JP2006052328A - Highly damping rubber composition and seismic isolation structure using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly damping rubber composition which maintains rigidity, imparts a high damping property, has high stiffness, and simultaneously has excellent breaking strength and processability. <P>SOLUTION: This highly damping rubber (composition) 2 used in a seismic isolation structure 1 and comprising 100 pts. wt. of a rubber component comprising a dienic rubber, 40 to 95 pts. wt. of carbon black having a cetyltrimethylammonium bromide adsorption specific surface area (CTAB) of 100 to 170 m<SP>2</SP>/g, and 5 to 50 pts. wt. of a resin, is characterized in that ≥10 wt.% of the amount of the compounded resin comprises an aromatic oligomer containing a di- or tri-cyclic heterocyclic aromatic component containing at least one of nitrogen or sulfur in the ring-forming components in an amount of ≥60 wt.%. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a high-damping rubber composition, and relates to a high-damping rubber composition that is excellent in damping performance and fracture strength, and that can be processed with good rigidity while having high rigidity, and a seismic isolation structure using the same. .

  For base isolation of buildings and support of structures such as bridges and elevated roads, seismic isolation structures in which rubber compositions and hard plates such as steel plates are alternately stacked are used. This seismic isolation structure is an elastic structure with high rigidity in the vertical direction and low rigidity in the shear direction. By reducing the natural frequency of the building against the vibration frequency of the earthquake, the vibration input can be reduced. It reduces acceleration and minimizes damage to buildings, people in them, and equipment.

  As a high damping rubber composition for such applications, diene rubber is used as a rubber component, and a large amount of fine carbon black and petroleum resin are blended in order to impart high damping properties (Patent Literature). 1, 2).

In addition, aromatic oligomers that are blended in resins, rubbers, etc. and can be used as tackifiers or vibration-damping agents in the fields of paints, building materials, electrical parts, automotive parts, etc. are described in the following documents (patent documents) 3).
Japanese Patent Laid-Open No. 10-110064 Japanese Patent Laid-Open No. 10-176083 JP 2003-55423 A

  However, the high-damping rubber composition according to the prior art can improve the rigidity of the rubber by adding a large amount of carbon black and impart high damping properties. However, the increase in rubber viscosity causes the unvulcanized rubber to be kneaded or extruded. There are problems in that the scouring process is adversely affected and the processability is lowered, and the breaking strength and breaking elongation due to an increase in rubber hardness are lowered.

  In addition, when the amount of petroleum resin blended with carbon black is increased in order to improve the damping property of the rubber composition and improve the processability, rigidity (elastic modulus) cannot be ensured due to its softening effect. Therefore, it is attempted to maintain rigidity by adding a phenolic resin or the like that has a low softening effect. However, such a resin can maintain rigidity, but the damping performance is low. The reality is that it is unavoidable to deteriorate.

  Therefore, the present invention uses a specific resin component to suppress the softening action by the conventional resin and to provide high damping while maintaining the rigidity of the rubber composition, and to provide high strength and high fracture strength. An object of the present invention is to provide a highly attenuated rubber composition having excellent processability.

  The present inventors have found that by blending a specific aromatic oligomer as a resin component with fine carbon black, the present invention can maintain high attenuation while suppressing the softening effect due to the blending of the above conventional resins. It reached.

That is, high damping rubber composition of the present invention, the rubber component 100 parts by weight of a diene rubber, carbon black 40 to 95 wt cetyl trimethyl ammonium bromide adsorption specific surface area (CTAB) is 100~170m ² / g And 5 to 50 parts by weight of resin, and 10% by weight or more of the resin content is 60 to 2 by weight of 2 to 3 polycyclic heteroaromatic components containing at least one of nitrogen and sulfur as ring components. It is characterized by comprising an aromatic oligomer containing at least%.

  In the present invention, the aromatic oligomer preferably has a weight average molecular weight of 300 to 2,000.

