Anti-vibration rubber composition and Anti-vibration rubber member

Abstract

To provide an anti-vibration rubber composition and an anti-vibration rubber member capable of achieving both low dynamic magnification and durability.　Provided is an anti-vibration rubber composition containing the following components (A) to (C), in which the total amount of (B) and (C) is 20-70 mass parts per 100 mass parts of (A), and the ratio of (B) to the total amount of (B) and (C) is 50-90 mass%. The anti-vibration rubber member is obtained by using the anti-vibration rubber composition. (A) Diene rubber, (B) surface-active carbon black having an amount of hydrogen generated (Hc) per gram of carbon black when heated to 1980°C of 4500 ppm or more, (C) HAF grade carbon black

Description

Anti-vibration rubber composition and anti-vibration rubber member

[0001] The present invention relates to an anti-vibration rubber composition and an anti-vibration rubber member, and more particularly to an anti-vibration rubber composition and an anti-vibration rubber member suitable for anti-vibration rubber for vehicles such as automobiles.

[0002] Anti-vibration rubber compositions are used in automobiles to reduce vibration and noise. Such anti-vibration rubber compositions are required to have high rigidity and strength in their vulcanizates (anti-vibration rubber components) and to suppress vibration transmission, so that the dynamic magnification ratio [dynamic spring constant (Kd100) / static spring constant (Ks)] must be reduced (i.e., a low dynamic magnification ratio). Conventionally, measures to reduce the dynamic magnification ratio have been taken, for example, by using carbon black as a reinforcing agent in the anti-vibration rubber composition and controlling factors such as the amount of carbon black blended, particle size, and structure.

[0003] Patent No. 7037986

[0004] Meanwhile, automobile vibration-damping materials are also required to have durability, i.e., the ability to maintain vibration-damping performance and support rigidity even after long-term use. Carbon black with a high iodine adsorption capacity has the effect of improving durability, but the trade-off is the problem of a deterioration in dynamic magnification.

[0005] The problem to be solved by the present invention is to provide an anti-vibration rubber composition and an anti-vibration rubber member that can achieve both low dynamic magnification and durability.

[0006] In order to solve the above problems, the anti-vibration rubber composition of the present invention contains the following components (A) to (C), wherein the total amount of (B) and (C) is 20 parts by mass or more and 70 parts by mass or less per 100 parts by mass of (A), and the ratio of (B) to the total amount of (B) and (C) is 50% by mass or more and 90% by mass or less: (A) a diene rubber; (B) a surface-activated carbon black having a value (Hc) of 4500 ppm or more, calculated as the amount of hydrogen generated when heated to 1980°C per 1 g of carbon black; and (C) a HAF-grade carbon black.

[0007] The total amount of (B) and (C) is preferably 30 parts by mass or more and 50 parts by mass or less relative to 100 parts by mass of (A). The ratio of (B) to the total amount of (B) and (C) is preferably 60% by mass or more and 80% by mass or less. The iodine adsorption capacity of (C) is preferably 50 g / kg or more.

[0008] The anti-vibration rubber member according to the present invention is formed from a vulcanizate of the anti-vibration rubber composition according to the present invention.

[0009] The vibration-isolating rubber member according to the present invention can be suitably used for electric vehicles.

[0010] (1) The anti-vibration rubber composition according to the present invention contains the following components (A) to (C), wherein the total amount of (B) and (C) is 20 parts by mass or more and 70 parts by mass or less per 100 parts by mass of (A), and the ratio of (B) to the total amount of (B) and (C) is 50% by mass or more and 90% by mass or less: (A) a diene rubber; (B) a surface-activated carbon black having a value (Hc) of 4500 ppm or more, calculated as the amount of hydrogen generated when heated to 1980°C per 1 g of carbon black; and (C) a HAF-grade carbon black.

[0011] (2) In the above (1), the total amount of (B) and (C) may be 30 parts by mass or more and 50 parts by mass or less per 100 parts by mass of (A).

