Vibration-damping rubber composition and vibration-damping rubber member

Abstract

To provide a vibration-proof rubber composition and a vibration-proof rubber member which are excellent in durability, can achieve a low dynamic-to-static modulus ratio, and can exhibit excellent scorch resistance under a wet heat environment or the like.SOLUTION: The vibration-proof rubber composition comprises a diene rubber composition containing the following (A)-(C) and the following (D) and (E): (A) a diene rubber; (B) silica; (C) a silane coupling agent; (D) N-oxydiethylene-2-benzothiazolylsulfenamide; and (E) di-2-benzothiazolyl disulfide. The total content of (D) and (E) is 1-5 pts.mass based on 100 pts.mass of (A), and the mass ratio of (D) to (E) is (D):(E)=90:10-50:50.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a vibration isolation rubber composition and a vibration isolation rubber member used for vibration isolation applications in vehicles such as automobiles and trains.

Background Art

[0002] In the technical field of vibration isolation rubber, high durability, reduction of the dynamic magnification ratio (reducing the value of the dynamic magnification ratio [dynamic spring constant (Kd) / static spring constant (Ks)]), etc. are required. In order to achieve these requirements, a diene rubber which is a polymer of a vibration isolation rubber composition contains fillers such as carbon black and silica, and further, a compounding system in which a silane coupling agent is used in combination to improve the dispersibility of silica has been established (for example, see Patent Documents 1 to 4). Furthermore, for further reduction of the dynamic magnification ratio, together with high dispersion of silica, the crosslinking structure of the polymer rubber and the bonding property between silica and the polymer rubber by the silane coupling agent become important.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in conventional vibration-damping rubber compositions containing silica and silane coupling agents, as described above, the rubber composition is more prone to scorching (rubber burning) than when using carbon black as silica (filler), especially in humid environments (high temperature and humidity conditions), which can cause problems during long-term storage.

[0005] This invention has been made in view of these circumstances, and aims to provide an anti-vibration rubber composition and anti-vibration rubber member that are highly durable, can achieve low dynamic magnification, and exhibit excellent scorch resistance in humid and hot environments. [Means for solving the problem]

[0006] The inventors diligently conducted research to solve the aforementioned problems. In the course of this research, in order to achieve high durability and low dynamic magnification, they developed a compound system in which silica and a silane coupling agent are used in combination with diene rubber, which is the polymer of the vibration-damping rubber composition, and in order to improve the scorch resistance of this compound system, they conducted extensive research, mainly on vulcanization accelerators. In such formulations, N-cyclohexyl-2-benzothiazolyl sulfenamide (CBS) is a commonly used vulcanization accelerator that can achieve a low dynamic ratio. However, in the presence of hygroscopic silica, CBS is prone to hydrolysis in a humid and hot environment, transforming into 2-mercaptobenzothiazole (MBT), which has a higher vulcanization-promoting effect. As a result, it exhibits the effect of shortening the scorch time, which presents a problem. Therefore, the inventors selected N-oxydiethylene-2-benzothiazolyl sulfenamide (MBS) and di-2-benzothiazolyl disulfide (MBTS) as vulcanization accelerators that are less susceptible to hydrolysis compared to CBS, and verified their effectiveness by replacing CBS with these. The results of this verification showed that when using MBS, the scorch time under humid heat conditions could be made at the same level as when using carbon black, but under dry heat conditions (high temperature and low humidity conditions), the scorch time tended to increase in the early stages of time, making it difficult to handle in actual processes. Furthermore, the results of this verification showed that when using MBTS, the scorch time under humid heat conditions could be made at a level higher than when using carbon black, but the deterioration of dynamic properties was significant. However, through repeated experiments, the inventors discovered that by combining MBS and MBTS in specific proportions, the advantages of each can be brought out. Furthermore, they found that with this configuration, in a compound system using silica and a silane coupling agent with diene rubber, it is possible to achieve a low dynamic ratio comparable to that when using CBS, and to obtain excellent scorch resistance (scorch time at the same level as when carbon black is used), which could not be obtained with CBS or conventional combinations of vulcanization accelerators.

