JP5671782B2 - Rubber hose for fuel transportation - Google Patents

Description

  The present invention relates to a rubber hose excellent in oil resistance, chemical resistance and heat resistance, and more particularly to a rubber hose for fuel transportation suitably used in a fuel system for automobiles, a household cogeneration system, and the like.

  A rubber hose is a member that is indispensable as an industrial material for transporting fluids, transmitting pressure, and the like, and is formed by vulcanization molding into a tubular shape by combining compounded rubber and reinforcing materials such as fibers and wires. Its applications range from construction, agriculture, automobiles, foods, etc. Recently, with the advancement of equipment and systems, etc., and longer life, chemical resistance, pressure resistance, wear resistance, flexibility, heat resistance, etc. As the quality requirements of the hose have further increased, there is a need for a hose with higher durability.

  Due to the required characteristics of the rubber hose, normally, an inner rubber layer made of rubber through which fluid flows or is filled from the inside, a reinforcing layer for withstanding the pressure of the fluid, and the reinforcing layer and the inner rubber layer are damaged from the outside. It has a laminated structure in which an outer rubber layer that prevents it from being sequentially laminated. Moreover, providing the said reinforcement layer in multiple layers as needed is generally performed, and the improvement of durability is achieved. Thus, improving the durability of the rubber hose leads to an extended maintenance period of the connected equipment, and can reduce costs associated with the replacement of the hose, waste discharge amount, disposal cost, etc. It is also preferable from the viewpoint of cost and environment.

  For example, a fuel hose for transporting fuel such as gasoline and kerosene is required to have mainly excellent oil resistance, chemical resistance and heat resistance from the usage environment such as in an engine room of an automobile. Therefore, acrylonitrile-butadiene rubber (NBR) having excellent oil resistance is generally used as the rubber (particularly the inner rubber layer) forming the fuel hose. In addition, conventionally, it has been generally performed to further improve oil resistance by forming a liquid contact layer made of a chemically stable fluororesin further inside the inner rubber layer. However, in general, it has been difficult to firmly bond the fluororesin to the rubber material forming the inner rubber layer because of its chemical properties.

  In addition, the fuel hose is required to have flexibility that allows easy construction even in a narrow space such as an engine room of an automobile and a small minimum bending radius. That is, the fuel hose may be bent forcibly during construction or may be subjected to external force due to contact with surrounding members, in which case the hose bends and kinks are generated. Sometimes. If kinks occur, the flow path may be narrowed and fuel transportation may be restricted. Further, if the flow path is completely blocked, transportation itself may not be possible. In addition, when the adhesion between the fluororesin and the inner rubber layer is insufficient, there is a possibility that peeling occurs at both portions where kinks are generated, resulting in early damage.

  In general, fluororesins are poor in flexibility, so that they do not impair the flexibility and durability of the hose when used as a wetted layer of a hose, which is an important commodity element. In addition, it is important that the liquid contact layer is formed as thin as possible and is firmly adhered to the rubber forming the inner rubber layer. Conventionally, as a method for firmly bonding a fluororesin and a rubber material, a chemical pretreatment such as a corona discharge treatment is applied to the surface of the fluororesin, and then a one-component adhesive or an undercoat adhesive is bonded to an overcoat. In many cases, a method of applying a two-component adhesive comprising an agent is employed. However, since the above method requires many steps in production, there are many technical problems and a large cost burden.

  On the other hand, various techniques for solving the problem in the above-described adhesion have been proposed. For example, a formulation in which a carboxylic acid having a specific structure is blended with the rubber (inner surface rubber layer) and / or the fluorine-based resin (wetted layer) (Patent Document 1: Japanese Patent Laid-Open No. 58-162335) or , A prescription containing an epoxy resin and imidazole (Patent Document 2: Japanese Patent Laid-Open No. 2-85591), a prescription containing a tetraalkyl fosonium benzothiazolium (TRP-BT) (Patent Document 3: Japanese Patent Laid-open No. Hei 5). -193053) and the like. By laminating the wetted layer, the inner rubber layer, the reinforcing layer, and the outer rubber layer using extrusion molding or the like by these techniques, the resulting laminate is vulcanized to obtain the above pretreatment step and adhesive. Although it has become possible to vulcanize and bond rubber and fluororesin firmly without going through the coating process, further improvement in adhesion is necessary to achieve the durability currently required. .

