JP5377025B2 - Rubber bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high damping rubber composition which has high damping performance and vulcanization rate and is suitable for use in large bearings e.g. for bridges and buildings and a rubber bearing using the rubber composition. <P>SOLUTION: The isolation bearing is composed of stiffening plates 1 and rubber layers 2 laminated alternatively with one on the other to form an integrated single body. The rubber layers 2 contain components (A)-(C) and are formed of a high damping rubber composition in which the content of the component (B) is set in the range of 5-100 pts.wt. relative to 100 pts.wt. of the component (A). (A): Diene rubber. (B): Pitch-based carbon fiber filler having an average fiber diameter of 4-15 &mu;m and an average fiber length of 10 &mu;m-10 cm. (C): Sulfur-based vulcanizing agent. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

The present invention relates to a rubber bearing body using a high-damping rubber composition having anti-vibration characteristics and seismic isolation characteristics.

  In recent years, the progress of bridge technology has been remarkable, and the scale of the bridge has been increasing year by year, and a long bridge has been designed accordingly. For the construction of the long bridge, usually a large number of rubber supports are installed on the piers arranged at predetermined intervals, and a long span bridge girder is installed on the pier via these supports. Done. By interposing the rubber bearing body in this way, functions such as anti-vibration support and seismic isolation support can be effectively obtained in the long bridge. By the way, since a very large load is applied to the rubber bearing body, usually a rigid hard plate such as a metal plate is alternately laminated and integrated with a rubber layer so that the load support is excellent, It is formed.

  As a material for the rubber layer, conventionally, a rubber composition having excellent damping properties and mainly composed of natural rubber or diene synthetic rubber has been used. However, since natural rubber and diene synthetic rubber alone are somewhat inferior in target damping properties, fillers such as carbon black for assisting damping characteristics are usually blended in the rubber composition ( Patent Literatures 1 to 3).

JP 2001-164044 A WO98 / 32794 gazette JP-A-11-132274

  By the way, since the support body for bridges and buildings is large-sized, in order to sufficiently spread the heat inside the product (center part) during the production and vulcanize the rubber composition, Heating for a long time (around 20 hours) is required. This is due to the property of rubber that is inferior in heat conductivity (it is difficult to conduct heat).

  When carbon black is blended in the rubber composition as described above, since carbon black has thermal conductivity, a certain degree of vulcanization speed improvement effect can be expected even in the use of the large product. However, it is necessary to add a large amount of carbon black in order to exhibit the desired thermal conductivity. Addition of such a large amount of carbon black is accompanied by a decrease in the elongation of the rubber layer and an increase in hardness, thereby causing a decrease in physical properties (degradation of function) of the rubber support, and the rubber composition (unvulcanized rubber). There is also concern about deterioration of workability (handling) due to an increase in viscosity.

  It is also possible to increase the vulcanization speed by adjusting the type and amount of the vulcanizing agent and vulcanization accelerator. However, such a method is likely to cause rubber scorching and storage stability. There is a risk of causing adhesion failure, appearance failure, and the like.

The present invention has been made in view of such circumstances, and uses a high-damping rubber composition that is highly damped, has a high vulcanization speed, and is suitable for use in large bearings such as for bridges and buildings. Its purpose is to provide a rubber bearing.

In order to achieve the above object, the present invention provides a highly damped rubber composition comprising the following (A) as a main component and the following (B) and (C) components, wherein (A) component 100: relative parts by weight, the rubber bearing body formed have use high damping rubber composition is set in a range content ratio of 5 to 100 parts by weight of component (B), the gist of it.
(A) Diene rubber.
(B) A pitch-based carbon fiber filler having an average fiber diameter of 4 to 15 μm and an average fiber length of 10 μm to 10 cm.
(C) Sulfur-based vulcanizing agent.

