JPH08300524A - Resin tube for fuel piping - Google Patents

Abstract

PURPOSE: To prevent the interlayer separation of a tube by enhancing an adhesiveness between an inside layer consisting of fluororesin and an outside layer comprising resin having no good adhesiveness with fluororesin such as polyamide and polyester, etc. CONSTITUTION: The resin tube has two layers including at least an inside layer consisting of fluororesin comprised by appropriately applying a characteristics importing agent or additives and an outside layer consisting of polyamide resin or the like, wherein the surface of the inside layer being in contact with the outside layer is given an adhesive surface treatment.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a resin tube preferably used for fuel piping in a vehicle, and more particularly to a resin tube having a fluororesin layer and a resin layer such as a polyamide resin layer having poor adhesion to a fluororesin. The present invention relates to a resin tube for fuel piping having a laminated structure formed by stacking layers.

[0002]

BACKGROUND ART Conventionally, there are various materials for various piping tubes used in automobiles and the like. For example, tubes used for fuel piping and their connection are metal tubes. And resin tubes are used. In addition, metal tubes have the problem of rusting, and are very heavy, and cannot cope with the reduction of the weight of vehicles. It has been widely used, and a resin tube made of polyamide, polyester, or the like has been used.

However, since a single-layer tube made of a polyamide resin or the like has a high gasoline permeation amount and an inherent problem of environmental pollution, a fluorine-based tube having a high gasoline barrier performance is provided inside a resin layer of a polyamide or the like. It has been considered that a resin layer is applied to form a two-layer structure to reduce the gasoline permeation amount. However, due to the poor adhesion between the fluororesin and the resin such as polyamide, in such a tube, delamination may occur during use, and as a result, the tube may be blocked or gas may accumulate between the layers. It could burst.

[0004]

[Means for Solving the Problems] The present invention has been made against such a background, and the problem to be solved is to improve the adhesiveness between a fluorine-based resin layer and a resin layer such as polyamide. The purpose is to obtain a resin tube having a laminated structure that does not cause delamination.

[0005]

In order to solve the above-mentioned problems, in the present invention, an inner layer including a layer of a fluororesin, to which a property-imparting agent or an additive is appropriately added, and a polyamide, polyester, or the like. The fluororesin is a resin tube having at least two outer layers made of a resin having poor adhesiveness, and the surface of the inner layer in contact with the outer layer is subjected to an adhesive surface treatment. The subject is a resin tube for fuel piping.

Further, according to the present invention, an inner layer including a layer of a fluororesin, to which a property-imparting agent or an additive is appropriately added, and a resin such as polyamide or polyester having poor adhesiveness to the fluororesin are selected. A resin tube having at least two outer layers, and a surface of the inner layer in contact with the outer layer is subjected to an adhesive surface treatment, and a rubber, a thermoplastic resin, and a thermoplastic resin are provided on the outer side of the outer layer. A protective tube made of a material selected from the group consisting of elastomers, and also a resin tube for fuel piping, characterized in that it is further provided,
This is the summary.

According to one of the preferred embodiments of the present invention, a flame-retardant material is mixed with the material forming the protective layer to make the protective layer flame-retardant.

Further, according to the present invention, an inner layer including a layer of a fluororesin, to which a property-imparting agent or an additive is appropriately added, and a resin such as polyamide or polyester having poor adhesion to the fluororesin are selected. A resin tube having at least two outer layers, wherein the surface of the inner layer in contact with the outer layer is subjected to an adhesive surface treatment, and at least the inner surface portion of the inner layer is added by the addition of the property imparting agent. The subject is also a resin tube for fuel piping, which is characterized by being electrically conductive.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the resin tube according to the present invention, the fluorine-based resin forming the inner layer and the resin such as polyamide and polyester forming the outer layer are not special ones and are known in the art. Any of the various types can be used.

For example, as the fluorine-based resin, polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (CTFE), a copolymer of ethylene and tetrafluoroethylene (ETFE), ethylene and polychlorotrifluoroethylene are used. Copolymer of (ECTF
E), copolymers of hexafluoropropylene and tetrafluoroethylene (FEP), copolymers such as fluorinated alkoxyethylene resins (PFA), and various graft polymers and blends may be used.

