JP2005282723A - Base isolation bearing structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated rubber type base isolation bearing structure having high damping performance and superior weather resistance by integrally adhering a coating rubber layer having superior adhesiveness and ozone resistance onto a laminated part having a nominal shearing modulus level of G2.5 for coping with the high damping performance which is strongly required recently. <P>SOLUTION: The structure comprises the laminated part having internal rubber layers and rigid plates alternately laminated and a coating layer integrally adhered thereto to cover the outer periphery of the laminated part. The internal rubber layer 6 and the coating rubber layer 10 each use a natural rubber (a diene rubber) as a base rubber. The coating rubber layer 10 is formed of a rubber composition containing 1.5-7 pts.wt p-FDA and 0.5-4 pts.wt oil wax in terms of the 100 pts.wt natural rubber. The internal rubber layer 6 is formed of a rubber composition containing 0-2 pts.wt p-FDA in terms of the 100 pts.wt natural rubber. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a seismic isolation bearing structure that is provided between an upper structure such as a building and a foundation and suppresses shaking of the upper structure with respect to an earthquake.

  As this type of seismic isolation structure, a metal plate or other rigid plate and a soft layer having viscoelasticity such as rubber or the like are alternately stacked above and below the upper structure and the foundation. It is often used in seismic isolation devices with a lower flange.

  After installation, these seismic isolation devices are exposed to the outside air in a state in which they are always subjected to the load of the superstructure (the outer peripheral portion is inflated and pulled). For this reason, there exists a problem that it receives the effect | action of humidity, ozone, etc., and it is easy to produce local destruction, such as a crack. For this reason, many attempts have been made to improve the weather resistance of portions exposed to the outside air.

  A technique is disclosed in which a covering rubber layer provided on the outer periphery of a laminated portion is formed of butyl rubber (referred to as IIR), polyurethane rubber, ethylene propylene rubber (EPDM, etc.), ethylene vinyl acetate rubber having excellent weather resistance (for example, Patent Document 1). reference). However, this disclosed technique has a problem that the adhesion between the outer peripheral surface of the laminated portion and the covering rubber becomes insufficient, and the seismic isolation performance tends to deteriorate.

  In addition, the soft layer (inner rubber layer) of the laminated portion is added to 100 parts of natural rubber and / or gen-based synthetic rubber, 1.5 to 5 parts of p-phenylenediamine-based antioxidant and a petroleum system having a melting point of 45 to 75 ° C. A technique is disclosed in which the amount of the wax is more than 2 parts by weight, and the rubber composition is formed of anti-aging agent ≦ petroleum wax and 3.7 parts ≦ (anti-aging agent + petroleum wax) ≦ 12 parts ( For example, see Patent Document 2). This technology is an attempt to improve the weather resistance with natural rubber-based rubber, but the amount of petroleum-based wax is larger than 2 parts by weight and more than the amount of anti-aging agent. There is a problem that the adhesive force between the internal rubber layer and the rigid layer (iron plate) cannot be sufficiently obtained due to excessive increase. In particular, it is remarkable when vulcanizing at low temperature for a long time (at 105 ° C. for 9 hours), and a good seismic isolation effect cannot be obtained due to insufficient adhesion.

In addition, the applicant of the present invention has the above-mentioned seismic isolation bearing structure, a rubber soft layer, 100 parts of a Gen base rubber, 1.5 to 7 parts of a p-phenylenediamine antioxidant and 0.5 to 7 petroleum wax. It is proposed that the rubber composition is blended so as to satisfy the relationship of 3 parts ≦ anti-aging agent ≧ wax and 3 parts ≦ (anti-aging agent + petroleum wax) <10 parts (for example, patent document) 3). However, this proposal also has a problem that, as described above, the adhesive strength between the inner rubber layer and the rigid layer is insufficient and a good seismic isolation effect may not be obtained.
Japanese Patent Laid-Open No. 7-29394, claim 1 JP-A-11-303019, claim 1 JP 2002-89079 A, Claim 1

  The present invention further promotes the above proposal, and while ensuring that the outer periphery of the laminated portion is deteriorated by ozone and local destruction, the vulcanized adhesive force between the internal rubber layer and the rigid layer is ensured, and is good for a long period of time. The purpose is to provide a seismic isolation effect.

