Shock isolation rubber laminate

Abstract

A vibration-damping rubber laminate with excellent damping characteristics is provided. The vibration-damping rubber laminate has a rubber layer formed from a vulcanizate of a rubber composition for vibration-damping rubber laminate containing components (A) and (B), wherein the number of aggregates consisting of three or more calcium carbonate particles linked together in any 1μm × 1μm square region of a scanning transmission electron microscope image obtained by photographing the rubber layer at 150,000x magnification is in the range of 5 to 15, wherein (A) isoprene rubber and at least one butadiene rubber, and (B) calcium carbonate.

Description

Technical Field

[0001] This invention relates to seismic isolation rubber laminates. More specifically, it relates to seismic isolation rubber laminates for supporting civil and architectural structures. Background Technology

[0002] In the past, seismic isolation rubber laminates (rubber supports) have been used in the support of structures in the fields of civil engineering and architecture. Seismic isolation rubber laminates are, for example, structures configured between the upper and lower structures of buildings or other structures.

[0003] Seismic isolation rubber laminates typically have a laminated structure composed of alternating layers of rigid plates, such as metal plates, and rubber layers. Specifically, for example, ... Figure 1 As shown, the seismic isolation rubber laminate 10 has a structure in which multiple metal plates 14, which serve as rigid plates, are embedded in the rubber block 12 at predetermined intervals, and the metal plates 14 and the rubber block 12 portions, i.e., the rubber layers 16, located between these metal plates 14 are alternately and integrally laminated. Furthermore, it is configured such that a metal upper mounting plate 18 and a lower mounting plate 20 are respectively fixed to the upper and lower parts of the rubber block 12. If these seismic isolation rubber laminates are installed in the foundation of a building, the shaking caused by an earthquake will not be directly transmitted to the building, the shaking of the upper floors will be mitigated, and the shaking period will be lengthened, achieving the desired seismic isolation effect.

[0004] Existing technical documents Patent documents Patent Document 1: Japanese Patent No. 4120602. Summary of the Invention

[0005] The problem that the invention aims to solve In the past, various studies have been conducted from the perspective of improving the damping characteristics of seismic isolation rubber laminates. However, in reality, the correlation between the dispersion morphology of fillers in the rubber layers of seismic isolation rubber laminates and damping characteristics, especially the correlation between the dispersion morphology of calcium carbonate and damping characteristics, has not been fully studied.

[0006] The present invention was made in view of the following circumstances, and provides a vibration isolation rubber laminate with excellent damping characteristics.

[0007] means for solving problems The inventors of this invention, starting from the viewpoint of improving various properties of the vibration isolation rubber laminate, especially the damping properties, focused on the dispersion morphology of calcium carbonate in the polymer matrix of isoprene rubber and / or butadiene rubber during the process of repeatedly studying the combination of polymer components and filler components.

[0008] In the course of repeated and in-depth research based on this viewpoint, the inventors of this invention have discovered new insights into the correlation between the dispersion morphology of calcium carbonate and its attenuation characteristics. Specifically, previously, to improve various properties, it was generally considered preferable to increase the dispersibility of calcium carbonate in the polymer matrix, i.e., to minimize the proportion of particle aggregates. However, the inventors of this invention have newly discovered that in the dispersion morphology of calcium carbonate in isoprene rubber and / or butadiene rubber polymer matrices, as the dispersibility increases, the attenuation characteristics are actually hindered.

[0009] Based on this new insight, the inventors of this invention have conducted further research and found that by having the particles of calcium carbonate in a specific dispersion form, i.e., three or more calcium carbonate particles in a connected state, and by controlling the number of aggregates formed by connecting three or more calcium carbonate particles within a specific range, the damping characteristics of the rubber layer in the seismic isolation rubber laminate can be effectively improved.

[0010] That is, the main idea of ​​the present invention is the following [1]~[4]. [1] A vibration-damping rubber laminate has a rubber layer formed from a vulcanizate of a rubber composition for vibration-damping rubber laminate containing components (A) and (B) below, wherein the number of aggregates consisting of three or more calcium carbonate particles linked together in any 1 μm × 1 μm square region of a scanning transmission electron microscope image of the rubber layer obtained by taking a photograph at 150,000x magnification is in the range of 5 to 15. (A) At least one of isoprene rubber and butadiene rubber, (B) Calcium carbonate. [2] According to the vibration isolation rubber laminate described in [1], the number of aggregates formed by connecting three or more calcium carbonate particles is in the range of 6 to 10. [3] According to the vibration isolation rubber laminate described in [1] or [2], the content of component (B) is 25 to 80 parts by mass relative to 100 parts by mass of component (A). [4] The vibration isolation rubber laminate according to any one of [1] to [3], wherein isoprene rubber is included as the (A) component, and the content of the isoprene rubber is 70% by mass or more relative to the total amount of rubber components contained in the rubber composition for the vibration isolation rubber laminate.

