JP2019215010A - Corrugate tube and composite tube - Google Patents

Abstract

To provide a corrugate tube that allows a fluorine resin layer to be provided on its surface without bonding, and a composite tube.SOLUTION: A corrugate tube 20 has: a tubular substrate layer 26 composed of resin material; and a tubular fluorine resin layer 28 provided on at least one of the outer peripheral side or inner peripheral side of the substrate layer 26. An annular crest part 22, which projects radially outwards, and an annular trough part 24, the radial outside of which is bowed, are alternately formed axially, into the shape of bellows. The composite tube 10 has: a corrugate tube 20 that is guided along the periphery of the tube body 12 and can be shortened axially; and the tubular tube body 12 that is composed of resin material and is provided on the inner peripheral side of the corrugate tube 20.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a corrugated pipe and a composite pipe.

  Fluororesins have many properties such as chemical resistance, weather resistance, durability, and mechanical properties, but are expensive. Therefore, when a fluororesin is used for industrial products such as piping, a method of forming a thin fluororesin layer on the surface is generally used.

  Examples of the method of forming the fluororesin layer on the surface of the pipe include a method of coating the fluororesin after forming the pipe, and a method of forming a multilayer pipe to which the fluororesin layer is bonded by coextrusion. For example, Patent Literature 1 discloses that a fluororesin having an adhesive functional group is combined with a specific resin material such as a polyamide (PA) resin and co-extruded and chemically bonded to form a tube or a hose containing the fluororesin. A technique for manufacturing a multilayer molded article is disclosed.

International Publication No. WO 2004/110756

  When coating with a fluororesin after forming the pipe, the coating of the fluororesin is easily peeled off, and if there is only one pinhole, the pinhole may be deteriorated from that point. Further, it is difficult to obtain the surface accuracy of the pipe, and the pipe cannot be recycled or incinerated. Further, in the case where the coating is hardly peeled off by baking, it is necessary to form the pipe using a material that can withstand the heat of baking, so that the degree of freedom in design is reduced.

  When molding a multi-layer pipe to which a fluororesin layer is adhered, fluororesin generally has a property that it is difficult to adhere to other materials, and therefore, a combination of a fluororesin having an adhesive functional group and a specific resin material is used. It is necessary to provide a layer. Since the resin material forming the adhesive layer and the resin material forming the base layer need to be bonded, the resin material that can be used as a pipe material is limited, which increases the cost and reduces the degree of freedom in design. In addition, if a plasticizer is contained in the resin material constituting the pipe, the adhesive durability of the fluororesin is reduced, so that it is difficult to achieve both the moldability and flexibility of the pipe and the adhesive durability of the fluororesin. .

  The present invention has been made in view of the above circumstances, and has as its object to provide a corrugated pipe and a composite pipe that can be provided on a surface without bonding a fluororesin layer.

  The corrugated pipe according to claim 1 includes a tubular base material layer made of a resin material, and a tubular fluororesin layer provided on at least one of an outer circumferential side and an inner circumferential side of the base material layer. In addition, an annular crest that is convex outward in the radial direction and an annular valley that is concave outward in the radial direction are alternately formed in the axial direction to form a bellows shape.

  According to the above configuration, the corrugated tube having the base material layer and the fluororesin layer has an annular ridge that is convex outward in the radial direction and an annular valley that is concave outward in the axial direction alternately in the axial direction. It is formed to have a bellows shape. For this reason, the base layer and the fluororesin layer can be physically held by engaging the peaks and the valleys between the peaks and the valleys, and the outer peripheral surface of the corrugated pipe can be formed without bonding the fluororesin layer to the base layer. Alternatively, it can be provided on at least one of the inner peripheral surfaces.

  The composite pipe according to claim 2 includes the corrugated pipe according to claim 1, and a tubular pipe formed of a resin material and provided on an inner peripheral side of the corrugated pipe. Can be shortened in the axial direction while being guided by the outer periphery of the tubular body.

  According to the above configuration, the composite pipe having the fluororesin layer can be formed by providing the pipe body on the inner peripheral side of the corrugated pipe having the fluororesin layer. In addition, since the corrugated pipe can be shortened in the axial direction while being guided by the outer periphery of the pipe, the end of the pipe can be exposed by shortening the corrugated pipe.

  The composite pipe according to claim 3 is the composite pipe according to claim 2, wherein a tubular intermediate layer made of a porous resin material is provided between the corrugated pipe and the pipe. ing.

  According to the above configuration, the intermediate layer made of the porous resin material is provided between the corrugated pipe and the pipe. For this reason, it can suppress that the outer peripheral surface of a pipe and the inner peripheral surface of a corrugated pipe adhere | attach, and it becomes difficult to carry out relative movement, and can shorten a corrugated pipe smoothly and can expose the edge part of a pipe.

  According to the present invention, the fluororesin layer can be provided on the surface of the corrugated pipe and the composite pipe without bonding.

