JP6136106B2 - Rubber composition for high damping rubber bearing and high damping rubber bearing - Google Patents

Description

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

In recent years, seismic isolation devices, seismic isolation devices, seismic isolation devices and the like are rapidly spreading as vibration energy absorbing devices. In such an apparatus, a rubber composition having vibration energy damping performance is used. The applicant of the present application has so far proposed a rubber composition for a high-damping laminate and a high-damping laminate as disclosed in Patent Document 1, etc.
There is a demand for high-damping rubber bearings to be used even in cold regions, but resin-based damping imparting agents such as petroleum resin included in high-damping rubber bearings improve damping properties, but the temperature dependence of shear modulus. Therefore, there is a problem that the resin-rich compounding material cannot satisfy the required performance in a cold region (Comparative Example 1 of this application).
On the other hand, by adding a large amount of carbon black and silica to the high-damping rubber bearing, it is possible to improve the damping property without deteriorating the temperature dependence of the high-damping rubber bearing, but the material viscosity becomes high, It is difficult to actually deteriorate the workability and actually produce it in the factory (Comparative Example 2 of the present application).
Regarding such problems, with the aim of improving the temperature dependence of the elastic properties while ensuring the processability of the rubber composition, and further realizing higher damping properties, a rigid hard plate and A base-isolated rubber laminate composed of alternately laminated rubber layers, wherein the rubber layer uses a rubber material mainly composed of butadiene rubber, with respect to 100 parts by weight of the rubber material, 90 to 120 parts by weight of carbon black having a nitrogen adsorption specific surface area of 150 to 230 m ² / g and an inter-aggregate distance of 7 to 12 nm, and 10 to 10 of at least one of asphalts, tars and pitches There has been proposed a seismic isolation rubber laminate characterized in that it is formed using a rubber composition obtained by compounding 100 parts by weight with each other (Patent Document 2).

JP 2011-132363 A JP 2006-335052 A

However, the inventor of the present application has found that there is room for improvement in the temperature dependence of the shear modulus of the composition containing carbon black and asphalts, etc., relative to the rubber material mainly composed of butadiene rubber. (Application Comparative Example 4).
Accordingly, an object of the present invention is to provide a rubber composition for a high-damping rubber bearing and a high-damping rubber bearing using the same, which can improve the temperature dependence of the shear modulus without reducing the damping performance.

  As a result of intensive studies to solve the above problems, the present inventor has found that the diene rubber component containing polybutadiene containing a syndiotactic polybutadiene resin is at least one selected from the group consisting of 100 parts by mass, SBS, SIS and SEBS. A rubber composition containing 3 to 50 parts by mass of a polymer-modified asphalt containing a kind of thermoplastic elastomer and 5 to 30 parts by mass of a petroleum resin having a softening point of 100 ° C. or higher, without reducing the damping performance, The present invention was completed by finding that a laminate capable of improving the temperature dependence of the shear modulus was obtained.

That is, this invention provides the following 1-6.
1. 100 parts by mass of a diene rubber component containing polybutadiene containing a syndiotactic polybutadiene resin, and 3 to 50 parts by mass of a polymer-modified asphalt containing at least one thermoplastic elastomer selected from the group consisting of SBS, SIS and SEBS And the rubber composition for high damping rubber supports which mix | blends 5-30 mass parts of petroleum resins with a softening point of 100 degreeC or more.
2. Furthermore, the nitrogen specific surface area is 200 to 230 m ² / g, and carbon black having a DBP oil absorption of 100 to 130 ml / g is blended in an amount of 50 to 90 parts by mass and silica 1 to 50 parts by mass. Rubber composition for high damping rubber bearings.
3. The softening point of the polymer-modified asphalt is 56 ° C. or more, and the content of the thermoplastic elastomer is 5 to 20% by mass in the polymer-modified asphalt. Rubber composition.
4). The rubber composition for a high damping rubber bearing according to any one of the above 1 to 3, wherein the total amount of the polymer-modified asphalt and the petroleum resin is 35 parts by mass or less with respect to 100 parts by mass of the diene rubber component. object.
5. The rubber composition for high-damping rubber bearing according to any one of 1 to 4 above, wherein a mass ratio of the polymer-modified asphalt to the petroleum resin (polymer-modified asphalt / petroleum resin) is 8/1 to 1/1. object.
6). A high damping rubber bearing obtained by alternately laminating the rubber composition for high damping rubber bearing according to any one of the above 1 to 5 and a hard plate.

