JP2019105320A - Composite tube - Google Patents

Abstract

To improve heat insulation performance of a composite tube.SOLUTION: A composite tube 10 includes: a coating layer 20 which has a tubular form into which a tube body can be inserted, is formed into a bellows shape by forming annular crest parts 22 protruding to the radial outer side and annular trough parts 24 recessed on the radial outer side alternately in an axial direction, and is made of a resin material; and a skin layer 30 which covers an outer periphery of the coating layer 20 to thermally insulate the coating layer 20 in at least one area of the coating layer 20 as seen in the axial direction and can expand or contract along the axial direction of the coating layer 20.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a 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, Patent Document 1 below describes a corrugated pipe in which an outer pipe provided with an annular ridge is disposed on the outer circumference of an inner pipe.

Unexamined-Japanese-Patent No. 2004-322583

  In the corrugated pipe shown in the patent document 1, the valley portion of the outer pipe is in close contact with the inner pipe. For this reason, the inner pipe is susceptible to the temperature environment outside the outer pipe. In addition, the temperature is easily transmitted from the inner pipe to the outside of the outer pipe.

  An object of the present invention is to improve the heat retention of a composite tube in consideration of the above-mentioned facts.

  The composite pipe according to claim 1 is formed into a tubular shape in which the tubular body can be inserted, and an annular peak which is convex outward in the radial direction and an annular valley which is concave in the outer radial direction are alternately alternated in the axial direction A cover layer formed of a resin material and formed into a bellows shape, and covering the outer periphery of the cover layer to thermally insulate the cover layer in at least a partial region in the axial direction of the cover layer And a skin layer which is stretchable along the axial direction of the covering layer.

  In the composite tube of claim 1, the outside of the covering layer is thermally insulated by the skin layer. Therefore, the heat retaining property of the composite pipe can be enhanced. Thus, the tube inserted into the composite tube can be kept warm. For this reason, the heat retaining property of the composite tube is high as compared with the case without the epidermal layer. In addition, the covering layer is formed in a bellows shape, and the skin layer is stretchable along the axial direction. For this reason, when connecting the tube body to be inserted, etc., it is possible to extend and contract the covering layer and the skin layer integrally.

  The composite pipe of claim 2 is the composite pipe of claim 1, wherein an air pool is formed between the valley and the skin layer.

  In the composite pipe of claim 2, an air reservoir is formed between the valley portion and the skin layer. For this reason, compared with the case where the space between the valley portion and the skin layer is filled with, for example, a substance whose specific heat is smaller than that of air, the heat insulating property of the coating layer is enhanced.

  The composite pipe according to claim 3 is the composite pipe according to claim 1 or 2, wherein the skin layer is bellows-shaped.

  In the composite pipe according to claim 3, the outer skin layer can be expanded and contracted in the axial direction by being formed into a bellows shape. In addition, since the air can be held inside the peak portion of the bellows, the coating layer can be thermally insulated.

  The composite pipe according to claim 4 is, in the composite pipe according to any one of claims 1 to 3, disposed between the pipe inserted in the covering layer, the pipe and the covering layer. And an intermediate layer formed of a porous resin and held between the valley and the tubular body.

  The composite tube of claim 4 comprises an intermediate layer formed of a porous resin between the tube and the covering layer. For this reason, the heat retention effect of the tubular body is enhanced as compared with the case without the porous resin layer.

  According to the present invention, it is possible to enhance the heat retention of the composite tube.