[0015] Invention Effects According to the present invention, a vibration-damping rubber laminate with excellent damping characteristics can be provided. Attached Figure Description

[0016] Figure 1 This is an illustrative diagram representing a representative example of a seismic isolation rubber laminate.

[0017] Figure 2 This is a schematic diagram of the apparatus used for carrying out the evaluation method described in the embodiments.

[0018] Figure 3 It is a graph showing the load-strain loop curve in the evaluation method described in the embodiments.

[0019] Figure 4 This is a diagram showing a scanning transmission electron microscope image of Example 1.

[0020] Figure 5 This is a diagram representing the element mapping image of Example 1.

[0021] Figure 6 This is a magnified image (a 1μm × 1μm square area) of the scanning transmission electron microscope image of Example 1. Detailed Implementation

[0022] Next, embodiments of the present invention will be described in detail. However, the present invention is not limited to these embodiments.

[0023] In this specification, "X or / and Y (X and Y are arbitrary configurations)" means at least one of X and Y, and refers to only X, only Y, or X and Y.

[0024] Furthermore, regarding the numerical ranges described in stages in this specification, the upper or lower limit of a certain stage's numerical range can be arbitrarily combined with the upper or lower limit of the numerical ranges of other stages. Additionally, the upper or lower limit of the numerical range described in this specification can also be replaced with the values ​​shown in the embodiments.

[0025] The vibration-damping rubber laminate (hereinafter, sometimes referred to as "this rubber laminate") according to one embodiment of the present invention is characterized in that it is a vibration-damping rubber laminate having a rubber layer formed by a vulcanizate of a vibration-damping rubber laminate rubber composition (hereinafter, sometimes referred to as "this rubber composition") containing the following components (A) and (B), wherein the number of aggregates of three or more calcium carbonate particles connected together in any 1 μm × 1 μm square area of ​​a scanning transmission electron microscope image of the rubber layer obtained by taking the image at a magnification of 150,000 times is in the range of 5 to 15.

[0026] (A) At least one of isoprene rubber and butadiene rubber (B) Calcium carbonate According to this rubber laminate, in the rubber layer formed by the vulcanizate of a rubber composition comprising at least one of isoprene rubber and butadiene rubber and calcium carbonate, the calcium carbonate particles form a different dispersion morphology than in the past, thus exhibiting excellent attenuation characteristics.

[0027] Specifically, in any 1μm × 1μm square region of a scanning transmission electron microscope image obtained by photographing a rubber layer composed of a vulcanizate of a rubber composition containing at least one of isoprene rubber and butadiene rubber and calcium carbonate at a magnification of 150,000x, excellent attenuation characteristics can be obtained when the number of aggregates formed by linking three or more calcium carbonate particles is in the range of 5 to 15. If the number of aggregates is outside the above range, the excellent attenuation characteristics of the present invention cannot be obtained. For example, as is conventionally considered preferred, when there are almost no aggregates, for example, when the number of aggregates dispersed is less than 5, the excellent attenuation characteristics of the present invention cannot be obtained.

[0028] Furthermore, in a preferred embodiment of this rubber laminate, from the viewpoint of exhibiting particularly excellent attenuation characteristics, it is preferable to set the number of the above-mentioned aggregates to a range of 6 to 12 or to a range of 6 to 10.

[0029] Furthermore, there is no particular limitation on the number of calcium carbonate particles forming the above-mentioned aggregates, as long as there are three or more. For example, the number of calcium carbonate particles forming the above-mentioned aggregates is about 3 to 12 or 3 to 10. In one embodiment of the present invention, for example, the number of aggregates formed by linking 3 to 12 calcium carbonate particles is in the range of 5 to 15.

[0030] The reason for achieving the aforementioned excellent effects through this rubber laminate is not yet clear, but the inventors of this invention speculate that, in order to exhibit excellent damping properties, it is necessary to effectively represent frictional force. In this invention, in a polymer matrix comprising at least one of isoprene rubber and butadiene rubber, frictional force is significantly increased by the mutual friction of aggregates containing three or more calcium carbonate particles. Furthermore, the interparticle attraction of the calcium carbonate particles constituting the aggregates and the mutual friction between the calcium carbonate particles and specific polymer components complement each other, further significantly increasing the frictional force, thereby obtaining excellent damping characteristics. Moreover, if the calcium carbonate dispersion is poor or the number of aggregates is too large, there is a tendency to make it difficult to exhibit frictional damping; conversely, if the dispersion is too good, the performance of frictional damping requires a certain displacement. With this in mind, in this invention, it is speculated that by controlling the number of specific aggregates within a specific range, the frictional damping effect can be synergistically expressed, thus obtaining excellent damping characteristics.

