JP2006272897A - Hose for fuel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hose for a fuel which is excellent in flame retardance and heat resistance and is also excellent in the interlayer adhesiveness between a polyamide resin layer and the outermost layer and also can be produced at a low cost. <P>SOLUTION: The hose for the fuel comprises a tubular inner layer 1, an intermediate layer 2 provided on its periphery, and the outermost layer 3 provided in contact with the periphery. The above intermediate layer 2 is a polyamide resin layer, and the above outermost layer 3 comprises the followings (A)-(D) as indispensable components, and is formed with a rubber composition consisting of the component (A) and the component (B) blended at the weight ratio of (A)/(B)=7/3-5/5. (A) Acrylic series rubber (ACM). (B) Fluororubber (FKM). (C) Peroxide cross linking agent. (D) Resorcinol series compound. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel hose used for transportation of fuel such as automobiles (gasoline, alcohol-mixed gasoline, diesel fuel, etc.).

  A fuel hose used in an automobile or the like is usually configured by laminating a plurality of layers formed of resin, rubber, reinforcing yarn, or the like. The fuel hose is often used in a high temperature environment. As a conventional laminated hose having such a specification, for example, the outermost layer is made of acrylic rubber having excellent heat resistance and relatively inexpensive. Some are formed (for example, refer to Patent Document 1).

On the other hand, on the outer peripheral surface of the hose, a protector layer (a rubber layer made of chloroprene rubber, chlorinated polyethylene rubber, ethylene-propylene-diene rubber, etc.) excellent in flame retardancy is provided. It has already been proposed (see, for example, Patent Document 2).
JP 2000-6317 A JP-A-6-300169

  However, when the hose outermost layer is an acrylic rubber layer as in Patent Document 1, the desired flame retardancy cannot be obtained although the heat resistance is excellent. Therefore, for example, a method of adding a flame retardant to the acrylic rubber and thereby increasing the flame retardancy of the outermost layer has been studied. However, in this case, there is a problem that the physical properties of the outermost acrylic rubber layer are significantly lowered.

  On the other hand, when a protector layer is provided as in Patent Document 2 to increase the flame retardance of the hose, there is a problem of cost increase such as material cost and processing cost associated with adding the mounting process of the protector layer. Arise.

  By the way, in such a multilayer fuel hose, a polyamide resin is generally used as the innermost layer material because it is excellent in fuel oil resistance and low temperature impact resistance. Further, when the reinforcing yarn layer is formed on the fuel hose, a polyamide resin reinforcing yarn may be used as the material thereof. However, acrylic rubber has low adhesion to polyamide resin. For example, when such a polyamide resin layer is provided on the inner peripheral surface of the outermost acrylic rubber layer described at the beginning, an adhesive is usually provided between the two layers. In the case of a polyamide resin reinforcing yarn layer, an operation such as raising the reinforcing yarn to increase the adhesion is required. Therefore, in such a case, there are problems such as high manufacturing costs.

  The present invention has been made in view of such circumstances, and provides a fuel hose that is excellent in flame retardancy and heat resistance, is excellent in interlayer adhesion between a polyamide resin layer and an outermost layer, and is low in cost. For that purpose.

In order to achieve the above object, the fuel hose of the present invention is a fuel hose having a plurality of constituent layers, and includes a polyamide resin layer as a constituent layer in contact with the inner peripheral surface of the outermost layer, The outermost layer has the following components (A) to (D) as essential components, and the components (A) and (B) are in a weight ratio of (A) / (B) = 7/3 to 5 The composition is formed by a rubber composition blended at a ratio of / 5.
(A) Acrylic rubber (ACM).
(B) Fluoro rubber (FKM).
(C) Peroxide crosslinking agent.
(D) Resorcinol compound.

  That is, the present inventors have intensively studied to solve the above problems. In the course of that research, we found that when FKM is blended with ACM, the halogen group of FKM contributes to improve flame retardancy. Based on various experiments, the blend rubber is applied to the material for the outermost layer of the fuel hose, and flame retardancy is improved without impairing various physical properties required for the outermost layer. The appropriate range of blend ratio was derived. Furthermore, when the rubber blended at such a specific ratio is peroxide-crosslinked (peroxide-crosslinked), the heat resistance is improved, and a specific adhesive agent component (resorcinol compound, etc.) is further added to the rubber. As a result of the kneading, it was found that excellent adhesion to the polyamide resin layer can be obtained, and the present invention has been achieved.

