JP5568581B2 - High damping composition and viscoelastic damper - Google Patents

Description

  The present invention relates to a high-damping member for relaxing or absorbing the transmission of vibration energy, a high-damping composition as a basis thereof, and a viscoelasticity formed using the high-damping composition as a forming material. The present invention relates to a viscoelastic damper of a building including a body.

For example, high-attenuation members are used in a wide range of fields such as buildings such as buildings and bridges, industrial machines, airplanes, automobiles, railway vehicles, computers and peripheral equipment, household electrical equipment, and automobile tires. By using the high damping member, transmission of vibration energy can be relaxed or absorbed, that is, seismic isolation, vibration control, vibration control, vibration isolation, etc. can be performed.
The high attenuation member is formed of a high attenuation composition containing natural rubber or the like as a base polymer. The high damping composition has an inorganic filling such as carbon black, silica, etc. in order to increase the hysteresis loss when vibration is applied and to attenuate the vibration energy efficiently and quickly, that is, to increase the damping performance. In general, a tackifier such as a rosin or a petroleum resin is blended (see, for example, Patent Documents 1 to 3).

However, these conventional high damping compositions cannot sufficiently enhance the damping performance of the high damping member. In order to further improve the damping performance of the high damping member, it is conceivable to further increase the blending ratio of an inorganic filler, a tackifier, or the like.
However, the high attenuation composition containing a large amount of an inorganic filler or a tackifier increases the viscosity, decreases the workability, and the high attenuation composition in order to produce a high attenuation member having a desired three-dimensional shape. There is a problem that it is not easy to knead an object or to mold it into the three-dimensional shape.

Particularly when mass-producing high-attenuation members at the factory level, the low workability is desirable because it greatly reduces the productivity of high-attenuation members, increases the energy required for production, and further increases production costs. Absent.
Therefore, in order to improve the damping performance without degrading workability, Patent Document 4 discusses blending silica and a tackifier having two or more polar groups.

However, a base polymer having a polar group in the molecule, such as one having the polar side chain, generally has a glass transition temperature Tg near room temperature (3-35 ° C.). A high damping member formed using an object tends to have a large temperature dependency of characteristics such as rigidity in the vicinity of the room temperature, which is the most common operating temperature range.
In Patent Document 5, it is studied to add silica and a tackifier having two or more polar groups to a base polymer having no polar side chain. According to such a configuration, it is possible to reduce the temperature dependence of characteristics near room temperature by using a base polymer that does not have a polar group while maintaining good attenuation performance by using silica together. .

However, when the mixing ratio of the tackifier is increased in order to further improve the damping performance than the current situation, the tackifier blooms on the surface of the high attenuation member, and the high attenuation member There is concern about poor adhesion with metals and the like.
Moreover, the adhesiveness at the time of kneading | mixing becomes high too much, and workability falls.
Patent Document 6 discusses further improving the damping performance by using a rosin derivative having a specific softening point as a tackifier.

  However, when the blending ratio of the rosin derivative is increased in order to further improve the damping performance as compared with the current situation, the adhesiveness at the time of kneading becomes too high and the workability is lowered.

Japanese Patent No. 3523613 JP 2007-63425 A Japanese Patent No. 2796044 Japanese Patent No. 3664211 JP 2009-138053 A JP 2010-189604 A

  An object of the present invention is to provide a highly attenuating composition that is capable of forming a highly attenuating member that is excellent in damping performance and that is also excellent in workability, and a viscoelastic body that is formed using the highly attenuating composition as a forming material. It is to provide a viscoelastic damper for a building.

In the present invention, the base polymer is surface-treated with a silane coupling agent on the outermost surface of 100 parts by mass or more and 180 parts by mass or less of silica and 1 part by mass or more and 30 parts by mass or less per 100 parts by mass of the base polymer . A highly attenuated composition comprising a modified calcium carbonate.
Calcium carbonate functions as an inorganic filler that improves the damping performance of the high damping member, like silica and the like, and can improve the damping performance of the high damping member. Therefore, it is expected to improve the processability of the highly attenuated composition.

  However, the untreated calcium carbonate or the surface-treated calcium carbonate obtained by surface-treating the surface of the untreated calcium carbonate with rosin acid or fatty acid does not have a high interaction with the base polymer. Therefore, the high-damping composition containing calcium carbonate has a low green strength immediately after kneading, and when it is taken out from the kneader, for example, it is immediately cut even when pulled by hand, and the entire amount is taken out from the kneader. It is easy to cause a problem that it takes time and effort. Therefore, although kneading and forming after kneading are easy, the effect of improving workability is not yet sufficient.

