JP2528224B2 - Rubber composition for heat-resistant anti-vibration rubber - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a rubber composition for heat-resistant and vibration-proof rubber, and more specifically, it is suitable for use as a vibration-proof rubber material required to have heat resistance particularly in engine mounts of automobiles. The present invention relates to a rubber composition for rubber.

[0002]

BACKGROUND OF THE INVENTION In recent years, the physical properties required for anti-vibration rubber, particularly heat resistance and anti-vibration properties, have become extremely severe.

Polymers currently used for anti-vibration rubber are natural rubber (NR), butadiene rubber (BR), styrene-butadiene rubber (SBR), chloroprene rubber (C).
R), butyl rubber (IIR), etc. are used, and two or more polymers are blended and used depending on the application. However, these polymers basically have poor heat resistance because they have a double bond in the main chain. Therefore, attempts have been made to control the cross-linking form by studying the type and combination of vulcanization accelerators, but under the condition of being exposed to a high temperature of 120 ° C. or higher for a long time, such as in an engine room of an automobile. The surface of the anti-vibration rubber may crack and eventually break. Therefore, in the anti-vibration rubber, improvement in heat resistance is a problem.

The anti-vibration property is an important physical property because it is largely related to the riding comfort of the vehicle and the muffled noise in the vehicle.
The engine mount acts as a dynamic damper for the engine transmission and reduces the vibration of the vehicle body due to input from the road surface.Recently, it lowers the low range such as idle vibration, shake, and muffled sound at a higher level. Is desired. For example, it is required to reduce the transmission rate in the frequency band of 100 Hz or higher for vehicle interior noise such as muffled noise while suppressing vibration transmission in the frequency band of 7 to 15 Hz related to engine shake.

Therefore, in order to attenuate a high-amplitude input at a low frequency (7 to 15 Hz), the loss tangent (tan δ), which is a measure of the riding comfort of an automobile, should be increased.
A polymer having a large an δ or a compound thereof has a large dynamic ratio (dynamic shear modulus / static shear modulus), which causes a problem that muffled noise is generated during high-speed operation. Further, although the liquid-filled type vibration-proof rubber exhibits excellent vibration-proof properties, it has a drawback that the structure is complicated and the cost is significantly increased.

Therefore, a vulcanized rubber which has solved the above problems and has excellent properties such as heat resistance and anti-vibration properties, and in which the rate of change in anti-vibration properties due to heat deterioration is small, that is, excellent in heat aging resistance. It has long been desired to develop a rubber composition for a heat and vibration resistant rubber that can provide a molded product.

[0007]

It is an object of the present invention to solve the problems associated with the prior art as described above, and to provide a vulcanizate having excellent properties such as heat resistance and anti-vibration properties as well as heat aging resistance. It is an object of the present invention to provide a rubber composition for heat-resistant and vibration-proof rubber, which can give a rubber molded body.

[0008]

SUMMARY OF THE INVENTION A rubber composition for heat and vibration resistant rubber according to the present invention comprises ethylene, an α-olefin having 3 to 20 carbon atoms and a non-conjugated diene, and has an ethylene content of 60 to 60%.
73 mol%, the molecular weight distribution (Mw / Mn) Q value determined by GPC method is less than 4, and the intrinsic viscosity [η] measured in decalin at 135 ° C. is 2.7 to 5.0 d.
ethylene having an iodine value of 10 to 40, which is 1 / g.
High molecular weight component (A) consisting of α-olefin / diene copolymer rubber: 90 to 60% by weight, consisting of ethylene and α-olefin having 3 to 20 carbon atoms, and having an ethylene content of 50 to 78 mol. %, And the intrinsic viscosity [η] measured in decalin at 135 ° C. is 0.2 to 0.4 dl /
a low molecular weight component (B) consisting of a liquid ethylene / α-olefin copolymer of g: 10 to 40% by weight ,
Ethylene / α-olefi with immodal molecular weight distribution
Containing ethylene -diene rubber as the main component
Mooney viscosity of fin-diene rubber ML _{1 + 4} (100
C) is in the range of 20 to 150, and the ethylene / α-
Molecular weight of olefin / diene rubber 3,000-
Iodine number (IV ₁ ) and molecule in the low molecular weight region of 15,000
Iodine in the high molecular weight range of 80,000 to 120,000
It is characterized in that the ratio (IV ₁ / IV ₂ ) to the value (IV ₂ ) is 0.1 or less.

[0009]

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 and vibration resistant rubber according to the present invention contains a specific ethylene / α-olefin / diene rubber as a main component. This ethylene / α-olefin / diene rubber is
It is composed of a high molecular weight component (A) composed of an α-olefin / diene copolymer rubber and a low molecular weight component (B) composed of a specific liquid ethylene / α-olefin copolymer.

