JP2000220689A - Engine mount insulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain vibrationproofing properties, durability, low temperature flexibility and heat resistance properties, to be required for an engine mount insulator on a high level. SOLUTION: Hundred part of EPDM, by weight wherein ethylene/propylene is 60/40 to 73/27, a molecular weight distribution Q value is less than 4, its ultimate viscosity (η) is 3.0 to 5.0 dl/g, its iodine value is 10 to 40, and its non- conjugated diene is 5-ethylidene-2-norbornane, is kneaded with 1 to 70 parts of liquid shaped ethylene.propylene copolymer wherein ethylene/propylene is 50/50 to 78/22, its ultimate viscosity (η) is 0.2 to 0.4 dl/g, and 0.1 2.0 parts of sulfur, by weight, and with 30 to 90 parts of carbon-black, by weight so as to be formed into a fluid sealing type rubber elastic body 3. The frequency characteristics of the aforesaid rubber elastic body 3 shall satisfy |(Kdmin-10)-Kd|<=20 (Hz).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine mount insulator in which a mass member is connected to a vibrating body such as a power plant of an automobile through a rubber elastic body for the purpose of damping the vibration. The present invention relates to an engine mount insulator with improved vibration damping, durability, low-temperature flexibility, and heat resistance of an elastic body.

[0002]

2. Description of the Related Art An engine mount insulator for an automobile needs a function of supporting most of the load on the engine and a torque reaction force generated by the engine, and also needs good soundproofing and vibrationproofing performance. Therefore, usually, the engine mount insulator includes:
Natural rubber having a moderate vibration damping performance and excellent fatigue resistance is used as a main component.

[0003] Instead of the natural rubber, butadiene rubber,
Styrene butadiene rubber, chloroprene rubber, butyl rubber and the like may be used alone, but in many cases, butadiene rubber, styrene butadiene rubber, chloroprene rubber, butyl rubber and the like are blended with the natural rubber.

[0004]

In recent automobiles, there is a problem that the heat environment in the engine mount insulator is deteriorated because the heat radiation space in the engine room is reduced and the output of the engine is increased. In this problem, in the case of diene rubber represented by natural rubber, the limit has already been reached.

[0005] To solve the above problem, as shown in JP-A-6-1891 and JP-A-10-89409, etc.
Anti-vibration rubbers containing ethylene propylene diene rubber (hereinafter referred to as EPDM) as a main component, which has been considered difficult to commercialize in the prior art, have begun to be gradually used. But,
The engine mount insulator containing EPDM as a main component exhibits excellent durability and heat resistance when it is made of a specific rubber composition, but is inferior in dynamic magnification to natural rubber-based anti-vibration rubber. was there.

To solve this problem, for example, Japanese Patent Laid-Open
As shown in -239289, a method of reducing the dynamic magnification by using a silane-treated silica as the rubber composition of the EPDM is known, but it has not been able to obtain a sufficient effect. Due to the problems described above, the emergence of an engine mount insulator having excellent heat resistance, a sufficiently low dynamic magnification, and excellent vibration damping properties has been strongly desired.

[0007] The present invention has been made based on the above-mentioned problems, and has improved the composition of a rubber elastic body constituting an engine mount insulator, and has a strength and durability equal to or greater than that of a case where a natural rubber material is used. It is an object of the present invention to provide an engine mount insulator having both heat resistance and low-temperature flexibility while improving heat resistance and vibration isolation.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a method for producing ethylene-propylene-non-conjugated diene having a specific ethylene content, iodine value, melt flow index and viscosity. In an engine mount insulator using a rubber composition containing a specific amount of carbon black and sulfur in a polymer rubber as a rubber elastic support of a vibration isolator, the rubber elastic support has the following (a) to (d). ) As a main component.

(A) It is composed of ethylene, propylene and a non-conjugated diene, and the molar ratio of ethylene to propylene is 60/40 to 73/27, and the value Q of the molecular weight distribution measured by GPC is less than 4, 135 The intrinsic viscosity (η) measured in decalin is 3.0 to 5.0 dl / g, the iodine value is 10 to 40, and the non-conjugated diene is 5
-100 parts by weight of ethylene / propylene / non-conjugated diene copolymer rubber which is ethylidene-2-norbornene.

(B) consisting of ethylene and propylene,
The molar ratio of ethylene to propylene is 50/50 to 7;
1 to 70 parts by weight of a liquid ethylene / propylene copolymer having an intrinsic viscosity (η) of 0.2 to 0.4 dl / g as measured in decalin at 135 ° C. at 8/22.

(C) 0.1 to 2 parts by weight of sulfur.

(D) 30 to 90 parts by weight of carbon black.

According to a second aspect of the present invention, in the first aspect, a fluid-filled anti-vibration support is formed by using a rubber elastic support made of the rubber composition, and the anti-vibration support includes a first fluid chamber and a first fluid chamber. 2
This is a structure for obtaining a resonance phenomenon of an incompressible fluid in an orifice communicating with a fluid chamber, and has a frequency characteristic of a fluid-filled vibration-proof support that satisfies the following equation.

| (Kd _min −10) −kd | ≦ 20 (Hz) (1) (kd _min is the frequency of the minimum value of the dynamic spring constant, kd is the frequency of the vibration to be processed) The ethylene of the above (a) The propylene / non-conjugated diene copolymer rubber has a molar ratio of ethylene to propylene (ethylene / propylene) of 60/40 to 73/27. When the molar ratio is less than 60/40, the durability (strength) of the vulcanized rubber of the obtained rubber composition tends to decrease.
On the other hand, when the molar ratio exceeds 73/27, the vulcanized rubber of the obtained rubber composition has low flexibility at low temperatures,
At such low temperatures, the spring constant of the engine mount insulator tends to change significantly. In addition, as the non-conjugated diene, specifically, 5-ethylidene-2-
Norbornene is used.

The ethylene / propylene / non-conjugated diene copolymer rubber of (a) has an iodine value of 10 to 40, preferably 15 to 40, which is an index of the non-conjugated diene content.
20. When the iodine value is less than 10, the vulcanization rate of the obtained rubber composition tends to be low. on the other hand,
When the iodine value exceeds 40, the vulcanized rubber of the obtained rubber composition tends to have reduced heat resistance.

Further, the ethylene / propylene / non-conjugated diene copolymer rubber (a) has a molecular weight distribution (Mw / Mn) value Q determined by GPC measurement of less than 4,
Preferably it is 3 or less. By using a high-molecular-weight ethylene / propylene / non-conjugated diene copolymer rubber having such a molecular weight distribution, it becomes possible to obtain a vulcanized rubber excellent in mechanical strength characteristics and dynamic fatigue resistance.

Further, the ethylene / propylene / non-conjugated diene copolymer rubber (a) has an intrinsic viscosity (η) of 3.0 to 5.0 (dl) measured at 135 ° C. in decalin.
/ G), preferably 3.5 to 4.5 (dl / g). When the intrinsic viscosity (η) is less than 3.0, the durability tends to decrease. On the other hand, when the intrinsic viscosity (η) exceeds 5.0 (dl / g), the productivity of polymer synthesis tends to decrease. When an ethylene / propylene / non-conjugated diene copolymer rubber having an intrinsic viscosity (η) within the above range is used, a rubber composition having excellent dynamic fatigue resistance can be obtained.

The liquid ethylene-propylene copolymer (b) does not contain a diene component. In addition, (b)
The liquid ethylene-propylene copolymer is a random copolymer of ethylene and propylene.

In the present invention, the high molecular weight ethylene / propylene / non-conjugated diene copolymer rubber (a) is provided with the effects of improving heat resistance, mechanical strength characteristics, dynamic fatigue resistance and the like. The low molecular weight liquid ethylene / propylene copolymer (b) was designed so as to have effects such as heat aging resistance and processability (fluidity).

However, it is merely bimodal, that is, it shows a molecular weight distribution having two modes,
In the ethylene / propylene / non-conjugated diene copolymer rubber composed of a high molecular weight component and a low molecular weight component, the ratio of the effect of improving the physical properties such as heat resistance, mechanical strength characteristics and dynamic fatigue resistance by the high molecular weight component is low. Since the proportion of the effect of improving the workability (flowability) by the molecular weight component is in a so-called tug-of-war relationship, even if the workability is improved by increasing the number of low molecular weight components, the physical properties such as fatigue resistance are not improved. Dramatically improved vulcanized rubber cannot be provided.

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

The liquid ethylene / propylene copolymer used in the present invention has a molar ratio of ethylene to propylene of 5
0/50 to 78/22 mol%, preferably 50/50 to
It is in the range of 70/30. The liquid ethylene / propylene copolymer having a molar ratio in the above range has good thermal stability, and thus has a high molecular weight ethylene / propylene copolymer as described above.
There is no reduction in weight during the kneading operation with the propylene / non-conjugated diene copolymer rubber, and no carbonization at the time of molding and contamination of the molded product.

The liquid ethylene / propylene copolymer has an intrinsic viscosity (η) of 0.2 to 0.4 (dl / g) measured at 135 ° C. in decalin. If the intrinsic viscosity (η) is not in this range, the rubber composition tends to have low processability (kneading properties).

That is, since the liquid ethylene / propylene copolymer is not crosslinked as a polymer in the vulcanized rubber, it acts as a softener, and is used for general ethylene / propylene / non-conjugated diene copolymer rubber. Processability against paraffinic process oil, which is a softener for
Excellent in mechanical strength characteristics and heat aging resistance.

In the rubber composition used in the present invention, 1 to 70 parts by weight of a liquid ethylene / propylene copolymer is added to 100 parts by weight of a high molecular weight ethylene / propylene / non-conjugated diene copolymer rubber. . When the amount is less than 1 part by weight, the effect of improving the workability and the like is small. When the amount exceeds 70 parts by weight, the tan δ of the vulcanized rubber of the rubber composition becomes unnecessarily large, and the dynamic magnification of the engine mount insulator deteriorates.

When mixing the ethylene / propylene / non-conjugated diene copolymer rubber with the liquid ethylene / propylene / copolymer, a solution or suspension of the ethylene / propylene / non-conjugated diene copolymer and the liquid ethylene / propylene / non-conjugated diene copolymer are mixed. -It can be obtained by mixing a solution or suspension of the propylene copolymer and then collecting a solid. Also, first, one of ethylene / propylene / non-conjugated diene copolymer rubber or liquid ethylene / propylene copolymer is obtained by polymerization, and further the other components are obtained by polymerization in the presence of the polymer, so-called multistage. It can also be obtained by a polymerization method. Alternatively, the ethylene / propylene / non-conjugated diene copolymer rubber and the ethylene / propylene copolymer may be mixed by a kneader such as a Banbury mixer or a roll.

The sulfur is used as a vulcanizing agent. Sulfur is used in an amount of 0.1 to 2 parts by weight based on 100 parts by weight of the ethylene / propylene / non-conjugated diene copolymer rubber composition.

The type of the carbon black is not particularly limited as long as it is carbon black for rubber.
Carbon black such as AF, MAF, FEF, and GPF is preferred.

In the rubber-like elastic support for an engine mount insulator according to the present invention, carbon black is used in an amount of 30 to 90 parts by weight based on 100 parts by weight of the ethylene / propylene / non-conjugated diene copolymer rubber. Used.

When the amount of carbon black is less than 30 parts by weight, the obtained vulcanized rubber tends to have reduced strength. On the other hand, if the compounding amount of carbon black exceeds 90 parts by weight, the resulting rubber composition tends to have low processability and poor dispersion of carbon black.

A rubber-like elastic support for an engine mount insulator of the present invention is provided with a vulcanized rubber molded body made of ethylene propylene rubber or the like in addition to the ethylene / propylene / non-conjugated diene copolymer rubber, sulfur and carbon black. In the production, compounding materials that have been widely used in the past, for example, vulcanization accelerators, vulcanization aids, softeners, and the like can be used as long as the object of the present invention is not impaired.

As described above, in the present invention, in order to improve the heat resistance of the engine mount insulator, a specific rubber elastic material containing a specific ethylene / propylene / non-conjugated diene copolymer as a main component is used. In order to achieve both the heat resistance and the dynamic characteristics of the engine mount insulator, a fluid-filled vibration-proof support is formed by using a molded product made of the rubber composition of the present invention. The vibration support has a structure for obtaining a resonance phenomenon of the incompressible fluid in the orifice communicating the first fluid chamber and the second fluid chamber, and the frequency characteristic of the fluid-filled vibration-proof support that satisfies the above expression (1). , It can be realized for the first time.

For example, even when the rubber composition is used, a satisfactory performance in dynamic characteristics cannot be obtained with a normal rubber-only engine mount insulator. Even in the case of a fluid-enclosed vibration-proof support, sufficiently satisfactory heat resistance cannot be obtained unless the rubber composition is used. Further, when the above expression (1) is not satisfied,
Since the frequency at which the minimum value of the dynamic spring constant of the resonance phenomenon obtained by the fluid-filled type vibration isolation support is shifted from the frequency range of the target sound vibration phenomenon, sufficient dynamic characteristics cannot be obtained.

Therefore, by satisfying all the requirements in the present invention as described above, an engine mount insulator having sufficient heat resistance and excellent dynamic characteristics can be obtained for the first time.

[0035]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a typical embodiment of an engine mount insulator (fluid-filled type vibration damping device) of the present invention. In FIG. 1, a mounting bracket 1 on a power unit side including an engine and a mounting bracket 2 on a vehicle body are arranged to face each other, and both mounting brackets 1 and 2 are connected by a rubber elastic body (fluid-sealed type) 3. A diaphragm 5 forming a fluid chamber 4 with the rubber elastic body 3 on one mounting fitting 2 side;
A partition member 8 which separates the interior of the first fluid chamber (main liquid chamber) 6 on the rubber elastic body 3 side and a second fluid chamber (sub liquid chamber) 7 on the diaphragm 5 side is attached. And, the partition member 8 is provided with an orifice 9 for communicating the first fluid chamber 6 and the second fluid chamber 7.

By configuring the engine mount insulator as shown in FIG. 1, the first fluid chamber 6 and the second
The fluid characteristic 7 is communicated with the orifice 9 to obtain a frequency characteristic in which the minimum value of the dynamic spring constant satisfies the expression (1) based on the dynamic damper effect when the incompressible fluid passes through the orifice 11. Can be.

Next, specific examples of the rubber composition forming the rubber elastic body 3 will be described as Examples (Examples 1 to 3).

First, in Example 1, 10 parts by weight of a liquid ethylene propylene copolymer and 70 parts by weight of N550 carbon black were added to 100 parts by weight of EPDM and kneaded to obtain a kneaded product. After the rubber elastic body 3 was molded and joined to the mounting brackets 1 and 2, a sample of a fluid-filled vibration isolator as shown in FIG. 1 was produced. In addition,
In the EPDM of the sample of Example 1, the molar ratio of ethylene to propylene (ethylene / propylene) was 7
1/29, iodine value is 19.5, intrinsic viscosity (η) is 3.
8 dl / g, molecular weight distribution Q value was 2.8. In the liquid ethylene-propylene copolymer, ethylene /
Propylene 68/32, intrinsic viscosity (η) 0.3 dl
/ G.

In Example 2, 20 parts by weight of a liquid ethylene propylene copolymer was added to 100 parts by weight of EPDM,
65 parts by weight of N550 carbon black were added and kneaded to obtain a kneaded product. Using this kneaded product, a sample of a fluid-sealed vibration isolator was prepared in the same manner as in Example 1. In the EPDM of the sample of Example 2, ethylene / propylene was 68/32, iodine value was 15, intrinsic viscosity (η)
Was 4.2 dl / g, and the molecular weight distribution Q value was 2.8. In the liquid ethylene-propylene copolymer, ethylene / propylene is 68/32 and intrinsic viscosity (η) is 0.1.
It was 3 dl / g.

In Example 3, 25 parts by weight of a liquid ethylene propylene copolymer was added to 100 parts by weight of EPDM,
60 parts by weight of N550 carbon black was added and kneaded to obtain a kneaded material, and a sample of a fluid-sealed type vibration damping device was prepared in the same manner as in Example 1 using the kneaded material. In the EPDM of the sample of Example 3, the ethylene / propylene ratio was 72/28, the iodine value was 13, and the intrinsic viscosity (η).
Was 3.8 dl / g, and the molecular weight distribution Q value was 2.8. In the liquid ethylene-propylene copolymer, ethylene / propylene is 68/32 and intrinsic viscosity (η) is 0.1.
It was 3 dl / g.

The samples of Examples 1 to 3 contained 5 parts by weight of zinc oxide, 1 part by weight of stearic acid, and a thiazole vulcanization accelerator (hereinafter referred to as vulcanization accelerator) in addition to the above components. 3 parts by weight of an agent B), 1 part by weight of a dithiocarbamate-based vulcanization accelerator (hereinafter, referred to as a vulcanization accelerator C), and a thiuram-based vulcanization accelerator (hereinafter, referred to as a vulcanization accelerator D). 1.5 parts by weight and a vulcanizing agent (sulfur) 1 part by weight.

Table 1 below shows the components of the samples of Examples 1 to 3, and the workability of the kneaded material in each of the samples was evaluated in three stages of △, Δ, and × (○: excellent workability). ,
△: good workability, ×: poor workability), the results of product durability tests (without heat aging treatment and with heat aging treatment), and Frequency characteristics (| (kd _min -10) -kd
│), product dynamic magnification (kd100 / ks), and product low-temperature properties (−30 ° Cks / 23 ° Cks) are shown.

In the above product durability test, a load of 90 kg ± 180 kg was applied in the P direction as shown in FIG.
The heat aging treatment in the product durability test was performed at 140 ° C. × 72 hours at an ambient temperature of 70 ° C. The measurement of the product dynamic magnification is performed in the following manner.
The interval was ± 1 mm, the load was 90 kg in the P direction, and the amplitude was ± 0.05 mm at a dynamic spring constant of 150 Hz.
The measurement of the product low-temperature property was performed by leaving the sample to be measured in a low-temperature static spring constant in a constant temperature bath at -30 ° C. for 3 hours, immediately removing the sample, and performing the measurement at room temperature.

[0044]

[Table 1]

As shown in Table 1 above, the samples of Examples 1 to 3 were each prepared within the scope of the claims and had excellent workability, and the product durability test (target value; 500,000 times or more, when heat aging treatment is performed at 140 ° C. for 72 hours, 300,000 times or more), product dynamic magnification (target value: 3.0 or less), product low temperature property (target value: 3.0 or less) )
At each of the target values, and |
(Kd _min −10) −kd | was 20 or less (within the scope of the claims), and good results were obtained. In addition, it has been found that a sufficient dynamic spring constant reduction effect can be obtained in the target frequency region in order to satisfy Expression (1) (described later with reference to FIG. 2).

Next, for comparison with Examples 1 to 3, specific examples of the rubber composition formed by the prior art will be described as Comparative Examples (Comparative Examples 1 to 8).

First, in Comparative Example 1, 70 parts by weight of NR, 30 parts by weight of SBR, N5
Using a kneaded material obtained by kneading using 50 parts by weight of 50 carbon black, a sample of a vibration isolator made of rubber alone was prepared without using a fluid.

In Comparative Example 2, ethylene / propylene was 6
8/32, iodine value is 12, intrinsic viscosity is 2.6 dl /
g, EPDM having a molecular weight distribution Q value of 2.7,
70 parts by weight of N550 carbon black was added to 100 parts by weight of the PDM and kneaded to obtain a kneaded product. Using the kneaded product, a sample of a vibration isolator consisting of a single rubber was prepared in the same manner as in Comparative Example 1.

In Comparative Example 3, ethylene / propylene was 7
1/29, iodine value 19.5, intrinsic viscosity 3.8 dl
/ G, EPDM having a molecular weight distribution Q value of 3.0, 70 parts by weight of N550 carbon black was added to 100 parts by weight of the EPDM and kneaded to obtain a kneaded product. In the same manner as in the above, a sample of a vibration isolator made of rubber alone was produced.

In Comparative Example 4, 10 parts by weight of the liquid ethylene propylene copolymer was added to 100 parts by weight of EPDM,
70 parts by weight of N550 carbon black were added and kneaded to obtain a kneaded product. Using this kneaded product, a sample of a vibration isolator consisting of a single rubber was prepared in the same manner as in Comparative Example 1. In the EPDM of the sample of Comparative Example 4, ethylene /
Propylene was 71/29, iodine value was 19.5, intrinsic viscosity (η) was 3.8 dl / g, and molecular weight distribution Q value was 3.5. In the liquid ethylene-propylene copolymer, ethylene / propylene was 68/32 and intrinsic viscosity (η) was 0.3 dl / g.

In Comparative Example 5, 10 parts by weight of the liquid ethylene propylene copolymer was added to 100 parts by weight of EPDM,
70 parts by weight of N550 carbon black were added and kneaded to obtain a kneaded material. Using this kneaded material, a sample of a fluid-filled type vibration damping device was prepared in the same manner as in Example 1. In the EPDM of the sample of Comparative Example 5, ethylene / propylene was 71/29, iodine value was 19.5, intrinsic viscosity (η) was 3.8 dl / g, and molecular weight distribution Q value was 2.8. In the liquid ethylene-propylene copolymer, ethylene / propylene was 68/32 and intrinsic viscosity (η) was 0.3 dl / g.

In Comparative Example 6, 70 parts by weight of NR, 30 parts by weight of SBR, N550
A kneaded material obtained by kneading using 70 parts by weight of carbon black was used to prepare a sample of a fluid-filled type vibration damping device in the same manner as in Example 1.

In Comparative Example 7, 10 parts by weight of a liquid ethylene propylene copolymer was added to 100 parts by weight of EPDM, 30 parts by weight of N550 carbon black, 40 parts by weight of silane-treated silica, and 3 parts by weight of a silane coupling agent. A kneaded product was obtained by adding and kneading a part of the mixture, and a sample of a vibration isolator made of a simple rubber was prepared using this kneaded product in the same manner as in Comparative Example 1. The EPD in the sample of Comparative Example 7 was used.
In M, ethylene / propylene was 71/29, iodine value was 19.5, intrinsic viscosity (η) was 3.8 dl / g, and molecular weight distribution Q value was 3.5. In a liquid ethylene-propylene copolymer, ethylene / propylene is 6%.
8/32, intrinsic viscosity (η) was 0.3 dl / g.

In Comparative Example 8, 10 parts by weight of a liquid ethylene propylene copolymer was added to 100 parts by weight of EPDM, 70 parts by weight of a silane-treated silica, and 3 parts by weight of a silane coupling agent were added and kneaded to obtain a kneaded product. Using the kneaded material, a sample of a vibration isolator made of a single rubber was produced in the same manner as in Comparative Example 1. In the EPDM of the sample of Comparative Example 8, ethylene / propylene was 71%.
/ 29, iodine value is 19.5, intrinsic viscosity (η) is 3.8
dl / g, and the molecular weight distribution Q value was 3.5. In the liquid ethylene-propylene copolymer, ethylene / propylene is 68/32 and intrinsic viscosity (η) is 0.3 dl /.
g.

The samples of Comparative Examples 1 and 6 contained, in addition to the above components, 5 parts by weight of zinc oxide, 1 part by weight of stearic acid, 3 parts by weight of an antioxidant, and a sulfenamide-based compound. 1 part by weight of a vulcanization accelerator and 2 parts by weight of a vulcanizing agent (sulfur) were blended. In each of Comparative Examples 2 to 5, 7, and 8, 5 parts by weight of zinc oxide, 1 part by weight of stearic acid, 3 parts by weight of vulcanization accelerator B, and 3 parts by weight of vulcanization accelerator C1 were used. , 1.5 parts by weight of vulcanization accelerator D and 1 part of vulcanizing agent (sulfur)
Parts by weight were blended.

Table 2 below shows the same as in Examples 1 to 3 above.
In addition to showing the components of each sample of Comparative Examples 1 to 8, the processability of the kneaded material in each sample was evaluated in three stages of の, Δ, and X (○: excellent processability, Δ: good processability). is there,
×; poor workability), a product durability test, and a frequency characteristic (│ (kd
_min- 10) -kd |), product dynamic magnification (kd100 / k
s) shows the results obtained by measuring the low temperature properties of the product (−30 ° Cks / 23 ° Cks).

[0057]

[Table 2]

As shown in Table 2, in the case of the sample of Comparative Example 1, since a natural rubber-based material was used, a satisfactory result was not obtained in durability after the heat aging treatment. Further, in the frequency characteristics, a phenomenon was observed in which the spring constant was increased with an increase in the characteristic frequency of the vibration isolator (anti-vibration rubber) made of rubber alone (described later with reference to FIG. 2). .

In the case of the sample of Comparative Example 2, the workability was poor, and there was a possibility that the variation in durability was large.
The durability was deteriorated due to the low intrinsic viscosity of PDM. In the case of the sample of Comparative Example 3, since the intrinsic viscosity of EPDM is high and the amount of carbon black is as high as 70 parts by weight,
Since the rubber could not be kneaded at all and the sample could not be vulcanized, each measurement could not be performed. Comparative Example 4
In the case of the sample of (1), excellent results were obtained in processability and durability. However, because the liquid ethylene-propylene copolymer was added, the product had a high dynamic magnification and did not provide satisfactory results in anti-vibration characteristics. There was a problem that the degree of freedom in characteristic tuning became narrow.

In the case of the sample of Comparative Example 5, although the rubber composition satisfies the characteristics of the claims, | (kd _min
-10) Since the value of -kd | was as large as 50, the product dynamic magnification was increased. In the case of the sample of Comparative Example 6, although it was a fluid-filled type vibration damping device, an insufficient result was obtained in heat resistance because it was made of an NR-based material. On the other hand, in the frequency characteristics, since it is a fluid filled type vibration damping device,
It can be seen that the dynamic spring constant reduction effect is further obtained as compared with the sample of Comparative Example 1 (described later with reference to FIG. 2).

In the case of the sample of Comparative Example 7, in order to further improve the product dynamic magnification as compared with Comparative Example 4, a part of carbon black was changed to silane-treated silica as a compounding agent. A sufficient reduction effect was not obtained in the product dynamic magnification, and the workability was slightly deteriorated. The sample of Comparative Example 8 is an example in which silane-treated silica was used without using carbon black as a compounding agent, as compared with Comparative Example 7, but a workable product was extremely poor, and a practical product was produced. And each measurement could not be performed.

FIG. 2 shows a frequency characteristic diagram of the dynamic spring constant of the engine mount in each of the samples of Example 3 and Comparative Examples 1 and 6. According to the curve A in FIG.
It can be seen that, in the sample No. 2, a sufficient effect of reducing the dynamic spring constant can be obtained in the frequency range of interest. Comparative Example 1
, It can be seen from the curve B that the spring constant increases as the characteristic frequency of the vibration isolator made of rubber alone increases. In Comparative Example 6, it can be seen from the curve C that the dynamic spring constant reduction effect is further obtained as compared with Comparative Example 1.

[0063]

As described above, according to the present invention, the rubber elastic member interposed between the mounting bracket on the power unit including the engine and the mounting bracket on the vehicle body is a fluid-filled vibration-proof support. Therefore, excellent vibration isolation characteristics are obtained by the resonance phenomenon of the incompressible fluid in the orifice that connects the first fluid chamber and the second fluid chamber of the vibration isolation support, and the vibration isolation support is specified. Of ethylene-propylene-non-conjugated diene copolymer rubber as a main component, formed by a rubber composition containing a specific amount of sulfur and carbon black,
And the minimum value of the dynamic spring constant is | (kd _min −10) −kd
By satisfying | ≦ 20 (Hz), excellent vibration isolation, durability, low-temperature flexibility, and heat resistance required for an engine mount insulator can be maintained at a high level.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view of an engine mount insulator showing a typical embodiment of the present invention.

FIG. 2 is a frequency characteristic diagram of an engine mount dynamic spring constant.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Mounting bracket on the power unit side 2 ... Mounting bracket on the vehicle body side 3 ... Rubber (rubber-like) elastic body 4 ... Fluid chamber 5 ... Diaphragm 6 ... First fluid chamber 7 ... Second fluid chamber 8 ... Partition member 9 ... Orifice

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (reference) // C08J 5/00 CES C08J 5/00 CES F term (reference) 3D035 BA01 CA05 3J047 AA03 CA02 CD02 FA02 4F071 AA15X AA20X AA21X AA80 AA81 AB03 AB04 AH19 BC07 4J002 BB151 BB152 DA037 DA046 FD017 FD020 FD146 FD150 GM00

Claims (2)

[Claims] 1. A rubber composition containing a specific amount of carbon black and sulfur in an ethylene / propylene / non-conjugated diene copolymer rubber having a specific ethylene content, iodine value, melt flow index and viscosity, is prevented. In an engine mount insulator used as a rubber elastic support of a vibration device, the rubber elastic support is made of ethylene, propylene, and a non-conjugated diene, and a molar ratio of the ethylene to propylene is 60/40 to 73.
/ 27, value Q of molecular weight distribution measured by GPC measurement method
Is less than 4, intrinsic viscosity (η) measured in decalin at 135 ° C. is 3.0 to 5.0 dl / g, and iodine value is 10 to 4
0 and the non-conjugated diene is 5-ethylidene-
100 parts by weight of ethylene-propylene-non-conjugated diene copolymer rubber which is 2-norbornene, ethylene and propylene, the molar ratio of ethylene to propylene is 50/50 to 78/22, and 135 ° C. The intrinsic viscosity (η) measured in decalin is 0.
Rubber composition mainly composed of 1 to 70 parts by weight of a liquid ethylene / propylene copolymer of 2 to 0.4 dl / g, 0.1 to 2 parts by weight of sulfur, and 30 to 90 parts by weight of carbon black An engine mount insulator characterized by being formed by: 2. A fluid-filled anti-vibration support is formed using a rubber elastic support made of the rubber composition, and the anti-vibration support is provided in an orifice communicating between the first fluid chamber and the second fluid chamber. In the engine mount insulator which obtains the resonance phenomenon of the incompressible fluid, the fluid-filled type vibration damping device may have | (kd _min −10) −kd | ≦ 20 (Hz) (where kd _min is the frequency of the minimum value of the dynamic spring constant) The engine mount insulator according to claim 1, wherein frequency characteristics satisfying the following equation are set.