JPH01108238A - Heat-resistant rubber composition containing surface-treated silica - Google Patents

Abstract

PURPOSE:To obtain a rubber composition which can be crosslinked by heating to give a product excellent in mechanical properties, thermal aging resistance and electrical properties, by mixing an ethylene/alpha-olefin copolymer rubber with a silica filler pretreated with a specified silane compound. CONSTITUTION:This heat-resistant rubber composition is formed by mixing 100pts.wt. ethylene/alpha-olefin copolymer rubber (A) with 10-100pts.wt. silica filler (B) pretreated with a silane compound of the formula (wherein R<1> is an alkenyl or a chloroalkenyl, and R<2> is a lower alkyl). The amount of said silane coupling agent used in the treatment is in the range of, usually, 0.1-5wt.%, preferably, 1-3wt.% (in terms of the amount of carbon) based on the treated filler. The total amount of said components (A) and (B) used in the rubber composition is usually 60wt.% or above, especially, 80wt.% or above, though it may vary according to the purpose of use, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a rubber composition that is crosslinked by heating and provides excellent mechanical properties, heat aging resistance, and electrical properties.

(Prior art and its problems) Ethylene/α-olefin copolymer rubber has mechanical properties,
As a rubber with excellent electrical insulation properties, it is used in automobile parts, electrical parts, general industrial parts, etc. However, recently there have been cases where even higher heat aging resistance is required for automobile parts, electrical parts, etc.

For this reason, attempts have been made to add anti-aging agents to this type of rubber, as seen in the synthetic rubber processing technology encyclopedia ``Ethylene-Propylene Rubber'', but the improvement effect has not been sufficient.

Furthermore, ethylene/α-olefin copolymer rubbers to which silica fillers have been added have been used for various rubber applications. In particular, it is known that when a silica filler is surface-treated with trimethylchlorosilane, etc., it becomes hydrophobic, and such silane-treated silica fillers can also be used in ethylene/α-olefin copolymer rubber. It is blended into.

Although these formulations have excellent initial physical properties, they still have insufficient heat aging resistance.

Therefore, the technical object of the present invention is to significantly improve the heat aging resistance of ethylene/α-olefin copolymer rubber without impairing its excellent mechanical properties and electrical insulation properties.

(Means for Solving the Problems) The surface-treated silica-containing heat-resistant rubber composition of the present invention has the following general formula: OR' ■ R' -S i -OR' .
(I) R2 where R1 represents an alkenyl group, chloroalkenyl group or chloroalkyl group, preferably for example an allyl group, a vinyl group or a chloropropyl group, and R2 represents a lower alkyl group. This method is characterized in that a silica-based filler that has been treated with water is blended into an ethylene/α-olefin copolymer rubber.

(Function) In the present invention, by blending a silica filler treated with a specific silane coupling agent represented by the general formula (I) into an ethylene/α-olefin copolymer rubber, the heat aging resistance of the rubber can be improved. performance is significantly improved.

That is, as is clear from the Examples described below, the composition of the present invention has a retention rate of about 70% in a test at 180°C for 96 hours.
The superiority of the composition of the present invention is demonstrated by the fact that ordinary heat resistance tests are conducted at a temperature of 140°C, and when it shows a value of 70% or more, it can be said that it is a heat-resistant formulation. be understood.

The reason why the heat aging resistance is significantly improved in the present invention is not yet clear, but it is due to the fact that the interface between the filler and the ethylene/α-olefin copolymer rubber is significantly improved. It seems to be.

(Preferred embodiment of the invention) (A) Tamarinieni! The ethylene/α-olefin copolymer rubber used as the base polymer in the composition of the invention includes ethylene and α-olefins such as propylene, 1-butene, 1-pentene,
It is a copolymer with one or more α-olefins having 3 to 10 carbon atoms such as 1-hexene, 4-methyl-1-pentene, 1-octene, and 1-decene. The ethylene content is generally 50 to 95 mol%, preferably 60 to 92 mol%.
within the range of

Furthermore, this ethylene/α-olefin copolymer rubber contains 1
f! The above polyene components may be contained.