[0007] In other words, the gist of the present invention is as follows: [1] to [5]. [1] A vibration-damping rubber composition comprising a diene rubber composition containing the following (A) to (C) and also containing the following (D) and (E), The total content of (D) and (E) is 1 to 5 parts by mass per 100 parts by mass of (A). A vibration-damping rubber composition in which the mass ratio of (D) to (E) is (D):(E) = 90:10 to 50:50. (A) Diene-based rubber. (B) Silica. (C) Silane coupling agent. (D)N-oxydiethylene-2-benzothiazolyl sulfenamide. (E) di-2-benzothiazolyl disulfide. [2] The vibration-damping rubber composition according to [1], wherein the content of (B) is 5 to 100 parts by mass per 100 parts by mass of (A). [3] The vibration-damping rubber composition according to [1] or [2], wherein the content of (C) is 2 to 12 parts by mass per 100 parts by mass of (A). [4] The vibration-damping rubber composition according to any one of [1] to [3], wherein (C) is at least one selected from the group consisting of mercapto-silane coupling agents and sulfide-silane coupling agents. [5] A vibration-damping rubber member comprising a vulcanized body of any of the vibration-damping rubber compositions described in [1] to [4]. [Effects of the Invention]

[0008] Thus, the vibration-damping rubber composition of the present invention contains a polymer made of diene rubber (A), silica (B), a silane coupling agent (C), and further contains N-oxydiethylene-2-benzothiazolyl sulfenamide (D) and di-2-benzothiazolyl disulfide (E), which are vulcanization accelerators, in specific proportions. Therefore, it is possible to achieve high durability and low dynamic magnification while exhibiting excellent scorch resistance. [Modes for carrying out the invention]

[0009] Next, embodiments of the present invention will be described in detail. However, the present invention is not limited to these embodiments. In this invention, when "X~Y" (where X and Y are any numbers) is used, unless otherwise specified, it means "X or greater and Y or less," and also includes the meaning of "preferably greater than X" or "preferably less than Y." Furthermore, when expressed as "X or greater" (where X is any number) or "Y or less" (where Y is any number), it also implies the intention that "it is preferable that it be greater than X" or "it is preferable that it be less than Y."

[0010] The anti-vibration rubber composition according to one embodiment of the present invention (hereinafter referred to as "this anti-vibration rubber composition") is a diene rubber composition containing the following (A) to (C) and containing the following (D) and (E), and the total content of (D) and (E) is 1 to 5 parts by mass with respect to 100 parts by mass of (A), and the mass ratio of (D) to (E) is (D):(E) = 90:10 to 50:50. (A) Diene rubber. (B) Silica. (C) Silane coupling agent. (D) N-oxydiethylene-2-benzothiazolylsulfenamide (MBS). (E) Di-2-benzothiazolyldisulfide (MBTS).

[0011] As described above, since this anti-vibration rubber composition is a diene rubber composition, diene rubber (A) is used for its polymer. In addition, since it is a diene rubber composition as described above, it is desirable not to use polymers other than diene rubber (A) in this anti-vibration rubber composition, but it is also possible to use polymers other than diene rubber (A) if the amount is small (less than 30% by mass of the total polymer).

[0012] Hereinafter, the constituent materials of this anti-vibration rubber composition will be described in detail.

[0013] [Diene rubber (A)] As the diene rubber (A) used in this anti-vibration rubber composition, preferably, a diene rubber mainly composed of natural rubber (NR) is used. Here, "main component" means that 50% by mass or more of the diene rubber (A) is natural rubber, preferably 80% by mass or more of the diene rubber (A), more preferably 90% by mass or more of the diene rubber (A) is natural rubber, and it is intended to include those in which the diene rubber (A) consists only of natural rubber. Thus, by using natural rubber as the main component, it becomes excellent in terms of strength and reduction of dynamic magnification. In addition, examples of diene rubbers other than natural rubber include butadiene rubber (BR), styrene-butadiene rubber (SBR), chloroprene rubber (CR), isoprene rubber (IR), acrylonitrile-butadiene rubber (NBR), ethylene-propylene-diene rubber (EPDM), butyl rubber (IIR), chloroprene rubber (CR), and the like. These may be used alone or in combination of two or more. In addition, it is desirable to use these diene rubbers in combination with natural rubber.

[0014] 〔Silica (B)〕 In addition, examples of the silica (B) used in the present vibration-proof rubber composition include wet silica, dry silica, colloidal silica, and the like. These may be used alone or in combination of two or more.

