TW201932289A - A composite tube and a method of manufacturing the same - Google Patents

Abstract

A composite tube includes: a tubular pipe body; an overlaying layer composed of a resin material, being tubular and covering the periphery of the pipe body, in which an annular mountain portion outwardly protruded towards a radial direction and an annular valley portion recessed on the outside of the radial direction are formed alternately in an axial direction of the pipe body in a bellows shape; and an intermediate layer abutting widthwise the two side surfaces of a porous resin layer in a form being tubular and disposed between the pipe body and the overlaying layer to be sandwiched between the valley portion and the pipe body, and the locations that the two side surfaces are abutted opposite the parting lines of the overlaying layer relative to the peripheral direction of the pipe body.

Description

Composite pipe and composite pipe manufacturing method

The present disclosure relates to a method of manufacturing a composite pipe and a composite pipe.

In the past, a composite tube in which a plurality of layers of tubes were stacked to form a composite tube was known. For example, Japanese Laid-Open Patent Publication No. 2004-322583 describes a bellows in which a foam layer is provided between a tubular outer layer and an inner layer.

In the case of a bellows as shown in Japanese Laid-Open Patent Publication No. 2004-322583, when a composite pipe having a porous resin layer is provided between the outer cladding layer and the inner pipe body, the porous resin layer may be formed. The tubular porous resin sheet is formed into a tubular shape by abutting both end faces in the width direction. In this case, the porous resin sheet is inserted into the mold while the both end faces are wound in the tubular body and the outer periphery is covered with the resin material for forming the coating layer. Then, as the mold is closed, the end faces of the mutually opposing porous resin sheets move in the direction in which they approach each other and come into contact with each other. At this time, the resin material covering the outer periphery of the porous resin sheet is slackened by the movement of both end faces of the porous resin sheet. Then, the slack portion is formed into a coating layer having a burr by being placed on the parting surface of the mold.

The present disclosure provides a method of manufacturing a composite pipe and a composite pipe which are less likely to cause burrs in the coating layer.

The composite pipe system of the first aspect has a tubular pipe body; a coating layer composed of a resin material, which is tubular and covers the outer circumference of the pipe body, and is formed radially outward in the axial direction of the pipe body. a convex ring-shaped mountain portion and a ring-shaped valley portion having a concave outer side in the radial direction to form a bellows shape; and an intermediate layer The tubular porous resin sheet is formed into a tubular shape in a state in which both end faces in the width direction are disposed, and is disposed between the tubular body and the coating layer to be placed between the valley portion and the tubular body. Further, the abutting position of the both end faces and the parting line of the coating layer are disposed at positions different from each other in the circumferential direction of the pipe body.

In the composite pipe according to the first aspect, an intermediate layer is formed between the pipe body and the coating layer, and the intermediate layer is formed into a tubular shape while being in contact with both end faces in the width direction of the strip-shaped porous resin sheet. . Then, the abutting position of the parting line of the coating layer and the porous resin sheet is disposed at a position different from the circumferential direction of the tube body.

In other words, when a mold is used to form a coating layer on the outer periphery of the porous resin sheet, the porous resin sheet is in a state in which the opposing positions of the both end faces in the width direction are shifted with respect to the parting surface of the mold. It is configured. Then, with the mold closing, the both end faces of the porous resin sheet abut against each other at a position different from the parting surface of the mold.

When the mold is closed, the end faces of the mutually facing porous resin sheets move in the direction in which they approach each other and come into contact with each other. Then, the resin material for forming the coating layer covering the outer periphery of the porous resin sheet forms slack in the vicinity of both end faces of the porous resin sheet.

At this time, the both end faces of the porous resin sheet are in contact with each other at a position different from the parting surface of the mold. Then, the slack portion is pressed and disappears by the cavity surface of the mold. Further, since the both end faces of the porous resin sheet are not disposed at the position corresponding to the parting surface of the mold, it is difficult to form the slack portion. Thereby, it is difficult to produce a slack portion which is placed on the parting surface. As a result, the coating layer is less prone to burrs.

The composite pipe system of the second aspect has a tubular pipe body; a coating layer composed of a resin material, which is tubular and covers the outer circumference of the pipe body, and is formed radially outward in the axial direction of the pipe body. The protruding mountain portion and the annular valley portion having a concave outer side in the radial direction are in a bellows shape; and the intermediate layer is in a state in which both end faces in the width direction of the strip-shaped porous resin sheet are welded. The tubular body is formed between the tubular body and the coating layer and disposed between the valley portion and the tubular body.

In the composite pipe of the second aspect, an intermediate layer is disposed between the pipe body and the coating layer, and the intermediate layer is formed into a tubular state in a state in which both end faces in the width direction of the strip-shaped porous resin sheet are welded. .

In other words, in the state in which both end faces of the porous resin sheet are welded, the outer periphery of the porous resin sheet is coated with a resin material for forming a coating layer. Therefore, when the mold is closed, the resin material for forming the coating layer is less likely to be slack.

On the other hand, when both end surfaces of the porous resin sheet are not welded, the porous resin sheet is intended to return to its original shape, and a gap is formed between both end faces. Then, at the time of closing the mold, the both end faces are moved by an external force toward each other. Then, the resin material for forming the coating layer covering the outer periphery of the porous resin sheet forms slack in the vicinity of both end faces of the porous resin sheet. When the above-described slack portion is formed, the slack portion may be placed on the parting surface of the mold, and there is a possibility that a burr layer is formed.

However, in the composite pipe according to the second aspect, it is difficult to form a slack portion on the parting surface by the resin material for forming the coating layer covering the outer periphery of the porous resin sheet. As a result, the coating layer is less prone to burrs.

The composite pipe of the third aspect is attached to the composite pipe of the first aspect, and the abutting position is disposed at a position farthest from the parting line of the coating layer in the circumferential direction of the pipe body.

In the composite pipe of the third aspect, the contact position of the porous resin sheet is disposed at a position farthest from the parting line of the coating layer in the circumferential direction of the pipe body. Thus, the slack formed at the time of closing the mold is formed at a position farthest from the parting surface of the mold. As a result, the coating layer is less prone to burrs. Further, even if the abutting position of the porous resin sheet is partially displaced from the position farthest from the parting line of the coating layer, the portion is less likely to be burred.

The composite pipe of the fourth aspect is in the composite pipe of any of the first to third states, and the resin material forming the coating layer has a Melt flow rate (MFR) of 0.25 or more and 1.2 or less.

In the composite tube of the fourth aspect, when the MFR is 0.25 or more, the resin of the coating layer easily enters the porous structure of the intermediate layer, and the adhesion between the intermediate layer and the coating layer can be improved. Further, when the MFR is 1.2 or less, burrs are less likely to occur.

The manufacturing method of the composite pipe of the fifth aspect has a step of winding the both end faces of the strip-shaped porous resin sheet in the outer circumference of the annular pipe body, and applying a resin material to the porous resin sheet. And a step of arranging the tube body, the porous resin sheet, and the resin material in the mold in a state in which the opposing positions of the both end faces are offset from the parting surface of the mold, and closing the mold, and The both end faces are abutted to form an intermediate layer, and a step of forming a coating layer formed of the resin material is formed on the outer periphery of the intermediate layer.

In the method of producing a composite tube according to the fifth aspect, when a coating layer is formed on the outer periphery of the porous resin sheet using a mold, the porous resin sheet is formed on both end faces in the width direction with respect to the parting surface of the mold. The position of the opposite position is shifted. Then, with the mold closing, the both end faces of the porous resin sheet abut against each other at a position different from the parting surface of the mold.

When the mold is closed, the end faces of the mutually facing porous resin sheets move in the direction in which they approach each other and come into contact with each other. Then, the resin material for forming the coating layer covering the outer periphery of the porous resin sheet forms slack in the vicinity of both end faces of the porous resin sheet.

At this time, the both end faces of the porous resin sheet are in contact with each other at a position different from the parting surface of the mold. Then, the slack portion is pressed and disappears by the cavity surface of the mold. Further, since the both end faces of the porous resin sheet are not disposed at the position corresponding to the parting surface of the mold, it is difficult to form the slack portion. Thereby, it is difficult to produce a slack portion which is placed on the parting surface. As a result, the coating layer is less prone to burrs.

