JP2016074850A - Rubber composition for aseismic base isolation structure and aseismic base isolation structure using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition for aseismic base isolation structure capable of providing an aseismic base isolation structure good in processability and excellent in attenuation characteristic, creep resistance, low temperature property, low migration performance of a plasticizer or the like and the aseismic base isolation using the rubber composition for aseismic base isolation at least partially.SOLUTION: There is provided a rubber composition for aseismic base isolation structure containing 100 pts.mass of a rubber component consisting of at least one kind of synthetic rubber and natural rubber (A) and 0.1 to 100 pts.mass of a polymer of farnesene (B).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a rubber composition for a base isolation structure containing a rubber component and a farnesene polymer, and a base isolation structure using at least a part of the rubber composition for a base isolation structure.

2. Description of the Related Art In recent years, in the construction industry and the like, seismic isolation technology using a seismic isolation structure such as laminated rubber has attracted attention as a technology for protecting buildings and equipment in buildings from earthquake disasters. In general, seismic isolation means vibration isolation against seismic motion. Specifically, a building is supported by a seismic isolation structure such as laminated rubber to lengthen the period of vibration of the building (natural period), and the building response due to the earthquake The method of reducing is taken.
As the rubber constituting the seismic isolation structure, for the purpose of improving the mechanical strength and creep resistance characteristics of the seismic isolation structure, carbon rubber, silica, etc. are used for rubber components such as natural rubber and styrene butadiene rubber. A rubber obtained from a rubber composition containing a filler is generally used. In rubber compositions containing such fillers, plasticizers such as process oil are used for the purpose of improving processability and fluidity because the viscosity at the time of kneading, rolling and extrusion of the rubber composition increases. ing. Since the plasticizer in this case can soften the rubber after molding, it also has a function as a rubber softener.

However, even if rubber obtained from a rubber composition containing a plasticizer has physical properties such as moderate flexibility and damping characteristics at the time of manufacture, the performance of the rubber will change due to long-term use. There's a problem. This occurs when a plasticizer or the like moves from the inside of the rubber to the outside.
As a method for suppressing such a change in rubber performance due to the migration of the plasticizer, for example, Patent Document 1 describes a high-loss rubber composition for seismic isolation containing a specific phenol resin. Patent Documents 2 and 3 describe a high-damping seismic isolation rubber composition containing a specific polyisoprene rubber.

Japanese Patent No. 2611283 Japanese Patent Laid-Open No. 10-324777 JP 2004-307594 A

Although the rubber composition for seismic isolation structures described in Patent Documents 1 to 3 has damping characteristics required in the seismic isolation structure, low transition performance of the plasticizer, and the like, Since they do not have a sufficiently high level, further improvements are desired.
Further, the rubber obtained from the rubber composition containing a plasticizer has a problem that the creep resistance is greatly deteriorated, and the flexibility at low temperature, that is, the low temperature characteristic is deteriorated. Yes.
The present invention has been made in view of the above circumstances, has good workability, can adjust the hysteresis loss value, has excellent damping characteristics, and has excellent creep resistance, low temperature characteristics, low plasticizer migration performance, and the like. Provided are a rubber composition for a seismic isolation structure capable of obtaining an excellent seismic isolation structure, and a seismic isolation structure using at least a part of the rubber composition for a seismic isolation structure.

  As a result of intensive studies, the present inventors have found that a rubber composition for a base isolation structure using a farnesene polymer is excellent in the above-mentioned performances and is suitable for use in a base isolation structure. completed.

That is, the present invention relates to the following [1] and [2].
[1] Rubber for seismic isolation structure containing 0.1 to 100 parts by mass of farnesene polymer (B) with respect to 100 parts by mass of rubber component (A) comprising at least one of synthetic rubber and natural rubber Composition.
[2] A base-isolated structure using at least a part of the rubber composition for base-isolated structures according to [1].

  According to the present invention, it is possible to obtain a seismic isolation structure having good workability, adjustable hysteresis loss value, excellent damping characteristics, and excellent creep resistance, low temperature characteristics, low plasticizer migration performance, and the like. A rubber composition for a seismic isolation structure that can be provided, and a seismic isolation structure using at least a part of the rubber composition for a seismic isolation structure can be provided.

It is sectional drawing which shows an example of the seismic isolation structure of this invention.

[Rubber composition for seismic isolation structure]
The rubber composition for a seismic isolation structure of the present invention has a farnesene polymer (B) in an amount of 0.1 to 100 masses per 100 mass parts of a rubber component (A) composed of at least one of synthetic rubber and natural rubber. Contains.

<Rubber component (A)>
As the rubber component (A), rubber composed of at least one of synthetic rubber and natural rubber is used.
The rubber component (A) is preferably a solid rubber. The solid rubber is a solid rubber that is not liquid and usually has a Mooney viscosity (ML _{1 + 4} ) at 100 ° C. of 20 to 200.

[Synthetic rubber]
When synthetic rubber is used as the rubber component (A) in the present invention, styrene butadiene rubber (hereinafter also referred to as “SBR”), butadiene rubber, isoprene rubber, butyl rubber, halogenated butyl rubber, ethylene propylene diene rubber, butadiene acrylonitrile copolymer Combined rubber, chloroprene rubber and the like are preferable, and among them, SBR, isoprene rubber and butadiene rubber are more preferable, and SBR is more preferable.

I. SBR (AI)
As SBR (AI), general materials used for seismic isolation structures can be used. Specifically, those having a styrene content of 0.1 to 70% by mass are preferable, and 5 to 50% by mass. %, More preferably 15 to 35% by weight, still more preferably 15 to 25% by weight. Moreover, the thing whose vinyl content is 0.1-60 mass% is preferable, and a 0.1-55 mass% thing is more preferable.
The weight average molecular weight (Mw) of SBR is preferably 100,000 to 2,500,000, more preferably 150,000 to 2,000,000, and still more preferably 200,000 to 1,500,000. When it is in the above range, both workability and mechanical strength can be achieved.
In addition, Mw in this specification is the value measured by the method as described in the Example mentioned later.
The glass transition temperature (Tg) determined by differential thermal analysis of SBR used in the present invention is preferably −95 to 0 ° C., more preferably −95 to −5 ° C. By setting Tg within the above range, it is possible to suppress an increase in viscosity and facilitate handling.

  The SBR that can be used in the present invention is obtained by copolymerizing styrene and butadiene. There is no restriction | limiting in particular about the manufacturing method of SBR, and any of an emulsion polymerization method, a solution polymerization method, a gas phase polymerization method, and a bulk polymerization method can be used, and an emulsion polymerization method and a solution polymerization method are especially preferable.