[0015] From the viewpoint of achieving both high durability and low dynamic magnification, the BET specific surface area of the silica (B) is preferably 20 to 380 m 2 / g. In addition, the BET specific surface area of the silica (B) can be measured, for example, by using a BET specific surface area measuring device (manufactured by Micro Data Co., Ltd., 4232-II) with a mixed gas (N2: 70%, He: 30%) as the adsorbed gas after degassing the sample at 200 °C for 15 minutes.

[0016] From the viewpoints of achieving high durability and low dynamic magnification, the content of the silica (B) is preferably 5 to 100 parts by mass with respect to 100 parts by mass of the diene rubber (A). From the same viewpoint, more preferably, it is 10 to 80 parts by mass, and still more preferably, it is 15 to 75 parts by mass.

[0017] 〔Silane coupling agent (C)〕 Furthermore, as the silane coupling agent (C) used in this vibration-damping rubber composition, for example, mercapto-silane coupling agents, sulfide-silane coupling agents, amine-silane coupling agents, epoxy-silane coupling agents, vinyl-silane coupling agents, etc., can be used alone or in combination of two or more. Among these, it is preferable that the silane coupling agent (C) be a mercapto-silane coupling agent or a sulfide-silane coupling agent, as this increases the vulcanization density and is particularly effective in lowering the dynamic magnification and improving durability.

[0018] Examples of the mercapto-silane coupling agents include 3-mercaptopropyltrimethoxysilane and 3-mercaptopropyltriethoxysilane. These can be used alone or in combination of two or more.

[0019] Examples of the sulfide-based silane coupling agents include bis-(3-(triethoxysilyl)-propyl)-disulfide, bis(3-triethoxysilylpropyl)trisulfide, bis-(3-(triethoxysilyl)-propyl)-tetrasulfide, bis(3-trimethoxysilylpropyl)disulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, bis(3-triethoxysilylpropyl)disulfide, and 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide. Examples include rasulfide, 3-triethoxysilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, 2-trimethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazolyl tetrasulfide, 3-triethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, and 3-trimethoxysilylpropyl methacrylate monosulfide. These can be used individually or in combination of two or more.

[0020] Examples of the amine-based silane coupling agents include 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, and 3-(N-phenyl)aminopropyltrimethoxysilane. These can be used alone or in combination of two or more.

[0021] Examples of the epoxy-based silane coupling agents include 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, and 3-glycidoxypropylmethyldimethoxysilane. These can be used individually or in combination of two or more.

[0022] Examples of the vinyl-based silane coupling agents include vinyltriethoxysilane, vinyltrimethoxysilane, vinyltris(β-methoxyethoxy)silane, vinyldimethylchlorosilane, vinyltrichlorosilane, vinyltriisopropoxysilane, and vinyltris(2-methoxyethoxy)silane. These can be used alone or in combination of two or more.

[0023] The content of these silane coupling agents (C) is preferably 2 to 12 parts by mass, and more preferably 3 to 10 parts by mass, per 100 parts by mass of the diene rubber (A), from the viewpoint of achieving high durability and low dynamic magnification.

[0024] [Vulcanization accelerators (D), (E)] Furthermore, as the vulcanization accelerator used in this vibration-damping rubber composition, a specific vulcanization accelerator, namely N-oxydiethylene-2-benzothiazolyl sulfenamide (MBS) shown in (D) above and di-2-benzothiazolyl disulfide (MBTS) shown in (E) above, is used in combination. Furthermore, in this vibration-damping rubber composition, the total content of MBS(D) and MBTS(E) is 1 to 5 parts by mass, preferably in the range of 1.5 to 5 parts by mass, and more preferably in the range of 2 to 5 parts by mass, per 100 parts by mass of the diene rubber (A). Furthermore, in this vibration-damping rubber composition, the mass ratio of MBS(D) to MBTS(E) is (D):(E)=90:10 to 50:50, and preferably (D):(E)=85:15 to 55:45. By using MBS(D) and MBTS(E) in this mass ratio, it becomes possible to achieve a lower dynamic magnification in this vibration-damping rubber composition while obtaining excellent scorch resistance that could not be obtained with conventional combinations of vulcanization accelerators.