The manufacturing method of the composite pipe of the sixth aspect has the following steps: a step of winding the both end faces of the strip-shaped porous resin sheet in the outer circumference of the annular pipe body; and a step of welding the both end faces; coating the resin material a step of coating the outer periphery of the porous resin sheet; and disposing the tube, the porous resin sheet, and the resin material in a mold to close the mold, and abutting the both end faces to form an intermediate layer, and The outer periphery of the intermediate layer forms a coating layer formed by the resin material.

In the method of producing a composite tube according to the sixth aspect, in a state in which both end faces of the porous resin sheet are welded, a resin material for forming a coating layer is applied to the outer periphery of the porous resin sheet. Therefore, when the mold is closed, the resin material for forming the coating layer is less likely to be slack. As a result, the coating layer is less prone to burrs.

According to the present disclosure, the coating layer of the composite tube is less prone to burrs.

10‧‧‧Composite tube

12‧‧‧ tube body

13‧‧‧Low-friction resin layer

14‧‧‧Porous resin layer

14A‧‧‧Compressed Maintenance Department

14B‧‧‧ convex

14L‧‧‧ Abutment

14R‧‧‧ welded joint

14S‧‧‧Porous resin sheet

14SA‧‧‧ end face

14SB‧‧‧ end face

15S‧‧‧Flake components

20‧‧‧coating

20A‧‧‧Resin

20T‧‧‧ slack

21‧‧‧Tubular extrudate

22‧‧‧Mountain

22A‧‧‧Outer side wall

22B‧‧‧ side wall

22C‧‧‧Outer bending

23‧‧‧ Mountain Space

24‧‧‧ Valley Department

24A‧‧‧ inner side wall

24B‧‧‧ side wall

24C‧‧‧Inside bending

30‧‧‧Manufacture of equipment

32‧‧‧Exporting machine

34‧‧‧Mold

36‧‧‧Mold

36A‧‧‧ Cavity

36B‧‧‧ inside protrusion

36C‧‧‧ attracting holes

36D‧‧‧分模面

38‧‧‧Cooling trough

39‧‧‧ extraction device

45‧‧‧ Relative humidity

100‧‧‧Composite tube

141, 142‧‧‧ porous resin layer

A, B, H‧‧ arrows

H1, H2‧‧‧ thickness

L1, L2‧‧‧ length

M‧‧‧Intermediate

PL‧‧ ‧ parting line

R‧‧‧ radial

△R‧‧‧radius difference

S‧‧‧ axial

V2‧‧‧ opposite position

V‧‧‧ opposite position

W‧‧‧ arrow

Y‧‧‧Manufacture direction

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view showing a composite tube associated with an embodiment of the present disclosure.

Figure 2 is a longitudinal cross-sectional view showing a composite tube in accordance with an embodiment of the present disclosure.

Fig. 3 is an enlarged partial cross-sectional view showing the composite tube of the embodiment of the present disclosure.

4 is a perspective view showing a composite tube related to other embodiments of the present disclosure.

Fig. 5 is a longitudinal cross-sectional view showing a state in which the end portion of the tubular body of the composite pipe according to the embodiment of the present disclosure is exposed.

Fig. 6 is a view showing a process of shortening deformation of the coating layer and the porous resin layer in the longitudinal section of Fig. 3.

Fig. 7 is a view showing a state in which the coating layer and the porous resin layer are shortened and deformed in the longitudinal section of Fig. 3;

Fig. 8 is a perspective view showing a state in which the end portion of the tubular body of the composite pipe according to the embodiment of the present disclosure is exposed.

Fig. 9 is a view showing a manufacturing process of the composite pipe according to the first embodiment of the present disclosure.

FIG. 10 is a view for explaining the force acting on the porous resin layer from the coating layer when the coating layer after the deformation is restored in the composite pipe having the tubular body, the porous resin layer, and the bellows-like coating layer; A longitudinal sectional view of the force acting on the porous resin layer from the tube body.

Fig. 11 is a longitudinal cross-sectional view showing a modified example in which a low friction resin layer is provided in a composite pipe according to an embodiment of the present disclosure.

Fig. 12A is a perspective view showing a state in which a porous resin sheet for forming a porous resin layer is wound around a tubular body in a composite tube according to an embodiment of the present disclosure.

Fig. 12B is a perspective view showing a state in which a porous resin sheet has been wound around a tubular body in the composite tube according to the embodiment of the present disclosure.

Fig. 13A is a cross-sectional view showing a state before the mold is closed in the manufacturing process of the composite pipe according to the first embodiment of the present disclosure.

Fig. 13B is a cross-sectional view showing a state in which the wave mold is closed after the mold is manufactured in the manufacturing process of the composite pipe according to the first embodiment of the present disclosure.

Fig. 14 is a partial cross-sectional enlarged view showing the state of both end faces of the porous resin sheet and the resin layer in the mold closing of the wave mold.

Fig. 15A is a cross-sectional view showing a state before the mold is closed in the manufacturing process of the composite pipe of the comparative example.

Fig. 15B is a cross-sectional view showing a state in which the wave mold is closed after the mold is produced in the manufacturing process of the composite pipe of the comparative example.

Fig. 16 is a view showing a manufacturing process of a composite pipe according to a second embodiment of the present disclosure.

Fig. 17A is a cross-sectional view showing a state before the mold is closed in the manufacturing process of the composite pipe according to the second embodiment of the present disclosure.

17B is a cross-sectional view showing a state in which the wave mold is closed after the mold is manufactured in the manufacturing process of the composite pipe according to the second embodiment of the present disclosure.

[First embodiment]

Hereinafter, the first embodiment of an example of a composite pipe according to the present disclosure will be described in detail with reference to the drawings. In the drawings, constituent elements indicated by the same reference numerals are intended to be the same constituent elements. Further, each component is not limited to one, and a plurality of components may be present. In addition, in the embodiment described below, the description of the overlapping configurations and symbols will be omitted. Further, the present disclosure is not limited to the following embodiments, and may be appropriately modified within the scope of the gist of the present disclosure.

In the present specification, the term "process" is not only an independent process, but even if it cannot be clearly distinguished from other processes, the process is also included in the term as long as the purpose can be achieved. In the present specification, as for the amount of each component in the composition, if a plurality of substances conforming to each component are present in the composition, unless otherwise specified, it means the total amount of the plurality of substances present in the composition. the amount. In the present specification, the term "main component" means a component having the highest content of the mass in the mixture unless otherwise specified.

<composite tube>

The composite pipe according to the present disclosure has a tubular pipe body; a coating layer which is tubular and covers the outer periphery of the pipe body; and a porous resin layer which is disposed between the pipe body and the coating layer. The tube system is composed of a resin material. The coating layer is composed of a resin material. Further, the annular mountain portion whose shape is convex toward the outside in the radial direction and the annular valley portion which is recessed on the outer side in the radial direction are alternately formed in the axial direction of the tubular body to form a bellows shape, and are guided to the tubular body. The outer circumference can be shortened in the axial direction. The porous resin layer is disposed so as to be placed between the valley portion and the tube body.

Next, an example of a composite pipe for carrying out the present disclosure will be described with reference to the drawings. The composite pipe 10 according to the present embodiment shown in FIG. 1 includes a pipe body 12, a porous resin layer 14, and a coating layer 20.

(tube body)

The tubular body 12 is tubular and is a resin tube composed of a resin material. Examples of the resin in the resin material include polyolefins such as polybutene, polyethylene, crosslinked polyethylene, and polypropylene, and vinyl chloride. The resins may be used alone or in combination of two or more. Among them, polybutene can be suitably used, and it is preferable to contain polybutene as a main component, for example, a resin material constituting the tubular body, and more preferably contains 85% by mass or more.

Further, the resin material constituting the tube body may contain other additives.

The diameter (that is, the outer diameter) of the tubular body 12 is not particularly limited, but may be, for example, 10 mm or more and 100 mm or less, and preferably 12 mm or more and 35 mm or less. Moreover, the thickness of the pipe body 12 is not particularly limited, and is, for example, 1.0 mm or more and 5.0 mm or less, and preferably 1.4 mm or more and 3.2 mm or less.

