Anti-vibration rubber composition and anti-vibration rubber member

Abstract

Provided are an anti-vibration rubber composition and an anti-vibration rubber member which can achieve both low dynamic magnification and durability. The present invention relates to an anti-vibration rubber composition containing the following components (A)-(C), the total amount of (B) and (C) being 20-70 parts by mass (inclusive) per 100 parts by mass of (A), and the ratio of (B) to the total amount of (B) and (C) being 50-90% by mass (inclusive). In addition, the anti-vibration rubber member uses the anti-vibration rubber composition. (A) A diene rubber (B) A surface activated carbon black in which the amount of hydrogen generated when heated to 1980 DEG C is 4500 ppm or more in terms of the value (Hc) per 1 g of carbon black (C) A HAF grade carbon black.

Description

TECHNICAL FIELD

[0001] The present application relates to a vibration-proof rubber composition and a vibration-proof rubber member, and more particularly to a vibration-proof rubber composition and a vibration-proof rubber member suitable for a vibration-proof rubber for a vehicle such as an automobile. BACKGROUND

[0002] In an automobile, a vibration-proof rubber composition is used for the purpose of reducing vibration and noise. For such a vibration-proof rubber composition, a vulcanized body (vibration-proof rubber member) thereof needs to have high rigidity, high strength, and suppress transmission of vibration, and thus it is required to reduce the value of dynamic modulus [dynamic stiffness (Kd100) / static stiffness (Ks)] (low dynamic modulus). In the past, as a countermeasure for this low dynamic modulus, for example, carbon black is used as a reinforcing agent in the vibration-proof rubber composition, and factors such as a compounding amount, a particle diameter, a structure, and the like of the carbon black are controlled.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT DOCUMENTS

[0005] Patent Document 1: Japanese Patent No. 7037986 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] However, for a vibration-proof member for an automobile, durability, that is, a performance in which a vibration-proof performance and a supporting rigidity are not impaired even if used for a long time, is also required. Carbon black having a large iodine adsorption amount has an effect of improving durability, but on the contrary, there is a problem in which dynamic modulus is deteriorated.

[0008] The present application relates to a vibration-proof rubber composition and a vibration-proof rubber member, and more particularly to a vibration-proof rubber composition and a vibration-proof rubber member suitable for a vehicle such as an automobile.

[0009] SOLUTION TO PROBLEM

[0010] The vibration-proof rubber composition of the present application for solving the above problem contains the following (A) to (C) components, and the total amount of the (B) and the (C) is 20 parts by mass or more and 70 parts by mass or less with respect to 100 parts by mass of the (A), and the proportion of the (B) with respect to the total amount of the (B) and the (C) is 50% by mass or more and 90% by mass or less,

[0011] (A) diene rubber

[0012] (B) surface active carbon black in which the amount of hydrogen generated when heated to 1980°C is 4500 ppm or more per 1 g of the carbon black (Hc)

[0013] (C) HAF grade carbon black.

[0014] The total amount of the (B) and the (C) can be 30 parts by mass or more and 50 parts by mass or less relative to 100 parts by mass of the (A). The proportion of the (B) relative to the total amount of the (B) and the (C) can be 60 mass% or more and 80 mass% or less. The iodine adsorption amount of the (C) can be 50 g / kg or more.

[0015] Further, the vibration-proof rubber member of the present application is composed of a vulcanizate of the vibration-proof rubber composition of the present application.

[0016] The vibration-proof rubber member of the present application can be suitably used for electric cars.

[0017] (1) The vibration-proof rubber composition of the present application contains the following (A) to (C) components, the total amount of the (B) and the (C) is 20 parts by mass or more and 70 parts by mass or less relative to 100 parts by mass of the (A), and the proportion of the (B) relative to the total amount of the (B) and the (C) is 50 mass% or more and 90 mass% or less,

[0018] (A) diene rubber

[0019] (B) surface active carbon black having a value (Hc) of 4500 ppm or more per 1 g of carbon black when the amount of hydrogen generated by heating to 1980°C is converted

[0020] (C) HAF grade carbon black.

