JP3480131B2 - Crosslinkable rubber composition - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a crosslinkable rubber composition containing an ethylene / α-olefin / diene copolymer rubber as a base polymer.

[0002]

2. Description of the Related Art Ethylene / α-olefin / diene copolymer rubber is a rubber excellent in heat aging resistance, cold resistance and weather resistance, but further improvement in abrasion resistance is desired. Therefore, in order to improve wear resistance, measures such as blending of carbon black having a small particle size or increasing the degree of crosslinking have been taken. However, when carbon black having a small particle size is blended, the product becomes hard, and when the degree of crosslinking is increased, the elongation elongation becomes small.

On the other hand, in recent years, there is a strong demand for rubber products with even higher performance, mainly in the automobile field, and they have excellent wear resistance, low hardness, large elongation, and excellent cold resistance. The advent of rubber products is desired.

By the way, in JP-A-7-48478, in order to improve the processability (plasticity) of a polarizable crosslinkable rubber such as chloroprene rubber and chlorinated polyethylene, two alkyl groups having 1 to 36 carbon atoms are used. A crosslinkable rubber-like composition having a long-chain alkyl carbonate, which has at least one alkyl group and is a linear or branched alkyl group having 6 to 36 carbon atoms, is described. However, since such a long-chain alkyl carbonate does not have good compatibility with the non-polar ethylene / α-olefin / diene copolymer rubber, it is necessary to improve the processability of the ethylene / α-olefin / diene copolymer rubber. It is considered that it is not necessarily suitable as a plasticizer, and is not exemplified as a usable rubber in the above publication.

[0005]

DISCLOSURE OF THE INVENTION The object of the present invention is to achieve cross-linking which is excellent in abrasion resistance, low in hardness, large in elongation and excellent in cold resistance in order to meet the recent demand for higher performance of rubber products. To provide a rubber composition.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have added and compounded a specific alkyl carbonate to an ethylene / α-olefin / diene copolymer rubber, and The present invention has been completed by finding that the obtained rubber product is excellent in the above-mentioned various properties.

That is, the present invention is the following crosslinkable rubber composition. (1) 15 to 160 parts by weight of a long-chain alkyl carbonate represented by the following general formula (1) per 100 parts by weight of (A) ethylene / α-olefin / diene copolymer rubber. A crosslinkable rubber composition. R ¹ OCOOR ² ... (1) (wherein R ¹ and R ² are the same or different,
A linear or branched alkyl group having 10 to 20 carbon atoms, a cycloalkyl group, or an alkyl group containing a cycloalkyl group, wherein at least one of R ¹ and R ² is a direct alkyl group having 10 to 20 carbon atoms. It is a chain or branched alkyl group. (2) The ethylene / α-olefin / diene copolymer rubber (A) has an α-olefin having a carbon number of 3 to 30, and an ethylene / α-olefin molar ratio of 55/45 to 85/1.
5. Mooney viscosity [ML _{1 + 4} (100 ° C)] is 5-40
0, the crosslinkable rubber composition according to (1) above, having an iodine value of 3 to 40.

The ethylene / α-olefin / diene copolymer rubber (A), which is one component of the rubber composition of the present invention, is used as a base polymer. Ethylene / α
As the α-olefin constituting the olefin / diene copolymer rubber, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene or the like has 3 carbon atoms. ~ 30 can be mentioned. Of these, propylene and 1-butene are preferred.

The ratio of ethylene to α-olefin is such that the ethylene / α-olefin molar ratio is 55/45 to 85/1.
It is desirable that it is 5, preferably 65/35 to 80/20. The Mooney viscosity is [ML _{1 + 4} (100 ° C)], which is 5
It is desirable to be 400 to 400, preferably 10 to 300.