[0031] Furthermore, the number of the aforementioned aggregates can be determined using conventional methods as described below.

[0032] That is, a smooth surface of the rubber layer is made using a slicer, and a 1μm × 1μm square area is identified in a scanning transmission electron microscope image taken at 150,000x magnification. The area is then visually observed to measure the number of aggregates formed by three or more calcium carbonate particles linked together.

[0033] Specifically, for example, firstly, a scanning transmission electron microscope (STEM) image is obtained by observing the rubber layer at a magnification of 150,000x. Next, an elemental mapping image is obtained using an energy-dispersive X-ray spectrometer attached to the STEM, and Ca atoms and other components from calcium carbonate are detected, thereby determining the calcium carbonate within the microscope image. Then, the elemental mapping image is compared with a magnified version of the electron microscope image to visually measure the number of aggregates contained in a 1 μm × 1 μm square region within the electron microscope image.

[0034] Furthermore, in this specification, "an aggregate of three or more calcium carbonate particles connected together" observed in a scanning transmission electron microscope image refers to an aggregate that includes at least a first calcium carbonate particle, a second calcium carbonate particle in contact with the first calcium carbonate particle, and a third calcium carbonate particle in contact with at least one of the first and second calcium carbonate particles.

[0035] Specifically, it is an aggregate of calcium carbonate particles whose outer contours abut against the outer contours of the first calcium carbonate particles and the second calcium carbonate particles, and which includes at least a third calcium carbonate particle that abuts against at least one of the first and second calcium carbonate particles.

[0036] Furthermore, the "aggregate of three or more calcium carbonate particles linked together" observed in scanning transmission electron microscopy images refers to situations where, due to the interparticle attraction of calcium carbonate particles, not only the particles are in contact with each other, but also the particles are within 20 nm in distance. That is, when the distance between any calcium carbonate particle and other calcium carbonate particles is within 20 nm, they can be considered to be in contact through chemical and physical interparticle attraction. Therefore, an aggregate comprising at least a first calcium carbonate particle, a second calcium carbonate particle within 20 nm of the first calcium carbonate particle, and a third calcium carbonate particle within 20 nm of at least one of the first and second calcium carbonate particles can be considered an "aggregate of three or more calcium carbonate particles linked together."

[0037] More specifically, when the shortest straight-line distance between the outlines of any calcium carbonate particle and the outlines of other calcium carbonate particles is within 20 nm, or more specifically, when the shortest straight-line distance between any point on the outline of any calcium carbonate particle and any point on the outline of other calcium carbonate particles is within 20 nm, the calcium carbonate particles can be considered to be in contact with each other, and therefore can be considered as "an aggregate of three or more calcium carbonate particles connected together".

[0038] The following provides a detailed description of the rubber composition and the rubber laminate.

[0039] (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 exhibiting excellent damping properties, isoprene rubber (IR) and / or butadiene rubber (BR) are particularly important among the various rubber components.

[0040] (Isoprene rubber (IR)) The isoprene rubber (IR) used in this rubber composition may appropriately be any isoprene rubber previously known in the art. Isoprene rubber (IR) is a rubber obtained by polymerizing isoprene as a raw material monomer, for example, by polymerizing isoprene using a Ziegler catalyst, an alkyl lithium initiator, etc.

[0041] There are no particular restrictions on the microstructure of isoprene rubber (IR), but the content of cis-1,4 bond units can be, for example, 90% or more by mass, 94% or more by mass, 96% or more by mass, etc.

[0042] Mooney viscosity (ML) of isoprene rubber (IR) 1+4 (100℃) There is no special limit, for example, it is around 50~200, 60~150, 70~100.

[0043] (Butadiene rubber (BR)) The butadiene rubber (BR) used in this rubber composition may be any butadiene rubber (BR) previously known in the art. Butadiene rubber (BR) is a rubber obtained by polymerizing butadiene as a monomer, for example, by polymerizing butadiene using a Ziegler catalyst, an alkyl lithium initiator, etc.

[0044] The microstructure of butadiene rubber (BR) is not particularly limited. It is appropriate to use low cis-BR with a content of less than 50% by mass, such as about 30 to 40% by mass, or high cis-BR with a content of more than 90% by mass.

[0045] Mooney viscosity (ML) of butadiene rubber (BR) 1+4 (100℃) There is no special limit, for example, it is around 30~60, 30~55, or 30~50.