  The reason why excellent resilience with the polyamide resin layer can be obtained by kneading the resorcinol compound in the outermost layer material as described above is presumed as follows. That is, first, the resorcinol compound replaces a part of fluorine in the FKM molecule and binds to the FKM molecule. Next, the fluorine radicals generated thereby attack the polyamide bond (—CONH—) of the polyamide resin. It is considered that the hydroxyl group of the resorcinol compound bonded to the FKM molecule by the substitution is hydrogen-bonded at the attacked site, and as a result, the adhesion is enhanced.

When a melamine resin is used together with the resorcinol compound, the resorcinol compound mainly functions as an adhesive agent, and the melamine resin mainly functions as an adhesion aid. That is, it is considered that the above resorcinol compound is supplied with CH ₂ O from the melamine resin, and this is covalently bonded to the polyamide bond (—CONH—) of the polyamide resin, thereby improving the adhesive force. At the same time, it is presumed that the affinity (reactivity) with the active sites of rubbers such as FKM and ACM can be improved by the combined use of the resorcinol compound and the melamine resin.

  As described above, the outermost layer of the fuel hose of the present invention contains a resorcinol compound together with ACM, FKM, and a peroxide cross-linking agent, and the blend ratio of the ACM and FKM is set within a specific range. It is formed by the made material. Therefore, flame retardancy can be realized without impairing heat resistance and physical properties of the hose. Further, since the oil resistance of the acrylic rubber (ACM) is improved by blending with FKM, the outermost layer thereof is excellent in low fuel permeability as compared with the conventional outer layer made of acrylic rubber. Furthermore, the interlayer adhesion with the polyamide resin layer laminated on the inner peripheral surface of the outermost layer is also excellent. And the hose for fuel of this invention can implement | achieve cost reduction rather than a flame retardant protector use.

  In particular, when the melamine resin is contained in the outermost layer material together with the resorcinol compound, the interlayer adhesion becomes more excellent.

  Next, an embodiment of the present invention will be described.

  The fuel hose of the present invention is configured, for example, as shown in FIG. 1, in which an intermediate layer 2 is formed on the outer peripheral surface of the inner layer 1, and an outermost layer 3 is formed on the outer peripheral surface thereof. In the present invention, the outermost layer 3 comprises an acrylic rubber (ACM) (component A), a fluororubber (FKM) (component B), a peroxide crosslinking agent (component C), and a resorcinol compound. (D component) is an essential component, and the ACM and FKM are formed by a rubber composition blended at a specific ratio. And the intermediate | middle layer 2 which contact | connects the inner peripheral surface of the said outermost layer 3 is formed with the polyamide resin.

  The material for forming the inner layer 1 is not particularly limited as long as it has fuel oil resistance and the like. For example, polyamide resin, fluororesin, polyolefin resin (polypropylene resin, polyethylene resin, polybutene resin, polybutene resin) Methyl pentene resin, etc.), acrylic rubber (ACM), fluorine rubber (FKM), acrylonitrile-butadiene rubber (NBR), hydrogenated nitrile rubber (H-NBR), blend rubber of acrylonitrile-butadiene rubber and polyvinyl chloride ( NBR-PVC), hydrin rubber, polyester-based thermoplastic elastomer (TPEE), or the like is used. These may be used alone or in combination of two or more. In addition, carbon black, a lubricant (such as stearic acid), zinc oxide, a softening agent (such as process oil), a vulcanizing agent (such as sulfur), and a vulcanization accelerator may be included in the material for forming the inner layer 1 as necessary. Further, a vulcanization aid, an antiaging agent, etc. may be blended appropriately.

  Since the intermediate layer 2 formed on the outer peripheral surface of the inner layer 1 is provided in contact with the inner peripheral surface of the outermost layer 3 in FIG. 1, a polyamide resin is used as the forming material. The polyamide resin is not particularly limited to aliphatic, aromatic, etc., for example, lactam polymer, diamine and dicarboxylic acid condensate, amino acid polymer, and copolymers and blends thereof. Etc. Specifically, nylon 6, nylon 11, nylon 12, nylon 610, nylon 612, polyphthalamide, a copolymer of nylon 6 and nylon 66, or a blend of two or more of these, a viscous mineral (nanocomposite) Etc.) are preferably used.

  The intermediate layer 2 may be a reinforcing yarn layer 2 'formed by braiding polyamide resin reinforcing yarns as shown in FIG. 2, for example. In FIG. 2, 1 is an inner layer, 3 is an outermost layer, and the material of each layer is the same as that of the hose of FIG. In addition to the above-described reinforcing yarns made of the polyamide resin, polyethylene terephthalate (PET) yarn, vinylon yarn, aramid yarn, wire, and the like are preferably used as the reinforcing yarn.

