JPH061893A - Rubber composition for heat-resistant anti-vibration rubber - Google Patents

Abstract

(57) [Summary] [Structure] Ethylene having a specific ethylene-α-olefin molar ratio, an intrinsic viscosity, a melt flow index at 230 ° C with 50 phr of paraffinic oil extended, and an iodine value. α-olefin / 5-ethylidene-2-norbornene copolymer rubber,
A rubber composition containing sulfur and carbon black as main components, wherein a loss tangent (tan δ) obtained by a dynamic viscoelasticity test after vulcanization falls within a specific range. Rubber composition. [Effect] The rubber composition of the present invention has the same vibration-damping properties and durability as natural rubber-based vibration-damping rubbers, and also has heat resistance and vibration resistance for automobiles superior to that of natural rubber-based materials. Can be provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat and vibration resistant rubber composition, and more particularly to an anti-vibration rubber composition for automobile engine mount insulators, center bearing insulators, rack and pinion type steering device insulators, etc. The present invention relates to a heat-resistant vibration-proof rubber composition that can be suitably used as a vibration-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 properties. That is, in recent years, as a result of the reduction of the heat radiation space in the engine room and the increase in the output of the engine in automobiles, the atmospheric temperature in the engine room tends to rise, and the thermal environment of various anti-vibration rubbers is It's getting tougher. Examples of various anti-vibration rubbers include rubbers used for engine mount insulators, center bearing insulators, rack and pinion type steering device insulators (hereinafter sometimes referred to as rack mount insulators), and the like. Hereinafter, each of these insulators will be described.

First, in the engine mount insulator, in addition to the function of supporting most of the load of the engine and the function of supporting the torque reaction force generated by the engine, it is required to satisfy good soundproofing and antivibration characteristics. It Conventionally, engine mount insulators have been mainly made of natural rubber having appropriate vibration damping performance and excellent fatigue resistance (durability). In some cases, butadiene rubber, styrene-butadiene rubber, chloroprene rubber are used. , Butyl rubber, etc. are used alone or in many cases blended with natural rubber (hereinafter,
Natural rubber-based material).

However, as described above, at present, the heat environment in the engine room is deteriorated, in terms of heat resistance,
Natural rubber materials are reaching their limits. On the other hand, butadiene rubber and styrene-butadiene rubber alone have problems that durability is inferior to natural rubber and heat resistance is not sufficient. Further, chloroprene rubber is inferior in low-temperature flexibility, and is therefore unsuitable for vibration-proof rubber applications. Although butyl rubber is excellent in damping performance, it has a fundamental problem of extremely high dynamic magnification and also has a problem of inferior durability to natural rubber. Although conventional ethylene / propylene rubber has excellent heat resistance, it has a drawback that durability is inferior to that of natural rubber.

Also in the center bearing insulator of the automobile, the thermal environment is deteriorated as in the case of the engine mount insulator described above, and the conventional center bearing insulator cannot satisfy the heat resistance. This center bearing insulator is located at the center of the propeller shaft of FR and 4WD vehicles and is used for the 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 also plays a role in controlling and supporting the behavior of the propeller shaft. Conventionally, since the center bearing insulator is required to have high strength and low fatigue strength, a natural rubber material has been used. Since the conventional center bearing insulator is a natural rubber-based material, it suffers from severe heat aging in a heat environment exceeding 100 ° C and cannot be put to practical use. Further, as a method of improving the heat resistance of the natural rubber 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, although such a method improves the heat resistance of the natural rubber-based material, the improvement effect is about 10 ° C. and there is a drawback that the durability is deteriorated, so that the required quality cannot be satisfied. There wasn't.

[0006] Chloroprene rubber, ethylene-propylene rubber, butyl rubber and the like have been conventionally known as raw material rubbers having heat resistance superior to that of natural rubber materials, but these rubbers have the above-mentioned problems. There is no fault.

Further, in the rack mount insulator of the automobile, the thermal environment 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 cannot be satisfied. There is.

The rack mount insulator is used for a fastening portion between the steering wheel and the rack and prevents vibrations from the tires from being directly transmitted to the steering wheel through the rack, and also has a good effect on the sensitivity of the steering wheel. Is responsible for Therefore, rack mount insulators are required to have appropriate 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. Has been done.

