JP2006247883A - Oil hose - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oil hose excellent in heat resistance, having strength with respect to caulking or the like and having high interlaminar strength and excellent durability. <P>SOLUTION: The oil hose comprises the innermost layer 1 formed using an acrylic rubber, the intermediate layer 2 formed on the outer periphery thereof, and the outer layer 3, which is formed using at least one of a chlorinated polyethylene rubber or an ethylene/propylene/diene rubber, provided on the outer periphery of the intermediate layer 2. The intermediate layer 2 is formed from a rubber composition containing an acrylic elastomer (A), a peroxide crosslinking agent (B), a polyfunctional monomer (C) and a thiourea derivative (D) as essential components. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an oil pipe such as an automatic transmission fluid (ATF), power steering oil, and engine oil in a vehicle such as an automobile, and an oil hose used for transporting the oil.

Conventionally, oil hoses used for oil piping such as ATF in automobiles and the like have been formed to have a multilayer structure by laminating a rubber layer and a reinforcing yarn layer, but in recent years, as a material for forming the rubber layer, The use of acrylic rubber (usually amine-crosslinked ACM) with excellent heat resistance and oil resistance is becoming mainstream. By the way, the oil hose to which high pressure is applied is usually caulked with a clamp or the like when attached (when connected to a sleeve made of metal or the like). However, in general, an acrylic rubber hose is not strong enough to withstand the above caulking, and has a problem in its use because it causes breakage of the clamp. Therefore, for example, chlorinated polyethylene rubber (CPE), ethylene-propylene-diene rubber (EPDM), ethylene-acrylic rubber is provided on the outer periphery of the inner tube rubber layer (inner layer) made of acrylic rubber (ACM) that comes into contact with fluid such as oil. An outer layer made of a high-strength rubber such as (AEM) is formed to improve the strength (for example, see Patent Document 1).
JP-A-6-300169

  However, if the layer structure is as described above, the cross-linking mechanism of the rubber material of both the inner layer made of ACM and the outer layer made of high-strength rubber such as CPE is different, and the cross-linking (amine cross-linking) of ACM is extremely Due to the slowness, the adhesion between the two layers becomes poor. Therefore, in the oil hose having such a layer structure, there is a possibility that a buckling phenomenon is observed by caulking or that an oil pool is generated at the interface between both layers due to long-term use. In addition, the heat resistance performance is insufficient in a hose having a single layer structure made of CPE.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an oil hose that has excellent heat resistance, has strength against caulking, and has high interlayer adhesion and excellent durability.

In order to achieve the above object, an oil hose of the present invention comprises an innermost layer formed using acrylic rubber, an intermediate layer formed on the outer periphery thereof, and a chlorinated polyethylene rubber or ethylene on the outer periphery of the intermediate layer. -An oil hose comprising an outer layer formed using at least one of propylene-diene rubber, wherein the intermediate layer is formed of a rubber composition having the following (A) to (D) as essential components: It takes the composition that it is.
(A) Acrylic elastomer.
(B) Peroxide crosslinking agent.
(C) Multifunctional monomer.
(D) A thiourea derivative.

  That is, the present inventors ensure excellent heat resistance by the innermost layer formed using, for example, acrylic rubber (ACM), and have high strength made of chlorinated polyethylene rubber (CPE) formed on the outer periphery thereof. With the rubber layer (outer layer), research was repeated to solve the problem of adhesiveness between the two layers of the laminated hose that eliminated the clamp breakage during caulking. In the course of the research, we recalled that an interlayer formed using an acrylic rubber composition containing a peroxide crosslinking agent, a polyfunctional monomer, and a thiourea derivative was provided between the two layers. . Thereby, the crosslinking rate of the intermediate layer approaches the crosslinking rate of the outer layer, the interlayer adhesion between the outer layer and the intermediate layer becomes good, and at the same time, the intermediate layer becomes an acrylic rubber layer like the innermost layer. Since the interlayer adhesion between the intermediate layer and the innermost layer is also good, the inventors have found that the intended purpose can be achieved and have reached the present invention.

