JP2011245773A - Hose for fuel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hose for fuel which is lightweight, has excellent low fuel permeability, is low-cost, and is excellent in adhesion between layers, flexibility, impact resistance at a low temperature and heat resistance.SOLUTION: The hose for fuels includes a tubular inner layer 1 composed of the following (A) and an outer layer 2 contacting the outer circumferential surface and composed of the following (B), and satisfies the following requirements (α) or (β), both layers being bonded between the layers wherein (A) is a resin composition containing an aromatic polyester resin as a major component; (B) is a resin composition containing at least either one of a polyolefin-based resin and a polyamide-based resin as a major component; the resin composition (B) contains amine-modified SEBS (requirement α); and the resin composition (A) contains amine-modified SEBS, and the resin composition (B) contains acid-modified SEBS (requirement β).

Description

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

  In recent years, the regulation of transpiration of fuel gas surrounding automobiles has become stricter, and various types of low-permeability fuel hoses have been studied. As such a fuel hose, a hose made of fluororesin has been used in the past. However, when more stringent fuel permeation performance is required, the thickness of the fluororesin layer has to be increased. Has the disadvantage of becoming expensive. Therefore, as a resin that is less expensive than fluororesin and has excellent low fuel permeability, for example, aromatic polyamide resins such as polyphenylene sulfide resin (PPS) and polyamide 9T (PA9T), and aromatics such as polybutylene terephthalate (PBT) Polyester resins are attracting attention. Various hoses having a low fuel permeation layer made of these resins have been proposed in recent years (see, for example, Patent Documents 1 to 3).

JP 10-138372 A JP 2003-287165 A Japanese Patent Laid-Open No. 2003-110736

  However, PPS and PBT have a high specific gravity, which leads to an increase in the weight of the hose as it is, and as a result, for example, it becomes difficult to contribute to improving the fuel consumption of an automobile. In addition, low-permeability resins such as PPS, PBT, and PA9T have high rigidity, and when only this is used as a hose having a single-layer structure, it is inferior in flexibility. Prone to occur. In order to solve such a problem, conventionally, the fuel low-permeability layer made of the above-described resin is made thin, and a layer made of a thermoplastic resin having excellent flexibility, such as polyamide resin or polyethylene resin, on its outer periphery. However, the present situation is that sufficient performance is still not obtained in terms of low-temperature impact properties.

  In addition, since the low fuel permeability resins listed above have poor adhesion to other materials, the low fuel permeability layer and the thermoplastic resin layer are usually laminated at the interface between the two layers. It is necessary to provide an adhesive layer. As a result, the manufacturing process is complicated by the amount of the adhesive layer, and the hose weight increases.

  The present invention has been made in view of such circumstances, and is a fuel hose that is lightweight, excellent in low fuel permeability, low in cost, and excellent in interlayer adhesion, flexibility, low temperature impact resistance, and heat resistance. The purpose is to provide

In order to achieve the above object, a fuel hose according to the present invention includes a tubular inner layer composed of the following (A) and an outer layer composed of the following (B) provided in contact with the outer peripheral surface thereof. This is a fuel hose that satisfies the following requirement (α) or (β) and has a configuration in which both layers are bonded to each other.
(A) The resin composition which has an aromatic polyester resin as a main component.
(B) A resin composition comprising as a main component at least one of a polyolefin-based resin and a polyamide-based resin.
(Α) The resin composition (B) contains amine-modified polystyrene-poly (ethylene / butylene) block-polystyrene [amine-modified SEBS].
(Β) The resin composition (A) contains amine-modified polystyrene-poly (ethylene / butylene) block-polystyrene [amine-modified SEBS], and the resin composition (B) is acid-modified polystyrene-poly (ethylene). / Butylene) block-polystyrene [acid-modified SEBS].