  The composition for high damping rubber bearings of the present invention and the high damping rubber bearing of the present invention can improve the temperature dependence of the shear modulus without lowering the damping performance.

FIG. 1 is a schematic cross-sectional view schematically showing an example of the high-damping rubber bearing of the present invention. FIG. 2 is a schematic side view of a sample for a lap shear type shear test.

The present invention is described in detail below.
The rubber composition for high damping rubber support of the present invention (rubber composition of the present invention) is a diene rubber component containing polybutadiene containing a syndiotactic polybutadiene resin from a group consisting of 100 parts by mass, SBS, SIS and SEBS. A rubber composition for high damping rubber bearings, comprising 3 to 50 parts by weight of polymer-modified asphalt containing at least one selected thermoplastic elastomer and 5 to 30 parts by weight of a petroleum resin having a softening point of 100 ° C. or higher. is there.
The rubber composition of the present invention can greatly reduce the blending amount of petroleum resin by blending the polymer-modified asphalt and improve the temperature dependence of the shear modulus without reducing the damping performance. Therefore, it is suitable for a rubber composition as a high-damping rubber bearing (for example, a rubber bearing for a bridge) that undergoes repeated deformation over many years.

<Rubber>
The diene rubber component contained in the rubber composition of the present invention is not particularly limited except that it contains polybutadiene containing a syndiotactic polybutadiene resin.
In the present invention, the diene rubber component contains polybutadiene (BR) containing a syndiotactic polybutadiene resin for the purpose of reducing the temperature dependence of the shear modulus without reducing the damping property.
The syndiotactic polybutadiene resin refers to a syndiotactic polybutadiene resin obtained by 1,2-polymerizing butadiene. The monomer used can be butadiene only.
One preferred embodiment of the syndiotactic polybutadiene resin is that it is crystalline. The crystallinity of the syndiotactic polybutadiene resin is preferably 90% or more, and more preferably 95% or more. The crystallinity of the syndiotactic polybutadiene resin can be approximately 100%. The syndiotactic polybutadiene resin is preferably not elastomeric from the viewpoint of excellent reinforcement and damping properties.

In the present invention, the polybutadiene may be a butadiene homopolymer.
The polybutadiene containing a syndiotactic polybutadiene resin is, for example, a cis-1,4-polybutadiene containing a cis 1,4-bond (cis bond) in addition to the syndiotactic polybutadiene resin (this is simply referred to as “containing a cis bond”). May be referred to as “polybutadiene”. The amount of cis-1,4-bond contained in cis-1,4-polybutadiene can be 90% or more. In addition to cis-1,4-bond, cis-1,4-polybutadiene is, for example, trans 1,4-bond (the amount can be 3% or less in cis-1,4-polybutadiene), vinyl. Bonds (the amount can be 3% or less in cis-1,4-polybutadiene).
As a polybutadiene containing a syndiotactic polybutadiene resin, for example, a composite or polymer alloy (so-called vinyl-cis butadiene rubber: obtained from cis-1,4-polybutadiene and syndiotactic-1,2-polybutadiene: VCR); polybutadiene containing cis bonds (for example, 98% or more having cis bonds) is used as a matrix polymer, and syndiotactic polybutadiene resin (for example, having a crystallinity of about 100%) is microscopically contained in the matrix polymer. Dispersed ones are mentioned.
The amount of syndiotactic-1,2-polybutadiene is 3 to 20% by mass in the total amount of polybutadiene, and the amount of polybutadiene other than syndiotactic-1,2-polybutadiene (for example, polybutadiene containing a cis bond) is 97. It is preferable that it is -80 mass%. The same applies to the amount of syndiotactic-1,2-polybutadiene and the amount of polybutadiene other than syndiotactic-1,2-polybutadiene in the vinyl-cis butadiene rubber.
As a polybutadiene (vinyl-cis butadiene rubber) containing a syndiotactic polybutadiene resin, for example, a commercially available product such as UBEPOL-VCR manufactured by Ube Industries, Ltd. can be used.
Syndiotactic polybutadiene resin or polybutadiene containing syndiotactic polybutadiene resin is not particularly limited in its production.