[0046] The Mooney viscosity was measured according to JIS K6300-1:2013, using an L-shaped rotor, under the conditions of a preheating time of 1 minute, a rotor rotation time of 4 minutes, and a test temperature of 100°C.

[0047] Commercially available products such as isoprene rubber (IR) and butadiene rubber (BR) include those from companies such as Zeon Corporation, UBE Elastomer, ENEOS Materials, and Asahi Kasei Corporation.

[0048] In addition, this rubber composition preferably uses a rubber component with isoprene rubber (IR) and / or butadiene rubber (BR) as the main components.

[0049] The term "main component" refers to a component that accounts for 55% or more of the total amount (100% by mass) of the rubber components contained in this rubber composition. Therefore, the content of isoprene rubber (IR) and / or butadiene rubber (BR) in the total amount (100% by mass) of the rubber components contained in this rubber composition is preferably 55% or more by mass, more preferably 60% or more by mass, even more preferably 70% or more by mass, and may also be 80% or more by mass, 90% or more by mass, 95% or more by mass, or 100% by mass.

[0050] 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, diene-based rubbers such as natural rubber (NR), styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), and butyl rubber (IIR). They may be used alone or in combination of two or more.

[0051] In addition, as one embodiment of the rubber composition, it is preferable that 55% or more of the total amount (100% by mass) of the rubber components contained in the rubber composition is composed of isoprene rubber (IR). Alternatively, the content of isoprene rubber (IR) may be 60% or more, 70% or more, 80% or more, 90% or more, 95% or more, or 100% by mass of the total amount (100% by mass) of the rubber components contained in the rubber composition.

[0052] (B) Calcium Carbonate Importantly, this rubber composition contains calcium carbonate, particularly, in various fillers, along with component (A). Moreover, as mentioned above, it is important that the calcium carbonate has a specific dispersion morphology.

[0053] As calcium carbonate, calcium carbonate conventionally known in the art can be appropriately used. While not particularly limited, from the viewpoint of significantly maximizing the effects of the present invention, for example, calcium carbonate that has undergone surface treatment such as hydrophobic treatment can be used. Specifically, for example, calcium carbonate treated with stearic acid, calcium carbonate treated with rosin acid, calcium carbonate treated with lignin, calcium carbonate treated with quaternary ammonium salts of fatty acids, etc., can be used.

[0054] The average particle size (average primary particle size) of calcium carbonate is, for example, 0.01 to 0.2 μm, preferably 0.02 to 0.19 μm, more preferably 0.03 to 0.18 μm, but is not limited thereto. Furthermore, the average particle size (average primary particle size) can be calculated using a scanning transmission electron microscope.

[0055] The BET specific surface area of ​​calcium carbonate is, for example, 10~80 m². 2 / g, preferably 15~75m 2 / g, more preferably 20~60m 2 / g, but not limited to this. The BET specific surface area of ​​calcium carbonate can be determined, for example, as follows: after degassing the sample at 200°C for 15 minutes, a mixed gas (N2: 70%, He: 30%) is used as the adsorbed gas, and the BET specific surface area is measured using a BET specific surface area measuring device manufactured by Micro Data Corporation (4232-II).

[0056] The oil absorption capacity of calcium carbonate DBP (dioctyl phthalate) is, for example, 10~80cc / 100g, preferably 15~75cc / 100g, more preferably 20~60cc / 100g, but not limited thereto.

[0057] The calcium carbonate content, from the viewpoint of easily controlling the above-mentioned aggregates within a suitable range, is, for example, 10 to 80 parts by mass relative to 100 parts by mass of component (A), preferably 15 to 75 parts by mass, and more preferably 20 to 70 parts by mass.

[0058] Other arbitrary ingredients In addition to components (A) and (B) mentioned above, this rubber composition may also contain plasticizers, vulcanizing agents, vulcanization accelerators, anti-aging agents, carbon black, and other fillers, without impairing the effects of the present invention. These can be used alone or in combination of two or more.

[0059] Furthermore, the content of component (A) in this rubber composition is not limited, but is, for example, 30 to 70% by mass relative to the total amount of this rubber composition (100% by mass), preferably 32 to 68% by mass, more preferably 34 to 65% by mass, etc.

[0060] (Plasticizer) Examples of plasticizers include adipate-based plasticizers, phosphate-based plasticizers, sebacic acid ester-based plasticizers, and phthalate-based plasticizers. Among these, adipate-based plasticizers are preferred.

[0061] Examples of adipate ester plasticizers include dimethyl adipate, diethyl adipate, dibutyl adipate, diheptyl adipate, diisononyl adipate, dioctyl adipate, di-2-ethylhexyl adipate, dinonyl adipate, diisononyl adipate, diisodecyl adipate, ditridecyl adipate, dibutylpentyl adipate, and dicyclohexyl adipate.