On the other hand, the modified calcium carbonate obtained by surface-treating the outermost surface of calcium carbonate with a silane coupling agent is superior in interaction with a base polymer and the like compared to the untreated calcium carbonate and surface-treated calcium carbonate. The high-damping composition functions to increase the green strength immediately after kneading. Therefore, when taking out the high attenuation composition from the kneading machine, it is not easily cut even if it is pulled by hand, and the work of taking out the entire amount from the kneading machine is saved, thereby further improving the workability of the high attenuation composition. It becomes possible to do.

However, when the blending ratio of the modified calcium carbonate is less than the above range, these effects cannot be obtained by selecting and blending the modified calcium carbonate. On the other hand, when the above range is exceeded, there is a problem that durability when the high attenuation member is repeatedly largely deformed is deteriorated and the high attenuation member is damaged.
On the other hand, by making the blending ratio of the modified calcium carbonate within the above range, the durability when repeatedly repeatedly deforming the high attenuation member is improved while maintaining good processability of the high attenuation composition. Can do.

Moreover, if the mixing ratio of silica is less than the above range, good damping performance cannot be imparted to the high damping member. On the other hand, when the above range is exceeded, there is a problem that durability when the high attenuation member is repeatedly largely deformed is deteriorated and the high attenuation member is damaged.
On the other hand, by setting the blending ratio of silica within the above range, it is possible to improve the durability when repeatedly deforming the high attenuation member repeatedly while giving the high attenuation member the best possible attenuation performance. .

The viscoelastic damper of the present invention includes a viscoelastic body formed using the high damping composition of the present invention as a forming material. Such viscoelastic dampers are excellent in damping performance, so that they can be downsized and the number incorporated in one building can be reduced.

According to the present invention, it is possible to form a highly-damping member having excellent damping performance, and to provide a highly-damping composition having excellent workability and a viscoelastic body formed using the high-damping composition as a forming material. , a viscoelastic dampers of the building can be provided and the child is.

It is a disassembled perspective view which decomposes | disassembles and shows the test body as a model of the said high attenuation member produced in order to evaluate the attenuation performance of the high attenuation member which consists of the high attenuation composition of the Example of this invention, and a comparative example. FIGS. 4A and 4B are diagrams for explaining the outline of a testing machine for displacing the test body and obtaining the relationship between the displacement and the load. It is a graph which shows an example of the hysteresis loop which shows the relationship between the displacement amount and a load calculated | required by displacing a test body using the said testing machine.

<High damping composition>
In the highly attenuated composition of the present invention, 100 parts by mass or more and 180 parts by mass or less of silica and 1 part by mass or more and 30 parts by mass or less of modified calcium carbonate are blended with 100 parts by mass of the base polymer. It is characterized by this.
(Base polymer)
As the base polymer, any conventionally known various polymers that can function as the base polymer of the high damping member can be used, and diene rubber is particularly preferable.

Since such a diene rubber does not have a glass transition temperature near room temperature (2 to 35 ° C.), temperature dependency such as rigidity of a high damping member near the room temperature, which is the most general use temperature range, is reduced. Thus, there is an advantage that a high attenuation member that exhibits stable characteristics over a wide temperature range can be formed.
Examples of the diene rubber include one or more of natural rubber, isoprene rubber, butadiene rubber, styrene butadiene rubber, and the like. Considering the availability of materials, etc., natural rubber is preferably used as the diene rubber.

(silica)
As the silica, any of wet process silica and dry process silica classified by the production method may be used. In consideration of further improving the effect of improving the damping performance of the high damping member, it is preferable to use silica having a BET specific surface area of 100 to 400 m ² / g, particularly 200 to 250 m ² / g. . The BET specific surface area is expressed by a value measured by a gas phase adsorption method using nitrogen gas as an adsorbed gas, for example, using a rapid surface area measuring device SA-1000 manufactured by Shibata Chemical Instruments Co., Ltd.

Examples of the silica include NipSil (nip seal) KQ manufactured by Tosoh Silica Co., Ltd.
The blending ratio of the silica is limited to 100 parts by mass or more and 180 parts by mass or less per 100 parts by mass of the base polymer.
When the blending ratio of silica is less than the above range, good damping performance cannot be imparted to the high damping member. On the other hand, when the above range is exceeded, there is a problem that durability when the high attenuation member is repeatedly largely deformed is deteriorated and the high attenuation member is damaged.

On the other hand, by setting the blending ratio of silica within the above range, it is possible to improve the durability when repeatedly deforming the high attenuation member repeatedly while giving the high attenuation member the best possible attenuation performance. .
(Modified calcium carbonate)
Examples of the modified calcium carbonate include untreated calcium carbonate such as synthetic calcium carbonate and heavy calcium carbonate, or the untreated calcium carbonate such as fatty acid, quaternary ammonium salt, rosin acid, lignic acid, silica hydrosol. Any of various modified calcium carbonates obtained by further modifying the outermost surface of the surface-treated calcium carbonate or the like that has been surface-treated with one or more of the above by a silane coupling agent can be used.

The primary particle diameter of the modified calcium carbonate is preferably 5 nm or more, particularly preferably 15 nm or more, and is preferably 100 nm or less, particularly 90 nm or less in consideration of imparting as good damping performance as possible to the high attenuation member. preferable.
Wherein the modified carbon calcium surface-treated uppermost surface with a silane coupling agent is particularly excellent in the interaction with the base polymer or the like, with a small amount of formulation to impart good damping performance in high damping member Can do. In addition, the adhesiveness during kneading is not increased, and the high damping composition is also excellent in increasing the green strength immediately after kneading. Therefore, when taking out the high attenuation composition from the kneader, it can be easily cut even if it is pulled by hand, and the work of taking out the entire amount from the kneader can be saved. It is possible to further improve the performance.

As a specific example of the modified calcium carbonate, for example, the surface of synthetic calcium carbonate having a primary particle diameter of about 20 nm is surface-treated with silica hydrosol and fatty acids, and then the outermost surface is surface-treated with a silane coupling agent. ACTIFORT (registered trademark) 700 manufactured by Shiraishi Kogyo Co., Ltd.
The blending ratio of the modified calcium carbonate needs to be 1 part by mass or more and 30 parts by mass or less per 100 parts by mass of the base polymer.

  When the blending ratio of the modified calcium carbonate is less than the above range, not only the effect of improving the damping performance of the high damping member is not obtained, but also the effect of suppressing the adhesiveness of the high damping composition at the time of kneading cannot be obtained. For example, there is a problem that it takes time to take out the highly attenuated composition after kneading from the kneader. On the other hand, when the above range is exceeded, there is a problem that durability when the high attenuation member is repeatedly largely deformed is deteriorated and the high attenuation member is damaged.

On the other hand, by making the blending ratio of the modified calcium carbonate within the above range, the durability when repeatedly repeatedly deforming the high attenuation member is improved while maintaining good processability of the high attenuation composition. Can do.
(Other ingredients)
In the high attenuation composition of the present invention, an inorganic filler other than the silica and modified calcium carbonate, or a crosslinking component for crosslinking a base polymer such as a diene rubber is blended at an appropriate ratio. Also good.

Examples of the other inorganic fillers include carbon black.
As the carbon black, one or more of carbon blacks that can function as a filler among various carbon blacks classified according to the production method thereof can be used.
The mixing ratio of carbon black is not particularly limited, but is preferably 1 part by mass or more and 5 parts by mass or less per 100 parts by mass of the base polymer.

  As the crosslinking component, various crosslinking components capable of crosslinking the base polymer can be used. When the base polymer is a diene rubber, it is particularly preferable to use a sulfur vulcanized crosslinking component. Examples of the sulfur-vulcanized crosslinking component include a combination of a vulcanizing agent, a vulcanization accelerator, and a vulcanization acceleration aid. In particular, it is preferable to combine a vulcanizing agent, a vulcanization accelerator, and a vulcanization acceleration aid that hardly cause the problem that the rubber elasticity of the high damping member increases and the damping performance decreases.

Examples of the vulcanizing agent include sulfur and sulfur-containing organic compounds. In particular, sulfur is preferable.
Examples of the vulcanization accelerator include a sulfenamide vulcanization accelerator and a thiuram vulcanization accelerator. It is preferable to use two or more vulcanization accelerators in combination because the vulcanization acceleration mechanism varies depending on the type.