  That is, the inventors of the present invention, as a highly attenuated rubber composition suitable for large bearing applications such as for bridges and buildings with high attenuation and high vulcanization speed, are firstly used in diene rubber compositions. The use of a material containing a thermally conductive filler was investigated. However, conventionally known heat conductive fillers for rubber such as carbon black and metal oxides (alumina, zinc oxide, etc.) need to be added in a large amount to improve the vulcanization rate as described above. Therefore, there are concerns about problems such as deterioration of physical properties and deterioration of workability. Therefore, various types of non-rubber fillers were examined and experiments were repeated. As a result of the experiment, when a pitch-based carbon fiber filler having an average fiber diameter of 4 to 15 μm and an average fiber length of 10 μm to 10 cm is blended, the carbon fibers are finely dispersed in the rubber even if the blending amount is small. As a result, the present inventors have found that a medium for transferring heat can be realized and an improvement in the vulcanization speed can be realized without causing the above-mentioned problems.

As described above, rubber scaffold of the present invention, the diene rubber composition, identified an average fiber diameter of a range of 4-15 .mu.m, pitch-based carbon fiber filler having an average fiber length 10μm~10cm [component (B)] weight What is contained (high damping rubber composition) is used . Therefore, it has high damping and heat conduction during rubber composition vulcanization is good, so the vulcanization speed is fast, and it has an excellent effect for large support applications such as for bridges and buildings. It can be demonstrated.

In particular, when the carbon fiber filler [component (B)] has a crystallite size derived from the growth direction of the hexagonal network surface of 5 nm or more, the vulcanization of the highly attenuated rubber composition used in the rubber support of the present invention. The speed can be further increased, and an excellent effect can be exhibited in large-sized bearings such as those for bridges and buildings as described above.

The true density of the carbon fiber filler [component (B)] is in the range of 1.5 to 2.3 g / cc, and the thermal conductivity in the fiber axis direction is 300 W / m · K or more. The vulcanization rate of the high damping rubber composition used in rubber bearings can be increased, and it has excellent effects for large bearings such as those for bridges and buildings as described above Can do.

It is sectional drawing which shows an example of the seismic isolation bearing body of this invention. It is sectional drawing which shows the other example of the seismic isolation bearing body of this invention. It is sectional drawing which shows the other example of the seismic isolation bearing body of this invention.

  Next, embodiments of the present invention will be described in detail.

The high damping rubber composition used for the rubber support of the present invention is a pitch-based carbon fiber filler (B component) having a diene rubber (component A) as a main component, an average fiber diameter of 4 to 15 μm, and an average fiber length of 10 μm to 10 cm. ) And a sulfur-based vulcanizing agent (C component), and the content ratio of the carbon fiber filler (B component) is set in a specific range. In the present invention, the above “main component” means a material that greatly affects the properties of the composition, and usually means 55% by weight or more of the whole.

  Examples of the diene rubber [component (A)] include natural rubber (NR), butadiene rubber (BR), styrene-butadiene rubber (SBR), isoprene rubber (IR), acrylonitrile-butadiene rubber (NBR), and ethylene. -Propylene-diene terpolymer (EPDM) and the like. These may be used alone or in combination of two or more. Of these, NR and BR are preferable from the viewpoints of strength, oil resistance, heat resistance and the like.

  And as a heat conductive filler used with the said (A) component, as mentioned above, the pitch-type carbon fiber filler [(B) component] with an average fiber diameter of 4-15 micrometers and an average fiber length of 10 micrometers-10 cm is mentioned. Used. Preferably, a carbon fiber filler having an average fiber length of 50 μm to 25 mm and an average fiber diameter of 8 to 10 μm. That is, if the average fiber diameter of the carbon fiber filler is less than the above range, the thermal conductivity tends to deteriorate. Conversely, if the average fiber diameter exceeds the above range, the change in material properties is greatly affected. (The rubber becomes harder and the elongation becomes worse). Further, if the average fiber length of the carbon fiber filler is less than the above range, high thermal conductivity (desired vulcanization speed improvement effect) cannot be exhibited. Conversely, the average fiber length is within the above range. This is because workability (handling) deteriorates during weighing before kneading the rubber compound. In addition, the said average fiber diameter and average fiber length can be measured by SEM (electron microscope) observation etc., for example.