  As described above, the material for forming the outermost layer 3 is acrylic rubber (ACM) (component A), fluororubber (FKM) (component B), and peroxide crosslinking agent (C Component) and a resorcinol-based compound (component D) as essential components, and a rubber composition in which ACM and FKM are blended at a specific ratio is used.

  The ACM (A component) which is a constituent material of the outermost layer 3 is not particularly limited as long as it can be peroxide vulcanized. In particular, peroxide added having an unsaturated bond in the molecule is added. Sulfurable acrylic rubber is preferred. Such an acrylic rubber can be obtained by combining the following (meth) acrylate monomer and a polyfunctional monomer, and copolymerizing by a known polymerization method.

  The (meth) acrylate monomer is preferably represented by the following general formula (α). Specific examples include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, and the like.

  Examples of the polyfunctional monomer include allyl (meth) acrylate, ethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, divinylbenzene, polyethylene Examples include glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, ethylidene norbornene, and dicyclopentadiene.

  If necessary, a part of the (meth) acrylate monomer may be replaced with an ethylenically unsaturated monomer (for example, acrylonitrile, styrene, vinyl acetate, vinyl chloride, etc.) for polymerization.

  The FKM (component B) used together with the ACM is not particularly limited as long as it can be peroxide vulcanized. For example, vinylidene fluoride-3 fluoroethylene copolymer, vinylidene fluoride-6 propylene copolymer, vinylidene fluoride-6 propylene-4 fluoroethylene copolymer, tetrafluoroethylene-propylene Examples thereof include a copolymer, a tetrafluoroethylene-perfluorovinyl ether copolymer, and a vinylidene fluoride-4 fluoroethylene-perfluoroalkyl vinyl ether copolymer. These may be used alone or in combination of two or more. Among these, vinylidene fluoride-6-propylene-tetrafluoroethylene copolymer is preferable because it is excellent in low fuel permeability and heat resistance.

  In the rubber composition for forming the outermost layer 3, the weight mixing ratio of the ACM (A component) and the FKM (B component) is preferably within the range of ACM / FKM = 7/3 to 5/5. That is, if the ACM ratio in the mixing ratio is less than 5 (the FKM ratio exceeds 5), the cost increases. Conversely, the ACM ratio in the mixing ratio exceeds 7 (FKM ratio). This is because the flame retardancy is inferior.

  Examples of the peroxide crosslinking agent (component C) used together with the ACM and FKM include 2,4-dichlorobenzoyl peroxide, benzoyl peroxide, 1,1-di-t-butylperoxy-3,3,5-trimethyl. Cyclohexane, 2,5-dimethyl-2,5-dibenzoylperoxyhexane, n-butyl-4,4'-di-t-butylperoxyvalerate, dicumyl peroxide, t-butylperoxybenzoate, di-t- Butylperoxy-diisopropylbenzene, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di-t-butylperoxyhexane, di-t-butylperoxide, 2,5-dimethyl-2,5-di -T-butylperoxyhexyne-3 and the like. These may be used alone or in combination of two or more. Among these, 2,5-dimethyl-2,5-di-t-butylperoxyhexane is preferably used since the odor of the cross-linked product is small.

  The proportion of the peroxide crosslinking agent (component C) is 1 to 20 parts with respect to 100 parts by weight (hereinafter abbreviated as “part”) of the total amount of the ACM (component A) and FKM (component B). It is preferable to set it as the range. That is, if the peroxide crosslinking agent is less than 1 part, crosslinking is insufficient and the hose strength is inferior. Conversely, if the peroxide crosslinking agent exceeds 20 parts, it becomes too hard and the flexibility of the hose is increased. This is because an inferior tendency is seen.

  The resorcinol-based compound (component D) used together with the ACM, FKM and peroxide crosslinking agent is not particularly limited as long as it mainly acts as an adhesive. For example, modified resorcin / formaldehyde resin, resorcin, resorcin -For example, formaldehyde (RF) resin. These may be used alone or in combination of two or more. Of these, modified resorcin / formaldehyde resin is preferably used in terms of transpiration, hygroscopicity, and compatibility with rubber.

  Examples of the modified resorcin / formaldehyde resin include those represented by the following general formulas (1) to (3). Among these, those represented by the following general formula (1) are particularly preferable.

  The blending ratio of the resorcinol-based compound (component D) is preferably in the range of 0.5 to 10 parts with respect to 100 parts of the total amount of the ACM (component A) and FKM (component B). Preferably it is 1-5 parts. That is, if the resorcinol compound is less than 0.5 part, the adhesion to the polyamide resin layer is poor, and conversely if the resorcinol compound exceeds 10 parts, the cost increases.