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

Therefore, the appearance of a rubber composition for heat-resistant anti-vibration rubber, which has the same level of anti-vibration properties and durability as the natural rubber-based anti-vibration rubber, and has heat resistance superior to that of the natural rubber-based material, has been developed. Was wanted.

[0011]

SUMMARY OF THE INVENTION The present invention is intended to solve the problems associated with the prior art as described above, and has the same level of vibration damping characteristics and durability as natural rubber vibration damping rubber.
An object of the present invention is to provide a rubber composition for a heat and vibration resistant rubber, which can provide a vibration resistant rubber having heat resistance superior to that of a natural rubber material.

[0012]

SUMMARY OF THE INVENTION A rubber composition for a heat and vibration resistant 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 α-
The molar ratio with the olefin is 65/35 to 73/27, the intrinsic viscosity [η] measured in decalin at 135 ° C. is 3.7 to 4.2 dl / g, and the paraffin oil is extended by 50 phr. Has a melt flow index of 0.2 to 0.5 g / 10 minutes at 230 ° C.,
100 parts by weight of an ethylene / α-olefin / non-conjugated diene copolymer rubber having an iodine value of 10 to 25 and a non-conjugated diene of 5-ethylidene-2-norbornene;
A rubber composition mainly comprising [I] 0.1 to 10 parts by weight of sulfur and [III] carbon black of 25 to 100 parts by weight, and having a loss tangent (determined by a dynamic viscoelasticity test after vulcanization ( It is characterized in that tan δ) is 0.03 to 0.15.

The rubber composition for an automobile engine mount insulator 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. Has a molar ratio of 65/35 to 73/27, an intrinsic viscosity [η] measured in decalin at 135 ° C. of 3.7 to 4.2 dl / g, and a paraffinic oil in an oil extended state of 50 phr. Melt flow index at 230 ° C is 0.2
To 0.5 g / 10 minutes, the iodine value is 10 to 25, and the non-conjugated diene is 5-ethylidene-2-norbornene, 100 parts by weight of ethylene / α-olefin / non-conjugated diene copolymer rubber, A rubber composition comprising [II] 0.1 to 10 parts by weight of sulfur and [III] carbon black of 25 to 100 parts by weight as a main component, and a loss tangent obtained by a dynamic viscoelasticity test after vulcanization. (Tan δ) is 0.03
It is characterized by being ~ 0.15.

Further, the rubber composition for an automobile center bearing insulator 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 α-olefin. Has a molar ratio of 65/35 to 73/27 and an intrinsic viscosity [η] measured in 135 ° C. decalin of 3.7 to 4.2 dl /
g, the melt flow index at 230 ° C. of the paraffinic oil extended by 50 phr is 0.2 to 0.5 g / 10 minutes, and the iodine value is 10 to 2
5 and the non-conjugated diene is 5-ethylidene-2-norbornene, 100 parts by weight of an ethylene / α-olefin / non-conjugated diene copolymer rubber, and [II] sulfur 0.1 to 1
0 parts by weight and [III] carbon black 40-100
And a loss tangent (tan δ) determined by a dynamic viscoelasticity test after vulcanization is 0.03 to 0.15.

Furthermore, the rubber composition for an insulator of an automobile rack-and-pinion type steering device according to the present invention comprises [I] ethylene, an α-olefin having 3 to 20 carbon atoms and a non-conjugated diene, and The molar ratio of ethylene to α-olefin is 65/35 to 73 /
27, the intrinsic viscosity [η] measured in decalin at 135 ° C. was 3.7 to 4.2 dl / g, and the melt flow index at 230 ° C. in a state where 50 phr of paraffin oil was oil-extended was 0.2. ~ 0.5 g / 10 min, iodine value is 10 to 25, non-conjugated diene is 5-ethylidene-2-norbornene ethylene.α-
100 parts by weight of olefin / non-conjugated diene copolymer rubber, 0.1 to 10 parts by weight of [II] sulfur, and [III]
A rubber composition containing 40 to 100 parts by weight of carbon black as a main component, which has a loss tangent (tan δ) of 0.03 to 0.15 determined by a dynamic viscoelasticity test after vulcanization. I am trying.

These rubber compositions are heat-resistant and vibration-resistant rubbers for automobiles, which have vibration-proofing properties and durability comparable to those of natural rubber-based vibration-proof rubbers, and have heat resistance superior to that of natural rubber-based materials. Can be provided.