In the present invention, modified SBR in which a functional group is introduced into SBR may be used. Examples of the functional group include an amino group, an alkoxysilyl group, a hydroxyl group, an epoxy group, and a carboxyl group.
As a method for producing the modified SBR, for example, before adding a polymerization terminator, tin tetrachloride, tetrachlorosilane, dimethyldichlorosilane, dimethyldiethoxysilane, tetramethoxysilane, tetraethoxysilane, which can react with a polymerization active terminal, Coupling agents such as 3-aminopropyltriethoxysilane, tetraglycidyl-1,3-bisaminomethylcyclohexane, 2,4-tolylene diisocyanate, 4,4′-bis (diethylamino) benzophenone, N-vinylpyrrolidone, etc. Or a method of adding other modifiers described in JP2011-132298A.
In this modified SBR, the position of the polymer into which the functional group is introduced may be the polymerization terminal or the side chain of the polymer chain.

II. Isoprene rubber (A-II)
Examples of the isoprene rubber include Ziegler catalysts such as titanium tetrahalide-trialkylaluminum, diethylaluminum chloride-cobalt, trialkylaluminum-boron trifluoride-nickel, and diethylaluminum chloride-nickel; -A commercially available isoprene rubber polymerized using a lanthanoid rare earth metal catalyst such as an organic acid neodymium-Lewis acid type or an organic alkali metal compound can be used. Isoprene rubber polymerized with a Ziegler catalyst is preferred because of its high cis isomer content. Further, isoprene rubber having an ultra-high cis body content obtained using a lanthanoid rare earth metal catalyst may be used.

The vinyl content of the isoprene rubber is preferably 50% by mass or less, more preferably 40% by mass or less, and still more preferably 30% by mass or less. When the vinyl content exceeds 50% by mass, the creep resistance of the resulting rubber tends to deteriorate. The lower limit of the vinyl content is not particularly limited. The glass transition temperature varies depending on the vinyl content, but is preferably −20 ° C. or lower, and more preferably −30 ° C. or lower.
The weight average molecular weight (Mw) of isoprene rubber is preferably 90,000 to 2,000,000, and more preferably 150,000 to 1,500,000. When Mw is in the above range, workability and mechanical strength are good.
A part of the isoprene rubber is a polyfunctional modifier such as tin tetrachloride, silicon tetrachloride, an alkoxysilane having an epoxy group in the molecule, or an amino group-containing alkoxysilane. It may have a branched structure or a polar functional group.

III. Butadiene rubber (A-III)
Examples of the butadiene rubber include Ziegler catalysts such as titanium tetrahalide-trialkylaluminum, diethylaluminum chloride-cobalt, trialkylaluminum-boron trifluoride-nickel, and diethylaluminum chloride-nickel; -Commercially available butadiene rubber polymerized using a lanthanoid rare earth metal catalyst such as an organic acid neodymium-Lewis acid type or an organic alkali metal compound can be used. Butadiene rubber polymerized with a Ziegler catalyst is preferred because of its high cis isomer content. Moreover, you may use the butadiene rubber of the ultra high cis body content obtained using a lanthanoid type rare earth metal catalyst.
The vinyl content of the butadiene rubber is preferably 50% by mass or less, more preferably 40% by mass or less, and still more preferably 30% by mass or less. When the vinyl content exceeds 50% by mass, the creep resistance of the resulting rubber tends to deteriorate. The lower limit of the vinyl content is not particularly limited. The glass transition temperature varies depending on the vinyl content, but is preferably −40 ° C. or lower, and more preferably −50 ° C. or lower.
The weight average molecular weight (Mw) of the butadiene rubber is preferably 90,000 to 2,000,000, more preferably 150,000 to 1,500,000, still more preferably 250,000 to 1,000,000, and 350,000 to 700,000. Even more preferably. When Mw is in the above range, workability and mechanical strength are good.
A part of the butadiene rubber is a polyfunctional type modifier such as tin tetrachloride, silicon tetrachloride, an alkoxysilane having an epoxy group in the molecule, or an amino group-containing alkoxysilane. It may have a branched structure or a polar functional group.

As the rubber component (A), one or more of butyl rubber, halogenated butyl rubber, ethylene propylene diene rubber, butadiene acrylonitrile copolymer rubber, chloroprene rubber and the like can be used. Moreover, these manufacturing methods are not specifically limited, What is marketed can be used.
When two or more kinds of synthetic rubbers are used in combination, the combination can be arbitrarily selected within a range not impairing the effects of the present invention, and the physical properties can be adjusted by the combination.

[Natural rubber]
Examples of the natural rubber used as the rubber component (A) of the present invention include TSR such as SMR, SIR, and STR, natural rubber generally used in seismic isolation structures such as RSS, high-purity natural rubber, and epoxy. And modified natural rubbers such as hydrogenated natural rubber, hydroxylated natural rubber, hydrogenated natural rubber, and grafted natural rubber. Among them, SMR20, STR20, RSS # 3, RSS # 4, and the like are preferable from the viewpoint of little variation in quality and easy availability. These may be used alone or in combination of two or more.

In addition, there is no restriction | limiting in particular in the manufacturing method of the rubber | gum used for the rubber component (A) of this invention, You may use a commercially available thing.
In the present invention, the rubber component (A) and the farnesene polymer (B) described later can be used together to improve processability, and the resulting rubber has creep resistance, damping characteristics, low temperature characteristics, and The low migration performance of the plasticizer can be improved.

  In this invention, 20-99.9 mass% is preferable, as for content of the rubber component (A) in the rubber composition for seismic isolation structures, 25-80 mass% is more preferable, and 30-70 mass% is further. preferable. When the content of the rubber component (A) is within the above range, the damping characteristics are improved.

<Farnesene polymer (B)>
The rubber composition for a base-isolated structure of the present invention contains a farnesene polymer (B) (hereinafter also referred to as “polymer (B)”).
As the polymer (B) in the present invention, at least one of α-farnesene and β-farnesene represented by the following formula (I) can be used as a monomer. Among them, a polymer obtained by polymerizing β-farnesene by the method described later is preferable, and from the viewpoint of ease of production, a homopolymer of β-farnesene and a copolymer containing monomer units derived from β-farnesene. Is more preferable.

In the present specification, the 1,4 bond in the polymer (B) containing a monomer unit derived from β-farnesene refers to a bonding mode represented by the formula (II). The vinyl content in the present specification, among the monomer units derived from the entire β- farnesene is that the content of the binding modes except 1,4 bonds can be measured by a method using ^{1 H-NMR} .

