JP2011046795A - Vibration-damping rubber composition and vibration-damping rubber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration-damping rubber composition providing a cured rubber product that has not only excellent fracture characteristics and vibration-damping performance (low dynamic-to-static modulus ratio) but also excellent kinetic properties and durability even when used under high-temperature conditions, such as an engine room of an automobile, thereby requiring high heat aging resistance, and vibration-damping rubber obtained by curing the rubber composition. <P>SOLUTION: The vibration-damping rubber composition includes natural rubber (NR) and ethylene-propylene-diene rubber (EPDM) as rubber components at a mass ratio [NR/EPDM] of 70/30 to 45/55, also includes only peroxide as a vulcanizing agent, and includes zinc (meth)acrylate and a bismaleimide compound as a co-crosslinking agent. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an anti-vibration rubber composition that can be suitably used in a high-temperature environment and an anti-vibration rubber obtained by curing the composition. In particular, the present invention relates to an anti-vibration rubber composition and an anti-vibration rubber that can be suitably used at high temperature sites such as automobile torsional dampers, engine mounts, and muffler hangers.

  Conventionally, in various vehicles such as automobiles, in order to improve the comfort of passengers, various anti-vibration materials have been arranged at sites that are sources of vibration and noise to reduce the intrusion of vibration and noise into the room. Attempts have been made. For example, for engines that are the main source of vibration and noise, vibrations during engine drive are absorbed by using anti-vibration rubber for components such as torsional dampers, engine mounts, and muffler hangers. Reduces the intrusion of vibration and noise and the spread of noise to the surrounding environment.

  As a basic characteristic of such an anti-vibration rubber, a strength characteristic that supports a heavy object such as an engine and an anti-vibration performance that absorbs and suppresses the vibration are required. Furthermore, when used in a high-temperature environment such as an engine room, it has excellent strength characteristics, low dynamic magnification and excellent anti-vibration performance, as well as high heat resistance, ozone resistance and creep resistance. Is required. In particular, in recent years, the temperature in the engine room has been rising due to higher engine output and space saving in the engine room due to expansion of the indoor space, etc. It has become tough.

  Until now, natural rubber (NR), which has excellent physical properties such as fracture characteristics, has been often used as the rubber component of the vibration-proof rubber. However, although NR is excellent in destructive properties and the like, heat resistance and ozone resistance are inferior to that of synthetic rubber, so that heat resistance and ozone resistance are insufficient when used in a high temperature environment.

  Under such circumstances, in order to improve the heat resistance and ozone resistance characteristics of the anti-vibration rubber, part or all of the NR is replaced with ethylene / propylene / diene rubber (EPDM) and peroxide crosslinking is performed. ing. For example, JP-A-4-246448 (Patent Document 1) discloses a technique for improving heat resistance by adding unsaturated fatty acid zinc to EPDM alone, and JP-A-7-268147 (Patent Document 2). ) And JP-A-7-268148 (Patent Document 3) describe a rubber composition for heat- and vibration-proof rubber that provides a heat-and-vibration-proof rubber with improved durability by subjecting specific EPDM to peroxide crosslinking. Proposed. However, with these methods, there is a risk that the rubber properties such as tensile strength (room temperature, high temperature) and tearing properties and durability will be significantly reduced. Furthermore, the dynamic magnification, which is an important characteristic of the vibration-proof rubber, is increased, and the obtained cured product is often inferior in performance.

  On the other hand, as a vibration-proof rubber whose performance has been improved by other methods, a rubber molded product with high hardness and low dynamic ratio, which is based on a specific chloroprene-based rubber and contains a specific amount of carbon black and a softening agent. Heat-resistant and dynamic vulcanized with a peroxide using a rubber composition (Japanese Patent Laid-Open No. 8-127673: Patent Document 4) and an ethylene-α-olefin copolymer rubber containing no conjugated diene Anti-vibration rubber (Japanese Patent Laid-Open No. 1-299806: Patent Document 5) having excellent sag properties has been proposed, but further improvement is desired. In addition, in order to obtain an anti-vibration rubber composition capable of obtaining excellent anti-vibration performance, a technique using only a specific bismaleimide compound as a vulcanizing agent in a diene rubber (Japanese Patent Application Laid-Open No. 2006-273394: Patent Document) 6) has also been proposed, but it is also desirable to further improve the various properties of the anti-vibration rubber.