  In particular, the specific pitch-based carbon fiber filler (component (B)) preferably has a crystallite size derived from the growth direction of the hexagonal network surface of 5 nm or more. More preferably, it is 20 nm or more, and more preferably 30 nm or more. That is, by setting in such a range, the vulcanization speed of the high damping rubber composition can be increased, and even when used for large bearings such as for bridges and buildings, the This is because heat can be quickly distributed to the inside (center) of the product, and the vulcanization time can be shortened. The crystallite size derived from the growth direction of the hexagonal network surface can be obtained, for example, by diffraction lines from the (110) plane of the carbon crystal obtained by the X-ray diffraction method. The reason why the crystallite size is important is that heat conduction is mainly performed by phonons, and it is the crystals that generate phonons.

The specific pitch-based carbon fiber filler (component (B)) has a true density of 1.5 to 2.3 g / cc and a thermal conductivity in the fiber axis direction of 300 W / m · K or more. It is preferable. That is, by setting in such a range, the vulcanization speed of the high-damping rubber composition used in the rubber bearing body of the present invention can be increased, and large bearings such as for bridges and buildings can be used. This is because even when used for body use, heat can be quickly distributed to the inside (center part) of the product, and the vulcanization time can be shortened.

  Examples of the raw material for the specific pitch-based carbon fiber filler [component (B)] include condensed polycyclic hydrocarbon compounds such as naphthalene and phenanthrene, condensed heterocyclic compounds such as petroleum-based pitch and coal-based pitch, and the like. These may be used alone or in combination of two or more. Of these, condensed polycyclic hydrocarbon compounds such as naphthalene and phenanthrene are preferred from the viewpoint of improving thermal conductivity and increasing the vulcanization rate, and optically anisotropic pitch, that is, mesophase pitch is particularly preferred.

  And the said specific pitch type carbon fiber filler [(B) component] discharges the said raw material pitch fuse | melted at about 250-350 degreeC, for example according to the melt blow method etc. from a nozzle mouthpiece, and cools this. After melt spinning is obtained, the melt spinning can be produced by infusibilizing, firing and pulverizing and finally graphitizing.

  The infusibilization is achieved at 200 to 350 ° C. using air or a gas obtained by adding ozone, nitrogen dioxide, nitrogen, oxygen, iodine, or bromine to air. Considering safety and convenience, it is preferable to carry out in the air. The infusibilized pitch fiber is fired at 600-1500 ° C. in vacuum or in an inert gas such as nitrogen, argon, krypton, and then graphitized at 2000-3500 ° C. In many cases, the graphitization is performed in low-cost nitrogen, and graphitization is generally performed by changing the type of the inert gas according to the type of furnace used. After infusibilization or firing, the obtained fiber is pulverized as necessary. Specifically, the pulverization is performed by using a cutter, a ball mill, a jet mill, a crusher, or the like. The pulverized pitch-based carbon fiber filler is fired as necessary and then graphitized. The graphitization temperature is preferably 2000 to 3500 ° C. in order to increase the thermal conductivity of the carbon fiber. More preferably, it is 2300-3100 degreeC. When graphitizing, it is preferable to place it in a graphite crucible because it can block physical and chemical effects from the outside. The graphite crucible is not limited in size and shape as long as the above-mentioned carbon fiber can be put in a desired amount, but the oxidizing gas in the furnace during graphitization or cooling, Or in order to prevent the said carbon fiber from being damaged by reaction with water vapor | steam, a highly airtight thing with a lid | cover can be utilized suitably.

  The blending ratio of the specific pitch-based carbon fiber filler [(B) component] is in the range of 5 to 100 parts with respect to 100 parts by weight (hereinafter referred to as “part”) of the diene rubber [(A) component]. It is blended with. Preferably it is the range of 10-50 parts. That is, if the blending ratio of the carbon fiber filler is less than the above range, desired thermal conductivity (improvement effect of vulcanization rate) cannot be exhibited, and conversely, the blending ratio of the carbon fiber filler. This is because even if the value is higher than the above range, it only leads to an increase in cost, and no further effect can be expected.

  Examples of the sulfur-based vulcanizing agent [(C) component] used together with the components (A) and (B) include sulfur such as sulfur and sulfur chloride (powder sulfur, precipitated sulfur, insoluble sulfur), and 2-mercapto. Examples include imidazoline and dipentamethylene thiuram pentasulfide. These may be used alone or in combination of two or more.

  The amount of the sulfur vulcanizing agent [component (C)] is preferably in the range of 0.3 to 7 parts, particularly preferably 1 to 5 with respect to 100 parts of the diene rubber [component (A)]. Part range. That is, if the amount of the vulcanizing agent is too small, the vulcanization reactivity tends to be deteriorated. Conversely, if the amount of the vulcanizing agent is too large, the rubber properties (breaking strength, breaking elongation) are lowered. This is because the tendency to do is seen.

  In addition to the above components (A) to (C), the special high attenuation rubber composition includes carbon black, process oil, anti-aging agent, processing aid, vulcanization accelerator, white filler, reaction A functional monomer, a foaming agent and the like may be appropriately blended as necessary.

  And the special high damping rubber composition uses the above components (A) to (C) and other components as required, and these are used as kneaders, Banbury mixers, open rolls, twin screw type stirrers, etc. It can be prepared by kneading using a kneader.

The special high damping rubber composition, for bridges scaffold, Ru is preferably used as a material of a large scaffold such buildings for scaffold.

  For example, as shown in FIG. 1, a seismic isolation support for a bridge or a building is formed by alternately laminating hard plates 1 and rubber layers 2. The rubber layer 2 is formed of the special high damping rubber composition according to the present invention, which is the greatest feature. In the figure, 3 and 4 are metal attachment plates, which are bonded and fixed to the upper and lower portions of the laminate of the hard plate 1 and the rubber layer 2. And in the said seismic isolation bearing body, the lower attachment plate 4 is fixed to lower structures, such as a bridge pier, and the upper attachment plate 3 is fixed to upper structures, such as a bridge girder. It has become.

  As the hard plate 1, for example, a metal plate such as a rolled steel plate or an iron plate, a hard plastic plate material, or the like is used.

  Here, the seismic isolation bearing shown in FIG. 1 is produced as follows, for example. That is, first, the above components (A) to (C) and other components are blended as necessary, and these are mixed using a kneader such as a kneader, a Banbury mixer, an open roll, a mixing roll, or a twin screw type stirrer. By kneading, a rubber composition which is a material for the rubber layer 2 is prepared. Next, a plurality of hard plates 1 having a predetermined size are prepared, and an upper mounting plate 3 and a lower mounting plate 4 are also prepared, and these are set in a molding die so as to have a predetermined arrangement. Note that an adhesive may be applied in advance to the hard plate 1 or the like set in the molding die. Subsequently, the rubber composition prepared above is injected into the gap in the mold by injection or the like, or the rubber composition prepared in advance by a roll or the like is weight-molded and spread on the mold, and the mold is added. Sulfur is performed. And the said rubber composition is heat-vulcanized at 130-180 degreeC for 5-90 minutes. Large rubber products such as seismic isolation bearings require a long time (around 20 hours) to transmit heat to the inside of the product and vulcanize, but the special high damping rubber composition according to the present invention is vulcanized. Since the time can be shortened, even if the vulcanization time is short as described above, sufficient vulcanization can be performed, and an effect of improving production efficiency can be expected. And after the said vulcanization | cure, the target seismic isolation bearing body can be obtained by demolding this.

  Moreover, the seismic isolation bearing body shown in FIG. 1 can also be produced as follows. That is, a rubber composition prepared in the same manner as described above is used to form a rubber sheet (rubber layer 2) having a predetermined thickness by extrusion molding or the like, and this is then used to form a predetermined hard plate 1 using an appropriate adhesive. A rubber block is produced by alternately laminating and adhering to each other, and if necessary, the upper mounting plate 3 and the lower mounting plate 4 are bonded and integrated on the upper and lower surfaces. Thereby, the target seismic isolation bearing can be obtained (refer FIG. 1).

  And the said seismic isolation bearing body by which the hard board 1 and the rubber layer 2 were laminated | stacked alternately and integrated is the rubber layer 2 formed by vulcanizing | curing the said special high damping rubber composition which concerns on this invention. Because it has high performance (thermal conductivity) to dissipate thermal energy generated by absorbing vibrations to the outside air, it is unlikely to cause rubber degradation (thermal degradation) due to durable use, especially for bridges and buildings. Excellent base isolation performance as a support body.