Specifically, the polyene component includes 1,4-hexadiene, 1,6-octadiene, 2-methyl-1,5-hexadiene, 6-methyl-1,5-heptadiene, 7-methyl-1,6- quenched nonconjugated dienes, such as octadiene,
Cyclohexadiene, dicyclopentadiene, methyltetrahydroindene, 5-vinylnorbornene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 5-isopropylidene-2-norbornene,
Cyclic non-conjugated dienes such as 6-chloromethyl-5-isopropenyl-2-norbornene, 2,3-diisopropylidene-5-norbornene, 2-ethylidene-3-isopropylidene-5-norbornene, 2-propenyl- 2
, 2-norbornadiene, 1.3.7-octatriene, and 1.4.9-decatriene. Suitable polyenes are cyclic non-conjugated dienes and 1,4-hexadiene, especially dicyclopentadiene or 5-ethylidene-2-norbornene. These polyene components are copolymerized so that the resulting copolymer has an iodine value of at most 30, preferably 20 or less.

These copolymer rubbers generally have an intrinsic viscosity [η] of 0.5 to 4.0 dl/g when measured in decalin at 135°C.
In particular, those in the range of i, o to 3.5 df/g are preferably used.

If this intrinsic viscosity [η] is smaller than the above range,
The resulting rubber composition will have unsatisfactory mechanical properties, and if it is larger than the above range, processability will tend to be impaired.

Furthermore, the above-mentioned ethylene/α-olefin copolymer rubber is
It is also possible to graft copolymerize unsaturated carboxylic acids or derivatives thereof (for example, anhydrides and esters) for use.

The unsaturated carboxylic acids, their anhydrides, and their esters to be graft copolymerized with the above-mentioned ethylene/α-olefin copolymer comb are not limited thereto, but for example, the following can be used.

Unsaturated carboxylic acids nialic acid, methacrylic acid, maleic acid, fumaric acid,
Itaconic acid, citraconic acid, tetrahydrophthalic acid, bicyclo(2,2,1)hept-2-j-cy-5,6-dicarboxylic acid and the like.

Unsaturated carboxylic acid anhydride; maleic anhydride, itaconic anhydride, citraconic anhydride,
Tetrahydrophthalic anhydride, bicyclo(2,2,1)hept-2-ene-5,6-dicarboxylic anhydride, and the like. Among these, maleic anhydride is preferred.

Unsaturated carboxylic acid esters; methyl acrylate, methyl methacrylate, dimethyl maleate, monomethyl maleate, diethyl fumarate,
Dimethyl itaconate, diethyl citraconate, dimethyl tetrahydrophthalate anhydride, dimethyl bicyclo(2,2,1)hept-2-nin-5,6-dicarboxylate, and the like. Among these, methyl acrylate and ethyl acrylate are preferred.

The graft copolymerized carmer such as the above-mentioned unsaturated carboxylic acid is
Each may be used alone or in combination of two or more, but in either case, the amount is 0.1 mol or less, preferably 0, per 100 g of the above-mentioned ethylene/α-olefin copolymer rubber.
．． The amount of grafting is preferably 0.05 mol or less, most preferably 0.01 mol or less.

If the amount of grafting is greater than the above range, the resulting rubber composition tends to be unsatisfactory in processability and cold resistance.

Graft copolymerization is obtained by reacting the aforementioned ethylene/α-olefin copolymer rubber with an unsaturated carboxylic acid or the like in the presence of a radical initiator.

The reaction can be carried out in a solution or in a molten state. When carrying out the process in the molten state, it is most efficient to carry out the process continuously in an extruder.

The radical initiator used in the grafting reaction has a decomposition temperature of 150 to 270°C so that the half-life is 1 minute.
Those within this range are preferably used.

