JP2009243652A - High damping laminated body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high damping laminated body with superior appearance after excitation while maintaining performance as a rubber bearing body. <P>SOLUTION: In the high damping laminated body 1, rubber compositions 3 for the high damping laminated body and hard plates 2 are alternately laminated, and it has coating rubber 4 on an outer circumference side face. The coating rubber 4 includes a two layer structure of an inner rubber layer 4a and an outer rubber layer 4b. The inner rubber layer 4a is formed of a rubber composition with breaking elongation of 700% or more and hardness of 65 or less, the outer rubber layer 4b is formed of a rubber composition with breaking elongation of 600% or more and hardness of 75 or more, and a difference of hardness between the rubber composition forming the inner rubber layer 4a and the rubber composition forming the outer rubber layer 4b is 15 or more. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a high attenuation laminate.

  In recent years, seismic isolation devices, seismic isolation devices, seismic isolation devices and the like are rapidly spreading as vibration energy absorbing devices. As such an apparatus, for example, a laminated rubber bearing body in which flanges are fixed to the upper and lower surfaces of a laminated body in which rubber sheets and iron plates are alternately laminated is known.

  The laminated rubber support is generally composed of a rubber material having a high shear modulus, and the outer peripheral side surface of the laminated body is the same as the main rubber or an outer layer with weather resistance added (generally, EPDM or the like). In Japanese Patent Application Laid-Open No. 2003-228867, the present applicant has disclosed that “a laminate is formed by alternately laminating rubber sheets and iron plates and laminating an outer layer rubber on the outer peripheral side surface of the laminate. In the rubber bearing body, a laminated rubber bearing body is proposed in which the rubber material of the outer layer rubber is a material larger than the breaking elongation of the rubber sheet of the laminated body.

JP 11-77889 A

  However, the laminated rubber support described in Patent Document 1 has an outer layer rubber (hereinafter referred to as “coated rubber” in the present invention) by the rubber sheet of the laminated body protruding from between the iron plates after vibration. As shown in the photograph (see FIG. 3) of the laminate produced in Comparative Example 1 to be described later, it was found that there was a problem that the appearance was inferior even though there was no problem in performance.

  Therefore, an object of the present invention is to provide a high-attenuation laminate that retains the performance as a rubber bearing body and is excellent in appearance after vibration.

As a result of diligent investigations to solve the above-mentioned problems, the present inventor has adopted a rubber composition (vulcanized) that forms a two-layer structure of an inner rubber layer and an outer rubber layer as the coating rubber formed on the outer peripheral side surface. It was found that by setting the elongation at break, hardness, and hardness difference of the product) to a specific value, a high-attenuation laminate excellent in appearance after vibration can be obtained while maintaining the performance as a rubber support, The present invention has been completed.
That is, the present invention provides the following (1) to (4).

(1) A high-attenuation laminate in which a rubber composition for a high-attenuation laminate and a hard plate are alternately laminated, and a coating rubber is provided on the outer peripheral side surface,
The coated rubber has a two-layer structure of an inner rubber layer and an outer rubber layer,
The inner rubber layer is formed from a rubber composition having a breaking elongation of 700% or more and a hardness of 65 or less,
The outer rubber layer is formed from a rubber composition having an elongation at break of 600% or more and a hardness of 75 or more,
A high-damping laminate having a hardness difference of 15 or more between the rubber composition forming the inner rubber layer and the rubber composition forming the outer rubber layer.

  (2) The high attenuation laminate according to (1) above, wherein the ratio of the thickness of the inner rubber layer to the thickness of the outer rubber layer is 2: 8 to 8: 2.

  (3) The above (1) or (1), wherein the rubber composition forming the outer rubber layer contains 100 parts by mass of a diene rubber, 60 to 90 parts by mass of carbon black, and 15 to 50 parts by mass of petroleum resin. The high attenuation laminate according to 2).

  (4) The above (1) to (3), wherein the rubber composition forming the inner rubber layer contains 100 parts by mass of a diene rubber, 10 to 55 parts by mass of carbon black, and 20 parts by mass or less of petroleum resin. The high attenuation laminate according to any one of the above.

