Vibration damper

Abstract

The present invention provides a vibration damper having excellent damping properties.　Provided is a vibration damper comprising, as a constituent member, a viscoelastic body that comprises a rubber composition which contain components (A) to (C), wherein in an arbitrary 1 μm × 1 μm square region of a scanning transmission electron microscope image of the viscoelastic body captured at 150,000 times magnification, the number of aggregates in which three or more calcium carbonate particles are connected is 3-15.　Component (A) is a styrene-isoprene-styrene copolymer and / or a styrene-butadiene-styrene copolymer. Component (B) is one or more components selected from the group consisting of ethylene-propylene-diene terpolymers, ethylene-butene-diene terpolymers, and butadiene rubbers. Component (C) is calcium carbonate.

Description

Vibration damping damper

[0001] This invention relates to a vibration damping damper. More specifically, it relates to a vibration damping damper suitable for applications such as vibration control and seismic isolation in the civil engineering and construction fields.

[0002] In the fields of civil engineering and construction, vibration control devices and seismic isolation devices, particularly vibration dampers (also called seismic dampers) used in large structures such as bridges and buildings, are required to absorb vibration energy caused by earthquakes and other events. This requires not only that the vibration control performance is achieved through the mechanical structural elements of the vibration damper, but also that high damping is achieved through the viscoelastic material (rubber material) used in the vibration damper.

[0003] Furthermore, with the inclusion of measures to address long-period ground motion (convergence time of 600 seconds) for high-rise buildings in the 2016 Ministry of Land, Infrastructure, Transport and Tourism guidelines, there is a growing need for vibration control dampers that do not experience a decrease in damping characteristics even with long-convergence tremors.

[0004] Conventional vibration damping dampers primarily use viscoelastic materials mainly composed of styrene-isoprene-styrene (SIS) copolymers (see, for example, Patent Documents 1 and 2). In addition, to induce friction damping, it has been considered to incorporate ethylene-propylene-diene ternary copolymers or small-particle fillers such as silica or calcium carbonate into the SIS copolymer.

[0005] Japanese Patent Publication No. 2014-227521 Japanese Patent Publication No. 2015-183110

[0006] As mentioned above, various studies have been conducted focusing on the damping characteristics of vibration dampers. However, research on the relationship between the dispersion form of fillers in the viscoelastic material that constitutes the vibration damper and the damping characteristics, and in particular the relationship between the dispersion form of calcium carbonate and the damping characteristics, has not yet progressed sufficiently.

[0007] This invention has been made in view of these circumstances, and provides a vibration damping damper with excellent damping characteristics.

[0008] In the process of investigating combinations of polymer components and filler components from the viewpoint of improving the damping characteristics of viscoelastic materials that are constituent members of vibration damping dampers, the inventors focused on the dispersion form of calcium carbonate in a polymer matrix containing (A) at least one of styrene-isoprene-styrene (SIS) copolymer and styrene-butadiene-styrene (SBS) copolymer, and (B) one or more selected from the group consisting of ethylene-propylene-diene terpolymer (EPDM), ethylene-butene-diene terpolymer (EBT), and butadiene rubber (BR). In the process of diligently conducting research from this viewpoint, the inventors discovered a new and different finding regarding the relationship between the dispersion form of calcium carbonate and damping characteristics. That is, conventionally, it was generally considered preferable to increase the dispersibility of calcium carbonate in the polymer matrix, i.e., to reduce the proportion of aggregates of calcium carbonate particles as much as possible, in order to improve various properties. However, the inventors newly discovered that in the case of calcium carbonate in the aforementioned specific polymer matrix, the damping characteristics may be inhibited as the dispersibility increases. Based on these new findings, the inventors conducted further research and discovered that by having a specific dispersion form, namely a state in which three or more calcium carbonate particles are linked together, and by controlling the number of aggregates of three or more linked calcium carbonate particles within a specific range, the damping characteristics of the viscoelastic material that constitutes the vibration damping damper can be effectively improved.

[0009] In other words, the gist of the present invention is as follows: [1] A vibration damping damper comprising a viscoelastic body made of a rubber composition containing the following components (A) to (C), wherein the number of aggregates of three or more calcium carbonate particles in any 1 μm × 1 μm square region of a scanning transmission electron microscope image of the viscoelastic body taken at a magnification of 150,000 is in the range of 3 to 15. (A) At least one of styrene-isoprene-styrene copolymer and styrene-butadiene-styrene copolymer (B) One or more selected from the group consisting of ethylene-propylene-diene terpolymer, ethylene-butene-diene terpolymer, and butadiene rubber (C) Calcium carbonate [2] The vibration damping damper according to [1], wherein the number of aggregates of three or more calcium carbonate particles is in the range of 5 to 9. [3] The vibration damping damper according to [1] or [2], wherein the calcium carbonate content is 15 to 100 parts by mass per 100 parts by mass of the total of components (A) and (B). [4] The vibration damping damper according to any one of [1] to [3], wherein the particle shape of the calcium carbonate is cubic. [5] The vibration damping damper according to any one of [1] to [4], wherein the average particle diameter of the calcium carbonate is 10 to 300 nm.

[0010] According to the present invention, a vibration damping damper with excellent damping characteristics can be provided.

[0011] This is a front view showing an example of a vibration damping damper. This is a cross-sectional another example of a vibration damping damper. This is a schematic diagram showing the installation state of the vibration damping damper. This is a schematic diagram of the apparatus used to perform the evaluation method described in the example. This is a diagram showing the load-strain loop curve in the evaluation method described in the example. This is a diagram showing a scanning transmission electron microscope image of Example 1. This is a diagram showing an elemental mapping image of Example 1. This is a diagram showing a magnified image (1 μm × 1 μm square area) of the scanning transmission electron microscope image of Example 1.