[0012] (3) In the above (1) or (2), the ratio of (B) to the total amount of (B) and (C) is preferably 60% by mass or more and 80% by mass or less.

[0013] (4) In any one of the above (1) to (3), the iodine adsorption capacity of (C) is preferably 50 g / kg or more.

[0014] (5) The anti-vibration rubber member according to the present invention is made of a vulcanized anti-vibration rubber composition according to any one of (1) to (4) above.

[0015] (6) In the above (5), the vibration-isolating rubber member according to the present invention may be used for an electric vehicle.

[0016] According to the vibration-proof rubber composition of the present invention, since it contains the above components (A) to (C) and the above components (B) and (C) are present in specific proportions, it is possible to achieve both a low dynamic magnification and durability.

[0017] When the total amount of (B) and (C) is 30 parts by mass or more and 50 parts by mass or less per 100 parts by mass of (A), the durability is improved and the dynamic magnification is easily reduced.

[0018] When the ratio of (B) to the total amount of (B) and (C) is 60% by mass or more and 80% by mass or less, the durability is improved and the dynamic magnification is easily reduced.

[0019] When the iodine adsorption amount of (C) is 50 g / kg or more, the durability is improved.

[0020] Furthermore, the anti-vibration rubber member according to the present invention is made of a vulcanizate of the anti-vibration rubber composition according to the present invention, and therefore can achieve both low dynamic magnification and durability.

[0021] The vibration-isolating rubber member according to the present invention can be suitably used for electric vehicles.

[0022] 1 is a distribution diagram of dynamic magnification (spring characteristics) versus hardness, consisting of data from Examples and Comparative Examples, and FIG. 2 is a distribution diagram of durability versus hardness, consisting of data from Examples and Comparative Examples.

[0023] The vibration-isolating rubber composition and vibration-isolating rubber member according to the present invention will be described in detail below.

[0024] The vibration-proof rubber composition according to the present invention (hereinafter sometimes simply referred to as the vibration-proof rubber composition) contains the following components (A) to (C), with (B) and (C) being present in specific proportions: (A) a diene rubber; (B) a surface-activated carbon black having a hydrogen content (Hc) of 4500 ppm or more per gram of carbon black when heated to 1980°C; and (C) a HAF-grade carbon black.

[0025] The diene rubber (A) is the main component of the rubber component of the vibration-proof rubber composition. The main component of the rubber component refers to a component that accounts for 50% by mass or more of the total rubber component of the vibration-proof rubber composition. The vibration-proof rubber composition is significantly affected by the properties of the diene rubber (A), which is the main component of the rubber component. Examples of the diene rubber (A) include natural rubber (NR), butadiene rubber (BR), styrene-butadiene rubber (SBR), chloroprene rubber (CR), isoprene rubber (IR), and acrylonitrile-butadiene rubber (NBR). These may be used alone or in combination as the diene rubber (A). Of these, natural rubber is preferably used from the viewpoint of achieving both strength, durability, and low dynamic magnification.

[0026] Surface-activated carbon black (B) has a high reinforcing effect and maintains spring characteristics without deteriorating the dynamic magnification of the vibration-proof rubber composition. As described above, surface-activated carbon black (B) has a hydrogen hemoglobin (Hc) of 4500 ppm or more, calculated as the amount of hydrogen generated per gram of carbon black when heated to 1980°C. Furthermore, a carbon black with an Hc of 5000 ppm or more is preferred because it provides superior surface activity. The amount of hydrogen is derived from hydrogen atoms of organic groups, such as hydroxyl groups and carboxyl groups, that are covalently bonded to carbon atoms in the carbon black.

[0027] The hydrogen amount is measured, for example, as follows. First, 20 mg of carbon black, which had previously been degassed and dried in a vacuum dryer at 125°C for 4 hours to remove adsorbed components from the carbon black, is placed in a tin capsule and thermally decomposed in a graphite crucible at 1980°C for 70 seconds using a high-sensitivity hydrogen analyzer (EMGA-621 manufactured by Horiba, Ltd., using a TCD detector). The generated gas is then passed through a high-temperature oxidizing agent, a room-temperature oxidizing agent, a carbon dioxide remover, and a desiccant at a constant flow rate (400 ml / min) of carrier gas (inert argon gas), and separated in a column. The hydrogen gas thus obtained is then quantified using a detector (thermal conductivity method).