  Note that the seismic isolation bearing shown in FIG. 1 has a rubber layer 2 whose horizontal size is larger than that of the hard plate 1, so that the hard plate 1 is completely in the rubber in its cross section. It is buried. However, the present invention is not limited to such a cross-sectional structure. For example, as shown in FIG. 2, the size of the hard plate 1 in the horizontal direction is the same as the size of the rubber layer 2, and the hard plate The outer peripheral side surface of 1 may be flush with the side surface of the laminate. Moreover, as shown in FIG. 3, the horizontal size of the hard plate 1 may be set to be larger than the size of the rubber layer 2, and may be laminated and integrated as shown. The seismic isolation support shown in FIG. 1 has the advantage of reducing stress concentration at the end due to its structure, and the one shown in FIG. 3 has the advantage of being easy to manufacture.

  The dimension of the seismic isolation bearing body thus obtained is, for example, about 20 to 200 cm in outer diameter, and the total thickness of the base isolation bearing body is about 10 to 80 cm. Further, the thickness of each layer constituting the seismic isolation bearing may be within a range in which the intended function of each layer can be sufficiently achieved. For example, the thickness of the hard plate 1 is 0.1 layer per layer. The thickness of the rubber layer 2 is about 0.5 to 7 cm, and the thickness of the rubber outer skin 5 is about 0.5 to 10 cm. Further, the number of laminated hard plates 1 and rubber layers 2 in the seismic isolation bearing can be appropriately set according to the use of the seismic isolation laminate.

  In addition, the external shape of the said seismic isolation bearing body can be suitably set according to the use, such as columnar shape, elliptical column shape, prismatic shape.

  Next, examples will be described together with comparative examples. However, the present invention is not limited to these examples.

  First, prior to the examples and comparative examples, the following materials were prepared.

[NR]
Natural rubber

[Zinc oxide]
2 types of zinc oxide, made by Mitsui Mining & Mining

〔stearic acid〕
Lunac S30, manufactured by Kao

[Anti-aging agent]
Ozonon 6C, manufactured by Seiko Chemical Co., Ltd.

〔wax〕
Sunnock, Ouchi Shinsei Chemical Co., Ltd.

〔Carbon black〕
Show Black N220, Showa Cabot

[Carbon fiber filler (i)]
Lahima X-A101 (average fiber diameter: 8 μm, average fiber length: 10 μm, true density: 1.0 g / cc, thermal conductivity: about 600 W / m · K), manufactured by Teijin Ltd.

(Carbon fiber filler (ii))
Lahima R-A201 (average fiber diameter: 8 μm, average fiber length: 50 μm, true density: 1.0 g / cc, thermal conductivity: about 600 W / m · K), manufactured by Teijin Ltd.

[Carbon fiber filler (iii)]
GRANOC XN-100-25Z (average fiber diameter: 10 μm, average fiber length: 25 mm, true density: 2.2 g / cc, thermal conductivity: about 900 W / m · K), manufactured by Nippon Graphite Fiber

[Process oil]
Sunsen 410, made by Nippon San Oil Co., Ltd.

[Vulcanization accelerator]
Sunseller CZ-G, manufactured by Sanshin Chemical Co., Ltd.

〔sulfur〕
Sulfur, manufactured by Karuizawa Refinery

[Example 1]
100 parts of NR, 5 parts of zinc oxide, 2 parts of stearic acid, 1 part of anti-aging agent, 2 parts of wax, 30 parts of carbon black, 30 parts of carbon fiber filler (i), and 5 parts of process oil These were blended and kneaded at 140 ° C. for 5 minutes using a Banbury mixer. Next, 2.8 parts of sulfur and 1 part of a vulcanization accelerator were blended therein and kneaded at 60 ° C. for 5 minutes using an open roll to prepare a rubber composition.

[Examples 2-3, Comparative Example 1]
As shown in Table 1 below, a rubber composition was prepared according to Example 1 except that the amount of each component was changed.