[0062] Other examples of plasticizers include hydrocarbon-based plasticizers. Examples of hydrocarbon-based plasticizers include paraffinic hydrocarbons and olefinic hydrocarbons.

[0063] As an olefinic hydrocarbon, poly-α-olefins can be listed as examples. Poly-α-olefins can be exemplified by, for example, olefinic hydrocarbons formed by polymerizing α-olefins with 6 to 16 carbon atoms.

[0064] The content of plasticizer is not particularly limited, but is, for example, 1 to 40 parts by mass relative to 100 parts by mass of component (A), preferably 5 to 35 parts by mass, and more preferably 10 to 30 parts by mass.

[0065] Examples of sulfur-forming agents include sulfur (powdered sulfur, precipitated sulfur, insoluble sulfur, etc.).

[0066] The content of the vulcanizing agent is not particularly limited, but is, for example, 0.1 to 7 parts by mass relative to 100 parts by mass of component (A), preferably 0.3 to 6 parts by mass, and more preferably 0.5 to 5 parts by mass.

[0067] Examples of vulcanization accelerators include thiazole-based, sulfenamide-based, thiuram-based, aldehyde-amine-based, guanidine-based, and thiourea-based vulcanization accelerators.

[0068] The content of the vulcanization accelerator is not particularly limited, but is, for example, 0.1 to 7 parts by mass relative to 100 parts by mass of component (A), 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.

[0069] Examples of thiazole-based vulcanization accelerators include dibenzothiazole disulfide (MBTS), 2-mercaptobenzothiazole (MBT), sodium 2-mercaptobenzothiazole (NaMBT), and zinc 2-mercaptobenzothiazole (ZnMBT). The content of the thiazole-based vulcanization accelerator is not limited, but relative to 100 parts by weight of component (A), it can be, for example, 0.1 to 7 parts by weight, preferably 0.3 to 6 parts by weight, and more preferably 0.5 to 5 parts by weight.

[0070] Examples of sulfenamide-based vulcanization accelerators include N-oxodiethylene-2-benzothiazolyl sulfenamide (NOBS), N-cyclohexyl-2-benzothiazolyl sulfenamide (CBS), N-tert-butyl-2-benzothiazolyl sulfenamide (BBS), and N,N'-dicyclohexyl-2-benzothiazolyl sulfenamide. The content of the sulfenamide-based vulcanization accelerator is not limited, but relative to 100 parts by weight of component (A), it can be, for example, 0.1 to 3 parts by weight, preferably 0.3 to 2.5 parts by weight, and more preferably 0.5 to 2 parts by weight.

[0071] 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). The content of the thiuram-based vulcanization accelerator is not limited, but relative to 100 parts by weight of component (A), it can be, for example, 0.1 to 5 parts by weight, preferably 0.3 to 4 parts by weight, and more preferably 0.5 to 3 parts by weight.

[0072] Examples of vulcanizing aids include zinc oxide, zinc oxide (ZnO), stearic acid, and magnesium oxide.

[0073] The content of the vulcanizing aid is not particularly limited, but is, for example, 1 to 15 parts by mass relative to 100 parts by mass of component (A), preferably 2 to 13 parts by mass, and more preferably 3 to 10 parts by mass.

[0074] 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.

[0075] The content of the anti-aging agent is not particularly limited, but is, for example, 0.1 to 15 parts by mass relative to 100 parts by mass of component (A), preferably 0.5 to 12 parts by mass, and more preferably 1 to 10 parts by mass.

[0076] Examples of fillers include carbon black, silica, talc, carbon fiber, and carbon nanotubes. Among these, carbon black is preferred.

[0077] As a carbon black, it is preferred to have a DBP oil absorption capacity of 100~150 ml / 100 g, an iodine adsorption capacity of 150~200 mg / g, and a nitrogen adsorption specific surface area of ​​140~200 m². 2 / g of carbon black, but not limited to this.

[0078] Furthermore, the iodine adsorption capacity of the carbon black was determined according to JIS K6217-1 (Method A). The DBP adsorption capacity of the carbon black was determined according to JIS K6217-4. In addition, the nitrogen adsorption specific surface area of ​​the above-mentioned carbon black was determined according to JIS K6217-2.

[0079] The content of the filler is not particularly limited, but is, for example, 20 to 150 parts by mass relative to 100 parts by mass of component (A), preferably 30 to 140 parts by mass, and more preferably 40 to 130 parts by mass.