According to the high damping rubber composition of the present invention, the fine carbon black having a CTAB of 100 to 170 m ² / g improves the rigidity (elastic modulus) of the rubber composition and imparts high damping to the rubber composition. The resin component is moderate by making 10 wt% or more of the resin blending amount an aromatic oligomer containing 2 to 3 polycyclic heteroaromatic components containing at least one of nitrogen and sulfur as a ring component and 60 wt% or more. Thus, the fracture strength and workability can be ensured without deteriorating the rigidity and damping property of the rubber composition by adding a resin.

  In other words, by blending the above aromatic oligomers or using in combination with other resins such as petroleum resins and phenolic resins, the softening properties intermediate between petroleum resins and phenolic resins can be maintained while maintaining the damping performance. Thus, excessive softening of the rubber composition can be suppressed by the blending amount of the oligomer to maintain rigidity, damping property and strength, and processability by blending a large amount of carbon black can be improved.

  And, in the seismic isolation structure using the high damping rubber composition, the high damping rubber absorbs and attenuates vibration energy such as earthquakes, and has excellent durability for maintaining the vibration damping effect stably for a long period of time. It becomes.

  The high damping rubber composition of the present invention maintains the rigidity and high damping property of the rubber composition and has excellent fracture strength and workability, and absorbs vibration energy such as various types of seismic isolation, seismic isolation, and vibration removal. It can be suitably used for a seismic isolation structure that excels.

  Hereinafter, embodiments of the present invention will be described.

  The high-damping rubber composition of the present invention contains carbon black having specific colloidal characteristics in a diene rubber component and a specific aromatic oligomer as a resin component.

  The rubber component used in the high damping rubber composition of the present invention is mainly composed of a diene rubber. Diene rubbers include natural rubber (NR), isoprene rubber (IR), various styrene butadiene rubbers (SBR), various butadiene rubbers (BR), cis-1, modified with syndiotactic-1,2 polybutadiene, 4-Butadiene rubber (VCR), nitrile butadiene rubber (NBR), chloroprene rubber (CR) and the like can be mentioned, and these can be used alone or in combination of two or more.

  Of these, NR and IR natural rubber rubber components are preferred from the viewpoint of the balance of mechanical strength characteristics, damping properties, processability, etc., and NR and / or IR is the main component and BR or VCR is blended to attenuate. It may be improved in properties and low temperature characteristics.

The carbon black used in the present invention has a cetyltrimethylammonium bromide adsorption specific surface area (CTAB) of 100 to 170 m ² / g, and its blending amount is 40 to 95 parts by weight with respect to 100 parts by weight of the diene rubber component. is there.

The fine carbon black having a CTAB of 100 to 170 m ² / g can make the rubber composition highly rigid (high elasticity) and excellent in damping properties. If the CTAB of the carbon black is less than 100 m ² / g, the particle size becomes large and good damping performance cannot be obtained, and if it exceeds 170 m ² / g, the dispersibility deteriorates, and the Mooney viscosity of the unvulcanized rubber also increases. The processability such as kneadability and extrudability rises and the rubber hardness increases and the rubber properties deteriorate. When this upper limit is exceeded, it is difficult to achieve both damping performance and processability and rubber properties. CTAB is a measured value based on ASTM D3765.

  Further, if the blending amount of carbon black is less than 40 parts by weight with respect to 100 parts by weight of the diene rubber component, it is difficult to obtain a desired damping performance, and if it exceeds 95 parts by weight, the dispersibility of carbon black is deteriorated and the strength, elongation, etc. This is not preferable because the rubber properties of the resin deteriorate and the processability deteriorates. Of course, in the present invention, carbon black other than the carbon black limited to the CTAB may be used in combination.

  In the high damping rubber composition of the present invention, 5 to 50 parts by weight of the resin is blended with 100 parts by weight of the diene rubber component, and 10 to 10% by weight of the blended amount of the resin is 2 to 3 polycyclic heteroaromatics. An aromatic oligomer containing at least 60% by weight of a group component is blended.

  This aromatic oligomer can moderately suppress the softening effect while having the damping performance as a resin equivalent to that of other petroleum resins, suppress the amount of carbon black in a high-rigidity compound system, Workability can be improved while being rigid.

  In particular, the polycyclic heteroaromatic component of the aromatic oligomer preferably contains at least one of nitrogen and sulfur as a ring component, and exhibits good damping properties by improving compatibility with rubber components and carbon black. can do.

