High damping rubber composition and viscoelastic damper using same

Abstract

To provide a high attenuation rubber composition capable of more inexpensively producing a viscoelastic body capable of excellently attenuating vibration in a wider range from such a low strain vibration as a wind shake to a high strain vibration by an earthquake, and a viscoelastic damper having a viscoelastic body composed of the high attenuation rubber composition.SOLUTION: A high attenuation rubber composition uses rubber containing SBR with a styrene content of 25 mass%or more and carbon black of 95 to 165 pts.mass per a total amount of the rubber 100 pts.mass, in combination. A viscoelastic damper has a viscoelastic body composed of the high attenuation rubber composition.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a high-damping rubber composition and a viscoelastic damper having a viscoelastic body made of the high-damping rubber composition. [Background technology]

[0002] Viscoelastic bodies are generally formed from a rubber composition that contains crosslinkable rubber and can form a viscoelastic body with high damping performance suitable for various applications through crosslinking, i.e., a high-damping rubber composition (see Patent Document 1, etc.). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-190397 Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 discloses the use of a viscoelastic damper (vibration damper) made of a high-damping rubber composition in which butyl rubber is blended with a styrene-isobutylene block polymer and / or a styrene-isobutylene-styrene block copolymer, and a non-polar alicyclic saturated hydrocarbon resin, in order to improve damping performance not only in the high strain range (strain of about 200%) caused by earthquakes, but also in the low strain range (strain of about 10%) such as that caused by wind sway.

[0005] However, since the high damping rubber composition described in Patent Document 1 contains many special materials as described above, there is a problem in that the compounding cost is high. An object of the present invention is to provide a high-damping rubber composition that can be produced more cost-effectively as a viscoelastic body that can effectively damp vibrations over a wide range, from low-strain vibrations such as those caused by wind to high-strain vibrations caused by earthquakes, and a viscoelastic damper that includes a viscoelastic body made of the high-damping rubber composition. [Means for solving the problem]

[0006] The present invention is a high-damping rubber composition containing a rubber containing styrene-butadiene rubber having a styrene content of 25% by mass or more, and 95 parts by mass or more and 165 parts by mass or less of carbon black per 100 parts by mass of the total amount of the rubber. The present invention also relates to a viscoelastic damper containing a viscoelastic body made of a crosslinked product of the high damping rubber composition of the present invention. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a high-damping rubber composition that can be produced more cost-effectively as a viscoelastic body that can effectively damp vibrations over a wide range, from low-strain vibrations such as those caused by wind to high-strain vibrations caused by earthquakes, and a viscoelastic damper that includes a viscoelastic body made of the high-damping rubber composition. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is an exploded perspective view showing a test specimen as a model of a viscoelastic body made of a high-damping rubber composition according to an example of the present invention and a comparative example, which is prepared in order to evaluate the damping performance of the viscoelastic body. [Figure 2] 1(a) and 1(b) are diagrams for explaining an outline of a testing machine for displacing the test specimen and determining the relationship between the amount of displacement and the load. [Figure 3] 1 is a graph showing an example of a hysteresis loop showing the relationship between the amount of displacement and the load, which is obtained by displacing a test specimen using the above-mentioned testing machine. DETAILED DESCRIPTION OF THE INVENTION

[0009] <High-damping rubber composition> As described above, the high-damping rubber composition of the present invention is characterized by containing rubber containing styrene-butadiene rubber (SBR) having a styrene content of 25% by mass or more, and 95 parts by mass or more and 165 parts by mass or less of carbon black per 100 parts by mass of the total amount of the rubber. According to the high damping rubber composition of the present invention, the interaction between the SBR and the carbon black can cause the viscoelastic body to generate hysteresis loss that contributes to the damping performance of the viscoelastic damper.

[0010] Also, Selecting and using a specific SBR having a styrene content of 25% by mass or more as the SBR, as described above; The proportion of carbon black is to be 95 parts by mass or more per 100 parts by mass of the total amount of rubber containing at least the above-mentioned specific SBR. This enhances the interaction between the SBR and carbon black, resulting in stronger hysteresis loss and improving the damping rate of the viscoelastic body against a wide range of vibrations, from low-strain vibrations such as those caused by wind to high-strain vibrations caused by earthquakes.

[0011] Furthermore, by setting the proportion of carbon black to 165 parts by mass or less per 100 parts by mass of the total amount of the rubber, the rigidity of the viscoelastic body can be prevented from becoming too high, and the damping rate of the viscoelastic body can be further improved against a wide range of vibrations, from low-strain vibrations such as those caused by wind to high-strain vibrations caused by earthquakes. Therefore, according to the high-damping rubber composition of the present invention, it is possible to manufacture a viscoelastic body that can effectively damp vibrations over a wide range, from low-strain vibrations such as those caused by wind to high-strain vibrations caused by earthquakes, at lower cost using only general-purpose materials, without using special materials.

[0012] These facts are also evident from the results of the examples and comparative examples described below. <Rubber> (SBR) As the SBR, a specific SBR having a styrene content of 25% by mass or more is selected from various SBRs synthesized by copolymerizing styrene and 1,3-butadiene using various polymerization methods such as emulsion polymerization and solution polymerization.

[0013] The reason for selecting and using the above specific SBR is that if only general-purpose SBR having a styrene content of less than 25% by mass is used, the damping rate of the viscoelastic body will not be improved over a wide range from low-strain vibration to high-strain vibration, and the effect of effectively damping vibration will not be sufficiently obtained. In contrast, by selecting and using a specific SBR having a styrene content of 25% by mass or more, as described above, the damping rate of the viscoelastic body can be improved over a wide range from low strain vibrations to high strain vibrations, thereby enabling good vibration damping.

