Rubber composition and seismic isolator

Abstract

To provide a rubber composition that can maintain horizontal flexibility while withstanding high loads.SOLUTION: A rubber composition contains a rubber material and a filler dispersed in the rubber material. The filler has biaxial orientation properties.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a rubber composition and a seismic isolation device. [Background technology]

[0002] In recent years, research has been conducted into seismic isolation devices that suppress the transmission of vibrations during earthquakes to buildings. Such seismic isolation devices use rubber components that efficiently absorb energy (for example, see Patent Document 1).

[0003] Patent Document 1 describes a rubber composition having a rubber component and a filler. The filler is a flat-shaped organically modified filler, and adding the filler to the rubber component gives the rubber composition an appropriate anisotropy in the elastic modulus. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2004-263128 A Summary of the Invention [Problem to be solved by the invention]

[0005] Here, since a seismic isolation device using the rubber composition is used while being subjected to a load in the vertical direction, it is necessary to maintain flexibility in the horizontal direction while enduring a high load. However, the rubber composition described in Patent Document 1 has room for improvement in terms of compressive stress and elastic modulus due to shear in the horizontal direction.

[0006] Therefore, an object of the present invention is to provide a rubber composition and a seismic isolation device that can maintain flexibility in the horizontal direction while withstanding a high load. [Means for solving the problem]

[0007] In order to solve the above problem, according to one aspect of the present invention, Rubber material, A filler dispersed in the rubber material, There is provided a rubber composition characterized in that the filler has biaxial orientation.

[0008] In order to solve the above problems, according to another aspect of the present invention, A plurality of rubber plates formed into plates from the rubber composition of the present invention; A plurality of hard plates laminated between the plurality of rubber plates; a pair of support plates that sandwich and support the stacked rubber plates and the stacked hard plates in a stacking direction of the rubber plates and the hard plates; A seismic isolation device is provided, comprising: Effect of the Invention

[0009] The rubber composition of the present invention can withstand a high load while maintaining flexibility in the horizontal direction. [Brief description of the drawings]

[0010] [Figure 1] 1A and 1B are diagrams showing the configuration of a seismic isolation device. [Diagram 2] FIG. 2 is a partially enlarged cross-sectional view of the seismic isolation device. [Diagram 3] FIG. 3 is a graph showing the relationship between shear stress and compressive stress. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, a rubber composition and a seismic isolation device according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. The rubber composition and the seismic isolation device according to the present invention are not limited to the embodiment shown below.

[0012] (Configuration of seismic isolation device) Fig. 1A is a plan view of the seismic isolation device 10, and Fig. 1B is a cross-sectional view taken along line AA shown in Fig. 1A. Fig. 2 is a partially enlarged cross-sectional view of the seismic isolation device 10. Note that all of the attached drawings are schematic diagrams and do not show actual dimensions.

[0013] 1A, 1B and 2, the seismic isolation device 10 has a plurality of rubber plates 20, a plurality of hard plates 30, and a pair of support plates 40 (connecting plates). In addition to the above configuration, the seismic isolation device 10 of this embodiment has a pair of flange plates 50 and a protective rubber layer 60. In this embodiment, the plurality of rubber plates 20 and the plurality of hard plates 30 form a laminate 70.

[0014] The rubber plate 20 is made of a rubber composition. The rubber composition includes a rubber material and a filler.

[0015] As the rubber material, natural rubber (NR) is used. Examples of natural rubber include various grades such as SMR-CV60, STR-CV60, SVR-CV60, RSS#1, and RSS#3. In addition, various synthetic rubbers other than natural rubber can be used in combination with natural rubber as long as they do not impair the effects of the present invention. Examples of synthetic rubbers include diene rubbers such as isoprene rubber (IR), butadiene rubber (BR), styrene butadiene rubber (SBR), and butyl rubber (IIR), and olefin rubbers such as ethylene propylene rubber (EPM). Of the synthetic rubbers, diene rubbers are preferred from the viewpoint of durability.

[0016] The content of natural rubber in the rubber material is preferably 50% by mass or more, more preferably 75% by mass or more, and particularly preferably 90% by mass or more, of the entire rubber component.

[0017] Fillers are generally classified according to their particle shape, and this classification model is shown in Table 1.

[0018] [Table 1]

[0019] The filler according to the present embodiment has a biaxial orientation and is in the form of a plate or flake. Examples of plate-like or flaky fillers include kaolinite, basic magnesium carbonate, sericite, talc, mica, and the like.

[0020] The amount of the filler is not particularly limited, but is preferably within the range of 40 to 100 PHR (Per Hundred Rubber), and more preferably within the range of 60 to 100 PHR.

[0021] The hard plate 30 is disposed between the multiple rubber plates 20. The type of the hard plate 30 is not particularly limited as long as it is a steel plate. Examples of the hard plate 30 include a zinc-plated steel plate, a tin-plated steel plate (tinplate), and a tin-free steel plate that has been subjected to a chromate treatment. From the viewpoints of vertical load and horizontal deformation, the thickness of the hard plate 30 is preferably 1.0 mm or more.

[0022] The support plate 40 sandwiches the laminate 70 from the stacking direction of the multiple rubber plates 20 and the multiple hard plates 30. The support plate 40 has multiple first through holes 41 arranged therein for fixing the flange plate 50. The number of the multiple first through holes 41 is not particularly limited and is set appropriately. The support plate 40 is not particularly limited as long as it is a steel plate, and the same material as the hard plate 30 can be used. The thickness of the support plate 40 is preferably thicker than that of the hard plate 30. The thickness of the support plate 40 is preferably 6.0 mm or more from the viewpoints of durability against vertical loads and tolerance of horizontal deformation.