The diene component includes 1,4-hexadiene, 1,6-octadiene, 2-methyl-1,5-hexadiene, 6-methyl-1,5-heptadiene and 7-methyl-1,6-octadiene. Such chain non-conjugated dienes, cyclohexadiene, dicyclopentadiene, methyl tetrahydroindene, 5-vinyl norbornene, 5
-Ethylidene-2-norbornene, 5-methylene-2-
Examples include non-conjugated dienes such as cyclic non-conjugated dienes such as norbornene, 5-isopropylidene-2-norbornene, and 6-chloromethyl-5-isopropenyl-2-norbornene. Among these, cyclic non-conjugated dienes are preferable, and dicyclopentadiene and 5-ethylidene-
2-norbornene is preferred.

In the case of a non-conjugated diene, the content of the diene component is preferably such that the iodine value is in the range of 3-40, preferably 5-30. The ethylene / α-olefin / diene copolymer rubber (A) is a random copolymer rubber obtained by randomly polymerizing the above monomer components.

As the long-chain alkyl carbonate (B) which is the other component of the rubber composition of the present invention, the one represented by the above general formula (1) is used and it is blended as a plasticizer (softening agent). .

Examples of the chain or branched alkyl group having 10 to 20 carbon atoms represented by R ¹ or R ² in the general formula (1) include n- and iso-decyl groups, n- and iso-undecyl groups, n- and iso-dodecyl groups, n- and iso-tridecyl groups, n- and is
o-tetradecyl group, n- and iso-pentadecyl group, n- and iso-heptadecyl group, n- and i
Examples thereof include so-octadecyl group and n- and iso-icosyl groups. In the general formula (1), R
^At least one of ¹ and R ² is a chain or branched alkyl group having 10 to 20 carbon atoms as described above.

Examples of the cycloalkyl group represented by R ¹ or R ² in formula (1) or the alkyl group containing a cycloalkyl group include cyclopentyl group, cyclohexyl group, dicyclopentyl group and tricyclotetradecanyl group. An alkyl group having 10 to 20 carbon atoms including a cycloalkyl group can be mentioned. The long-chain alkyl carbonate (B) is preferably ^one in which R ¹ and R ² are linear or branched alkyl groups having 12 to 15 carbon atoms.

These long-chain alkyl carbonates (B)
Is usually synthesized as follows. The synthesis reactor is
The temperature can be controlled by an external circulating fluid, and in addition, a distillation device equipped with a reflux device at the top, a stirrer and a thermometer are provided in order to selectively distill off the low boiling point fraction produced during the synthesis reaction. A jacketed flask equipped is used. In this flask, a carbonic acid ester (for example, dimethyl carbonate) synthesized by using a low-boiling alcohol as a raw material, and at least a stoichiometric amount, preferably an excess amount of a higher alcohol or higher alcohol mixture and a strongly basic mixture. An organic or inorganic compound type transesterification catalyst is filled.

The mixture is heated while being stirred, heated to the boiling temperature, and the reaction is advanced while removing the low-boiling alcohol produced from the top of the distillation column. In some cases, the reaction is allowed to proceed by facilitating the distillation of the low boiling alcohol in the presence of an inert solvent that forms the lowest azeotrope with the low boiling alcohol. After the completion of the reaction, neutralization and water washing are performed to remove the catalyst, and then unnecessary by-products and unreacted raw materials are distilled off to recover the reaction product in the flask.

Alkyl carbonates of the general formula (1) in which R ¹ or R ^{2 has} a carbon number of less than 10 are ethylene / α
The bleed-out from the olefin / diene copolymer rubber (A) is remarkable and cannot be used in the present invention. On the other hand, R ¹
Alternatively, an alkyl carbonate having a carbon number of R ² of more than 20 does not form a film on the surface of the ethylene / α-olefin / diene copolymer rubber (A), and therefore has excellent wear resistance, low hardness, large elongation, and cold resistance. A rubber composition having excellent properties cannot be obtained.

