TW202311413A - Rubber composition for rubber bearing body side walls, and rubber bearing body using same - Google Patents

Abstract

The present invention provides: a rubber composition for rubber bearing body side walls, the rubber composition exhibiting high adhesion to a rubber bearing body, while exhibiting excellent performance in terms of low temperature properties, durability and weather resistance; and a rubber bearing body which uses this rubber composition for rubber bearing body side walls. The above are achieved by means of a rubber bearing body that is obtained by alternately stacking rubber layers 2 and hard plates 1 and arranging a lateral surface material 5, which is formed of a covering rubber, so as to surround the outer lateral surface of the rubber bearing body, wherein the lateral surface material 5 is formed of a crosslinked product of a rubber composition for rubber bearing body side walls, the rubber composition containing polymer components (A)-(C) described below. (A) A diene rubber that is mainly composed of at least one of a natural rubber and an isoprene rubber, provided that this diene rubber excludes an ethylene-propylene-diene ternary copolymer and a liquid rubber. (B) An ethylene-propylene-diene ternary copolymer that has a diene content of 10% by mass or more and an ethylene content of 55% by mass or less. (C) A liquid rubber that has a molecular weight of 1,000 to 60,000.

Description

Rubber composition for side wall of rubber supporting body and rubber supporting body using same

The present invention relates to a rubber composition for a side wall of a rubber support for forming a side wall of a rubber support having anti-vibration properties and vibration isolation properties, and a rubber support using the same.

In recent years, the progress of bridge technology has been astonishing and the scale of bridges has expanded year by year. Along with this, long-span bridges have been designed. The erection of the aforementioned long-span bridges is usually carried out by placing a plurality of rubber supports on bridge piers arranged at predetermined intervals and installing long-span girders on the aforementioned bridge piers through the supports. By interposing the rubber supporting body in this way, the aforementioned long-span bridge can effectively obtain functions such as anti-vibration support and shock-isolation support. However, the above-mentioned rubber supporting body bears an extremely large load, so in order to provide excellent load support, it is usually formed by alternately laminating and integrating rigid hard plates such as metal plates and rubber layers.

In addition, among the above-mentioned rubber supports, there are also those provided with a side member made of coated rubber so as to surround the outer surface thereof (for example, refer to Patent Documents 1 to 3). In addition, weather resistance (ozone resistance, etc.) is required for the above-mentioned covering rubber, so it is recommended to use ethylene-propylene-diene terpolymer (hereinafter, abbreviated as "EPDM") excellent in weather resistance as the polymer component. ). [Prior Technical Literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. 2009-001603 [Patent Document 2] Japanese Patent No. 5712735 [Patent Document 3] Japanese Patent No. 5735886

[Problem to be solved by the invention]

However, if EPDM is used in the polymer component of the aforementioned coating rubber, the following problems are likely to occur: the adhesion of the aforementioned coating rubber to the rubber support (body) becomes poor; It becomes hard and does not function in cold regions, etc. (low temperature resistance becomes poor); the durability (tensile strength) of the aforementioned coating rubber becomes poor when it is greatly deformed, etc. Therefore, there is a need to maintain the weather resistance obtained by EPDM and solve the aforementioned problems.

The present invention is made in view of such circumstances, and provides a rubber composition for a side wall of a rubber support body and a rubber support body using the same, which can exhibit high adhesiveness to a rubber support body and exhibit excellent performance in low temperature resistance, durability, and weather resistance. [Means to solve the problem]

In view of the foregoing, the inventors of the present case have studied the use of natural rubber, isoprene, and Diene rubber as the main component, and liquid rubber. Furthermore, it has been found that using EPDM whose diene content and ethylene content show a specific range for the aforementioned EPDM, and using a liquid rubber whose molecular weight shows a specific range for the aforementioned liquid rubber, can play a role in supporting the rubber support. (Body) exhibits high adhesiveness, low temperature resistance, durability, and weather resistance. By adopting the above-mentioned constitution, it is possible to provide a rubber composition for a side wall of a rubber support body and a rubber support body using the same, which can exhibit high adhesiveness to the rubber support body and exhibit excellent performance in low temperature resistance, durability, and weather resistance , the reason for which is considered to be as follows. That is, it is considered that in the present invention, by adjusting the diene content of EPDM within a specific range so as to be higher than the usual amount, and combining the above-mentioned EPDM with natural rubber and isoprene rubber as main components When diene-based rubbers are used together, the amount of diene which is the starting point of the adhesive reaction increases, so that the adhesiveness can be improved. Also, in the present invention, it is considered that by adjusting the ethylene content of EPDM within a specific range so as to be lower than the usual amount, the crystallinity is lowered and the aforementioned low-temperature properties can be improved. In addition, it is considered that if the ethylene content of EPDM is lowered as described above, the durability will generally be lowered, but in the present invention, reinforcement is obtained by using a liquid rubber showing a specific molecular weight, so the aforementioned reduction in ethylene content is accompanied by Durability reduction has been suppressed. Furthermore, the aforementioned liquid rubber has a good affinity with EPDM and also functions as a softener, and its molecular weight is higher than that of a commonly used softener (processing oil; process oil). Sex has contributors.

That is, the present invention provides the following [1] to [4]. [1] A rubber composition for a side wall of a rubber support, comprising the following (A) to (C) as polymer components; (A) Diene-based rubber mainly composed of at least one of natural rubber and isoprene rubber; however, EPDM and liquid rubber are not included; (B) EPDM with a diene content of 10% by mass or more and an ethylene content of 55% by mass or less; (C) Liquid rubber having a molecular weight of 1,000 to 60,000. [2] The rubber composition for the side wall of a rubber support according to [1], wherein (A) and (B) are in a ratio of (A)/(B)=50/50 to 90/10 in terms of mass ratio . [3] The rubber composition for a rubber support side wall according to [1] or [2], wherein the (C) is 5 to 30 parts by mass relative to 100 parts by mass of the total amount of (A) and (B) ratio. [4] A rubber supporting body obtained by laminating rubber and hard boards alternately, the rubber supporting body has a side material formed by covering the outer surface of the rubber supporting body, and the covering rubber is composed of such as [1 ] to [3], the side wall of the rubber support body is composed of a cross-linked rubber composition. [Effect of the invention]

Based on the above, the rubber composition for the side wall of the rubber support of the present invention is used as a material for the side material formed to surround the outer side of the rubber support, thereby exhibiting high adhesion to the rubber support and low temperature performance. Excellent performance in durability and weather resistance.

Embodiments of the present invention will be described in detail below.

The rubber composition for a rubber support body side wall of the present invention (hereinafter, simply referred to as "this rubber composition") contains the following (A) to (C) as polymer components. In addition, the aforementioned rubber composition preferably contains only the following (A) to (C) as polymer components, but it may also contain a small amount of other polymer components as necessary. (A) Diene-based rubber mainly composed of at least one of natural rubber and isoprene rubber (but EPDM and liquid rubber are not included). (B) EPDM having a diene content of 10% by mass or more and an ethylene content of 55% by mass or less. (C) Liquid rubber having a molecular weight of 1,000 to 60,000.

The details of each component in the aforementioned rubber composition will be described below. In addition, "X and/or Y (X, Y are arbitrary configurations)" in this specification means at least one of X and Y, and means only X, only Y, and X and Y.

"Diene Rubber (A)" As the diene rubber (A), a diene rubber mainly composed of at least one of natural rubber (NR) and isoprene rubber (IR) (NR and/or IR) is used. In addition, the "main component" used in the present invention usually means that it accounts for 55% by mass or more in the diene rubber (A), preferably it means that it accounts for 60% by mass or more in the diene rubber (A). , more preferably means that it accounts for 70% by mass or more in the diene rubber (A), and more preferably means that it accounts for 100% by mass in the diene rubber (A).

In addition, as the above-mentioned diene rubber (A), in addition to the above-mentioned main component, butadiene rubber (BR), styrene-butadiene rubber (SBR), acrylonitrile-butadiene Rubber (NBR), chloroprene rubber (CR), butyl rubber (IIR), etc. are used alone or in combination of two or more.

In addition, in the present invention, it is specified that the diene rubber (A) does not include EPDM (ethylene-propylene-diene terpolymer) and liquid rubber. In addition, the term "liquid rubber" in the present invention refers to rubber that exhibits a viscosity of 1500 Pa･s or less at normal temperature (23°C). The aforementioned viscosity can be measured using a B-type viscometer, for example.