[0021] (2) In the above (1), the total amount of the (B) and the (C) can be 30 parts by mass or more and 50 parts by mass or less relative to 100 parts by mass of the (A).

[0022] (3) In the above (1) or (2), the proportion of the (B) relative to the total amount of the (B) and the (C) can be 60 mass% or more and 80 mass% or less.

[0023] (4) In any one of the above (1) to (3), the iodine adsorption amount of the (C) can be 50 g / kg or more.

[0024] (5) The vibration-proof rubber member of the present application is composed of a vulcanizate of the vibration-proof rubber composition of any one of the above (1) to (4).

[0025] (6) In the above (5), the vibration-proof rubber member of the present application can be used for electric cars.

[0026] Effects of the Invention

[0027] The vibration-proof rubber composition according to the present application, since it contains the above (A) to (C) components, the above (B) and the above (C) are in a specific proportion, and thus it is possible to achieve both low dynamic modulus and durability.

[0028] Here, if the total amount of the (B) and the (C) is 30 parts by mass or more and 50 parts by mass or less relative to 100 parts by mass of the (A), the effect of improving durability is excellent. In addition, it is easy to become a low dynamic ratio.

[0029] Further, if the proportion of the (B) relative to the total amount of the (B) and the (C) is 60% by mass or more and 80% by mass or less, the effect of improving durability is excellent. In addition, it is easy to become a low dynamic ratio.

[0030] Further, if the iodine adsorption amount of the (C) is 50 g / kg or more, the effect of improving durability is excellent.

[0031] Further, the antivibration rubber member of the present application is composed of a vulcanizate of the antivibration rubber composition of the present application, and thus low dynamic ratio and durability can be balanced.

[0032] Further, the antivibration rubber member of the present application can be suitably used for electric vehicles. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is a graph showing the distribution of dynamic ratio (spring characteristic) with respect to hardness, composed of data of examples and comparative examples.

[0034] Figure 2 is a graph showing the distribution of durability with respect to hardness, composed of data of examples and comparative examples. DETAILED DESCRIPTION

[0035] Hereinafter, the antivibration rubber composition and the antivibration rubber member of the present application will be described in detail.

[0036] The antivibration rubber composition of the present application (hereinafter, sometimes simply referred to as the antivibration rubber composition) contains the following (A) to (C) components, and the (B) and the (C) are in a specific ratio,

[0037] (A) diene rubber

[0038] (B) surface active carbon black having a value (Hc) of 4500 ppm or more when the amount of hydrogen generated by heating to 1980°C is converted to per 1 g of carbon black

[0039] (C) HAF grade carbon black.

[0040] The diene rubber (A) is a main component of the rubber component of the vibration isolating rubber composition. The main component of the rubber component refers to a component that accounts for 50% by mass or more of the entire rubber component of the vibration isolating rubber composition. The vibration isolating rubber composition is greatly influenced by the properties of the diene rubber (A) as the main component of the rubber component. As the diene rubber (A), natural rubber (NR), butadiene rubber (BR), styrene-butadiene rubber (SBR), chloroprene rubber (CR), isoprene rubber (IR), acrylonitrile-butadiene rubber (NBR), and the like can be given. These can be used alone or in combination of two or more as the diene rubber (A). Among them, from the viewpoint of giving consideration to strength, durability, and low dynamic modulus, it is preferable to use natural rubber.

[0041] The surface active carbon black (B) has a high reinforcing effect and has an effect of maintaining the spring properties without deteriorating the dynamic modulus of the vibration isolating rubber composition. As described above, the surface active carbon black (B) has a hydrogen amount generated when heated to 1980°C of 4500 ppm or more per 1 g of carbon black (Hc). Further, if the above Hc is 5000 ppm or more, the surface activity is more excellent, and thus it is preferable. Note that the above hydrogen amount is derived from hydrogen atoms of organic groups that are covalently bonded to carbon atoms of the carbon black, such as hydroxyl groups and carboxyl groups.