(cladding layer)

The coating layer 20 is tubular and covers the outer circumference of the tubular body 12 and the porous resin layer 14. The porous resin layer 14 is disposed between the tube body 12 and the coating layer 20. The coating layer 20 is composed of a resin material. The resin in the resin material constituting the coating layer 20 is exemplified by polyolefins such as polybutene, polyethylene, polypropylene, and crosslinked polyethylene, and vinyl chloride. The resins may be used alone or in combination of two or more. Among them, a low-density polyethylene may be suitably used, and it is preferable to contain a low-density polyethylene as a main component, for example, a resin material constituting a coating layer, preferably 80% by mass or more, and more preferably contains 90% by mass or more.

Further, the melt index (MFR; Melt Flaw Rate) of the resin to be used is preferably 0.25 or more, more preferably 0.3 or more, still more preferably 0.35 or more and 1.2 or less. When the MFR is 0.25 or more, the resin of the coating layer 20 easily enters the porous structure of the porous resin layer 14. Therefore, the adhesion between the porous resin layer 14 and the valley portion 24 of the coating layer 20, which will be described later, can be improved. Further, by setting the MFR to 1.2 or less, burrs are less likely to occur. If the MFR is larger than 1.2, the molten resin may easily flow into the parting surface of the mold for forming the coating layer 20. Therefore, it becomes easy to produce burrs. Further, the resin material constituting the coating layer may contain other additives.

As shown in Fig. 2, the covering layer 20 is bellows-shaped, and the annular portion 22 which is convex outward in the radial direction and the ring in the radial outer side are continuously formed alternately in the axial direction S of the tubular body 12. Shaped valley 24. The mountain portion 22 is disposed closer to the outer side of the radial direction R than the valley portion 24. As shown in FIG. 3, the portion of the coating layer 20 which is closest to the radially outer side is the outer side wall 22A, and the portion closest to the radially inner side is the inner side wall. 24A, the radially outer outer side wall 22A and the intermediate portion M of the inner side wall 24A are bordered so that the radially outer side is the mountain portion 22 and the radially inner side is the valley portion 24.

The mountain portion 22 has a side wall 22A extending in the axial direction S and a side wall 22B extending from both ends of the outer side wall 22A in the radial direction R. An outer curved portion 22C is formed between the outer side wall 22A and the side wall 22B. The valley portion 24 has a side wall 24A extending in the axial direction S and a side wall 24B extending from both ends of the inner side wall 24A in the radial direction R. An inner curved portion 24C is formed between the inner side wall 24A and the side wall 24B.

A mountain space 23 recessed inward in the radial direction is formed on the radially inner side of the mountain portion 22 of the coating layer 20. Further, it is preferable that the mountain space 23 is inserted into the convex portion 14B of the porous resin layer 14 to be described later.

Further, although not particularly limited, the length L1 of the axial direction S of the mountain portion 22 is preferably set to be longer than the length L2 of the axial direction S of the valley portion 24. The length L1 is preferably 1.2 times or more the length L2 in order to secure the degree of easy deformation of the outer side wall 22A at the time of shortening the deformation described later.

Further, the length L2 is preferably 0.8 mm or more. This is because if the length L2 is less than 0.8 mm, the width of the valley portion of the mold for producing the coating layer 20 is too small. As a result, when the resin constituting the coating layer 20 is extruded at the time of production of the coating layer 20, when the resin is provided with irregularities by a mold, the portion of the resin corresponding to the valley portion of the mold is too thin. easily damaged. Therefore, it becomes difficult to form the coating layer 20. On the other hand, the length L1 is preferably 5 times or less the length L2. This is because the flexibility of the composite pipe 10 can be maintained by making the length L1 five times or less the length L2. Moreover, even if the length L1 is too long, the area of contact with the ground becomes large and the construction of the composite pipe 10 becomes difficult, and it becomes difficult to apply.

Further, as shown in FIG. 3, in the portion of the length L1-clad layer 20 which intersects the intermediate portion M, the distance between the outer side of the axial direction S in the surface seen from the outer side of the radial direction R of the cladding layer 20 (ie, The outer side of the radial direction R of the cladding layer 20 becomes the distance between the surface on the side of the axial direction S of the convex portion and the surface on the other side of the axial direction S). Further, in the portion of the length L2-based cladding layer 20 that intersects the intermediate portion M, the distance between the outer side of the axial direction S seen from the inner side of the radial direction R of the cladding layer 20 (i.e., the radial direction R of the cladding layer 20) The inner side becomes the distance between the surface on the side of the axial direction S on the convex portion and the surface on the other side in the axial direction S).

In order to shorten the coating layer 20, it is preferable that the thinnest portion of the thickness of the coating layer 20 is 0.1 mm or more, and the thickest portion is 0.4 mm or less. The thickness H1 of the outer side wall 22A is greater than the thickness H2 of the inner side wall 24A. Come thin. The thickness H1 is preferably 0.9 times or less the thickness H2 in order to secure the degree of easy deformation of the outer side wall 22A at the time of shortening the deformation described later.

The radius difference ΔR between the hill portion 22 and the outer surface of the valley portion 24 is preferably 800% or less of the thickness of the coating layer 20. If the radius difference ΔR is large, the portion along the axial direction S of the mountain portion 22 is not deformed, and when shortened, it is difficult for the valley portion 24 to bulge outward in the radial direction, or the adjacent hill portions 22 are not mutually inclined. Will be close and become a distorted deformation state. The radius difference ΔR is 800% or less of the thickness of the coating layer 20, and in order to suppress the deformation state, it is preferable that the length of the axial direction S of the mountain portion 22 is longer than the axial length of the valley portion 24. . In addition, it is better to be 600% or less.

The diameter of the coating layer 20 (that is, the outermost outer diameter) is not particularly limited, and may be, for example, a range of 13 mm or more and 130 mm or less.

(Porous resin layer)

The porous resin layer 14 is an example of an intermediate layer in the present disclosure, and is a layer made of a resin material and having a porous structure. Examples of the resin in the resin material constituting the porous resin layer 14 include polyurethane, polystyrene, polyethylene, polypropylene, and ethylene propylene diene monomer, and a mixture of the resins. Polyurethane is preferred. The porous resin layer 14 is preferably a layer containing a polyurethane as a main component (that is, a porous urethane layer). For example, it is preferable that the constituent component of the porous resin layer contains 80% by mass or more of polyurethane, more preferably 90% by mass or more. Further, the porous resin layer may contain other additives.

The ratio of the existence of the pores in the porous resin layer 14 (for example, the foaming ratio in the case of a foam) can be measured by the method described in Annex 1 of JIS K6400-1 (2012), preferably 25 / 25mm or more, more preferably 45 / 25mm or less. Further, the porous resin layer 14 is preferably a foam.

The density of the porous resin layer is preferably 12 kg/m ³ or more and 22 kg/m ³ or less. In the composite pipe, a joint or the like is connected to the end of the inner pipe body. At this time, it is required to shorten and offset the end portion of the coating layer to expose the end portion of the tubular body. However, when the coating layer is displaced, the porous resin layer does not follow and stays on the outer surface of the tube body, so that the tube body cannot be sufficiently exposed. On the other hand, when the density of the porous resin layer is 22 kg/m ³ or less, the porous resin layer has moderate flexibility. Thereby, when the end portion of the coating layer is shortened and the end portion of the tubular body is exposed, the porous resin layer satisfactorily follows the operation of the coating layer. Thus, it is suppressed from staying on the outer surface of the pipe body. As a result, the end portion of the tubular body can be easily exposed.

On the other hand, the porous resin layer has an appropriate strength by having a density of 12 kg/m ³ or more, and can suppress cracking and breakage of the porous resin layer during processing such as production of the composite pipe 10 . Density of the porous resin layer from cracking suppressing the outer surface of the tube stays in the body and the inhibition processing, perspective view of breakage, preferably 14kg / m ³ more than 20kg / m ³ or less of the range, more preferably 16kg / m ³ or more and 20 kg/m ³ or less.

Here, the density of the porous resin layer can be measured by a method specified in JIS-K7222 (2005). Further, the measurement environment was an environment having a temperature of 23 ° C and a relative humidity of 45%.

The method of controlling the density of the porous resin layer to the above range is not particularly limited, and a method of adjusting the ratio of the existence of pores in the porous resin layer (for example, a foaming ratio in the case of a foam) is exemplified. The molecular structure of the resin (that is, the method of adjusting the molecular structure of the monomer which is a raw material of the resin, or the crosslinked structure).