[0023] The flange plate 50 supports the support plate 40 from the stacking direction, and is disposed between the support plate 40 and the building, and between the support plate 40 and the foundation of the building. The flange plate 50 is provided with a plurality of second through holes 51 for fixing to the support plate 40. The number of the second through holes 51 is the same as the number of the first through holes 41. The plurality of second through holes 51 are disposed at positions corresponding to the plurality of first through holes 41. The outer edge portion of the flange plate 50 is provided with a third through hole 52 for fixing to the building and the foundation of the building. The number of the third through holes 52 is not particularly limited. The number of the third through holes 52 can be set appropriately. The flange plate 50 is not particularly limited as long as it is a steel plate, and the same material as the hard plate 30 and the support plate 40 can be used. The thickness of the flange plate 50 is preferably thicker than the hard plate 30 used. The thickness of the flange plate 50 is preferably 10.0 mm or more from the viewpoints of durability against vertical loads and tolerance of horizontal deformation.

[0024] The protective rubber layer 60 improves the durability of the seismic isolation device 10 by preventing the rubber plate 20 and the hard plate 30 from contacting the external environment. The rubber material used for the protective rubber layer 60 may be appropriately selected in consideration of waterproofing, adhesion and conformability with the hard plate 30, etc. The rubber material may be natural rubber that can be used as a rubber plate, diene-based synthetic rubber, or a rubber composition in which resin or the like is added to these. Examples of diene-based synthetic rubber include synthetic rubber materials such as isoprene rubber (IR), chloroprene rubber (CR), styrene butadiene rubber (SBR), butadiene rubber (BR), acrylonitrile butadiene rubber (NBR), and ethylene-propylene-diene rubber (EPDM). From the viewpoint of weather resistance, chloroprene rubber (CR) and ethylene-propylene-diene rubber (EPDM) are preferable as the rubber material. EXAMPLES

[0025] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples in any way.

[0026] [Preparation of rubber composition] The rubber materials used were natural rubber SVR-CV60 and isoprene rubber LIR30 (Kuraray Co., Ltd.). The carbon black used was Seast SP (Tokai Carbon Co., Ltd.). Whiten SSB Red (Shiraishi Calcium Co., Ltd.) was used as a spherical filler. Translink Clay 37 (BASF) was used as a platelet or flake filler. Valnoc PM (Ouchi Shinko Chemical Industry Co., Ltd.) was used as a co-crosslinking agent. Noccela NS (Ouchi Shinko Chemical Industry Co., Ltd.) was used as the vulcanization accelerator.

[0027] The materials were mixed in the composition ratios shown in Table 2 and kneaded uniformly using a Banbury mixer to obtain each rubber composition.

[0028] The materials of the rubber composition are shown in Table 2.

[0029] [Table 2]

[0030] [evaluation] (horizontal shear stress) The horizontal shear stress was defined as the stress when a shear test piece (a rubber plate 25 mm long x 25 mm wide x 3 mm thick sandwiched between two steel plates 25 mm long x 85 mm wide x 3 mm thick) was strained. The shear rate was 20 mm / min.

[0031] (Vertical compressive stress) The compressive stress in the vertical direction was defined as the stress when a compression set test piece (a large test piece conforming to JIS K 6262) was compressed in the vertical direction. The compression speed was 10 mm / min.

[0032] [result] Fig. 3 is a graph showing the relationship between shear stress and compressive stress. The horizontal axis of Fig. 3 shows shear stress, and the vertical axis shows compressive stress. The black filled symbols in Fig. 3 show working examples, and the white symbols show comparative examples. The circle symbols show the results when the strain is 10%, the triangle symbols show the results when the strain is 20%, and the square symbols show the results when the strain is 25%.

[0033] As shown in Figure 3, it can be seen that plate-like or flaky fillers provide greater reinforcement against compressive stress than spherical fillers. It can also be seen that the greater the strain, the greater the effect of the filler on shear stress and compressive stress. In the region where the strain is 25% or more, it can be seen that the effect of plate-like or flaky fillers can be significantly achieved by including 40 PHR or more of filler. It can also be seen that when the strain is 25%, plate-like or flaky fillers have a higher compressive stress than spherical fillers.

[0034] (effect) As described above, in the rubber composition of the present embodiment, the filler has biaxial orientation, and therefore the rubber composition can withstand a high load while maintaining flexibility in the horizontal direction. [Industrial Applicability]

[0035] The rubber composition of the present invention can withstand a high load while maintaining flexibility in the horizontal direction, and therefore can be effectively used in seismic isolation devices disposed in the seismic isolation layer between a building and its foundation. [Explanation of symbols]

[0036] 10 Seismic isolation device 20 Rubber Sheet 30 Hard plate 40 Support plate 41 First through hole 50 Flange plate 51 Second through hole 52 Third Through Hole 60 Protective rubber layer 70 Laminate

Claims

1. Rubber material, A filler dispersed in the rubber material, The rubber composition is characterized in that the filler has biaxial orientation.

2. The rubber composition according to claim 1, The rubber composition is characterized in that the filler has a plate or flake shape.

3. The rubber composition according to claim 2, The rubber composition has a filler content within a range of 40 to 100 PHR.

4. A plurality of rubber plates formed into a plate shape from the rubber composition according to any one of claims 1 to 3; A plurality of hard plates laminated between the plurality of rubber plates; a pair of support plates that sandwich and support the stacked rubber plates and the stacked hard plates in a stacking direction of the rubber plates and the hard plates; A seismic isolation device having the structure.

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