"Specific EPDM (B)" In the aforementioned specific EPDM (B), EPDM having a diene content of 10% by mass or more is used from the viewpoint of obtaining desired adhesiveness and the like. From the same point of view, the aforementioned diene content is preferably at least 12% by mass, more preferably at least 14% by mass. In addition, if the content of the aforementioned diene is too small, desired adhesiveness cannot be obtained and peeling may occur. Moreover, the upper limit of the said diene content is normally 20 mass %, Preferably it is 18 mass %, More preferably, it is 16 mass %. In addition, in the aforementioned specific EPDM (B), EPDM having an ethylene content of 55% by mass or less is used from the viewpoint of obtaining desired low-temperature properties. Considering the same point of view, the aforementioned ethylene content is preferably less than 48% by mass, more preferably less than 45% by mass, and most preferably less than 43% by mass. Moreover, when the said ethylene content is too much, desired low temperature property etc. cannot be acquired. Also, the lower limit of the aforementioned ethylene content is usually 30% by mass, preferably 35% by mass, more preferably 40% by mass. The diene monomer used as the third component constituting the aforementioned specific EPDM (B) is preferably a diene monomer having 5 to 20 carbon atoms. Specifically, 1,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene, 2,5-dimethyl-1,5-hexadiene, 1,4- Octadiene, 1,4-cyclohexadiene, cyclooctadiene, dicyclopentadiene (DCP), 5-ethylidene-2-norcamphene (ENB), 5-butylene-2-norcamphene ene, 2-methylallyl-5-norcamphene, 2-isopropenyl-5-norcamphene, etc. These can be used individually or in combination of 2 or more types. Among these diene-based monomers (third component), dicyclopentadiene (DCP) and 5-ethylidene-2-norbornene (ENB) are preferable.

Moreover, in this rubber composition, if the aforementioned (A) and (B) are in the ratio of (A)/(B)=50/50 to 90/10 by mass ratio, the desired weather resistance and adhesion can be obtained. The point of view of sex and so on is better. Considering the same point of view, the ratio of (A)/(B)=60/40-80/20 is more preferable, and the ratio of (A)/(B)=65/35-70/30 is particularly preferable.

<<Specific Liquid Rubber (C)>> As the specific liquid rubber (C), liquid rubber having a molecular weight of 1,000 to 60,000 is used from the viewpoint of obtaining desired durability and the like. Considering the same point of view, the molecular weight of the aforementioned liquid rubber is preferably 10,000-55,000, more preferably 25,000-50,000. In addition, regarding the molecular weight of the aforementioned liquid rubber (C), the higher value represents the value of the weight average molecular weight (Mw) (the same applies to the users in the examples described later). Here, the aforementioned weight average molecular weight (Mw) is the weight average molecular weight obtained by converting the molecular weight of standard polystyrene. (Detector)") Use 3 columns in series: Shodex GPC KF-806L (exclusion limit molecular weight: 2×10 ⁷ , separation range: 100～2×10 ⁷ , theoretical plate number: 10,000 plates/root, filler material : Styrene-divinylbenzene copolymer, filler particle size: 10 μm).

The aforementioned specific liquid rubber (C) is a rubber having the aforementioned molecular weight and a viscosity of 1500 Pa･s or less at normal temperature (23° C.). Specifically, liquid isoprene (liquid IR), liquid butadiene (liquid BR), liquid isoprene-butadiene block copolymer (liquid IR-BR) , liquid styrene butadiene (liquid SBR), liquid ethylene propylene rubber (liquid EPM), liquid EPDM, liquid acrylonitrile-butadiene rubber (liquid NBR), liquid hydrogenated acrylonitrile- Butadiene rubber (liquid H-NBR), etc. These can be used individually or in combination of 2 or more types. Among them, a liquid isoprene-butadiene block copolymer (liquid IR-BR) is preferable.

Furthermore, in this rubber composition, if the ratio of the aforementioned (C) is 5 to 30 parts by mass relative to 100 parts by mass of the total amount of the aforementioned (A) and (B), it is relatively difficult from the viewpoint of obtaining desired durability, etc. good. Considering the same point of view, in this rubber composition, the ratio of the aforementioned (C) is preferably 10 to 25 mass parts, more preferably 15 to 20 mass parts relative to 100 mass parts of the total amount of the aforementioned (A) and (B). share.