High molecular weight component (A) The high molecular weight component (A) used in the present invention is an ethylene / α-olefin / diene co-polymer comprising ethylene, an α-olefin having 3 to 20 carbon atoms and a non-conjugated diene. It is a united rubber.

The ethylene / α-olefin / diene copolymer rubber used in the present invention has an ethylene content of 60 to 7
It is 3 mol%, preferably 65 to 70 mol%. 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. Among these, especially propylene and butene-1
Is preferred.

Specific examples of the non-conjugated diene include 1,4-hexadiene, 1,6-octadiene and 2-methyl-diene.
1,5-hexadiene, 6-methyl-1,5-heptadiene, 7-
Chain-like non-conjugated dienes such as methyl-1,6-octadiene, cyclohexadiene, dicyclopentadiene, methyltetrahydroindene, 5-vinylnorbornene, 5-ethylidene
-2-norbornene, 5-methylene-2-norbornene, 5-isopropylidene-2-norbornene, 6-chloromethyl-5-
Cyclic non-conjugated dienes such as isopropenyl-2-norbornene, 2,3-diisopropylidene-5-norbornene, 2-ethylidene-3-isopropylidene-5-norbornene, 2-propenyl-2,2-norbornadiene, 1, Trienes such as 3,7-octatriene and 1,4,9-decatriene can be mentioned. Of these, 1,4-hexadiene and cyclic non-conjugated dienes, particularly dicyclopentadiene and 5-ethylidene-2-norbornene are preferably used.

Further, ethylene / α-used in the present invention
The olefin / diene copolymer rubber has an iodine value of 10 to 40, preferably 15 which is an index of the content of non-conjugated diene.
~ 25.

The ethylene / α-olefin / diene copolymer rubber used in the present invention has a molecular weight distribution (Mw / Mn) Q value determined by GPC measurement of less than 4, preferably 3 or less. By using the ethylene / α-olefin / diene copolymer rubber having such a molecular weight distribution as the high molecular weight component (A), excellent shape retention during vulcanization, mechanical strength characteristics and low compression set are obtained. It is possible to obtain an ethylene / α-olefin diene rubber capable of providing a vulcanized rubber molded product having excellent strain characteristics, dynamic fatigue resistance, and wear resistance.

Further, ethylene / α-used in the present invention
The olefin / diene copolymer rubber has an intrinsic viscosity [η] measured in decalin at 135 ° C. of usually 2.7 dl / g or more, preferably 2.7 to 5.0 dl / g, more preferably 3.5 to 4 It is 0.5 dl / g. When an ethylene / α-olefin / diene copolymer rubber having an intrinsic viscosity [η] in the above range is used, an ethylene / α-olefin diene rubber having excellent dynamic fatigue resistance can be obtained.

Molecular weight distribution (Mw / Mn) Q as described above
Among the ethylene / α-olefin / diene copolymer rubbers having values, the ethylene / α-olefin / diene rubbers obtained by using the ethylene / α-olefin / diene copolymer rubbers having the above-mentioned intrinsic viscosity Shows a remarkable effect of improving the above physical properties.

The above-mentioned ethylene / α-olefin /
The diene copolymer rubber is, for example, Japanese Patent Publication Sho 59-1449.
It can be produced by the method described in Japanese Patent Publication No. That is, in the presence of a Ziegler catalyst, hydrogen is used as a molecular weight regulator, and ethylene and C 3-20 are used.
By copolymerizing α-olefin with a diene of
An ethylene / α-olefin / diene copolymer rubber can be obtained.

Low molecular weight component (B) The low molecular weight component (B) used in the present invention is a liquid ethylene / α-olefin copolymer comprising ethylene and an α-olefin having 3 to 20 carbon atoms, and a diene Contains no ingredients.

The above liquid ethylene / α-olefin copolymer is a random copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms. 3 to 3 carbon atoms
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 and butene-1 are particularly preferable.

In the present invention, the high molecular weight component has the effect of improving heat resistance, mechanical strength characteristics, low compression set characteristics, dynamic fatigue resistance, wear resistance, shape retention, etc. The quality of the molecular weight component was designed so as to be effective in improving vibration-damping properties, heat aging resistance, processability (fluidity), and surface smoothness of the vulcanized rubber molding.

However, ethylene, which is merely bimodal, that is, which exhibits a molecular weight distribution with two modes,
In the α-olefin / diene rubber, since the ratio of the effect of improving the physical properties by the high molecular weight component and the ratio of the effect of improving the properties by the low molecular weight component are in a tug of war,
For example, even if the amount of low molecular weight components is increased and the processability is excellent,
It is not possible to provide a vulcanized rubber molded product having dramatically improved physical properties such as fatigue resistance.