  As will be described below, according to the present invention, it is possible to provide a high-attenuation laminate that retains the performance as a rubber bearing and is excellent in appearance after vibration.

The present invention is described in detail below.
The high attenuation laminate of the present invention (hereinafter also referred to as “the laminate of the present invention”) is a high attenuation laminate in which a rubber composition for a high attenuation laminate and a hard plate are alternately laminated and a coating rubber is provided on the outer peripheral side surface. A laminated body, wherein the covering rubber has a two-layer structure of an inner rubber layer and an outer rubber layer,
The inner rubber layer is formed from a rubber composition (hereinafter also referred to as “inner rubber composition”) having an elongation at break of 700% or more and a hardness of 65 or less,
The outer rubber layer is formed from a rubber composition having a breaking elongation of 600% or more and a hardness of 75 or more (hereinafter also referred to as “outer layer rubber composition”).
A high attenuation laminate in which the difference in hardness between the rubber composition forming the inner rubber layer and the rubber composition forming the outer rubber layer is 15 or more.
Next, the rubber composition for a high attenuation laminate and the hard plate, the inner layer rubber composition and the outer layer rubber composition constituting the laminate of the present invention will be described.

[Rubber composition for highly attenuated laminate]
In the present invention, the rubber composition for the high attenuation laminate is not particularly limited, and for example, a rubber composition forming a rubber layer (rubber sheet) constituting a conventionally known laminated rubber support can be used.
Specifically, such a rubber composition contains, for example, a diene rubber; an inorganic filler such as carbon black or silica; a petroleum resin; an additive such as a vulcanizing agent or a vulcanization accelerator; A highly damped rubber composition may be mentioned.

<Diene rubber>
The diene rubber is not particularly limited, and specific examples thereof include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene copolymer rubber (SBR), and acrylonitrile-butadiene copolymer. Examples thereof include rubber (NBR), butyl rubber (IIR), halogenated butyl rubber (Br-IIR, Cl-IIR), chloroprene rubber (CR) and the like.
Among these, NR is preferable because of a good balance between physical properties such as modulus, tensile strength, elongation at break, and workability, and the reason for further reducing the temperature dependence of damping property and shear modulus. To BR.

  In the present invention, the above diene rubbers may be used alone or in combination of two or more. As a suitable combination of the above diene rubbers when two or more kinds are used in combination, the rubber components are excellent in compatibility, processability, green strength and vulcanized physical properties, and the temperature dependence and damping of the high damping laminate. From the viewpoint of securing the property, for example, NR and BR, IR and BR, NR, IR and BR can be mentioned. Among these, NR and BR are preferable because they are more excellent in this characteristic. These mixing ratios are not particularly limited.

<Inorganic filler>
The inorganic filler is not particularly limited, and specific examples thereof include carbon black, silica, T-clay, kaolin clay, wax stone clay, sericite clay, calcined clay, diatomaceous earth, heavy calcium carbonate, magnesium carbonate. , Aluminum hydroxide, barium sulfate, talc, aggregates of quartz and kaolinite, and the like.
Of these, carbon black and silica are preferred because they have excellent rubber reinforcing effects and are excellent in the modulus, tensile strength, elongation at break, and shear modulus of the laminate of the present invention.

(Carbon black)
In the present invention, conventionally known carbon black can be used.

In the present invention, carbon black having a CTAB adsorption specific surface area of 100 m ² / g or more is preferably used, and carbon black of 110 to 370 m ² / g is more preferably used.
When the CTAB adsorption specific surface area is in the range of 100 m ² / g or more, the damping property of the laminate of the present invention obtained can be maintained higher.
Here, the CTAB adsorption specific surface area is a value obtained by measuring the surface area that carbon black can be used for adsorption with rubber molecules by adsorption of CTAB (cetyltrimethylammonium bromide).
Examples of such carbon black include SAF, ISAF, and HAF. The CATB adsorption specific surface area can be measured by the method described in ASTM D3765-80.

In this invention, it is preferable that content of carbon black in the rubber composition for highly attenuated laminated bodies is 40 to 75 parts by mass, and 50 to 75 parts by mass with respect to 100 parts by mass of the diene rubber. More preferred.
When the content of carbon black is within this range, the resulting laminate of the present invention has high damping properties and good shear modulus.

