent In the present invention, an anti-aging agent may be used for the purpose of improving heat resistance. As the anti-aging agent, conventionally known anti-aging agents can be used without particular limitation, and examples thereof include amine-based, hindered phenol-based, and sulfur-based anti-aging agents. The amount of the anti-aging agent is used within a range that does not impair the object of the present invention. In addition, the anti-aging agents exemplified below can be used in the amine system, hindered phenol system, and sulfur system, either in the same system or between different systems, alone or in combination of two or more.

  Examples of amine-based antioxidants include diphenylamines and phenylenediamines. In particular, 4,4 ′-(α, α-dimethylbenzyl) diphenylamine and N, N′-di-2-naphthyl-p-phenylenediamine are preferable.

Hindered phenolic antioxidants include tetrakis [methylene-3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) propionate methane, and 3,9-bis [2- {3- (3-tert-Butyl-4-hydroxy-5-methylphenyl) propionyloxy} -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane phenol Compounds are preferred.

  Sulfur-based antioxidants include, in particular, 2-mercaptobenzimidazole, zinc salt of 2-mercaptobenzimidazole, 2-mercaptomethylbenzimidazole, zinc salt of 2-mercaptomethylbenzimidazole, pentaerythritol-tetrakis- (β-lauryl) -Thiopropionate) is preferred.

(V) Processing aids As the processing aids, known compounds used in normal rubber processing can be used. Specifically, higher fatty acids such as ricinoleic acid, stearic acid, palmitic acid and lauric acid; salts of higher fatty acids such as barium stearate, zinc stearate and calcium stearate; ricinoleic acid, stearic acid, palmitic acid and lauric acid And higher fatty acid esters. The amount of the processing aid is 10 parts by weight or less, preferably 5 parts by weight or less based on 100 parts by weight of the total of the copolymer [A] and other resin components added as necessary. However, it is desirable to appropriately determine the optimum amount according to the required physical property value.

(Vi) Crosslinking aid In the crosslinking of the rubber composition of the present invention, when an organic peroxide is used, it is preferable to use a crosslinking aid in combination. Specific examples of the crosslinking aid include sulfur, quinone dioxime compounds such as p-quinone dioxime, methacrylate compounds such as polyethylene glycol dimethacrylate, allyl compounds such as diallyl phthalate and triallyl cyanurate, maleimide compounds, Examples include divinylbenzene. Such a crosslinking aid is used in an amount of 0.5 to 2 mol, preferably about equimolar to 1 mol of the organic peroxide used.
<Fuel cell seal material, hard disk drive top cover gasket, wire connector seal material>
Molding / Crosslinking Method The rubber composition of the present invention described above is excellent in mechanical properties and heat resistance, so it is particularly suitable for applications such as fuel cell seal materials, hard disk drive top cover gaskets, and wire connector seal materials. Can be used. The rubber composition of the present invention is particularly suitable for LIM molding, but a molded product can be produced by other molding methods.

  The fuel cell seal material, hard disk drive top cover gasket, and wire connector seal material (hereinafter abbreviated as each material of the present invention) of the present invention can exhibit their characteristics most when used as a crosslinked rubber molded product. it can.

  In order to produce a crosslinked rubber molded article from the rubber composition of the present invention, an uncrosslinked rubber composition is prepared once by the preparation method shown above, as in the case of vulcanizing (crosslinking) ordinary rubber. Then, it is preferable to form a rubber composition into an intended shape and then crosslink.

  The composition of the present invention prepared as described above uses a LIM molding machine, an injection molding machine, a transfer molding machine, a press molding machine, an extrusion molding machine, a calender roll, an ink jet molding machine, a screen printing machine, and the like. It is molded into the intended shape by various molding methods. Among these, the LIM molding machine is suitable for manufacturing each material of the present invention which is intended from the viewpoint of thickness accuracy and high speed molding. Injection molding and compression molding are also suitable.