  In addition, as a technique for firmly bonding the fluororesin and the rubber material, the applicant relates to a hot water supply hose or a refrigerant transport hose, a fluororesin having a carboxyl group and / or an acid anhydride group as a liquid contact layer, By using an acrylic rubber having a carboxyl group and / or an acid anhydride group as a cross-linking site and a rubber composition containing a polyamine as a cross-linking site, a strong chemical bond is formed between the two layers by amine cross-linking. Thus, a technique for improving adhesion and greatly improving the durability of the hose has been proposed (Patent Document 4: Japanese Patent Laid-Open No. 2007-326248, Patent Document 5: Japanese Patent Laid-Open No. 2008-94947).

JP 58-162335 A Japanese Patent Laid-Open No. 2-85591 JP-A-5-193053 JP 2007-326248 A JP 2008-94947 A

  The present invention has been made in view of the above circumstances, and the fluororesin that forms the liquid contact layer and the rubber that forms the inner rubber layer on the outside thereof are firmly bonded to each other, and are oil resistant, chemical resistant, and heat resistant. Another object of the present invention is to provide a rubber hose excellent in durability and excellent in durability, in particular, a rubber hose for fuel transportation that can be suitably used for a fuel system of an automobile.

  In order to solve the above problems, the present inventor has focused on a new bonding method between a fluorine resin material and rubber, and as a result, the fluorine resin chemically modified with an acid anhydride such as maleic anhydride and a carboxyl group are crosslinked. It has been found that extremely good adhesiveness can be easily obtained by vulcanizing and adhering a hydrogenated NBR (HNBR) as a site to a rubber composition containing a polyamine as a crosslinking agent in close contact.

  The present inventor has further studied, such as a fluorine-based resin having a carboxyl group and / or an acid anhydride group, a hydrogenated NBR (HNBR) having a carboxyl group and / or an acid anhydride group as a crosslinking site, and a diamine. By adhering and vulcanizing and adhering a rubber composition containing a polyamine cross-linking agent, a cross-linked structure consisting of an imide bond or the like is formed between the fluororesin and the rubber when the rubber composition is heat vulcanized. As a result, the inventors have found that the fluororesin and the HNBR can be firmly bonded, and have reached the present invention.

That is, the present invention provides the following inventions (1) to (4).
(1) A fuel transport rubber hose comprising at least an inner rubber layer, a reinforcing layer formed outside the inner rubber layer, and an outer rubber layer formed outside the reinforcing layer. Further, a wetted layer made of a fluororesin is formed on the inner side, and the wetted layer is a fluororesin having a carboxyl group and / or an acid anhydride group, and the inner rubber layer has a carboxyl group as a crosslinking site. and / or has an acid anhydride group, an acrylonitrile content of 20 to 50 wt%, and the hydrogenated acrylonitrile water hydride ratio is 95% or more - butadiene rubber (HNBR), crosslinked with a crosslinking agent consisting of a polyamine A rubber hose for fuel transportation , characterized by being rubber.
(2) The rubber hose for fuel transportation according to the above (1), wherein the fluororesin is a maleic anhydride-modified ethylene-tetrafluoroethylene copolymer (maleic anhydride-modified ETFE).
(3) The rubber hose for fuel transportation according to (1) or (2), wherein the HNBR is modified with maleic acid or an anhydride thereof.
(4) The above (1) to (1), wherein the crosslinking agent is one or more crosslinking agents selected from diaminodiphenylmethane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, and hexamethylenediamine carbamate. The rubber hose for fuel transportation according to any one of (3).

  The rubber hose of the present invention is excellent in oil resistance, chemical resistance and heat resistance. In addition, since the liquid contact layer and the inner rubber layer form a cross-linked structure and are firmly bonded to each other, peeling does not occur between them and the durability is excellent.

It is a schematic perspective view which shows one Example of the structure of the rubber hose of this invention. It is a schematic perspective view which shows another Example of the structure of the rubber hose of this invention.

  The rubber hose of the present invention is a rubber hose comprising at least an inner rubber layer, a reinforcing layer formed outside the inner rubber layer, and an outer rubber layer formed outside the reinforcing layer. Furthermore, a liquid contact layer made of a fluorine resin is formed on the inner side.