It is a perspective view showing a compound pipe concerning an embodiment of the present invention. It is a longitudinal section showing a compound pipe concerning an embodiment of the present invention. It is a longitudinal cross-section partial enlargement of a compound pipe concerning an embodiment of the present invention. It is a perspective view showing the compound tube concerning other embodiments of the present invention. It is a longitudinal cross-sectional view which shows the state by which the edge part of the pipe | tube body of the composite pipe | tube which concerns on embodiment of this invention was exposed. It is a figure which shows the process in which a skin layer, a coating layer, and a porous resin layer are shortened and deformed in the longitudinal cross-section part of FIG. It is a figure which shows the state by which the skin layer, the coating layer, and the porous resin layer were shortened and deformed in the longitudinal cross-section part of FIG. It is a perspective view showing the state where the end of a tube of a compound tube concerning an embodiment of the present invention was exposed. (A) is a longitudinal cross-sectional view which shows the modification which filled the resin, without forming an air pool between a coating layer and a skin layer in the composite tube of this invention, (B) forms a skin layer in a bellows shape. It is a longitudinal section showing a modified example. In a composite tube having a tubular body, a porous resin layer, a bellows-like coating layer, and a skin layer, the force acting on the porous resin layer from the coating layer acts from the tubular body when restoring the shortened deformed coating layer. It is a longitudinal cross-sectional view for demonstrating force. The composite pipe | tube which concerns on embodiment of this invention WHEREIN: It is a longitudinal cross-sectional view which shows the modification which provided the low friction resin layer.

  Hereinafter, an embodiment which is an example of a composite pipe according to the present invention will be described in detail with reference to the drawings as appropriate. Components indicated by the same reference numerals in the drawings mean that they are the same components. Note that duplicate explanations and symbols in the embodiments described below may be omitted. In addition, this invention is not limited to the following embodiment at all, Within the range of the objective of this invention, a change can be added suitably and can be implemented.

  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 invention comprises a tubular tube, a covering layer which is tubular and covers the outer periphery of the tube, a skin layer covering the outer periphery of the covering layer, and is disposed between the tube and the covering layer And a porous resin 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 skin layer is formed of an axially stretchable elastomer. The porous resin layer is disposed so as to be sandwiched between the valley and the tube.

  Next, an embodiment of the composite tube of the present invention will be described based on the drawings. 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 (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 Flow Rate) of the resin used is preferably 0.25 or more, more preferably 0.35 or more, and still more preferably 0.4 or more and 1.2 or less. By setting the MFR to 0.25 or more, the resin of the cover layer 20 can easily enter the porous structure of the porous resin layer 14, and the adhesion between the porous resin layer 14 and the valleys 24 of the cover layer 20 described later Can be enhanced. Further, by setting the MFR to 1.2 or less, burrs are less likely to occur. When MFR is larger than 1.2, the molten resin easily flows into the parting surface of the mold for forming the covering layer 20, and burrs are easily generated. 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, and the resin constituting the covering layer 20 is extruded at the time of producing the covering layer 20 When the resin is made uneven with the mold, the portion of the resin corresponding to the valley of the mold becomes thin and fragile, which makes it difficult to form the covering layer 20. 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 ( It is the distance between the surface in the axial direction S on one side of the portion to be convex outward 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 viewed from the inside in the radial direction R at the portion intersecting the middle portion M in the covering layer 20 (the radial direction R of the covering layer 20 It is the distance between the surface in the axial direction S on one side 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 effective to make it longer than the axial length. In addition, when it is 600% or less, it is more effective.

  Although it does not specifically limit as a diameter (outer diameter of the outermost part) of the coating layer 20, For example, it can be set as the range of 13 mm or more and 130 mm or less.

(Skin layer)
The skin layer 30 is arranged to cover the outer periphery of the covering layer 20 along the axial direction S of the covering layer 20, as shown in FIG. The skin layer 30 is formed by a tubular cover having a finite length along the axial direction of the covering layer 20, and is disposed over substantially the whole of the covering layer 20. When the cover forming the skin layer 30 is shorter than the covering layer 20, the ends of the cover are placed one on top of the other.

  As shown in FIG. 3, the inner circumferential surface of the skin layer 30 is disposed in intimate contact with the outer side wall 22A of the ridge portion 22 in the covering layer 20. As the elastomer forming the skin layer 30, it is preferable to use one that is softer than the resin material forming the covering layer. That is, when the covering layer 20 is shortened along the axial direction S as shown in FIG. 5, it is preferable to have elasticity that can be deformed following the deformation of the covering layer 20.

