JP2005180567A - Resin-made tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that a conventional resin-made tube is poor in mountability on a pipe and requires high cost due to a large number of parts items in connection. <P>SOLUTION: The resin-made tube 11 is equipped with a laminated tube 12 in which the innermost layer 12a is made up of thermoplastic resin having hardness of 90 or less and the outermost layer 12b is made up of a thermoplastic resin having a tension elastic modulus of 30MPa or more, a pipe body 13 for coupling is made up of a thermoplastic resin containing 50 wt.% or more of a forming material of the innermost layer 12a. While at least the innermost layer 12a of the laminated tube 12 and the pipe body 13 for coupling are coupled by fusing, each inside surfaces of the laminated tube 12 and the pipe body 13 are continued in a substantially coplanar manner. While mountability to mating member such as pipe is improved without deteriorating essential advantages, a total cost reduction is materialized. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a resin tube used in various distribution systems such as a fuel system, an air system, and a cooling system of an automobile.

Generally, metal, rubber and resin tubes, or tubes using two or three of these materials are used in distribution systems such as automobile fuel systems, air systems and cooling systems. . FIG. 5 is a diagram showing a connection structure between a pipe 101 and a rubber tube 102 provided in a structure such as a tank. The rubber tube 102 is fitted to the outside of the pipe 101, and the outer periphery of this fitting portion is shown. It is tightened by a belt-like clamp 103 that can be adjusted in length.
In recent years, resin tubes are becoming mainstream due to advantages such as no rust, light weight and low cost. FIG. 6 is a view showing a connection structure between the pipe 201 and the resin tube 202, and uses a tubular connector 203. An O-ring 204, a backup ring 205, and a spacer 206 are provided inside one end of the connector 203. The pipe 201 is fitted through the connector 23, and the resin tube 202 is fitted through the O-ring 207 outside the other end of the connector 23.

  However, in the case of the resin tube as described above, the rigidity is higher than that of the rubber tube, so that the assembly property to the pipe is poor, and it is difficult to obtain the sealing property of the connecting portion. In addition to the connector shown, a plurality of sealing parts such as an O-ring, a backup ring, and a spacer are indispensable, which increases the cost. Furthermore, since a connector is used, it may be necessary to review the shape of the mating member such as a pipe corresponding to this connector, which may require a significant change in the mold for molding the mating member. .

  The present invention has been made in view of the above-described conventional situation, and aims to solve the conventional problems without impairing the advantages of the resin tube.

  The resin tube of the present invention has at least two resin layers concentrically laminated, and the innermost layer is made of a thermoplastic resin having a hardness of 90 or less, and at least one of the layers other than the innermost layer has a tensile elastic modulus. A laminated tube made of a thermoplastic resin of 30 MPa or more and a connecting tube made of a thermoplastic resin containing 50% by mass or more of the material forming the innermost layer of the laminated tube are provided. Then, with the end portion of the laminated tube expanded, at least the innermost layer of the laminated tube and the connecting tube are connected by fusion, and the inner surface of the laminated tube and the inner surface of the connecting tube are substantially flush with each other. It is characterized by being continuous.

  In addition, as a preferable manufacturing method, the above-mentioned resin tube is formed by injection-molding a connecting tube with the end portion of the laminated tube inserted into a mold, and at least the innermost layer of the laminated tube and the connecting tube The manufacturing method which fuse | melts is mentioned.

  Further, the above-mentioned resin tube has, for example, a connection structure suitable for a cooling water circulation system of an automobile, the innermost layer of the laminated tube and the material of the connection tube are made of an olefin thermoplastic elastomer, and the connection tube is a pipe. A connection structure in which the outer periphery of the mating member of the connecting member is fastened with a clamp is used.