[0025] In addition, this vibration-damping rubber composition may also contain, as needed, vulcanizing agents, vulcanizing aids, antioxidants, process oils, carbon black, etc., along with the essential components (A) to (E) mentioned above.

[0026] Examples of the aforementioned vulcanizing agents include sulfur (powdered sulfur, precipitated sulfur, insoluble sulfur), sulfur-containing compounds such as alkylphenol disulfides, etc. These can be used alone or in combination of two or more.

[0027] Furthermore, the content of the vulcanizing agent is preferably in the range of 0.1 to 10 parts by mass, and particularly preferably in the range of 0.3 to 5 parts by mass, per 100 parts by mass of the diene rubber (A). This is because if the content of the vulcanizing agent is too low, the vulcanization reactivity tends to deteriorate, and conversely, if the content of the vulcanizing agent is too high, the rubber properties (breaking strength, elongation at break) tend to decrease.

[0028] Examples of the aforementioned vulcanization aids include zinc oxide (ZnO), stearic acid, and magnesium oxide. These can be used individually or in combination of two or more.

[0029] Furthermore, when the vulcanization aid is used, its content is preferably in the range of 0.1 to 10 parts by mass, and particularly preferably in the range of 0.3 to 7 parts by mass, per 100 parts by mass of the diene rubber (A).

[0030] Examples of the aforementioned antioxidants include carbamate-based antioxidants, phenylenediamine-based antioxidants, phenol-based antioxidants, diphenylamine-based antioxidants, quinoline-based antioxidants, imidazole-based antioxidants, and waxes. These can be used individually or in combination of two or more.

[0031] Furthermore, when the aforementioned antioxidant is used, its content is preferably in the range of 0.5 to 15 parts by mass, and particularly preferably in the range of 1 to 10 parts by mass, per 100 parts by mass of the diene rubber (A).

[0032] Examples of the aforementioned process oils include naphthenic oils, paraffinic oils, and aromatic oils. These can be used individually or in combination of two or more.

[0033] Furthermore, when the process oil is used, its content is preferably in the range of 1 to 35 parts by mass, and particularly preferably in the range of 3 to 30 parts by mass, per 100 parts by mass of the diene rubber (A).

[0034] Furthermore, this vibration-damping rubber composition may contain carbon black as needed, to the extent that it does not affect the reduction of dynamic magnification by silica (B) and silane coupling agent (C). The carbon black mentioned above has a BET specific surface area of ​​10 to 150 m². 2 A BET specific surface area of ​​65-85 m² is preferred and more preferably has a specific surface area of ​​65-85 m². 2 The / g type is used. The BET specific surface area of ​​the carbon black can be measured, for example, by degassing the sample at 200°C for 15 minutes, and then using a mixed gas (N2: 70%, He: 30%) as the adsorbed gas, with a BET specific surface area measuring device (Microdata Corporation, 4232-II). From the viewpoint of reinforcing properties and durability, various grades of carbon black such as FEF, MAF, GPF, SRF, FT, and MT are used. These can be used individually or in combination of two or more. Among these, FEF grade carbon black is preferred from the above viewpoint.

[0035] When using the carbon black, its content is preferably in the range of 0.1 to 5 parts by mass, and particularly preferably in the range of 0.1 to 3 parts by mass, per 100 parts by mass of the diene rubber (A), from the viewpoint of fatigue resistance.

[0036] [Method for preparing vibration-damping rubber composition] Herein, this vibration-damping rubber composition can be prepared by using its essential components (A) to (E) in specific proportions, and, if necessary, using the other materials listed above, and mixing them using a kneader, Banbury mixer, open roll, twin-screw agitator, or other kneading equipment.

[0037] In particular, the kneading is preferably carried out by kneading the materials other than the vulcanizing agent and vulcanization accelerator using a Banbury mixer at 100 to 170°C for 3 to 10 minutes (preferably at 150 to 160°C for 3 to 5 minutes), then mixing in the vulcanizing agent and vulcanization accelerator, and kneading using an open roll at 30 to 80°C for 3 to 10 minutes (preferably at 30 to 60°C for 3 to 5 minutes). The vibration-damping rubber composition obtained in this manner exhibits excellent durability, can reduce dynamic magnification, and shows excellent scorch resistance in humid and hot environments.