The porous resin layer 14 is disposed between the tube body 12 and the coating layer 20 . The porous resin layer 14 is held between the inner side wall 24A of the valley portion 24 of the cladding layer 20 and the tube body 12. Further, it is preferable that the held portion is further compressed by the inner side wall 24A and the tube body 12 to form the compression holding portion 14A.

As shown in FIG. 12A, the porous resin layer 14 is formed using a strip-shaped porous resin sheet 14S. The porous resin layer 14 is wound around the tubular body 12 as shown in FIG. 12B by forming a porous resin sheet 14S having a width substantially equal to the length of the outer circumference of the tubular body 12 as shown in FIG. 12B. The resin composition which becomes the coating layer 20 is supplied to the outer periphery as it is described later, and it is formed.

When the porous resin sheet 14S is wound around the tubular body 12, the end faces 14SA and the end faces 14SB on both sides in the width direction (the direction of the arrow W shown in Figs. 12A and 12B) of the porous resin sheet 14S are opposed to each other. Winding. At this time, the tube body 12 is viewed from the radial direction, and the contact position (abutment surface 14L) between the end surface 14SA and the end surface 14SB is wound in a substantially linear shape along the axial direction of the tube body 12. Further, when the end surface 14SA and the end surface 14SB are in contact with each other, the abutting surface 14L refers to the contact surface thereof. However, the end face 14SA and the end face 14SB may not necessarily be in contact. When the end surface 14SA and the end surface 14SB are separated from each other, the abutting surface 14L refers to the surface passing through the center of the end surface 14SA and the end surface 14SB.

The thickness of the porous resin layer 14 is the outer circumference of the tubular body 12 and the radially inner side of the inner side wall 24A in a natural state (i.e., a force such as compression or stretching does not act, a temperature of 23 ° C and a relative humidity of 45%). Above the difference, it is better to be thicker than the difference.

By compressing the compression of the holding portion 14A, the porous resin layer 14 is thinner than the natural state. The adjacent compression holding portions 14A of the porous resin layer 14 are formed with convex portions 14B therebetween. The diameter of the convex portion 14B is larger than that of the compression holding portion 14A, and protrudes into the mountain space 23. When the porous resin layer 14 is compressed by the inner side wall 24A and the tube body 12, the compression holding portion 14A and the convex portion 14B are alternately formed in the axial direction S so that the outer peripheral surface of the porous resin layer 14 is formed. Become wavy.

In addition, the thickness of the porous resin layer 14 in the natural state is preferably 1 mm or more and 20 mm or less from the viewpoint of easiness of formation of the compression-holding portion 14A compressed by the inner side wall 24A and the tube body 12. The range is preferably 2 mm or more and 15 mm or less, and more preferably 2.5 mm or more and 10 mm or less. In addition, the thickness of the porous resin layer 14 in the natural state is an average value of the values obtained by taking out the porous resin layer 14 from the composite pipe 10 and measuring three arbitrary portions. Further, the difference between the outer circumference of the tubular body 12 and the radially inner side surface of the inner side wall 24A is preferably in the range of, for example, 0.3 mm or more and 5 mm or less, more preferably 0.5 mm or more and 3 mm or less, still more preferably 1 mm or more and 2 mm or less.

The axial length S in the natural state after the porous resin layer 14 is taken out from between the tubular body 12 and the coating layer 20 is preferably 90% or more and 100% or less of the axial length S of the coating layer 20. When the porous resin layer 14 is held between the tube body 12 and the coating layer 20 in a stretched state, the porous resin layer 14 is easily formed when the coating layer 20 is shortened and deformed. The relative movement of the coating layer 20 may cause the porous resin layer 14 not to be shortened, and the outer peripheral end portion of the tubular body 12 may not be exposed. In order to suppress the relative movement of the porous resin layer 14 and the coating layer 20, the length of the axial direction S of the porous resin layer 14 in a natural state is preferably 90% or more and 100% or less of the axial length of the coating layer 20.

The method of producing the composite pipe 10 takes into consideration, for example, the following method. Specifically, first, the porous resin sheet 14S constituting the porous resin layer 14 is wound around the outer circumference of the tubular body 12. Then, in this state, the melt of the resin composition for forming the coating layer 20 is further coated, and the two pairs of dies having a semicircular arc-shaped inner surface and having the inner surface of the bellows shape are opposed to the melting The outer peripheral surface of the object is brought close to and contacted from the two directions to be solidified to form a bellows-like coating layer 20.

Further, although the porous resin layer 14 in the composite pipe 10 shown in FIGS. 1 to 3 is a single layer, the present invention is not limited thereto, and the porous resin layer 14 may be a plurality of layers. The composite pipe in which the porous resin layer 14 is a plurality of layers is exemplified by the composite pipe 100 shown in Fig. 4 (the composite pipe in which the porous resin layer 14 is two layers).

In the composite pipe 100 shown in FIG. 4, the pipe body 12, the first porous resin layer 141, the second porous resin layer 142, and the coating layer 20 are laminated in this order.

The inner peripheral surface of the porous resin layer 14 preferably contacts the outer periphery of the tubular body 12 in a comprehensive manner and covers the outer periphery of the tubular body 12. In addition, the "comprehensive contact" here does not have all the parts necessary to be completely intimate, but means that the whole face is in substantial contact.

(Production method)

Next, a method of manufacturing the composite pipe 10 of the present embodiment will be described. In the manufacturing method of the composite pipe 10, for example, the both end faces of the porous resin sheet 14S are wound around the outer periphery of the pipe body 12 to form the porous resin layer 14. Thereafter, the coating layer 20 is formed on the outer periphery of the porous resin layer 14.

For the manufacture of the composite pipe 10, for example, the manufacturing apparatus 30 shown in Fig. 9 can be used. The manufacturing apparatus 30 has an extruder 32, a die 34, a wave mold 36, a cooling tank 38, and an extracting device 39. The manufacturing process of the composite pipe 10 is performed on the right side of FIG. 9, and the pipe body 12 is manufactured while moving from the right side to the left side. Hereinafter, this moving direction is taken as the manufacturing direction Y. The die 34, the wave mold 36, the cooling groove 38, and the extracting device 39 are arranged in order with respect to the manufacturing direction Y, and the extruder 32 is disposed above the die 34.

The tube body 12 is disposed on the upstream side of the die 34, and the porous resin sheet 14S constituting the porous resin layer 14 is wound into a roll-shaped sheet-like unit 15S. When the drawing device 39 is pulled in the manufacturing direction Y, the tubular body 12 and the rolled porous resin sheet 14S are continuously drawn out. The outer peripheral surface of the tubular body 12 which is continuously drawn is placed in front of the mold 34, and as shown in Fig. 12B, the end surface 14SA and the end surface 14SB are opposed to each other, and the porous resin sheet 14S is wound around the entire circumference. In addition, the porous resin sheet 14S is inserted into the mold 34 in a relaxed state in front of the mold 34 so as not to act on the tensile force. In addition, in FIG. 12B, although the die 34 and the wave mold 36 are omitted, the end faces 14SA and the end faces 14SB of the porous resin sheet 14S are not in contact with each other at the time of insertion into the die 34 and the wave mold 36, and They are separated from each other in the circumferential direction of the tubular body 12.

As shown in FIG. 9, the outer periphery of the porous resin sheet 14S wound around the outer periphery of the pipe body 12 is extruded in a cylindrical shape, and the resin material melted from the die 34 is applied (that is, the coating layer 20 is formed. The molten material of the resin composition) forms the resin material 20A. When the resin used here is a low-density polyethylene (LDPE) having an MFR of 0.25 or more, the resin material easily enters the pores (bubbles) of the porous resin sheet to improve the porous resin sheet 14S and the resin. The adhesion of the material 20A.

After forming the tubular extrudate 21 composed of the tubular body 12, the porous resin sheet 14S, and the resin material 20A, the wave-forming mold 36 disposed on the downstream side of the die 34 is used to perform the wave-making process (that is, it is formed into a bellows shape). Process)). The wave mold 36 is, for example, a pair of molds, each of which has a semi-arc-shaped inner surface, and the inner circumference is formed with an annular cavity 36A at a portion corresponding to the mountain portion 22 of the coating layer 20, and An annular inner protrusion 36B is formed in a portion corresponding to the valley portion 24, and has a bellows shape. Each of the cavities 36A is formed with a suction hole 36C whose one end communicates with the cavity 36A and penetrates the wave mold 36. The inside of the cavity 36A is inhaled from the outside of the wave mold 36 through the suction hole 36C.

