Rubber composition for seismic isolation rubber laminate, and seismic isolation rubber laminate

Abstract

Provided are: a rubber composition for a seismic isolation rubber laminate, the composition having an excellent effect in suppressing hardening phenomenon; and a seismic isolation rubber laminate.　This rubber composition for a seismic isolation rubber laminate is to be used in a rubber layer of a seismic isolation rubber laminate, and contains the following (A)-(C) components. The contained amount of (B) the component with respect to 100 parts by mass of (A) the component is 10-30 parts by mass.　(A) An isoprene rubber and / or a butadiene rubber. (B) A plasticizing agent having a molecular weight of 300-900. (C) A carbon black that exhibits an DBP oil absorption amount of 100 ml / 100 g or more, an iodine adsorption amount of 150 mg / g or more, and a nitrogen adsorption specific surface area of 140 m2 / g or more.

Description

Rubber composition for seismic isolation rubber laminate and seismic isolation rubber laminate

[0001] The present invention relates to a rubber composition for a seismic isolation rubber laminate and a seismic isolation rubber laminate. Specifically, it relates to a seismic isolation rubber laminate for supporting structures for civil engineering and construction, and a rubber composition for a seismic isolation rubber laminate used for the rubber layer of the seismic isolation rubber laminate.

[0002] Conventionally, seismic isolation rubber laminates (rubber bearings) have been used for supporting structures in fields such as civil engineering and construction. The seismic isolation rubber laminate is, for example, sometimes arranged to be interposed between the superstructure and the substructure of a structure such as a building.

[0003] The seismic isolation rubber laminate usually has a laminate structure in which a rigid plate such as a metal plate and a rubber layer are alternately laminated. Specifically, for example, as shown in FIG. 1, in the seismic isolation rubber laminate 10, a plurality of metal plates 14 as rigid plates are embedded in the rubber block 12 at a predetermined interval, so that such a metal plate 14 and the rubber layer 16 which is the rubber block 12 portion located between these metal plates 14, 14 are alternately and integrally laminated. Further, on the upper and lower portions of the rubber block 12, metal upper mounting plates 18 and lower mounting plates 20 are fixed, respectively. When these seismic isolation rubber laminates are installed in the foundation part of a building, the shaking of an earthquake is not directly transmitted to the building, the shaking of the upper floors is also alleviated, the period of the shaking becomes longer, and a desired seismic isolation effect is achieved.

[0004] Japanese Patent No. 4120602

[0005] By the way, the seismic isolation rubber laminate is usually used under the condition that the shear strain γ of the rubber is generally in the linear range. However, when an unexpected earthquake or the like occurs, if the above shear strain γ exceeds a predetermined range, a hardening phenomenon (a phenomenon in which the rigidity value of the shear deformation rapidly increases) occurs in the rubber layer, and there is a risk that the superstructure may be damaged or the laminated rubber may break. In the conventional seismic isolation rubber laminate, the effect of suppressing the above hardening phenomenon was insufficient.

[0006] The present invention has been made in view of the above circumstances, and provides a rubber composition for seismic isolation rubber laminates and a seismic isolation rubber laminate that can effectively suppress the hardening phenomenon that occurs during high displacement.

[0007] The inventors of the present invention conducted extensive research to solve the above problems. In the course of this research, they discovered that hardening can be effectively suppressed by a rubber composition in which a specific rubber component, a specific plasticizer, and a specific carbon black are combined, and the content of the plasticizer is within a specific range, thus arriving at the present invention.