[0042] The above hydrogen amount is measured, for example, as follows. That is, first, in order to remove the adsorbed components of the carbon black, 20 mg of the carbon black that has been previously degassed and dried at 125°C for 4 hours using a vacuum drier is put into a tin capsule, and using a high-sensitivity hydrogen analyzer (EMGA-621 manufactured by HORIBA, Ltd., using a TCD detector), it is heat-decomposed in a graphite crucible at 1980°C for 70 seconds. Then, the generated gas is passed through a high-temperature oxidizer, a normal-temperature oxidizer, a carbon dioxide removal agent, and a drying agent using a column to separate. Then, the hydrogen gas thus obtained is quantified using a detector (thermal conductivity method).

[0043] The surface active carbon black (B) can be used alone as long as it has the above hydrogen amount, or two or more kinds can be used in combination.

[0044] From the viewpoint of durability and low dynamic modulus, the iodine adsorption amount of the surface active carbon black (B) is preferably 14 g / kg or more and 28 g / kg or less. The iodine adsorption amount of the carbon black is a value measured in accordance with JIS K 6217-1 (A method). In addition, from the viewpoint of durability and low dynamic modulus, the surface active carbon black (B) preferably has a DBP absorption amount of 118 ml / 100 g or more and 132 ml / 100 g or less. The DBP absorption amount of the carbon black is a value measured in accordance with JIS K 6217-4.

[0045] The HAF-grade carbon black (C) is a carbon black for a high wear resistance furnace, and is a carbon black classified into the N300 series according to the ASTM D1765 type classification. From the viewpoint of durability and low dynamic modulus, the iodine adsorption amount of the HAF-grade carbon black (C) is preferably 50 g / kg or more. More preferably, it is 50 g / kg or more and 100 g / kg or less, and further preferably, it is 60 g / kg or more and 90 g / kg or less. In addition, from the viewpoint of durability and low dynamic modulus, the HAF-grade carbon black (C) preferably has a DBP absorption amount of 50 ml / 100 g or more and 110 ml / 100 g or less.

[0046] The HAF-grade carbon black (C) is a carbon black having a large iodine adsorption amount. By using the HAF-grade carbon black (C), durability is improved. On the other hand, the dynamic modulus deteriorates. Therefore, when the HAF-grade carbon black (C) is used alone, it is not possible to balance low dynamic modulus and durability. The surface-active carbon black (B) has a high reinforcing effect, and has an effect of maintaining the spring characteristics without deteriorating the dynamic modulus of the vibration-proof rubber composition. Furthermore, by using the surface-active carbon black (B) together with the HAF-grade carbon black (C), it is possible to balance low dynamic modulus and durability.

[0047] The total amount of (B) and (C) is 20 parts by mass or more and 70 parts by mass or less with respect to 100 parts by mass of (A). When the total amount of (B) and (C) is too small, the reinforcing effect is small, the rigidity (static stiffness) is low, and the durability is low. When the total amount of (B) and (C) is too large, the rigidity becomes high, but the durability becomes low. In addition, the dynamic modulus deteriorates. By making the total amount of (B) and (C) within the above range, it is possible to balance low dynamic modulus and durability. Furthermore, from the viewpoint that the effect of improving durability is excellent and it is easy to become a low dynamic modulus, the total amount of (B) and (C) is more preferably 25 parts by mass or more and 60 parts by mass or less, and further preferably, it is 30 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of (A).

[0048] The proportion of (B) with respect to the total amount of (B) and (C) is 50% by mass or more and 90% by mass or less. When the proportion of (B) is too low, the spring characteristics are poor, and the dynamic modulus deteriorates. When the proportion of (B) is too high, it is not possible to satisfy the durability. By making the proportion of (B) within the above range, it is possible to balance low dynamic modulus and durability. Furthermore, from the viewpoint that the effect of improving durability is excellent and it is easy to become a low dynamic modulus, the proportion of (B) with respect to the total amount of (B) and (C) is more preferably 55% by mass or more and 85% by mass or less, and further preferably, it is 60% by mass or more and 80% by mass or less.