Among them, examples of the sulfenamide-based vulcanization accelerator include Noxeller (registered trademark) NS [N-tert-butyl-2-benzothiazolylsulfenamide] manufactured by Ouchi Shinsei Chemical Industry Co., Ltd. . Examples of the thiuram vulcanization accelerator include Noxeller TBT [tetrabutyl thiuram disulfide] manufactured by Ouchi Shinsei Chemical Co., Ltd.
Examples of the vulcanization acceleration aid include zinc white and stearic acid. Usually, it is preferable to use both as a vulcanization acceleration aid.

The blending ratio of the vulcanizing agent, the vulcanization accelerator, and the vulcanization accelerating agent may be appropriately adjusted according to the characteristics such as the damping performance and the rigidity that differ depending on the use of the high damping member.
In the high attenuation composition of the present invention, various additives such as a silane compound, a softening agent, a tackifier, and an anti-aging agent may be further blended at an appropriate ratio as necessary.
Among these, as the silane compound, the formula (a):

[Wherein, at least one of R ¹ , R ² , R ³ , and R ⁴ represents an alkoxy group. However, R ¹ , R ² , R ³ , and R ⁴ are not simultaneously an alkoxy group, and the other represents an alkyl group or an aryl group. ]
And various silane compounds that can function as a silica dispersant, such as a silane coupling agent and a silylating agent.

In particular, alkoxysilanes such as hexyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, and diphenyldimethoxysilane are preferred.
Examples of the silane compound include KBE-103 (phenyltriethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd.
The blending ratio of the silane compound is not particularly limited, but it is preferably 5 parts by mass or more and preferably 25 parts by mass or less per 100 parts by mass of silica.

The softening agent is a component for further improving the workability of the highly attenuated composition, and examples of the softening agent include liquid rubber that exhibits a liquid state at room temperature (2 to 35 ° C.). Examples of the liquid rubber include one or more of liquid polyisoprene rubber, liquid nitrile rubber (liquid NBR), liquid styrene butadiene rubber (liquid SBR), and the like.
Of these, liquid polyisoprene rubber is preferred. Examples of the liquid polyisoprene rubber include Kuraray (trademark) LIR-30 (number average molecular weight: 28000), LIR-50 (number average molecular weight: 54000) manufactured by Kuraray Co., Ltd., and the like.

The blending ratio of the liquid polyisoprene rubber is preferably 5 parts by mass or more per 100 parts by mass of the base polymer, and is preferably 50 parts by mass or less.
If the blending ratio is less than the above range, the effect of lowering the rigidity of the high damping member by blending the liquid polyisoprene rubber may not be sufficiently obtained. On the other hand, if the above range is exceeded, the damping performance of the high damping member may be reduced.

Examples of other softening agents include coumarone indene resin.
Examples of the coumarone indene resin include various coumarone indene resins which are mainly composed of a polymer of coumarone and indene and have a relatively low molecular weight of about 1000 or less in average molecular weight and can function as a softening agent.
As the coumarone indene resin, for example, Knit Resin (registered trademark) Coumarone G-90 manufactured by Nikko Chemical Co., Ltd. [average molecular weight: 770, softening point: 90 ° C., acid value: 1.0 KOH mg / g or less, hydroxyl group] Value: 25 KOH mg / g, bromine value 9 g / 100 g], G-100N [average molecular weight: 730, softening point: 100 ° C., acid value: 1.0 KOH mg / g or less, hydroxyl value: 25 KOH mg / g, bromine value 11 g / 100 g V-120 [average molecular weight: 960, softening point: 120 ° C., acid value: 1.0 KOH mg / g or less, hydroxyl value: 30 KOH mg / g, bromine value 6 g / 100 g], V-120S [average molecular weight: 950, Softening point: 120 ° C., acid value: 1.0 KOH mg / g or less, hydroxyl value: 30 KOH mg / g, bromine value 7 g / 100 g] and the like.

The blending ratio of the coumarone indene resin is not particularly limited, but it is preferably 5 parts by mass or more and preferably 20 parts by mass or less per 100 parts by mass of the base polymer.
Examples of the tackifier include petroleum resins. As the petroleum resin, for example, Marcaretz (registered trademark) M890A [dicyclopentadiene-based petroleum resin, softening point: 105 ° C.] manufactured by Maruzen Petrochemical Co., Ltd. is preferable.