  According to the resin tube of the present invention, since it is composed of a laminated tube and a connecting tube, there is no generation of rust, and the original advantage of being able to be reduced in weight and being low in cost is lost. It is possible to further reduce the weight by thin wall, and it is easy to assemble to a mating member such as a pipe, no connectors are required, and the sealing property of the connecting part with the mating member is also good. Therefore, the number of sealing parts can be reduced, and the total cost can be reduced. Furthermore, the flow resistance of the internal fluid can be kept small by making the inner surfaces of the laminated tube and the connecting tube body substantially continuous.

  According to the method for producing a resin tube of the present invention, it is possible to efficiently mass-produce a resin tube composed of a laminated tube and a connecting tube, and to provide a resin tube having no variation in quality. .

  According to the connection structure of the resin tube of the present invention, it is suitable for, for example, a cooling water circulation system of an automobile, and in the innermost layer of the laminated tube and the connecting pipe body, heat resistance, hydrolyzability, and a barrier against cooling water Therefore, it is possible to obtain a connection structure with very little deterioration in quality over a long period of time.

  FIG. 1 is a view showing an embodiment of the resin tube of the present invention. The illustrated resin tube 11 includes a laminated tube 12 in which at least two or more resin layers are concentrically stacked, and a connecting tube 13 that constitutes an end of the resin tube 11.

  The illustrated laminated tube 12 has two resin layers. The innermost layer 12a is made of a thermoplastic resin having a hardness (rubber hardness) of 90 or less, and at least one of the layers other than the innermost layer 12a, that is, the illustrated example. Then, the outermost layer 12b is made of a thermoplastic resin having a tensile elastic modulus of 30 MPa or more. On the other hand, the connecting tube 13 is made of a thermoplastic resin containing 50% by mass or more of the material forming the innermost layer 12a of the laminated tube 12.

  Then, the resin tube 11 is connected to at least the innermost layer 12a of the laminated tube 12 and the connecting tube 13 by fusion, with the end portion of the laminated tube 12 being expanded, and connected to the inner surface of the laminated tube 12. The inner surface of the pipe body 13 is made to be substantially the same plane.

  Here, the hardness of the innermost layer 12a of the laminated tube 12 is set to 90 or less. When the hardness exceeds 90, the flexibility of the resin tube 11 itself and the fusing property with the connecting tube 13 are lowered. This is because the tensile elastic modulus of the outermost layer 12b of the laminated tube 12 is set to 30 MPa or more because the mechanical strength of the resin tube 11 itself decreases when the tensile elastic modulus is less than 30 MPa. It is.

  Furthermore, the material for forming the innermost layer 12a included in the connecting tube 13 is 50% by mass or more, while ensuring good assembling and sealing properties with respect to a mating member such as a pipe, and the connecting tube 13 This is for obtaining a sufficient fusion strength between the innermost layer 12a and the innermost layer 12a. This fusion strength can be ensured at a minimum if the material for forming the innermost layer 12a contained in the connecting tube 13 is 30% by mass or more, but it is 60% by mass or more from the viewpoint of low transmission. Is desirably 80% by mass or more, and more desirably 100% by mass.

  The resin tube 11 having the above-described configuration is fitted with a mating member such as a pipe without causing any rust, reducing the weight and reducing the low cost of the resin tube. Assembling performance is good, the conventional connector (see Fig. 6) is unnecessary, and the sealing performance of the connecting part with the mating member is also good, so the number of sealing parts can be reduced or eliminated. And the total cost can be reduced. Furthermore, since the inner surfaces of the laminated tube 12 and the connecting tube 13 are made to be substantially the same surface, the flow resistance of the internal fluid can be kept small.

  Further, the resin tube 11 can be composed of the innermost layer 12a of the laminated tube 12 and the connecting tube body 13 made of the same material, and at this time, both can be made of a thermoplastic resin having a hardness of 80 or less. By doing so, the fusion strength between the laminated tube 12 and the connecting tube 13 becomes stronger.

  Furthermore, in order to manufacture the resin tube 11, the connecting tube 13 is injection-molded with the end portion of the laminated tube 12 inserted into a mold, and is connected to at least the innermost layer 12 a of the laminated tube 12. A method of fusing the tube body 13 is exemplified.

  According to such a manufacturing method, the resin tube 11 composed of the laminated tube 12 and the connecting tube 13 can be efficiently mass-produced, and the resin tube 11 having no variation in quality can be provided. .

  Further, when the resin tube 11 is manufactured as described above, the outer surface of the laminated tube 12 and the outer surface of the connecting tube body 13 are made to be substantially in the same plane as shown in FIG. Is also effective. In this way, it is possible to secure a large area of the fused portion between the laminated tube 12 and the connecting tube 13, to obtain a stronger and more stable fusion strength, and to improve the appearance. In addition, handleability is improved.

  FIG. 3 is a view showing an example of the connection structure of the resin tube 11, wherein the material of the innermost layer 12 a of the laminated tube 12 and the connecting tube 13 is an olefin-based thermoplastic elastomer, and the connecting tube 13 is It is fitted to the outside of a mating member 21 such as a pipe, and the outer periphery of the fitting portion of the connecting tube 13 is tightened by a belt-like clamp 22 whose length can be adjusted.

  The above connection structure is suitable, for example, for a cooling water circulation system of an automobile, and in the innermost layer 12a of the laminated tube 12 and the connecting pipe body 13, heat resistance, hydrolyzability, and barrier property against cooling water are good. The degradation of quality over a long period of time will be extremely small.

  FIG. 4 is a view showing still another embodiment of the resin tube of the present invention. In the resin tube 11 shown in the drawing, a protective layer 14 made of a thermoplastic resin is bonded to the outer surface of the connecting tube body 13. It is provided. The material of the protective layer 14 is not particularly limited as long as it has functions such as weather resistance, heat resistance, ozone resistance, and chemical resistance. For example, the same material as the outermost layer 12b of the laminated tube 11 is used. In this case, it is desirable that the thickness of the outermost layer 12b be thinner than that of the outermost layer 12b so that the assembling property with respect to a mating member such as a pipe can be improved.

  In the resin tube 11 provided with the protective layer 14 described above, the weather resistance and heat resistance of the connecting pipe body can be ensured, and the deterioration of the quality is extremely small over a long period of time.

(Example 1)
Polypropylene with a tensile elastic modulus of 850 MPa (Sun Allomer PB370, wall thickness 1.5 mm) is used for the outermost layer, and an olefin-based elastomer with a hardness of 80 (Suntoprene 101-80, wall thickness 0.5 mm made by AES Japan) is used for the innermost layer. Using, a two-layer laminated tube (inner diameter φ30 mm) was formed by coextrusion. After the end portion of this laminated tube is inserted into a mandrel (φ34 mm) under heating to expand the diameter, the end portion of the laminated tube is inserted into a mold, and an olefin elastomer having a hardness of 73 (manufactured by AES Japan) Santoplane 101-73) is injected to form a connecting tube (inner diameter φ30 mm, wall thickness 4 mm, length 30 mm from the end of the tube), and the connecting tube and laminated tube are fused by hot plate. To obtain a resin tube as shown in FIG.

(Example 2)
Polypropylene with a tensile elastic modulus of 850 MPa (Sun Allomer PB370, wall thickness 1.5 mm) is used for the outermost layer, and an olefin-based elastomer with a hardness of 80 (Suntoprene 101-80, wall thickness 0.5 mm made by AES Japan) is used for the innermost layer. Using, a two-layer laminated tube (inner diameter φ30 mm) was formed by coextrusion. After the end portion of this laminated tube is inserted into a mandrel (φ34 mm) under heating to expand the diameter, the end portion of the laminated tube is inserted into a mold, and an olefin elastomer having a hardness of 70 (manufactured by AES Japan). By injecting the santoprene 101-73), a connecting tube (inner diameter φ 30 mm, thickness 4 mm, length 30 mm from the end of the tube) is formed, and the connecting tube and the laminated tube are joined together. A resin tube as shown in 2 was obtained.