That is, in order to solve the above-mentioned problems, the present inventors have a lightweight, high flexibility, and the like on the outer periphery of an inner layer made of an aromatic polyester resin such as PBT which is advantageous in terms of low fuel permeation performance and price. By placing an outer layer made of polyolefin resin such as high density polyethylene (HDPE) or polyamide resin, we have started research and development of a hose that has excellent flexibility and can reduce the total weight of the hose and contribute to fuel efficiency improvement. However, when such a layer structure is adopted, as described above, the interlayer adhesion between the inner layer and the outer layer becomes a problem. Therefore, as a result of intensive studies to solve this problem, the present inventors have flexibly applied the outer layer by blending the outer layer material with a modified elastomer that is a counter ion modification of an aromatic polyester resin such as PBT. In addition to imparting properties, it was studied to obtain interlayer adhesion with the inner layer without an adhesive, and various experiments were repeated. As a result, when amine-modified SEBS having high compatibility with the outer layer material is blended in the outer layer material, the amino groups (NH ₂ groups) at both ends of the SEBS become carboxyl groups (COOH groups) at the aromatic polyester resin molecule terminal of the inner layer material. ) (Amide bond), and it was found that the desired interlayer adhesion was obtained. At this time, when an acid-modified SEBS modified with maleic anhydride or the like is blended in the inner layer material as an elastomer highly compatible with PBT, the modified groups (COOH groups) at both ends of the SEBS and the amine-modified Due to the reaction with amino groups at both ends of SEBS, a higher interlayer adhesion can be obtained. In addition, when this principle is used and an amine-modified SEBS is blended in an inner layer material made of an aromatic polyester resin such as PBT and an acid-modified SEBS is blended in an outer layer material, a high interlayer adhesion force is obtained as described above. Found out that

  As described above, the fuel hose of the present invention includes a tubular inner layer made of a resin composition mainly containing an aromatic polyester resin such as PBT, and a resin composition mainly containing a polyolefin resin or a polyamide resin. The outer layer-forming resin composition contains amine-modified SEBS [Requirement (α)], or the inner-layer-forming resin composition contains amine-modified SEBS, and the outer-layer-forming resin composition. The resin composition contains acid-modified SEBS [Requirement (β)]. Therefore, the fuel hose of the present invention has high interlayer adhesion, is lightweight, has excellent fuel low permeability, and is excellent in flexibility, low temperature impact resistance, and heat resistance. In addition, the fuel hose of the present invention can be bonded between the layers without using an adhesive, and the material cost is low. Costing can be achieved.

  In particular, when the above requirement (α) is satisfied and the acid-modified SEBS is contained in the inner layer forming resin composition, a higher interlayer adhesion can be obtained.

  Further, when the layer containing the modified SEBS described in the requirement (α) or (β) is made of an alloy material having the modified SEBS as an island phase (domain), higher interlayer adhesion can be obtained.

  Further, when an innermost layer made of a fluororesin is further provided on the inner peripheral surface of the inner layer, the fuel has low fuel permeability.

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

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

The fuel hose of the present invention is configured, for example, by laminating an outer layer 2 on the outer peripheral surface of a tubular inner layer 1 through which fuel flows, as shown in FIG. The inner layer 1 is composed of the following (A), the outer layer 2 is composed of the following (B), satisfies the following requirements (α) or (β), and both layers are bonded to each other. Take. In addition, the “main component” of the resin composition of the following (A) and (B) has a great influence on the characteristics of the entire resin composition, and in the present invention, 50% by weight or more of the whole Means.
(A) The resin composition which has an aromatic polyester resin as a main component.
(B) A resin composition comprising as a main component at least one of a polyolefin-based resin and a polyamide-based resin.
(Α) The resin composition (B) contains amine-modified polystyrene-poly (ethylene / butylene) block-polystyrene [amine-modified SEBS].
(Β) The resin composition (A) contains amine-modified polystyrene-poly (ethylene / butylene) block-polystyrene [amine-modified SEBS], and the resin composition (B) is acid-modified polystyrene-poly (ethylene). / Butylene) block-polystyrene [acid-modified SEBS].