The seismic isolation bearing structure according to claim 1 is a seismic isolation bearing structure in which a laminated portion in which internal rubber layers and rigid plates are alternately laminated and a covering rubber layer covering the outer periphery of the laminated portion are bonded and integrated. Body,
The inner rubber layer and the covering rubber layer are both rubber compositions having a gen-based rubber as a base rubber, and the inner rubber layer is 0 to 2 parts by weight of p-phenylenediamine based on 100 parts by weight of the base rubber. A rubber composition containing an anti-aging agent, wherein the coating rubber layer comprises 1.5 to 7 parts by weight of a p-phenylenediamine-based anti-aging agent and 0.5 to 4 parts by weight with respect to 100 parts by weight of a base rubber. It is characterized by being a rubber composition containing the following petroleum wax.

  The present invention divides an internal rubber layer that performs a seismic isolation support function and a coated rubber layer that requires weather resistance exposed to moisture, ozone, etc., and the internal rubber layer is mainly composed of gen-based rubber and is an anti-aging agent. Uses a small amount of p-phenylenediamine-based anti-aging agent (referred to as p-FDA) to improve adhesion to rigid boards, and the coated rubber layer is a Gen-based rubber that emphasizes weather resistance and adhesion to internal rubber. The main component was p-FDA and petroleum wax. Examples of the gen-based rubber include natural rubber, isoprene rubber, styrene / butadiene rubber, butadiene rubber, butyl rubber, halogenated butyl rubber and the like.

  The covering rubber layer contains 1.5 to 7 parts by weight of p-FDA and 0.5 to 4 parts by weight of petroleum wax. When these contents are less than the lower limit, there is a tendency to be inferior in ozone resistance (weather resistance), and as the upper limit is exceeded, the adhesion to the internal rubber layer tends to be deteriorated, so the above range is set. The inner rubber layer contains 0 to 2 parts by weight of p-FDA. If it exceeds 2 parts by weight, the adhesion to the rigid plate becomes insufficient, and it is difficult to obtain seismic isolation performance.

  As p-FDA, N-isopropyl-N′-phenyl-p-phenylenediamine is used, and N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine, N , N′-diphenyl-p-phenylenediamine, N, N′-di-2-naphthyl-p-phenylenediamine, N-phenyl-N ′-(3-methacryloyloxy-2-hydroxypropyl) -p-phenylene Diamine, N, N′-bis (1-methylheptyl) -p-phenylenediamine, N, N′-bis (1,4-dimethylpentyl) -p-phenylenediamine, N, N′-bis (1-methyl) -3-ethylpentyl) -p-phenylenediamine, mixed diallyl-p-phenylenediamine, phenyl hexyl-p-phenylenediamine, phenyl o Chill -p- phenylenediamine are used in combination. In particular, N-isopropyl-N′-phenyl-p-phenylenediamine and N- (1,3-dimethylbutyl) -N′-phenyl- are good in that they are well dispersed in gen-based rubber and have an excellent anti-aging effect. The combined use with p-phenylenediamine is desirable.

  The petroleum wax may be composed only of normal paraffin, or may be one in which isoparaffin or the like is mixed in normal paraffin. Further, normal paraffin and microcrystalline wax may be used in combination. In addition, as for this petroleum-type wax, what has a melting | fusing point is the range of 45-75 degreeC oozes out on the surface, and it is easy to form a membrane | film | coat.

  The seismic isolation bearing structure according to claim 2, wherein the covering rubber layer has a total content of 3.0 to 100 parts by weight of the base rubber and the p-phenylenediamine-based antioxidant and petroleum wax. It is characterized by being 10 parts by weight and having a petroleum wax content equal to or less than the content of the anti-aging agent.

  In the coated rubber layer, p-FDA and petroleum wax are essential components for improving ozone resistance. However, if the total content is less than 3.0 parts by weight, local cracks due to ozone or the like are likely to occur. If it exceeds 10 parts by weight, a wax layer is formed on the surface of the unvulcanized rubber, which adversely affects the adhesion with the internal rubber layer, and therefore is in the above range.

  In addition to the p-FDA and petroleum wax, the inner rubber layer and the coated rubber layer include a reinforcing filler such as carbon black, a softening agent, a vulcanization accelerator, and a vulcanization such as stearic acid and zinc white. Includes rubber compounding agents such as accelerators and vulcanizing agents.