[0080] (Preparation method of this rubber composition) This rubber composition can be obtained, for example, by mixing component (A), component (B), and other components as needed using a kneader, planetary mixer, mixing roller, twin-screw mixer, etc.

[0081] As described above, the characteristic of this rubber laminate is that, in any 1μm × 1μm square region of a scanning transmission electron microscope image obtained by photographing the rubber layer at 150,000x magnification, the number of aggregates formed by three or more calcium carbonate particles connected together is in the range of 5 to 15. By controlling the number of the above-mentioned aggregates within the range of 5 to 15, excellent attenuation characteristics can be achieved.

[0082] There are no particular limitations on the method of controlling the number of the above-mentioned aggregates within the above-mentioned range. For example, methods such as adjusting the number of mixing times within a certain range when preparing this rubber composition, and adjusting the mixing temperature within a certain range can be listed.

[0083] Among these methods, when preparing this rubber composition, it is preferable to adjust the number of mixing cycles within a certain range. Specifically, for example, it is preferable to adjust the number of mixing cycles of materials other than vulcanizing agents such as sulfur and vulcanization accelerators within a certain range. In addition, it is preferable to adjust the discharge temperature of the rubber after mixing within a certain range.

[0084] More specifically, the method for preparing a rubber composition involves a first step of preparing a masterbatch by mixing component (A) and component (B), a second step of adding materials other than vulcanizing agents and vulcanization accelerators to the masterbatch and mixing them, and a third step of adding vulcanizing agents and vulcanization accelerators and mixing them. In the first step, it is preferable to repeat the mixing at 100-160°C for 1-10 minutes (preferably 110-150°C for 3-8 minutes) 2-6 times (preferably 2-5 times). Furthermore, from the viewpoint of controlling the discharge temperature, in the third step, it is preferable to perform mixing at 40-110°C for 1-10 minutes (preferably 50-100°C for 3-8 minutes). For example, if the first step is performed with fewer mixing times than described above, there is a tendency for the number of aggregates to exceed the range specified in this invention, and there is a tendency for the attenuation characteristics to become insufficient. Conversely, when the first process is performed more times than the above-mentioned mixing times, there is a tendency for the number of aggregates to become less than the range specified in this invention, and there is a tendency for the attenuation characteristics to become insufficient.

[0085] (Manufacturing method of seismic isolation rubber laminate) A seismic isolation rubber laminate comprises a rubber layer made of a rubber composition and a layer made of a metal plate. Various known methods are appropriately employed in manufacturing the seismic isolation rubber laminate. Specifically, for example, a method is used where, in the presence of a metal plate or an upper mounting plate and a lower mounting plate together with the metal plate, the rubber composition is prepared, and the rubber block is vulcanized, thereby forming a structure in which the rubber layer is integrally vulcanized and bonded between the metal plates; or a suitable adhesive is used to alternately laminate and bond the metal plate and the rubber layer formed by the rubber composition to achieve integral bonding, thereby enabling the manufacture of a seismic isolation rubber laminate.

[0086] For example, in order to obtain Figure 1 The vibration-damping rubber laminate 10 shown can be constructed by the following method: after mixing a predetermined rubber composition using a closed-type mixer or the like, a predetermined rubber composition is prepared using a vulcanization molding die, either in the presence of a predetermined metal plate 14 or in the presence of an upper mounting plate 18 and a lower mounting plate 20 together with the predetermined metal plate 14, and the rubber block 12 is vulcanized and molded, thereby forming a structure in which a rubber layer 16 is integrally vulcanized and bonded between the metal plates 14. Alternatively, a suitable adhesive can be used to alternately laminate and bond the metal plates 14 and the rubber layer 16 formed from the rubber composition to form an integral laminate.

[0087] Furthermore, the metal plate 14 in the vibration isolation rubber laminate of the present invention can be made of iron plate or steel plate with excellent compression resistance, or it can be a metal plate of other metal materials. Moreover, even rigid plastic sheet or the like can be used as long as it is a sheet with excellent compression resistance.

[0088] Furthermore, the overall shape of the seismic isolation rubber laminate 10 is not particularly limited, and an appropriate shape corresponding to its installation configuration can be adopted. For example, in a planar shape, in addition to quadrilateral and circular plate shapes, polygonal shapes such as ellipses, pentagons, and hexagons can also be used. In addition, the number of layers of the metal plate 14 and the rubber layer 16 is appropriately determined according to the application of the seismic isolation rubber laminate.

[0089] Example Next, embodiments will be described together with comparative examples. However, the present invention is not limited to these embodiments without departing from its spirit.