  Examples of the diene rubber that the diene rubber can contain in addition to polybutadiene include, for example, natural rubber (NR), isoprene rubber (IR), butyl rubber (IIR), halogenated butyl rubber (Br-IIR, Cl-IIR), Diene rubber (excluding butadiene homopolymer and butadiene copolymer), such as chloroprene rubber (CR); styrene-butadiene copolymer rubber (SBR), acrylonitrile-butadiene copolymer rubber (NBR) Examples thereof include butadiene copolymers. The average molecular weight of the rubber, the monomer, the constituent molar ratio of the monomer, the halogenation rate, and the like are not particularly limited, and can be arbitrarily set as necessary. NR is preferable because of a good balance between attenuation and workability.

In the present invention, the diene rubbers can be used alone or in combination of two or more.
As a suitable combination of rubber when using polybutadiene and a diene rubber other than polybutadiene, from the viewpoint of compatibility between rubber components, processability, green strength and vulcanized physical properties, for example, a combination of BR and NR , A combination of BR and IR, a combination of BR, NR and IR.
Of these, the combination of BR and NR is preferred because the temperature dependence of the shear modulus can be further improved without reducing the damping performance. Vinyl-cisbutadiene rubber (VCR) and NR are preferred. The combination of is particularly preferable.

  When using a VCR as the diene rubber (including when used in combination with NR, for example), it is preferable to contain 10% by mass or more of the VCR from the viewpoint of excellent temperature dependence and damping of the shear modulus. 50% by mass or more is more preferable, and 70% by mass or more is more preferable.

<Polymer modified asphalt>
The polymer-modified asphalt contained in the rubber composition of the present invention was obtained by adding asphalt SBS (styrene-butadiene-styrene block copolymer), SIS (styrene-isoprene-styrene block copolymer) and SEBS (hydrogenating, Modified with at least one thermoplastic elastomer selected from the group consisting of polystyrene-block-poly (ethylene-co-butylene) -block-polystyrene), or selected from the group consisting of asphalt and SBS, SIS and SEBS And at least one thermoplastic elastomer mixed beforehand.
By containing the polymer-modified asphalt, the rubber composition of the present invention can greatly reduce the blending amount of petroleum resin, and improve the temperature dependence of the shear modulus without reducing the damping performance. And processability and set resistance can be improved. Further, in the rubber composition of the present invention, the polymer-modified asphalt functions as a plasticizer, makes the rubber composition have good flowability, and has excellent set resistance when uncompressed against rubber. it can. Such excellent set resistance of the polymer-modified asphalt is not found in asphalt (for example, natural asphalt, straight asphalt).

The asphalt used in the production of the polymer-modified asphalt is not particularly limited as long as it contains asphaltenes. For example, a conventionally well-known thing is mentioned. Specific examples include petroleum asphalt such as natural asphalt, straight asphalt, blown asphalt, and cutback asphalt. Among them, straight asphalt is preferable from the viewpoint that the temperature dependence of the shear modulus can be further improved without reducing the damping performance and the workability is excellent.
The thermoplastic elastomer used in the production of the polymer-modified asphalt is at least one selected from the group consisting of SBS, SIS and SEBS. The thermoplastic elastomer is preferably SIS or SBS from the viewpoint that the temperature dependence of the shear modulus can be further improved without deteriorating the damping performance, and the processability and set resistance are excellent.
From the viewpoint that the content of the thermoplastic elastomer in the polymer-modified asphalt can further improve the temperature dependence of the shear modulus without lowering the damping performance, and is excellent in workability and set resistance. It is preferably -20% by mass, more preferably 5-15% by mass.