(Example 3)
Polypropylene with a tensile elastic modulus of 850 MPa (Sun Allomer PB370, wall thickness 1.5 mm) is used for the outermost layer, and an olefin-based elastomer with a hardness of 73 (AES Japan Santoprene 101-73, wall thickness 0.5 mm) is used for the innermost layer. Using, a two-layer laminated tube (inner diameter φ30 mm) was formed by coextrusion. After the end portion of the laminated tube is inserted into a mandrel (φ34 mm) under heating to expand the diameter, the end portion of the laminated tube is inserted into a mold, and the same material as the innermost layer of the laminated tube is injected. As a result, a connecting tube (inner diameter φ 30 mm, wall thickness 4 mm, length 30 mm from the end of the tube) is formed, the connecting tube and the laminated tube are joined, and a resin tube as shown in FIG. 2 is formed. Obtained.

Example 4
Polypropylene with a tensile elastic modulus of 850 MPa (Sun Allomer PB370, wall thickness 1.5 mm) is used for the outermost layer, and an olefin-based elastomer with a hardness of 73 (AES Japan Santoprene 101-73, wall thickness 0.5 mm) is used for the innermost layer. Using, a two-layer laminated tube (inner diameter φ30 mm) was formed by coextrusion. After the end portion of this laminated tube is inserted into a mandrel (φ34 mm) under heating to expand the diameter, the end portion of the laminated tube is inserted into the mold, and the same material as the innermost layer of the laminated tube is placed in the main body. In addition, with the same material as the outermost layer of the laminated tube as a protective layer, a connecting tube (inner diameter φ 30 mm, wall thickness: outer layer 0.2 mm, inner layer 3.8 mm, length 30 mm from the end of the tube) is injection molded, The connecting tube and the laminated tube were joined to obtain a resin tube as shown in FIG.

(Example 5)
A polyester elastomer with a tensile modulus of 232 MPa is used for the outermost layer (Hytrel 7277 manufactured by Toray DuPont, wall thickness 1.5 mm), maleic anhydride-modified polypropylene (wall thickness 0.1 mm) is used for the intermediate layer, and hardness 73 is used for the innermost layer. A three-layer laminated tube (inner diameter: 30 mm) was molded by coextrusion using an olefin-based elastomer (Sant Plain 101-73 manufactured by AES Japan, wall thickness 0.4 mm). After the end portion of this laminated tube is inserted into a mandrel (φ34) under heating to expand the diameter, the end portion of the laminated tube is inserted into a mold and the same material as the innermost layer of the laminated tube is injected. As a result, a connecting tube (inner diameter φ 30 mm, wall thickness 4 mm, length 30 mm from the end of the tube) is formed, and the connecting tube and the laminated tube are joined together. As shown in FIG. A resin tube was obtained in which the inner and outer surfaces of the laminated tube were both continuous in the same plane.

  In Examples 1 to 4, the hardness was measured at room temperature using a type A durometer shown in JIS K6253. The tensile modulus was measured in accordance with JIS K7113, and the tensile test speed was 500 mm / min at room temperature.

(Comparative Example 1)
A three-layer laminated tube was prepared based on Example 4, this laminated tube was fitted to the outside of a pipe joint (φ32 mm), and the outer periphery of the fitting portion was tightened with a leaf spring clamp.

(Comparative Example 2)
An EPDM rubber hose with reinforcing yarn (φ30 mm) used in conventional water-based piping was used, this rubber hose was fitted to the outside of the pipe joint (φ32 mm), and the outer periphery of the fitting portion was fastened by a leaf spring clamp.

(Evaluation methods)
Insertion force With respect to the pipe joint (φ32 mm), the end of the tube was inserted at a speed of 100 mm / min to a position 30 mm from the end, and the maximum load at that time was measured. At this time, a neutral detergent diluted twice with water was used as an insertion aid, and the neutral detergent was applied to the inner surface from the end of the tube to a position of 30 mm.

◎ Adhesive strength of connecting tube As an evaluation of adhesion between connecting tube and laminated tube, the connecting tube is fixed to a jig and the laminated tube is pulled at a speed of 500 mm / min. The load when material breakage occurred was measured.

◎ Leakage test After fitting the end of the tube to the outside of the pipe joint (φ32mm) and attaching a clamp to the outer periphery of this fitting, supply automotive cooling water diluted to 50% with water to the tube. The inside was pressurized to 0.3 Mpa at a pressure increase rate of 0.5 Mpa / min, and the presence or absence of leakage was observed. At this time, in Table 1 to be described later, the case where leakage occurred was marked with ◯, and the case where leakage did not occur was marked with ×. The mass ratio is shown as a relative ratio with the mass when the total length of the tube is 500 mm as the mass of Comparative Example 2 being 100. The samples were new and after dry heat deterioration (120 ° C. × 250 h). The above test results are shown in Table 1.

  As is clear from Table 1, the resin tubes of Examples 1 to 5 are superior in comparison with Comparative Example 1 in terms of insertion force and leakage pressure, and compared with Comparative Example 2 (conventional structure). However, since the insertion force and the leakage performance were equal or better, and the lightening effect was obtained, the effectiveness of the resin tube of the present invention could be confirmed.

It is sectional drawing of the one side omission which shows one Embodiment of the resin-made tubes of this invention. It is sectional drawing of the one side omission which shows other embodiment of resin-made tubes. It is sectional drawing of the omission of one side which shows an example of the connection structure of resin tubes. It is sectional drawing of the one side omission which shows other embodiment of resin-made tubes. It is sectional drawing which shows the fastening structure of the conventional rubber tube. It is sectional drawing which shows the fastening structure of the conventional resin tube.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Resin tube 12 Laminated tube 12a Innermost layer 12b Outermost layer 13 Connection pipe body 14 Protection layer 21 Opposing member 22 Clamp

Claims (6)

At least two or more resin layers are concentrically laminated, and the innermost layer is made of a thermoplastic resin having a hardness of 90 or less, and at least one of the layers other than the innermost layer is made of a thermoplastic resin having a tensile elastic modulus of 30 MPa or more. Laminated tubes,
A connecting tube made of a thermoplastic resin containing 50% by mass or more of the material forming the innermost layer of the laminated tube;
With the diameter of the end of the laminated tube expanded, at least the innermost layer of the laminated tube and the connecting tube are connected by fusion, and the inner surface of the laminated tube and the inner surface of the connecting tube are substantially flush with each other. A resin tube characterized by having been made.   2. The resin tube according to claim 1, wherein the innermost layer of the laminated tube and the connecting tube are made of the same material, and are both made of a thermoplastic resin having a hardness of 80 or less.   The resin tube according to claim 1 or 2, wherein a protective layer made of a thermoplastic resin is provided on an outer surface of the connecting pipe body.   When manufacturing the resin tube according to any one of claims 1 to 3, the connecting tube is injection-molded with the end portion of the laminated tube inserted into the mold, and at least the innermost layer of the laminated tube A method for producing a resin tube, comprising fusing a connecting tube.   The method for producing a resin tube according to claim 4, wherein the outer surface of the laminated tube and the outer surface of the connecting tube body are made to be substantially the same surface.   The material of the innermost layer of the laminated tube and the connecting tube is an olefin-based thermoplastic elastomer, and the connecting tube is fitted to the outside of a mating member such as a pipe, and the outer periphery of the fitting portion of the connecting tube is Resin tube connection structure characterized by tightening with a clamp.

Images