TWI656023B - Rubber support - Google Patents

Abstract

The present invention provides a rubber support in which the coating rubber composition which is a raw material of the coating layer is less likely to be coked, and the coating layer including the coating rubber composition is excellent in both of the tensile properties and the vulcanization property, even if the deformation amount is Big also follows well without breaking or stripping. The coating layer is formed of a coating rubber composition containing a rubber component containing a chloroprene rubber in a ratio of 30 parts by mass to 95 parts by mass, and a mass of 0.1 part by mass based on 100 parts by mass of the rubber component. 4 parts by mass of 4,4'-dithiomorpholine, 2-(morpholinyldithio)benzothiazole, or dipentamethylenethiuram tetrasulfide as a crosslinking agent.

Description

Rubber support

The present invention relates to a rubber support which is incorporated as part of various structures such as a joint portion of a bridge structure and a lower structure, or a foundation of a building, and is responsible for load transfer function and displacement of the structures. Follow function and vibration reduction function during earthquake.

In recent years, the earthquake-resistant structure in which rubber joints are incorporated in the joint portion of the bridge or the foundation of the building has been popularized. The rubber support constituting the earthquake-resistant structure includes a laminate or the like, and the laminate is formed by, for example, alternately laminating a soft layer containing a rubber composition and a hard layer including a steel plate and having rigidity. In addition, the laminated body is formed by vulcanizing and vulcanizing each other in a state in which the rubber composition and the hard layer are alternately laminated.

Usually, the soft layer is formed of a rubber composition containing a diene rubber excellent in vibration damping performance as a rubber component. However, the soft layer containing the rubber composition containing the diene rubber has a problem that the ozone resistance is insufficient, particularly when the structure is subjected to a large load and is often continuously exposed to the air in a state of compression deformation. Ozone degradation is prone to occur.

Therefore, the coating layer excellent in ozone resistance may be coated on the outer periphery of the laminated body constituting the rubber support, and the soft layer may not be in direct contact with the air. In general, the coating layer contains, for example, a diene rubber for ensuring vulcanization adhesion to a soft layer and a non-diene rubber excellent in ozone resistance as a rubber component and sulfur as a crosslinking agent (vulcanizing agent). The coating rubber composition is formed, and the soft layer and the hard layer are vulcanized and subsequently vulcanized with the outer periphery (for example, see Patent Document 1).

It is required that the coating rubber composition which is a raw material of the coating layer is scorched without causing the crosslinking speed to be too fast. Further, the coating layer is required to satisfactorily follow a large deformation due to an earthquake without being broken or peeling off from the laminate. Therefore, it is also required to have excellent tensile properties or vulcanization properties. In many cases, the rubber support is large depending on the size of the structure, and the rubber support of a large structure such as a bridge has a large amount of deformation at the time of an earthquake. Therefore, the tensile property or the vulcanization adhesion is particularly required to be excellent.

However, the current situation is that the previous coating layer containing the coating rubber composition cannot adequately cope with these requirements. [Prior Art Document] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2013-35943

[Problems to be solved by the invention]

An object of the present invention is to provide a rubber support in which a coating rubber composition which is a raw material of a coating layer is less likely to be coked, and the coating layer containing the coating rubber composition is excellent in both of tensile properties and vulcanization properties. Even if the amount of deformation is large, it will follow well without cracking or peeling. [Means for solving the problem]

The present invention is a rubber support comprising: a laminate body in which a soft layer and a rigid hard layer are alternately laminated; and a coating layer covering the outer periphery of the laminate; and the coating layer includes a coating In the rubber composition, the rubber component is contained in an amount of 0.1 part by mass or more and 4 parts by mass or less based on 100 parts by mass of the rubber component, and is selected from 4,4'-dithiomorpholine, 2-( At least one crosslinking agent in the group consisting of morpholinyldithio)benzothiazole and dipentamethylenethiuram tetrasulfide, the rubber component being in the chloroprene rubber and at least one other rubber The chloroprene rubber is contained in a ratio of 30 parts by mass or more and 95 parts by mass or less in 100 parts by mass of the total amount. [Effects of the Invention]

According to the present invention, it is possible to provide a rubber support in which the coating rubber composition which is a raw material of the coating layer is less likely to be coked, and the coating layer containing the coating rubber composition is excellent in both of the tensile properties and the vulcanization adhesion property. Even if the amount of deformation is large, it will follow well without cracking or peeling.

