JP5250940B2 - Rubber composition for high damping bearing and high damping bearing - Google Patents

Description

  The present invention relates to a rubber composition for a high damping laminate and a high damping support.

  In recent years, seismic energy absorbing devices, that is, seismic isolation devices, seismic isolation devices, seismic isolation devices, and the like are rapidly spreading. For example, seismic isolation rubber is used for bridge support and base isolation of buildings. The seismic isolation laminated rubber is a laminated body in which a rubber composition and a hard plate are usually laminated and bonded alternately in a few layers to a dozen layers. Such seismic isolation laminated rubber has a hardness that can support a building in the vertical direction and a softness that gives a gentle reciprocating motion to the building during an earthquake in the horizontal direction. In other words, the laminated rubber for seismic isolation reduces the shear rigidity and acts so as to shift the natural vibration period of the building from the vibration period of the earthquake, thereby greatly reducing the acceleration that the building receives from the earthquake. The laminated rubber for seismic isolation is required to have a high damping property (attenuating vibration energy by converting vibration into more heat) and exhibiting a desired shear modulus.

Examples of the rubber composition used for the seismic isolation laminated rubber include those described in Patent Documents 1 to 4.
The rubber composition for a seismic isolation laminate described in Patent Document 1 is a block copolymer in which the glass transition temperature of polystyrene and vinyl-polyisoprene is −15 ° C. or more with respect to 100 parts by mass of rubber mainly composed of natural rubber. A rubber composition for a base-isolated laminate comprising 5 to 30 parts by mass of a polymer, 15 to 60 parts by mass of a petroleum resin, and 50 to 90 parts by mass of fine carbon black. The rubber composition for a seismic isolation laminate is described as being excellent in vibration energy absorption and long-term durability.
The high-damping rubber composition described in Patent Document 2 includes 15 to 60 parts by mass of petroleum resin, fine particle carbon black, and 100 parts by mass of rubber containing 50 parts by mass or more of natural rubber and / or isoprene rubber. The high-damping rubber composition is characterized in that it contains 60 to 95 parts by mass of silica in total, and a mass part ratio of the fine particle carbon black to the silica is in a range of 95/5 to 75/25. It is described that the high damping rubber composition has a low elastic modulus and is excellent in damping performance, fracture characteristics and the like.
The rubber composition for high damping bearing described in Patent Document 3 has 60 to 100 parts by mass of carbon black having a CTAB adsorption specific surface area of 120 m ² / g or more with respect to 100 parts by mass of the rubber component, and a reinforcing effect. It is a rubber composition for high damping bearings characterized by containing 10 parts by mass or more of an inorganic filler with a low content. It is described that the rubber composition for high damping bearings has a high damping rate and a low strain dependency between the damping rate and the shear modulus.
Seismic isolation laminate-body rubber composition described in Patent Document 4, 1) diene rubber, 2) with a CTAB specific surface area of 120~220m ² / g, CTAB specific surface area (m ² / g) / so The diene rubber comprising carbon black having an elemental adsorption amount (mg / g) of 0.90 or less, and 3) a terpene resin and / or an alicyclic saturated hydrocarbon resin having a softening point of 70 to 150 ° C. For the seismic isolation laminate, the content of the carbon black is 40 to 160 parts by mass and the content of the terpene resin and / or alicyclic saturated hydrocarbon resin is 1 to 60 parts by mass with respect to 100 parts by mass. It is a rubber composition. It is described that the rubber composition for a seismic isolation laminate has excellent mechanical properties and damping rate, and the temperature dependence of shear modulus is small and has stable shear elasticity throughout the year.

  Moreover, when the laminated rubber for seismic isolation is repeatedly subjected to shear deformation over a long period of time, there is a problem that the shear elastic modulus increases and the damping property decreases. Therefore, in recent years, in addition to (1) high damping properties and (2) excellent shear modulus as properties of the rubber for high damping bearings, (3) laminated rubber for seismic isolation that has not been conventionally required Even when shear deformation is repeated repeatedly, it is also required that the shear modulus is stable.