Next, the crosslinkable rubber composition of the present invention will be described. In the crosslinkable rubber composition of the present invention (hereinafter sometimes simply referred to as a rubber composition), ethylene
The blending ratio of the long-chain alkyl carbonate (B) to the α-olefin / diene copolymer rubber (A) is 100 parts by weight of the component (A) and the long-chain alkyl carbonate (B).
15 to 160 parts by weight is necessary for achieving the object of the present invention, and 15 to 100 parts by weight is more preferable.

When the long-chain alkyl carbonate (B) is more than 15 parts by weight in the above ratio, the desired abrasion resistance is obtained. On the other hand, when the amount is less than 160 parts by weight, the strength characteristics are not significantly deteriorated, so that a desired rubber composition can be obtained. In the present invention, by blending the components (A) and (B) in the above ratio, it is possible to obtain a rubber composition having excellent wear resistance, low hardness, large elongation, and excellent cold resistance.

The ethylene / α-olefin / diene copolymer rubber (A) itself is excellent in heat aging resistance, cold resistance and weather resistance, but the long chain alkyl carbonate (B) is an ethylene / α-olefin / diene copolymer. By combining with the rubber (A), the ethylene / α-olefin / diene copolymer rubber (A) is provided with excellent abrasion resistance while improving the cold resistance as compared with commercially available paraffin oil. Moreover, in this case, unlike the conventionally known methods for improving wear resistance, adverse effects such as an undesired increase in rubber hardness and an undesired decrease in elongation elongation do not occur. Further, it is possible to obtain a vulcanized rubber with a small change in the friction coefficient.

Conventionally, as described above, the alkyl carbonate was considered to be unsuitable as a plasticizer to be blended with the ethylene / α-olefin / diene copolymer rubber because of its insufficient compatibility with the non-polar rubber. , R in the general formula (1)
By blending the above-mentioned long-chain alkyl carbonate (B) having a limited number of carbon atoms of ¹ and R ^{2 in} a specific amount, the abrasion resistance of the ethylene / α-olefin / diene copolymer rubber (A) is improved and friction is improved. The coefficient can be maintained. this is,
Since the long chain alkyl carbonate (B) has an intermediate property between compatibility with ethylene / α-olefin / diene copolymer rubber (A) and phase separation, a small amount of long chain alkyl carbonate (B) is present on the surface. It is presumed that this is because the film is formed by bleeding out. Such wear resistance and maintenance of the friction coefficient are properties that cannot be obtained even if the long-chain alkyl carbonate (B) is mixed with polar rubber such as chloroprene.

The rubber composition of the present invention contains a compounding agent known per se, such as a vulcanizing agent, a vulcanization aid, a rubber reinforcing agent, a pigment, depending on the intended use of the vulcanized product and the performance based on the intended use. A filler, a softening agent, an anti-scorch agent, an anti-aging agent, a processing aid and the like can be added.

The method of crosslinking the rubber composition of the present invention includes:
A known vulcanization method can be adopted, usually, vulcanization with sulfur or a sulfur-based compound, resin vulcanization, quinoid vulcanization,
Vulcanization methods such as organic peroxide vulcanization and electron beam irradiation vulcanization can be adopted. Among these, vulcanization using sulfur or a sulfur-based compound is preferable, and in this case, the performance of the rubber composition of the present invention can be best exhibited.

Specific examples of sulfur or sulfur compounds include sulfur, sulfur chloride, morpholine disulfide, alkylphenol disulfide, tetramethylthiuram disulfide, and selenium dimethyldithiocarbamate. Of these, sulfur is preferably used.
Sulfur or sulfur compounds are ethylene / α-olefin /
0.1 to 100 parts by weight of diene copolymer rubber (A)
It is used in an amount of 10 parts by weight, preferably 0.5 to 5 parts by weight.