Specifically, organic peroxides, organic bersesters such as benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(peroxybenzoate) hexyne-3,1 ,4-bis(te
rt-butylperoxyisopropyl)benzene, lauroylheloxide, tert-butylberacetate, 2,5-dimethyl-2,5-di(tart-butylperoxy)hexyne-3,2,5-dimethyl-2,5-
di(tert-butylperoxy)hexane, tert
-butylberbenzoate, tert-butylberphenylacetate, tert-butylberisobutyrate, tert-butylber-5ec-octoate, te
Mention may be made of rt-butylberbivalate, cumylberbivalate and tert-butylberdiethyl acetate.

The above-mentioned ethylene/α-olefin copolymer rubber has a Mooney viscosity (M
L l-4 (100°C) is 5 to 180, especially 10
Those in the range of 120 to 120 are preferably used.

(B) Silane treatment Silica-based soil material In the present invention, the following formula (I) is used as the silane coupling agent for silane treatment of the silica-based filler. ... (I
)■ R2 In the formula, R1 represents an alkenyl group, a chloroalkenyl group, or a chloroalkyl group, preferably an allyl group, a vinyl group, or a chloropropyl group, and R2 represents a lower alkyl group, such as a methyl group or an ethyl group. A silane compound represented by the following formula is used. Specifically, but not limited to, allyltrimethoxysilane, allyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, chloropropyltrimethoxysilane, chloropropyltriethoxysilane, etc. can be mentioned.

Further, as the silica filler to be treated, all known ones can be used, and for example, dry silica, wet silica, synthetic silicate white carbon, talc, clay, etc. are preferably used.

The treatment amount of the silane coupling agent represented by the general formula (1) is 0.1 to 5% by weight, preferably 0.5 to 4% by weight, most preferably 0.5 to 4% by weight based on the treated filler. The content is preferably in the range of 1 to 3% by weight.

If the amount treated is too small, the desired heat aging resistance will not be achieved, while if it is used in too large a quantity, it will only be economically disadvantageous.

The use of such a silane-treated silica filler not only significantly improves the heat aging resistance of the rubber composition, but also increases the cavity specific gravity of the filler, which reduces the possibility of ethylene/α-olefin copolymerization. It can be kneaded smoothly with rubber and has great industrial significance.

The treatment with a silane coupling agent can be carried out by means known per se.

That is, a method of reacting a silica-based filler and a silica compound in a treatment chamber consisting of an upright tubular furnace by a continuous parallel flow method, as seen in Japanese Patent Publication No. 17049/1983;
Alternatively, there may be mentioned a method as disclosed in Japanese Patent Publication No. 8379/1983, in which a silica filler and a silica compound are brought into contact at a relatively low temperature, then treated at a high temperature, and further dried with an inert gas.

The carbon content of the silane-treated silica filler was measured as follows. That is, the silane-treated silica filler was sufficiently dried at 150° C. while flowing nitrogen gas, and then the carbon content was measured using an elemental analyzer.

The rubber composition of the present invention includes 100 parts by weight of ethylene/α-olefin copolymer rubber (A) and 10 parts by weight of a silica filler treated with a specific silane coupling agent or a mixture (B). It is blended in an amount of 100 parts by weight, preferably 15 to 80 parts by weight, more preferably 20 to 60 parts by weight.

If the amount of silica-based filler treated with a silane coupling agent is less than the above range, or if it is too much, the desired strength cannot be obtained and it is not practical.

Compounding agents The rubber composition of the present invention may contain compounding agents known per se, such as rubber reinforcing agents, softeners, vulcanizing agents, vulcanization aids, etc., depending on the intended use of the vulcanizate. can do.

In this case, the total amount of the components (^) to (B) in the composition is generally 60% by weight, although it varies depending on the use etc.
In particular, it is preferable that the content be 80% by weight or more.