  As described above, the oil hose of the present invention has a laminated structure of an ACM layer that is the innermost layer, an intermediate layer, and an outer layer formed by at least one of CPE or EPDM, It is formed of an acrylic rubber composition containing a specific component, that is, a peroxide crosslinking agent, a polyfunctional monomer, and a thiourea derivative. Therefore, the oil hose of the present invention has excellent heat resistance and strength against caulking, and since the interlayer adhesion is high, buckling phenomenon and oil accumulation at the interface between both layers do not occur, Excellent quality and reliability. Furthermore, since CPE and EPDM are inexpensive materials, cost reduction can be realized incidentally.

  In particular, the acrylic ester content in the acrylic elastomer that is the polymer component of the intermediate layer material is 70 to 100% by weight, the ethylene content is 0 to 10% by weight, and the vinyl acetate content is 0 to 0%. When it is 20% by weight, the balance of heat resistance, oil resistance and cold resistance is more excellent.

  When the polyfunctional monomer in the intermediate layer material is a polyfunctional (meth) acrylic acid ester, an interlayer between the intermediate layer and an outer layer (rubber layer formed by at least one of CPE or EPDM) Adhesion is higher.

  Further, when phenothiazine is contained in the intermediate layer material, the scorch property is improved, and the extrusion processability and the interlaminar adhesion property become more excellent.

  Further, when the outer layer (rubber layer formed of at least one of CPE or EPDM) is formed by peroxide crosslinking of a rubber composition as a forming material thereof, it has excellent heat resistance and good compression set characteristics. At the same time, interlayer adhesion is further enhanced.

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

For example, as shown in FIG. 1, the oil hose of the present invention is formed on the innermost layer 1 in contact with a fluid such as oil, the intermediate layer 2 formed on the outer peripheral surface thereof, and the outer peripheral surface of the intermediate layer 2. And an outer layer 3. The innermost layer 1 is formed using ACM, the intermediate layer 2 is formed of a rubber composition containing the following (A) to (D) as essential components, and the outer layer 3 is formed of CPE or EPDM. It is formed using at least one of these.
(A) Acrylic elastomer.
(B) Peroxide crosslinking agent.
(C) Multifunctional monomer.
(D) A thiourea derivative.

  The ACM that is the material for forming the innermost layer 1 is not particularly limited, and various acrylic rubbers mainly composed of an acrylic acid alkyl ester or an acrylic acid alkoxyalkyl ester can be used. The above “main component” preferably means that, for example, acrylic acid alkyl ester or acrylic acid alkoxyalkyl ester is 90% or more of the whole.

  Examples of the alkyl acrylate ester include methyl acrylate, ethyl acrylate, n-butyl acrylate, iso-butyl acrylate, tert-butyl acrylate, propyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, Examples thereof include alkyl acrylates having 1 to 20 carbon atoms in the alkyl group such as lauryl acrylate and stearyl acrylate. On the other hand, as the alkoxyalkyl acrylate, the alkoxy group or alkylene group such as methoxymethyl acrylate, methoxyethyl acrylate, ethoxyethyl acrylate, butoxyethyl acrylate, methoxyethoxyethyl acrylate or the like has 1 to 4 carbon atoms. An acrylic acid alkoxyalkyl ester is used.

  In addition to the above acrylic acid alkyl ester and acrylic acid alkoxyalkyl ester, those obtained by copolymerizing monomers such as ethylene and propylene can also be used for the ACM.

  Further, the ACM includes, as crosslinking active groups, epoxy group-containing monomers such as allyl glycidyl ether and glycidyl methacrylate, chlorine group-containing monomers such as 2-chloroethyl vinyl ether, vinyl chloroacetate, and chloroacetate, and ethylidene norbornene. It can also contain what copolymerized each component (monomer), such as unsaturated group containing monomers, such as carboxy group-containing monomers, such as acrylic acid.

