JP3166495B2 - Laminated hose - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hose having a structure in which a resin inner layer is laminated on the inner peripheral surface of a rubbery outer layer, and more particularly to a fuel hose for automobiles having high gasoline resistance and low gasoline permeability. Filler hose) and the like.

[0002]

2. Description of the Related Art In recent years, it has been necessary to reduce the amount of hydrocarbons released into the atmosphere in connection with air pollution, so that regulations regarding the permeation amount of hydrocarbons (gasoline) have become strict even for fuel hoses of automobiles. ing.

[0003] Fuel hoses, that is, hoses (filler hoses, filler neck hoses) connecting a fuel tank of an automobile and an inlet for injecting gasoline, are conventionally made of a rubber material having fuel oil resistance and weather resistance. For example, a single layer structure of acrylonitrile butadiene rubber (NBR) / polyvinyl chloride (PVC) blend rubber, or an inner layer of NBR, an outer layer of chloroprene rubber (CR), chlorosulfonated polyethylene rubber (CSM), epichlorohydrin rubber (CHC), etc. Although those having a two-layer structure are used, the current situation is that fuel hoses having these structures cannot fully comply with the above regulations. Particularly recently, alcohol-added gasoline in which alcohol is added to gasoline has been used to purify automobile exhaust gas, and the added gasoline has higher permeability than non-added gasoline. An excellent fuel hose is required.

In order to reduce gasoline permeation, it is necessary to use a material having low permeability as much as possible. Since metallic materials do not substantially permeate gasoline, it is preferable in this respect. When considering the action, it is often difficult in practice to use a material having an extremely high elastic modulus, such as a metal. Therefore, usually, an elastic (flexible) material such as resin or rubber is used. The gasoline permeability is selected as small as possible.

[0005] However, resin materials generally have a low elasticity compared to rubber, and therefore have a drawback in flexibility when used as a fuel hose. Specifically, a fuel hose made of resin cannot absorb an error generated between a fuel tank and a vehicle body when assembled to an automobile, and also has a problem in fitting property with a metal part to be assembled.

On the other hand, those using a rubber material or the like include:
A hose having a structure of two or more layers using a fluorine-based rubber as an innermost layer and using an NBR / PVC blended rubber, CR, CSM or the like as an outer layer is known. Fluorine-based rubber shows extremely low gasoline permeability compared to other rubber materials by containing fluorine in its molecular skeleton, and its elasticity is equivalent to other rubber materials. The fuel hose has the advantage that the permeability to gasoline can be greatly reduced as compared with the conventional one, while maintaining the same connection function as that formed by the conventional rubber material.

[0007] However, fluorine-based rubber has a limitation due to a high unit price of the material, though the permeability to gasoline is reduced when the thickness is increased, and it is rather an issue of industrial production to make the rubber as thin as possible. There are cost constraints. Particularly, when a hose having a laminated structure is manufactured by extrusion molding, the thickness of the inner layer cannot be reduced significantly with the performance of the current extruder, and the cost is inevitable.
In addition, since a fluorine-based resin is generally non-adhesive, it is difficult to laminate the rubber-based outer layer with the rubber-based outer layer. To compound the rubber layer and the fluorine-based resin layer, means such as interposing an adhesive layer is required. There is a problem that the process becomes complicated.

[0008]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned problems in the conventional laminated hose, and an object of the present invention is to provide a fuel hose having low gasoline permeability, excellent flexibility, and low cost.

[0009]

According to the present invention, there is provided a laminated hose having the following constitution. (1) A laminated hose having a thin resin inner layer laminated on the inner peripheral surface of a rubber outer layer, wherein the resin inner layer has
A mixture of a fluorine-based thermoplastic resin powder and a polyamide-based thermoplastic resin powder is powder-coated on the inner peripheral surface of the rubber outer layer, and the fluorine-based thermoplastic resin and polyamide formed by heating and melting the mixture. A laminated hose comprising a mixture with a thermoplastic resin. (2) The interlayer adhesion between the resin inner layer and the rubber outer layer is 2 N / mm
The hose having the above-mentioned structure (1), wherein the gasoline permeability is 6.0 mg / cm ² · day or less. (3) The laminated hose according to the above (1), wherein the resin inner layer comprises 10 to 40% by weight of a fluorine-based thermoplastic resin and 90 to 60% by weight of an amide-based thermoplastic resin. (4) The rubber outer layer is preformed in a vulcanized or semi-vulcanized state, and the charged mixture powder is electrostatically coated on the inner side of the rubber outer layer. The laminated structure hose according to claim 1, wherein the mixture powder is heated and melted by heating the mixture powder or by inserting a rod-shaped heating device inside the rubber outer layer and heating from the inside.

[0010]

DETAILED DESCRIPTION OF THE INVENTION As the rubber material forming the outer layer of the laminated hose according to the present invention, a material having flexibility and weather resistance is used, and the rubber material of the conventional single-layer hose or the conventional laminated hose is used. A material similar to the rubber material forming the outer layer can be appropriately selected and used. Preferred rubber materials include, for example, halogen-containing rubbers such as NBR / PVC blend rubbers, CR, CHC, and CSM. Depending on the application, ethylene-propylene-non-conjugated diene copolymer rubber (EPDM) is used. You can also.

The inner layer of the laminated hose according to the present invention is formed of a resin comprising a mixture of a fluorine-based thermoplastic resin and a polyamide-based thermoplastic resin. Both the fluorine-based thermoplastic resin and the polyamide-based thermoplastic resin have low permeability to gasoline, and in particular, the fluorine-based thermoplastic resin has excellent permeability resistance to alcohol-added gasoline. The gasoline permeability is determined by the gasoline permeation constant of the resin. The permeation constant was obtained by putting gasoline in a container, contacting the liquid surface, closing the resin film, measuring the weight loss after a certain period of time in a sealed state, and expressing this as a value per unit area. Things. Specifically, after a lapse of 24 hours at a temperature of 40 ° C., it is expressed as a weight reduction (mg · mm / cm ² · day) per 1 cm ^{2 of} a resin film and 1 cm ^{2 of} a surface area. Refers to one or less. Polyamide resins generally have a gasoline permeation constant of 1 or less, and fluorine resin generally has a smaller gasoline permeation constant. Therefore, gasoline permeability can be significantly reduced by using a mixture of a fluorine-based resin and a polyamide-based resin.

When alcohol is added to gasoline, the gasoline permeation constant of the resin changes, and the permeation constant of the polyamide-based resin is slightly increased. However, this change is small for the fluorine-based resin. Therefore, the resin inner layer made of a mixture of the fluorine-based resin and the polyamide-based resin of the present invention exhibits excellent low permeability to alcohol-added gasoline.

Next, it is generally difficult to laminate the fluororesin with the outer rubber layer because the fluororesin is generally non-adhesive. However, in the present invention, the fluororesin is mixed with a polyamide resin having excellent adhesive strength. By using this, the interlayer bonding strength between the resin inner layer and the rubber outer layer was greatly increased. Specifically, as an example, a mixture of a fluorine-based resin powder and a polyamide-based resin powder is powder-coated on the inner peripheral surface of the rubber outer layer, and this is heated and melted to thereby cover the inner peripheral surface of the hose. The powder is firmly adhered to the inner peripheral surface by the molten polyamide-based resin, and a resin inner layer having high interlayer bonding strength is formed on the inner peripheral surface of the rubber outer layer. If such powder coating is used, a resin inner layer having a small layer thickness can be formed unlike conventional extrusion molding.

The fluorine-based thermoplastic resin and the polyamide-based thermoplastic resin used in the present invention may be any fuel hose that satisfies the above gasoline permeability and adhesiveness as a fuel hose. Preferred is a material which can be easily formed into powder and can be formed into a melt at a temperature of about 200 ° C. or lower. If the melting temperature of the resin exceeds 200 ° C., the heat during the heating and melting may undesirably cause the physical properties of the rubbery outer layer to decrease.