The polymer (B) may be a copolymer containing a monomer unit (b) derived from β-farnesene and a monomer unit (a) derived from a monomer other than β-farnesene. .
When the polymer (B) is a copolymer, examples of the monomer unit (a) derived from a monomer other than β-farnesene include a conjugated diene having 12 or less carbon atoms and an aromatic vinyl compound. The monomer unit to perform can be mentioned.
Examples of the conjugated diene having 12 or less carbon atoms include butadiene, isoprene, 2,3-dimethylbutadiene, 2-phenylbutadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, Examples include 1,3-octadiene, 1,3-cyclohexadiene, 2-methyl-1,3-octadiene, 1,3,7-octatriene, myrcene, chloroprene and the like. Of these, butadiene, isoprene, and myrcene are more preferable. These conjugated dienes may be used alone or in combination of two or more.

  Examples of the aromatic vinyl compound include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-propylstyrene, 4-t-butylstyrene, 4-cyclohexylstyrene, 4- Dodecylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 2,4,6-trimethylstyrene, 2-ethyl-4-benzylstyrene, 4- (phenylbutyl) styrene, 1-vinylnaphthalene, 2- Aromatic vinyl compounds such as vinylnaphthalene, vinylanthracene, N, N-diethyl-4-aminoethylstyrene, vinylpyridine, 4-methoxystyrene, monochlorostyrene, dichlorostyrene, divinylbenzene, and the like can be given. Among these, styrene, α-methylstyrene, and 4-methylstyrene are preferable.

The ratio of the monomer unit (a) to the total of the monomer unit (a) derived from a monomer other than β-farnesene and the monomer unit (b) derived from β-farnesene in the copolymer is as follows: Although it can be arbitrarily adjusted according to the usage mode of the seismic isolation structure, in order to obtain a rubber having a large hysteresis loss value as an index of the damping characteristic, the ratio is preferably 1 to 99% by mass, more Preferably it is 10-80 mass%, More preferably, it is 15-70 mass%, More preferably, it is 15-60 mass%, More preferably, it is just 15-55 mass%. In order to obtain rubber having a particularly large hysteresis loss, it is preferable to use an aromatic vinyl compound as the monomer unit (a) derived from a monomer other than β-farnesene, and the proportion thereof is 30 to 70 mass. % Is preferable, and it is more preferable that it is 40-60 mass%.
Further, in order to obtain rubber having a small hysteresis loss value, it is preferable to use a homopolymer of β-farnesene. Since natural rubber-based laminated rubber requires a high restoring force, a rubber having a small hysteresis loss value is preferable. On the other hand, a high damping rubber-based laminated rubber is required to have high energy absorption performance, and therefore a rubber having a large hysteresis loss value is preferably used. In this specification, natural rubber-based laminated rubber is used to weaken the seismic force by separating the seismic frequency and the natural frequency of the building when horizontal vibrations occur due to an earthquake. It refers to the rubber material for seismic isolation. Natural rubber-based laminated rubber is usually used in combination with a damping damper in order to impart damping properties. On the other hand, the high damping rubber-based laminated rubber in this specification refers to a rubber material for seismic isolation that imparts high damping performance to the rubber itself as well as spring performance.
When the polymer (B) is a copolymer, the bonding mode may be random, block, or other bonding modes.

The weight average molecular weight (Mw) of the polymer (B) is preferably 2,000 to 500,000, more preferably 8,000 to 400,000, still more preferably 8,500 to 300,000, and more preferably 8,500 to 200,000. Further preferred. When the Mw of the polymer (B) is within the above range, the processability of the rubber composition for a base-isolated structure of the present invention is improved. In addition, in this specification, Mw of a polymer (B) is the value calculated | required by the method described in the Example mentioned later.
In the present invention, two types of polymers (B) having different Mw may be used in combination.

  The melt viscosity at 38 ° C. of the polymer (B) is preferably 0.1 to 3,000 Pa · s, more preferably 1 to 3,000 Pa · s, more preferably 1.5 to 2,500 Pa · s, 2,000 Pa · s is more preferable, and 2.5 to 1,500 Pa · s is still more preferable. When the melt viscosity of the polymer (B) is within the above range, kneading of the resulting rubber composition for a base-isolated structure is facilitated and processability is improved. In the present specification, the melt viscosity of the polymer (B) is a value determined by the method described in Examples described later.

  The molecular weight distribution (Mw / Mn) of the polymer (B) is preferably 1.0 to 8.0, more preferably 1.0 to 5.0, and still more preferably 1.0 to 3.0. It is more preferable that Mw / Mn is within the above range, since the dispersion of the viscosity of the obtained polymer (B) is small.

  The glass transition temperature of the polymer (B) varies depending on the vinyl content, farnesene, and the content of monomers other than farnesene as required, but is preferably -90 to 10 ° C, and preferably -90 to 0 ° C. Is more preferable, and −90 to −5 ° C. is still more preferable. Within the above range, it is possible to suppress the viscosity of the resulting rubber from becoming high, and handling becomes easy. The vinyl content of the polymer (B) is preferably 99% by mass or less, and more preferably 90% by mass or less.

  In this invention, content of the polymer (B) with respect to 100 mass parts of rubber components (A) is 0.1-100 mass parts, 0.5-50 mass parts is preferable, and 1-40 mass parts is more preferable. 2 to 35 parts by mass are more preferable. When the content of the polymer (B) is within the above range, workability is improved.

  The polymer (B) can be produced by a bulk polymerization method, an emulsion polymerization method, a method described in International Publication No. 2010/027463, International Publication No. 2010/027464, or the like. Among them, the bulk polymerization method, the emulsion polymerization method or the solution polymerization method is preferable, and the solution polymerization method is more preferable.

(Bulk polymerization method)
A known method can be applied as the bulk polymerization method. For example, it can be carried out by stirring and mixing farnesene and aromatic vinyl compound as raw materials and polymerizing in the absence of a solvent with a radical polymerization initiator.
Examples of the radical polymerization initiator include azo compounds, peroxide compounds, and redox compounds. Particularly, azobisisobutyronitrile, tert-butyl peroxypivalate, di-tert-butyl peroxide, i -Butyryl peroxide, lauroyl peroxide, succinic acid peroxide, dicinnamyl peroxide, di-n-propyl peroxydicarbonate, tert-butylperoxyallyl monocarbonate, benzoyl peroxide, hydrogen peroxide, ammonium persulfate, etc. preferable.
Although superposition | polymerization temperature can be suitably selected according to the kind of radical polymerization initiator to be used, 0-200 degreeC is preferable normally and 0-120 degreeC is more preferable. The polymerization mode may be either continuous polymerization or batch polymerization. The polymerization reaction can be stopped by adding a polymerization terminator.
Examples of the polymerization terminator include amine compounds such as isopropylhydroxylamine, diethylhydroxylamine and hydroxylamine, quinone compounds such as hydroquinone and benzoquinone, sodium nitrite and the like.
Examples of the method for removing the residual monomer from the obtained copolymer include methods such as reprecipitation and heat distillation under reduced pressure.

