JP3274706B2 - Rubber composition for heat-resistant anti-vibration rubber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant and vibration-insulating rubber composition, and more particularly, to a rubber composition for an engine mount insulator, a center bearing insulator, an insulator of a rack-and-pinion type steering device, etc., which requires heat resistance. The present invention relates to a heat-resistant vibration-proof rubber composition that can be suitably used as a vibration-proof rubber material.

[0002]

BACKGROUND OF THE INVENTION In recent years, various anti-vibration rubbers used in automobiles have become particularly severe in heat resistance and anti-vibration characteristics. In other words, in recent years, automobiles have tended to have a higher ambient temperature in the engine room as a result of a reduction in heat radiation space in the engine room and an increase in the output of the engine. It's getting tougher. Examples of the various anti-vibration rubbers include rubbers used for engine mount insulators, center bearing insulators, insulators of rack and pinion type steering devices (hereinafter sometimes referred to as rack mount insulators), and the like. Hereinafter, each of these insulators will be described.

[0003] First, the engine mount insulator is required to satisfy not only the function of supporting most of the load of the engine and the function of supporting the torque reaction force generated by the engine, but also good soundproofing and vibrationproofing characteristics. You. Conventionally, engine mount insulators are mainly composed of natural rubber having a moderate vibration damping performance and excellent fatigue resistance (durability), and in some cases, butadiene rubber, styrene / butadiene rubber, chloroprene rubber. , Butyl rubber, etc. are used alone or, in many cases, blended with natural rubber (hereinafter, referred to as
Natural rubber-based material).

[0004] However, as described above, at present, when the thermal environment in the engine room is deteriorating, in terms of heat resistance,
Natural rubber-based materials are reaching their limits. On the other hand, butadiene rubber and styrene / butadiene rubber alone have a problem that durability is inferior to natural rubber and heat resistance is not sufficient. Also, chloroprene rubber is inadequate for use in vibration-proof rubber because of its low-temperature flexibility. Although butyl rubber is excellent in damping performance, it has a fundamental problem that the dynamic magnification is extremely high, and also has a problem that durability is inferior to natural rubber. Conventional ethylene / propylene rubbers are excellent in heat resistance, but have a drawback that durability is inferior to natural rubber.

[0005] Also, in the center bearing insulator of an automobile, the thermal environment deteriorates as in the case of the engine mount insulator described above, and the heat resistance of the conventional center bearing insulator is no longer satisfactory. This center bearing insulator is located at the center of the propeller shaft of FR vehicles and 4WD vehicles, and is used for a joint between the propeller shaft and the center bearing. Vibration from the propeller shaft is directly transmitted to the chassis via the center bearing. It has the role of preventing and preventing the behavior of the propeller shaft and supporting it. Conventionally, natural rubber-based materials have been used for center bearing insulators because they require high strength and low settling. Since the conventional center bearing insulator is a natural rubber-based material, heat aging is severe in a thermal environment exceeding 100 ° C., and is not practical. As a method for improving the heat resistance of a natural rubber-based material, there is a method called semi-effective vulcanization or effective vulcanization in which the amount of sulfur as a vulcanizing agent is reduced to perform vulcanization. However, such a method improves the heat resistance of the natural rubber-based material, but has the effect of improving the heat resistance at about 10 ° C., and has the drawback that the durability is deteriorated. Did not.

[0006] Chloroprene rubber, ethylene propylene rubber, butyl rubber and the like have been known as raw rubbers having higher heat resistance than natural rubber materials, but these rubbers have the above-mentioned problems. There are disadvantages.

Further, the heat environment of a rack mount insulator of an automobile is deteriorated as in the case of the engine mount insulator and the center bearing insulator described above, and the heat resistance of the conventional rack mount insulator is no longer satisfactory. I have.

The rack mount insulator is used for a fastening portion between the steering wheel and the rack, and prevents vibrations from the tire from being directly transmitted to the steering wheel via the rack, and has a good effect on steering sensitivity. Is responsible for. Therefore, rack mount insulators are required to have adequate vibration damping performance and excellent fatigue resistance (durability). Conventionally, natural rubber materials have been used as materials for rack mount insulators that meet these requirements. Have been.

However, as described above, natural rubber-based materials have reached their limits in terms of heat resistance due to the deterioration of the thermal environment in the engine room. On the other hand, EP with excellent heat resistance
DM has a drawback that durability is inferior to natural rubber-based materials.

Therefore, a rubber composition for a heat-resistant and vibration-proof rubber having the same level of vibration-proof properties and durability as a natural rubber-based vibration-proof rubber and having a heat resistance superior to that of a natural rubber-based material has been used. Was desired.

[0011]

SUMMARY OF THE INVENTION The object of the present invention is to solve the problems associated with the prior art as described above, and has the same vibration-damping properties and durability as natural rubber-based vibration-isolating rubbers.
An object of the present invention is to provide a rubber composition for heat-resistant and vibration-proof rubber, which can provide a vibration-proof rubber having better heat resistance than natural rubber-based materials.