[0038] Furthermore, this vibration-damping rubber composition becomes a vibration-damping rubber component (vulcanized body) by vulcanizing it at a high temperature (150-170°C) for 5-30 minutes.

[0039] Vibration-damping rubber members made from the vulcanized body of this vibration-damping rubber composition are preferably used as components for engine mounts, stabilizer bushings, suspension bushings, motor mounts, subframe mounts, and the like in automobiles and other vehicles. In addition to the above-mentioned uses, it can also be used as a vibration damping damper for computer hard disks, a vibration damping damper for general household appliances such as washing machines, and as a vibration damping device and seismic isolation device in the construction and housing sector, such as vibration damping walls and vibration damping dampers for buildings. [Examples]

[0040] Next, examples will be described together with comparative examples. However, the present invention is not limited to these examples.

[0041] [Examples 1-5, Comparative Examples 1-6] 100 parts by mass of natural rubber and silica (DEGUSSA ULTRASIL VN-3, BET specific surface area 200 m²) 2 50 parts by mass of / g (value measured according to the above method), 7 parts by mass of silane coupling agent (MOMENTIVE, NXT), 5 parts by mass of zinc oxide (Sakai Chemical Industry, zinc oxide type 2), 2 parts by mass of stearic acid (NOF Corporation, bead stearic acid sakura), 1 part by mass of antioxidant (Sumitomo Chemical, Antigen 6C), and 3 parts by mass of process oil (Nippon Sun Oil Co., Ltd., Sansen 410) were mixed using a Banbury mixer at 150°C for 5 minutes. The mixture obtained in this manner was then mixed with the vulcanization accelerators (CBS, MBS, MBTS) shown in Table 1 below in the proportions shown in the same table, and 2.5 parts by mass of a vulcanizing agent (sulfur, manufactured by Karuizawa Smelting Co., Ltd.) was added. The mixture was then kneaded at 60°C for 5 minutes using an open roll to prepare an anti-vibration rubber composition. For CBS (N-cyclohexyl-2-benzothiazolyl sulfenamide), ACCEL CZ manufactured by Kawaguchi Chemical Industry Co., Ltd. was used; for MBS, ACCEL NS manufactured by Kawaguchi Chemical Industry Co., Ltd. was used; and for MBTS, ACCEL DM manufactured by Kawaguchi Chemical Industry Co., Ltd. was used.

[0042] The vibration-damping rubber compositions of the examples and comparative examples obtained in this manner were used to evaluate their respective properties according to the following criteria. The results are shown in Table 1 below.

[0043] <Scorch resistance> Each vibration-damping rubber composition was stored for a predetermined number of days (4, 7, or 14 days) under conditions of 40°C, 20% RH (dry heat environment) or 40°C, 95% RH (moist heat environment). The scorch time (ST) at the test temperature (121°C) was measured for each vibration-damping rubber composition on day 0 of storage, and for each vibration-damping rubber composition after the predetermined number of days of storage, using a Mooney viscometer manufactured by Toyo Seiki Co., Ltd. Table 1 below shows the ST values ​​after a predetermined number of days of storage for each vibration-damping rubber composition, with the ST value on day 0 of storage set to 100 (reference). For samples stored at 40°C and 20%RH, samples were evaluated as having excellent scorch resistance if the ST value converted to an index was higher than that of Comparative Example 1 at each storage period, and the ST value converted to an index on the fourth day of storage was within 100±5. Samples that did not meet this "○" condition were evaluated as having poor scorch resistance and were evaluated as "×". Furthermore, for samples stored under a 40°C, 95%RH environment, samples where the ST value converted to an index was higher than that of Comparative Example 1 for each storage period were evaluated as having excellent scorch resistance ("○"), while samples that did not meet this "○" condition were evaluated as having poor scorch resistance ("×"). Furthermore, the reason for adding the requirement that "the ST value on the fourth day of storage, converted to an index, must be within 100±5" to the evaluation criteria for scorch resistance of samples stored at 40°C and 20%RH, in addition to whether or not there is superiority over Comparative Example 1 (which used CBS as a vulcanization accelerator), is to see whether or not it is possible to achieve the optimal vulcanization time after storage under storage conditions that are expected in a normal manufacturing environment (storage for 4 days at 40°C and 20%RH).

