JP2000035072A - Urethane elastomer composition for base isolation bearing body and base isolation bearing body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an urethane elastomer composition for a base isolation bearing body which has low initial rigidity and high strength and has a restitutive force even in a large distortion area, a base isolation bearing body which uses the urethane elastomer composition, has low shear modulus, endures high distortion, exhibits a base isolation mechanism during medium and small earthquakes, is suited for a detached house, and is manufactured in a short time compared with the conventional laminated rubber bearing body. SOLUTION: This urethane elastomer composition for a base isolation bearing body includes urethane elastomer and has 100% modulus 0.5 MPa or less, rupture extension 600% or more, and the rupture strength 8 MPa or more and this base isolation bearing body is formed by laminating the urethane elastomer composition for the base isolation bearing body with a steel plate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a urethane elastomer composition for a seismic isolation bearing, and a seismic isolation bearing using the urethane elastomer composition for a seismic isolation bearing as an elastomer layer. Specifically, a urethane elastomer composition for a seismic isolation bearing having a low initial rigidity, high breaking strength, high breaking elongation, and a restoring force in a large strain region,
A seismic isolation bearing in which an elastomer layer made of the urethane elastomer composition for the seismic isolation bearing and a steel plate are laminated,
Low seismic modulus (G), strong enough to withstand large strains, exerts good seismic isolation function not only for large earthquakes but also small and medium-sized earthquakes. .

[0002]

2. Description of the Related Art In recent years, seismic energy absorbing devices, that is, seismic isolation, seismic isolation, and seismic isolation devices have rapidly become widespread. As such a seismic isolation device, for example, a laminated rubber bearing body in which a rubber layer made of a rubber composition and a steel plate are alternately laminated is used. Such seismic isolation devices are very hard in the vertical direction and soft in the horizontal direction, that is, they have a low shear rigidity, and act to shift the natural vibration period of the structure from the vibration period of the earthquake. This is to make the acceleration received by the structure very small. Because the rubber composition used for the rubber layer of the conventional laminated rubber support has a high initial rigidity,
The laminated rubber bearing using such a rubber composition has a problem that vibrations from the ground are transmitted to the upper structure as it is when the earthquake has a small amplitude. That is, in the case of a small-to-medium-sized earthquake, the effect of seismic isolation cannot be obtained with a laminated rubber bearing using a conventional rubber composition. Therefore, as a means for realizing a low shear modulus (G) in order to obtain a seismic isolation effect even in a small or medium-sized earthquake, a method of adding a large amount of oil or the like to a rubber composition is performed. It is difficult to balance physical properties such as breaking strength and adhesion between the rubber composition and the steel sheet. In addition, the production of the laminated rubber support requires long-time vulcanization at a high temperature for vulcanization inside the rubber composition and adhesion between the rubber composition and the steel plate. Heretofore, various inventions have been proposed for obtaining a support having a low shear modulus (G). JP-A-4-27254
No. 0 proposes a laminated rubber bearing in which soft rubber (natural raw rubber) is covered with hard rubber (hardness 60) as a rubber layer, and this rubber layer and a steel plate are laminated.
However, in this laminated rubber support, the steel plate and the rubber layer are not adhered but are merely laminated, so that they cannot withstand actual use. Japanese Unexamined Patent Publication (Kokai) No. 61-228944 proposes a laminated rubber bearing body using rubber having different properties in the periphery and inside as a rubber layer. JP-A-1-116132,
JP-A-6-101740 discloses a peripheral constrained type in which a cylindrical hollow portion is formed at the center of a constrained body composed of a hard plate, a rubber-like elastic plate, and a viscoelastic member, and a viscous fluid is filled therein. Laminated rubber bearings have been proposed. However, in this laminated rubber support, although the diffusion of the viscous fluid inside is prevented by the restricting body, there is a problem that the reliability of the leakage of the viscous fluid or the like is lacking. Japanese Patent Application Laid-Open No. 3-244842 proposes a laminated rubber bearing body using two types of silicone rubber as a rubber layer. However, in this laminated rubber bearing, the outer surface of the laminated rubber bearing is covered with high-strength silicone rubber. However, there is a problem that the laminated rubber bearing may not be able to withstand the strain which should be able to withstand and break. For seismic isolation of light-weight objects such as detached houses, the initial strain (100% modulus) is set at 0.
There is a need for a bearing body having a low shear modulus region that cannot be satisfied with rubber even if a material having a low hardness of 5 MPa or less is used partially.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a urethane elastomer composition for a seismic isolation bearing having low initial stiffness, high strength, and a restoring force even in a large strain range. The seismic isolation bearing used has a low shear modulus, withstands high strains, exhibits seismic isolation function even for small and medium-sized earthquakes, and is suitable for detached houses, and can be manufactured in a shorter time than conventional laminated rubber bearings. To provide a bearing.

[0004]

That is, the present invention is directed to a seismic isolation bearing containing a urethane elastomer, having a 100% modulus of 0.5 MPa or less, a breaking elongation of 600% or more, and a breaking strength of 8 MPa or more. A urethane elastomer composition is provided.

The urethane elastomer comprises a urethane prepolymer having an NCO equivalent of 500 to 3000 and a polyfunctional high molecular weight polyol having a molecular weight of 1500 to 3000,
It is preferable that the urethane elastomer be reacted at an OH / NCO equivalent ratio in the range of 0.3 to 1.7.

It is preferable that the urethane elastomer composition further contains 0.5 to 20 parts by weight of a filler based on 100 parts by weight of the urethane elastomer.

Further, the present invention provides a seismic isolation bearing in which an elastomer layer and a steel plate are alternately laminated, wherein the elastomer layer is made of the urethane elastomer composition for the seismic isolation bearing. .

[0008] It is preferable that the seismic isolation bearing has a gap penetrating in the laminating direction of the elastomer layer and the steel sheet at a central portion of the elastomer layer and the steel sheet, and has a lead bar in the gap.

It is preferable that the seismic isolation bearing is formed by heating and bonding a primer-treated steel sheet and a urethane elastomer composition.

It is preferable that the seismic isolation bearing has an elastomer sheet having a hardness of 50 to 60 on a side surface in a laminating direction of the elastomer layer and the steel plate.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The urethane elastomer composition for a seismic isolation bearing of the present invention (hereinafter, referred to as the composition of the present invention) has a low initial rigidity,
Shows high strength, ie, 100% modulus is 0.1.
It is a composition having physical properties of 5 MPa or less, elongation at break of 600% or more, and strength at break of 8 MPa or more.
Here, the seismic isolation bearing is a laminate having a structure in which a plurality of elastomer layers made of an elastomer composition and steel plates are alternately laminated. If the initial stiffness is low, the object behaves as a soft object in the shear direction not only for a large amplitude swing but also for a small swing. Therefore, if such a composition of the present invention is used as an elastomer layer of a seismic isolation bearing, even for small and medium-sized earthquakes with small amplitude, the vibration from the ground is not transmitted to the structure above the bearing as it is, It can exhibit seismic isolation function. The 100% modulus of the composition of the present invention is 0.5 MPa or less and 0.1%.
It is preferably 2 MPa or less. Within this range, the shear elastic modulus (G) of the seismic isolation bearing using the composition of the present invention as an elastomer layer is low, and a sufficient seismic isolation effect is exhibited even when the amplitude is small. .

In the event of an earthquake, the seismic isolation bearings have a high strength, that is, have a high strength so that they are not distorted and destroyed by vibrations from the ground.
High breaking strength (breaking strength) and high breaking strain (breaking strain) are required. The composition of the present invention has a breaking elongation of at least 600% and a breaking strength of at least 8 MPa. Within this range, the composition of the present invention can exhibit a restoring force without being destroyed even in a large strain region assumed from earthquake motion. Breaking elongation is 650% or more, breaking strength is 9
It is preferably at least MPa. When the composition of the present invention is used as an elastomer layer of a base-isolated support, if the elongation at break is 600% or more as a urethane elastomer composition, the elongation at break when used as a base-isolated support is less than 450%. And can withstand high distortion. Accordingly, the composition of the present invention satisfies the above-mentioned specific ranges of 100% modulus, breaking strength, and breaking strain at the same time, so that the initial rigidity is low, the strength is high, and the strength to withstand high strain can be exhibited. .

[0013] The above-mentioned characteristics indicate that the NCO equivalent is 500 to 30.
A urethane prepolymer having a molecular weight of 1500 to 30
It can be obtained by a urethane elastomer composition containing a urethane elastomer as a main component obtained by reacting a polyfunctional high molecular weight polyol with a OH / NCO equivalent ratio of 0.3 to 1.7. The urethane prepolymer blended in the composition of the present invention has an NCO equivalent of 50.
0 to 3000, which is a reaction product obtained by reacting an excess of a polyisocyanate compound with a polyol compound. Examples of the polyisocyanate compound that produces such a urethane prepolymer include various isocyanate compounds used in ordinary polyurethane resin compositions. Specifically, 2,4-tolylene diisocyanate (2,4 -TDI), 2,6-tolylene diisocyanate (2,6-TDI), 4,4'-diphenylmethane diisocyanate (4,4'-MDI), 2,4 '
-Diphenylmethane diisocyanate (2,4'-MD
I), p-phenylene diisocyanate, polymethylene polyphenylene polyisocyanate, aromatic polyisocyanate such as xylylene diisocyanate (XDI), 1,5-naphthalenedi isocyanate (NDI); aliphatic polyisocyanate such as hexamethylene diisocyanate (HDI); Isophorone diisocyanate, H ₆ X
Alicyclic polyisocyanates such as DI (hydrogenated XDI) and H ₁₂ MDI (hydrogenated MDI); carbodiimide-modified polyisocyanates of the above polyisocyanates, and isocyanurate-modified polyisocyanates thereof; These may be used alone or in combination of two or more.

Examples of the polyol compound that forms the urethane prepolymer include polyether polyols, polyester polyols, other polyols, and mixed polyols thereof, as in the case of ordinary polyurethane resin compositions. Examples of polyether polyols include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, 4,4′-dihydroxyphenylpropane,
Dihydric alcohols such as 4'-dihydroxyphenylmethane; polyhydric alcohols such as glycerin, 1,1,1-trimethylolpropane, 1,2,5-hexanetriol and pentaerythritol; diamines such as ethylenediamine and aromatic diamine A saccharide such as sorbitol;
Polyoxytetramethylene oxide and the like obtained by adding one or more alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, and styrene oxide to the species or two or more species.

As the polyester polyol, one or two of ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, cyclohexanedimethanol, glycerin, 1,1,1-trimethylolpropane, and other low molecular polyols are used. Condensation polymer of at least one species with one or more of glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid, terephthalic acid, isophthalic acid, dimer acid, or other low molecular carboxylic acids or oligomeric acids Ring-opening polymers such as propionlactone and valerolactone.

Other polyols include those having a carbon-carbon bond in the main chain, such as acrylic polyols, polybutadiene polyols, hydrogenated polybutadiene polyols, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, and butane. Diol, pentanediol,
A low molecular polyol such as hexanediol is preferably exemplified. These polyols may be used alone or in combination of two or more.

When the urethane prepolymer is obtained from the above-mentioned polyol compound and polyisocyanate compound, the mixing ratio of the polyol compound and the polyisocyanate compound is usually from 0.6 to 0.6 polyisocyanate compound per equivalent (OH equivalent) of the polyol compound. 3 equivalents (NCO
Equivalent) is preferable, and 0.9 to 1.5 equivalent is more preferable. In addition, such a urethane prepolymer is obtained by mixing a polyol compound and a polyisocyanate compound in the above-described quantitative ratio, and mixing at 30 to 120 ° C, preferably 50 to 100 ° C.
It is manufactured by stirring with heating. The urethane prepolymer used in the synthesis of the composition of the present invention is NCO
The equivalent weight is 500-3000, preferably 1000-2000. Within this range, the initial rigidity (100% modulus) of the obtained composition of the present invention can be reduced, and the shear modulus can be reduced.

The polyfunctional high molecular weight polyol used for synthesizing the composition of the present invention has a molecular weight of 1500 to 3000.
And a polyol having two or more hydroxyl groups per molecule. As such a polyfunctional high molecular weight polyol, among the polyol compounds that can be used for the synthesis of the urethane prepolymer described above, the molecular weight is 1500 to
3000 can be exemplified. The molecular weight is 1
It is preferably from 800 to 2300. This polyfunctional high molecular weight polyol functions to bind the urethane prepolymer and extend the molecular chain, and since the resulting urethane elastomer has a long chain, a rigid urethane cross-linked and cured with an amine or a low molecular weight polyol. Unlike elastomers, they can be characterized by low initial stiffness (100% modulus).

The urethane elastomer contained in the composition of the present invention is obtained by mixing the urethane prepolymer and the polyfunctional high-molecular-weight polyol with one equivalent of the urethane prepolymer (NCO equivalent) in the range of 0.3 to 1.7.
Equivalent (OH equivalent), preferably 0.6 to 1.1 equivalent. Within this range, the initial rigidity (100% modulus) of the obtained urethane elastomer is 0.5 MPa or less, and a high breaking strength (breaking strength) of 600% or more due to the functional group in the molecule of the urethane elastomer.
, A high breaking strain (breaking strain) of 8 MPa or more can be obtained.

The composition of the present invention may further contain a filler in addition to the above essential components. By containing a filler, the breaking strength of the composition of the present invention obtained,
It is preferable because physical properties such as breaking strain are further improved. Furthermore, when the composition of the present invention is used as an elastomer layer of a seismic isolation bearing, by blending a filler, the composition of the present invention behaves as being harder in the vertical direction, and sufficiently supports the upper structure. Will be able to do it. Examples of the filler include calcium carbonate, magnesium carbonate, talc, mica, carbon black, silica and the like. The compounding amount of the filler is preferably 0.5 to 20 parts by weight, more preferably 5 to 15 parts by weight, based on 100 parts by weight of the urethane prepolymer.

The composition of the present invention may contain, in addition to the above components, other additives as long as the object of the present invention is not impaired. Other additives include plasticizers such as dioctyl phthalate, antioxidants such as phenol derivatives, aromatic amine derivatives and piperidine derivatives, and ultraviolet absorption such as 2-hydroxybenzophenones, benzotriazoles and salicylates. And organic pigments such as phthalocyanine and inorganic pigments.

The method for producing the composition of the present invention is not particularly limited. The urethane prepolymer and the polyfunctional high-molecular-weight polyol are mixed at the above-mentioned predetermined ratio, and if necessary, other additives are added. Then, it can be obtained by sufficiently kneading under reduced pressure and uniformly dispersing. A cured product of the composition of the present invention can be obtained by heating and curing at about 120 ° C. for about 20 minutes, similarly to a general polyurethane resin composition.

The seismic isolation bearing of the present invention is a seismic isolation bearing using the urethane elastomer composition for a seismic isolation bearing of the present invention as an elastomer layer of the seismic isolation bearing. Figures 1-3
An embodiment of the seismic isolation bearing of the present invention is shown in FIG. As the seismic isolation bearing, as shown in FIG. 1, an elastomer layer 2 made of the composition of the present invention and a plurality of steel sheets 4 made of, for example, a general structural steel sheet, a cold-rolled steel sheet, etc. were alternately laminated. The seismic isolation bearing 10 can be shown. As the seismic isolation bearing of the present invention, a flange-integrated seismic isolation bearing in which a flange is disposed on the upper and lower end surfaces of an elastomer layer and a steel plate and bonded to each other can be shown. When the seismic isolation support of the present invention has a flange, the seismic isolation support can be fixed to the upper structure of the seismic isolation support via the flange. Further, as shown in FIG. 2, a flange 6 is further provided on the upper and lower end surfaces of the laminate of the elastomer layer 2 and the steel plate 4.
a and 6b are arranged and bonded, and a lead-containing seismic isolation bearing 10 having a void in the center thereof along the laminating direction and in which a lead rod 8 is sealed can be shown. In such a lead-containing seismic isolation bearing, the lead rod 8 further improves the seismic isolation function. Furthermore, it is preferable to cover the side surface in the laminating direction of the elastomer layer and the steel sheet with an elastomer sheet. The elastomer sheet functions as a protective sheet for the elastomer layer and the steel plate, and the weather resistance of the seismic isolation bearing is improved. The elastomer sheet may be provided by being adhesively bonded to the side surface of the laminate in which the elastomer layer and the steel sheet are laminated, may be simply wound around the periphery of the laminate, or may be the upper and lower flanges 6a, 6b. Alternatively, the end of the sheet may be adhered or secured with bolts and nuts.

As the elastomer sheet that may cover the outer periphery of the seismic isolation bearing of the present invention, any one of a vulcanized rubber, a thermoplastic elastomer and a thermosetting elastomer may be used. And those having flexibility can be used. Examples of the unvulcanized rubber used as a raw material of the vulcanized rubber include natural rubber, isoprene rubber, styrene / butadiene copolymer rubber, natural rubber / styrene / butadiene copolymer rubber, natural rubber / butadiene rubber, and natural rubber. / Acrylonitrile butadiene rubber and the like are preferably exemplified. If necessary, add this unvulcanized rubber
Various additives such as a filler, a plasticizer, an antioxidant, a vulcanizing agent, a vulcanization accelerator, and a vulcanization aid can be blended. Examples of fillers include carbon blacks such as HAF carbon and SAF carbon, aroma oils and waxes as plasticizers, sulfur and zinc white as vulcanizing agents, and N-cyclohexyl- as vulcanization accelerators. 2-benzothiazolesulfenamide, dibenzothiazyl sulfide and the like,
Examples of the vulcanization aid include stearic acid and the like. Examples of the thermoplastic elastomer include ester-based, amide-based, urethane-based, styrene-based, olefin-based, and vinyl chloride-based elastomers, and elastomers in which rubber is dispersed therein. Among these, it is preferable to use an elastomer sheet having a JIS-A hardness of 50 to 60 as the elastomer sheet of the seismic isolation bearing of the present invention. Within this range, the seismic isolation bearing of the present invention can be protected from deterioration in weather resistance without breaking even when the seismic isolation bearing of the present invention is distorted.

As a method of manufacturing the seismic isolation bearing of the present invention,
A method is preferred in which after a primer treatment such as applying and baking a primer such as a phenol resin to a steel sheet in advance, the sheet is heated and bonded to the urethane elastomer composition. In this case, the urethane elastomer composition may be formed into a sheet in advance and cured by heating, and then the obtained sheet-shaped urethane elastomer composition may be heated and adhered to the steel sheet after the primer treatment, or Alternatively, the steel plate after the primer treatment may be fixed in a mold, and the uncured urethane elastomer composition may be poured into the mold and bonded by heating. The composition of the present invention does not require a long-time high-temperature heating vulcanization step for vulcanizing the inside of the rubber and bonding the rubber and the steel sheet as in the case of a conventional laminated rubber bearing, and can be cast and heated in a short time. It can be cured and the production time can be shortened. Examples of the primer include a phenol resin and a resol resin. As the heating temperature, the temperature of normal heat curing of the polyurethane resin, for example, 120 to 150 ° C., as the heating time,
About 5 to 30 minutes are preferable.

By adopting the above configuration, the urethane elastomer composition for a seismic isolation bearing of the present invention has a low initial rigidity (100% modulus) and a high breaking strength and breaking strain. The seismic isolation bearing of the present invention using such a composition of the present invention as an elastomer layer has a low shear modulus (G) and a sufficient restoring force in a large strain range. Since the shear modulus is low, even in the case of a ground motion having a small amplitude (a small-to-medium-sized earthquake), the seismic motion is exhibited without being transmitted to the structure above the base-isolated support. In addition, even if the structure above the seismic isolation bearing is a light-weight detached building such as a mortar wooden structure, the elastomer layer has a low shear modulus and high strength. Can show a seismic isolation effect. Further, the seismic isolation bearing of the present invention using the composition of the present invention containing a specific amount of filler as an elastomer layer behaves as being harder in the vertical direction, and more strongly supports the upper structure of the seismic isolation bearing. Can be done. The seismic isolation bearing of the present invention in which a lead bar is sealed in the center of the laminate of the elastomer layer and the steel plate has a better seismic isolation function. Since the composition of the present invention is a urethane elastomer composition, by heating and bonding to the steel sheet after the primer treatment, the urethane elastomer composition and the steel sheet can be bonded in a short time to form a laminate. Unlike the conventional laminated rubber composition, there is no need to heat and vulcanize at high temperature for a long time for internal vulcanization and heat bonding of rubber and steel plate. Can be shortened. Furthermore, the seismic isolation bearing of the present invention, in which the outer periphery of the laminate of the urethane elastomer composition and the steel sheet is covered with the elastomer sheet, is excellent in weather resistance. The production time including the attachment of the elastomer sheet can be performed in a short time only by coating the elastomer sheet on the laminate, and the productivity is high. Therefore, the seismic isolation support of the present invention can be suitably used as a seismic isolation support for a detached house, indoor furniture, home appliances, etc., for preventing various equipment from overturning.

[0027]

The present invention will be described more specifically with reference to the following examples. (Examples 1 and 2, Comparative Examples 1 to 4) Compounds were blended in the proportions shown in Table 1 to obtain urethane elastomer compositions. The compounds were compounded according to the compounding shown in Table 2 to obtain a rubber composition. Example 1
And 2, the urethane elastomer compositions obtained in Comparative Examples 1 to 3 were heated and cured at 120 ° C. for 20 minutes to obtain sheet-like cured products. The unvulcanized rubber obtained in Comparative Example 4 was 2M
The mixture was heated and vulcanized at 150 ° C. for 40 minutes under Pa pressure to obtain a vulcanized rubber sheet. JIS K using each sheet obtained
According to the method described in No. 6301, 100% modulus, breaking strength (breaking strength), and breaking strain (breaking strain) were measured. The results are shown in Table 1 below. FIG. 3 shows the relationship between the tensile strength and the elongation of each sheet. As shown in FIG. 3, the urethane elastomer compositions obtained in Examples 1 and 2 were as rigid as the urethane elastomer compositions obtained in Comparative Examples 1 and 2 and the rubber composition obtained in Comparative Example 4. Instead, the initial rigidity is sufficiently small. Also, when the urethane elastomer composition obtained in Comparative Example 3 is used for the elastomer layer of the seismic isolation bearing without exhibiting extremely large elongation with a small tensile strength as in the urethane elastomer composition, the upper structure can be sufficiently supported.

A seismic isolation bearing was prepared by using the compounds having the compositions shown in Examples 1 and 2 and Comparative Examples 1 to 4 by the following production method, and the shear modulus G and the fracture strain were measured by a fracture test. . Production of seismic isolation bearing 1) Elastomer bearing (Examples 1-2, Comparative Examples 1-3)
LJ200 (manufactured by Road Co., Ltd.) was applied, baked and primer-treated on a steel plate (130 × 130 × 1.0 mm ³ ).
The urethane prepolymer compositions obtained in Examples 1 and 2 and Comparative Examples 1 to 3 were poured into a mold in which four gaps each having a thickness of 3 mm can be formed at four places, and were cured by heating at 120 ° C. for 20 minutes. The mold was split to obtain a seismic isolation bearing. 2) Rubber Bearing (Compound Utilization of Comparative Example 4) The same primer-treated steel plate as used in the production of the elastomer bearing and an unvulcanized rubber having the composition of Comparative Example 4 were used.
After lamination with a sheet having a thickness of 1 mm, the mixture was heated and vulcanized at 150 ° C. for 40 minutes under a pressure of 2 MPa in a mold, and then the mold was divided to produce a bearing body. Evaluation method of support 1) Shear modulus G While applying a constant load to the support (0 to 250% strain), a horizontal vibration of 0.5 Hz is given to obtain a hysteresis curve, and a 100% modulus is obtained from this curve. Calculate the shear modulus. 2) Breaking strain A horizontal stress is applied to the above-mentioned support, and the strain [%] at the time of breaking is read. The results are shown in Table 1.

[0029] In the table, the unit of the compound is part by weight.

* 1: The composition of the rubber composition of Comparative Example 4 is shown below. Table 2 Compounding parts by weight Rubber (NR / BR = 70/30) 100 HAF grade carbon black 70 Resin high resin (QPA) 20 Aroma oil 10 Sulfur 1 Zinc oxide (zinc white) 5 Vulcanization accelerator (CBS) 2 Stearic acid 2

Each component in Table 1 is as follows. Urethane prepolymer A: ester type urethane prepolymer L-1350, manufactured by Takeda Pharmaceutical Co., Ltd. NCO equivalent = 1800 Urethane prepolymer B: ester type urethane prepolymer L-1660, manufactured by Takeda Pharmaceutical Co., Ltd. NCO equivalent = 1400 Polyfunctional high molecular weight polyol A: Polyester polyol ODX-106, manufactured by Dainippon Ink Industries, Ltd. Molecular weight = 2000 3,3′-dichloro-4,4′-diaminodiphenylmethane: MOCA, molecular weight = 267 manufactured by Ihara Chemical Co.

[0032]

Industrial Applicability The urethane elastomer composition for a seismic isolation bearing of the present invention has a low initial rigidity (100% modulus) which cannot be obtained with a conventional rubber composition, but also has a large breaking strength and breaking strain. The seismic isolation bearing of the present invention using such a urethane elastomer composition for a seismic isolation bearing of the present invention can achieve a low shear modulus that cannot be obtained with a conventional laminated rubber bearing, and has a large breaking strain. For this reason, it has the strength to withstand high strain. In addition, the seismic isolation bearing of the present invention can more firmly support the upper structure of the seismic isolation bearing by adding a filler to the urethane elastomer composition. The seismic isolation bearing of the present invention, whose outer periphery is covered with an elastomer sheet, has excellent weather resistance. The seismic isolation bearing of the present invention can be manufactured without requiring a long-time heating vulcanization step at a high temperature like the conventional laminated rubber bearing, and has high productivity.

[Brief description of the drawings]

FIG. 1 is a drawing showing an example in which a urethane elastomer composition for a seismic isolation bearing of the present invention is applied to a seismic isolation bearing of the present invention.

FIG. 2 is a drawing showing an example of a seismic isolation bearing of the present invention.

FIG. 3 shows urethane compositions obtained in Examples and Comparative Examples,
It is a graph which shows the relationship between tensile strength and elongation of a rubber composition.

[Explanation of symbols]

 2 Elastomer layer 4 Steel plate 6a, 6b Flange 8 Lead bar 10 Isolation bearing

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3J048 AA02 BA08 BA18 BB10 BD04 DA03 EA38 3J059 AB12 AB15 BA43 BC05 BC19 BD01 CB09 EA03 EA09 EA13 GA42

Claims (7)

[Claims] Claims: 1. An urethane elastomer containing 100%
A urethane elastomer composition for a seismic isolation bearing having a modulus of 0.5 MPa or less, a breaking elongation of 600% or more, and a breaking strength of 8 MPa or more. 2. The urethane elastomer comprises a urethane prepolymer having an NCO equivalent of 500 to 3000 and a polyfunctional high molecular weight polyol having a molecular weight of 1500 to 3000.
The urethane elastomer composition for a seismic isolation bearing according to claim 1, wherein the urethane elastomer is a urethane elastomer reacted in an OH / NCO equivalent ratio in the range of 0.3 to 1.7. 3. The urethane elastomer 100
The urethane elastomer composition for a seismic isolation bearing according to claim 1 or 2, wherein the filler is contained in an amount of 0.5 to 20 parts by weight based on parts by weight. 4. A seismic isolation bearing in which an elastomer layer and a steel plate are alternately laminated, wherein the elastomer layer comprises:
A seismic isolation bearing made of the urethane elastomer composition for a seismic isolation bearing according to any one of the above. 5. The seismic isolation bearing body has a gap in the center of the elastomer layer and the steel plate in the laminating direction of the elastomer layer and the steel sheet, and a lead bar is sealed in the gap. 4. The seismic isolation bearing according to 4. 6. The seismic isolation bearing according to claim 4, wherein the seismic isolation bearing is formed by heating and bonding a steel sheet treated with a primer and a urethane elastomer composition. 7. The seismic isolation bearing according to any one of claims 4 to 6, wherein the seismic isolation bearing has an elastomer sheet having a hardness of 50 to 60 covering a side surface of the elastomer layer and the steel plate in the laminating direction.