(Emulsion polymerization method)
As an emulsion polymerization method for obtaining the polymer (B), a known method can be applied. For example, a predetermined amount of farnesene monomer is emulsified and dispersed in the presence of an emulsifier, and emulsion polymerization is performed using a radical polymerization initiator.
As the emulsifier, for example, a long chain fatty acid salt or rosin acid salt having 10 or more carbon atoms is used. Specific examples include potassium salts or sodium salts of fatty acids such as capric acid, lauric acid, myristic acid, palmitic acid, oleic acid and stearic acid.
As a dispersion medium, water is usually used, and a water-soluble organic solvent such as methanol and ethanol may be contained as long as stability during polymerization is not hindered.
Examples of the radical polymerization initiator include persulfates such as ammonium persulfate and potassium persulfate, organic peroxides, and hydrogen peroxide.
In order to adjust the molecular weight of the resulting polymer (B), a chain transfer agent can also be used. Examples of the chain transfer agent include mercaptans such as tert-dodecyl mercaptan and n-dodecyl mercaptan; carbon tetrachloride, thioglycolic acid, diterpene, terpinolene, γ-terpinene, α-methylstyrene dimer, and the like.
The emulsion polymerization temperature can be appropriately selected depending on the type of radical polymerization initiator to be used, but is usually preferably 0 to 100 ° C, more preferably 0 to 80 ° C. The polymerization mode may be either continuous polymerization or batch polymerization. The polymerization reaction can be stopped by adding a polymerization terminator.
Examples of the polymerization terminator include amine compounds such as isopropylhydroxylamine, diethylhydroxylamine, and hydroxylamine, quinone compounds such as hydroquinone and benzoquinone, and sodium nitrite.
After termination of the polymerization reaction, an antioxidant may be added as necessary. After termination of the polymerization reaction, unreacted monomers are removed from the obtained latex as necessary, and then a salt such as sodium chloride, calcium chloride or potassium chloride is used as a coagulant, and an acid such as nitric acid or sulfuric acid as necessary. Is added to adjust the pH of the coagulation system to a predetermined value, the polymer (B) is coagulated, and then the dispersion medium is separated to recover the polymer (B). Next, after washing with water and dehydration, the polymer (B) is obtained by drying. In addition, at the time of coagulation, if necessary, latex and an extending oil that has been made into an emulsified dispersion may be mixed and recovered as an oil-extended polymer (B).

(Solution polymerization method)
As a solution polymerization method for obtaining the polymer (B), a known method can be applied. For example, a farnesene monomer is polymerized in a solvent using a Ziegler catalyst, a metallocene catalyst, and an anion-polymerizable active metal, if desired, in the presence of a polar compound.
Examples of the active metal capable of anion polymerization include alkali metals such as lithium, sodium and potassium; alkaline earth metals such as beryllium, magnesium, calcium, strontium and barium; lanthanoid rare earth metals such as lanthanum and neodymium. Of these, alkali metals and alkaline earth metals are preferable, and alkali metals are more preferable. Further, the alkali metal is preferably used as an organic alkali metal compound.
Examples of the solvent include aliphatic hydrocarbons such as n-butane, n-pentane, isopentane, n-hexane, n-heptane and isooctane; alicyclic hydrocarbons such as cyclopentane, cyclohexane and methylcyclopentane; benzene and toluene And aromatic hydrocarbons such as xylene.
Examples of organic alkali metal compounds include organic monolithium compounds such as methyllithium, ethyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium, hexyllithium, phenyllithium, and stilbenelithium; dilithiomethane, dilithionaphthalene, Polyfunctional organolithium compounds such as 1,4-dilithiobutane, 1,4-dilithio-2-ethylcyclohexane, 1,3,5-trilithiobenzene; sodium naphthalene, potassium naphthalene and the like. Among these, an organic lithium compound is preferable, and an organic monolithium compound is more preferable. The amount of the organic alkali metal compound used is appropriately determined according to the required molecular weight of the farnesene polymer, but is preferably 0.01 to 3 parts by mass with respect to 100 parts by mass of farnesene.
The organic alkali metal compound can also be used as an organic alkali metal amide by reacting with a secondary amine such as dibutylamine, dihexylamine, dibenzylamine and the like.
The polar compound is used to adjust the microstructure of the farnesene site without deactivating the reaction in anionic polymerization. For example, ether compounds such as dibutyl ether, tetrahydrofuran, and ethylene glycol diethyl ether; tetramethylethylenediamine, trimethylamine, and the like 3 Secondary amines; alkali metal alkoxides, phosphine compounds, and the like. The polar compound is preferably used in an amount of 0.01 to 1000 molar equivalents relative to the organic alkali metal compound.

The temperature of the polymerization reaction is usually in the range of −80 to 150 ° C., preferably 0 to 100 ° C., more preferably 10 to 90 ° C. The polymerization mode may be either batch or continuous.
The polymerization reaction can be stopped by adding an alcohol such as methanol or isopropanol as a polymerization terminator. The polymer (B) can be isolated by pouring the obtained polymerization reaction liquid into a poor solvent such as methanol to precipitate the polymer (B), or washing the polymerization reaction liquid with water, separating, and drying. .

(Modified polymer)
The polymer (B) may be used after being modified. Examples of functional groups include amino groups, amide groups, imino groups, imidazole groups, urea groups, alkoxysilyl groups, hydroxyl groups, epoxy groups, ether groups, carboxyl groups, carbonyl groups, mercapto groups, isocyanate groups, nitrile groups, and acid anhydrides. Examples include physical groups.
As a method for producing the modified polymer, for example, before adding a polymerization terminator, tin tetrachloride, dibutyltin chloride, tetrachlorosilane, dimethyldichlorosilane, dimethyldiethoxysilane, tetramethoxysilane which can react with the polymerization active terminal are used. Coupling agents such as tetraethoxysilane, 3-aminopropyltriethoxysilane, tetraglycidyl-1,3-bisaminomethylcyclohexane, 2,4-tolylene diisocyanate, 4,4′-bis (diethylamino) benzophenone, Examples include a method for adding a polymerization terminal modifier such as N-vinylpyrrolidone, N-methylpyrrolidone, 4-dimethylaminobenzylideneaniline, dimethylimidazolidinone, or other modifiers described in JP2011-132298A. . Moreover, maleic anhydride etc. can also be grafted and used for the polymer (B) after isolation.
In this modified polymer, the position of the polymer into which the functional group is introduced may be a polymerization terminal or a side chain of the polymer chain. Moreover, the said functional group can also be used combining 1 type (s) or 2 or more types. The modifying agent is preferably used in an amount of 0.01 to 100 molar equivalents relative to the organic alkali metal compound.