Preferred examples of such a fluorine-based thermoplastic resin include, for example, polyvinylidene fluoride (PVD).
F) or a binary or terpolymer of vinylidene fluoride and tetrafluoroethylene or hexafluoropropylene. Preferred examples of the polyamide thermoplastic resin include 11-nylon, 12-nylon, and 6-nylon. 66 copolymer nylon, 6-12 copolymer nylon, 6-610-12 copolymer nylon, 6-66-12
Copolymer nylon and N-methoxymethyl-6-nylon are exemplified.

The particle size of each of the above resin powders is 200 μm or less,
Further, the thickness is preferably 100 μm or less. When a resin powder having a particle size of more than 200 μm is used, each resin is not well dispersed, and it is difficult to obtain a satisfactory effect on gasoline permeability and adhesiveness.

The content of each of the above resins is such that the fluorine-based thermoplastic resin is 10 to 40% by weight, preferably 15 to 3% by weight.
0% by weight, and 90 to 60% by weight, preferably 85 to 70% by weight of the polyamide-based thermoplastic resin. If the proportion of the fluorine-based resin exceeds 40% by weight, the amount of the polyamide-based resin is relatively reduced, so that the adhesiveness between the resin inner layer and the rubber outer layer is reduced.
On the other hand, if the proportion of the fluororesin is less than 10% by weight, the effect of suppressing permeation of alcohol-added gasoline is undesirably reduced.

The outer layer rubber and the inner layer resin material of the hose of the present invention may contain an antioxidant, a neutralizing agent, a nucleating agent, an epoxy stabilizer, an antistatic agent (an interface) as long as the effects of the present invention are not impaired. Other additives such as an activator, a plasticizer, an antibacterial agent, and a flame retardant may be appropriately added as necessary.

[0019]

[Production Method] The laminated hose having a thin resin inner layer of the present invention can be produced by applying a resin powder mixture to the inner peripheral surface of the rubbery outer layer and then heating and melting the mixture as described above. (See Japanese Patent Application No. 5-336091).

That is, the rubbery outer layer is first preliminarily formed into a vulcanized or semi-vulcanized state by injection molding or the like using a molding die composed of an outer die and an inner die. Next, a mixed powder of a fluorine-based resin and a polyamide-based resin is powder-coated on the inside of the rubber outer layer. Specifically, air and resin powder are supplied to the spray gun connected to the high voltage generator through an air pipe and a resin powder supply pipe, and negative or positive is supplied from a long nozzle attached to the spray gun. The electrostatically sprayed resin powder is ejected to perform electrostatic coating.

After coating, the resin powder is heated and melted to form a thin film. When a semi-vulcanized rubber outer layer is used, vulcanization is completed by this heating. As a heating method, for example, a method in which a rubber outer layer whose inside is coated with a resin powder is put into a heating oven and heated as a whole, or a method in which a rod-shaped heating device is inserted inside the rubber outer layer and heating is performed from the inside Can be implemented.

[0022]

[0023]

EXAMPLES Examples of the present invention will be described below together with comparative examples, but these examples are illustrative and do not limit the scope of the present invention. The raw materials used in this example and comparative examples are as shown in Table 1.

[0024]

[Table 1] Rubber for outer layer (1) BR / PVC (2) Resin melting point for CHC inner layer (° C) Powder particle size (μm) (1) Nylon 11 non-plastic (PA11) 186 30 (2) PVDF homopolymer 170 4 (3) PVDF polytetrafluoroethylene copolymer (PVDF / PTFE) 126 4

Example 1 A single-layer rubber tube having an inner diameter of 36 mm, a thickness of 4 mm and a length of 250 mm was formed by vulcanization molding using NBR / PVC as a rubber material for the outer layer. Vulcanization was performed at 160 ° C. for 5 minutes.
Next, a mixed powder of PA11 and PDVF (PA11: PDVF = 85: 15 weight ratio) was spray-coated on the inner peripheral surface of the rubber tube with an electrostatic coating machine (manufactured by Ransberg), and the sample was applied. 225
The resin was put into an oven heated to 0 ° C. and allowed to stand in that state for 15 minutes to melt the resin, thereby forming a resin layer having a thickness of 0.2 mm. After confirming that a uniform resin layer was formed on the inner surface, the following physical properties were measured. Table 2 shows the results.

