JP5038608B2 - High damping rubber composition - Google Patents

Description

  The present invention relates to a high damping rubber composition used as a high damping material.

  In recent years, various seismic isolation structures have been developed due to an increase in demand for earthquake-resistant buildings. For example, a seismic isolation structure having a laminated structure of a plurality of rubber layers and a plurality of hard plate layers plays a role of attenuating added energy when vibration due to an earthquake or the like is applied to a building. The rubber layer used in the seismic isolation structure or the like is generally called a high damping rubber and uses a rubber component that efficiently absorbs energy.

  Rubber materials exhibit elastic hysteresis (elastic hysteresis phenomenon) due to stress strain, and the greater the hysteresis, the more work is lost. For this reason, at present, a rubber composition having a large hysteresis loss is produced by adding a filler to a rubber material, and this is used as a high damping rubber.

  As a highly attenuating rubber, a rubber composition is known in which a large amount of carbon black is added to a rubber material to increase hysteresis loss (see, for example, Patent Document 1).

  However, in the rubber composition added with carbon black as described above, the hysteresis loss increases, but the elastic modulus of the obtained rubber composition also increases depending on the type, quality, and amount of carbon black added. End up. Similarly, even when a resin-based additive (rosin or petroleum resin) is added, tackiness is likely to increase, and workability during use may be reduced.

  As another means, a technique of adding a resin having a softening point of 150 ° C. or higher is disclosed (for example, see Patent Document 2). In this method, the kneading is not stable when the temperature rise during kneading is small, such as when blending a low elastic rubber, and if the softening point is low, a sufficient hysteresis loss increasing effect cannot be obtained, and There is a problem that there are limitations.

Further, a technology for adding a copolymer of a C9 aromatic hydrocarbon and a C5 aliphatic unsaturated hydrocarbon, which is a petroleum resin (see, for example, Patent Document 3) or a technology for adding an alicyclic hydrocarbon resin ( For example, refer to Patent Document 4.) In any case, in order to obtain a sufficient increase effect of hysteresis loss, the blending amount must be increased, and the rubber tackiness after kneading is reduced. There is a problem that the workability increases.
Thus, it is difficult to achieve improvement in hysteresis loss while maintaining good workability, and a rubber composition excellent in balance between these is desired.
JP 2001-206989 A Japanese Patent Laid-Open No. 9-25364 Japanese Patent No. 2762407 JP-A-2004-27080

  The object of the present invention is to solve the above-described conventional problems. That is, an object of the present invention is to provide a rubber composition having a large hysteresis loss, excellent fracture characteristics and compression set, and capable of exhibiting good workability during use.

As a result of intensive studies to achieve the above object, the present inventor has found that the problem can be solved by adding a small amount by using a specific saturated hydrocarbon resin, and has completed the present invention.
That is, the configuration of the present invention is as follows.
<1> A high-damping rubber composition comprising at least one selected from natural rubber, styrene-butadiene rubber, butadiene rubber, isoprene rubber, and chloroprene rubber, and a hydroxyl group-introduced alicyclic saturated hydrocarbon resin.
< 2 > The highly attenuated rubber composition according to <1 >, wherein the hydroxyl group-introduced alicyclic saturated hydrocarbon resin is a resin obtained by introducing a hydroxyl group into the ring structure of the alicyclic saturated hydrocarbon resin. object.
< 3 > The highly attenuated rubber composition according to < 2 >, wherein the hydroxyl group is a phenolic hydroxyl group or an alcoholic hydroxyl group.
< 4 > The high attenuation according to any one of <1> to < 3 >, wherein the hydroxyl value of the hydroxyl group-introduced alicyclic saturated hydrocarbon resin is 2 to 400 (mgKOH / g). Rubber composition.
< 5 > The high attenuation rubber composition according to any one of <1> to < 4 >, wherein the hydroxyl group-introduced alicyclic saturated hydrocarbon resin has a weight average molecular weight of 300 to 4000.
< 6 > The hydroxyl group-introduced alicyclic saturated hydrocarbon resin is selected from a resin obtained by hydrogenating a petroleum resin having a hydroxyl group and a resin obtained by polymerizing a monomer having a hydroxyl group <1> thru | or < 5 > High attenuation rubber composition of any one of < 5 >.
< 7 > The hydroxy group-introduced alicyclic saturated hydrocarbon resin is contained in an amount of 2 to 60 parts by mass per 100 parts by mass of the rubber component, according to any one of <1> to < 6 >. High damping rubber composition.