  The polycyclic heteroaromatic component includes 2-ring aromatic components such as naphthalene, methylnaphthalene, and dimethylnaphthalene, tricyclic aromatic components such as acenaphthene, fluorene, and anthracene, and 2 to 2 such as benzothiophene and methylbenzothiophene. What is necessary is just to include nitrogen and sulfur by substituting for the ring-constituting carbon atom of the three-ring heteroaromatic component, and the number of non-carbon atoms and the position of substitution are not particularly limited.

  Components other than the polycyclic heteroaromatic component contained in the aromatic oligomer include aromatic hydrocarbon components, for example, bicyclic aromatic components such as naphthalene, methylnaphthalene, dimethylnaphthalene, acenaphthene, fluorene, anthracene In addition, there are 2 to 3 ring aromatic components such as benzothiophene and methylbenzothiophene, and the substituent is substituted with an alkyl group such as a methyl group or a nitroso group. Or a mixture thereof.

  The aromatic oligomer used in the present invention is a known reaction in which a mixture of a polycyclic heteroaromatic component and other aromatic components is reacted using an inorganic acid such as sulfuric acid or phosphoric acid or an organic acid such as oxalic acid as a catalyst. It is obtained by a method, and obtained by reacting the polycyclic heteroaromatic component and other aromatic components with phenols such as phenol and alkylphenol, or formaldehydes such as formaldehyde with the acid catalyst as a catalyst. As long as the polycyclic heteroaromatic component contains 60% by weight or more in the oligomer, it may be used. When this content is less than 60% by weight, the damping performance is deteriorated.

  Moreover, it is preferable that the weight average molecular weight of an aromatic oligomer exists in the range of 300-2000, and when the molecular weight exceeds 2000, the said moderate softening effect | action will not appear easily and it is unpreferable.

  The weight average molecular weight of this aromatic oligomer is the type and mixing ratio of 2 to 3 ring aromatic compounds, the weight ratio with phenols and formaldehydes, the type of catalyst, reaction conditions (temperature, time, distillation after reaction, etc. ) And the like.

  The softening action of the aromatic oligomer containing such a polycyclic heteroaromatic component shows intermediate characteristics between conventional petroleum resins and phenolic resins, and this aromatic oligomer can be used alone, You may mix | blend and use with other resin.

  When used in combination with other resins, the total resin properties including other petroleum resins and phenolic resins can be adjusted by blending aromatic oligomers with 10% by weight or more of the resin compounding amount, that is, softening of the resin By making the action lower than that of petroleum resin and higher than that of phenolic resin, an appropriate softening action can be obtained taking advantage of both.

  As a result, the fracture strength and workability can be improved while ensuring the high rigidity and damping performance of the carbon black composition, and the amount of carbon black can be suppressed. If the blending amount of the aromatic oligomer is less than 10% by weight, the effect using the aromatic oligomer cannot be sufficiently obtained, and it becomes difficult to balance the characteristics of the rubber composition.

  The blending amount of the total resin including the aromatic oligomer is 5 to 50 parts by weight with respect to 100 parts by weight of the rubber component. If the blending amount of the resin is less than 5 parts by weight, the effect of improving the attenuation by the resin cannot be obtained. However, the processability deteriorates, causing problems in the rubber kneading and processing steps. When the amount exceeds 50 parts by weight, the viscosity of the unvulcanized rubber is greatly reduced, making the rubber kneading step difficult, and the rubber composition does not stick. As a result, the workability such as roll adhesion is deteriorated, and the creep property of the vulcanized rubber is also increased, so that the damping property and durability are lowered.

  Examples of the resin other than the aromatic oligomer used in the present invention include petroleum resins obtained by polymerizing C5 and C9 petroleum fractions such as olefins and diolefins, coumarone-indene resins and coumarone resins / naphthenes. Coumarone resin such as mixed oil / phenolic resin / rosin, phenol-acetylene resin, phenol-formaldehyde resin, terpene-phenolic resin, polyterpene resin, phenol-terpene resin such as xylene-formaldehyde resin, aromatic And petroleum hydrocarbon resins such as aliphatic hydrocarbon resins, aliphatic hydrocarbon resins, and aliphatic-aromatic petroleum resins. These can be used alone or in combination of two or more.