Crosslinking can be performed simultaneously with molding or by introducing the molded product into a vulcanizing tank.
For example, the rubber composition of the present invention mixed using various kneading apparatuses such as three mill rolls, open rolls, two open rolls, a Banbury mixer, an internal mixer, a kneader, a planetary mixer, and a high shear mixer, It is molded under a crosslinking condition of 80 to 230 ° C., preferably 100 to 180 ° C., and is subjected to crosslinking molding at about 100 to 230 ° C., preferably about 120 to 150 ° C. for about 0.5 to 24 hours as necessary. The molding and crosslinking can be performed by heat treatment (secondary vulcanization) in an air oven such as a gear oven or a thermostatic bath. Crosslinking or secondary crosslinking (secondary vulcanization) may be performed by irradiation with light, γ rays, electron beams, or the like, and crosslinking may be performed at room temperature. By the above-described method, a crosslinked rubber molded body, that is, each material of the present invention is obtained.

  In this crosslinking step, a mold may be used, or the crosslinking may be performed without using a mold. When a mold is not used, the molding and crosslinking processes are usually carried out continuously. As a heating method in the vulcanization tank, a heating tank such as hot air, glass bead fluidized bed, UHF (ultra-high frequency electromagnetic wave), steam or the like can be used.

LIM Molding When the rubber composition of the present invention is applied particularly to LIM molding, a resin component containing a copolymer [A] and a composition containing a crosslinking agent, a resin component containing a copolymer [A], and a catalyst It is preferable to prepare a rubber composition of the present invention by mixing the two with a LIM molding apparatus and mold the rubber composition of the present invention. Here, components other than the resin component, the crosslinking agent and the catalyst may be contained in either composition, or may be contained in both.

Although it depends on the viscosity of the material, specifically, for example, by using an internal mixer (closed mixer) such as a Banbury mixer, a kneader, or an intermix, or a stirrer such as a planetary mixer, the copolymer [ A], other resin components, rubber reinforcing agents containing [B] and [C] components, crosslinking agents, inorganic fillers, softeners and other additives are kneaded for 3 to 10 minutes to obtain a liquid rubber composition (1). To prepare. On the other hand, copolymer [A], other resin components, rubber reinforcing agent, inorganic filler, softener and other additives and the above catalyst, and if necessary, a reaction inhibitor are kneaded for 3 to 10 minutes to form a liquid rubber composition A product (2) is prepared. Defoam is performed as necessary. Subsequently, the liquid rubber composition (1) and the liquid rubber composition (2) are put into a dedicated pail can or a directly connectable cartridge that can be directly connected to the LIM molding apparatus, and the LIM molding is performed through a metering and mixing apparatus. By applying the above, each material of the present invention can be obtained.

Fuel cell seal material In a fuel cell, it is important to seal cells, and this seal needs to be particularly excellent in gas barrier properties and the like. An example of the shape of the seal will be described with reference to the drawings.

  The sealing material has, for example, a shape as indicated by reference numeral 3 in FIGS. The planar shape of the sealing material has a planar outer shape as indicated by reference numeral 3 in FIG. 1 and 2 indicate a carbon, metal or resin separator, 3 indicates a sealing material portion, and 2 in FIG. 1 indicates a gap.

The fuel cell sealing material of the present invention is preferably so-called void-free without voids due to foaming or the like.
The volume specific resistance of the fuel cell sealing material of the present invention is desirably 1 × 10 ¹⁰ ohm · cm or more. Volume resistivity is one of the characteristics required for sealing materials used for electric / electronic parts and is an index of electrical insulation. More preferably, it is 1 × 10 ¹² ohm · cm or more, and shows suitable performance as a sealing material. The volume resistivity is SR using a 1 mm thick sheet obtained by press-crosslinking the rubber composition at a pressure of 40 kgf / cm ² at 150 ° C. for 10 minutes.
Measured according to IS2301-1969.

The fuel cell of the present invention has such a fuel cell sealing material of the present invention.
Hard disk drive top cover gasket The hard disk drive top cover gasket of the present invention preferably has a crosslinked rubber sheet having a compression set of 50% or less obtained by the above-mentioned method in the gasket portion, and has a sufficient sealing performance in the product. It becomes. Moreover, it is preferable that the tensile strength is 2 MPa or more and the tensile elongation at break is 200% or more, so that there are fewer problems that the product is easily broken in the manufacturing process. Further, the hardness (JIS K6253) of the crosslinked rubber sheet is preferably less than 70 degrees. When the hardness is 70 degrees or more, the reaction force when the cover-integrated gasket is attached to the main body is increased, and the cover is deformed. In some cases, the gasket cannot be completely sealed, and the sealing performance as a gasket may be inferior. The hardness is preferably 10 degrees or more, and if it is less than 10 degrees, problems such as easy tearing of the gasket and easy adhesion occur. The most preferred hardness is 20 to 40 degrees.

