WO2022113671A1

WO2022113671A1 - Rubber composition for hose inner tubes, laminate, and hose

Info

Publication number: WO2022113671A1
Application number: PCT/JP2021/040445
Authority: WO
Inventors: 拓也上村; 克徳紺谷
Original assignee: 株式会社ブリヂストン
Priority date: 2020-11-27
Filing date: 2021-11-02
Publication date: 2022-06-02
Also published as: JPWO2022113671A1

Abstract

The purpose of the present invention is to provide a rubber composition which is for hose inner tubes and which is capable of achieving excellent productivity and inner tube detachment resistance, even when a cobalt compound is not contained or is contained in a small amount.　In order to solve said problem, the rubber composition for hose inner tubes according to the present invention is characterized by containing, with respect to 100 parts by mass of a rubber component, A) 20 parts by mass or less of a butadiene rubber, B) 80 parts by mass or more of an acrylonitrile butadiene rubber, C) less than 10 parts by mass of silica, and D) 3.0 parts by mass or less of a non-thiazole-based vulcanization accelerator as essential components, and containing a cobalt compound as an optional component. The present invention is characterized in that the contained amount of the cobalt compound is 0.1 mass% or less in terms of the cobalt content, with respect to the total amount of the rubber composition for hose inner tubes, and in that a thiazole-based vulcanization accelerator is not contained.

Description

Rubber composition for hose inner tube, laminate and hose

The present invention relates to a rubber composition for an inner hose pipe, a rubber-metal composite, a conveyor belt, a hose, a crawler and a tire.

Conventionally, rubber products such as hoses have been composed of composite materials using metal reinforcing materials such as wires because of their required pressure resistance characteristics. Above all, in hoses such as hydraulic hoses, this metal reinforcing material exerts a high reinforcing effect, so that peeling between the metal reinforcing material and the rubber member is suppressed in order to ensure higher reliability as a product. Highly stable adhesiveness (inner tube peeling resistance) is required.

Here, as a method of bonding the above-mentioned metal reinforcing material and the rubber member, a method of simultaneously bonding the rubber and the metal, a so-called direct vulcanization bonding method, is known, and among the direct vulcanization bonding methods. , Sulfur amide-based vulcanization accelerator, which gives a delayed effect to the vulcanization reaction, is useful for simultaneously performing vulcanization of rubber and bonding with a metal.
Examples of the vulcanization accelerator currently on the market that gives a slow-acting effect to the vulcanization reaction include N, N'-dicyclohexyl-2-benzothiazolylsulfenamide, and further, the slow-acting agent is required. In such cases, a sulfenamide-based vulcanization accelerator and a vulcanization retarder such as N- (cyclohexylthio) phthalimide are also used in combination. For example, Patent Document 1 discloses a technique for containing a specific sulfenamide-based vulcanization accelerator in a rubber composition.

Further, in addition to the above-mentioned optimization of the vulcanization accelerator, a technique of blending cobalt chloride into a rubber composition is known as a technique for improving the peel resistance of the inner tube of a rubber member. By acting as an adhesive promoter, cobalt chloride can improve the peel resistance of the inner tube of the rubber member.
However, in recent years, the demand for environmentally friendly materials has been increasing, and the development of a technique capable of improving the peel resistance of the inner tube without using cobalt chloride is being promoted.

Therefore, a technique of blending a large amount of a filler in the rubber composition is known as a technique capable of enhancing the peeling resistance of the inner tube separately from the above-mentioned adhesion accelerator. By blending a filler of silica or carbon black into the rubber composition, the viscosity of the vulcanized rubber can be increased and the adhesiveness with the metal member can be enhanced.
However, when a large amount of filler is blended in the rubber composition, there is a problem that the viscosity of the rubber composition becomes too high, so that the processability is lowered and sufficient productivity cannot be obtained.

Japanese Unexamined Patent Publication No. 2011-1524

Therefore, an object of the present invention is to provide a rubber composition for a hose inner tube that can realize excellent inner tube peeling resistance and productivity even when the cobalt compound is not contained or the content is small. ..
Another object of the present invention is to provide a laminate and a hose having excellent inner tube peeling resistance and productivity even when the cobalt compound is not contained or the content is small. ..

The gist of the present invention for solving the above-mentioned problems is as follows.
The rubber composition for an inner pipe of a hose of the present invention is a rubber composition for an inner pipe of a hose.
As an essential component for 100 parts by mass of rubber component
A) 20 parts by mass or less of butadiene rubber,
B) 80 parts by mass or more of acrylonitrile butadiene rubber,
C) Less than 10 parts by mass of silica,
D) Contains 3.0 parts by mass or less of a vulcanization accelerator other than thiazole.
A cobalt compound is contained as an optional component, and the content of the cobalt compound is 0.1% by mass or less with respect to the entire rubber composition for the inner hose pipe in terms of the amount of cobalt.
It is characterized by not containing a thiazole-based vulcanization accelerator.
By providing the above configuration, excellent peel resistance and productivity of the inner tube can be realized even when the cobalt compound is not contained or the content is small.