Therefore, the inventors of the present invention further conducted extensive studies on this low molecular weight component, and found that when a vulcanized rubber molded product was obtained from an ethylene / α-olefin / diene rubber showing a bimodal molecular weight distribution. The inventors have found that it is necessary that the low molecular weight component constituting the vulcanized rubber molded body is 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 ethylene content of the liquid ethylene / α-olefin copolymer used in the present invention is usually 50 to 78 mol%, preferably 50 to 70 mol%, more preferably 50 to 60 mol%. . Since the liquid ethylene / α-olefin copolymer having an ethylene content in the above range has good thermal stability, the amount may be reduced during the kneading operation with the above high molecular weight component (A). It does not occur and does not carbonize during molding to contaminate the molded product.

The low molecular weight component (B) used in the present invention,
That is, the liquid ethylene / α-olefin copolymer has 1
The intrinsic viscosity [η] measured in decalin at 35 ° C is 0.2 to
0.4 dl / g, preferably 0.24 to 0.4 dl / g
Is.

When a liquid ethylene / α-olefin copolymer having an intrinsic viscosity [η] in the narrow range as described above is used as a low molecular weight component (B), ethylene / α-olefin excellent in processability (fluidity) is obtained. Olefin / diene rubber can be provided, and since tan δ can be increased without changing the dynamic magnification, the vibration transmissibility related to engine shake can be reduced and the muffled noise during high speed operation can be prevented. can do. Since the dynamic ratio depends on the product hardness, it is important to design the ratio of carbon and oil, and the lower limit strength (hardness) that can safely support the target vibration support is designed. The above characteristics are exhibited at any hardness designed there.

The liquid ethylene / α-olefin copolymer as the low molecular weight component (B) used in the present invention has poor processability (fluidity) when the intrinsic viscosity [η] is less than 0.2 dl / g. Become. On the other hand, when the intrinsic viscosity [η] of the liquid ethylene / α-olefin copolymer exceeds 0.4 dl / g, it becomes impossible to reduce vibration at resonance and prevent muffled noise at high speed operation.

The above-mentioned liquid ethylene / α-olefin copolymer is similar in composition to oil, but has a limiting viscosity [η] in the range of 0.2 to 0.4 dl / g. In the α-olefin copolymer, even if the high molecular weight component (A) used in combination with the low molecular weight component (B) has a very high molecular weight (intrinsic viscosity [η]), the liquid ethylene / α-olefin copolymer By increasing the use ratio of the coalesced, it is possible to secure the processability (fluidity) required in the kneading process and the molding process using a roll, a Banbury mixer, or the like.

[0028] The ethylene / α-olefin / diene rubbers, which have been conventionally used and in which oils such as process oils, paraffin oils, and naphthenic oils are spread, have a limit in their processability improving effect. Further, in the case of an oil-extended ethylene / α-olefin / diene copolymer rubber having an intrinsic viscosity [η] of 3.5 dl / g or more, the workability is improved by keeping the product hardness within a predetermined range. Moreover, even if an attempt is made to reduce the viscosity at the time of processing by using a large amount of oil, it is not possible to obtain a vulcanized rubber molded article excellent in dynamic fatigue resistance due to the poor dispersibility of carbon and the like.

The liquid ethylene / α-olefin copolymer as described above can be produced, for example, by the method described in Japanese Examined Patent Publication No. 2-1163. That is, in the presence of a Ziegler catalyst, hydrogen is used as a molecular weight modifier, and ethylene is randomly copolymerized with an α-olefin having 3 to 20 carbon atoms to obtain a liquid ethylene / α-olefin copolymer. You can

Ethylene / α-olefin / diene-based rubber In the ethylene / α-olefin / diene-based rubber according to the present invention, the ethylene / α-olefin / diene copolymer rubber as the high molecular weight component (A) has a high molecular weight. Liquid ethylene as the low molecular weight component (B) is present in a proportion of 90 to 60% by weight, preferably 80 to 65% by weight, based on 100% by weight of the total amount of the component (A) and the low molecular weight component (B).
The α-olefin copolymer is present in an amount of 10 to 40% by weight, preferably 35 to 20% by weight, based on 100% by weight of the total amount of the above (A) and (B).

Ethylene according to the present invention comprising the high molecular weight component (A) and the low molecular weight component (B) as described above.
α-olefin / diene rubber has Mooney viscosity ML
_{1 + 4} (100 ° C) is 20 to 150, preferably 30 to 1
35, which is an ethylene / α-olefin / diene type
Low molecular weight rubber with molecular weight of 3,000 to 15,000
Region iodine value (IV ₁ ) and molecular weight 80,000-12
The ratio (IV ₁ / IV ₂ ) to the iodine value (IV ₂ ) in the high molecular weight region of 10,000 is 0.1 or less, preferably 0.
The ethylene / α-olefin / diene rubber having a Mooney viscosity ML _{1 + 4} (100 ° C.) and the above iodine value ratio (IV ₁ / IV ₂ ) within the above range is kneadable with a Banbury mixer or the like. Is excellent.