  Examples of the adhesive used when the hard disk drive top cover and the gasket are integrated include an epoxy resin-based or phenol resin-based adhesive, an isocyanate-based or silane-based coupling agent, and the like. As the method for applying the adhesive, an optimum method such as dip coating, spray coating, screen printing, brush coating, or stamp method is selected as necessary.

The hard disk drive top cover gasket of the present invention is preferably so-called void-free, having no voids due to foaming or the like.
Electric wire connector sealing material for electric wire connector sealing member present invention, which consist of a rubber composition of the present invention described above, for example, a solid polymer electrolyte (solid polymer electrolyte) for electric wire connector sealing member It is preferable.

  In the wire connector seal of the present invention, it is preferable that the duro A hardness indicating the surface hardness of the cured product layer is 45 or less. Duro A hardness is an index of hardness and can be measured according to JIS K6253. In order to reduce the durometer A hardness to 45 or less, it is possible to adjust the addition ratio of various reinforcing agents, fillers, plasticizers and the like in the composition, and these various additives are not added. Also shows the desired low hardness. The lower limit is 5 or more, and if it exceeds the lower limit, it is too soft and the performance of sealing the electric wire connector is inferior. However, as the reinforcing agent and filler, those containing a substance that becomes a catalyst poison such as sulfur or a halogen compound are not preferable.

The wire connector of the present invention has such a wire connector seal of the present invention. The electric wire connector according to the present invention is particularly preferably an automobile electric wire connector.
EXAMPLES Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to these examples.

[Example 1]
Ethylene / propylene / 5-vinyl-2-norbornene random copolymer (PX-062 manufactured by Mitsui Chemicals, Inc., ethylene content: 52.7% by weight, VNB content: 4.7% by weight, complex viscosity at 25 ° C. ( Viscoelasticity device manufactured by Anton Paar (Australia) (complex viscosity measured using MCR301): 1100 Pa · S, intrinsic viscosity [η] measured in decalin solution at 135 ° C .: 0.28 dl / g) 100 parts by weight , carbon black (Asahi carbon Co., Ltd. Asahi # 50HG, iodine adsorption: 19 mg / g, average particle size 85 n m, DBP absorption amount: 110cm ³ / 100g) and 15 parts by weight, precipitated silica and surface treated 1 (Tosoh E75SS manufactured by Silica, BET surface area: 50 m ² / g, secondary particle diameter (average particle diameter determined by Coulter counter method): 2.4 μm, M value: 65) 30 parts by weight with a 2 liter planetary mixer [manufactured by Inoue Seisakusho Co., Ltd., trade name: PLM-2 type] in a range of 50 to 80 ° C. 0.4 part by weight of 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionic acid stearate as an anti-aging agent (Irganox 1076 manufactured by Ciba Specialty Chemicals), and platinum-1,3 as a catalyst , 5,7-tetravinylmethylcyclosiloxane complex [platinum concentration 0.5% by weight, terminal vinylsiloxane oil solution] 0.4 part by weight, 1-ethynyl-1-cyclohexanol 0.1 part by weight as a reaction inhibitor, 5 parts by weight of a compound represented by the following formula (1) (hereinafter referred to as crosslinking agent 1) and 0.3 part by weight of a compound represented by the following formula (2) (hereinafter referred to as crosslinking agent 2) were added. To a three-roll mill The rubber composition was prepared.

The obtained rubber composition was poured into a test sheet mold (140 × 100 × 2 mm), compression molded for 5 minutes at a hot plate set temperature of 150 ° C. and a mold compression of 80 MPa to obtain a crosslinked rubber sheet, and further in an air oven Secondary vulcanization was performed at 150 ° C. for 1 hour to obtain a crosslinked rubber sheet.

Each property of the obtained crosslinked rubber sheet was measured or evaluated by the following method. The results are shown in Table 1.
(1) Hardness Based on JIS K6253, A hardness was measured by the durometer method at the measurement temperature of 23 degreeC.
(2) Tensile test In accordance with JIS K6251, a tensile test was performed under the conditions of a measurement temperature of 23 ° C and a tensile speed of 500 mm / min, and the tensile strength and elongation at break of the crosslinked sheet were measured.
(3) Complex viscosity (zero shear viscosity)
The complex viscosity of the rubber composition is determined using a viscoelastic device MCR3 manufactured by Anton Paar (Australia).
01 was used and measured at 25 ° C. In order to obtain good moldability, 5000 Pa · sec or less is preferable.
(4) Compression set In accordance with JIS K6262 (1997), 3 sheets of 2 mm sheets were laminated, the compression set at 150 ° C. for 70 hours in air was measured, and the compression set rate was determined. . The measurement conditions are after high-temperature treatment at 150 ° C. × 70 to 500 hours at a high temperature.