The blending ratio of the petroleum resin is not particularly limited, but it is preferably 3 parts by mass or more and preferably 30 parts by mass or less per 100 parts by mass of the base polymer.
As an anti-aging agent, 1 type, or 2 or more types of various anti-aging agents, such as a benzimidazole type, a quinone type, a polyphenol type, and an amine type, are mentioned, for example. In particular, it is preferable to use a benzimidazole antioxidant and a quinone antioxidant together.

Among them, examples of the benzimidazole-based anti-aging agent include NOCRACK (registered trademark) MB [2-mercaptobenzimidazole] manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Examples of the quinone anti-aging agent include Antigen FR [aromatic ketone-amine condensate] manufactured by Cobblestone Chemical Co., Ltd.
The blending ratio of both anti-aging agents is not particularly limited, but the benzimidazole anti-aging agent is preferably 0.5 parts by mass or more and preferably 5 parts by mass or less per 100 parts by mass of the base polymer. The quinone anti-aging agent is preferably 0.5 parts by mass or more and preferably 5 parts by mass or less per 100 parts by mass of the base polymer.

  The high damping member that can be manufactured using the high damping composition of the present invention includes, for example, a seismic isolation damper that is incorporated in the foundation of a building such as a building, and a vibration control (vibration suppression) that is incorporated in the structure of a building Viscoelastic dampers, vibration control members for cables such as suspension bridges and cable-stayed bridges, vibration control members for industrial machines, aircraft, automobiles, railway vehicles, etc., vibration control members for computers, peripheral equipment, and household electrical equipment Furthermore, treads for automobile tires and the like can be mentioned.

According to the present invention, the base polymer, silica, modified calcium carbonate, and other various kinds of components, and combinations and blending ratios thereof are adjusted to provide a high damping member having excellent damping performance suitable for each application. Can be obtained.
<Viscoelastic damper>
In particular, when the viscoelastic body of a viscoelastic damper of a building as a high damping member is formed using the high damping composition of the present invention as a forming material, the viscoelastic body has high damping performance. Even if the damping performance of a viscoelastic damper including a viscoelastic body is improved and the whole is downsized or the number incorporated in one building is reduced, the vibration control performance equivalent to or higher than that of the conventional one can be obtained. Can do.

  In addition, when diene rubber is used as the base polymer, the temperature dependence of the viscoelastic body such as rigidity can be reduced. For example, the viscoelastic damper is grounded near the outer wall of a building having a large temperature difference. It is also possible to increase the degree of freedom in designing the vibration control performance by the viscoelastic damper.

<Example 1>
(Preparation of highly attenuated composition)
100 parts by mass of natural rubber (SMR (Standard Malaysian Rubber) -CV60) as a base polymer, 135 parts by mass of silica (NipSil (nip seal) KQ made by Tosoh Silica Co., Ltd.), and modified calcium carbonate [see above ACTIFORT (registered trademark) 700 manufactured by Shiraishi Kogyo Co., Ltd., surface of synthetic calcium carbonate having a primary particle size of about 20 nm is treated with silica hydrosol and fatty acids, and the outermost surface is further treated with a silane cup. The surface treated with a ring agent] 1 part by mass and each component shown in Table 1 below were blended and kneaded using a closed kneader to prepare a highly attenuated composition. In addition, the mass part in Table 1 is a mass part per 100 mass parts of natural rubber as a base polymer, respectively.

Each component in the table is as follows.
Silane compound: Phenyltriethoxysilane, KBE-103 manufactured by Shin-Etsu Chemical Co., Ltd.
Liquid polyisoprene rubber: LIR-50 manufactured by Kuraray Co., Ltd., number average molecular weight: 54000
Carbon Black: Dia Black (registered trademark) G manufactured by Mitsubishi Chemical Corporation
Benzimidazole anti-aging agent: 2-mercaptobenzimidazole, NOCRACK MB manufactured by Ouchi Shinsei Chemical Co., Ltd.
Quinone anti-aging agent: Antigen FR manufactured by Maruishi Chemical Co., Ltd.
Two types of zinc oxide: manufactured by Mitsui Mining & Smelting Co., Ltd. Stearic acid: "Tsubaki" manufactured by NOF Corporation
Dicyclopentadiene-based petroleum resin: softening point 105 ° C., Marukaretsu (registered trademark) M890A manufactured by Maruzen Petrochemical Co., Ltd.
Coumarone resin: softening point 90 ° C., Nikko Chemical Co., Ltd. Escron (registered trademark) G-90
5% oil-treated powder sulfur: vulcanizing agent, manufactured by Tsurumi Chemical Industry Co., Ltd. Sulfenamide vulcanization accelerator: N-tert-butyl-2-benzothiazolylsulfenamide, Ouchi Shinsei Chemical Industry Co., Ltd. Noxeller (registered trademark) NS
Thiuram-based vulcanization accelerator: Tetrabutylthiuram disulfide, Noxeller TBT-N manufactured by Ouchi Shinsei Chemical Co., Ltd.
<Comparative example 1>
A highly attenuated composition was prepared in the same manner as in Example 1 except that the modified calcium carbonate was not blended.