At the downstream side of the die 34, the wave mold 36 is approached from the left and right directions with respect to the resin material 20A, so that the inner faces of the pair of dies are brought into contact with the resin material 20A. Then, the wave mold 36 is formed by molding the resin material 20A while covering the outer periphery of the tubular extrudate 21 while compressing the resin material 20A by the inner protrusion 36B, and the tubular extrudate 21 together with the tube body 12 and the porous resin sheet 14S. Move toward the manufacturing direction Y. At this time, the inside of the cavity formed by the cavity 36A of the wave mold 36 is sucked by the suction hole 36C by a suction device (not shown) to be a negative pressure. Thereby, the resin material 20A is deformed toward the outer side in the radial direction R and is formed by the cavity 36A, and the bellows-like pleats in which the mountain portion 22 and the valley portion 24 are alternately arranged in the axial direction S are formed from the resin material 20A. Coating 20.

Here, when the resin material 20A in the cavity 36A is deformed outward in the radial direction R, the convex portion 14B of the porous resin sheet 14S is deeply entered toward the mountain space 23 (see a partially enlarged view shown in FIG. 9). It is stuck in the mountain space 23. The compression holding portion 14A of the porous resin sheet 14S is next to the inner side wall 24A of the valley portion 24 of the coating layer 20, and is compressed and held between the inner side wall 24A and the tube body 12.

In the state in which the wave mold 36 is closed before the mold is closed, the both end faces of the porous resin sheet 14S (that is, the end faces 14SA and the end faces 14SB) are separated from each other in the circumferential direction of the pipe body 12, as shown in Fig. 13A. . Since the porous resin sheet 14S is intended to return to the strip shape shown in Fig. 12A, the end face 14SA and the end face are provided. The 14SB will act as a force separating from each other. Thereby, the resin material 20A is closed while being subjected to tension from the porous resin sheet 14S.

The separation space (opposing position V) formed between the end surface 14SA and the end surface 14SB of the porous resin sheet 14S is disposed at a position different from the parting surface 36D of the wave mold 36 in the circumferential direction of the tube body 12. . In addition, the "position different from the parting surface 36D" means a position where the space provided by the split mold surface 36D of the pair of wave molds 36 does not overlap in the circumferential direction of the pipe body 12.

At this time, the opposing position V is preferably disposed at a position farthest from the parting surface 36D. That is, it is preferable that the opposing position V is disposed at a position corresponding to the deepest portion of the cavity 36A (i.e., the portion of the cavity 36A which is semicircular in cross section and the portion where the wiring is parallel to the parting surface 36D).

In addition, in FIG. 13A, the outer peripheral surface of the tubular body 12 is in contact with the inner peripheral surface of the porous resin sheet 14S, but the outer peripheral surface of the tubular body 12 is in a state before the wave mold 36 is closed. A gap is formed between the inner peripheral surfaces of the porous resin sheet 14S. Therefore, the end surface 14SA and the end surface 14SB are not in contact, and a separation space is formed between the end surface 14SA and the end surface 14SB.

Then, as shown in Fig. 13B, the wave mold 36 is closed to bring the parting faces 36D into contact. At this time, a gap (not shown) between the outer circumferential surface of the tubular body 12 and the inner circumferential surface of the porous resin sheet 14S is reduced, and the end surface 14SA and the end surface 14SB are in contact with each other to form the abutting surface 14L.

In the present embodiment, since the opposing position V of the end surface 14SA and the end surface 14SB is disposed at a position different from the parting surface 36D, the abutting surface 14L is disposed on the parting surface 36D of the wave mold 36. At a different location.

When the opposing position V of the end surface 14SA and the end surface 14SB of the porous resin sheet 14S before the mold closing is disposed at a position farthest from the parting surface 36D, at least a part of the abutting surface 14L in the axial direction of the tubular body 12 is It is disposed at a position farthest from the parting surface 36D in the circumferential direction of the pipe body 12.

The outer peripheral surface of the bellows-coated layer 20 formed when the wave mold 36 is closed is formed with a parting line PL (see FIG. 1) at a position corresponding to the parting surface 36D. The parting line PL is visually recognizable and cannot be visually recognized due to the accuracy of the mold, the fluidity of the resin, the presence or absence of polishing, and the like, but the parting line in the present disclosure means visually recognizable. The situation and the inability to visually identify both.

After the wave making process is performed by the wave mold 36, the coating layer 20 is cooled by the cooling grooves 38. In this way, the composite pipe 10 is manufactured.

(effect)

The operation of the composite pipe 10 and the composite pipe 10 described above will be described below. In the composite pipe 10 according to the above-described embodiment, as shown in FIG. 1, a porous resin layer 14 is disposed between the pipe body 12 and the coating layer 20, and the porous resin layer 14 is abutted against the strip-shaped porous material. The both end faces of the resin sheet 14S in the width direction (that is, the end surface 14SA and the end surface 14SB) are formed in a tubular shape. Then, the contact position (contact surface 14L) of the parting line PL of the coating layer 20 and the porous resin sheet 14S is disposed at a position different from the circumferential direction of the tube body 12.

In other words, as shown in FIG. 13A and FIG. 13B, when the wave mold 36 is used to form the coating layer 20 on the outer periphery of the porous resin layer 14, the porous resin sheet 14S is attached to the wave mold 36. The split surface 36D is placed in a state where the opposite end positions V of the both end faces in the width direction (that is, the end faces 14SA and 14SB) are shifted. Then, as shown in FIG. 13B, the end surface 14SA and the end surface 14SB are brought into contact with each other at a position different from the parting surface 36D of the wave mold 36 to form the abutting surface 14L.

When the mold is closed, as shown in Fig. 14, the end faces 14SA and 14SB facing each other are moved in the direction in which they approach each other to abut. Then, the resin material 20A covering the outer periphery of the porous resin sheet 14S has the slack portion 20T formed in the vicinity of the end surface 14SA and the end surface 14SB.

At this time, the end surface 14SA and the end surface 14SB of the porous resin sheet 14S are in contact with each other at a position different from the parting surface 36D (see FIG. 13A) of the wave mold 36. Then, the slack portion 20T is pressed and disappears due to the cavity 36A of the wave mold 36. In addition, since the end surface 14SA and the end surface 14SB of the porous resin sheet 14S are not disposed at the position corresponding to the parting surface 36D of the wave mold 36, the slack portion 20T is less likely to be formed. Thereby, the slack portion 20T placed on the parting surface by the crucible is less likely to be generated. Thus, the coating layer 20 is less prone to burrs.

Further, in the composite pipe 10 of the present embodiment, as shown in Fig. 13B, at least a part of the abutting surface 14L of the porous resin sheet 14S is disposed in the axial direction of the pipe body 12 (the front and rear direction of the paper in Fig. 13B). In the circumferential direction of the tubular body 12, the position farthest from the parting surface 36D is farthest.

When the wave mold 36 is closed, the resin material 20A and the porous resin sheet 14S are partially moved from the mold 36 to the circumferential direction of the pipe body 12 by an external force. In the above-described case, the abutting surface 14L is partially displaced from the other portions in the circumferential direction. By arranging at least a part of the abutting surface 14L in the circumferential direction of the pipe body 12 from the position farthest from the parting surface 36D, the abutting The face 14L is partially offset and configured to prevent the portion from being disposed at the same position as the split face 36D. Thereby, the generation of burrs can be suppressed.

Further, Fig. 15A shows the state before the composite tube of the comparative example is closed. In the composite pipe according to the comparative example, the porous resin sheet 14S is in a state in which the opposing positions V of the both end faces in the width direction (that is, the end faces 14SA and the end faces 14SB) are aligned with respect to the parting surface 36D of the wave mold 36. Configure it. In other words, in the circumferential direction of the tubular body 12, the gap (opposing position V2) between the opposing split mold faces 36D of the pair of wave molds 36 and the gap between the end faces 14SA and the end faces 14SB (opposing position V) are overlapping. Then, as shown in FIG. 15B, the slack portion 20T generated by the resin material 20A in the vicinity of the end surface 14SA and the end surface 14SB is held by the split surface 36D. Therefore, the coating layer of the composite pipe of the comparative example has the possibility of generating burrs.