[0008] In other words, the gist of the present invention is as follows: [1] A rubber composition for seismic isolation rubber laminates used in the rubber layer of a seismic isolation rubber laminate, comprising the following components (A) to (C), wherein the content of component (B) is 10 to 30 parts by mass per 100 parts by mass of component (A). (A) At least one of isoprene rubber and butadiene rubber (B) A plasticizer with a molecular weight of 300 to 900 (C) A DBP oil absorption amount of 100 ml / 100 g or more, an iodine adsorption amount of 150 mg / g or more, and a nitrogen adsorption specific surface area of ​​140 m 2 [2] A rubber composition for seismic isolation rubber laminates according to [1], wherein the above component (B) is an adipic acid ester plasticizer having a molecular weight of 300 to 900. [3] A rubber composition for seismic isolation rubber laminates according to [1] or [2], wherein the content of the above component (C) is 30 to 150 parts by mass per 100 parts by mass of the above component (A). [4] A rubber composition for seismic isolation rubber laminates according to any one of [1] to [3], wherein the above component (A) is isoprene rubber, and the content of the above isoprene rubber is 70% by mass or more of the total amount of rubber components contained in the above rubber composition for seismic isolation rubber laminates. [5] A seismic isolation rubber laminate having a rubber layer made of the rubber composition for seismic isolation rubber laminates according to any one of [1] to [4] and a layer made of a metal plate.

[0009] According to the present invention, a rubber composition for seismic isolation rubber laminates and a seismic isolation rubber laminate with excellent hardening suppression effect can be provided.

[0010] This is an explanatory diagram showing a typical example of a seismic isolation rubber laminate. This is a schematic diagram of the apparatus used to perform the evaluation method described in the example. This is a diagram showing the load-strain loop curve in the evaluation method described in the example.

[0011] Next, embodiments of the present invention will be described in detail. However, the present invention is not limited to these embodiments.

[0012] In this specification, "X or / and Y (where X and Y are any configuration)" means at least one of X and Y, and can mean X only, Y only, or X and Y. Furthermore, in the numerical ranges described in steps in this specification, the upper or lower limit of one step in the numerical range can be arbitrarily combined with the upper or lower limit of another step in the numerical range. In addition, in the numerical ranges described in this specification, the upper or lower limit of that numerical range can be replaced with the values ​​shown in the examples.

[0013] A rubber composition for seismic isolation rubber laminates according to one embodiment of the present invention (hereinafter sometimes referred to as "this rubber composition") contains the following components (A) to (C), and is characterized in that the content of component (B) is 10 to 30 parts by mass per 100 parts by mass of component (A). (A) At least one of isoprene rubber and butadiene rubber (B) Plasticizer with a molecular weight of 300 to 900 (C) DBP oil absorption amount of 100 ml / 100 g or more, iodine adsorption amount of 150 mg / g or more, and nitrogen adsorption specific surface area of ​​140 m 2 Carbon black of 1g or more

[0014] This rubber composition is characterized by the use of at least one of isoprene rubber and butadiene rubber in combination with a specific carbon black and a specific plasticizer, with the content of the plasticizer controlled within a specific range. By using this rubber composition, a seismic isolation rubber laminate with excellent hardening suppression effect can be obtained.

[0015] The reason why the above-mentioned excellent effects are obtained with this rubber composition is not entirely clear, but the inventors speculate as follows: A specific plasticizer with a small molecular weight penetrates between the polymer structures of isoprene rubber and / or butadiene rubber. In addition, in compounds generally containing carbon black, an insoluble component called carbon gel is formed. This is presumed to be formed by the reaction between polymer radicals generated by molecular scalding during kneading and functional groups on the surface of the carbon black. While the formation of a network structure provides a reinforcing effect, it is also presumed to promote the hardening phenomenon. Therefore, the inventors speculate that the synergistic effect of the specific plasticizer and carbon black coats the surface of the carbon black with the plasticizer, reducing the amount of carbon gel generated while finely dispersing it and inhibiting the crystallization of the polymer, thereby keeping the crystallinity of the polymer low and effectively suppressing the hardening phenomenon.

[0016] The rubber composition and other related details will be explained below.

[0017] (A) At least one of isoprene rubber and butadiene rubber This rubber composition contains at least one of isoprene rubber (IR) and butadiene rubber (BR). In this rubber composition, from the viewpoint of suppressing the hardening phenomenon that occurs during high deformation, it is particularly important to use isoprene rubber (IR) and / or butadiene rubber (BR) among the various rubber components.

[0018] (Isoprene rubber (IR)) The isoprene rubber (IR) used in this rubber composition may be any isoprene rubber (IR) that is conventionally known in the art. Isoprene rubber (IR) is a rubber obtained by polymerizing isoprene as a raw material monomer, and can be obtained, for example, by polymerizing isoprene using a Ziegler catalyst or an alkyllithium initiator.