  Therefore, even in a high temperature environment such as an engine room of an automobile, the vibration-proof rubber not only has excellent fracture characteristics and vibration-proof performance (low dynamic magnification), but also exhibits excellent heat resistance, durability and creep resistance. Development is desired.

JP-A-4-246448 JP 7-268147 A JP 7-268148 A JP-A-8-127673 Japanese Patent Laid-Open No. 1-299806 JP 2006-273941 A

  The present invention has been made in view of the above circumstances, and when used in a high temperature environment such as an engine room of an automobile, it has not only excellent fracture characteristics and vibration isolation performance (low dynamic magnification) but also heat resistance. An object of the present invention is to provide an anti-vibration rubber composition from which a cured rubber having excellent durability and creep resistance can be obtained, and an anti-vibration rubber obtained by curing the rubber composition.

  As a result of intensive studies to achieve the above object, the present inventor has blended NR and EPDM at a specific ratio to form a rubber component, and blends only a peroxide as a vulcanizing agent and a co-crosslinking agent. By adding (meth) zinc acrylate and bismaleimide compound and co-crosslinking between NR, EPDM and different polymers, the dynamic ratio and creep resistance can be reduced without deteriorating the fracture characteristics, fatigue characteristics and heat resistance. The present inventors have found that a cured rubber product having vibration-proof performance can be obtained, and have made the present invention.

Accordingly, the present invention provides the following anti-vibration rubber composition and anti-vibration rubber.
[1] Natural rubber (NR) and ethylene / propylene / diene rubber (EPDM) are contained as a rubber component in a mass ratio of NR / EPDM = 70/30 to 45/55, and only a peroxide is used as a vulcanizing agent. An anti-vibration rubber composition comprising zinc (meth) acrylate and a bismaleimide compound as a co-crosslinking agent.
[2] The zinc (meth) acrylate (X) is 2 to 4.5 parts by mass, the bismaleimide compound (Y) is 1 to 2 parts by mass, and the (X ) And (Y) in a total amount of 3 to 6.5 parts by mass, [1].
[3] The anti-vibration rubber composition according to [1] or [2], including a fatty acid ester.
[4] The anti-vibration rubber composition according to [3], wherein the zinc (meth) acrylate and the fatty acid ester are premixed and blended.
[5] The anti-vibration rubber composition according to [3] or [4], including 0.2 to 0.6 parts by mass of the fatty acid ester with respect to 100 parts by mass of the rubber component.
[6] Any one of [1] to [5], wherein the bismaleimide compound is N, N′-m-phenylenebismaleimide and / or N, N ′-(4,4′-diphenylmethane) bismaleimide. Anti-vibration rubber composition according to item.
[7] A vibration-proof rubber obtained by curing the rubber composition described above.

  The anti-vibration rubber composition of the present invention has excellent fracture characteristics, heat resistance, durability, dynamic magnification (anti-vibration performance) and creep resistance, and is preferably used in a high temperature environment such as an engine room of an automobile. An anti-vibration rubber that can be obtained is obtained.

  The anti-vibration rubber composition of the present invention contains natural rubber (NR) and ethylene / propylene / diene rubber (EPDM) in a predetermined ratio as rubber components, contains only peroxide as a vulcanizing agent, and is a co-crosslinking agent. As including zinc (meth) acrylate.

  The rubber component includes NR and EPDM. At that time, the blending ratio of NR and EPDM is usually in the range of NR / EPDM = 70/30 to 45/55 in terms of mass ratio. If the ratio of EPDM is less than the above range, ozone resistance and heat resistance may be reduced, and if it is too high, dynamic magnification may be increased, and durability and strength may be reduced. The NR and EPDM may be appropriately selected from known ones and are not particularly limited.

  Further, in the present invention, the rubber component containing NR and EPDM is used as described above. However, as long as it does not deviate from the purpose, other rubbers such as a known synthetic rubber are used in addition to the rubber component as necessary. May be used in combination. Specific examples thereof include butadiene rubber, styrene / butadiene rubber, isoprene rubber, chloroprene rubber, isobutylene / isoprene rubber, acrylonitrile / butadiene rubber, silicone rubber, acrylic rubber, epoxidized natural rubber, acrylate butadiene rubber and the like, and these Examples include synthetic rubbers or natural rubbers whose molecular chain ends are modified, and one or more of them may be appropriately selected and used. When blending the rubber, it is preferably 20% by mass or less (0 to 20% by mass) based on the total amount of the rubber components.

