WO2019117219A1

WO2019117219A1 - Composite pipe and production method for composite pipe

Info

Publication number: WO2019117219A1
Application number: PCT/JP2018/045766
Authority: WO
Inventors: 浩平三觜
Original assignee: 株式会社ブリヂストン
Priority date: 2017-12-13
Filing date: 2018-12-12
Publication date: 2019-06-20
Also published as: TW201932289A

Abstract

A composite pipe having: a tubular pipe body; a coating layer that is tubular, covers the outer circumference of the pipe body, comprises a resin material, and has ring-shaped mountain sections protruding towards the outside in the radial direction and ring-shaped valley sections that are recessed on the outside in the radial direction, said mountain and valley sections being formed alternately in the axial direction of the pipe body and forming a bellows shape; and intermediate layers that are formed in a tubular shape in a state in which both end surfaces thereof abut in the width direction of a band-shaped porous resin sheet, are arranged between the pipe body and the coating layer, are interposed between the valley sections and the pipe body, and have the abutted position of both end surfaces and the parting line of the coating layer arranged at different positions in the circumferential direction of the pipe body.

Description

Composite pipe and method of manufacturing composite pipe

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

DESCRIPTION OF RELATED ART Conventionally, the composite pipe which laminates | stacks and forms a pipe body in multiple layers is known. For example, Japanese Unexamined Patent Publication No. 2004-322583 describes a corrugated pipe in which a foam layer is provided between a tubular outer layer and an inner layer.

In the case of forming a composite tube provided with a porous resin layer between the outer covering layer and the inner tube as in the corrugated tube disclosed in JP-A 2004-322583, the porous resin layer is It may be formed in a tubular shape by abutting both end faces in the width direction of the strip-like porous resin sheet. In this case, the porous resin sheet is wound around the tubular body with both end surfaces facing each other, and the outer periphery is inserted into the mold in a state of being covered by the resin material forming the covering layer. Then, with the mold clamping, both end surfaces of the porous resin sheets facing each other move toward each other and are abutted. At this time, slack is generated in the resin material covering the outer periphery of the porous resin sheet along with the movement of both end surfaces of the porous resin sheet. Then, the slack portion is pinched by the parting surface of the mold to form a coating layer with burrs.

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

The composite tube of the first aspect is a tubular tube, and an annular peak which is formed into a tubular shape and covers the outer periphery of the tube and which is convex radially outward, and an annular valley which is concave radially outward. Are alternately formed in the axial direction of the tubular body to form a bellows-like covering layer made of a resin material, and a tubular porous resin sheet in a state in which both end faces in the width direction are abutted And formed between the tubular body and the covering layer, and sandwiched between the valley portion and the tubular body, and the abutting positions of the both end surfaces and the parting line of the covering layer are formed. And an intermediate layer disposed at different positions in the circumferential direction of the pipe body.

In the composite tube of the first aspect, an intermediate layer formed in a tubular shape is disposed between the tube and the covering layer in a state in which both end faces in the width direction of the strip-like porous resin sheet are abutted. And the parting line of a coating layer and the contact | abutting position of a porous resin sheet are arrange | positioned in a different position in the circumferential direction of a pipe body.

That is, when the coating layer is formed on the outer periphery of the porous resin sheet using a mold, the porous resin sheet is shifted from the facing position of both end surfaces in the width direction with respect to the parting surface of the mold. Will be placed. And with clamping, the both end surfaces of a porous resin sheet are abutted in the position different from the parting surface of a metal mold | die.

At the time of mold clamping, both end surfaces of the porous resin sheets facing each other move toward each other and are pressed against each other. For this reason, in the resin material which forms the coating layer which covers the outer periphery of a porous resin sheet, slack is formed in the both end surface vicinity of a porous resin sheet.

At this time, both end surfaces of the porous resin sheet are abutted at positions different from the parting surface of the mold. For this reason, the slack portion is pressed by the cavity surface of the mold and disappears. Moreover, since the both end surfaces of the porous resin sheet are not arrange | positioned in the position corresponding to the parting surface of a metal mold | die, it is hard to form a slack part. As a result, it is difficult to generate a slack portion pinched by the parting surface. Therefore, the coating layer is less susceptible to burrs.

The composite pipe of the second aspect is a tubular pipe body, and an annular peak portion which is formed into a tubular shape and covers the outer periphery of the pipe body and which is convex radially outward and an annular valley portion which is concave radially outer side And a cover layer made of a resin material and alternately formed in the axial direction of the tubular body and made of a resin material, and a tubular form in which both end faces in the width direction of the strip-like porous resin sheet are fused And an intermediate layer disposed between the tubular body and the covering layer and sandwiched between the valley and the tubular body.

In the composite tube according to the second aspect, an intermediate layer is disposed between the tubular body and the covering layer in a tubular shape in which both end faces in the width direction of the strip-like porous resin sheet are fused. .

That is, the resin material which forms a coating layer is apply | coated on the outer periphery of a porous resin sheet in the state by which the both-ends surface of the porous resin sheet was melt | fused. For this reason, at the time of mold clamping, slack is hard to be formed in the resin material which forms a coating layer.

On the other hand, when the both end surfaces of the porous resin sheet are not fused, the porous resin sheet tries to return to the original shape, and a gap is formed between the both end surfaces. And at the time of mold clamping, both end faces receive external force and move in a direction approaching each other. For this reason, in the resin material which forms the coating layer which covers the outer periphery of a porous resin sheet, slack is formed in the both end surface vicinity of a porous resin sheet. When such a slack portion is formed, the slack portion may be pinched by the parting surface of the mold, whereby a coating layer provided with burrs may be formed.

However, according to the composite tube of the second aspect, a slack portion pinched by the parting surface hardly occurs in the resin material forming the covering layer covering the outer periphery of the porous resin sheet. Therefore, the coating layer is less susceptible to burrs.

The composite pipe of the third aspect is, in the composite pipe of the first aspect, arranged such that the abutting position is most distant from the parting line of the covering layer in the circumferential direction of the pipe body.

In the composite pipe of the third aspect, the abutting position of the porous resin sheet is disposed at the position most distant from the parting line of the covering layer in the circumferential direction of the pipe. For this reason, the slack portion formed at the time of mold clamping is formed at the position farthest from the parting surface of the mold. For this reason, it is hard to generate | occur | produce a burr | flash in a coating layer. Moreover, even if the position where the porous resin sheet is abutted is partially deviated from the position farthest from the parting line of the coating layer, burrs hardly occur in the part.

The composite pipe of the fourth aspect is the composite pipe according to any one of the first to third aspects, wherein Melt flow rate (MFR) of the resin material forming the covering layer is 0.25 or more and 1.2 or less. is there.

In the composite tube of the fourth aspect, by setting the MFR to 0.25 or more, the resin of the cover layer can easily enter the porous structure of the intermediate layer, and the degree of adhesion between the intermediate layer and the cover layer can be enhanced. Further, by setting the MFR to 1.2 or less, burrs are less likely to occur.

In the method of manufacturing a composite tube according to the fifth aspect, a step of winding the both ends of the strip-like porous resin sheet so as to face each other on the outer periphery of the annular tube and applying a resin material to the outer periphery of the porous resin sheet And the tubular body, the porous resin sheet, and the resin material are disposed in the mold and clamped in a state where the opposing positions of the both end faces are shifted from the parting surface of the mold, and the both end faces are And forming an intermediate layer, and forming a covering layer formed of the resin material on the outer periphery of the intermediate layer.