The polymer-modified asphalt is not particularly limited for its production. For example, a conventionally well-known thing is mentioned.
In the present invention, the softening point of the polymer-modified asphalt is preferably 56 ° C. or higher from the viewpoint of excellent balance between damping properties and low temperature characteristics, and more preferably 56 ° C. to 100 ° C. for the same reason. .
The polymer-modified asphalts can be used alone or in combination of two or more.
In the present invention, the amount of the polymer-modified asphalt can improve the temperature dependence of the shear elastic modulus without reducing the damping performance, and from the viewpoint of excellent workability and set resistance, the diene rubber 100 It is 3-50 mass parts with respect to a mass part, For the same reason, it is preferable that it is 5-40 mass parts, and it is more preferable that it is 10-35 mass parts.

<Petroleum resin>
The rubber composition of the present invention contains a petroleum resin from the viewpoint of excellent scorch resistance without reducing the damping performance. The petroleum resin contained in the rubber composition of the present invention is not particularly limited. For example, a conventionally well-known thing is mentioned. Specifically, for example, a polymer of C5 aliphatic unsaturated hydrocarbon, a polymer of C9 aromatic unsaturated hydrocarbon, a C5 aliphatic unsaturated hydrocarbon and a C9 aromatic unsaturated Examples thereof include a copolymer with a 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.

In the present invention, the softening point of petroleum resin (JIS K2207) can improve the temperature dependence of the shear modulus without reducing the damping performance, has excellent workability and set resistance, and has excellent rubber properties. On the other hand, since the molecular weight and the reactivity of the double bond have an influence, the temperature is 100 ° C. or higher, and 120 to 150 ° C. is preferable from the viewpoint of being excellent for the same reason.
Petroleum resins can be used alone or in combination of two or more.

  The amount of the petroleum resin is 5 to 30 parts by mass with respect to 100 parts by mass of the diene rubber component from the viewpoint of excellent temperature dependence of shear modulus, damping performance and scorch resistance, and for the same reason, It is preferably 5 to 20 parts by mass.

The total amount of polymer-modified asphalt and petroleum resin can improve the temperature dependence of the shear modulus without reducing the damping performance, and is a diene rubber component from the viewpoint of excellent workability and set resistance. The amount is preferably 45 parts by mass or less, more preferably 35 parts by mass or less, and still more preferably 21 to 35 parts by mass with respect to 100 parts by mass.
The mass ratio of polymer-modified asphalt and petroleum resin (polymer-modified asphalt / petroleum resin) can improve the temperature dependence of the shear modulus without reducing the damping performance, processability and set resistance Is preferably 8/1 to 1/1, and more preferably 6/1 to 4/3 parts by mass.

The rubber composition of the present invention preferably further contains carbon black from the viewpoint of excellent mechanical properties and damping properties. Carbon black is not particularly limited.
The nitrogen specific surface area of carbon black is preferably 200 to 230 m ² / g from the viewpoint of excellent balance between damping properties and shear modulus.
The DBP oil absorption amount of carbon black is preferably 100 to 130 ml / g from the viewpoint of excellent balance between workability and attenuation.
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 high damping rubber bearing of the present invention obtained by alternately laminating the rubber composition of the present invention and the hard plate (hereinafter referred to as “the present invention”). It is also possible to maintain a higher attenuation. 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). The CTAB adsorption specific surface area can be measured by the method described in ASTM D3765-80.
Examples of carbon black include SAF, ISAF, and HAF. Of these, SAF is preferable from the viewpoint of excellent attenuation.

  The content of carbon black is preferably 50 to 90 parts by mass, and preferably 60 to 90 parts by mass with respect to 100 parts by mass of the diene rubber component, from the viewpoint of excellent shear modulus and damping properties. More preferred.

<Silica>
The rubber composition of the present invention preferably further contains silica from the viewpoint of excellent damping properties. Silica is contained as a reinforcing material. Silica is not particularly limited. For example, a conventionally well-known thing can be used. Specific examples include fumed silica, calcined silica, precipitated silica, pulverized silica, and fused silica.
Silica preferably has an average agglomerated particle size of 5 to 50 μm, more preferably 5 to 30 μm, from the viewpoint that the temperature dependence of the shear modulus can be further improved without reducing the damping performance. preferable.
Silica can be used alone or in combination of two or more.