[0017]

DETAILED DESCRIPTION OF THE INVENTION The rubber composition for heat and vibration resistant rubber according to the present invention will be specifically described below. The rubber composition for heat-resistant and vibration-proof rubber according to the present invention comprises [I] specific ethylene
α-olefin / non-conjugated diene copolymer rubber, [I
An unvulcanized rubber composition comprising I] sulfur and [III] carbon black, the loss tangent (tan δ) of which is determined by a dynamic viscoelasticity test after vulcanization falls within a specific range. . This rubber composition can be vulcanized and molded to be used as an insulator (vulcanized rubber). 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-conjugated
Diene Copolymer Rubber The ethylene / α-olefin / non-conjugated diene copolymer rubber is a high molecular weight rubber composed of ethylene, an α-olefin having 3 to 20 carbon atoms and a non-conjugated diene.

This ethylene / α-olefin / non-conjugated diene copolymer rubber has a molar ratio [ethylene / α-olefin] of ethylene and α-olefin of 65/35 to 73.
/ 27. When the above molar ratio is less than 65/35,
The vulcanized rubber of the obtained rubber composition tends to have low strength and low durability. On the other hand, the above molar ratio is 73/2.
When it exceeds 7, the low temperature flexibility of the vulcanized rubber of the obtained rubber composition tends to decrease.

Specific 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, nonadecene-1, eicosene-1 and the like. These α-olefins are used alone or in combination. Of these, propylene is particularly preferable.

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

The ethylene / α-olefin / non-conjugated diene copolymer rubber has an intrinsic viscosity [η] measured in decalin of 135 ° C. of 3.7 to 4.2 dl / g and a paraffin oil. (PW-380; manufactured by Idemitsu Kosan Co., Ltd.) has a melt flow index of 0.2 to 0.5 g / 1 at 230 ° C. in an oil extended state of 50 phr.
It is in the range of 0 minutes. When the intrinsic viscosity [η] of the ethylene / α-olefin / non-conjugated diene copolymer rubber is within the above range,
When the melt flow index is within the range of 0.2 to 0.5 g / 10 minutes, a rubber composition having excellent fatigue resistance can be obtained.

Even if the intrinsic viscosity [η] of the ethylene / α-olefin / non-conjugated diene copolymer rubber is within the above range, the melt flow index is 0.5 g / 1.
If it exceeds 0 minutes, the resulting rubber composition tends to have reduced fatigue resistance in a high temperature atmosphere. When the melt flow index is less than 0.2 g / 10 minutes,
The resulting rubber composition has reduced processability and heat aging resistance,
In particular, the fatigue resistance may be adversely affected.

The above-mentioned ethylene / α-olefin /
Non-conjugated diene copolymer rubbers are, for example, Japanese Patent Publication No. 59-1.
It can be manufactured by the method described in Japanese Patent No. 4497. That is, in the presence of a Ziegler catalyst, hydrogen is used as a molecular weight regulator, and ethylene and C 3 are used.
An ethylene / α-olefin / non-conjugated diene copolymer rubber can be obtained by copolymerizing an α-olefin of about 20 to a diene.

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

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

In the rubber composition for heat and vibration resistant rubber according to the present invention, the carbon black is in the range of 25 to 100 parts by weight based on 100 parts by weight of the ethylene / α-olefin / non-conjugated diene copolymer rubber. Used in.

For example, when the rubber composition for heat-resistant and vibration-proof rubber according to the present invention is used as a rubber composition for automobile engine mount insulator, carbon black is the above-mentioned ethylene / α-olefin / non-conjugated diene copolymer. It is in the range of 25 to 100 parts by weight, preferably 40 to 80 parts by weight, based on 100 parts by weight of rubber. If the compounding amount of carbon black is less than 25 parts by weight, the vulcanized rubber of the obtained rubber composition tends to have deteriorated physical properties. On the other hand, when the blending amount of carbon black exceeds 100 parts by weight, the kneading processability and molding processability of the obtained rubber composition tend to deteriorate.

When the rubber composition for heat and vibration resistant rubber according to the present invention is used as a rubber composition for automobile center bearing insulators or a rubber composition for insulators of automobile rack and pinion type steering devices, carbon black is used. Is ethylene / α
It is in the range of 40 to 100 parts by weight, preferably 50 to 80 parts by weight, based on 100 parts by weight of the olefin / non-conjugated diene copolymer rubber. When the compounding amount of carbon black is less than 40 parts by weight, the vulcanized rubber of the obtained rubber composition has
Since the strength decreases, the durability tends to decrease. On the other hand, when the blending amount of carbon black exceeds 100 parts by weight, the kneading processability and molding processability of the obtained rubber composition tend to deteriorate.