In the method of manufacturing a composite tube according to the fifth aspect, when forming the covering layer on the outer periphery of the porous resin sheet using the mold, the porous resin sheet is in the width direction with respect to the parting surface of the mold. It arrange | positions in the state which shifted the opposing position of both end surfaces. And with clamping, the both end surfaces of a porous resin sheet are abutted in the position different from the parting surface of a metal mold | die.

A method of manufacturing a composite tube according to a sixth aspect of the present invention comprises the steps of: winding both end faces of a band-like porous resin sheet so as to face each other on the outer periphery of an annular tube; fusing the both end faces; A step of applying a resin material to the outer periphery of the sheet, placing the tubular body, the porous resin sheet and the resin material in a mold and clamping them, and pressing the both end faces to form an intermediate layer, Forming a covering layer formed of the resin material on the outer periphery of the intermediate layer.

In the method of manufacturing a composite tube according to the sixth aspect, the resin material forming the covering layer is applied to the outer periphery of the porous resin sheet in a state where both end surfaces of the porous resin sheet are fused. For this reason, slack is hard to be formed in the resin material which forms a coating layer at the time of mold clamping. Therefore, the coating layer is less susceptible to burrs.

According to the present disclosure, burrs are less likely to occur in the coating layer of the composite tube.

1 is a perspective view of a compound tube according to an embodiment of the present disclosure. It is a longitudinal section showing a compound tube concerning an embodiment of this indication. 1 is a partially enlarged view of a longitudinal cross section of a composite tube according to an embodiment of the present disclosure. FIG. 7 is a perspective view of a composite tube according to another embodiment of the present disclosure. It is a longitudinal section showing the state where the end of the tube of a compound tube concerning an embodiment of this indication was exposed. It is a figure which shows the process in which a coating layer and a porous resin layer are shortened and deformed in the longitudinal cross-section part of FIG. In the longitudinal cross-section part of FIG. 3, it is a figure which shows the state by which the coating layer and the porous resin layer were shortened and deformed. FIG. 7 is a perspective view showing the end of the tubular body of the composite tube according to the embodiment of the present disclosure in an exposed state. It is a figure showing a manufacturing process of a compound tube concerning a 1st embodiment of this indication. In the case of a composite tube having a tubular body, a porous resin layer, and a bellows-like coating layer, when the shortened and deformed coating layer is put back, the force acting from the coating layer on the porous resin layer and the force acting from the tube It is a longitudinal cross-sectional view for demonstrating. The composite pipe | tube which concerns on embodiment of this indication WHEREIN: It is a longitudinal cross-sectional view which shows the modification which provided the low friction resin layer. The composite pipe which concerns on embodiment of this indication WHEREIN: It is the perspective view which showed the state before winding the porous resin sheet which forms a porous resin layer in a tubular body. In a compound tube concerning an embodiment of this indication, it is a perspective view showing a state where a porous resin sheet is wound around a tube. FIG. 7 is a cross-sectional view showing a state before clamping of the wave application mold in the manufacturing process of the composite pipe according to the first embodiment of the present disclosure. It is a sectional view showing the state after clamp of a wave application mold in a manufacturing process of a compound tube concerning a 1st embodiment of this indication. It is the elements on larger scale sectional view showing the state of the both-ends side of a porous resin sheet, and the resin layer under clamping of a wave application mold. It is sectional drawing which showed the state before clamping of a wave application mold in the manufacturing process of the composite pipe of a comparative example. It is sectional drawing which showed the state after mold clamping of a wave application mold in the manufacturing process of the composite pipe of a comparative example. It is a figure showing a manufacturing process of a compound tube concerning a 2nd embodiment of this indication. It is sectional drawing which showed the state before clamp of a wave application | coating die in the manufacturing process of the composite pipe which concerns on 2nd Embodiment of this indication. It is sectional drawing which showed the state after mold clamping of a wave application mold in the manufacturing process of the composite pipe which concerns on 2nd Embodiment of this indication.

First Embodiment
Hereinafter, 1st Embodiment which is an example of the compound pipe concerning this indication is described in detail, referring to drawings suitably. Components indicated by the same reference numerals in the drawings mean that they are the same components. Further, each component is not limited to one, and a plurality of components may exist. In addition, description may be abbreviate | omitted about the structure and code | symbol which overlap in embodiment described below. Further, the present disclosure is not limited to the following embodiments at all, and can be implemented with appropriate modifications within the scope of the purpose of the present disclosure.

In the present specification, the term “process” is not limited to an independent process, and even if it can not be clearly distinguished from other processes, the term “process” is also used if the purpose is achieved. include. In the present specification, the amount of each component in the composition is the total amount of a plurality of substances present in the composition unless a plurality of substances corresponding to each component are present in the composition. Means In the present specification, the “main component” refers to the component having the highest content by mass in the mixture, unless otherwise specified.

<Complex pipe>
The composite tube according to the present disclosure has a tubular tube, a covering layer that is tubular and covers the outer periphery of the tube, and a porous resin layer disposed between the tube and the covering layer. The tube is made of a resin material. The covering layer is made of a resin material. Further, the shape thereof is a bellows-like shape in which an annular peak that is convex outward in the radial direction and an annular valley that is concave in the outer radial direction are alternately formed in the axial direction of the tube. It can be shortened in the axial direction while being guided by the outer periphery of the body. The porous resin layer is disposed so as to be sandwiched between the valley and the tube.

Next, a mode for carrying out the composite tube of the present disclosure will be described based on the drawings, taking an example. The composite tube 10 according to the present embodiment shown in FIG. 1 includes a tube body 12, a porous resin layer 14, and a covering layer 20.

(Tube)
The tube body 12 is a resin tube which is tubular and made 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. Resin may be used alone or in combination of two or more. Among them, polybutene is suitably used, and it is preferable to contain polybutene as a main component, for example, it is more preferable to contain 85% by mass or more in the resin material constituting the tubular body.
Moreover, the resin material which comprises a pipe body may contain another additive.

The diameter (i.e., outer diameter) of the tubular body 12 is not particularly limited, but can be, for example, in the range of 10 mm to 100 mm, and preferably in the range of 12 mm to 35 mm. Moreover, the thickness of the tubular body 12 is not particularly limited, but, for example, 1.0 mm or more and 5.0 mm or less can be mentioned, and preferably 1.4 mm or more and 3.2 mm or less.

(Cover layer)
The covering layer 20 is tubular and covers the outer periphery of the tubular body 12 and the porous resin layer 14. The porous resin layer 14 is disposed between the tubular body 12 and the covering layer 20. The covering layer 20 is made of a resin material. Examples of the resin in the resin material constituting the coating layer 20 include polyolefins such as polybutene, polyethylene, polypropylene, and crosslinked polyethylene, and vinyl chloride, etc. Resins may be used alone or in combination of two or more. It is also good. Among them, low density polyethylene is suitably used, preferably containing low density polyethylene as a main component, for example, more preferably containing 80% by mass or more, and containing 90% by mass or more in the resin material constituting the coating layer. More preferable.

The MFR (Melt Flaw Rate) of the resin used is preferably 0.25 or more, more preferably 0.3 or more, and still more preferably 0.35 or more and 1.2 or less. By setting the MFR to 0.25 or more, the resin of the covering layer 20 can easily enter the porous structure of the porous resin layer 14. For this reason, the adhesion degree of the porous resin layer 14 mentioned later and the trough part 24 of the coating layer 20 can be raised. Further, by setting the MFR to 1.2 or less, burrs are less likely to occur. When the MFR is greater than 1.2, the molten resin can easily flow into the parting surface of the mold for forming the covering layer 20. This makes burrs more likely to occur. In addition, the resin material which comprises a coating layer may contain another additive.