When the composite pipe 10 according to the present embodiment is connected to the joint, the coating layer 20 in the state shown in Fig. 2 acts to shorten the axial direction S of the coating layer 20 to expose the tubular body 12. Direction of force. Thereby, as shown in FIG. 5, the coating layer 20 of one end part moves in the direction which exposes the tube body 12.

Further, at the outer side wall 22A of the mountain portion 22 and the inner side wall 24A of the valley portion 24, preferably, the length L1 of the axial direction S is longer than L2, and the thickness H1 is thinner than H2. Thereby, the outer side wall 22A is more easily deformed than the inner side wall 24A, and is deformed in a radially outward direction as shown in FIG. Next, as shown in FIG. 7, the outer curved portion 22C of the mountain portion 22 and the inner curved portion 24C of the valley portion 24 are deformed by bringing the adjacent mountain portions 22 close to each other. As a result, as shown in FIG. 5, the coating layer 20 at one end portion is more easily moved in the direction in which the tube body 12 is exposed. In this manner, when the coating layer 20 is shortened, since the outer side wall 22A is bulged and deformed, even if the bending angle or thickness of the coating layer 20 is slightly different, the valley portion 24 can be prevented from swelling outward in the radial direction. The adjacent mountain portions 22 are not close to each other and become a distorted deformation state. Thereby, the appearance defect of the shortened coating layer 20 can be suppressed.

Preferably, the porous resin layer 14 is compressed by the inner side wall 24A and the tube body 12 to adhere the compression holding portion 14A to the coating layer 20, and the convex portion 14B is engaged with the adjacent valley portion 24. Between the side walls 24B, this is easily shortened together with the cover layer 20. Thereby, as shown in FIG. 8, the end part of the pipe body 12 can be exposed.

Further, in the present embodiment, the thickness H1 of the outer side wall 22A is made thinner than the thickness H2 of the inner side wall 24A, but the thickness H1 may be the same as the thickness H2.

Further, in the present embodiment, the outer side wall 22A has a substantially linear shape in the axial direction S, but may be formed in an arc shape that bulges outward in the radial direction. Further, the inner side wall 24A may be formed in an arc shape that bulges inward in the radial direction.

Further, in the present embodiment, the porous resin layer 14 is preferably compressed by the inner side wall 24A and the tube body 12. Thereby, the compression holding portion 14A is adhered to the coating layer 20, and the convex portion 14B is engaged between the side walls 24B of the adjacent valley portions 24. Then, the porous resin layer 14 is easily followed by the operation of the coating layer 20, and the porous resin layer 14 is prevented from staying on the outer circumference of the tubular body 12, so that it can be easily shortened together with the coating layer 20.

Further, in the present embodiment, the porous resin layer 14 is in full contact with the outer peripheral surface of the tubular body 12. Then, after the tube body 12 and the porous resin layer 14 and the coating layer 20 are relatively moved to expose the end portion of the tube body 12, the friction between the outer circumference of the tube body 12 and the inner circumference of the porous resin layer 14 can be obtained. The force is used to easily hold the porous resin layer 14 and the coating layer 20 at the shortened position.

Further, in the present embodiment, the compression holding portion 14A of the porous resin layer 14 is adhered to the coating layer 20, and the convex portion 14B is engaged between the side walls 24B of the adjacent valley portions 24. Then, the porous resin layer 14 is easily followed by the operation of the coating layer 20, and the porous resin layer 14 is prevented from staying on the outer circumference of the tubular body 12, so that it can be easily shortened together with the coating layer 20.

(low friction resin layer)

Further, the composite pipe 10 of the above-described embodiment includes the tubular body 12, the porous resin layer 14, and the coating layer 20. The tubular body 12 is directly covered by the porous resin layer 14, but the embodiment of the present disclosure Not limited to this. For example, as shown in FIG. 11, a low friction resin layer 13 may be interposed between the tube body 12 and the porous resin layer 14.

The low-friction resin layer 13 is composed of a resin material, and is a layer in which the sliding resistance value at the inner peripheral surface is smaller than the sliding resistance value at the inner peripheral surface of the porous resin layer 14. The low friction resin layer 13 is exemplified by a sheet-like resin sheet layer. Examples of the resin in the resin material constituting the low friction resin layer 13 include polyester, nylon, polyolefin (for example, polyethylene, polypropylene, polybutene, etc.).

The resin material constituting the low friction resin layer 13 may contain other additives as long as it contains a resin as a main component.

The type of the low-friction resin layer 13 is exemplified by a non-woven fabric (for example, a melt blown nonwoven fabric, a spun bonded nonwoven fabric, etc.), a knitted fabric (for example, Rrussell (a fabric invented by a Swedish scientist), and a Triched warp knitted fabric. (tricot), Milanese warp knit (milanese, etc.), fabric (for example, plain weave, woven weave, weaving, weaving, weaving, etc.), film, and the like.

Among these, the low-friction resin layer 13 is preferably a polyester non-woven fabric (i.e., a non-woven fabric containing polyester as a main component), and a polyester texel warp knitted fabric (that is, a polyester containing a polyester as a main component). Nylon warp knitted fabric), nylon non-woven fabric (ie, non-woven fabric containing nylon as a main component), nylon Teli soft warp knitted fabric (ie, knitted fabric containing nylon as a main component), polyethylene film (ie A film comprising polyethylene as a main component, etc., more preferably a polyester non-woven fabric and a nylon texel warp knit.

Further, the low-friction resin layer 13 is not woven, and the basis weight of the nonwoven fabric is, for example, 10 g/m ² or more and 500 g/m ² or less, preferably 12 g/m ² or more and 200 g/m ² or less, more preferably 15 g/m. ² or more and 25 g/m2 or less.

The sliding resistance value (unit: N) at the inner peripheral surface of the low-friction resin layer 13 is not particularly limited as long as it is smaller than the sliding resistance value at the inner peripheral surface of the porous resin layer 14, but is preferably 10 or more. 24 or less is preferably 12 or more and 23 or less.

In addition, the sliding resistance value (unit: N) of the inner peripheral surface of the low-friction resin layer 13 is, for example, 0.36 times or more and 0.90 times or less of the sliding resistance value (unit: N) at the inner peripheral surface of the porous resin layer 14 . It is preferably 0.44 times or more and 0.85 times or less.

The inner peripheral surface of the low-friction resin layer 13 preferably has a comprehensive contact with the outer periphery of the tubular body 12 and covers the outer periphery of the tubular body 12. In addition, the "comprehensive contact" here does not have all the parts necessary for completeness, but means that the whole surface is in substantial contact. Therefore, for example, the porous resin layer 14 and the low friction resin layer 13 are sheet-shaped first sheets (hereinafter also referred to as "porous resin sheets") constituting the porous resin layer 14, and the low friction resin layer 13 is formed. The laminated body of the sheet-like second sheet (hereinafter also referred to as "low-friction resin sheet") is formed by winding, and the connecting portion is partially separated, or the tube body 12 and the coating layer are formed. The portion between the 20 which becomes wrinkled will be partially separated.

The thickness of the low friction resin layer 13 is preferably in the range of 0.05 mm or more and 7 mm or less, more preferably 0.08 mm or more and 5 mm or less, and still more preferably 0.1 mm or more from the viewpoint of the followability to the coating layer. 3mm or less. Further, the thickness of the low friction resin layer 13 is an average value of the values obtained by taking out the low friction resin layer 13 from the composite pipe 10 and measuring three arbitrary portions.

The composite pipe 10 including the low friction resin layer 13 is formed by the low friction resin layer 13 disposed between the pipe body 12 and the porous resin layer 14, so that the end portion of the coating layer 20 is shortened and deformed to allow the end of the pipe body 12 When the coating layer 20 is returned again after the exposure, the porous resin layer 14 can be prevented from being caught. Specifically, it is as follows.

In the composite pipe having the tubular body 12, the porous resin layer 14, and the bellows-like coating layer 20, it is required to connect the joint or the like to the end of the inner tubular body 12 as shown in FIG. The end of the coating layer is shortened and offset in the direction indicated by the arrow B to expose the end of the tubular body. Further, after the joint or the like is connected to the joint or the like, the shortened coating layer can be made to the arrow A. The direction shown is elongated and restored to cover the tube again.