[0049] Furthermore, from the viewpoint that it may easily result in a low boost rate, 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, relative to 100 parts by mass of (A). Additionally, from the viewpoint of ensuring the content of (C) and excellent durability improvement, 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, relative to 100 parts by mass of (A).

[0050] Furthermore, from the viewpoint of excellent durability improvement, 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, relative to 100 parts by mass of (A). Additionally, from the viewpoint of ensuring the content of (B) and easily achieving a low dynamic range, the content of (C) 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, relative to 100 parts by mass of (A).

[0051] In the vibration-damping rubber composition of the present invention, additives may also be appropriately included together with the components (A) to (C) above. Examples of additives include vulcanizing agents, vulcanization accelerators, vulcanization aids, anti-aging agents, and process oils.

[0052] Examples of sulfur-containing compounds that can be used as vulcanizing agents include sulfur (powdered sulfur, precipitated sulfur, insoluble sulfur), alkylphenol disulfides, etc. They can be used alone or in combination of two or more. Sulfur is more preferred.

[0053] The content of the vulcanizing agent relative to 100 parts by weight of diene rubber (A) is preferably in the range of 0.1 to 10 parts by weight, and particularly preferably in the range of 0.3 to 5 parts by weight. When the content of the vulcanizing agent is too low, a tendency for poor crosslinking reactivity is observed. When the content of the vulcanizing agent is too high, a tendency for a decrease in rubber properties (breaking strength, elongation at break) is observed.

[0054] When sulfur is used as a vulcanizing agent, the sulfur content is preferably in the range of 1 to 2.5 parts by mass relative to 100 parts by mass of diene rubber (A). More preferably, it is in the range of 1.5 to 2 parts by mass. By making the sulfur content 1 part by mass or more, the crosslinking density can be ensured and the decrease in static stiffness can be suppressed. In addition, by making the sulfur content 2.5 parts by mass or less, the heat resistance becomes excellent.

[0055] Examples of vulcanization accelerators include thiuram-based, sulfenamide-based, guanidine-based, thiazole-based, aldehyde-amine-based, and thiourea-based vulcanization accelerators. These can be used alone or in combination of two or more. From the perspective of excellent compression set, it is preferable to combine a thiuram-based vulcanization accelerator with at least one vulcanization accelerator selected from sulfenamide-based, guanidine-based, and thiazole-based accelerators.

[0056] The content of vulcanization accelerator is preferably in the range of 0.1 to 10 parts by weight relative to 100 parts by weight of diene rubber (A), and particularly preferably in the range of 0.3 to 5 parts by weight.

[0057] Examples of thiuram-based vulcanization accelerators include tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide (TETD), tetrabutylthiuram disulfide (TBTD), tetra(2-ethylhexyl)thiuram disulfide (TOT), and tetrabenzylthiuram disulfide (TBzTD).

[0058] Examples of sulfenamide-based vulcanization accelerators include N-oxodiethyl-2-benzothiazole sulfenamide (NOBS), N-cyclohexyl-2-benzothiazole sulfenamide (CBS), N-tert-butyl-2-benzothiazole sulfenamide (BBS), and N,N'-dicyclohexyl-2-benzothiazole sulfenamide. They can be used alone or in combination of two or more.

[0059] Examples of guanidine-based vulcanization accelerators include N,N'-diphenylthiourea, trimethylthiourea, N,N'-diethylthiourea, and N,N'-dibutylthiourea. They can be used alone or in combination of two or more.

[0060] Examples of thiazole-based vulcanization accelerators include dibenzothiazole disulfide (MBTS), 2-mercaptobenzothiazole (MBT), sodium 2-mercaptobenzothiazole (NaMBT), and zinc 2-mercaptobenzothiazole (ZnMBT). These can be used alone or in combination of two or more. Of particular preference, dibenzothiazole disulfide (MBTS) and 2-mercaptobenzothiazole (MBT) are preferred, especially considering their excellent crosslinking reactivity.