[0028] The surface-active carbon black (B) may be used alone or in combination of two or more kinds, so long as it has the above-mentioned hydrogen content.

[0029] From the viewpoints of durability and low dynamic magnification, the surface-active carbon black (B) preferably has an iodine adsorption of 14 g / kg or more and 28 g / kg or less. The iodine adsorption of the carbon black is a value measured in accordance with JIS K 6217-1 (Method A). Furthermore, from the viewpoints of durability and low dynamic magnification, the surface-active carbon black (B) preferably has a DBP absorption of 118 ml / 100 g or more and 132 ml / 100 g or less. The DBP absorption of the carbon black is a value measured in accordance with JIS K 6217-4.

[0030] HAF grade carbon black (C) is a highly wear-resistant furnace carbon black, classified as an N300 grade according to ASTM D1765. From the viewpoints of durability and low dynamic magnification, HAF grade carbon black (C) preferably has an iodine adsorption of 50 g / kg or more, more preferably 50 g / kg or more and 100 g / kg or less, and even more preferably 60 g / kg or more and 90 g / kg or less. Furthermore, from the viewpoints of durability and low dynamic magnification, HAF grade carbon black (C) preferably has a DBP absorption of 50 ml / 100 g or more and 110 ml / 100 g or less.

[0031] HAF grade carbon black (C) is a carbon black with a high iodine adsorption capacity. Use of HAF grade carbon black (C) improves durability. On the other hand, the dynamic magnification ratio deteriorates. For this reason, using HAF grade carbon black (C) alone does not allow for both a low dynamic magnification ratio and durability. Surface-activated carbon black (B) has a high reinforcing effect and is effective in maintaining the spring characteristics without deteriorating the dynamic magnification ratio of the vibration-proof rubber composition. Furthermore, use of surface-activated carbon black (B) together with HAF grade carbon black (C) allows for both a low dynamic magnification ratio and durability.

[0032] The total amount of (B) and (C) is 20 parts by mass or more and 70 parts by mass or less per 100 parts by mass of (A). If the total amount of (B) and (C) is too small, the reinforcing effect is small, the rigidity (static spring constant) is low, and durability is low. If the total amount of (B) and (C) is too large, the rigidity is high but the durability is low. In addition, the dynamic magnification ratio deteriorates. By keeping the total amount of (B) and (C) within the above range, both a low dynamic magnification ratio and durability can be achieved. Furthermore, from the viewpoints of excellent durability improvement effect and ease of achieving a low dynamic magnification ratio, the total amount of (B) and (C) is more preferably 25 parts by mass or more and 60 parts by mass or less, and even more preferably 30 parts by mass or more and 50 parts by mass or less per 100 parts by mass of (A).

[0033] The proportion of (B) relative to the total amount of (B) and (C) is 50% by mass or more and 90% by mass or less. If the proportion of (B) is too low, the spring characteristics will be poor and the dynamic magnification will deteriorate. If the proportion of (B) is too high, durability will not be satisfactory. By keeping the proportion of (B) within the above range, both a low dynamic magnification and durability can be achieved. Furthermore, from the viewpoints of excellent durability improvement effects and ease of achieving a low dynamic magnification, the proportion of (B) relative to the total amount of (B) and (C) is more preferably 55% by mass or more and 85% by mass or less, and even more preferably 60% by mass or more and 80% by mass or less.

[0034] The content of (B) is preferably 10 parts by mass or more, more preferably 12.5 parts by mass or more, and even more preferably 15 parts by mass or more per 100 parts by mass of (A) from the viewpoint of facilitating a low dynamic magnification, etc. The content of (B) is preferably 63 parts by mass or less, more preferably 54 parts by mass or less, and even more preferably 45 parts by mass or less per 100 parts by mass of (A) from the viewpoint of ensuring the content of (C) and achieving an excellent effect of improving durability, etc.