[0012]

SUMMARY OF THE INVENTION The rubber composition for heat-resistant and vibration-proof rubber according to the present invention comprises [I] ethylene, an α-olefin having 3 to 20 carbon atoms and a non-conjugated diene, and ethylene and an α-olefin. Is 60/40 to 73/27, and G
Molecular weight distribution (Mw / Mn) determined by PC method measurement
Q value is less than 4, intrinsic viscosity [η] measured in decalin at 135 ° C. is 2.7 to 5.0 dl / g, iodine value is 10 to 40, and non-conjugated diene is 5-ethylidene.
-Norbornene ethylene / α-olefin / non-conjugated diene copolymer rubber (A): 99 to 60% by weight, and ethylene and α-olefin having 3 to 20 carbon atoms, and ethylene and A liquid ethylene / α-olefin copolymer having a molar ratio to an α-olefin of 50/50 to 78/22 and an intrinsic viscosity [η] of 0.2 to 0.4 dl / g measured in decalin at 135 ° C. Coalescing (B): 1
Ethylene-alpha-olefin-non-conjugated diene copolymer rubber composition comprising 40% by weight a rubber composition mainly, the ethylene-alpha-olefin-nonconjugated diene
[II] 0.1 to 10 parts by weight of sulfur and [III] 40 to 120 parts by weight of carbon black with respect to 100 parts by weight of the copolymer rubber composition [I].
And a loss tangent (tan δ) determined in a dynamic viscoelasticity test after vulcanization is 0.15 to 0.35.

[0013]

[0014] The rubber composition for heat-resistant and vibration-proof rubber of the present invention comprises a rubber composition for an automobile engine mount insulator,
It is preferably used as a rubber composition for an automobile center bearing insulator or an insulator for an automobile rack and pinion type steering device.

[0015]

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the rubber composition for heat and vibration proof rubber according to the present invention will be specifically described. The rubber composition for a heat-resistant and vibration-proof rubber according to the present invention comprises:
A unvulcanized rubber composition is composed of α- olefin-non-conjugated diene copolymer rubber composition, ethylene
・ Α-olefin / non-conjugated diene copolymer rubber composition
In addition to [I], [II] sulfur and [III] carb
And a loss tangent (tan δ) determined by a dynamic viscoelasticity test after vulcanization is in a specific range . The rubber composition of this can be used as an insulator (vulcanized rubber) with vulcanization molding. Examples of the insulator include the engine mount insulator, the center bearing insulator, and the rack mount insulator as described above.

[I] Ethylene / α-olefin / non-conjugate
Diene copolymer rubber composition The ethylene / α-olefin / non-conjugated diene copolymer rubber composition used in the present invention comprises a specific ethylene / α-olefin / non-conjugated diene copolymer rubber (A) And a liquid ethylene / α-olefin copolymer (B).

Ethylene / α-olefin / non-conjugated diene
Copolymer rubber (A) The above-mentioned ethylene / α-olefin / non-conjugated diene copolymer rubber (A) is a high-molecular-weight rubber composed of ethylene, an α-olefin having 3 to 20 carbon atoms and a non-conjugated diene. is there.

This ethylene / α-olefin / non-conjugated diene copolymer rubber (A) has a molar ratio of ethylene / α-olefin [ethylene / α-olefin] of 60/40.
73/27, preferably 65/35 to 70/30. When the above molar ratio is less than 60/40, the vulcanized rubber of the obtained rubber composition tends to have reduced strength. On the other hand, when the molar ratio exceeds 73/27, the vulcanized rubber of the obtained rubber composition tends to have low-temperature flexibility.

Examples of the α-olefin having 3 to 20 carbon atoms include propylene, butene-1, hexene-1, pentene-1,4-methylpentene-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, octadecene-1
1, nonadecene-1, eicosene-1 and the like. These α-olefins are used alone or in combination. Of these, propylene is particularly preferred.

As the non-conjugated diene, specifically, 5-ethylidene-2-norbornene is used. The ethylene / α-olefin / non-conjugated diene copolymer rubber (A) has an iodine value of 10 to 40, preferably 15 to 25, which is an index of the non-conjugated diene content. When the iodine value is less than 10, the obtained rubber composition tends to have a low vulcanization rate. On the other hand, when the iodine value exceeds 40, the vulcanized rubber of the obtained rubber composition tends to have reduced heat resistance.

The ethylene / α-olefin / non-conjugated diene copolymer rubber has a molecular weight distribution (Mw / Mn) Q value determined by GPC measurement of less than 4, preferably 3 or less. Use of a high molecular weight ethylene / α-olefin / non-conjugated diene copolymer rubber (A) having such a molecular weight distribution to provide a vulcanized rubber excellent in mechanical strength characteristics and dynamic fatigue resistance. It becomes possible to obtain the rubber composition which can be made.

The ethylene / α-olefin / non-conjugated diene copolymer rubber (A) has an intrinsic viscosity [η] of 2.7 to 5.0 dl / g measured in decalin at 135 ° C.,
Preferably it is 3.5-4.5 dl / g. If the intrinsic viscosity [η] is less than 2.7 dl / g, the durability tends to decrease. On the other hand, the intrinsic viscosity [η] is 5.0 dl /
If it exceeds g, the productivity of polymer synthesis tends to decrease. When an ethylene / α-olefin / non-conjugated diene copolymer rubber having an intrinsic viscosity [η] in the above range is used, a rubber composition having excellent dynamic fatigue resistance can be obtained.

The ethylene / α-olefin /
Non-conjugated diene copolymer rubbers are described, for example, in JP-B-59-1.
It can be produced by the method described in JP-A-4497. That is, using hydrogen as a molecular weight regulator in the presence of a Ziegler catalyst, ethylene and
By copolymerizing an α-olefin of ２０20 and a diene, an ethylene / α-olefin / non-conjugated diene copolymer rubber can be obtained.

Liquid ethylene / α-olefin copolymer (B) The liquid ethylene / α-olefin copolymer (B) is
It is a low molecular weight copolymer composed of ethylene and an α-olefin having 3 to 20 carbon atoms, and does not contain a diene component.