In the present invention, carbon black is present in the unvulcanized rubber composition.
It may be used when vulcanizing the olefin / non-conjugated diene copolymer rubber composition.

Other compounding agents In addition to the above ethylene / α-olefin / non-conjugated diene copolymer rubber, sulfur and carbon black, ethylene / propylene rubber or the like is added to the rubber composition for heat and vibration resistant rubber of the present invention. Compounding agents such as vulcanization accelerators, vulcanization aids, and softeners that have been widely and conventionally used in the production of vulcanized rubber molded articles can be used within the range that does not impair the object of the present invention.

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, di Guanidine compounds such as orthotolyl guanidine, orthotolyl by guanide, diphenylguanidine phthalate; aldehydes such as acetaldehyde-aniline reaction product, butyraldehyde-aniline condensate, hexamethylenetetramine, acetaldehyde-ammonia reaction product-amine or aldehyde- Ammonia-based compounds; 2-mercaptoimidazoline and other imidazoline-based compounds; Thiocarbanilide, diethylthiourea, dibutylthiourea, trimethylthiourea, diorthotolylthiourea, etc. 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-based compounds such as selenium dimethyldithiocarbamate and tellurium diethyldithiocarbamate; xanthate-based compounds such as zinc dibutylxanthate; and other compounds such as zinc white.

These vulcanization accelerators are the above-mentioned ethylene / α
-0.1 to 20 parts by weight, preferably 0.2 to 1 part by weight with respect to 100 parts by weight of olefin / non-conjugated diene copolymer rubber
Used in a proportion of 0 parts by weight.

As the above-mentioned softening agent, a softening agent generally used for rubber is used. Specifically, petroleum-based softening agents such as process oil, lubricating oil, paraffin, liquid paraffin, petroleum asphalt and petrolatum; coal. Coal tar type softeners such as tar and coal tar pitch; Fat oil type 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 resin, atactic polypropylene, coumarone indene resin Synthetic polymer substances such as are used. Of these, petroleum-based softeners are preferably used, and process oils are particularly preferably used.

The rubber composition for heat and vibration resistant 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 and the softening agent are kneaded at a temperature of 80 to 170 ° C. for 3 to 10 minutes, and then an open roll or the like is used. Using rolls, sulfur as a vulcanizing agent, carbon black, and optionally a vulcanization accelerator or vulcanization aid are additionally mixed, and kneaded at a roll temperature of 40 to 80 ° C. for 5 to 30 minutes, and then kneaded. The material is extruded to prepare a ribbon-shaped or sheet-shaped compounded rubber.

The rubber composition for heat and vibration resistant rubber of the present invention has a loss tangent (tan) determined by a dynamic viscoelasticity test after vulcanization.
It has a composition such that δ) is 0.03 to 0.15. 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 automobile rack and pinion steering device insulator of the present invention are obtained by a dynamic viscoelasticity test after vulcanization. The composition has a loss tangent (tan δ) of 0.03 to 0.15.

Production of Vulcanized Rubber To obtain a vulcanized rubber from the rubber composition for heat-resistant and vibration-proof rubber according to the present invention, the unvulcanized rubber may be 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, calender roll, or press, and at the same time as molding or by introducing the molded product into a vulcanization tank, 130 to 270 ° C. It is heated 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.

[0039]

The rubber composition according to the present invention comprises a specific ethylene / α-olefin / non-conjugated diene copolymer rubber,
Since it contains sulfur and carbon black in a specific ratio and has a loss tangent (tan δ) determined by a dynamic viscoelasticity test after vulcanization within a specific range, it is the same as natural rubber-based anti-vibration rubber. In addition to having a level of anti-vibration properties and durability,
It is possible to provide an anti-vibration rubber for automobiles having heat resistance superior to that of a natural rubber material.

The present invention will be described below with reference to examples.
The present invention is not limited to these examples. In addition, the test method performed about the insulator (vulcanized rubber) in an Example and a comparative example is as follows.

[1] Rubber physical property test The rubber physical property test is conducted in accordance with JIS K 6301. Tensile strength, elongation, tear strength and rubber hardness (J
The IS A hardness) was determined.