  The thickness of the skin layer 30 is preferably 0.1 mm or more and 1.5 mm or less, and more preferably 0.2 mm or more and 1.0 mm or less. By setting the thickness of the skin layer 30 to 0.1 mm or more, the skin layer 30 becomes difficult to tear, and the heat retention performance becomes high. Moreover, expansion-contraction performance becomes high by the thickness of a skin layer being 1.5 mm or less.

  An air reservoir 32 is formed in a portion surrounded by the skin layer 30, the inner side wall 24A of the valley portion 24 in the covering layer 20, and the side wall 24B. The air reservoir 32 is an annular closed space. By forming the air reservoir 32, an air layer of any of the mountain space 23 and the air reservoir 32 is disposed on the radially outer side of the porous resin layer 14.

(Porous resin layer)
The porous resin layer 14 is an example of the intermediate layer in the present invention, 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 rate 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 the case of a composite pipe, when connecting a joint or the like to the end of the inner pipe, it is required to shorten and shift the end of the covering layer to expose the end of the pipe. 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, and the end of the coating layer is shortened and deformed to expose the end of the tube. At the same time, the porous resin layer follows the operation of the coating layer well, and the leaving of 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 thickness of the porous resin layer 14 is in the natural state (in which no force such as compression or tension acts, temperature 23 ° C., relative humidity 45%), and the radial direction of the outer periphery of the tubular body 12 and the inner side wall 24A. It is preferable that the difference is greater than the difference with the inner surface, and that the difference is 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.

  In addition, although the porous resin layer 14 in the composite tube 10 shown in FIGS. 1-3 is a single | mono layer, it is not restricted to this, 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 low friction resin layer 13, the first porous resin layer 141, the second porous resin layer 142, and the covering layer 20 are laminated in this order. It is done. When the porous resin layer 14 is a multilayer, the heat protection property is improved as compared to the case where the porous resin layer 14 is a single layer.

  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.

(Action / effect)
In the composite pipe 10 according to the present embodiment, as shown in FIG. 3, the outside of the covering layer 20 is thermally insulated by the skin layer 30. An air reservoir 32 is formed in a portion surrounded by the skin layer 30, the inner side wall 24A of the valley portion 24 in the covering layer 20, and the side wall 24B. For this reason, the heat insulation of the coating layer 20 becomes high. Therefore, the heat retaining property of the composite pipe 10 is enhanced. Thereby, the tube 12 inserted into the inside of the composite tube 10 can be kept warm.

  Further, in the composite pipe 10, the porous resin layer 14 is provided between the pipe body 12 and the covering layer 20. For this reason, the heat retention effect of the tubular body is enhanced as compared with the case without the porous resin layer 14. Furthermore, a mountain space 23 is formed in a portion surrounded by the porous resin layer 14 and the outer side wall 22A of the mountain portion 22 in the covering layer 20 and the side wall 22B. Thus, the air space of either the mountain space 23 or the air reservoir 32 is disposed on the radially outer side of the porous resin layer 14. For this reason, the heat retention effect is enhanced.

  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.

  Moreover, it is preferable that the rigidity with respect to the force along the axial direction S of the skin layer 30 be smaller than the rigidity with respect to the force along the axial direction S of the outer side wall 22A. As a result, the skin layer 30 deforms more easily than the outer wall 22A, and as shown in FIG. 6, 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. Furthermore, the skin layer 30 is deformed. At this time, the air pushed out of the air reservoir 32 is pushed out between the skin layer 30 and the outer side wall 22A and held inside the skin layer 30. For this reason, it is suppressed that the air of the air pool 32 is discharged | emitted.

  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 and the skin layer 30 are deformed so as to expand, so that the valleys may be formed even if the bending angle and thickness of the covering layer 20 have some variations. It can suppress that 24 bulges radially outward, or the adjacent peak part 22 comrades do not approach, and will be in a distorted deformation state. 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. .

