JPH04140589A - Resin tube for fuel piping - Google Patents

Abstract

PURPOSE:To improve the fuel barrier performance of a resin tube by forming the resin tube of a composition containing aromatic polyamide resin material and resin material, non-compatible with the aromatic polyamide resin material, as main components, and distributing the aromatic polyamide resin material at the rate of 10-70wt. parts to 100wt. parts of the sum quantity of both resin materials. CONSTITUTION:One layer of a single-layer tube or a multilayer tube is to be less than 2mm in thickness and formed of a composition containing aromatic polyamide resin material and resin material, non-compatible with the aromatic polyamide resin, as main components. The aromatic polyamide resin material is mixed at the rate of 10-70wt. parts to 100wt. parts of the sum quantity of both resin materials. One of these resin materials is distributed like bands in the matrix of the other resin material in such a way as to be expanded in the axial direction of the tube. Nylon 6, nylon 11, nylon 12 or the like is used as the resin material of low compatibility with the aromatic polyamide resin material. As a result, there is no fear of separation between layers while obtaining light weight and flexibility.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a resin tube for fuel piping, for example, a resin tube suitable for the fuel piping itself or for connecting the same, and in particular, to a resin tube with a thin single layer structure and a conventional resin tube. The present invention relates to a resin tube for fuel piping that exhibits excellent fuel barrier properties not only for gasoline fuel but also for mixed fuel containing methanol.

(Background Art) Conventionally, fuel piping tubes used in automobiles etc. as fuel piping itself or for connection thereto include:
Various performances are required, such as being lightweight, flexible, and having excellent fuel barrier properties (fuel impermeability).

In addition, in recent years, in preparation for the depletion of gasoline resources in the future, it has been considered to use a blended fuel containing gasoline and methanol. There is a growing demand for effective barrier properties against gasoline as well.

However, the metal tubes and rubber tubes currently commonly used for fuel piping cannot satisfy all of their performance requirements, and they all have some problems. There are seven.

In other words, metal tubes have extremely high fuel barrier properties against both gasoline and methanol-blended gasoline, but because of their uniform flexibility, they cannot be bent freely when piping. In addition to making piping difficult, there is also a problem that compatibility with nipples and the like cannot be obtained, which necessitates the use of rubber joints and the like, making piping even more troublesome.

Furthermore, it has the problem of being quite heavy and causing mackerel.

On the other hand, rubber tubes have high flexibility and provide good sealing properties with nipples, etc., but they have a problem of insufficient fuel barrier properties.

Therefore, it is usually formed as a multilayered tube made by laminating fluorocarbon rubber, etc., which has high fuel barrier properties, and has good fuel barrier properties against both ordinary gasoline and methanol-blended gasoline. It is designed to be prepared. However, such a multi-layered rubber tube has the potential for peeling between the eyebrows, so it is necessary to always consider adhesive strength. There was also the problem of increased weight.

In contrast, in recent years, polyamide resins such as nylon 6 and nylon 12 4, which are lighter and more flexible than metal tubes and have good fuel barrier properties against gasoline, have been used as molding materials to create single-layer resin tubes. Various studies have been made to use tubes for fuel piping. Since such resin tubes have a considerably low barrier property against methanol-containing gasoline, there is a strong desire for improvement in this respect when considering future practicality.

(Problem to be solved) Against this background, the present invention has been made, and the problem to be solved is to further improve the fuel barrier properties of resin tubes, thereby making them useful in the future. An object of the present invention is to provide a resin tube for fuel piping.

(Solution Means) In order to solve the above problems, in the present invention, at least one layer of the single-layer tube or the multi-layer tube is made of an aromatic polyamide resin material in a layer thickness not exceeding 2 ma+. It is formed from a composition whose main component is another resin material that is incompatible with the aromatic polyamide resin material, and 10 of the total amount of both resin materials.
0 parts by weight, the aromatic polyamide resin material contains 1
The resin material is contained in a proportion of 0 to 70 parts by weight, and one of these resin materials is distributed in a band-like or streak-like manner in a matrix made of the other resin material so as to extend in the axial direction of the tube. The gist thereof is a resin tube for fuel piping characterized by the following.

(Specific structure/effect) In short, in the present invention, a predetermined resin composition containing as main components an aromatic polyamide resin material and another resin material that is incompatible with the aromatic polyamide resin material is prepared. The desired resin tube is formed using the composition.

By the way, the aromatic polyamide resin material which is one of the main components of the resin composition used in the present invention is as follows:
It is a polyamide resin having an aromatic ring in its molecular chain, and is obtained by combining at least one monomer having an aromatic ring as a heptamer to provide the polyamide resin. This resin material has extremely high fuel barrier properties, especially against methanol-containing gasoline, but on the other hand, it has the inherent problem of high rigidity and poor flexibility. There is.

Specifically, such aromatic polyamide resin materials are obtained by polycondensation of aromatic dicarboxylic acids and aliphatic diamines, polycondensation of aliphatic dicarboxylic acids and aromatic diamines, or copolymerization thereof. Furthermore, in the present invention, a blend of such aromatic polyamides can also be used. To give specific examples of these monomers, the aromatic dicarboxylic acid is:
Terephthalic acid, isophthalic acid, phthalic acid, etc. can be used, and xylylene diamine etc. can be used as the aromatic diamine.

The aliphatic dicarboxylic acids include malonic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, undecanniic acid, dodecanionic acid, tridecanionic acid, tetradecanionic acid, hexadecandioic acid, hexadecendioic acid, octadecandioic acid, Examples of the aliphatic diamines include octadecenniic acid, eicosaniic acid, and eicosenniic acid. Decamethylene diamine, undecamethylene diamine, dodecamethylene diamine, tridecamethylene diamine, hexadecamethylene diamine, octadecamethylene diamine, 2. ．． 2.
Examples include 4 (or 2.4°4)-trimethylhexamethylene diamine.

By the way, in the present invention, another resin material that is incompatible with the aromatic polyamide resin material is blended as another main component of the composition. In short, the composition is prepared as a blend of these mutually incompatible resin materials, and generally the aromatic polyamide resin material is dispersed in the other resin material as a matrix. However, if the blended amount of the aromatic polyamide resin material is large, using the aromatic polyamide resin material as a matrix,
A composition is obtained in which the other resin material is dispersed.

The other resin material to be blended with this aromatic polyamide resin material may be one that has low compatibility with the aromatic polyamide resin material to the extent that the prepared composition is in a dispersed state. , any of them can be employed, specifically nylon 6, nylon 11, nylon 12, nylon 612, nylon 11, or nylon 12 and nylon 66.
Aliphatic polyamide resin such as a blend of No. 6, EVO
Examples include resin materials such as H (hydrolyzate of ethylene-vinyl acetate copolymer) and maleic acid-modified EPDM.

In addition, the blending ratio of the aromatic polyamide resin material and the other resin materials is determined appropriately depending on the type of resin material used, but the composition is prepared as a uniform dispersion system. 10 to 70 parts by weight of the aromatic polyamide resin material per 100 parts by weight of the total amount of both resin materials so that good fuel barrier properties can be obtained and flexibility can be improved. It will be blended in the ratio of That is, if the amount of the aromatic polyamide resin material is less than 10 parts by weight, the effect of improving the barrier properties against methanol-containing gasoline will be insufficient, and if the amount exceeds 70 parts by weight. This is because the composition becomes extremely rigid and lacks flexibility.

In addition, these two resin materials are mixed uniformly in the melting temperature range using a normal two-wheel screw extruder, etc. to prepare a tube forming material. There is no problem in adding various property-imparting agents and additives as appropriate.

Then, by molding a tube using the resin composition thus prepared according to a normal tube extrusion method, the desired resin tube for fuel piping can be obtained.

That is, by tube extrusion molding the composition,
The particles of the other resin material dispersed in one resin material extend in the axial direction of the tube in a band or stripe shape, so the formed tube has a structure as shown in Figure 1, for example. As a result, the aromatic polyamide resin material with high fuel barrier properties is distributed in multiple layers in the tube thickness direction, whether it constitutes the matrix or the dispersed particles. It is. In FIG. 1, 2 is an aromatic polyamide resin material formed into a band or stripe shape by tube extrusion, and 4 is an aromatic polyamide resin material that is incompatible with the aromatic polyamide resin material. The resin material constitutes a matrix for the aromatic tetraamide resin material.

Therefore, by having such a characteristic structure, the resin tube according to the present invention exhibits extremely high fuel barrier properties even if the tube wall thickness is as thin as about 1 m. If the wall thickness exceeds 2 m, the fuel barrier properties will deteriorate. Therefore, in the present invention, the layer thickness of the tube formed from the composition must not exceed 2 m.

In the present invention, such a thin walled resin tube can be used as a product as it is, but such a resin tube can also be applied as one layer of a multilayered tube. For example, in a tube with a two-layer structure consisting of a base tube and a protective layer on the outside thereof, the base tube is formed of the above-mentioned composition, while the protective layer is formed of a predetermined rubber material, soft resin, thermoplastic elastomer, etc. It may also be formed by

(Examples) Below, some examples of the present invention will be shown to clarify the present invention more specifically, but the present invention is not limited in any way by the description of such examples. Needless to say, it is not something that can be accepted.

In addition to the following examples and the above-mentioned specific description, the present invention includes various changes, modifications, and changes based on the knowledge of those skilled in the art, as long as they do not depart from the spirit of the present invention. It should be understood that improvements and the like may be made.

First, various compositions were prepared with the formulation shown in Table 1 below, and from each composition, a single-layer resin tube with an inner diameter of 6 mm was produced according to a normal tube extrusion method. . The abbreviations in the table are as follows.

I Nitrimethyl Polycondensate of hexamethylene diamine and terephthalic acid ■: Polycondensate of hexamethylene diamine and terephthalic acid PA6: Nylon 6 PA12: Nylon 12 PA612: Nylon 612 PA Prene F: 50 of nylon 12 and nylon 666
: 50 (volume %) Blend EVOH: Hydrolyzate of ethylene-vinyl acetate copolymer EPDM': Maleic acid-modified EPDM Then, the flexibility and fuel barrier properties of the obtained various tubes were evaluated by the method shown below. The results were shown in Table 1 below.

Chi': Double layer 111 Cut each tube into 300 lengths, diameter: 60■φ
We measured the load when winding it around the mandrel. The results are shown as relative values, with the flexibility value of the tube of NQ12 set as 1.

The punishment is 50% of test gasoline or test gasoline and methanol.
One of the mixed gasolines mixed at a ratio of 0:50 (volume %) was sealed in each tube, left at a temperature of 40°C, and the amount of weight loss (g/day) was measured. It was measured.

As is clear from the results shown in Table 1, the layer thickness is 1+m++ or 0.
．． The tubes of Nα1 to Nα11 formed with a thickness of 5 mm all have good flexibility comparable to the tubes of M and 12, which are comparative examples, and have extremely effective fuel barrier properties against methanol-blended gasoline. This has been improved.

On the other hand, tubes made of only aliphatic polyamide resin material (No. 12) and tubes made of compositions containing aromatic polyamide resin material but with a small amount (No. 13) , the barrier properties against methanol-containing gasoline are extremely poor, and tubes made only of aromatic polyamide resin materials (N
o, 14), the flexibility of the tube is extremely poor.

Although tubes made of the composition according to the present invention have a layer thickness of more than 21II11 (Nα15, 16), the fuel barrier properties deteriorate and the flexibility also decreases.

(Effects of the Invention) As is clear from the above explanation, the resin tube according to the present invention achieves extremely excellent fuel barrier properties in a layer structure with a layer thickness not exceeding 2 am. There is no fear of this, and it is also lightweight and flexible, making it extremely useful as a tube for fuel piping.

Therefore, such resin tubes can be suitably used as fuel piping tubes for automobiles, etc., and can advantageously reduce the weight of the product, facilitate piping work, and improve the sealing properties of joints. Furthermore, it has good fuel barrier properties not only against gasoline but also against methanol-mixed gasoline, so it will have high utility value in the future.

[Brief explanation of drawings]

FIG. 1 is a partially cross-sectional explanatory diagram schematically showing the structure of a resin tube according to the present invention. 2: Aromatic polyamide resin material 4: Other resin materials

Claims (1)

[Claims] At least one layer of the single-layer tube or the multi-layer tube is mainly composed of an aromatic polyamide resin material and another resin material that is incompatible with the aromatic polyamide resin material, with a layer thickness not exceeding 2 mm. 10 to 10 parts by weight of the aromatic polyamide resin material per 100 parts by weight of the total amount of both resin materials.
The resin material is contained in a proportion of 70 parts by weight, and one of these resin materials is distributed in a band-like or streak-like manner in a matrix made of the other resin material so as to extend in the axial direction of the tube. Resin tube for fuel piping.