Rubber reinforcing agents that can be used include SRF, GPF, and F.
Carbon blacks such as EF, HAF, 15AF, SAF, FT, and MT are exemplified.

These reinforcing agents for rubber can be selected as appropriate depending on the intended use, but the total amount of the components (A) and (B) mentioned above is 100%.
The amount per part by weight is preferably 50 parts by weight or less, particularly 30 parts by weight or less.

The softening agent that can be used in the present invention is usually a softening agent used for rubber, but examples include process oil, lubricating oil, synthetic lubricating oil, paraffin, liquid paraffin, petroleum asphalt, petroleum-based softeners such as petrolatum, coal Coal tar-based softeners such as tar and coal tar pitch; fatty oil-based softeners such as castor oil, linseed oil, rapeseed oil, and coconut oil; tall oil; sub; waxes such as beeswax, carnauba wax, and lanolin; ricinoleic acid , balmitic acid, barium stearate, calcium stearate, zinc laurate, and other fatty acids and fatty acid salts; petroleum resins, atactic polypropylene, coumaron indene resins, polyester resins, and other synthetic polymers, or dioctyl adipate, dioctyl adipate, etc. Examples include ester plasticizers, microcrystalline waxes, and sub(factices).

The amount of these softeners can be selected as appropriate depending on the intended use, but the total amount of the components (^) to (B) mentioned above is 10%.
It is preferably 50 parts by weight or less, particularly 30 parts by weight or less per 0 parts by weight.

The vulcanized product from the composition of the present invention is produced by preparing an unvulcanized compounded rubber by the method described below, and then molding the compounded rubber into the intended shape, in the same way as when vulcanizing general rubber. Manufactured by post-vulcanization. As a vulcanization method, there are a method of heating using a vulcanizing agent and a method of irradiating with an electron beam.

Examples of the vulcanizing agent used include sulfur compounds and organic peroxides. Examples of the sulfur-based compound include sulfur, sulfur chloride, sulfur dichloride, morpholine disulfide, alkylphenol disulfide, tetramethylthiuram disulfide, and selenium dimethyldithiocarbamate, among which sulfur is preferably used. The sulfur compound is used in an amount of 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, per 100 parts by weight of the modified ethylene/α-olefin copolymer rubber (A). Examples of organic peroxides include dicumyl peroxide, 2,5-dimethyl-2,.5-di(tert-butylperoxy)hexane, and 2,5-dimethyl-2.
, 5-di(benzoylperoxy)hexane, 2.5-
Examples include dimethyl-2゜5-di(tert-butylperoxy)hexyne-3, di-tert-butyl peroxide, di-tert-butyl peroxy-3,3,5-trimethylcyclohexane, and tert-butyl hydroperoxide. Dicumyl peroxide, di-tert-butyl peroxide and di-tert-butyl peroxide-3,3°5-trimethylcyclohexane are preferably used. The organic peroxide is used in an amount of 3X10-' to 5X10-2 moles, preferably 1X10-3 to 3X10-' moles, per 100 parts by weight of the ethylene/α-olefin copolymer rubber (A).