  As the vulcanizing agent, only peroxide is used in the present invention. In the present invention, by peroxide-crosslinking the rubber component using only a peroxide as a vulcanizing agent, heat resistance and creep resistance at high temperatures are excellent as compared with the case of crosslinking using sulfur. Therefore, the heat resistance and durability of the anti-vibration rubber can be improved. As the peroxide, those normally used in this field can be blended, and specific examples thereof include dicumyl peroxide, benzoyl peroxide, 1,1-bis (t-butylperoxy) -3, 5,5-trimethylcyclohexane, diisobutyryl peroxide, cumylperoxyneodecanoate, di-n-propylperoxydicarbonate, diisopropylperoxydicarbonate, di-sec-butylperoxydicarbonate, 1,1, 3,3-tetramethylbutylperoxyneodecanoate, di (4-t-butylcyclohexyl) peroxydicarbonate, di (2-ethylhexyl) peroxydicarbonate, t-hexylperoxyneodecanoate, t-butyl peroxyneodecanoate, t-butyl peroxy Oxyneoheptanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, di (3,5,5-trimethylhexanoyl) peroxide, dilauroyl peroxide, 1,1,3,3- Tetramethylbutylperoxy-2-ethylhexanoate, disuccinic acid peroxide, 2,5-dimethyl-2,5-di (2-ethylhexanoylperoxy) hexane, t-hexylperoxy-2-ethylhexa Noate, di (4-methylbenzoyl) peroxide, t-butylperoxy-2-ethylhexanoate, di (3-methylbenzoyl) peroxide, benzoyl (3-methylbenzoyl) peroxide, dibenzoyl peroxide 1,1-di (t-butylperoxy) -2-methylcyclohex 1,1-di (t-hexylperoxy) -3,3,5-trimethylcyclohexane, 1,1-di (t-hexylperoxy) cyclohexane, 1,1-di (t-butylperoxy) Cyclohexane, 2,2-di (4,4-di- (t-butylperoxy) cyclohexyl) propane, t-hexylperoxyisopropyl monocarbonate, t-butylperoxymaleic acid, t-butylperoxy- 3,5,5-trimethylhexanoate, t-butyl peroxylaurate, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxy 2-ethylhexyl monocarbonate, t-hexyl peroxybenzoate, 2,5- Di-methyl-2,5-di (benzoylperoxy) hexane, t-butylperoxyacetate 2,2-di- (t-butylperoxy) butane, t-butylperoxybenzoate, n-butyl 4,4-di- (t-butylperoxy) valerate, di (2-t-butylperoxy) Oxyisopropyl) benzene, di-t-hexyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, t-butylcumyl peroxide, di-t-butyl peroxide, p- Menthane hydroperoxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydro Peroxide, t-butyl hydroperoxide and the like. In the present invention, di (2-t-butylperoxy) is used. An isopropyl) benzene, can be suitably used dicumyl peroxide. These can be used individually by 1 type or in mixture of 2 or more types. The compounding amount of these vulcanizing agents is usually 1 to 10 parts by mass, preferably 2 to 8 parts by mass with respect to 100 parts by mass of the rubber component. When the blending amount exceeds 10 parts by mass, the rubber is excessively cured, which may cause a decrease in elongation at break and a decrease in durability. When the amount is less than 1 part by mass, the crosslinking density decreases and the breaking strength decreases. There is a risk of lowering, deterioration of dynamic magnification, deterioration of compression set, deterioration of durability, and the like.

  In addition, in the range which does not deviate from the objective of this invention, sulfur can also be mix | blended as a crosslinking adjuvant. When mix | blending this crosslinking adjuvant, it is preferable to make the compounding quantity into the range of 0.1-0.5 mass part with respect to 100 mass parts of rubber components.

  The co-crosslinking agent is not capable of generating crosslinking points by itself, but is an additive that causes a crosslinking reaction in rubber when used in combination with the above-mentioned peroxide, in order to obtain a desired effect such as dynamic magnification. In addition, zinc (meth) acrylate and a bismaleimide compound are included as essential components.

  The compounding amount of the zinc (meth) acrylate is not particularly limited, but is preferably 2 parts by mass or more, more preferably 3 parts by mass or more, preferably 100 parts by mass or more as the upper limit. 6 mass parts or less, More preferably, it is 5 mass parts or less, More preferably, it is 4.5 mass parts or less. If the blending amount exceeds the above range, the rubber may be cured too much, leading to a decrease in elongation at break, and if the blending amount is less than the above range, the rubber is not sufficiently crosslinked, resulting in a decrease in breaking strength and a dynamic ratio. May increase, compression set may increase.