When a sulfur compound is used as a vulcanizing agent, it is preferable to use a vulcanization accelerator together. Specific examples of the vulcanization accelerator include N-cyclohexyl-2-benzothiazole sulfenamide, N-oxydiethylene-2-benzothiazole sulfenamide, N, N-
Diisopropyl-2-benzothiazole sulfenamide, 2-mercaptobenzothiazole, 2- (2,4-
Dinitrophenyl) mercaptobenzothiazole, 2-
Thiazole compounds such as (2,6-diethyl-4-morpholinothio) benzothiazole and dibenzothiazyl disulfide; guanidine compounds such as diphenylguanidine, triphenylguanidine, diorsonitrile guanidine, orthonitrile biguanide and diphenylguanidine phthalate An acetaldehyde-aniline reaction product,
Butyraldehyde-aniline condensates, aldehyde amines such as hexamethylenetetramine, acetaldehyde ammonia, or aldehyde-ammonia compounds; imidazoline compounds such as 2-mercaptoimidazoline; thiocarbanilide, diethylthiourea, dibutylthiourea, trimethylthiourea, diortho Thiourea compounds such as tolylthiourea; tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, thiuram compounds such as pentamethylenethiuram tetrasulfide; zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, Zinc di-n-butyldithiocarbamate, zinc ethylphenyldithiocarbamate, butyrate Zinc phenyl dithiocarbamate,
Examples thereof include dithioate-based compounds such as sodium dimethyldithiocarbamate, selenium dimethyldithiocarbamate, and tellurium dimethyldithiocarbamate; xanthate-based compounds such as zinc dibutylxanthate; zinc white. These vulcanization accelerators are used in an amount of 0.1 to 20 parts by weight, preferably 0.2 to 10 parts by weight, based on 100 parts by weight of the ethylene / α-olefin / diene copolymer rubber (A).

The rubber composition of the present invention includes SRF and GP.
Carbon black such as F, FEF, HAF, ISAF, SAF, FT, MT; rubber reinforcing material such as finely powdered silicic acid; light calcium carbonate, heavy calcium carbonate, talc, clay, silica, etc. Good. These reinforcing materials or fillers can be blended alone or in combination of two or more kinds. The type and blending amount of the rubber reinforcing material and the filler can be appropriately selected depending on the application, but usually ethylene / α-olefin / diene copolymer rubber (A) 1
The maximum amount is 300 parts by weight, preferably the maximum amount is 200 parts by weight, relative to 00 parts by weight.

As the softening agent, the specific long-chain alkyl carbonate (B) of the present invention is used, but if necessary, other existing softening agents may be used in combination. Other softeners that can be used in combination include, for example, petroleum-based substances such as process oil, lubricating oil, paraffin, liquid paraffin, petroleum asphalt, and petrolatum; coal tars such as coal tar and coal tar pitch; castor oil, rapeseed oil, Fatty oils such as soybean oil and coconut oil; tall oil, beeswax, carnauba wax,
Waxes such as lanolin; fatty acids such as ricinoleic acid, palmitic acid, stearic acid, barium stearate, calcium stearate or metal salts thereof; naphthenic acid or metal soap thereof; pine oil, rosin or its derivatives,
Ester plasticizers such as terpene resin, petroleum resin, coumarone resin, atactic polypropylene, dioctyl phthalate, dioctyl adipate, dioctyl sebacate; other microcrystalline wax, sub (factice), liquid polybutadiene, modified liquid polybutadiene, liquid thiocol It can be illustrated.

These other softening agents may be blended alone or in combination of two or more. The blending amount of the other softening agent is appropriately selected depending on the desired product, but in any case, ethylene / α-olefin / diene copolymer rubber (A) 10
The amount is usually 100 parts by weight or less, preferably 70 parts by weight or less, based on 0 parts by weight.