The ethylene / α-olefin / diene rubber of the present invention is prepared by mixing a solution or suspension of the high molecular weight component (A) with a solution or suspension of the low molecular weight component (B), and It can be obtained by collecting the substance. In addition, a high molecular weight component (A) or a low molecular weight component (B) is first obtained by polymerization, and other components are obtained by polymerization in the presence of the polymer. The ethylene / α-olefin / diene rubber of the invention can be obtained.

Rubber Composition for Heat-Resistant Anti-Vibration Rubber The rubber composition for heat-resistant anti-vibration rubber according to the present invention contains the above ethylene / α-olefin / diene rubber as a main component. In the present invention, in addition to the above ethylene / α-olefin / diene rubber, a softening agent, a filler, and a vulcanization agent which have been generally and widely used conventionally in the production of vulcanized rubber moldings made of ethylene / propylene rubber or the like. Compounding agents such as agents, vulcanization accelerators, vulcanization aids and the like can be used as long as the object of the present invention is not impaired. For example, when carbon black is used as the filler, the addition amount thereof is in the range of 5 to 90 parts by weight, preferably 40 to 85 parts by weight, based on 100 parts by weight of the above ethylene / α-olefin / diene rubber. .

The above-mentioned compounding agent and the ethylene of the present invention
The kneading with the α-olefin / diene rubber is carried out by using an ordinary rubber kneading machine such as Banbury mixer, open roll, kneader and the like.

In order to obtain a vulcanized rubber from the rubber composition for heat-resistant and vibration-proof rubber according to the present invention, an unvulcanized compounded rubber (heat-resistant and The rubber composition for vibrating rubber) may be once adjusted, and then this compounded rubber may be molded into an intended shape and then vulcanized.

When producing a vulcanized rubber, the above-mentioned ethylene
In addition to the α-olefin / diene rubber, the type and amount of the softening agent, and further the type and amount of the compound constituting the vulcanization system such as the vulcanizing agent, the vulcanization accelerator, and the vulcanization aid, and The process for producing the vulcanized rubber is appropriately selected.

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-based softeners such as tar and coal tar pitch; Fat oil-based softeners such as castor oil, linseed oil, rapeseed oil and coconut oil; tall oil; sub; waxes such as beeswax, carnauba wax and lanolin; ricinoleic acid , Palmitic acid, barium stearate,
Fatty acids and fatty acid salts such as calcium stearate and zinc laurate; synthetic polymer substances such as petroleum resin, atactic polypropylene and coumarone indene resin are used. Of these, petroleum-based softeners are preferably used, and process oils are particularly preferably used.

In producing a vulcanized rubber, as a vulcanizing agent,
The following sulfur compounds are used. Specific examples of the sulfur compounds include sulfur, sulfur chloride, sulfur dichloride, morpholine disulfide, alkylphenol disulfide, tetramethylthiuram disulfide,
Selenium dimethyldithiocarbamate or the like is used, and among them, sulfur is preferably used.

The above sulfur compound is the above ethylene / α
-For 100 parts by weight of olefin / diene rubber,
It is used in a proportion of 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight.

When a sulfur compound is used as a vulcanizing agent in producing a vulcanized rubber, it is preferable to use a vulcanization accelerator together. As the vulcanization accelerator, specifically, N-cyclohexyl-2-benzothiazole-sulfenamide, N-oxydiethylene-2-benzothiazole-sulfenamide, N, N-diisopropyl-2-benzothiazole- Sulfenamide, 2-mercaptobenzothiazole, 2- (2,4-
Dinitrophenyl) mercaptobenzothiazole, 2-
Thiazole compounds such as (2,6-diethyl-4-morpholinothio) benzothiazole and dibenzothiazyl-disulfide; diphenylguanidine, triphenylguanidine, diorsotolylguanidine, orthotriyl-by-
Guanidine compounds such as guanide and diphenylguanidine phthalate; acetaldehyde-aniline reaction products, butyraldehyde-aniline condensates, hexamethylenetetramine, acetaldehyde-ammonia reaction products and other aldehyde-amine or aldehyde-ammonia compounds; 2-mercaptoimidazoline And other imidazoline compounds; thiocarbanilide, diethylthiourea, dibutylthiourea, trimethylthiourea, diorsotolylthiourea, and other thiourea compounds; tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide , Thiuram compounds such as pentamethylene thiuram tetrasulfide; zinc dimethyldithiocarbamate, diet Zinc dithiocarbamate, di
-Dithioate compounds such as zinc n-butyldithiocarbamate, zinc ethylphenyldithiocarbamate, zinc butylphenyldithiocarbamate, sodium dimethyldithiocarbamate, selenium dimethyldithiocarbamate and tellurium diethyldithiocarbamate; xanthate compounds such as zinc dibutylxanthate. Compound; In addition, a compound such as zinc white is used.

The vulcanization accelerator is used in an amount of 0.1 parts by weight based on 100 parts by weight of the ethylene / α-olefin / diene rubber.
-20 parts by weight, preferably 0.2-10 parts by weight.

The unvulcanized compounded rubber is prepared by the following method. That is, using a mixer such as a Banbury mixer, the above ethylene / α-olefin / diene rubber and the softening agent are kneaded at a temperature of 80 to 170 ° C. for 3 to 10 minutes, and then rolls such as an open roll are used. , A vulcanizing agent and, if necessary, a vulcanization accelerator or a vulcanization aid are additionally mixed and kneaded at a roll temperature of 40 to 80 ° C. for 5 to 30 minutes, and then the kneaded product is extruded to form a ribbon or sheet. Prepare the rubber.

The compounded rubber thus prepared is molded into an intended shape by an extruder, a calender roll, or a press. Simultaneously with molding or by introducing the molded product into a vulcanization tank, it is heated at 150 to 270 ° C. Heat at a temperature for 1 to 30 minutes to obtain a vulcanized rubber. When performing such vulcanization, a mold may or may not be used.

[0044]

The rubber composition for heat and vibration resistant rubber according to the present invention comprises a high molecular weight component (A) consisting of a specific ethylene / α-olefin / diene copolymer rubber and a specific liquid ethylene / α-olefin. A bimodal molecular weight component containing a low molecular weight component (B) composed of a copolymer in a specific ratio
Mainly made of ethylene / α-olefin / diene rubbers that represent cloth
As an ingredient, this ethylene / α-olefin / diene-based rubber
Mooney viscosity ML _{1 + 4} (100 ℃)
Molecular weight of ren / α-olefin / diene rubber
Iodine value in low molecular weight region of 3,000 to 15,000 (I
V ₁ ) and a polymer having a molecular weight of 80,000 to 120,000
The ratio (IV ₁ / IV ₂ ) to the iodine value (IV ₂ ) of the region is
Since it is within the specified range, it has excellent heat resistance, anti-vibration properties and heat aging resistance, as well as processability (fluidity), shape retention during vulcanization molding, surface smoothness, mechanical strength characteristics, low compression set. It is possible to provide a vulcanized rubber molded article having excellent properties, abrasion resistance and dynamic fatigue resistance.

Since the rubber composition for heat-resistant and vibration-proof rubber according to the present invention has the above-mentioned effects, the heat-resistant and vibration-proof rubber, especially for automobile engine mounts, torsional dampers,
It can be used as a rubber composition such as a tension rod push, a steering rubber coupling, a center bearing support, a lower ring bush, a pump stopper and a muffler hanger.

Hereinafter, the present invention will be described with reference to Examples.
The present invention is not limited to these examples. The methods for evaluating the properties of the ethylene / α-olefin / diene rubbers and the vulcanized rubber molded products in Examples and Comparative Examples are as follows.

[1] Molecular weight distribution (Mw / Mn) Q value The molecular weight distribution (Mw / Mn) Q value was measured as follows in accordance with "Gel Permeation Chromatography", published by Takeuchi, Maruzen Co., Ltd. It was (1) Using standard polystyrene of known molecular weight (monodisperse polystyrene manufactured by Tosoh Corporation), molecular weight M and its GPC
(Gel Permeation Chromatog
Raphy) count, molecular weight M and elution volume E
A correlation diagram calibration curve with V (Elution Vlume) is created. The polystyrene concentration at this time is 0.02% by weight. (2) The GPC pattern of the sample is taken by the GPC measurement method, and the molecular weight M is known from the above (1). The sample preparation conditions and GPC measurement conditions in that case are as follows.

Sample preparation conditions (a) Samples are collected together with an o-dichlorobenzene solvent in an Erlenmeyer flask so that the concentration thereof will be 0.04% by weight. (B) Anti-aging agent 2,6-in the Erlenmeyer flask containing the sample
Di-tert-butyl-p-cresol is added at 0.1% by weight with respect to the polymer solution. (C) The Erlenmeyer flask is heated to 140 ° C. and stirred 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 pore filter having a diameter of 1 μm. (E) The filtrate is subjected to GPC analysis.

GPC measurement conditions (a) Device: Waters type 200 (b) Column: Tosoh Corp. S-type (Mix type) (c) Sample amount: 2 ml (d) Temperature: 135 ° C. (e) Flow rate: 1 ml / mm (he) Total theoretical plate number of column: 2 × 10 ⁴ to 4 × 10 ⁴ (measured value with acetone) [2] Tensile test JIS K 6301 (198)
9 years) No. 3 type dumbbell test piece was obtained, and the test piece was used in accordance with the method defined in the same JIS K 6301 Clause 3 to measure temperature 25 ° C. and pulling speed 500 mm /
Subjected to tensile test at a minute conditions, the 100% modulus (M _100), 200% modulus (M _200), 300%
The modulus (M ₃₀₀ ), the tensile stress at break T _B and the elongation at break E _B were measured.