As also shown in FIG. 2, the covering layer 20 is bellows-like, and has an annular peak 22 that is convex radially outward and an annular valley 24 that is concave radially outward. They are alternately and continuously formed in the axial direction S of the tubular body 12. The ridges 22 are disposed on the outer side in the radial direction R than the valleys 24. As shown in FIG. 3, assuming that the bellows-like outermost portion of the covering layer 20 is the outer wall 22A and the innermost portion in the radial direction is the inner wall 24A, the outer wall 22A and the inner wall 24A in the radial direction With the intermediate portion M as a boundary, the radially outer side is a peak 22, and the radially inner side is a valley 24.

The ridge portion 22 has an outer side wall 22A extending in the axial direction S and side walls 22B extending in the radial direction R from both ends of the outer side wall 22A. An outer bend 22C is formed between the outer wall 22A and the side wall 22B. The valley portion 24 has an inner side wall 24A extending in the axial direction S and side walls 24B extending in the radial direction R from both ends of the inner side wall 24A. An inner bent portion 24C is formed between the inner side wall 24A and the side wall 24B.

A concave crest space 23 is formed radially inward on the radially inner side of the crest 22 of the covering layer 20. In addition, it is preferable that the convex part 14B of the porous resin layer 14 mentioned later is inserted in the mountain space 23. As shown in FIG.

Moreover, although it does not specifically limit, it is preferable that the length L1 of axial direction S of the peak part 22 is set longer than the length L2 of axial direction S of the valley part 24. As shown in FIG. The length L1 is preferably 1.2 times or more of the length L2 in order to ensure the deformability of the outer wall 22A at the time of the shortening deformation described later.

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 of the mold for producing the covering layer 20 is too small. As a result, at the time of manufacturing the covering layer 20, when the resin constituting the covering layer 20 is extruded and then the resin is made uneven by the mold, the portion corresponding to the valley of the mold of the resin becomes thin and fragile Become. This is because the formation of the covering layer 20 becomes difficult. On the other hand, the length L1 is preferably 5 times or less of the length L2. This is because the flexibility of the composite tube 10 can be maintained by setting the length L1 to 5 times or less of the length L2. Moreover, when the length L1 is too long, when laying the composite pipe 10, the contact area with the ground becomes large and it becomes difficult to construct.

As shown in FIG. 3, the length L1 is the distance between the axial direction S outside of the surface of the covering layer 20 as viewed from the outside in the radial direction R at the portion intersecting the middle portion M in the covering layer 20 ( That is, it is the distance between the surface in the axial direction S on one side of the portion convex on the outside in the radial direction R of the covering layer 20 and the surface on the other side in the axial direction S). The length L2 is the distance between the axial direction S outside of the surface of the covering layer 20 seen from the inside in the radial direction R at a portion intersecting the middle portion M in the covering layer 20 (ie, the radial direction R of the covering layer 20 The distance between the surface on one side in the axial direction S of the portion to be convex inward and the surface on the other side in the axial direction S).

The thickness of the covering layer 20 is preferably 0.1 mm or more at the thinnest portion and 0.4 mm or less at the thickest portion in order to shorten the covering layer 20. The thickness H1 of the outer side wall 22A is smaller than the thickness H2 of the inner side wall 24A. The thickness H1 is preferably equal to or less than 0.9 times the thickness H2 in order to ensure the deformability of the outer side wall 22A at the time of the shortening deformation described later.

The difference in radius ΔR at the outer surfaces of the ridges 22 and the valleys 24 is preferably 800% or less of the average thickness of the covering layer 20. If the radius difference ΔR is large, the valleys 24 expand radially outward at the time of shortening even if the portion along the axial direction S of the ridges 22 is not deformed, or the adjacent ridges 22 do not approach each other It is hard to be distorted or distorted. When the radius difference ΔR is 800% or less of the average of the thickness of the covering layer 20, the length of the axial direction S of the peak 22 is set to It is preferred to be longer than the axial length. In addition, it is more preferable when it is 600% or less.

The diameter of the covering layer 20 (that is, the outer diameter of the outermost portion) is not particularly limited, but can be, for example, in the range of 13 mm or more and 130 mm or less.

(Porous resin layer)
The porous resin layer 14 is an example of the intermediate layer in the present disclosure, and is a layer formed 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, ethylene propylene diene rubber, and a mixture of these resins. Among them, polyurethane is preferable. The porous resin layer 14 is preferably a layer containing polyurethane as a main component (i.e., a porous urethane layer). For example, it is preferable to contain 80 mass% or more of polyurethane in the structural component of a porous resin layer, and it is more preferable to contain 90 mass% or more. The porous resin layer may contain other additives.

The abundance ratio of 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 K 6400-1 (2012), 25 / It is preferable that it is 25 mm or more, and 45 pieces / 25 mm or less are more preferable.
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 a composite pipe, a joint or the like is connected to the end of the inner pipe. At this time, it is required to shorten and shift the end of the covering layer to expose the end of the tube. However, when the coating layer is shifted, the porous resin layer may not follow and may be left behind on the outer surface of the tube, and the tube may not 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 appropriate flexibility. As a result, when the end of the covering layer is shortened and deformed to expose the end of the tube, the porous resin layer follows the movement of the covering layer well. For this reason, leaving on the outer surface of the tube is suppressed. As a result, the end of the tube can be easily exposed.

On the other hand, the porous resin layer has an appropriate strength because the density is 12 kg / m ³ or more, and the occurrence of breakage and breakage of the porous resin layer at the time of processing such as at the time of manufacturing the composite tube 10 is suppressed. Ru. The density of the porous resin layer is preferably 14 kg / m ³ or more and 20 kg / m ³ or less, more preferably 16 kg / m ³ , from the viewpoint of suppression of leaving to the outer surface of the tubular body and breakage and breakage during processing. More preferably, it is at least 18 kg / m ³ .

Here, the density of the porous resin layer can be measured by the method prescribed in JIS-K7222 (2005). The measurement environment is 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, but, for example, the existing ratio of pores in the porous resin layer (for example, the foaming ratio in the case of a foam) The method of adjusting, the method of adjusting the molecular structure of resin (namely, the molecular structure of the monomer used as the raw material of resin, and those crosslinked structures) etc. are mentioned.

The porous resin layer 14 is disposed between the tubular body 12 and the covering layer 20. The porous resin layer 14 is sandwiched between the inner side wall 24A of the valley portion 24 of the covering layer 20 and the tube 12. In addition, it is preferable to be further compressed by the inner side wall 24A and the pipe body 12 at the location where the sandwiching is performed, and the compression sandwiching portion 14A is formed.

The porous resin layer 14 is formed using a band-like porous resin sheet 14S, as shown in FIG. 12A. The porous resin layer 14 winds a porous resin sheet 14S formed in a band shape so as to have a width substantially equal to the outer peripheral length of the tubular body 12, around the tubular body 12 as shown in FIG. 12B. As will be described later, the resin composition to be the covering layer 20 is supplied to the outer periphery and molded.

When winding the porous resin sheet 14S around the tubular body 12, the end surface 14SA and the end surface 14SB on both sides in the width direction of the porous resin sheet 14S (direction of arrow W shown in FIGS. 12A and 12B) Wrap around. At this time, the butting position (the butting surface 14L) between the end surface 14SA and the end surface 14SB is wound so that the tubular body 12 is substantially linear along the axial direction of the tubular body 12 when viewed from the radial direction. When the end surface 14SA and the end surface 14SB are in contact with each other, the abutting surface 14L indicates the contact surface. However, the end surface 14SA and the end surface 14SB may not necessarily be in contact with each other. When the end surface 14SA and the end surface 14SB are separated from each other, the abutting surface 14L indicates a surface passing through the centers of the end surface 14SA and the end surface 14SB.