  In the case where the above requirement (α) is satisfied, the content ratio of the amine-modified SEBS in the resin composition (B) which is the material for the outer layer 2 is preferably in the range of 1.5 to 50% by weight, more preferably, It is in the range of 5 to 20% by weight. That is, if it is less than the above range, the desired interlayer adhesion effect cannot be obtained. Conversely, if the above range is exceeded, the outer layer material is a fuel oil [for example, Fuel C / M15 (Fuel C: methanol = 85 Volume%: 15 volume% mixed fuel liquid)].

  Moreover, when satisfy | filling the said requirement ((alpha)), when the resin composition (A) which is a material for inner layers 1 contains acid-modified SEBS, higher interlayer adhesive force will be obtained, and it is preferable. . However, since the inner layer 1 provides low fuel permeation performance, the amount of the acid-modified SEBS is preferably less than 50% by weight of the resin composition (A) so as not to hinder the performance.

  On the other hand, when the above requirement (β) is satisfied, the content of the amine-modified SEBS in the resin composition (A) is in the range of 2.0 to 30% by weight, and the content of the acid-modified SEBS in the resin composition (B). Is preferably in the range of 1.5 to 50% by weight. More preferably, the content of the amine-modified SEBS in the resin composition (A) is in the range of 5 to 20% by weight, and the content of the acid-modified SEBS in the resin composition (B) is in the range of 5 to 20% by weight. is there. By setting in this way, a desired interlayer adhesion effect can be obtained without hindering the low fuel permeation performance.

  Further, when the layer containing the modified SEBS described in the requirement (α) or (β) is made of an alloy material having the modified SEBS as an island phase (domain), higher interlayer adhesion can be obtained. Whether or not the layer is made of an alloy material can be confirmed by observation with a scanning electron microscope (SEM).

  Examples of the aromatic polyester resin used as the material for forming the inner layer 1 include polybutylene terephthalate (PBT), polybutylene naphthalate (PBN), polyethylene terephthalate (PET), and polyethylene naphthalate (PEN). These may be used alone or in combination of two or more. Among these, PBT is preferably used from the viewpoint of tube flexibility.

  Examples of the polyolefin resin used as the material for forming the outer layer 2 include high-density polyethylene (HDPE), low-density polyethylene (LDPE), polyethylene, polypropylene, polybutene, polymethylpentene, α-polyolefin, and modified polyolefin (anhydrous maleate). Polyethylene modified by acid, epoxy modification, etc.). These may be used alone or in combination of two or more. Of these, HDPE is preferably used from the viewpoint of high-temperature sealability.

  Examples of the polyamide resin used as the material for forming the outer layer 2 include polyamide 46 (PA46), polyamide 6 (PA6), polyamide 66 (PA66), polyamide 99 (PA99), polyamide 610 (PA610), polyamide 612 (PA612), polyamide 11 (PA11), polyamide 912 (PA912), polyamide 12 (PA12), a copolymer of polyamide 6 and polyamide 66 (PA6 / 66), a copolymer of polyamide 6 and polyamide 12 ( PA6 / 12), a copolymer of metaxylenediamine and adipic acid (PA-MXD6), a copolymer of hexamethylenediamine and terephthalic acid (PA6T), a copolymer of nonanediamine and terephthalic acid (PA9T), Between decanediamine and terephthalic acid Polymer (PA10T), co-polymers of undecane diamine and terephthalic acid (PA11T), co-polymers of dodecamethylenediamine and terephthalic acid (PA12T) and the like. These may be used alone or in combination of two or more.

  The amine-modified SEBS blended in the material for the inner layer 1 or the material for the outer layer 2 can be obtained, for example, by reacting SEBS with a modifier having an amino group at the end of the copolymerization and then hydrotreating. .

  The acid-modified SEBS blended in the material for the inner layer 1 or the material for the outer layer 2 is, for example, SEBS, carboxyl group, carbonyl group, thiocarbonyl group, carboxylic acid group, thiocarboxylic acid group, aldehyde group, thioaldehyde group. , Sulfonic acid groups, sulfonic acid ester groups, phosphoric acid groups, phosphoric acid ester groups, maleic anhydride groups, acrylic acid groups, methacrylic acid groups, carboxylic acid ester groups and the like are used. These may be used alone or in combination of two or more. Among the acid-modified SEBS, maleic anhydride-modified SEBS is preferably used because it has excellent reactivity with the resin that is the main component of the layer forming material.

  The material for the inner layer 1 and the material for the outer layer 2 include, as necessary, a pigment such as carbon black and titanium oxide, a filler such as calcium carbonate, a fatty acid ester, in addition to the resin and modified SEBS as the main components. , Plasticizers such as mineral oil, hindered phenolic antioxidants, antioxidants such as phosphorus heat stabilizers, lubricants such as stearic acid, calcium stearate, magnesium stearate, UV inhibitors, antistatic agents, organic fibers Further, a reinforcing agent such as glass fiber, carbon fiber and metal whisker, a flame retardant and the like may be contained.

  The fuel hose of the present invention shown in FIG. 1 can be produced, for example, as follows. That is, the inner layer 1 material and the outer layer 2 material as described above are prepared. At this time, when the modified SEBS is blended together with the resin as the main component of the layer forming material, the layer forming material is uniformly kneaded at 230 to 270 ° C. using a twin-screw kneading extruder (TEX30α manufactured by Nippon Steel). Need to be prepared. Next, using the extruder for the inner layer 1 and the extruder for the outer layer 2, each material is extruded and merged into one die, and this co-extruded molten tube is passed through a sizing die, so that the outer surface of the inner layer 1 is formed. A fuel hose having a two-layer structure in which the outer layer 2 is formed can be produced.

  In addition, when forming a hose in the shape of a bellows, it is possible to produce a bellows-like hose having a predetermined size by passing the co-extruded molten tube through a corrugating machine.

  In the fuel hose of the present invention thus obtained, the hose inner diameter is preferably in the range of 1 to 40 mm, particularly preferably in the range of 2 to 36 mm, and the hose outer diameter is preferably in the range of 2 to 44 mm. Particularly preferably, it is in the range of 3 to 40 mm. The thickness of the inner layer 1 is preferably in the range of 0.02 to 1.0 mm, particularly preferably in the range of 0.05 to 0.6 mm. The thickness of the outer layer 2 is preferably in the range of 0.03 to 1.5 mm, particularly preferably in the range of 0.05 to 1.0 mm.

  Note that the fuel hose of the present invention is not limited to the two-layer structure as shown in FIG. 1. For example, the fuel hose is formed in a three-layer structure in which the innermost layer is formed on the inner peripheral surface of the inner layer 1. Is also possible.

  And it is preferable that the innermost layer is made of a fluororesin because the fuel hose of the present invention is more excellent in low fuel permeability. Examples of the fluorine resin include polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (CTFE), polytetrafluoroethylene (PTFE), and tetrafluoroethylene / hexafluoro copolymer. (FEP), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene / hexafluoropropylene / vinylidene fluoride copolymer (THV), ethylene / tetrafluoroethylene copolymer (ETFE), Copolymers such as ethylene and polychlorotrifluoroethylene copolymer (ECTFE), modified copolymers thereof, various graft polymers and blends, and carbon black, carbon fiber, carbon nano Tube was added a conductive polymer or the like, conductive conductivity is imparted fluorine-based resins. These may be used alone or in combination of two or more.

  The fuel hose of the present invention in which the innermost layer is formed on the inner peripheral surface of the inner layer 1 can be produced, for example, as follows. That is, by preparing an innermost layer material, using an innermost layer extruder, the material is extruded together with the forming material of each layer and merged into one die, and this co-extruded molten tube is passed through a sizing die, whereby the inner layer 1 A fuel hose having an innermost layer formed on the inner peripheral surface can be produced.

  The thickness of the innermost layer is preferably in the range of 0.03 to 0.5 mm, particularly preferably in the range of 0.05 to 0.3 mm.

  Further, the fuel hose of the present invention may have a structure in which the outermost layer is formed on the outer periphery of the outer layer 2 as necessary.