When using a sulfur compound as a vulcanizing agent, it is preferable to use a vulcanization accelerator in combination. As a vulcanization accelerator, N-cyclohexyl-2-penzothiazole-sulfenamide, N
-oxydiethylene-2-benzothiazole-sulfenamide, N,N-diisopropyl-2-benzothiazole-sulfenamide, 2-mercaptobenzothiazole, 2-(2,4-dinitrophenyl)mercaptobenzothiazole, 2-( Thiazole series such as 2,6-ethyl-4-morpholinothio)benzothiazole and dibenzothiazyl-disulfide; guanidine series such as diphenylguanidine, triphenylguanidine, diorthotolylguanidine, orthotolyl pi-guanide, and diphenylguanidine phthalate; Acetaldehyde
Aniline reactant, butyraldehyde-aniline condensate,
Aldehyde amines or aldehyde-ammonia such as hexamethylenetetramine and acetaldehyde ammonia; imidacillins such as 2-mercaptoimidacillin; thiocarbamic acid, diethylthiourea, dibutylthiourea, trimethylthiourea, diorthotolylthiourea Thiourea series: Thiuram series such as tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, pentamethylenethiuram tetradrasulfide, zinc dimethyldithiocarbamate, zinc diethylthiocarbamate, di-n-butyl Dithioate salts such as zinc dithiocarbamate, zinc ethyl phenyl dithiocarbamate, zinc butylphenyl dithiocarbamate, sodium dimethyl dithiocarbamate, selenium dimethyl dithiocarbamate, tellurium diethyldithiocarbamate; Santate systems such as zinc dibutyl xanthate; others, Examples include zinc oxide. These vulcanization accelerators are used in an amount of 0.1 to 20 parts by weight, preferably 0.2 to 10 parts by weight, per 100 parts by weight of the ethylene/α-olefin copolymer rubber (A).

When using an organic peroxide as a vulcanizing agent, it is preferable to use a vulcanizing aid in combination. Examples of vulcanization aids include sulfur, quinone dioxime types such as p-quinone dioxime, methacrylate types such as polyethylene glycol dimethacrylate, allyl types such as diallyl phthalate and triallyl cyanurate, other maleimide types, and divinylbenzene. be done. Such a vulcanization aid is the organic peroxide used.
It is used in a range of 1 to 2 moles, preferably about equal moles.

When the vulcanization method does not use a vulcanizing agent and uses an electron beam, the molded unvulcanized compounded rubber described below is charged with 0.1 to 10 MeV (megaelectron volt), preferably 0.3 to 2. The absorption line for electrons with energy of QMeV is 0.5 to 35 Mrad (megarad),
It is preferable to irradiate at 0.5 to 10 Mrad. At this time, a vulcanization aid may be used in combination with the organic peroxide as the vulcanizing agent, and the amount thereof is lXl0-' to lXl0 with respect to 100 parts by weight of the ethylene/α-olefin copolymer rubber (A). -' molar parts, preferably 1X10-' to 3X10-' molar parts.

Furthermore, the composition of the present invention may contain colorants, anti-aging agents,
Dispersants and flame retardants can be added.

ヱA11ll Th+7) An unvulcanized compounded rubber manufactured by iPtl is prepared by the following method. That is, using a mixer such as a Banbury mixer, the ethylene/α-olefin copolymer rubber (A), the silica filler (B) treated with the silane coupling agent of formula (I), and if necessary for rubber After kneading the reinforcing agent and the softening agent at a temperature of 80 to 170°C for 3 to 10 minutes, the vulcanizing agent and, if necessary, the vulcanization accelerator or vulcanization aid are added using rolls such as oven rolls. Additional mixing, roll temperature 40-80℃
After kneading for 5 to 30 minutes, the mixture is separated to prepare a ribbon-like or sheet-like compounded rubber.

The compounded rubber thus prepared is molded into the intended shape using an extruder, calendar roll, or press,
A vulcanized product can be obtained simultaneously with molding, or by introducing the molded product into a vulcanization tank and heating it at a temperature of 150 to 270° C. for 1 to 30 minutes, or by irradiating it with an electron beam by the method described above. This vulcanization step may be carried out using a mold or without a mold. When a mold is not used, the molding and vulcanization steps are usually carried out continuously.

Of course, when vulcanization is performed by electron beam irradiation, a compounded rubber containing no vulcanizing agent is used.

Further, as a heating method in the vulcanized layer, a heating layer such as hot air, glass beads fluidized bed, U) IF (ultra-high frequency electromagnetic wave), steam, etc. can be used.

(Effects of the Invention) As shown in the examples below, the rubber composition of the present invention thus produced has excellent mechanical properties, electrical insulation properties, and heat aging resistance, and can be used for wire sheathing, tubes, belts, rubber rolls, Suitable for use in gaskets, packings, rubber hoses, etc.

The excellent effects of the present invention will be explained with the following example.

(Example) A rubber composition was prepared according to the following recipe using the following as the ethylene/α-olefin copolymer rubber (A) and the silane-treated silica filler.

・Ethylene/α-olefin copolymer rubber (A) Ethylene content = 68 mol% α-olefin: Propylene [η): 1.8 Iodine value: 5 (ethylidenenorbornene) ・Silan-treated silica (B) Formula ethylene・α -Olefin copolymer rubber 100.
0 parts by weight silane-treated silica 30.0)
) Stearic acid 2. o Zinc white
5. o Organic peroxide 11
5. Q ll sulfur 0
．． 2〃Anti-aging agent M B') 2.0!
Part Antioxidant 200"'1.0 11 Kneading was carried out at 60°C to 70°C for 20 minutes using an 8-inch oven roll. The mixture was then press-vulcanized at 170°C for 10 minutes to form a 2 mm thick A vulcanized rubber sheet was prepared and subjected to measurements.All measurements were conducted in accordance with the method of JIS K 6301, and the following items were measured.

Normal state properties Tensile strength (TB), elongation (EB), heat aging resistance [Heat aging conditions: 180°C - 96 hours tensile strength retention rate A R (T B), elongation retention rate A R (E B) Results are shown in Table 1 below.

Dog A■-U Example 1 was carried out in exactly the same manner as in Example 1, except that the following ethylene/α-olefin copolymer rubber was used.

Ethylene content: 80 mol% α-olefin: Propylene [η): 1.5 Same as Example 1 except that the following was used as the ethylene/α-olefin copolymer rubber in Example 1. went.

Ethylene content: 2 80 mol% α-olefin: Propylene (η): 1.5 The same procedure as in Example 1 was conducted except that the following ethylene/α-olefin copolymer rubber was used.

Ethylene content = 90 mol% α-olefin = 1-butene (η) 7 1.3 Comparative Example 1 The same procedure as in Example 1 was carried out except that untreated silica was used instead of the silane-treated silica in Example 1. Ta.

Group 1-2 The same procedure as in Example 1 was carried out except that the following silane-treated silica was used in Example 1.

Example 6 The same procedure as in Example 1 was conducted except that the following was used as the silane-treated silica.

Silane cup: Allyl trimetrating agent
Xysilane Example 1 was carried out in exactly the same manner as in Example 1, except that the amount of silane-treated silica treated was 0.5 wt% in terms of carbon content.

Uprighting - The procedure was carried out in exactly the same manner as in Example 1, except that the silane-treated silica was treated and buried at a carbon content of 3.5 wt%.

Example 9 The same procedure as in Example 1 was conducted except that the ethylene/α-olefin copolymer rubber was modified with maleic anhydride and used as the ethylene/α-olefin copolymer rubber in Example 2.

Content of maleic anhydride for 1 oo3 of ethylene/α-olefin copolymer rubber: 5X1
Example 9 was carried out in exactly the same manner as in Example 9, except that the silanized silica shown below was used.

Example 9 was carried out in exactly the same manner as in Example 9, except that the silane-treated silica shown below was used.

The same procedure as in Example 4 was conducted except that the ethylene/α-olefin copolymer rubber was modified with ethyl acrylate and used as the ethylene/α-olefin copolymer rubber.

Ethyl acrylate content per 100 g of ethylene/α-olefin copolymer rubber: 10-2 mol% 2 Kfl-Eyu In Example 1, the following was used as the ethylene/α-olefin copolymer rubber, and the compounding recipe was as follows. The same procedure as in Example 1 was carried out except for the following.