As the anti-scorch agent, known anti-scorch agents can be used, and examples thereof include maleic anhydride, thioimide compounds, sulfenamide compounds and sulfonamide compounds. These anti-scorch agents may be blended alone or in combination of two or more. The content of the scorch inhibitor is usually 0.2 to 5 parts by weight, preferably 0.3 to 3 parts by weight, based on 100 parts by weight of the ethylene / α-olefin / diene copolymer rubber (A). To be

Further, the rubber composition of the present invention exhibits excellent heat resistance and durability without the use of an antioxidant, but it is also possible to improve the durability by using an antioxidant. It is similar to the case of the thing. Known anti-aging agents can be used in this case,
For example, aromatic secondary amines such as phenylbutylamine, N, N'-di-2-naphthyl-p-phenylenediamine; dibutylhydroxytoluene, tetrakis [methylene (3,5-di-t-butyl-4-hydroxy)] Phenolic stabilizers such as hydrocinnamate] methane; Thioether stabilizers such as bis [2-methyl-4- (3-n-alkylthiopropionyloxy) -5-t-butylphenyl] sulfide; Nickel dibutyldithiocarbamate The dithiocarbamate-based stabilizer and the like can be exemplified. These anti-aging agents may be used alone or in 2
It is possible to mix and combine one or more species. The antioxidant is usually 0.1 to 5 parts by weight with respect to 100 parts by weight of the ethylene / α-olefin / diene copolymer rubber (A),
Preferably 0.5 to 3 parts by weight is used.

As the processing aid, those used in the processing of ordinary rubber can be used. Ricinoleic acid, stearic acid, palmitic acid, lauric acid, barium stearate, calcium stearate, zinc stearate and the above-mentioned acids. Examples thereof include higher fatty acids, salts thereof and esters thereof. These processing aids can be blended alone or in combination of two or more. The mixing amount of the processing aid is usually up to about 10 parts by weight, preferably about 1 to 5 parts by weight, based on 100 parts by weight of the ethylene / α-olefin / diene copolymer rubber (A).

Further, a pigment is used depending on the product. As the pigment, known inorganic pigments (for example, titanium white) and organic pigments (for example, naphthol green B) are used. The amount of these pigments used varies depending on the product, but a maximum amount of 20 parts by weight, preferably 10 parts by weight or less is used.

The rubber composition of the present invention can be prepared, for example, by the following method. That is, ethylene / α-olefin / diene copolymer rubber (A) and long-chain alkyl carbonate (B), which are essential components of the present invention, and additives such as a reinforcing agent, a filler, a softening agent, and a pigment that are blended as necessary. Is kneaded at a temperature of about 80 to 170 ° C. for about 3 to 10 minutes using a mixer such as a Banbury mixer, and then a vulcanizing agent and a vulcanization aid are additionally mixed using rolls such as an open roll, About 3 at a roll temperature of about 40-80 ° C
The mixture is kneaded for about 30 minutes and parted to prepare a ribbon-shaped or sheet-shaped rubber composition.

The unvulcanized rubber compound thus prepared is molded into a desired shape by, for example, an extruder, a calender roll, a press or the like, and the molded product is molded at the same time or in a vulcanization tank. Usually about 1 at about 150-270 ℃
It is vulcanized by a method of heating for 30 minutes. As the vulcanizing tank, a steam vulcanizing can, a hot air heating tank, a fluidized bed of glass beads, a molten salt vulcanizing tank, a microwave vulcanizing tank, etc. may be used alone or in combination.

Suitable applications of the rubber composition of the present invention include rolls for OA, electric insulating materials, automobile parts, rubber products for industrial use, civil engineering materials, rubberized cloth, and the like. As the OA roll, a paper feed roll, a platen roll, a fixing roll, a pressure roll, an oil supply roll and the like can be used. As electric insulating materials, plugs, ignition caps, distributor caps and other caps around automobile engines; capacitor caps, marine electric wires, insulation layers coated in a cylindrical shape on the conducting parts of electric wires such as automobile ignition cables; cable joints It can be used as a cover.

As the automobile parts, radiator hose,
Hoses such as fuel hoses; bumpers, bumper fillers, bumper strips, bumper side guards,
It can be used for automobile exterior parts such as overriders and side protection moldings; other various weather strips, boots, ball joint seals, various anti-vibration rubbers, etc.