(A) Adhesive force between rubbery outer layer and resin inner layer A strip-shaped sample having a width of 25 mm from the normal direction of the sample was collected and JISK
The adhesive force between the rubber outer layer and the resin inner layer was measured according to the method of 6301. The results are shown in Table 2. (B) Gasoline and alcohol-added gasoline permeability Connect one opening of the sample hose to the gasoline tank,
The other opening was closed with a metallic lid, and left in a constant temperature bath at 40 ° C. with gasoline in contact with the inner wall of the sample.
The weight loss after 24 hours was measured. Similarly, the weight loss of gasoline containing 15% of methanol was measured. The results are shown in Table 2.

Examples 2 to 4 and Comparative Examples 1 and 2 Example 1 was conducted using the rubber for the outer layer and the resin for the inner layer shown in Table 2.
A hose was manufactured in the same manner as described above, and each physical property was measured. The results are summarized in Table 2.

[0028]

[Table 2]

As is apparent from Table 2, the hose having a layer made of only a polyamide resin inside the rubber outer layer (Comparative Example 1) has good adhesive strength between layers and resistance to gasoline permeation, but alcohol-added gasoline. In the case of a hose in which a layer made of only a fluorine resin is provided inside the rubber outer layer (Comparative Example 2), there is no adhesive force between the layers, so that the laminated structure cannot be maintained. It turns out that it cannot withstand. On the other hand, the hose of the present invention (Examples 1 to 4) has a large interlayer adhesive strength and also has excellent permeation resistance to gasoline and alcohol-added gasoline. In addition, when the cross section of the resin layer of the hose obtained in Example 1 was observed with a reflection electron microscope (manufactured by Hitachi, Ltd.), as shown in FIG. It is considered that the resin 11 is well dispersed, and therefore, this layer configuration provides a large interlayer adhesion to the rubber outer layer 13 and further develops more excellent gasoline permeation resistance.

[0030]

The laminated hose according to the present invention is obtained by laminating a resin thin film made of a fluorine-based thermoplastic resin and a polyamide-based thermoplastic resin on the inner surface of a rubber outer layer.
Excellent interlayer adhesion between the rubbery outer layer and the resin inner layer is achieved by the polyamide resin, and high permeation resistance to gasoline and alcohol-added gasoline is obtained by the fluororesin. In addition, if manufactured by the electrostatic coating method, a thin resin inner layer can be formed, which is excellent in cost performance. Further, the flexibility of the entire hose is maintained, so that it can be fitted to a fuel tank or an inlet. Is also good.

[Brief description of the drawings]

FIG. 1 is an electron micrograph of a cross section of a resin layer of a hose obtained in Example 1.

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B32B 1/00-35/00 F16L 9/00-9/22 F16L 11/00-11/24

Claims (4)

(57) [Claims] 1. A laminated hose having a thin resin inner layer laminated on an inner peripheral surface of a rubber outer layer, wherein the resin inner layer has a fluorine-based thermoplastic resin powder on an inner peripheral surface of the rubber outer layer. A laminate comprising a mixture of a fluorine-based thermoplastic resin and a polyamide-based thermoplastic resin formed by powder-coating a mixture with a polyamide-based thermoplastic resin powder and heating and melting the mixture. Structural hose. 2. The interlayer adhesion between the resin inner layer and the rubbery outer layer is 2
The laminated hose according to claim 1, wherein the hose has a gasoline permeability of 6.0 mg / cm ² · day or less. 3. The resin inner layer is made of a fluorine-based thermoplastic resin
2. The laminated hose according to claim 1, comprising 40% by weight and 90 to 60% by weight of an amide-based thermoplastic resin. 4. The rubber outer layer is preformed in a vulcanized or semi-vulcanized state, a charged mixture powder is electrostatically coated on the inside of the rubber outer layer, and then the rubber outer layer is placed in a heating oven. The laminated hose according to claim 1, wherein the mixture powder is heated and melted by heating as a whole or by inserting a rod-shaped heating device inside the rubber outer layer and heating from the inside.