・Ethylene/α-olefin copolymer rubber ethylene content
: 70 mol% α-olefin: Propylene [η) : 2.7 Iodine value = 10 (ethylidene norbornene) Formula ethylene/α-olefin copolymer rubber 100.0
Part by weight Silane-treated silica 30. On stearic acid 2.0 Zinc white
5.0 Accelerator DPTT”
0.5 parts by weight Accelerator ZnBDC” 1.5
tt accelerator MBTS” 3.0 1) Sulfur 1.5 Anti-aging agent AAN
P” 1.0) 1 foot:
Manufactured by Ouchi Shinkosha 2 Manufactured by Ohmukai Shinkosha Example 1 except that the formulation in Example 1 was as follows.
I did the same thing.

Blending recipe Ethylene/α-olefin copolymer rubber 100.0
Part by weight Silane treated silica 15. Ott
Stearic acid 2.0 Zinc white
5.0 parts by weight organic peroxide! 1
5, Q tt sulfur
0.2〃Anti-aging agent MB” 2.On
Anti-aging agent 200" 1.0 The same procedure as in Example 1 was carried out except that the formulation was changed as follows.

Blending recipe Ethylene/α-olefin copolymer rubber 100.0 parts by weight Silane-treated silica 50. On stearic acid 2,0〃synthetic lubricating oil”
20.0 11 Zinc white
5.0 Organic peroxide 5.0 Sulfur
0.2〃Anti-aging agent M, B
2. Qn anti-aging agent 200
1.0) 11) Trade name Lucant HC-600: Made by Mitsui Petrochemical Co., Ltd. The same procedure as in Example 1 was carried out except that the following was used as the silanized silica.

・Silane treated silica Silica: Product name Nibsil VN.

Silane Cup: Rilorobrobilt Ring Agent Rimethoxysilane Comparative Example 2 The same procedure as in Example 16 was carried out except that the formulation was changed as follows.

Combined formulation: Ethylene and α-olefin! Synthetic rubber 100.
0 parts by weight Silanized silica 5.0 Stearic acid 2. O Zinc white
5.0 Organic peroxide 5
．． 0. Sulfur 0.2 parts by weight Antioxidant MB 2. On anti-aging agent 20
0 1. On Comparative Example 3 The same procedure as in Example 16 was conducted except that the formulation was changed as follows.

Combination prescription

Claims (6)

[Claims] (1) (A) Ethylene/α-olefin copolymer rubber 10
(B) The following general formula ▲ Numerical formulas, chemical formulas, tables, etc. are included ▼... (I) In the formula, R^1 is an alkenyl group, chloroalkenyl group, or chloroalkyl group, and R^2 is lower alkyl 10 to 100 parts by weight of a silica-based filler pretreated with a silane compound represented by the group: 10 to 100 parts by weight of a heat-resistant rubber composition containing surface-treated silica. (2) The silane-treated silica filler (B) is treated with a silane compound represented by the general formula (I) so that the carbon content is 0.1 to 5.0% by weight. A rubber composition according to claim 1. (3) Ethylene/α-olefin copolymer rubber (A) is
The intrinsic viscosity [η) measured in decalin at 135°C is 0.
5. The rubber composition according to claim 1, wherein the rubber composition is in the range of 4.0 dl/g. (4) The composition of the ethylene/α-olefin copolymer rubber (A) is ethylene/α-olefin = 50/50 in molar ratio
The rubber composition according to claim 1, which has a rubber composition of 95/5 to 95/5. (5) Ethylene/α-olefin copolymer rubber (A) is
The rubber composition according to claim 1, which contains a non-conjugated polyene having an iodine value of at most 30. (6) Ethylene/α-olefin copolymer rubber (A) is
Modified ethylene/α- which is obtained by graft copolymerizing up to 10^-^1 mole of one or more compounds selected from unsaturated carboxylic acids, their acid anhydrides, and their esters per 100 g of ethylene/α-olefin copolymer rubber. The rubber composition according to claim 1 or 2, which is an olefin copolymer rubber.