As an industrial rubber product, it can be used for rolls, packing, linings, belts and the like. For civil engineering materials, it can be used for roofing sheets, heat resistant belts, building material gaskets, highway joint seals, etc. As a rubberized cloth, it can be used for waterproof cloth, awnings, leisure sheets, etc. Further, a foamed vulcanizate that can be used as a heat insulating material, a cushioning material, a sealing agent, a soundproofing material, an electric insulating material, etc. by compounding a foaming agent and a foaming auxiliary agent if necessary in a rubber compound prior to vulcanization. Can also be

[0038]

The crosslinkable rubber composition of the present invention comprises an ethylene / α-olefin / diene copolymer rubber (A) and a specific long-chain alkyl carbonate (B) as essential components, and a nonpolar ethylene / α -Olefin / diene copolymerization
R1 and R2 charcoal of the general formula (1) using rubber (A)
A long-chain alkyl carbonate (B) with a limited number of primes is blended in a specific ratio, so that wear resistance and friction coefficient
Excellent lifting, can be extended by low hardness is large and obtain a rubber product having excellent cold resistance.

[0039]

DETAILED DESCRIPTION OF THE INVENTION

Example 1 First, the compounding agents shown in Table 1 were kneaded for 5 minutes with a 4.3 liter Banbury mixer (manufactured by Kobe Steel) and dumped out. Next, the kneaded product dumped out was wound around a 14-inch open roll (manufactured by Nippon Roll Co., Ltd.). At this time, the roll surface temperature was 60 ° C. for the front roll and 70 ° C. for the rear roll. On this oven roll, the compounding ingredients shown in Table 2 were added, and after kneading for 2 minutes, a sheet having a thickness of 3 mm was taken out.

Using this compounded rubber, JIS K 630
0 Mooney viscosity was measured at 121 ° C. according to the Unvulcanized Rubber Physical Test Method. The results are shown in Table 3. Further, the compounded rubber was press-vulcanized at 160 ° C. for 10 minutes to obtain a vulcanized rubber sheet having a thickness of 2 mm. Using this sheet, JIS K 6301 was used.
According to the vulcanized rubber physical test method, measurement was carried out in an atmosphere of 25 ° C. Further, a Taber abrasion test was performed in an atmosphere of 25 ° C. based on JIS K 6264. The results are shown in Table 3.

[0041]

[Table 1] * 1 Ethylene / propylene (molar ratio) = 68/32 Mooney viscosity _{ML 1 + 4 (100 ℃)} = 140 iodine value (5-ethylidene-2-norbornene) = 12 * 2 below long-chain alkyl carbonates C ₁₄ H ₂₉ OCOOC ₁₄ H ₂₉ * 3 Asahi # 70 (trademark, manufactured by Asahi Carbon Co., Ltd.)

[0042]

[Table 2]

Example 2 In Example 1, 40 parts by weight of the long-chain alkyl carbonate used in Example 1 as a softening agent and a commercially available softening agent, paraffinic process oil PX-90 (trademark, manufactured by Idemitsu Kosan Co., Ltd.) Example 1 was repeated except that 40 parts by weight were used in combination. The results are shown in Table 4.

Example 3 In Example 1, except that the blending amount of the long-chain alkyl carbonate was changed to 140 parts by weight and 60 parts by weight of FEF carbon black (trademark, manufactured by Asahi Carbon Co., Ltd.) was added as a reinforcing agent. Was performed in the same manner as in Example 1. The results are shown in Table 4.