The above liquid ethylene / α-olefin copolymer is a random copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms. The above number of carbon atoms 3 to
Specific examples of the α-olefin of 20 include propylene, butene-1, pentene-1,4-methylpentene-
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, octadecene-1, nonadecene-1, eicosene-1, and the like. These α-olefins are used alone or in combination. Of these, propylene is particularly preferred.

In the present invention, the high molecular weight ethylene / α-olefin / non-conjugated diene copolymer rubber (A)
Has the effect of improving heat resistance, mechanical strength characteristics, dynamic fatigue resistance, etc., while the low molecular weight liquid ethylene / α-olefin copolymer (B) has heat aging resistance, workability (flow The quality was designed so that the effects of improving the properties) could be played.

However, an ethylene / α-olefin / non-conjugated diene copolymer rubber composition consisting of a high molecular weight component and a low molecular weight component, which is simply bimodal, ie, has a molecular weight distribution having two modes, has a high molecular weight. Since the ratio of the improvement effect of the physical properties such as heat resistance, mechanical strength characteristics, and dynamic fatigue resistance by the component and the ratio of the improvement effect of the workability (flowability) by the low molecular weight component are in a tug-of-war relationship, for example, Even if the low molecular weight component is increased and the processability is excellent, it is not possible to provide a vulcanized rubber in which physical properties such as fatigue resistance are dramatically improved.

The inventors of the present invention have conducted further studies on this low molecular weight component and found that a vulcanized rubber was obtained from an ethylene / α-olefin / non-conjugated diene copolymer rubber composition exhibiting a bimodal molecular weight distribution. When it was obtained, it was found that it was necessary that the low molecular weight component constituting the vulcanized rubber was not crosslinked as a polymer. That is, in the present invention, a liquid ethylene / α-olefin copolymer containing no diene is used as the low molecular weight component.

The liquid ethylene / α-olefin copolymer (B) used in the present invention has a molar ratio of ethylene / α-olefin of 50/50 to 78/22 mol%, preferably 50/50 to 70/30. , More preferably 50/50
６０60/40. The liquid ethylene / α-olefin copolymer having the above molar ratio in the above range has good thermal stability, and therefore has a high molecular weight ethylene / α-olefin / non-conjugated diene copolymer as described above. The weight does not decrease during the kneading operation with the rubber (A), and there is no carbonization during molding to contaminate the molded product.

The liquid ethylene / α-olefin copolymer (B) has an intrinsic viscosity [η] measured at 135 ° C. in decalin of 0.2 to 0.4 dl / g, preferably 0.24 dl / g.
０．４0.4 dl / g. The intrinsic viscosity [η] is 0.2
If it is less than dl / g, the resulting ethylene / α-olefin / non-conjugated diene copolymer rubber composition tends to have low processability (fluidity). On the other hand, when the intrinsic viscosity [η] exceeds 0.4 dl / g, the vulcanized rubber of the obtained ethylene / α-olefin / non-conjugated diene copolymer rubber composition has a larger dynamic magnification as tan δ increases. , There is a tendency that the ability to suppress high frequency range vibrations is reduced.

The above liquid ethylene / α-olefin copolymer can be produced, for example, by the method described in Japanese Patent Publication No. 2-1163. That is, in the presence of a Ziegler catalyst, a liquid ethylene / α-olefin copolymer is obtained by randomly copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms using hydrogen as a molecular weight regulator. Can be.

Ethylene / α-olefin / non-conjugated diene
Production of Copolymer Rubber Composition The ethylene / α-olefin / non-conjugated diene copolymer rubber composition [I] used in the present invention has a high molecular weight ethylene / α-olefin / non-conjugated diene copolymer rubber ( A) is 99 to 6% based on 100% by weight of the total amount of the ethylene / α-olefin / non-conjugated diene copolymer rubber (A) and the liquid ethylene / α-olefin copolymer (B).
0% by weight, low molecular weight liquid ethylene α
The olefin copolymer (B) is present in a proportion of 1 to 40% by weight, based on 100% by weight of the total of the above (A) and (B).

The ethylene / α-olefin /
The non-conjugated diene copolymer rubber composition [I] has a Mooney viscosity ML _{1 + 4} (100 ° C.) of usually 20 to 150, preferably 30 to 135, and a molecular weight of 3,000 to 1
Iodine value (IV ₁ ) and molecular weight of 5,000 ethylene / α-olefin / non-conjugated diene copolymer rubber composition
The iodine value (IV) of the ethylene / α-olefin / non-conjugated diene copolymer rubber composition of 000 to 120,000
₂₎ and the ratio (IV ₁ / IV ₂₎ is usually 0.1 or less, preferably 0. An ethylene / α-olefin / non-conjugated diene copolymer rubber composition [I] having a Mooney viscosity ML _{1 + 4} (100 ° C.) and the above iodine value ratio (IV ₁ / IV ₂ ) within the above range. ] Is excellent in kneading properties using a Banbury mixer or the like.

The ethylene / α-olefin / non-conjugated diene copolymer rubber composition [I] used in the present invention is a solution or suspension of the ethylene / α-olefin / non-conjugated diene copolymer rubber (A). And a liquid ethylene / α-olefin solution or suspension, and then a solid is recovered. First, either an ethylene / α-olefin / non-conjugated diene copolymer rubber (A) or a liquid ethylene / α-olefin copolymer (B) is obtained by polymerization, and further, in the presence of the polymer, The ethylene / α-olefin / non-conjugated diene copolymer rubber composition [I] of the present invention can also be obtained by a so-called multistage polymerization method in which other components are obtained by polymerization.