According to the present invention, a chloroprene rubber (CR) in a diene rubber is formulated as a rubber component in the predetermined ratio, and the three crosslinking agents are formulated in the predetermined ratio. At least one type of sulfur is used as a crosslinking agent instead of the former sulfur, and it is also clear from the results of the examples and comparative examples described later that a coating rubber composition which does not cause a too high crosslinking speed to cause scorch can be formed.

Further, according to the present invention, it is also clear from the results of the above-described examples and comparative examples that the coating rubber composition can be used, and it is possible to form both of the properties including the tensile properties and the vulcanization adhesion, even if the deformation amount is obtained. The rubber support of the coating layer that follows well without breaking or peeling. <<Coated Rubber Composition>> <Rubber Component> (CR) For the CR in the rubber component, any of various chloroprene rubbers containing at least chloroprene as a repeating unit can be used.

In other words, examples of the CR include, for example, a thiol-modified chloroprene rubber and a xanthogen-modified chloroprene which are synthesized by emulsion polymerization of chloroprene and classified according to the type of the molecular weight modifier used at this time. a homopolymer of chloroprene such as diene rubber or sulfur-modified chloroprene rubber; or chloroprene and, for example, 2,3-dichloro-1,3-butadiene, 1-chloro-1, One or two or more copolymers of 3-butadiene, styrene, acrylonitrile, methacrylonitrile, isoprene, butadiene, acrylic acid, acrylate, methacrylic acid, and methacrylate Wait.

Further, CR may be any one of an oil-filled CR in which flexibility is added by adding extender oil, and an oil-free CR in which no filler oil is added. One or two or more of these CRs can be used. However, when it is considered that the coating layer is excellently formed by the specific crosslinking agent, the effect of forming the coating layer excellent in both of the tensile properties and the vulcanization adhesion property is considered. One or two or more kinds of homopolymers of chloroprene such as thiol modified chloroprene rubber, xanthan modified chloroprene rubber, and sulfur modified chloroprene rubber.

(Other rubber) The other at least one type of rubber which forms a coating layer together with CR is preferably a non-diene rubber which has a function of improving the ozone resistance of the coating layer as described above. The non-diene rubber is, for example, at least one selected from the group consisting of ethylene-α-olefin copolymer rubber, ethylene-α-olefin-non-conjugated polyene copolymer rubber, and butyl rubber.

Further, the ethylene-α-olefin copolymerized rubber is preferably an ethylene propylene rubber (EPM) obtained by copolymerizing ethylene and propylene in an arbitrary ratio. Since EPM does not have a double bond in the main chain, the effect of improving the ozone resistance of the coating layer is particularly excellent. Further, the ethylene-α-olefin-non-conjugated polyene copolymerized rubber is preferably an ethylene propylene diene rubber having a double bond introduced into the main chain by adding a small amount of a diene to ethylene and propylene (Ethylene Propylene). Diene Monomer, EPDM). EPDM has the advantage of having a slightly lower but moderate ozone resistance compared to EPM, and may be crosslinked with CR by the specific crosslinking agent without additional peroxide crosslinking agent or the like.

Further, a butyl rubber (Isobutylene Isoprene Rubber, IIR) obtained by copolymerizing isobutylene with a small amount of isoprene or a halogen obtained by introducing a halogen such as chlorine or bromine into the butyl rubber can be used as the butyl rubber. IIR and so on. The IIR or halogenated IIR has the advantage of having moderate ozone resistance, and may be crosslinked with CR by the specific crosslinking agent without additional peroxide crosslinking agent or the like.

In addition, the other rubber may be used in combination with other diene rubbers in such a range as not to impede the following effects: the tensile properties and the vulcanization properties which are obtained by selectively using CR as described above are excellent. The effect of the coating layer or the effect of improving the ozone resistance of the coating layer obtained by using a non-diene rubber in combination. Examples of the other diene rubber include natural rubber, isoprene rubber (IR), butadiene rubber (BR), and styrene butadiene rubber (SBR). One or two or more.

However, in consideration of simplifying the configuration of the coating rubber composition and further improving the above-described effects, it is preferable that the rubber component does not mix other diene rubbers other than CR, and only CR and at least one non-diene rubber are used in combination. Further, each of the various rubbers may be an oil-extended rubber in which a filler oil is added to adjust flexibility, and an oil-free rubber in which no filler oil is added, and any of them may be used.

(Preparation ratio) The blending ratio of the CR is required to be 30 parts by mass or more and 95 parts by mass or less based on 100 parts by mass of the total amount of the rubber component. When the blending ratio of CR is less than the above range, the tensile properties of the coating layer are lowered or the vulcanization adhesion to the soft layer is lowered, and as a result, the coating layer is easily broken or peeled off when the rubber support deformation is large.

On the other hand, when the blending ratio of CR exceeds the above range, when combined with the specific crosslinking agent, the crosslinking speed becomes too fast, and the coated rubber composition is liable to be scorched. . Further, when the other rubber is the non-diene rubber, there is no possibility of ensuring good ozone resistance based on the non-diene rubber. On the other hand, by setting the blending ratio of CR to the above range, coking does not occur even when combined with the specific crosslinking agent, and a coating having greatly improved tensile properties and vulcanization properties can be formed. Floor.

In addition, when the effect is further improved, the blending ratio of CR is preferably 60 parts by mass or more, particularly 70 parts by mass or more, based on 100 parts by mass of the total amount of the rubber component in the above range. Of course, the ratio of other rubbers is the remaining amount of CR. The blending ratio of the other rubber may be set so that the total amount of CR of the predetermined blending ratio plus the other rubber is 100 parts by mass.

In addition, when any of the rubbers is an oil-filled rubber, the blending ratio is set such that the ratio of the rubber itself which is a solid component other than the filler oil is within the above range. <Crosslinking Agent> The crosslinking agent is selected from the group consisting of 4,4′-dithiomorpholine (R), 2-(morpholinyldithio)benzothiazole (MDB), and tetrasulfide. At least one of the groups consisting of bis-pentamethylene thiuram (TRA) replaces the previous sulfur.

The blending ratio of the crosslinking agent must be 0.1 parts by mass or more and 4 parts by mass or less based on 100 parts by mass of the total amount of the rubber component. When the blending ratio of the crosslinking agent is less than the above range, the rubber component cannot be sufficiently crosslinked. Therefore, as described above, the coating layer in which both of the tensile properties and the vulcanization property are greatly improved cannot be formed. On the other hand, when the compounding ratio of the crosslinking agent exceeds the above range, the crosslinking speed becomes too fast, and the coated rubber composition is likely to be scorched.

On the other hand, by setting the blending ratio of the crosslinking agent to the above range, it is possible to form a coating layer in which both of the tensile properties and the vulcanization property are greatly improved without causing coking. In addition, when the effect is further improved, the blending ratio of the crosslinking agent is preferably 2 parts by mass or more, particularly preferably 3 parts by mass or more, based on 100 parts by mass of the total amount of the rubber component in the above range.

<Other crosslinking component> Various accelerators, promoters, and the like may be blended in the coating rubber composition together with the crosslinking agent. Among them, examples of the accelerator include 2-mercaptobenzothiazole (M), di(2-benzothiazole) disulfide (DM), tetramethylthiuram monosulfide (TS), and tetramethylsulfide disulfide. One or more of Lamb (TT), tetraethylthiuram disulfide (TET), and the like.

In addition, examples of the auxiliary agent include metal oxides such as magnesium oxide and zinc oxide (zinc oxide), and one or two or more kinds of fatty acids such as stearic acid, oleic acid, and cottonseed fatty acid. Among them, magnesium oxide also functions as an anti-coking agent and an acid neutralizing agent which neutralizes an acid generated when CR is crosslinked. In addition, fatty acids such as stearic acid also function as lubricants and processing aids.

Further, as described above, an ethylene-α-olefin-non-conjugated polyene copolymer rubber such as EPDM, or a butyl rubber such as a butyl rubber or a halogenated butyl rubber can be used together with a diene rubber such as CR. The crosslinking agent crosslinks, but since the ethylene-α-olefin copolymer rubber such as EPM cannot be crosslinked, the peroxide crosslinking agent is further used in combination as another crosslinking agent. Examples of the peroxide crosslinking agent include dibenzoyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, α,α. '-Di(t-butylperoxy)diisopropylbenzene, tert-butylperoxy peroxy, di-hexyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2 , 5-bis(t-butylperoxy)hexyne-3, 1,1-di(trihexylperoxy)cyclohexane, 1,1-di(t-butylperoxy)cyclohexane, 4,4-di(t-butylperoxy)-n-butyl valerate, 2,5-dimethyl-2,5-bis(benzhydrylperoxy)hexane, benzoic acid benzoic acid One or two or more kinds of esters, tert-butyl peroxybenzoate, and the like.

The blending ratio of the various cross-linking components can be appropriately set depending on the type or combination of the rubber component or the cross-linking component. <Other components> Various additives such as a filler and a plasticizer may be further added to the coating rubber composition as needed.

Among them, examples of the filler include carbon black, silica, and the like, and carbon black is particularly preferable. As the carbon black, one type or two or more types of carbon black which can function as a filler among various carbon blacks classified according to the production method and the like can be used.

The blending ratio of the carbon black is preferably 30 parts by mass or more, and preferably 50 parts by mass or less, based on 100 parts by mass of the total amount of the rubber component. Further, as the cerium oxide, any of wet-process cerium oxide and dry-process cerium oxide classified according to the production method thereof can be used. In the case where cerium oxide is used as a filler, it is preferred to use a decane compound in combination in order to increase the interaction with the rubber component.

The plasticizer is a component for imparting flexibility to a coating rubber composition in which a rubber component which is not oil-extended, in particular, is used, and a coating layer formed by crosslinking the coating rubber layer is provided, for example, a plasticizer. One or two or more kinds of dioctyl sebacate (DOS), dioctyl phthalate (DOP), and bis(2-ethylhexyl) sebacate (DOZ) may be mentioned.

The blending ratio of the plasticizer can be arbitrarily set depending on the type or blending ratio of the rubber component to be combined, the workability required for the coated rubber composition, the flexibility required for the coating layer, and the like, but is preferably set. 100 parts by mass based on the total amount of the rubber component is 1 part by mass or more, and preferably 10 parts by mass or less. The coating rubber composition may further be formulated with an anti-aging agent, an oil, a liquid rubber, and various other additives in an arbitrary ratio as needed.

<<Rubber Support>> The rubber support of the present invention can be configured in the same manner as the above except that the coating layer containing the coating rubber composition is provided. In other words, the rubber support includes a laminated body obtained by alternately laminating a soft layer having rubber elasticity or a soft layer containing a high damping rubber and a rigid layer having rigidity.

The laminated body is formed by vulcanizing and vulcanizing each other in a state in which a rubber composition which is a raw material of the soft layer and a hard layer are alternately laminated. Further, the coating layer is formed by vulcanization of the soft layer and the hard layer and subsequent vulcanization of the outer layer. In this case, the coating layer excellent in vulcanization property with the soft layer can be formed by the structure of the coating rubber composition described above.

The soft layer is preferably formed of a rubber composition containing a diene rubber excellent in vibration damping performance as a rubber component as described above. In particular, if it is considered to improve the vibration damping performance as much as possible, and also to improve the vulcanization adhesion to the coating layer as much as possible, the soft layer is preferably composed of a group selected from the group consisting of natural rubber, CR, SBR, and BR. At least one of the group is formed as a rubber composition of a rubber component.

The rubber composition is prepared by blending a rubber component such as a sulfur-crosslinking crosslinking agent or a filler such as carbon black to crosslink the rubber component. Further, the rubber composition may further be formulated with an anti-aging agent, an oil, a liquid rubber, and various other additives in an arbitrary ratio as needed. In the production of the rubber support of the present invention having the above-described respective portions, first, a sheet of a raw material which is a soft layer formed by molding the rubber composition into a predetermined thickness and a hard layer such as a steel sheet are alternately laminated to form a laminate. body.

Then, the sheet obtained by molding the coated rubber composition into a sheet having a predetermined thickness is wound around the outer circumference of the laminate without causing a gap, and when the whole is heated in this state, a laminate is formed. The sheet of the body is crosslinked to form a soft layer, and the sheet of the rubber composition is crosslinked to form a coating layer, and the soft layer and the hard layer, and the soft layer and the coating layer are vulcanized to each other to complete rubber support. [Examples]

<Example 1> A rubber component in each component shown in the following Table 1 was kneaded, and a component other than the crosslinking agent was first added and kneaded, and finally, a crosslinking agent was added and kneaded to prepare a coating rubber composition.

[Table 1]

The components in Table 1 are as follows. CR1: thiol modified CR, raw rubber viscosity (Mooney viscosity) ML _{1 + 4} (100 ° C) = 80, not oil-filled, electrical chemical industry company made EPDM: ethylene content 50%, diene content 9.5 %, unfilled, Esprene (registered trademark) 505A crosslinker manufactured by Sumitomo Chemical Co., Ltd. R: 4,4'-dithiomorpholine, Vulnoc (registered trademark) manufactured by Ouchi Shinko Chemical Co., Ltd. R Stearic acid: Stearic acid 50S anti-aging agent manufactured by New Japan Physical and Chemical Co., Ltd.: N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine, Ou Nei emerging chemistry Nocrac (registered trademark) 6C carbon black manufactured by Industrial Co., Ltd.: FEF, Toast SO plasticizer manufactured by Tokai Carbon Co., Ltd.: DOS, Daeba Chemical Industry Co., Ltd. Magnesium oxide: Concord Kyowamag (registered trademark) 150 manufactured by Industrial Co., Ltd. Zinc Hua: Two kinds of promoters of zinc oxide manufactured by 堺Chemical Industry Co., Ltd. TT: tetramethyl thiuram disulfide, manufactured by Ouchi New Chemical Industry Co., Ltd. Nocceler (registered TT CR1 scale compounding ratio) is 80 parts by mass of the total amount of 100 parts by mass of the rubber ingredient, the formulation of the crosslinking agent R is the total amount of the rubber component relative to 100 parts by mass of 1 part by mass.

<Example 2> A coated rubber composition was prepared in the same manner as in Example 1 except that the CR1 in Table 1 was 30 parts by mass and the EPDM was 70 parts by mass. The blending ratio of CR1 is 30 parts by mass in 100 parts by mass of the total amount of the rubber component, and the blending ratio of the crosslinking agent R is 1 part by mass based on 100 parts by mass of the total amount of the rubber component.

<Example 3> A coated rubber composition was prepared in the same manner as in Example 1 except that the CR1 in Table 1 was 95 parts by mass and the EPDM was 5 parts by mass. The blending ratio of CR1 is 95 parts by mass in 100 parts by mass of the total amount of the rubber component, and the blending ratio of the crosslinking agent R is 1 part by mass based on 100 parts by mass of the total amount of the rubber component.

<Example 4> A coated rubber composition was prepared in the same manner as in Example 1 except that the crosslinking agent R in Table 1 was changed to 0.1 part by mass. The blending ratio of CR1 is 80 parts by mass in 100 parts by mass of the total amount of the rubber component, and the blending ratio of the crosslinking agent R is 0.1 part by mass based on 100 parts by mass of the total amount of the rubber component.

<Example 5> A coated rubber composition was prepared in the same manner as in Example 1 except that the crosslinking agent R in Table 1 was changed to 4 parts by mass. The blending ratio of CR1 is 80 parts by mass in 100 parts by mass of the total amount of the rubber component, and the blending ratio of the crosslinking agent R is 4 parts by mass based on 100 parts by mass of the total amount of the rubber component.

<Example 6> An equivalent amount of bromobutyl rubber was prepared [EXXON (registered trademark) BUROMOBUTYL (Exxon Bromobutyl 2255), Br-IIR, which is not oil-filled, manufactured by ExxonMobil Chemical Co., Ltd.] A coated rubber composition was prepared in the same manner as in Example 1 except for the EPDM in the middle. The blending ratio of CR1 is 80 parts by mass in 100 parts by mass of the total amount of the rubber component, and the blending ratio of the crosslinking agent R is 1 part by mass based on 100 parts by mass of the total amount of the rubber component.

<Example 7> An equivalent amount of 2-(morpholinyldithio)benzothiazole [Nocceler MDB manufactured by Ouchi Shinko Chemical Co., Ltd., crosslinking agent MDB] was prepared in place of the crosslinking agent R in Table 1. A coating rubber composition was prepared in the same manner as in Example 1 except the above. The blending ratio of CR1 is 80 parts by mass in 100 parts by mass of the total amount of the rubber component, and the blending ratio of the crosslinking agent MDB is 1 part by mass based on 100 parts by mass of the total amount of the rubber component.

<Example 8> An equivalent amount of tetrakisuccine thiuram tetrasulfide [Sanceler (registered trademark) TRA manufactured by Sanshin Chemical Industry Co., Ltd., crosslinking agent TRA] was prepared in place of the crosslinking agent R in Table 1. A coating rubber composition was prepared in the same manner as in Example 1 except the above. The blending ratio of CR1 is 80 parts by mass in 100 parts by mass of the total amount of the rubber component, and the blending ratio of the crosslinking agent TRA is 1 part by mass based on 100 parts by mass of the total amount of the rubber component.

<Example 9> The same amount of xanthogen-modified CR was prepared. [Bio-Muniton viscosity ML _{1 + 4} (100 ° C) = 70, not oil-filled, manufactured by Electric Chemical Industry Co., Ltd., CR2] instead of CR1 in Table 1. A coating rubber composition was prepared in the same manner as in Example 1 except the above. The blending ratio of CR2 is 80 parts by mass in 100 parts by mass of the total amount of the rubber component, and the blending ratio of the crosslinking agent R is 1 part by mass based on 100 parts by mass of the total amount of the rubber component.

<Example 10> The same amount of sulfur-modified CR was prepared (green rubber MU _{1 + 4} (100 ° C) = 40, not oil-filled, manufactured by Electric Chemical Industry Co., Ltd., CR3) instead of CR1 in Table 1. A coating rubber composition was prepared in the same manner as in Example 1 except the above. The blending ratio of CR3 is 80 parts by mass in 100 parts by mass of the total amount of the rubber component, and the blending ratio of the crosslinking agent R is 1 part by mass based on 100 parts by mass of the total amount of the rubber component.

<Comparative Example 1> A coated rubber composition was prepared in the same manner as in Example 1 except that the CR1 in Table 1 was 25 parts by mass and the EPDM was 75 parts by mass. The blending ratio of CR1 is 25 parts by mass in 100 parts by mass of the total amount of the rubber component, and the blending ratio of the crosslinking agent R is 1 part by mass based on 100 parts by mass of the total amount of the rubber component.

<Comparative Example 2> A coated rubber composition was prepared in the same manner as in Example 1 except that CR1 in Table 1 was 100 parts by mass and EPDM was not prepared. The blending ratio of CR1 is 100 parts by mass in 100 parts by mass of the total amount of the rubber component, and the blending ratio of the crosslinking agent R is 1 part by mass based on 100 parts by mass of the total amount of the rubber component.

<Comparative Example 3> A coated rubber composition was prepared in the same manner as in Example 1 except that the crosslinking agent R in Table 1 was 0.05 parts by mass. The blending ratio of CR1 is 80 parts by mass in 100 parts by mass of the total amount of the rubber component, and the blending ratio of the crosslinking agent R is 0.05 parts by mass based on 100 parts by mass of the total amount of the rubber component.

<Comparative Example 4> A coated rubber composition was prepared in the same manner as in Example 1 except that the crosslinking agent R in Table 1 was 4.5 parts by mass. The blending ratio of CR1 is 80 parts by mass in 100 parts by mass of the total amount of the rubber component, and the blending ratio of the crosslinking agent R is 4.5 parts by mass based on 100 parts by mass of the total amount of the rubber component.

<Comparative Example 5> A coated rubber composition was prepared in the same manner as in Example 1 except that the same amount of sulfur was added (manufactured by Hosei Chemical Co., Ltd.) in place of the crosslinking agent R in Table 1. The blending ratio of CR1 is 80 parts by mass in 100 parts by mass of the total amount of the rubber component, and the blending ratio of sulfur is 1 part by mass based on 100 parts by mass of the total amount of the rubber component.

<Coke Time> The coated rubber compositions prepared in the above Examples 1 to 10 and Comparative Examples 1 to 5 were subjected to Japanese Industrial Standard JIS K6300-1:2013 "Unvulcanized Rubber - Physical Properties - 1st Part: The coking time at 125 ° C is measured by the measurement method contained in the method for calculating the viscosity and coking time of the Munni viscometer. Further, the coated rubber composition having a coking time of 7 minutes or longer was evaluated as good (○), and the coated rubber composition having a coking time of less than 7 minutes was evaluated as defective (×).

<Tensile property> The coated rubber compositions prepared in the above Examples 1 to 10 and Comparative Examples 1 to 5 were molded into a sheet having a thickness of 2 mm and crosslinked at 150 ° C for 20 minutes. The dumbbell-shaped No. 3 test piece specified in Japanese Industrial Standard JIS K6251:2010 "Vulcanized Rubber and Thermoplastic Rubber - Method for Calculating Tensile Properties" was produced by punching, and the temperature was measured according to the test method contained in the standard. The tensile strength TS (MPa) was determined by performing a tensile test under the conditions of 23 ± 2 °C. In addition, the test piece having a tensile strength TS of 16 MPa or more was evaluated as particularly good (○○), and the test piece having a tensile strength TS of less than 16 MPa and 15 MPa or more was evaluated as good (○), and tensile strength was measured. The test piece having a TS of less than 15 MPa was evaluated as defective (x).

<Ozone resistance> The coated rubber compositions prepared in the above Examples 1 to 10 and Comparative Examples 1 to 5 were molded into a sheet having a width of 52 mm × a length of 45 mm × a thickness of 2 mm and at 150 After cross-linking at ° C, the center portion of the sample was elongated by 20% in the longitudinal direction, and the fixture was used for continuous exposure to ozone at a test temperature of 40 ° C and an ozone concentration of 100 pphm. At the time, the time until a crack occurs on the surface or the side surface thereof is measured. Further, the sample having a time required for the occurrence of cracks of 1100 hours or more was evaluated as good (○), and the sample required for the time until the occurrence of cracks was less than 1100 hours was evaluated as defective (×).

<Vulcanization adhesiveness> (Production of a coating layer model) The coating rubber compositions prepared in Examples 1 to 10 and Comparative Examples 1 to 5 were molded into a width of 25 mm × a length of 150 mm × a thickness of 2 mm. In the form of a sheet, the obtained sheet is set as a model of the coating layer.

(Production of the soft layer model) The rubber component in each component shown in the following Table 2 is kneaded, and the components other than the crosslinking agent are first added to the kneaded material, and finally the crosslinking agent is added and kneaded to prepare a soft layer. Rubber composition A.

[Table 2]

Among the components in Table 2, carbon black, an anti-aging agent, zinc oxide, and stearic acid were the same as in Table 1. In addition, other components are as follows. Natural rubber: TSR20 process oil: a mixture of naphthenic asphalt and naphthenic base oil, A/O Mix manufactured by Sankyo Chemical Industry Co., Ltd. Sulfur: Manufacturing Co., Ltd., Co., Ltd. :N-cyclohexyl-2-benzothiazolylsulfenamide, Nocceler CZ-G manufactured by Ouchi Shinko Chemical Co., Ltd. (sample preparation of soft layer) The rubber composition A for the soft layer was formed The sheet having a width of 25 mm × a length of 150 mm × a thickness of 2 mm was used as a model of the soft layer.

(peel strength ratio) The model of the coating layer and the model of the soft layer were superposed so as to overlap each other at a distance of 50 mm from the end portion, and in this state, a vulcanization mold was used to cure at 150 ° C, and then a tensile test was used. The maximum peel strength was measured by performing a 180 degree peeling test under the conditions of a tensile speed of 50 mm/min. In addition, the ratio (peeling strength ratio) of the maximum peeling strength of each of the examples and the comparative examples when the maximum peeling strength of Comparative Example 1 was 100 was determined, and the sample having a peeling strength ratio of 120 or more was qualified, and the peeling was performed. The sample having an intensity ratio of less than 120 was set as a failure, and the sample having a good peel strength ratio of 130 or more was particularly excellent.

(Peeling state) In addition, the peeling surface was observed, and the sample which caused the material destruction was evaluated as a pass, and the sample which peeled the interface was evaluated as a failure. The test was carried out at N=5, and if the number of qualified samples was three or more, it was judged as pass, and if it was not, the test was made unacceptable. In addition, the sample having a particularly good peel strength ratio and a peeled state was evaluated as being particularly good (○○), and the sample having both the peel strength ratio and the peeled state was evaluated as good (○), and even if neither was Eligible samples were evaluated as poor (x).

The above results are shown in Tables 3 to 5.

[table 3]

[Table 4]

[table 5]

According to the results of Tables 3 to 5, in particular, Example 1, Example 7, Example 8, and Comparative Example 5, it can be judged that the three specific crosslinking agents are substituted for sulfur in the rubber component containing CR. The crosslinking agent can form a coating rubber composition which does not cause the crosslinking speed to be too fast to produce a scorch, and by using the coating rubber composition, it can be formed to have both tensile properties and vulcanization properties. All of the characteristics are excellent, and even if the amount of deformation is large, the rubber support of the coating layer which does not break or peels off satisfactorily follows.

However, according to the results of Examples 1 to 3, Comparative Example 1, and Comparative Example 2, it can be determined that, in order to obtain the above effect, the blending ratio of CR must be 30 parts by mass or more based on 100 parts by mass of the total amount of the rubber component. 95 parts by mass or less, preferably 60 parts by mass or more, particularly 70 parts by mass or more. Further, according to the results of Example 1, Example 4, Example 5, Comparative Example 3, and Comparative Example 4, it was judged that, in order to obtain the effect, the specific crosslinking ratio of the specific crosslinking agent must be relative to the rubber component. The total amount of 100 parts by mass is 0.1 parts by mass or more and 4 parts by mass or less, and preferably 2 parts by mass or more, particularly 3 parts by mass or more.

Further, from the results of Example 1 and Example 6, it can be judged that EPDM is preferable as the other rubber used in combination with CR as compared with bromobutyl rubber. Further, according to the results of Example 1, Example 9, and Example 10, it was confirmed that the same effect can be obtained by using any of thiol-modified CR, xanthogen-modified CR, and sulfur-modified CR as CR.

<Example 1-1, Example 1-2> A model including the following rubber composition B (Example 1-1) or rubber composition C (Example 1-2) was used as the evaluation of vulcanization adhesion. The vulcanization adhesion was evaluated in the same manner as in Example 1 except for the model of the soft layer used. (Rubber composition B) The same amount of SBR [E-SBR, bonded styrene amount center value 23.5%, unoiled, Nipol (registered trademark) 1502 manufactured by Nippon Zeon Co., Ltd.] was replaced. In addition to the natural rubber in Table 2, a rubber composition B for a soft layer was prepared in the same manner as in the rubber composition A.

(Rubber composition C) The natural rubber in Table 2 was set to 50 parts by mass, and further blended with BR [cis 1,4 bond: 95%, not oil-filled, Japan Synthetic Rubber (JSR) shares limited A rubber composition C for a soft layer was prepared in the same manner as the rubber composition A except that 50 parts by mass of JSR BR01 manufactured by the company was used.

<Example 2-1, Example 2-2> A model including the rubber composition B (Example 2-1) or the rubber composition C (Example 2-2) was used as an evaluation of vulcanization adhesion. The vulcanization adhesion was evaluated in the same manner as in Example 2 except for the model of the soft layer used. The results are shown in Table 6.

[Table 6]

According to the results of Table 6, it can be judged that when a coating rubber composition containing the CR in a predetermined ratio and having a specific crosslinking agent is used, it is possible to form a soft layer containing a rubber composition containing various rubber components. The vulcanized adhesive coating layer.

no

no

Claims (2)

A rubber support comprising: a laminate body in which a soft layer and a rigid hard layer are alternately laminated; and a coating layer covering an outer circumference of the laminate; and the coating layer comprises a coating rubber composition The coating rubber composition contains a rubber component and 0.1 parts by mass or more and 4 parts by mass or less based on 100 parts by mass of the rubber component, and is selected from the group consisting of 4,4′-dithiomorpholine and 2-(morpholine). At least one crosslinking agent in the group consisting of bisdithio)benzothiazole and dipentamethylene thiuram tetrasulfide, the total amount of the rubber component in the chloroprene rubber and at least one other rubber The chloroprene rubber is contained in a ratio of 30 parts by mass or more and 95 parts by mass or less in 100 parts by mass selected from the group consisting of ethylene-α-olefin copolymerized rubber, ethylene-α-olefin-non-conjugated At least one non-diene rubber of the group consisting of a polyene copolymer rubber and a butyl rubber. The rubber support according to claim 1, wherein the soft layer comprises a rubber composition containing a rubber selected from the group consisting of natural rubber, chloroprene rubber, styrene butadiene rubber, and butyl At least one of the groups consisting of olefin rubber is used as a rubber component.