It is a perspective view showing a compound pipe in a 1st embodiment. It is a longitudinal section showing the compound pipe in a 1st embodiment. It is a longitudinal section partial enlarged view of the compound pipe in a 1st embodiment. It is a perspective view showing the state where the end of the tube of the compound pipe in a 1st embodiment was exposed. It is a longitudinal section showing the state where the end of the tube of the compound pipe in a 1st embodiment was exposed. It is a figure showing a manufacturing process of a compound pipe in a 1st embodiment. It is sectional drawing which showed the state after the mold clamping of the corrugation metal mold in the manufacturing process of the composite pipe in 1st Embodiment. It is a perspective view showing a corrugated tube in a 2nd embodiment. It is a longitudinal section showing a corrugated tube in a 2nd embodiment.

  Hereinafter, an example of an embodiment of a corrugated pipe and a composite pipe according to the present invention will be described in detail with reference to the drawings. Components indicated by the same reference numerals in each drawing mean that they are the same components. Further, in the embodiments described below, duplicate descriptions and reference numerals may be omitted.

  In the present specification, the term “step” includes not only an independent step but also the term “step” as long as its purpose is achieved even if it cannot be clearly distinguished from other steps. include. In the present specification, the amount of each component in the composition is, when a plurality of substances corresponding to each component are present in the composition, unless otherwise specified, the total amount of the plurality of substances present in the composition. Means In the present specification, the “main component” refers to a component having the largest mass-based content in a mixture, unless otherwise specified.

<First Embodiment>
First, the composite pipe 10 according to the first embodiment of the present invention will be described. As shown in FIGS. 1 and 2, the composite pipe 10 of the first embodiment includes a pipe body 12, a low-friction resin layer 13, an intermediate layer 14, and a corrugated pipe 20.

(Tube)
The tube 12 has a cylindrical shape and is made of a resin material. Examples of the resin material constituting the tubular body 12 include polybutene, polyethylene, crosslinked polyethylene, polyolefins such as polypropylene, and vinyl chloride. Even if only one kind of resin material is used, two or more kinds of resin materials may be used in combination. You may. Among them, polybutene is preferably used, and preferably contains polybutene as a main component, and more preferably contains 85% by mass or more in the resin material constituting the tubular body 12, for example. It should be noted that the resin material constituting the tube 12 may contain other additives.

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

(Corrugated pipe)
The corrugated pipe 20 has a cylindrical shape slightly larger than the outer diameter of the pipe 12 and covers the outer circumference of the pipe 12, the low-friction resin layer 13, and the intermediate layer 14. The corrugated tube 20 is a multi-layer tube having a base layer 26 made of a resin material and a fluororesin layer 28 provided on the outer peripheral side of the base layer 26.

  Examples of the resin material constituting the base layer 26 include polybutene, polyethylene, polypropylene, and polyolefins such as cross-linked polyethylene, and vinyl chloride. The resin may be used alone or in combination of two or more. Good. Among them, low-density polyethylene is suitably used, and preferably contains low-density polyethylene as a main component. For example, it is more preferably contained in a resin material constituting the base material layer 26 in an amount of 80% by mass or more, more preferably 90% by mass or more. Is more preferable.

  Further, the MFR (Melt Flow Rate) of the resin constituting the base layer 26 is preferably 0.25 or more, more preferably 0.3 or more, and 0.35 or more and 1.2 or less. Is more preferable. By setting the MFR to 0.25 or more, the resin of the base material layer 26 can easily enter the porous structure of the intermediate layer 14, and the degree of adhesion between the intermediate layer 14 and the valley 24 of the corrugated pipe 20 described later can be increased. Can be. By setting the MFR to 1.2 or less, burrs are less likely to occur. The resin material forming the base material layer 26 may contain other additives.

  On the other hand, the fluororesin layer 28 is a layer containing a fluororesin as a main component, and is laminated on the outer peripheral side of the base layer 26 to cover the outer periphery of the base layer 26. Further, the entire thickness of the fluororesin layer 28 is smaller than the entire thickness of the base layer 26. That is, the thickness of the fluororesin layer 28 is smaller than the thickness of the base material layer 26 at both the peak portion 22 and the valley portion 24 of the corrugated pipe 20 described later.

  As shown in FIG. 2, the corrugated tube 20 (that is, the base material layer 26 and the fluororesin layer 28) is formed in a bellows shape, and has an annular crest 22 that protrudes radially outward, and a concave portion that radially outwards. Are formed alternately and continuously in the axial direction S of the tubular body 12. The peak 22 is disposed outside the valley 24 in the radial direction R.

  As shown in FIG. 3, when the outermost portion of the corrugated pipe 20 in the bellows shape in the radial direction is the outer wall 22A, and the innermost portion in the radial direction is the inner wall 24A, the intermediate portion between the outer wall 22A and the inner wall 24A in the radial direction. With the portion M as a boundary, the outer side in the radial direction is a peak 22 and the inner side in the radial direction is a valley 24.

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

  On the radially inner side of the peak portion 22 of the corrugated pipe 20, a concave mountain space 23 is formed radially inward. It is preferable that a convex portion 14B of the intermediate layer 14 described later is inserted into the mountain space 23.

  Although not particularly limited, it is preferable that the length L1 of the ridge portion 22 in the axial direction S is set to be longer than the length L2 of the valley portion 24 in the axial direction S. The length L1 is preferably at least 1.2 times the length L2 in order to secure the ease of deformation of the outer wall 22A during the later-described contraction deformation.

  The length L1 is preferably not more than five times the length L2. This is because the flexibility of the composite pipe 10 can be maintained by setting the length L1 to five times or less the length L2. Also, if the length L1 is too long, the area of contact with the ground becomes large when the composite pipe 10 is laid, which makes it difficult to construct.

  Here, the length L1 is the distance between the outside of the corrugated pipe 20 in the axial direction S on the surface viewed from the outside in the radial direction R of the corrugated pipe 20 (the radial direction R of the corrugated pipe 20). (The distance between the surface on the one side in the axial direction S and the surface on the other side in the axial direction S) of the portion that protrudes outward.

  In addition, the length L2 is the distance between the outer side in the axial direction S on the surface viewed from the inner side in the radial direction R of the corrugated pipe 20 (in the radial direction R of the corrugated pipe 20) at the portion intersecting with the intermediate portion M in the corrugated pipe 20 (Distance between the surface on the one side in the axial direction S and the surface on the other side in the axial direction S) of the inwardly convex portion.

  The thickness H1 of the outer wall 22A of the corrugated pipe 20 is smaller than the thickness H2 of the inner wall 24A. The thickness H1 is preferably 0.9 times or less of the thickness H2 in order to ensure the ease of deformation of the outer wall 22A during the later-described contraction deformation.

  The radius difference ΔR between the outer surface of the peak 22 and the outer surface of the valley 24 is preferably 800% or less of the average thickness of the corrugated pipe 20. If the radius difference ΔR is too large, the portion (outside wall 22A) of the ridge 22 along the axial direction S is unlikely to be deformed during the shortening deformation, and in addition, the valley 24 may bulge outward in the radial direction R. In addition, the adjacent ridges 22 are likely to be distorted and deformed without approaching each other.

  When the radius difference ΔR is equal to or less than 800% of the average of the thickness of the corrugated pipe 20, the length of the ridge 22 in the axial direction S is set longer than the length of the valley 24 in the axial direction S. The above-mentioned deformation state can be effectively suppressed. Further, it is more preferable that the radius difference ΔR between the outer surfaces of the peaks 22 and the valleys 24 is 600% or less of the average thickness of the corrugated pipe 20.

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

(Low friction resin layer)
The low-friction resin layer 13 is a layer made of a resin material and has a lower slip resistance value on the inner peripheral surface than the slip resistance value on the inner peripheral surface of the intermediate layer 14. Examples of the low friction resin layer 13 include a sheet-like resin sheet layer. Examples of the resin material forming the low friction resin layer 13 include polyester, nylon, and polyolefin (for example, polyethylene, polypropylene, polybutene, and the like). The resin material forming the low friction resin layer 13 may contain other additives.

  Examples of the form of the low-friction resin layer 13 include non-woven fabrics (eg, melt blown, spun bond, etc.), knitted fabrics (eg, Russell, Tricot, Miranese, etc.), and woven fabrics (eg, plain weave, twill weave, mosaic weave, gauze weave, entanglement) Woven, etc.) and films.

  Among these, the low-friction resin layer 13 is formed of a polyester nonwoven fabric (that is, a nonwoven fabric containing polyester as a main component), a polyester tricot (that is, a tricot knitted fabric containing polyester as a main component), and a nylon nonwoven fabric (that is, nylon as a main component). Non-woven fabric containing), nylon tricot (that is, knitted fabric containing nylon as a main component), polyethylene film (that is, film containing polyethylene as a main component) and the like are preferable, and polyester non-woven fabric and nylon tricot are more preferable.

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 25 g / ^{m 2} or less is more preferable.

  The slip 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 slip resistance value on the inner peripheral surface of the intermediate layer 14, and for example, 10 or more and 24 or less, It is preferably from 12 to 23. The slip resistance value on the inner peripheral surface of the low friction resin layer 13 is, for example, 0.36 times or more and 0.90 times or less of the slip resistance value on the inner peripheral surface of the intermediate layer 14, and 0.44 times or more. 0.85 times or less is preferable.

  Here, the “slip resistance value” is specifically measured as follows. When measuring the slip resistance value on the inner peripheral surface of the low friction resin layer, first, arrange the corrugated pipe on the outer peripheral side of the pipe body, and measure the intermediate layer and the slip resistance value between the pipe body and the corrugated pipe. The target low-friction resin layer is inserted so that the low-friction resin layer is in contact with the tube to form a composite pipe having a length of 200 mm. Then, one end of the composite pipe is connected to the tip of a force gauge (a popular digital force gauge DS2 made by Imada), and the force (unit: N) when the corrugated pipe at the other end of the composite pipe is shifted by 50 mm. Is measured.

  When measuring the slip resistance on the inner peripheral surface of the intermediate layer, a corrugated pipe is arranged on the outer peripheral side of the pipe, and the intermediate layer for which the slip resistance is measured is placed between the pipe and the corrugated pipe. The composite tube having a length of 200 mm is formed by inserting the intermediate layer into contact with the tube. Then, the slip resistance of the intermediate layer is measured in the same manner as the measurement of the slip resistance of the low friction resin layer.

  It is preferable that the inner peripheral surface of the low friction resin layer 13 covers the outer periphery of the tubular body 12 while entirely contacting the outer periphery of the tubular body 12. Here, “total contact” means that all parts do not need to be in close contact with each other, but that substantially the entire surface is in contact. Therefore, for example, when the low-friction resin layer 13 is formed by winding a sheet, the seam portion is partially separated, and the wrinkled portion is partially separated.

(Middle layer)
The intermediate layer 14 is a tubular layer made of a porous resin material. Examples of the resin material constituting the intermediate layer 14 include polyurethane, polystyrene, polyethylene, polypropylene, and ethylene propylene diene rubber, and a mixture of these resins. Of these, polyurethane is preferable. The intermediate layer 14 is preferably a layer containing polyurethane as a main component (that is, a porous urethane layer). For example, the constituents of the intermediate layer 14 preferably contain at least 80% by mass of polyurethane, more preferably at least 90% by mass. Note that the porous resin material forming the intermediate layer 14 may contain other additives.

  The abundance ratio of the holes in the mid layer 14 (for example, the foaming ratio in the case of a foam) can be measured by the method described in Appendix 1 of JIS K6400-1 (2012), and is 25 holes / 25 mm or more. And more preferably 45 pieces / 25 mm or less. Further, the intermediate layer 14 is preferably a foam.

The density of the intermediate layer is preferably from 12 kg / m ^{3 to} 22 kg / m ³ . In the composite pipe 10 of the present embodiment, when connecting a joint or the like to the end of the inner pipe 12, it is required that the corrugated pipe 20 be shortened and shifted to expose the end of the pipe 12.

Here, when the density of the intermediate layer 14 is 22 kg / m ³ or less, the intermediate layer 14 has appropriate flexibility, and when the corrugated pipe 20 is shortened and deformed to expose the end of the pipe body 12, In addition, the intermediate layer 14 satisfactorily follows the operation of the corrugated pipe 20, and the leaving of the pipe body 12 on the outer surface is suppressed. As a result, the end of the tube 12 can be easily exposed.

On the other hand, the intermediate layer 14 has an appropriate strength when the density is 12 kg / m ³ or more, and the occurrence of breakage and breakage of the intermediate layer 14 during processing such as production of the composite pipe 10 is suppressed. The density of the intermediate layer 14 is more preferably in the range of 14 kg / m ³ or more and 20 kg / m ³ or less, from the viewpoint of suppressing leaving on the outer surface of the tube body 12 and suppressing breakage and breakage during processing. m ³ or more 18 kg / ^{m 3} or less is more preferred.

  Here, the density of the intermediate layer 14 can be measured by a method specified in JIS-K7222 (2005). The measurement environment is an environment with a temperature of 23 ° C. and a relative humidity of 45%.

  The method for controlling the density of the intermediate layer 14 within the above range is not particularly limited. For example, the ratio of the holes present in the intermediate layer 14 (for example, the foaming ratio in the case of a foam) is adjusted. And a method of adjusting the molecular structure of the resin (that is, adjusting the molecular structure of the monomer as a raw material of the resin and the cross-linked structure thereof).

  As shown in FIG. 2, the intermediate layer 14 is disposed between the low friction resin layer 13 and the corrugated pipe 20, and is sandwiched between the inner wall 24 </ b> A of the valley 24 of the corrugated pipe 20 and the pipe 12. Have been. In addition, it is preferable that the compressed portion is further compressed by the inner wall 24A and the tube body 12 to form a compression sandwiched portion 14A at the sandwiched portion.

  The thickness of the intermediate layer 14 is a natural state (a state in which a force such as compression or tension is not applied, at a temperature of 23 ° C. and a relative humidity of 45%). And it is preferable that the thickness is larger than the above difference.

  In the compression sandwiching portion 14A, the intermediate layer 14 is thinner than the thickness in the natural state due to the compression. A convex portion 14B is formed between adjacent compression sandwiching portions 14A of the intermediate layer 14. The convex portion 14B has a larger diameter than the compression holding portion 14A, and projects into the mountain space 23. When the intermediate layer 14 is compressed by the inner wall 24A and the tubular body 12, the compression sandwiching portions 14A and the convex portions 14B are formed alternately and continuously in the axial direction S, and the outer peripheral surface of the intermediate layer 14 has a wavy shape. Has become.

  It is preferable that the thickness of the intermediate layer 14 in the natural state is larger than the thickness of the low friction resin layer 13. The intermediate layer 14 preferably has a role of thermal protection in the composite pipe 10, and the thicker the layer, the better the thermal protection. On the other hand, if the low friction resin layer 13 is too thick, the ability of the intermediate layer 14 and the low friction resin layer 13 to follow the corrugated pipe 20 is reduced. Therefore, by making the intermediate layer 14 relatively thick and the low-friction resin layer 13 relatively thin, both the thermal protection and the ability to follow the corrugated pipe 20 are improved.

  Further, from the viewpoint of thermal protection and followability to the corrugated pipe 20, the thickness of the intermediate layer 14 in the natural state is preferably 10 times or more and 200 times or less, more preferably 20 times or more the thickness of the low friction resin layer 13. 150 times or less is more preferable, and 25 times or more and 100 times or less are further preferable.

  The length of the intermediate layer 14 in the axial direction S in the natural state is preferably 90% or more and 100% or less of the length of the corrugated pipe 20 in the axial direction S. This is because when the intermediate layer 14 is held in the stretched state between the tubular body 12 and the corrugated pipe 20, the relative movement between the intermediate layer 14 and the corrugated pipe 20 tends to occur when the corrugated pipe 20 is shortened and deformed. This is because the outer peripheral end of the tube 12 cannot be exposed without the intermediate layer 14 being shortened. In order to suppress the relative movement between the intermediate layer 14 and the corrugated pipe 20, the length of the intermediate layer 14 in the axial direction S in the natural state should be 90% or more and 100% or less of the axial length of the corrugated pipe 20. Is preferred.

  Further, the inner peripheral surface of the intermediate layer 14 is preferably bonded to the outer peripheral surface of the low friction resin layer 13. The adhesion of the intermediate layer 14 and the low friction resin layer 13 to the corrugated tube 20 in the intermediate layer 14 and the low friction resin layer 13 is further improved.

  As a method of bonding the intermediate layer 14 and the low friction resin layer 13, a method of applying an adhesive between the two layers and bonding, and a method of bonding by a frame laminating method are mentioned. Is preferred. That is, it is preferable that the intermediate layer 14 and the low friction resin layer 13 are a frame laminate adhesive.

(Production method)
Next, an example of a method for manufacturing the composite pipe 10 of the present embodiment will be described. As a method of manufacturing the composite pipe 10, for example, after the porous resin sheet 14 </ b> S is wound around the outer circumference of the pipe body 12 to form the intermediate layer 14, the base material layer 26 and the fluororesin layer 28 are A method of forming the corrugated tube 20 by molding by extrusion.

  Specifically, for example, a manufacturing apparatus 30 shown in FIG. 6 can be used for manufacturing the composite pipe 10. The manufacturing apparatus 30 includes an extruder 32, a die 34, a corrugating mold 36, a cooling tank 38, and a take-up device 39. In the manufacturing process of the composite pipe 10, the right side in FIG. 6 is the upstream side, and the pipe body 12 is manufactured while moving from the right side to the left side (hereinafter, referred to as “production direction Y”). The die 34, the corrugating mold 36, the cooling tank 38, and the take-off device 39 are arranged in this order with respect to the manufacturing direction Y, and the extruder 32 is arranged above the die 34.

  A sheet member (not shown) in which the tubular body 12 and the porous resin sheet 14S constituting the intermediate layer 14 are wound in a roll shape is disposed upstream of the die 34. The tubular body 12 and the roll-shaped porous resin sheet 14S are continuously pulled out by being pulled in the manufacturing direction Y by the take-off device 39. Before the die 34, the porous resin sheet 14S is wound around the entire outer circumference of the continuously drawn tube body 12 in front of the die 34 so that the end faces 14SA and 14SB face each other.

  The porous resin sheet 14S is inserted into the die 34 before the die 34 in order to prevent a tensile force from acting. The end surface 14SA and the end surface 14SB of the porous resin sheet 14S are not in contact with each other at the time of being inserted into the die 34 and the corrugating mold 36, and are separated from each other in the circumferential direction of the tube 12.

  A resin material forming the base material layer 26 and a fluororesin material forming the fluororesin layer 28 are applied to the outer periphery of the porous resin sheet 14S wound around the outer periphery of the tube body 12, respectively. Specifically, the resin material forming the base material layer 26 and the fluororesin material forming the fluororesin layer 28 are heated and melted, and supplied to the die 34 from discharge ports (not shown). Extruded simultaneously in two layers. Thus, a resin material 20A having a two-layer structure is formed on the outer periphery of the porous resin sheet 14S.

  The method of forming the two-layer resin material 20A is not limited to the method of simultaneously applying the resin material and the fluororesin material as described above. For example, after applying the resin material constituting the base material layer 26 to the outer periphery of the porous resin sheet 14S, the fluororesin material constituting the fluororesin layer 28 to the outer periphery of the resin material constituting the base material layer 26 in another step. May be applied.

  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 corrugating step, that is, a corrugated pipe, is performed by a corrugating mold 36 disposed downstream of the die 34. A step of forming the base material layer 26 and the fluororesin layer 28 into a bellows shape is performed.

  The corrugating mold 36 is, for example, a pair of molds, each of which has a semicircular inner surface, and an annular cavity 36 </ b> A in a portion corresponding to the crest 22 of the corrugated pipe 20 on the inner periphery. An annular inner protrusion 36B is formed at a portion corresponding to the valley portion 24, and has a bellows shape. Each cavity 36A is provided with a suction hole 36C having one end communicating with the cavity 36A and penetrating the corrugating mold 36. In the cavity 36A, air is taken in from the outside of the corrugating mold 36 via the suction hole 36C.

  On the downstream side of the die 34, the corrugating mold 36 approaches the resin material 20A from the left and right directions to bring the inner surfaces of the pair of molds into contact with the resin material 20A. Then, the corrugating mold 36 forms the resin material 20A by covering the outer periphery of the tubular extruded body 21 while compressing the resin material 20A by the inner protrusion 36B, and forms 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 corrugating mold 36 is sucked through a suction hole 36C by a suction device (not shown) to be a negative pressure. As a result, the resin material 20A is deformed outward in the radial direction R and is formed by the cavity 36A, and a bellows shape in which the ridges 22 and the valleys 24 are alternately arranged along the axial direction S from the resin material 20A. Is formed.

  Here, the convex portion 14B of the porous resin sheet 14S penetrates deeply into the mountain space 23 (see the partially enlarged view shown in FIG. 6) when the resin material 20A deforms outward in the radial direction R in the cavity 36A, Locked in the mountain space 23. The compression holding portion 14A of the porous resin sheet 14S is adhered to the inner wall 24A of the valley portion 24 of the corrugated pipe 20, and is compressed and held between the inner wall 24A and the tube 12.

  In a state before the clamping of the corrugating mold 36 in the corrugating step, both end surfaces (the end surface 14SA and the end surface 14SB) of the porous resin sheet 14S are separated from each other in the circumferential direction of the tubular body 12. At this time, in order to return the porous resin sheet 14S to the band shape, a force separating from each other acts on the end face 14SA and the end face 14SB. As a result, the resin material 20A is clamped under tension from the porous resin sheet 14S.

  When the corrugating mold 36 is clamped, the position of the end surface 14SA and the end surface 14SB of the porous resin sheet 14S (the end surface 14L) is set in the circumferential direction of the tube 12 as shown in FIG. , Are arranged at positions different from the parting surface 36D of the corrugating mold 36. The “position different from the parting surface 36D” refers to a position that does not overlap with the space between the parting surfaces 36D of the pair of corrugating dies 36 in the circumferential direction of the tube 12.

  At this time, it is preferable that the abutting position (the abutting surface 14L) between the end surface 14SA and the end surface 14SB of the porous resin sheet 14S is located at a position farthest from the parting surface 36D. That is, it is preferable to dispose the abutting surface 14L at a position corresponding to the deepest part of the cavity 36A (the part where the tangent is parallel to the parting surface 36D in the cavity 36A formed in a semicircular shape 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 corrugated pipe 20 formed when the corrugating 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, etc., but the parting line in the present invention may or may not be visible. Refers to both.

  After the corrugating step is performed in the corrugating mold 36, the corrugated pipe 20 is cooled in the cooling tank 38. Thus, the composite pipe 10 is manufactured.

(Action / Effect)
According to the composite pipe 10 of the present embodiment, the corrugated pipe 20 is a multilayer pipe having the base material layer 26 and the fluororesin layer 28 provided on the outer peripheral side of the base material layer 26. For this reason, the chemical resistance and weather resistance of the outer peripheral surfaces of the corrugated pipe 20 and the composite pipe 10 can be enhanced by the fluororesin layer 28.

  In addition, the corrugated pipe 20 has a bellows shape in which annular ridges 22 protruding radially outward and annular valleys 24 concave radially outward are alternately formed in the axial direction. Therefore, the base layer 26 and the fluororesin layer 28 can be physically held by engaging the ridges 22 and the valleys 24 with each other, and bonding the fluororesin layer 28 to the base layer 26. Instead, it can be provided on the outer peripheral surface of the corrugated pipe 20.

  This eliminates the need for an adhesive or an adhesive functional group for bonding and bonding the base material layer 26 and the fluororesin layer 28, thereby reducing the restrictions on the resin material that can be used as the base material layer 26 and designing. The degree of freedom can be increased. In addition, since the base material layer 26 and the fluororesin layer 28 are not bonded, when the composite tube 10 is discarded, the base material layer 26 and the fluororesin layer 28 can be easily separated and recycled.

  Further, according to the composite pipe 10 of the present embodiment, the corrugated pipe 20 can be shortened in the axial direction while being guided by the outer periphery of the pipe 12. Therefore, for example, when connecting the composite pipe 10 and the joint, as shown in FIGS. 4 and 5, the corrugated pipe 20 can be shortened in the axial direction S to expose the end of the pipe 12.

  Furthermore, according to the composite pipe 10 of the present embodiment, the low friction resin layer 13 and the intermediate layer 14 are provided between the corrugated pipe 20 and the pipe 12. For this reason, it can suppress that the outer peripheral surface of the pipe body 12 and the inner peripheral surface of the corrugated pipe 20 adhere to each other, making it difficult to relatively move, and the corrugated pipe 20 is smoothly shortened to expose the end of the tubular body. Can be.

  Further, the compression sandwiching portion 14A of the intermediate layer 14 is in close contact with the corrugated pipe 20, and the convex portion 14B is engaged between the adjacent side walls 24B of the valley portion 24. Therefore, the intermediate layer 14 can easily follow the movement of the corrugated pipe 20, so that the intermediate layer 14 is not left behind on the outer periphery of the pipe 12, and can be easily shortened together with the corrugated pipe 20.

  Further, according to the present embodiment, the low friction resin layer 13 is provided between the tube 12 and the intermediate layer 14. Therefore, when the corrugated pipe 20 is returned to its original state after the end of the corrugated pipe 20 is shortened and deformed to expose the end of the pipe body 12, the intermediate layer 14 and the low-friction resin layer 13 form the corrugated pipe 20. The end portion of the exposed tubular body 12 can be satisfactorily covered by the low friction resin layer 13, the intermediate layer 14, and the corrugated pipe 20, following the operation of the extension in the axial direction.

  According to the present embodiment, the length L1 shown in FIG. 3 is longer than L2 and the thickness H1 is smaller than H2 on the outer wall 22A of the peak 22 and the inner wall 24A of the valley 24. The outer wall 22A is more easily deformed than the inner wall 24A. Thereby, as shown in FIG. 5, the outer bent portion 22C of the peak portion 22 and the inner bent portion 24C of the valley portion 24 are deformed so that the adjacent peak portions 22 approach each other, and the corrugated pipe 20 at one end is It becomes easier to move in the direction in which the tube 12 is exposed.

  As described above, when the corrugated pipe 20 is shortened, the outer wall 22A is deformed so as to swell, so that even if there is some variation in the bending angle and the thickness of the corrugated pipe 20, the valley portion 24 has a diameter. It is possible to suppress the bulging outward in the direction and the deformation of the adjacent ridges 22 that are distorted without approaching each other.

  In addition, according to the present embodiment, the parting line PL of the corrugated pipe 20 and the abutting position (abutting surface 14L) of the porous resin sheet 14S constituting the intermediate layer 14 are different in the circumferential direction of the tube 12. Is located in the position. Therefore, even if the resin material 20A covering the outer periphery of the porous resin sheet 14S is loosened due to the end surfaces 14SA and 14SB being abutted during the mold clamping, the cavity 36A of the corrugating mold 36 is formed. The slack is pressed and disappears.

  Further, since the end surfaces 14SA and 14SB of the porous resin sheet 14S are not disposed at positions corresponding to the parting surface 36D of the corrugating mold 36, slack is hardly formed, and slack between the parting surfaces occurs. hard. Thereby, burrs are not easily generated in the corrugated pipe 20.

  By arranging the abutting surface 14L of the porous resin sheet 14S at a position farthest from the parting surface 36D in the circumferential direction of the tube 12, the abutting surface 14L may be partially displaced. Even if there is, the part is suppressed from being arranged at the same position as the parting surface 36D. Thereby, the effect of suppressing the generation of burrs is enhanced.

Second Embodiment
Next, a corrugated pipe 40 according to a second embodiment of the present invention will be described. As shown in FIGS. 8 and 9, the corrugated pipe 40 of the second embodiment is formed in a tubular shape, and has a base material layer 42 and fluororesins provided on the outer and inner circumferential sides of the base material layer 42, respectively. A multi-layer tube having layers 44 and 46 is provided.

  Further, the corrugated pipe 40 (that is, the base material layer 42 and the fluororesin layers 44 and 46) has a bellows-like shape like the corrugated pipe 20 of the first embodiment, and has an annular mountain that is projected outward in the radial direction. The part 48 and the annular valley part 50 whose radial outside is concave are formed alternately and continuously in the axial direction S.

  The base layer 42 is made of a resin material. In addition, as the resin material forming the base material layer 42, the same material as the base material layer 26 of the corrugated tube 20 of the first embodiment can be used.

  The fluororesin layers 44 and 46 are layers containing a fluororesin as a main component. The fluororesin layer 44 is laminated on the outer peripheral side of the base layer 42 and covers the outer periphery of the base layer 42. Is laminated on the inner peripheral side of the base material layer 42 and covers the inner periphery of the base material layer 42. Further, the thickness of each of the fluororesin layers 44 and 46 at both the peaks 48 and the valleys 50 of the corrugated pipe 40 is smaller than the thickness of the base layer 26.

  The corrugated pipe 40 of the present embodiment can be manufactured by the same method as the corrugated pipe 20 of the first embodiment. Although not shown, specifically, a resin material forming the base material layer 42 and a fluororesin material forming the fluororesin layers 44 and 46 are each heated and melted and extruded to form a resin material having a three-layer structure. After that, the resin material is corrugated to form a bellows-like corrugated pipe 40.

  According to the corrugated tube 40 of the present embodiment, the fluororesin layers 44 and 46 are provided on both the outer peripheral side and the inner peripheral side of the base layer 42. For this reason, the chemical resistance and weather resistance of both the outer peripheral surface and the inner peripheral surface of the corrugated pipe 40 can be enhanced by the fluororesin layers 44 and 46. Further, since the fluororesin layer 46 is provided on the inner peripheral surface of the corrugated pipe 40, for example, when the composite body is manufactured by inserting a pipe body into the inner peripheral side of the corrugated pipe 40, the pipe to the corrugated pipe 40 is not used. Easy insertion of the body.

  Further, the corrugated pipe 40 has a bellows shape in which an annular ridge 48 projecting outward in the radial direction and an annular valley 50 recessing outward in the radial direction are alternately formed in the axial direction. For this reason, similarly to the corrugated pipe 20 of the first embodiment, the base layer 42 and the fluororesin layers 44 and 46 can be physically held by engaging the ridges 48 and the valleys 50 with each other. The fluororesin layers 44 and 46 can be provided on the outer peripheral surface and the inner peripheral surface of the corrugated tube 40 without adhering to the base layer 42.

  This eliminates the need for an adhesive or an adhesive functional group for bonding and bonding the base material layer 42 and the fluororesin layers 44 and 46, and can reduce restrictions on resin materials that can be used as the base material layer 42. In addition, the degree of design freedom can be increased. Further, since the base material layer 42 and the fluororesin layers 44, 46 are not bonded, when the corrugated pipe 40 is discarded, the base material layer 42 and the fluororesin layers 44, 46 can be easily separated, and recycling is possible. Become.

<Other embodiments>
It should be noted that the present invention is not limited to the above embodiment at all, and can be implemented with appropriate modifications within the scope of the object of the present invention.

  For example, in the first embodiment, the low friction resin layer 13 is provided between the tube 12 and the intermediate layer 14, but the tube 12 and the intermediate layer 14 are directly connected without providing the low friction resin layer 13. You may contact. In this case, when the end of the tube 12 is exposed by shortening the corrugated tube 20, the intermediate layer 14 and the corrugated tube 20 are separated by the frictional force between the outer periphery of the tube 12 and the inner periphery of the intermediate layer 14. , Can be easily held in the shortened position.

  Further, in the first embodiment, the axial direction S of the tube 12 may be the slit width direction, and a plurality of slits disposed at regular intervals may be formed in the intermediate layer 14. By forming a slit in the intermediate layer 14, the intermediate layer 14 is easily deformed in the slit portion along the axial direction of the tube 12, and the intermediate layer 14 can be smoothly shortened along the outer periphery of the tube 12. it can.

  In particular, by disposing the slit on the corrugated pipe 20 side of the intermediate layer 14 and by matching the arrangement interval of the valley 24 of the corrugated pipe 20 in the axial direction S, the valley 24 of the corrugated pipe 20 and the intermediate layer 14 are formed. The slit can be engaged. Thereby, when the corrugated pipe 20 is shortened, the intermediate layer 14 can be made to follow more, and the end of the pipe 12 can be more smoothly exposed.

  In the second embodiment, the fluororesin layers 44 and 46 are provided on the outer and inner peripheral sides of the base layer 42 of the corrugated tube 40, respectively. It may be provided on at least one of the outer peripheral side and the inner peripheral side.

  Furthermore, in the first embodiment, the thickness H1 of the outer wall 22A of the corrugated pipe 20 is smaller than the thickness H2 of the inner wall 24A, but the thickness H1 may be the same as the thickness H2. Further, although the outer wall 22A has a substantially linear shape along the axial direction S, the outer wall 22A may have an arc shape bulging radially outward, or the inner wall 24A may have an arc shape bulging radially inward. Good.

  Further, at the time of manufacturing the composite pipe 10, the end surface 14SA and the end surface 14SB of the porous resin sheet 14S constituting the intermediate layer 14 on the upstream side of the die 34 are heated, and the end surface 14SA and the end surface 14SB are heated. It may be fused in advance. The resin material forming the corrugated pipe 20 is applied to the outer periphery of the porous resin sheet 14S in a state where both end faces of the porous resin sheet 14S are fused, so that the corrugated pipe 20 is formed at the time of mold clamping. The resin material is less likely to loosen.

  In addition, in the first embodiment, the intermediate layer 14 is a single layer, but is not limited to this, and the intermediate layer 14 may be composed of a plurality of layers.

Reference Signs List 10 composite pipe 12 pipe 14 intermediate layer 20, 40 corrugated pipe 22, 48 peak 24, 50 valley 26, 42 base material layer 28, 44, 46 fluororesin layer

Claims (3)

A tubular base layer made of a resin material,
A tubular fluororesin layer provided on at least one of an outer peripheral side and an inner peripheral side of the base material layer,
Have
An annular ridge that is convex outward in the radial direction and an annular valley that is concave outward in the radial direction are formed alternately in the axial direction and are in a bellows shape.
Corrugated pipe. A corrugated pipe according to claim 1,
A tubular tube made of a resin material and provided on an inner peripheral side of the corrugated tube;
Have
The corrugated pipe can be shortened in the axial direction while being guided by the outer periphery of the pipe body,
Composite tube.   The composite pipe according to claim 2, wherein a tubular intermediate layer made of a porous resin material is provided between the corrugated pipe and the pipe.