(silica)
In the present invention, conventionally known silica can be used.
Specific examples of silica include fumed silica, calcined silica, precipitated silica, pulverized silica, and fused silica.
Silica preferably has an average aggregate particle diameter of 5 to 50 μm, more preferably 5 to 30 μm.

In this invention, it is preferable that content of the silica in the rubber composition for highly attenuated laminated bodies is 5-35 mass parts with respect to 100 mass parts of diene rubbers, and it is 10-30 mass parts. More preferred.
When the content of silica is within this range, the resulting laminate of the present invention has high damping properties and good shear modulus.

<Petroleum resin>
The petroleum resin is not particularly limited, and specific examples thereof include C5 aliphatic unsaturated hydrocarbon polymer, C9 aromatic unsaturated hydrocarbon polymer, and C5 aliphatic unsaturated hydrocarbon. And a copolymer of C9 aromatic unsaturated hydrocarbon.

Specific examples of the C5 aliphatic unsaturated hydrocarbon include, for example, 1-pentene, 2-pentene, 2-methyl-1-butene contained in a C5 fraction obtained by thermal decomposition of naphtha, Olefinic hydrocarbons such as 3-methyl-1-butene and 2-methyl-2-butene; 2-methyl-1,3-butadiene, 1,2-pentadiene, 1,3-pentadiene, 3-methyl-1 , 2-olefin hydrocarbons such as 2-butadiene;
These can be polymerized or copolymerized in the presence of a suitable catalyst. Here, the C5 aliphatic unsaturated hydrocarbon polymer is a co-polymer of a single C5 aliphatic unsaturated hydrocarbon homopolymer and two or more C5 aliphatic unsaturated hydrocarbons. It refers to any polymer.

Specific examples of the C9 aromatic unsaturated hydrocarbon include, for example, α-methylstyrene, o-vinyltoluene, m-vinyltoluene, p contained in a C9 fraction obtained by thermal decomposition of naphtha. -Vinyl-substituted aromatic hydrocarbons such as vinyltoluene.
These can be polymerized or copolymerized in the presence of a suitable catalyst. Here, the C9 aromatic unsaturated hydrocarbon polymer is a co-polymer of a single C9 aromatic unsaturated hydrocarbon homopolymer and two or more C9 aromatic unsaturated hydrocarbons. It refers to any polymer.

In addition, a copolymer of a C5 aliphatic unsaturated hydrocarbon and a C9 aromatic unsaturated hydrocarbon is a C9 aromatic unsaturated hydrocarbon in that the softening point of the copolymer is high. What a unit is 60 mol% or more is preferable, and what is 90 mol% or more is more preferable.
A copolymer of a C5 aliphatic unsaturated hydrocarbon and a C9 aromatic unsaturated hydrocarbon can be copolymerized in the presence of a suitable catalyst.

  The above petroleum resin has a molecular weight and a double bond reactivity that affect the physical properties of the diene rubber, so that the softening point (JIS K2207) is preferably 100 ° C. or higher, more preferably 120 ° C. or higher. preferable.

In this invention, it is preferable that content of the petroleum resin in the rubber composition for highly attenuated laminated bodies is 5-50 mass parts with respect to 100 mass parts of diene rubbers, and is 10-45 mass parts. Is more preferable.
When the content of the petroleum resin is within this range, the obtained laminate of the present invention maintains high damping properties, has low temperature dependence, and is stable in damping properties and shear modulus against long-term repeated shear deformation. It will be a thing.

<Additives>
Examples of the additive include a vulcanizing agent, a vulcanization accelerator, an anti-aging agent, a plasticizer, a softening agent, a vulcanization aid, a flame retardant, a weathering agent, and a heat resistance agent.
Specific examples of the vulcanizing agent include sulfur and zinc oxide; organic sulfur-containing compounds such as TMTD; organic peroxides such as dicumyl peroxide; and the like.
Specific examples of the vulcanization accelerator include sulfenamides such as N-cyclohexyl-2-benzothiazole sulfenamide (CBS); thiazoles such as mercaptobenzothiazole; tetramethylthiuram monosulfide and the like. Thiurams; stearic acid; and the like.
Specific examples of the antiaging agent include ketone / amine condensates such as TMDQ; amines such as DNPD; monophenols such as styrenated phenol; and the like.
Specific examples of the plasticizer include phthalic acid derivatives (for example, DBP, DOP and the like), sebacic acid derivatives (for example, DBS and the like) monoesters, and the like.
Specific examples of the softening agent include paraffinic oil (process oil).