[II] Sulfur The above-mentioned sulfur is used as a vulcanizing agent. Sulfur is used in a proportion of 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the ethylene / α-olefin / non-conjugated diene copolymer rubber composition [I]. Can be In the present invention, sulfur is present in the unvulcanized rubber composition, but may be used when vulcanizing the above-mentioned ethylene / α-olefin / non-conjugated diene copolymer rubber composition.

[III] Carbon Black The carbon black is not particularly limited as long as it is carbon black for rubber.
Furnace carbon black such as F, FEF and GPF is preferred.

In the rubber composition for heat and vibration proof rubber according to the present invention, carbon black is the above-mentioned ethylene / α-olefin / non-conjugated diene copolymer rubber composition [I] 10
It is used in the range of 40 to 120 parts by weight with respect to 0 parts by weight. If the amount of the carbon black is less than 40 parts by weight, the vulcanized rubber of the obtained rubber composition tends to have reduced hardness and strength. On the other hand, if the compounding amount of carbon black exceeds 120 parts by weight, the resulting rubber composition tends to have low processability and poor carbon black dispersion. In the present invention, carbon black is
Although present in the unvulcanized rubber composition, it may be used when vulcanizing the above-mentioned ethylene / α-olefin / non-conjugated diene copolymer rubber composition.

Other Compounding Agents In the rubber composition for heat-resistant and vibration-proof rubber of the present invention, the above-mentioned ethylene / α-olefin / non-conjugated diene copolymer rubber composition [I], sulfur [II] and carbon black [II]
In addition to I), a compounding agent such as a vulcanization accelerator, a vulcanization aid, or a softening agent, which has been widely used conventionally in the production of a vulcanized rubber molded article composed of ethylene / propylene rubber or the like, is used in the present invention. It can be used within a range that does not impair the purpose.

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,
Thiazole compounds such as 2- (2,4-dinitrophenyl) mercaptobenzothiazole, 2- (2,6-diethyl-4-morpholinothio) benzothiazole, dibenzothiazyl-disulfide; diphenylguanidine, triphenylguanidine, Guanidine compounds such as orthotolyl guanidine, ortho tolyl by guanide, diphenyl guanidine phthalate; aldehyde-amine or aldehyde such as acetaldehyde-aniline reactant, butyraldehyde-aniline condensate, hexamethylenetetramine, acetaldehyde-ammonia reactant Ammonia compounds; imidazoline compounds such as 2-mercaptoimidazoline; thioliuyl such as thiocarbanilide, diethylthiourea, dibutylthiourea, trimethylthiourea, diorthotolylthiourea System compound; tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethyl thiuram disulfide, tetrabutyl thiuram disulfide, thiuram-based compounds such as pentamethylene thiuram tetrasulfide; zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate,
Zinc di-n-butyldithiocarbamate, zinc ethylphenyldithiocarbamate, zinc butylphenyldithiocarbamate, sodium dimethyldithiocarbamate,
Dithioate compounds such as selenium dimethyldithiocarbamate and tellurium diethyldithiocarbamate; xanthate compounds such as zinc dibutylxanthate; and compounds such as zinc white are used.

These vulcanization accelerators include the above-mentioned ethylene / α
-Olefin / non-conjugated diene copolymer rubber composition [I]
It is 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.

As the softening agent, a softening agent usually used for rubber is used, and specific examples thereof include petroleum softening agents such as process oil, lubricating oil, paraffin, liquid paraffin, petroleum asphalt, petrolatum; Coal tar softeners such as tar and coal tar pitch; fatty oil softeners such as castor oil, linseed oil, rapeseed oil and coconut oil;
Tall oil; sub; 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 resins, atactic polypropylene, cumarone indene resins And the like are used. Among them, a petroleum softener is preferably used, and particularly, a process oil is preferably used.

The rubber composition for heat-resistant and vibration-proof rubber (unvulcanized compounded rubber) according to the present invention is prepared, for example, by the following method. That is, using a mixer such as a Banbury mixer, the ethylene / α-olefin / non-conjugated diene copolymer rubber composition and the softener were mixed in an amount of 80 to 170.
Kneading at a temperature of 3 ° C. for 3 to 10 minutes, and then using a roll such as an open roll, sulfur and carbon black as a vulcanizing agent, and if necessary, a vulcanization accelerator or a vulcanization aid are additionally mixed. 5-3 at a roll temperature of 40-80 ° C
After kneading for 0 minutes, the kneaded material is extruded to prepare a ribbon or sheet compound rubber.

The rubber composition for heat and vibration proof rubber of the present invention has a loss tangent (tan) determined by a dynamic viscoelasticity test after vulcanization.
δ) is 0.15 to 0.35. That is, the rubber composition for an automobile engine mount insulator, the rubber composition for an automobile center bearing insulator, and the rubber composition for an insulator of an automobile rack and pinion type steering device of the present invention are determined by a dynamic viscoelasticity test after vulcanization. The composition has a loss tangent (tan δ) of 0.15 to 0.35. When this tan δ is less than 0.15,
Since the amount of the sub-material affecting the dynamic characteristics (tan δ) cannot be set to an appropriate amount, the reinforcing effect of the sub-material is reduced, and the strength characteristics required for the vibration-proof rubber may not be satisfied. There is.

Production of Vulcanized Rubber In order to obtain a vulcanized rubber from the rubber composition for heat and vibration proof rubber according to the present invention, the above-mentioned unvulcanized compounded rubber is molded into an intended shape and then vulcanized. .