[2] Gehman low temperature torsion test The Gehman low temperature torsion test is conducted according to JIS K 6301 (19).
1989), T ₂ [unit: ° C], T
₁₀ [Unit: ° C] was determined.

[3] Product durability test of engine mount insulator In the product durability test, an initial load of 90 kg in the P direction was applied to the insulator 2 of the automobile engine mount 1 shown in FIGS. 1 to 3 which was heat aged under the following conditions. After loading, the insulator 2 under the condition of a constant load of ± 180kg
The number of times of rupture was measured by repeating the process until rupture. The ambient temperature for this test was room temperature. Other test conditions are as follows.

Heat aging conditions: 120 ° C., 72 hours, vibration frequency: 5 Hz, 2 Hz The number of breaks is 6, and the average of four breaks excluding the minimum and maximum values of these breaks. It is a value.

[4] Product durability test of center bearing insulator The product durability test is shown in FIG.
Propeller shaft 3 fastened with is ± 10mm in Q direction
While moving, it was performed at 120 ° C. and 140 ° C. at a vibration frequency of 7 Hz until the insulator 5 was broken, and the number of times of breaking was measured. The ambient temperature of this test is
The number of breaks is 100 ° C., the number of breaks is 6, and the average value of four breaks excluding the minimum and maximum values of these breaks.

[5] Product fatigue test of center bearing insulator In the product fatigue test, the amount of fatigue of the insulator 5 heat-aged at 100 ° C. for 300 hours under a load of 7 kg in FIG. The amount of settling of the insulator 5 heat-aged for 1,000 hours was measured. The atmospheric temperature of this test is 100 ° C.

[6] Product durability test of rack mount insulator In the product durability test, the rack mount insulator 6 shown in FIGS. 5 and 6 is attached with jigs 7 and 8 as shown in FIG. 7, and the temperature is room temperature and 120 ° C. ± 600 in P direction under atmosphere
After applying a constant load of kg and vibrating 100,000 times at a vibration frequency of 3 Hz, the rate of change of the static spring constant was measured.

[7] 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 )
Then, the loss tangent tan δ (index of vibration damping) was calculated by the following formula.

G _s = G ′ + ιG ″ (G _s : static shear modulus, real number G ′: dynamic shear modulus,
Imaginary number G ″: dynamic loss elastic modulus) tan δ = G ″ / G ′ [Examples and comparative examples of rubber compositions for engine mount insulators]

[0050]

Comparative Examples 1 to 6 100 parts by weight of EPDM shown in Table 1, 0.5 parts by weight of sulfur and carbon black [N55
0] 60 parts by weight, zinc oxide 5 parts by weight, stearic acid 1 part by weight, and paraffinic process oil (softening agent) 5
4.3 parts of 0 parts by weight, 3 parts by weight of vulcanization accelerator (A), 1.5 parts by weight of vulcanization accelerator (B), and 0.75 parts by weight of vulcanization accelerator (C) The mixture was kneaded with a high capacity Banbury mixer [manufactured by Kobe Steel Ltd.].

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

[0052]

Comparative Example 7 70 parts by weight of natural rubber (NR) [RSS No. 1], 30 parts by weight of styrene-butadiene rubber (SBR) [manufactured by Nippon Zeon Co., Ltd., trade name: Nipol 1502], and sulfur 1.5. Parts by weight and carbon black [N
550] 45 parts by weight, zinc oxide 5 parts by weight, stearic acid 1 part by weight, and aroma process oil (softening agent) 1
2.5 parts by weight, 1.5 parts by weight of vulcanization accelerator (D), 0.3 parts by weight of vulcanization accelerator (C), and 5 parts by weight of antioxidants were added to a 4.3 liter capacity. It was kneaded with a Banbury mixer (manufactured by Kobe Steel, Ltd.).

From the kneaded product thus obtained, test pieces for the above various tests were prepared and tested. The results are shown in Table 1.

[0054]

Examples 1 to 3 In Comparative Example 1, the EPD of Comparative Example 1
Except that EPDM shown in Table 1 was used instead of M,
The same procedure as in Comparative Example 1 was performed.

The results are shown in Table 1.

[0056]

Example 4 In Comparative Example 1, the EPDM shown in Table 1 was used in place of the EPDM of Comparative Example 1, and the compounding amounts of sulfur, carbon black and paraffin-based process oil were 1.5 parts by weight, respectively. 40 parts by weight, 30
The same procedure as in Comparative Example 1 was performed except that the weight part was changed.