[0035] The content of (C) is preferably 2 parts by mass or more, more preferably 2.5 parts by mass or more, and even more preferably 3 parts by mass or more per 100 parts by mass of (A) from the viewpoint of achieving an excellent effect of improving durability, etc. The content of (B) is preferably 35 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 25 parts by mass or less per 100 parts by mass of (A) from the viewpoint of ensuring the content of (B) and easily achieving a low dynamic magnification, etc.

[0036] The anti-vibration rubber composition according to the present invention may contain, in addition to the above components (A) to (C), additives such as vulcanizing agents, vulcanization accelerators, vulcanization aids, antioxidants, and process oils.

[0037] Examples of vulcanizing agents include sulfur (powdered sulfur, precipitated sulfur, insoluble sulfur) and sulfur-containing compounds such as alkylphenol disulfides. These may be used alone or in combination of two or more. Sulfur is preferred.

[0038] The content of the vulcanizing agent is preferably in the range of 0.1 to 10 parts by mass, particularly preferably 0.3 to 5 parts by mass, per 100 parts by mass of the diene rubber (A). If the content of the vulcanizing agent is too low, crosslinking reactivity tends to deteriorate. If the content of the vulcanizing agent is too high, rubber physical properties (breaking strength, breaking elongation) tend to deteriorate.

[0039] When sulfur is used as a vulcanizing agent, the sulfur content is preferably within a range of 1 to 2.5 parts by mass per 100 parts by mass of the diene rubber (A). More preferably, it is within a range of 1.5 to 2 parts by mass. By having a sulfur content of 1 part by mass or more, crosslink density can be ensured and a decrease in static spring constant can be suppressed. Furthermore, by having a sulfur content of 2.5 parts by mass or less, excellent heat resistance can be achieved.

[0040] Examples of the vulcanization accelerator include thiuram-based, sulfenamide-based, guanidine-based, thiazole-based, aldehyde ammonia-based, aldehyde amine-based, and thiourea-based vulcanization accelerators. These may be used alone or in combination of two or more. Among these, a combination of a thiuram-based vulcanization accelerator and at least one vulcanization accelerator selected from the sulfenamide-based, guanidine-based, and thiazole-based vulcanization accelerators is preferred because it provides excellent compression set.

[0041] The content of the vulcanization accelerator is preferably in the range of 0.1 to 10 parts by mass, particularly preferably in the range of 0.3 to 5 parts by mass, per 100 parts by mass of the diene rubber (A).

[0042] Examples of thiuram vulcanization accelerators include tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide (TETD), tetrabutylthiuram disulfide (TBTD), tetrakis(2-ethylhexyl)thiuram disulfide (TOT), and tetrabenzylthiuram disulfide (TBzTD).

[0043] Examples of sulfenamide vulcanization accelerators include N-oxydiethylene-2-benzothiazolylsulfenamide (NOBS), N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), N-t-butyl-2-benzothiazolesulfenamide (BBS), N,N'-dicyclohexyl-2-benzothiazolesulfenamide, etc. These may be used alone or in combination of two or more.

[0044] Examples of the guanidine vulcanization accelerator include N,N'-diphenylthiourea, trimethylthiourea, N,N'-diethylthiourea, N,N'-dibutylthiourea, etc. These may be used alone or in combination of two or more.

[0045] Examples of thiazole vulcanization accelerators include dibenzothiazyl disulfide (MBTS), 2-mercaptobenzothiazole (MBT), 2-mercaptobenzothiazole sodium salt (NaMBT), and 2-mercaptobenzothiazole zinc salt (ZnMBT). These may be used alone or in combination of two or more. Among these, dibenzothiazyl disulfide (MBTS) and 2-mercaptobenzothiazole (MBT) are preferred because of their particularly excellent crosslinking reactivity.