  On the other hand, the present inventor has described, as a high-damping bearing rubber composition that can stably exhibit high damping and excellent rigidity even when repeatedly subjected to shear deformation, “100 parts by mass of a rubber component and an aggregate of quartz and kaolinite. A high-damping bearing rubber composition containing 5 to 55 parts by mass and 10 to 55 parts by mass of petroleum resin has been proposed (see Patent Document 5).

Japanese Patent Laid-Open No. 10-110063 International Publication No. 98/16580 Pamphlet JP 2002-20546 A Japanese Patent Laid-Open No. 2004-27080 Japanese Patent Laying-Open No. 2005-206654

  However, the conventional high damping bearing rubber composition as described in Patent Documents 1 to 4 satisfies all of the other required characteristics (1) and (2) as well as the new required characteristics (3) described above. I couldn't. In addition, the rubber composition for high damping bearing described in Patent Document 5 can stably exhibit high damping and excellent rigidity even when repeatedly subjected to shear deformation. There was room for further improvement in stability.

  In addition, when carbon black with a small particle size is blended for the purpose of imparting damping properties to the rubber composition for high damping bearings, the small particle size carbon black has low dispersibility in rubber and the required shear modulus There was a problem that could not be obtained.

Therefore, the present invention provides a rubber composition for a high-damping laminate that has high damping properties, excellent shear modulus, little increase in shear modulus against long-term repeated shear deformation, and can exhibit stable characteristics over a long period of time. The purpose is to provide goods.
The present invention also provides a highly damped support body that has high damping properties, excellent shear modulus, little increase in shear modulus against long-term repeated shear deformation, and can exhibit stable characteristics over a long period of time. For the purpose.

  When the present inventor blends 50 to 90 parts by mass of carbon black having specific colloidal characteristics with 100 parts by mass of the diene rubber, the damping is high, the shear modulus is excellent, and the shear against long-term repeated shear deformation is high. The present invention was completed by finding that the rubber composition for a high-attenuation laminate is capable of exhibiting stable characteristics over a long period of time with little increase in elastic modulus.

That is, the present invention provides the following (1) to (4).
(1) 100 parts by mass of a diene rubber,
Nitrogen adsorption specific surface area of 150 to 300 m ² / g and, DBP absorption of 115cm ^3/100 g or less, and carbon black 50 the difference between the nitrogen adsorption specific surface area and CTAB adsorption specific surface area of 5~34m ² / g A rubber composition for high damping bearings, comprising ~ 90 parts by mass.
(2) The rubber composition for high damping bearings according to (1), further comprising a petroleum resin.
(3) The rubber composition for high damping bearing according to (2), wherein the content of the petroleum resin is 5 to 45 parts by mass with respect to 100 parts by mass of the diene rubber.
(4) A high damping support obtained by alternately laminating the rubber composition for high damping support according to any one of (1) to (3) and a hard plate.

The rubber composition for high damping bearings of the present invention has high damping properties, excellent shear modulus, little increase in shear modulus against long-term repeated shear deformation, and can exhibit stable characteristics over a long period.
In addition, the high damping support of the present invention has high damping properties, excellent shear modulus, little increase in shear modulus against long-term repeated shear deformation, and can exhibit stable characteristics over a long period.

Hereinafter, the present invention will be described in more detail.
The rubber composition for high damping bearings of the present invention (hereinafter also referred to as “the composition of the present invention”) has 100 parts by mass of a diene rubber, a nitrogen adsorption specific surface area of 150 to 300 m ² / g, and DBP absorption. amount 115cm ^3/100 g or less, and the difference is 5~34m ² / g high damping support for a rubber composition containing a carbon black from 50 to 90 parts by weight which is between the nitrogen adsorption specific surface area and CTAB adsorption specific surface area is there.
Hereinafter, each component used for the composition of this invention is demonstrated.