Further, in the rubber composition for a hose inner tube of the present invention, it is preferable that the silica is contained in an amount of 2 parts by mass or more with respect to 100 parts by mass of the rubber component. This is because better inner tube peeling resistance can be realized.

Further, in the rubber composition for inner hose pipe of the present invention, it is preferable to further contain 1.5 parts by mass or less of the vulcanization retarder as an essential component with respect to 100 parts by mass of the rubber component. This is because better inner tube peeling resistance can be realized.

Furthermore, it is preferable that the rubber composition for an inner hose of the present invention contains 2.0 parts by mass or more of a vulcanization accelerator other than the thiazole-based vulcanization accelerator with respect to 100 parts by mass of the rubber component. This is because better inner tube peeling resistance can be realized.

Further, it is preferable that the vulcanization accelerator other than the thiazole-based vulcanization accelerator is a sulfenamide-based vulcanization accelerator. This is because better inner tube peeling resistance can be realized.

Further, the rubber composition for an inner hose tube of the present invention preferably further contains less than 120 parts by mass of carbon black as an essential component with respect to 100 parts by mass of the rubber component, and may contain 60 parts by mass or more and 110 parts by mass or less. More preferred. This is because better inner tube peeling resistance can be achieved without reducing productivity.

Furthermore, in the rubber composition for inner hose pipes of the present invention, the carbon black preferably contains at least one carbon black selected from FEF, GPF and SRF, and the carbon black is the carbon black of FEF. It is more preferably contained at least, and the content thereof is 70 parts by mass or more and 90 parts by mass or less with respect to 100 parts by mass of the rubber component. This is because better inner tube peeling resistance can be achieved without reducing productivity.

The laminate of the present invention is characterized by comprising a layer made of a vulcanized product of the rubber composition for an inner hose tube of the present invention described above, and a brass-plated wire.
By providing the above configuration, it is possible to have excellent inner tube peeling resistance and productivity even when the cobalt compound is not contained or the content is small.

The hose of the present invention is characterized by having a laminate of the present invention arranged on the inner side in the radial direction of the hose and an outer skin rubber layer arranged on the outermost side in the radial direction of the hose.
By providing the above configuration, it is possible to have excellent inner tube peeling resistance and productivity even when the cobalt compound is not contained or the content is small.

According to the present invention, it is possible to provide a rubber composition for a hose inner tube that can realize excellent inner tube peeling resistance and productivity even when the cobalt compound is not contained or the content is small.
Further, according to the present invention, it is possible to provide a laminate and a hose having excellent inner tube peeling resistance and productivity even when the cobalt compound is not contained or the content is small.

It is a perspective view which shows the laminated structure of the hydraulic hose which concerns on one Embodiment using the rubber composition for the hose inner pipe of this invention.

Hereinafter, embodiments of the present invention will be described. These descriptions are for the purpose of exemplifying the present invention and do not limit the present invention in any way. Further, in the present invention, two or more embodiments can be arbitrarily combined.

<Rubber composition for hose inner tube>
The rubber composition for an inner tube of a hose of the present invention is a rubber composition (rubber composition for an inner tube) used for an inner tube of a hose.
As an essential component for 100 parts by mass of rubber component
A) 20 parts by mass or less of butadiene rubber,
B) 80 parts by mass or more of acrylonitrile butadiene rubber,
C) Less than 10 parts by mass of silica,
D) Contains 3.0 parts by mass or less of a vulcanization accelerator other than thiazole.

In the present invention, the rubber composition for an inner tube to be bonded to a metal member such as a brass-plated wire contains the above-mentioned A) butadiene rubber and B) acrylonitrile butadiene rubber as rubber components, and is added other than C) silica and D) thiazole. By containing a specific amount of the sulfurization accelerator, it becomes possible to enhance the peel resistance of the inner tube due to these synergistic effects. Then, by defining the upper limit values of the C) silica content and the D) vulcanization accelerator content other than the thiazole-based, the viscosity of the rubber composition is reduced and the productivity is also improved. Can be done.

Hereinafter, the components constituting the rubber composition for the inner hose pipe of the present invention will be described.
(Rubber component)
The rubber composition for an inner hose pipe of the present invention contains a rubber component.
Regarding the rubber component, A) butadiene rubber of 20 parts by mass or less and B) acrylonitrile butadiene rubber of 80 parts by mass or more are contained with respect to 100 parts by mass of the rubber component. By containing these rubbers, it is possible to improve the peel resistance of the inner pipe while maintaining good physical properties such as oil resistance.

As the A) butadiene rubber (BR), not only polybutadiene rubber (PBR) but also butadiene rubber such as syndiotactic 1,2-polybutadiene (sPB) and high cis-butadiene rubber (high cis BR) can be used. It is possible. Only one kind of these butadiene rubbers can be used, or a plurality of kinds of butadiene rubbers can be mixed and used.
The content of the A) butadiene rubber is preferably 20 parts by mass or less with respect to 100 parts by mass of the rubber component from the viewpoint of ensuring a balance between inner tube peel resistance and productivity.

The content of B) acrylonitrile butadiene rubber (NBR) needs to be 80 parts by mass or more with respect to 100 parts by mass of the rubber component from the viewpoint of enhancing the inner tube peeling resistance and oil resistance. Further, from the viewpoint of low temperature resistance, the content of B) acrylonitrile butadiene rubber (NBR) is preferably 85 parts by mass or less.

Further, the B) acrylonitrile butadiene rubber may contain two or more types of NBR. In that case, 30 to 60 parts by mass of a so-called high acrylonitrile butadiene rubber having a nitrile content (AN content) of 40 to 45, and 20 to 50 parts by mass of a so-called medium-high acrylonitrile butadiene rubber having a nitrile content (AN content) of 30 to 40. It is preferable to include it. By blending two types of B) acrylonitrile butadiene rubber, it is possible to obtain a hose inner tube rubber having excellent physical properties such as oil resistance and cold resistance.

The rubber component may also contain a rubber component (other rubber components) other than the above-mentioned A) butadiene rubber and B) acrylonitrile butadiene rubber.
Examples of the other rubber components include natural rubber (NR), isoprene rubber (IR), styrene butadiene rubber (SBR), styrene isoprene butadiene rubber (SIBR), ethylene propylene diene rubber (EPDM), and chloroprene rubber (CR). , Butyl rubber (IIR), modified products thereof and the like can be used. These other rubber components may be used alone or in combination of two or more.

(filler)
In addition to the rubber component described above, the rubber composition for an inner hose tube of the present invention contains C) silica of less than 10 parts by mass with respect to 100 parts by mass of the rubber component as a filler.
By containing the above-mentioned C) silica as a filler, the adhesiveness of the rubber composition can be enhanced and the peel resistance of the inner tube can be improved.

The type of silica is not particularly limited. For example, wet silica (hydrous silicic acid), dry silica (anhydrous silicic acid), calcium silicate, aluminum silicate and the like can be used. Among these, it is preferable to use wet silica.
Further, the BET specific surface area (measured based on ISO5794 / 1) of the wet silica is preferably about 100 to 300 m ² / g. Silica having a BET specific surface area in this range can further improve the inner tube peel resistance without lowering the productivity. The silica may be used alone or in combination of two or more.

The content of the silica is less than 10 parts by mass with respect to 100 parts by mass of the rubber component. When the content of the silica is 10 parts by mass or more with respect to 100 parts by mass of the rubber component, the viscosity of the rubber composition may increase and the productivity may decrease. From the same viewpoint, the content of the silica is preferably 9 parts by mass or less, and more preferably 7 parts by mass or less with respect to 100 parts by mass of the rubber component.
Further, the content of the silica is preferably 2 parts by mass or more, and preferably 3 parts by mass or more with respect to 100 parts by mass of the rubber component, from the viewpoint of more reliably improving the peel resistance of the inner tube. More preferred.

Further, it is preferable that the filler contains carbon black as an essential component. This is because the inner pipe peeling resistance of the rubber composition for the inner pipe of the hose can be further improved, and the durability can also be improved.
The content of the carbon black is not particularly limited, but is less than 120 parts by mass with respect to 100 parts by mass of the rubber component from the viewpoint of further improving the peel resistance of the inner tube without lowering the productivity. It is preferably 110 parts by mass or less, more preferably 100 parts by mass or less, and further preferably 100 parts by mass or less. Further, the content of the carbon black is preferably 60 parts by mass or more, and 70 parts by mass or more with respect to 100 parts by mass of the rubber component, from the viewpoint of more reliably enhancing the peel resistance of the inner tube. Is preferable.

Here, the type of carbon black is not particularly limited. For example, grade carbon blacks such as FEF, GPF, SRF, HAF, ISAF, SAF and the like can be used. Among these, the carbon black preferably contains at least one carbon black selected from FEF, GPF and SRF, and more preferably contains at least FEF carbon black. This is because the inner tube peeling resistance can be improved more reliably.
Further, when the carbon black is FEF carbon black, the content thereof is preferably 70 parts by mass or more and 90 parts by mass or less with respect to 100 parts by mass of the rubber component. When the carbon black content of the FEF is 70 parts by mass or more with respect to 100 parts by mass of the rubber component, the inner tube peeling resistance and strength can be more reliably increased, and 100 parts by mass of the rubber component can be used. On the other hand, in the case of 90 parts by mass or less, it is possible to suppress deterioration of productivity and low heat generation.

Regarding the filler, in addition to C) silica and carbon black, for example, aluminum hydroxide, clay, alumina, talc, mica, kaolin, glass balloon, glass beads, calcium carbonate, magnesium carbonate, and hydroxide. It can contain an inorganic filler such as magnesium, magnesium oxide, titanium oxide, potassium titanate, barium sulfate and the like.

(Vulcanization accelerator)
The rubber composition for an inner hose tube of the present invention contains, in addition to the above-mentioned rubber component and filler, a vulcanization accelerator other than D) thiazole-based, which is 3.0 parts by mass or less with respect to 100 parts by mass of the rubber component.
By containing D) a vulcanization accelerator other than the thiazole-based vulcanization accelerator as the vulcanization accelerator, it becomes possible to simultaneously vulcanize the rubber and bond the metal, and the adhesive performance between the rubber and the metal is enhanced. , The peel resistance of the inner tube can be improved. When a thiazole-based vulcanization accelerator is contained as the vulcanization accelerator, it is difficult to simultaneously vulcanize rubber and bond with a metal, and sufficient inner tube peeling resistance cannot be obtained. The rubber composition containing a thiazole-based vulcanization accelerator shall be excluded from the rubber composition. That is, the rubber composition of the present invention does not contain a thiazole-based vulcanization accelerator.

Here, regarding the vulcanization accelerator other than D) thiazole-based, for example, sulfenamide-based, thiuram-based, dithiocarbamate-based, xanthogenate-based, guanidine-based, thiourea-based, aldehyde-ammonia-based, aldehyde- Examples thereof include amine-based vulcanization accelerators.
Among these, it is preferable that the vulcanization accelerator other than D) thiazole-based is a sulfenamide-based vulcanization accelerator. This is because the vulcanization reaction can be delayed and the rubber vulcanization and the metal are effectively bonded, so that more excellent inner tube peeling resistance can be realized.

The sulfenamide-based sulfide accelerating agent is not particularly limited, but for example, N-cyclohexyl-2-benzothiazolylsulfenamide (CZ) and Nt-butyl-2-benzothiazolylsulfen. Amid (NS), N-methyl-Nt-butylbenzothiazole-2-sulfenamide (BMBS), N-ethyl-Nt-butylbenzothiazole-2-sulfenamide (BEBS), Nn -Propyl-N-t-butylbenzothiazole-2-sulfenamide, Nn-butyl-Nt-butylbenzothiazole-2-sulfenamide (BBBS), N-methyl-N-isoamylbenzothiazole- 2-Sulfenamide, N-ethyl-N-isoamylbenzothiazole-2-sulfenamide, Nn-propyl-N-isoamylbenzothiazole-2-sulfenamide, Nn-butyl-N-isoamylbenzo Thiazol-2-sulfenamide, N-methyl-N-tert-amylbenzothiazole-2-sulfenamide, N-ethyl-N-tert-amylbenzothiazole-2-sulfenamide, N-n-propyl- N-tert-amylbenzothiazole-2-sulfenamide, Nn-butyl-N-tert-amylbenzothiazole-2-sulfenamide, N-methyl-N-tert-heptylbenzothiazole-2-sulfenamide Amid, N-ethyl-N-tert-heptylbenzothiazole-2-sulfenamide, Nn-propyl-N-tert-heptylbenzothiazole-2-sulfenamide, Nn-butyl-N-sulfenamide- Heptylbenzothiazole-2-sulfenamide, N-methyl-Nt-butyl-4-methylbenzothiazole-2-sulfenamide, N-methyl-Nt-butyl-4,6-dimethoxybenzothiazole- 2-Sulfenamide, N-ethyl-Nt-butyl-4-methylbenzothiazole-2-sulfenamide, N-ethyl-Nt-butyl-4,6-dimethoxybenzothiazole-2-sulfen Amid, Nn-propyl-Nt-butyl-4-methylbenzothiazole-2-sulfenamide, Nn-propyl-Nt-butyl-4,6-dimethoxybenzothiazole-2-sulfenamide Amid, Nn-butyl-Nt-butyl-4-methylbenzothiazole-2-sulfenamide, Nn-butyl-Nt -Butyl-4,6-dimethoxybenzothiazole-2-sulfenamide and the like can be mentioned. These may be used individually by 1 type, or may be used by mixing 2 or more types.
Among these, the sulfenamide-based vulcanization accelerators are N-cyclohexyl-2-benzothiazolyl sulfenamide (CZ) and Nt- from the viewpoint of achieving better inner tube peel resistance. It is preferable to use at least one of butyl-2-benzothiazolylsulfenamide (NS).

The content of the vulcanization accelerator other than D) thiazole-based is 3.0 parts by mass or less with respect to 100 parts by mass of the rubber component. If the content of the vulcanization accelerator other than D) thiazole-based exceeds 3.0 parts by mass with respect to 100 parts by mass of the rubber component, the progress rate of vulcanization becomes too fast, so that the inner tube is sufficiently resistant to peeling. You may not be able to get sex. From the same viewpoint, the content of the vulcanization accelerator other than D) thiazole-based is preferably 2.9 parts by mass or less, and 2.5 parts by mass or less with respect to 100 parts by mass of the rubber component. Is preferable.
Further, the content of the vulcanization accelerator other than D) thiazole-based is 100 mass of rubber component from the viewpoint of more reliably realizing the bond between the vulcanization of rubber and the metal and obtaining more excellent inner tube peeling resistance. It is preferably 1.3 parts by mass or more, more preferably 2.0 parts by mass or more, and further preferably 2.1 parts by mass or more.

(Cobalt compound)
Further, the rubber composition for an inner hose tube of the present invention may contain a cobalt compound as an optional component. By containing the cobalt compound, improvement in peel resistance of the inner tube can be expected.
However, from the viewpoint of consideration for the environment, the content of the cobalt compound needs to be 0.1% by mass or less with respect to the entire rubber composition for the inner hose pipe in terms of the amount of cobalt. It is preferably 05% by mass or less, and particularly preferably 0% (not contained).

The cobalt compound is a compound containing cobalt, and examples thereof include cobalt metal, cobalt oxide, cobalt chloride, cobalt sulfate, cobalt nitrate, cobalt phosphate, cobalt chromate, and cobalt organic acid. ..

(Other ingredients)
The rubber composition for an inner hose pipe of the present invention appropriately contains a rubber component as an essential component, a filler and a vulcanization accelerator, and a component (other components) other than a cobalt compound as an optional component. Can be done. Such other components include, for example, bismaleimide compounds, sulfur, vulcanization retarders, vulcanization accelerators, antioxidants, thermoplastics, petroleum resins, waxes, antioxidants, oils, lubricants, UV absorbers. , Dispersant, compatibilizer, co-crosslinking agent, homogenizing agent and the like.

The rubber composition for an inner hose tube of the present invention may contain a bismaleimide compound as another component. Here, examples of the bismaleimide compound include a bismaleimide compound represented by the following general formula (I).

By containing the bismaleimide compound represented by the general formula (I) in the rubber composition for the inner tube of the hose, the adhesiveness can be enhanced and the peelability of the inner tube can be improved.

In the above general formula (I), A represents a divalent aromatic group having 6 to 18 carbon atoms or a divalent alkyl aromatic group having 7 to 24 carbon atoms, and x and y are respectively. Independently represents an integer from 0 to 3.
Further, in the bismaleimide compound represented by the above general formula (I), x or y is an integer of 0 to 3, but when it is 4 or more, the molecular weight becomes too large and the compounding amount is increased. It is inconvenient because the desired effect of improving the inner tube peelability cannot be obtained.

Here, specific examples of the bismaleimide compound represented by the above general formula (I) include, for example, N, N'-1,2-phenylenedimaleimide, N, N'-1,3-phenylenedimaleimide, and the like. N, N'-1,4-phenylenedimoleimide, N, N'-(4,4'-diphenylmethane) bismaleimide, 2,2-bis [4- (4-maleimide phenoxy) phenyl] propane, bis (3) -Ethyl-5-methyl-4-maleimidephenyl] methane and the like can be preferably mentioned. These bismaleimide compounds may be blended in one or more kinds.
Further, among these bismaleimide compounds, N, N'-1,2-phenylenedi maleimide, N, N'-1,3-phenylenedi maleimide or N, N'-1,4-phenylenedi maleimide is used. It is preferable, and it is more preferable to contain at least N, N'-(4,4'-diphenylmethane) bismaleimide.

The content of the bismaleimide compound in the rubber composition for an inner hose tube of the present invention is preferably 1 part by mass or more with respect to 100 parts by mass of the rubber component. This is because the content of the bismaleimide compound is 0.5% by mass or more with respect to 100 parts by mass of the rubber component, so that the adhesive strength of the rubber composition can be enhanced and the inner tube peelability can be further enhanced. From the same viewpoint, the content of the bismaleimide compound is more preferably 1 part by mass or more with respect to 100 parts by mass of the rubber component.
Further, from the viewpoint of more reliably suppressing the decrease in the inner tube peelability due to excessive curing, the content of the bismaleimide compound is preferably 5 parts by mass or less with respect to 100 parts by mass of the rubber component. It is more preferably less than the mass part.

The rubber composition for an inner hose tube of the present invention usually contains sulfur as a vulcanizing agent. The content thereof is not particularly limited, but is preferably 0.3 to 10 parts by mass, more preferably 1.0 to 7.0 parts by mass with respect to 100 parts by mass of the rubber component. It is more preferably 2.0 to 5.0 parts by mass. When the sulfur content is 0.3 parts by mass or more with respect to 100 parts by mass of the rubber component, vulcanization can be sufficiently performed, and 10 parts by mass or less with respect to 100 parts by mass of the rubber component. , It is possible to suppress the deterioration of the aging performance of rubber.

Further, among the other components, the rubber composition for an inner tube of the present invention preferably further contains a vulcanization retarder as an essential component from the viewpoint of achieving better inner tube peel resistance. By the action of the vulcanization retarder, the vulcanization of the rubber and the bonding with the metal can be performed more reliably, and the adhesive performance between the rubber and the metal can be further enhanced.
The content of the vulcanization retarder is not particularly limited. For example, from the viewpoint that the inner tube peeling resistance can be more reliably improved without adversely affecting the productivity, the content of the vulcanization retarder is 1.5 mass by mass with respect to 100 parts by mass of the rubber component. The content is preferably parts or less, and more preferably 1.3 parts by mass or less.

As a method for obtaining the rubber composition for an inner hose pipe of the present invention, for example, each of the above-mentioned components can be obtained by kneading with a Banbury mixer, a kneader or the like.

<Laminated body>
The laminate of the present invention is characterized by comprising a layer made of a vulcanized product of the rubber composition for an inner hose tube of the present invention described above, and a brass-plated wire.
By providing the layer made of the vulcanized product of the rubber composition for the inner pipe of the hose of the present invention, excellent peel resistance and productivity of the inner pipe are realized even when the cobalt compound is not used or the content is small. can.

The rubber composition for the inner hose pipe is as described above.
Further, the conditions for vulcanizing the rubber composition for the inner hose tube are not particularly limited and can be adjusted according to the required performance. For example, a layer made of the vulcanized product can be obtained by performing a vulcanization treatment at 100 to 200 ° C. for 10 to 100 minutes.

Further, the brass-plated wire constituting the laminated body of the present invention is not particularly limited and can be appropriately selected according to the required performance.
Further, in the laminated body of the present invention, the brass-plated wire can be knitted into layers. When the laminate of the present invention is used for a hose, the layer made of the braided brass-plated wire constitutes a reinforcing layer. The method of knitting the brass-plated wire is not particularly limited, and can be appropriately selected depending on the use of the laminated body. For example, it can be knitted into a spiral shape or a blade shape.

Furthermore, in the laminated body of the present invention, it is also possible to knit the brass-plated wire in combination with organic fibers. In that case, as the organic fiber, aramid fiber, polyester fiber, polyarylate fiber, nylon fiber, vinylon fiber, polyethylene terephthalate fiber, polyethylene naphthalate fiber, ultrahigh molecular weight polyethylene fiber, carbon-based fiber and the like can be used.

<Hose>
The hose of the present invention is characterized by having a laminate of the present invention arranged on the inner side in the radial direction of the hose and an outer skin rubber layer arranged on the outermost side in the radial direction of the hose.
By arranging the laminate of the present invention inside in the radial direction of the hose, excellent inner tube peeling resistance and productivity can be realized even when the cobalt compound is not used or the content is small.

As the hose of the present invention, for example, as shown in FIG. 1, a rubber inner surface rubber layer 2 (inner tube rubber) filled with hydraulic oil, a reinforcing layer 3 for withstanding the pressure of the hydraulic oil, and reinforcement thereof. The hydraulic hose 1 can be formed by sequentially laminating an outer surface rubber layer 4 (cover rubber) that prevents the layer 3 and the inner surface rubber layer 2 from being damaged.
In this case, in the above-mentioned laminated body of the present invention, the vulcanized product of the rubber composition for the inner pipe of the hose constitutes the inner surface rubber layer 2, and the brass-plated wire constitutes the reinforcing layer 3.

When the hydraulic hose 1 is manufactured, it can be manufactured by the method shown below.
First, the rubber composition for an inner tube of the hose of the present invention is extruded on the outside of a core body (mandrel) having a diameter similar to the inner diameter of the hose to coat the mandrel to form an inner rubber layer (inner tube rubber) 2. (Inner tube extrusion process). Next, a predetermined number of brass-plated wires are knitted on the outside of the inner surface rubber layer 2 formed in the inner pipe extrusion step, and the reinforcing layer 3 is laminated (knitting step), and the outer cover of the hose is on the outside of the reinforcing layer 3. The rubber composition to be used is extruded to form an outer surface rubber layer (outer rubber) 4 (outer cover extrusion step). Further, the outside of the outer surface rubber layer 4 formed in the outer cover extrusion step is coated with a resin (resin mold coating step), and this is vulcanized under normal conditions (vulcanization step). After vulcanization, the coating resin is peeled off (resin mold peeling step) and the mandrel is removed (mandrel extraction step), so that the hydraulic hose 1 having a reinforcing layer 3 between the inner tube rubber 2 and the outer cover rubber 4 Will be.

The structure of the hydraulic hose 1 may be a three-layer structure in which the inner tube rubber 2, the reinforcing layer 3 and the outer cover rubber 4 are sequentially laminated from the inside as described above, and especially when strength or the like is required. Although not shown, the reinforcing layer may be two layers, and an intermediate layer (intermediate rubber) may be arranged between the reinforcing layers of the two layers to form a five-layer structure, and these structures are appropriately used according to the required characteristics of the hose and the like. Just set it.

Examples of the intermediate rubber include ethylene-propylene copolymer rubber (EPM), ethylene-propylene-diene ternary copolymer rubber (EPDM), acrylic rubber (ACM), chloroprene rubber (CR), and chlorosulfonated polyethylene rubber. Hydrin rubber, styrene-butadiene copolymer rubber (SBR), acrylonitrile-butadiene copolymer rubber (NBR), isobutylene-isoprene copolymer rubber (IIR), natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR) , Urethane-based rubber, silicone-based rubber, fluorine-based rubber, and the like. These rubber components can be used alone or as any blend of two or more.

Further, the intermediate rubber does not impair the object of the present invention by using known rubber compounding chemicals and rubber fillers generally used in the rubber industry in consideration of material strength, durability, extrusion moldability and the like. Can be used in the range. Examples of such compounding chemicals and fillers include inorganic fillers such as carbon black, silica and calcium carbonate; process oils, plasticizers and softeners; vulcanizers such as sulfur; addition of zinc oxide and stearic acid. Vulcanization aid; Vulcanization accelerator such as dibenzothiazyl disulfide; Anti-aging agent such as N-cyclohexyl-2-benzothiazyl-sulfurenamide, N-oxydiethylene-benzothiazyl-sulfurphenamide; Antioxidant, Anti-sulfur deterioration Additives such as agents; etc. can be appropriately used. One of these compounding chemicals and fillers may be used alone, or two or more thereof may be used in combination.

The outer cover rubber may be made of, for example, a layer made of a thermoplastic resin or the like, or may be made of the various rubbers, in the same manner as those used for conventional hydraulic hoses. By providing the outer skin rubber layer, the fibers constituting the reinforcing layer are protected, damage to the reinforcing layer can be prevented, and the appearance is also preferable.

Hereinafter, the present invention will be described in more detail with reference to examples, but these examples are for the purpose of exemplifying the present invention and do not limit the present invention in any way. In the examples, the blending amount means parts by mass unless otherwise specified.

(Samples 1-41)
According to the formulations shown in Tables 1 and 2, kneading was performed using a normal Banbury mixer to prepare each sample of the rubber composition for the hose inner tube. The content of each component in Tables 1 and 2 is shown by the amount (parts by mass) with respect to 100 parts by mass of the rubber component.

(evaluation)
The following evaluations were performed on each sample of the obtained rubber composition. The evaluation results are shown in Table 1.

(1) Mooney Viscosity The rubber composition for the inner hose tube of each sample was measured for Mooney viscosity in accordance with JIS K 630-1 (2001) "Mooney Viscosity, Mooney Scorch Time".
The measurement results of the measured Mooney viscosity are shown in Tables 1 and 2. The smaller the value, the smaller the unvulcanized viscosity, and the larger the value, the harder it is. The range between 65 and 110 is acceptable in the production process. The range from 65 to 93 indicates that the productivity is particularly good.

(2) Wire pulling force The rubber composition for the inner hose tube of each sample is heat-kneaded with two test rolls to prepare a rubber sheet, and a plurality of rubber pieces having a width of 10 mm and a length of 120 mm are cut out from the rubber sheet. rice field. After that, a brass-plated wire of φ0.6 mm × 100 mm plated with brass (Cu65%, Zn35%) was used with the two rubber pieces, and the total thickness of the upper rubber piece was 8 mm and the total thickness of the lower rubber piece. Was sandwiched to 6 mm and vulcanized at 150 ° C. for 60 minutes to prepare a test sample having a wire embedding length of 10 mm. The obtained test sample was subjected to a pull-out test by a method according to ASTM D2229, and the force required for pull-out (pull-out force (N)) was measured.
As for the wire pulling force, the larger the value, the larger the adhesive force between the rubber and the wire, and the better the inner tube peeling resistance.

(3) 100% Modulus A vulcanized rubber was prepared from the rubber composition for the hose inner tube of each sample under vulcanization conditions at 150 ° C. for 60 minutes, and each vulcanized rubber was put into a dumbbell-shaped No. 3 test piece. It was processed and 100% modulus (MPa) was measured according to JIS K 6251 (2010).
The measurement results of 100% modulus are shown in Tables 1 and 2, and the larger the value, the better the elastic modulus.

(4) Permanent compression strain (Cs)
A vulcanized rubber was prepared from the rubber composition for the inner hose of each sample under vulcanization conditions of 150 ° C. for 60 minutes, and each vulcanized rubber was subjected to permanent compression strain according to the measurement method specified in JIS-K6301. (Cs) was measured. The compression conditions were a temperature of 100 ° C., a compression rate of 25%, and a compression time of 72 hours.
The measurement results of the permanent compression strain (Cs) are shown in Tables 1 and 2, and the smaller the value, the better the permanent compression strain.

(5) Fracture elongation (Eb)
A vulcanized rubber was prepared from the rubber composition for the inner hose of each sample under vulcanization conditions at 150 ° C. for 60 minutes, and each vulcanized rubber was processed into a dumbbell-shaped No. 3 test piece, and a tensile test device was used. (Eb) was measured using (Shimadzu Seisakusho Co., Ltd.). Specifically, the test piece is pulled at a speed of 500 mm / min at 25 ° C., the length when the test piece breaks is measured, and the length (%) with respect to the length (100%) before pulling is calculated. Calculated.
The measurement results of the elongation at break (Eb) are shown in Tables 1 and 2, and the larger the value, the better the elongation at break.

* 1: Polybutadiene rubber, manufactured by Ube Kosan Co., Ltd. "UBEPOL VCR (registered trademark)"
* 2: "JSR N220S" manufactured by JSR Corporation
* 3: "JSR N230S" manufactured by JSR Corporation
* 4: SRF grade carbon black, "Asahi # 50" manufactured by Asahi Carbon Co., Ltd.
* 5: FEF grade carbon black, "Asahi # 65" manufactured by Asahi Carbon Co., Ltd.
* 6: VA-GPF grade carbon black, manufactured by Asahi Carbon Co., Ltd. "Asahi # 55"
* 7: "Nipsil AQ" manufactured by Tosoh Silica Co., Ltd.
* 8: "Salfax (registered trademark) 5" manufactured by Tsurumi Chemical Industry Co., Ltd.
* 9: N-Cyclohexyl-2-benzothiazolyl sulfenamide, manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd. Product name "Noxeller CZ-G"
* 10: Benzodiazepine disulfide, "Noxeller DM-P" manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.
* 11: Nt-Butyl-2-benzothiadylsulfenamide, manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd. "Noxeller NS-P"
* 12: N- (cyclohexylthio) phthalimide, manufactured by Kawaguchi Chemical Industry Co., Ltd. "Anscoach CTP"
* 13: N, N'-m-phenylene bismaleimide (N, N'-1,3-phenylenedi maleimide), manufactured by Daiwa Kasei Kogyo Co., Ltd. "BMI-3000H"

From the results in Tables 1 and 2, it can be seen that for each sample of the example, all the evaluation items show well-balanced and excellent results. On the other hand, for each sample of the comparative example, it can be seen that at least one evaluation item shows inferior results as compared with the examples.

According to the present invention, it is possible to provide a rubber composition for a hose inner tube that can realize excellent inner tube peeling resistance and productivity.
Further, according to the present invention, it is possible to provide a laminate and a hose having excellent inner tube peeling resistance and productivity.

1 Hydraulic hose 2 Inner surface rubber layer (inner tube rubber)
3 Reinforcing layer 4 Outer surface rubber layer (outer cover rubber)

Claims

A rubber composition for the inner pipe of a hose.
As an essential component for 100 parts by mass of rubber component
A) 20 parts by mass or less of butadiene rubber,
B) 80 parts by mass or more of acrylonitrile butadiene rubber,
C) Less than 10 parts by mass of silica,
D) Contains 3.0 parts by mass or less of a vulcanization accelerator other than thiazole.
A cobalt compound is contained as an optional component, and the content of the cobalt compound is 0.1% by mass or less with respect to the entire rubber composition for the inner hose pipe in terms of the amount of cobalt.
A rubber composition for an inner hose tube, which does not contain a thiazole-based vulcanization accelerator.
The rubber composition for an inner hose pipe according to claim 1, wherein the silica is contained in an amount of 2 parts by mass or more with respect to 100 parts by mass of the rubber component.
The rubber composition for an inner hose according to claim 1 or 2, wherein the vulcanization retarder is further contained in an essential component of 1.5 parts by mass or less with respect to 100 parts by mass of the rubber component.
The rubber composition for an inner hose according to any one of claims 1 to 3, wherein the rubber component contains 2.0 parts by mass or more of a vulcanization accelerator other than the thiazole-based vulcanization accelerator with respect to 100 parts by mass of the rubber component. thing.
The rubber composition for an inner hose pipe according to any one of claims 1 to 4, wherein the vulcanization accelerator other than the thiazole-based vulcanization accelerator is a sulfenamide-based vulcanization accelerator.
The rubber composition for an inner hose pipe according to any one of claims 1 to 5, wherein the rubber component further contains less than 120 parts by mass of carbon black as an essential component with respect to 100 parts by mass of the rubber component.
The rubber composition for an inner hose pipe according to claim 6, wherein the carbon black is contained in an amount of 60 parts by mass or more and 110 parts by mass or less with respect to 100 parts by mass of the rubber component.
The rubber composition for an inner hose pipe according to claim 6 or 7, wherein the carbon black contains at least one carbon black selected from FEF, GPF and SRF.
The hose according to claim 8, wherein the carbon black contains at least carbon black of FEF, and the content thereof is 70 parts by mass or more and 90 parts by mass or less with respect to 100 parts by mass of the rubber component. Rubber composition for tubes.
A laminate comprising a layer made of a vulcanized product of the rubber composition for an inner hose pipe according to any one of claims 1 to 9 and a brass-plated wire.
A hose comprising the laminate according to claim 10 arranged inside in the radial direction of the hose and an outer skin rubber layer arranged outside in the radial direction of the hose.