  The fuel hose of the present invention is preferably used as a transportation hose for automobile fuel such as gasoline, alcohol-mixed gasoline, diesel fuel, CNG (compressed natural gas), LPG (liquefied petroleum gas), but is not limited thereto. It can be used as a fuel transportation hose for fuel cell vehicles such as methanol, hydrogen and dimethyl ether (DME).

  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.

[PBT]
DURANEX 700FP, manufactured by Polyplastics

[PBN]
TQB-OT, manufactured by Teijin Chemicals

[PEN]
Teonex 8065S, made by Teijin Chemicals

[PET]
Novapex GG900, manufactured by Mitsubishi Chemical Corporation

[HDPE]
Novatec HB111R, manufactured by Nippon Polyethylene

[Amine-modified SEBS]
Tuftec M10, manufactured by Asahi Kasei Chemicals

[Acid-modified SEBS]
Tuftec M1913, manufactured by Asahi Kasei Chemicals

[PA12]
Rilsan AESN P20TL, manufactured by Arkema

[Fluorine resin]
NEOFLON RP5000, manufactured by Daikin Industries

[Conductive fluororesin]
NEOFLON RP5000AS, made by Daikin Industries

  Next, a hose was produced using the above materials as shown below.

[Examples 1-14, Comparative Examples 1-7]
The innermost layer materials (only Examples 13 and 14), inner layer materials, and outer layer materials shown in Tables 1 to 4 below are prepared, and the above materials are hot melt extruded from each extruder filled with these materials. A smooth hose having an inner diameter of 6 mm was produced by (co-extrusion) and merging into one die and passing this through a sizing die. In addition, in the case where the layer forming material is not described in Tables 1 to 4, the layer is not formed. In Tables 1 to 4 below, the layer forming material containing modified SEBS together with polymers such as PBT, HDPE, and PA12 is a twin-screw kneading extruder (Nippon Steel Works) at a weight ratio (wt%) shown in the same table. Further, the cured material of the layer forming material is an alloy having the above-described polymer as a sea phase (matrix) and a modified SEBS as an island phase (domain). The material is confirmed by observation with a scanning electron microscope (SEM). Further, when the produced smooth hose has a one-layer structure, the thickness of the layer is 1 mm. When the two-layer structure is used, the inner layer has a thickness of 0.3 mm / outer layer has a thickness of 0.7 mm. The thickness of the inner layer was 0.05 mm / the thickness of the inner layer was 0.25 mm / the thickness of the outer layer was 0.7 mm.

  Using the hoses of Examples and Comparative Examples thus obtained, each characteristic was evaluated according to the following criteria. These results are shown in Tables 5 to 8 below.

[Fuel resistance]
Each hose was cut into a strip shape with a width of 10 mm to prepare a sample. The sample was immersed in Fuel C / M15 (Fuel C: methanol = 85% by volume: 15% by volume of mixed fuel liquid) at 60 ° C. for 168 hours. Then, the dissolution state of each layer of the sample after the immersion was visually evaluated, and the case where each layer did not dissolve was evaluated as ◯, and the case where dissolution was observed in any layer was evaluated as ×.

[Fuel permeation amount]
For each hose, simulated alcohol in which toluene / isooctane / ethanol was mixed at a ratio of 45:45:10 (volume ratio) using an isobaric hose permeability measuring device (GTR-TUBE3-TG, manufactured by GTR Tech). The permeability coefficient of the added gasoline was measured at 40 ° C. for one month (unit: mg / m / day). In addition, the value described in the table is a value when equilibrium is reached. Then, this value was evaluated as ○ when the value was less than 50 (mg / m / day) and × when the value was 50 (mg / m / day) or more.

[Interlayer adhesion]
Each hose was cut into a strip shape with a width of 10 mm to prepare a sample. Then, the layers of the samples (inner layers / outer layers in Examples 1 to 12 and Comparative Examples 3 to 6; innermost layer / inner layer and inner layers / outer layers in Examples 13 and 14) are peeled off. Each was sandwiched between chucks of a tensile tester, and the 180 ° peel strength (N / cm) was measured under the condition of a tensile speed of 50 mm / min. Note that if the peel strength is 20 N / cm or more, a target value that the interlayer adhesion is good is set. In the evaluation, “◯” is indicated, and those having a peel strength of 15 N / cm to less than 20 N / cm are Δ, and less than 15 N / cm. Was rated as x. In the present invention, an evaluation (◯ and Δ) of Δ or higher is required.