[0014] As the specific SBR, various SBRs having a styrene content of 25% by mass or more can be used, up to a high styrene SBR having a styrene content of nearly 90% by mass. However, in consideration of imparting to the viscoelastic body good rubber properties, i.e., flexibility, small compression set, and resistance to settling, it is preferable to use, as the specific SBR, SBR having a styrene content of 28% by mass or more, particularly 30% by mass or more, even within the above range, and it is preferable to use SBR having a styrene content of 50% by mass or less, particularly 40% by mass or less.

[0015] The specific SBR having a styrene content of 25% by mass or more may be an oil-extended type in which the flexibility is adjusted by adding an extender oil, or a non-oil-extended type in which no extender oil is added. Either type of SBR may be used in the present invention. Specific examples of such specific SBR having a styrene content of 25% by mass or more include, but are not limited to, the following various SBRs:

[0016] JSR Corporation's JSR0202 (styrene content: 46.0% by mass, non-oil-extended type) and JSR0122 (styrene content: 37.0% by mass, oil-extended type, amount of oil extension: 25.4 phr). SE6701 (styrene content: 30.0% by mass, oil-extended type, oil extension amount: 15 phr) and SE0372 (styrene content: 33.0% by mass, oil-extended type, oil extension amount: 20 phr) manufactured by Sumitomo Chemical Co., Ltd.

[0017] Nipol (registered trademark) 1739 (styrene content: 40.0% by mass, oil-extended type, oil extension amount: 37.5 phr) and Nipol 9548 (styrene content: 35.0% by mass, oil-extended type, oil extension amount: 37.5 phr), manufactured by Zeon Corporation. One or more of these specific SBRs having a styrene content of 25% by mass or more can be used.

[0018] (other rubber) As the rubber, only a specific SBR having a styrene content of 25% by mass or more may be used, or the specific SBR may be used in combination with other rubbers. Examples of other rubbers include natural rubber, isoprene rubber (IR), butadiene rubber (BR), and also SBR with a styrene content of less than 25% by mass can be used.

[0019] As the natural rubber, for example, one or more of various grades of natural rubber such as SMR (Standard Malaysian Rubber)-CV60 or various deproteinized natural rubbers can be used. As the IR, any one or more of various IRs that have a polyisoprene structure that artificially reproduces the structure of natural rubber, are crosslinkable, and are solid at room temperature before crosslinking can be used.

[0020] As the BR, any of various BRs having a polybutadiene structure in the molecule and having crosslinkability can be used. In particular, high-cis BR having a cis-1,4 bond content of 95% or more is preferred, as it can exhibit good rubber properties over a wide temperature range from high to low. BR is classified into an oil-extended type in which flexibility is adjusted by adding an extender oil, and a non-oil-extended type in which no extender oil is added, and either type of BR may be used in the present invention.

[0021] One or more of these BRs can be used. Furthermore, as described above, various SBRs having a styrene content of less than 25 mass% can be used from among various SBRs synthesized by copolymerizing styrene and 1,3-butadiene by various polymerization methods such as emulsion polymerization and solution polymerization. SBR includes oil-extended types in which the flexibility is adjusted by adding an extender oil, and non-oil-extended types in which no extender oil is added, and either type of SBR may be used in the present invention.

[0022] One or more of these SBRs having a styrene content of less than 25% by mass can be used. However, in consideration of further improving the effects of the present invention by using the rubber in combination with the above-mentioned carbon black, it is preferable to use the above-mentioned specific SBR having a styrene content of 25% by mass or more as the rubber in an amount of 90 parts by mass or more per 100 parts by mass of the total amount of rubber, and it is even more preferable to use only the specific SBR having a styrene content of 25% by mass or more (including the case where two or more types of specific SBR are used in combination) without using the other rubbers described above in combination.

[0023] <Carbon black> As the carbon black, one or more types of carbon black that can function as a filler, such as furnace black, acetylene black, and ketjen black, can be used, which are classified according to the production method, etc. Specific examples of carbon black include, but are not limited to, the following carbon blacks:

[0024] From the SEAT (registered trademark) series manufactured by Tokai Carbon Co., Ltd., SEAT 9H (SAF-HS), SEAT 9 (SAF), SEAT 7HM (N234), SEAT 6 (ISAF), SEAT 600 (ISAF-LS), SEAT 5H (IISAF), SEAT KH (N399), SEAT 3H (HAF-HS), SEAT NH (N351), SEAT 3 (HAF), SEAT N (LI-HAF), SEAT 300 (HAF-LS), SEAT 116HM (MAF-HS), SEAT 116 (MAF), SEAT SO (FEF), SEAT V (GPF), SEAT SVH (SRF-HS), SEAT FY (SRF-HS), SEAT S (SRF), SEAT SP (SRF-LS), SEAT TA (FT class).

[0025] Asahi Carbon Co., Ltd.'s Asahi #95, Asahi #80, Asahi #70, Asahi #70L, Asahi AX-015, Asahi F-200GS, Asahi #65, Asahi #60HN, Asahi #60U, Asahi #55, Asahi #50HG, Asahi #52, Asahi #51, Asahi #50U, Asahi #50, Asahi #35, Asahi #22K, Asahi #15HS, Asahi #15, Asahi #8, and Asahi Thermal. One or more of these carbon blacks can be used.

[0026] <Carbon black ratio> As explained above, the proportion of carbon black is limited to 95 parts by mass or more and 165 parts by mass or less per 100 parts by mass of the total amount of rubber. The reason for this is as explained above. In other words, if the proportion of carbon black is less than this range, the interaction with the specific SBR will not improve the damping rate of the viscoelastic body over a wide range from low strain vibration to high strain vibration, and the effect of effectively damping vibration will not be sufficiently obtained.

[0027] On the other hand, if the proportion of carbon black exceeds the above range, the rigidity of the viscoelastic body becomes too high, which may result in a decrease in the damping rate of the viscoelastic body against a wide range of vibrations, from low-strain vibrations such as those caused by wind to high-strain vibrations caused by earthquakes. In contrast, by setting the proportion of carbon black within the above range, the interaction with the specific SBR improves the damping rate of the viscoelastic body over a wide range from low strain vibrations to high strain vibrations, thereby enabling good vibration damping.

[0028] In order to further improve these effects, even within the above range, the proportion of carbon black is preferably 98 parts by mass or more, particularly 100 parts by mass or more, per 100 parts by mass of the total amount of rubber, and is preferably 163 parts by mass or less, particularly 160 parts by mass or less. Furthermore, when using oil-extended rubber such as SBR, the above ratio is the ratio per 100 parts by mass of the total amount of rubber itself as solid content, excluding the extender oil contained in the oil-extended rubber (the same applies below).

[0029] <Crosslinking component> In order to crosslink the rubber, a crosslinking component is compounded into the high damping rubber composition. As the crosslinking component, a crosslinking agent and a crosslinking accelerator are used in combination. (Crosslinking agent) As the crosslinking agent, a sulfur-based crosslinking agent is particularly preferred.

[0030] Examples of sulfur-based crosslinking agents that can be used include powdered sulfur, oil-treated powdered sulfur, precipitated sulfur, colloidal sulfur, and dispersible sulfur, as well as organic sulfur-containing compounds such as tetramethylthiuram disulfide and N,N-dithiobismorpholine, with sulfur being particularly preferred. The proportion of the crosslinking agent such as sulfur is preferably 0.8 parts by mass or more, particularly 0.9 parts by mass or more, per 100 parts by mass of the total amount of rubber, and is preferably 2.2 parts by mass or less, more preferably 2.1 parts by mass or less, particularly preferably 2 parts by mass or less, and especially preferably 1.9 parts by mass or less.

[0031] When two or more crosslinking agents are used in combination, the total proportion thereof may be within the above range. Furthermore, for example, when oil-treated powdered sulfur, dispersible sulfur, or the like is used as sulfur, the above ratio refers to the ratio of sulfur itself as an active ingredient contained therein. The crosslinking agent functions to crosslink the rubber, thereby suppressing the movement of the rubber and generating a strong hysteresis loss, particularly against low-strain vibrations such as those caused by wind.

[0032] However, if the proportion of the crosslinking agent is less than the above range, such a function cannot be sufficiently obtained, and the damping factor of the viscoelastic body with respect to low-strain vibrations may decrease. On the other hand, if the proportion of the crosslinking agent exceeds the above range, the rigidity of the viscoelastic body may become too high due to crosslinking, and the damping rate of the viscoelastic body may decrease, particularly in response to high-strain shaking caused by earthquakes.

[0033] In contrast, by setting the proportion of the crosslinking agent within the above range, the damping rate of the viscoelastic body can be improved over a wide range from low strain vibrations to high strain vibrations, thereby enabling good vibration damping. (Crosslinking accelerator) Examples of the crosslinking accelerator include sulfenamide accelerators and thiuram accelerators.

[0034] Since the mechanism of crosslinking promotion differs depending on the type of crosslinking accelerator, it is preferable to use two or more types in combination. Among these, examples of sulfenamide accelerators that can be used include one or more of N-cyclohexyl-2-benzothiazolylsulfenamide, N,N-dicyclohexyl-2-benzothiazolylsulfenamide, N-oxydiethylene-2-benzothiazolylsulfenamide, and N-tert-butyl-2-benzothiazolylsulfenamide.

[0035] As the thiuram accelerator, for example, one or more of tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, tetramethylthiuram monosulfide, tetrakis(2-ethylhexyl)thiuram disulfide, dipentamethylenethiuram tetrasulfide, etc. can be used. The proportion of the crosslinking accelerator is preferably at least 0.5 parts by mass, and at most 2.2 parts by mass, particularly preferably at most 2 parts by mass, per 100 parts by mass of the total amount of rubber.

[0036] When two or more crosslinking agents are used in combination, the total proportion thereof may be within the above range. The crosslinking accelerator acts to suppress the movement of the rubber by crosslinking the rubber with the crosslinking agent, thereby assisting in the function of generating strong hysteresis loss, particularly in response to low-strain vibrations such as those caused by wind. However, if the proportion of the crosslinking accelerator is less than the above range, this function cannot be sufficiently obtained, and the damping factor of the viscoelastic body with respect to low strain vibrations may decrease.

[0037] On the other hand, if the proportion of the crosslinking accelerator exceeds the above range, the rigidity of the viscoelastic body may become too high due to crosslinking, and the damping rate of the viscoelastic body may decrease, particularly in response to high-strain shaking caused by earthquakes. In contrast, by setting the proportion of the crosslinking accelerator within the above range, the damping rate of the viscoelastic body can be improved over a wide range from low strain vibrations to high strain vibrations, thereby enabling good vibration damping.

[0038] <Other ingredients> In addition to the above components, the high damping rubber composition of the present invention may further contain process oil, a tackifier, a softener, an antioxidant, a crosslinking aid, etc. in appropriate proportions. (process oil) As the process oil, various process oils that can function as a plasticizer, processing aid, etc. for the high damping rubber composition can be used.

[0039] Such process oils include, for example, at least one oil selected from the group consisting of paraffinic oils, naphthenic oils, and aromatic oils. The proportion of oil containing at least process oil is preferably 35 parts by mass or less per 100 parts by mass of carbon black. Furthermore, in consideration of improving the processability of the high-damping rubber composition, it is particularly preferable that the proportion of oil is 30 parts by mass or less per 100 parts by mass of carbon black.

[0040] If the oil ratio exceeds this range, the mixture that forms the base of the high-damping rubber composition may become too soft and difficult to knead, making it difficult to prepare the high-damping rubber composition. In addition, the prepared high-damping rubber composition may be too soft, and when an attempt is made to pull it out of the kneader after kneading, it may stretch significantly, which may result in it taking a long time to remove the entire amount from the kneader or making it difficult to mold into the shape of a viscoelastic body.

[0041] In other words, the processability of the high-damping rubber composition may be reduced. In contrast, by setting the oil ratio within the above range, a high-damping rubber composition can be prepared while maintaining an easy-to-knead state, and a viscoelastic body can be produced while preventing the prepared high-damping rubber composition from becoming too soft. That is, the processability of the high-damping rubber composition can be improved.

[0042] When non-oil extended rubber is used as the rubber, the amount of process oil may be adjusted to fall within the above range. Furthermore, as described above, when oil-extended rubber is used as the rubber, the proportion of process oil may be adjusted so that the total amount of oil, including the amount of extended oil contained in the oil-extended rubber, falls within the above range.

[0043] (tackifier) Examples of tackifiers include terpene resins, rosin resins, and petroleum resins. Among these, terpene resins include, for example, α-pinene resin, β-pinene resin, terpene phenol resin, aromatic modified terpene resin, hydrogenated products of these resins, and modified products of these resins with the addition of maleic anhydride.

[0044] One or more of these terpene resins can be used. As the rosin-based resin, various derivatives that contain rosin as a constituent component, such as esters of rosin and polyhydric alcohols and rosin-modified maleic acid resins, and that function as tackifiers and have the effect of improving the damping performance of viscoelastic materials, can be used. Examples of rosin-based resins include rosins such as gum rosin, wood rosin, and tall rosin, as well as hydrogenated rosins, disproportionated rosins, maleic acid-modified rosins, fumaric acid-modified rosins, (meth)acrylic acid-modified rosins, esterified rosins condensed with alcohols, and phenol-modified rosins, which are made from such rosins.

[0045] Specific examples of the rosin-based resin include, but are not limited to, the following various rosin-based resins. Among the Pine Crystal (registered trademark) series manufactured by Arakawa Chemical Industries, Ltd., KR-85 (softening point: 80 to 87°C), KR-612 (softening point: 80 to 90°C), KR-614 (softening point: 84 to 94°C), KE-100 (softening point: 95 to 105°C), KE-311 (softening point: 90 to 100°C), KE-359 (softening point: 94 to 104°C), and KE-604 (softening point: 124 to 134°C).

[0046] From the Harie Star series manufactured by Harima Chemical Co., Ltd.: MSR-4 (softening point: 127°C), DS-130 (softening point: 135°C), AD-130 (softening point: 135°C), DS-816 (softening point: 148°C), DS-822 (softening point: 172°C). Harima Chemical Co., Ltd.'s Harimac series includes 145P (softening point: 138°C), 135GN (softening point: 139°C), and AS-5 (softening point: 165°C).

[0047] One or more of these rosin-based resins can be used. Further examples of petroleum-based resins include dicyclopentadiene-based resins, C5-based petroleum resins, C9-based petroleum resins, C5C9-based petroleum resins, hydrogenated products of these resins, and modified products of these resins with the addition of cyclic polybasic acid anhydrides. Among these, dicyclopentadiene resins and / or C9 petroleum resins are preferred.

[0048] The dicyclopentadiene resin is not limited to this, but examples thereof include Marucaretz (registered trademark) M890A (softening point: 105° C.) manufactured by Maruzen Petrochemical Co., Ltd. Specific examples of C9 petroleum resins include, but are not limited to, Petcol (registered trademark) LX (weight average molecular weight 1400, softening point 98° C.) manufactured by Tosoh Corporation.

[0049] One or more of these petroleum-based resins can be used. The proportion of the tackifier is preferably 80 parts by mass or less, particularly preferably 70 parts by mass or less, per 100 parts by mass of carbon black. Furthermore, in consideration of improving the processability of the high-damping rubber composition, it is particularly preferable that the proportion of the tackifier be 60 parts by mass or less per 100 parts by mass of carbon black.

[0050] If the proportion of the tackifier exceeds this range, the processability of the high damping rubber composition may decrease. That is, the mixture that is the base of the high-damping rubber composition may have too high viscosity or stickiness, making it difficult to knead, and making it difficult to prepare the high-damping rubber composition. In addition, the prepared high-damping rubber composition may be so sticky that it takes a long time to remove the entire amount from the kneader after kneading, or it may not be easy to mold it into the shape of a viscoelastic body.

[0051] In contrast, by setting the proportion of tackifier within the above range, a high-damping rubber composition can be prepared while maintaining an easy-to-knead state, and a viscoelastic body can be produced while preventing the prepared high-damping rubber composition from becoming too tacky. In other words, the processability of the high-damping rubber composition can be improved. When two or more tackifiers are used in combination, the total proportion thereof may be within the above range.

[0052] (softener) The softener is a component for further improving the processability of the high damping rubber composition, and examples of the softener include coal-based resins. Examples of coal-based resins include coumarone resins, coumarone-indene resins, hydrogenated versions of these resins, and modified versions of these resins with the addition of cyclic polybasic acid anhydrides.

[0053] Among these, coumarone-indene resin is preferred. The coumarone-indene resin is mainly composed of a polymer of coumarone and indene, has a relatively low molecular weight of about 1000 or less, and various coumarone-indene resins that can function as softeners can be used. Examples of the coumarone-indene resin include, but are not limited to, Nitto Chemical Co., Ltd.'s Knit Resin (registered trademark) Coumarone G-90 (average molecular weight: 770, softening point: 90°C, acid value: 1.0 KOHmg / g or less, hydroxyl value: 25 KOHmg / g, bromine value: 9 g / 100 g) and G-100N (average molecular weight: 730, softening point: 100°C, acid value: 1.0 KOHmg / g or less, hydroxyl value: 25 KOHmg / g, bromine value: 9 g / 100 g). One or more of the following can be used: V-120 [average molecular weight: 960, softening point: 120°C, acid value: 1.0 KOHmg / g or less, hydroxyl value: 30 KOHmg / g, bromine value: 6 g / 100 g], V-120 [average molecular weight: 960, softening point: 120°C, acid value: 1.0 KOHmg / g or less, hydroxyl value: 30 KOHmg / g, bromine value: 7 g / 100 g], V-120S [average molecular weight: 950, softening point: 120°C, acid value: 1.0 KOHmg / g or less, hydroxyl value: 30 KOHmg / g, bromine value: 7 g / 100 g].

[0054] The proportion of the coumarone-indene resin is preferably 3 parts by mass or more and 20 parts by mass or less per 100 parts by mass of the total amount of rubber. (anti-aging agent) As the anti-aging agent, for example, one or more of various anti-aging agents such as benzimidazole-based, quinone-based, polyphenol-based, and amine-based anti-aging agents can be used, and it is particularly preferable to use a benzimidazole-based anti-aging agent in combination with a quinone-based anti-aging agent.

[0055] Among these, the benzimidazole-based antioxidants include, for example, 2-mercaptobenzimidazole. The proportion of the benzimidazole antioxidant is preferably 0.5 parts by mass or more and 5 parts by mass or less per 100 parts by mass of the total amount of rubber. As a specific example of a quinone-based anti-aging agent, Antigen FR (aromatic ketone-amine condensate) manufactured by Maruishi Chemicals Co., Ltd. can be used.

[0056] The proportion of the quinone antioxidant is preferably 0.5 parts by mass or more and 5 parts by mass or less per 100 parts by mass of the total amount of rubber. (Crosslinking aid) As the crosslinking aid, for example, one or more of metal compounds such as zinc oxide; fatty acids such as stearic acid, oleic acid, cottonseed fatty acid, and other conventionally known crosslinking aids can be used, and it is particularly preferable to use zinc oxide and stearic acid in combination.

[0057] Of these, the proportion of zinc oxide is preferably 1 part by mass or more and 5 parts by mass or less per 100 parts by mass of the total rubber, and the proportion of stearic acid is preferably 1 part by mass or more and 3 parts by mass or less per 100 parts by mass of the total rubber. <High Damping Rubber Composition> The high-damping rubber composition of the present invention containing the above-mentioned components can be used to form, for example, a viscoelastic body that constitutes a viscoelastic bearing for seismic isolation that is incorporated into the foundation of a building or other structure, or a viscoelastic damper for vibration control that is incorporated into the structure of a building.

[0058] Furthermore, the high damping rubber composition of the present invention can also be used to form various viscoelastic bodies used, for example, as vibration-damping members for cables of suspension bridges, cable-stayed bridges, etc.; vibration-proof members for industrial machinery, aircraft, automobiles, railway vehicles, etc.; vibration-proof members for computers and their peripheral devices, household electrical appliances, etc. Moreover, according to the present invention, by adjusting the types, combinations, and proportions of various components, such as rubber containing a specific SBR with a styrene content of 25% by mass or more, carbon black, crosslinking components, and other components, it is possible to provide each viscoelastic body with excellent damping performance suitable for each application.

[0059] Viscoelastic damper In particular, when the high-damping rubber composition of the present invention is used as a forming material to form a viscoelastic body for a vibration damper for buildings as a viscoelastic damper to be incorporated into high-rise buildings, etc., a wide range of vibrations can be effectively suppressed, from low-strain vibrations such as those caused by wind to high-strain vibrations caused by earthquakes. [Example]

[0060] The present invention will be further explained below based on examples and comparative examples, but the configuration of the present invention is not necessarily limited to these examples. Example 1 115 parts by mass (100 parts by mass of SBR as solid content) [SE6701 manufactured by Sumitomo Chemical Co., Ltd., styrene content: 30.0% by mass, oil-extended type, oil extension amount: 15 phr] and 140 parts by mass of carbon black [SEAST 3 (HAF) manufactured by Tokai Carbon Co., Ltd.] were blended with the components shown in Table 1 below and kneaded using an internal kneader.

[0061] [Table 1]

[0062] The components in the table are as follows: The parts by mass in the table are 140 parts by mass of oil-extended SBR, that is, parts by mass per 100 parts by mass of SBR as solid content. Process oil: naphthenic, A / O mix manufactured by Sankyo Yuka Kogyo Co., Ltd. Dicyclopentadiene resin: tackifier, Maruzen Petrochemical Co., Ltd.'s MARKAREZ M890A C9 petroleum resin: tackifier, Petcol LX manufactured by Tosoh Corporation Benzimidazole antioxidant: 2-mercaptobenzimidazole, Nocrac (registered trademark) MB manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Quinone-based anti-aging agent: Antigen FR manufactured by Maruishi Chemicals Co., Ltd. Coumarone-indene resin: softening point 90℃, knit resin Coumarone G-90 manufactured by Nippon Paint Chemical Co., Ltd. Zinc oxide type 2: manufactured by Mitsui Mining & Smelting Co., Ltd. Stearic acid: "Tsubaki" manufactured by NOF Corporation Next, the crosslinking components shown in Table 2 below were added and further kneaded to prepare high damping rubber compositions.

[0063] [Table 2]

[0064] The components in the table are as follows: The parts by mass in the table are 140 parts by mass of oil-extended SBR, that is, parts by mass per 100 parts by mass of SBR as solid content. 5% oil-treated powdered sulfur: vulcanizing agent, manufactured by Tsurumi Chemical Industry Co., Ltd., the amount of sulfur itself is 1.425 parts by mass Sulfenamide accelerator: N-cyclohexyl-2-benzothiazolyl sulfenamide, ACCEL® CZ manufactured by Kawaguchi Chemical Industry Co., Ltd. Thiuram accelerator: Tetraethylthiuram disulfide, ACCEL TET manufactured by Kawaguchi Chemical Industry Co., Ltd. The proportion of carbon black per 100 parts by mass of SBR as solid content was 140 parts by mass, the proportion of sulfur itself as a crosslinking agent was 1.425 parts by mass, and the total proportion of the two crosslinking accelerators was 1.0 part by mass.

[0065] The proportion of oil including extender oil per 100 parts by mass of carbon black was 28.6 parts by mass, and the total proportion of the two types of tackifiers was 57.1 parts by mass. Example 2 A high-damping rubber composition was prepared in the same manner as in Example 1, except that 125.4 parts by mass (100 parts by mass of SBR as solid content) of oil-extended SBR with a styrene content of 37.0% by mass [JSR0122 manufactured by JSR Corporation, styrene content: 37.0% by mass, oil-extended type, amount of oil extension: 25.4 phr] was used as the SBR, and the amount of process oil was 15.0 parts by mass.

[0066] The proportion of carbon black per 100 parts by mass of SBR as solid content was 140 parts by mass, the proportion of sulfur itself as a crosslinking agent was 1.425 parts by mass, and the total proportion of the two crosslinking accelerators was 1.0 part by mass. The proportion of oil including extender oil per 100 parts by mass of carbon black was 28.9 parts by mass, and the total proportion of the two types of tackifiers was 57.1 parts by mass.

[0067] Example 3 A high-damping rubber composition was prepared in the same manner as in Example 1, except that 137.5 parts by mass (100 parts by mass of SBR as solids) of oil-extended SBR with a styrene content of 40.0% (Nipol 1739 manufactured by Nippon Zeon Co., Ltd. [styrene content: 40.0% by mass, oil-extended type, amount of oil extension: 37.5 phr] was used as the SBR, and the amount of process oil was 3.0 parts by mass.

[0068] The proportion of carbon black per 100 parts by mass of SBR as solid content was 140 parts by mass, the proportion of sulfur itself as a crosslinking agent was 1.425 parts by mass, and the total proportion of the two crosslinking accelerators was 1.0 part by mass. The proportion of oil including extender oil per 100 parts by mass of carbon black was 28.9 parts by mass, and the total proportion of the two types of tackifiers was 57.1 parts by mass.

[0069] Example 4 A high-damping rubber composition was prepared in the same manner as in Example 1, except that the amount of carbon black was 100 parts by mass and the amount of process oil was 14.0 parts by mass per 115 parts by mass of oil-extended SBR. The proportion of carbon black per 100 parts by mass of SBR as solid content was 100 parts by mass, the proportion of sulfur itself as a crosslinking agent was 1.425 parts by mass, and the total proportion of the two crosslinking accelerators was 1.0 part by mass.

[0070] The proportion of oil including extender oil per 100 parts by mass of carbon black was 29.0 parts by mass, and the total proportion of the two types of tackifiers was 80.0 parts by mass. Example 5 A high-damping rubber composition was prepared in the same manner as in Example 1, except that the amount of carbon black was 160 parts by mass and the amount of process oil was 30.0 parts by mass per 115 parts by mass of oil-extended SBR.

[0071] The proportion of carbon black per 100 parts by mass of SBR as solid content was 160 parts by mass, the proportion of sulfur itself as a crosslinking agent was 1.425 parts by mass, and the total proportion of the two crosslinking accelerators was 1.0 part by mass. The proportion of oil including extender oil per 100 parts by mass of carbon black was 28.1 parts by mass, and the total proportion of the two types of tackifiers was 50.0 parts by mass.

[0072] Example 6 A high-damping rubber composition was prepared in the same manner as in Example 1, except that the amount of process oil was 30.0 parts by mass per 115 parts by mass of oil-extended SBR. The proportion of carbon black per 100 parts by mass of SBR as solid content was 140 parts by mass, the proportion of sulfur itself as a crosslinking agent was 1.425 parts by mass, and the total proportion of the two crosslinking accelerators was 1.0 part by mass.

[0073] The proportion of oil including extender oil per 100 parts by mass of carbon black was 32.1 parts by mass, and the total proportion of the two types of tackifiers was 57.1 parts by mass. Example 7 A high-damping rubber composition was prepared in the same manner as in Example 1, except that the amount of process oil was 15.0 parts by mass and the amount of dicyclopentadiene resin among the tackifiers was 50.0 parts by mass per 115 parts by mass of oil-extended SBR.

[0074] The proportion of carbon black per 100 parts by mass of SBR as solid content was 140 parts by mass, the proportion of sulfur itself as a crosslinking agent was 1.425 parts by mass, and the total proportion of the two crosslinking accelerators was 1.0 part by mass. The proportion of oil including extender oil per 100 parts by mass of carbon black was 21.4 parts by mass, and the total proportion of the two types of tackifiers was 64.3 parts by mass.

[0075] Example 8 A high-damping rubber composition was prepared in the same manner as in Example 1, except that the amount of process oil was 30.0 parts by mass and the amount of dicyclopentadiene resin among the tackifiers was 50.0 parts by mass per 115 parts by mass of oil-extended SBR. The proportion of carbon black per 100 parts by mass of SBR as solid content was 140 parts by mass, the proportion of sulfur itself as a crosslinking agent was 1.425 parts by mass, and the total proportion of the two crosslinking accelerators was 1.0 part by mass.

[0076] The proportion of oil including extender oil per 100 parts by mass of carbon black was 32.1 parts by mass, and the total proportion of the two types of tackifiers was 64.3 parts by mass. Example 9 A high-damping rubber composition was prepared in the same manner as in Example 1, except that the amount of 5% oil-treated powdered sulfur was 1.0 part by mass (the amount of sulfur itself was 0.95 part by mass) per 115 parts by mass of oil-extended SBR.

[0077] The proportion of carbon black per 100 parts by mass of SBR as solid content was 140 parts by mass, the proportion of sulfur itself as a crosslinking agent was 0.95 parts by mass, and the total proportion of the two crosslinking accelerators was 1.0 part by mass. The proportion of oil including extender oil per 100 parts by mass of carbon black was 28.6 parts by mass, and the total proportion of the two types of tackifiers was 57.1 parts by mass.

[0078] Example 10 A high-damping rubber composition was prepared in the same manner as in Example 1, except that the amount of 5% oil-treated powdered sulfur was 2.0 parts by mass (the amount of sulfur itself was 1.90 parts by mass) per 115 parts by mass of oil-extended SBR. The proportion of carbon black per 100 parts by mass of SBR as solid content was 140 parts by mass, the proportion of sulfur itself as a crosslinking agent was 1.90 parts by mass, and the total proportion of the two crosslinking accelerators was 1.0 part by mass.

[0079] The proportion of oil including extender oil per 100 parts by mass of carbon black was 28.6 parts by mass, and the total proportion of the two types of tackifiers was 57.1 parts by mass. Example 11 A high-damping rubber composition was prepared in the same manner as in Example 1, except that no thiuram-based crosslinking accelerator was added.

[0080] The proportion of carbon black per 100 parts by mass of SBR as a solid content was 140 parts by mass, the proportion of sulfur itself as a crosslinking agent was 1.425 parts by mass, and the proportion of the crosslinking accelerator was 0.5 parts by mass. The proportion of oil including extender oil per 100 parts by mass of carbon black was 28.6 parts by mass, and the total proportion of the two types of tackifiers was 57.1 parts by mass.

[0081] Comparative Example 1 A high-damping rubber composition was prepared in the same manner as in Example 1, except that 100 parts by mass of non-oil-extended SBR having a styrene content of 23.5% by mass (JSR1502 manufactured by JSR Corporation, styrene content: 23.5% by mass, non-oil-extended) was used as the SBR, the amount of carbon black was 160 parts by mass, and the amount of process oil was 30.0 parts by mass.

[0082] The proportion of carbon black per 100 parts by mass of SBR as solid content was 160 parts by mass, the proportion of sulfur itself as a crosslinking agent was 1.425 parts by mass, and the total proportion of the two crosslinking accelerators was 1.0 part by mass. The proportion of process oil per 100 parts by mass of carbon black was 18.8 parts by mass, and the total proportion of the two types of tackifiers was 50.0 parts by mass.

[0083] Comparative Example 2 A high-damping rubber composition was prepared in the same manner as in Example 1, except that the amount of carbon black was 90 parts by mass and the amount of process oil was 10.0 parts by mass per 115 parts by mass of oil-extended SBR. The proportion of carbon black per 100 parts by mass of SBR as solid content was 90 parts by mass, the proportion of sulfur itself as a crosslinking agent was 1.425 parts by mass, and the total proportion of the two crosslinking accelerators was 1.0 part by mass.

[0084] The proportion of oil including extender oil per 100 parts by mass of carbon black was 27.8 parts by mass, and the total proportion of the two types of tackifiers was 88.9 parts by mass. Comparative Example 3 A high-damping rubber composition was prepared in the same manner as in Example 1, except that the amount of carbon black was 170 parts by mass per 115 parts by mass of oil-extended SBR.

[0085] The proportion of carbon black per 100 parts by mass of SBR as solid content was 170 parts by mass, the proportion of sulfur itself as a crosslinking agent was 1.425 parts by mass, and the total proportion of the two crosslinking accelerators was 1.0 part by mass. The proportion of oil including extender oil per 100 parts by mass of carbon black was 23.5 parts by mass, and the total proportion of the two types of tackifiers was 47.1 parts by mass.

[0086] <Damping performance test> (Preparation of test specimen) The high-damping rubber compositions produced in the examples and comparative examples were extruded into sheets and then punched out to form flat plates 1 (8 mm thick x 40 mm long x 40 mm wide) with a rectangular planar shape as shown in Figure 1.

[0087] Next, rectangular flat steel plates 2 measuring 6 mm thick x 44 mm long x 44 mm wide were placed on both the front and back sides of the formed flat plate 1 via a vulcanizing adhesive to form a laminate. The laminate was then heated to 170°C while being pressed in the lamination direction to crosslink the high-damping rubber composition forming the plate 1, and the plate 1 was vulcanized and bonded to two steel plates 2 to produce a test specimen 3 for evaluating damping performance as a model of a viscoelastic body.

[0088] (Displacement test) Two of the above test specimens 3 were prepared as shown in Figure 2(a), and each of the two test specimens 3 was fixed to one central fixing jig 4 via one of the steel plates 2, and one left and one right fixing jig 5 were fixed to each of the other steel plates 2 of both test specimens 3. Next, the central fixing jig 4 was fixed to an upper fixing arm 6 of a testing machine (not shown) via a joint 7, and the two left and right fixing jigs 5 were fixed to a lower movable platen 8 of the testing machine via a joint 9.

[0089] Both test specimens 3 were fixed as described above in a state in which two parallel sides of the flat plate 1 were aligned parallel to the displacement direction described below. Next, the following operations (I) and (II) were considered as one cycle, and the plate 1 was repeatedly subjected to strain deformation, i.e., vibration, and a hysteresis loop H (see Figure 3) showing the relationship between the displacement (mm) in the direction perpendicular to the thickness of the plate 1 and the load (N) was obtained.

[0090] (I): The movable platen 8 is displaced so as to be pushed upward toward the fixed arm 6 as shown by the white arrow in Figure 2(a), causing the flat plate 1 to be distorted and deformed in the direction perpendicular to the thickness direction as shown in Figure 2(b). (II): From the above state, the movable platen 8 is displaced so as to be pulled down in the direction opposite to the direction of the fixed arm 6, as shown by the white arrow in Figure 2(b), to return to the state shown in Figure 2(a).

[0091] The measurement was carried out in an environment at a temperature of 23°C, by carrying out three cycles of the above operations (I) and (II), and the value at the third cycle was determined. The maximum displacement amount in each cycle was set so that the amount of deviation of the two steel plates 2 sandwiching the flat plate 1 in the thickness direction and perpendicular direction of the flat plate 1 was the following value relative to the thickness of the flat plate 1. 2% low-distortion vibrations, such as wind sway 100% reproduction of high strain shaking caused by earthquakes From the hysteresis loop H in Figure 3 obtained by measurement, equation (i):

[0092]

number

[0093] The equivalent shear modulus Geq (N / mm 2 ) was sought. In the formula, Keq (N / mm) is the slope of the straight line L1 shown by the thick solid line in Figure 3, which connects the maximum displacement point and the minimum displacement point of the hysteresis loop H, T (mm) is the thickness of the flat plate 1, and A (mm 2 ) is the cross-sectional area of ​​plate 1. Furthermore, from the hysteresis loop H in FIG. 3, formula (ii):

[0094]

number

[0095] The equivalent damping constant Heq was calculated by ΔW in the formula is the amount of absorbed energy represented by the total surface area of ​​the hysteresis loop H, which is shown by the hatched area in FIG. W is the elastic strain energy, which is expressed as the surface area of ​​the triangle surrounded by the line L1, the horizontal axis of the graph, and the perpendicular line L2 drawn from the intersection of the line L1 and the hysteresis loop H to the horizontal axis, as shown by the hatched line in the figure.

[0096] <evaluation> In a test with a maximum displacement of 2%, which reproduced low-strain vibrations such as those caused by wind, the equivalent shear modulus Geq was 10 N / mm 2 Pass the following (○), 10N / mm 2 The equivalent damping constant Heq was evaluated as pass (◯) if it was 0.25 or more, and as fail (×) if it was less than 0.25.

[0097] In addition, in a test with a maximum displacement of 100%, which reproduced the high strain shaking caused by an earthquake, the equivalent shear modulus Geq was 1.0 N / mm 2 Pass the following (○): 1.0N / mm 2 The equivalent damping constant Heq was evaluated as pass (◯) if it was 0.25 or more, and as fail (×) if it was less than 0.25. The results are shown in Tables 3 to 5.

[0098] In each table, "relative to CB100" in the oil and tackifier columns indicates the parts by mass of both components per 100 parts by mass of carbon black. In addition, "extender oil" in the oil column indicates the parts by mass of extender oil in SBR. In the tackifier column, "M890" indicates Marukaretz M890A, and "LX" indicates Petcol LX.

[0099] The parts by mass of sulfur indicate the parts by mass of sulfur itself as an active ingredient contained in the oil-treated powdered sulfur.

[0100] [Table 3]

[0101] [Table 4]

[0102] [Table 5]

[0103] The results of Examples 1, 4, and 5 and Comparative Examples 1 to 3 in Tables 3 to 5 show that by combining rubber containing SBR with a styrene content of 25% by mass or more with 95 to 165 parts by mass of carbon black per 100 parts by mass of the total rubber, it is possible to produce a viscoelastic body that can effectively damp vibrations over a wide range, from low-strain vibrations to high-strain vibrations, at a lower cost. Furthermore, the results of Examples 1 to 3 show that various SBRs having a styrene content of 25% by mass or more can be used.

[0104] From the results of Examples 1, 9 to 11, it was found that the proportion of the cross-linking agent is preferably 0.8 to 2.2 parts by mass per 100 parts by mass of the total amount of rubber, and the proportion of the cross-linking accelerator is preferably 0.5 to 2.2 parts by mass per 100 parts by mass of the total amount of rubber. Furthermore, Examples 1 to 5 and Examples 9 to 11 were easier to knead and mold than Examples 6 to 8, and had better processability. From the viewpoint of processability, it was found that the ratio of oil per 100 parts by mass of carbon black is preferably 30 parts by mass or less, and the ratio of tackifier is preferably 60 parts by mass or less. [Explanation of symbols]

[0105] 1 flat plate 2 steel plate 3 Test specimen 4 Central Fixture 5 Left and right fixing jig 6 Fixed Arm 7 Joint 8 Movable plate 9 Joint H Hysteresis Loop L1 straight line L2 perpendicular W elastic strain energy ΔW Amount of absorbed energy

Claims

1. A high damping rubber composition comprising a rubber containing a styrene-butadiene rubber having a styrene content of 25 mass% or more, and 95 mass parts or more and 165 mass parts or less of carbon black per 100 mass parts of the total amount of the rubber.

2. The high damping rubber composition according to claim 1, further comprising a crosslinking agent as a crosslinking component for crosslinking the rubber, the proportion of the crosslinking agent being 0.8 parts by mass or more and 2.2 parts by mass or less per 100 parts by mass of the total amount of the rubber.

3. 3. The high damping rubber composition according to claim 2, further comprising a crosslinking accelerator as the crosslinking component, the proportion of the crosslinking accelerator being 0.5 parts by mass or more and 2.2 parts by mass or less per 100 parts by mass of the total amount of the rubber.

4. A viscoelastic damper comprising a viscoelastic body made of a cross-linked product of a high damping rubber composition described in any one of claims 1 to 3.

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