JP5574616B2 - Rubber composition for laminated rubber of seismic isolation structure - Google Patents

Description

  The present invention relates to a rubber composition for a laminated rubber having a base-isolated structure, and more particularly, a rubber composition for a laminated rubber having a base-isolated structure capable of sufficiently suppressing the Malins effect and having a small history dependence of elastic modulus. It is about.

  Conventionally, seismic isolation structures using laminated rubber in which soft plates with viscoelastic properties, such as rubber, and hard plates, such as steel plates, are laminated alternately, are used for structures such as basic seismic isolation of buildings, bridges and elevated roads. The seismic isolation structure is used to support structures, structures and structures and their structures when the vibrations due to earthquakes are applied to buildings and structures. It plays a role of minimizing damage to humans and equipment (see Patent Document 1 below).

  On the other hand, in general vulcanized rubber, the phenomenon that the elastic modulus decreases due to repeated deformation, the so-called Mullins effect occurs, the desired performance cannot be stably exhibited, and the product design using the rubber member May be complicated. In particular, in rubber members used for laminated rubber of seismic isolation structures, there is a great demand for the development of a rubber composition having a small Malin's effect because the elastic modulus after deformation caused by the Malin's effect is greatly reduced.

  On the other hand, for example, JP 2000-336207 A (Patent Document 2) includes a diene rubber, a resin, a softening agent, and a reinforcing agent as a highly damped rubber composition having a small history dependency. In addition, a rubber composition produced through two-stage kneading is disclosed, and JP-A 2007-126560 (Patent Document 3) discloses an aromatic oligomer to which ethylene oxide is added, and a rubber component. A rubber composition comprising

JP 2002-48190 A JP 2000-336207 A JP 2007-126560 A

  However, even with the laminated rubber using the rubber composition disclosed in Japanese Patent Application Laid-Open No. 2000-336207 and Japanese Patent Application Laid-Open No. 2007-126560, the Malins effect cannot be sufficiently suppressed, and the history of the elastic modulus still remains. There was room for improvement in dependency.

  Accordingly, an object of the present invention is to provide a rubber composition for laminated rubber having a base-isolated structure that solves the above-described problems of the prior art, can sufficiently suppress the Malins effect, and has a small history dependence of elastic modulus. There is to do.

  As a result of diligent studies to achieve the above object, the inventors of the present invention have a sufficient Malins effect of a laminated rubber using the rubber composition by composing a rubber composition by adding a fatty acid salt to the rubber component. As a result, the present invention has been completed.

That is, the laminated rubber The rubber composition for a seismic isolation structure of the present invention, with respect to 100 parts by mass of the rubber component, Ri name by blending fatty acid salt 0.1 parts by mass or more, the fatty acid salt is potassium oleate It is characterized by including .

  In a preferred example of the rubber composition for laminated rubber of the seismic isolation structure of the present invention, the amount of the fatty acid salt is 3 parts by mass or less with respect to 100 parts by mass of the rubber component. In this case, the processability of the rubber composition is good.

In the laminated rubber Rubber composition of the seismic isolation system of the present invention, the fatty acid salt, potassium oleate, zinc oleate, preferably contains potassium stearate and zinc stearate.

  ADVANTAGE OF THE INVENTION According to this invention, the rubber composition for laminated rubber of the seismic isolation structure which mix | blends a specific amount of fatty acid salt with respect to a rubber component, and can fully suppress a Malins effect can be provided.

It is sectional drawing of an example of the seismic isolation structure which provides the laminated rubber using the rubber composition of this invention. It is a perspective view of a test sample.

The present invention is described in detail below. Rubber The rubber composition for a seismic isolation structure of the present invention, with respect to 100 parts by mass of the rubber component, Ri name by blending fatty acid salt 0.1 part by mass or more, that the fatty acid salt comprises potassium oleate It is characterized by. By using the rubber composition of the present invention in which the fatty acid salt is blended for the laminated rubber of the seismic isolation structure, the Malins effect of the laminated rubber can be sufficiently suppressed. Therefore, the seismic isolation structure including the laminated rubber using the rubber composition of the present invention is less dependent on history due to deformation, and the structural calculation is performed for the building using the base isolation structure and the designer of the structure. It has a special effect that the design is easy.