Although as a stationary fuel cell sealing member for the home has been required performance of 90 ° C. 40,000 hours, results of the study, found that it is accelerated to sufficient evaluation in the evaluation of 1 50 ° C. 500 hours It was. That is, if it is less than 80% at 150 ° C. for 500 hours, the performance at 90 ° C. for 40,000 hours can be satisfied.
(5) TR recovery rate In accordance with JIS K6261, a low temperature elastic recovery test (TR test) at -30 ° C was performed to obtain a TR recovery rate. If the recovery rate is 55% or less, the low temperature property cannot be satisfied.
(6) Hot characteristics (90 ° C)
In accordance with JIS K6251, a tensile test was performed under the conditions of a measurement temperature of 90 ° C. and a tensile speed of 500 mm / min, and the tensile strength and elongation at break of the crosslinked sheet were measured. In addition, if the elongation at break at 90 ° C. is less than 200%, the performance cannot be satisfied.

[Example 2]
In Example 1, a crosslinked rubber sheet was produced in the same manner as in Example 1 except that the crosslinking agent 2 was not used, and the properties were evaluated. The results are shown in Table 1.

[Example 3]
In Example 1, a crosslinked rubber sheet was produced in the same manner as in Example 1 except that the amount of crosslinking agent 1 used was 6.5 parts by weight and the amount of crosslinking agent 2 used was 0.3 parts by weight. The properties were evaluated. The results are shown in Table 1.

[Example 4]
In Example 1, a crosslinked rubber sheet was produced in the same manner as in Example 1 except that the amount of the crosslinking agent 1 was 7 parts by weight and the amount of the crosslinking agent 2 was 1 part by weight. evaluated. The results are shown in Table 1.

[Example 5]
In Example 1, the amount of the crosslinking agent 1 used was 3.5 parts by weight, and the amount of the crosslinking agent 2 used was 1 part by weight. The properties were evaluated. The results are shown in Table 1.

[Example 6]
In Example 1, instead of the surface-treated precipitation method silica 1 as the surface-modified silica, surface-treated precipitation method silica 2 (E743SS manufactured by Tosoh Silica Co., Ltd., BET surface area: 45 m ²⁾
/ G, secondary particle diameter: 1.7 μm, M value: 65) A crosslinked rubber sheet was produced in the same manner as in Example 1 except that 30 parts by weight was used, and the properties were evaluated. The results are shown in Table 1.

[Example 7]
In Example 1, instead of the surface-treated precipitation method silica 1 as the surface-modified silica, surface-treated precipitation method silica 2 (E743SS manufactured by Tosoh Silica Co., Ltd., BET surface area: 45 m ²⁾
/ G, secondary particle diameter: 1.7 μm, M value: 65) A crosslinked rubber sheet was produced in the same manner as in Example 1 except that 30 parts by weight and the crosslinking agent 2 was not used. The properties were evaluated. The results are shown in Table 1.

[Example 8]
In Example 1, a crosslinked rubber sheet was produced in the same manner as in Example 1 except that the crosslinking agent 1 was not used and the amount of the crosslinking agent 2 used was 5 parts by weight, and the properties were evaluated. The results are shown in Table 1.

[Comparative Example 1]
In Example 1, instead of the surface-treated precipitation method silica 1, precipitation method silica 3 (E75 manufactured by Tosoh Silica Co., BET surface area: 54 m ² / g, secondary particle size:
2.3 μm, M value: 0) A crosslinked rubber sheet was produced in the same manner as in Example 1 except that 30 parts by weight and the crosslinking agent 2 was not used, and the properties were evaluated. The results are shown in Table 2.