That is, the above-mentioned unvulcanized compounded rubber is molded into an intended shape by an extruder, a calender roll, or a press, and simultaneously with molding or by introducing the molded product into a vulcanization tank at 130 to 270 ° C. At a temperature of 1 to 30 minutes to obtain a vulcanized rubber. When performing such vulcanization,
A mold may or may not be used.

[0046]

The rubber composition according to the present invention comprises a specific ethylene / α-olefin / non-conjugated diene copolymer rubber composition as a main component and is determined by a dynamic viscoelasticity test after vulcanization. Since the loss tangent (tan δ) is in a specific range,
It has anti-vibration properties and durability comparable to that of natural rubber-based rubber, heat resistance superior to natural rubber-based materials, and excellent low-temperature flexibility. Can be provided.

Hereinafter, the present invention will be described with reference to Examples.
The present invention is not limited to these examples. The ethylene / α-olefin / non-conjugated diene copolymer rubber in Examples and Comparative Examples, a rubber composition comprising this copolymer rubber and a liquid ethylene / α-olefin copolymer, and an insulator (vulcanized rubber) The test method for ()) is as follows.

[1] Molecular Weight Distribution (Mw / Mn) Q Value The molecular weight distribution (Mw / Mn) Q value is measured as follows according to Takeuchi's “Gel Permeation Chromatography” published by Maruzen Co., Ltd. Was. (1) Molecular weight M and its GPC using standard polystyrene of known molecular weight (monodisperse polystyrene manufactured by Tosoh Corporation)
(Gel Permeation Chromatog
and the molecular weight M and elution volume E
A correlation curve with V (Elution Volume) is prepared. At this time, the polystyrene concentration is 0.02% by weight. (2) The GPC pattern of the sample is obtained by the GPC measurement method, and the molecular weight M is determined by the above (1). The sample preparation conditions and GPC measurement conditions at that time are as follows.

Sample preparation conditions (a) A sample is taken together with an o-dichlorobenzene solvent into an Erlenmeyer flask so that its concentration becomes 0.04% by weight. (B) The anti-aging agent 2,6-
0.1% by weight of di-tert-butyl-p-cresol is added to the polymer solution. (C) Heat the Erlenmeyer flask to 140 ° C. and stir for about 30 minutes to dissolve the sample. (D) Thereafter, while maintaining the Erlenmeyer flask at 135 to 140 ° C., filtration is performed with a 1 μm diameter pore filter. (E) The filtrate is subjected to GPC analysis.

GPC measurement conditions (a) Apparatus: 200 type manufactured by Waters (b) Column: S-type (Mix type) manufactured by Tosoh Corporation (c) Sample amount: 2 ml (d) Temperature: 135 ° C (e) Flow rate: 1 ml / mm (H) Total theoretical number of columns: 2 × 10 ⁴ to 4 × 10 ⁴ (measured value with acetone) [2] Processability The processability of the rubber composition is evaluated as follows: A three-point evaluation of x was performed.

：: Excellent workability. Δ: Workability is good. ×: Poor workability.

[3] Hardness test The hardness test was performed according to JIS K 6301 (1989), and the spring hardness (JIS A hardness) was measured.

[4] Gehman low-temperature torsion test The Gehman low-temperature torsion test was conducted according to JIS K6301 (19).
1989), T ₂ [unit: ° C.], T
₁₀ [Unit: ° C.] was determined.

[5] Product Durability Test of Engine Mount Insulator The product durability test was conducted by applying an initial load of 90 kg in the P direction to the insulator 2 of the automobile engine mount 1 shown in FIGS. 1 to 3 which had been thermally aged under the following conditions. After loading, insulator 2 under the condition of ± 180 kg constant load
Was performed until the sample broke, and the number of breaks was measured. The ambient temperature for this test was room temperature. Other test conditions are as follows.

Heat aging conditions: 120 ° C., 72 hours, excitation frequency: 5 Hz, 2 Hz The number of breaks was 6 in number of samplings, and the average of four breaks excluding the minimum and maximum of these breaks Value.

[6] Product Endurance Test of Center Bearing Insulator The product endurance test was carried out in FIG.
± 10mm in the Q direction with the propeller shaft 3
While moving, it was performed at 120 ° C. and 140 ° C. at an excitation frequency of 7 Hz until the insulator 5 was broken, and the number of breaks was measured. The ambient temperature for this test was
The temperature was 100 ° C., and the number of breaks was the average value of the four numbers of breaks excluding the minimum and maximum values of the number of samples at the sampling number of 6.

[7] Product Settling Test of Center Bearing Insulator In the product settling test, the amount of settling of the insulator 5 heat-aged at 100 ° C. for 300 hours under a load of 7 kg in the P direction and 100 ° C. in FIG. The amount of settling of the insulator 5 which had been heat-aged for 1,000 hours was measured. The ambient temperature in this test is 100 ° C.

[8] Product Durability Test of Rack Mount Insulator The product durability test is performed by attaching jigs 7 and 8 to the rack mount insulator 6 shown in FIGS. 5 and 6 as shown in FIG. ± 600 in P direction under atmosphere
After applying a constant load of kg or ± 1,005 kg and vibrating 100,000 times at a vibration frequency of 3 Hz, the static spring constant change rate was measured.

[9] Dynamic Viscoelasticity Test The dynamic viscoelasticity test was conducted using a rheometric viscoelasticity tester (model RDS-2) at a measurement temperature of 25 ° C., a frequency of 10 Hz and a strain rate of 1%. Dynamic shear modulus (kg / cm ² ) and dynamic loss modulus (kg / cm ² )
And the loss tangent tan δ (index of vibration damping property) was determined by the following equation.