<Carbon black (C)>
The rubber composition for a seismic isolation structure of the present invention preferably contains carbon black from the viewpoint of improving the mechanical strength of the rubber obtained.
Examples of the carbon black that can be used in the present invention include furnace black, channel black, thermal black, acetylene black, and ketjen black.
The average particle size of the carbon black is preferably 5 to 100 nm, more preferably 5 to 80 nm, and still more preferably 5 to 70 nm from the viewpoint of improving the dispersibility of the carbon black and the mechanical strength of the resulting rubber composition.
As a commercial product of furnace black, Mitsubishi Chemical Corporation "Dia Black", Tokai Carbon Co., Ltd. "Shiest" etc. are mentioned, for example. Examples of commercially available acetylene black include “DENKA BLACK” manufactured by Denki Kagaku Kogyo Co., Ltd. As a commercially available product of Ketjen Black, for example, “ECP600JD” manufactured by Lion Corporation can be cited.

From the viewpoint of improving the wettability and dispersibility to the rubber component (A) and the polymer (B), the above-described carbon black is subjected to acid treatment with nitric acid, sulfuric acid, hydrochloric acid or a mixed acid thereof, or in the presence of air. Surface oxidation treatment by heat treatment may be performed. Moreover, you may heat-process at 2,000-3,000 degreeC in presence of a graphitization catalyst from a viewpoint of the mechanical strength improvement of the rubber | gum obtained from the rubber composition of this invention. Examples of the graphitization catalyst include boron, boron oxide (for example, B ₂ O ₂ , B ₂ O ₃ , B ₄ O ₃ , B ₄ O _5, etc.), boron oxo acid (for example, orthoboric acid, metaboric acid, tetra Boric acid, etc.) and salts thereof, boron carbide (eg, B ₄ C, B ₆ C, etc.), boron nitride (BN), and other boron compounds are preferably used.

The particle size of carbon black can be adjusted by pulverization or the like. For carbon black pulverization, high-speed rotary pulverizer (hammer mill, pin mill, cage mill), various ball mills (rolling mill, vibration mill, planetary mill), stirring mill (bead mill, attritor, distribution pipe mill, annular mill) Etc. can be used.
The average particle size of carbon black can be determined by measuring the particle diameter with a transmission electron microscope and calculating the average value.

  The content of carbon black (C) with respect to 100 parts by mass of the rubber component (A) is preferably 20 to 120 parts by mass, more preferably 30 to 110 parts by mass, further preferably 40 to 100 parts by mass, and 55 to 90 parts by mass. Even more preferred. When the content of carbon black (C) is within the above range, the processability of the rubber composition for a base-isolated structure is improved, and the mechanical strength, creep resistance and low temperature characteristics of the resulting rubber are improved.

<Fillers other than carbon black (D)>
The rubber composition for a seismic isolation structure of the present invention may contain a filler (D) other than the carbon black as necessary for the purpose of adjusting the hardness, reducing the production cost by blending the filler, and the like. .
The filler other than the carbon black is appropriately selected according to the use. For example, organic filler, silica, clay, talc, mica, calcium carbonate, magnesium hydroxide, aluminum hydroxide, barium sulfate, titanium oxide, glass One or more inorganic fillers such as fibers, fibrous fillers, and glass balloons can be used.
When the rubber composition for a seismic isolation structure of the present invention contains the filler (D), the content is preferably 0.1 to 120 parts by mass, and 5 to 90 parts per 100 parts by mass of the rubber component (A). A mass part is more preferable, and 10-80 mass parts is still more preferable.

<Vulcanizing agent (E)>
The rubber composition for a seismic isolation structure of the present invention preferably contains a vulcanizing agent (E) from the viewpoint of imparting creep resistance properties, low temperature properties and mechanical strength to the resulting rubber.
Examples of the vulcanizing agent (E) include sulfur and sulfur compounds. These may be used alone or in combination of two or more.
When the rubber composition for a base-isolated structure of the present invention contains the vulcanizing agent (E), the content is preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the rubber component (A). More preferably, 5-10 mass parts is more preferable, and 0.8-5 mass parts is still more preferable.

<Vulcanization accelerator (F)>
When the rubber composition for a base-isolated structure of the present invention contains the vulcanizing agent (E), it is preferable to contain a vulcanization accelerator (F).
Examples of the vulcanization accelerator (F) include guanidine compounds, sulfenamide compounds, thiazole compounds, thiuram compounds, thiourea compounds, dithiocarbamic acid compounds, aldehyde-amine compounds or aldehyde-ammonia compounds, Examples include imidazoline compounds and xanthate compounds. Examples of the guanidine compound include 1,3-diphenylguanidine, and examples of the sulfenamide compound include N- (tert-butyl) -2-benzothiazole sulfenamide and N-cyclohexyl-2-benzothiazolyl. Examples of the thiuram-based compound such as rusulfenamide include tetrabutylthiuram disulfide. These may be used alone or in combination of two or more.
When the rubber composition for a base-isolated structure of the present invention contains the vulcanization accelerator (F), the content is preferably 0.1 to 15 parts by mass with respect to 100 parts by mass of the rubber component (A), 0.1-10 mass parts is more preferable, and 0.1-8 mass parts is still more preferable.

<Vulcanization aid (G)>
When the rubber composition for a seismic isolation structure of the present invention contains the vulcanizing agent (E), it is preferable to contain a vulcanization aid (G).
Examples of the vulcanization aid (G) include fatty acids such as stearic acid, metal oxides such as zinc white, and fatty acid metal salts such as zinc stearate. These may be used alone or in combination of two or more.
When the rubber composition for a base-isolated structure of the present invention contains the vulcanization aid (G), the content is preferably 0.1 to 15 parts by mass with respect to 100 parts by mass of the rubber component (A), 1-10 mass parts is more preferable.

<Other ingredients>
(Silane coupling agent)
In the case where the rubber composition for a seismic isolation structure of the present invention contains silica as a filler (D) other than the carbon black, it is preferable to contain a silane coupling agent. Examples of the silane coupling agent include sulfide compounds, mercapto compounds, vinyl compounds, amino compounds, glycidoxy compounds, nitro compounds, and chloro compounds.
These silane coupling agents may be used individually by 1 type, and may use 2 or more types together. Among them, from the viewpoint of a large addition effect and from the viewpoint of cost, sulfide compounds such as bis (3-triethoxysilylpropyl) disulfide and bis (3-triethoxysilylpropyl) tetrasulfide, 3-mercaptopropyltrimethoxysilane and the like Mercapto compounds are preferred.