As shown in FIG. 11, in the composite pipe 10 in which the low friction resin layer 13 is disposed between the pipe body 12 and the porous resin layer 14, the sliding resistance value at the inner circumferential surface of the low friction resin layer 13 is small and is easy to slide. . Then, when the end portion of the coating layer 20 is shortened and the end portion of the tubular body 12 is exposed and the coating layer is returned again, the porous resin layer 14 and the low friction resin layer 13 are opposed to the coating layer. When the 20 is extended in the axial direction and follows well, the end portion of the exposed tubular body 12 can be satisfactorily covered by the low friction resin layer 13, the porous resin layer 14, and the coating layer 20.

Here, the above-mentioned "slip resistance value" is specifically measured in the following manner. In the case of measuring the value of the sliding resistance at the inner peripheral surface of the low-friction resin layer, first, the coating layer is disposed on the outer peripheral side of the tube body, and the porous resin layer and the object to be measured as the sliding resistance value are low-friction. The resin layer is inserted between the tube body and the coating layer so that the low friction resin layer is in contact with the tube body to form a composite tube having a length of 200 mm. Then, one end portion of the composite pipe is connected to a front end portion of a dynamometer (for example, an IMADA-made popular electronic dynamometer DS2), and the force at which the coating layer at the other end portion of the composite pipe is shifted by 50 mm is measured ( Unit: N).

In the case where the sliding resistance value at the inner peripheral surface of the porous resin layer is measured, the coating layer is placed on the outer peripheral side of the tubular body, and the porous resin layer to be measured as the sliding resistance value is made porous. The resin layer is inserted between the tube body and the coating layer in such a manner as to be in contact with the tube body to form a length of 200 mm. Composite pipe. Then, the sliding resistance value of the porous resin layer was measured in the same manner as the measurement of the sliding resistance value of the low friction resin layer.

Further, in the case where the low-friction resin layer 13 is provided, it is preferable that the thickness of the porous resin layer 14 in the natural state is lower than the thickness of the rubbing resin layer 13. The porous resin layer 14 preferably has a function of thermal protection in the composite pipe 10, and the thicker the above, the thermal protection property is improved. On the other hand, when the low friction resin layer 13 is too thick, the followability of the porous resin layer 14 and the low friction resin layer 13 to the coating layer 20 is lowered. Therefore, the porous resin layer 14 is relatively thick, and the low-friction resin layer 13 is relatively thin, thereby enhancing both the above thermal protection property and the followability to the coating layer 20.

In addition, the thickness of the porous resin layer 14 in the natural state is preferably 10 times or more and 200 times or less the thickness of the low friction resin layer 13 from the viewpoint of thermal protection and followability to the coating layer, and more preferably It is 20 times or more and 150 times or less, and more preferably 25 times or more and 100 times or less.

Moreover, it is preferable that the inner peripheral surface of the porous resin layer 14 is adjacent to the outer peripheral surface of the low friction resin layer 13. By the porous resin layer 14 and the low friction resin layer 13, the followability of the porous resin layer 14 and the low friction resin layer 13 to the coating layer is further improved.

The method of attaching the porous resin layer 14 and the low-friction resin layer 13 in addition to the method of applying an adhesive between the two layers is exemplified by a flame laminate method. In the method, flame lamination is preferred. That is, the porous resin layer 14 and the low friction resin layer 13 are preferably flame laminated bodies.

In the flame lamination method, for example, the soluble substance contained in the porous resin layer 14 is thermally fused and exuded by a flame, and the exuded melt is brought into contact with the low-friction resin layer 13. Then, a laminate (hereinafter also referred to as "flame laminated adhesive body") in which the porous resin layer 14 and the low friction resin layer 13 are followed by a flame lamination method is coated with an adhesive between the two layers. The porous resin layer 14 and the low friction resin layer 13 are laminated together (hereinafter also referred to as "adhesive body using an adhesive"), and the porous resin layer 14 and the low friction resin layer 13 can be interposed. The two layers are then thinned by the subsequent layers. Then, the composite tube 10 having the flame laminated adherend has a more improved followability to the coating layer than the porous resin layer 14 and the low friction resin layer 13, and is less likely to cause burrs during the manufacturing process of the composite tube 10.

[Second embodiment]

Hereinafter, a second embodiment of an example of a composite pipe according to the present disclosure will be described in detail with reference to the drawings. In addition, the same configurations as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be appropriately omitted. In addition, the manufacturing method is the same as that of the first embodiment, and the description is omitted as appropriate.

(Porous resin layer)

In the same manner as in the first embodiment, the porous resin layer 14 of the second embodiment is formed using a strip-shaped porous resin sheet 14S as shown in Fig. 12A. In the porous resin layer 14 , a porous resin sheet 14S having a width which is substantially equal in length to the outer circumferential length of the tubular body 12 and wound in a strip shape is wound around the tubular body 12 as shown in FIG. 12B, and the end surface is formed. The 14SA is welded to the end face 14SB. Then, in this state, the melt of the resin composition for forming the coating layer 20 is further coated, and the two pairs of dies having a semicircular arc-shaped inner surface and having the inner surface of the bellows shape are opposed to the melting The outer peripheral surface of the object is brought close to and contacted from the two directions to be solidified to form a bellows-like coating layer 20.

(Production method)

In the manufacturing method of the composite pipe 10 in the second embodiment, for example, the both end faces of the porous resin sheet 14S are wound around the outer circumference of the pipe body 12, and the both end faces are welded to each other to form the porous resin layer 14. Thereafter, the coating layer 20 is formed on the outer periphery of the porous resin layer 14.

For the manufacture of the composite pipe 10, for example, the manufacturing apparatus 30 shown in Fig. 16 can be used. The manufacturing apparatus 30 has an extruder 32, a die 34, a wave mold 36, a cooling tank 38, and an extracting device 39. The manufacturing process of the composite pipe 10 is performed on the right side of FIG. 16 and the pipe body 12 is moved from the right side to the left side. Hereinafter, this moving direction is taken as the manufacturing direction Y. The die 34, the wave mold 36, the cooling groove 38, and the extracting device 39 are arranged in order with respect to the manufacturing direction Y, and the extruder 32 is disposed upstream of the die 34. Further, the upstream side of the extruder 32 is provided with a heat gun or a barrel heater, or both a heat gun and a cartridge heater (not shown), and hot air or the like can be blown as indicated by an arrow H in FIG. The position, that is, the abutting surface 14L of the end surface 14SA of the porous resin sheet 14S and the end surface 14SB, welds the end surface 14SA and the end surface 14SB. In the following description, the abutting surface 14L to be welded may be referred to as a welded surface 14R.

The tube body 12 is disposed on the upstream side of the die 34, and the sheet-like member 15S in which the porous resin sheet 14S constituting the porous resin layer 14 is wound into a roll shape is disposed. When the drawing device 39 is pulled in the manufacturing direction Y, the tubular body 12 and the rolled porous resin sheet 14S are continuously drawn out. The outer peripheral surface of the tubular body 12 which is continuously drawn is placed in front of the mold 34, and as shown in Fig. 12B, the end surface 14SA and the end surface 14SB are opposed to each other, and the porous resin sheet 14S is wound around the entire circumference. The porous resin sheet 14S is inserted into the die 34 in a state where the end surface 14SA and the end surface 14SB are welded by a heat gun.

As shown in FIG. 16 , the outer periphery of the porous resin sheet 14S wound around the outer circumference of the tubular body 12 and welded at both ends thereof is cylindrically extruded and coated with a resin material melted from the die 34 ( That is, the coating layer 20 forms a molten material of the resin composition for forming the resin material 20A. When the resin used here is a low-density polyethylene (LDPE) having an MFR of 0.25 or more, the resin material easily enters the pores (bubbles) of the porous resin sheet to improve the porous resin sheet 14S and the resin. The adhesion of the material 20A.

After forming the tubular extrudate 21 composed of the tubular body 12, the porous resin sheet 14S, and the resin material 20A, the wave-forming mold 36 disposed on the downstream side of the die 34 is used to perform the wave-making process (that is, it is formed into a bellows shape). Process)). Since this wave making process is the same as that of the first embodiment, the description thereof is omitted.