Example 4 Example 4 was carried out in the same manner as in Example 1 except that the EPT rubber having the following properties was used. The results are shown in Table 5. Ethylene / propylene (molar ratio) = 66/34 Mooney viscosity ML _{1 + 4} (100 ° C.) = 38 Iodine number (5-ethylidene-2-norbornene) = 13

Example 5 Example 5 was repeated except that the following long chain alkyl carbonates were used. The results are shown in Table 5. C ₁₂ H ₂₅ OCOOC ₁₂ H ₂₅

Example 6 The procedure of Example 1 was repeated, except that the following long-chain alkyl carbonates were used. The results are shown in Table 5. ROCOOR R represents a mixture of alkyl groups, the proportions of which are: _{C 12 H 25 / C 13 H} 27 / C 14 H 29 / C 15 H 31 = 40/10/45/5

Comparative Example 1 In Example 1, a commercially available paraffin-based process oil PX was used as the softening agent instead of the long-chain alkyl carbonate.
The same procedure as in Example 1 was performed except that -90 (trademark, manufactured by Idemitsu Kosan Co., Ltd.) was used. The results are shown in Table 3.

Comparative Example 2 In Example 1, a commercially available paraffinic process oil PW was used instead of the long-chain alkyl carbonate as the softening agent.
The same procedure as in Example 1 was performed except that -90 (trademark, manufactured by Idemitsu Kosan Co., Ltd.) was used. The results are shown in Table 3.

Comparative Example 3 In Example 1, 10 parts by weight of a long-chain alkyl carbonate as a softening agent and paraffinic process oil PX were used.
Example 1 was repeated except that 70 parts by weight of -907 was used. The results are shown in Table 4.

Comparative Example 4 In Example 1, 180 parts by weight of a long-chain alkyl carbonate was used as a softening agent, and FEF carbon black 10 was used.
Example 1 was repeated except that 0 part by weight was further added. The results are shown in Table 4.

Comparative Example 5 The procedure of Example 1 was repeated, except that long-chain alkyl carbonate was not added as a softening agent. The results are shown in Table 3.

[0053]

[Table 3] * 1 Worn wheel: H-22, load: 1000 g, rotation speed: 70 rpm

[0054]

[Table 4] * 1 Worn wheel: H-22, load: 1000 g, rotation speed: 70 rpm

[0055]

[Table 5] * 1 Worn wheel: H-22, load: 1000 g, rotation speed: 70 rpm

Examples 7 to 8 The compounding agents shown in Table 6 were kneaded for 5 minutes with a 4.3 liter Banbury mixer (manufactured by Kobe Steel) and dumped out.
Next, the dumped out mixture was wound around a 14-inch open roll (manufactured by Nippon Roll Co., Ltd.). At this time, the roll surface temperature was 60 ° C. for the front roll and 70 ° C. for the rear roll. 1.5 parts by weight of sulfur was added on the open roll, and 1.5 parts by weight of Sancella Cz (trademark, manufactured by Sanshin Chemical Co., Ltd.) as a vulcanization accelerator and Sanseller TS (trademark, manufactured by Sanshin Chemical Co., Ltd.) were added. )) 0.7 parts by weight, the sun cellar TRA
0.7 parts by weight, Sunceller Bz (trademark, Sanshin Chemical Co., Ltd.)
1.0 part by weight was added, and the mixture was kneaded for 2 minutes, and then a sheet having a thickness of 3 mm was taken out.

Using this compounded rubber, JIS K 630
0 unvulcanized rubber physical test method, Vm, t5, T90
Was measured. The results are shown in Table 7. In addition, the above compounded rubber
Press vulcanization at 60 ° C. for 15 minutes to obtain a vulcanized rubber sheet having a thickness of 2 mm, and using this sheet, according to JIS K 6301 vulcanized rubber physical test method, tensile stress at 100% elongation (M100), 200% elongation Tensile stress (M20
0), tensile stress at 300% elongation (M300), tensile strength at break (T _B), elongation at break (E _B), hardness (JI
S-A) was measured (H _S). In addition, the above compounded rubber 16
A CS block was obtained by press vulcanization at 0 ° C. for 20 minutes, and using this block, the compression set was measured according to JIS K 6301 vulcanized rubber physical test method. Also JIS K
Based on 6264, a Taber abrasion test was performed in an atmosphere of 25 ° C. The results are shown in Table 7.