The thickness of the porous resin layer 14 is in the natural state (that is, in the state where a force such as compression or tension does not act, temperature 23.degree. C., relative humidity 45%), the outer periphery of the tubular body 12 and the inner wall 24A. It is preferable that the difference is greater than the difference with the radially inner surface, and it is further thicker than the difference.

In the compression sandwiching portion 14A, the porous resin layer 14 is thinner than the thickness in the natural state due to the compression. Between the adjacent compression pinching portions 14A of the porous resin layer 14, convex portions 14B are formed. The convex portion 14 </ b> B has a diameter larger than that of the compression holding portion 14 </ b> A and protrudes into the mountain space 23. When the porous resin layer 14 is compressed by the inner side wall 24A and the tubular body 12, the compression pinching portions 14A and the convex portions 14B are alternately and continuously formed in the axial direction S, and the outer periphery of the porous resin layer 14 The surface is wavy.

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

The length in the axial direction S in a natural state in which the porous resin layer 14 is extracted from between the tubular body 12 and the covering layer 20 is 90% or more and 100% or less of the length in the axial direction S of the covering layer 20 preferable. This is because, when the porous resin layer 14 is held in a stretched state between the tubular body 12 and the covering layer 20, the relative displacement between the porous resin layer 14 and the covering layer 20 when the covering layer 20 is shortened and deformed. This is because movement tends to occur, and it may occur that the outer peripheral end of the tubular body 12 can not be exposed without shortening of the porous resin layer 14. In order to suppress relative movement between the porous resin layer 14 and the covering layer 20, the length in the axial direction S of the porous resin layer 14 in the natural state is 90% to 100% of the length in the axial direction of the covering layer 20 It is preferable to set it as the following.

As a method of producing the composite tube 10, for example, the following method can be considered. Specifically, first, the porous resin sheet 14S constituting the porous resin layer 14 is wound around the outer periphery of the tubular body 12. Then, in this state, a melt of the resin composition for forming the coating layer 20 is further applied, and the outer peripheral surface of the melt has a semicircular arc inner surface and the inner surface has a bellows shape. A pair of molds are brought close to each other from two directions and brought into contact and solidified to form a bellows-like covering layer 20.

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 to this, and the porous resin layer 14 may be a multilayer. Examples of the composite tube in which the porous resin layer 14 is a multilayer include the composite tube 100 shown in FIG. 4 (a composite tube in which the porous resin layer 14 has 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 covering layer 20 are stacked in this order.

The inner circumferential surface of the porous resin layer 14 preferably covers the outer periphery of the tubular body 12 while being in full contact with the outer periphery of the tubular body 12. Here, “entirely in contact” does not mean that all parts need to be in intimate contact, but means that the entire surface is substantially in contact.

(Production method)
Next, a method of manufacturing the composite pipe 10 of the present embodiment will be described. In the method of manufacturing the composite tube 10, for example, the porous resin layer 14 is formed by winding the both ends of the porous resin sheet 14S opposite to each other on the outer periphery of the tube 12. Thereafter, the covering layer 20 is formed on the outer periphery of the porous resin layer 14.

For manufacturing the composite pipe 10, for example, a manufacturing apparatus 30 shown in FIG. 9 can be used. The manufacturing apparatus 30 includes an extruder 32, a die 34, a wave mold 36, a cooling tank 38, and a pulling device 39. In the manufacturing process of the composite pipe 10, the right side of FIG. 9 is the upstream side, and the pipe 12 is manufactured while moving from the right side to the left side. Hereinafter, this moving direction is referred to as a manufacturing direction Y. The die 34, the wave forming die 36, the cooling tank 38, and the pulling device 39 are disposed in this order with respect to the manufacturing direction Y, and the extruder 32 is disposed above the die 34.

Although not shown, a sheet-like member 15S is disposed upstream of the die 34. The tubular body 12 and a porous resin sheet 14S constituting the porous resin layer 14 are wound in a roll. By being pulled in the manufacturing direction Y by the pulling device 39, the tubular body 12 and the porous resin sheet 14S in a roll shape are continuously pulled out. As shown in FIG. 12B on the outer peripheral surface of the tubular body 12 drawn out continuously, the porous resin sheet 14S faces the end surface 14SA and the end surface 14SB, as shown in FIG. 12B. Wrapped around. The porous resin sheet 14S is slackened before the die 34 and is inserted into the die 34 in order to prevent application of tensile force. In FIG. 12B, the die 34 and the wave forming die 36 are not shown, but when the end face 14SA and the end face 14SB of the porous resin sheet 14S are inserted into the die 34 and the wave forming die 36. They are not in contact with each other and are separated from each other in the circumferential direction of the tube 12.

As shown in FIG. 9, on the outer periphery of the porous resin sheet 14S wound around the outer periphery of the tubular body 12, the resin material melted from the die 34 (that is, the melt of the resin composition for forming the coating layer 20) is It is extruded in a cylindrical shape and applied to form a resin material 20A. By setting the resin used here to low density polyethylene (LDPE) of MFR 0.25 or more, the resin material can easily enter the pores (bubbles) of the porous resin sheet, and the porous resin sheet 14S and the resin material 20A Adhesiveness is improved.

After the tubular extruded body 21 composed of the tubular body 12, the porous resin sheet 14S, and the resin material 20A is formed, a wave forming process (i.e., a bellows shape) is performed by the wave forming die 36 disposed downstream of the die 34. Process) is performed. The corrugating mold 36 is, for example, a pair of molds, and each mold has a semicircular inner surface, and an annular cavity 36A is formed in a portion corresponding to the ridge 22 of the covering layer 20 on the inner periphery thereof. An annular inner protrusion 36B is formed in a portion corresponding to the valley portion 24 and has a bellows shape. Each cavity 36A is formed with a suction hole 36C, one end of which is in communication with the cavity 36A and which penetrates the wave applying mold 36. In the cavity 36A, suction is performed from the outside of the wave forming die 36 through the suction holes 36C.

On the downstream side of the die 34, the corrugated die 36 is made to approach the resin material 20A from the left and right two directions so that the inner surfaces of the pair of dies come in contact with the resin material 20A. Then, the wave applying mold 36 covers the outer periphery of the tubular extruded body 21 and compresses the resin material 20A while compressing the resin material 20A by the inner projection 36B to form the resin material 20A, and the tubular extruded body together with the tubular body 12 and the porous resin sheet 14S. 21 is moved in the manufacturing direction Y. At this time, the inside of the cavity formed by the cavity 36A of the wave application mold 36 is sucked through the suction hole 36C by a suction device (not shown) to be a negative pressure. Thereby, the resin material 20A is deformed outward in the radial direction R and is formed by the cavity 36A, and the bellows-like shape in which the ridges 22 and the valleys 24 are alternately arranged along the axial direction S from the resin material 20A. The cover layer 20 is formed.

Here, when the resin material 20A is deformed to the outside in the radial direction R in the cavity 36A, the convex portion 14B of the porous resin sheet 14S deeply penetrates into the mountain space 23 (see the partial enlarged view shown in FIG. 9) It is locked in the mountain space 23. The compression sandwiching portion 14A of the porous resin sheet 14S is adhered to the inner side wall 24A of the valley portion 24 of the cover layer 20, and is compressed and sandwiched between the inner side wall 24A and the tubular body 12.