As shown in FIG. 17A, the end surface 14SA of the porous resin sheet 14S and the welded surface 14R of the end surface 14SB are disposed at a position different from the parting surface 36D of the wave mold 36 in the circumferential direction of the tubular body 12.

At this time, it is preferable that the welding surface 14R is disposed at a position farthest from the parting surface 36D. That is, it is preferable that the welding surface 14R is disposed at a position corresponding to the deepest portion of the cavity 36A (i.e., the portion of the cavity 36A which is semicircular in cross section, and the portion where the wiring is parallel to the parting surface 36D).

The outer peripheral surface of the bellows-coated layer 20 formed when the wave mold 36 is closed is formed with a parting line PL at a position corresponding to the parting surface 36D (see FIG. 1).

After the coating layer 20 is formed into a bellows shape using the wave mold 36, the coating layer 20 is cooled by using the cooling groove 38, and the bellows-shaped coating layer 20 is completed to produce the composite pipe 10. When the composite pipe 10 is continuously conveyed in the manufacturing direction Y by using the extracting device 39, the composite pipe 10 in the manufacturing device 30 is continuously manufactured.

(effect)

The operation of the composite pipe 10 and the composite pipe 10 described above will be described below. In the composite pipe 10 according to the above-described embodiment, as shown in FIG. 1, a porous resin layer 14 is disposed between the pipe body 12 and the coating layer 20, and the porous resin layer 14 is attached to a strip-shaped porous resin sheet. The both end faces in the width direction of the 14S (that is, the end faces 14SA and the end faces 14SB) are welded to each other to form a tubular shape. Then, the parting line PL of the coating layer 20 and the end surface 14SA of the porous resin sheet 14S and the welding surface 14R of the end surface 14SB are disposed at positions different from each other in the circumferential direction of the tube body 12.

In the state in which the end surface 14SA and the end surface 14SB of the porous resin sheet 14S are welded together, the outer peripheral portion of the porous resin sheet 14S is coated with a resin material forming the coating layer 20 (resin material 20A). ). Then, in the state in which the end surface 14SA of the porous resin sheet 14S and the end surface 14SB are welded to each other, the wave mold 36 is used to form the coating layer 20 on the outer periphery of the porous resin layer 14 as shown in FIG. 17A and FIG. 17B. In addition, the porous resin sheet 14S is placed in a state in which the welding surface 14R is displaced with respect to the parting surface 36D of the wave mold 36.

On the other hand, Fig. 15A shows the state before the composite pipe of the comparative example is closed. In the composite pipe according to the comparative example, both end faces in the width direction of the porous resin sheet 14S (that is, the end faces 14SA and the end faces 14SB) are not welded. Then, the porous resin sheet 14S is intended to return to its original shape, and a gap is formed between the both end faces. Further, the opposing position V of the end surface 14SA and the end surface 14SB is disposed in a state of being aligned with respect to the parting surface 36D of the wave mold 36. In other words, in the circumferential direction of the tubular body 12, the gap (opposing position V2) between the opposing split mold faces 36D of the pair of wave molds 36 and the gap between the end faces 14SA and the end faces 14SB (opposing position V) are overlapping.

As a result, as shown in FIG. 15B, the end surface 14SA and the end surface 14SB move in the direction in which they approach each other, and the slack portion 20T is formed in the vicinity of the end surface 14SA and the end surface 14SB of the resin material 20A. If the slack portion 20T is held by the split surface 36D, there is a possibility that the coating layer is burred.

On the other hand, in the composite pipe 10 according to the embodiment of the present disclosure, as shown in FIG. 17A, since the end surface 14SA of the porous resin sheet 14S and the end surface 14SB are welded, the mold 44 is closed. Further, the resin material 20A is still less likely to generate the slack portion 20T (see FIG. 15B). Thus, the coating layer 20 is less prone to burrs.

In the composite pipe 10, the welded surface 14R of the porous resin sheet 14S is displaced relative to the parting surface 36D of the wave mold 36. Therefore, even in the case where the end surface 14SA and the end surface 14SB are partially unfused as shown in Fig. 14, the slack portion 20T generated by the resin material 20A of the portion is still passed through the cavity of the wave mold 36. 36A was pressed and disappeared. Thus, the coating layer 20 is less prone to burrs.

In the above-described manner, the state in which both end faces (that is, the end faces 14SA and the end faces 14SB) of the porous resin sheet 14S in the width direction are welded is included in the axial direction of the tubular body 12, and the end faces 14SA and the end faces 14SB are partially Not welded.

Further, in the composite pipe 10 of the present embodiment, as shown in Fig. 17B, at least a part of the welded surface 14R in the porous resin sheet 14S is disposed in the axial direction of the tubular body 12 (the front-back direction of the paper in Fig. 17B). In the circumferential direction of the tubular body 12, the position farthest from the parting surface 36D is farthest.

When the wave mold 36 is closed, the resin material 20A and the porous resin sheet 14S are partially moved from the mold 36 to the circumferential direction of the pipe body 12 by an external force. In the above-described case, the welding surface 14R is partially disposed offset from the other portions in the circumferential direction. By disposing at least a part of the welding surface 14R in the circumferential direction of the pipe body 12 from the position farthest from the parting surface 36D, even if the welding surface 14R is partially displaced and arranged, it is possible to suppress the portion from being disposed in the circumferential direction. The same position as the parting surface 36D. Thereby, the generation of burrs can be suppressed.

Further, in the composite pipe 10 of the present embodiment, the welded surface 14R of the porous resin sheet 14S is displaced with respect to the parting surface 36D of the wave mold 36, but the embodiment of the present disclosure is not limited. herein. For example, the welded surface 14R of the porous resin sheet 14S may be disposed at a position corresponding to a gap (opposing position V2) of the split mold surface 36D of the pair of wave molds 36. The above-described arrangement also makes it difficult for the resin material 20A of this portion to generate the slack portion 20T.

Claims (6)

A composite pipe having: a tubular pipe body; a coating layer composed of a resin material, which is tubular and covers an outer circumference of the pipe body, and a ring protruding outward in the radial direction is formed alternately in the axial direction of the pipe body The mountain portion and the annular portion having a concave outer side in the radial direction are in a bellows shape, and the intermediate layer is formed in a tubular shape in a state in which both end faces in the width direction of the strip-shaped porous resin sheet are abutted. And disposed between the tube body and the coating layer and disposed between the valley portion and the tube body, wherein a contact position between the end surfaces and a parting line of the coating layer are disposed in the tube body The pipe body is at a different position in the circumferential direction. A composite pipe having: a tubular pipe body; a coating layer composed of a resin material, which is tubular and covers an outer circumference of the pipe body, and a ring protruding outward in the radial direction is formed alternately in the axial direction of the pipe body And the intermediate layer is formed in a tubular shape in a state in which both end faces in the width direction of the strip-shaped porous resin sheet are welded, and the intermediate layer is formed in a bellows shape. And disposed between the tube body and the coating layer and disposed between the valley portion and the tube body. The composite pipe of claim 1, wherein the abutting position is disposed at a position farthest from a parting line of the coating layer in a circumferential direction of the pipe body. The composite pipe according to any one of claims 1 to 3, wherein the resin material forming the coating layer has a Melt flow rate (MFR) of 0.25 or more and 1.2 or less. A method for producing a composite pipe, comprising the steps of: winding the both end faces of the strip-shaped porous resin sheet in the outer circumference of the annular pipe body; and applying the resin material to the outer periphery of the porous resin sheet ;as well as The tube body, the porous resin sheet, and the resin material are placed in the mold to be closed while the opposing positions of the both end faces are offset from the parting surface of the mold, and the both end faces are abutted The intermediate layer is formed, and a coating layer formed of the resin material is formed on the outer periphery of the intermediate layer. A method for producing a composite pipe, comprising the steps of: winding the both end faces of the strip-shaped porous resin sheet so as to be wound around the outer circumference of the annular pipe body; and welding the both end faces; and coating the resin material thereon a step of arranging the outer periphery of the porous resin sheet; and arranging the tube, the porous resin sheet, and the resin material in a mold to mold the mold, and abutting the both end faces to form an intermediate layer, and in the intermediate layer The outer periphery forms a process of forming a coating layer formed of the resin material.