  The content of silica is preferably 1 to 50 parts by mass, and 10 to 35 parts by mass with respect to 100 parts by mass of the diene rubber component, from the viewpoint of excellent balance between damping performance and shear modulus. Is more preferable. When the content of silica is within this range, the resulting high-damping rubber bearing of the present invention has high damping properties and good shear modulus.

  The rubber composition of the present invention can contain an additive as necessary within a range not impairing the object of the present invention. Examples of additives include fillers other than silica and carbon black, plasticizers (eg, aroma oil, paraffin wax), processing aids (eg, fatty acid metal salts), vulcanizing agents, vulcanization accelerators, and anti-aging agents. , Softening agents, vulcanization aids, flame retardants, weathering agents, heat resistance agents, retarders (scorch prevention agents) such as N-cyclohexylthio-phthalimide, and the like.

The rubber composition of this invention is not specifically limited about the manufacturing method. For example, the above-described components can be blended to produce an unvulcanized rubber composition.
The use of the rubber composition of the present invention is a high damping rubber bearing. The rubber composition of the present invention can be used as, for example, a building seismic isolation device other than a high damping rubber bearing.

The high damping rubber bearing of the present invention (laminated body of the present invention) will be described below.
The high damping rubber bearing of the present invention is a laminate obtained by alternately laminating the rubber composition for high damping rubber bearing of the present invention and a hard plate. The laminated body of the present invention can be used as a high-damping rubber bearing, for example, a structure used for a bridge bearing or a building base isolation.

The high damping rubber bearing of the present invention will be described below with reference to the accompanying drawings. The high damping rubber bearing of the present invention is not limited to the attached drawings.
FIG. 1 is a schematic cross-sectional view schematically showing an example of the high-damping rubber bearing of the present invention. In FIG. 1, a high damping rubber bearing (base-isolated laminate) 1 of the present invention has a hard plate 2 and a rubber composition 3 for a high damping rubber bearing. (For example, a general structural steel plate, a cold rolled steel plate, etc.) are alternately laminated. As the rubber composition 3 for high damping rubber support, the rubber composition for high damping rubber support of the present invention is used. The high-damping rubber bearing 1 may be configured by providing an adhesive layer between the rubber composition 3 for the high-damping rubber bearing and the hard plate 2, or by directly vulcanizing without providing the adhesive layer. May be.

  In the present invention, the rubber composition 3 for high damping rubber support may have a structure in which two or more layers are laminated. The number of layers of the rubber composition for the high damping rubber bearing and the hard plate which the high damping rubber bearing of the present invention has is not limited to that shown in FIG. 1, and can be arbitrarily set according to the application used, required characteristics, and the like. . Furthermore, the size and overall thickness of the high-damping structure of the present invention, the layer thickness of the rubber composition for supporting the high-damping rubber of the present invention, the thickness of the hard plate, etc. are also used and required. It can be set arbitrarily according to the characteristics to be determined.

  In order to produce the laminate of the present invention, the rubber composition for high damping rubber support of the present invention is formed into a sheet and then vulcanized to obtain a sheet-like rubber composition, and then a layer containing an adhesive May be laminated alternately with the hard plate, or the rubber composition for supporting the high damping rubber 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. Then, vulcanization and adhesion may be performed simultaneously.

Since the laminated body of the present invention uses the rubber composition of the present invention, the temperature dependence of the shear modulus can be improved without reducing the damping performance.
The ratio of the GEQ ^{23 ° C.} at GEQ ^{-30 ° C.} and 23 ° C. at minus 30 ° C. measured by lap shear shear test described below ^{(Geq -30 ℃ / Geq 23 ℃} ) has preferably small as the temperature dependence close to 1. Geq- ^{30 ° C} / Geq23 ^{° C} is preferably 1.37 or less, more preferably 1.35 or less, and still more preferably 1.30 or less.

The equivalent damping constant (Heq) and shear modulus (Geq) are measured by a lap shear shear test.
FIG. 2 is a schematic side view of a sample for a lap shear type shear test. In FIG. 2, the code | symbol 4 represents the sample for a lap shear type shear test, the code | symbol 5 represents the rolled unvulcanized rubber composition, and the code | symbol 6 represents a steel plate.
The unvulcanized rubber composition 5 is an unvulcanized rubber composition of the rubber composition for high damping rubber support of the present invention, which has been rolled to a size of 25 mm wide × 25 mm long × 5 mm thick. The steel plate 6 is a steel plate (width 25 mm × length 100 mm × thickness 20 mm) having a surface sandblasted and coated with a metal adhesive.
The sample 4 for lap shear type shear test is obtained by placing (stacking) the unvulcanized rubber composition 5 and the steel plate 6 as shown in FIG. 2 and then press vulcanizing at 130 ° C. for 120 minutes.

The lap shear shear test is performed under the following conditions using a vibrator (manufactured by Saginomiya), an input signal oscillator, and an output signal processor.
Using the sample for lap shear type shear test produced as described above, the shear characteristic value when a 175% strain was applied 11 times at a deformation frequency of 0.5 Hz and a measurement temperature of 23 ° C. by a biaxial shear tester. Measure and obtain an average of shear characteristic values per strain (the same applies hereinafter).
Specifically, using the Xmax (strain maximum value) and Qmax (stress maximum value) indicated by the hysteresis curve obtained in the lap shear type shear test, the equivalent damping constant (Heq) and shear modulus (Geq) are calculated. It calculates according to following formula (1), (2).

In formula (1), ΔW is an area in the hysteresis loop.
In the formula (2), Keq is represented by the following formula (3), H represents the total thickness of the rubber layers laminated during the high damping rubber support, and A represents the cross-sectional area of the rubber layer.

  The high damping rubber bearing can be used as a vibration energy absorber. The specific usage, application conditions, etc. are not particularly limited. Among these, since it has the above-described excellent characteristics, it is preferably used as a vibration energy absorption device for buildings. For example, various vibration energy absorption devices for vibration isolation, vibration isolation, vibration isolation, etc. Is suitably used for, for example, support of road bridges, bridges, building base isolation, and detached base isolation applications).

Hereinafter, the present invention will be described more specifically according to examples. The present invention is not limited to the following examples.
<Production of composition>
Each compound was blended so as to have the composition shown in Table 1 below (unit: parts by mass), and the temperature was adjusted with a B-type Banbury mixer: kneaded for 5 minutes at 60 ° C., and unvulcanized rubber A composition was prepared.

<Evaluation>
Samples are prepared by vulcanizing the unvulcanized rubber composition produced as described above by the following methods, and include general physical properties, processability (Mooney scorch), shear properties (shear elastic modulus, equivalent damping constant), and temperature dependence. The set resistance was evaluated. The results are shown in Table 1.
・ General physical properties (tensile properties)
The unvulcanized rubber composition produced as described above 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 out from this sheet, and a tensile test at a tensile speed of 500 mm / min was conducted according to JIS K6251-2004. M300 (300% modulus, unit: MPa), tensile strength (T _B ) [MPa] and elongation at break (E _B ) [%] were measured at room temperature (23 ° C.).
・ Processability (Mooney coach)
About each obtained unvulcanized rubber composition, according to JIS K6300-1-2001, the Mooney viscosity is continuously measured under the conditions of a preheating time of 1 minute and a test temperature of 125 ° C. in accordance with JIS K6300-1-2001. did. The minimum value of the Mooney viscosity was V _m. Moreover, Mooney viscosity was measured Mooney scorch time (minute) until the 5 points from V _m. The Mooney scorch time is an index of scorch (rubber burn) and is preferably longer.
-Lap shear test The unvulcanized rubber composition produced as described above was rolled into a size of 25 mm wide x 25 mm long x 5 mm thick.
An unvulcanized rubber composition after rolling (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. 2 was placed (laminated) as shown in the side view of the lap shear type shear test sample 4 in FIG. 2, and then press vulcanized at 130 ° C. for 120 minutes to prepare a lap shear type shear test sample.
A lap shear shear test was performed on the lap shear type shear test sample using a vibrator (manufactured by Saginomiya), an input signal oscillator, and an output signal processor.
Specifically, the shear characteristics when the lap shear type shear test sample is subjected to 11 times of 175% strain at a deformation frequency of 0.5 Hz by a biaxial shear tester at measurement temperatures of 23 ° C. and −30 ° C. The average of the values was obtained.
Using Xmax and Qmax indicated by the hysteresis curve obtained by this lap shear shear test, average shear characteristic values (Geq, Heq) were determined according to the above formulas (1) and (2).

・ Evaluation of temperature dependence Using the above lap shear type shear test sample, the shear characteristic value when a 175% strain was applied 11 times at a deformation frequency of 0.5 Hz by a biaxial shear tester at a measurement temperature of 23 ° C. The average (Geq ^{23 ° C.} , Heq ^{23 ° C.} ) was determined.
Next, in the same manner as when the measurement temperature is room temperature (23 ° C.) except that the measurement temperature is changed to minus 30 ° C., the average shear property value at minus 30 ° C. (Geq- ^{30 ° C.} , Heq- ^{30 ° C.} ) Asked.
Then, the temperature dependency of the shear modulus (GEQ) in Geq ^{-30 ℃} / Geq ^{23 ℃} calculated this -30 ° C. / 23 ° C. The. In Table 1, Geq- ^{30 ° C} / Geq23 ^{° C} was expressed as Geq temperature dependence. The same applies to the calculation and notation of the temperature dependence of the equivalent attenuation constant (Heq).

-Set resistance The unvulcanized rubber composition produced as described above was press vulcanized at 150 ° C for 30 minutes to obtain a vulcanized rubber composition. Using the resulting vulcanized rubber composition, set resistance was measured according to the method described in JIS K 6262. Under the conditions of a heat treatment temperature of 70 ° C. and a compression time of 22 hours during the compression test, the sample is allowed to cool for 30 minutes after the heat treatment is completed, and the thickness of the specimen is measured. Then, assuming that the reduced thickness of the test piece is 100%, the percentage of how much the test piece has returned to the original thickness during 30 minutes of cooling is expressed as a percentage. 100% is evaluated when the original thickness is not restored while being compressed, and 0% when the original thickness is completely restored. This is called compression set in the JIS handbook, but in this specification, it was evaluated as set resistance.

The following were used for each component in Table 1.
NR: Natural rubber, STR20, manufactured by TECK BEE HANG, Ltd. VCR: Vinyl-cis butadiene rubber. Product name UBEPOL-VCR 412. It contains cis 1,4-polybutadiene and highly crystalline syndiotactic-1,2-polybutadiene in a mass ratio of 88:12, and the matrix polymer (cis 1,4-polybutadiene) has a microstructure of 98 mass% cis, trans 1% by mass and 1% by mass of vinyl. The crystallinity of the highly crystalline syndiotactic-1,2-polybutadiene is approximately 100%. Ube Industries, Ltd. ・ C. B: Carbon black, diamond black I, manufactured by Mitsubishi Chemical Corporation, nitrogen specific surface area: 200 m ² / g, DBP oil absorption: 125 ml / g
Silica: Nip seal VN3, manufactured by Tosoh Silica Co., average agglomerated particle size 20 μm
Aroma oil: Trade name A-OMIX, Sankyo Oil Chemical Co., Ltd., plasticizer Petroleum resin 1: High Resin # 140S (softening point 140 ° C, manufactured by Toho Chemical Co., Ltd.), C9 aliphatic unsaturated hydrocarbon compound Combined ・ Processing aid: Fatty acid zinc salt mixture, trade name STRACTOL EF44, manufactured by SCHILL & SEILACHER GMBH & CO. Co. , Manufactured by Tai'an ・ Polymer-modified asphalt 1: Asphalt modified with SBS, amount of thermoplastic elastomer (SBS) in polymer-modified asphalt is 10% by mass or less, softening point 56 of polymer-modified asphalt 1 ° C or higher, trade name Epoch Palt D, manufactured by Nisshinsei Co., Ltd. Thermoplastic elastomer: SBS (styrene-butadiene-styrene copolymer), trade name Asaprene T, manufactured by Asahi Kasei Co., Ltd. -Paraffin wax: Seiko Chemical Co., Ltd.-Retarder: N-Cyclohexylthio-phthalide, trade name retarder CTP, manufactured by Toray Fine Chemical Co., Ltd.・ Vulcanization accelerator CZ: Noxeller CZ Ouchi Shinko Chemical Industry Co., Ltd. Sulfur: powdered sulfur, Hosoi Chemical Industry Co., Ltd.

As is apparent from the results shown in Table 1, Comparative Example 1, which had a large amount of petroleum resin and did not contain polymer-modified asphalt, had poor Geq temperature dependency (-30 ° C / 23 ° C). In Comparative Example 2 containing no petroleum resin or polymer-modified asphalt, ML5 _up was short and processability was low. In Comparative Example 3 in which the polymer-modified asphalt was not blended and the petroleum resin was blended in an amount exceeding 30 parts by mass, the Geq temperature dependency (−30 ° C./23° C.) was poor. In Comparative Example 4, in which straight asphalt was blended instead of polymer-modified asphalt, Geq temperature dependency (-30 ° C / 23 ° C) was 1.38 or more, and there was room for improvement. Comparative Example 5, which is the same as Comparative Example 4 except that more straight asphalt was added than Comparative Example 4, was inferior to Comparative Example 4 in Geq temperature dependence (-30 ° C / 23 ° C). In Comparative Example 6 containing no syndiotactic polybutadiene resin, the damping performance decreased, the Geq temperature dependency (−30 ° C./23° C.) was poor, the ML5 _up was short, and the workability was low.
On the other hand, Examples 1-5 can improve the temperature dependence of a shear elastic modulus, without reducing damping performance. In particular, Examples 2 and 3 in which the total amount of petroleum resin and polymer-modified asphalt is 35 parts by mass or less and the amount of polymer-modified asphalt is 21 parts by mass or more with respect to 100 parts by mass of the diene rubber component The temperature dependence and workability of the shear modulus can be further improved. Examples 1-4 which further mix | blend carbon black and a silica can improve the temperature dependence of a shear elastic modulus more compared with Example 5 which does not mix | blend a silica.

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

Claims (6)

100 parts by mass of a diene rubber component containing polybutadiene containing a syndiotactic polybutadiene resin, and 3 to 50 parts by mass of a polymer-modified asphalt containing at least one thermoplastic elastomer selected from the group consisting of SBS, SIS and SEBS as well as a softening point 100 ° C. or more petroleum resin 5 to 30 parts by mass, the polybutadiene vinyl as emissions - using cis butadiene rubber, the vinyl - 10 content of cis-butadiene rubber of the diene rubber component A rubber composition for high-damping rubber bearings that is at least mass%. Further, carbon black having a nitrogen specific surface area of 200 to 230 m ² / g and a DBP oil absorption of 100 to 130 ml / g is blended with 50 to 90 parts by mass and silica 1 to 50 parts by mass. The rubber composition for high damping rubber support described.   3. The high-damping rubber bearing according to claim 1, wherein a softening point of the polymer-modified asphalt is 56 ° C. or more, and a content of the thermoplastic elastomer is 5 to 20% by mass in the polymer-modified asphalt. Rubber composition.   The rubber for high damping rubber support according to any one of claims 1 to 3, wherein a total amount of the polymer-modified asphalt and the petroleum resin is 35 parts by mass or less with respect to 100 parts by mass of the diene rubber component. Composition.   The high damping rubber bearing rubber according to any one of claims 1 to 4, wherein a mass ratio of the polymer-modified asphalt to the petroleum resin (polymer-modified asphalt / petroleum resin) is 8/1 to 1/1. Composition.   A high-damping rubber bearing obtained by alternately laminating the rubber composition for a high-damping rubber bearing according to any one of claims 1 to 5 and a hard plate.