[Comparative Example 2]
In Example 1, instead of the surface-treated precipitation method silica 1, precipitation method silica 4 (E200 manufactured by Tosoh Silica Co., Ltd., BET surface area: 132 m ² / g, secondary particle size: 3.3 μm) , M value: 0) A crosslinked rubber sheet was produced in the same manner as in Example 1 except that 30 parts by weight and no crosslinking agent 2 was used, and properties were evaluated. The results are shown in Table 2.

[Comparative Example 3]
In Example 1, instead of the surface-treated precipitation method silica 1 as the surface-modified silica, surface-treated precipitation method silica 5 (SS10 manufactured by Tosoh Silica Co., Ltd., BET surface area: 90 m ² / g)
Secondary particle size: 2.9 μm, M value: 65) A crosslinked rubber sheet was produced in the same manner as in Example 1 except that 30 parts by weight and no crosslinking agent 2 was used. evaluated. The results are shown in Table 2.

[Comparative Example 4]
In Example 1, instead of the surface-treated precipitation method silica 1 as the surface-modified silica, surface-treated precipitation method silica 6 (SS70 manufactured by Tosoh Silica Co., Ltd., BET surface area: 49 m ² / g)
Secondary particle size: 4.5 μm, M value: 65) A crosslinked rubber sheet was produced in the same manner as in Example 1 except that 30 parts by weight and no crosslinking agent 2 was used. evaluated. The results are shown in Table 2.

[Comparative Example 5]
In Example 1, instead of the surface-treated precipitation method silica 1 as the surface-modified silica, surface-treated precipitation method silica 6 (SS70 manufactured by Tosoh Silica Co., Ltd., BET surface area: 49 m ² / g)
Secondary particle size: 4.5 μm, M value: 65) A crosslinked rubber sheet was produced in the same manner as in Example 1 except that 30 parts by weight were used, and the properties were evaluated. The results are shown in Table 2.

[Comparative Example 6]
In Example 1, instead of the surface-treated precipitation method silica 1 as the surface-modified silica, surface-treated precipitation method silica 7 (SS30P manufactured by Tosoh Silica Co., Ltd., BET surface area: 110 m ²⁾
/ G, secondary particle diameter: 8.5 μm, M value: 55) A crosslinked rubber sheet was produced in the same manner as in Example 1 except that 30 parts by weight and the crosslinking agent 2 was not used. The properties were evaluated. The results are shown in Table 2.

[Comparative Example 7]
In Example 1, 40 parts by weight of talc (L-1 manufactured by Nippon Talc Co., Ltd., BET specific surface area: 11 m ² / g, secondary particle size: 4.9 μm) was used instead of the surface-treated precipitation method silica 1. A crosslinked rubber sheet was produced in the same manner as in Example 1 except that the crosslinking agent 2 was not used, and the properties were evaluated. The results are shown in Table 2.

[Comparative Example 8]
In Example 1, instead of the surface-treated precipitation method silica 1, 40 parts by weight of surface-treated calcined kaolin (Translink 37 manufactured by BSAF, secondary particle size: 1.4 μm) was used, and the crosslinking agent 2 was not used. Except for this, a crosslinked rubber sheet was produced in the same manner as in Example 1, and the properties were evaluated. The results are shown in Table 2.

  The properties of silica and talc used in the above Examples and Comparative Examples are shown in Table 3.

From the above results, it can be seen that in Example 8 in which a large amount of the crosslinking agent 2 was blended, the crosslinked rubber sheet could be produced, but the elongation at break at 90 ° C. was small and the possibility of compression cracking was increased. It can be seen that Comparative Example 4 and Comparative Example 5 in which silica having a large average particle size is blended have poor low-temperature characteristics. In Comparative Examples 1 to 3 and Comparative Example 6, it can be seen that the viscosity of the composition is high and the moldability may be insufficient. Moreover, it turns out that it is inferior to long-term CS in the comparative example 7 and the comparative example 8 using fillers other than the precipitation method 1 which carried out the surface treatment.

  The rubber composition of the present invention is suitable for LIM molding, and is suitably used for various gasket materials such as fuel cell seal materials, hard disk drive top cover gasket materials, and wire connector seal materials.

FIG. 1 is a perspective view illustrating an example of a fuel cell separator-integrated cell seal component. FIG. 2 is a schematic cross-sectional view taken along line AA in FIG.