[0046] Examples of the vulcanization aid include zinc oxide (ZnO), stearic acid, magnesium oxide, etc. These may be used alone or in combination of two or more.

[0047] The content of the vulcanization aid is preferably in the range of 0.1 to 10 parts by mass, particularly preferably in the range of 0.3 to 7 parts by mass, per 100 parts by mass of the diene rubber (A).

[0048] Examples of the antiaging agent include amine-based antiaging agents, imidazole-based antiaging agents, carbamate-based antiaging agents, phenol-based antiaging agents, and quinoline-based antiaging agents. These may be used alone or in combination of two or more. As the antiaging agent, it is preferable to use an amine-based antiaging agent and an imidazole-based antiaging agent in combination.

[0049] The content of the antioxidant is preferably in the range of 0.5 to 15 parts by mass, particularly preferably in the range of 1 to 10 parts by mass, per 100 parts by mass of the diene rubber (A).

[0050] Examples of amine-based antiaging agents include those having a diphenylamine skeleton, those having a phenylenediamine skeleton, and those having a dihydroquinoline skeleton. Specific examples include 2,2,4-trimethyl-1,2-dihydroquinoline polymers, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, 4,4'-bis(4-α,α-dimethylbenzyl)diphenylamine, and N,N'-di-β-naphthyl-p-phenylenediamine.

[0051] The blending ratio of the amine-based antioxidant is preferably in the range of 1 to 10 parts by mass, particularly preferably in the range of 2 to 5 parts by mass, per 100 parts by mass of the diene rubber (A).

[0052] Examples of process oils include naphthenic oils, paraffinic oils, aromatic oils, etc. These may be used alone or in combination of two or more.

[0053] The content of the process oil is preferably in the range of 1 to 35 parts by mass, particularly preferably in the range of 3 to 30 parts by mass, per 100 parts by mass of the diene rubber (A).

[0054] The vibration-proof rubber composition according to the present invention can be prepared by kneading the components (A) to (C) and other materials added as necessary using a kneading machine such as a kneader, a Banbury mixer, an open roll, or a twin-screw mixer.

[0055] The anti-vibration rubber composition according to the present invention becomes an anti-vibration rubber member (vulcanizate) by vulcanizing it at a high temperature (150 to 170°C) for 5 to 30 minutes. Anti-vibration rubber members made from the vulcanizate of the anti-vibration rubber composition according to the present invention can be advantageously used in automotive anti-vibration rubber applications such as motor mounts, suspension bushings, and subframe mounts for engine vehicles and electric vehicles powered by electric motors (including electric vehicles (EVs), fuel cell vehicles (FCVs), plug-in hybrid vehicles (PHVs), hybrid vehicles (HVs), etc.).

[0056] According to the vibration-damping rubber composition of the present invention having the above-mentioned configuration, the diene rubber (A) is blended with the surface-active carbon black (B) and the HAF-grade carbon black (C), and since the above (B) and (C) are blended in a specific ratio, it is possible to achieve both a low dynamic magnification and durability.

[0057] In view of suitability for electric vehicles, the anti-vibration rubber composition according to the present invention preferably has a static spring constant Ks of 300 N / mm or more and 1000 N / mm or less, and more preferably 400 N / mm or more and 750 N / mm or less. By configuring the anti-vibration rubber composition according to the present invention as described above, the static spring constant Ks can be set within the above range.

[0058] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the invention.

[0059] The present invention will be described in detail below using examples and comparative examples.