  Using the rubber compositions of Examples and Comparative Examples thus obtained, each characteristic was evaluated according to the following criteria. The results are also shown in Table 1 below.

[Vulcanization time]
Using the rubber composition described above, press vulcanization was performed at 150 ° C. to prepare a 9 cm × 9 cm × 4 cm thick rubber test piece. Then, when producing the rubber test piece, compression set (25% compression according to JIS K6262) of a rubber block (3 cm × 3 cm × thickness 1.25 cm) cut out aiming at the central portion, and in an atmosphere at 70 ° C. The vulcanization time (minutes) required for the value of compression set after standing for 24 hours to be 25% or less was measured.

〔Thermal conductivity〕
Using the rubber composition described above, press vulcanization was performed at 150 ° C. to prepare a 9 cm × 9 cm × 4 cm thick rubber test piece. Then, using a rapid thermal conductivity meter device (Kemtherm QTM-D3, manufactured by Kyoto Electronics Industry Co., Ltd.), the probe was pressed against the front and back surfaces of the rubber test piece produced above, and the thermal conductivity (W / m · K). Was measured.

  From the above results, it was possible to shorten the vulcanization time of the example products. In addition, the thermal conductivity of the rubber test piece is high, and therefore, it is presumed that the performance of radiating the thermal energy generated by vibration absorption to the outside air is high, and rubber deterioration (heat deterioration) due to durable use is less likely to occur. From such a result, for example, when using the rubber composition of the example to produce a base-isolated support for the bridge use or the building use having the shape shown in FIGS. 1 to 3, excellent seismic isolation according to the example.・ It is presumed that anti-vibration performance can be demonstrated.

  On the other hand, the product of Comparative Example 1 is dealt with by blending a large amount of carbon black instead of the carbon fiber filler, but the thermal conductivity is lower than that of the product of the Example, so that it was caused by vibration absorption. It is presumed that heat energy is easily stored and rubber deterioration (heat deterioration) or the like occurs due to durable use. In addition, it can be seen that the time required for vulcanization is longer than in the examples and the production efficiency is poor.

  In addition, although the natural rubber (NR) is used as described above for the polymer of the rubber composition of the examples, the above also applies when other diene rubbers (BR, NR / BR blend, etc.) are used. Similar to the examples, excellent results were obtained.

Moreover, even if it is other than the carbon fiber filler used in the examples, if the pitch-based carbon fiber filler has an average fiber diameter of 4 to 15 μm and an average fiber length of 10 μm to 10 cm, it is highly attenuated in the rubber support of the present invention. It has been confirmed by experiments that excellent results can be obtained by using it as a material for the rubber composition, as in Examples.

The high damping rubber composition used for the rubber bearing of the present invention is preferably used as a material for large seismic isolation bearings such as bridge bearings and building bearings. It can also be used for vibration damping dampers for general household electrical appliances such as materials and washing machines.

1 Hard plate 2 Rubber layer

Claims (4)

A highly damped rubber composition comprising the following (A) as a main component and containing the following (B) and (C) components, and the content ratio of the (B) component with respect to 100 parts by weight of the (A) component: rubber scaffold but characterized by comprising using a high damping rubber composition that is set to a range of 5 to 100 parts by weight.
(A) Diene rubber.
(B) A pitch-based carbon fiber filler having an average fiber diameter of 4 to 15 μm and an average fiber length of 10 μm to 10 cm.
(C) Sulfur-based vulcanizing agent. (B) described above of the pitch-based carbon fiber filler of the component, a crystallite size derived from the growth direction of the hexagonal plane is that 5nm or more claims 1 rubber scaffold according. The true density of the pitch-based carbon fiber filler as the component (B) is in the range of 1.5 to 2.3 g / cc, and the thermal conductivity in the fiber axis direction is 300 W / m · K or more. rubber bearing body of the second aspect. The diene rubber as the component (A) is at least one selected from the group consisting of natural rubber, butadiene rubber, styrene-butadiene rubber, isoprene rubber, acrylonitrile-butadiene, and ethylene-propylene-diene terpolymer. rubber bearing as claimed in any one of a claims 1-3.

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