  The ACM vulcanizing agent is not particularly limited, and examples thereof include 1-methylimidazole, 1,2-dimethylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole, and the like. Imidazole compounds, hexamethylenediamine, hexamethylenediamine carbamate, tetramethylenepentamine, hexamethylenediamine-cinnamaldehyde adduct, hexamethylenediamine dibenzoate salt, 4,4'-methylenedianiline, 4,4'-oxyphenyl Diphenylamine, m-phenylenediamine, p-phenylenediamine, 4,4'-methylenebis (o-chloroaniline) and the like are used. These may be used alone or in combination of two or more.

  As described above, the material of the intermediate layer 2 formed on the outer periphery of the innermost layer 1 includes an acrylic elastomer [component (A)], a peroxide crosslinking agent [component (B)], A functional monomer [component (C)] and a thiourea derivative [component (D)] are used as essential components.

  The acrylic elastomer of the component (A) is not particularly limited. For example, the acrylic ester content in the elastomer is 70 to 100% by weight, the ethylene content is 0 to 10% by weight, and acetic acid is used. It is preferable for the vinyl content to be 0 to 20% by weight because it is more excellent in heat resistance. Examples of the acrylate esters include alkoxy acrylates such as methyl acrylate, ethyl acrylate, n-butyl acrylate, and methoxyethyl acrylate. In the copolymerization, 0 to 5% by weight of the crosslinking site-containing monomer may be copolymerized. Examples of the monomer include monomers having an active halogen group, an epoxy group, a carboxyl group, a hydroxyl group, an amide group, a diene group, and the like. Of these, epoxy groups such as glycidyl methacrylate and carboxyl groups such as monobutyl maleate are preferable.

  In addition, as a commercial item of the above-mentioned acrylic elastomer, for example, Nipol AR manufactured by Nippon Zeon, Noxtite manufactured by Unimatec, Denka ER manufactured by Denki Kagaku Kogyo, VAMAC manufactured by DuPont, etc. Can be used.

  Examples of the peroxide crosslinking agent [component (B)] used together with the component (A) include 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1- Bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, 1,1-bis (t-butylperoxy) cyclododecane, 1,1 -Bis (t-butylperoxy) cyclohexane, 2,2-bis (t-butylperoxy) octane, n-butyl-4,4-bis (t-butylperoxy) butane, n-butyl-4,4 -Peroxyketals such as bis (t-butylperoxy) valerate, di-t-butyl peroxide, dicumyl peroxide, t-butylcumyl peroxide, α α'-bis (t-butylperoxy-m-isopropyl) benzene, α, α'-bis (t-butylperoxy) diisopropylbenzene, 2,5-dimethyl-2,5-di (t-butylperoxy) Dialkyl peroxides such as hexane, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne-3, acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, decanoyl peroxide, Diacyl peroxides such as lauroyl peroxide, 3,5,5-trimethylhexanoyl peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, m-trioyl peroxide, t-butyl peroxyacetate, t-butyl peroxyisobutyrate, t- Butyl peroxy-2-ethylhexanoate, t-butyl peroxylaurate, t-butyl peroxybenzoate, di-t-butyl peroxyisophthalate, 2,5-dimethyl-2,5-di (benzoylper) Peroxyesters such as oxy) hexane, t-butylperoxymaleic acid, t-butylperoxyisopropyl carbonate, cumylperoxyoctate, t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide , Hydroperoxides such as 2,5-dimethylhexane-2,5-dihydroperoxide, 1,1,3,3, -tetramethylbutyl peroxide, and the like. These may be used alone or in combination of two or more.

  The blending ratio of the component (B) is preferably set in the range of 0.1 to 10 parts with respect to 100 parts by weight of the acrylic elastomer of the component (A) (hereinafter abbreviated as “part”). More preferably, it is the range of 0.25-5 parts. That is, when the peroxide crosslinking agent [component (B)] is less than 0.1 part, crosslinking is insufficient and the strength becomes inferior. Conversely, when it exceeds 10 parts, It is because the tendency which becomes too hard and a softness | flexibility is impaired is seen.

  Examples of the polyfunctional monomer (component (C)) used together with the components (A) and (B) include triallyl cyanurate, triallyl isocyanurate, triallyl trimellitate, trimethylolpropane trimethacrylate, polyethylene. Examples include glycol diacrylate and polyethylene glycol dimethacrylate. These may be used alone or in combination of two or more. Among them, when the polyfunctional monomer is a polyfunctional (meth) acrylic acid ester such as trimethylolpropane trimethacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, etc., the intermediate layer 2 and the outer layer 3 This is preferable because the interlayer adhesion is higher.

  The blending ratio of the component (C) is preferably set in the range of 0.5 to 15 parts, more preferably in the range of 1 to 8 parts, with respect to 100 parts of the acrylic elastomer of the component (A). It is. That is, if the polyfunctional monomer (component (C)) is less than 0.5 part, crosslinking is insufficient and the strength becomes inferior. Conversely, if it exceeds 15 parts, it is hard. This is because there is a tendency that flexibility is lost.

  Examples of the thiourea derivative [(D) component] used together with the components (A) to (C) include thiourea, N, N′-diphenylthiourea, diethylthiourea, dibutylthiourea, trimethylthiourea, and diralylthiourea. , 2-mercaptobenzimidazole, 2-mercaptobenzimidazole zinc salt and the like. These may be used alone or in combination of two or more. Of these, trimethylthiourea is preferably used in the present invention.

  The blending ratio of the component (D) is preferably set in the range of 0.1 to 5 parts, more preferably 0.3 to 3 parts, relative to 100 parts of the acrylic elastomer of the component (A). Range. That is, if the thiourea derivative [component (D)] is less than 0.1 part, the heat resistance may be insufficient, and conversely if it exceeds 5 parts, bleeding occurs, resulting in product properties. This is because there is a risk of causing trouble.

  By the way, in the said intermediate | middle layer 2, in addition to each component of said (A)-(D) which is the essential component, if it contains a phenothiazine [(E) component] as needed, the peroxide bridge | crosslinking of acrylic rubber will be carried out. Since the scorch property resulting from (peroxide crosslinking) is improved, the extrusion processability and the interlaminar adhesion become more excellent, which is preferable.

  The blending ratio of the component (E) is preferably set in the range of 0.01 to 5 parts, more preferably 0.1 to 1 part, with respect to 100 parts of the acrylic elastomer of the component (A). Range. That is, when phenothiazine [(E) component] is contained within this range, the scorch improving effect can be obtained.

  In addition to the above-mentioned components, the intermediate layer 2 material may include a reinforcing material, a white filler, a plasticizer, a vulcanizing agent, a vulcanization accelerator, a processing aid, an antiaging agent, a flame retardant, and the like as necessary. Can be added.

  As described above, at least one of CPE and EPDM is used as the material for the outer layer 3 formed on the outer periphery of the intermediate layer 2. If necessary, a vulcanizing agent, a vulcanization accelerator, a processing aid, a reinforcing material, a white filler, a plasticizer, stearic acid, an acid acceptor, and the like may be appropriately added thereto. And when the said outer layer 3 is formed by the peroxide bridge | crosslinking (crosslinking by a peroxide crosslinking agent) of the rubber composition which is the formation material, while being excellent in heat resistance and compression set property, This is preferable because the interlayer adhesion is further enhanced in synchronization with the crosslinking mechanism of the rubber material of the intermediate layer 2.

  Here, the oil hose shown in FIG. 1 can be manufactured as follows, for example. That is, first, a material composition for the innermost layer 1 is prepared using ACM. Moreover, each component material of said (A)-(D) is prepared, and other component materials [(E) component material etc.] are also prepared as needed, These are kneading machines, such as a roll, a kneader, a Banbury mixer The above-mentioned material composition for the intermediate layer 2 is prepared by kneading using the above. Further, a material composition for the outer layer 3 is prepared using at least one of CPE and EPDM. Next, after extruding the material composition for the innermost layer 1 into a cylindrical shape, the material composition for the intermediate layer 2 is extruded on the outer peripheral surface thereof, and further, the material composition for the outer layer 3 is formed on the outer peripheral surface thereof. Is extruded. Then, by vulcanizing each of these layers, a target oil hose can be obtained without applying an adhesive between the layers.

  In the manufacturing process, the material composition for the intermediate layer 2 is dissolved in a solvent such as toluene and xylene (dissolved so that the rubber component is in the range of 5 to 10% by weight), and extruded into a cylindrical shape. Application to the outer peripheral surface of the molded material composition for the innermost layer 1, and extrusion molding of the material composition for the outer layer 3 on the outer peripheral surface, and vulcanization of each of these layers makes it possible to obtain a target oil hose. It can also be manufactured.

  Further, each layer of the oil hose may be formed by coextrusion molding.

  By the way, in this invention, as shown in FIG. 2, the reinforcement thread | yarn layer 4 may be formed between the layers, and you may make it comprise the target oil hose. That is, the inner layer and the outer layer are in contact with each other through the weave of the reinforcing yarn layer 4 (in FIG. 2, the intermediate layer 2 and the outer layer 3 are in contact with each other through the weave of the reinforcing yarn layer 4). This is because even with the configuration as shown in FIG. 2, strong adhesion between layers, which is one of the features of the present invention, can be obtained. When the reinforcing yarn layer 4 is interposed between the layers as described above, the durability is further enhanced, so that excellent performance as a high-pressure hose application can be exhibited.

  Examples of the reinforcing yarn forming the reinforcing yarn layer 4 include vinylon (polyvinyl alcohol) yarn, polyamide (nylon) yarn, aramid yarn, polyethylene terephthalate (PET) yarn and the like.

  The method for braiding the reinforcing yarn is not particularly limited, and examples thereof include spiral knitting, knitting knitting, and blade knitting.

  Note that the oil hose of the present invention is not limited to the configuration shown in FIGS. 1 and 2. For example, a reinforcing surface layer may be formed on the outer peripheral surface of the outer layer 3.

  In the oil hose thus obtained, the inner diameter of the hose is preferably in the range of 2 to 50 mm, particularly preferably in the range of 5 to 40 mm. The thickness of the innermost layer 1 is preferably in the range of 0.5 to 20 mm, particularly preferably in the range of 1 to 10 mm, and the thickness of the intermediate layer 2 is preferably in the range of 0.05 to 10 mm, particularly preferably. Is in the range of 0.1 to 5 mm, and the thickness of the outer layer 3 is preferably in the range of 0.5 to 20 mm, particularly preferably in the range of 1 to 10 mm.

  The oil hose as described above is suitably used for piping of oil such as ATF, PSF, and engine oil in a vehicle such as an automobile (including a tractor and a cultivator). Specifically, a torque converter hose, an engine oil cooler hose, a power steering oil hose, etc. are mentioned.

  Next, examples will be described together with comparative examples.

  First, prior to the examples and comparative examples, the following materials were prepared.

[Acrylic elastomer (i) (component A)]
Acrylic rubber (made by Denki Kagaku Kogyo Co., Ltd.) having an n-butyl acrylate content of 86% by weight, an ethylene content of 0.5% by weight and a vinyl acetate content of 13.5% by weight

[Acrylic elastomer (ii) (component A)]
Acrylic rubber (made by Denki Kagaku Kogyo Co., Ltd.) having an n-butyl acrylate content of 44.5% by weight, an ethylene content of 0.5% by weight and an ethyl acrylate content of 55% by weight.

[Peroxide crosslinking agent (component B)]
n-Butyl-4,4-bis (t-butylperoxy) valerate (Perhexa V, manufactured by NOF Corporation)

[Multifunctional monomer (component C)]
Trimethylolpropane trimethacrylate (High Cloth M, Seiko Chemical Co., Ltd.)

[Thiourea derivative (component D)]
Trimethylthiourea (Noxeller TMU, manufactured by Ouchi Shinsei Chemical)

[Phenothiazine (E component)]
Phenothiazine (Seiko Chemical Co., Ltd.)

〔stearic acid〕
LUNAC S-30, manufactured by Kao

[Liquid paraffin]
Cristor 70, manufactured by Esso

[MAF carbon black]
Seast 116, manufactured by Tokai Carbon

[Vulcanizing agent]
1,2-dimethylimidazole, manufactured by Shikoku Chemicals

[Anti-aging agent]
Nowguard 445, made by Uniroyal

[Examples 1-8, Comparative Examples 1-7]
The materials shown above were blended in the proportions shown in Tables 1 and 2 below, and these were kneaded using a 5 L kneader to prepare intermediate layer materials (acrylic rubber compositions) a to g.

  Further, as shown below, innermost layer material α and outer layer materials β and γ were prepared.

[Preparation of innermost layer material α (material composition for ACM layer)]
First, an acrylic polymer comprising 99% by weight of ethyl acrylate and 1% by weight of fumaric acid monoethyl ester was prepared. 100 parts of this acrylic polymer, 2 parts of stearic acid (Lunac S30, manufactured by Kao Corporation), and anti-aging Agent (Naugard 445, manufactured by Uniroyal), 66 parts of FEF carbon black (Seast SO, manufactured by Tokai Carbon), plasticizer (Adeka RS-735, manufactured by Asahi Denka Kogyo Co., Ltd.), 5 parts, and a diamine compound (Diak # 1, manufactured by DuPont) 0.5 part and 2 parts of a guanidine compound (Noxeller DT, manufactured by Ouchi Shinsei Kagaku Co., Ltd.) are mixed to obtain the innermost layer material α (ACM layer material composition). Prepared.

[Preparation of outer layer material β (CPE layer material composition)]
100 parts of CPE (Tyrin CM0136, manufactured by DuPont Dow Elastomer), 40 parts of FEF carbon black (manufactured by Seast SO, manufactured by Tokai Carbon Co., Ltd.), and plasticizer (TOTM, Adeka Sizer C-8, manufactured by Asahi Denka Kogyo Co., Ltd.) 15 Parts, 3 parts of PO (Perhexa 25B-40, manufactured by Nippon Oil & Fats Co., Ltd.), 2 parts of crosslinking aid (TAIC, manufactured by Nippon Kasei Co., Ltd.), and acid acceptor (MgO, Kyowa Mag # 150, manufactured by Kyowa Chemical Industry Co., Ltd.) The outer layer material β (CPE layer material composition) was prepared by mixing 10 parts.

[Preparation of outer layer material γ (EPDM layer material composition)]
100 parts of EPDM (Esprene 532, manufactured by Sumitomo Chemical Co., Ltd.), 1 part of stearic acid (Lunac S-30, manufactured by Kao Corporation), 5 parts of zinc oxide 2 types (manufactured by Mitsui Kinzoku Co., Ltd.), and softener (Diana Process PW380) 70 parts by Idemitsu Kosan Co., Ltd., 2 parts by anti-aging agent (Nonflex RD, Seiko Chemical Co., Ltd.), 3 parts by PO (Park Mill D-40, by Nippon Oil & Fats Co., Ltd.), and crosslinking aid (TAIC, Japan) 2 parts (made by Kasei Co., Ltd.) were mixed to prepare an outer layer material γ (EPDM layer material composition).

  Using the material of each layer prepared in advance as described above, it was coextruded on a mandrel so as to have a laminated structure of combinations shown in Tables 3 to 5 below, heated at 160 ° C. for 1 hour, An oil hose was produced by secondary vulcanization in an oven at 150 ° C. for 8 hours (see FIG. 1). The oil hose was prepared such that the innermost layer had a thickness of 3 mm, the intermediate layer had a thickness of 0.5 mm, the outer layer had a thickness of 2 mm, and the hose inner diameter was 12 mm. However, the hose of Comparative Example 7 was not provided with an intermediate layer, and had the two-layer structure using the acrylic rubber composition a as the innermost layer material.

  Using each oil hose (or hose forming material) thus obtained, various properties were measured and evaluated according to the following methods. These results are shown in Tables 3 to 5 below.

〔Heat-resistant〕
Each hose was heat-aged at 150 ° C. for 2000 hours, and then the rubber of the innermost layer of the hose was sliced and collected. The hose was pulled with a JIS No. 5 dumbbell, and the elongation (%) at this time was measured. The elongation (heat resistance) required for the present invention is 150% or more.

[Interlayer adhesion]
A test piece was cut out from each oil hose, and the adhesive strength between the test piece layers (the innermost layer / intermediate layer layer and the intermediate layer / outer layer layer) was measured. That is, the intermediate layer (thickness 1.5 mm, width 25.4 mm) of the test piece was peeled off at a rate of 50 mm per minute using a tensile tester (JIS B 7721), and the interlayer adhesion (N / Mm) was measured. The interlayer adhesion required for the present invention is 2.0 N / mm or more.

  From the above results, all the products of the examples obtained excellent results with respect to heat resistance and interlayer adhesion.

  On the other hand, it can be seen that Comparative Examples 1 and 4 are inferior in interlayer adhesion because the intermediate layer is not formed by peroxide crosslinking. In Comparative Examples 2 and 5, the intermediate layer is formed by peroxide crosslinking, but since no thiourea derivative is added, it is understood that the adhesiveness with the rubber layer to be laminated is inferior. In Comparative Examples 3 and 6, the intermediate layer is formed by peroxide crosslinking, but since the polyfunctional monomer is not added, it is understood that the adhesiveness to the rubber layer to be laminated is inferior. The product of Comparative Example 7 does not satisfy the heat resistance required for the present invention.

  By the way, regarding all the examples, when the reinforcing yarn layer was interposed between the layers (see FIG. 2), various performances similar to the above-mentioned all examples were confirmed, and the durability of the hose was further enhanced. For example, it has been recognized that it can exhibit excellent performance as a high-pressure hose application. When forming the reinforcing yarn layer as described above when using an oil hose, the inner layer material is first extruded into a cylindrical shape, and then the intermediate layer material is dissolved in toluene on the outer peripheral surface thereof. After coating the adhesive (rubber component 10% by weight) and braiding the reinforcing yarn into a blade shape from above, the outer layer material is extruded on the outer peripheral surface, and each of these layers is vulcanized By doing so, a hose was produced.

It is a block diagram which shows an example of the oil hose of this invention. It is a block diagram which shows the other example of the oil hose of this invention.

Explanation of symbols

1 innermost layer 2 middle layer 3 outer layer

Claims (5)

An innermost layer formed using acrylic rubber, an intermediate layer formed on the outer periphery thereof, and an outer layer formed using at least one of chlorinated polyethylene rubber or ethylene-propylene-diene rubber on the outer periphery of the intermediate layer. An oil hose provided, wherein the intermediate layer is formed of a rubber composition having the following (A) to (D) as essential components.
(A) Acrylic elastomer.
(B) Peroxide crosslinking agent.
(C) Multifunctional monomer.
(D) A thiourea derivative.   The acrylic ester content in the acrylic elastomer shown in (A) is 70 to 100% by weight, the ethylene content is 0 to 10% by weight, and the vinyl acetate content is 0 to 20% by weight. Item 1. An oil hose according to Item 1.   The oil hose according to claim 1 or 2, wherein the polyfunctional monomer shown in (C) is a polyfunctional (meth) acrylic ester. The oil hose according to any one of claims 1 to 3, wherein the intermediate layer is formed of a rubber composition containing the following component (E) together with the components (A) to (D).
(E) Phenothiazine.   The oil hose according to any one of claims 1 to 4, wherein the outer layer is formed by peroxide crosslinking of a rubber composition that is a forming material thereof.

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