[0012] Next, embodiments of the present invention will be described in detail. However, the present invention is not limited to these embodiments.

[0013] In this specification, "X or / and Y (where X and Y are any configuration)" means at least one of X and Y, and can mean X only, Y only, or X and Y. Furthermore, in the numerical ranges described in steps in this specification, the upper or lower limit of one step in the numerical range can be arbitrarily combined with the upper or lower limit of another step in the numerical range. In addition, in the numerical ranges described in this specification, the upper or lower limit of that numerical range can be replaced with the values ​​shown in the examples.

[0014] <Vibration Damping Damper> A vibration damping damper according to one embodiment of the present invention (hereinafter sometimes referred to as "this vibration damping damper") is a vibration damping damper in which a viscoelastic body made of a rubber composition containing the following components (A) to (C) (hereinafter sometimes referred to as "this rubber composition") is a constituent member, characterized in that the number of aggregates of three or more calcium carbonate particles in any 1 μm × 1 μm square region of a scanning transmission electron microscope image of the viscoelastic body taken at a magnification of 150,000 is in the range of 3 to 15. (A) At least one of styrene-isoprene-styrene copolymer and styrene-butadiene-styrene copolymer (B) One or more selected from the group consisting of ethylene-propylene-diene terpolymer, ethylene-butene-diene terpolymer, and butadiene rubber (C) Calcium carbonate

[0015] This vibration damping damper is a viscoelastic material made of a rubber composition containing components (A) to (C), and because the calcium carbonate particles are dispersed in a different manner than in conventional materials, it exhibits excellent damping characteristics.

[0016] Specifically, by setting the number of aggregates, each consisting of three or more calcium carbonate particles, in any 1 μm × 1 μm square region of a scanning transmission electron microscope image of a viscoelastic material made from a rubber composition containing components (A) to (C) at a magnification of 150,000, to within the range of 3 to 15, excellent damping characteristics can be obtained. If the number of aggregates is outside the above range, it is not possible to obtain the excellent damping characteristics of the present invention. For example, if there are almost no aggregates, as was previously considered preferable, for example, if the aggregates are dispersed to less than three, it is not possible to obtain the excellent damping characteristics of the present invention.

[0017] Furthermore, in a preferred embodiment of this vibration damping damper, from the viewpoint of exhibiting particularly excellent damping characteristics, the number of aggregates is preferably in the range of 3 to 12, and more preferably in the range of 5 to 9. The number of aggregates can also be appropriately adjusted within the above range, for example, it may be in the range of 6 to 9.

[0018] The number of calcium carbonate particles forming the aggregate is not particularly limited as long as there are three or more, but for example, the number of calcium carbonate particles forming the aggregate is about 3 to 10. In one embodiment of the present invention, it is preferable that the number of aggregates, each consisting of 3 to 10 calcium carbonate particles, is in the range of 3 to 15.

[0019] The reason why the above-mentioned excellent effects are obtained by this vibration damping damper is not entirely clear, but the inventors believe that in order to achieve excellent damping performance, it is necessary to effectively generate frictional force. In the present invention, in the polymer matrix containing components (A), (B), and (C), the frictional force is significantly improved by the friction between aggregates containing three or more calcium carbonate particles. In addition, the interparticle attractive force of the calcium carbonate particles constituting the aggregates and the mutual frictional effect between the calcium carbonate particles and specific polymer components combine to further significantly improve the frictional force, thereby obtaining excellent damping characteristics. Furthermore, noting that poor dispersion of calcium carbonate and too many aggregates tend to make it difficult to exhibit frictional damping, and conversely, too good dispersion requires a certain level of displacement to exhibit frictional damping, the inventors believe that in the present invention, by controlling the number of specific aggregates within a specific range, the frictional damping effect can be synergistically expressed, thus obtaining excellent damping characteristics.

[0020] The number of aggregates can be determined according to the following standard method. Specifically, a smooth surface is prepared on the viscoelastic material using a microtome, and a 1 μm × 1 μm area is identified in the scanning transmission electron microscope image taken at a magnification of 150,000x. This area is then visually observed, and the number of aggregates consisting of three or more calcium carbonate particles is counted.

[0021] Specifically, for example, first, a viscoelastic material is observed using a scanning transmission electron microscope (SEM) at a magnification of 150,000x, and a SEM image is acquired. Next, an elemental mapping image is acquired using an energy-dispersive X-ray spectrometer attached to the SEM, and calcium carbonate is identified in the microscope image by detecting Ca atoms derived from calcium carbonate. Then, the elemental mapping image and a magnified image of the electron microscope image are compared, and the number of aggregates contained in a 1 μm x 1 μm area within the electron microscope image is visually measured.

[0022] Furthermore, in this specification, "aggregates of three or more calcium carbonate particles" observed in scanning transmission electron microscope images means aggregates comprising at least a first calcium carbonate particle, a second calcium carbonate particle in contact with the first calcium carbonate particle, and a third calcium carbonate particle in contact with at least one of the first and second calcium carbonate particles. Specifically, it is an aggregate in which the outline of the first calcium carbonate particle and the outline of the second calcium carbonate particle are in contact, and which comprises at least a third calcium carbonate particle in contact with the first and second calcium carbonate particles.