  The rubber component of the rubber composition for laminated rubber of the seismic isolation structure of the present invention is not particularly limited. In addition to natural rubber (NR), styrene-butadiene rubber (SBR), butadiene rubber (BR), isoprene Examples thereof include rubber (IR), chloroprene rubber, butyl rubber (IIR), halogenated butyl rubber, ethylene-propylene rubber (EPR), fluorine rubber, silicone rubber, urethane rubber and the like. These rubber components may be used alone or in a combination of two or more. Among these rubber components, natural rubber and butadiene rubber are preferable, and 30% by mass or more of the rubber component is more preferably natural rubber.

  The rubber composition for laminated rubber of the seismic isolation structure of the present invention contains a fatty acid salt. As described above, the Malins effect can be suppressed by blending a fatty acid salt with the rubber composition for laminated rubber. Here, the compounding amount of the fatty acid salt is 0.1 parts by mass or more, preferably 3 parts by mass or less, and is in the range of 1.0 to 3.0 parts by mass with respect to 100 parts by mass of the rubber component. Is particularly preferred. If the blending amount of the fatty acid salt is less than 0.1 parts by mass with respect to 100 parts by mass of the rubber component, the Malin's effect cannot be sufficiently suppressed, whereas if it exceeds 3 parts by mass, the Mooney viscosity of the rubber composition is increased. It falls and the processability of a rubber composition falls. Moreover, if the compounding quantity of a fatty acid salt is 1.0 mass part or more, the Malins effect can fully be suppressed.

  The fatty acid salt is a salt of a fatty acid and a metal. Here, examples of the fatty acid constituting the fatty acid salt include oleic acid, stearic acid, and palmitic acid, and examples of the metal constituting the fatty acid salt include K, Na, Ca, Zn, Mg, Ba, and the like. It is done. Specific examples of the fatty acid salt include potassium oleate, potassium stearate, potassium palmitate, zinc oleate, zinc stearate, and zinc palmitate. Among these, potassium oleate and zinc oleate Potassium stearate and zinc stearate are preferred. These fatty acid salts may be used individually by 1 type, and 2 or more types may be mixed and used for them.

  The rubber composition for laminated rubber of the seismic isolation structure of the present invention is, for example, a compounding agent usually used in the rubber industry together with the fatty acid salt, for example, a filler, petroleum hydrocarbon, Normal compounding amount by appropriately selecting a vulcanizing agent, a hardened fatty acid such as stearic acid, zinc white, various process oils, a vulcanization accelerator, an anti-aging agent, a resin and the like within a range not impairing the object of the present invention. It can manufacture by mix | blending within the range of kneading | mixing, kneading | mixing, heating and extruding.

  Examples of the filler include carbon black and silica. In addition, the compounding quantity of a filler has the preferable range of 20-70 mass parts with respect to 100 mass parts of said rubber components, and the range of 25-65 mass parts is still more preferable.

Examples of the petroleum hydrocarbon include C ₉ aromatic unsaturated hydrocarbons such as α-methylstyrene, o-vinyltoluene, m-vinyltoluene, p-vinyltoluene, 1-pentene, 2-pentene, 2- C ₅ aliphatic unsaturated hydrocarbons such as methyl-1-butene, 3-methyl-1-butene, 2-methyl-2-butene, 2-methyl-1,3-butadiene, 1,3-pentadiene, etc. Can be mentioned.

  As the vulcanizing agent, sulfur generally used as a vulcanizing agent for rubber such as powdered sulfur, highly dispersible sulfur, insoluble sulfur and the like is preferable. In addition, the compounding quantity of this vulcanizing agent has the preferable range of 0.5-10.0 mass parts with respect to 100 mass parts of said rubber components, and the range of 1.0-6.0 mass parts is still more preferable.

  Examples of the process oil include naphthenic process oil, paraffinic process oil, and aromatic process oil.

  Examples of the vulcanization accelerator include N-cyclohexyl-2-benzothiazylsulfenamide (CZ), N, N-dicyclohexyl-2-benzothiazylsulfenamide (DZ), dibenzothiazyl disulfide (MBTS), Examples include diphenylguanidine (DPG). In addition, the compounding quantity of this vulcanization accelerator has the preferable range of 0.5-5 mass parts with respect to 100 mass parts of said rubber components.

  Examples of the antiaging agent include N-1,3-dimethylbutyl-N′-phenyl-p-phenylenediamine (6C), 2,2,4-trimethyl-1,2-dihydroquinoline polymer (TMDQ), 6 -Ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline (ETMDQ) and the like. In addition, the compounding quantity of this anti-aging agent has the preferable range of 0.5-5 mass parts with respect to 100 mass parts of said rubber components.

As the resin, a phenol resin, rosin resin, DCPD resins, C ₅ petroleum resins, C ₉ petroleum resins, alicyclic petroleum resins, C ₅ petroleum resins and C ₉ resin obtained by copolymerizing a petroleum resin , Xylene resin, terpene resin, ketone resin, polyester polyol resin and the like. In addition, the range of 5-60 mass parts is preferable with respect to 100 mass parts of said rubber components, and, as for the compounding quantity of this resin, the range of 5-40 mass parts is still more preferable.

  The rubber composition of the present invention is used for laminated rubber of seismic isolation structures. The rubber composition of the present invention is formed into a sheet shape, for example, and the obtained rubber sheet and a rigid plate having rigidity are alternately laminated to constitute a laminated rubber. The laminated rubber constitutes the main part of the seismic isolation structure, and when it receives a shearing force in the horizontal direction due to vibration, it can effectively absorb the vibration energy and quickly attenuate the vibration. it can. Hereinafter, a seismic isolation structure including a laminated rubber using the rubber composition of the present invention will be described in detail with reference to the drawings.

  A seismic isolation structure 1 shown in FIG. 1 is fixed to laminated rubber 4 in which rigid plates 2 having rigidity and elastic plates 3 having elasticity are alternately laminated, and to both ends (upper and lower ends) of the laminated rubber 4. Further, the outer peripheral surface of the laminated rubber 4 is covered with a covering material 6. In the present invention, the rubber composition of the present invention described above is used for the elastic plate 3.

  The rigid plate 2 and the elastic plate 3 constituting the laminated rubber 4 are firmly bonded by, for example, vulcanization adhesion or an adhesive. In the vulcanization adhesion, the rigid plate 2 and the unvulcanized rubber composition are laminated and then vulcanized, and the vulcanized product of the unvulcanized rubber composition becomes the elastic plate 3. Here, as the rigid plate 2, a metal plate such as a steel plate, a ceramic plate, a reinforced plastic plate such as FRP, or the like can be used.

  Further, the laminated rubber 4 may not be covered with the covering material 6, but when the outer peripheral surface of the laminated rubber 4 is covered with the covering material 6 as in the illustrated example, the laminated rubber 4 is exposed to rain from the outside. And the light does not reach, and the deterioration of the laminated rubber 4 due to oxygen, ozone and ultraviolet rays can be prevented. As the covering material 6, vulcanized rubber or the like can be used.

  And the seismic isolation structure using the rubber composition of the present invention for the elastic plate 3 of the laminated rubber 4 has a sufficiently low history dependency due to deformation and is easy to design because the Mullins effect is sufficiently suppressed. There is a special effect.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.

  The components shown in Tables 1 and 2 were kneaded with a Banbury mixer to prepare a rubber composition. In addition, after kneading stage A, kneading stage B was performed, and a rubber composition was prepared through two stages of kneading. Next, the Mooney viscosity, elastic modulus, and history dependency of the obtained rubber composition were measured by the following methods. The results are shown in Tables 1 and 2.

(1) Mooney viscosity Mooney viscosity [ML (1 + 4) 127 ° C] was measured according to JIS K6300-1.

(2) Elastic modulus The rubber composition was rolled to a thickness of 2 mm using a roll for rubber rolling to produce a rubber sheet. Next, one rectangular rubber sheet 7 obtained by punching the obtained rubber sheet into a size of 25 mm × 25 mm was produced, and this was applied to two iron plates 8 coated with an adhesive of 25 mm × 60 mm × thickness 2.3 mm. Thus, as shown in FIG. Next, vulcanization was performed in a state where the iron plate 8 and the surface of the rubber sheet 7 in contact with the iron plate 8 were adhered, and the iron plate 8 and the rubber sheet 7 were adhered to prepare a test sample. Next, the test sample is placed in a spring stiffness and loss energy measuring device (manufactured by Kakinomiya Seisakusho, model: EFH-26-8-10). Inside, 50%, 100%, and 250% shear strain was applied at a frequency of 0.2 Hz, and the elastic modulus at each shear strain was measured. In addition, the measurement was performed 3 times in total and the average value was calculated | required.

(3) History dependence By the above method, the elastic modulus measured at the first time was divided by the elastic modulus measured at the third time to obtain a ratio, which was used as an index of the history dependence of the elastic modulus. The closer the ratio is to 1, the smaller the difference between the elastic modulus measured at the first time and the elastic modulus measured at the third time, and the smaller the history dependence of the elastic modulus.

* 1 Natural rubber: RSS # 4
* 2 Carbon Black A: “Asahi Thermal” manufactured by Asahi Carbon Co., Ltd.
* 3 Hardened fatty acid: “FA-KR” manufactured by NOF Corporation
* 4 Zinc flower: “No. 3 Zinc flower” manufactured by Hakusui Chemical Industry Co., Ltd.
* 5 Petroleum hydrocarbons: Protowax 1 manufactured by Nippon Oil Corporation
* 6 Anti-aging agent 6C: “ANTIGENE 6C” manufactured by Sumitomo Chemical Co., Ltd.
* 7 Fatty acid salt: manufactured by Schill + Seilacher, “Struktol EF44”, a mixture of zinc oleate, potassium oleate, zinc stearate and potassium stearate * 8 Naphthenic oil: “Sun Refine 4240”
* 9 Zinc flower mixed sulfur: "Z sulfur" manufactured by Tsurumi Chemical
* 10 Vulcanization accelerator CZ: “Noxeller CZ” manufactured by Ouchi Shinsei Chemical Co., Ltd.
* 11 Butadiene rubber: Asahi Kasei, “Diene NF35R”
* 12 Carbon Black B: “Asahi # 80-N” manufactured by Asahi Carbon Co., Ltd.
* 13 Phenol resin: “Sumilite Resin 217” manufactured by Sumitomo Bakelite Co., Ltd.
* 14 Cyclopentadiene resin: “Quinton 1325” manufactured by Nippon Zeon Co., Ltd.
* 15 Polyol aromatic oligomer: “L5” manufactured by Fudou Co., Ltd.
* 16 Heavy Aroma Oil: “Diana Process Oil AH-58” manufactured by Idemitsu Kosan Co., Ltd.

  From Tables 1 and 2, it can be seen that by blending the fatty acid salt, the Malins effect is suppressed, and the hysteresis dependence of the elastic modulus, particularly, the hysteresis dependence of the elastic modulus at 250% shear strain is reduced.

  From the results of Examples 4 and 8, it can be seen that when the fatty acid salt is added in an amount of more than 3 parts by mass, the Mooney viscosity of the rubber composition becomes too low, and the processability decreases. From this, it is understood that the blending amount of the fatty acid salt is preferably 3 parts by mass or less with respect to 100 parts by mass of the rubber component from the viewpoint of processability.

DESCRIPTION OF SYMBOLS 1 Seismic isolation structure 2 Rigid board 3 Elastic board 4 Laminated rubber 5 Flange board 6 Coating material 7 Rectangular rubber sheet 8 Iron plate

Claims (3)

Per 100 parts by mass of the rubber component, Ri name by blending fatty acid salt 0.1 part by mass or more,
A rubber composition for laminated rubber having a base-isolated structure, wherein the fatty acid salt contains potassium oleate .   The rubber composition for laminated rubber of a seismic isolation structure according to claim 1, wherein the amount of the fatty acid salt is 3 parts by mass or less with respect to 100 parts by mass of the rubber component. Wherein the fatty acid salt is potassium oleate, zinc oleate, Rubber The rubber composition for a seismic isolation structure according to claim 1, characterized in that it comprises potassium stearate and zinc stearate.

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