Hereinafter, the present invention will be described more specifically with reference to the drawings.
FIG. 1 is a schematic perspective view showing an embodiment of the structure of the rubber hose of the present invention. The rubber hose 1 of the present invention has a laminated structure in which a liquid contact layer 2, an inner rubber layer 3, a reinforcing layer 4 and an outer rubber layer 5 made of a fluororesin are sequentially laminated from the inside. The diameter of the rubber hose in FIG. 1 is appropriately set according to the use location and purpose of the hose and is not particularly limited, but here the outer diameter is about 10 to 16 mm.

  The liquid contact layer 2 is formed of a fluorine-based resin having a carboxyl group and / or an acid anhydride group. As the fluorine-based resin, a known one can be used, and is not particularly limited. As specific examples, polyvinyl fluoride, polyvinylidene fluoride, polyfluorinated ethylene, polychloroethylene trifluoride, tetrafluoroethylene-hexafluoropropylene copolymer, ethylene-tetrafluoroethylene copolymer, ethylene- Crystalline fluororesin such as ethylene chloride trifluoride copolymer, tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride terpolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, or fluororesin rubber And a soft fluororesin obtained by graft polymerization. In the present invention, an ethylene-tetrafluoroethylene copolymer (ETFE) can be suitably used from the viewpoints of flexibility and heat resistance.

  The carboxyl group and the acid anhydride group are formed by chemically modifying the fluororesin with a carboxylic acid such as maleic acid or the acid anhydride thereof. In this case, the acid anhydride group of the carboxylic acid is preferable in order to take a crosslinked structure composed of a rubber component and an imide bond described later. In addition, the fluororesin having the carboxyl group and / or acid anhydride group may be used singly, or is chemically modified with a different carboxylic acid or acid anhydride, or has a different degree of chemical modification. Two or more may be mixed and used.

  If the thickness of the liquid contact layer 2 is too thin, the oil resistance, chemical resistance, heat resistance and the like may be insufficient. On the other hand, if the thickness is too thick, the flexibility of the hose may be impaired. In the present invention, the thickness is preferably 50 to 300 μm.

  The rubber forming the inner rubber layer 3 is made of polyamine using hydrogenated acrylonitrile-butadiene rubber (HNBR) having a carboxyl group and / or an acid anhydride group as a crosslinking site as a rubber component from the viewpoint of oil resistance and the like. A crosslinking agent is blended and vulcanized (crosslinked).

  The acrylonitrile content (AN content) of the HNBR is preferably 20 to 50% by mass, more preferably 25 to 35% by mass from the viewpoint of oil resistance and the like. If the AN content is less than 20% by mass, sufficient oil resistance may not be obtained. On the other hand, if the AN content exceeds 50% by mass, the low temperature property of the rubber composition (increased embrittlement temperature), resin, There is a risk that the mechanical properties become strong and the elasticity inherent in rubber is impaired.

  The hydrogenation rate of the HNBR is not particularly limited, but is preferably 95% or more, more preferably 98% or more from the viewpoint of heat resistance. If the hydrogenation rate is less than 95%, the heat resistance may be impaired.

  The carboxyl group and acid anhydride group are formed by chemically modifying HNBR with a carboxylic acid such as maleic acid or an acid anhydride thereof. In this case, the acid anhydride group of the carboxylic acid is preferable, and the acid anhydride group of maleic acid is particularly preferable in order to have a cross-linked structure composed of the fluororesin and an imide bond. In addition, the HNBR having the carboxyl group and / or acid anhydride group may be used alone, or two that are chemically modified with different carboxylic acids or acid anhydrides or those having different degrees of chemical modification. You may mix and use seeds or more.

  As the cross-linking agent, known polyamines can be used and are not particularly limited. Specifically, diaminodiphenylmethane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, hexa Examples include diamines such as methylenediamine carbamate, and triethylenetetramine. These polyamines can be used alone or in combination of two or more. In the present invention, diaminodiphenylmethane and 2,2-bis [4- (4-aminophenoxy) phenyl] propane are preferably used. Can be used. The amount of the polyamine is not particularly limited as long as it is sufficient to form rubber vulcanization and the crosslinked structure, but 1 to 8 parts by mass with respect to 100 parts by mass of the rubber component. The amount is preferably 2 to 6 parts by mass. When the blending amount is less than 1 part by mass, not only a sufficient crosslinking density cannot be obtained, but there is a possibility that sufficient adhesion with a fluorine-based resin such as acid-modified ETFE may not be obtained. The crosslink density is excessively increased, the rubber hardness is increased, and brittleness may be increased. In addition, the cost may increase and the economy may be impaired.