G _s = G ′ + ιG ″ (G _s : static shear modulus, real number G ′: dynamic shear modulus,
Imaginary number G ″: dynamic loss modulus) tan δ = G ″ / G ′ [Examples and Comparative Examples of Rubber Composition for Engine Mount Insulator]

[0061]

Comparative Example 1 70 parts by weight of natural rubber (NR) [RSS No. 1], 30 parts by weight of styrene-butadiene rubber (SBR) [Nipol 1502, manufactured by Nippon Zeon Co., Ltd.], and 1.5 parts of sulfur Parts by weight and carbon black [N
550] 70 parts by weight, zinc oxide 5 parts by weight, stearic acid 1 part by weight, aroma-based process oil (softening agent) 2
5 parts by weight, 5 parts by weight of an antioxidant, 1.5 parts by weight of a vulcanization accelerator (1), and 0.3 part by weight of a vulcanization accelerator (3) were added to a 4.3 liter Banbury. The mixture was kneaded with a mixer [Kobe Steel Ltd.].

From the kneaded material thus obtained, test pieces for the above various tests were prepared and tested. Table 1 shows the results.

[0063]

Comparative Examples 2 and 3 100 parts by weight of EPDM, 0.5 parts by weight of sulfur and carbon black [N55]
0] 70 parts by weight, zinc oxide 5 parts by weight, stearic acid 1 part by weight, paraffin-based process oil (softening agent) 5
0 parts by weight, vulcanization accelerator (1) 3.0 parts by weight, vulcanization accelerator (2) 1.5 parts by weight, and vulcanization accelerator (3) 0.75
The mixture was kneaded with a 4.3 liter Banbury mixer [manufactured by Kobe Steel Ltd.].

From the kneaded material thus obtained, test pieces for the above various tests were prepared and tested. Table 1 shows the results.

[0065]

Comparative Example 4 and Examples 1 to 3 EPDM shown in Table 1
100 parts by weight of composition, 0.5 parts by weight of sulfur, 70 parts by weight of carbon black [N550], 5 parts by weight of zinc oxide, 1 part by weight of stearic acid, and 50 parts by weight of paraffin-based process oil (softening agent) And vulcanization accelerator (1) 3.
0 parts by weight, 1.5 parts by weight of the vulcanization accelerator (2) and 0.75 parts by weight of the vulcanization accelerator (3) were added to a 4.3 liter Banbury mixer [manufactured by Kobe Steel Ltd.] ].

From the kneaded material thus obtained, test pieces for the above various tests were prepared and tested. Table 1 shows the results.

[0067]

[Table 1]

The following can be understood from Table 1. Comparative Example 1 is an example of an NR / SBR material currently used, and this material has particularly poor fatigue resistance after thermal aging because of poor heat resistance.

In Comparative Example 2, EP having a low intrinsic viscosity [η] was used.
Since DM is used, the fatigue resistance is inferior. In Comparative Example 3, the processability was so poor that it could not be commercialized, and could not be evaluated.

In Comparative Example 4, although the processability was good due to the presence of the low molecular weight component (liquid ethylene / propylene copolymer), the blend ratio between EPDM and liquid ethylene / propylene copolymer was 1: 1. On the other hand, when the proportion of the low molecular weight component is large, tan δ becomes too high, so that the vibration damping characteristics and fatigue resistance of the engine mount deteriorate.

According to Examples 1 to 3, the rubber composition of the present invention has excellent workability and fatigue resistance, and in particular, the fatigue resistance after heat treatment is much better than that of Comparative Example 1. is there. [Examples and Comparative Examples of Rubber Composition for Center Bearing Insulator]

[0072]

Comparative Example 5 70 parts by weight of natural rubber (NR) [RSS 1], 30 parts by weight of styrene-butadiene rubber (SBR) [Nipol 1502, trade name, manufactured by Nippon Zeon Co., Ltd.], and 1.5 parts of sulfur Parts by weight and carbon black [N
550] 70 parts by weight, zinc oxide 5 parts by weight, stearic acid 1 part by weight, aroma-based process oil 10 parts by weight, antioxidants 5 parts by weight, vulcanization accelerator (1) 1.5
4.3 parts by weight of 0.3 parts by weight of the vulcanization accelerator (3)
1 liter capacity Banbury mixer [Kobe Steel, Ltd.]
Made).

Test pieces for the various tests described above were prepared from the kneaded materials thus obtained and tested. Table 2 shows the results.

[0074]

Comparative Examples 6 and 7 100 parts by weight of EPDM, 0.5 parts by weight of sulfur and carbon black [N55]
0] 70 parts by weight, zinc oxide 5 parts by weight, stearic acid 1 part by weight, paraffinic process oil 40 parts by weight, vulcanization accelerator (1) 3.0 parts by weight, and vulcanization accelerator (2 ) 1.5 parts by weight and 0.75 parts by weight of the vulcanization accelerator (3) were kneaded with a 4.3 liter capacity Banbury mixer [manufactured by Kobe Steel Ltd.].

From the kneaded material thus obtained, test pieces for the above-mentioned various tests were prepared, and the above-mentioned various tests were performed.
Table 2 shows the results.