Explanation of symbols

1: Fuel cell separator-integrated cell carbon, metal or resin separator 2: Air gap 3: Cell seal parts

Claims (12)

An ethylene / α-olefin / non-conjugated polyene copolymer [A] satisfying the following (a) to (e):
(A) a copolymer of ethylene, α-olefin, and non-conjugated polyene;
(B) the α-olefin has 3 to 20 carbon atoms,
(C) The weight ratio of ethylene unit / α-olefin unit is 35/65 to 95/5,
(D) the iodine value is in the range of 0.5-50,
(E) The intrinsic viscosity [η] measured in a decalin solution at 135 ° C. is 0.01 to 5.0 dl / g;
Iodine adsorption of not more than 80 mg / g, an average particle diameter of at 250nm or less, and the carbon black [B] DBP absorption is 10~300cm ³ / 100g,
The BET specific surface area obtained by surface modification of the precipitated silica is 30 to 80 m ² / g, the particle diameter by the Coulter counter method is 1.0 to 4.0 μm, and the M value is 50 or more. A surface-modified silica [C] ,
SiH group-containing compound (1) having two SiH groups in one molecule represented by the following general formula [II] and three SiH groups in one molecule represented by the following general formula [III] at least one kind of crosslinking agent selected from SiH group-containing compound (2) [D] and Ri Na contain,

(In the formula [II], R ³ is a monovalent group having 1 to 10 carbon atoms, an unsubstituted or substituted saturated hydrocarbon group or an aromatic hydrocarbon group, and may be the same or different in one molecule, a is an integer of 0 to 20, b is an integer of 0 to 20, and R ⁴ is a divalent organic group having 1 to 30 carbon atoms or an oxygen atom.)

(In the formula [III], R ⁵ is a monovalent group having 1 to 10 carbon atoms, and is an unsubstituted or substituted saturated hydrocarbon group or aromatic hydrocarbon group, which may be the same or different in one molecule, a, b and c are each independently an integer of 0 to 20, and R ⁶ is a trivalent organic group having 1 to 30 carbon atoms.)
1 to 40 parts by weight of carbon black [B] with respect to 100 parts by weight of the total amount of ethylene / α-olefin / non-conjugated polyene copolymer [A] and other resin components constituting the rubber composition, surface Containing 20-60 parts by weight of modified silica [C],
When the crosslinking agent [D] contains the SiH group-containing compound (1) having two SiH groups in one molecule, the ethylene / α-olefin / non-conjugated polyene copolymer [A] and the other constituting the rubber composition Containing 3.0 to 7.0 parts by weight of SiH group-containing compound (1) having two SiH groups in one molecule with respect to 100 parts by weight in total with the resin component of
When the cross-linking agent [D] contains the SiH group-containing compound (2) having three SiH groups in one molecule, the ethylene / α-olefin / non-conjugated polyene copolymer [A] and the other constituting the rubber composition A rubber composition comprising 0.1 to 2.0 parts by weight of a SiH group-containing compound (2) having 3 SiH groups in one molecule with respect to 100 parts by weight of the total amount of the resin component object. The rubber composition according to claim 1, wherein the ethylene / α-olefin / non-conjugated polyene copolymer [A] further satisfies the following (f):
(F) The non-conjugated polyene is at least one norbornene compound represented by the following general formula [I].

(In the formula [I], n is an integer of 0 to 10, R ¹ is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R ² is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. .) The rubber composition according to claim 1 or 2 , wherein the resin component in the rubber composition is only an ethylene / α-olefin / non-conjugated polyene copolymer [A]. Carbon black [B] is iodine adsorption amount 15~40mg / g, an average particle diameter of 40 to 100 nm, more of claims 1 to 3 for DBP absorption and satisfies the 40~150cm ³ / 100g A rubber composition according to any one of the above. Fuel cell sealing member comprising a rubber composition according to any one of claims 1-4. A fuel cell having a fuel cell sealing material comprising the rubber composition according to any one of claims 1 to 4 . The hard disk drive top cover gasket comprising the rubber composition according to any one of claims 1-4. A gasket material for LIM molding comprising the rubber composition according to any one of claims 1 to 4 . Hard disk drive with the hard disk drive top cover gasket comprising the rubber composition according to any one of claims 1-4. The sealing material for electric wire connectors which consists of a rubber composition in any one of Claims 1-4 . The electric wire connector which has a sealing material for electric wire connectors which consists of a rubber composition in any one of Claims 1-4 . Electric wire connector according to claim 1 1, characterized in that the electric wire connector for automobiles.

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