The results are shown in Table 1.

[0058]

[Table 1]

[0059]

[Table 2]

From Table 1, the following can be understood. In Comparative Examples 1 and 4, EPDM has a low intrinsic viscosity and poor fatigue resistance, and therefore the durability of the engine mount insulator is also poor.

In Comparative Examples 2 and 3, since the ethylene content of EPDM is too high, the low temperature flexibility of the engine mount insulator is poor. Furthermore, although the intrinsic viscosity [η] of EPDM is 3.8 dl / g, in Comparative Example 5 in which the melt flow index is 0.1 g / 10 min, the processability is poor and the dispersibility of additives such as carbon black is poor. And the heat aging resistance also deteriorates, resulting in extremely poor fatigue test results.

The intrinsic viscosity [η] of EPDM is 3.7.
Although it is dl / g, the melt flow index is 0.
In Comparative Example 6 of 6 g / 10 minutes, the fatigue resistance after heat aging is poor.

Furthermore, the natural rubber engine mount insulator of Comparative Example 7 exhibits excellent durability when not heat aged, but extremely durable when heat aged at 120 ° C. It is falling.

In contrast to the engine mount insulator of the comparative example described above, the engine mount insulators of Examples 1 to 3 all exhibit excellent heat resistance durability and low temperature flexibility.

Further, as shown in Example 4, when the amount of carbon black is reduced, the durability tends to decrease.
[Rubber composition for center bearing insulators]

[0066]

Comparative Examples 8 to 13 100 parts by weight of EPDM shown in Table 2, 0.5 parts by weight of sulfur, and carbon black [N55
0] 65 parts by weight, zinc oxide 5 parts by weight, stearic acid 1 part by weight, paraffinic process oil 50 parts by weight, vulcanization accelerator (A) 3.0 parts by weight, vulcanization accelerator (B ) 1.5 parts by weight and 0.75 parts by weight of the vulcanization accelerator (C) were kneaded with a Banbury mixer (produced by Kobe Steel, Ltd.) having a capacity of 4.3 liters.

From the kneaded product thus obtained, test pieces for the above-mentioned various tests were prepared and subjected to the above-mentioned various tests.
The results are shown in Table 2.

[0068]

[Comparative Example 14] Natural rubber (NR) [RSS No. 1] 70
Parts by weight and styrene-butadiene rubber (SBR) [manufactured by Nippon Zeon Co., Ltd., trade name: Nipol 1502] 30
Parts by weight, sulfur 1.5 parts by weight, carbon black [N550] 55 parts by weight, zinc oxide 5 parts by weight, stearic acid 1 part by weight, aroma-based process oil 20 parts by weight, and antioxidants 5 Parts by weight and vulcanization accelerator (D) 1.
3. 5 parts by weight and 0.3 part by weight of the vulcanization accelerator (C) were added.
The mixture was kneaded with a 3 liter Banbury mixer [manufactured by Kobe Steel, Ltd.].

From the kneaded product thus obtained, test pieces for the above various tests were prepared and tested. The results are shown in Table 2.

[0070]

Example 5 In Comparative Example 8, the EPDM shown in Table 2 was used instead of the EPDM of Comparative Example 8, and the blending amounts of sulfur, carbon black and paraffin-based process oil were 1.5 parts by weight, respectively. 45 parts by weight, 30
The same procedure as in Comparative Example 8 was performed except that the weight part was changed.

The results are shown in Table 2.

[0072]

Examples 6 to 8 In Comparative Example 8, the EPD of Comparative Example 8
Instead of M, EPDM shown in Table 2 was used.
The same procedure as in Comparative Example 8 was performed.

The results are shown in Table 2.

[0074]

[Table 3]

[0075]

[Table 4]

From Table 2, the following can be understood. In Comparative Example 8, since the molecular weight of EPDM is small as can be seen from the intrinsic viscosity, the durability of the center bearing insulator is poor.

In Comparative Examples 9 and 10, EPDM was used.
Since the ethylene content is too high, the center bearing insulator is poor in low-temperature flexibility, and EPDM has a slightly low intrinsic viscosity, so that the durability of the center bearing insulator is poor. The durability of the center bearing insulator of Comparative Example 10 is inferior to that of the center bearing insulator of Comparative Example 9 because EPDM of Comparative Example 10 has a higher iodine value and inferior heat resistance than EPDM of Comparative Example 9. Is considered to be.