[0060] The materials used are as follows: <Component A> Natural rubber (NR) <Component B> Surface-activated carbon black (CB): "SPHERON 5200" manufactured by Cabot Japan (Hc: 5200 ppm, iodine adsorption 24 g / kg, DBP absorption 124 ml / 100 g) <Component C> HAF-grade carbon black (CB) <1>: "VULCAN 3D" manufactured by Cabot Japan (iodine adsorption 81 g / kg, DBP absorption 101 ml / 100 g) HAF-grade carbon black (CB) <2>: "SEAST 300" manufactured by Tokai Carbon (iodine adsorption 86 g / kg, DBP absorption 75 ml / 100 g) <Others>・Surface-inactivated carbon black (CB): "Seast SO" (FEF grade) manufactured by Tokai Carbon, iodine adsorption capacity 44 g / kg, DBP absorption capacity 115 ml / 100 g) ・Zinc oxide: "Zinc oxide type 2" manufactured by Sakai Chemical Industry Co., Ltd. ・Stearic acid: "Lunacc S30" manufactured by Kao ・Process oil: "Sansen 4130" manufactured by Nippon San Oil Co., Ltd. ・Amine-based anti-aging agent <1>: "Ozonone 6C" manufactured by Seiko Chemical Co., Ltd. ・Amine-based anti-aging agent <2>: "Nonflex RD" manufactured by Seiko Chemical Co., Ltd. ・Vulcanization accelerator <1>: "Noccela CZ" manufactured by Ouchi Shinko Chemical Co., Ltd. ・Vulcanization accelerator <2>: "Noccela TBT" manufactured by Ouchi Shinko Chemical Co., Ltd. ・Sulfur (vulcanizing agent)

[0061] (Examples 1 to 5, Comparative Examples 1 to 5) Each material was blended in the proportions shown in the table, and then kneaded using an internal mixer (Banbury type) or a roll to prepare a rubber composition. The properties of the prepared rubber compositions were measured and evaluated according to the following methods.

[0062] [Hardness] Each rubber composition was press-molded and vulcanized at 150°C for 20 minutes to prepare a rubber sheet having a thickness of 2 mm. JIS No. 5 dumbbells were punched out from the rubber sheet, and the hardness (JIS A) was measured using these dumbbells in accordance with JIS K 6251. In the table, each value is expressed as an index, with the hardness of Example 1 being set at 100.

[0063] [Static Spring Constant (Ks)] Using each rubber composition, a disc-shaped metal piece (60 mm diameter, 6 mm thickness) was pressed onto the top and bottom surfaces of a rubber piece (50 mm diameter, 25 mm height) under vulcanization conditions of 170°C x 30 minutes to prepare a rubber test piece. Next, the rubber test piece was compressed 7 mm in the cylindrical axial direction, and the loads at deflections of 1.5 mm and 3.5 mm were read from the load-deflection curve of the second forward movement to calculate the static spring constant (Ks (N / mm)). In the table, the static spring constant (Ks) of Example 1 was set to 100, and each value was expressed as an index.

[0064] [Dynamic spring constant (Kd100)] The rubber test piece was compressed 2.5 mm in the cylindrical axial direction, and a constant displacement harmonic compression vibration of 100 Hz and amplitude 0.05 mm was applied from below around the 2.5 mm compression position, and the dynamic load was detected by a load cell above, and the dynamic spring constant (Kd100 (N / mm)) was calculated and measured in accordance with JIS K 6394. In the table, the dynamic spring constant (Kd100) of Example 1 was set to 100, and each value was expressed as an index.

[0065] [Dynamic magnification (Kd100 / Ks)] The dynamic magnification was calculated as the value of dynamic spring constant (Kd100) / static spring constant (Ks). In the table, the dynamic magnification (Kd100 / Ks) of Example 1 was set to 100, and each value was converted into an index.

[0066] [Durability] Each rubber composition was press-molded (vulcanized) at 150°C for 30 minutes to prepare a rubber sheet having a thickness of 2 mm. JIS No. 3 dumbbells were punched out from the rubber sheet, and these dumbbells were subjected to a stretch fatigue test in accordance with JIS K 6260 to measure the number of cycles of durability. In the table, each value is expressed as an index, with the number of cycles of durability in Example 1 being set at 100.

[0067] [Evaluation of spring characteristics relative to hardness] Data from each example and comparative example was plotted with hardness (index) on the horizontal axis and dynamic magnification (index) on the vertical axis to create a distribution diagram as shown in Figure 1. As shown in Figure 1, it can be seen that the spring characteristics relative to hardness generally tend to rise to the right. Using an approximate straight line as a reference, in Figure 1, values ​​below this line (the dotted line rising to the right in Figure 1) were marked with a "◯" and values ​​above this line were marked with an "X".

[0068] [Evaluation of durability relative to hardness] Data from each example and comparative example were plotted with hardness (index) on the horizontal axis and endurance cycles (index) on the vertical axis to create a distribution diagram as shown in Figure 2. As shown in Figure 2, it can be seen that the endurance cycles relative to hardness generally tend to decline to the right. Using an approximate straight line as a reference, values ​​located above this line (the dotted line sloping downward to the right in Figure 2) in Figure 2 were marked with a "◯" and values ​​located below this line were marked with a "X".

[0069] [Overall Evaluation] When both the spring characteristics relative to hardness and the durability relative to hardness were "good", the evaluation was "good", and when either one was "bad", the evaluation was "bad".

[0070]

[0071] In Comparative Example 1, surface-activated carbon black (B) is not used for the diene rubber (A), and HAF-grade carbon black (C) is used alone. Comparative Example 1 exhibits poor dynamic magnification ratio relative to hardness, resulting in poor spring properties. Comparative Example 2 exhibits poor durability, and surface-activated carbon black (B) is not used for the diene rubber (A), and instead FEF-grade carbon black is used. That is, FEF-grade carbon black with a low iodine adsorption capacity and HAF-grade carbon black (C) with a high iodine adsorption capacity are used in combination. Comparative Example 2 exhibits poor durability. Comparative Example 3 exhibits poor durability, and surface-activated carbon black (B) is not used for the diene rubber (A), and only surface-activated carbon black (B) is used. Comparative Example 4 exhibits poor dynamic magnification ratio relative to hardness, resulting in poor spring properties. In Comparative Example 5, the diene rubber (A) is used in combination with surface-activated carbon black (B) and HAF-grade carbon black (C), but the amount of surface-activated carbon black (B) used is too small. In Comparative Example 5, the dynamic magnification ratio relative to hardness is poor, and the spring characteristics are poor.

[0072] On the other hand, in the examples, diene rubber (A) is blended with surface-activated carbon black (B) and HAF-grade carbon black (C), with (B) and (C) being blended in specific proportions. The examples have a good dynamic magnification ratio relative to hardness and excellent spring properties. They also have excellent durability.

[0073] From the above, according to the Examples and Comparative Examples, it is clear that by blending surface-active carbon black (B) and HAF-grade carbon black (C) with diene rubber (A) and by using specific ratios of (B) and (C), it is possible to achieve both low dynamic magnification and durability.

[0074] Although the embodiments and examples of the present invention have been described above, the present invention is not limited to the above embodiments and examples, and various modifications are possible within the scope of the invention.

Claims

1. An anti-vibration rubber composition comprising the following components (A) to (C), the total amount of (B) and (C) being 20 to 70 parts by mass per 100 parts by mass of (A), and the ratio of (B) to the total amount of (B) and (C) being 50 to 90% by mass: (A) a diene rubber, (B) a surface-active carbon black having a hydrogen amount generated when heated to 1980°C of 4500 ppm or more (Hc) per gram of carbon black, and (C) a HAF-class carbon black.

2. The vibration-proof rubber composition according to claim 1, wherein the total amount of (B) and (C) is 30 parts by mass or more and 50 parts by mass or less per 100 parts by mass of (A).

3. The vibration-proof rubber composition according to claim 1 or 2, wherein the ratio of (B) to the total amount of (B) and (C) is 60 mass % or more and 80 mass % or less.

4. The anti-vibration rubber composition according to any one of claims 1 to 3, wherein the iodine adsorption amount of (C) is 50 g / kg or more.

5. An anti-vibration rubber member comprising a vulcanizate of the anti-vibration rubber composition according to any one of claims 1 to 4.

6. The anti-vibration rubber member according to claim 5, which is for use in an electric vehicle.

Images