  In the present invention, the above-mentioned fluororesin having a carboxyl group and / or an acid anhydride group, a rubber composition containing HNBR having a carboxyl group and / or an acid anhydride group as a crosslinking site and a polyamine as a crosslinking agent. By contacting and heating to the vulcanization temperature of the rubber, the rubber composition is vulcanized and cured, and the carboxyl group and / or acid anhydride group of the fluororesin, the carboxyl group of the crosslinking site of HNBR, and It is possible to obtain a fluororesin / rubber composite material in which an acid anhydride group and a polyamine as a crosslinking agent form a cross-linked structure composed of an imide bond or the like, and the fluororesin and rubber are firmly bonded and bonded. it can.

  Further, in the present invention, for the rubber component, known vulcanizing agents, vulcanization accelerators and vulcanization acceleration aids, commonly used carbon, anti-aging agents, plasticizers, petroleum resins, vulcanization delays. Additives such as additives, waxes, antioxidants, fillers, oils, lubricants, tackifiers, ultraviolet absorbers, dispersants, compatibilizing agents, homogenizing agents and the like can be appropriately blended.

  As the carbon, known carbon blacks such as SRF, GPF, FEF, HAF, ISAF, SAF, FT, and MT can be used. Moreover, these carbon blacks may be used individually by 1 type, and may use 2 or more types together. The compounding amount of the carbon black is 40 to 80 parts by mass with respect to 100 parts by mass of the rubber component.

  Plasticizers include known process oils such as aromatic oils, naphthenic oils, paraffin oils, vegetable oils such as palm oil and castor oil, synthetic oils such as alkylbenzene oils, ester plasticizers, ether plasticizers, etc. Can be used. These can be used alone or in combination of two or more. The compounding amount of the plasticizer is 5 to 25 parts by mass with respect to 100 parts by mass of the rubber component.

  A known vulcanization accelerator can be used, and is not particularly limited. For example, N-cyclohexyl-2-benzothiazylsulfenamide, Nt-butyl-2-benzothia Addition of sulfenamide-based vulcanization accelerators such as dilsulfenamide and Nt-butyl-2-benzothiazylsulfenimide, and guanidine-based additions such as 1,3-di-o-tolylguanidine and diphenylguanidine Sulfur accelerators, thiuram vulcanization accelerators such as tetramethylthiuram disulfide, tetramethylthiuram monosulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, and vulcanization accelerators such as zinc dialkyldithiophosphate. The compounding quantity of the said vulcanization accelerator shall be 1-4 mass parts with respect to 100 mass parts of said rubber components.

  In the present invention, the thickness of the inner rubber layer 3 is preferably 0.8 to 2 mm. If it is too thin, there is a risk of adversely affecting the hose crimping performance. If it is too thick, the hose weight increases and the hose outer diameter increases. It may lead to an increase in dimensions.

  A known material can be used as the constituent material of the reinforcing layer 4 and is not particularly limited. Specifically, the metal is made of a simple metal such as iron, copper, or aluminum, or an alloy such as stainless steel. Reinforcing yarns made of organic fibers such as hard wire, polyethylene terephthalate (PET) fiber, polyethylene naphthalate (PEN) fiber, nylon fiber, and aramid fiber can be used. The reinforcing layer 4 is formed by braiding or spirally winding one of these alone, or by spirally winding the two or more in a braided or mutually paired direction.

  In this case, the diameter of the metal hard wire is not particularly limited, but is preferably 0.1 to 0.5 mm in the present invention. If the wire diameter of the metal hard wire is less than 0.1 mm, it becomes easy to bite when the reinforcing layer 4 is formed by wrapping around the outer peripheral surface of the inner rubber layer 3, which may cause pinholes or breakage There is. Moreover, when the wire diameter of the said metal hard wire exceeds 0.5 mm, it is too thick, workability falls, and there exists a possibility that it may become difficult to form the reinforcement layer 4. FIG.

  Further, the fineness of the organic fiber reinforcing yarn is not particularly limited, but is preferably 1100 to 3300 dtex in the present invention. If the fineness of the reinforcing yarn is less than 1100 dtex, the strength and durability may be insufficient, and if it exceeds 3300 dtex, the shape of the reinforcing yarn (reinforcing layer) is raised on the outer peripheral surface of the molded rubber hose, The appearance of the rubber hose may be damaged.

  The reinforcing layer 4 may be composed of one layer of a hard metal wire or a braided layer 4a of reinforcing yarn, as shown in FIG. 1, and as shown in FIG. It is good also as a 2 layer structure comprised by the organic fiber reinforcement layer 4b which consists of a braided layer of a reinforcement yarn, and the metal hard wire reinforcement layer 4c which consists of a braided layer of a metal hard wire. When the reinforcing layer 4 has a two-layer structure, it is preferable from the viewpoint of manufacturing and appearance that the organic fiber reinforcing layer 4b is on the inner layer side of the reinforcing layer 4 and the metal hard wire reinforcing layer 4c is on the outer layer side. Further, in this case, although not particularly limited, an organic fiber reinforcing layer 4b braided with reinforcing yarns of 1100 to 3300 dtex, 6 to 15 twists / 10 cm, and a wire diameter of 0.1 to 0.5 mm An organic fiber reinforcing layer 4b formed by spirally winding a reinforcing yarn having a metal hard wire braided metal hard wire reinforcing layer 4c, 1100 to 3300 dtex, and a twist number of 0 to 10 times / 10 cm, and the wire diameter is It is preferable to form with the metal hard wire reinforcement layer 4c which braided the metal hard wire of 0.1-0.5 mm. In the present invention, by forming the reinforcing layer 4 having such a two-layer structure, excellent pressure resistance and durability can be obtained.

  Although not particularly shown, when the reinforcing layer 4 is formed on the outer peripheral surface of the inner rubber layer 3, an adhesive layer may be interposed as required. The adhesive layer can be provided by applying a known adhesive, whereby the displacement of the reinforcing layer 4 can be prevented and a rubber hose can be produced more stably.

  The outer rubber layer 5 can be formed of a known rubber material, and the material is not particularly limited. However, from the viewpoint of easiness of procurement of materials and setting of heat vulcanization conditions, the inner surface rubber layer 5 is formed. It is preferable to form the same material as the constituent material of the rubber layer 3.

  Further, the thickness of the outer rubber layer 5 can be appropriately set according to the specification of the hose and the like, and is not particularly limited, but is set to 0.5 to 1.5 mm in the present invention.

  The rubber hose of the present invention can be produced by a known production method, and the production method is not particularly limited, but specific examples include the following methods. First, the fluororesin having the above carboxyl group and / or acid anhydride group is extruded onto an mandrel coated with a release agent by an extruder to form a tubular fluororesin layer (wetted layer 2). . Next, the rubber composition is extruded onto the outer peripheral surface of the wetted layer 2 by an extruder to form an inner rubber layer 3 having a predetermined thickness, and a metal hard wire or reinforcing yarn is formed on the outer peripheral surface of the inner rubber layer 3. After forming the reinforcing layer 4, the outer rubber layer 5 is further formed on the outer peripheral surface of the reinforcing layer 4 in the same manner as the inner rubber layer 3, and the resulting laminate (unvulcanized rubber hose) Are heated and vulcanized according to a conventional method to bond and integrate the layers.

  In the rubber hose of the present invention, the surface of the wetted layer 2 is not formed on the outer peripheral surface of the wetted layer by extrusion molding or the like, without requiring a step such as surface treatment or adhesive coating for improving the adhesiveness of the adhesive surface of the fluororesin. Since the inner surface rubber layer 3 is formed and only the heat vulcanization is performed, the fluororesin of the liquid contact layer 2 and the inner surface rubber layer 3 are firmly bonded with a cross-linked structure such as an imide bond. A rubber hose having excellent durability without causing peeling can be efficiently produced.

  In the rubber hose of the present invention, the diameter (inner diameter, outer diameter) of the rubber hose, the thickness and structure of each layer are not limited to the above, and the specifications of the rubber hose are within the range not impairing the effects of the present invention. Can be set as appropriate according to the conditions. For example, as shown in FIG. 1, a four-layer structure in which a liquid contact layer 2, an inner rubber layer 3, a reinforcing layer 4, and an outer rubber layer 5 are sequentially laminated from the inside, or the reinforcing layer 4 as shown in FIG. 6 layers in which an intermediate layer (intermediate rubber layer) is disposed between the two reinforcing layers 4b and 4c of the rubber hose shown in FIG. Structures may be used, and these structures may be set as appropriate according to the required characteristics of the hose.

  The rubber hose of the present invention has a wide range of uses such as a fuel transport hose, a fuel supply hose, a chemical transport hose, a water supply and hot water supply hose due to its excellent oil resistance, chemical resistance, heat resistance, durability and workability (flexibility). In particular, it can be suitably used as a fuel transportation hose used in an engine room of an automobile because of its excellent oil resistance, chemical resistance and heat resistance.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated in detail, this invention is not restrict | limited to the following Example.

[Experiment 1 and Comparative Experiments 1 to 4]
First, the physical properties of the rubber material forming the inner rubber layer and the adhesion between the rubber material and the fluororesin were confirmed by the following method.
The rubber composition shown in Table 1 was prepared according to a conventional method, and then formed into a sheet having a length of 120 mm, a width of 120 mm, and a thickness of 2.2 mm. Subsequently, the obtained rubber sheet was subjected to primary vulcanization at 160 ° C. for 45 minutes and secondary vulcanization at 160 ° C. for 4 hours to obtain an evaluation body 1 for evaluating rubber physical properties. Further, as an evaluation body for evaluating adhesiveness, maleic anhydride-modified ETFE “LM-ETFE-AH-2000” manufactured by Asahi Glass Co., Ltd. as a fluororesin having a carboxyl group and / or an acid anhydride group on the rubber sheet. "After assembling" LM-ETFE "or" PFR "sheets (thickness 300 μm) manufactured by Asahi Glass Co., Ltd. as a fluorine-based resin having no carboxyl group and acid anhydride group, the same conditions as above The evaluation body 2 was produced by heating and vulcanization at

About the evaluation body produced above, it tested about the following items. The results are shown in Table 1.
"Evaluation method"
・ Hardness (JIS-A)
According to JIS K6253, the evaluation body 1 was measured with a type A durometer.
-Tensile strength and elongation at break In accordance with JIS K6251, a dumbbell-shaped No. 3 test piece was prepared from the evaluation body 1, and the tensile strength and the elongation at break were measured.
・ Heat resistance (tensile strength retention and breaking elongation retention)
After the evaluation body 1 was held in a thermostat at 150 ° C. for 500 hours, the tensile strength and breaking elongation were measured in the same manner as described above, and the ratio to the result measured under the conditions before heating was calculated. The closer this ratio is to 100, the smaller the deterioration of physical properties due to heat, and the better the heat resistance.
・ Adhesiveness (resin / rubber adhesiveness)
About the said evaluation body 2, the 180 degree peeling test was done at the tension speed of 50 mm / min, the state with rubber | gum of the adhesive surface of the peeled fluororesin sheet | seat was observed visually, and the following reference | standard evaluated.
A: Surface area with rubber 100%
○: Surface area with rubber ratio 80% or more △: Surface area with rubber ratio 50% or more X: Surface area with rubber ratio less than 50%

In addition, the detail of each compounding component in Table 1 is as follows.
Acid-modified HNBR: “ZPT-136” manufactured by Nippon Zeon Co., Ltd.
HNBR: “ZP2000L” manufactured by ZEON CORPORATION
NBR: “N230” manufactured by JSR Corporation
Acrylic rubber: “Vamac-G” manufactured by Dupont
Carbon black: “Seast 6” manufactured by Tokai Carbon Co., Ltd.
Anti-aging agent: “NOCRACK MB” manufactured by Ouchi Shinsei Chemical Co., Ltd.
Octadecylamine: “Armin 18D”
Polyoxyester ether phosphate: “Phosphanol RL210”
Plasticizer 1: "ADEKA SIZER C8" manufactured by ADEKA Corporation
Plasticizer 2: DOA
Plasticizer 3: "ADEKA SIZER RS735" manufactured by ADEKA Corporation
Diaminodiphenylmethane: “DAM” manufactured by Hodogaya Chemical Co., Ltd.
Accelerator DOTG: “Noxeller DT” manufactured by Ouchi Shinsei Chemical Co., Ltd.
Organic peroxide crosslinking agent: NOF Corporation "Park Mill D-40"
Co-crosslinking agent: “Barunok PM” manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
Sulfur crosslinker: 5% zinc oxide mixed sulfur accelerator DPG: “Noxeller D” manufactured by Ouchi Shinsei Chemical Co., Ltd.
Accelerator CZ: “Noxeller CZ” manufactured by Ouchi Shinsei Chemical Co., Ltd.

  From the results in Table 1 above, HNBR having a carboxyl group and / or an acid anhydride group as a crosslinking site is excellent in mechanical strength, and a carboxyl group and / or an acid anhydride group is added by adding a crosslinking agent made of polyamine. It was confirmed that it can be firmly bonded to the fluororesin having.

[Example 1]
By an ordinary method, an inner rubber layer is formed on the outer peripheral surface of the wetted layer formed on the mandrel using an extruder, and a reinforcing thread is formed in a spiral structure on the outer peripheral surface of the inner rubber layer. After forming the reinforcing layer by braiding, an outer rubber layer was further formed using an extruder and vulcanized to produce a rubber hose of the present invention (inner diameter 9 mm) having the structure shown in FIG. The details of the vulcanization conditions and the hose are as follows.
<Vulcanization conditions>
Primary vulcanization: 160 ° C. × 45 minutes Secondary vulcanization: 160 ° C. × 4 hours <Material and dimensions of each part of rubber hose>
Material of wetted layer: Maleic anhydride modified ETFE “AH-2000”
Wetted layer thickness: 0.25mm
Material of inner rubber layer: maleic acid-modified HNBR “ZPT-136” (compound A)
Internal rubber layer thickness: 1.0mm
Reinforcing layer: PET fiber, 1100 dtex / 3 twist, number of driven 44, spiral braid, driving angle 50 °
Material of outer rubber layer: maleic acid-modified HNBR “ZPT-136” (compound A)
External rubber layer thickness: 0.5mm

[Comparative Example 1]
The inner rubber layer and outer rubber layer of Example 1 were prepared in the same manner as in Example 1 except that the blend A in Table 1 was changed to the blend E. The material and dimensions of each part of the produced rubber hose are as follows.
<Material and dimensions of each part of rubber hose>
Material of wetted layer: Maleic anhydride modified ETFE “AH-2000”
Wetted layer thickness: 0.25mm
Internal rubber layer material: Maleic acid-modified acrylic rubber “Vacac-G” (compound E)
Internal rubber layer thickness: 1.0mm
Reinforcing layer: PET fiber, 1100 dtex / 3 twist, number of driven 44, spiral braid, driving angle 50 °
Material of outer rubber layer: maleic acid-modified acrylic rubber “Vacac-G” (compound E)
External rubber layer thickness: 0.5mm

[Comparative Example 2]
It was produced in the same manner as above except that the liquid contact layer was removed from the configuration of Example 1. The material and dimensions of each part of the produced rubber hose are as follows.
<Material and dimensions of each part of rubber hose>
Material of inner rubber layer: maleic acid-modified HNBR “ZPT-136” (compound A)
Internal rubber layer thickness: 1.0mm
Reinforcing layer: PET fiber, 1100 dtex / 3 twist, number of driven 44, spiral braid, driving angle 50 °
Material of outer rubber layer: maleic acid-modified HNBR “ZPT-136” (compound A)
External rubber layer thickness: 0.5mm

[Comparative Example 3]
It was produced in the same manner as above except that the wetted layer was removed from the configuration of Comparative Example 1. The material and dimensions of each part of the produced rubber hose are as follows.
<Material and dimensions of each part of rubber hose>
Internal rubber layer material: Maleic acid-modified acrylic rubber “Vacac-G” (compound E)
Internal rubber layer thickness: 1.0mm
Reinforcing layer: PET fiber, 1100 dtex / 3 twist, number of driven 44, spiral braid, driving angle 50 °
Material of outer rubber layer: maleic acid-modified acrylic rubber “Vacac-G” (compound E)
External rubber layer thickness: 0.5mm

[Comparative Example 4]
Using a polybutene resin as the wetted layer, and a thermoplastic elastomer (TPE) as the inner rubber layer and outer rubber layer, each layer was formed by an extruder in the same manner as in Example 1, and the rubber hose (inner diameter) shown in FIG. 9 mm). The material and dimensions of each part of the produced rubber hose are as follows.
<Material and dimensions of each part of rubber hose>
Material of wetted layer: Polybutene resin "Byuron P5050"
Wetted layer thickness: 0.25mm
Material of inner rubber layer: TPE “Santplane 201-73”
Internal rubber layer thickness: 1.0mm
Reinforcing layer: PET fiber, 1100 dtex / 3 twist, number of driven 44, spiral braid, driving angle 50 °
Material of outer rubber layer: Styrene-based TPE “Dynalon 2324P”
External rubber layer thickness: 0.5mm