The EPDM of Comparative Example 11 is the E of Comparative Example 8.
Since the intrinsic viscosity is higher than that of PDM, the center bearing insulator of Comparative Example 11 has improved durability as compared with the center bearing insulator of Comparative Example 8. However, the durability of the center bearing insulator of Comparative Example 11 is not yet at a satisfactory level.

Furthermore, the intrinsic viscosity [η] of EPDM is 3.
In Comparative Example 12 having a melt flow index of 0.1 g / 10 min, although it is 8 dl / g, the processability is poor and the dispersibility of additives such as carbon black is poor, and the heat aging resistance is also poor. Especially the fatigue test results are poor.

The intrinsic viscosity [η] of EPDM is 3.7.
Although it is dl / g, the melt flow index is 0.
In Comparative Example 13 of 6 g / 10 minutes, the fatigue resistance after heat aging is poor.

In contrast to the center bearing insulator of the above comparative example, the center bearing insulators of Examples 6 to 8 all exhibit excellent heat sink resistance and durability, and low temperature flexibility is also satisfactory as a vibration isolating rubber. Shows performance.

Although Example 5 is an example in which the amount of carbon black is smaller than that of Examples 6 to 8, it is possible to maintain sufficient durability if the amount of carbon black is 40 phr or more. Shows.

Comparative Example 14 is an example in which a natural rubber type rubber composition which is usually used for the center bearing insulator is used, but the center bearing insulator of Comparative Example 14 has a heat resistance, and therefore the above Example 5 is used. ~ 8
Clearly inferior to the center bearing insulator.

[Rubber Composition for Rack Mount Insulator]

[0085]

Comparative Example 15 Natural Rubber (NR) [RSS No. 1] 70
Parts by weight and styrene-butadiene rubber (SBR) [manufactured by Nippon Zeon Co., Ltd., trade name: Nipol 1502] 30
Parts by weight, 1.5 parts by weight of sulfur, 55 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 process oil, and vulcanization accelerator ( D) 1.5 parts by weight, vulcanization accelerator (C) 0.3 parts by weight, and antioxidants 5 parts by weight,
The mixture was kneaded with a Banbury mixer (manufactured by Kobe Steel, Ltd.) having a capacity of 4.3 liters.

From the kneaded product thus obtained, test pieces for the above-mentioned vulcanized rubber hardness test, Gehman low temperature twist test and product durability test were prepared and tested. The results are shown in Table 3.

[0087]

[Comparative Examples 16 to 19 and Examples 9 to 10] 100 parts by weight of EPDM shown in Table 3, 0.5 parts by weight of sulfur, carbon black [N550] the amount shown in Table 3, and 5 parts by weight of zinc oxide. , 1 part by weight of stearic acid, the amount of paraffinic process oil shown in Table 3, and vulcanization accelerator (A) 3
Parts by weight, 0.75 parts by weight of vulcanization accelerator (C) and 1.5 parts by weight of vulcanization accelerator (B) with a 4.3 liter capacity Banbury mixer [Kobe Steel Co., Ltd.]. Kneaded in.

From the kneaded product thus obtained, test pieces for the above-mentioned vulcanized rubber hardness test, Gehman low temperature twist test and product durability test were prepared and tested. The results are shown in Table 3.

In Comparative Example 18, the EPDM of the present invention was used as the raw material rubber and the compounding amount of carbon black was set to 20 parts by weight. However, the kneading operation became impossible and the subsequent experiments could not be performed.

[0090]

[Table 5]

From Table 3, the following can be understood. In Comparative Examples 15, 17 and 19, the rate of change of the static spring constant is large and the product durability is insufficient.

In Comparative Example 16, low temperature flexibility is insufficient. In Comparative Example 18, as described above, the kneading operation is impossible and cannot be put to practical use.

In contrast to the above Comparative Example, Examples 9 and 10 showed satisfactory performance in workability, low temperature flexibility and product durability.

[Brief description of drawings]

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

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

3 is a view of the engine mount A- in FIG.
FIG.

FIG. 4 is a schematic cross-sectional view showing a state where the automobile center bearing insulator manufactured in Examples and Comparative Examples is 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 steering device manufactured in Examples and Comparative Examples.