[0090] (Example 1) The target rubber composition is prepared by combining the components shown in Table 1 (described later) in the proportions shown in the table. That is, the rubber composition is prepared by a first step of preparing a masterbatch by mixing isoprene rubber and calcium carbonate, a second step of adding materials other than vulcanizing agent (sulfur) and vulcanization accelerator to the masterbatch and mixing them, and a third step of adding vulcanizing agent and vulcanization accelerator and mixing them.

[0091] Furthermore, the first step is performed by repeatedly kneading at 130°C for 10 minutes three times using a kneader. In the second step, materials other than the vulcanizing agent and vulcanization accelerator are added to the masterbatch prepared in the first step, and kneading is carried out at 130°C for 10 minutes using a kneader. The third step is performed by kneading at 40°C for 10 minutes using a mixing roller.

[0092] (Example 2) Except for replacing isoprene rubber with butadiene rubber, the rubber composition of Example 2 was prepared in the same manner as in Example 1.

[0093] (Example 3) Except for changing the number of mixing steps in the first process to twice, the rubber composition of Example 3 was prepared in the same manner as in Example 2.

[0094] (Example 4) Except for changing the number of mixing times in the first step to five, the rubber composition of Example 4 was prepared in the same manner as in Example 2.

[0095] (Comparative Example 1) Except for changing the number of mixing steps in the first process to once, the rubber composition of Comparative Example 1 was prepared in the same manner as in Example 2.

[0096] (Comparative Example 2) Except for changing the number of mixing times in the first step to eight, the rubber composition of Comparative Example 2 was prepared in the same manner as in Example 2.

[0097] [Test for determining the number of calcium carbonate aggregates] The rubber compositions obtained as described above are used to prepare vulcanized rubber test pieces (S1 type) as specified in JISK 6394:1976 "Test method for dynamic properties of vulcanized rubber" under vulcanization conditions of 150°C for 30 minutes.

[0098] [Measurement of the number of aggregates consisting of three or more calcium carbonate particles linked together] Smooth surfaces of rubber test pieces for both examples and comparative examples were prepared using a microtome (Leica, EM UC7). Scanning transmission electron microscope (STEM) images were taken at four locations using a JEM-2800 (Nippon Electron, Ltd.) at 150,000x magnification. The number of aggregates in a 1μm × 1μm square region within the obtained images was visually measured. The average number of aggregates measured at the four locations was calculated (rounded to the nearest decimal). The results are shown in Table 1.

[0099] (Image shooting conditions) Multiplier: 150,000x Thickness of the sample photographed: 80nm Accelerating voltage: 200kV Probe size: 1nm Image size (pixels): 512×512 Observation mode: STEM-DF (dark field image) Specifically, first, as described above, a scanning transmission electron microscope (STEM) image was obtained. Next, an elemental mapping image was obtained using an energy-dispersive X-ray spectrometer (JEM-2800 / SDD100GV, manufactured by NJEOL Ltd.) attached to the STEM, and Ca atoms from calcium carbonate were detected to determine the calcium carbonate within the microscope image. Then, the elemental mapping image was compared with a magnified image (a 1 μm × 1 μm square area) of the microscope image to visually measure the number of aggregates consisting of three or more calcium carbonate particles linked together. The results are shown in Table 1.

[0100] The following description will be given in more detail using Example 1 as an example. Figure 4 The image shown is a scanning transmission electron microscope image (150,000x magnification) of Example 1. Figure 5 This represents the element mapping image of Example 1. Figure 6 This represents a magnified view (1μm × 1μm square area) of a scanning transmission electron microscope image. Visual comparison is used to compare the images. Figure 5 Element mapping image and Figure 6 The number of aggregates in the scanning transmission electron microscope (STEM) image was measured by magnifying the image (a 1 μm × 1 μm square area). Furthermore, Figure 6 The circles indicate aggregates of three or more calcium carbonate particles linked together, and the dispersion morphology of aggregates containing seven or more calcium carbonate particles linked together is shown.

[0101] Furthermore, the aggregates in each embodiment are aggregates of 3 to 12 calcium carbonate particles linked together.

[0102] Furthermore, when measuring the number of aggregates, as described above, it is preferable to select at least four regions from any 1μm×1μm square image area, observe the dispersion morphology of calcium carbonate particles in each region, measure the number of aggregates, and calculate the average number of aggregates in the four regions.