[0019] The microstructure of isoprene rubber (IR) is not particularly limited, but the content of cis-1,4 linkage units can be, for example, 90% by mass or more, 94% by mass or more, or 96% by mass or more.

[0020] Mooney viscosity (ML) of isoprene rubber (IR) 1+4 The temperature (100°C) is not particularly limited, but for example, it is around 50-200°C, 60-150°C, or 70-100°C.

[0021] (Butadiene Rubber (BR)) The butadiene rubber (BR) used in this rubber composition may be any butadiene rubber (BR) that is conventionally known in the art. Butadiene rubber (BR) is a rubber obtained by polymerizing butadiene as a raw material monomer, and can be obtained, for example, by polymerizing butadiene using a Ziegler catalyst or an alkyllithium initiator.

[0022] The microstructure of butadiene rubber (BR) is not particularly limited, but low-cis-BR with a cis-1,4 bond unit content of 50% by mass or less, for example, 30-40% by mass, or high-cis-BR with 90% by mass or more, can be used as appropriate.

[0023] Butadiene rubber (BR) Mooney viscosity (ML 1+4 (100°C) is not particularly limited, but for example, it is around 30-60, 30-55, or 30-50.

[0024] The above Mooney viscosity is measured in accordance with the provisions of JIS K6300-1:2013, using an L-shaped rotor, with a preheating time of 1 minute, rotor rotation time of 4 minutes, and a test temperature of 100°C.

[0025] Examples of commercially available isoprene rubber (IR) and butadiene rubber (BR) include products from companies such as Zeon Corporation, UBE Elastomers, ENEOS Materials, and Asahi Kasei Corporation.

[0026] Furthermore, it is preferable that the rubber composition uses a rubber component mainly composed of isoprene rubber (IR) and / or butadiene rubber (BR). The term "main component" above means a component that accounts for 55% by mass or more of the total amount (100% by mass) of rubber components contained in the rubber composition. Therefore, it is preferable that the content of isoprene rubber (IR) and / or butadiene rubber (BR) in the total amount (100% by mass) of rubber components contained in the rubber composition be 55% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and may also be 80% by mass or more, 90% by mass or more, 95% by mass or more, or 100% by mass.

[0027] This rubber composition may optionally contain rubbers other than isoprene rubber (IR) and butadiene rubber (BR). Examples of such rubbers include, but are not limited to, natural rubber (NR), styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), and diene rubbers such as butyl rubber (IIR). These may be used individually or in combination of two or more.

[0028] Furthermore, in one embodiment of the rubber composition, it is preferable that 55% or more by mass of the total amount (100% by mass) of rubber components contained in the rubber composition is isoprene rubber (IR), and the isoprene rubber (IR) content may be 60% or more by mass, 70% or more by mass, 80% or more by mass, 90% or more by mass, 95% or more by mass, or 100% by mass of the total amount (100% by mass) of rubber components contained in the rubber composition.

[0029] (B) Plasticizer The plasticizer used in this rubber composition is important to have a molecular weight within a specific range of 300 to 900, from the viewpoint of suppressing the hardening phenomenon that occurs during high deformation. From the same viewpoint, a plasticizer with a molecular weight of 350 to 850 is preferred. If the molecular weight of the plasticizer is outside the above range, the effect of suppressing the hardening phenomenon that occurs during high deformation tends to be insufficient.

[0030] Incidentally, the molecular weight of the plasticizer (B) can be appropriately set within the above range. For example, it may be a plasticizer having a molecular weight of 300 to 500, a plasticizer having a molecular weight of 300 to 400, or the like.

[0031] Preferred examples of the plasticizer include ester plasticizers from the viewpoint of suppressing the hardening phenomenon that occurs during high deformation. Examples of ester plasticizers include adipic acid ester plasticizers, phosphoric acid ester plasticizers, sebacic acid ester plasticizers, phthalic acid ester plasticizers, and the like. Among these, adipic acid ester plasticizers are preferred.