[0023] Furthermore, the term "aggregate of three or more calcium carbonate particles" observed in scanning transmission electron microscope images implies not only that the calcium carbonate particles are in contact, but also that the interparticle distance is within 20 nm, considering the interparticle attractive forces of calcium carbonate particles. In other words, if the interparticle distance between any two calcium carbonate particles is within 20 nm, they can be considered to be in contact due to chemical and physical interparticle attractive forces. Therefore, an aggregate containing at least a first calcium carbonate particle, a second calcium carbonate particle whose interparticle distance from the first calcium carbonate particle is within 20 nm, and a third calcium carbonate particle whose interparticle distance from the first calcium carbonate particle and at least one of the second calcium carbonate particles is within 20 nm can be considered an "aggregate of three or more calcium carbonate particles." More specifically, if the shortest straight-line distance between the outlines of any two calcium carbonate particles is 20 nm or less, or more precisely, if the shortest straight-line distance between any point constituting the outline of any two calcium carbonate particles and any point constituting the outline of another two calcium carbonate particles is 20 nm or less, then the two calcium carbonate particles can be considered to be in contact with each other, and are therefore considered to be an aggregate of three or more connected calcium carbonate particles.

[0024] The following provides a detailed explanation of this vibration damping damper.

[0025] In one embodiment of this vibration damping damper, the rubber composition contains at least component (A) and component (B) as polymer components. Preferably, the polymer component is a polymer component mainly composed of component (A).

[0026] The term "main component" of the above polymer component means that component (A) accounts for 50% by mass or more of the total amount (100% by mass) of the above polymer component, and may be 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more.

[0027] Furthermore, in one embodiment of this vibration damping damper, from the viewpoint of damping characteristics, it is preferable that the polymer component consists only of component (A) and component (B), but it is not limited thereto. For example, the content ratio of component (A) and component (B) in the total amount (100% by mass) of the polymer component may be 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, etc.

[0028] (A) At least one of styrene-isoprene-styrene (SIS) copolymer and styrene-butadiene-styrene (SBS) copolymer. This rubber composition contains at least one of styrene-isoprene-styrene (SIS) copolymer and styrene-butadiene-styrene (SBS) copolymer. Styrene-isoprene-styrene (SIS) copolymer and styrene-butadiene-styrene (SBS) copolymer are styrene-based elastomers, and those conventionally known in the art can be used as appropriate.

[0029] (Styrene-isoprene-styrene (SIS) copolymer) The diblock content of styrene-isoprene in the SIS copolymer is not particularly limited, but is preferably 50 to 95% by mass, and more preferably 60 to 90% by mass. Such a diblock content is superior in obtaining high damping characteristics. The above diblock amount is a value measured by gel permeation chromatography (GPC).

[0030] The styrene content in the SIS copolymer is not particularly limited, but is preferably 10 to 30% by mass, and more preferably 13 to 25% by mass. The above styrene content is a value measured by nuclear magnetic resonance (NMR) spectrometer.

[0031] The number-average molecular weight (Mn) of the SIS copolymer is not particularly limited, but is preferably 100,000 to 200,000, and more preferably 100,000 to 150,000. In other words, such a small molecular weight is preferable from the viewpoint of decay characteristics. The above number-average molecular weight (Mn) was measured according to gel permeation chromatography (GPC).

[0032] Mooney viscosity of SIS copolymer (ML) 1+4 The temperature (100°C) is not particularly limited, but for example, it is preferably 10 to 50°C, and more preferably 13 to 40°C.

[0033] In this specification, Mooney viscosity is measured in accordance with the provisions of JIS K6300-1:2013, using an L-shaped rotor, with a preheating time of 1 minute, a rotor rotation time of 4 minutes, and a test temperature of 100°C.

[0034] (Styrene-Butadiene-Styrene (SBS) Copolymer) The diblock content of styrene-butadiene in the SBS copolymer is not particularly limited, but is preferably 50 to 95% by mass, and more preferably 60 to 90% by mass. Such a diblock content is superior in obtaining high damping characteristics. The above diblock content is a value measured by gel permeation chromatography (GPC).

[0035] The styrene content in the SBS copolymer is not particularly limited, but is preferably 10 to 30% by mass, and more preferably 13 to 25% by mass. The above styrene content is a value measured by nuclear magnetic resonance (NMR) spectrometer.

[0036] The number average molecular weight (Mn) of the SBS copolymer is not particularly limited, but for example, a range of 100,000 to 200,000 is preferable, and more preferably a range of 100,000 to 150,000. That is, such a small molecular weight is preferable from the viewpoint of attenuation characteristics. The above number average molecular weight (Mn) is a measured value according to gel permeation chromatography (GPC).

[0037] The Mooney viscosity (ML 1+4 (100 °C)) of the SBS copolymer is not particularly limited, but for example, 10 to 50 is preferable, and more preferably 13 to 40.

[0038] In addition, this rubber composition may contain components other than the above as polymer components. For example, styrene-butadiene (SB) copolymers, styrene-isoprene (SI) copolymers, styrene-ethylene-butylene (SEB) copolymers, styrene-ethylene-butylene-styrene (SEBS) copolymers, styrene-ethylene-propylene (SEP) copolymers, styrene-ethylene-propylene-styrene (SEPS) copolymers, and hydrogenated styrenic elastomers such as the above copolymers can be mentioned. These can be used alone or in combination of two or more.