About the rubber hose produced above, it tested about the following items. The results are shown in Table 2.
"Evaluation method"
・ Adhesiveness (resin / rubber adhesiveness)
The rubber hose of Example 1 and Comparative Example 1 was cut to a length of about 20 cm, and the hose was halved using a fine cutter or the like in the longitudinal direction. Next, several cuts with a depth of about 0.5 mm were made in the longitudinal direction at intervals of about 3 mm with respect to the fluororesin (wetted layer) on the inner peripheral surface of the hose. Then, only the said fluororesin was peeled off using tools, such as pliers, the state with rubber | gum of this fluororesin was observed visually, and the following references | standards evaluated.
A: Surface area with rubber 90%
○: Surface area with rubber ratio 70% or more △: Surface area with rubber ratio 40% or more X: Surface area with rubber ratio less than 40% ・ Heat resistance After leaving the hose in an oven at 120 ° C. for 500 hours, residual elongation at break The rate was measured and evaluated according to the following criteria.
◎: Break elongation remaining rate of 80% or more ○: Break elongation remaining rate of 60% or more Δ: Break elongation remaining rate of 40% or more After leaving at 40 ° C. for 72 hours, the inner rubber layer was cut out, the volume swelling rate was measured, and evaluated according to the following criteria.
A: Volume swelling rate 0-20%
○: Volume swelling rate 21 to 40%
Δ: Volume swelling ratio 40 to 55%
X: Volume swelling ratio of 56% or more and chlorine-resistant aqueous solution In the hose cut to a length of 1 m, a chlorine concentration of 50 pphm, a temperature of 80 ° C., a flow rate of 0.3 L / min. The chlorine water was circulated under the above conditions, the time (days) until the hose leaked was measured, and evaluated according to the following criteria.
◎: 120 days or more ○: 90 to 119 days △: 60 to 89 days ×: 59 days or less ・ Hose flexibility The hose cut to a length of 50 mm is used as a three-point bending test jig with a distance between fulcrums (rollers) of 200 mm. Set the center of the hose with a load cell at 500 mm / min. And indentation load was measured and evaluated according to the following criteria.
◎: 20N or less ○: 21-28N
Δ: 29-35N
×: 36N or more

The details of the resin and rubber component in Table 2 are as follows.
Fluorine resin: manufactured by Asahi Glass Co., Ltd., maleic anhydride-modified ETFE “LM-ETFE-AH-2000” (having an acid anhydride group)
Polybutene resin: manufactured by Mitsui Chemicals, Inc., poly-1-butene resin “Bureon P5050”
TPE: “Santplane 201-73” manufactured by AES
Styrene TPE: “Dynalon 2324P” manufactured by JSR Corporation

  From the results of Table 2 above, it was confirmed that the rubber hose of the present invention (Example 1) was excellent in heat resistance, gasoline resistance (oil resistance), and chlorine water resistance (chemical resistance). In addition, since the wetted layer and the inner rubber layer are firmly bonded and have good flexibility, even if they are bent greatly due to external force applied during construction, they are not easily peeled off and have excellent durability. Is.

DESCRIPTION OF SYMBOLS 1 Rubber hose 2 Liquid contact layer 3 Inner surface rubber layer 4 Reinforcement layer 4a Braid layer 4b of metal fiber or reinforcement thread Organic fiber reinforcement layer 4c Hard metal reinforcement layer 5 Outer rubber layer

Claims (4)

In a fuel transport rubber hose comprising at least an inner rubber layer, a reinforcing layer formed outside the inner rubber layer, and an outer rubber layer formed outside the reinforcing layer,
A wetted layer made of a fluororesin is formed further inside the inner rubber layer, and the wetted layer is a fluororesin having a carboxyl group and / or an acid anhydride group, and the inner rubber layer is a carboxyl group and / or an acid anhydride group as a crosslinking site, acrylonitrile content of 20 to 50 wt%, and the hydrogenated acrylonitrile water hydride ratio is 95% or more - butadiene rubber (HNBR), consisting of a polyamine A rubber hose for fuel transportation , characterized in that the rubber hose is crosslinked with a crosslinking agent. The rubber hose for fuel transportation according to claim 1, wherein the fluororesin is a maleic anhydride-modified ethylene-tetrafluoroethylene copolymer (maleic anhydride-modified ETFE). 3. The rubber hose for fuel transportation according to claim 1, wherein the HNBR is modified with maleic acid or an anhydride thereof. The cross-linking agent is one or more cross-linking agents selected from diaminodiphenylmethane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane and hexamethylenediamine carbamate. The rubber hose for fuel transportation according to 1.

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