  According to the present invention, it is possible to provide a rubber composition having a large hysteresis loss, excellent fracture characteristics and compression set, and capable of exhibiting good workability during use.

The highly damped rubber composition of the present invention contains at least a rubber component and a polar alicyclic hydrocarbon resin (hereinafter referred to as a specific hydrocarbon resin as appropriate).
Hereinafter, the components of the rubber composition of the present invention will be sequentially described.
(Polar alicyclic hydrocarbon resin)
The alicyclic hydrocarbon resin having polarity that can be used in the present invention is obtained by introducing a polar group such as a hydroxyl group into a known alicyclic saturated hydrocarbon resin.

  The alicyclic saturated hydrocarbon resin can be easily obtained by hydrogenating a hydrocarbon resin having an aromatic ring using a catalyst, and by introducing a polar group into the cyclic saturated hydrocarbon group portion. The alicyclic hydrocarbon resin having polarity according to the present invention can be obtained. Examples of polar groups include phenolic hydroxyl groups, alcoholic hydroxyl groups, and carboxy groups.

  The amount of the polar group to be introduced is preferably 2 to 400 as a hydroxyl value (mgKOH / g), and more preferably 10 to 300 as a hydroxyl value. The amount of polar groups present in the petroleum resin can be measured by the method described in JIS K 0070.

  Since the specific hydrocarbon resin does not have a double bond in its structure, the stability, particularly heat stability, is good. In addition, by introducing a polar group such as a hydroxyl group, an excellent hysteresis loss improvement effect can be obtained even with a small amount of addition, so that an increase in hysteresis loss and an improvement in rupture properties are suppressed while suppressing an undesirable increase in tackiness. It is considered that an effect can be obtained. Further, even when a resin having a low softening point is used due to the function of the high polar group, there is an advantage that a sufficient hysteresis loss increasing effect can be obtained.

  The weight average molecular weight (Mw) of the alicyclic hydrocarbon resin having a polar group is preferably 300 to 4000, and more preferably 500 to 3000. When the molecular weight is within this range, sufficiently high attenuation performance can be obtained.

The specific hydrocarbon resin is preferably contained in an amount of 2 to 60 parts by mass, and 5 to 40 parts by mass per 100 parts by mass of the rubber component (in the case where two or more kinds are contained). Is preferred. The addition effect can be made practical by containing 2 to 60 parts by mass.
The content of the specific hydrocarbon resin, the measurement of the weight average molecular weight, and the detection of the polar group can be performed by a known method.

(Rubber component)
The rubber component may be a single rubber component, but a plurality of rubber components may be used in combination. Specifically, natural rubber (NR), styrene butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), chloroprene rubber, butyl rubber (IIR), halogenated butyl rubber, ethylene-propylene rubber (EPR, EPDM) ), Fluorine rubber, silicone rubber, urethane rubber and the like. Of these, natural rubber or a blend of natural rubber and a rubber other than natural rubber and containing 30% by mass or more of NR is preferable from the viewpoint of the mechanical properties of the vulcanized rubber. Although natural rubber is nonpolar, since the specific hydrocarbon resin has polarity, workability can be further improved while maintaining good hysteresis loss.

(Other ingredients)
The high damping rubber composition of the present invention may contain a compounding agent blended and used in a normal rubber composition together with the above components. For example, carbon black, silica, silane coupling agent, sulfur as vulcanizing agent, vulcanization accelerator, vulcanization acceleration aid, various process oils, zinc white, stearic acid, various softeners and resins, wax, aging The various compounding agents generally mix | blended, such as various fillers, such as an inhibitor, petroleum hydrocarbon, rosin, clay, and calcium carbonate, can be mentioned.