Further, the compounded rubber was press-vulcanized at 160 ° C. for 20 minutes to obtain a cylinder having a diameter of 10 mm and a length of 2 m.
Using this column as a test piece for an OA roll, a friction and wear tester TRI-S10D (trademark, manufactured by Takachiho Machine Co., Ltd.)
Was used to measure the friction coefficient (μ). Measurement conditions are 25 ℃,
The rotation speed was 500 rpm, the load on the test piece was 530 g, and the copy paper was attached to the rotating plate for measurement. The evaluation was performed as follows. First, the initial friction coefficient (value after 50 rotations) is measured, and it is rotated as it is up to 10,000 times, then a new copy break is attached to the rotating body, the friction coefficient after 50 rotations is measured, and 10,000 times after The coefficient of friction was used. The results are shown in Table 7.

Comparative Examples 6 to 9 The same procedure as in Example 7 was carried out except that the compounding ingredients shown in Table 6 were used. The results are shown in Table 7.

[0060]

[Table 6]

Note 6 in Table 6: 40 parts by weight of oil extension (paraffin oil), ethylene / propylene molar ratio = 78/22, Mooney viscosity M
L _{1 + 4} (100 ° C.) = 69, iodine value (5-ethylidene-
2-norbornene) = 12 * 2 Ethylene / 1-butene molar ratio = 90/10, Mooney viscosity ML _{1 + 4} (100 ° C.) = 20, iodine value (5-
_{Ethylidene-2-norbornene) = 20 * 3 C 12 H} 25 OCOOC 15 H 31 * 4 C 8 H 17 OCOOC 8 H 17 * 5 C 22 H 45 OCOOC 22 H 45 * 6 trade, Idemitsu Kosan Co., Ltd. * 7 Trademark, manufactured by Shiraishi Industry Co., Ltd.

[0062]

[Table 7] Note * 1 in Table 7 Wear wheel: H-22, load: 1000 g, rotation speed:
70 rpm

From the results of Table 7, in Examples 7 and 8 in which the long-chain alkyl carbonate represented by the general formula (1) was blended, the friction coefficient and the change rate after 10,000 times with respect to the initial friction coefficient were zero. It is also +7, and it can be seen that it hardly changes or is small. On the other hand, in Comparative Examples 6 and 7 in which PW-380 was blended as the softening agent, the change rate was +24 or +27,
The change in friction coefficient was large. In Comparative Example 6, the polymer itself was resin-like and hard, but the change in the friction coefficient was large because the B component was not mixed. When the carbon number of the alkyl carbonate was less than 10 (Comparative Example 8), the alkyl carbonate bleeded out on the rubber surface, which was not suitable. On the other hand, when the carbon number of the alkyl carbonate was more than 20 (Comparative Example 9), the alkyl carbonate did not form a film, and therefore the effect of improving the wear resistance and the friction coefficient could not be maintained.

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-7-48478 (JP, A) JP-A-5-301998 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08L 1/00-101/16 C08K 3/00-13/08

Claims (2)

(57) [Claims] 1. A long-chain alkyl carbonate 15 to 1 represented by (B) the following general formula (1) per 100 parts by weight of (A) ethylene / α-olefin / diene copolymer rubber.
A crosslinkable rubber composition comprising 60 parts by weight. R ¹ OCOOR ² ... (1) (wherein R ¹ and R ² are the same or different,
A linear or branched alkyl group having 10 to 20 carbon atoms, a cycloalkyl group, or an alkyl group containing a cycloalkyl group, wherein at least one of R ¹ and R ² is a direct alkyl group having 10 to 20 carbon atoms. It is a chain or branched alkyl group. ) 2. The ethylene / α-olefin / diene copolymer rubber (A) has an α-olefin having 3 to 30 carbon atoms,
Ethylene / α-olefin molar ratio is 55/45 to 85
/ 15, Mooney viscosity [ML _{1 + 4} (100 ° C)] is 5-4
00, the iodine value is 3-40, The crosslinkable rubber composition according to claim 1.