[0103] [Attenuation Characteristics Test] Use such as Figure 2 The apparatus shown is used to evaluate the dynamic shear properties of a rubber composition. Specifically, a two-component rubber adhesive is applied to predetermined portions (the bonding portions of sample 21) of two sandblasted metal pieces 22 (140mm × 80mm, 9mm thick). The rubber composition of the example or comparative example is then sandwiched between the two metal pieces 22 and dried. It is then hot-pressed at 100°C for 10 minutes to produce a sample (70mm × 80mm, 5mm thick) 21. The apparatus is then vibrated in the direction of the arrow, based on… Figure 3The load-strain loop curves shown are used to evaluate the dynamic shear characteristics. That is, for the above-mentioned device, using an exciter (manufactured by Washimiya Seisakusho, DYNAMIC SERVO), an input signal oscillator (manufactured by Yokogawa Electric Corporation, Synthesized Function Generator FC320), and an output signal processor (manufactured by Ono Test Instruments Co., Ltd., Portable FFT Analyzer CF-3200), an excitation simulating a major earthquake was applied (shear distortion rate: 200% (relative to 200% of the sample thickness), frequency (f): 0.33 Hz, measurement temperature: 20 °C). From the analysis of the shear distortion value (δ) and load value (Qd) relative to the excitation time, the equivalent stiffness (Ke) and equivalent attenuation coefficient (Ce) were obtained according to the following equations (1) to (3), and the attenuation constant (he) was obtained from these values. In addition, in the following equations, ω=2πf, W=Keδ 2 / 2, ΔW represents the load-strain loop area (absorbed energy).

[0104] Equivalent stiffness: Ke (N / mm) = Qd / δ…(1) Equivalent attenuation coefficient: Ce (kN·s / m) = ΔW / πωδ 2 …(2) Attenuation constant: he=ΔW / 4πW…(3) The exponential conversion values ​​of the attenuation constants in each embodiment and the comparative examples were determined when the attenuation constant in Comparative Example 1 was set to 1.0 (baseline), and evaluated according to the following criteria. The results are shown in Table 1.

[0105] (Evaluation Criteria) ◎ (Excellent)... The decay constant (exponential conversion value) is above 1.3. 〇 (Good)... The decay constant (exponential conversion value) is greater than 1.0 and less than 1.3. The attenuation constant (exponential conversion value) of × (difference) is below 1.0.

[0106] As can be seen from the results in Table 1 above, the samples in the examples meet the requirements of the present invention, and therefore exhibit excellent attenuation characteristics. Specifically, it can be seen that the excellent attenuation characteristics are due to the fact that the number of aggregates formed by three or more calcium carbonate particles linked together is within a specific range of 5 to 15.

[0107] In contrast, as can be seen from the results in Table 1 above, the comparative sample does not meet the requirements of the present invention, and therefore its attenuation characteristics are insufficient.

[0108] Specifically, Comparative Example 1, which consisted of 25 aggregates of three or more calcium carbonate particles linked together, exhibited poor attenuation characteristics. Similarly, Comparative Example 2, which consisted of 1 aggregate of three or more calcium carbonate particles linked together, also showed poor attenuation characteristics.

[0109] As can be seen from the above, in the vibration-damping rubber laminate that is the requirement of the present invention, namely, the vibration-damping rubber laminate having a rubber layer formed by a vulcanizate of a rubber composition containing at least one of (A) isoprene rubber and butadiene rubber and (B) calcium carbonate, when the number of aggregates formed by three or more calcium carbonate particles connected together in any 1μm × 1μm square area in a scanning transmission electron microscope image obtained by photographing the rubber layer at a magnification of 150,000 times is in the range of 5 to 15, the attenuation characteristics are excellent.

[0110] The above embodiments illustrate specific aspects of the present invention, but these embodiments are merely examples and not intended to be limiting. Various modifications that will be apparent to those skilled in the art are within the scope of the present invention.

[0111] Industrial applicability The seismic isolation rubber laminate of the present invention can perform excellent functions as a seismic isolation rubber laminate used in large buildings such as high-rise buildings and bridges.

[0112] Explanation of reference numerals in the attached figures 10: Vibration isolation rubber laminate; 12: Rubber block; 14: Metal plate; 16: Rubber layer; 18: Upper mounting plate; 20: Lower mounting plate.

Claims

1. A seismic isolation rubber laminate, comprising a rubber layer formed from a vulcanizate of a rubber composition for a seismic isolation rubber laminate containing components (A) and (B) below, wherein, In a scanning transmission electron microscope image of the rubber layer obtained by taking a picture at 150,000x magnification, the number of aggregates consisting of three or more calcium carbonate particles connected together in any 1μm × 1μm square area ranges from 5 to 15. (A) At least one of isoprene rubber and butadiene rubber, (B) Calcium carbonate.

2. The vibration-damping rubber laminate according to claim 1, wherein, The number of aggregates formed by three or more calcium carbonate particles linked together is in the range of 6 to 10.

3. The vibration-damping rubber laminate according to claim 1 or 2, wherein, The content of component (B) is 25 to 80 parts by mass relative to 100 parts by mass of component (A).

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

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