[3] Hardness Test The hardness test was performed in accordance with JIS K 6301 (1989), and the spring hardness H _S (JIS A hardness) was measured.

[4] Compression set test The compression set test was conducted according to JIS K 6301 (1989).
Then, the compression set (%) was obtained.

[5] Low elongation stress test The low elongation stress test is performed according to JIS K 6301 (1989).
Then, the 25% elongation stress σ ₂₅ was obtained. The static shear elastic modulus G _s (kg / cm ² ) can be calculated by the following formula.

G _s = 1.639 × σ ₂₅ [6] Dynamic viscoelasticity test The dynamic viscoelasticity test was carried out using a rheometric viscoelasticity tester (model RDS-2) at a measurement temperature of 25 ° C. The dynamic shear elastic modulus (kg / cm ² ) was determined under the conditions of a frequency of 15 Hz and a strain rate of 1%. Further, the dynamic magnification (index of vehicle interior noise) and the loss tangent tan δ (index of riding comfort) were calculated by the following formulas.

G _s = G '+ ιG "(G _s : static shear modulus, real number G': dynamic shear modulus,
Imaginary number G ″: Dynamic loss elastic modulus) Dynamic magnification = G ′ / G _s tan δ = G ″ / G ′ [7] Heat aging resistance The heat aging resistance is as follows according to 6.5 of JIS K 6301 (1975). evaluated by the retention a _R of the stress at break of (T _B) and retention a _R of the elongation at break (E _B).

A dumbbell No. 1 type tensile test piece of JIS K 6301 was punched out from the longitudinal direction of the sheet, and the test piece was allowed to stand at 100 ° C., 120 ° C. and 150 ° C. for 70 hours, then returned to room temperature and 200 mm / min. A tensile test is performed at speed to measure stress at break (T Baged) and elongation at break (E Baged). On the other hand, the stress at break (T Borig) and the elongation at break (E Bori) of the sample before heat aging
g) is measured beforehand, and the stress retention at break and elongation retention at break are calculated.

A _R (T _B ) [%] = (T Baged / T Borig) × 100 A _R (E _B ) [%] = (E Baged / E Borig) × 100 First, in Examples and Comparative Examples. Two types of high molecular weight components and 5 types of low molecular weight components were prepared. The characteristics of these components are shown below.

[High molecular weight component-1 (EPT-1)] Ethylene content: 70 mol Non-conjugated diene: 5-ethylidene-2-norbornene (E
NB) Iodine number: 20 Intrinsic viscosity [η] measured in decalin at 135 ° C .: 2.7
dl / g molecular weight distribution (Mw / Mn) Q value: 2.8 [high molecular weight component-2 (EPT-2)] ethylene content: 70 mol% non-conjugated diene: 5-ethylidene-2-norbornene (E
NB) Iodine value: 20 Intrinsic viscosity [η] measured in decalin at 135 ° C .: 4.0
dl / g Molecular weight distribution (Mw / Mn) Q value: 3.2 [Low molecular weight component-1 (EP-1)] Ethylene content: 75.0 mol% Intrinsic viscosity [η]: 0 measured at 135 ° C decalin .2
4 dl / g Molecular weight distribution (Mw / Mn) Q value: 2.2 [Low molecular weight component-2 (EP-2)] Ethylene content: 60 mol% Intrinsic viscosity [η] measured in decalin at 135 ° C: 1.0
dl / g Molecular weight distribution (Mw / Mn) Q value: 2.1 [Low molecular weight component-3 (EP-3)] Ethylene content: 60 mol% Intrinsic viscosity [η] measured in 135 ° C. decalin: 1.2
dl / g molecular weight distribution (Mw / Mn) Q value: 2.2 [low molecular weight component-4 (EPT-3)] ethylene content: 70 mol% non-conjugated diene: 5-ethylidene-2-norbornene (E
NB) Iodine number: 13 Intrinsic viscosity [η] measured in 135 ° C decalin: 0.2
5 dl / g Molecular weight distribution (Mw / Mn) Q value: 2.4 [Low molecular weight component-5 (EP-4)] Ethylene content: 68 mol% Intrinsic viscosity [η]: 0.3 measured in 135 ° C decalin
0 dl / g molecular weight distribution (Mw / Mn) Q value: 2.2

[0058]

Example 1 High molecular weight component-1 (EPT-1) 10
0 parts by weight, 30 parts by weight of the above low molecular weight component-1 (EP-1), and paraffinic process oil [Idemitsu Kosan Co., Ltd.
Made by Diana Process Oil PW-380] and melt-kneaded with 30 parts by weight, and Mooney viscosity ML _{1 + 4} after oil extension
(100 ° C) 42, IV ₁ / IV ₂ 0 ethylene
A propylene / diene rubber was obtained.