<Examples 2 and 3, Comparative Examples 2 and 3>
The blending ratio of the modified calcium carbonate is 0.5 parts by mass (Comparative Example 2), 15 parts by mass (Example 2), 30 parts by mass (Example 3), and 35 parts per 100 parts by mass of the natural rubber as the base polymer. A highly attenuating composition was prepared in the same manner as in Example 1 except that it was changed to part by mass (Comparative Example 3).

<Comparative example 4>
In place of the modified calcium carbonate, 15 parts by mass of surface-treated calcium carbonate [Shiraishi Hana (registered trademark) CC, primary particle size 50 nm, manufactured by Shiroishi Kogyo Co., Ltd.], which is a surface treatment of synthetic calcium carbonate with a fatty acid, was added. A highly attenuated composition was prepared in the same manner as in Example 1 except that.
<Attenuation characteristic test>
(Preparation of test specimen)
The high attenuation compositions prepared in Examples and Comparative Examples were extruded into a sheet shape and then punched to produce a disk 1 (thickness 5 mm × diameter 25 mm) as shown in FIG. Further, a highly attenuating composition in which a rectangular plate-shaped steel plate 2 having a thickness of 6 mm, a length of 44 mm, and a width of 44 mm is stacked on each other through a vulcanizing adhesive and heated to 150 ° C. while pressing in the laminating direction to form the disk 1. , And the disk 1 was vulcanized and bonded to the two steel plates 2 to produce a specimen 3 for evaluating damping characteristics as a model of a high damping member.

(Displacement test)
As shown in FIG. 2 (a), two test bodies 3 are prepared, and the two test bodies 3 are fixed to one central fixing jig 4 with bolts via one steel plate 2. One left and right fixing jig 5 was fixed to the other steel plate 2 of each test body 3 with bolts. The center fixing jig 4 is fixed to the upper fixing arm 6 of the testing machine (not shown) with a bolt via a joint 7, and the two left and right fixing jigs 5 are connected to the lower movable platen of the testing machine. 8 was fixed with bolts through a joint 9.

  Next, in this state, the movable platen 8 is displaced so as to be pushed up in the direction of the fixed arm 6 as indicated by the white arrow in the figure, and the disk 1 of the test body 3 is moved to the position shown in FIG. As shown in the figure, the test body 3 is strained and deformed in a direction orthogonal to the stacking direction, and from this state, the movable platen 8 is moved in a direction opposite to the direction of the fixed arm 6 as indicated by a white arrow in the figure. The operation of the test body 3 when the disk 1 of the test body 3 is repeatedly distorted or deformed, that is, vibrated, with the operation of displacing it down and returning to the state shown in FIG. A hysteresis loop H (see FIG. 3) indicating the relationship between the displacement (mm) of the disk 1 in the direction perpendicular to the stacking direction and the load (N) was obtained.

The measurement was carried out for 3 cycles under the environment of a temperature of 20 ° C. to obtain the third value. The maximum amount of displacement was set so that the amount of deviation of the two steel plates 2 sandwiching the disc 1 in the direction perpendicular to the stacking direction was 100% of the thickness of the disc 1.
Then, connecting the maximum displacement point and the minimum displacement point of the hysteresis loop H shown in FIG. 3 obtained by the measurement, determine the slope Keq (N / mm) of the straight line L ₁ shown by a thick solid line in the figure, the From the inclination Keq (N / mm), the thickness T (mm) of the disc 1, and the cross-sectional area A (mm ² ) of the disc 1, the formula (1):

The equivalent shear modulus Geq (N / mm ² ) was determined by Then, relative values of the equivalent shear elastic modulus Geq (N / mm ² ) of each of the examples and the comparative example were obtained when the equivalent shear elastic modulus Geq (N / mm ² ) in Comparative Example 1 was set to 100.
Also, the absorbed energy amount ΔW represented by the total surface area of the hysteresis loop H shown with diagonal lines in FIG. 3, the straight line L ₁ shown with a mesh line in the figure, and the horizontal axis, and a straight line L ₁ and the hysteresis loop H elastic strain energy W represented by the surface area of the region surrounded by the perpendicular L ₂ grated on the horizontal axis from the intersection of the formula (2):