[0044] <Dynamic magnification> Each vibration-damping rubber composition was press-molded (vulcanized) at 150°C for 30 minutes to produce test pieces. The static spring constant (Ks) and dynamic spring constant (Kd100) at a frequency of 100 Hz of the test pieces were then measured in accordance with JIS K 6386. Based on these values, the dynamic magnification ratio (Kd100 / Ks) was calculated. Table 1 below shows the measured values ​​of dynamic magnification (Kd100 / Ks) in each example and comparative example, converted to exponential values, with the measured value of dynamic magnification (Kd100 / Ks) in Comparative Example 1 set to 100. Then, if the dynamic magnification value was within 100±5% of the dynamic magnification value of Comparative Example 1, it was evaluated as "○", and if it was not within 100±5% of the dynamic magnification value of Comparative Example 1, it was evaluated as "×". The reason for using these criteria is to determine whether the same level of low dynamic magnification as in Comparative Example 1 (which used CBS as a vulcanization accelerator) has been achieved.

[0045] [Table 1]

[0046] From the results in Table 1 above, the vibration-damping rubber composition of the example, in which the total content of MBS and MBTS was within the range specified in the present invention, and the mass ratio of MBS to MBTS was also within the range specified in the present invention, achieved a similar level of dynamic magnification reduction as Comparative Example 1 (which used CBS as a vulcanization accelerator), and showed superior scorch resistance compared to the rubber composition of Comparative Example 1. Moreover, in the evaluation of scorch resistance, the vibration-damping rubber composition of the example showed the advantageous characteristic of being able to exhibit the optimal vulcanization time after being stored under storage conditions that are expected in a normal manufacturing environment (stored for 4 days at 40°C and 20% RH).

[0047] In contrast, although the vibration-damping rubber compositions of Comparative Examples 2 to 6 use MBS and MBTS as vulcanization accelerators, the proportion of the vulcanization accelerators and other factors do not meet the requirements of the present invention. As a result, the simultaneous achievement of scorch resistance and low dynamic magnification required by the present invention is not achieved. Furthermore, although the vibration-damping rubber compositions of Comparative Examples 2, 3, and 6 show superiority over the rubber composition of Comparative Example 1 in terms of scorch resistance, they were unable to achieve the optimal vulcanization time when stored under storage conditions that are expected in a normal manufacturing environment, as described above. Therefore, the evaluation of scorch resistance under a 40°C, 20%RH environment was "×". [Industrial applicability]

[0048] The vibration-damping rubber composition of the present invention is preferably used as a material for components (vibration-damping rubber members) such as engine mounts, stabilizer bushings, suspension bushings, motor mounts, and subframe mounts used in automobiles and the like. In addition, it can also be used as a material for components (vibration-damping rubber members) of vibration damping devices and seismic isolation devices such as vibration damping walls and dampers for buildings in the construction and housing fields.

Claims

1. A vibration-damping rubber composition comprising a diene-based rubber composition containing the following (A) to (C) and also containing the following (D) and (E), The content of (B) is 5 to 100 parts by mass per 100 parts by mass of (A), and the content of (C) is 2 to 12 parts by mass per 100 parts by mass of (A). The total content of (D) and (E) is 1 to 5 parts by mass per 100 parts by mass of (A). A vibration-damping rubber composition in which the mass ratio of (D) to (E) is (D):(E) = 90:10 to 50:

50. (A) Diene-based rubber. (B) Silica. (C) Silane coupling agent. (D) N-oxydiethylene-2-benzothiazolyl sulfenamide. (E) di-2-benzothiazolyl disulfide.

2. The vibration-damping rubber composition according to claim 1, wherein the content of (B) is 10 to 80 parts by mass per 100 parts by mass of (A).

3. The vibration-damping rubber composition according to claim 1 or 2, wherein the content of (C) is 3 to 10 parts by mass per 100 parts by mass of (A).

4. The vibration-damping rubber composition according to any one of claims 1 to 3, wherein (C) is at least one selected from the group consisting of mercapto-silane coupling agents and sulfide-silane coupling agents.

5. A vibration-damping rubber member comprising a vulcanized body of the vibration-damping rubber composition according to any one of claims 1 to 4.

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