  When the rubber composition for a base-isolated structure of the present invention contains a silane coupling agent, the content is preferably 0.1 to 30 parts by mass, and 0.5 to 20 parts by mass with respect to 100 parts by mass of silica. Part is more preferable, and 1 to 15 parts by mass is still more preferable. When the content of the silane coupling agent is within the above range, the dispersibility of silica, the coupling effect, and the reinforcing property are improved.

(Plasticizers other than polymer (B))
The rubber composition for a seismic isolation structure of the present invention is intended to improve processability, fluidity, damping characteristics, etc., and if necessary, silicon oil, aroma oil, TDAE (Treated Distilled Aromatic Extracts), MES (Mild Extracted) Solvates), RAE (Residual Aromatic Extracts), paraffin oil, naphthenic oil and other process oils; aliphatic hydrocarbon resins, alicyclic hydrocarbon resins, C9 resins, rosin resins, coumarone / indene resins, phenol resins Resin components such as: Low molecular weight polybutadiene, low molecular weight polyisoprene, low molecular weight styrene butadiene copolymer, low molecular weight styrene isoprene copolymer, and other liquid polymers may be included as plasticizers. The weight average molecular weight (Mw) of the liquid polymer is preferably 500 to 100,000 from the viewpoint of processability. Of these, process oil, particularly TDAE, is preferable from the viewpoint of flexibility at a low temperature of the rubber composition for a seismic isolation structure.
When the rubber composition for a base-isolated structure of the present invention contains the process oil, resin component or liquid polymer as a softening agent, the content thereof is 1 to 50 mass with respect to 100 mass parts of the rubber component (A). Part is preferable, 1-30 parts by mass is more preferable, and 1-15 parts by mass is still more preferable.

The rubber composition for a seismic isolation structure of the present invention is an anti-aging agent, an antioxidant, if necessary, for the purpose of improving weather resistance, heat resistance, oxidation resistance, etc., as long as the effects of the invention are not impaired. Waxes, lubricants, light stabilizers, scorch inhibitors, processing aids, colorants such as pigments and dyes, flame retardants, antistatic agents, matting agents, antiblocking agents, UV absorbers, mold release agents, foaming agents, You may contain 1 type, or 2 or more types of additives, such as an antibacterial agent, a fungicide, and a fragrance | flavor.
Examples of the antioxidant include hindered phenol compounds, phosphorus compounds, lactone compounds, hydroxyl compounds, and the like.
Examples of the antiaging agent include amine-ketone compounds, imidazole compounds, amine compounds, phenol compounds, sulfur compounds, and phosphorus compounds. For example, “NOCRACK 6C” (N-phenyl-N ′-(1,3-dimethylbutyl) -p-phenylenediamine) manufactured by Ouchi Shinsei Chemical Co., Ltd., Kawaguchi Chemical Co., Ltd. “ANTAGE RD” (2,2, 4-trimethyl-1,2-dihydroquinoline polymer) and the like.
Examples of the lubricant include “EF44” manufactured by Straktor, “HT266” manufactured by Straktor, “Kaowax EB-FF” manufactured by Kao Corporation, and “Diamid O-200” manufactured by Nippon Kasei Co., Ltd.

  The rubber composition for a seismic isolation structure according to the present invention can be used after being vulcanized by using the vulcanizing agent (E) and by being crosslinked by adding a crosslinking agent. Examples of the crosslinking agent include oxygen, organic peroxide, phenol resin and amino resin, quinone and quinonedioxime derivatives, halogen compounds, aldehyde compounds, alcohol compounds, epoxy compounds, metal halides and organic metal halides, silane compounds, etc. Is mentioned. These may be used alone or in combination of two or more. As for content of a crosslinking agent, 0.1-10 mass parts is preferable with respect to 100 mass parts of rubber components (A).

  The manufacturing method of the rubber composition for seismic isolation structures of this invention is not specifically limited, What is necessary is just to mix each said component uniformly. As a method of uniformly mixing, for example, a tangential or meshing hermetic kneader such as a kneader ruder, brabender, banbury mixer, internal mixer, single screw extruder, twin screw extruder, mixing roll, roller, etc. Usually, and can be carried out in a temperature range of 70 to 270 ° C.

[Seismic isolation structure]
The seismic isolation structure of the present invention uses at least a part of the rubber composition for a seismic isolation structure of the present invention. Specifically, a rubber obtained by cross-linking the rubber composition for a base-isolated structure of the present invention by a general method, preferably a rubber obtained by vulcanization is preferably used at least in part. .
The extraction rate of the plasticizer contained in the rubber obtained by crosslinking the rubber composition for a base-isolated structure of the present invention is preferably 20% by mass or less, more preferably 15% by mass or less, and still more preferably 10% by mass or less. 7 mass% or less is particularly preferable. If the extraction rate of the plasticizer is within the above range, a seismic isolation structure excellent in low migration performance can be obtained. The “plasticizer” used herein means both the polymer (B) and a plasticizer other than the polymer (B).
In addition, the said extraction rate is the plasticizer extracted when extracting for 48 hours at 23 degreeC using 400 ml of toluene with respect to 2g of rubber | gum obtained by bridge | crosslinking the rubber composition for seismic isolation structures of this invention. It can be calculated from the quantity.

  The structure of the seismic isolation structure of the present invention is not particularly limited. For example, a soft layer made of rubber obtained from the rubber composition for a seismic isolation structure, and a hard layer made of steel plate or the like, each having a plurality of layers. A structure obtained by alternately laminating and coating the outer periphery with a rubber material or the like can be preferably exemplified. The seismic isolation structure having such a structure is preferable because it has both horizontal rigidity and vertical rigidity. That is, the seismic isolation structure of the present invention is preferably a seismic isolation structure having a laminated structure in which a plurality of steel plates and rubber layers obtained from the rubber composition for a seismic isolation structure are alternately laminated.

Next, an example of the seismic isolation structure of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view of the seismic isolation structure of the present invention, wherein 1 is a steel plate, 2 is a rubber layer obtained from the rubber composition for seismic isolation structure (hereinafter also referred to as “rubber layer 2”). 3 and 3 'are flanges, 4 is a covering rubber layer.
In the seismic isolation structure of FIG. 1, the steel plates 1 and the rubber layers 2 are alternately laminated in three layers, and the layers are integrated by vulcanization adhesion. In this seismic isolation structure, since the rubber composition for a seismic isolation structure of the present invention is used, it has both horizontal rigidity and vertical rigidity. In this manner, the vertical deformation is significantly suppressed by interposing the steel plate 1 between the rubber layers 2.
Although there is no restriction | limiting in particular in the magnitude | size of the seismic isolation structure of this invention, Usually the cylindrical shape of the range of diameter 500-2,000 mm and the height 200-800 mm is preferable.
In the seismic isolation structure of the present invention, the total number of layers of the steel plate 1 and the rubber layer 2 is not particularly limited, but usually 4 to 100 layers are preferable.
In the seismic isolation structure shown in FIG. 1, a covering rubber layer 4 is provided on a cylindrical side surface for the purpose of preventing deterioration of the steel plate 1 and the rubber layer 2. The material constituting the covering rubber layer 4 is not particularly limited as long as it is a rubber material having excellent weather resistance. For example, butyl rubber (IIR), urethane rubber, ethylene-propylene copolymer rubber (EPM), ethylene-propylene-diene. Copolymer rubber (EPDM) and ethylene-vinyl acetate copolymer rubber (EVA) are used. Moreover, you may use the rubber | gum obtained from the rubber composition for seismic isolation structures of this invention for the covering rubber layer 4. FIG.