  For example, as the vulcanization accelerator, thiurams such as TMTD (tetramethyl disulfide) and dithiocarbamates such as EZ (zinc diethyldithiocarbamate) can be used.

  In combination with these, organic peroxides, quinonedioximes, polyfunctional acrylic monomers (for example, trimethylolethane triacrylate (TMETA), trimethylolpropane triacrylate (TMPTA), dipentaerythritol ether hexaacrylate (DPEHA) ), Pentaerythritol tetraacrylate (DPEHA), dimethylolpropane diacrylate (TMPTA), stearyl acrylate (SA), etc.) and triazine thiol can be used.

Furthermore, as sulfur-based vulcanizing agents and vulcanization accelerators, powder sulfur, highly dispersible sulfur, insoluble sulfur, etc., sulfur generally used as a vulcanizing agent for rubber, tetramethylthiuram disulfide, tetraethylthiuram disulfide, Tetrabutyl thiuram disulfide, tetramethyl thiuram monosulfide, thiurams such as dipentamethylene thiuram tetrasulfide, pentamethylene dithiocarbamate piperidine salt, pipecolyl dithiocarbamate pipecoline salt, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, dibutyldithiocarbamate Zinc, zinc N-ethyl-N-phenyldithiocarbamate, zinc N-pentamethylenedithiocarbamate, zinc dibenzyldithiocarbamate, sodium dimethyldithiocarbamate Diethylcarbamate such as sodium diethyldithiocarbamate, sodium dibutyldithiocarbamate, copper dimethyldithiocarbamate, ferric dimethyldithiocarbamate, tellurium diethyldithiocarbamate, zinc butylxanthate, zinc isopropylxanthate, xanthate such as sodium isopropylxanthate Salts, N-cyclohexyl-2-benzothiazole sulfenamide, Nt-butyl-2-benzothiazole sulfenamide, N-oxydiethylene-2-benzothiazole sulfenamide, N, N-diisopropyl-2-benzo List sulfenamides such as thiazole sulfenamide, and thiazoles such as 2-mercaptobenzothiazole and dibenzothiazyl disulfide. It can be. These can be used in combination.
The amount used is preferably 0.5 to 10.0 parts by mass and more preferably 1.0 to 6.0 parts by mass with respect to 100 parts by mass of the rubber component.

Examples of the carbon black to be used include standard varieties such as SAF, ISAF, HAF, FEF, GPF, SRF (rubber furnace) and MT carbon black (pyrolytic carbon).
The amount used is preferably 20 to 70 parts by mass and more preferably 25 to 65 parts by mass with respect to 100 parts by mass of the rubber component. In addition to carbon black, a plasticizer such as dioctyl sebacate may be added.

  A known anti-aging agent can also be selected and used for the anti-aging agent. For example, N-phenyl-N ′-(1,3-dimethylbutyl) -p-phenylenediamine (6C), N-phenyl-N′-isopropyl-p-phenylenediamine (3C), 2,2,4-trimethyl -1,2-dihydroquinoline polymer (RD) and the like. These can use about 0.5-5 weight part with respect to 100 weight part of rubber components.

  The high damping rubber composition of the present invention as described above can be produced by kneading the above-described components using a kneading apparatus such as a Banbury mixer, a roll, or a kneader that is usually used in the rubber industry. .

  The high-damping rubber composition of the present invention can be molded into various shapes such as a sheet, a rectangular parallelepiped, a rectangle, a polygon, a cylinder, and a sphere. It is also possible to use it by forming it into a sheet and punching it out. Depending on the purpose of use, it may be irregularly shaped. In particular, in the case of a high-damping rubber composition for a seismic isolation structure, it is generally a sheet.

  A plurality of high damping rubber compositions (rubber sheets) molded into a sheet shape are laminated to obtain a seismic isolation structure with a rubber laminate.

  Hysteresis loss of a rubber laminate used for a seismic isolation structure can be evaluated using an equivalent damping coefficient (HEQ) at 100% strain. The equivalent damping coefficient in the seismic isolation structure is preferably 0.10 to 0.50, and more preferably 0.18 to 0.23. If the equivalent damping coefficient is less than 0.10, the energy absorption capacity of the seismic isolation structure cannot be obtained sufficiently, and if it exceeds 0.50, it may be difficult to manufacture the seismic isolation structure. The equivalent attenuation coefficient can be measured by a known method.

  The high-damping rubber composition of the present invention and the rubber laminate obtained from the high-damping rubber composition are effectively used for seismic isolation structures mainly in support parts such as high-rise buildings, houses, road bridges and bridges. At the same time, it can also be used for applications such as vibration isolation devices in experimental devices. Moreover, it is applicable also to buffer materials, such as a cable-stayed bridge cable.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these Examples.

[Examples 1 to 9, Reference Example 10 and Comparative Examples 1 to 10]
The components shown in Table 1 and Table 2 below were kneaded with a Banbury mixer to produce a highly attenuated rubber composition. The obtained highly attenuated rubber composition was rolled to a thickness of 2 mm using a roll for rubber rolling to produce a rubber sheet.

The following products were used as the components in Tables 1 and 2 above.
"Rubber component" [Natural rubber: RSS # 4]
"Inorganic filler" [Carbon black: Asahi # 80-N (Asahi Carbon Co., Ltd.)]
"Hardened fatty acid" [LUNACRA (manufactured by Kao Corporation)]
"Vulcanization accelerator" [Zinc flower II: No. 3 zinc flower (manufactured by Hakusui Chemical Co., Ltd.)]
“Petroleum hydrocarbons” [Protowax 1 (manufactured by Nippon Oil Corporation)]
“Anti-aging agent” [described as anti-aging agent 6C. ANTIGENE 6C (manufactured by Sumitomo Chemical Co., Ltd.)]
"Heavy Aroma Oil" [Diana Process Oil AH-58 (manufactured by Idemitsu Kosan Co., Ltd.)]
"Crosslinking agent" [Zinc flower mixed sulfur: Z sulfur (manufactured by Tsurumi Chemical Co., Ltd.)]
“Accelerator” [described as accelerator CZ. Noxeller CZ (Ouchi Shinsei Chemical Co., Ltd.)]

"Specific hydrocarbon resin 1" [Hydroxyl-introduced alicyclic saturated hydrocarbon resin, KR1840 (manufactured by Arakawa Chemical Industries, Ltd.): softening point 90 ° C]
"Specific hydrocarbon resin 2" [Hydroxyl-introduced alicyclic saturated hydrocarbon resin, KR1842 (Arakawa Chemical Industries, Ltd.): softening point 120 ° C]
“Specific hydrocarbon resin 3” [alicyclic dicyclopentadiene resin, quinton 1700 (manufactured by Nippon Zeon Co., Ltd.): softening point 100 ° C.]
"Comparative hydrocarbon resin 1" [Alicyclic hydrocarbon resin Alcon P90 (Arakawa Chemical Industries, Ltd.): softening point 90 ° C]
"Comparative hydrocarbon resin 2" [alicyclic dicyclopentadiene resin (manufactured by Nippon Zeon Co., Ltd.): softening point 99 ° C]
“Comparative hydrocarbon resin 3” [aliphatic hydrocarbon / aromatic hydrocarbon copolymer D100 (manufactured by ZEON Corporation): softening point 99 ° C.]
“Comparative hydrocarbon resin 4” [Nisseki Neopolymer L90 (manufactured by Nippon Petrochemical Co., Ltd.): softening point 95 ° C.]
“Comparative hydrocarbon resin 5” [Nisseki Neopolymer L140 (manufactured by Nippon Petrochemical Co., Ltd.): softening point 145 ° C.]

[Evaluation]
About the rubber sheet of an Example and a comparative example, hardness (Hd), elongation at break (Eb), tensile strength (Tb), shear elastic modulus (G), and equivalent damping coefficient (Heq) were measured as follows. . In addition, the shear elastic modulus (G) and the equivalent damping coefficient (Heq) were obtained by performing longitudinal spring measurement and transverse spring measurement. The results are shown in Table 2 below.

(1) Hardness (Hd): Hardness was determined based on JIS K 6301.

(2) Elongation at break (Eb): Elongation at break was determined according to JIS K 6301.

(3) Tensile strength (Tb): Tensile strength was determined according to JIS K 6301.

(4) Shear elastic modulus (G) and equivalent damping coefficient (Heq):
[Preparation of shear elastic modulus measurement sample]
One rectangular rubber sheet 20 was produced by punching a rubber sheet into a 25 mm × 25 mm square, and this was sandwiched between two iron plates 22 each having a size of 25 mm × 60 mm × 2.3 mm. That is, as shown in FIG. A rubber sheet 20 was sandwiched between two iron plates 22 coated with an adhesive so as to have a crank shape in cross section. Thus, vulcanization was performed in a state where the iron plate 22 and the surface of the rubber sheet 3 in contact with the iron plate 22 were bonded, and the iron plate 22 and the rubber sheet surface were bonded. As a result, a sample having the shape shown in FIG.

[Measurement of shear modulus]
The sample was placed in a spring stiffness / loss energy measuring device (manufactured by Kakinomiya Seisakusho, model: EFH-26-8-10). The above two steel plates (FIG. 2 (B)) were applied to the outer side and the inner side with respect to the rubber sheet by changing the shear rate in the order of the following first and second times at a frequency of 0.2 Hz. At the same shear rate, a shear force was applied three times.

1st: 50% → 100% → 200% → 300%
Second time: 50%-100%->200%-> 300%
Then, at each shear rate, the measured value when the first force is applied (third time) and the measured value when the second force is applied (third time) are averaged, and G and HEQ are Calculated.

  In Tables 3 and 4, “G” means the shear elastic modulus (when the shear rate is 50%, 100%, 200%, 300%) (sometimes referred to as equivalent spring stiffness). “Heq” is an equivalent attenuation coefficient and is an index of the magnitude of hysteresis loss.

  From the results of Tables 3 and 4, it was found that the rubber sheet made of the high damping rubber composition of the example had a larger hysteresis loss than the comparative example and was practically superior. The workability was also good.

It is the schematic which shows the structure of the sample for a shear modulus measurement of a rubber composition, (A) shows the state which pinches | interposes a rubber sheet, (B) shows the state which adhere | attached the rubber sheet.

Explanation of symbols

20 ... Rubber sheet 22 ... Iron plate

Claims (7)

A high-damping rubber composition comprising at least one selected from natural rubber, styrene-butadiene rubber, butadiene rubber, isoprene rubber, and chloroprene rubber, and a hydroxyl group-introduced alicyclic saturated hydrocarbon resin. 2. The high-damping rubber composition according to claim 1 , wherein the hydroxyl group-introduced alicyclic saturated hydrocarbon resin is a resin obtained by introducing a hydroxyl group into the ring structure of the alicyclic saturated hydrocarbon resin. The highly attenuated rubber composition according to claim 2 , wherein the hydroxyl group is a phenolic hydroxyl group or an alcoholic hydroxyl group. The highly attenuated rubber composition according to any one of claims 1 to 3 , wherein the hydroxyl value of the hydroxyl group-introduced alicyclic saturated hydrocarbon resin is 2 to 400 (mgKOH / g). . The high-damping rubber composition according to any one of claims 1 to 4 , wherein the hydroxyl group-introduced alicyclic saturated hydrocarbon resin has a weight average molecular weight of 300 to 4000. The hydroxyl group-introduced alicyclic saturated hydrocarbon resin is selected from a resin obtained by hydrogenating a petroleum resin having a hydroxyl group and a resin obtained by polymerizing a monomer having a hydroxyl group. The high damping rubber composition according to claim 5 . The high-attenuation according to any one of claims 1 to 6 , wherein the hydroxyl group-introduced alicyclic saturated hydrocarbon resin is contained in an amount of 2 to 60 parts by mass per 100 parts by mass of the rubber component. Rubber composition.