  The production (preparation) method of the rubber composition for a highly attenuated laminate is not particularly limited. For example, the unvulcanized rubber composition containing the above-described components is kneaded using a known method and apparatus. Can be prepared.

[Hard plate]
In the present invention, the hard plate is not particularly limited, and for example, an iron plate (general structural steel plate, cold rolled steel plate, etc.) constituting a conventionally known laminated rubber bearing can be used.

[Inner rubber composition]
The inner rubber layer is a rubber layer constituting an inner layer of a two-layered covering rubber that covers the outer peripheral side surface of the laminate of the present invention, and is formed from a rubber composition having a breaking elongation of 700% or more and a hardness of 65 or less. It is formed.

In the present invention, the rubber composition forming the inner rubber layer is not particularly limited as long as it has a rupture elongation after vulcanization of 700% or more and a hardness of 65 or less, but the hardness is 40 or more. Specifically, a rubber composition containing 100 parts by mass of a diene rubber, 10 to 55 parts by mass of carbon black, and 20 parts by mass or less of petroleum resin is preferably exemplified.
In addition, from the viewpoint of approaching the vulcanization rate of the outer layer rubber composition described later, the content of the vulcanizing agent and the vulcanization accelerator is less than the content in the outer layer rubber composition described later, and contains a scorch inhibitor. preferable.
Here, the composition components such as diene rubber and carbon black are the same as those contained in the rubber composition for a high attenuation laminate described above.

  The method for producing (preparing) the inner layer rubber composition is not particularly limited. For example, an unvulcanized rubber composition containing the above-described components can be prepared by kneading using a known method and apparatus.

[Outer rubber composition]
The outer rubber layer is a rubber layer constituting an outer layer of a two-layered covering rubber that covers the outer peripheral side surface of the laminate of the present invention, and is formed from a rubber composition having a breaking elongation of 600% or more and a hardness of 75 or more. It is formed.

  In the present invention, the rubber composition forming the outer rubber layer is not particularly limited as long as it has a rupture elongation after vulcanization of 600% or more and a hardness of 75 or more, but the hardness is 90 or less. Specifically, specifically, a composition similar to the above-described rubber composition for highly attenuated laminates, specifically, 100 parts by mass of diene rubber, 60 to 90 parts by mass of carbon black, and petroleum resin A rubber composition containing 15 to 50 parts by mass is preferably exemplified.

  Although the manufacturing (preparation) method of an outer layer rubber composition is not specifically limited, For example, the unvulcanized rubber composition which mix | blended each component mentioned above can be prepared by kneading | mixing etc. using a well-known method and apparatus.

  Here, the values of the elongation at break and the hardness in the inner layer rubber composition and the outer layer rubber composition described above are measured values of the rubber composition after vulcanization, and in the present invention, the values measured by the following method are used. is there.

<Elongation at break>
The unvulcanized rubber composition was vulcanized for 45 minutes under a surface pressure of 3.0 MPa using a press molding machine at 148 ° C. to prepare a vulcanized sheet having a thickness of 2 mm. A JIS No. 3 dumbbell-shaped test piece was punched from this sheet, a tensile test at a tensile speed of 500 mm / min was conducted in accordance with JIS K6251-2004, and elongation (E _B ) [%] at the time of cutting was measured at room temperature. .

<Hardness>
About the test piece similar to the said breaking elongation, Shore A hardness was measured according to the "type A durometer hardness test" of JISK6253-1997.

  In the present invention, the difference in hardness between the inner rubber composition and the outer rubber composition is 15 or more, preferably 20 or more.

By having such a two-layered covering rubber composed of the inner layer rubber composition and the outer layer rubber composition, the laminate of the present invention maintains the performance as a rubber bearing body, and the appearance after vibration is applied. Also excellent.
This is because the outer layer rubber composition suppresses the force of the above-described rubber composition for a high-damping laminate from protruding from between the above-mentioned hard plates, and this rubber layer is constrained (adhered) by the hard plate by the inner-layer rubber composition. This is thought to be because the movement of the part that is present can be relaxed.