Moreover, as shown to FIG. 13A, in the state before mold clamping of the wave application mold 36 in a wave application process, the both end surfaces (namely, end surface 14SA and end surface 14SB) of the porous resin sheet 14S are in the circumferential direction of the pipe body 12. It is separated from each other. In order to return the porous resin sheet 14S to a belt-like shape shown in FIG. 12A, forces of separation from each other act on the end face 14SA and the end face 14SB. As a result, the resin material 20A is clamped in a state in which it is tensioned from the porous resin sheet 14S.

The separated 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 forming die 36 in the circumferential direction of the tube 12. Be done. The “position different from the parting surface 36D” refers to a position not overlapping the space sandwiched by the parting surfaces 36D of the pair of corrugated dies 36 in the circumferential direction of the tubular body 12.

At this time, it is preferable to arrange the opposing position V at a position farthest from the parting surface 36D. That is, it is preferable to dispose the facing position V at a position corresponding to the deepest portion of the cavity 36A (that is, a portion where the tangent is parallel to the parting surface 36D in the cavity 36A made semicircular in cross section).

In FIG. 13A, the outer peripheral surface of the tubular body 12 and the inner peripheral surface of the porous resin sheet 14S are drawn in contact with each other, but in the state before clamping the wave application mold 36. A gap is formed between the outer peripheral surface of the tubular body 12 and the inner peripheral surface of the porous resin sheet 14S. As a result, a separation space is formed between the end surface 14SA and the end surface 14SB without the end surface 14SA contacting the end surface 14SB.

Then, as shown in FIG. 13B, the corrugated die 36 is clamped to bring the parting surface 36D into contact. At this time, the gap (not shown) between the outer peripheral surface of the tubular body 12 and the inner peripheral surface of the porous resin sheet 14S is reduced, the end surface 14SA and the end surface 14SB are abutted, and the abutting surface 14L is formed. Ru.

In the present embodiment, since the facing position V of the end surface 14SA and the end surface 14SB is disposed at a position different from that of the parting surface 36D, the abutting surface 14L is different from the parting surface 36D of the wave forming die 36. Placed in position.

When the facing position V of the end face 14SA and the end face 14SB of the porous resin sheet 14S before clamping is disposed at a position farthest from the parting face 36D, the abutting face 14L in the axial direction of the tube 12 At least a portion is disposed at a position farthest from the parting surface 36D in the circumferential direction of the tube 12.

A parting line PL (see FIG. 1) is formed at a position corresponding to the parting surface 36D on the outer peripheral surface of the bellows-like covering layer 20 formed when the wave application mold 36 is clamped. The parting line PL may or may not be visible depending on the accuracy of the mold, the fluidity of the resin, the presence or absence of a post-process such as polishing, but the parting line in the present disclosure may or may not be visible. Point to both.

The coating layer 20 is cooled in the cooling bath 38 after the wave application process is performed in the wave application mold 36. Thus, the composite pipe 10 is manufactured.

(Action)
The operation of the composite pipe 10 described above and the method of manufacturing the composite pipe 10 will be described. In the composite pipe 10 according to the above embodiment, as shown in FIG. 1, both end faces (that is, the end face 14SA and the end face 14SB) in the width direction of the band-like porous resin sheet 14S between the pipe body 12 and the covering layer 20 The porous resin layer 14 formed in a tubular shape is disposed in a state in which it is pressed. The parting line PL of the covering layer 20 and the abutting position (abutment surface 14L) of the porous resin sheet 14S are disposed at different positions in the circumferential direction of the tubular body 12.

That is, as shown in FIGS. 13A and 13B, when forming the coating layer 20 on the outer periphery of the porous resin layer 14 using the wave applying die 36, the parting surface 36 D of the wave applying die 36 is The porous resin sheet 14S is disposed in a state where the opposing positions V of both end surfaces in the width direction (that is, the end surface 14SA and the end surface 14SB) are shifted. Then, along with the mold clamping, as shown in FIG. 13B, the end face 14SA and the end face 14SB are abutted at a position different from the parting surface 36D of the wave forming die 36, and the abutting surface 14L is formed.

At the time of mold clamping, as shown in FIG. 14, the end faces 14SA and the end faces 14SB opposed to each other are moved toward each other and pushed against each other. Therefore, in the resin material 20A covering the outer periphery of the porous resin sheet 14S, the slack portion 20T is formed in the vicinity of the end face 14SA and the end face 14SB.

At this time, the end surface 14SA and the end surface 14SB of the porous resin sheet 14S are abutted at positions different from the parting surface 36D (see FIG. 13A) of the wave application die 36. For this reason, the slack portion 20T is pressed by the cavity 36A of the corrugated die 36 and disappears. In addition, since the end face 14SA and the end face 14SB of the porous resin sheet 14S are not disposed at the position corresponding to the parting surface 36D of the corrugated die 36, the slack portion 20T is difficult to be formed. Thereby, the slack portion 20T pinched by the parting surface is less likely to occur. Therefore, burrs are less likely to occur in the covering layer 20.

Further, in the composite pipe 10 according to the present embodiment, as shown in FIG. 13B, at least a part of the abutting surface 14L of the porous resin sheet 14S in the axial direction of the tubular body 12 (the front and back direction in FIG. In the circumferential direction of the pipe body 12, it is arrange | positioned most distantly from the parting surface 36D.

When the wave application mold 36 is clamped, the resin material 20A and the porous resin sheet 14S may be partially moved in the circumferential direction of the tubular body 12 by receiving an external force from the mold 36. In such a case, the abutting surface 14L is partially offset in the circumferential direction from the other portions. Since at least a part of the abutting surface 14L is disposed at a position farthest from the parting surface 36D in the circumferential direction of the tube 12, even if the abutting surface 14L is partially displaced and arranged, It is suppressed that the portion is arranged at the same position as the parting surface 36D. This can suppress the occurrence of burrs.

In addition, the state before mold clamping of the composite tube which concerns on a comparative example is shown by FIG. 15A. In the composite pipe according to the comparative example, the porous resin sheet 14S is in a state in which the facing positions V of both end faces in the width direction (that is, the end face 14SA and the end face 14SB) coincide with the parting face 36D of the corrugated die 36 Will be placed. In other words, in the circumferential direction of the tube 12, the gap (facing position V2) between the parting surfaces 36D facing each other in the pair of corrugated dies 36 and the gap (facing position V) between the end face 14SA and the end face 14SB overlapping. Therefore, as shown in FIG. 15B, the end face 14SA and the slack portion 20T generated in the resin material 20A near the end face 14SB are sandwiched by the parting surface 36D. Thereby, a burr may occur in the coating layer of the composite tube according to the comparative example.

When connecting the composite pipe 10 according to this embodiment and the joint, the force in the direction in which the covering layer 20 is shortened in the axial direction S to expose the pipe body 12 with respect to the covering layer 20 in the state shown in FIG. To work. Thereby, as shown in FIG. 5, the covering layer 20 at one end moves in the direction in which the tubular body 12 is exposed.

In the outer wall 22A of the ridge 22 and the inner wall 24A of the valley 24, the length L1 in the axial direction S is preferably longer than L2, and the thickness H1 is preferably thinner than H2. As a result, the outer side wall 22A is more easily deformed than the inner side wall 24A, and as shown in FIG. 6, the outer side wall 22A deforms so as to bulge radially outward. Subsequently, as shown in FIG. 7, the outer bending portion 22C of the peak portion 22 and the inner bending portion 24C of the valley portion 24 are deformed such that the adjacent peak portions 22 approach each other. In this way, as shown in FIG. 5, the covering layer 20 at one end is more likely to move in the direction in which the tube 12 is exposed. As described above, when the covering layer 20 is shortened, the outer wall 22A is deformed so as to expand, so that the valley portion 24 is in the radial direction even if the bending angle and thickness of the covering layer 20 have some variations. It is possible to suppress outward bulging or a distorted deformation state in which adjacent mountain portions 22 do not approach each other. Thereby, the fall of the shortened external appearance of the coating layer 20 can be suppressed.

The porous resin layer 14 is preferably compressed by the inner side wall 24A and the tube 12. The compression pinching portion 14A is in close contact with the covering layer 20, and the convex portion 14B is adjacent to the side wall 24B of the valley portion 24. It is easier to engage and shorten with the covering layer 20. Thereby, as shown in FIG. 8, the end of the tube 12 can be exposed.

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

Moreover, in this embodiment, although the outer side wall 22A is made into substantially linear shape along the axial direction S, it is good also as arc shape bulging outward in the radial direction. Furthermore, the inner side wall 24A may have an arc shape which bulges radially inward.

Further, in the present embodiment, it is preferable that the porous resin layer 14 be compressed by the inner side wall 24A and the tubular body 12. As a result, the compression sandwiching portion 14A is in close contact with the covering layer 20, and the convex portion 14B is engaged between the side walls 24B of the adjacent valleys 24. Therefore, the porous resin layer 14 can easily follow by the movement of the coating layer 20, and the porous resin layer 14 can be prevented from being left behind on the outer periphery of the tubular body 12 and 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. Therefore, after the tube 12, the porous resin layer 14 and the covering layer 20 are moved relative to each other to expose the end of the tube 12, the space between the outer periphery of the tube 12 and the inner periphery of the porous resin layer 14 As a result, the porous resin layer 14 and the covering layer 20 can be easily held in the shortened position.

Further, in the present embodiment, the compression sandwiching portion 14A of the porous resin layer 14 is in close contact with the covering layer 20, and the convex portions 14B are engaged between the side walls 24B of the adjacent valley portions 24. Therefore, the porous resin layer 14 can easily follow the movement of the coating layer 20, and the porous resin layer 14 can be prevented from being left behind on the outer periphery of the tubular body 12, and can be easily shortened together with the coating layer 20. .

(Low friction resin layer)
In addition, although the composite pipe 10 in the said embodiment is equipped with the pipe body 12, the porous resin layer 14, and the coating layer 20, and the pipe body 12 is directly covered by the porous resin layer 14, implementation of this indication is carried out. The form is not limited to this. For example, as shown in FIG. 11, the low friction resin layer 13 may be interposed between the tubular body 12 and the porous resin layer 14.

The low friction resin layer 13 is made of a resin material, and is a layer whose slip resistance value on the inner circumferential surface is smaller than the slip resistance value on the inner circumferential surface of the porous resin layer 14. Examples of the low friction resin layer 13 include a sheet-like resin sheet layer. As resin in the resin material which constitutes low friction resin layer 13, polyester, nylon, polyolefin (for example, polyethylene, polypropylene, polybutene etc.) etc. are mentioned, for example.

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

The form of the low friction resin layer 13 is, for example, non-woven fabric (for example, melt blow, spun bond, etc.), knitted fabric (for example, russell, tricot, milanese etc.), woven fabric (eg, plain weave, twill weave, imitation twill weave, twill weave, entanglement) And the like), films and the like.

Among these, the low-friction resin layer 13 is, among these, polyester non-woven fabric (that is, non-woven fabric containing polyester as a main component), polyester tricot (that is, tricot knitted fabric containing polyester as a main component), nylon non-woven fabric (that is, nylon as a main component) Nonwovens containing nylon), nylon tricots (i.e., knits containing nylon as a main component), polyethylene films (i.e., films containing polyethylene as a main component), etc. are preferred, and polyester non-wovens and nylon tricots are more preferred.

Also, if the low-friction resin layer 13 is a nonwoven fabric, the basis weight of the nonwoven fabric, for example 10 g / ^{m 2} or more 500 g / ^{m 2} or less can be mentioned, 12 g / ^{m 2} or more 200 g / ^{m 2} or less is preferable, 15 g / m ² or more and 25 g / m ² or less are more preferable.

The sliding resistance value (unit: N) on 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 on the inner peripheral surface of the porous resin layer 14. And preferably 12 or more and 23 or less.

The sliding resistance value (unit: N) on the inner peripheral surface of the low friction resin layer 13 is, for example, 0.36 or more times the sliding resistance value (unit: N) on the inner peripheral surface of the porous resin layer 14. 90 times or less is mentioned, 0.44 or more and 0.85 times or less are preferable.

The inner circumferential surface of the low friction resin layer 13 preferably covers the outer periphery of the tube 12 while being in full contact with the outer periphery of the tube 12. Here, “entirely in contact” does not mean that all parts need to be in intimate contact, but means that the entire surface is substantially in contact. Therefore, for example, the porous resin layer 14 and the low friction resin layer 13 are a sheet-like first sheet (hereinafter also referred to as a “porous resin sheet”) constituting the porous resin layer 14, and the low friction resin layer 13. When the sheet-like second sheet (hereinafter, also referred to as "low-friction resin sheet") is formed by winding a laminate, the joint portion is partially separated or the tube 12 and the coating are covered The case where the part which became wrinkles with the layer 20 is partially separated is included.

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 and 3 mm or less, from the viewpoint of followability to the coating layer. . In addition, let the thickness of the low friction resin layer 13 take out the low friction resin layer 13 from the composite pipe | tube 10, and let it be an average value of the value obtained by measuring three arbitrary places.

The composite tube 10 provided with the low friction resin layer 13 has the low friction resin layer 13 disposed between the tube body 12 and the porous resin layer 14, thereby shortening and deforming the end of the coating layer 20. When the coating layer 20 is returned after the end of the tubular body 12 is exposed, the porous resin layer 14 is prevented from being involved. Specifically, it is as follows.

In a composite tube having the tube body 12, the porous resin layer 14, and the bellows-like covering layer 20, when connecting a joint or the like to the end of the inner tube body 12, as shown in FIG. The part is shortened in the direction indicated by arrow B and shifted to expose the end of the tube, and the end of the tube is connected to a joint etc. and then the shortened covering layer is extended in the direction indicated by arrow A to It is required 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 tubular body 12 and the porous resin layer 14, the sliding resistance value on the inner peripheral surface of the low friction resin layer 13 is Small and slippery. Therefore, when the end of the covering layer 20 is shortened and deformed to expose the end of the tubular body 12 and then the covering layer is put back again, the porous resin layer 14 and the low friction resin layer 13 form the covering layer 20. The end of the tubular body 12 exposed can be well covered by the low friction resin layer 13, the porous resin layer 14, and the covering layer 20 well following the operation of axial extension.

Here, the "slip resistance value" is specifically measured as follows. In the case of measuring the sliding resistance value on the inner circumferential surface of the low friction resin layer, first, the covering layer is disposed on the outer peripheral side of the tube, and the porous resin layer and the sliding resistance value are set between the tube and the covering layer. A low friction resin layer to be measured is inserted so that the low friction resin layer is in contact with the tube to form a composite tube having a length of 200 mm. Then, connect one end of the composite pipe to the tip of a force gauge (for example, IMADA popular digital force gauge DS2) and shift the coating layer at the other end of the composite pipe by 50 mm (unit: N) Measure).

In addition, in the case of measuring the sliding resistance value on the inner peripheral surface of the porous resin layer, the covering layer is disposed on the outer peripheral side of the tubular body, and the porosity of the target of measuring the sliding resistance value between the tubular body and the covering layer. The porous resin layer is inserted such that the porous resin layer is in contact with the tube to form a composite tube 200 mm in length. Then, the sliding resistance value of the porous resin layer is measured in the same manner as the measurement of the sliding resistance value of the low friction resin layer.

When the low friction resin layer 13 is provided, the thickness of the porous resin layer 14 in the natural state is preferably thicker than the thickness of the low friction resin layer 13. The porous resin layer 14 preferably has a role of heat protection in the composite tube 10, and the heat protection property is improved as the porous resin layer 14 is thicker. On the other hand, when the low friction resin layer 13 is too thick, the followability to the coating layer 20 in the porous resin layer 14 and the low friction resin layer 13 is reduced. Therefore, by making the porous resin layer 14 relatively thick and making the low friction resin layer 13 relatively thin, both the heat protection property and the followability to the coating layer 20 are improved.

Furthermore, from the viewpoint of heat protection and coverage to the covering layer, the thickness of the porous resin layer 14 in the natural state is preferably 10 times to 200 times the thickness of the low

friction resin layer

13, and 20 times More than 150 times is more preferable, and 25 times or more and 100 times or less is more preferable.

The inner peripheral surface of the porous resin layer 14 is preferably bonded to the outer peripheral surface of the low friction resin layer 13. By adhering the porous resin layer 14 and the low friction resin layer 13, the followability to the coating layer of the porous resin layer 14 and the low friction resin layer 13 is further improved.

As a method of bonding the porous resin layer 14 and the low friction resin layer 13, in addition to a method of applying and bonding an adhesive between the two layers, a method of bonding by a frame laminating method can be mentioned. The lamination method is preferred. That is, it is preferable that the porous resin layer 14 and the low friction resin layer 13 be a frame laminate adhesive body.

The frame laminating method is a method in which, for example, a soluble substance contained in the porous resin layer 14 is thermally melted and exfoliated by a flame, and the exuded melt adheres to the low friction resin layer 13. Then, a laminate (hereinafter, also referred to as a "glare adhesive") in which the porous resin layer 14 and the low-friction resin layer 13 are bonded by the frame laminating method is coated with an adhesive between the two layers to form a porous resin. Unlike a laminate in which the layer 14 and the low-friction resin layer 13 are adhered (hereinafter also referred to as “adhesive by an adhesive”), both layers between the porous resin layer 14 and the low-friction resin layer 13 are adhered Layers can be thinned. Therefore, in addition to the followability to the coating layer in the porous resin layer 14 and the low friction resin layer 13 being further improved, the composite tube 10 having the flash adhesive is less likely to generate burrs in the process of manufacturing the composite tube 10 .

Second Embodiment
Hereinafter, a second embodiment which is an example of a composite pipe according to the present disclosure will be described in detail with reference to the drawings as appropriate. In addition, about the structure similar to 1st Embodiment, it shows with the same code | symbol, and abbreviate | omits description suitably. Further, regarding the manufacturing method, the description of the same contents as those of the first embodiment will be appropriately omitted.

(Porous resin layer)
The porous resin layer 14 in the second embodiment is formed using a band-like porous resin sheet 14S, as shown in FIG. 12A, as in the first embodiment. The porous resin layer 14 winds a porous resin sheet 14S formed in a band shape so as to have a width substantially equal to the outer peripheral length of the tubular body 12, around the tubular body 12 as shown in FIG. 12B. The end face 14SA and the end face 14SB are fused. Then, in this state, a melt of the resin composition for forming the coating layer 20 is further applied, and the outer peripheral surface of the melt has a semicircular arc inner surface and the inner surface has a bellows shape. A pair of molds are brought close to each other from two directions and brought into contact and solidified to form a bellows-like covering layer 20.

(Production method)
In the method of manufacturing the composite pipe 10 according to the second embodiment, for example, both end faces of the porous resin sheet 14S are wound opposite to each other on the outer periphery of the pipe body 12, and both end faces are fused to form the porous resin layer 14 Do. Thereafter, the covering layer 20 is formed on the outer periphery of the porous resin layer 14.

For example, a manufacturing apparatus 30 shown in FIG. 16 can be used to manufacture the composite pipe 10. The manufacturing apparatus 30 includes an extruder 32, a die 34, a wave mold 36, a cooling tank 38, and a pulling device 39. In the manufacturing process of the composite pipe 10, the right side of FIG. 16 is the upstream side, and the pipe 12 is manufactured while moving from the right side to the left side. Hereinafter, this moving direction is referred to as a manufacturing direction Y. The die 34, the corrugated die 36, the cooling tank 38, and the pulling device 39 are disposed in this order with respect to the manufacturing direction Y, and the extruder 32 is disposed upstream of the die 34. Further, on the upstream side of the extruder 32, a heat gun or cartridge heater (not shown) or both the heat gun and the cartridge heater are installed, and the position shown by the arrow H in FIG. 16, ie, the end surface 14SA of the porous resin sheet 14S The end face 14SA and the end face 14SB can be fused by applying hot air or the like to the abutting face 14L with the end face 14SB. In the following description, the fusion-bonded abutting surface 14L may be referred to as a fusion-bonded surface 14R.

Although not shown, a sheet-like member 15S is disposed upstream of the die 34. The tubular body 12 and a porous resin sheet 14S constituting the porous resin layer 14 are wound in a roll. By being pulled in the manufacturing direction Y by the pulling device 39, the tubular body 12 and the porous resin sheet 14S in a roll shape are continuously pulled out. As shown in FIG. 12B on the outer peripheral surface of the tubular body 12 drawn out continuously, the porous resin sheet 14S faces the end surface 14SA and the end surface 14SB, as shown in FIG. 12B. Wrapped around. The porous resin sheet 14S is inserted into the die 34 in a state where the end face 14SA and the end face 14SB are fused by the heat gun.

As shown in FIG. 16, on the outer periphery of the porous resin sheet 14S wound around the outer periphery of the tubular body 12 and fused at both ends, a resin material melted from the die 34 (ie, a resin for forming the coating layer 20) The molten material of the composition is cylindrically extruded and applied to form a resin material 20A. By setting the resin used here to low density polyethylene (LDPE) of MFR 0.25 or more, the resin material can easily enter the pores (bubbles) of the porous resin sheet, and the porous resin sheet 14S and the resin material 20A Adhesiveness is improved.

After the tubular extruded body 21 composed of the tubular body 12, the porous resin sheet 14S, and the resin material 20A is formed, a wave forming process (i.e., a bellows shape) is performed by the wave forming die 36 disposed downstream of the die 34. Process) is performed. The corrugation process is the same as in the first embodiment, and thus the description thereof is omitted.

As shown in FIG. 17A, the fusion bonding surface 14R 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 application mold 36 in the circumferential direction of the tube 12. Ru.

At this time, it is preferable that the fusion bonding surface 14R be disposed at a position farthest from the parting surface 36D. That is, it is preferable to dispose the fusion surface 14R at a position corresponding to the deepest portion of the cavity 36A (that is, a portion where the tangent is parallel to the parting surface 36D in the cavity 36A which is semicircular in cross section).

A parting line PL (see FIG. 1) is formed at a position corresponding to the parting surface 36D on the outer peripheral surface of the bellows-like covering layer 20 formed when the wave application mold 36 is clamped.

When the coating layer 20 is formed into a bellows shape using the wave application mold 36, the coating layer 20 is cooled using the cooling tank 38, and the bellows-shaped coating layer 20 is completed, and the composite tube 10 is manufactured. . The composite pipe 10 is continuously conveyed in the manufacturing direction Y by using the pulling device 39, and the manufacturing pipe 30 continuously manufactures the composite pipe 10.

(Action)
The operation of the composite pipe 10 described above and the method of manufacturing the composite pipe 10 will be described. In the composite pipe 10 according to the above embodiment, as shown in FIG. 1, both end faces in the width direction of the strip-like porous resin sheet 14S (that is, the end face 14SA and the end face 14SB) A porous resin layer 14 formed in a tubular shape in a fused state is disposed. The parting line PL of the covering layer 20 and the fusion bonding surface 14R between the end surface 14SA of the porous resin sheet 14S and the end surface 14SB are disposed at different positions in the circumferential direction of the tubular body 12.

That is, as shown in FIG. 16, a resin material (resin material 20A) for forming the covering layer 20 on the outer periphery of the porous resin sheet 14S in a state where the end surface 14SA and the end surface 14SB of the porous resin sheet 14S are fused. Is applied. And as shown to FIG. 17A and FIG. 17B, in the state by which end surface 14SA and end surface 14SB of porous resin sheet 14S were fused, a covering layer is carried out to the perimeter of porous resin layer 14 using corrugating mold 36. 20 are formed. In addition, the porous resin sheet 14S is disposed with the fusion bonding surface 14R shifted with respect to the parting surface 36D of the wave application mold 36.

By the way, the state before mold clamping of the composite pipe which concerns on a comparative example is shown by FIG. 15A. 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 face 14SA and the end face 14SB) are not fused. For this reason, when the porous resin sheet 14S tries to return to the original shape, a gap is formed between both end faces. Further, the end surface 14SA and the end surface 14SB are disposed in a state where the facing position V of the end surface 14SA and the end surface 14SB coincide with the parting surface 36D of the wave forming die 36. In other words, in the circumferential direction of the tube 12, the gap (facing position V2) between the parting surfaces 36D facing each other in the pair of corrugated dies 36 and the gap (facing position V) between the end surface 14SA and the end surface 14SB overlap ing.

As a result, as shown in FIG. 15B, the end face 14SA and the end face 14SB move in a direction in which the end face 14SA and the end face 14SB approach each other as the mold is tightened, and a slack portion 20T is generated near the end face 14SA and the end face 14SB of the resin material 20A. When the slack portion 20T is sandwiched by the parting surface 36D, burrs may occur in the covering layer.

On the other hand, in the composite pipe 10 according to the embodiment of the present disclosure, as shown in FIG. 17A, the end face 14SA and the end face 14SB of the porous resin sheet 14S are fused. Even if the mold is clamped, the slack portion 20T (see FIG. 15B) does not easily occur in the resin material 20A. For this reason, it is hard to generate | occur | produce a burr | flash in the coating layer 20. As shown in FIG.

Furthermore, in the composite pipe 10, the fusion bonding surface 14R of the porous resin sheet 14S is disposed offset with respect to the parting surface 36D of the wave application mold 36. For this reason, as shown in FIG. 14, even when there is a portion where the end face 14SA and the end face 14SB are not partially fused, the slack portion 20T generated in the resin material 20A of the part is the corrugated die 36. Is pressed by the cavity 36A and disappears. For this reason, it is hard to generate | occur | produce a burr | flash in the coating layer 20. As shown in FIG.

Thus, “the state in which both end surfaces in the width direction of the porous resin sheet 14S (that is, the end surface 14SA and the end surface 14SB) are fused” in the present disclosure means the end surface 14SA and the end surface 14SB in the axial direction of the tube 12. Shall be included if not partially fused.

Further, in the composite pipe 10 according to the present embodiment, as shown in FIG. 17B, at least a part of the fusion surface 14R of the porous resin sheet 14S in the axial direction of the tubular body 12 (the front and back direction of FIG. 17B) In the circumferential direction of the pipe body 12, it is arrange | positioned most distantly from the parting surface 36D.

When the wave application mold 36 is clamped, the resin material 20A and the porous resin sheet 14S may be partially moved in the circumferential direction of the tubular body 12 by receiving an external force from the mold 36. In such a case, the fusion bonding surface 14R is partially offset in the circumferential direction from other portions. By arranging at least a part of the fusion bonding surface 14R at a position farthest from the parting surface 36D in the circumferential direction of the tube 12, even if the fusion bonding surface 14R is partially displaced and arranged, It is suppressed that the portion is arranged at the same position as the parting surface 36D. This can suppress the occurrence of burrs.

In the composite pipe 10 in the present embodiment, the fusion bonding surface 14R of the porous resin sheet 14S is disposed to be shifted with respect to the parting surface 36D of the wave application mold 36, but the embodiment of the present disclosure Is not limited to this. For example, the fusion bonding surface 14R of the porous resin sheet 14S may be disposed at a position corresponding to the gap (opposing position V2) between the parting surfaces 36D facing each other in the pair of corrugated dies 36. Even when arranged in this manner, the slack portion 20T is unlikely to be generated in the resin material 20A of the portion.

The disclosures of Japanese patent application 2017-238864 filed on Dec. 13, 2017 and Japanese patent application 2017-238865 filed on Dec. 13, 2017 are hereby incorporated by reference in their entirety. It is captured. All documents, patent applications and technical standards described herein are as specific and individually as individual documents, patent applications and technical standards are incorporated by reference. Incorporated herein by reference.

Claims

With a tubular tube,
An annular ridge which is tubular and covers the outer periphery of the tube and which is convex radially outward and an annular valley which is concave outward in the radial direction are alternately formed in the axial direction of the tube. A bellows-like covering layer made of a resin material,
It is formed in a tubular shape in a state in which both end faces in the width direction of the strip-like porous resin sheet are abutted, and it is disposed between the tubular body and the covering layer, and sandwiched between the valley portion and the tubular body An intermediate layer in which the abutting positions of the both end surfaces and the parting line of the covering layer are disposed at different positions in the circumferential direction of the tube;
Composite tube with.
With a tubular tube,
An annular ridge which is tubular and covers the outer periphery of the tube and which is convex radially outward and an annular valley which is concave outward in the radial direction are alternately formed in the axial direction of the tube. A bellows-like covering layer made of a resin material,
Both end faces in the width direction of the strip-like porous resin sheet are formed into a tubular shape in a fused state, and are disposed between the tubular body and the covering layer, and sandwiched between the valley portion and the tubular body The middle layer,
Composite tube with.
The composite pipe according to claim 1, wherein the abutting position is disposed at a position farthest from the parting line of the covering layer in the circumferential direction of the pipe body.
The composite pipe according to any one of claims 1 to 3, wherein Melt flow rate (MFR) of the resin material forming the covering layer is 0.25 or more and 1.2 or less.
A step of facing and winding the both end faces of the strip-like porous resin sheet around the outer periphery of the annular tube;
Applying a resin material to the outer periphery of the porous resin sheet;
The tubular body, the porous resin sheet and the resin material are disposed in the mold and clamped in a state where the opposing positions of the both end faces are offset from the parting surface of the mold, and the both end faces are pressed Forming an intermediate layer, and forming a coating layer formed of the resin material on the outer periphery of the intermediate layer;
A method of manufacturing a composite pipe having:
A step of facing and winding the both end faces of the strip-like porous resin sheet around the outer periphery of the annular tube;
Fusing the two end faces;
Applying a resin material to the outer periphery of the porous resin sheet;
The tubular body, the porous resin sheet and the resin material are placed in a mold and clamped, and both end faces are pressed to form an intermediate layer, and the resin material is molded on the outer periphery of the intermediate layer Forming a covering layer;
A method of manufacturing a composite pipe having: