JP6754232B2 - Hose and its manufacturing method - Google Patents

Description

The present invention relates to a hose and a method for manufacturing the hose, which is useful as a fuel hose, an oil hose, an air hose, etc. for automobiles.

Acrylonitrile butadiene rubber is widely used as an inner layer rubber for automobile fuel hoses, oil hoses, air hoses, etc. because of its high oil resistance and sealing property. However, acrylonitrile butadiene rubber has drawbacks such as poor ozone resistance and weather resistance. Therefore, for the outer layer rubber of the hose, for example, chloroprene rubber having excellent ozone resistance and weather resistance is used.

However, since the vulcanization adhesiveness between the inner layer made of acrylonitrile butadiene rubber and the outer layer made of chloroprene rubber is poor, the applicant has applied, for example, acrylonitrile butadiene as a layer having excellent adhesiveness to both layers. We have proposed a method of enhancing the interlayer adhesiveness by interposing an adhesive layer made of a mixed rubber of rubber and chloroprene rubber (see Patent Document 1).

JP-A-2007-32807

However, in the adhesive used as the material of the adhesive layer as described above, rubber, which is an adhesive component, is usually dissolved in a solvent belonging to Class 4 Class 1 Petroleum, which is a dangerous substance, such as toluene, xylene, and methyl ethyl ketone. It is a solvent. Therefore, (1) volatile organic compounds (VOC) are generated in the manufacturing process, which leads to deterioration of the working environment, (2) vulcanization becomes sweet due to excessive swelling and dissolution of rubber, and (3) at the adhesive interface. There remains a problem that the remaining solvent swells at the time of depressurization and easily causes delamination.

Not only when the inner layer rubber and the outer layer rubber are different as in the hose disclosed in Patent Document 1, but also in a hose using the same type of rubber as the inner layer rubber and the outer layer rubber, an adhesive is required between the layers. Since there are cases, it is desired to solve the above problems for such hoses.

Further, as a conventional adhesive method, there is also a method of adding an adhesive component to a rubber composition which is a material for forming an inner layer or an outer layer, but this method may deteriorate the performance of rubber.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a hose and a method for producing the hose, in which the generation of volatile organic compounds (VOCs) is suppressed in the production process and the interlayer adhesiveness is excellent. ..

In order to achieve the above object, the present invention presents a tubular inner layer composed of at least one of a nitrile rubber composition and a halogen rubber composition, and a nitrile rubber composition and a halogen type provided on the outer periphery of the inner layer. It is provided with an outer layer composed of at least one of the rubber compositions, and the layer between the inner layer and the outer layer is a welded surface by a liquid agent having a solvent component represented by the following general formula (1) of 95 to 100% by weight . The hose is the first gist.

Further, the present invention is the method for producing a hose according to the first gist, which comprises a step of extrusion-molding a rubber composition for forming an inner layer, which is at least one of a nitrile-based rubber composition and a halogen-based rubber composition, into a tubular shape. A step of applying a liquid agent having a solvent component represented by the following general formula (1) of 95 to 100% by weight on the outer peripheral surface of the rubber composition layer for forming an inner layer obtained by the above extrusion molding, and the above-mentioned liquid agent coating. A step of extruding a tubular rubber composition for forming an outer layer, which is at least one of a nitrile-based rubber composition and a halogen-based rubber composition, on the outer peripheral surface of the rubber composition layer for forming an inner layer, and the above-mentioned extrusion molding. The second gist is a method for manufacturing a hose, which comprises a step of heating and sulphurizing a rubber composition layer for forming an inner layer and a rubber composition layer for forming an outer layer.

That is, the present inventors have conducted intensive studies to solve the above problems. In the process of the research, as a solvent for the adhesive layer provided between the inner layer and the outer layer made of nitrile rubber such as acrylonitrile butadiene rubber (NBR) and halogen rubber such as chloroprene rubber (CR), VOC is less generated. Considered using. However, it is difficult to dissolve the rubber in the inner layer and the rubber in the outer layer with a conventional solvent (isoparaffin-based solvent, etc.) known to generate less VOC, and it is possible to realize strong welding of both layers. could not. Therefore, the present inventors have conducted further studies, and as a result, when a liquid agent having a solvent component of 95 to 100% by weight represented by the above general formula (1) is used, the generation of VOC is suppressed and both layers are formed. We have found that it can be firmly welded and can solve the problem of delamination after hose production, and arrived at the present invention.

The hose of the present invention comprises a tubular inner layer composed of at least one of a nitrile rubber composition and a halogen rubber composition, and at least one of the nitrile rubber composition and the halogen rubber composition provided on the outer periphery of the inner layer. The hose is provided with an outer layer, and the layer between the inner layer and the outer layer is a welded surface with a liquid agent containing 95 to 100% by weight of the solvent component represented by the general formula (1). Therefore, good interlayer adhesion can be realized while suppressing the generation of VOC in the manufacturing process. Further, the hose of the present invention is excellent in oil resistance, sealing property, ozone resistance and weather resistance due to its layer structure, and further, since it has high interlayer adhesiveness as described above, it has pressure resistance and repeated pressure durability. Excellent hose performance such as negative pressure. Therefore, it can be widely used as a fuel hose, an oil hose, an air hose, etc. for automobiles.

In particular, if an adhesive layer made of an adhesive containing the solvent component represented by the general formula (1) and a nitrile rubber is provided between the inner layer and the outer layer, the interlayer adhesiveness between the inner layer and the outer layer may cause a problem. Become superior.

Further, when the polymer of the rubber composition constituting the inner layer contains 60% by weight or more of nitrile rubber, it becomes more excellent in oil resistance, sealing property and the like.

Further, when the polymer of the rubber composition constituting the outer layer contains 60% by weight or more of halogen-based rubber, it becomes more excellent in ozone resistance, weather resistance and the like.

Then, the step of extrusion-molding the rubber composition for forming an inner layer, which is at least one of the nitrile-based rubber composition and the halogen-based rubber composition, into a tubular shape, and the outer peripheral surface of the rubber composition layer for forming an inner layer obtained by the extrusion molding. In addition, a step of applying a liquid agent having a solvent component of 95 to 100% by weight represented by the following general formula (1) and a nitrile-based rubber composition on the outer peripheral surface of the rubber composition layer for forming an inner layer to which the liquid agent is applied. The step of extruding the rubber composition for forming the outer layer, which is at least one of the product and the halogen-based rubber composition, into a tubular shape, and heating the extruded rubber composition layer for forming the inner layer and the rubber composition layer for forming the outer layer. When the hose of the present invention is manufactured by a manufacturing method including a step of brewing the rubber, the generation of VOC in the manufacturing process can be suppressed, which can greatly contribute to the improvement of the working environment and the local environment. Further, by the above manufacturing method, the hose of the present invention having excellent performance as described above can be manufactured more efficiently.

Further, when the liquid agent used in the manufacturing method contains only the solvent component represented by the general formula (1), it becomes more excellent in terms of workability and the like.

Further, when the liquid agent used in the production method is an adhesive containing the solvent component represented by the general formula (1) and a nitrile rubber, the interlayer adhesiveness between the inner layer and the outer layer becomes more excellent.

It is explanatory drawing which shows an example of the layer structure of the hose of this invention schematically. It is explanatory drawing which showed the other example of the layer structure of the hose of this invention schematically.

Next, embodiments of the present invention will be described in detail. However, the present invention is not limited to this embodiment.

As described above, the hose of the present invention has a tubular inner layer composed of at least one of a nitrile-based rubber composition and a halogen-based rubber composition, and a nitrile-based rubber composition and a halogen-based hose provided on the outer periphery of the inner layer. A hose having an outer layer composed of at least one of the rubber compositions, in which the layers between the inner layer and the outer layer are welded surfaces by a liquid agent having a solvent component represented by the following general formula (1) of 95 to 100% by weight. It has become.

The hose shown in FIG. 1 is an example of the hose of the present invention, and is provided in contact with an inner layer 1 composed of at least one of a nitrile rubber composition and a halogen rubber composition and an outer peripheral surface of the inner layer 1. It includes an outer layer 2 composed of at least one of a rubber composition and a halogen rubber composition. Although not clearly shown in FIG. 1, the layer between the inner layer 1 and the outer layer 2 is a welded surface by a liquid agent having a solvent component represented by the general formula (1) of 95 to 100% by weight. There is. Here, the welded surface is a surface in which the outer peripheral surface of the inner layer 1 and the inner peripheral surface of the outer layer 2 are dissolved by the solvent component and welded. The welded surface can be formed, for example, by applying only the solvent component represented by the general formula (1) between the inner layer 1 and the outer layer 2, but in order to further enhance the interlayer adhesiveness, the general formula (1) Even if the welded surface is formed by applying an adhesive obtained by dissolving rubber in the solvent component shown in 1) between the above layers and providing an adhesive layer between the inner layer 1 and the outer layer 2. Good. When the adhesive layer is formed as described above, the thickness thereof is preferably 200 μm or less from the viewpoint of the strength of the adhesive layer itself. Further, as the rubber contained in the adhesive, a nitrile rubber is preferable from the viewpoint of further enhancing the interlayer adhesiveness. The nitrile rubber is preferably an NBR rubber such as acrylonitrile butadiene rubber (NBR), hydrogenated acrylonitrile butadiene rubber (H-NBR), and a blend polymer of acrylonitrile butadiene rubber and polyvinyl chloride (NBR / PVC). Is used. The amount of bonded nitrile in the nitrile rubber is preferably 14 to 42% by weight from the viewpoint of interlayer adhesion and the like.

As described above, R in the benzoic acid ester compound (solvent component) represented by the general formula (1) is an alkyl group having 6 to 10 carbon atoms, preferably an alkyl group having 8 to 10 carbon atoms. Further, the above-mentioned alkyl group is intended to include both linear and branched ones. Even when R in the general formula (1) is an alkyl group, if the number of carbon atoms is less than the specified range of the present invention, the suppression of VOC becomes insufficient, and conversely, the specified range of the present invention. If it exceeds, the weldability (solubility) of the inner layer 1 and the outer layer 2 becomes insufficient.

As the polymer of the rubber composition constituting the inner layer 1 and the outer layer 2, a nitrile rubber or a halogen rubber is used, and these are used alone or in combination of two or more. The nitrile rubber preferably includes NBR such as acrylonitrile butadiene rubber (NBR), hydrogenated acrylonitrile butadiene rubber (H-NBR), and a blend polymer of acrylonitrile butadiene rubber and polyvinyl chloride (NBR / PVC). The rubber system is used alone or in combination of two or more. Further, as the halogen-based rubber, preferably, chloroprene rubber (CR), hydrin rubber (CO, ECO, GECO), chlorosulfonated polyethylene (CSM), chlorinated polyethylene (CM) and the like are used alone or in combination of two or more. It is also used.

As the polymer of the rubber composition constituting the inner layer 1, a polymer containing 60% by weight or more of nitrile rubber is preferably used from the viewpoint of oil resistance, sealing property and the like. More preferably, a polymer in which 80 to 100% by weight of the polymer is nitrile rubber is used. The amount of bound nitrile in the polymer of the rubber composition constituting the inner layer 1 is preferably 14 to 42% by weight from the viewpoint of interlayer adhesion and the like. Further, the vulcanizing agent in the rubber composition constituting the inner layer 1 is a sulfur compound, and the content of the sulfur compound is 0.2 to 5.0 parts by weight with respect to 100 parts by weight of the polymer. , Preferred from the viewpoint of interlayer adhesion.

When a halogen-based rubber is used as the polymer of the rubber composition constituting the inner layer 1, the amount of halogen in the polymer is preferably 25 to 42% by weight from the viewpoint of interlayer adhesion and the like.

Further, the polymer of the rubber composition constituting the inner layer 1 may be used in combination with a nitrile rubber or a halogen rubber, and if necessary, polyvinyl chloride (PVC), ethylene propylene diene rubber (EPDM), acrylic rubber ( AEM) and the like can also be contained.

As the polymer of the rubber composition constituting the outer layer 2, a polymer containing 60% by weight or more of halogen-based rubber is preferably used from the viewpoint of ozone resistance, weather resistance and the like. More preferably, a halogen-based rubber is used in which 80 to 100% by weight of the polymer is halogen-based. The amount of halogen in the polymer of the rubber composition constituting the outer layer 2 is preferably 25 to 42% by weight from the viewpoint of interlayer adhesion and the like.

Further, the polymer of the rubber composition constituting the outer layer 2 may be used in combination with a nitrile rubber or a halogen rubber, and if necessary, polyethylene (PE), ethylene propylene diene rubber (EPDM), styrene butadiene rubber (SBR). ) Etc. can also be contained.

In the welded surface of the inner layer 1 and the outer layer 2, the rubber of the welded surface is collected as a sample, the sample is extracted with acetone, and quantitative analysis is performed by gas chromatography, whereby the general formula (1) is shown. It can be confirmed whether or not the benzoic acid ester compound is used. Further, the benzoic acid ester compound in acetone can be quantified by gas chromatography analysis of a known concentration of benzoic acid ester in advance to prepare a calibration curve.

Further, the hose shown in FIG. 2 is another example of the hose of the present invention, and a reinforcing thread layer 3 is provided between the inner layer 1 and the outer layer 2 provided on the outer periphery of the inner layer 1. Although not clearly shown in FIG. 2, the layer between the inner layer 1 and the outer layer 2 is a welding surface formed by the solvent component represented by the general formula (1). That is, the outer peripheral surface of the inner layer 1 and the inner peripheral surface of the outer layer 2 are dissolved and welded by the solvent component through the stitches of the reinforcing yarn in the reinforcing yarn layer 3. Therefore, if the braid density of the reinforcing yarn in the reinforcing yarn layer 3 is too high, the welded surface cannot be formed.

As the material for forming the inner layer 1 and the outer layer 2 in the hose shown in FIG. 2, the solvent component used for adhesion between the layers, and the like, those according to the hose shown in FIG. 1 are used.

Further, the reinforcing yarn layer 3 is formed by spirally braiding reinforcing yarns such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), aramid, polyamide (nylon), polyvinyl alcohol (vinylon), rayon, and metal wire. It can be formed by braiding with a knit braid, a blade braid, or the like. The braid density of the reinforcing yarn in the reinforcing yarn layer 3 is preferably in the range of 20 to 95%, more preferably in the range of 40 to 70%, from the viewpoint of interlayer adhesiveness (welded surface) and the like. is there. That is, if the braid density is too high, the welded surface will not be formed, and conversely, if the braid density is too low, the hose reinforcement performance such as pressure resistance cannot be obtained.

Here, the hose of the present invention shown in FIGS. 1 and 2 can be manufactured, for example, as follows. That is, first, a rubber composition for forming an inner layer (at least one of a nitrile-based rubber composition and a halogen-based rubber composition) kneaded with a mixing roll or the like is extruded into a tubular shape. At this time, a mandrel may be used. Next, if necessary, the reinforcing yarns are braided at a predetermined braid density on the outer peripheral surface of the rubber composition layer for forming the inner layer obtained by the extrusion molding to form the reinforcing yarn layer 3. In the case where the mandrel is not used, when the reinforcing yarn is braided, if the rubber composition layer for forming the inner layer is subjected to internal pressure by air, the braiding becomes easier. Subsequently, the benzoic acid ester compound (solvent) represented by the general formula (1) is applied to the outer peripheral surface of the rubber composition layer for forming the inner layer (when the reinforcing thread layer 3 is formed, the outer peripheral surface of the reinforcing thread layer 3). A liquid agent having a component) of 95 to 100% by weight is applied. Then, a rubber composition for forming an outer layer (at least one of a nitrile rubber composition and a halogen rubber composition) kneaded with a mixing roll or the like is extruded into a tubular shape on the coated surface of the liquid agent. Then, the target hose can be produced by steam vulcanizing the unvulcanized laminated hose thus obtained in a steam vulcanizing can at 140 to 170 ° C. for 10 to 60 minutes. ..

When the hose of the present invention is manufactured according to the above manufacturing method, the generation of VOC in the manufacturing process can be suppressed, which can greatly contribute to the improvement of the working environment and the local environment. Further, by the above manufacturing method, the hose of the present invention having excellent performance as described above can be manufactured more efficiently.

When the liquid agent used in the production method contains only the solvent component represented by the general formula (1), it becomes more excellent in terms of workability and the like.

Further, when the liquid agent used in the production method is an adhesive containing the solvent component represented by the general formula (1) and a nitrile rubber, the interlayer adhesiveness between the inner layer 1 and the outer layer 2 is improved. Become.

The reinforcing thread layer 3 is not formed after the reinforcing thread is subjected to an adhesive dip treatment. Therefore, the manufacturing cost can be reduced and the complexity in the manufacturing process can be eliminated as compared with the case where the reinforcing thread layer 3 is formed after dipping the reinforcing thread with the adhesive.

In the hose of the present invention thus obtained, the hose inner diameter is preferably in the range of 2.5 to 90 mm. Further, in the hose of the present invention, from the viewpoint of hose performance, the thickness of the inner layer 1 is preferably in the range of 1.0 to 5.0 mm, more preferably 1.5 to 3.0 mm. Further, in the hose of the present invention, the thickness of the outer layer 2 is preferably in the range of 0.5 to 5.0 mm, more preferably 0.8 to 3.0 mm from the viewpoint of the hose performance.

Further, in the hose of the present invention thus obtained, for example, an innermost layer made of fluororubber, fluororesin, polyamide resin or the like may be further provided on the inner peripheral surface of the inner layer 1 as required. An outermost layer made of EPDM, polyurethane, or the like may be further provided on the outer periphery of the outer layer 2.

The hose of the present invention is suitably used as a fuel hose, an oil hose, an air hose, etc. for automobiles. Further, the hose can be applied not only to automobiles but also to other transportation machines (airplanes, forklifts, excavators, industrial transportation vehicles such as cranes, railway vehicles, etc.).

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

First, prior to Examples and Comparative Examples, the following polymers (NBR, NBR / PVC, H-NBR, BR) were prepared as nitrile rubbers.
-NBR-1: Nipole DN401 (bound nitrile amount = 18% by weight), manufactured by Nippon Zeon Co., Ltd.-NBR-2: Nipol DN302 (bound nitrile amount = 27.5% by weight), manufactured by Nippon Zeon Co., Ltd.-NBR-3: Nipol DN202 (Amount of bound nitrile = 31% by weight), manufactured by Nippon Zeon, NBR-4: Nipole DN101 (Amount of bound nitrile = 42% by weight), manufactured by Nippon Zeon, NBR, PVC: Nipol 1203W (Amount of bound nitrile = 50% by weight) %, PVC amount = 30% by weight, chlorine amount = 17% by weight), manufactured by Nippon Zeon, H-NBR: ZETPOL 2020 (bonded nitrile amount = 35% by weight), manufactured by Nippon Zeon, BR: Ubepol BR-150 , Made by Ube Kosansha

Further, as the halogen-based rubber, the following polymers (polychloroprene, CSM polymer, chlorinated polyethylene, epichlorohydrin polymer) were prepared.
-Polychloroprene: Denca chloroprene M-40, manufactured by DENKA-CSM polymer: TOSO CSM TS-430 (chlorine content = 35% by weight), manufactured by Tosoh Corporation-Chlorinated polyethylene-1: Eraslen 301 (chlorine content = 31% by weight) ), Showa Denko Co., Ltd. chlorinated polyethylene-2: Eraslen 351 (chlorine amount = 35% by weight), Showa Denko Co., Ltd. chlorinated polyethylene-3: Eraslen 402 (chlorine amount = 39% by weight), Showa Denko Co., Ltd. -Epichlorohydrin polymer-1 to -3: Epichlorohydrin polymer with composition and chlorine content shown in Table 1 below

Further, each material of the compounding formulations A to E to be blended in the ratio shown in Tables 2 to 6 below was prepared with respect to 100 parts by weight of the polymer such as nitrile rubber and halogen rubber.

Further, as the interlayer adhesive, the compounds (solvents) shown below and the adhesive prepared as follows were prepared. In addition, "(C *)" shown in the following compound indicates that the number of carbon atoms of the ester-bonded alkyl group is *.

[Benzoic acid ester (C4)]
Butyl benzoate (manufactured by Wako Pure Chemical Industries, Ltd.)

[Benzoic acid ester (C6)]
Hexil benzoate (manufactured by Wako Pure Chemical Industries, Ltd.)

[Benzoic acid ester (C8)]
Benzoic acid ester (Adecasizer A-6508, manufactured by ADEKA Corporation) in which R is an alkyl group having 8 carbon atoms represented by the following general formula (1).

[Benzoic acid ester (C10)]
Benzoic acid ester (Adecasizer A-6510, manufactured by ADEKA Corporation) in which R is an alkyl group having 10 carbon atoms represented by the following general formula (1).

[Benzoic acid ester (C12)]
Dodecyl benzoate

[Phthalate (C4)]
Dibutyl phthalate (DBP, manufactured by Daihachi Chemical Co., Ltd.)

[Phthalate (C8)]
Bis phthalate (2-ethylhexyl) (DEHP, manufactured by Daihachi Chemical Co., Ltd.)

[Isoparaffin solvent]
IP Solvent 1620 (manufactured by Idemitsu Kosan Co., Ltd.)

〔toluene〕
toluene

[Adhesive (C8)]
Each material shown in Table 7 below was blended in the ratio shown in the same table and kneaded with a mixing roll to prepare a rubber composition. An adhesive was prepared by adding 95% by weight of the above benzoic acid ester (C8) to 5% by weight of the rubber composition thus obtained to dissolve the rubber composition.

[Example 1]
First, NBR-1 prepared as a polymer of the inner layer material and another inner layer material were mixed according to the compounding formula A and then kneaded with a mixing roll to prepare a rubber composition for forming an inner layer. Further, polychloroprene prepared as a polymer of the outer layer material and another outer layer material were blended according to Formulation B and then kneaded with a mixing roll to prepare a rubber composition for forming an outer layer. Then, the rubber composition for forming the inner layer was hollow-extruded into a tubular shape by an extruder. Internal pressure is applied to the inside (hollow portion) of the hose thus obtained by air, and a single-twisted polyester reinforcing yarn having a thickness of 1500 denier is placed on the outer peripheral surface of the hose with a braid density of 60. %, Braided by the blade method. Further, the adhesive-1 prepared above as an interlayer adhesive is applied onto the reinforcing yarn braided in this manner to a thickness of 50 μm, and then the rubber composition for forming an outer layer is applied onto the coated surface. It was extruded with an extruder. The unvulcanized laminated hose thus obtained was directly steam vulcanized in a steam vulcanization can at 150 ° C./30 minutes. As a result, a hose having an inner diameter of 9.0 mm, an inner layer thickness of 2.0 mm, and an outer layer thickness of 1.5 mm was obtained.

[Examples 2 to 20, Comparative Examples 1 to 9]
As the rubber composition for forming the inner layer and the rubber composition for forming the outer layer, those having the compounding formulations shown in Tables 8 to 10 described later were prepared and used according to Example 1. Further, as the interlayer adhesive, those shown in Tables 8 to 10 described later were used. A target hose was produced in the same manner as in Example 1 except for the above. In the table, "*" indicates the interlayer adhesive used, and those without "*" indicate that the interlayer adhesive is not used.

The characteristics of the hoses of Examples and Comparative Examples thus obtained were evaluated according to the following criteria. The results are also shown in Tables 8 to 10 below.

≪Adhesiveness≫
A knife was used to make a cut in the longitudinal direction of the hose to reach the reinforcing thread layer on the outer peripheral surface of the hose cut to a length of 25 mm. Then, from the cut, the "inner layer + reinforcing thread layer" and the outer layer are partially peeled off, and the partially peeled outer layer is sandwiched between the chucks of the tensile tester, and the peeling test is performed according to JIS K6330. Was done. Then, the peel strength (N / 25 mm) at that time was measured, and the state of the peeled surface was visually observed and evaluated according to the following criteria.
<R: Out of rubber R: Rubber destruction BR: Partial rubber destruction K: Interface peeling

≪Low VOC≫
Those having no offensive odor due to volatile organic compounds (VOC) during hose production were evaluated as ◯, and those having strong offensive odor due to VOC during hose production were evaluated as x.

From the results in the above table, it was confirmed that the hoses of the examples all had high peel strength between layers and achieved low VOC during hose production. Among them, in the hoses of Examples 15 to 20, although only the solvent was used as the interlayer adhesive, the outer peripheral surface of the inner layer and the inner peripheral surface of the outer layer were well welded, and high peel strength was obtained. ..

On the other hand, the hose of Comparative Example 1 did not use an interlayer adhesive, and interfacial peeling was observed. In the hose of Comparative Example 2, the benzoic acid ester used as an interlayer adhesive made good welding on the outer peripheral surface of the inner layer and the inner peripheral surface of the outer layer, and good peel strength was obtained. However, the alkyl group in the benzoic acid ester was used. Since it was too small (too few carbon atoms), a strong offensive odor due to VOC was generated during hose production. In the hose of Comparative Example 3, since the alkyl group in the benzoic acid ester used as the interlayer adhesive is too large (the number of carbon atoms is too large), the welding of the outer peripheral surface of the inner layer and the inner peripheral surface of the outer layer is not good, and the peel strength It was also weak, and interfacial peeling was also observed. The hoses of Comparative Examples 4 to 6 use a conventional solvent known to generate less VOC as an interlayer adhesive, and the outer peripheral surface of the inner layer and the inner peripheral surface of the outer layer are not well welded and peeled off. The strength was also weak, and interfacial peeling was also observed. In the hose of Comparative Example 7, the outer peripheral surface of the inner layer and the inner peripheral surface of the outer layer were well welded by toluene, but a strong offensive odor due to VOC generated from toluene was generated during hose production. In the hoses of Comparative Examples 8 and 9, the inner layer rubber and the outer layer rubber were halogen-based rubbers of the same type, but no interlayer adhesive was used, and interfacial peeling was observed.

The types of benzoic acid esters used as interlayer adhesives could be confirmed by analyzing the hoses of Examples and Comparative Examples according to the following analysis methods.

≪Analysis method of benzoic acid ester≫
About 1 g of rubber samples are collected from the inner layer rubber and the outer layer rubber near the reinforcing thread layer of the hose, cut into a size of about 1 mm square, and then the cut rubber is soxhlet-extracted with acetone for 16 hours. Then, the benzoic acid ester in the component extracted in acetone is quantitatively analyzed by gas chromatography.

The hose of the present invention is suitably used as a fuel hose, an oil hose, an air hose, etc. for automobiles. Further, the hose can be applied not only to automobiles but also to other transportation machines (airplanes, forklifts, excavators, industrial transportation vehicles such as cranes, railway vehicles, etc.).

1 inner layer 2 outer layer

Claims (7)

A tubular inner layer composed of at least one of the nitrile rubber composition and the halogen rubber composition, and an outer layer composed of at least one of the nitrile rubber composition and the halogen rubber composition provided on the outer periphery of the inner layer are provided. The hose is characterized in that the layer between the inner layer and the outer layer is a welded surface with a liquid agent having a solvent component represented by the following general formula (1) of 95 to 100% by weight .

The hose according to claim 1, wherein an adhesive layer composed of an adhesive containing the solvent component represented by the general formula (1) and a nitrile rubber is provided between the inner layer and the outer layer. The hose according to claim 1 or 2, wherein the polymer of the rubber composition constituting the inner layer contains 60% by weight or more of nitrile rubber. The hose according to any one of claims 1 to 3, wherein the polymer of the rubber composition constituting the outer layer contains 60% by weight or more of halogen-based rubber. The method for producing a hose according to any one of claims 1 to 4, wherein a rubber composition for forming an inner layer, which is at least one of a nitrile rubber composition and a halogen rubber composition, is extruded into a tubular shape. A step of applying a liquid agent having a solvent component represented by the following general formula (1) of 95 to 100% by weight on the outer peripheral surface of the rubber composition layer for forming an inner layer obtained by the above extrusion molding, and the above liquid agent A step of extruding a tubular rubber composition for forming an outer layer, which is at least one of a nitrile rubber composition and a halogen-based rubber composition, onto the outer peripheral surface of the coated rubber composition layer for forming an inner layer, and the above-mentioned extrusion molding. A method for manufacturing a hose, which comprises a step of heating and sulphurizing a rubber composition layer for forming an inner layer and a rubber composition layer for forming an outer layer.

The method for manufacturing a hose according to claim 5, wherein the liquid agent comprises only the solvent component represented by the general formula (1). The method for manufacturing a hose according to claim 5, wherein the liquid agent is an adhesive containing the solvent component represented by the general formula (1) and a nitrile rubber.

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