  The above-mentioned seismic isolation bearing structure preferably has a shear elastic modulus of the inner rubber layer of 0.2 to 0.6 MPa, ensures a shear elastic modulus in this range, and is made of the same type of base rubber. Since the coating rubber layer is provided, the shear elastic modulus, which is an index of damping property, has a damping property of G6 (0.58 MPa) as a nominal name from a high damping of G2.5 (0.24 MPa) as a seismic isolation bearing structure. And what was excellent in the weather resistance can be obtained.

  As is clear from the above description, in the seismic isolation bearing structure according to claim 1, since both the inner rubber layer and the covering rubber layer are made of gen rubber, the adhesiveness between them is good, and It can be made to have excellent seismic isolation. In addition, more p-FDA and petroleum wax are blended into the rubber layer exposed to moisture and ozone to suppress degradation due to ozone resistance and moisture, and the internal rubber layer is added with p-FDA. A small amount improves the adhesion to the rigid plate. In the seismic isolation bearing structure according to claim 2, the total amount of p-FDA and petroleum wax in the covering rubber layer according to claim 1, and the relationship between the amount of petroleum wax and the amount of p-FDA are defined, A good balance between adhesion and ozone resistance. By taking the said structure, the shear elasticity of a seismic isolation bearing structure can also be expanded from a name: G2.5 (0.2 MPa) to a name: G6 (0.6 MPa).

The seismic isolation bearing structure of the present invention is formed by bonding and integrating a laminated portion in which internal rubber layers and rigid plates are alternately laminated and a covering rubber layer covering the outer periphery of the laminated portion. Natural rubber (referred to as NR), which is a gen-based rubber, is used as a base rubber for both the rubber layer and the coated rubber layer, and the coated rubber part is composed of 4 parts by weight of p-FDA and 2.5 parts by weight with respect to 100 parts by weight of NR. A rubber composition containing a petroleum wax is used, and the inner rubber layer is composed of a rubber composition containing 1 part by weight of p-FDA and 0.5 parts by weight of a petroleum wax with respect to 100 parts by weight of NR. In addition to the above, 40 parts by weight of necessary rubber compounding agents such as HAF carbon, ZnO, and sulfur are blended in the rubber composition.
(Example)
Example 1 uses the base rubber composition shown in the column of base rubber type “NR” in Table 3, adds p-FDA and petroleum wax shown in Table 1, and kneads them using a normal rubber kneader. The obtained unvulcanized rubber compositions for the internal rubber layer and the coated rubber layer were each sheeted to a thickness of 2.5 mm, and then the following three test samples were prepared and evaluated. . The results are shown in the evaluation column of Table 1. Here, N-isopropyl-N′-phenyl-p-phenylenediamine was used as p-FDA, and normal paraffin having a melting point of 51.7 ° C. was used as petroleum wax.

1) Ozone resistance test Specified in JIS K6251 from a vulcanized coated rubber sheet in which an unvulcanized coated rubber sheet (thickness: 2.5 mm) is pressurized and heated at a temperature of 105 ° C. for 540 minutes. No. 1 dumbbells, 50% extended, put in a bath with an ozone concentration of 100 ppm and a temperature of 40 ° C., and after 96 hours, visually observe whether the test piece is cracked, The results are shown in the evaluation column of Table 1. A case where no crack is observed is indicated by ○, a particularly excellent one is indicated by ◎, and a case where a crack is recognized is indicated by ×.

2) Adhesion test between internal rubber and covering rubber An adhesion test and an adhesion test piece used therefor will be described with reference to a perspective view shown in FIG. Cut into 25 mm x 25 mm from unvulcanized internal rubber sheet 21 (thickness 2.5 mm) and unvulcanized coated rubber sheet (thickness 2.5 mm), thickness 3.2 mm, width 25 mm, long Adhering to the ends of 100 mm thick steel plates 22 and 22 ', the unvulcanized rubber sheets were stacked face to face, heated at 105 ° C for 540 minutes, vulcanized and bonded, and adhesion test A piece 20 was created.

  For evaluation of adhesion, the two steel plates 22 and 22 'are pulled and broken in the opposite directions of the arrows x and x', respectively, and the ratio of the area where the rubber is adhered is measured by visual observation and image processing of the fracture surface. did. What is broken at the interface between the inner rubber layer 21 and the coated rubber layer 21 ′ is rejected [×], and 90% or more of the whole is generated in the inner rubber layer 21 or the coated rubber layer 21 ′. The results are shown in the evaluation column of Table 1, where 100% of the internal rubber layer 21 or the covered rubber layer 21 ′ is [◎].

3) Adhesion test between internal rubber layer and rigid plate Except for using only an unvulcanized internal rubber sheet as the rubber sheet to be affixed to the iron plates 22, 22 ', the "2) Internal rubber and coating rubber An adhesion test piece was prepared in the same manner as in the “adhesion test”, a tensile fracture test was conducted in the same manner as in “2)” above, and any fracture occurring at the interface between the iron plate 22 and the internal rubber layer test piece 21 is rejected. [X], those in which 90% or more of the whole is broken inside the internal rubber layer 21 are judged as acceptable [◯], and the results are shown in the evaluation column of Table 1.

  In Examples 2 to 7, the compositions of the internal rubber and the covering rubber were changed as described in the composition column of Table 1, and the sample preparation method and the evaluation method were the same as in Example 1. The results are shown in the evaluation column of Table 1.

  In Comparative Examples 1 to 8, samples were prepared in the same manner as in Example 1 except that the amount of p-FDA, petroleum-based wax, or the type of base rubber was changed as shown in the composition column of Table 2. Tested and evaluated. The results are shown in the evaluation column of Table 2.

  The manufacturing procedure (see FIG. 1) of the seismic isolation bearing structure using the rubber composition of Example 1 described above is performed on the upper surface of the lower flange 1 (material = SS400, thickness = 36 mm, outer diameter = 1300 mm). An unvulcanized inner rubber layer 6 (thickness = 5.7 mm, outer diameter = about 800 mm) having the inner rubber composition of Example 1 mainly composed of rubber, and an adhesion treatment (sandblasting, followed by epoxy liquid adhesion) Rigid plates (steel plates) 7 (material = SS400, thickness = 4.3 mm, outer diameter = 800 mm) alternately laminated (rubber layer 6 = 28 layers, rigid plate 7 = 27 sheets, FIG. In FIG. 1, one part was omitted) and a laminated part was formed. An unvulcanized rubber sheet 10 having the coated rubber composition of Example 1 was wound around the outer peripheral surface to form an unvulcanized coated rubber layer 10. A split mold for vulcanization (not shown) is arranged along the outer peripheral surface of the covering rubber layer, and an upper flange 1 (material, thickness, outer diameter is the same as that of the lower flange) is attached to the upper surface, and the mold is formed in a cylindrical shape. After assembling, insert into a vulcanizing press, preheat at temperature = 70 ° C. for 10 hours, heat vulcanize at 140 ° C. for 16 hours, disassemble the mold and take out the vulcanized seismic isolation structure . In addition, at the time of heat vulcanization, a rod-shaped member having a good heat transfer coefficient is inserted into the through hole 9 so that the inside of the laminated portion can be easily heated.

It is sectional drawing of the seismic isolation bearing structure which concerns on this invention. It is a perspective view of the adhesion test piece which measures the adhesive force of the internal rubber layer and covering rubber layer which concern on this invention.

Explanation of symbols

1: Upper flange 2: Lower flange 5: Laminated portion 6: Internal rubber layer 7: Rigid plate 9: Through hole 10: Covered rubber layer 20: Adhesive test piece 21: Internal rubber layer 21 ′: Covered rubber layer 22, 22 ′ : Iron plate

Claims (2)

A base-isolated bearing structure formed by bonding and integrating a laminated portion in which an internal rubber layer and a rigid plate are alternately laminated and a covering rubber layer covering the outer periphery of the laminated portion,
The inner rubber layer and the covering rubber layer are both rubber compositions having a gen-based rubber as a base rubber, and the inner rubber layer is 0 to 2 parts by weight of p-phenylenediamine based on 100 parts by weight of the base rubber. A rubber composition containing an anti-aging agent, wherein the coating rubber layer comprises 1.5 to 7 parts by weight of a p-phenylenediamine-based anti-aging agent and 0.5 to 4 parts by weight with respect to 100 parts by weight of a base rubber. A seismic isolation bearing structure characterized in that it is a rubber composition containing a petroleum wax.   The coating rubber layer has a total content of 3.0 to 10 parts by weight of the p-phenylenediamine-based antioxidant and petroleum wax with respect to 100 parts by weight of the base rubber, and the petroleum wax content is the aging. The seismic isolation bearing structure according to claim 1, wherein the seismic isolation bearing structure is equal to or less than the content of the inhibitor.

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