  In the present invention, the fatty acid ester can be blended with the rubber component together with the zinc (meth) acrylate, thereby improving the dispersibility of the zinc (meth) acrylate with respect to the rubber component during kneading. The mechanical properties of the rubber after vulcanization can be improved. Here, the fatty acid and alcohol constituting the fatty acid ester may both have a linear structure or a branched structure, may be either saturated or unsaturated, and the number of carbon atoms is not particularly limited. . In the present invention, a known fatty acid ester composed of a fatty acid having a chain length of 1 to 30 carbon atoms and an alcohol having a chain length of 1 to 30 carbon atoms can be used. May be ethyl stearate, propyl stearate, butyl stearate, ethyl palmitate, propyl palmitate, butyl palmitate and the like. These can be used alone or in combination of two or more. The amount of the fatty acid ester is preferably 0.02 to 1.2 parts by mass, more preferably 0.2 to 0.6 parts by mass with respect to 100 parts by mass of the rubber component. If the blending amount exceeds 1.2 parts by mass, the rubber may be softened, the workability may be deteriorated, and the dynamic magnification may be deteriorated. If the blending amount is less than 0.02 parts by mass, the dispersibility improvement effect may not be obtained. There is.

  Although this fatty acid ester exhibits an effect of improving dispersibility even when blended separately with the above-mentioned zinc (meth) acrylate at the time of kneading with the rubber component, the (meth) acrylic acid is previously obtained before kneading with the rubber component. By premixing with zinc, the dispersibility of zinc (meth) acrylate in the rubber component can be further improved.

［式中、ｘ及びｙはそれぞれ独立に０〜２０のいずれかの整数を示す。Ｒ²は炭素数５〜１８の芳香族基、又はアルキル基を含む炭素数７〜２４の芳香族基を示す。］ In the present invention, a bismaleimide compound is used together with zinc (meth) acrylate as a co-crosslinking agent. A known bismaleimide compound can be used, and is not particularly limited, but a bismaleimide compound represented by the following structural formula (1) can be preferably used.

[Wherein, x and y each independently represents an integer of 0 to 20. R ² represents an aromatic group having 5 to 18 carbon atoms or an aromatic group having 7 to 24 carbon atoms including an alkyl group. ]

In the above formula, x and y each independently represent an integer of 0 to 20, more preferably an integer of 0 to 10. R ² represents an aromatic group having 5 to 18 carbon atoms or an aromatic group having 7 to 24 carbon atoms including an alkyl group, and specific examples thereof include aromatic groups having the following structures. In the following structure, two bonds are not described, but in the following structure, a divalent group is constituted by two bonds from two carbon atoms arbitrarily selected.

  Specific examples of the bismaleimide compound represented by the structural formula (1) include N, N′-o-phenylene bismaleimide, N, N′-m-phenylene bismaleimide, and N, N′-p-phenylene bis. Maleimide, N, N ′-(4,4′-diphenylmethane) bismaleimide, 2,2-bis- [4- (4-maleimidophenoxy) phenyl] propane, bis (3-ethyl-5-methyl-4-maleimide) Phenyl) methane and the like can be exemplified. In the present invention, N, N′-m-phenylenebismaleimide and N, N ′-(4,4′-diphenylmethane) bismaleimide can be preferably used. In addition, said bismaleimide compound can be used individually by 1 type or in combination of 2 or more types. The blending amount is preferably in the range of 1 to 2 parts by mass with respect to 100 parts by mass of the diene rubber. If the blend amount of the bismaleimide compound is less than 1 part by mass, the sag resistance may be deteriorated, whereas if it exceeds 2 parts by mass, the tensile properties and durability may be deteriorated.

  The total amount (X + Y) of the zinc (meth) acrylate (X) and the bismaleimide compound (Y) is 3 to 6.5 parts by mass with respect to 100 parts by mass of the diene rubber component. It is desirable from the viewpoint of effectively exhibiting the effects of the present invention to be in the range of.

  Moreover, with respect to the rubber component, a vulcanizing agent, a vulcanization accelerator, an anti-aging agent, carbon, zinc white (ZnO), which are usually used in the rubber industry, if necessary within a range not impairing the effects of the present invention. ), Additives such as waxes, antioxidants, fillers, foaming agents, plasticizers, oils, lubricants, tackifiers, petroleum resins, UV absorbers, dispersants, compatibilizing agents, homogenizing agents, etc. Can be blended.