[Low temperature flexibility]
Each hose was allowed to stand in a low temperature (−40 ° C.) environment for 24 hours, and then the hose was bent at 90 °. As a result, the case where an abnormality such as a crack or a break was observed in the hose was evaluated as x, and the case where the abnormality was not observed was evaluated as ◯.

  From the above results, it can be seen that all of the example products have a small amount of fuel permeation and excellent fuel oil resistance, interlayer adhesion, and low temperature flexibility.

  On the other hand, the product of Comparative Example 1 having a PBT single layer structure is inferior in low-temperature flexibility. The product of Comparative Example 2 having an HDPE single-layer structure is excellent in low-temperature flexibility, but has high fuel permeability and is not suitable for use as a fuel hose. The product of Comparative Example 3 has a laminated structure of a PBT inner layer and an HDPE outer layer, but both layers do not contain modified SEBS and are inferior in interlayer adhesion and low temperature flexibility. The product of Comparative Example 4 has a laminated structure of the PBT inner layer and the amine-modified SEBS outer layer, but dissolution of the outer layer material occurred in the fuel oil resistance test. The product of Comparative Example 5 has a laminated structure of the PBT inner layer and the acid-modified SEBS outer layer, but as described above, the outer layer material is dissolved in the fuel oil resistance test, and is inferior in interlayer adhesion and low-temperature flexibility. The product of Comparative Example 6 has a laminated structure of a PBT inner layer and a PA12 outer layer, but both layers do not contain modified SEBS, and are inferior in interlayer adhesion and low temperature flexibility. The product of Comparative Example 7 has a PA12 single-layer structure, has high fuel permeability, and is not suitable for a fuel hose application.

  The fuel hose of the present invention can be suitably used as a transportation hose for automobile fuel such as gasoline, alcohol-mixed gasoline, diesel fuel, CNG (compressed natural gas), LPG (liquefied petroleum gas) and the like.

1 Inner layer 2 Outer layer

Claims (6)

A fuel hose comprising a tubular inner layer made of the following (A) and an outer layer made of the following (B) provided in contact with the outer peripheral surface thereof, wherein the following (α) or (β) A fuel hose that meets the requirements and has two layers bonded together.
(A) The resin composition which has an aromatic polyester resin as a main component.
(B) A resin composition comprising as a main component at least one of a polyolefin-based resin and a polyamide-based resin.
(Α) The resin composition (B) contains amine-modified polystyrene-poly (ethylene / butylene) block-polystyrene [amine-modified SEBS].
(Β) The resin composition (A) contains amine-modified polystyrene-poly (ethylene / butylene) block-polystyrene [amine-modified SEBS], and the resin composition (B) is acid-modified polystyrene-poly (ethylene). / Butylene) block-polystyrene [acid-modified SEBS].   2. The fuel hose according to claim 1, wherein the fuel hose according to claim 1 satisfies the requirement (α), and the content ratio of the amine-modified SEBS in the resin composition (B) is in the range of 1.5 to 50% by weight.   The fuel hose according to claim 1, wherein the resin composition (A) contains acid-modified SEBS while satisfying the requirement (α).   Satisfying the above requirement (β), the content of amine-modified SEBS in the resin composition (A) is in the range of 2.0 to 30% by weight, and the content of acid-modified SEBS in the resin composition (B) is 1. The fuel hose according to claim 1, which is in the range of 5 to 50% by weight.   The fuel-containing layer according to any one of claims 1 to 4, wherein the layer containing the modified SEBS according to the requirement (α) or (β) is made of an alloy material having the modified SEBS as an island phase (domain). hose.   The fuel hose according to any one of claims 1 to 5, further comprising an innermost layer made of a fluorine-based resin on the inner peripheral surface of the inner layer.

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