Furthermore, in the present invention, the ratio of the thickness of the inner rubber layer to the thickness of the outer rubber layer is preferably 2: 8 to 8: 2, and more preferably 2: 8 to 6: 4. preferable.
When the ratio between the thickness of the inner rubber layer and the thickness of the outer rubber layer is within this range, the appearance of the obtained laminate of the present invention after vibration is further improved.

  The laminate of the present invention has a two-layer structure in which the above-described rubber composition for a high-attenuation laminate and a hard plate are alternately laminated, and the inner surface rubber composition and the outer layer rubber composition are formed on the outer peripheral side surface. It is a high-attenuation laminated body with rubber, and is a structure used for bridge support and building base isolation.

In FIG. 1, the cross-sectional schematic of the high attenuation | damping laminated body showing an example of the embodiment of the laminated body of this invention is shown.
In FIG. 1, the code | symbol 1 represents a high attenuation | damping laminated body (seismic isolation laminated body), the code | symbol 2 represents a hard board, and the code | symbol 3 represents the rubber composition for high attenuation | damping laminated bodies. Reference numeral 4 represents a coated rubber, of which reference numeral 4a represents an inner rubber layer, and reference numeral 4b represents an outer rubber layer.

As shown in FIG. 1 as an example, the high-damping laminate 1 of the present invention is obtained by alternately laminating the rubber composition 3 for the high-damping laminate and the hard plate 2 described above, and the inner-layer rubber composition described above on the outer peripheral side surface. And the outer rubber layer 4b composed of the outer rubber composition described above.
Further, the high attenuation laminate 1 may be configured by providing an adhesive layer between the rubber composition 3 for the high attenuation laminate and the hard plate 2, or directly vulcanized without providing the adhesive layer. May be configured.
Similarly, the high damping laminate 1 includes an adhesive layer between the hard plate 2 and the rubber composition 3 for the high damping laminate and the inner rubber layer 4a and between the inner rubber layer 4a and the outer rubber layer 4b. May be provided, or may be directly vulcanized without providing an adhesive layer.

In FIG. 1, the high-attenuation laminate 1 of the present invention is shown in a state in which a rubber composition 3 for a high-attenuation laminate and a hard plate 2 are alternately laminated. The composition 3 may have a structure in which two or more layers are laminated.
In addition, FIG. 1 shows an example of a total of 13 layers of 7 layers for the rubber composition 3 for the high attenuation laminate and 6 layers for the hard plate 2, but the high attenuation laminate of the high attenuation laminate 1 of the present invention. The number of layers of the body rubber composition 3 and the hard plate 2 is not limited to this, and can be arbitrarily set according to the intended use, required characteristics, and the like.
Furthermore, the size of the high attenuation structure 1 of the present invention, the overall thickness, the layer thickness of the rubber composition 3 for the high attenuation laminate of the present invention, the thickness of the hard plate, etc. It can be set arbitrarily according to the required characteristics.

In order to produce the laminate of the present invention, the rubber composition for a high attenuation laminate described above is molded into a sheet and then vulcanized to obtain a sheet-like rubber composition, and then a layer containing an adhesive is formed. It may be provided and laminated alternately with the hard plate, or the rubber composition for the highly damped laminate of the present invention that has not been vulcanized in advance is formed into a sheet shape and laminated alternately with the hard plate and then heated. The vulcanization and adhesion may be performed simultaneously.
Similarly, for the coated rubber, after laminating the rubber composition for the high attenuation laminate and the hard plate, the upper and lower surfaces are fixed with a flange or the like, and the inner layer rubber composition and the outer layer rubber composition described above are attached to the outer peripheral side surface. It can be provided by a method of winding a sheet-shaped product in this order and vulcanizing.

  As long as the high-damping laminate is used as a vibration energy absorber, its use, application conditions, and the like are not particularly limited. Among these, since it has the above-described excellent characteristics, it is preferably used as a vibration energy absorbing device for buildings. For example, a vibration energy absorbing device for various types of seismic isolation, vibration isolation and vibration isolation (more specifically, Is suitably used for, for example, support of road bridges, bridges, building base isolation, and detached base isolation).