  In addition, in the rubber composition for forming the outermost layer 3, the melamine resin (E component) is blended together with the resorcinol compound (D component) so that the interlayer adhesiveness with the polyamide resin layer is more excellent. Therefore, it is preferable.

  That is, the melamine-based resin (E component) used together with the components A to D is not particularly limited as long as it mainly acts as an adhesion assistant. For example, methylated formaldehyde / melamine polymer, hexamethylene Tetramine and the like. These may be used alone or in combination of two or more. Of these, methylated formaldehyde / melamine polymers are preferably used in terms of transpiration, hygroscopicity, and compatibility with rubber.

  As the methylated product of the formaldehyde / melamine polymer, for example, those represented by the following general formula (4) are preferably used.

  Among the melamine resins (component E), a mixture of the compounds represented by the general formula (4) is preferable, the compound with n = 1 is 43 to 44% by weight, and the compound with n = 2 is 27 to 27%. A mixture of 30 to 30% by weight of a compound of 30% by weight and n = 3 is particularly preferred.

  Moreover, the compounding ratio of the resorcinol compound (D component) and the melamine resin (E component) may be in a range of D component / E component = 1 / 0.5 to 1/2 by weight ratio. More preferably, D component / E component = 1 / 0.6 to 1 / 1.5. That is, when the weight ratio of the E component is less than 0.5, the tensile strength (TB) and the elongation (EB) of the rubber layer tend to be slightly deteriorated. If it exceeds the upper limit, the adhesiveness is saturated and the adhesive force is stabilized. Therefore, even if the weight ratio of the E component is further increased, only the cost is increased, and no further effect can be expected.

  The rubber composition for forming the outermost layer 3 includes, in addition to the above components, carbon black, process oil, anti-aging agent, processing aid, cross-linking accelerator, white filler, reactive monomer, foaming agent, etc. May be appropriately blended as necessary.

  The rubber composition for forming the outermost layer 3 is blended with the components A to D and, if necessary, other components (E component and the like), and is kneaded using a kneader such as a roll, a kneader, or a Banbury mixer. Can be prepared.

  And the hose shown in the said FIG. 1 can be manufactured as follows, for example. That is, first, the material for the inner layer 1 is extruded and then the polyamide resin is extruded to form the intermediate layer 2. Thereafter, the above-described special rubber composition (the material for the outermost layer 3) is extruded and vulcanized to produce a target hose.

  Moreover, the hose shown in the said FIG. 1 is not limited to said manufacturing method, It is also possible to coextrude these each layer.

  In the case of the hose shown in FIG. 2, since the intermediate layer is a polyamide resin reinforcing yarn layer 2 ′, the intermediate layer is formed by braiding polyamide resin reinforcing yarn on the outer peripheral surface of the inner layer 1. It is formed.

  The fuel hose of the present invention is not limited to the three-layer structure as shown in FIG. 1, but may have a laminated structure of the outermost layer and the polyamide resin layer on the inner peripheral surface thereof. Any configuration is acceptable. Therefore, the inner layer 1 in FIG. 1 may be composed of two or more layers, or may have a two-layer structure in which the inner layer 1 in FIG. 1 is omitted.

  Here, when the inner layer 1 is composed of two or more layers, fuel oil resistance and the like other than the innermost layer are not questioned. Therefore, the inner layer 1 may be formed of an appropriate resin, rubber, reinforcing yarn, or the like. it can.

  Next, examples will be described together with comparative examples.

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

[ACM (A component)]
VAMAC DP manufactured by DuPont

[FKM (B component)]
Daiel 901, manufactured by Daikin Industries

[Peroxide crosslinking agent (component C)]
2,5-dimethyl-2,5-di-t-butylperoxyhexane (manufactured by NOF Corporation, Perhexa 25B-40)

[Resorcinol compound (component D)]
Modified resorcin-formaldehyde resin represented by the general formula (1) (Sumitanol Chemical Industries, Sumikanol 620)

[Melamine resin (E component)]
Methylated formaldehyde / melamine polymer (Sumitomo Chemical Co., Ltd., Sumikanol 507A)

[Examples 1-4, Comparative Examples 1-3]
The components shown in Tables 1 and 2 below were blended in the proportions shown in the same table, and these were kneaded with a biaxial kneader to prepare a rubber composition for forming the outermost layer.