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

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

[Explanation 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

[Procedure amendment]

[Submission date] July 10, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction content]

[II] Sulfur The 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. In the present invention, sulfur is present in the unvulcanized rubber composition, but it may be used when vulcanizing the ethylene / α-olefin / non-conjugated diene copolymer rubber.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Norihiro Harada 330 Naganuma-cho, Inage-ku, Chiba-shi, Chiba Kinugawa Rubber Industry Co., Ltd. (72) Hiroshi Toriyabe 330 Naganuma-cho, Inage-ku, Chiba, Chiba Kinugawa Rubber Industry Co., Ltd.

Claims (4)

[Claims] 1. [I] ethylene and α having 3 to 20 carbon atoms
-Consisting of olefin and non-conjugated diene, and the molar ratio of ethylene and α-olefin is 65/35 to 73/2
7, the intrinsic viscosity [η] measured in decalin at 135 ° C. was 3.7 to 4.2 dl / g, and the melt flow index at 230 ° C. in the state where 50 phr of paraffin oil was oil-extended was 0.2. ~ 0.5 g / 10 min, iodine value is 10 to 25, non-conjugated diene is 5-ethylidene-2-norbornene ethylene.α-
100 parts by weight of olefin / non-conjugated diene copolymer rubber, 0.1 to 10 parts by weight of [II] sulfur, and [III]
A rubber composition containing 25 to 100 parts by weight of carbon black as a main component, which has a loss tangent (tan) determined by a dynamic viscoelasticity test after vulcanization.
δ) is 0.03 to 0.15, a rubber composition for heat and vibration resistant rubber. 2. [I] ethylene and α having 3 to 20 carbon atoms
-Consisting of olefin and non-conjugated diene, and the molar ratio of ethylene and α-olefin is 65/35 to 73/2
7, the intrinsic viscosity [η] measured in decalin at 135 ° C. was 3.7 to 4.2 dl / g, and the melt flow index at 230 ° C. in the state where 50 phr of paraffin oil was oil-extended was 0.2. ~ 0.5 g / 10 min, iodine value is 10 to 25, non-conjugated diene is 5-ethylidene-2-norbornene ethylene.α-
100 parts by weight of olefin / non-conjugated diene copolymer rubber, 0.1 to 10 parts by weight of [II] sulfur, and [III]
A rubber composition containing 25 to 100 parts by weight of carbon black as a main component, which has a loss tangent (tan) determined by a dynamic viscoelasticity test after vulcanization.
A rubber composition for an automobile engine mount insulator, wherein δ) is 0.03 to 0.15. 3. [I] ethylene and α having 3 to 20 carbon atoms
-Consisting of olefin and non-conjugated diene, and the molar ratio of ethylene and α-olefin is 65/35 to 73/2
7, the intrinsic viscosity [η] measured in decalin at 135 ° C. was 3.7 to 4.2 dl / g, and the melt flow index at 230 ° C. in the state where 50 phr of paraffin oil was oil-extended was 0.2. ~ 0.5 g / 10 min, iodine value is 10 to 25, non-conjugated diene is 5-ethylidene-2-norbornene ethylene.α-
100 parts by weight of olefin / non-conjugated diene copolymer rubber, 0.1 to 10 parts by weight of [II] sulfur, and [III]
A rubber composition containing 40 to 100 parts by weight of carbon black as a main component, which has a loss tangent (tan) determined by a dynamic viscoelasticity test after vulcanization.
δ) is 0.03 to 0.15, a rubber composition for automobile center bearing insulators. 4. [I] ethylene and α having 3 to 20 carbon atoms
-Consisting of olefin and non-conjugated diene, and the molar ratio of ethylene and α-olefin is 65/35 to 73/2
7, the intrinsic viscosity [η] measured in decalin at 135 ° C. was 3.7 to 4.2 dl / g, and the melt flow index at 230 ° C. in the state where 50 phr of paraffin oil was oil-extended was 0.2. ~ 0.5 g / 10 min, iodine value is 10 to 25, non-conjugated diene is 5-ethylidene-2-norbornene ethylene.α-
100 parts by weight of olefin / non-conjugated diene copolymer rubber, 0.1 to 10 parts by weight of [II] sulfur, and [III]
A rubber composition containing 40 to 100 parts by weight of carbon black as a main component, which has a loss tangent (tan) determined by a dynamic viscoelasticity test after vulcanization.
δ) is 0.03 to 0.15, a rubber composition for an insulator of an automobile rack-and-pinion steering device.