JP5641515B2 - Heat resistant hose for automobile - Google Patents

Description

The present invention relates to a heat-resistant hose for automobiles used as an air hose, fuel hose, radiator hose, etc. for automobiles , and particularly relates to a heat-resistant hose for automobiles suitable for diesel hoses.

  In recent years, exhaust gas regulations for diesel vehicles have been strengthened, and the introduction of a new engine system (common rail injection system), DPF system, and turbo system to reduce PM and NOx in exhaust gas has been in full swing. Accordingly, the performance requirements for diesel hoses (fuel hose, air hose, DPF sensor hose, etc. for diesel vehicles) are becoming stricter. In other words, the DPF system and turbo system tend to be heated to increase the combustion efficiency for the purpose of reducing exhaust gas such as PM and NOx, so the diesel hose has higher heat resistance, acid resistance and difficulty than before. Flammability and further low temperature properties (particularly low temperature compression set) are required.

  Conventionally, a laminated hose in which the inner layer is made of fluoro rubber (FKM) and the outermost layer is made of highly heat-resistant acrylic rubber has been used for the above applications (see, for example, Patent Document 1). .

JP 2007-230225 A

  In order to impart flame retardancy, the outermost layer of the hose used for the above applications is usually blended with a flame retardant such as aluminum hydroxide or a bromine-based compound.

  However, in order to achieve incombustibility of the hose with aluminum hydroxide, it is necessary to contain a large amount of aluminum hydroxide in the outermost layer as in the hose disclosed in Patent Document 1. In Patent Document 1, the outermost layer is not vulcanized by peroxide vulcanization (vulcanization with a peroxide vulcanizing agent). For example, the outermost layer is vulcanized by peroxide vulcanization. Since there is no allowance for rubber physical properties, the breaking strength (tensile strength and breaking elongation) of the outermost layer is reduced by blending a large amount of aluminum hydroxide.

  On the other hand, the use of bromine-based compounds that have been conventionally used as flame retardants is regarded as a problem from the viewpoint of environmental pollution.

This invention is made | formed in view of such a situation, The objective is to provide the heat resistant hose for motor vehicles excellent in heat resistance and a flame retardance, maintaining a fracture strength.

In order to achieve the above object, a heat-resistant hose for automobiles of the present invention is a hose comprising a tubular inner layer and an outermost layer provided on the outer periphery directly or via another layer, the outermost layer being The rubber composition is composed of a rubber composition containing the following (A) as a main component and the following (B) to (D) components.
(A) Ethylene acrylic rubber.
(B) At least one of chlorinated polyethylene (CPE) and chlorosulfonated polyethylene (CSM).
(C) Antimony trioxide.
(D) Peroxide vulcanizing agent.

The present inventor has earnestly focused on the outermost layer forming material in order to obtain a heat resistant hose for automobiles (hereinafter referred to as “heat resistant hose”) having excellent heat resistance and flame retardancy while maintaining the breaking strength. Repeated research. In the course of the research, ethylene acrylic rubber is used as the polymer for forming the outermost layer, and antimony trioxide is added as a flame retardant instead of the conventional aluminum hydroxide, which provides a flame retardant effect with a small amount of addition. It was investigated. However, in order to exhibit a flame retardant effect by antimony trioxide, a halogen gas is required, so that even if it is added to ethylene acrylic rubber which is a non-halogen polymer, a sufficient flame retardant effect cannot be obtained. Therefore, the present inventor has conceived and implemented a predetermined amount of chlorinated polyethylene or chlorosulfonated polyethylene (component (B)) together with ethylene acrylic rubber as a polymer for forming the outermost layer. As a result, it has been found that halogen gas can be supplied from chlorinated polyethylene or chlorosulfonated polyethylene [component (B)], and thereby the flame retarding effect of antimony trioxide can be sufficiently exhibited. And it became clear that the following effects are acquired by the said structure. That, chlorinated polyethylene or chlorosulfonated polyethylene, as well as ethylene acrylic rubber, since having an ethylene chain in its molecular chain, easily mixed uniformly with high affinity and ethylene acrylic rubber, as with further ethylene acrylic rubber Since peroxide vulcanization is possible, it has been found that the co-crosslinking achieves a flame retardant effect without reducing physical properties such as breaking strength.

The outermost layer of the heat-resistant hose of the present invention contains at least one of chlorinated polyethylene (CPE) and chlorosulfonated polyethylene (CSM) [component (B)] and antimony trioxide [component (C)]. It consists of an oxide vulcanized ethylene acrylic rubber. Therefore, it is excellent in heat resistance and flame retardancy while maintaining the breaking strength. From this, it is suitable for a high temperature use environment, and can exhibit particularly excellent performance as a diesel hose (a fuel hose, an air hose, a DPF sensor hose, a radiator hose, a vacuum brake hose, etc. for diesel vehicles).

It is a schematic diagram which shows an example of the heat-resistant hose of this invention.

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

As shown in FIG. 1, the heat resistant hose of the present invention includes, for example, an intermediate layer 2 formed on the outer peripheral surface of a tubular inner layer 1 and an outermost layer 3 formed on the outer peripheral surface thereof. In the heat-resistant hose of the present invention, the outermost layer 3 is composed mainly of ethylene acrylic rubber (component (A)) and at least one of chlorinated polyethylene (CPE) and chlorosulfonated polyethylene (CSM) [(B) Component], antimony trioxide [(C) component], and a peroxide vulcanizing agent [(D) component]. Here, the “main component” means a substance that greatly affects the properties of the composition.

  As the material for forming the inner layer 1, for example, acrylonitrile-butadiene rubber (NBR), blend rubber of NBR and polyvinyl chloride (NBR-PVC), acrylic rubber, ethylene acrylic rubber, fluoro rubber, fluororesin, or the like is used. These may be used alone or in combination of two or more. Of these, fluororubber and fluororesin are preferably used because of excellent heat resistance and low permeability. In addition, the material for the inner layer 1 includes a filler (carbon black, etc.), a vulcanizing agent, an acid acceptor, a vulcanization accelerator, an anti-aging agent, a plasticizer, a vulcanization retarder, and a processing aid as necessary. A flame retardant, a scorch inhibitor, a colorant and the like may be blended.

  Examples of the material for forming the intermediate layer 2 laminated on the outer periphery of the inner layer 1 include epichlorohydrin polymer rubber (CO), epichlorohydrin-ethylene oxide copolymer rubber (ECO), epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer rubber. A hydrin rubber such as (GECO), acrylic rubber (ACM), ethylene vinyl acetate copolymer (EVM) or the like is used, and these are used alone or in combination of two or more. The material for the intermediate layer 2 includes, if necessary, fillers (carbon black, silica, etc.), vulcanizing agents, acid acceptors, vulcanization accelerators, plasticizers, anti-aging agents, vulcanization retarders, processing aids. You may mix | blend an agent, a flame retardant, a scorch inhibitor, a coloring agent, etc. In the present invention, the intermediate layer 2 is a layer provided as necessary. For example, when the inner layer 1 is made of a high-cost material such as fluororubber or fluororesin, the intermediate layer 2 is provided. As a result, the inner layer 1 can be made thinner, and the material cost can be reduced.

And as mentioned above, as a forming material of the outermost layer 3 laminated on the outer periphery of the intermediate layer 2, the main component is ethylene acrylic rubber (component (A)), chlorinated polyethylene (CPE) and A rubber composition containing at least one [component (B)] of chlorosulfonated polyethylene (CSM), antimony trioxide [component (C)], and peroxide vulcanizing agent [component (D)] is used.

The monomer used in the ethylene acrylic rubber of the component (A), other ethylene, for example, A acrylic acid ester, vinyl acetate Ru mentioned. Examples of the acrylate ester include alkyl acrylate esters such as methyl acrylate, ethyl acrylate and n-butyl acrylate, and alkoxy alkoxy acrylate esters such as methoxyethyl acrylate. Moreover, you may copolymerize 0-5 weight% of bridge | crosslinking site | part containing monomers as needed. 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, glycidyl methacrylate, maleic acid monobutyl ester and the like are preferable.

In addition, as a commercial item of the said ethylene acrylic rubber, VAMAC etc. by DuPont can be used as a suitable thing, for example.

  Examples of the chlorinated polyethylene (CPE) and chlorosulfonated polyethylene (CSM) [(B) component] used together with the component (A) include a weight average molecular weight (Mw) of 10,000 to 700,000. Those in which 20 to 50% of the molecular chains are chlorinated are preferably used from the viewpoint of cold resistance and heat resistance. In addition, since the component (B) is “at least one of chlorinated polyethylene (CPE) and chlorosulfonated polyethylene (CSM)”, CPE and CSM can be blended independently, respectively. And CSM may be used in combination.

The blending ratio of the component (B) is preferably set in the range of 10 to 50 parts with respect to 100 parts by weight (hereinafter abbreviated as “part”) of the ethylene acrylic rubber of the component (A). That is, when the blending ratio of chlorinated polyethylene is less than the above range, the supply of halogen gas by chlorinated polyethylene or chlorosulfonated polyethylene becomes insufficient, and the flame retardant effect by antimony trioxide [(C) component] is sufficiently obtained. This is because it cannot be expressed, and conversely, if it exceeds the above range, low temperature properties (particularly low temperature compression set) and heat resistance tend to deteriorate.

  In addition, the polymer component [total of (A) and (B) component] of the rubber composition constituting the outermost layer 3 usually occupies 50% by weight or more of the entire rubber composition.

The blending ratio of antimony trioxide (Sb ₂ O ₃ ) (component (C)) used together with the components (A) and (B) is 0.5 to 100 parts per 100 parts of the ethylene acrylic rubber of the component (A). It is preferably set in the range of 20 parts, more preferably in the range of 3 to 15 parts. That is, if the blending ratio of antimony trioxide is less than the above range, the flame retardant effect cannot be sufficiently exhibited, and if it exceeds the above range, heat resistance tends to be deteriorated.

  Examples of the peroxide vulcanizing agent (component (D)) used together with the components (A) to (C) 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) cyclohexane Dodecane, 1,1-bis (t-butylperoxy) cyclohexane, 2,2-bis (t-butylperoxy) octane, n-butyl-4,4-bis (t-butylperoxy) butane, n- Peroxyketals such as butyl-4,4-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) hexane, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne-3 and other dialkyl peroxides, acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, Diacyl peroxides such as decanoyl peroxide, lauroyl peroxide, 3,5,5-trimethylhexanoyl peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, m-trioyl peroxide, t- Butyl peroxyacetate, t-butylperoxyisobutylene T-butylperoxy-2-ethylhexanoate, t-butylperoxylaurate, t-butylperoxybenzoate, di-t-butylperoxyisophthalate, 2,5-dimethyl-2,5- Peroxyesters such as di (benzoylperoxy) hexane, t-butylperoxymaleic acid, t-butylperoxyisopropyl carbonate, cumylperoxyoctate, t-butyl hydroperoxide, cumene hydroperoxide, diisopropyl Examples thereof include hydroperoxides such as benzene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, 1,1,3,3, -tetramethylbutyl peroxide. These may be used alone or in combination of two or more.

The blending ratio of the peroxide vulcanizing agent of the component (D) is preferably set in the range of 0.5 to 10 parts, more preferably 100 parts by weight of the ethylene acrylic rubber of the component (A). Is in the range of 1.5 to 5 parts. That is, if the proportion of the peroxide vulcanizing agent is less than the above range, crosslinking is insufficient and the strength of the hose becomes inferior. On the contrary, if it exceeds the above range, it becomes too hard. This is because the flexibility of the hose tends to be impaired.

  In addition to the components (A) to (D), a co-crosslinking agent may be appropriately blended in order to increase the crosslinking efficiency of the outermost layer 3 and improve the physical properties. Examples of such a co-crosslinking agent include polyfunctional monomers [triallyl isocyanurate (TAIC) and the like], maleimide compounds, quinone compounds, sulfur-containing compounds, and the like. These co-crosslinking agents may be used alone or in combination of two or more.

  In addition to the above components, the material for the outermost layer 3 includes, if necessary, a filler (carbon black or the like), an antioxidant, an acid acceptor, a vulcanization accelerator, a plasticizer, and a vulcanization retarder. , Processing aids, scorch inhibitors, colorants and the like may be blended.

  The heat-resistant hose of the present invention shown in FIG. 1 can be produced, for example, as follows. That is, first, the inner layer 1 material (composition) is prepared by blending the components of the inner layer 1 material in a predetermined ratio and kneading them using a kneader. In the same manner, the material for the intermediate layer 2 and the material for the outermost layer 3 are also prepared. Next, the material (composition) for each layer prepared above is coextruded into a tube shape using an extruder, and then heated under predetermined conditions (for example, 160 to 190 ° C. × 10 to 60 minutes). ) And vulcanize. In this way, a heat resistant hose as shown in FIG. 1 can be produced.

  In the heat resistant hose, a reinforcing yarn layer may be interposed between the inner layer 1 and the intermediate layer 2 or between the intermediate layer 2 and the outermost layer 3. When the reinforcing yarn layer is provided in this manner, the durability is further enhanced, so that excellent performance can be exhibited as a high-pressure hose application. For example, when a reinforcing yarn layer is provided between the intermediate layer 2 and the outermost layer 3, first, a material for each layer is prepared by the same method as described above, and the inner layer 1 and the intermediate layer 2 are formed into a tube shape. After co-extrusion molding, an adhesive is applied to the outer peripheral surface as necessary, and a reinforcing yarn layer is formed by winding a reinforcing yarn (polyester, vinylon, aramid, nylon, etc.) around a spiral or blade or knitting. . Next, an adhesive is applied to the outer peripheral surface of the reinforcing yarn layer as necessary, and the material for the outermost layer 3 is extruded. And the target heat-resistant hose is obtained by heating and vulcanizing this.

  In the heat-resistant hose of the present invention thus obtained, the thickness of the outermost layer 3 is preferably 0.2 to 20 mm, more preferably 0.2 from the viewpoint of hose durability such as flame retardancy. ~ 4mm. Moreover, in FIG. 1, it is preferable that the thickness of the inner layer 1 is 0.1-10 mm, More preferably, it is 0.1-1 mm. Moreover, it is preferable that the thickness of the intermediate | middle layer 2 is 0.2-20 mm, More preferably, it is 0.2-4 mm. The hose inner diameter is preferably in the range of 2 to 100 mm, particularly preferably in the range of 3 to 20 mm.

  The outermost layer of the heat resistant hose of the present invention is flame retardant and can be used for various hoses. For example, automotive air hoses (supercharger hoses, blowby gas hoses, emission control hoses, etc. ), Useful as a fuel hose, radiator hose and the like. In particular, it can exhibit excellent performance as a diesel hose (fuel hose, air hose, DPF sensor hose, radiator hose, vacuum brake hose, etc. for diesel vehicles).

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

  First, prior to the examples and comparative examples, the following materials were prepared as materials for forming the outermost hose layer.

[ Ethylene acrylic rubber (component A)]
VAMAC DP, manufactured by DuPont

[Chlorinated polyethylene (CPE) (component B)]
Eraslen, Showa Denko

[Chlorosulfonated polyethylene (CSM) (component B)]
TS-430, manufactured by Tosoh Corporation

[Antimony trioxide (C component)]
Fire cut AT3, Suzuhiro Chemical Co., Ltd.

[Aluminum hydroxide]
Heidilite, Showa Denko

[Filler]
Seast SO, manufactured by Tokai Carbon

[Peroxide vulcanizing agent (component D)]
Perhexa 25B-40, manufactured by NOF Corporation

[Co-crosslinking agent]
Triallyl isocyanurate (TAIC) (TAIC-M60, manufactured by Nippon Kasei Co., Ltd.)

[Examples 1-6, Comparative Examples 1-7]
The components shown in Table 1 and Table 2 below were blended in the proportions shown in the same table, and kneaded using a kneader to prepare a rubber composition for forming the hose outermost layer.

Next, a fluororubber composition prepared in advance for forming the inner layer and an acrylic rubber composition prepared in advance for forming the intermediate layer were prepared. And these are coextruded into a tube shape together with the rubber composition for forming the outermost layer prepared as described above, heated at 160 ° C. for 45 minutes, and steam vulcanized to form the inner layer (fluororubber layer). A heat-resistant hose was produced in which an intermediate layer (acrylic rubber layer) was formed on the outer periphery, and an outermost layer ( ethylene acrylic rubber layer) was formed on the outer periphery (see FIG. 1). The heat-resistant hose was prepared so that the inner layer had a thickness of 0.5 mm, the intermediate layer had a thickness of 1.5 mm, the outermost layer had a thickness of 1.5 mm, and the hose inner diameter was 4.5 mm.

  With respect to the heat-resistant hose thus obtained, each characteristic was evaluated according to the following criteria. The results are shown in Tables 1 and 2 below.

[Normal properties]
Using the rubber composition for forming the outermost layer of the hose, this was formed into a sheet having a thickness of 2 mm, and press molded at 200 ° C. for 5 minutes to prepare a sample sheet (120 mm × 120 mm × thickness 2 mm). Then, in place of the normal physical properties of the hose itself, this sample sheet was used to measure tensile strength (TS) and elongation at break (Eb) according to JIS K 6251. Further, the hardness (hardness) of the sample sheet was measured in accordance with JIS K 6253. In these measurements, TS was 10 MPa or more, Eb was 250% or more, and the hardness (hardness) was 70 to 80, and the others were evaluated as x.

〔Flame retardance〕
A sample was cut out from the outermost layer of the hose, a flame was applied to the center, and the time until the sample ignited (combustion start time) was measured. Further, after the ignition, the flame was removed, and the time until the sample was extinguished (extinguishing time) was measured. And in the flame retardancy evaluation of this invention, the said combustion start time was 30 second or more, and the said fire extinguishing time was less than 60 second evaluated as (circle), and the other thing was evaluated as x.

  From the result of the said table | surface, both the normal state physical property and the flame retardance were favorable for the hose of the Example.

  On the other hand, the flame retardant effect by the flame retardant was not obtained in Comparative Examples 1 and 2. Although the fire extinguishing time was short, the products of Comparative Examples 3 to 7 had a short fire extinguishing time due to the flame retardant effect of aluminum hydroxide, but there was almost no effect on the combustion start time. In addition, a decrease in normal physical properties due to a large amount of aluminum hydroxide was also observed.

1 Inner layer 2 Middle layer 3 Outermost layer

Claims (5)

A hose comprising a tubular inner layer and an outermost layer provided on the outer periphery directly or via another layer, wherein the outermost layer is composed of the following (A) as a main component and the following (B) to ( D) A heat-resistant hose for automobiles comprising a rubber composition containing a component.
(A) Ethylene acrylic rubber.
(B) At least one of chlorinated polyethylene (CPE) and chlorosulfonated polyethylene (CSM).
(C) Antimony trioxide.
(D) Peroxide vulcanizing agent.   The heat-resistant hose for automobiles according to claim 1, wherein the rubber composition forming the outermost layer further contains triallyl isocyanurate.   The heat resistance for automobiles according to claim 1 or 2, wherein the blending amount of the component (B) in the rubber composition forming the outermost layer is in the range of 10 to 50 parts by weight with respect to 100 parts by weight of the component (A). hose.   In the rubber composition forming the outermost layer, the amount of antimony trioxide as the component (C) is in the range of 0.5 to 20 parts by weight with respect to 100 parts by weight of the component (A). 4. The heat-resistant hose for automobiles according to any one of 3 above.   It is a hose for diesel, The heat-resistant hose for motor vehicles as described in any one of Claims 1-4.

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