Thus, an equivalent damping constant Heq was obtained. It can be determined that the greater the equivalent damping constant Heq is, the better the specimen 3 is in damping performance. Accordingly, the relative values of the equivalent attenuation constants Heq of each of the examples and the comparative examples were obtained when the equivalent attenuation constant Heq in the comparative example 1 was set to 100.
(Durability evaluation during large deformation)
Except that the maximum displacement amount was set so that the deviation amount of the two steel plates 2 sandwiching the disc 1 in the direction perpendicular to the stacking direction was 300% of the thickness of the disc 1; Similarly, the state of the disk 1 was observed when the displacement was repeated in an environment at a temperature of 20 ° C.

And, when the number of cycles is within 10 cycles, the disk 1 is largely deformed so that it does not return to its original shape or is damaged. Those that did not give rise to good durability (◯).
<Processability evaluation>
In order to prepare the highly attenuated compositions of Examples and Comparative Examples, each component was put into a kneader and kneaded, and then it was evaluated based on Comparative Example 1 whether it took time to take out the components from the kneader. did.

That is, after kneading, it took a lot of time to take out as much as or more than that of Comparative Example 1, poor workability (x), low adhesiveness, and easy to take out than Comparative Example 1. Evaluated as good (◯).
The results are shown in Table 2.

From the results of Examples 1 to 3 and Comparative Examples 1 and 4 in Table 2, the green strength immediately after kneading of the highly attenuated composition was obtained by using modified calcium carbonate in combination with silica instead of surface-treated calcium carbonate. It has been found that it can be easily taken out from the kneader to further improve the workability, and the damping performance of the high damping member can be improved.
However, from the results of Examples 1 to 3 and Comparative Example 2, in order to obtain the above effect, the blending ratio of the modified calcium carbonate needs to be 1 part by mass or more per 100 parts by mass of natural rubber as a base polymer. It turns out that there is.

Further, from the results of Examples 1 to 3 and Comparative Example 3, in order to improve the durability at the time of large deformation of the high damping member, the blending ratio of the modified calcium carbonate is 100 parts by mass of natural rubber as a base polymer. It was found that it was necessary to be 30 parts by mass or less.
<Examples 4 to 6, Comparative Examples 5 and 6>
The mixing ratio of silica is 80 parts by mass (Comparative Example 5), 100 parts by mass (Example 4), 150 parts by mass (Example 5), 180 parts by mass (Example 6) per 100 parts by mass of natural rubber as a base polymer. ) And 190 parts by mass (Comparative Example 6), a highly attenuated composition was prepared in the same manner as in Example 2.

  With respect to the high attenuation compositions of each of the examples and comparative examples, the above tests were performed to evaluate the characteristics. The results are shown in Table 3 together with the results of Example 2.

From the results of Examples 2, 4 to 6 and Comparative Example 5 in Table 3, in order to give good damping performance to the high damping member, the blending ratio of silica is 100 per 100 parts by mass of natural rubber as the base polymer. It was found that it was necessary to be at least part by mass.
In addition, from the results of Examples 2, 4 to 6, and Comparative Example 6, in order to prevent the durability when the high attenuation member is repeatedly largely deformed, and the high attenuation member is damaged. It has been found that the blending ratio of silica needs to be 180 parts by mass or less per 100 parts by mass of natural rubber as a base polymer.

DESCRIPTION OF SYMBOLS 1 Disc 2 Steel plate 3 Specimen 4 Center fixing jig 5 Left and right fixing jig 6 Fixed arm 7 Joint 8 Movable platen 9 Joint H Hysteresis loop L ₁ straight line L ₂ perpendicular line Keq inclination W energy ΔW absorbed energy amount

Claims (2)

Modified calcium carbonate having a surface polymer treated with a silane coupling agent on the outermost surface of 100 parts by weight or more and 180 parts by weight or less of silica and 1 part by weight or more and 30 parts by weight or less per 100 parts by weight of the base polymer A highly attenuated composition characterized by comprising: A viscoelastic damper for a building, comprising a viscoelastic body formed using the high damping composition according to claim 1 as a forming material.

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