<Diene rubber>
The diene rubber used in the composition of the present invention is not particularly limited. Specifically, for example, natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene copolymer rubber. (SBR), acrylonitrile-butadiene copolymer rubber (NBR), butyl rubber (IIR), halogenated butyl rubber (Br-IIR, Cl-IIR), chloroprene rubber (CR) and the like. These may be used alone or in combination of two or more.
Among these diene rubbers, NR is preferable from the viewpoint of a good balance of damping property, workability, and the like, and BR is preferable from the viewpoint that the temperature dependency of damping property and shear modulus can be reduced.
The average molecular weight, monomer composition molar ratio, halogenation rate, and the like of these diene rubbers are not particularly limited, and can be arbitrarily set depending on the intended use.

  In the rubber composition for highly attenuated laminates of the present invention, the above diene rubbers can 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. For example, NR and BR, IR and BR, and NR, IR and BR are preferable. Among these, NR and BR are more preferable because they are more excellent in this characteristic. These mixing ratios are not particularly limited.

<Carbon black>
The carbon black used in the composition of the present invention has the following characteristics (a) to (c).
(A) the nitrogen adsorption specific surface area is 150 to 300 m ² / g, preferably from ^{175~275m 2 / g, 200~250m 2 /} g is more preferable.
Within this range, a high damping property can be imparted to the composition of the present invention, and the dispersibility is not significantly reduced.
The nitrogen adsorption specific surface area refers to the specific surface area obtained by the nitrogen adsorption method. Usually, the larger this value, the smaller the particle size of the carbon black. Since the composition of the present invention uses carbon black having a relatively small particle size and a nitrogen adsorption specific surface area in the above range, it has a high damping property.
In this specification, the nitrogen adsorption specific surface area is measured according to JIS K6217-2-2001.

(B) DBP absorption amount is not more than 115cm ^3/100 g, preferably ^{95~113cm 3 / 100g, 100~110cm 3 /} 100g and more preferably.
DBP absorption is a measure of the ability of carbon black to absorb liquid (DBP), and the smaller this value, the smaller the structure of carbon black.
The present inventor has found that when carbon black having a structure having a DBP absorption amount in the above range is small, a decrease in shear modulus due to repeated shearing can be suppressed. However, when carbon black having a small structure is used, there is a problem that the desired elastic properties cannot be obtained due to a decrease in shear modulus. Therefore, by using carbon black having a DBP absorption amount in the above range, a decrease in shear modulus is suppressed to some extent, and a desired shear modulus can be obtained by satisfying the following property (C).
In this specification, the DBP absorption is measured according to JIS K6217-4-2001.

(C) the difference between the nitrogen adsorption specific surface area and CTAB adsorption specific surface area was 5~34m ² / g, preferably from ^{20~32m 2 / g, 25~32m 2 /} g is more preferable.
The difference between the nitrogen adsorption specific surface area and the CTAB adsorption specific surface area represents the degree of unevenness on the surface of the carbon black. Since the composition of the present invention uses carbon black having a relatively small unevenness between the nitrogen adsorption specific surface area and the CTAB adsorption specific surface area in the above range, the interaction between the carbon black and the diene rubber is increased, It is considered that the dispersibility of carbon black is increased. Therefore, it is possible to suppress a decrease in shear modulus accompanying a decrease in dispersibility of carbon black, and a desired shear modulus can be obtained.
The difference between the nitrogen adsorption specific surface area and the CTAB adsorption specific surface area is a value obtained by subtracting the CTAB adsorption specific surface area from the nitrogen adsorption specific surface area, ie, (nitrogen adsorption specific surface area) − (CTAB adsorption specific surface area).
In this specification, the CTAB adsorption specific surface area is measured according to JIS K6217-3-2001.

  The carbon black content is 50 to 90 parts by mass with respect to 100 parts by mass of the diene rubber. When the content is within this range, the effect of the carbon black can be sufficiently exhibited, and as a result of good dispersibility, the resulting composition can exhibit the effect of the present invention. From the point which is excellent by these characteristics, 55-75 mass parts is preferable with respect to 100 mass parts of said diene rubbers, and, as for content of the said carbon black, 60-73 mass parts is more preferable.