  As the oil, known oils can be used, and are not particularly limited. Specifically, process oils such as aromatic oils, naphthenic oils, paraffin oils, vegetable oils such as palm oil, alkylbenzene oils, etc. Synthetic oil, castor oil, etc. can be used. In the present invention, paraffin oil can be preferably used. These can be used alone or in combination of two or more. The blending amount of these oils is not particularly limited, but can be approximately 15 to 45 parts by mass with respect to 100 parts by mass of the rubber component. If the blending amount deviates from the above range, the kneading workability may be deteriorated. When oil-extended rubber is used for the rubber component, the total amount of oil contained in the rubber and oil added separately during mixing may be adjusted within the above range.

  Known carbon can be used, and is not particularly limited. Examples thereof include carbon black such as SRF, GPF, FEF, HAF, ISAF, SAF, FT, MT, In the present invention, FEF can be preferably used. Moreover, these carbon blacks may be used individually by 1 type, and may use 2 or more types together. The blending amount of these carbon blacks is usually 15 to 60 parts by mass, preferably 20 to 50 parts by mass with respect to 100 parts by mass of the rubber component. When the amount exceeds 60 parts by mass, workability may be deteriorated, and when it is less than 15 parts by mass, adhesion may be deteriorated.

  In the present invention, from the viewpoint of promoting vulcanization, a vulcanization acceleration aid such as zinc white (ZnO) or a fatty acid can be blended. The fatty acid may be saturated, unsaturated, linear or branched fatty acid, and is not particularly limited as the carbon number of the fatty acid. For example, the fatty acid has 1 to 30 carbon atoms, preferably 15 to 15 carbon atoms. 30 fatty acids, more specifically naphthenic acid such as cyclohexane acid (cyclohexanecarboxylic acid), alkylcyclopentane having a side chain, hexanoic acid, octanoic acid, decanoic acid (including branched carboxylic acid such as neodecanoic acid), Saturated fatty acids such as dodecanoic acid, tetradecanoic acid, hexadecanoic acid, octadecanoic acid (stearic acid), unsaturated fatty acids such as methacrylic acid, oleic acid, linoleic acid, linolenic acid, resin acids such as rosin, tall oil acid, abietic acid, etc. Is mentioned. These may be used alone or in combination of two or more. In the present invention, zinc white and stearic acid can be preferably used. The compounding amount of these vulcanization acceleration aids is preferably 1 to 10 parts by mass, more preferably 2 to 7 parts by mass with respect to 100 parts by mass of the rubber component. If the blending amount exceeds 10 parts by mass, workability and dynamic magnification may be degraded, and if it is less than 1 part by mass, vulcanization delay may occur.

  As the anti-aging agent, known ones can be used, and are not particularly limited, and examples thereof include a phenol type anti-aging agent, an imidazole type anti-aging agent and an amine type anti-aging agent. The blending amount of these anti-aging agents is usually 2 to 10 parts by mass, preferably 3 to 7 parts by mass with respect to 100 parts by mass of the rubber component.

  When obtaining the rubber composition of the present invention, there is no particular limitation on the blending method of each of the above components, and all the component raw materials may be blended and kneaded at once, or each component may be divided into two or three stages. You may mix | blend and knead | mix. At that time, by premixing with the fatty acid ester before kneading the (meth) zinc acrylate with the rubber component, the dispersibility of the (meth) zinc acrylate in the rubber component is further improved, and the resulting rubber The mechanical properties can be further improved. In the kneading, a kneader such as a roll, an internal mixer, a Banbury rotor or the like can be used. Furthermore, when forming into a sheet shape or a belt shape, a known molding machine such as an extrusion molding machine or a press machine may be used.

  Moreover, there are no particular limitations on the vulcanization conditions for curing the rubber composition, but vulcanization conditions can be generally employed at 140 to 180 ° C. for 5 to 120 minutes.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated in detail, this invention is not restrict | limited to the following Example.

[Examples 1-12, Comparative Examples 1-9]
The rubber composition for vibration-proof rubber of each of Examples 1 to 12 and Comparative Examples 1 to 9 is vulcanized and cured under predetermined conditions by kneading and vulcanizing with the composition shown in Table 1 and Table 2 below. A sheet molded product having a thickness of 120 mm, a width of 120 mm, and a thickness of 2 mm was produced. This sheet was used as an evaluation body of the vibration-proof rubber of the present invention. About the obtained rubber sheet, hardness (Hd), tensile elongation (Eb), tensile strength (Tb), heat resistance, settling resistance (compression set), static spring constant (Ks), dynamic magnification (Kd / Ks) ) Was measured and evaluated according to the following JIS standards. The results are also shown in Tables 1 and 2.