[0076]

Comparative Example 8 and Examples 4 to 6 EPDM shown in Table 2
100 parts by weight of the composition, 0.5 parts by weight of sulfur, 70 parts by weight of carbon black [N550], 5 parts by weight of zinc oxide, 1 part by weight of stearic acid, 40 parts by weight of paraffin-based process oil, and vulcanization 3.0 parts by weight of the accelerator (1), 1.5 parts by weight of the vulcanization accelerator (2), and 0.75 parts by weight of the vulcanization accelerator (3) were mixed in a 4.3 liter Banbury mixer [ Kobe Steel Ltd.].

Test pieces for the various tests described above were prepared from the kneaded material thus obtained, and the various tests were performed.
Table 2 shows the results.

[0078]

[Table 2]

The following can be understood from Table 2. Comparative Example 5 is an example of a currently used NR / SBR material, and this material has particularly poor fatigue resistance after thermal aging due to poor heat resistance.

In Comparative Example 6, EP having a low intrinsic viscosity [η] was used.
Since DM is used, the fatigue resistance is inferior. In Comparative Example 7, the processability was so poor that it could not be commercialized, and could not be evaluated.

In Comparative Example 8, the processability was good due to the presence of the low molecular weight component (liquid ethylene / propylene copolymer), but the blend ratio of EPDM and liquid ethylene / propylene copolymer was 1: 1. On the other hand, when the proportion of the low molecular weight component is large, tan δ becomes too high, and the vibration-proofing properties and fatigue resistance of the center bearing deteriorate.

According to Examples 4 to 6, the rubber compositions of the present invention have excellent processability and the amount of set after the heat set test is much smaller than that of Comparative Example 5. [Examples and Comparative Examples of Rubber Composition for Rack Mount Insulator]

[0083]

Comparative Example 9 70 parts by weight of natural rubber (NR) [RSS No. 1], 30 parts by weight of styrene-butadiene rubber (SBR) [Nipol 1502, manufactured by Nippon Zeon Co., Ltd.], and 1.5 parts of sulfur Parts by weight and carbon black [N
550] 60 parts by weight, zinc oxide 5 parts by weight, stearic acid 1 part by weight, aroma-based process oil 25 parts by weight, vulcanization accelerator (1) 1.5 parts by weight, vulcanization accelerator (3 ) 0.3 parts by weight and 5 parts by weight of antioxidants
The mixture was kneaded with a 4.3 liter Banbury mixer [manufactured by Kobe Steel Ltd.].

From the kneaded material thus obtained, test specimens for the above vulcanized rubber hardness test, Gehman low temperature torsion test and product durability test were prepared and tested. Table 3 shows the results.

[0085]

Comparative Examples 10 to 13 100 parts by weight of EPDM, 0.5 parts by weight of sulfur and carbon black [N5
50] The amount shown in Table 3, 5 parts by weight of zinc oxide, 1 part by weight of stearic acid, the amount shown in Table 3 of paraffinic process oil, 3.0 parts by weight of vulcanization accelerator (1), 0.75 parts by weight of the vulcanization accelerator (3) and 1.5 parts by weight of the vulcanization accelerator (2)
The mixture was kneaded with a 4.3 liter Banbury mixer [manufactured by Kobe Steel Ltd.].

From the kneaded product thus obtained, test specimens for the above vulcanized rubber hardness test, Gehman low-temperature torsion test and product durability test were prepared and tested. Table 3 shows the results.

In Comparative Example 12, the EPDM (A) of the present invention was used as the raw rubber, and the compounding amount of carbon black was 20 parts by weight. However, the kneading operation became impossible, and the subsequent experiments could not be performed. .

[0088]

Examples 7 and 8 100 parts by weight of the EPDM composition shown in Table 3, 0.5 part by weight of sulfur, and carbon black [N
550] The amounts shown in Table 3, 5 parts by weight of zinc oxide, 1 part by weight of stearic acid, and paraffinic process oil No. 3
The amounts shown in the table, 3.0 parts by weight of the vulcanization accelerator (1), 0.75 parts by weight of the vulcanization accelerator (3), and 1.
5 parts by weight were kneaded using a 4.3 liter capacity Banbury mixer [manufactured by Kobe Steel Ltd.].

From the kneaded material thus obtained, test specimens for the above vulcanized rubber hardness test, Gehman low temperature torsion test and product durability test were prepared and tested. Table 3 shows the results.

[0090]

Comparative Example 14 Natural Rubber (NR) [RSS No. 1] 50
Parts by weight and styrene-butadiene rubber (SBR) [manufactured by Zeon Corporation, trade name: Nipol 1502] 50
Parts by weight, 1.5 parts by weight of sulfur, 90 parts by weight of carbon black [N550], 5 parts by weight of zinc oxide, 1 part by weight of stearic acid, 20 parts by weight of aroma-based process oil, and a vulcanization accelerator ( 1) 1.5 parts by weight, 0.2 parts by weight of a vulcanization accelerator (3), and 5 parts by weight of an antioxidant,
The mixture was kneaded with a 4.3 liter Banbury mixer [manufactured by Kobe Steel Ltd.].

From the kneaded material thus obtained, test specimens for the above vulcanized rubber hardness test, Gehman low temperature torsion test and product durability test were prepared and tested. Table 3 shows the results.

[0092]

Comparative Example 15 100 parts by weight of EPDM shown in Table 3
0.5 parts by weight of sulfur and carbon black [N550]
95 parts by weight, zinc oxide 5 parts by weight, stearic acid 1 part by weight, paraffin-based process oil 50 parts by weight, vulcanization accelerator (1) 3.0 parts by weight, and vulcanization accelerator (3) 0 .
75 parts by weight and 1.5 parts by weight of the vulcanization accelerator (2)
The mixture was kneaded with a 4.3 liter Banbury mixer [manufactured by Kobe Steel Ltd.].