In this rubber composition, carbon black, silica and other fillers, crosslinking agents, diene rubber (A) with NR and/or IR as main components, specific EPDM (B), A specific liquid rubber (C) is blended together. In addition, in this rubber composition, vulcanization accelerators, vulcanization aids, anti-aging agents, softeners, etc. may be blended as necessary. In addition, in this rubber composition, the aforementioned specific liquid rubber (C) functions as a softener, so it is preferable not to contain a softener.

"Carbon Black" As the aforementioned carbon black, for example, carbon blacks of various grades such as SAF grade, ISAF grade, HAF grade, MAF grade, FEF grade, GPF grade, SRF grade, FT grade, and MT grade can be used. These can be used individually or in combination of 2 or more types. Among them, considering mechanical strength and elongation at break, etc., it is preferable to use SAF grade carbon black.

In this rubber composition, when the content of the aforementioned carbon black is 20 to 60 parts by mass relative to 100 parts by mass of the total amount of the aforementioned (A) and (B), it is preferable from the viewpoint of mechanical strength and elongation at break, etc. . Considering the same point of view, in this rubber composition, the ratio of the aforementioned carbon black is preferably a ratio of 30 to 50 parts by mass, more preferably 35 to 45 parts by mass, relative to 100 parts by mass of the total amount of (A) and (B). The ratio of parts by mass. In addition, if the content of the aforementioned carbon black is too small, it tends not to be able to obtain the desired reinforcing properties; conversely, if the content of the aforementioned carbon black is too large, it tends to be observed that the scorch resistance deteriorates and the elongation decreases.

"Crosslinking agent" Examples of the aforementioned crosslinking agent include sulfur-based vulcanizing agents such as sulfur and sulfur chloride, 2,4-dichlorobenzoyl peroxide, benzoyl peroxide, 1,1-di-tert-butyl peroxide, etc. Oxy-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-dibenzoylperoxyhexane, 4,4'-di-tert-butylperoxy n-butyl valerate, dicumyl peroxide, tert-butyl peroxybenzoate, di-tert-butyl dicumyl peroxide, tert-butyl cumyl peroxide, 2,5 -Dimethyl-2,5-di-tert-butyl peroxyhexane, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di-tert-butyl peroxy- Peroxide vulcanizing agents such as 3-hexyne and 1,3-bis(tert-butylperoxyisopropyl)benzene. These can be used individually or in combination of 2 or more types. Among them, sulfur and dicumyl peroxide are preferably used.

In this rubber composition, if the content of the aforementioned crosslinking agent is 0.5 to 3.0 parts by mass relative to 100 parts by mass of the total amount of (A) and (B) mentioned above, it is comparatively low from the viewpoint of obtaining desired durability, etc. good. Considering the same point of view, in this rubber composition, the ratio of the aforementioned crosslinking agent is preferably 0.75 to 2.5 parts by mass, more preferably 1.0 to 100 parts by mass of the total amount of (A) and (B). 2.0 parts by mass. In addition, if the content of the above-mentioned crosslinking agent is too small, a tendency to decrease in tensile strength and the like will be observed; conversely, if the content of the above-mentioned crosslinking agent is too large, a tendency to deteriorate the scorch resistance and decrease the elongation will be observed.

"Vulcanization Accelerator" Examples of the vulcanization accelerator include thiazole-based, sulfenamide-based, thiuram-based, aldehyde-ammonium-based, aldehyde-amine-based, guanidine-based, and thiourea-based vulcanization accelerators. These can be used individually or in combination of 2 or more types. Among them, a sulfenamide-based vulcanization accelerator is preferable from the viewpoint of excellent crosslinking reactivity.

In this rubber composition, the content of the vulcanization accelerator is preferably in a ratio of 0.5 to 2.5 parts by mass, more preferably in the range of 1.0 to 2.0 parts by mass, relative to 100 parts by mass of the total amount of (A) and (B) above. .

The aforementioned thiazole-based vulcanization accelerators include, for example, dibenzothiazole disulfide (MBTS), 2-mercaptobenzothiazole (MBT), 2-mercaptobenzothiazole sodium salt (NaMBT), and 2-mercaptobenzothiazole zinc salt. (ZnMBT) and so on. These can be used individually or in combination of 2 or more types.

The aforementioned sulfenamide-based vulcanization accelerators include, for example, N-oxydiethylene-2-benzothiazolylsulfenamide (NOBS), N-cyclohexyl-2-benzothiazolylsulfenamide Amine (CBS), N-tert-butyl-2-benzothiazolylsulfenamide (BBS), N,N'-dicyclohexyl-2-benzothiazolylsulfenamide, etc. These can be used individually or in combination of 2 or more types.