[Hardness (Hd)]
Conforms to JIS K 6253 (Type A).
[Tensile elongation (Eb)]
Conforms to JIS K 6251. When Eb was 400% or more, it was judged as “good”.
[Tensile strength (Tb)]
Conforms to JIS K 6251. When Tb was 10 MPa or more, it was judged as “good”.
[Heat resistance (heat aging test)]
In accordance with JIS K 6257, the test piece was allowed to stand under the conditions of 100 ° C. and 96 hours, and then the hardness (Hd), tensile elongation (Eb), and tensile strength (Tb) were measured. For hardness (Hd), change values (degrees) are shown, and for tensile elongation (Eb) and tensile strength (Tb), retention (%) is shown. It was judged as “good” when the retention rate was 95% or more.
[Compression set]
Conforms to JIS K 6262. The target value was within 30% of compression set (CS).
[Static spring constant (Ks) and dynamic magnification (Kd / Ks)]
According to JIS K 6385, Kd was measured at 100 Hz. The dynamic magnification (Kd / Ks) was set to a target value within 1.5.

Details of the above formulation are as follows.
(1) NR: Natural rubber, “RSS # 1”
(2) EPDM: “EP96” manufactured by JSR, ENB content 6.0% by mass, ethylene content 66% by mass (when the rubber component is “100 parts by mass”, 50 parts by mass of oil is included.)

(3) FEF grade carbon black: “N550” manufactured by Asahi Carbon Co., Ltd., iodine absorption amount 43 g / kg, DBP absorption amount (A method) 121 ml / 100 g
(4) Anti-aging agent: 2,2,4-trimethyl-1,2-dihydroquinoline polymer, “NOCRACK 224” manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
(5) Oil: Paraffin oil (6) Peroxide: Di (2-t-butylperoxyisopropyl) benzene, “Peroximon F-40” manufactured by NOF Corporation
(7) Zinc acrylate, “SR633” manufactured by Sartomer
(8) Zinc methacrylate "SR634" manufactured by Sartomer
(9) N, N'-m-phenylene bismaleimide, "Barunok PM" manufactured by Ouchi Shinsei Chemical Co., Ltd.
(10) N, N ′-(4,4′-diphenylmethane) bismaleimide, “BMI-RB” manufactured by Daiwa Kasei Kogyo Co., Ltd.

  As shown in Tables 1 and 2 above, the rubber compositions of the examples according to the present invention were blended with NR and EPDM at a specific ratio to form a rubber component, and only a peroxide as a vulcanizing agent was blended therewith. A combination of zinc (meth) acrylate and a bismaleimide compound as a co-crosslinking agent. As a result, the rubber compositions of these examples have good rubber properties (hardness, tensile strength, elongation) and also have excellent durability, sag resistance, heat resistance, and dynamic magnification. Was confirmed.

Claims (7)

  Natural rubber (NR) and ethylene / propylene / diene rubber (EPDM) are contained as a rubber component in a mass ratio of NR / EPDM = 70/30 to 45/55, and only a peroxide is contained as a vulcanizing agent. An anti-vibration rubber composition comprising zinc (meth) acrylate and a bismaleimide compound as a co-crosslinking agent.   With respect to 100 parts by mass of the rubber component, 2 to 4.5 parts by mass of the zinc (meth) acrylate (X), 1 to 2 parts by mass of the bismaleimide compound (Y), and the (X) and ( The anti-vibration rubber composition according to claim 1, wherein the total amount of Y) is 3 to 6.5 parts by mass.   The anti-vibration rubber composition according to claim 1 or 2, comprising a fatty acid ester.   The anti-vibration rubber composition according to claim 3, wherein the zinc (meth) acrylate and the fatty acid ester are premixed.   The anti-vibration rubber composition according to claim 3 or 4, comprising 0.2 to 0.6 parts by mass of the fatty acid ester with respect to 100 parts by mass of the rubber component.   The vibration isolating apparatus according to any one of claims 1 to 5, wherein the bismaleimide compound is N, N'-m-phenylenebismaleimide and / or N, N '-(4,4'-diphenylmethane) bismaleimide. Rubber composition.   Anti-vibration rubber obtained by curing the rubber composition according to any one of claims 1 to 6.