100 parts by weight of the obtained ethylene / propylene / diene rubber, 5 parts by weight of Zinc Hua No. 1, 1 part by weight of stearic acid, and FEF carbon black [Asahi Carbon Co., Ltd., Asahi 60HG] 60 parts by weight The parts were kneaded with a Banbury mixer [made by Kobe Steel, Ltd.] having a capacity of 4.3 liters.

The kneaded material obtained in this manner was mixed with about 5
After cooling to 0 ° C., 0.5 parts by weight of sulfur, 3.0 parts by weight of NOXCELLER M [MBT manufactured by Ouchi Shinko Chemical Industry Co., Ltd., vulcanization accelerator], NOXCELLER BZ [Ouchi Shinsei Chemical Co., Ltd.] were added to the kneaded product. ZnBDC manufactured by Kogyo Co., Ltd., vulcanization accelerator] 1.5 parts by weight and NOXCELLER TT [TMTD manufactured by Ouchi Shinko Chemical Co., Ltd.,
Vulcanization accelerator] After adding 0.75 parts by weight and kneading with an 8-inch roll (front and rear roll temperature: 55 ° C.), a vulcanized sheet having a thickness of 2 mm is dispensed into a sheet and pressed at 150 ° C. for 18 minutes. And a physical property test was performed on this vulcanized sheet.

Further, the above press conditions were set to 150 ° C. for 20 minutes to obtain a thick vulcanized rubber molded product for compression set test,
A compression set test was conducted on this thick vulcanized rubber molded product.

The results are shown in Tables 1 and 2.

[0063]

Comparative Example 1 In Example 1, the low molecular weight component-1 (E
Example 1 except that the compounding amounts of P-1) and the paraffinic process oil were 0 parts by weight and 60 parts by weight, respectively.
It carried out similarly to.

The obtained ethylene / propylene / diene rubber had a Mooney viscosity ML _{1 + 4} (100
C.) was 42 and IV ₁ / IV ₂ was 18. The results are shown in Tables 1 and 2.

[0065]

Example 2 In Example 1, the low molecular weight component-1 (E
Example 1 except that the compounding amount of P-1) was 60 parts by weight.
It carried out similarly to.

The obtained ethylene / propylene / diene rubber had a Mooney viscosity ML _{1 + 4} (100
C.) was 41 and IV ₁ / IV ₂ was 0. The results are shown in Tables 1 and 2.

[0067]

Comparative Example 2 In Example 2, the low molecular weight component-1 (E
It carried out like Example 2 except having used low molecular weight ingredient-2 (EP-2) instead of P-1).

The obtained ethylene / propylene / diene rubber had a Mooney viscosity ML _{1 + 4} (100
C.) was 50 and IV ₁ / IV ₂ was 0. The results are shown in Tables 1 and 2.

[0069]

Comparative Example 3 In Example 2, the low molecular weight component-1 (E
It carried out like Example 2 except having used low molecular weight ingredient-3 (EP-3) instead of P-1).

The obtained ethylene / propylene / diene rubber had a Mooney viscosity ML _{1 + 4} (100
C.) was 52 and IV ₁ / IV ₂ was 0. The results are shown in Tables 1 and 2.

[0071]

Comparative Example 4 In Example 2, the low molecular weight component-1 (E
Instead of P-1), low molecular weight component-4 (EPT-3)
The same procedure as in Example 2 was carried out except that was used.

The obtained ethylene / propylene / diene rubber had a Mooney viscosity ML _{1 + 4} (100
° C.) is 42, IV ₁ / IV ₂ was 0.65. The results are shown in Tables 1 and 2.

[0073]

Comparative Example 5 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 stearic acid 0. 5 parts by weight, Zinc Hua No. 1 5 parts by weight, HAF carbon [Tokai Carbon Co., Ltd., Seast 3] 40 parts by weight, paraffin type process oil [Kyodo Oil Co., Ltd., Sonic Process Oil P-30
0] 20 parts by weight were kneaded with a 4.3 Banbury mixer [made by Kobe Steel, Ltd.].

The kneaded product thus obtained was mixed with sulfur 1
Parts by weight, vulcanization accelerator [Ouchi Shinko Chemical Industry Co., Ltd., Nox Cellar CZ] 1.5 parts by weight, and antioxidant [Ouchi Shinko Chemical Industry Co., Ltd., Nocrac AD] 3 parts by weight. After kneading with a roll, it is dispensed into sheet form and 150 ℃
Was pressed for 30 minutes to obtain a vulcanized sheet having a thickness of 2 mm, and the vulcanized sheet was evaluated.

Further, the above press conditions were changed to 150 ° C. for 13 minutes to obtain a thick vulcanized rubber molded product for compression set test,
A compression set test was conducted on this thick vulcanized rubber molded product.

The results are shown in Tables 1 and 2.

[0077]

Example 3 In Example 2, the low molecular weight component-1 (E
It carried out like Example 2 except having used low molecular weight ingredient -5 (EP-4) instead of P-1).

The obtained ethylene / propylene / diene rubber had a Mooney viscosity ML _{1 + 4} (100
C.) was 42 and IV ₁ / IV ₂ was 0. The results are shown in Tables 1 and 2.

[0079]

[Table 1] FIG. 1 shows the relationship between the dynamic magnification and tan δ of the vulcanized rubbers of Examples 1 to 3 and Comparative Examples 1 to 5. As is clear from FIG. 1, an ethylene / α-olefin composed of a high molecular weight component-1 having an intrinsic viscosity [η] of 2.7 dl / g and a low molecular weight component-1 having an intrinsic viscosity of [η] of 0.24 dl / g. In Example 1 using the diene-based rubber, a vulcanized rubber having substantially the same dynamic magnification as in Comparative Example 1 but having a large tan δ vibration-damping property was obtained. Further, in Example 2, in which the ethylene / α-olefin / diene rubber was blended with a large amount of the low molecular weight component-1, the vibration isolation with a larger tan δ was obtained as compared with Example 1. A vulcanized rubber having characteristics is obtained. As described above, in the present invention, the vibration damping property of the rubber can be controlled by the blending amount of the low molecular weight component. Regarding the above-mentioned vibration-proof property, the molecular weight of the low-molecular-weight component is a decisive factor, and when a low-molecular-weight component having an intrinsic viscosity [η] as an index of the molecular weight of more than 0.4 dl / g is used, control of the above-mentioned vibration-proof property becomes unsatisfactory. This is possible, and this is made clear by Comparative Examples 2 and 3.

[0080]

[Table 2]

In Table 2, Examples 1 to 3 and Comparative Example 5
As is clear from comparison with vulcanized rubber using the rubber composition for heat-resistant and vibration-proof rubber of the present invention, compared with NR-SBR vulcanized rubber currently used as a polymer for vibration-proof rubber materials. And the heat aging resistance is remarkably excellent, 120 ° C x 7
2 hrs. Under aging conditions of about 2 times better.
This means that the vulcanized rubber using the rubber composition for heat-resistant and vibration-proof rubber according to the present invention has a smaller rate of change in the vibration-damping property than the NR-SBR-based vulcanized rubber. It has excellent heat stability.

As is clear from the comparison between Comparative Example 4 in Table 2 and Examples 1 to 3, the intrinsic viscosity [η] of the low molecular weight component is shown.
Is in the range of 0.2 to 0.4 dl / g, but when the diene component is copolymerized in the low molecular weight component, only a vulcanized rubber having a particularly deteriorated compression set is obtained. Absent. Therefore, in the present invention, the rubber composition using the above-mentioned low-molecular weight component instead of the low-molecular weight component of the present invention cannot be used for a vibration-proof rubber for supporting an engine, and The vibration damping characteristics as seen in the examples are not sufficiently exhibited.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the dynamic magnification and tan δ of the vulcanized rubbers of Examples 1 to 3 and Comparative Examples 1 to 5.

Claims (1)

(57) [Claims] 1. A molecular weight distribution (Mw / Mw) determined by GPC measurement, comprising ethylene, an α-olefin having 3 to 20 carbon atoms and a non-conjugated diene, and having an ethylene content of 60 to 73 mol%. Mn) Q value is less than 4 and 1
Intrinsic viscosity [η] measured in decalin at 35 ° C is 2.7-
High molecular weight component (A) consisting of ethylene / α-olefin / diene copolymer rubber having an iodine value of 10 to 40, 5.0 dl / g: 90 to 60% by weight, and ethylene and 3 to 3 carbon atoms. 20 α-olefin, and has an ethylene content of 50 to 78 mol%,
The intrinsic viscosity [η] measured in decalin at 135 ° C is 0.2.
Low molecular weight component (B) consisting of liquid ethylene / α-olefin copolymer of about 0.4 dl / g: 10 to 40% by weight of ethylene showing a bimodal molecular weight distribution
Mooney containing ethylene-α -olefin / diene rubber as a main component and α-olefin / diene rubber as the main component
Viscosity ML _{1 + 4} (100 ° C) is within the range of 20-150.
In the ethylene / α-olefin / diene rubber
With a low molecular weight range of 3,000 to 15,000
Elementary value (IV ₁ ) and molecular weight 80,000 to 120,000
With the iodine value (IV ₂ ) of the polymer region of (IV ₁ / I
V ₂ ) is 0.1 or less, a rubber composition for a heat and vibration resistant rubber.