CN116648483A

CN116648483A - Rubber composition for rubber support side wall and rubber support using the same

Info

Publication number: CN116648483A
Application number: CN202280007974.5A
Authority: CN
Inventors: 村谷圭市
Original assignee: Sumitomo Riko Co Ltd
Current assignee: Sumitomo Riko Co Ltd
Priority date: 2021-06-30
Filing date: 2022-06-28
Publication date: 2023-08-25
Also published as: WO2023276994A1; JP7217396B1; JPWO2023276994A1; TW202311413A

Abstract

The invention provides a rubber composition for a side wall of a rubber support, which has high adhesiveness to the rubber support and can exert excellent low-temperature performance, durability and weather resistance, and a rubber support using the composition. In a rubber support in which a side surface material 5 composed of a coated rubber is provided so as to surround the outer side surface of the rubber support in which rubber layers 2 and hard plates 1 are alternately laminated, the side surface material 5 is composed of a crosslinked rubber composition for the side wall of the rubber support, which contains the following (a) to (C) as polymer components. (A) Diene rubber containing at least one of natural rubber and isoprene rubber as a main component. However, no ethylene-propylene-diene terpolymer or liquid rubber is included. (B) An ethylene-propylene-diene terpolymer having a diene content of 10 mass% or more and an ethylene content of 55 mass% or less. (C) a liquid rubber having a molecular weight of 1000 to 60000.

Description

Rubber composition for rubber support side wall and rubber support using the same

Technical Field

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

Background

In recent years, the progress of bridge technology is remarkable, the bridge scale is increased year by year, and a long bridge is designed accordingly. The long bridge is usually erected by providing a plurality of rubber supports on bridge columns arranged at predetermined intervals, and providing long span bridge girders on the bridge columns via the supports. By sandwiching the rubber support in this manner, the function of vibration-proof support, and the like can be effectively obtained in the long bridge. However, since the rubber support is extremely loaded with a large load, in order to provide excellent load support, a rigid hard plate such as a metal plate and a rubber layer are generally laminated alternately and integrated.

Further, there is also a rubber support body in which a side material composed of a coated rubber is provided so as to surround the outer side surface thereof (for example, refer to patent documents 1 to 3).

Further, since the coating rubber is required to have weather resistance (ozone resistance, etc.), an ethylene-propylene-diene terpolymer (hereinafter, abbreviated as "EPDM") having excellent weather resistance is recommended as a polymer component thereof.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2009-001603

Patent document 2: japanese patent No. 5712735

Patent document 3: japanese patent No. 5735886

Disclosure of Invention

Problems to be solved by the invention

However, when EPDM is used as the polymer component of the coating rubber, the following problems are likely to occur: the coated rubber is inferior in adhesion to a rubber support (main body), is crystallized at a low temperature and is easily hardened, and thus does not function in cold areas or the like (low Wen Xingbian difference), and is inferior in durability (tensile strength) at the time of large deformation.

Accordingly, it is necessary to solve the above-mentioned problems while maintaining the weatherability of EPDM.

The present invention has been made in view of such circumstances, and provides a rubber composition for a rubber support side wall, which exhibits high adhesion to a rubber support and can exhibit excellent low-temperature properties, durability and weather resistance, and a rubber support using the same.

Means for solving the problems

In view of the above, the inventors of the present invention studied the case where a diene rubber and a liquid rubber, which are mainly composed of natural rubber and isoprene rubber, are used in combination in addition to EPDM as a polymer component of a material for forming a side wall of a rubber support (rubber composition for a side wall of a rubber support). It was also found that, as the EPDM, an EPDM having a diene content and an ethylene content in a specific range was used, and as the liquid rubber, a liquid rubber having a molecular weight in a specific range was used, whereby it was possible to exhibit high adhesiveness to a rubber support (main body) and also to exhibit excellent low-temperature properties, durability and weather resistance.