[0061] Examples of vulcanizing aids include zinc oxide (ZnO), stearic acid, and magnesium oxide. They can be used alone or in combination of two or more.

[0062] The content of vulcanizing aid is preferably in the range of 0.1 to 10 parts by weight relative to 100 parts by weight of diene rubber (A), and particularly preferably in the range of 0.3 to 7 parts by weight.

[0063] Examples of anti-aging agents include amine-based anti-aging agents, imidazole-based anti-aging agents, carbamate-based anti-aging agents, phenol-based anti-aging agents, and quinoline-based anti-aging agents. These can be used individually or in combination. Amine-based and imidazole-based anti-aging agents can also be used together.

[0064] The content of the anti-aging agent is preferably in the range of 0.5 to 15 parts by weight relative to 100 parts by weight of diene rubber (A), and particularly preferably in the range of 1 to 10 parts by weight.

[0065] Examples of amine-based anti-aging agents include those with a diphenylamine backbone, those with a phenylenediamine backbone, and those with a dihydroquinoline backbone. Specific examples include polymers of 2,2,4-trimethyl-1,2-dihydroquinoline, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, 4,4'-bis(4-α,α-dimethylbenzyl)diphenylamine, and N,N'-di-β-naphthyl-p-phenylenediamine.

[0066] The preferred blending ratio of the amine anti-aging agent is 1 to 10 parts by weight relative to 100 parts by weight of diene rubber (A), and particularly preferably 2 to 5 parts by weight.

[0067] Process oils include naphthenic oils, paraffinic oils, and aromatic oils. They can be used alone or in combination of two or more.

[0068] The content of process oil is preferably in the range of 1 to 35 parts by weight relative to 100 parts by weight of diene rubber (A), and particularly preferably in the range of 3 to 30 parts by weight.

[0069] The vibration-damping rubber composition of the present invention can be prepared by mixing the components (A) to (C) and other materials as needed using a kneader, Banbury mixer, open mill, twin-screw mixer, or other mixing mill.

[0070] The anti-vibration rubber composition of the present invention is vulcanized at a high temperature (150~170°C) for 5~30 minutes to become an anti-vibration rubber component (vulcanized body). Furthermore, the anti-vibration rubber component composed of the vulcanized body of the anti-vibration rubber composition of the present invention can be advantageously used as an anti-vibration rubber for engines, motor vehicles, electric vehicles powered by electric motors (including fuel cell vehicles (FCVs), plug-in hybrid vehicles (PHVs), hybrid vehicles (HVs), etc., in addition to electric vehicles (EVs)).

[0071] The vibration-damping rubber composition of the present invention, constructed according to the above, can achieve both low dynamic range and durability by mixing surface-activated carbon black (B) and HAF-grade carbon black (C) with respect to diene rubber (A) in a specific ratio.

[0072] In the anti-vibration rubber composition of the present invention, from the viewpoint of suitability for use in electric vehicles, etc., the static stiffness Ks is preferably 300 N / mm or more and 1000 N / mm or less. More preferably, it is 400 N / mm or more and 750 N / mm or less. By adopting the above-described constitution, the anti-vibration rubber composition of the present invention can set the static stiffness Ks within the above range.

[0073] The embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments, and various changes can be made without departing from the gist of the present invention.

[0074] Examples

[0075] Hereinafter, the present invention will be described in detail using examples and comparative examples.

[0076] The materials used are as follows.