From the kneaded product thus obtained, test specimens for the above vulcanized rubber hardness test, Gehman low temperature torsion test and product durability test were prepared and tested. Table 3 shows the results.

Comparative Example 15 is an example in which EPDM containing no liquid ethylene / propylene copolymer was used as the raw rubber. In this case, the kneading operation became impossible, and the subsequent experiments could not be performed.

[0095]

Comparative Example 16 and Examples 9 to 10 EP shown in Table 3
100 parts by weight of the DM composition, 0.5 parts by weight of sulfur, carbon black [N550], the amount shown in Table 3, 5 parts by weight of zinc oxide, 1 part by weight of stearic acid, and a vulcanization accelerator (1) 3.0 parts by weight, 0.75 parts by weight of the vulcanization accelerator (3) and 1.5 parts by weight of the vulcanization accelerator (2) were added to a 4.3 liter Banbury mixer [Kobe Steel, Ltd. ))
And kneaded.

From the kneaded material thus obtained, test specimens for the above vulcanized rubber hardness test, Gehman low-temperature torsion test and product durability test were prepared and tested. Table 3 shows the results.

[0097]

[Table 3]

[0098]

[Table 4]

The following can be understood from Table 3. In Comparative Examples 9, 11, and 13, the rate of change of the static spring constant is large, and the product durability is insufficient.

In Comparative Example 10, the low-temperature flexibility was insufficient. In Comparative Example 12, as described above, the kneading operation is impossible and cannot be put to practical use.

In contrast to the comparative example, Examples 7 and 8 exhibited satisfactory performance in workability, low-temperature flexibility and product durability. In Comparative Example 14, the change rate of the static spring constant was large, and the product durability was insufficient.

In Comparative Example 15, as described above, the kneading operation is impossible and cannot be put to practical use. In Comparative Example 16, although the workability was excellent, the change rate of the static spring constant was large, and the product durability was insufficient.

In Example 9, the workability was excellent, and the product durability was significantly improved as compared with the prior art. In Example 10, workability and product durability were improved.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a state in which an automobile engine mount insulator manufactured in an example and a comparative example is incorporated in an engine mount.

FIG. 2 is a plan view of the engine mount of FIG. 1;

FIG. 3 is a view showing an A- of an engine mount in FIG. 2;
It is A sectional drawing.

FIG. 4 is a schematic cross-sectional view showing a state where the automobile center bearing insulators manufactured in Examples and Comparative Examples are used for fastening a propeller shaft and a center bearing.

FIG. 5 is a schematic perspective view showing an insulator of an automobile rack and pinion type steering device manufactured in an example and a comparative example.

FIG. 6 is a front view of the insulator of FIG. 5;

FIG. 7 is a schematic sectional view showing a state of a durability test of the insulator shown in FIGS. 5 and 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Engine mount 2 ... Engine mount insulator 3 ... Propeller shaft 4 ... Center bearing 5 ... Center bearing insulator 6 ... Rack mount insulator 7, 8 ... Jig

────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI C08K 3:06) C08K 3:06) (72) Inventor Norihiro Harada 330, Naganumacho, Inage-ku, Chiba-shi, Chiba Oni Onugawa Rubber Industries Co., Ltd. (72) Inventor Hiroshi Toriyabe 330, Naganuma-cho, Inage-ku, Chiba-shi, Chiba Kinu-Kugawa Rubber Industries Co., Ltd. (56) References JP-A-5-86236 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08K 3/00-13/08 C08L 23/00-23/36

Claims (4)

(57) [Claims] [1] [I] ethylene and α having 3 to 20 carbon atoms
-Consisting of an olefin and a non-conjugated diene, and having a molar ratio of ethylene / α-olefin of 60/40 to 7
3/27, the molecular weight distribution (Mw / Mn) Q value determined by GPC measurement is less than 4, and the intrinsic viscosity [η] measured in decalin at 135 ° C. is 2.7 to 5.0 dl.
/ G, the iodine value is 10 to 40, and the non-conjugated diene is 5-ethylidene-2-norbornene.
α-olefin / non-conjugated diene copolymer rubber (A): 9
9 to 60% by weight, and ethylene and 3 to 20 carbon atoms
And the molar ratio of ethylene to α-olefin is 50/50 to 7
Liquid ethylene / α-olefin copolymer (B) having an intrinsic viscosity [η] of 0.2 to 0.4 dl / g when measured in decalin at 135 ° C .: 1 to 40% by weight. A rubber composition comprising an ethylene / α-olefin / non-conjugated diene copolymer rubber composition as a main component, wherein the ethylene / α-olefin / non-conjugated diene copolymer is used.
For 100 parts by weight of the rubber composition [I], 0.1 to 10 parts by weight of [II] sulfur and 40 to 120 parts by weight of carbon black [III] are contained.
Has been made, the loss tangent obtained by a dynamic viscoelasticity test of vulcanized (tan
δ) is in the range of 0.15 to 0.35. Wherein said heat-resistant rubber vibration insulator for the rubber composition, heat rubber cushion rubber composition according to claim 1, characterized in that the automotive engine mount insulator rubber composition. Wherein said heat-resistant rubber vibration insulator for the rubber composition, heat rubber cushion rubber composition according to claim 1, characterized in that the car center bearing insulator rubber composition. Wherein said heat-resistant rubber vibration insulator for the rubber composition, heat anti-vibration rubber of <br/> claim 1, characterized in that the insulator rubber composition for automotive rack and pinion steering device Rubber composition.