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely according to an Example, this invention is not limited to the following Example.

(Preparation of rubber composition for highly attenuated laminate)
Each compound was blended so as to have the composition shown in Table 1 below (unit: parts by mass) and kneaded for 5 minutes with a B-type Banbury mixer to prepare a rubber composition for an unvulcanized high-attenuation laminate. .
Next, the prepared unvulcanized rubber composition for a high attenuation laminate was rolled to produce a sheet-like material having a width of 900 mm, a length of 900 mm, and a thickness of 5 mm.

The following were used for each component in Table 1.
・ Natural rubber: STR20, manufactured by TECK BEE HANG ・ Butadiene rubber: Nipol BR1220, manufactured by Nippon Zeon ・ Carbon black: Diamond Black I, manufactured by Mitsubishi Chemical ・ Petroleum resin: High Resin # 120 (softening point 120 ° C., manufactured by Toho Chemical Co., Ltd.) )
・ Soft clay: Union Clay RC-1, manufactured by Takehara Chemical Co., Ltd. ・ Silica: Nip Seal VN3, manufactured by Tosoh Silica Co., Ltd. ・ Aroma oil: Kyoishi Process X-140, manufactured by Kyodo Oil Co., Ltd. ・ Sulfur: Powdered sulfur, Hosoi Chemical Industry・ Vulcanization accelerator: Noxeller CZ, Ouchi Shinsei Chemical Co., Ltd.

(Preparation of unvulcanized outer layer rubber composition and inner layer rubber composition)
Each compound was blended so as to have the composition shown in Table 2 below (unit: parts by mass) and kneaded in a B-type Banbury mixer for 5 minutes, and the unvulcanized outer layer rubber composition and inner layer rubber composition were respectively obtained. Prepared.
Next, the prepared unvulcanized outer layer rubber composition and inner layer rubber composition were rolled, and sheet-like materials having the sizes shown below were produced according to Examples and Comparative Examples.
The rupture elongation and hardness of the vulcanized outer layer rubber composition and inner layer rubber composition are as shown in Table 2.

Example 1
A high-damping laminate was produced using each rubber composition after rolling.
Specifically, three layers of a rubber layer (width 900 mm × length 900 mm × thickness 35 mm) formed by laminating seven sheets of the rubber composition for a high attenuation laminate after rolling and an iron plate (width 900 mm) × 2 layers of length 900 mm × thickness 4.5 mm) are alternately laminated, and one iron plate (width 900 mm × length 900 mm × thickness 32 mm) is laminated on the top and bottom of these laminates. A laminated body (width 900 mm × length 900 mm × thickness 178 mm) was produced.
Next, the rolled inner layer rubber composition (width 178 mm × thickness 5 mm) and outer layer rubber composition (width 178 mm × thickness 5 mm) were each wound in this order on the outer peripheral side surface of the produced laminate.
Thereafter, press vulcanization was carried out at 135 ° C. for 600 minutes to produce a highly attenuated laminate. Note that the ratio of the thickness of the inner rubber layer to the thickness of the outer rubber layer of the produced high-damping laminate was 1: 1.

(Example 2)
A highly attenuated laminate was produced in the same manner as in Example 1 except that the rolled inner layer rubber composition (width 178 mm × thickness 3 mm) and outer layer rubber composition (width 178 mm × thickness 7 mm) were used. The ratio of the thickness of the inner rubber layer and the thickness of the outer rubber layer of the produced highly-damped laminate was 3: 7.

(Example 3)
A highly attenuated laminate was produced in the same manner as in Example 1 except that the rolled inner layer rubber composition (width 178 mm × thickness 7 mm) and outer layer rubber composition (width 178 mm × thickness 3 mm) were used. Note that the ratio of the thickness of the inner rubber layer to the thickness of the outer rubber layer of the produced high-damping laminate was 7: 3.

(Comparative Example 1)
A high-attenuation laminate was produced in the same manner as in Example 1, except that the inner layer rubber composition was not used and the outer layer rubber composition (width 178 mm × thickness 5 mm) was wound around the outer peripheral side surface by two rounds.

(Comparative Example 2)
A high-attenuation laminate was produced in the same manner as in Example 1 except that the outer-layer rubber composition was not used and the inner-layer rubber composition (width 178 mm × thickness 5 mm) was wound twice on the outer peripheral side surface.

(Comparative Example 3)
A highly attenuated laminate was produced in the same manner as in Comparative Example 2 except that the inner rubber composition having the composition shown in Table 2 below was used.

  About each produced high attenuation | damping laminated body, the external appearance after vibration was evaluated by the method shown below. The results are shown in Table 2.

<Appearance>
In the state where a vertical load (4200 kN) corresponding to the dead load was applied to each of the produced high attenuation laminates, a deformation frequency of 0.005 Hz and a measurement temperature of 23 ° C. were used, and a 175% strain of 11 was applied. Added twice.
After that, the strain and vertical load are released, the surface of the coated rubber is visually confirmed, and a smooth surface is evaluated as “Excellent” by the appearance after vibration. Those that can be confirmed were evaluated as “Δ” as being excellent in appearance after vibration, and those having streaky wrinkles on the surface were evaluated as “x” as being inferior in appearance after vibration.
In addition, the photograph which shows the external appearance of the coated rubber | gum after vibration of Example 1, the comparative example 1, and the comparative example 3 is shown to FIGS.

Among the components in Table 2, the following components were used as those different from the components in Table 1.
・ Zinc oxide: Zinc Hana 3 manufactured by Shodo Chemical Co., Ltd. ・ Stearic acid: LUNAC YA, manufactured by Kao Corporation ・ Anti-aging agent: 6C, manufactured by Seiko Chemical Co., Ltd. ・ Wax: Sunnoc, manufactured by Ouchi Shinsei Chemical Co., Ltd. ・ Scorch inhibitor : Retarder CTP, manufactured by Ouchi Shinsei Chemical

  As is apparent from Table 2, the coating rubber formed on the outer peripheral side surface has a two-layer structure of an inner rubber layer and an outer rubber layer, and the elongation at break, hardness, and hardness of the rubber composition (vulcanized product) forming these layers It was found that by setting the hardness difference to a specific value, a highly attenuated laminate having excellent appearance after vibration can be obtained.

FIG. 1 is a schematic cross-sectional view of a highly attenuated laminate that represents an example of an embodiment of the laminate of the present invention. FIG. 2 is a photograph showing the appearance of the coated rubber after the vibration of the highly attenuated laminate produced in Example 1. FIG. 3 is a photograph showing the appearance of the coated rubber after the vibration of the highly attenuated laminate produced in Comparative Example 1. FIG. 4 is a photograph showing the appearance of the coated rubber after vibration of the high-attenuation laminate produced in Comparative Example 3.

Explanation of symbols

1 High attenuation laminate (Seismic isolation laminate)
2 Hard plate 3 Rubber composition for high damping laminate 4 Cover rubber 4a Inner rubber layer 4b Outer rubber layer

Claims (4)

A rubber composition for a high attenuation laminate and a hard plate are alternately laminated, and a high attenuation laminate having a coating rubber on the outer peripheral side surface,
The covering rubber has a two-layer structure of an inner rubber layer and an outer rubber layer,
The inner rubber layer is formed from a rubber composition having an elongation at break of 700% or more and a hardness of 65 or less;
The outer rubber layer is formed from a rubber composition having an elongation at break of 600% or more and a hardness of 75 or more,
A highly attenuated laminate in which a difference in hardness between the rubber composition forming the inner rubber layer and the rubber composition forming the outer rubber layer is 15 or more.   The high attenuation laminate according to claim 1, wherein a ratio of a thickness of the inner rubber layer to a thickness of the outer rubber layer is 2: 8 to 8: 2.   The high rubber according to claim 1 or 2, wherein the rubber composition forming the outer rubber layer contains 100 parts by mass of a diene rubber, 60 to 90 parts by mass of carbon black, and 15 to 50 parts by mass of petroleum resin. Damped laminate.   The rubber composition for forming the inner rubber layer contains 100 parts by mass of a diene rubber, 10 to 55 parts by mass of carbon black, and 20 parts by mass or less of petroleum resin. High damping laminate.