  The flanges 3 and 3 ′ in the seismic isolation structure of FIG. 1 are usually made of a steel plate that is thicker than the steel plate 1. The seismic isolation structure of the present invention is used by embedding these flanges in concrete and fastening them to the base plate with bolts.

  The seismic isolation structure of the present invention is used in combination with a seismic isolation structure such as a natural rubber-based laminated rubber not containing the polymer (B), a high-damping laminated rubber, a laminated rubber with a lead plug, a sliding bearing, and a rolling bearing. You can also. In addition, an oil damper, a steel damper, a lead damper, or the like can be used in combination for the purpose of adjusting the damping characteristics.

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.
Each component used in the examples and comparative examples is as follows.
<Rubber component (A)>
Natural rubber: "STR20" (natural rubber made in Malaysia)
<Polymer (B)>
Polyfarnesene (B-1) and (B-2) produced in Production Examples 1 and 2 to be described later, and farnesene copolymer (B-3) produced in Production Example 3

<Carbon black (C)>
C-1: Diamond Black H (Mitsubishi Chemical Corporation)
(Average particle size 30 nm) (ASTM display N330)

<Vulcanizing agent (E)>
Sulfur (fine sulfur 200 mesh, manufactured by Tsurumi Chemical Co., Ltd.)
<Vulcanization accelerator (F)>
Noxeller CZ (Ouchi Shinsei Chemical Industry Co., Ltd., N-cyclohexyl-2-benzothiazolylsulfenamide)
<Vulcanization aid (G)>
・ Stearic acid: LUNAC S-20 (manufactured by Kao Corporation)
・ Zinc flower: Zinc oxide (manufactured by Sakai Chemical Industry Co., Ltd.)
<Others>
Anti-aging agent: NOCRACK 6C (Ouchi Shinsei Chemical Co., Ltd., N-phenyl-N′-
(1,3-Dimethylbutyl) -p-phenylenediamine)
・ TDAE (plasticizer): VivaTec500 (manufactured by H & R)
<Polymer (X)>
Polyisoprene (X-1) produced in Comparative Production Example 1 described later

Production Example 1: Production of polyfarnesene (B-1) In a pressure-resistant container purged with nitrogen and dried, 1,200 g of hexane as a solvent and 5.0 g of n-butyllithium (17% by mass hexane solution) as an initiator were charged, and 50 After raising the temperature to 0 ° C., 1,180 g of β-farnesene was added and polymerized for 1 hour. The obtained polymerization reaction liquid was treated with methanol, and the polymerization reaction liquid was washed with water. The polymerization reaction solution after washing and water were separated and dried under reduced pressure at 70 ° C. for 12 hours to obtain polyfarnesene (B-1) having physical properties shown in Table 1.

Production Example 2: Production of polyfarnesene (B-2) In a pressure-resistant container purged with nitrogen and dried, 1,200 g of cyclohexane as a solvent and 42.6 g of sec-butyllithium (10.5 mass% hexane solution) as an initiator were added. After charging and heating to 50 ° C., 1,880 g of β-farnesene was added and polymerization was performed for 1 hour. The obtained polymerization reaction liquid was treated with methanol, and the polymerization reaction liquid was washed with water. The polymerization reaction solution after washing and water were separated and dried under reduced pressure at 70 ° C. for 12 hours to obtain polyfarnesene (B-2) having physical properties shown in Table 1.

Production Example 3 Production of β-Farnesene / Styrene Random Copolymer (B-3) In a pressure-resistant container purged with nitrogen and dried, 1,280 g of cyclohexane as a solvent and sec-butyllithium (10.5% by mass) as an initiator 156 g of cyclohexane solution) was heated to 50 ° C., then 3.5 g of tetrahydrofuran was added, and a mixture of styrene (a) and β-farnesene (b) prepared in advance (880 g of styrene (a) and β-farnesene) (B) 880 g was mixed in a cylinder) 1,760 g was added at 10 ml / min and polymerized for 1 hour. The obtained polymerization reaction liquid was treated with methanol, and the polymerization reaction liquid was washed with water. The polymerization reaction solution after washing and water were separated and dried under reduced pressure at 70 ° C. for 12 hours to obtain a β-farnesene / styrene random copolymer (B-3) having physical properties shown in Table 1.

Comparative Production Example 1: Production of polyisoprene (X-1) 600 g of hexane and 44.9 g of n-butyllithium (17% by mass hexane solution) were charged into a pressure-resistant container purged with nitrogen and dried, and the temperature was raised to 70 ° C. Then, 2,050 g of isoprene was added and polymerized for 1 hour. After adding methanol to the obtained polymerization reaction solution, the polymerization reaction solution was washed with water. Water was separated, and the polymerization reaction solution was dried under reduced pressure at 70 ° C. for 12 hours to obtain polyisoprene (X-1) having physical properties shown in Table 1.

In addition, the measuring method of the weight average molecular weight (Mw), molecular weight distribution (Mw / Mn), and melt viscosity of a polymer (B) and polyisoprene is as follows.
(Method of measuring weight average molecular weight and molecular weight distribution)
Mw and Mw / Mn of the polymer (B) and polyisoprene were obtained by GPC (gel permeation chromatography) as a standard polystyrene equivalent molecular weight. The measuring apparatus and conditions are as follows.
・ Device: GPC device “GPC8020” manufactured by Tosoh Corporation
Separation column: “TSKgel G4000HXL” manufactured by Tosoh Corporation
Detector: “RI-8020” manufactured by Tosoh Corporation
・ Eluent: Tetrahydrofuran ・ Eluent flow rate: 1.0 ml / min ・ Sample concentration: 5 mg / 10 ml
-Column temperature: 40 ° C

(Measuring method of melt viscosity)
The melt viscosity at 38 ° C. of the polymer (B) was measured with a Brookfield viscometer (manufactured by BROOKFIELD ENGINEERING LABS. INC.).