  Next, using the rubber composition, a hose was produced as follows. That is, first, the rubber composition for forming an inner layer was extruded into a hose shape. Subsequently, a reinforcing yarn made of polyamide 6 (Technola, manufactured by Teijin Ltd.) was wound around the surface in a spiral shape to form a reinforcing yarn layer. Furthermore, the rubber composition for outermost layer formation prepared above was extruded on the surface. Thereafter, steam heating was performed at 160 ° C. for 35 minutes, and hot air at 165 ° C. was further applied for 3 hours, followed by heat vulcanization to produce a target hose. The inner layer has a thickness of 1.5 mm, the outermost layer has a thickness of 1.5 mm, and the hose has an inner diameter of 13 mm.

  Using the hose of the example product and the comparative product obtained in this manner, each characteristic was evaluated according to the following criteria. These results are also shown in Table 3 below. The tensile strength (TB) and elongation (EB) of the rubber composition for forming the outermost layer are also shown.

[Tensile strength (TB), elongation (EB)]
The rubber composition was press vulcanized at 160 ° C. for 45 minutes to produce a vulcanized rubber sheet having a thickness of 2 mm. Subsequently, tensile strength (TB) and elongation (EB) were evaluated according to JIS K 6251 using a JIS No. 5 dumbbell. In addition, about tensile strength (TB) and elongation (EB), it is so favorable that a value is large.

[Thread-rubber adhesion]
The tip of the reinforcing yarn cut to 200 mm is sandwiched between the rubber compositions divided into a thickness of 3 mm, and the rubber composition is vulcanized (160 ° C. x 35 minutes of steam heating, and then heated with 165 ° C. hot air for 3 hours. Heat vulcanization). The rubber layer side of the sample thus obtained was fixed, the reinforcing yarn was pulled at a speed of 50 mm / min, and the pulling force (kg / piece) was measured. At that time, the state of the reinforcing yarn was also visually observed. That is, the case where the thread breakage or the rubber layer was broken was evaluated as ◯, and the case where the thread breakage or the rubber layer was broken without the thread breakage was evaluated as x.

〔Flame retardance〕
A flame was applied to the outer peripheral surface of the hose (length 100 mm) with a gas burner. Then, after 30 seconds, the hose was released from the flame of the gas burner, and the time until the flame disappeared from the outer peripheral surface of the hose was measured. The flame retardant was evaluated as ◯ when the flame-out time was 0 to less than 5 seconds, △ when it was less than 5 to 30 seconds, and x when it was 30 to 180 seconds. did.

〔cost〕
When the index of FKM / ACM = 50/50 was set to 100, the case where the material cost was 100 or less was evaluated as ◯, and the case where it exceeded 100 was evaluated as ×.

  From the above results, the hose of the product of all the examples is excellent in flame retardancy because the outermost layer is a peroxide-crosslinked ACM and FKM using a rubber composition having a specific blending ratio. I understand that. Moreover, since the special rubber composition formed by using together a resorcinol type compound and a melamine resin is used for the said outermost layer, the adhesive force of a rubber layer and a polyamide resin layer is very high.

  On the other hand, the hose of Comparative Example 1 has a low FKM ratio and is inferior in flame retardancy. Conversely, the hose of Comparative Example 2 has an excessively high FKM ratio, which increases costs. Since the hose of Comparative Example 3 does not contain an adhesive component in the rubber composition, the adhesive force between the rubber layer and the polyamide resin layer is extremely low.

  The fuel hose of the present invention is used for transportation of fuels such as automobiles (gasoline, alcohol-mixed gasoline (gasohol), alcohol, hydrogen, LPG, CNG, etc.), in particular, common rail injection system (new diesel engine system). Excellent performance as a heat-resistant fuel hose for automobiles. In addition, it is very useful as a hose for a diesel particulate filter (DPF) system. In addition to fuel, for example, it can also be suitably used as an automotive air hose through which high-temperature air flows, such as a supercharger air hose.

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

Explanation of symbols

1 Inner layer 2 Middle layer 3 Outermost layer

Claims (2)

A fuel hose having a plurality of constituent layers, comprising a polyamide resin layer as a constituent layer in contact with the inner peripheral surface of the outermost layer, and the outermost layer comprising the following (A) to (D) as essential components And the component (A) and the component (B) are formed by a rubber composition blended in a weight ratio of (A) / (B) = 7/3 to 5/5. Fuel hose characterized by.
(A) Acrylic rubber (ACM).
(B) Fluoro rubber (FKM).
(C) Peroxide crosslinking agent.
(D) Resorcinol compound. The fuel hose according to claim 1, wherein the outermost layer is formed of a rubber composition containing the following component (E) together with the components (A) to (D).
(E) Melamine resin.

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