[0032] Examples of adipic acid ester plasticizers include dimethyl adipate, diethyl adipate, dibutyl adipate, diheptyl adipate, diisononyl adipate, dioctyl adipate, diisooctyl adipate, di(2-ethylhexyl) adipate, dinonyl adipate, diisononyl adipate, diisodecyl adipate, ditridecyl adipate, dibutylpentyl adipate, and dicyclohexyl adipate.

[0033] Other preferred examples of the plasticizer include hydrocarbon plasticizers. Examples of hydrocarbon plasticizers include paraffinic hydrocarbons, olefinic hydrocarbons, and the like. Among these, olefinic hydrocarbons are preferred.

[0034] Examples of olefinic hydrocarbons include poly-α-olefins. Poly-α-olefins include, for example, those obtained by polymerizing α-olefins having 6 to 16 carbon atoms.

[0035] More preferred plasticizers include dioctyl adipate (DOA), diisodecyl adipate (DIDA), diisononyl adipate (DIN), poly-α-olefin (PAO), and the like. Among these, even more preferred are dioctyl adipate (DOA), diisodecyl adipate (DIDA), and diisononyl adipate (DIN).

[0036] From the perspective of suppressing the hardening phenomenon that occurs during high deformation, it is important that the plasticizer content is in the range of 10 to 30 parts by mass with respect to 100 parts by mass of component (A). When the plasticizer content is more than the above range, bleeding of the plasticizer tends to reduce the rubber kneading processability, the fracture properties of the vulcanized rubber, and the adhesion to metallic members. When it is less than the above range, the effect of suppressing the hardening phenomenon that occurs during high deformation tends to be insufficient.

[0037] 《(C) Carbon Black》 The (C) carbon black used in this rubber composition should, from the perspective of suppressing the hardening phenomenon that occurs during high deformation, have a DBP (dibutyl phthalate) oil absorption, iodine adsorption amount, and nitrogen adsorption specific surface area within specific ranges. The (C) carbon black used in this rubber composition should have a DBP (dibutyl phthalate) oil absorption of 100 ml / 100 g or more, an iodine adsorption amount of 150 mg / g or more, and a nitrogen adsorption specific surface area of 140 m 2 / g or more. By using carbon black that satisfies all of these three requirements, the hardening phenomenon that occurs during high deformation can be effectively suppressed. With carbon black that does not satisfy even one of these three requirements, sufficient effects cannot be obtained.

[0038] The DBP oil absorption of the carbon black is preferably 105 ml / 100 g or more, more preferably 108 ml / 100 g or more, and even more preferably 110 ml / 100 g or more. Also, although not particularly limited, for example, the DBP oil absorption of the carbon black is 150 ml / 100 g or less, preferably 145 ml / 100 g or less.

[0039] The iodine adsorption amount of the carbon black is preferably 152 mg / g or more, and may be 160 mg / g or more. Also, although not particularly limited, for example, the iodine adsorption amount of the carbon black is 200 mg / g or less, preferably 190 mg / g or less.

[0040] The nitrogen adsorption specific surface area of the carbon black is preferably 142 m 2 / g or more, and 150 m 2It may also be 190 m or more. Although not particularly limited, for example, the nitrogen adsorption specific surface area of carbon black is 190 m 2 / g or less, preferably 180 m 2 / g or less.

[0041] Incidentally, the iodine adsorption amount of carbon black is measured in accordance with JIS K6217-1 (Method A). The DBP absorption amount of carbon black is measured in accordance with JIS K6217-4. Also, the nitrogen adsorption specific surface area of the above carbon black is measured in accordance with JIS K6217-2.

[0042] The average particle size of carbon black is preferably 30 nm or less, more preferably 28 nm or less, and may also be 26 nm or less. The lower limit value of the average particle size of carbon black is not particularly limited, but is 12 nm or more. Incidentally, the average particle size of carbon black (B) can be measured by using TEM or the like.

[0043] The content of carbon black is, for example, 50 to 150 parts by mass, more preferably 55 to 125 parts by mass, still more preferably 60 to 100 parts by mass, and may also be 70 to 85 parts by mass with respect to 100 parts by mass of the component (A). When within the above range, there is a tendency for the effect of suppressing the hardening phenomenon that occurs during high deformation to be further excellent. Also, there is a tendency to improve kneading processability and suppress deterioration of scorch properties.