The aforementioned thiuram-based vulcanization accelerators include, for example, tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide (TETD), tetrabutylthiuram disulfide (TBTD), Tetrabenzylthiuram (2-ethylhexyl)thiuram (TOT), tetrabenzylthiuram disulfide (TBzTD), etc. These can be used individually or in combination of 2 or more types.

"Vulcanization Auxiliary" Examples of the aforementioned vulcanization aids include stearic acid, magnesium oxide, zinc oxide, and the like. These can be used individually or in combination of 2 or more types.

In this rubber composition, the content of the vulcanization aid is preferably in a ratio of 0.1 to 10 parts by mass, more preferably in the range of 0.3 to 7 parts by mass, relative to 100 parts by mass of the total amount of (A) and (B) above. .

"Anti-aging agent" The aforementioned antiaging agents include, for example, urethane-based antiaging agents, phenylenediamine-based antiaging agents, phenol-based antiaging agents, diphenylamine-based antiaging agents, quinoline-based antiaging agents, and imidazole-based antiaging agents. , waxes, etc. These can be used individually or in combination of 2 or more types.

In this rubber composition, the content of the anti-aging agent is preferably in a ratio of 0.5 to 15 parts by mass, more preferably in the range of 1 to 10 parts by mass, relative to 100 parts by mass of the total amount of (A) and (B) above. .

"Softener" Examples of the softening agent (processing oil) include naphthenic oils, paraffinic oils, aromatic oils, and the like. These can be used individually or in combination of 2 or more types.

In this rubber composition, the content of the softener is preferably in a ratio of 0 to 20 parts by mass, more preferably in the range of 0 to 10 parts by mass, relative to 100 parts by mass of the total amount of (A) and (B). In addition, as mentioned above, in this rubber composition, the above-mentioned specific liquid rubber (C) exhibits a function as a softener, so even if no softener is contained, desired performance can still be exhibited.

Here, the present rubber composition can be prepared by blending the aforementioned components and kneading them using a kneader such as a kneader, Banbury mixer, or roll.

The rubber composition is a rubber composition specially used to form the side wall of a rubber support with anti-vibration and shock-isolation properties. Furthermore, the present rubber composition is preferably used as a side wall material of a large support such as a bridge support or a building support.

A seismic isolation support for a bridge or a building is, for example, obtained by laminating and integrating hard plates 1 and rubber layers 2 alternately as shown in FIG. to surround its outer sides. In the rubber supporting body (hereinafter, simply referred to as "this rubber supporting body") as one embodiment of the present invention, the side material 5 is composed of a cross-linked body of this rubber composition. In addition, the upper mounting plate 3 and the lower mounting plate 4 shown in the figure are metal mounting plates, which are bonded and fixed to the upper and lower parts of the laminated body of the hard plate 1 and the rubber layer 2 . Furthermore, in the aforementioned seismic isolation support, the lower mounting plate 4 is fixed to a lower structure such as a bridge pier, and the upper mounting plate 3 is fixed to an upper structure such as a bridge truss.

As the aforementioned hard board 1 , for example, metal plates such as rolled steel plates and iron plates, hard plastic boards, and the like can be used.

In addition, the rubber composition used as the material of the rubber layer 2 contains diene rubber such as NR, IR, etc. as a polymer component and contains a vulcanizing agent. In addition, carbon black, a softener, an antiaging agent, a processing aid, a vulcanization accelerator, a white filler, a reactive monomer, a foaming agent, and the like may be appropriately blended in the aforementioned rubber composition as necessary. Furthermore, the aforementioned rubber composition can be prepared by kneading a mixture of the aforementioned materials using a kneader such as a kneader, Banbury mixer, open roll, twin-shaft screw mixer, or the like.