  In addition to the rubber component, carbon black, thermosetting resin, and resin, the high-damping rubber composition of the present invention includes a vulcanizing agent such as sulfur that is usually used in the rubber industry, vulcanization, as necessary. Additives such as accelerators, silica, silane coupling agents, anti-aging agents, zinc white, stearic acid, oil and other softeners, waxes, various fillers, plasticizers, various resins, etc. within the range of normal compounding amounts It can mix | blend suitably.

  The high-damping rubber composition of the present invention can be obtained by mixing the above components using a rubber mixer usually used in the rubber industry such as a Banbury mixer or a kneader.

  The seismic isolation structure of the present invention is a structure comprising a rubber member made of the high damping rubber composition and a hard plate such as a steel plate.

  As this seismic isolation structure, there is provided a seismic isolation structure 1 having a high damping rubber layer 2 and a hard plate 3 alternately laminated as shown in FIG. 1 and having flanges 4 and 4 'on the upper and lower surfaces. The internal structure, shape, size, and the like are not limited, and the shape can be selected depending on the use such as a rectangular column shape, a polygonal column shape, an elliptical column shape in addition to a columnar shape, and the hard plate and the flange may be a cold rolled steel plate or Various materials such as various metal plates, ceramic materials, and reinforced plastic materials such as FRP are used.

  The manufacturing method of the seismic isolation structure is a method of laminating a sheet-like rubber member obtained by molding and vulcanizing a high-damping rubber and a hard plate or a flange and bonding them with an adhesive, or an unmolded sheet-like structure. It can be manufactured by laminating vulcanized high damping rubber with a hard plate or flange and vulcanizing and bonding.

  This seismic isolation structure has a stable effect on the absorption of vibration energy such as base isolation of buildings and detached buildings, isolation of bridges and road supports, vibration isolation, vibration isolation, etc. be able to.

  Hereinafter, the present invention will be described in more detail with reference to examples.

  For each example and comparative example shown in Table 1, with respect to 100 parts by weight of natural rubber (corresponding to NR, RSS # 3), carbon black with limited CTAB, aromatic oligomer containing a polycyclic heteroaromatic component, A phenolic resin, a petroleum resin (A) (B), and a plasticizer (process oil) are blended in the blending amounts (parts by weight) shown in Table 1, and a normal sealed type together with the following common blending components (parts by weight). Each rubber composition was prepared by kneading using a Banbury mixer.

[Carbon black, resin and plasticizer]
Carbon black: CTAB = 135 m ² / g
Aromatic oligomer: oligomer having a naphthalene content of 80% and a weight average molecular weight of 1500. Phenol resin: PR12686R manufactured by Sumitomo Bakelite Co., Ltd.
Petroleum resin (A): High Resin # 130, manufactured by Toho Chemical Industry Co., Ltd.
・ Petroleum resin (B): High Resin # 90 manufactured by Toho Chemical Industry Co., Ltd.

[Common ingredients and amounts]
・ Zinc flower: 3 parts by weight (No. 3 zinc flower)
・ Stearic acid: 2 parts by weight (industrial stearic acid)
Anti-aging agent: 3 parts by weight (manufactured by Flexis Co., Ltd., Santoflex 13)
・ Plasticizer: 2 parts by weight (aromatic process oil)
・ Sulfur: 2 parts by weight (5% oil-treated powdered sulfur)
・ Vulcanization accelerator: 1.2 parts by weight (Ouchi Shinsei Chemical Co., Ltd., Noxeller CZ)

  Each rubber composition obtained was evaluated for processability, basic physical properties (tensile strength, elongation at break), and seismic isolation characteristics according to the following methods, and the results are shown in Table 1. In Example 1, 50 parts by weight of carbon black was blended and the resin was changed to compare the effects. In Examples 2 and 3, 90 parts by weight of carbon black was blended and a petroleum resin was used in combination.

[Machinability]
The Mooney viscosity (ML (1 + 4), temperature 100 ° C.) of each highly damped rubber composition was measured according to JIS K6300 and used as an index of processability. The smaller the value, the better the workability.

[Tensile strength, elongation at break]
The tensile strength (TB) and elongation at break (EB) of each high-damping rubber composition were measured according to JIS K6251 (using No. 3 dumbbell). The higher the number, the better.

[Seismic isolation characteristics]
A "2-block lap shear type" specimen (rubber part: width 25 mm, length 25 mm, thickness 5 mm) shown in FIG. 2 is vulcanized using each rubber composition, and then using a hydraulic vibration tester. Shear excitation was applied at a frequency of 0.5 Hz under the following three series of strain conditions to obtain a stress-strain curve as shown in FIG. 3, and the shear elastic modulus (Geq) and vibration absorption characteristics (Heq) were determined. The measurement temperature was 20 ° C.

Strain excitation condition 1st series: Excitation is performed 10 times with a strain of 100%.
Second series: Excitation is performed 10 times with a strain of 200%.
3rd series: Excitation twice with 100% strain.

  For the tenth vibration in the first series and the second vibration in the third series, Geq and Heq are calculated from the following equations (1) and (2) from the stress-strain curve shown in FIG. Table 1 shows Geq and Heq of the rubber composition. Geq is an index of rigidity and is set to an arbitrary value, and Heq is an index of attenuation, and the larger the better.

Geq (Kgf / cm ² ) = F / 2 (1)
Heq (%) = (ΔW / (W1 + W2)) × 1 / 2π × 100 (2)
Here, ΔW is the area in the loop of the stress-strain curve in FIG. 3, and W1 and W2 are the areas of the triangular regions in FIG.

  From the results of Table 1, the comparative example 2 containing the petroleum resin (A), compared with the comparative example 1 containing no resin, decreases the Mooney viscosity to improve the workability and improve the damping performance (Heq). The composition is excessively softened and the rigidity (Geq) is greatly reduced. Comparative Example 3 containing a petroleum resin (B) whose softening action is smaller than that of petroleum resin (A) improves or maintains rigidity and damping to some extent, but does not satisfy improvement in workability, and has a low softening action. Comparative Example 4 blended with a slightly improved workability than Comparative Example 1, but the physical properties and damping properties showed a tendency to decrease and lacked in the balance of performance, and those using conventional resins all had a balance in performance. I'm not satisfied. On the other hand, Example 1 which mix | blended the aromatic oligomer maintains that rigidity and damping performance are maintained, and it turns out that fracture strength and workability are balanced.

  In Examples 2 and 3, in which the carbon black content was 90 parts by weight and the aromatic oligomer and petroleum resin were used in combination, the breaking strength and processability were maintained, and the damping property was improved while obtaining an arbitrary rigidity value. This makes it possible to reduce the amount of carbon black.

  As described above, the highly damped rubber composition according to the present invention has excellent seismic isolation performance while suppressing the increase in viscosity of unvulcanized rubber, maintaining processability and maintaining good process stability. It can be suitably used for various seismic isolation structures such as buildings and building structures, bridges and road supports.

It is a seismic isolation structure to which the high damping rubber composition of the present invention is applied. It is a perspective view of a "2 block lap shear type" test body. It is explanatory drawing of a stress-strain curve.

Explanation of symbols

1 …… Seismic isolation structure 2 …… High damping rubber 3 …… Hard plate 4, 4 ′ …… Flange

Claims (3)

40 to 95 parts by weight of carbon black having a cetyltrimethylammonium bromide adsorption specific surface area (CTAB) of 100 to 170 m ² / g and 5 to 50 parts by weight of resin with respect to 100 parts by weight of the rubber component made of diene rubber. ,
10% by weight or more of the amount of the resin is composed of an aromatic oligomer containing 60% by weight or more of a 2 or 3 ring polyaromatic component containing at least one of nitrogen and sulfur as a ring component. High damping rubber composition. The high-damping rubber composition according to claim 1, wherein the aromatic oligomer has a weight average molecular weight of 300 to 2,000. A high-attenuation rubber composition according to claim 1 or 2 is used.

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