JP2000001576A - Rubber composition for base isolation laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a rubber compsn. which has horizontal stiffness with a low bearing pressure dependence and shear modulus not decreasing even under a high bearing pressure by specifying the ratio of modulus to static shear modu lus at a specified percentage deformation in a repeated deformation test with an autograph. SOLUTION: This compsn. exhibits an elasticity ratio of modulus M100 to static shear modulus Gs at the third time in a repeated 100% tensile deformation test with an autograph of 1.4 or higher and a ratio of modulus M300 at the third time in a repeated 300% tensile deformation test to M100 of 3.6 or lower. The compsn. is prepd. by compounding 100 pts.wt. rubber component comprising natural rubber alone or a mixture thereof with an isoprene rubber with up to 15 pts.wt. polymer (e.g. a chloroprene rubber) having a solubility parameter different from that of natural rubber by at least 0.3 (MPa)1/2, 1-30 pts.wt. clay mainly comprising hydrated aluminum silicate, a filler (e.g. carbon black), a vulcanizing agent (e.g. sulfur), a vulcanization aid, a vulcanization accelerator, an antioxidant, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber composition for a seismic isolation laminate, and more particularly, to a low rigidity in the horizontal direction (shear elastic modulus) with low surface pressure, and a decrease in shear elastic modulus even under a high surface pressure. The present invention relates to a rubber composition for a seismic isolation laminate which is suitable as a rubber layer of the seismic isolation laminate having a low content. Furthermore, the present invention relates to a rubber composition for a seismic isolation laminate having excellent linear rigidity in addition to the horizontal rigidity retaining performance.

[0002]

2. Description of the Related Art In recent years, vibration energy absorbing devices, especially seismic isolation devices, have been rapidly spreading. One form thereof is a seismic isolation laminate in which steel plates and rubber layers are alternately laminated.
The seismic isolation laminate is installed between the building and the foundation, mainly at the base of the pillar of the foundation, and changes the vibration cycle of the building that resonates with the ground motion such as an earthquake to a long cycle, reducing the ground motion entering the building Work to make it work. In order to prolong the vibration period (natural period) of the structures on the seismic isolation laminate at the time of the earthquake, recent seismic isolation laminates have been reduced in size by reducing the cross-sectional area of the seismic isolation laminate. The surface pressure tends to be higher. For example, in the case of a seismic isolation laminate used in a conventional building, the surface pressure was at most 100 kg / cm ² . The surface pressure can reach as high as 150 kg / cm ² . Furthermore, when an earthquake occurs, 150 kg / c suddenly
High surface pressure exceeding m ² may be applied. However, when the seismic isolation laminate is used under such a high surface pressure, the occurrence of rubber stress corresponding to horizontal deformation is reduced and the horizontal rigidity (shear modulus) of rubber is reduced. . As a result, the characteristics of the conventional seismic isolation laminate changed due to surface pressure, and stable performance could not be exhibited. Therefore,
Construction of a seismic isolation laminate that can maintain the same shear characteristics (horizontal rigidity) as under normal surface pressure even under a high load (high surface pressure) exceeding normal surface pressure of 150 kg / cm ² is desired.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vibration energy absorbing device which has low dependence of horizontal rigidity (shear elastic modulus) on surface pressure, does not decrease in shear elasticity even under high surface pressure. An object of the present invention is to provide a rubber composition suitable as a rubber layer of a seismic isolation laminate suitable as a seismic isolation device. It is a further object of the present invention to provide a rubber composition for a seismic isolation laminate having a large linear limit strain and a good linear performance in addition to a small dependence of horizontal rigidity on surface pressure.

[0004]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the problems in the prior art, and as a result, as a rubber composition for forming a rubber layer of a seismic isolation laminate, 100
% And modulus M _100, by using a rubber composition elasticity ratio represented by the ratio of the static shear modulus Gs is 1.4 or more, the surface pressure dependency of the horizontal stiffness of the seismic isolation laminate can be reduced Further, based on this finding, a compounding of a rubber composition capable of obtaining the characteristics of the seismic isolation laminate was found, and the present invention was completed.

[0005] That is, the present invention is based on the autograph 1
Third Modulus M in 00% Cyclic Deformation Tensile Test
An elastic ratio (M) expressed as a ratio of ₁₀₀ to the static shear modulus Gs
₁₀₀ / Gs) is 1.4 or more. The rubber composition is a natural rubber, and,
It is preferable that a polymer having a solubility parameter different from that of the natural rubber by 0.3 (MPa) ^1/2 or more is contained in an amount of 15 parts by weight or less based on 100 parts by weight of the natural rubber.

The rubber composition for a seismic isolation laminate according to the present invention has an elasticity ratio (M ₁₀₀ / Gs) of 1.4 or more and has a 100% repetitive deformation tensile test by an autograph. Modulus M at third elongation 300%
₃₀₀ and the stress ratio between the modulus M ₁₀₀ (M ₃₀₀ / M
₁₀₀ ) is desirably 3.6 or less. As described above, the seismic isolation laminate including the rubber composition having the elastic ratio of 1.4 or more and the stress ratio of 3.6 or less has a small horizontal pressure-dependent surface pressure and a linear limit strain. Large, good linear performance. As the rubber composition that satisfies the above elastic ratio of 1.4 or more and the stress ratio of 3.6 or less, when the rubber component amount in the composition is 100% by weight, isoprene rubber is 5 to 5%.
A rubber composition containing 100% by weight or a rubber composition containing clay in an amount of 1 to 30 parts by weight based on 100 parts by weight of the rubber component is exemplified.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
In the present specification, the modulus and the static shear modulus are values measured for the vulcanized rubber composition. The present invention
The ratio (M ₁₀₀ / Gs) of the third modulus (M ₁₀₀ ) of the rubber composition in the 100% cyclic deformation tensile test by an autograph to the static shear modulus (Gs). (Hereinafter referred to as "ratio") to a specific value or more, it is possible to reduce the surface pressure dependence of the horizontal rigidity (shear modulus) of the seismic isolation laminate using the rubber composition. The low surface pressure dependence of the horizontal stiffness of the rubber composition is obtained by specifying the rubber composition in a specific manner.

[0008] The surface pressure dependency of the seismic isolation laminate can be represented by the horizontal rigidity retention rate of the seismic isolation laminate. Here, the horizontal rigidity retention ratio is a ratio of the horizontal rigidity under a large surface pressure to a small surface pressure among two different surface pressures. For example, the fact that the shear modulus does not decrease even under a high surface pressure and the dependency on the surface pressure is small means that the horizontal rigidity retention ratio is large and a value closer to 1 is taken. In FIG.
FIG. 2 is a conceptual diagram showing an SS curve showing the relationship between the modulus and the shear strain when the modulus (tensile stress) and the shear strain of natural rubber are plotted on the vertical and horizontal axes, respectively. The fact that the horizontal rigidity retention rate of the seismic isolation laminate approaches 1 means that the rubber composition forming the rubber layer of the seismic isolation laminate deforms more linearly until it breaks due to tensile deformation. That's what it means. In FIG. 1, the SS curve indicating the relationship between the modulus and the shear strain is closer to a straight line, for example, closer to a curve indicated by a broken line.
Third modulus (M ₁₀₀ ) of various rubber compositions in a 100% repeated deformation tensile test by an autograph
And the elastic ratio (M _{100) represented} by the ratio of the static shear modulus Gs
/ Gs) and the horizontal rigidity retention of the seismic isolation laminate having the rubber composition as a rubber layer, the following results were obtained. The horizontal stiffness retention rate was a ratio of horizontal stiffness under a surface pressure of 300 kg to horizontal stiffness under a 150 kg pressure. From the results obtained, the elasticity ratio and the horizontal stiffness retention ratio are positively correlated, and the higher the elasticity ratio, the greater the horizontal stiffness retention ratio, that is, the smaller the surface pressure dependency, and the lower the ratio, the lower the horizontal stiffness retention ratio. It was found to be small, that is, the surface pressure dependency was large. In other words, it was found that the surface pressure dependency of the seismic isolation laminate was improved as the elastic ratio increased. Rubber generally has a tendency to decrease in elastic modulus when the deformation exceeds 50%, but that the elastic ratio increases
This means that this decrease is reduced, and to the extent of 100% deformation, which is an important deformation area in the actual seismic isolation laminate,
It can be said that the rubber composition deforms closer to a linear shape.
From this result, if the elastic ratio of the rubber composition is increased and the rubber composition is deformed more linearly in the deformation region of the actual laminate, the surface of the seismic isolation laminate using this rubber composition for the rubber layer can be obtained. It was found that the pressure dependency can be reduced. Conversely, if the modulus of the rubber composition at the time of 100% deformation is lower than Gs, the shear modulus under a high surface pressure is reduced, and the surface pressure dependence of the seismic isolation laminate using this rubber composition is reduced. The nature increases.

In particular, in a seismic isolation laminate having a rubber layer formed of a rubber composition having an elasticity ratio of 1.4 or more, the horizontal rigidity retention rate of the seismic isolation laminate using a conventional natural rubber-based rubber layer is reduced. The horizontal rigidity retention rate of the body (elasticity ratio 1.38 in the above table,
(Equivalent to a horizontal rigidity retention of 0.37), which is very preferable. However, if the elasticity ratio is less than 1.4, the horizontal rigidity retention is low, which is not preferable. Preferably, the elasticity ratio is 1.4-4.
0.

The rubber composition for a seismic isolation laminate of the present invention (hereinafter referred to as “the rubber composition”)
The rubber composition of the present invention) has an elasticity ratio of 1.4.
The rubber composition is not particularly limited as long as it is a rubber composition as described above, but it is preferable to use natural rubber as the rubber contained in such a rubber composition because of excellent balance of rubber properties after vulcanization. However, chloroprene rubber (CR), acrylonitrile-butadiene rubber (NBR), styrene / isoprene / styrene block copolymer (SIS), together with natural rubber, do not impair the object of the present invention.
Butyl rubber (IIR), halogenated butyl rubber (brominated, chlorinated, etc.), ethylene-propylene-diene rubber (EPDM), epoxidized natural rubber, trans-polyisoprene, norbornene ring-opening polymer (polynorbornene), styrene-butadiene rubber ( Rubber such as SBR), high styrene resin, and isoprene rubber can be suitably used. In addition to these natural rubbers, these rubbers may be used alone or in combination of two or more.

Further, the rubber composition has a solubility parameter (SP value) of 0.3 (MPa) which is equal to the SP value of natural rubber.
^It is more preferable to mix polymers that differ by ^1/2 or more. The compounding amount of the above polymer is natural rubber or a total of 1 rubber which can be used together with natural rubber.
15 parts by weight or less is preferable with respect to 00 parts by weight,
0 parts by weight is more preferred. Within this range, the elastic ratio becomes 1.4 or more without impairing other physical properties such as elongation of the obtained rubber composition.

As shown in FIG. 1, the rise of the SS curve at the time of low distortion of natural rubber is smaller than that at the time of high strain because at the time when the distortion is small, the natural rubber elongates around the bonding axis of the molecule. Is due to the entropy elasticity based on the change in the form of the molecule due to the rotational motion of the rubber molecule.
It is considered that the modulus does not increase as compared with the increase in the amount of strain, because it is not due to the energy elasticity in which the bond length of -C changes. If the strain applied to the rubber molecules increases, the rubber will be stretched completely, or the rubber molecules will be oriented, or elongation crystallization will occur, and the rotational motion of the rubber molecules will not occur. With an increase in the amount of, the modulus increases and the slope of the SS curve becomes steeper. The above-described polymer having an SP value having a large difference from the SP value of natural rubber has a relatively large substituent in the molecule and has a large polarity. When these polymers are blended with natural rubber,
Relatively large substituents in the polymer can suppress the rotational movement of the natural rubber molecule around the bonding axis at low strain,
It is considered that the entropy elasticity with respect to the elongation of the rubber composition and the contribution of energy elasticity due to a change in the bonding distance in the molecule can be increased, so that the elastic ratio of the rubber composition can be increased.

The present inventor has proposed that the elastic ratio (M ₁₀₀
/ Gs) is not less than 1.4 and a rubber composition having a stress ratio (M ₃₀₀ / M ₁₀₀ ) between the modulus M ₃₀₀ at 300% elongation and the modulus M ₁₀₀ is 3.6 or less. In addition to the characteristic that the horizontal rigidity is less dependent on the surface pressure and the horizontal rigidity retention performance is excellent, it has been found that the seismic laminate has good linear performance.

Here, that the seismic isolation rubber laminate has good linear performance means that the linear limit strain value of the rubber laminate is large.
It means that the hardening tendency of rubber is not extremely strong.
The linear limit strain of the rubber laminate is as shown in FIG.
Stress relationship line (SS curve) and slope Kh ₁ = 1.2
It is obtained as a distortion value (%) at the intersection with the straight line indicated by (Kh). Kh is the shear strain of the rubber laminate ± 100%
This is the third gradient when deformed three times with. The SS curve shown in FIG. 2 shows that the rubber laminate had a shear strain of ± 100% and 3
This is a strain-stress relationship line when a load is applied in one direction after being repeatedly deformed, and the straight line is ± 100% passing through a stress value = 0.
This is a straight line having a gradient obtained by multiplying the gradient Kh at the time of distortion by 1.2 times.

Hardening of rubber means that rubber molecules are oriented (or stretched and crystallized) by a load (strain) in one direction of rubber, and the rise of SS curve, that is, modulus (tensile stress). It appears as an increase. This is because, as described in FIG. 1, when the rubber molecules are oriented, the rubber elongates due to the energy elasticity due to the rotational movement of the rubber molecules, and the elastic energy amount with respect to the rubber elongation increases. At this time, the fact that the hardening tendency of the rubber is large means that the SS curve sharply rises (thick broken line in FIG. 2), but in the present invention, the rise of the SS curve is gradual and the hardening tendency is high. (Solid line in FIG. 2) is preferable because of its excellent linear performance.

The linear limit strain (%) of the seismic isolation rubber laminate as described above is specifically 220% or more, preferably 250%.
% Is desirable. In the present invention, it is possible to evaluate the linear performance of the seismic isolation rubber laminate by directly measuring the linear limit strain value, but it may be evaluated by the stress ratio of the rubber composition as described above.

That is, the present inventor studied the rubber composition used in the seismic isolation laminate, and found that the stress ratio (M M) between the modulus M ₃₀₀ of the rubber composition and the modulus M ₁₀₀ was
_It was found that when the ratio ( ₃₀₀ / M ₁₀₀ ) is 3.6 or less, hardening tendency does not extremely occur, and a seismic isolation laminate having a large linear limit distortion and good linear performance can be obtained. The finding that when the stress ratio of the rubber composition is 3.6 or less, the linear performance of the seismic isolation laminate is good (the linear limit strain is large) was found by the present inventors. Several examples are shown in the following table together with the relationship between the elastic ratio and the horizontal rigidity retention.
FIG. 3 further shows the relationship between the stress ratio and the linear limit strain.
Shown in The modulus M ₃₀₀ is the tensile stress at the time of the third 300% elongation (shear strain) in a 300% repeated deformation tensile test using an autograph.

[0018] In the table, the horizontal stiffness retention ratio ^* is the ratio of each horizontal stiffness under a surface pressure of 250 kg and 150 kg.

In the present invention, based on the above findings, the rubber composition preferably has an elastic ratio of 1.4 or more and a stress ratio of 3.6 or less. A seismic isolation laminate having good horizontal rigidity retention and good linear performance can be obtained. As described above, the elastic ratio of the rubber composition is 1.4 or more, preferably 1.4 to 4.0, and the stress ratio is 3.6 or less, preferably 3.3 to 3.5.
It is desirable that

Specifically, as the rubber composition satisfying such an elastic ratio and a stress ratio, when the rubber component amount in the rubber composition is 100% by weight, isoprene rubber among the rubbers exemplified above is used. 5 to 100% by weight, preferably 1 to 5
Rubber compositions containing 0% by weight. The isoprene rubber may be a general-purpose isoprene rubber, and is not particularly limited. For example, an isoprene rubber having a cis 1,4-bonded polyisoprene content of about 92% by weight or more may be manufactured using a lithium catalyst system or manufactured using a Ziegler catalyst system. . The rubber component other than the isoprene rubber may be any natural rubber.

As a rubber composition that satisfies the above elastic ratio and stress ratio, one clay is added to 100 parts by weight of the rubber component.
And 30 to 30 parts by weight, preferably 5 to 15 parts by weight. The clay may be a clay mainly composed of hydrated aluminum silicate, and may be a clay having a relatively large particle size, which is widely used as a soft clay. For example, kaolin clay, pyrophyllite clay, sericite clay and the like can be used. The rubber component of the rubber composition containing the clay is preferably a natural rubber among the rubbers exemplified above.

In the rubber composition of the present invention as described above, in addition to the above-mentioned components, a filler, a vulcanizing agent, a vulcanization aid, a vulcanization accelerator, an antiaging agent, as long as the object of the present invention is not impaired. Agents, plasticizers, processing aids, softeners, pigments and the like. Examples of the filler include carbon black, calcium carbonate, talc, hard clay, and soft clay. As the vulcanizing agent, sulfur, sulfur chloride, zinc white, TM
Organic sulfur-containing compounds such as TD; organic peroxides such as dicumyl peroxide; As the vulcanization accelerator, N
Sulfenamides such as -cyclohexyl-2-benzothiazolesulfenamide (CBS), thiazoles such as mercaptobenzothiazole, and thiuram such as tetramethylthiuram monosulfide. Examples of anti-aging agents include ketone / amine condensates such as TMDQ,
Examples include amines such as NPD and monophenols such as styrenated phenol. DBP,
Monoesters such as phthalic acid derivatives such as DOP and sebacic acid derivatives such as DBS. Examples of the softener include aroma oil and the like.

The method for producing the rubber composition of the present invention includes:
There is no particular limitation, and a conventionally known method, for example, each component other than the vulcanizing agent and the vulcanization accelerator is first kneaded with a Banbury mixer or the like, and then, a vulcanizing agent such as sulfur and a vulcanizing agent are mixed with a kneading roll machine or the like. A method of kneading the accelerator can be exemplified. The resulting rubber composition can be cured by heating to form a vulcanized rubber sheet. At this time, the amount of the vulcanizing agent, the degree of vulcanization according to the vulcanizing temperature and the heating time were adjusted so that the elastic ratio of the obtained rubber composition was 1.4 or more.
Adjust with the amount of polymer with a large difference in value.

The seismic isolation laminate in which the rubber composition of the present invention is used is a laminate in which rubber layers and hard plates are alternately laminated, and is a structure used for a bridge support, a building base seismic isolation, and the like. Body. An iron plate, a steel plate or the like is used for the hard plate, and the above-mentioned rubber composition is suitably used for the rubber layer. An example of a method for manufacturing such a seismic isolation laminate will be described. The steel sheet may be subjected to a surface treatment such as a mechanical treatment, a chemical treatment, or a mechanical treatment in advance, and the surface is degreased and an adhesive is applied. At this time, a primer may be applied. On the other hand, the rubber composition in an unvulcanized state is rolled to a predetermined thickness and punched into a predetermined shape to obtain a rubber sheet. After the adhesive applied to the steel sheet is dried, a rubber sheet is laminated, and then the steel sheet and the rubber sheet are integrally heated and vulcanized to obtain a seismic isolation laminate.

Since the rubber composition of the present invention has the above-mentioned constitution and has an elasticity ratio of 1.4 or more, it is necessary to increase the horizontal rigidity retention of a seismic isolation laminate using the rubber composition of the present invention for a rubber layer. Therefore, the dependency of the horizontal rigidity of the seismic isolation laminate on the surface pressure can be reduced. Further, the rubber composition of the present invention containing a specific amount of a polymer having a SP value in a specific range has an elasticity ratio of 1.4 or more, and has a horizontal rigidity of a seismic isolation laminate having a rubber layer made of the rubber composition. The surface pressure dependency can be reduced. Furthermore, when the stress ratio of the rubber composition is 3.6 or less, the seismic isolation laminate has excellent linear performance. Therefore, the rubber composition of the present invention can be suitably used as various types of vibration energy absorbing devices installed on the foundation of a building or the like, particularly as a rubber layer of a seismic isolation laminate. In addition, 150kgf /
It is preferably used as a rubber layer of a seismic isolation laminate used under a high surface pressure of ² cm ² or more.

[0026]

The present invention will be described below in more detail with reference to examples. (Examples 1 to 12) 25 parts by weight of carbon black (GPF), 3 parts by weight of zinc white, and 100 parts by weight of rubber and polymer in the rubber and polymer having the composition shown in Table 1 below.
2 parts by weight of stearic acid, an antioxidant (6C: N- (1,
3 dimethylbutyl) -N'-phenyl-P-phenylenediamine) 2 parts by weight and 15 parts by weight of aroma oil are blended and kneaded, 1.1 parts by weight of sulfur, vulcanization accelerator (CBS)
A rubber composition was prepared by mixing 1.2 parts by weight,
For 30 minutes to obtain a vulcanized rubber. Each of the obtained vulcanized rubbers was subjected to a tensile test, and the breaking strength T _B , the breaking elongation E _B , the static shear modulus Gs, and the modulus M ₁₀₀ were measured, and the elastic ratio was determined. Table 1 shows the results.

Comparative Example 1 Carbon black (GPF) 25 parts by weight, zinc white 3
Parts by weight, stearic acid 2 parts by weight, antioxidant (6C) 2
Parts by weight and 15 parts by weight of aroma oil were blended and kneaded, and 1.1 parts by weight of sulfur and 1.2 parts by weight of CBS were blended to prepare a rubber composition, and a vulcanized rubber was obtained in the same manner as in the Examples. . The obtained vulcanized rubber was subjected to a tensile test in the same manner as in the example, and the breaking strength T _B , the breaking elongation E _B , and the static shear modulus G were measured.
s, the modulus M ₁₀₀ was measured to determine the elasticity ratio. Table 1 shows the results.

Comparative Example 2 100 parts by weight of natural rubber, 5 parts by weight of carbon black (GPF), 3 parts by weight of zinc white, 2 parts by weight of stearic acid, 2 parts by weight of antioxidant (6C), and aroma oil 4 Parts by weight and kneaded, 1.6 parts by weight of sulfur and 1.0 part by weight of CBS were blended to prepare a rubber composition, and a vulcanized rubber was obtained in the same manner as in the Examples. The obtained vulcanized rubber was subjected to a tensile test in the same manner as in the example, and the breaking strength T _B , the breaking elongation E _B , and the static shear modulus G were measured.
s, the modulus M ₁₀₀ was measured to determine the elasticity ratio. Table 1 shows the results.

(1) Tensile test According to JIS K6251, breaking strength (T_B)
[Kgf / cm^Two], Elongation at break (E_B) Measure [%]
Was. (2) Static shear modulus (Gs) [kgf / cm^Two] It measured according to JISK6254. (3) Elasticity ratio (M₁₀₀/ Gs) Autograph in 100% repeated deformation tensile test
Third modulus M ₁₀₀[Kgf / cm^Two]
Was. This M₁₀₀Value and the static shear modulus measured above
(Gs) and the elasticity ratio (M₁₀₀/ Gs) ratio
Was.

[0030]

[Table 1]

<Solubility Parameter of Each Component in Table> Natural Rubber: Solubility Parameter SP = 17.0 (MPa)
^1/2 SBR: SP = 17.5 (MPa) ^1/2 CR: SP = 19.2 (MPa) ^1/2 NBR: SP = 20.2 (MPa) ^1/2 EPDM: SP = 16.4 (MPa) MPa) ^1/2

Examples 13 to 16 Vulcanized rubbers were obtained in the same manner as in Example 1 except that the amount of isoprene in the rubber component was changed to the amount shown in Table 2. A tensile test was performed on the obtained vulcanized rubber, and the breaking strength T _B , breaking elongation E _B , static shear modulus Gs, modulus M ₁₀₀ and modulus M _{300 were} measured.
Was measured, and the elastic ratio and the stress ratio were determined. Table 2 shows the results. (4) Modulus M ₃₀₀ at the time of the third 300% elongation in a 300% cyclic deformation tensile test using an autograph of modulus M ₃₀₀ [kgf /
cm ² ] was measured. (5) was determined and the value of the stress ratio (M ₃₀₀ / M ₁₀₀₎ the modulus M _300, stress ratio from the value of the modulus M ₁₀₀ a (M ₃₀₀ / M _100).

(Comparative Example 3) The procedure of Example 16 was repeated, except that natural rubber was used instead of isoprene rubber as the rubber component. Table 2 shows the results.

[0034]

[Table 2]

Examples 17 to 19 Vulcanized rubbers were obtained in the same manner as in Example 1 except that the rubber compositions shown in Table 3 were used. The obtained vulcanized rubber was subjected to a tensile test, and the breaking strength T _B , breaking elongation E _B , static shear modulus Gs, modulus M ₁₀₀ and modulus M ₃₀₀ were measured, and the elastic ratio and stress ratio were determined. Table 3 shows the results. The clay used was mainly composed of hydrous aluminum silicate.

(Comparative Example 4) The procedure of Example 17 was repeated, except that no clay was added.
Table 3 shows the results.

[0037]

[Table 3]

[0038]

The rubber composition of the present invention has a predetermined elasticity ratio, so that the horizontal rigidity of a seismic isolation laminate having the rubber composition of the present invention as a rubber layer can be made less dependent on surface pressure. it can. Furthermore, by setting the stress ratio of the rubber composition to a specific value, a seismic isolation laminate having good linear performance can be obtained.
Therefore, the rubber composition of the present invention is a vibration isolator, a vibration isolator,
It can be suitably used as a rubber composition for a seismic isolation laminate for the purpose of absorbing vibration energy of a seismic isolation device or the like.

[Brief description of the drawings]

FIG. 1 is a graph showing a correlation between modulus of natural rubber and shear strain.

FIG. 2 shows a strain-stress relationship line (SS curve) for obtaining a linear limit strain of the rubber laminate.

FIG. 3 shows a stress ratio-linear limit strain correlation diagram of the seismic isolation rubber laminate.

Claims (5)

[Claims] 1. 100% repeated deformation by autograph
Third Modulus M in Tensile Test ₁₀₀And the static shear bullet
Ratio to the Gs (M₁₀₀/ Gs) is 1.4 or more
Rubber composition for earthquake laminate. 2. The rubber composition according to claim 1, wherein the rubber composition has a solubility parameter of 0.3 to the solubility parameter of the natural rubber.
The (MPa) ^1/2 or more different polymers, wherein the natural rubber 1
2. The composition according to claim 1, wherein the content is 15 parts by weight or less based on 00 parts by weight.
The rubber composition for a seismic isolation laminate according to the above. 3. In addition to the ratio (M ₁₀₀ / Gs) being not less than 1.4, a modulus M ₃₀₀ at the time of a third elongation of 300% in a 300% cyclic deformation tensile test by an autograph; seismic isolation laminate-body rubber composition according to claim 1 ratio of the modulus _{M 100 (M 300 / M 100} ) is 3.6 or less. 4. The rubber component content in the rubber composition is 100% by weight.
The rubber composition for a seismic isolation laminate according to claim 3, wherein the rubber composition contains isoprene rubber in an amount of 5 to 100% by weight. 5. The rubber composition for a seismic isolation laminate according to claim 3, wherein the clay is contained in an amount of 1 to 30 parts by weight based on 100 parts by weight of the rubber component.