<Petroleum resin>
The composition of the present invention preferably further contains a petroleum resin.
Examples of the petroleum resin include C5 aliphatic unsaturated hydrocarbon polymer, C9 aromatic unsaturated hydrocarbon polymer, C5 aliphatic unsaturated hydrocarbon and C9 aromatic unsaturated polymer. And a copolymer with a saturated hydrocarbon.
The rubber composition for a high damping laminate containing the above petroleum resin is particularly excellent in the damping improvement effect, and when used in combination with an aggregate of quartz and kaolinite, which will be described later, stable high damping and excellent shear modulus. Can be demonstrated.

Examples of the C5 aliphatic unsaturated hydrocarbon include 1-pentene, 2-pentene, 2-methyl-1-butene, and 3-methyl-1 contained in a C5 fraction obtained by thermal decomposition of naphtha. -Olefin hydrocarbons such as butene and 2-methyl-2-butene; such as 2-methyl-1,3-butadiene, 1,2-pentadiene, 1,3-pentadiene, 3-methyl-1,2-butadiene, etc. A diolefin type hydrocarbon is mentioned.
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.

Examples of the C9 aromatic unsaturated hydrocarbon include α-methylstyrene, o-vinyltoluene, m-vinyltoluene, p-vinyltoluene and the like contained in the C9 fraction obtained by thermal decomposition of naphtha. A vinyl substituted aromatic hydrocarbon is mentioned.
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-mentioned petroleum resin has a molecular weight and a double bond reactivity affecting 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.

  Content of the said petroleum resin is 5-45 mass parts with respect to 100 mass parts of said diene rubbers, and it is preferable that it is 10-45 mass parts. When the amount of the petroleum resin is within this range, the laminate using this rubber composition maintains a high damping property, has a low temperature dependency, and does not deteriorate the stability against long-term repeated shear deformation. Excellent characteristics can be obtained.

  The mass ratio (inorganic filler / petroleum resin) between the inorganic filler and the petroleum resin described later is preferably 1 / 0.2 to 1 / 3.5 in the range of the mass part. In such a range, it is excellent in high damping property and stability against repeated shear deformation. From the point which is excellent by these characteristics, it is more preferable that it is 1 / 1-1 / 3.0, and it is still more preferable that it is 1 / 1-1 / 2.5.

<Silica>
It is one of the preferred embodiments that the composition of the present invention further contains silica.
A conventionally well-known thing can be used for the silica used for this invention. Examples thereof include fumed silica, calcined silica, precipitated silica, pulverized silica, and fused silica. These may be used alone or in combination of two or more.
Silica preferably has an average aggregate particle diameter of 5 to 50 μm, more preferably 5 to 30 μm.

  As for the quantity of a silica, 5-35 mass parts is preferable with respect to 100 mass parts of diene rubbers, and 10-30 mass parts is more preferable. In such a range, the damping property and the shear modulus are excellent.

<Inorganic filler>
It is one of the preferred embodiments that the composition of the present invention further contains an inorganic filler.
The inorganic filler does not include the above-described carbon black and silica.
Examples of the inorganic filler used include soft clays such as T-clay, kaolin clay, wax stone clay, sericite clay, and calcined clay; diatomaceous earth; heavy calcium carbonate, magnesium carbonate, aluminum hydroxide, sulfuric acid Examples include aggregates of barium, talc, quartz and kaolinite. Among these, T-clay, kaolin clay, and an aggregate of quartz and kaolinite are preferable from the viewpoint that damping properties and stability of physical properties against repeated shear deformation can be kept particularly high.

A conventionally well-known thing can be used for the aggregate of the said quartz and kaolinite. Especially, it is preferable that it is a natural coupling | bonding material of block quartz and plate-shaped kaolinite. Specifically, as a commercially available product, for example, siritin (Siritin Z86, Siritin V85, Siritin N82, Siritin 85, Siritin N87 (all manufactured by Hoffman Mineral Co., Ltd.)) is preferable. In addition, what has the same structure manufactured artificially can also be used.
When the composition of the present invention contains an aggregate of the above quartz and kaolinite, it is particularly excellent in the effect of improving the stability of the damping property and shear modulus, and when used in combination with the above petroleum resin, the damping property and the shear elasticity. The rate can be demonstrated more stably.

  The mass ratio (quartz / kaolinite) of quartz and kaolinite constituting the aggregate of quartz and kaolinite is not particularly limited. Even if the laminate using the rubber composition containing the agglomerates is repeatedly subjected to shear deformation, it is possible to stably exhibit higher damping and superior shear modulus, and thus the mass ratio of quartz and kaolinite. Is preferably 12/1 to 1/1, and more preferably 9/1 to 2/1 from the viewpoint of excellent characteristics.

  The aggregate of quartz and kaolinite can contain, for example, iron oxide, phosphorus component, and sulfur component in addition to quartz and kaolinite. Such an aggregate may be used independently and may use 2 or more types together.

  The amount of the inorganic filler is preferably 5 to 55 parts by mass, more preferably 10 to 50 parts by mass, and still more preferably 15 to 40 parts by mass with respect to 100 parts by mass of the diene rubber. When the amount of the inorganic filler is within such a range, the composition of the present invention can stabilize the damping property and shear elastic modulus against long-term repeated shear deformation while maintaining high damping property. .

  Moreover, it is preferable that it is 20-75 mass parts with respect to 100 mass parts of said diene rubbers, and, as for the total amount of a silica and an inorganic filler, 30-65 mass parts is more preferable. When the total amount of silica and inorganic filler is in such a range, the damping property is higher, and the damping property and the shear elastic modulus against long-term repeated shear deformation are more stable. A thing is obtained.

  The mass ratio of the silica to the inorganic filler is preferably 1/1 to 1 / 2.5, more preferably 1/1 to 1 / 2.0. When the mass ratio of silica and inorganic filler is within this range, good processability can be obtained.

<Additives>
The composition of the present invention can contain other additives as necessary within a range not impairing the object of the present invention.
Examples of the additive include vulcanizing agents such as sulfur and zinc oxide; organic sulfur-containing compounds such as TMTD; organic peroxides such as dicumyl peroxide; N-cyclohexyl-2-benzothiazole sulfenamide (CBS) ), Sulfenamides such as mercaptobenzothiazole, thiurams such as tetramethylthiuram monosulfide, vulcanization accelerators such as stearic acid; ketone / amine condensates such as TMDQ, amines such as DNPD, styrene Anti-aging agents such as monophenols such as fluorinated phenols; Plasticizers such as monoesters such as phthalic acid derivatives such as DBP and DOP and sebacic acid derivatives such as DBS; Softeners such as paraffinic oils (process oils etc.) Vulcanization aids; flame retardants; weathering agents; heat-resistant agents and the like.

  The production method of the composition of the present invention is not particularly limited. For example, an unvulcanized rubber composition containing the above-described components can be appropriately molded and prepared by kneading using a known method and apparatus. .

  As described above, the rubber composition for high damping bearings of the present invention has high damping properties, excellent shear modulus, little increase in shear modulus against long-term repeated shear deformation, and exhibits stable characteristics over a long period of time. can do.

Hereinafter, the high-damping bearing body of the present invention will be described in detail.
The high-damping bearing body of the present invention is a high-damping bearing body obtained by alternately laminating the composition of the present invention and a steel plate, and is a structure used for bridge bearings, foundation isolation of buildings, and the like. .
FIG. 1 shows a schematic cross-sectional view of a high-damping bearing body 1 representing an example of the high-damping bearing body of the present invention. In FIG. 1, 1 is a high damping bearing (base-isolated laminate), 2 is a hard plate, and 3 is a rubber composition for high damping bearings of the present invention.
The high damping bearing body 1 of the present invention is configured by alternately laminating the rubber composition 3 for high damping bearing of the present invention and a hard plate 2 made of, for example, a general structural steel plate, a cold rolled steel plate, or the like. In addition, the support body 1 may be configured by providing an adhesive layer between the rubber composition 3 for high damping support of the present invention and the hard plate 2, or directly vulcanized without providing an adhesive layer. May be configured.
The high-damping bearing body 1 of the present invention is formed by alternately laminating the rubber composition 3 for high-damping bearing of the present invention and the hard plate 2, but the rubber composition 3 for high-damping bearing 2 has two or more layers. It is good also as a structure which laminated | stacked.

  The number of layers of the high damping bearing rubber composition 3 of the present invention and the hard plate 2 of the high damping bearing body 1 of the present invention is shown in FIG. Although the example of a total of 13 layers of 7 layers for the plate 2 is shown, it is not particularly limited to this, and it can be arbitrarily set according to the intended use, required characteristics, and the like. Further, the size, the overall thickness, the thickness of the rubber composition 1 layer, the thickness of the hard plate 1 layer, etc. of the high-damping support body 1 of the present invention depend on the intended use and required characteristics. Can be set arbitrarily.

  In order to manufacture the high-damping support 1, the rubber composition 3 for high-damping support of the present invention is molded and vulcanized to obtain a sheet-like rubber composition, and then a layer containing an adhesive is provided. The rubber composition 3 may be laminated alternately with the hard plate 2, or the unvulcanized rubber composition 3 for high damping support of the present invention is formed into a sheet shape, laminated with the hard plate 2 alternately, and then heated. The vulcanization and adhesion may be performed simultaneously.

  In the high damping bearing of the present invention, the lower limit of the shear modulus (Geq) obtained by the method described later is preferably 0.85 or more, more preferably 0.86 or more, and the upper limit is 1.10. It is preferable that:

In the high damping bearing of the present invention, the equivalent damping constant (Heq) and shear modulus (Geq) required for each product are satisfied, and the Heq change ratio and Geq change ratio required by the method described later are as follows. A range is preferred.
The lower limit of the Heq change ratio in the highly attenuated bearing body of the present invention is preferably 0.82 or more from the viewpoint that the decrease in Heq is small with respect to repeated shear deformation (the decrease in attenuation is small), and this characteristic is excellent. In this respect, 0.84 or more is more preferable, and 0.86 or more is still more preferable.
In addition, the upper limit of the Geq change ratio in the high damping bearing of the present invention is preferably 1.15 or less from the viewpoint that the increase in Geq is small (the increase in shear rigidity is small). 10 or less is more preferable, and 1.05 or less is still more preferable. The lower limit of the Geq change ratio is preferably 0.90 or more.

  The Heq and Geq of the high damping bearing of the present invention are measured by the following lap shear test. As a sample for a lap shear type shear test, the unvulcanized rubber composition of the rubber composition for high damping bearing of the present invention was rolled to a size of 25 mm width × 25 mm length × 5 mm thickness, and the surface was sandblasted. A steel plate (width 25 mm × length 100 mm × thickness 20 mm) coated with a metal adhesive was placed (laminated) as shown in the side view of the sample 4 for lap shear type shear test in FIG. Uses press-vulcanized for 120 minutes. In FIG. 2, the unvulcanized rubber composition rolled to a size of width 25 mm × length 25 mm × thickness 5 mm is simply represented as a rolled unvulcanized rubber composition 5 and the surface is sandblasted. A steel plate (width 25 mm × length 100 mm × thickness 20 mm) coated with a metal adhesive is simply represented as a steel plate 6.

A lap shear test is performed under the following conditions using a vibrator (manufactured by Saginamiya), an input signal oscillator, and an output signal processor.
Using the produced lap shear type shear test sample, the average shear characteristic value of each time when 175% strain was applied 10 times under a deformation frequency of 0.5 Hz by a biaxial shear tester at a measurement temperature of 23 ° C. (N = 10) (Geq ¹ , Heq ¹ ) is obtained. Geq ¹ and Heq ¹ are calculated according to the following formulas (1) and (2) from the hysteresis loop obtained by the lap shear type shear test.
Further, using this support body, after adding 70% strain 5000 times under the same conditions, average shear characteristic values (Geq ² , Heq ² ) are obtained again under the same conditions as the above shear characteristic values.

Next, determine the divided by GEQ variation ratio Heq variation ratio obtained by dividing the Heq ² in Heq ¹ and a GEQ ² at GEQ ^1. Based on the Heq change ratio and the Geq change ratio, changes in physical properties when the support body is repeatedly subjected to shear deformation can be evaluated.

  FIG. 3 is a graph showing an example of a hysteresis curve of a support body. A shear strain is periodically applied to the support body from one direction, and the stress of the support body caused by the shear strain is distorted on the horizontal axis. (%), The vertical axis represents stress. The equivalent damping constant (Heq) and shear modulus (Geq) of the support are expressed by the following formulas (1) and (2), respectively.

In formula (1), ΔW is the area of the hysteresis loop (shaded portion in the figure).
In the formula (2), Keq is represented by the following formula (3), H represents the total thickness of the rubber layer laminated in the support body, and A represents the cross-sectional area of the rubber layer.

  The use, application conditions, etc. of the high-damping bearing body (base-isolated laminate) of the present invention are not particularly limited as long as it is used as a vibration energy absorbing device. It is preferably used as an energy absorbing device, for example, a vibration energy absorbing device such as various types of seismic isolation, vibration isolation or vibration isolation (more specifically, for example, support for road bridges, bridges, building foundations, etc. It is suitably used for seismic isolation, detached base isolation applications, etc.

Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these.
<Examples 1-2 and Comparative Examples 1-4>
1. Preparation of unvulcanized rubber composition and measurement of carbon black dispersion rate Each component was blended with the composition shown in Table 1 below (unit: parts by mass), and kneaded for 5 minutes with a B-type Banbury mixer, and unvulcanized. A rubber composition was prepared, and the dispersion ratio of carbon black at that time was measured according to ASTM D-2663.
The results are shown in Table 1.

2. Preparation of sample for lap shear type shear test The obtained unvulcanized rubber composition was rolled into a size of 25 mm width × 25 mm length × 5 mm thickness. The unvulcanized rubber composition (5 in FIG. 2) and a steel plate (25 mm wide × 100 mm long × 20 mm thick, 6 in FIG. 2) coated with a metal adhesive by sandblasting the surface After placing (lamination) as shown in the side view of the sample 4 for lap shear type shear test 2 of 2, a sample for lap shear type shear test was produced by press vulcanization at 130 ° C. for 120 minutes.

3. Lap shear test The lap shear test was performed using a vibrator (manufactured by Saginomiya), an input signal oscillator, and an output signal processor. As the sample, the above lap shear type shear test sample was used (the number of samples used in each example was 10). The sample was subjected to a lap shear shear test by applying 175% strain 10 times at a deformation frequency of 0.5 Hz with a biaxial shear tester at a measurement temperature of 23 ° C. Using Xmax and Qmax indicated by the hysteresis loop obtained by the lap shear shear test, average shear characteristic values (Heq ¹ , Geq ¹ ) were determined according to the formulas (1) and (2).
The case where Heq ¹ is 0.15 or more is “◯”, and the case where it is less than 0.15 is “×”.
In addition, the case where Geq ¹ is 0.85 or more is “◯”, and the case where it is less than 0.85 is “×”.

Subsequently, using the sample, a lap shear shear test was performed again with a shear tester similar to the above, with a deformation frequency of 0.5 Hz, a measurement temperature of 23 ° C., and 70% strain applied 5000 times. Similarly to the above, average shear characteristic values (Heq ² , Geq ² ) were obtained.

4). Calculation and Evaluation Results of Geq Change Ratio and Heq Change Ratio Geq ² was divided by Geq ¹ to obtain a Geq change ratio.
As the evaluation result of the Geq change ratio, the value of Geq ² / Geq ¹ is 0.95 or more and 1.05 or less is “◯”, the case where it is more than 1.05 and 1.15 or less is “Δ”, 1 The case of more than 15 was set as “x”.
Further, Heq ² was divided by Heq ¹ to obtain a Heq change ratio.
As an evaluation result of the Heq change ratio, the case where the value of Heq ² / Heq ¹ is 0.82 or more and 1.18 or less is “◯”, and the case where it is less than 0.82 is “X”.
The results are shown in Table 1.

Each component in Table 1 is as follows.
・ Natural rubber: STR20
・ Butadiene rubber: Nipol BR1220, manufactured by Nippon Zeon Co., Ltd. ・ Carbon black 1: Niteron # 410, manufactured by Nisshin Carbon Co. ・ Carbon black 2: Test carbon 1, manufactured by Nisshin Carbon Co. ・ Carbon black 3: Test carbon 2, new Nikka Carbon Co., Ltd., Carbon Black 4: HD-6, Mitsubishi Chemical Co., Ltd., Carbon Black 5: Test Carbon 3, Shin Nikka Carbon Co., Ltd., Carbon Black 6: Test Carbon 4, Shin Nikka Carbon Co., Ltd., oxidation Zinc: 3 types of zinc oxide, manufactured by Shodo Chemical Co., Ltd., stearic acid: beads stearic acid YR, manufactured by Nippon Oil & Fats Co., Ltd., anti-aging agent: 6C, manufactured by Seiko Chemical Co., Ltd. Resin: High Resin # 120, manufactured by Toho Chemical Co., Ltd., softening point 120 ° C
Aroma oil: Diana Process AH-20, manufactured by Idemitsu Kosan Co., Ltd. Sulfur: powder sulfur, manufactured by Hosoi Chemical Co., Ltd. Vulcanization accelerator: Noxeller CZ, manufactured by Ouchi Shinsei Chemical Co., Ltd.

DBP absorption amount, nitrogen adsorption specific surface area (N2SA), CTAB adsorption specific surface area (CTAB), and difference between nitrogen adsorption specific surface area and CTAB adsorption specific surface area in Table 1 (N2SA) -CTAB) is shown in Table 2 below.
The DBP absorption was measured according to JIS K6217-4-2001, the nitrogen adsorption specific surface area was measured according to JIS K6217-2-2001, and the CTAB adsorption specific surface area was measured according to JIS K6217-3-2001.

As is clear from the results shown in Table 1, the samples (Examples 1 and 2) using carbon black having colloidal characteristics shown in Table 2 within the scope of the present invention are compared to Comparative Examples 1 to 4. The carbon dispersion rate was high, the shear modulus (Geq ¹ ) was excellent, and the Geq change rate was small. Furthermore, the equivalent damping constant (Heq) was also excellent.

FIG. 1 is a schematic cross-sectional view of a high-damping bearing body 1 representing an example of the high-damping bearing body of the present invention. FIG. 2 is a side view of a sample for a lap shear type shear test. FIG. 3 is a graph showing an example of the hysteresis curve of the support body.

Explanation of symbols

1 High damping bearing (base-isolated laminate)
2 Hard plate 3 Rubber composition for high damping bearing of the present invention 4 Sample for lap shear type shear test 5 Rolled unvulcanized rubber composition 6 Steel plate

Claims (3)

100 parts by weight of diene rubber,
Nitrogen adsorption specific surface area of 200 to 300 m ² / g and, DBP absorption of 115cm ^3/100 g or less, and carbon black 50 the difference between the nitrogen adsorption specific surface area and CTAB adsorption specific surface area of 5~34m ² / g ~ 90 parts by mass;
Containing petroleum resin ,
The rubber composition for high damping bearings , wherein the content of the petroleum resin is 5 to 45 parts by mass with respect to 100 parts by mass of the diene rubber . The rubber composition for a high damping bearing according to claim 1, wherein the softening point of the petroleum resin is 120 ° C or higher. A high damping support obtained by alternately laminating the rubber composition for high damping support according to claim 1 or 2 and a hard plate.

Images