[0044] 《Other Optional Components》 In addition to the above components (A) to (C), this rubber composition may be blended with a vulcanizing agent, a vulcanization accelerator, an anti-aging agent, a filler, etc. within a range that does not inhibit the effects of the present invention. These may be used alone or in combination of two or more.

[0045] Incidentally, the content of the component (A) in this rubber composition is not particularly limited, but is, for example, 30 to 70% by mass, preferably 32 to 68% by mass, more preferably 34 to 65% by mass, etc. with respect to the total amount (100% by mass) of this rubber composition.

[0046] Examples of vulcanizing agents include sulfur (powdered sulfur, precipitated sulfur, insoluble sulfur). The content of the vulcanizing agent is not particularly limited, but is, for example, 0.1 to 7 parts by mass, preferably 0.3 to 6 parts by mass, and more preferably 0.5 to 5 parts by mass, per 100 parts by mass of component (A).

[0047] Examples of vulcanization accelerators include thiazole-based, sulfenamide-based, thiram-based, aldehyde ammonia-based, aldehyde amine-based, guanidine-based, and thiourea-based vulcanization accelerators. The content of the vulcanization accelerator is not particularly limited, but is, for example, 0.1 to 7 parts by mass, preferably 0.1 to 5 parts by mass, more preferably 0.3 to 4 parts by mass, and even more preferably 0.5 to 3 parts by mass, per 100 parts by mass of component (A).

[0048] Examples of thiazole-based vulcanization accelerators include dibenzothiadyl disulfide (MBTS), 2-mercaptobenzothiazole (MBT), 2-mercaptobenzothiazole sodium salt (NaMBT), and 2-mercaptobenzothiazole zinc salt (ZnMBT). The content of the thiazole-based vulcanization accelerator is not particularly limited, but is, for example, 0.1 to 7 parts by mass, preferably 0.3 to 6 parts by mass, and more preferably 0.5 to 5 parts by mass, per 100 parts by mass of component (A).

[0049] Examples of sulfenamide-based vulcanization accelerators include N-oxydiethylene-2-benzothiazolylsulfenamide (NOBS), N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), N-t-butyl-2-benzothiazolylsulfenamide (BBS), and N,N'-dicyclohexyl-2-benzothiazolylsulfenamide. The content of the sulfenamide-based vulcanization accelerator is not limited, but is, for example, 0.1 to 3 parts by mass, preferably 0.3 to 2.5 parts by mass, and more preferably 0.5 to 2 parts by mass, per 100 parts by mass of component (A).

[0050] Examples of thiram-based vulcanization accelerators include tetramethylthiram disulfide (TMTD), tetraethylthiram disulfide (TETD), tetrabutylthiram disulfide (TBTD), tetrakis(2-ethylhexyl)thiram disulfide (TOT), and tetrabenzylthiram disulfide (TBzTD). The content of the thiram-based vulcanization accelerator is not particularly limited, but is, for example, 0.1 to 5 parts by mass, preferably 0.3 to 4 parts by mass, and more preferably 0.5 to 3 parts by mass, per 100 parts by mass of component (A).

[0051] Examples of vulcanization aids include zinc oxide, zinc oxide (ZnO), stearic acid, and magnesium oxide. The content of the vulcanization aid is not particularly limited, but is, for example, 1 to 15 parts by mass, preferably 2 to 13 parts by mass, and more preferably 3 to 10 parts by mass, per 100 parts by mass of component (A).

[0052] Examples of anti-aging agents include carbamate-based anti-aging agents, phenylenediamine-based anti-aging agents, phenol-based anti-aging agents, diphenylamine-based anti-aging agents, quinoline-based anti-aging agents, imidazole-based anti-aging agents, and waxes. The content of the anti-aging agent is not particularly limited, but is, for example, 0.1 to 15 parts by mass, preferably 0.5 to 12 parts by mass, and more preferably 1 to 10 parts by mass, per 100 parts by mass of component (A).

[0053] Examples of fillers include silica, talc, calcium carbonate, carbon fibers, and carbon nanotubes. Among these, calcium carbonate is preferred from the viewpoint of improving the effects of the present invention.

[0054] As the calcium carbonate, any calcium carbonate conventionally known in the art can be used as appropriate. Although not particularly limited, from the viewpoint of significantly achieving the effects of the present invention, calcium carbonate that has undergone surface treatment such as hydrophobic treatment may be used. Specifically, for example, stearic acid-treated calcium carbonate, rosin acid-treated calcium carbonate, lignin-treated calcium carbonate, fatty acid quaternary ammonium salt-treated calcium carbonate, etc. may be used.

[0055] The average particle diameter (average primary particle diameter) of calcium carbonate is not limited to the following, but is for example 0.01 to 0.2 μm, preferably 0.02 to 0.19 μm, and more preferably 0.03 to 0.18 μm. The average particle diameter (average primary particle diameter) can be calculated using a scanning transmission electron microscope. The BET specific surface area of ​​calcium carbonate is not limited to the following, but is for example 10 to 80 m². 2 The value is / g, preferably 15 to 75m 2 / g, more preferably 20 to 60m 2 The value is / g. The BET specific surface area of ​​calcium carbonate can be measured, for example, by degassing the sample at 200°C for 15 minutes and then using a BET specific surface area measuring device (Microdata, 4232-II) with a mixed gas (N2: 70%, He: 30%) as the adsorbed gas. The amount of DBP (dioctyl phthalate) absorbed by calcium carbonate is not limited to the following, but is for example 10 to 80 cc / 100g, preferably 15 to 75 cc / 100g, and more preferably 20 to 60 cc / 100g.

[0056] The filler content is not particularly limited, but is 20 to 150 parts by mass, preferably 30 to 140 parts by mass, and more preferably 40 to 130 parts by mass, per 100 parts by mass of component (A). The calcium carbonate content is not particularly limited, but is, for example, 10 to 80 parts by mass, preferably 15 to 75 parts by mass, and more preferably 20 to 70 parts by mass, per 100 parts by mass of component (A).

[0057] (Method for preparing the rubber composition) The rubber composition can be obtained by kneading components (A) to (C), and other components as needed, using a kneader, planetary mixer, mixing roll, twin-screw agitator, etc. For example, the rubber composition can be prepared by kneading the materials excluding the vulcanizing agent and vulcanization accelerator, and then adding the vulcanizing agent and vulcanization accelerator and kneading.

[0058] (Method for manufacturing seismic isolation rubber laminates) Various known methods can be used as appropriate when manufacturing seismic isolation rubber laminates. Specifically, for example, a method can be used in which the rubber composition is placed in the presence of upper and lower mounting plates together with a metal plate using a vulcanizing mold, and a rubber block is vulcanized and molded so that a rubber layer is interposed between the metal plates and the rubber is integrally vulcanized and bonded. Alternatively, a seismic isolation rubber laminate can be manufactured by alternately laminating and bonding metal plates and rubber layers formed from the rubber composition using a suitable adhesive to integrate them.

[0059] For example, to obtain the seismic isolation rubber laminate 10 shown in Figure 1, one method is to knead a predetermined rubber composition using a closed-type kneader or the like, then use a vulcanizing mold to place the predetermined rubber composition in the presence of a predetermined metal plate 14 or upper and lower mounting plates 18, 20 together with it, and vulcanize the rubber block 12, thereby creating a structure in which a rubber layer 16 is interposed between the metal plates 14, 14 and integrally vulcanized and bonded. Alternatively, a method can be employed in which the metal plate 14 and the rubber layer 16 formed from the rubber composition are alternately laminated and bonded using a suitable adhesive to form a laminate.

[0060] In the seismic isolation rubber laminate of the present invention, iron plates or steel plates with excellent compression resistance can be suitably used as the metal plate 14, but other metal materials may also be used, and even hard plastic plates can be used as long as they have excellent compression resistance.

[0061] Furthermore, the overall shape of the seismic isolation rubber laminate 10 is not particularly limited, and an appropriate shape can be adopted depending on the installation method. For example, in the planar form, in addition to a square or disc shape, polygonal shapes such as an ellipse, pentagon, or hexagon can be used. Also, the number of layers of metal plates 14 and rubber layers 16 can be appropriately determined according to the application of the seismic isolation rubber laminate.

[0062] Next, examples will be described together with comparative examples. However, the present invention is not limited to these examples unless it exceeds the essence of the invention.

[0063] First, prior to the examples and comparative examples, components (A) to (C) shown below were prepared. The numerical values ​​for each material shown below were measured based on the measurement method described above.

[0064] <(A) Components> - Isoprene rubber (A1) - Butadiene rubber (A2)

[0065] <Component (B)> ・Plasticizer (B1): Dioctyl adipate (DOA: Molecular weight 370) ・Plasticizer (B2): Diisodecyl adipate (DIDA: Molecular weight 800) ・Plasticizer (B3): Diisononyl adipate (DINA: Molecular weight 400) ・Plasticizer (B4): Poly-α-olefin (PAO: Molecular weight 700)

[0066] <Component (B')> ・Plasticizer (B'1): Dibutyl phthalate (molecular weight 248) ・Plasticizer (B'2): Adipic acid-based polyester (molecular weight 1100)

[0067] <(C) Components> Carbon black (C1) (Iodine adsorption capacity 163 mg / g, Nitrogen adsorption specific surface area 152 m²) 2 ( / g, DBP oil absorption capacity 130 ml / 100 g) ・Carbon black (C2) (iodine adsorption capacity 185 mg / g, nitrogen adsorption specific surface area 173 m²) 2 / g, DBP oil absorption 112ml / 100g)

[0068] <(C') component> Carbon black (C'1) (iodine adsorption capacity 119 mg / g, nitrogen adsorption specific surface area 108 m²) 2 ( / g, DBP oil absorption capacity 115 ml / 100g) ・Carbon black (C'2) (iodine adsorption capacity 104 mg / g, nitrogen adsorption specific surface area 99 m²) 2 ( / g, DBP oil absorption capacity 129 ml / 100g) ・Carbon black (C'3) (iodine adsorption capacity 86 mg / g, nitrogen adsorption specific surface area 84 m²) 2 / g, DBP oil absorption 75ml / 100g)

[0069] [Examples 1-6, Comparative Examples 1-5] The components shown in Table 1 below were blended in the proportions shown in the same table to prepare the target rubber composition, and the following tests were conducted. Specifically, the rubber composition was prepared through three steps: a first step of mixing isoprene rubber (or butadiene rubber) and calcium carbonate to prepare a masterbatch; a second step of adding materials excluding the vulcanizing agent (sulfur) and vulcanization accelerator to the masterbatch and kneading; and a third step of adding the vulcanizing agent and vulcanization accelerator and kneading. The first step was performed by repeating kneading at 130°C for 10 minutes three times using a kneader. In the second step, materials excluding the vulcanizing agent and vulcanization accelerator were added to the masterbatch prepared in the first step and kneaded at 130°C for 10 minutes using a kneader. In the third step, kneading was performed at 40°C for 10 minutes using a mixing roll.

[0070] [Hardening Characteristics Evaluation Test] The hardening characteristics of the rubber composition were evaluated using the apparatus shown in Figure 2. Specifically, a two-component adhesive for rubber was applied to predetermined locations (adhesion locations for sample 21) of two blast-treated metal fittings 22 (size 140 mm x 80 mm, thickness 9 mm). Then, the rubber composition of the example or comparative example was sandwiched between the two metal fittings 22 and dried. This was then hot-pressed at 100°C for 10 minutes to produce a sample (size 70 mm x 80 mm, thickness 5 mm) 21. The apparatus was then vibrated in the direction of the arrow, and the dynamic shear characteristics were evaluated based on the load-strain loop curve shown in Figure 3. Specifically, the above apparatus was subjected to vibration excitation simulating a major earthquake (shear strain rate: 200% (200% of sample thickness), frequency (f): 0.33 Hz, measurement temperature: 20°C) using a vibration exciter (Washinomiya Seisakusho Co., Ltd., DYNAMIC SERVO), an input signal oscillator (Yokogawa Electric Corporation, Synthesized Function Generator FC320), and an output signal processor (Ono Sokki Co., Ltd., Portable FFT Analyzer CF-3200). Based on the load-strain loop curve shown in Figure 3, the difference in elastic modulus (β / α) in each strain region was calculated from the load change rate (α: Δ100% / 10%, β: Δ200% / 100%) at 10% and 100% strain, and at 100% and 200% strain. The difference in elastic modulus calculated above was evaluated according to the following criteria. The results are shown in Table 1. (Evaluation Criteria) ◎ (very good) ... Difference in elastic modulus is less than 1.2 〇 (good) ... Difference in elastic modulus is 1.2 or more but less than 1.8 × (poor) ... Difference in elastic modulus is 1.8 or more

[0071]

[0072] From the results in Table 1 above, it can be seen that the sample of the example satisfies the requirements of the present invention, the hardening characteristics evaluation results are good, and the hardening phenomenon that occurs at high displacement can be effectively suppressed.

[0073] In contrast, the results in Table 1 above show that the comparative examples do not satisfy the requirements of the present invention, resulting in poor hardening characteristic evaluation and making it difficult to effectively suppress the hardening phenomenon that occurs at high displacement. Specifically, if at least one of the iodine adsorption amount, nitrogen adsorption specific surface area, and DBP oil absorption amount of carbon black does not satisfy the requirements of the present invention (Comparative Examples 1-3), it is difficult to effectively suppress the hardening phenomenon that occurs at high displacement. Furthermore, if the content of plasticizers with a molecular weight of 300-900 does not satisfy the requirements of the present invention (Comparative Example 4), it is difficult to effectively suppress the hardening phenomenon that occurs at high displacement. Moreover, if the molecular weight of the plasticizer does not satisfy the provisions of the present invention (Comparative Examples 5 and 6), it is difficult to effectively suppress the hardening phenomenon that occurs at high displacement.

[0074] Based on the above, the requirements of the present invention are met, namely: (A) at least one of isoprene rubber and butadiene rubber, (B) a plasticizer with a molecular weight of 300 to 900, and (C) a DBP oil absorption amount of 100 ml / 100 g or more, an iodine adsorption amount of 150 mg / g or more, and a nitrogen adsorption specific surface area of ​​140 m². 2 It can be seen that by including carbon black of 1g or more and setting the content of component (B) to 10 to 30 parts by mass per 100 parts by mass of component (A), the hardening phenomenon that occurs at high displacement can be effectively suppressed.

[0075] While the above embodiments illustrate specific forms of the present invention, these embodiments are merely illustrative and should not be interpreted restrictively. Various modifications that are obvious to those skilled in the art are intended to fall within the scope of the present invention.

[0076] The seismic isolation rubber laminate of the present invention can exhibit excellent functionality as a seismic isolation rubber laminate used in large structures such as high-rise buildings and bridges.

[0077] 10 Seismic isolation rubber laminate 12 Rubber block 14 Metal plate 16 Rubber layer 18 Upper mounting plate 20 Lower mounting plate

Claims

1. A rubber composition for seismic isolation rubber laminates used in the rubber layer of a seismic isolation rubber laminate, comprising the following components (A) to (C), wherein the content of component (B) is 10 to 30 parts by mass per 100 parts by mass of component (A). (A) At least one of isoprene rubber and butadiene rubber (B) Plasticizer with a molecular weight of 300 to 900 (C) DBP oil absorption of 100 ml / 100 g or more, iodine adsorption of 150 mg / g or more, and nitrogen adsorption specific surface area of ​​140 m 2 Carbon black of 1g or more 2. The rubber composition for seismic isolation rubber laminate according to claim 1, wherein component (B) is an adipic acid ester plasticizer having a molecular weight of 300 to 900.

3. The rubber composition for seismic isolation rubber laminate according to claim 1 or 2, wherein the content of component (C) is 30 to 150 parts by mass per 100 parts by mass of component (A).

4. The rubber composition for seismic isolation rubber laminate according to any one of claims 1 to 3, wherein the component (A) above contains isoprene rubber, and the isoprene rubber content is 70% by mass or more of the total amount of rubber components contained in the rubber composition for seismic isolation rubber laminate.

5. A seismic isolation rubber laminate having a rubber layer made of the seismic isolation rubber composition for seismic isolation rubber laminates according to any one of claims 1 to 4, and a layer made of a metal plate.

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