[0077] <Component A>

[0078] · Natural rubber (NR)

[0079] <Component B>

[0080] · Surface active carbon black (CB): "SPHERON5200" manufactured by Cabot Japan (Hc: 5200 ppm, iodine adsorption amount 24 g / kg, DBP absorption amount 124 ml / 100 g)

[0081] <Component C>

[0082] · HAF grade carbon black (CB)<1>: "VULCAN 3D" manufactured by Cabot Japan, iodine adsorption amount 81 g / kg, DBP absorption amount 101 ml / 100 g)

[0083] · HAF grade carbon black (CB)<2>: "SEAST300" manufactured by TOKAI CARBON CO., LTD., iodine adsorption amount 86 g / kg, DBP absorption amount 75 ml / 100 g)

[0084] <Others>

[0085] · Surface non-active carbon black (CB): "SEASTSO" (FEF grade) manufactured by TOKAI CARBON CO., LTD., iodine adsorption amount 44 g / kg, DBP absorption amount 115 ml / 100 g)

[0086] · Zinc oxide: "Zinc Oxide 2 types" manufactured by Sakai Chemical Industry

[0087] · Stearic acid: "LUNAC S30" manufactured by Kao

[0088] • Processing oil: "SUNTHENE4130" manufactured by Taiyo Oil, Japan

[0089] Amine-based anti-aging agents <1> Seiko Chemical manufactures "OZONONE 6C"

[0090] Amine-based anti-aging agents <2> Seiko Chemical manufactures "NONFLEX RD".

[0091] • Vulcanization accelerator <1> Nocceler CZ, manufactured by Ouchi New Chemical Co., Ltd.

[0092] • Vulcanization accelerator <2> Nocceler TBT, manufactured by Ouchi New Chemical Co., Ltd.

[0093] • Sulfur (vulcanizing agent)

[0094] (Examples 1-5, Comparative Examples 1-5)

[0095] The materials were mixed in the proportions shown in the table and then kneaded using a closed mixer (Banbury type) and rollers to prepare a rubber composition. The properties of the prepared rubber composition were measured and evaluated according to the following methods.

[0096] [hardness]

[0097] Each rubber composition was pressed and vulcanized at 150°C for 20 minutes to produce a rubber sheet with a thickness of 2 mm. JIS 5 dumbbells were punched from these sheets, and the hardness (JIS A) of these dumbbells was determined according to JIS K 6251. In the table, the hardness of Example 1 is set to 100, and the values ​​are shown after exponential conversion.

[0098] [Static stiffness (Ks)]

[0099] Using various rubber compositions, circular plate-shaped fittings (60 mm in diameter and 6 mm in thickness) were pressed onto the upper and lower surfaces of rubber sheets (50 mm in diameter and 25 mm in height) under vulcanization conditions of 170°C for 30 minutes to prepare vulcanized bonded rubber test pieces. Next, the rubber test pieces were compressed 7 mm along the cylindrical axis, and the loads at displacements of 1.5 mm and 3.5 mm were read from the load-displacement curve of the second compression to calculate the static stiffness (Ks (N / mm)). In the table, the static stiffness (Ks) of Example 1 is set to 100, and the values ​​are shown after exponential conversion.

[0100] [Dynamic stiffness (Kd100)]

[0101] The rubber test piece was compressed 2.5 mm along the cylindrical axis. Using this 2.5 mm compression point as the center, a constant displacement of 0.05 mm was applied from below at a frequency of 100 Hz to adjust the compression vibration. The dynamic load was detected using a load sensor at the top, and the dynamic stiffness (Kd100 (N / mm)) was calculated according to JIS K 6394. In the table, the dynamic stiffness (Kd100) of Example 1 is set to 100, and the values ​​are shown after exponential conversion.

[0102] [Dynamic Proportion (Kd100 / Ks)]

[0103] The dynamic ratio is calculated as the ratio of dynamic stiffness (Kd100) to static stiffness (Ks). In the table, the dynamic ratio (Kd100 / Ks) of Example 1 is set to 100, and the values ​​are shown after exponential conversion.

[0104] [Durability]

[0105] Each rubber composition was pressed and vulcanized at 150°C for 30 minutes to produce a rubber sheet with a thickness of 2 mm. Then, a JIS No. 3 dumbbell was punched from this rubber sheet. Using this dumbbell, a tensile fatigue test was performed according to JIS K 6260 to determine the number of durability cycles. In the table, the durability cycles of Example 1 are set to 100, and the values ​​are shown after exponential conversion.

[0106] [Evaluation of Spring Characteristics Relative to Stiffness]

[0107] Plot the data for each embodiment and comparative example with hardness (index) on the horizontal axis and dynamic ratio (index) on the vertical axis. Figure 1 Create a distribution map. For example... Figure 1 As shown, the spring characteristics relative to stiffness generally tend to increase to the right. Using an approximate straight line as a reference, in... Figure 1 In the middle, located on the straight line ( Figure 1 The symbol below the dotted line pointing to the right is “○”, and the symbol above it is “×”.

[0108] [Durability evaluation relative to hardness]

[0109] Plot the data for each embodiment and comparative example with hardness (index) on the horizontal axis and durability cycles (index) on the vertical axis. Figure 2 Create a distribution map. For example... Figure 2 As shown, the durability cycles relative to hardness generally tend to decrease to the right. Using an approximate straight line as a baseline, in... Figure 2 In the middle, located on the straight line ( Figure 2 The symbol above the downward-sloping dotted line in the diagram is “○”, and the symbol below it is “×”.

[0110] [Overall Evaluation]

[0111] Set the case where both the spring characteristics relative to hardness and the durability relative to hardness are "○" to "○", and set the case where either one is "×" to "×".

[0112] [Table 1]

[0113]

[0114] In Comparative Example 1, HAF-grade carbon black (C) was used alone instead of surface-activated carbon black (B) for diene rubber (A). In Comparative Example 1, the spring characteristics were poor relative to the dynamic range of hardness. In Comparative Example 2, FEF-grade carbon black (C) was used instead of surface-activated carbon black (B) for diene rubber (A). That is, FEF-grade carbon black (with low iodine adsorption) and HAF-grade carbon black (C) (with high iodine adsorption) were used. In Comparative Example 2, the durability was poor. In Comparative Example 3, surface-activated carbon black (B) was used alone instead of HAF-grade carbon black (C) for diene rubber (A). In Comparative Example 3, the durability was poor. In Comparative Example 4, both surface-activated carbon black (B) and HAF-grade carbon black (C) were used for diene rubber (A), but the total amount used was excessive. In Comparative Example 4, the spring characteristics were poor relative to the dynamic range of hardness. In addition, the durability was also poor. In Comparative Example 5, compared to diene rubber (A), surface-activated carbon black (B) and HAF-grade carbon black (C) were used, but the amount of surface-activated carbon black (B) used was too small. In Comparative Example 5, the spring characteristics were poor relative to the difference in dynamic ratio of hardness.

[0115] On the other hand, in the embodiments, surface-activated carbon black (B) and HAF-grade carbon black (C) were blended relative to the diene rubber (A), with (B) and (C) in a specific ratio. In the embodiments, the dynamic ratio relative to hardness is good, and the spring characteristics are excellent. In addition, the durability is also excellent.

[0116] As can be seen from the examples and comparative examples above, by blending surface-activated carbon black (B) and HAF-grade carbon black (C) relative to diene rubber (A) in a specific ratio of (B) and (C), it is possible to balance low dynamic range and durability.

[0117] The embodiments and examples of the present invention have been described above, but the present invention is not limited in any way by the above embodiments and examples, and various changes can be made without departing from the spirit of the present invention.

Claims

1. A vibration-damping rubber composition comprising the following components (A) to (C), Relative to 100 parts by weight of (A), the combined quantity of (B) and (C) is 20 parts by weight or more and 70 parts by weight or less. 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. (A) Diene-based rubber (B) Surface-activated carbon black with a hydrogen content (Hc) of over 4500 ppm per gram of carbon black when heated to 1980°C. (C) HAF grade carbon black.

2. The vibration-damping 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, relative to 100 parts by mass of (A).

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

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

5. A vibration damping rubber component comprising a vulcanizate of the vibration damping rubber composition according to any one of claims 1 to 4.

6. The vibration-damping rubber component according to claim 5, used in electric vehicles.

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