By adopting the above-described constitution, it is possible to provide a rubber composition for a side wall of a rubber support, which exhibits high adhesiveness to the rubber support and is capable of exhibiting excellent low-temperature properties, durability and weather resistance, and a reason for using the rubber composition for a rubber support, which can be considered as follows. That is, in the present invention, it is considered that the diene content of EPDM is adjusted to be higher than usual in a specific range, and further, the diene rubber containing natural rubber or isoprene rubber as a main component is used together with the EPDM, so that the amount of diene that becomes the starting point of the adhesion reaction increases, and thus the adhesion can be improved. In the present invention, it is considered that the crystallinity is reduced by adjusting the ethylene content of EPDM to be smaller than the normal content within a specific range, and the low-temperature property can be improved. Further, it is considered that durability is normally lowered when the ethylene content of EPDM is lowered as described above, but in the present invention, the durability is suppressed from being lowered by the combination of the liquid rubber exhibiting a specific molecular weight to thereby enhance the durability. Further, it is considered that the liquid rubber has good fusion with EPDM, functions as a softener, and has a molecular weight higher than that of a commonly used softener (process oil), and thus contributes to durability as described above.

That is, the present invention provides the following [1] to [4].

[1] A rubber composition for a side wall of a rubber support, wherein the rubber composition for a side wall of a rubber support comprises the following (A) to (C) as a polymer component.

(A) Diene rubber containing at least one of natural rubber and isoprene rubber as a main component (but EPDM and liquid rubber are not included).

(B) EPDM having a diene content of 10 mass% or more and an ethylene content of 55 mass% or less.

(C) Liquid rubber with molecular weight of 1000-60000.

[2] The rubber composition for a side wall of a rubber support according to [1], wherein the ratio of (A) to (B) =50/50 to 90/10 in terms of mass ratio.

[3] The rubber composition for a side wall of a rubber support according to [1] or [2], wherein the proportion of (C) is5 to 30 parts by mass based on 100 parts by mass of the total amount of (A) and (B).

[4] A rubber support comprising a rubber and a hard plate laminated alternately, wherein the rubber support has a side surface material comprising a coated rubber comprising a crosslinked rubber of the rubber composition for a side wall of the rubber support described in any one of [1] to [3] so as to surround the outer side surface thereof.

Effects of the invention

As described above, the rubber composition for a side wall of a rubber support according to the present invention is used as a material for a side surface material formed so as to surround an outer surface of the rubber support, and thus exhibits high adhesion to the rubber support and can exhibit excellent low-temperature properties, durability, and weather resistance.

Drawings

Fig. 1 is a cross-sectional view showing an example of a vibration-proof support body.

Detailed Description

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

The rubber composition for a side wall of a rubber support of the present invention (hereinafter, abbreviated as "the present rubber composition") contains the following (a) to (C) as a polymer component. The rubber composition preferably contains only the following (a) to (C) as a polymer component, but may contain a small amount of other polymer components as required.

(C) Liquid rubber with molecular weight of 1000-60000.

The details of the respective components in the present rubber composition will be described below.

In the present specification, "X and/or Y (X, Y are arbitrary structures)" means at least one of X and Y, and means three of X alone, Y, X alone, and Y alone.

Diene rubber (A)

As the diene rubber (a), a diene rubber containing at least one (NR and/or IR) of a Natural Rubber (NR) and an Isoprene Rubber (IR) as a main component is used. In the present invention, "main component" generally means 55 mass% or more of the diene rubber (a), preferably 60 mass% or more of the diene rubber (a), more preferably 70 mass% or more of the diene rubber (a), and still more preferably 100 mass% of the diene rubber (a).

In addition to the main component, two or more types of Butadiene Rubber (BR), styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), chloroprene Rubber (CR), butyl rubber (IIR), and the like may be used alone or in combination as needed as the diene rubber (a).

In the present invention, the diene rubber (a) is not formed of EPDM (ethylene-propylene-diene terpolymer) or a liquid rubber.

In the present invention, the "liquid rubber" means a rubber exhibiting a viscosity of 1500pa·s or less at ordinary temperature (23 ℃). The viscosity can be measured, for example, using a type B viscometer.

Specific EPDM (B)

As the specific EPDM (B), EPDM having a diene content of 10 mass% or more is used from the viewpoint of obtaining desired adhesion or the like. From the same viewpoint, the diene content is preferably 12% by mass or more, more preferably 14% by mass or more. If the diene content is too small, the desired adhesion cannot be obtained, and peeling is caused. The upper limit of the diene content is usually 20% by mass, preferably 18% by mass, and more preferably 16% by mass.

In addition, as the specific EPDM (B), from the viewpoint of obtaining desired low temperature properties and the like, an EPDM having an ethylene content of 55 mass% or less is used. From the same viewpoint, the ethylene content is preferably less than 48 mass%, more preferably less than 45 mass%, and particularly preferably less than 43 mass%. If the ethylene content is too large, desired low-temperature properties and the like cannot be obtained. The lower limit of the ethylene content is usually 30% by mass, preferably 35% by mass, and more preferably 40% by mass.

The diene polymer used as the third component constituting the specific EPDM (B) is preferably a diene polymer 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-norbornene (ENB), 5-butylidene-2-norbornene, 2-methallyl-5-norbornene, 2-isopropenyl-5-norbornene, and the like can be mentioned. These may be used singly or in combination of two or more. Of these diene polymers (third component), dicyclopentadiene (DCP) and 5-ethylidene-2-norbornene (ENB) are preferable.

In the present rubber composition, it is preferable that the ratio of (a) to (B) =50/50 to 90/10 in terms of mass ratio is such that desired weather resistance, adhesiveness, and the like are obtained. From the same point of view, the ratio of (a)/(B) =60/40 to 80/20 is more preferable, and the ratio of (a)/(B) =65/35 to 70/30 is particularly preferable.

Specific liquid rubber (C)

As the specific liquid rubber (C), a liquid rubber having a molecular weight of 1000 to 60000 is used from the viewpoint of obtaining desired durability and the like. From the same viewpoint, the molecular weight of the liquid rubber is preferably 10000 to 55000, more preferably 25000 to 50000.

The molecular weight of the liquid rubber (C) is high, and is a value indicating a weight average molecular weight (Mw) (the same applies to examples described later). Here, the weight average molecular weight (Mw) is a weight average molecular weight obtained by converting a standard polystyrene molecular weight, and three columns connected in series are used in a high performance liquid chromatograph (manufactured by Waters corporation, "Waters 2695 (main body)" and "Waters 2414 (detector)"): shodex GPC KF-806L (exclusion limit molecular weight: 2×10) ⁷ Separation range: 100 to 2X 10 ⁷ Theoretical plate number: 10000 grade/root, filler material: styrene-divinylbenzene copolymer, filler particle size: 10 μm) was used for the measurement.

The specific liquid rubber (C) is a rubber which exhibits the molecular weight and a viscosity of 1500 Pa.s or less at ordinary temperature (23 ℃). 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), and the like are given. These may be used singly or in combination of two or more. Among them, liquid isoprene-butadiene block copolymers (liquid IR-BR) are preferable.

In the present rubber composition, the proportion of (C) is preferably 5 to 30 parts by mass based on 100 parts by mass of the total amount of (a) and (B) from the viewpoint of obtaining desired durability and the like. From the same viewpoint, in the present rubber composition, the proportion of (C) is preferably 10 to 25 parts by mass, more preferably 15 to 20 parts by mass, relative to 100 parts by mass of the total amount of (a) and (B).

The present rubber composition is usually blended with a filler such as carbon black or silica and a crosslinking agent together with a diene rubber (a) containing NR and/or IR as a main component, a specific EPDM (B) and a specific liquid rubber (C). The rubber composition may optionally contain a vulcanization accelerator, a vulcanization aid, an anti-aging agent, a softener, and the like.

In the present rubber composition, the specific liquid rubber (C) exhibits a function as a softener, and therefore, is preferably free of a softener.

Carbon black

As the carbon black, for example, various grades of carbon black such as SAF grade, ISAF grade, HAF grade, MAF grade, FEF grade, GPF grade, SRF grade, FT grade, and MT grade are used. These may be used singly or in combination of two or more. Among them, SAF grade carbon black is preferably used from the viewpoints of mechanical strength, elongation at break, and the like.

In the present rubber composition, the content of the carbon black is preferably 20 to 60 parts by mass based on 100 parts by mass of the total amount of the components (a) and (B) from the viewpoints of mechanical strength, elongation at break, and the like. From the same viewpoint, in the present rubber composition, the proportion of the carbon black is preferably 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 the components (a) and (B). In addition, if the content of the carbon black is too small, a tendency that desired reinforcing property or the like is not obtained can be observed, whereas if the content of the carbon black is too large, a tendency that scorch resistance is deteriorated and elongation is reduced can be observed.

Cross-linking Agents

Examples of the crosslinking agent include sulfur-based vulcanizing agents such as sulfur and sulfur chloride, and peroxide vulcanizing agents such as 2, 4-dichlorobenzoyl peroxide, benzoyl peroxide, 1-di-t-butylperoxy-3, 5-trimethylcyclohexane, 2, 5-dimethyl-2, 5-bis- (benzoyl peroxide) hexane, n-butyl-4, 4' -di-t-butylperoxyvalerate, dicumyl peroxide, t-butylperoxybenzoate, di-t-butyldiisopropylbenzene peroxide, t-butylcumyl peroxide, 2, 5-dimethyl-2, 5-di-t-butylperoxy hexane, di-t-butylperoxide, 2, 5-dimethyl-2, 5-di-t-butylperoxy hexyne-3, and 1, 3-bis (t-butylperoxyisopropyl) benzene. These may be used singly or in combination of two or more. Among them, sulfur and dicumyl peroxide are preferably used.

In the present rubber composition, the content of the crosslinking agent is preferably 0.5 to 3.0 parts by mass based on 100 parts by mass of the total amount of the components (a) and (B) from the viewpoint of obtaining desired durability and the like. From the same viewpoint, in the present rubber composition, the proportion of the crosslinking agent is preferably 0.75 to 2.5 parts by mass, more preferably 1.0 to 2.0 parts by mass, relative to 100 parts by mass of the total amount of the components (a) and (B). In addition, if the content of the crosslinking agent is too small, a tendency of lowering of tensile strength or the like can be observed, whereas if the content of the crosslinking agent is too large, a tendency of deterioration of scorch resistance and reduction of elongation can be observed.

Vulcanization accelerators

Examples of the vulcanization accelerator include thiazole-based vulcanization accelerators, sulfenamides, thiurams, aldomines, aldamines, guanidine-based vulcanization accelerators, thiourea-based vulcanization accelerators, and the like. These may be used singly or in combination of two or more. Among these, sulfenamide vulcanization accelerators are preferable in view of excellent crosslinking reactivity.

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

Examples of the thiazole-based vulcanization accelerator include dibenzothiazyl disulfide (MBTS), 2-Mercaptobenzothiazole (MBT), 2-mercaptobenzothiazole sodium salt (NaMBT), and 2-mercaptobenzothiazole zinc salt (ZnMBT). These may be used singly or in combination of two or more.

Examples of the sulfenamide vulcanization accelerator include N-oxydiethylene-2-benzothiazole sulfenamide (NOBS), N-cyclohexyl-2-benzothiazole sulfenamide (CBS), N-tert-butyl-2-benzothiazole sulfenamide (BBS), and N, N' -dicyclohexyl-2-benzothiazole sulfenamide. These may be used singly or in combination of two or more.

Examples of the thiuram-based vulcanization accelerator include tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide (TETD), tetrabutylthiuram disulfide (TBTD), tetra (2-ethylhexyl) thiuram disulfide (TOT), and tetrabenzylthiuram disulfide (TBzTD). These may be used singly or in combination of two or more.

Vulcanization aids

Examples of the vulcanization aid include stearic acid, magnesium oxide, and zinc oxide. These may be used singly or in combination of two or more.

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

Anti-aging agent

Examples of the aging inhibitors include urethane aging inhibitors, phenylenediamine aging inhibitors, phenol aging inhibitors, diphenylamine aging inhibitors, quinoline aging inhibitors, imidazole aging inhibitors, and waxes. These may be used singly or in combination of two or more.

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

Softener (A)

Examples of the softener (processing oil) include naphthenic oil, paraffinic oil, aromatic oil, and the like. These may be used singly or in combination of two or more.

In the present rubber composition, the content of the softener is preferably in the range of 0 to 20 parts by mass, more preferably 0 to 10 parts by mass, based on 100 parts by mass of the total amount of (a) and (B).

Further, as described above, in the present rubber composition, since the specific liquid rubber (C) exhibits a function as a softener, desired performance can be exhibited even if the softener is not contained.

The present rubber composition can be produced by mixing the above-mentioned components by using a kneader, a Banbury mixer, a roll or the like.

The present rubber composition is a rubber composition used specifically for forming a side wall of a rubber support having vibration-proof properties. The rubber composition is preferably used as a material for the side wall of a large support such as a support for a bridge or a support for a building.

As shown in fig. 1, for example, a vibration-proof support for a bridge or a building is formed by alternately laminating and integrating hard plates 1 and rubber layers 2, and a side material 5 made of a coated rubber is provided so as to surround the outer side surface thereof. The rubber support (hereinafter, simply referred to as "present rubber support") as one embodiment of the present invention is a rubber support in which the side material 5 is composed of a crosslinked body of the present rubber composition. The illustrated upper mounting plate 3 and lower mounting plate 4 are metal mounting plates, and are bonded and fixed to the upper and lower portions of the laminate between the hard plate 1 and the rubber layer 2. In the shock-proof support body, the lower mounting plate 4 is fixed to a lower structure such as a bridge column, and the upper mounting plate 3 is fixed to an upper structure such as a bridge girder.

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

The rubber composition as the material of the rubber layer 2 is a rubber composition containing a diene rubber such as NR or IR as a polymer component and a vulcanizing agent. In addition, carbon black, a softener, an anti-aging agent, a processing aid, a vulcanization accelerator, a white filler, a reactive polymer, a foaming agent, and the like may be appropriately blended into the rubber composition as needed.

The rubber composition can be produced by kneading the above-mentioned materials by using a kneader, a Banbury mixer, an open roll, a twin-screw mixer, or other such kneader.

Here, the present rubber support (see fig. 1) is manufactured, for example, as follows. That is, first, a rubber composition as a material for the rubber layer 2 is produced as described above. Next, a plurality of hard plates 1 of a predetermined size are prepared, and further, an upper mounting plate 3 and a lower mounting plate 4 are also prepared.

Then, a rubber composition as a material for the rubber layer 2 is formed into a sheet shape on the lower mounting plate 4, and unvulcanized rubber sheets bored in a predetermined size are alternately overlapped with the hard plate 1, and finally, the upper mounting plate 3 is overlapped, thereby manufacturing a laminate (rubber support). In addition, an adhesive may be applied in advance to the laminated surface of the hard sheet 1 and the like.

Next, the present rubber composition produced as described above is formed into a sheet shape to produce an unvulcanized rubber sheet. The unvulcanized rubber sheet is a material which is half-crosslinked to an extent of incomplete crosslinking (to an extent that vulcanized adhesiveness can be obtained), and the molding conditions thereof vary depending on the thickness, but is usually a material which is half-crosslinked by heating at 130 to 180 ℃ for 1 to 30 minutes. Then, the unvulcanized rubber sheet is coated so as to surround the outer side surface of the laminate (rubber support), and then the material is placed in a predetermined mold, and the unvulcanized rubber sheet is heated at 130 to 180 ℃ for 1 to 24 hours to crosslink, vulcanize and bond the unvulcanized rubber sheet to the rubber support, whereby a rubber support (rubber support) having a side surface material 5 composed of the present rubber composition can be produced.

The laminate (rubber support) can also be produced by the following method: the hard plate 1, the upper mounting plate 3, and the lower mounting plate 4 are placed in a molding die so as to be arranged in a predetermined configuration, a rubber composition as a material for the rubber layer 2 is injected into a space in the molding die by injection molding or the like, and the mold is released after vulcanization by heating.

The rubber support may be produced as follows. That is, a rubber composition as a material for the rubber layer 2 is formed into a rubber sheet (rubber layer 2) having a predetermined thickness by extrusion molding or the like, and then the rubber sheet and the predetermined hard plate 1 are alternately laminated and bonded with an appropriate adhesive to produce a rubber fitted body, and further, if necessary, the upper mounting plate 3 and the lower mounting plate 4 are bonded to the upper and lower surfaces thereof and integrated. The side surface material 5 is formed on the outer side surface of the rubber support obtained in this manner by the method described above, whereby the rubber support can be produced.

In addition, the side material 5 may be formed by: after the rubber support is set in a predetermined mold, the present rubber composition is injected between the outer peripheral surface of the rubber support and the inner peripheral surface of the mold by injection molding or the like, and the present rubber composition is crosslinked.

The heating conditions at the time of the crosslinking are in accordance with the aforementioned production method. However, the crosslinking may be performed by direct heating without the need for a half-crosslinking step as in the previous production method.

The size of the rubber support obtained in this way is, for example, about 20 to 200cm in outer diameter, and about 10 to 80cm in total thickness. Further, the thickness of each layer constituting the present rubber support may be within a range that can sufficiently achieve the function as the purpose of each layer, for example, the thickness of the hard plate 1 is about 0.1 to 2cm for one layer, the thickness of the rubber layer 2 is about 0.5 to 7cm for one layer, and the thickness of the side material 5 is about 0.5 to 10 cm. Further, the number of layers of the hard plate 1 and the rubber layer 2 in the present rubber support may be appropriately set according to the use of the vibration-insulating laminate.

The outer shape of the rubber support may be appropriately set to a cylindrical shape, an elliptic cylindrical shape, a quadrangular prism shape, or the like, depending on the application.

Examples

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

First, the materials (polymer component and softener) shown below were prepared before examples and comparative examples.

〔NR〕

Natural rubber

〔IR〕

Japanese rayleigh (ZEON) company, product name: nipol IR2200

〔EPDM(i)〕

Manufactured by Mitsui chemical company, product name: triplex position EPT 9090M (ethylene content: 41% by mass, diene content: 14% by mass)

〔EPDM(ii)〕

JSR corporation, product name: EP331 (ethylene content: 47% by mass, diene content: 11.3% by mass)

〔EPDM(iii)〕

Manufactured by Sumitomo chemical Co., ltd., product name: esprene505 (ethylene content: 50% by mass, diene content: 10% by mass)

〔EPDM(iv)〕

Manufactured by Mitsui chemical company, product name: triple well EPT 8030M (ethylene content: 47% by mass, diene content: 9.5% by mass)

〔EPDM(v)〕

Lanxess company, product name: keltan K3960Q (ethylene content: 56 mass%, diene content: 11.4 mass%)

[ liquid rubber (i) ]

Colali (KURARAY) company, product name: LIR-30 (weight average molecular weight: 28000)

[ liquid rubber (ii) ]

Colali (KURARAY) company, product name: LIR-50 (weight average molecular weight: 54000)

[ liquid rubber (iii) ]

EVONIK corporation, product name: POLYVEST110 (molecular weight: 1100)

[ softener ]

Manufactured by sun oil company, japan, product name: sunpar110

Examples 1 to 10 and comparative examples 1 to 5

After blending the above-mentioned polymer components and softeners in the proportions shown in tables 1 and 2, 2 parts by mass of stearic acid (manufactured by daily oil Co., ltd., product name: BEADS STEARIC ACID SAKURA), 5 parts by mass of zinc oxide (manufactured by Gekko chemical industries Co., ltd., product name: two kinds of zinc oxide), 3 parts by mass of an amine-type anti-aging agent (manufactured by Seiko chemical Co., ltd., product name: ozonone 6C), 4 parts by mass of wax (manufactured by Dain New chemical Co., ltd., product name: SUNNOC), 35 parts by mass of SAF-grade carbon black (manufactured by Tohai carbon Co., ltd., product name: SEAST 9M), 1 part by mass of a sulfenamide-type vulcanization accelerator (manufactured by Dain New chemical Co., ltd., product name: NOCCELER-CZ-G), and 1 part by mass of sulfur (manufactured by Gekko chemical Co., ltd., product name: jin Huayin sulfur) were added, and a Banbury mixer and an open roll was used to prepare a rubber composition (a rubber composition for a side wall support micro powder). Specifically, the components other than the vulcanizing agent and the vulcanization accelerator were kneaded for 5 minutes using a banbury mixer, and discharged when the temperature reached 150 ℃, to obtain a master batch, and then the vulcanizing agent and the vulcanization accelerator were blended in the same proportions as shown in the table in the master batch, and these were kneaded by an open roll to prepare the rubber composition.

The rubber compositions of examples and comparative examples obtained in this manner were used to evaluate the respective characteristics according to the following criteria. The results are shown in tables 1 and 2.

< tensile Strength >

Using each of the obtained rubber compositions, press molding (vulcanization) was performed at 150 ℃. Then, a JIS No. 5 dumbbell was punched out from the rubber sheet, and the tensile strength in an atmosphere at 25℃was measured in accordance with JIS K6251.

The tensile strength was evaluated as "good" (15 MPa) to less than 20MPa, as "good" (very good) ", as" delta "(good)", as 10MPa to less than 15MPa, and as "× (pore)", as less than 10 MPa.

< Low temperature Property >

Using each of the obtained rubber compositions, a test piece for a cylindrical shearing method with a die, which was defined in JIS K6394 "dynamic characteristics test method for vulcanized rubber and thermoplastic rubber", was produced under vulcanization conditions of 150℃for 30 minutes. Thereafter, using each of the obtained test pieces, "dynamic characteristics test of a large-scale test apparatus" specified in JIS K6394 (1998), at a test temperature: -30 ℃, 20 ℃, test vibration frequency: deformation amplitude (shear) at 0.5 Hz: at 250%, 11 load/deflection curves were measured continuously.

Then, from the obtained load/deflection curves of total 10 times from the 2 nd to 11 th times, the equivalent rigidity at each measured temperature was obtained: keq (-30 ℃), keq (20 ℃). Using the obtained equivalent rigidity, G (temperature dependence) was calculated from the following equation. Then, the evaluation of G less than 1.5 was "good", the evaluation of G1.5 or more and less than 1.6 was "Δ (good)", and the evaluation of G1.6 or more was "× (pool)".

G (temperature dependence) = Kep (-30 ℃ C.)/Kep (20 ℃ C.)

< adhesion >

Using each of the obtained rubber compositions, vulcanization (vulcanization adhesion) was performed by heating at 150℃for 30 minutes on an iron plate. Regarding the adhesiveness between the iron plate and the rubber in the test piece obtained in this manner, "5. 90 degree peel test of the metal plate and the rubber" in "adhesion test method of vulcanized rubber" according to JIS K6256, the rubber adhered to the iron plate was peeled in the direction of 90 degrees, and the state of the peeled portion was visually observed. Then, the breakage ratio of the rubber portion was evaluated as "o (good)", and the portion having the interface separation between the rubber portion and the iron plate was evaluated as "x (pool)".

< ozone resistance >

Using each of the obtained rubber compositions, press molding (vulcanization) was performed at 150 ℃. Test pieces were produced by punching JIS No. 1 dumbbell from the rubber sheet. Then, the test piece was put into an ozone tank having an ozone concentration of 200.+ -.20 pphm and a temperature of 40℃in a state of imparting a tensile strain of 80.+ -. 2% in accordance with JIS K6259. After 672 hours from the time of the loading, the test piece was visually inspected for the presence or absence of cracks, and the test piece was evaluated as "good" and "x (hole)".

Table 1 (parts by mass)

Table 2 (parts by mass)

From the results of table 1, it is understood that the rubber composition of examples shows high adhesiveness by crosslinking and can exhibit excellent properties of low temperature properties, tensile strength (durability) and ozone resistance (weatherability), and is therefore excellent as a rubber composition for a side wall of a rubber support.

Therefore, it was determined that the rubber composition of the example was excellent as a material for a side material of a vibration-proof support for bridge use and building use as shown in fig. 1.

In contrast, according to the results of table 2, the rubber composition of comparative example 1 was inferior to the ozone resistance (weatherability) of example in that the polymer component thereof was a natural rubber alone. The rubber composition of comparative example 2 has a lower diene content than EPDM, and thus has a lower adhesiveness than that of example. Since the rubber composition of comparative example 3 has a large ethylene content in EPDM, the low-temperature property of the rubber composition is inferior to that of example. The rubber composition of comparative example 4 uses a softener having a lower molecular weight (molecular weight less than 1000) than that of the liquid rubber, and thus has a lower tensile strength than that of the example. The rubber composition of comparative example 5 does not contain a liquid rubber and has a large EPDM ratio, and therefore has lower tensile strength, low-temperature properties and adhesiveness than those of examples.

In the above examples, specific embodiments are shown with respect to the present invention, but the above examples are merely examples and are not to be construed as limiting. Various modifications, which are apparent to those skilled in the art, are intended to fall within the scope of the invention.

Industrial applicability

The rubber composition for a side wall of a rubber support of the present invention is a rubber composition used specifically for forming a side wall of a rubber support having vibration-proof properties and vibration-proof properties. The rubber composition can be preferably used as a material for the side wall of a large support such as a support for a bridge or a support for a building, but can be used for vibration damping materials for automobiles, vibration dampers for general household electrical appliances such as washing machines, and the like.

Description of the reference numerals

1: a hard plate;

2: a rubber layer;

5: side material.

Claims

1. A rubber composition for a side wall of a rubber support, wherein the rubber composition for a side wall of a rubber support comprises the following (A) to (C) as polymer components:

(A) Diene rubbers containing at least one of a natural rubber and an isoprene rubber as a main component, but do not contain an ethylene-propylene-diene terpolymer and a liquid rubber;

(B) An ethylene-propylene-diene terpolymer having a diene content of 10 mass% or more and an ethylene content of 55 mass% or less;

(C) Liquid rubber with molecular weight of 1000-60000.

2. The rubber composition for a side wall of a rubber support according to claim 1, wherein the ratio of (a) to (B) =50/50 to 90/10 in terms of mass ratio.

3. The rubber composition for a side wall of a rubber support according to claim 1 or 2, wherein the proportion of (C) is5 to 30 parts by mass based on 100 parts by mass of the total amount of (A) and (B).

4. A rubber support body formed by alternately laminating rubber and hard plates, wherein,

the rubber support body has a side material composed of a coated rubber so as to surround the outer side surface thereof,

the coated rubber is composed of the crosslinked rubber of the rubber composition for a side wall of a rubber support according to any one of claims 1 to 3.