  In addition, although the skin layer 30 is arrange | positioned over substantially the whole in alignment with the axial direction of the coating layer 20 in this embodiment, embodiment of this invention is not limited to this. For example, it only needs to cover at least a part in the axial direction. In the case where the pipe body 12 is a hot water pipe connected to an outdoor water heater, or when the hot water pipe is inserted into the pipe body 12, for example, the skin layer is only a portion within a predetermined distance from the outdoors. By coating with 30, it is possible to keep warm efficiently.

  Further, the material forming the skin layer may not be an elastomer. For example, as with the porous resin layer 14, polyurethane, polystyrene, polyethylene, polypropylene, ethylene propylene diene rubber, a mixture of these resins, or the like may be used.

  In the case where the skin layer is formed of the same material as the porous resin layer 14, for example, as shown in FIG. 9, the resin is formed in a portion surrounded by the inner side wall 24A and the side wall 24B of the valley portion 24 in the covering layer 20. May be filled. In the skin layer 40 formed in this manner, the resin itself constituting the skin layer 40 does not necessarily have the air pool 32 (see FIG. 3) since the resin itself has a heat insulating performance.

  Furthermore, as a material for forming the skin layer, as with the covering layer 20, polyolefin such as polybutene, polyethylene, polypropylene, and crosslinked polyethylene, and vinyl chloride may be used. In this case, as in the skin layer 50 shown in FIG. 9 (B), the annular peak 52 that is convex outward in the radial direction and the annular valley 54 that is concave in the outer radial direction It is preferable to form a bellows-like shape which is alternately and continuously formed in the axial direction S. By forming in this manner, the skin layer 50 can be easily moved along the axial direction S.

  Moreover, although the composite pipe | tube 10 is equipped with the porous resin layer 14 and the pipe body 12 inside the coating layer 20 in this embodiment, the embodiment of this invention is not limited to this. For example, both or any of the porous resin layer 14 and the tubular body 12 may be omitted. That is, it is only necessary to provide the covering layer capable of inserting the tube and the skin layer 30. Even if the porous resin layer 14 is omitted, the heat retaining effect of the covering layer 20 by the skin layer 30 is maintained. If the tube 12 is omitted, any tube can be used.

(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, the embodiment of the present invention 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 a tubular body, a porous resin layer, and a bellows-like coating layer, when connecting a joint or the like to the end of the inner tubular body, the end of the coating layer is shortened and shifted. After exposing the part and connecting the end of the tube to a joint or the like, it is required to extend and restore the shortened covering layer and coat the tube again.

  On the other hand, 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 on the inner peripheral surface of the low friction resin layer 13 The value is smaller 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 tube to the tip of the force gauge (IMADA popular digital force gauge DS2), and shift the coating layer at the other end of the composite tube 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 .

10 composite tube, 12 tube, 14 porous resin layer (intermediate layer), 14S porous resin sheet, 20 coating layer, 20A resin layer (resin material), 22 peak,
24 valleys, 30 skin layers

Claims (4)

The tubular body has a tubular shape that can be inserted, and an annular peak that is convex radially outward and an annular valley that is concave radially outward are alternately formed in the axial direction to form a bellows. , A covering layer made of a resin material,
A skin layer which covers the outer periphery of the covering layer and thermally insulates the covering layer in at least a partial region in the axial direction of the covering layer, and which is stretchable along the axial direction of the covering layer;
Composite tube with.   The composite pipe according to claim 1, wherein an air pool is formed between the valley and the skin layer.   The composite tube according to claim 1, wherein the surface layer is bellows-shaped. A tube inserted into the covering layer;
An intermediate layer disposed between the tubular body and the covering layer and sandwiched between the valley portion and the tubular body and formed of a porous resin;
The composite pipe according to any one of claims 1 to 3, comprising: