JP2005113093A - Heat-resistant rubber vibration isolator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure specified vibration damping characteristics and realize enhancement in molding properties while sufficiently inhibiting deterioration in physical properties such as tensile strength at break or the like even when used for long hours in high-temperature environments by enhancing heat-ageing resistance. <P>SOLUTION: The heat-resistant rubber vibration isolator is molded by vulcanizing a composition comprising an EPDM rubber having incorporated reinforcing agents and vulcanizing agents therewith, and the vulcanization molding is carried out using as the vulcanizing agent a dialkyl peroxide having a half-value period at 145°C of 0.35-0.45 hr. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is used for preventing transmission of vibrations and shocks in structures such as various vehicles, machines, bridges, and railway tracks, and in particular, for example, engine mounts, body mounts, cab mounts, member mounts, strut mounts, center bearings. The present invention relates to a heat-resistant anti-vibration rubber useful as an anti-vibration for automobiles such as supports, torsional dampers, muffler hangers, suspension bushes and the like that are used in a high temperature environment.

  In the anti-vibration rubber for automobiles used in the high temperature environment such as the engine mount and the muffler hanger described above, anti-vibration characteristics are required to prevent vibration and impact transmission to the rigid parts. In addition to this, heat resistance is required so that the anti-vibration properties do not change (decrease) even when used for a long time in such a high temperature environment.

  As this type of anti-vibration rubber, vulcanized moldings of synthetic rubber such as natural rubber (NR), butadiene rubber (BR), styrene butadiene rubber (SBR), etc. have been used. Since the component has a double bond in the main chain, it basically lacks heat resistance, and there is a problem that thermal deterioration and dynamic fatigue are remarkable when used in a high temperature environment for a long time.

  In order to eliminate such problems, conventionally, as a heat-resistant rubber material, an ethylene-propylene-diene terpolymer rubber, that is, an EPDM rubber having no double bond in the main chain is used. In addition, this EPDM rubber has been proposed in which peroxide is added as a vulcanizing agent for improving sag resistance, and carbon black is added as a reinforcing agent for improving durability (for example, , See Patent Document 1).

  In addition, the main rubber in anti-vibration rubber to suppress fatigue (sagging), low dynamic spring characteristics (dynamic magnification) and lower durability caused by using EPDM rubber with excellent heat resistance. As a part, an EPDM rubber that is sulfur vulcanized by containing 2.0 phr or less of sulfur or a peroxide vulcanized EPDM rubber is also proposed (for example, see Patent Document 2). .

JP 7-268148 A JP-A-10-159888

  However, in recent years, demands for lower fuel consumption and compliance with exhaust gas regulations have been increasing, and along with this, improvements in physical properties of anti-vibration rubber for automobiles have been strongly demanded. ing. In particular, in the case of a high-performance automobile with low fuel consumption and exhaust gas regulation measures, the exhaust pipe (muffler) that exhausts the exhaust gas to the outside in addition to the engine room is higher than ever ( Therefore, it is very important to take measures against heat aging of a muffler hanger or the like that supports the muffler with such a high temperature on the vehicle body.

  However, as shown in Patent Documents 1 and 2, even conventional anti-vibration rubbers obtained by vulcanizing EPDM rubber, which is a rubber material having excellent heat resistance, are more than described above. In particular, when used in a high temperature environment for a long time, there is a problem that the rubber part is heat-aged, specifically, the rubber hardness of the rubber part is changed and the predetermined vibration-proof characteristic is lowered.

  In addition, as a countermeasure against thermal aging of anti-vibration rubber using EPDM rubber, a means for lowering the temperature of the anti-vibration rubber itself by installing a heat insulating member in the vicinity of the anti-vibration rubber, and heat resistant silicone as a material of the rubber part The use of rubber is also conceivable, but in the former case, there is a problem that the cost is increased due to an increase in the number of parts. In the latter case, the rubber material itself is expensive and the manufacturing process is also difficult. There is a problem that vulcanization equipment dedicated to silicone rubber is required, leading to an increase in manufacturing cost, and that the low physical properties such as breaking strength inherent in silicone rubber are directly reflected in the vibration-proof rubber.

  The present invention has been made in view of the above-described circumstances, and has improved vibration aging resistance and sufficiently suppresses deterioration in physical properties such as breaking strength even when used for a long time in a high-temperature environment, while maintaining predetermined vibration-proof characteristics. It is an object of the present invention to provide a heat-resistant anti-vibration rubber that can secure the above-mentioned property and can also improve the moldability.

In order to achieve the above object, the heat-resistant vibration-proof rubber according to the present invention is a heat-resistant vibration-proof rubber formed by vulcanizing an EPDM-based composition comprising an EPDM-based rubber, a reinforcing agent and a vulcanizing agent. A vibration rubber,
As the vulcanizing agent, a dialkyl peroxide having a half-life at 145 ° C. of 0.35 to 0.45 hours is used.

  That is, in the anti-vibration rubber according to the present invention, a peroxide (peroxide) that directly crosslinks carbon atoms between rubber molecules without interposing other atoms or the like is used as a vulcanizing agent for EPDM rubber. Since it is formed by peroxide vulcanization, compared to the general sulfur vulcanization using sulfur as a vulcanizing agent, the decomposition of rubber molecules due to heat is suppressed and the original EPDM rubber is suppressed. It is possible to maintain physical properties. As a result, even if the anti-vibration rubber is used for a long time in a higher temperature environment, such as a muffler hanger, the rubber part is thermally aged, the rubber molecules are decomposed by heat or excessively between the rubber molecules. Changes in physical properties such as hardness due to the progress of cross-linking, etc. are effectively suppressed, and thus heat resistance can be significantly improved, and conventional anti-vibration rubber is considered unsuitable for use due to changes in anti-vibration properties. It can be used sufficiently even in a high temperature environment.

  Moreover, in the present invention, as a vulcanizing agent used for peroxide vulcanization, a dialkyl peroxide having a half life at 145 ° C. of 0.35 to 0.45 hours, specifically, 2.5-di A composition containing 90% or more of methyl-2.5-di- (t-butylperoxy) hexane, or 2.5-di-methyl-2.5-di- (t-butylperoxy) By using a composition containing 40% hexane and 60% inert filler, it becomes possible to vulcanize at a high temperature and in a short time while maintaining the excellent heat resistance as described above. Further, the molding efficiency of the vibration-proof rubber can be increased.

  In addition, it is preferable that the mixture ratio of the said dialkyl peroxide in the heat resistant vibration-proof rubber which concerns on this invention is 5 to 10 weight% with respect to EPDM type rubber. Here, if it is less than 5% by weight, the crosslink density becomes low, and the dynamic magnification required as a vibration-proof rubber {dynamic spring constant at vibration input of 100 Hz: Kd100 (N / mm) and static spring constant (Ks) Ratio (= Kd100 / Ks)} cannot be made sufficiently small, and if it exceeds 10% by weight, the crosslink density becomes excessively high, and the tensile strength required as an anti-vibration rubber is low. It can no longer be obtained.

  In addition, in the heat resistant vibration isolating rubber according to the present invention, by adding an anti-aging agent to the EPDM rubber composition, fatigue (sagging) generated when using the EPDM rubber is improved, and Heat resistance can be further improved.

  According to the present invention, by using a dialkyl peroxide having a specific half-life as described above as a vulcanizing agent for an EPDM rubber, it is possible to ensure the vibration-isolating characteristics originally required as a vibration-proof rubber. However, it is possible to effectively suppress the deterioration of physical properties such as hardness, tensile strength, and elongation of the rubber part even by using heat aging resistance for a long time in a higher temperature environment than ever, and therefore The conventional anti-vibration rubber can be used for a sufficiently long time even in a high-temperature environment that has been considered unsuitable for use because the anti-vibration properties change.

  Moreover, in the present invention, by using a dialkyl peroxide having a specific half-life, molding of a vibration-proof rubber by vulcanization at a high temperature and in a short time while maintaining the excellent heat aging resistance as described above. There is an effect that the efficiency can be increased and the manufacturing cost of the anti-vibration rubber can be reduced.

  As described above, the heat-resistant vibration-insulating rubber according to the present invention is a vulcanizing agent in a heat-resistant vibration-insulating rubber obtained by vulcanization molding of an EPDM-based composition comprising an EPDM rubber, a reinforcing agent, and a vulcanizing agent. By using a dialkyl peroxide having a half-life of 0.35 to 0.45 hours at 145 ° C., the heat aging resistance of the rubber part is increased, and the breaking strength and the like can be improved even when used for a long time in a high temperature environment. A predetermined vibration-proof characteristic can be secured without deteriorating physical properties.

  Here, the EPDM rubber is an amorphous random elastic copolymer obtained from ethylene and α-olefin as main components and a small amount of non-conjugated diene monomer. Examples of the α-olefin include propylene, butylene (1-butene), isobutylene (2-methylpropene), 1-benten, and the use of propylene is particularly preferable. As the non-conjugated diene monomer, those having about 5 to 20 carbon atoms are used. For example, 1,4-pentadiene, 1,4-hexazine, 1,5-hexazine, 2,5-dimethyl-1,5-hexazine And chain dienes such as 1,4-octadiene, cyclic dienes such as 1,4-cyclohexazine, cyclooctadiene, dicyclopentadiene, 5-ethylidene-2-norbornene, 5-butylidene-2-norbornene, 2-methallyl Examples include alkenyl norbornene such as -5-norbornene and 2-isopropenyl-5-norbornene. Among these, dicyclopentadiene and 5-ethylidene-2-norbornene are preferably used.

  The proportion of the constituent monomer of the EPDM rubber usually contains about 45 to 75% by weight of ethylene and about 4 to 15% by weight of the non-conjugated diene monomer. The average molecular weight of the EPDM rubber is usually about 500,000 to 1,500,000.

Carbon black is used as a reinforcing agent for EPDM rubber. There are no restrictions on the production method and properties of this carbon plaque, and various types can be used, but those having a nitrogen adsorption specific surface area of 15 to 70 m ² / g are excellent in dynamic magnification, tensile strength, and reasoning resistance. The blending ratio of carbona black is not particularly limited, but is usually about 0.1% by weight or more based on the EPDM rubber in order to sufficiently function as a reinforcing agent for the EPDM rubber. Yes, and more preferably 1% by weight or more.

  On the other hand, as a peroxide used as a vulcanizing agent, a dialkyl peroxide having a half-life at 145 ° C. of 0.35 to 0.45 hours, specifically, represented by the following chemical formula 1 , 2.5-di-methyl-2.5-di- (t-butylperoxy) hexane having a composition containing 90% or more (for example, product name “Perhexa 25B” manufactured by NOF Corporation, or , 2.5-di-methyl-2.5-di- (t-butylperoxy) hexane 40% and inert filler 60% (for example, products manufactured by NOF Corporation) The name “Perhexa 25B-40” is used.

  The blending ratio of the above dialkyl peroxide is preferably in the range of 5 to 10% by weight with respect to the EPDM rubber. When the blending ratio is less than 5% by weight, the crosslink density is low, and the dynamic magnification required as a vibration proof rubber {dynamic spring constant at vibration input of 100 Hz: Kd100 (N / mm) and static spring constant ( Ks) ratio (= Kd100 / Ks)} cannot be made sufficiently small, and if the blending ratio exceeds 10% by weight, the crosslinking density becomes excessively high, which is required as a vibration-proof rubber. It is impossible to obtain a high tensile strength.

  In addition, when vulcanizing EPDM rubber, in addition to the above-mentioned carbon black and vulcanizing agent (dialkyl peroxide), a vulcanization accelerator, a vulcanization acceleration auxiliary, an anti-aging agent, a softening agent such as process oil, etc. A suitable amount of rubber additives such as rubber additives are blended in an appropriate amount so as not to impair the properties and characteristics of the vibration-proof rubber. Here, examples of the vulcanization accelerator include Nt-butyl-2-benzothiazolylsulfenamide (BBS), N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), N-oxydiethylene- Sulfenamides such as 2-benzothiazole sulfenamide (OBS); dithiocarbamates such as zinc dimethyldithiocarbamate (ZnMDC) and zinc diethyldithiocarbamate (ZnEDC); tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide ( TETD), thiurams such as tetrabutylthiuram disulfide (TBTD), and the like, and examples of the vulcanization accelerating aid include zinc oxide and stearic acid.

  Softeners include process oils, lubricating oils, petroleum softeners such as paraffin, liquid paraffin, petroleum asphalt, and petroleum jelly, fatty oil softeners such as castor oil, amal oil, rapeseed oil, coconut oil, and tall oil. And waxes such as beeswax, carnauba wax and lanolin.

  Further, as the anti-aging agent, zinc methacrylate represented by the following chemical formula 2 (for example, trade name “Actor ZMA” manufactured by Kawaguchi Chemical Industry Co., Ltd.) and a phenol-based anti-aging agent represented by the following chemical formula 3 (for example, Ciba Specialty Chemicals, trade name “Irganox 1010”), 2-mercaptobenzimidazole (for example, trade name “NOCRACK MB” manufactured by Ouchi Shinsei Chemical) and the like. The blending ratio of this anti-aging agent is usually within the range of 5% by weight or less with respect to the EPDM rubber, and used within the range of 0.5 to 4% by weight which improves the heat resistance of the vulcanized rubber. Is preferred.

  Furthermore, when manufacturing the heat-resistant vibration-proof rubber according to the present invention, various obvious methods can be employed. For example, by using a known kneading apparatus such as a Banbury mixer or a roll machine, the above-mentioned rubber additives such as an EPDM rubber material and a liquid vulcanizing agent are blended and kneaded in the kneading apparatus. An unvulcanized EPDM rubber composition having a structure is prepared. Next, the unvulcanized EPDM rubber composition is molded into a desired shape by a conventionally known molding method such as mold molding, while being heated to a predetermined temperature and vulcanized to thereby achieve the heat resistance according to the present invention. Anti-vibration rubber is manufactured.

  In addition, the charging order when charging various rubber additives such as unvulcanized EPDM rubber and vulcanizing agent into the kneading apparatus is not limited to the order described above. In addition, all rubber raw materials except for the vulcanizing agent and the vulcanization accelerating aid are added and pre-kneaded (base kneading), and then the vulcanizing agent and vulcanized during the final kneading. An acceleration aid may be added.

  In addition, regarding the vulcanization conditions such as vulcanization temperature, pressure, and time in the molding vulcanization operation, the rubber component and the type of vulcanizing agent are taken into account so that the EPDM rubber material can be vulcanized well. The specific method of the molding vulcanization operation is not limited at all, and known means such as press vulcanization that performs vulcanization simultaneously with molding can be employed.

  The heat-resistant anti-vibration rubber manufactured in this way is interposed between members constituting the vibration or shock transmission system in structures such as various vehicles, machines, bridges, railway tracks, etc. Although it is used to realize, especially it is placed under high temperature environment such as engine mount, body mount, cab mount, member mount, strut mount, center bearing support, torsional damper, muffler hanger, suspension bush, etc. It is suitably used as a vibration-proof rubber for automobiles to be used.

  Hereinafter, in order to clarify the present invention more specifically, some examples and comparative examples will be described. However, the present invention is not limited by the description of these examples, and the gist of the present invention is described below. It goes without saying that various changes and improvements can be made without departing from the above.

Examples 1-3 and Comparative Examples 1-3:
After the EPDM rubber material (trade name “Keltan 5631A” manufactured by Idemitsu DSM Co., Ltd.) was mixed with paraffinic oil (trade name “PW-380” manufactured by Idemitsu Kosan Co., Ltd.), the mixture was mixed. Dialkyl peroxide (trade name “Perhexa 25B-40B” manufactured by NOF Corporation), reinforcing agent: carbon black (HAF, trade name “SEAST 3” manufactured by Tokai Carbon Co., Ltd.), vulcanizing agent Sulfur accelerating aid: Zinc oxide (trade name “Zinc Hua 3” manufactured by Mitsui Mining & Smelting Co., Ltd.) + stearic acid (trade name “Lunac S-20” manufactured by Kao Soap Co., Ltd., anti-aging agent (Kawaguchi Chemical) An EPDM rubber composition was prepared by adding and kneading the trade name “ACTOR ZMA” manufactured by Kogyo Co., Ltd. and sulfur (“powder sulfur” manufactured by Hosoi Chemical Co., Ltd.) in the proportions shown in Tables 1 and 2. Then the prepared By vulcanizing the vulcanized EPDM rubber composition by the press vulcanization molding operation method, test pieces for vibration characteristics test, hardness test and tensile test described later (Examples 1 to 3 and Comparative Example) In this case, the vulcanization conditions are as follows: test piece for vibration characteristics test: 170 ° C. × 30 minutes, test piece for hardness test and tensile test: 170 ° C. × 20 minutes, respectively In Comparative Example 3, sulfur was used as a vulcanizing agent.

  As a test piece for the vibration characteristic test, a vulcanized rubber sample having a cylindrical shape with a diameter of 50 mm and a height of 25 mm was prepared by the above vulcanization molding, and then the upper and lower surfaces of the vulcanized rubber sample. On the other hand, a pair of iron disk metal fittings having a diameter of 60 mm and a thickness of 6 mm were prepared by bonding with an adhesive. Further, as a test piece for hardness test, a test piece having a thickness of 2 mm as defined in “Durometer Hardness Test” in “Vulcanized Rubber Physical Test Method” of JIS-K-6253-1997 is prepared. Moreover, as a test piece for the tensile test, a dumbbell-shaped test piece (No. 5) as defined in “Tensile test method for vulcanized rubber” of JIS-K-6251-1993 was prepared.

  Using the test pieces of Examples 1 to 3 and Comparative Examples 1 to 3 of the present invention produced as described above, the following vibration characteristic test, hardness test, and tensile test were performed.

-Vibration characteristic test-
For each test piece for vibration characteristics test, an axial load is applied to compress 5.5 mm in the axial direction. Once the load is reduced, it is compressed again by 5.5 mm. A load-deflection characteristic is measured, and a load-deflection curve is created based on the measured load-deflection characteristic. From the curves, load values P1 and P2 (unit: N) when the deflection becomes 1.25 mm and 3.7 mm are read, respectively, and then the following formula: Ks = (P2 -P1) / 2. 5
Was used to calculate a static spring constant: Ks (N / mm). Separately, after compressing each test piece in the axial direction by 2.5 mm, the amplitude around the position compressed by 2.5 mm from the lower side of the test piece in the compressed state is a constant of ± 0.05 mm. A test for applying displacement harmonic compression vibration at a frequency of 100 Hz is performed, and dynamics at 100 Hz are performed in accordance with “Non-resonant method (a)” in “Testing method of vibration-proof rubber” of JIS-K-6385-1995. Spring constant: Kd100 (N / mm) was determined. Then, the dynamic magnification (= Kd100 / Ks) was calculated from the obtained dynamic spring constant (Kd100) and the calculated static spring constant (Ks), and the results are shown in Table 3. Here, the small dynamic magnification means that the dynamic spring characteristic with respect to the vibration of 100 Hz of the target test piece is low.

  In this vibration characteristic test, each test piece was compressed 2.5 mm in the axial direction, and a constant displacement harmonic compression vibration with an amplitude of ± 0.05 mm centered on the compression position from the bottom of each test piece. In accordance with “Non-resonant method (a)” in “Testing method for anti-vibration rubber” in JIS-K-6385-1995, a loss coefficient at 10 Hz: tan σ (10 Hz) The results are also shown in Table 3. Here, a large value of the loss coefficient means that the attenuation characteristic of the target test piece with respect to vibration of 10 Hz is high.

-Hardness test-
Using each test piece for the hardness test, as described above, according to the “durometer hardness test” of JIS-K-6253-1997, the hardness of each test piece is measured with a type A durometer, As a result, the hardness which is one of the normal physical properties is shown in Table 4 as JIS type A hardness (Hs). On the other hand, a test piece for hardness test prepared separately was inserted and installed in an oven set at 120 ° C., 150 ° C. and 190 ° C., heated for 70 hours (h), allowed to cool to room temperature, and then In addition to measuring the hardness (Hs) by performing the same hardness test as described above, the change in hardness due to heat aging is obtained by the following formula, and this is also shown in Table 4 as one of the physical properties after heat aging. In addition, it is shown in FIG.
Change in hardness (Hs) = Y1 -Y0
Y0: Hardness before heat aging, Y1: Hardness after heat aging

-Tensile test-
As described above, using each test piece for the tensile test, the test piece was pulled until the test piece was broken by the test method specified in JIS-K-6251-1993, and the maximum stress until the breakage (tensile strength) The elongation at break (elongation at break: EB) was measured. As a result, the tensile strength, which is one of the normal physical properties, and the elongation at break were also shown in Table 4. On the other hand, a test piece for a tensile test prepared separately was inserted and installed in an oven set at 120 ° C., 150 ° C., and 190 ° C. and heated for 70 hours (h), as in the case of the hardness test. Allow to cool to room temperature, and then perform the same tensile test as above to measure the tensile strength (TB) and elongation at break (EB). The percent change in elongation (%) was obtained, and these are also shown in Table 4 as physical properties after heat aging, and are also shown in FIGS.
Change rate of TB (EB) = {(X1-X0) / X0} * 100
X0: Tensile strength before heat aging or elongation at break X1: Tensile strength after heat aging or elongation at break

  As is clear from the results of the vibration characteristic test shown in Table 3, the product of the present invention shown in the test pieces of Examples 1 to 3 has a dynamic magnification (= Kd100 / Ks) and a loss coefficient tanσ (10 Hz). It was confirmed that the values were almost the same as those shown in the test pieces of Comparative Examples 1 to 3 and exhibited excellent vibration isolation characteristics.

  On the other hand, as is apparent from the results of normal physical properties and physical properties after heat aging shown in Table 4 and FIGS. 1 to 3, the products of the present invention shown in the test pieces of Examples 1 to 3 are comparative examples 1 to 1. It was confirmed that the tensile strength due to heat aging and the elongation at break were less than those shown in the test piece 3 and the change in hardness was effectively suppressed.

  In addition, since dialkyl peroxides with a half-life at 145 ° C. of 0.35 to 0.45 hours are used as vulcanizing agents, high temperature and short time vulcanization is required for vulcanizing EPDM rubbers. Molding can be carried out, and the manufacturing cost can be reduced by increasing the molding efficiency of the vibration-proof rubber without impairing the heat resistance. That is, Table 5 shows the relationship between the heat resistance of the vibration-proof rubber and the moldability determined by the vulcanization time by using a vulcanizing agent that can obtain a half life of 0.35 to 0.45 hours at a decomposition temperature of 145 ° C. Evaluation as shown in FIG.

  As is clear from Table 5 above, when a dialkyl peroxide having a half-life of less than 0.35 hours at 145 ° C. is used as a vulcanizing agent for EPDM rubber, vulcanization molding in a short time is possible. Thus, the manufacturing cost can be reduced, but the heat aging resistance is lacking, and the physical properties such as the breaking strength when used in a high temperature environment are unavoidable. On the other hand, when using a dialkyl peroxide whose half-life at 145 ° C. exceeds 0.45 hours, excellent heat aging resistance without deterioration of physical properties when used in a high temperature environment can be obtained, but at low temperature and for a long time. Therefore, an increase in the production cost of the vibration-proof rubber is inevitable. In contrast, in the present invention using a dialkyl peroxide having a half-life at 145 ° C. of 0.35 to 0.45 hours, high temperature and short time vulcanization molding is performed while maintaining excellent heat aging resistance. It was found that the manufacturing cost of the anti-vibration rubber can be reduced.

It is a graph which shows the change of the hardness with respect to temperature among the heat aging tests in each of Examples 1-3 and Comparative Examples 1-3 of the anti-vibration rubber according to the present invention. It is a graph which shows the change of the tensile strength with respect to temperature among the heat aging tests in each of Examples 1-3 and Comparative Examples 1-3 of the vibration-proof rubber according to the present invention. It is a graph which shows the change of the elongation at the time of a fracture | rupture with respect to temperature among the heat aging tests in each of Examples 1-3 and Comparative Examples 1-3 of the anti-vibration rubber according to the present invention.

Claims (4)

A heat-resistant vibration-proof rubber formed by vulcanizing an EPDM composition comprising an EPDM rubber, a reinforcing agent and a vulcanizing agent,
A heat-resistant vibration-proof rubber characterized in that a dialkyl peroxide having a half-life at 145 ° C. of 0.35 to 0.45 hours is used as the vulcanizing agent.   The dialkyl peroxide used as the vulcanizing agent has a composition containing 90% or more of 2.5-di-methyl-2.5-di- (t-butylperoxy) hexane. Heat resistant anti-vibration rubber as described in 1.   The dialkyl peroxide used as the vulcanizing agent is a composition containing 40% 2.5-di-methyl-2.5-di- (t-butylperoxy) hexane and 60% inert filler. The heat-resistant anti-vibration rubber according to claim 1. The heat-resistant vibration-insulating rubber according to any one of claims 1 to 3, wherein a blending ratio of the dialkyl peroxide used as the vulcanizing agent is 5 to 10% by weight with respect to the EPDM rubber.

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