Examples 1 to 3 and Comparative Examples 1 and 2
According to the blending ratio (parts by mass) described in Tables 2 and 3, rubber component (A), polymer (B), carbon black (C), polymer (X) (polyisoprene (X-1)), Sulfur aid (G), anti-aging agent and TDAE were each put into a closed Banbury mixer and kneaded for 6 minutes so that the starting temperature was 60 ° C. and the resin temperature was 160 ° C., then taken out of the mixer to room temperature. Cooled down. Next, this mixture was again put into a Banbury mixer, and a vulcanizing agent (E) and a vulcanization accelerator (F) were added and kneaded at 60 ° C. for 6 minutes to obtain a rubber composition. Using the obtained rubber composition, Mooney viscosity and creep resistance were measured by the following methods.
Further, the obtained rubber composition is press-molded (145 ° C., 15 to 20 minutes) to prepare a vulcanized rubber sheet (thickness 2 mm), and the plasticizer extraction rate of the vulcanized rubber sheet based on the following method The low temperature characteristics and hysteresis loss were evaluated. The results are shown in Tables 2 and 3.

(1) Workability (Mooney viscosity)
As an index of processability of the rubber composition, the Mooney viscosity (ML _{1 + 4} ) of the rubber composition before vulcanization was measured at 100 ° C. in accordance with JIS K6300. The values of Examples 1 to 3 and Comparative Example 1 are relative values when the value of Comparative Example 2 is 100. In addition, workability is so favorable that a numerical value is small.

(2) Creep resistance (compression set)
The rubber compositions obtained in each Example and Comparative Example were compression molded at 145 ° C. for 30 minutes, and a cylindrical test piece having a diameter of 29.0 ± 0.5 mm and a thickness of 12.5 ± 0.5 mm (d0) was obtained. Produced. In accordance with JIS K6262, this columnar test piece was subjected to compression deformation by 25% using a spacer thickness of 9.4 mm (d1), held in a 70 ° C. atmosphere for 22 hours, and then released from compression. Thereafter, the thickness (d2: mm) of the cylindrical test piece when left in an atmosphere at 23 ° C. and 50% relative humidity for 30 minutes was measured, and compression set (%) = 100 × (d0−d2) / It calculated | required by (d0-d1). The values of Examples 1 to 3 and Comparative Example 1 are relative values when the value of Comparative Example 2 is 100. The lower the value, the better the creep resistance.

(3) Low migration performance (extraction rate of plasticizer)
Extraction of polymer (B), polyisoprene, and TDAE extracted from vulcanized rubber was carried out at 23 ° C. for 48 hours using 400 ml of toluene to 2 g of vulcanized rubber produced by press molding in Examples and Comparative Examples. The total extraction rate was measured to evaluate the low migration performance. The lower the extraction rate, the lower the plasticizer is.

(4) Low temperature characteristics (−20 ° C. E ′ / 25 ° C. E ′)
A test piece having a length of 40 mm × width of 7 mm was cut out from a vulcanized rubber sheet obtained by press-molding the rubber compositions prepared in Examples and Comparative Examples, and a dynamic strain measurement device manufactured by GABO was used. E ′ at temperatures of 25 ° C. and −20 ° C. was measured under the conditions of 0.5% and dynamic strain of 0.1%, and E ′ at −20 ° C./E ′ at 25 ° C. was used as an index of low temperature characteristics. The numerical values of Examples 1 to 3 and Comparative Example 1 are relative values when the value of Comparative Example 2 is set to 100. The lower the value, the better the low temperature characteristics.

(5) Attenuation characteristics (hysteresis loss)
A JIS No. 3 dumbbell-shaped test piece was cut out from a vulcanized rubber sheet obtained by press-molding the rubber compositions prepared in Examples and Comparative Examples. Using an Instron tensile tester, tensile deformation was performed under the conditions of a measurement temperature of 23 ° C., a deformation rate of 200 mm / min, and a tensile elongation of 100%, and the elongation process and the contraction process were repeated three times. Hysteresis loss was calculated based on the following formula using the energy values of the third extension process and contraction process. The numerical values of Examples 1 to 3 and Comparative Example 1 are relative values when the value of Comparative Example 2 is set to 100.
[Hysteresis loss] = {[Energy in the third extension process] − [Energy in the third contraction process]} / [Energy in the third extension process]

  The rubber compositions for base-isolated structures of Examples 1 and 2 use β-farnesene homopolymer (B), and the Mooney viscosity is comparable to or smaller than Comparative Examples 1 and 2. Excellent workability due to its value. Further, the rubber obtained from the rubber composition for seismic isolation structures of Examples 1 and 2 has a plasticizer extraction rate that is the same as or smaller than that of Comparative Examples 1 and 2, and has low plasticizer migration. Excellent. Furthermore, the rubbers obtained in Examples 1 and 2 have a small damping characteristic value (hysteresis loss value), excellent linear performance, high restoring ability, and excellent creep resistance. It has high durability. The rubbers obtained in Examples 1 and 2 have a small hysteresis loss and are excellent in flexibility at low temperatures, and therefore can be particularly preferably used as a natural rubber-based laminated rubber.

  As is clear from the results of Example 3 and Comparative Example 2, when the farnesene copolymer (B) containing 50% by mass of the aromatic vinyl compound is used, a rubber having a large hysteresis loss and excellent energy absorption performance is obtained. And can be particularly preferably used as a high-damping laminated rubber. Further, Example 3 using the farnesene copolymer (B) has a lower plasticizer extraction rate than that of Comparative Example 2, and is excellent in low migration performance.

1: Steel plate
2: Rubber layer obtained from the rubber composition for seismic isolation structure 3: Flange 3 ': Flange 4: Covered rubber layer

Claims (7)

  A rubber composition for a base-isolated structure comprising 0.1 to 100 parts by mass of a farnesene polymer (B) with respect to 100 parts by mass of a rubber component (A) composed of at least one of synthetic rubber and natural rubber.   Furthermore, the rubber composition for seismic isolation structures of Claim 1 which contains 20-120 mass parts of carbon black (C) with respect to 100 mass parts of said rubber components (A).   The rubber composition for a seismic isolation structure according to claim 1 or 2, wherein the polymer (B) has a weight average molecular weight of 2,000 to 500,000.   The rubber composition for a base-isolated structure according to any one of claims 1 to 3, wherein the polymer (B) is a homopolymer of β-farnesene.   The polymer (B) is a copolymer containing a monomer unit (a) derived from a monomer other than β-farnesene and a monomer unit (b) derived from β-farnesene. The rubber composition for a seismic isolation structure according to any one of?   The base isolation structure which used the rubber composition for base isolation structures in any one of Claims 1-5 for at least one part.   The seismic isolation structure according to claim 6, which has a laminated structure in which steel plates and rubber obtained from the rubber composition for a seismic isolation structure are alternately laminated.