[0039] Examples of commercially available products of component (A) include Quintac 3390, Quintac 3433N, Quintac 3270 (manufactured by Nippon Zeon Co., Ltd.), D1161 (manufactured by Clayton Polymer Co., Ltd.), VECTOR 4411 (manufactured by TSRC Co., Ltd.), and the like.

[0040] <One or more selected from the group consisting of (B) ethylene-propylene-diene terpolymer, ethylene-butene-diene terpolymer, and butadiene rubber> This rubber composition contains one or more selected from the group consisting of ethylene-propylene-diene terpolymer, ethylene-butene-diene terpolymer, and butadiene rubber.

[0041] (Ethylene-propylene-diene terpolymer (EPDM)) Any EPDM conventionally known in the art can be used as appropriate. The ethylene content of the EPDM is not particularly limited, but from the viewpoint of damping characteristics, for example, 5 to 60% by mass is preferred, and more preferably 10 to 40% by mass.

[0042] The propylene content of EPDM is not particularly limited, but from the viewpoint of damping characteristics, for example, it is preferably 5 to 60% by mass, and more preferably 10 to 40% by mass.

[0043] The diene content of EPDM is not particularly limited, but from the viewpoint of damping characteristics, for example, it is preferably 3 to 25% by mass, and more preferably 5 to 15% by mass.

[0044] The diene (third component) of EPDM is preferably a diene monomer having 5 to 20 carbon atoms. Specifically, examples include 1,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene, 2,5-dimethyl-1,5-hexadiene, 1,4-octadiene, 1,4-cyclohexadiene, cyclooctadiene, dicyclopentadiene (DCP), 5-ethylidene-2-norbornene (ENB), 5-butylidene-2-norbornene, 2-methallyl-5-norbornene, and 2-isopropenyl-5-norbornene.

[0045] Mooney viscosity of EPDM (ML) 1+4 The temperature (100°C) is not particularly limited, but is preferably in the range of 30 to 100°C, and more preferably in the range of 35 to 85°C.

[0046] (Ethylene-butene-diene terpolymer (EBT)) Any EBT conventionally known in the art can be used as appropriate. The ethylene content of the EBT is not particularly limited, but is preferably 55% by mass or less, more preferably 35 to 55% by mass, and even more preferably 40 to 53% by mass.

[0047] The butene content in EBT is not particularly limited, but is preferably 35% by mass or more, more preferably 35 to 55% by mass, and even more preferably 38 to 50% by mass.

[0048] The diene content of EBT is not particularly limited, but from the viewpoint of damping characteristics, for example, it is preferably 3 to 25% by mass, and more preferably 5 to 15% by mass.

[0049] The diene (third component) of EBT is preferably a diene monomer having 5 to 20 carbon atoms. Specifically, examples include 1,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene, 2,5-dimethyl-1,5-hexadiene, 1,4-octadiene, 1,4-cyclohexadiene, cyclooctadiene, dicyclopentadiene (DCP), 5-ethylidene-2-norbornene (ENB), 5-butylidene-2-norbornene, 2-methallyl-5-norbornene, and 2-isopropenyl-5-norbornene.

[0050] (Butadiene Rubber (BR)) The butadiene rubber (BR) used in this rubber composition may be any that is conventionally known in the art. Butadiene rubber (BR) is a rubber obtained by polymerizing butadiene as a raw material monomer, and can be obtained, for example, by polymerizing butadiene using a Ziegler catalyst or an alkyllithium initiator.

[0051] The microstructure of butadiene rubber (BR) is not particularly limited, but low-cis-BR with a cis-1,4 bond unit content of 50% by mass or less, for example, 30-40% by mass, or high-cis-BR with 90% by mass or more, can be used as appropriate.

[0052] Butadiene rubber (BR) Mooney viscosity (ML 1+4 (100°C) is not particularly limited, but for example, it is around 30-60, 30-55, or 30-50.

[0053] Examples of commercially available components (B) include EPT K-972, EPT 4045M (both manufactured by Mitsui Chemicals, Inc.), EP104E, EP35, EP65, EP33, and EP98 (all manufactured by JSR Corporation).

[0054] The mixing ratio of component (A) and component (B) in this rubber composition is preferably (A):(B) = 95:5 to 50:50 by mass ratio, and more preferably (A):(B) = 90:10 to 55:45.

[0055] A preferred embodiment of this rubber composition is the combined use of styrene-isoprene-styrene (SIS) copolymer and ethylene-propylene-diene terpolymer (EPDM). The ratio of styrene-isoprene-styrene (SIS) copolymer to ethylene-propylene-diene terpolymer (EPDM) is preferably SIS:EPDM = 95:5 to 50:50 by mass ratio, and more preferably SIS:EPDM = 90:10 to 55:45.

[0056] (C) Calcium Carbonate: It is important that this rubber composition contains calcium carbonate, along with components (A) and (B), among various fillers. Furthermore, as mentioned above, it is important that the calcium carbonate has a specific dispersion form.

[0057] As the calcium carbonate, any calcium carbonate conventionally known in the art can be used as appropriate. Although not particularly limited, from the viewpoint of significantly achieving the effects of the present invention, calcium carbonate that has undergone surface treatment such as hydrophobic treatment may be used. Specifically, for example, stearic acid-treated calcium carbonate, rosin acid-treated calcium carbonate, lignin-treated calcium carbonate, fatty acid quaternary ammonium salt-treated calcium carbonate, etc. may be used.

[0058] The average particle size (average primary particle size) of calcium carbonate used in this rubber composition is, for example, 10 to 300 nm. From the viewpoint of significantly achieving the effects of the present invention, the average particle size (average primary particle size) of calcium carbonate is preferably, for example, 30 to 100 nm, and more preferably 30 to 70 nm. The average particle size (average primary particle size) can be calculated using a scanning transmission electron microscope.

[0059] Furthermore, the particle shapes of the calcium carbonate used in this rubber composition include, for example, cubic, spindle-shaped, disc-shaped, hexagonal plate-shaped, and spherical. Among these, the cubic shape is preferred from the viewpoint of further improving the damping characteristics. Examples of the cubic shape include regular hexahedrons and cube-shaped shapes that approximate regular hexahedrons. Specifically, for example, a hexahedron in which the difference in length of each piece is ±8 nm or less is an example.

[0060] The BET specific surface area of ​​calcium carbonate is not limited to the following, but for example, 4.0 to 60 m². 2 The value is / g, preferably 10 to 40m 2 / g, more preferably 20 to 35m 2 The value is / g. The BET specific surface area of ​​calcium carbonate can be measured, for example, by degassing the sample at 200°C for 15 minutes, and then using a BET specific surface area analyzer (Microdata Corporation, 4232-II) with a mixed gas (N2: 70%, He: 30%) as the adsorbed gas.

[0061] The amount of DBP (dioctyl phthalate) absorbed by calcium carbonate is not limited to the following, but is for example 15 to 75 cc / 100g, preferably 20 to 45 cc / 100g, and more preferably 20 to 30 cc / 100g.

[0062] From the viewpoint of easily controlling the number of aggregates within a suitable range, the calcium carbonate content is, for example, 15 to 100 parts by mass, preferably 25 to 80 parts by mass, more preferably 35 to 70 parts by mass, and even more preferably 40 to 60 parts by mass, based on 100 parts by mass of the total of components (A) and (B).

[0063] <Other Optional Components> In addition to components (A) to (C), this rubber composition may appropriately contain fillers such as silica and carbon black, processing aids, antioxidants, crosslinking agents, crosslinking accelerators, etc., to the extent that they do not hinder the effects of the present invention. These may be used alone or in combination of two or more. However, from the viewpoint of significantly achieving the effects of the present invention, it is preferable that this rubber composition does not contain crosslinking agents and crosslinking accelerators.

[0064] The total content of component (A) and component (B) in this rubber composition is not particularly limited, but is, for example, 30 to 70% by mass, preferably 40 to 68% by mass, and more preferably 45 to 65% by mass, based on the total amount of the rubber composition (100% by mass).

[0065] (Silica) As the silica, those conventionally known in the art can be appropriately used. Although not particularly limited, examples include wet silica, dry silica, colloidal silica, etc. These can be used alone or in combination of two or more.

[0066] Also, the surface of the above silica may be subjected to a hydrophobization treatment as necessary. As the hydrophobized silica, dimethylsilyl-treated silica and trimethylsilyl-treated silica surface-treated with dimethylsilane or trimethylsilane are preferable.

[0067] The BET specific surface area of the silica is not particularly limited. For example, it is preferably 350 m 2 / g or less, and preferably 80 - 320 m 2 / g, about 100 - 300 m 2 / g. The BET specific surface area of the silica can be measured, for example, by using a BET specific surface area measuring device (manufactured by Micro Data Co., 4232-II) with a mixed gas (N2: 70%, He: 30%) as the adsorbed gas after degassing the sample at 200°C for 15 minutes.

[0068] Also, the DBA adsorption amount of the silica is not particularly limited. For example, it is preferably 10 - 350 mmol / kg, and more preferably in the range of 20 - 300 mmol / kg. The DBA adsorption amount can be measured from the amount of dibutylamine (DBA) adsorbed on the unreacted silanol groups on the silica surface.

[0069] The content of the silica is not particularly limited. For example, it is preferably 20 - 80 parts by mass, and more preferably 30 - 60 parts by mass, based on 100 parts by mass in total of the components (A) and (B).

[0070] (Carbon Black) As the carbon black, those conventionally known in the art can be appropriately used. For example, various grades of carbon black such as SAF grade, ISAF grade, HAF grade, MAF grade, FEF grade, GPF grade, SRF grade, FT grade, MT grade, etc. can be mentioned. These can be used alone or in combination of two or more.

[0071] The specific surface area for nitrogen adsorption of carbon black is not particularly limited, but for example, it is 10 to 150 m². 2 A value of / g is preferred, and more preferably 15 to 100 m 2 / g, more preferably 20 to 76m 2 / g, particularly preferably 25 to 65m 2 The value is / g. The specific surface area of ​​nitrogen adsorption of carbon black can be measured, for example, by degassing the sample at 200°C for 15 minutes, and then using a mixed gas (N2: 70%, He: 30%) as the adsorbed gas, with a specific surface area measuring device (Microdata Corporation, 4232-II).

[0072] The amount of iodine adsorbed by carbon black is not particularly limited, but is preferably 10 to 150 mg / g, more preferably 10 to 75 mg / g, and even more preferably 20 to 65 mg / g. The amount of DBP (dibutyl phthalate) absorbed by carbon black is preferably 20 to 180 mL / 100 g, and more preferably 20 to 150 mL / 100 g. The iodine adsorbed amount of carbon black was measured in accordance with JIS K6217-1 (Method A), and the DBP absorbed amount of carbon black was measured in accordance with JIS K6217-4.

[0073] The carbon black content is not particularly limited, but is preferably 0.5 to 15 parts by mass, and more preferably 1 to 10 parts by mass, per 100 parts by mass of the total of components (A) and (B).

[0074] When silica and carbon black are used in combination, the content ratio of the two (silica:carbon black) is, for example, 98:2 to 70:30, and preferably 97:3 to 80:20.

[0075] (Anti-aging agents) Examples of anti-aging agents include aromatic secondary amine-based anti-aging agents, special wax-based anti-aging agents, amine-ketone-based anti-aging agents, phenol-based anti-aging agents, and imidazole-based anti-aging agents. These can be used alone or in combination of two or more. The content of the anti-aging agent is not particularly limited, but for example, it is 0.5 to 5 parts by mass, preferably 1 to 4 parts by mass, per 100 parts by mass of the total of components (A) and (B).

[0076] (Processing aids) Examples of processing aids include stearic acid, paraffin wax, polyethylene, and peptiders. The content of processing aids is not particularly limited, but is preferably 0.5 to 5 parts by mass, and 1 to 4.5 parts by mass, per 100 parts by mass of the total of components (A) and (B).

[0077] (Method for preparing this viscoelastic material) This viscoelastic material can be obtained by kneading components (A) to (C), and other components as needed, using a kneader, planetary mixer, mixing roll, twin-screw agitator, etc.

[0078] As described above, this vibration damping damper is characterized in that, in any 1 μm × 1 μm square region of a scanning transmission electron microscope image of a viscoelastic material taken at a magnification of 150,000, the number of aggregates, each consisting of three or more calcium carbonate particles, is in the range of 3 to 15. By controlling the number of such aggregates to be in the range of 3 to 15, excellent damping characteristics can be achieved.

[0079] The method for controlling the number of aggregates within the above range is not particularly limited, but examples include adjusting the temperature conditions when adding calcium carbonate in the kneading process of the materials when preparing the rubber composition, or adjusting the number of kneading cycles after adding calcium carbonate, within a certain range.

[0080] Among these methods, the method of adjusting the temperature conditions when adding calcium carbonate during the mixing process of the materials within a certain range is preferred. Specifically, for example, it is preferable to adjust the temperature when adding calcium carbonate (temperature of the kneaded material) within the range of 50 to 110°C by adjusting the rotation speed of the kneading equipment such as a kneader or the temperature control of the kneader. For example, it is preferable to adjust the temperature of the kneaded material containing at least components (A) and (B) to the range of 50 to 110°C, and then add calcium carbonate (C) to the kneaded material and knead it. If calcium carbonate (C) is added under conditions of a temperature lower than the aforementioned temperature range, the number of aggregates tends to be less than the range defined in this invention, and the decay characteristics tend to be insufficient. Conversely, if calcium carbonate (C) is added under conditions of a temperature higher than the aforementioned temperature range, the number of aggregates tends to be more than the range defined in this invention, and the decay characteristics tend to be insufficient.

[0081] More specifically, although not limited to the following, a manufacturing method comprising a first step of kneading at least component (A) and component (B) to prepare a first kneaded product, and a second step of adding and kneading calcium carbonate or the like to the first kneaded product to obtain a second kneaded product, wherein the first step is kneaded at 80 to 150°C for 3 to 15 minutes (preferably 100 to 120°C for 7 to 12 minutes), and the second step is to add calcium carbonate (C) to the kneaded product obtained in the first step under conditions of adjusting the temperature to the range of 50 to 110°C, knead for 2 to 10 minutes (preferably 3 to 8 minutes), and then knead at 80 to 150°C for 3 to 15 minutes (preferably 100 to 120°C for 7 to 12 minutes), is suitable as a manufacturing method for controlling the number of aggregates within the above range.

[0082] The temperature conditions (temperature of the mixture) when adding the calcium carbonate can be appropriately adjusted within the range of 50 to 110°C, for example, within the range of 60 to 100°C or 70 to 90°C. By kneading under such low-temperature conditions, mechanical shear force can be effectively applied, and the dispersion form of the calcium carbonate can be effectively controlled.

[0083] Furthermore, a preferred embodiment of the first step may be a first step of preparing a first kneaded product by kneading at least component (A), component (B), and filler (excluding component (C)), and more specifically, a first step of preparing a first kneaded product by kneading at least component (A), component (B), and silica.

[0084] (Method for manufacturing vibration damping dampers) As a method for manufacturing vibration damping dampers, for example, a rubber composition (viscoelastic material) is prepared as described above, and several metal plates of a predetermined size are prepared. The rubber composition (viscoelastic material) is layered on the metal plates, and finally, another metal plate is placed on top to create a laminate. Adhesive is applied to the laminated surface of the metal plates in advance.

[0085] Here, Figure 1 shows an example of this vibration damping damper. In the figure, 1 is the vibration damping damper, 2 is the viscoelastic body (viscoelastic layer), and 4 and 5 are metal plates (metal layers). The viscoelastic body (viscoelastic layer) is sandwiched between two metal plates 4 and 5 and bonded to the two metal plates 4 and 5 with an adhesive. Figure 2 is a cross-sectional view (A-A' cross-section in Figure 1) showing an example of this vibration damping damper. In Figure 2, the viscoelastic body 2 in the vibration damping damper has a single-layer structure. Although not shown, in this vibration damping damper, an adhesive (adhesive layer) is applied and interposed at the interface between the viscoelastic body 2 (viscoelastic layer) and the metal plate 4 (metal layer), and an adhesive (adhesive layer) is also applied and interposed at the interface between the viscoelastic body 2 (viscoelastic layer) and the metal plate 5 (metal layer). Figure 3 is a cross-sectional view showing another example of the vibration damping damper. In Figure 3, the viscoelastic body 2 in the vibration damping damper has a two-layer structure. Although not shown in the diagram, in this vibration damping damper, an adhesive (adhesive layer) is applied and interposed at the interface between the viscoelastic body 2 (viscoelastic layer) and the metal plate 4 (metal layer), and an adhesive (adhesive layer) is also applied and interposed at the interface between the viscoelastic body 2 (viscoelastic layer) and the metal plate 5 (metal layer).

[0086] Figure 4 shows an example of the installation of the vibration damping damper 1. In Figure 4, 1 is the vibration damping damper, 2 is the viscoelastic body, 4 and 5 are metal plates, 6 is a bolt, 7 and 8 are panels, 10 is a beam, and 11 is a foundation. As shown in the figure, the metal plates 4 and 5 of the vibration damping damper 1 are attached to panels 7 and 8, respectively, by bolts 6. The viscoelastic body 2 sandwiched between the metal plates 4 and 5 functions to dampen vibrations between the beam 10 and the foundation 11.

[0087] The vibration damper of the present invention is not limited to the shape described above, and can exhibit excellent functionality as a vibration damper (also called a seismic damper) for civil engineering and construction, as well as for home appliances and electronic devices. In particular, it can exhibit even better functionality as a vibration damper (also called a seismic damper) used in large structures such as bridges and buildings, and especially as a vibration damper for high-rise buildings.

[0088] Next, examples will be described together with comparative examples. However, the present invention is not limited to these examples unless it exceeds the essence of the invention.

[0089] (Example 1) The target rubber composition was prepared by blending each component shown in Table 1 in the proportions shown in the same table. Specifically, the rubber composition was prepared through a first step of kneading components (A) and (B) to prepare a masterbatch, and a second step of adding the remaining materials to the masterbatch and kneading. The first step was performed by kneading at 130°C for 10 minutes using a kneader. The second step was performed by adjusting the temperature of the masterbatch prepared in the first step to 80°C using a kneader, adding calcium carbonate and kneading for 3 minutes, then adding the remaining materials and kneading at 130°C for 10 minutes.

[0090] (Example 2) The rubber composition of Example 2 was obtained in the same manner as in Example 1, except that the temperature conditions when calcium carbonate was added (masterbatch temperature) were changed to 60°C.

[0091] (Example 3) The rubber composition of Example 3 was obtained in the same manner as in Example 1, except that the temperature conditions when calcium carbonate was added (masterbatch temperature) were changed to 100°C.

[0092] (Comparative Example 1) A rubber composition of Comparative Example 1 was obtained in the same manner as in Example 1, except that the temperature conditions when calcium carbonate was added (masterbatch temperature) were changed to 120°C.

[0093] (Comparative Example 2) A rubber composition of Comparative Example 2 was obtained in the same manner as in Example 1, except that the temperature conditions when calcium carbonate was added (masterbatch temperature) were changed to 45°C.

[0094] [Measurement of the number of aggregates consisting of three or more calcium carbonate particles] Using a microtome (Leica, EM UC7), smooth surfaces were prepared of the rubber compositions (viscoelastic materials) of the examples and comparative examples. Using a scanning transmission electron microscope (JEOL, JEM-2800), scanning transmission electron microscope images of the rubber compositions (viscoelastic materials) were acquired at a magnification of 150,000x at four locations. The number of aggregates in a 1 μm × 1 μm area of ​​the obtained images was visually measured. The average value of the number of aggregates measured at the four locations (rounded to the nearest whole number) was calculated. The results are shown in Table 1. (Image acquisition conditions) Magnification: 150,000x Sample thickness: 80 nm Acceleration voltage: 200 kV Probe size: 1 nm Image size (pixels): 512 × 512 Observation mode: STEM-DF (dark-field imaging)

[0095] Specifically, first, a scanning transmission electron microscope image is acquired as described above. Next, an elemental mapping image is acquired using an energy-dispersive X-ray spectrometer (JEM-2800 / SDD100GV, manufactured by JEOL Ltd.) attached to the scanning transmission electron microscope, and calcium carbonate is identified in the microscope image by detecting Ca atoms derived from calcium carbonate. Then, the elemental mapping image and a magnified image of the microscope image (a 1 μm × 1 μm area) are compared, and the number of aggregates consisting of three or more calcium carbonate particles is visually measured. The results are shown in Table 1.

[0096] Let's explain this in more detail using Example 1 as an example. Figure 7 shows a scanning transmission electron microscope image of Example 1 (magnification 150,000x), Figure 8 shows an elemental mapping image of Example 1, and Figure 9 shows a magnified view of the scanning transmission electron microscope image (1 μm × 1 μm area). The elemental mapping image in Figure 7 and the magnified view of the scanning transmission electron microscope image (1 μm × 1 μm area) in Figure 9 are visually compared, and the number of aggregates in the scanning transmission electron microscope image is measured. In Figure 9, aggregates consisting of three or more connected calcium carbonate particles are indicated by circular frames, and the dispersion morphology shows seven aggregates consisting of three or more connected calcium carbonate particles. In each example, the aggregates consisted of 3 to 10 connected calcium carbonate particles.

[0097] Furthermore, when measuring the number of aggregates, it is preferable to select at least four regions of an image with an arbitrary size of 1 μm × 1 μm, observe the dispersion pattern of calcium carbonate particles in each region, measure the number of aggregates, and calculate the average value of the number of aggregates in the four regions.

[0098] [Damping Characteristics Test] The damping characteristics of the rubber composition were evaluated using the apparatus shown in Figure 5. Specifically, a two-component adhesive for rubber was applied to predetermined locations (adhesion locations for sample 21) of two blast-treated metal fittings 22 (size 140 mm x 80 mm, thickness 9 mm). Then, the rubber composition of the example or comparative example was sandwiched between the two metal fittings 22 and dried. This was then hot-pressed at 100°C for 10 minutes to produce a sample (size 70 mm x 80 mm, thickness 5 mm) 21. The apparatus was then vibrated in the direction of the arrow, and the dynamic shear characteristics were evaluated based on the load-strain loop curve shown in Figure 6. Specifically, the above apparatus was subjected to vibration excitation simulating a major earthquake (shear strain rate: 200% (200% of sample thickness), frequency (f): 0.33 Hz, measurement temperature: 20°C) using a vibration exciter (Washinomiya Seisakusho Co., Ltd., DYNAMIC SERVO), an input signal oscillator (Yokogawa Electric Corporation, Synthesized Function Generator FC320), and an output signal processor (Ono Sokki Co., Ltd., Portable FFT Analyzer CF-3200). From the analysis of the shear strain value (δ) and load value (Qd) with respect to the excitation time, the equivalent stiffness (Ke) and equivalent damping coefficient (Ce) were determined according to the following equations (1) to (3), and the damping constant (he) was determined from these values. In the following equations, ω = 2πf and W = Keδ 2 / 2, ΔW represents the load-strain loop area (absorbed energy). Equivalent stiffness: Ke (N / mm) = Qd / δ …(1) Equivalent damping coefficient: Ce (kN・s / m) = ΔW / πωδ 2 …(2) Damping constant: he = ΔW / 4πW …(3)

[0099] The attenuation constant in Comparative Example 1 was set to 1.0 (reference), and the exponential values ​​of the attenuation constants in each example and comparative example were calculated and evaluated according to the following criteria. The results are shown in Table 1. (Evaluation Criteria) ◎ (very good) ... Attenuation constant (exponential value) is 1.20 or higher 〇 (good) ... Attenuation constant (exponential value) is 1.05 or higher and less than 1.20 × (poor) ... Attenuation constant (exponential value) is less than 1.05

[0100]

[0101] From the results in Table 1 above, it can be seen that the sample of the example satisfies the requirements of the present invention and therefore exhibits excellent decay characteristics. Specifically, it can be seen that the excellent decay characteristics are due to the fact that the number of aggregates, each consisting of three or more calcium carbonate particles, is within a specific range of 3 to 15.

[0102] In contrast, the results in Table 1 above show that the comparative examples do not satisfy the requirements of the present invention and therefore have insufficient damping characteristics. Specifically, Comparative Example 1, which had 20 aggregates of three or more calcium carbonate particles, exhibited inferior damping characteristics. Similarly, Comparative Example 2, which had 2 aggregates of three or more calcium carbonate particles, also exhibited inferior damping characteristics.

[0103] Based on the above, it can be seen that the requirements of the present invention are met, namely, a vibration damping damper having a viscoelastic body made of a rubber composition containing components (A) to (C) as a constituent member, and that the number of aggregates of three or more calcium carbonate particles in any 1 μm × 1 μm square region of a scanning transmission electron microscope image of the viscoelastic body taken at a magnification of 150,000 is in the range of 3 to 15, and that the damping characteristics are excellent.

[0104] While the above embodiments illustrate specific forms of the present invention, these embodiments are merely illustrative and should not be interpreted restrictively. Various modifications that are obvious to those skilled in the art are intended to fall within the scope of the present invention.

[0105] The vibration damper of the present invention can exhibit excellent functionality as a vibration damper for civil engineering, construction, home appliances, and electronic devices. In particular, it can exhibit even better functionality as a vibration damper used in large structures such as bridges and buildings, and especially as a vibration damper for high-rise buildings. Furthermore, vibration damping devices and seismic isolation devices such as vibration damping walls for buildings, vibration damping materials and shock absorbers for home appliances and electronic devices, and vibration damping materials and shock absorbers for automobiles, which are equipped with the viscoelastic material that is a component of the vibration damper of the present invention, can also be used as vibration dampers of the present invention.

[0106] 1. Vibration damper 2. Viscoelastic material 4, 5. Metal plate 6. Bolt 7, 8. Panel 10. Beam 11. Foundation

Claims

1. A vibration damping damper comprising a viscoelastic body made of a rubber composition containing the following components (A) to (C), wherein the number of aggregates of three or more calcium carbonate particles in any 1 μm × 1 μm square region of a scanning transmission electron microscope image of the viscoelastic body taken at a magnification of 150,000 is in the range of 3 to 15. (A) At least one of styrene-isoprene-styrene copolymer and styrene-butadiene-styrene copolymer (B) One or more selected from the group consisting of ethylene-propylene-diene terpolymer, ethylene-butene-diene terpolymer, and butadiene rubber (C) Calcium carbonate 2. The vibration damping damper according to claim 1, wherein the number of aggregates of three or more calcium carbonate particles is in the range of 5 to 9.

3. The vibration damping damper according to claim 1 or 2, wherein the amount of calcium carbonate is 15 to 100 parts by mass per 100 parts by mass of the total of components (A) and (B).

4. The vibration damping damper according to any one of claims 1 to 3, wherein the particle shape of the calcium carbonate is cubic.

5. The vibration damping damper according to any one of claims 1 to 4, wherein the average particle size of the calcium carbonate is 10 to 300 nm.

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