Here, this rubber support body (refer FIG. 1) is produced as follows, for example. That is, first, a rubber composition as a material for the rubber layer 2 is prepared in the aforementioned manner. Next, a plurality of hard boards 1 of a predetermined size are prepared, and the upper mounting board 3 and the lower mounting board 4 are also prepared. Then, on the lower mounting plate 4, unvulcanized rubber sheets and hard boards 1 are alternately stacked. , to overlap the upper mounting plate 3, thereby producing a laminated body (rubber support body). In addition, an adhesive may be pre-coated on the lamination surface of the aforementioned hard board 1 or the like. Next, the present rubber composition obtained in the above-mentioned manner was shaped into a sheet to produce an unvulcanized rubber sheet. The above-mentioned unvulcanized rubber sheet is in a state where it is semi-crosslinked to the degree of incomplete crosslinking (the degree to which vulcanization adhesiveness can be obtained), and its forming conditions will vary depending on the thickness, but it is usually heated at 130-180°C for 1 ~30 minutes and make it semi-cross-linked. Next, after covering the above-mentioned unvulcanized rubber sheet so as to surround the outer side of the above-mentioned laminated body (rubber support), this is placed in a predetermined mold, and the above-mentioned unvulcanized rubber sheet is heated at 130 to 180°C for 1 Cross-linking is carried out for ~24 hours, and it is vulcanized and adhered to the rubber support, whereby a rubber support (the present rubber support) having the side sheet 5 composed of the present rubber composition can be manufactured. In addition, the above-mentioned laminated body (rubber support body) can also be set in a molding die by placing the hard plate 1, the upper mounting plate 3, and the lower mounting plate 4 in a predetermined arrangement, and the rubber The rubber composition of the layer 2 material is injected into the cavity in the molding die by injection molding, etc., heated and vulcanized, and then released from the mold.

Moreover, this rubber support body can also be manufactured as follows. That is, after using a rubber composition as a material for the rubber layer 2 and molding it into a rubber sheet (rubber layer 2) of a predetermined thickness by extrusion molding, etc., it is bonded to a predetermined hard surface with an appropriate adhesive. Plates 1 are alternately stacked and bonded to form a rubber block, and further, upper mounting plates 3 and lower mounting plates 4 are bonded and integrated on the upper and lower surfaces thereof as necessary. For the outer side of the rubber support obtained in this way, the side material 5 is formed in the above-mentioned manner, whereby the present rubber support can be manufactured.

In addition, the side material 5 can also be formed by setting the aforementioned rubber support in a predetermined mold, and then injecting the present rubber composition between the outer peripheral surface of the aforementioned rubber support and the inner peripheral surface of the mold by injection molding, etc. It is formed by cross-linking the present rubber composition. The heating conditions during the aforementioned crosslinking are compared with the aforementioned manufacturing method. However, the step of semi-crosslinking as in the aforementioned production method is not necessary, and it is sufficient to directly heat to make it crosslinked.

The dimensions of the present rubber support obtained in this manner are, for example, an outer diameter of about 20 to 200 cm, and a total thickness of the present rubber support of about 10 to 80 cm. In addition, the thickness of each layer constituting the present rubber support should be within the range that can fully achieve the intended function of each layer. For example, the thickness of the hard board 1 is about 0.1 to 2 cm per layer, and the thickness of the rubber layer 2 is 1 cm. The layer is about 0.5-7 cm, and the thickness of the side material 5 is about 0.5-10 cm. In addition, the number of laminations of the hard plate 1 and the rubber layer 2 in the present rubber support can also be appropriately set according to the application of the vibration-insulating laminate.

In addition, the outer shape of the rubber support body can be cylindrical, elliptical cylindrical, angular cylindrical, etc., and can be appropriately set according to its application. [Example]

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

First, prior to Examples and Comparative Examples, the materials (polymer components and softeners) shown below were prepared.

[NR] natural rubber

[IR] Made by Zeon Corporation, Japan, product name: Nipol IR2200

[EPDM(i)] Mitsui Chemicals Co., Ltd. product name: Mitsui EPT 9090M (ethylene content: 41% by mass, diene content: 14% by mass)

[EPDM(ii)] Made by JSR Corporation, product name: EP331 (ethylene content: 47% by mass, diene content: 11.3% by mass)

[EPDM(iii)] Sumitomo Chemical Co., Ltd. product name: ESPRENE 505 (ethylene content: 50% by mass, diene content: 10% by mass)

[EPDM(iv)] Mitsui Chemicals Co., Ltd. product name: Mitsui EPT 8030M (ethylene content: 47% by mass, diene content: 9.5% by mass)

[EPDM(v)] Made by LANXESS, product name: Keltan K3960Q (ethylene content: 56% by mass, diene content: 11.4% by mass)

[Liquid rubber (i)] Made by Kuraray Corporation, product name: LIR-30 (weight average molecular weight: 28000)

[Liquid rubber (ii)] Made by Kuraray Corporation, product name: LIR-50 (weight average molecular weight: 54000)

[Liquid rubber (iii)] Made by EVONIK, product name: POLYVEST 110 (molecular weight: 1100)

[softener] Made by Japan Sun Oil Company, product name: Sunpar 110

[Examples 1-10, Comparative Examples 1-5] The aforementioned polymer components and softeners were blended in the following ratios shown in Table 1 and Table 2, and further added and blended 2 parts by mass of stearic acid (manufactured by NOF, product name: pearl stearic acid Sakura ), 5 parts by mass of zinc oxide (manufactured by Sakai Chemical Industry Co., Ltd., product name: Zinc Oxide II), 3 parts by mass of amine-based anti-aging agent (manufactured by Seiko Chemical Co., Ltd., product name: Ozonone 6C), 4 parts by mass of Wax (manufactured by Ouchi Shinko Chemical Co., Ltd., product name: Sunnoc), 35 parts by mass of SAF grade carbon black (manufactured by Tokai Carbon Co., Ltd., product name: Seast 9M), 1 part by mass of sulfenamide-based vulcanization accelerator ( Made by Ouchi Shinshin Chemical Co., Ltd., product name: Nocceler CZ-G), and 1 part by mass of sulfur (manufactured by Tsurumi Chemical Industry Co., Ltd., product name: Jinhuayin Micropowder Sulfur), and carried out using a Banbury mixer and an open roll Kneading was carried out to obtain a rubber composition (rubber composition for rubber support body side walls). Specifically, the components other than the vulcanizing agent and the vulcanization accelerator were kneaded for 5 minutes in a Banbury mixer, and discharged when the temperature reached 150°C to obtain a masterbatch, and then mixed in the masterbatch at the ratio shown in the table A vulcanizing agent and a vulcanization accelerator are blended, and these are kneaded with an open roll to obtain the aforementioned rubber composition.

Using the rubber compositions of Examples and Comparative Examples obtained in this manner, each characteristic was evaluated in accordance with the following criteria. The results are also shown in Table 1 and Table 2 below.

＜Tensile Strength＞ Using each of the obtained rubber compositions, press molding (vulcanization) was carried out under the conditions of 150° C.×20 minutes to obtain rubber sheets with a thickness of 2 mm. Then, JIS No. 5 dumbbells were punched out from the rubber sheet, and the tensile strength (tensile strength) in a 25° C. environment was measured in accordance with JIS K 6251. In addition, those with a tensile strength of 20 MPa or more were rated as "◎ (excellent)", those with a tensile strength of 15 MPa or more and less than 20 MPa were rated as "○ (very good)", and those with a tensile strength of 10 MPa or more and Those with less than 15 MPa were rated as "△ (good)", and those with tensile strength less than 10 MPa were rated as "× (poor)".

＜Low temperature resistance＞ Using each of the obtained rubber compositions, and using the vulcanization conditions of 150°C x 30 minutes, the cylindrical shear method with metal fittings stipulated in JIS K 6394 "Test methods for dynamic properties of vulcanized rubber and thermoplastic rubber" was prepared. test piece. Then, using the obtained test pieces, follow the "6. Dynamic property test using a large-scale test device" stipulated in JIS K 6394 (1998), at the test temperature: -30°C, 20°C, and the test vibration frequency: 0.5Hz , Strain amplitude (shear): Under the condition of 250%, the load/deflection curves were continuously measured 11 times respectively. Then, from the load/deflection curve obtained for 10 times from the second to the eleventh time, the equivalent rigidity at each measurement temperature: Keq (-30°C), Keq (20°C) was obtained. Using the obtained equivalent rigidity, calculate G (temperature dependence) from the following formula. Furthermore, those whose G was less than 1.5 were rated as "○ (very good)", those whose G was 1.5 or more and less than 1.6 were rated as "△ (good)", and those whose G was 1.6 or more were rated as "× (poor)". G(temperature dependence)=Keq(-30℃)/Keq(20℃)

＜Adhesiveness＞ Each obtained rubber composition was heated and vulcanized on an iron plate at 150° C. for 30 minutes (vulcanization bonding). Regarding the adhesion between the iron plate and rubber in the test piece obtained in this way, according to "5. 90-degree peel test between metal sheet and rubber" in JIS K 6256 "Adhesion test method for vulcanized rubber", Peel off the rubber that has been bonded to the iron plate along the direction of 90 degrees, and visually observe the state of the peeled part. In addition, the damage rate of the rubber part was 100% and rated as "○ (very good)", and the case where there was a part where the interface between the rubber part and the iron plate peeled was rated as "X (poor)".

＜Ozone Resistance＞ Using each of the obtained rubber compositions, press molding (vulcanization) was carried out under the conditions of 150° C.×20 minutes to obtain rubber sheets with a thickness of 2 mm. From this rubber sheet, a JIS1 number dumbbell shape was punched out to prepare a test piece. Then, according to JIS K 6259, the aforementioned test piece was put into an ozone tank with an ozone concentration of 200±20 pphm and a temperature of 40° C. in a state where a tensile strain of 80±2% was applied. After 672 hours from the introduction, the presence or absence of cracks in the test piece was visually observed, and those without cracks were rated as "○ (very good)", and those with cracks were rated as "× (poor)".

[Table 1]

[Table 2]

As can be seen from the results in Table 1 above, the rubber composition of the example can exhibit high adhesiveness due to crosslinking and excellent performance at low temperature, tensile strength (durability), and ozone resistance (weather resistance). The rubber composition system for the side wall of the rubber support body is excellent. Therefore, it is judged that the rubber composition of the example is excellent as a material for the side material of the seismic isolation support body for bridge use and building use as shown in FIG. 1 .

On the other hand, according to the results in Table 2, the rubber composition of Comparative Example 1 had inferior ozone resistance (weather resistance) compared to Examples because the polymer component was only natural rubber. The rubber composition of Comparative Example 2 has poorer adhesiveness than that of Examples because the EPDM has less diene content. The rubber composition of Comparative Example 3 has poorer low-temperature performance than that of Examples because the EPDM has a higher ethylene content. The rubber composition of Comparative Example 4 used a softener with a lower molecular weight (molecular weight less than 1000) than that of liquid rubber, so the tensile strength was inferior to that of Examples. Since the rubber composition of Comparative Example 5 does not contain liquid rubber and has a large ratio of EPDM, the results of tensile strength, low-temperature properties, and adhesiveness are inferior to those of Examples.

The specific forms of the present invention have been presented in the foregoing embodiments, but the foregoing embodiments are only examples and are not interpreted as limiting. Various modifications that are obvious to those skilled in the art to which the invention pertains are also included in the scope of the present invention. [Industrial Utilization]

The rubber composition for the side wall of the rubber support body of the present invention is a rubber composition specially used to form the side wall of the rubber support body with anti-vibration and shock-isolation properties. Moreover, this rubber composition is suitable for use as a material for the side walls of large supports such as bridge supports and building supports. In addition, it can also be used as vibration materials for automobiles, washing machines and other general home appliances. Shock dampers, etc.

1: hard board 2: rubber layer 3: Upper mounting plate 4: Lower mounting plate 5: side material

[Fig. 1] is a cross-sectional view showing an example of a seismic isolation support.

1: hard board

2: rubber layer

3: Upper mounting plate

4: Lower mounting plate

5: side material

Claims (4)

A rubber composition for the side wall of a rubber support body, using the following (A) to (C) as polymer components; (A) Diene rubber mainly composed of at least one of natural rubber and isoprene rubber; however, ethylene-propylene-diene terpolymer and liquid rubber are not included; (B) an ethylene-propylene-diene terpolymer with a diene content of 10% by mass or more and an ethylene content of 55% by mass or less; (C) Liquid rubber having a molecular weight of 1,000 to 60,000. The rubber composition for the side wall of a rubber support according to claim 1, wherein (A) and (B) are in a ratio of (A)/(B)=50/50 to 90/10 in terms of mass ratio. The rubber composition for a rubber support side wall according to claim 1 or 2, wherein the ratio of (C) is 5 to 30 parts by mass relative to 100 parts by mass of the total amount of (A) and (B). A rubber support body obtained by laminating rubber and hard boards alternately, The rubber supporting body has a side material covered with rubber to surround its outer side, and The covering rubber is composed of a cross-linked body of the rubber composition for the side wall of the rubber support according to any one of claims 1 to 3.

Images