As the polyamide resin, any known polyamide resin may be used regardless of whether it is an aliphatic type or an aromatic type, and a polymer of lactam, a condensate of diamine and dicarboxylic acid, a polymer of amino acid, And a copolymer thereof or a blend thereof, which is appropriately selected and used. Specific examples include nylon 6, nylon 66, nylon 610, nylon 612, nylon 11, nylon 12, and the like. Further, a polyester resin such as polybutylene terephthalate (PBT) can be used as a material for forming the outer layer.

If necessary, various known property-imparting agents and additives such as fillers such as glass fibers and metal powders, pigments, carbon black and the like may be added to the fluororesins and polyamides. It goes without saying that they are appropriately added. Further, the resin such as the fluorine-based resin and polyamide, respectively, using a commonly used twin-screw extruder or the like, after being uniformly kneaded under the melting temperature range, according to a normal tube extrusion operation. , Formed in a tubular body. Furthermore, in the case of forming a tubular body, a tube having a defined inner diameter can be formed by using a predetermined mandrel. It is also possible to perform molding without using a mandrel.

In the present invention, first, the inner layer is formed of a fluororesin and the surface (the surface in contact with the outer layer) is subjected to an adhesive surface treatment. As the adhesion surface treatment, various known methods such as a sodium treatment method, a flame treatment method, a corona discharge method, and a sputtering method can be performed. For example, the sodium treatment method is
The extruded inner layer is immersed in a chemical treatment solution containing a sodium-ammonia complex or a sodium-naphthalene complex to introduce an active group on its surface, then immersed in methanol, and further immersed in water, This is done by washing the surface of the inner layer and then drying. If necessary, an adhesive may be applied to the surface of the inner layer after the adhesion surface treatment.

Next, an outer layer is laminated on the outer side of the inner layer which has been subjected to such an adhesive surface treatment with a resin such as polyamide or polyester having a poor adhesiveness to the fluororesin. The thickness of the inner layer and the outer layer is to be appropriately determined depending on the application of the tube, for example, in a fuel pipe tube for an automobile,
The thickness of the inner layer is preferably about 0.05 mm to 0.5 mm, and the total thickness of the inner layer and the outer layer is preferably about 1.0 mm.

Thereafter, with the inner layer and the outer layer thus laminated, the tube is subjected to heat treatment, if necessary. In addition, as the heating temperature at that time, a temperature not lower than 150 ° C. and not higher than the melting point of the outer layer is adopted. This is because the effect of improving the adhesiveness becomes insufficient at a temperature lower than 150 ° C., and the tube softens at a temperature higher than the melting point of the resin forming the outer layer. . When the outer layer is made of polyamide resin, the melting point is about 2
The temperature is about 00 ° C to 210 ° C, but in actuality, the softening starts gradually from about 180 ° C. Therefore, although it has a relationship with the heating time, it is usually preferable that the heating temperature is about 180 ° C or less. In addition, the heat treatment time is appropriately determined according to the heating temperature, but usually exceeds 4 hours,
Since the effect cannot be further improved, it will be appropriately set within 4 hours or less.

The resin tube thus obtained is subjected to an adhesive surface treatment or, in addition thereto, a heat treatment, whereby the adhesiveness between the inner layer and the outer layer is extremely effectively enhanced. Therefore, delamination is unlikely to occur, bending work stability is high, and durability against vibration and bending is high. Furthermore, the accumulation of gas at the interface between the inner layer and the outer layer can be effectively prevented, and the rupture of the tube can be effectively prevented. Further, even when it is subjected to heat treatment, it can be carried out easily and inexpensively by itself. Therefore, by adding such heat treatment, the productivity of the resin tube is lowered, or the cost is significantly reduced. It will never rise.

It is desirable to provide a protective layer on the outer side of such a two-layer resin tube. Examples of the material for forming the resin tube include chloroprene rubber (CR) and ethylene-propylene. -Diene terpolymer rubber (EPDM), epichlorohydrin rubber (ECO), chlorinated polyethylene (CPE), acrylic rubber (ACM), chlorosulfonated polyethylene (CS)
M), rubbers such as silicone rubber (Q), thermoplastics such as vinyl chloride resin (PVC), and solids and foams such as thermoplastic elastomers. Also,
A mixture of these materials with a flame retardant material can also be used. The protective layer is usually 0.5 to 3 m after heat treatment of the resin tube having the two-layer structure.
The layers are laminated with a thickness of about m, and at that time, an adhesive may be applied between the protective layer and the resin tube, if necessary.

[0018]

EXAMPLES Some examples of the present invention will be shown below to clarify the present invention in more detail. However, the present invention is not limited by the description of such examples. Needless to say, it is not something to receive. Further, in addition to the following specific examples, in addition to the following embodiments, the present invention includes various modifications based on the knowledge of those skilled in the art without departing from the spirit of the present invention.
It should be understood that modifications, improvements, etc. may be made.

First, using various resin materials as shown in Table 1 below, an inner layer is molded by a usual extrusion molding method, and the surface thereof is treated with sodium according to a conventional method, and then an outer layer is laminated. Then, 15 types of tubes having a two-layer structure were molded. The inner diameter of the tube was 6 mmφ, the outer diameter was 8 mmφ, and the thickness of the inner layer was 0.3 mm and the thickness of the outer layer was 0.7 mm. Then, each tube was placed in an oven and heat-treated under the conditions shown in Table 1 below.

Then, a test piece having a width of 1 inch was taken from each of the tubes thus obtained, and JIS-K-63 was used.
According to the 180 degree peel test of 01, the peel strength is examined,
The results are shown in Table 1. The abbreviations in Table 1 are as follows. ETFE: Copolymer of ethylene and tetrafluoroethylene FEP: Copolymer of hexafluoropropylene and tetrafluoroethylene PFA: Fluorinated alkoxyethylene resin PA12: Nylon 12 PA11: Nylon 11 PBT: Polybutylene terephthalate

[0021]

[Table 1]

As is clear from the results of Table 1, the adhesive surface treatment on the inner layer enhances the adhesiveness between the inner layer and the outer layer, and further, in addition to such adhesive surface treatment, heat treatment is performed. By carrying out, the peel strength is effectively improved.

[0023]

As is apparent from the above description, in the resin tube according to the present invention, the inner layer made of the fluororesin and the polyamide, polyester, etc. can be obtained by performing the predetermined adhesive surface treatment. However, the adhesiveness between the fluorine-based resin and the outer layer made of a resin having poor adhesiveness can be effectively improved, and thus the adhesive layer has a remarkably high interlayer adhesiveness. Therefore, the resin tube is
Since the problem of delamination is advantageously solved, bending stability is improved, durability against vibration and bending is improved, and tube rupture due to gas accumulation at the interface between the inner and outer layers. Such concerns can be resolved.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B32B 27/36 B32B 27/36 31/12 7148-4F 31/12 31/26 7148-4F 31 / 26 F16L 11/04 F16L 11/04

Claims (4)

[Claims] 1. An inner layer including a layer of a fluororesin, to which a property-imparting agent or an additive is appropriately added, and an outer layer made of a resin such as polyamide or polyester, which has poor adhesion to the fluororesin. A resin tube for a fuel pipe, comprising a resin tube having at least two layers, and a surface of the inner layer in contact with the outer layer is subjected to an adhesive surface treatment. 2. An inner layer including a layer of a fluororesin, to which a property-imparting agent or an additive is appropriately added, and an outer layer made of a resin such as polyamide or polyester, which has poor adhesion to the fluororesin. A resin tube having at least two layers, wherein a surface of the inner layer in contact with the outer layer is subjected to an adhesive surface treatment, and a group consisting of rubber, a thermoplastic resin and a thermoplastic elastomer is provided on the outer side of the outer layer. A resin tube for a fuel pipe, further comprising a protective layer made of a material selected from the above. 3. The resin for a fuel pipe according to claim 2, wherein a flame-retardant material is mixed with a material forming the protective layer to make the protective layer flame-retardant. tube. 4. An inner layer including a layer of a fluororesin, to which a property-imparting agent or an additive is appropriately added, and an outer layer made of a resin such as polyamide or polyester, which has poor adhesion to the fluororesin. A resin tube having at least two layers, the surface of the inner layer in contact with the outer layer is subjected to an adhesive surface treatment, and by the addition of the property imparting agent,
A resin tube for fuel piping, wherein at least an inner surface portion of the inner layer is electrically conductive.