JP4911771B2 - Synthetic resin pipe with joints at both ends - Google Patents

Description

  The present invention relates to an improvement in a flexible synthetic resin pipe having cylindrical joints at both ends.

  Conventionally, for example, in buildings such as middle- and high-rise apartments, connecting pipes that connect drain outlets such as bathtubs and toilets of each door to a common drain pipe arranged vertically along the building, or rigid synthetic resin As a connecting pipe for connecting the opposite ends of the straight tubular body, as described in Patent Document 1, both ends are provided on the outer peripheral surface of a flexible pipe made of a soft vinyl chloride resin. Reinforced spiral ridges made of hard polyvinyl chloride resin having a constant width and thickness except for the part are wound, and cylindrical joint parts made of hard vinyl chloride resin are provided at both ends of the tube main body. Things are known.

According to the connecting pipe configured as described above, the inner peripheral surface of the pipe main body is formed in a smooth surface, so that not only smooth drainage is possible, but also the outer peripheral surface of the pipe main body has a reinforcing spiral. Since the ridges are wound, the tube main body exposed between adjacent reinforcing spiral ridges can be maintained with a superior cross-sectional shape without the risk of crushing into a flat shape with excellent pressure resistance. Even if the opposite open ends of the pipes that should be connected by exhibiting good bendability due to the pipe wall part are misaligned from each other in the center, up and down, left and right, the joints on both ends of this pipe main body are opposed to these pipes. This has the advantage that it can be accurately connected to the open end.
JP 2003-214563 A

  However, according to the connecting pipe, since the pipe main body is made of a soft vinyl chloride resin, the weather resistance is inferior, and the plasticizer contained in the pipe may move to cause a harmful effect. There is a strong demand for connecting pipes made mainly of olefinic resins such as soft polyethylene and polypropylene that do not contain plasticizers. However, olefinic resins have poor adhesion and are therefore flexible by olefinic resins. When the pipe main body having the above is formed, the reinforcing spiral ridges and cylindrical joint portions made of hard vinyl chloride resin cannot be fused to the outer peripheral surface thereof. Must be formed of the same olefin resin that can be bonded to the tube main body.

  When the joints at both ends are formed of olefin resin in this way, a joint short pipe for connecting to a drain outlet or a straight pipe made of hard vinyl chloride resin is fitted on the outer peripheral surface of the joint and bonded together. Therefore, there is a problem that it cannot be used as a connecting pipe.

  The present invention has been made in view of such problems. The object of the present invention is that, although the flexible pipe main body is made of an olefin resin, the outer peripheral surface thereof is made of hard vinyl chloride resin. It is to provide a synthetic resin pipe having a structure in which a reinforcing spiral protrusion and a cylindrical joint portion are firmly and integrally fixed.

In order to achieve the above object, the synthetic resin pipe having joints at both ends according to the present invention has a flexible outer periphery of a soft synthetic resin pipe having a predetermined length as described in claim 1. Synthetic resin reinforcing spiral ridges having a certain width and thickness are wound around the surface, and a synthetic resin cylindrical joint is provided on the outer peripheral surface of both ends of the soft synthetic resin pipe main body. In the synthetic resin pipe, the soft synthetic resin pipe main body is made of olefin resin, while the reinforcing spiral protrusion is an olefin type whose inner surface is integrally fused to the outer peripheral surface of the soft synthetic resin pipe main body. forming an uneven engaging portion engaged with each other on the bonding surface by joining together the ridge portion made of hard vinyl chloride resin having a constant width of the outer surface on the inner layer material is formed into a flat surface made of a resin and it will be inseparably coupled to form further, cylindrical The hand part is an end of the pipe main body made of the olefin resin on the inner surface of the inner layer material in the reinforcing spiral ridge formed by integrally joining the ridge part made of hard vinyl chloride resin on the inner layer material made of olefin resin. It is formed into a cylindrical shape by fusing it integrally to the outer peripheral surface of the part and spirally winding it while joining the opposite side surfaces of the spiral ridge part to be wound next to the side surface of the spiral ridge part wound first. Has a structured.

Furthermore, in the synthetic resin pipe configured as described above, the present invention is such that the ridge portion made of the hard vinyl chloride resin and the inner layer material made of the olefin resin in the reinforced spiral ridge are engaged with each other on the joint surface. A concave / convex engaging portion is formed and combined so as not to be separated.

In the invention according to claim 2, the inner layer material made of the olefin-based resin is formed into a cross-sectional shape in which both side walls are provided on both side ends of the bottom surface having a certain width, while the ridge portion made of the hard synthetic resin is formed. The inner surface of the top wall having the same width as the inner layer material has a cross-sectional shape having protrusions embedded in the both side wall portions of the inner layer material, and the both side surfaces of the protrusions joined to each other and the both side wall surfaces of the inner layer material A concave-convex locking portion is formed on the joint surface.

According to the invention of claim 1, since the flexible pipe main body is made of an olefin resin, the pipe main body made of the olefin resin can be used for a long time without causing any harmful effects caused by the plasticizer. Reinforcing spiral ridges spirally wound on the outer peripheral surface of the hard vinyl chloride resin having a certain width on the inner layer material made of an olefin resin in which the inner surface is integrally fused to the outer peripheral surface of the tube main body Since the ridges made of a rigid vinyl chloride resin and the inner layer material made of an olefin-based resin are not bonded, the ridges are made to be bonded together. It can be surely wound spirally on the tube main body made of olefin resin via the inner layer material, and the crush strength of the tube main body can be imparted by this hard vinyl chloride resin protrusion. With When allowed to songs it can be bent while retaining the circular section shape without deforming the flat.

Furthermore, the cylindrical joint portion provided on the outer peripheral surface of both ends of the pipe main body made of olefin resin is a fixed surface in which the outer surface of the top wall portion is formed on a flat surface on the inner layer material made of olefin resin. The inner surface of the inner layer material of the reinforcing spiral ridge formed by integrally joining the ridge portion made of rigid polyvinyl chloride resin having a width is integrally fused to the outer peripheral surface of the end portion of the tube main body made of the olefin resin, In addition, the reinforcing spiral is formed into a cylindrical shape by spirally winding the side surface of the spiral ridge portion wound next to the opposite side surface of the spiral ridge portion to be wound next. Like the ridge, protrusion portion made of hard vinyl chloride resins even though it is not possible to adhere to the tube main body made of an olefin resin, and fused integrally with the outer peripheral surface of the pipe main body made of an olefin resin The me It is possible to form a joint portion made by firmly fixed to both outer peripheral surface of the pipe main body through a fin-based resin inner layer member the protruding portion made of the hard vinyl chloride resin, the tube entity than an olefin resin In spite of this, connection to other connection ports and pipes can be reliably performed by the cylindrical body portion formed by the top wall portion of the protruding portion made of the hard vinyl chloride resin.

Moreover, according to the present invention, the ridge portion made of the hard vinyl chloride resin and the inner layer material made of the olefin resin in the reinforced spiral ridge form an uneven engagement portion that is engaged with each other on the joint surface. Since they are connected inseparablely, when manufacturing the pipe, the inner layer material made of olefin resin is engaged with the ridge part made of hard vinyl chloride resin so that the outer peripheral surface of the pipe main body can be easily and accurately. The inner layer material can be integrally fused to the tube main body made of the same material in a state where the ridge portion made of the hard vinyl chloride resin can be spirally wound on the inner layer material made of the olefin resin. it can.

  Furthermore, since the protrusion made of hard vinyl chloride resin and the inner layer material made of olefin resin are bonded to each other by the concave-convex locking portion, they can be firmly integrated even though they are not bonded. Even if a pressing force to dent the tube main body acts on the outer peripheral surface of the tube main body, the concave and convex engaging portion prevents the inner layer material from detaching from the inside of the ridge portion in the dent direction of the tube main body. It is possible to keep the tube main body in a circular cross section.

Next, a specific embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a side view of a synthetic resin pipe A having joints at both ends, and FIG. 2 is a partial vertical side view thereof. The synthetic resin pipe A has an outer peripheral surface except for its both ends on the outer peripheral surface of a flexible soft synthetic resin pipe main body 1 having an inner peripheral surface formed on a smooth surface having the same diameter over the entire length. A synthetic resin reinforcing spiral ridge 2 having a constant width and a constant thickness is wound on a flat surface, and a cylindrical joint portion 3 made of synthetic resin is provided on the outer peripheral surfaces of both ends. 3 is integrally provided, and further, both ends of the reinforcing spiral protrusion 2 are integrally connected to the opposing surfaces of the cylindrical joint portions 3 and 3 respectively.

  In this synthetic resin pipe A, the soft synthetic resin pipe main body 1 is made of an olefin resin such as polyethylene or polypropylene, while the reinforcing spiral ridge 2 has a certain width that forms the outer surface as a flat surface. Convex and concave portions integrally joined to the inner surface of the protruding portion 2a made of hard vinyl chloride resin with a rod-like or strip-like inner layer material 2b made of the same resin as the tube main body 1 and made of olefin resin. Locking portions 4 and 5 are formed so as to be inseparably coupled, and the smooth inner surface of the inner layer material 2b facing the outer peripheral surface of the tube main body 1 is formed on the outer peripheral surface of the tube main body 1 made of an olefin resin. The reinforcing spiral ridges 2 are spirally wound at a constant pitch while being fused together.

The ridge 2a made of hard vinyl chloride resin that forms the reinforcing spiral ridge 2 and the inner layer material 2b made of olefin resin are not bonded, but the outer periphery of the pipe main body 1 in which the inner layer material 2b is made of the same olefin resin. The inner surface 2b is spirally wound while the inner surface is integrally fused to the surface, and the protrusions 2a made of hard vinyl chloride resin are provided on the joint surface of the inner layer material 2b. The protrusions 2a made of hard vinyl chloride resin are held by the inner layer material 2b in a state of being joined to the inner layer material 2b made of olefin resin, and are separated from the inner layer material 2b. There is no fear, and it can be provided integrally with the inner layer material 2b.

The cross-sectional shape of the reinforcing spiral ridge 2 is a rectangular shape in which the ridge portion 2a made of hard vinyl chloride resin is integrally joined by the concave and convex engaging portions 4 and 5 on the inner layer material 2b made of olefin resin as described above. What is necessary is just to form in a cross section, and there exist a thing of various structures as shown in FIGS. 3-8 as such a cross-sectional shape, for example.

  That is, in FIG. 3, the protruding portion 2a made of the hard vinyl chloride resin has a constant height and a constant height toward the outer peripheral surface of the pipe main body 1 at both ends in the width direction of the top wall portion 2a1 having a constant width and thickness. Both side wall portions 2a2 and 2a2 having a thickness are integrally formed so that the inner surface side is open, and the inner side surface is formed in an inward U shape or a gate shape, and the end portions of both side wall portions 2a2 and 2a2 are directed inward. Are formed in a spiral groove portion 2a3 formed by a space portion surrounded by the top wall portion 2a1 and both side wall portions 2a2 and 2a2. An inner layer material 2b made of the olefin resin having the same cross-sectional shape as that of the groove-shaped portion 2a3 is embedded, and concave engagement portions 5 are provided by engaging the convex engagement portions 4 on both side surfaces of the inner layer material 2b. It has the structure which becomes.

  FIG. 4 shows a spiral groove-like portion 2a3 ′ surrounded by a top wall portion 2a1 and both side wall portions 2a2 and 2a2 having a constant width and thickness in a ridge portion 2a made of hard polyvinyl chloride resin, in a dovetail shape. The opposite inner wall portions 2a2 and 2a2 of the lever are convex locking portions 4, and an inner layer material 2b formed in the same cross-sectional shape as the dovetail groove portion 2a3 ′ is placed in the groove portion 2a3 ′. It is made into the structure which was embed | buried and formed the concave latching | locking part 5 latched by the said convex latching | locking part 4 by the both-side wall surface which this inner layer material 2b inclined.

  FIG. 5 shows a projecting relationship on the opposite inner side surfaces of both side wall portions 2a2 and 2a2 in a ridge portion 2a made of hard vinyl chloride resin comprising a top wall portion 2a1 and a side wall portions 2a2 and 2a2 having a constant width and thickness. While forming the stop parts 4 and 4, on both side surfaces of the inner layer material 2b made of the olefin resin in the protrusion part 2a, the groove engagement parts 5 and 5 engaged with the convex engagement parts 4 and 4 are provided. It has a formed structure. FIG. 6 shows a plurality of concavo-convex locking portions locked to each other at several points on the inner side surfaces of both side walls 2a2 and 2a2 of the protruding portion 2a and at several points on both side surfaces of the inner layer material 2b joined to the inner side surface. 4 and 5 are formed.

  FIG. 7 shows that the spiral groove portion 2a3 in the ridge portion 2a made of hard polyvinyl chloride resin is formed in an elliptical shape, and the inner surfaces on both sides of the elliptical shape are formed in the concave locking portions 5 and 5, while In this structure, both end portions of the elliptical inner layer material 2b embedded in the groove-like portion 2a3 are formed in the convex locking portions 4 and 4.

  The ridge portion 2a made of the hard vinyl chloride resin shown in FIGS. 3 to 7 is formed in a U-shaped cross section or a gate shape. However, as shown in FIG. 8, the inner layer material 2b made of an olefin resin is used. Is formed in a cross-sectional shape having both side walls 2b2 and 2b2 at both ends of the bottom surface 2b1 having a constant thickness and width, while the protrusion 2a made of hard polyvinyl chloride resin has the same width as the inner layer material 2b. The inner wall 2a1 ′ has a cross-sectional shape in which the above-mentioned two side walls 2b2 and 2b4 embedded in 2b2 are provided on the inner surface of the inner layer material 2b. A structure in which the concave and convex engaging portions 4 and 5 are formed on the joint surface with the portions 2b2 and 2b2 may be employed.

  In the reinforcing spiral ridge 2 formed by integrally joining the inner layer material 2b made of olefin resin to the inner surface of the ridge portion 2a made of the hard vinyl chloride resin, the reinforcing spiral wound around the pipe main body 1 in a spiral shape. When the pitch of the ridges 2 is narrow and the tube main body 1 can be sufficiently protected by the reinforcing spiral ridges 2, as shown in FIGS. 9 and 10, the ridges made of hard polyvinyl chloride resin are used. The portion 2a and the inner layer material 2b made of olefin resin may be simply joined without using the concave and convex engaging portions 4 and 5.

  On the other hand, as shown in FIG. 2, the cylindrical joint portion 3 provided integrally on the outer peripheral surface of both ends of the pipe main body 1 made of olefin resin is a cylindrical body portion 3a made of hard vinyl chloride resin, and this cylindrical body. The inner layer material 3b made of an olefin resin embedded in the inner layer portion of the portion 3a. The inner layer material 3b is also directed toward the outer peripheral surface side of the pipe main body 1 in the same manner as the inner layer material 2b of the reinforcing spiral protrusion 2. The inner surface is exposed to be flush with the inner surface of the cylindrical portion 3b, and the inner surface is integrally fused to the outer peripheral surface of the tube main body 1 made of the same resin as the inner layer material 3b. .

  As a specific structure of the cylindrical joint portion 3, a wide reinforcing spiral protrusion 2 ′ having a width 2 to 4 times that of the reinforcing spiral protrusion 2 and having the same thickness is used. On the outer peripheral surface of the end portion, there is a structure in which the opposite side surface of the spiral ridge portion to be wound next is joined to the side surface of the spiral ridge portion that has been wound first and is spirally wound while being integrally fused. is doing. That is, the wide reinforced spiral ridge 2 ′, like the reinforced spiral ridge 2, is a ridge portion 2a ′ made of hard vinyl chloride resin and an olefin resin integrally bonded to the inner surface side of the ridge portion 2a ′. The inner layer material 2b 'made of olefin resin, and the inner surface of the inner layer material 2b' made of olefin resin is integrally fused to the outer peripheral surface of the end portion of the tube main body 1 made of the same resin, and the ridge made of hard polyvinyl chloride resin It is formed by spirally winding the part 2a ′ while joining the opposite side surfaces of the spiral ridge portion to be wound next to the side surface of the spiral ridge portion that has been previously wound as described above. ing.

  Accordingly, the cylindrical body portion of the cylindrical joint portion 3 made of hard vinyl chloride resin is formed by the top wall portion 2a1 'of the ridge portion 2a' of the wide reinforcing spiral ridge 2 'which is spirally wound in a state of being joined and fused together. 3a is formed, and the outer surface of the top wall 2a1 'is formed as a flat surface as shown in the figure, so that the outer peripheral surface of the cylindrical joint 3 is formed on a smooth surface having the same diameter over the entire length. can do. Although the protrusion 2a 'and the inner layer material 2b' are not shown in the drawing, as in the structure shown in FIGS. Yes.

  Since the synthetic resin pipe A having the joint parts 3 and 3 at both ends configured in this way, the flexible pipe main body 1 is formed of an olefin-based resin, so that there is no adverse effect caused by the plasticizer. Of course, although the tube main body 1 is made of an olefin resin, the rigid vinyl chloride resin protrusion 2a of the reinforcing spiral protrusion 2 is fused to the outer peripheral surface of the tube main body 1. It can be held by the inner layer material 2b made of the attached olefin resin, and the hard vinyl chloride resin protrusion 2a can provide pressure resistance and shape retention of the tube A.

  Further, on the outer peripheral surfaces of both ends of the pipe main body 1, the tube body 3 a constituting the outer layer part of the cylindrical joint parts 3, 3 is formed in the pipe main body although the pipe main body 1 is made of olefin resin. 1 can be made of a hard vinyl chloride resin through an inner layer material 3b made of an olefin-based resin fused together with a cylindrical body made of a hard vinyl chloride resin of these cylindrical joint portions 3, 3. As shown in FIG. 11, the pipe 3 to be connected can be bonded to the part 3a with the inner peripheral surface of one half of the short pipes 6 and 6 for joint made of hard vinyl chloride resin or the like fitted thereon, as shown in FIG. The pipe main body 1 is bent so that the joint short pipes 6, 6 can be connected to the opening ends opposed to P, and the joint short pipes 6, 6 are opened to the pipe ends P, P. The pipes P and P are connected to each other through the synthetic resin pipe A. Rukoto can.

  Next, the manufacturing method of the synthetic resin pipe A configured as described above will be briefly described with reference to FIGS. 12 and 13. First, a strip-like material made of a semi-molten olefin resin having a constant width and a constant thickness. 11 is extruded from the first molding nozzle 21 and is fused together by overlapping the opposite side portion of the following strip-shaped material portion on one side portion of the preceding strip-shaped material portion on the molding rotating shaft 20 as is well known. However, by winding in a spiral manner at a constant pitch, the tube main body 1 having the same inner diameter and a constant thickness over the entire length is formed, and the strip 11 made of the olefin resin is followed. An inner layer material 12b made of a semi-molten olefin resin is disposed in a groove-like portion 12a3 provided on the inner surface side of the protruding portion 12a made of a hard vinyl chloride resin in a semi-molten state from the second molding nozzle 22. The rotating shaft formed while extruding the protruding ridge 12 The inner layer material 12 made of the olefin resin is wound on the band material 11 made of the olefin resin spirally wound on the belt 11 made of the olefin resin with a constant pitch. By fusing and integrating with the outer peripheral surface, the reinforcing spiral ridge 2 is formed on the outer peripheral surface of the tube main body 1 as shown in FIG. In addition, although not shown in figure, the joining surface of the protrusion part 12a and the inner layer material 12b is mutually locked by the uneven | corrugated latching | locking parts 4 and 5.

Thus, when the pipe main body 1 having a predetermined length formed by spirally winding the reinforcing spiral ridge 2 on the outer peripheral surface is formed, the thickness of the ridge 12 is increased from the second forming nozzle 22 as shown in FIG. Spiral ridges that were previously wound around the outer peripheral surface of the pipe main body 1 by pushing out the nozzle so that only the width was expanded 2 to 4 times without changing the width. The groove-shaped portion of the projecting portion 12a 'made of hard polyvinyl chloride resin is integrally fused while joining the opposing side surfaces of the spiral projecting portion to be wound next to the side surface of the portion, and this widened projecting portion 12' be wrapped helically with the same pitch as the protrusions 12 while fused integrally with the outer peripheral surface of the pipe body 1 in which the inner surface of consisting of an olefin resin inner layer member 12b 'made of an olefin resin in 12a3 Due to this, the top wall of the ridge 12a 'made of hard polyvinyl chloride resin is continuously formed A joint comprising a cylindrical portion 3a ′ having a certain thickness and an inner layer material 12b ′ made of an olefin resin that is integrally provided on the inner layer portion of the cylindrical portion 3a ′ and is fused to the outer peripheral surface of the pipe main body 1. Form part 3 ′.

  When the joint portion 3 'is formed to be twice as long as the cylindrical joint portion 3 provided at both ends of the pipe main body 1 from which the joint body 3' is obtained, the ridge 12 subsequently pushed out from the second forming nozzle 22 is used. As described above, a constant pitch is applied to the outer peripheral surface of the pipe main body 1 formed by the strip 11 made of a semi-molten olefin resin extruded from the first molding nozzle 21 again. Thus, the reinforcing spiral ridge 2 is formed by spirally winding.

As described above, the tube main body 1 having a constant thickness is formed by spirally winding the strip-like material 11 made of a semi-molten olefin resin having a constant width and a constant thickness on the molding rotating shaft 20 while extruding it from the first molding nozzle 21. Forming a reinforcing spiral ridge 2 on a predetermined length portion of the tube main body 1 by spirally winding the ridge 12 pushed out from the second forming nozzle 22 on the tube main body 1 at a constant pitch. Then, following this process, the ridge pushed out from the second forming nozzle 22 is widened, and the widened ridge 12 'is joined to the pipe main body 1 with the side surfaces facing each other joined and fused together to a fixed length joint. The process of forming the part 3 ′ is repeated and sent to the front end side of the molding rotary shaft 20, cooled and hardened by a cooling device (not shown), and then disposed on the outer peripheral side of the molding rotary shaft 20 side. the length of the joint portion 3 'by to have rotary cutting blade Than to successively cut a central portion of the direction, a fixed-length synthetic resin tube having a joint portion 3, 3 at both ends of the hose main body 1 of a certain length which are wound helically the reinforcing spiral ridge 2 on the outer peripheral surface A is produced.

The side view of this invention synthetic resin pipe | tube. The vertical side view which abbreviate | omitted that part. The expanded vertical side view of a reinforcement spiral protrusion. The expanded vertical side view which has another cross-sectional shape of a reinforcement spiral protrusion. The expansion vertical side view which has another cross-sectional shape of a reinforcement spiral protrusion. The expansion vertical side view which shows the modification. The expanded vertical side view of the reinforcement spiral protrusion which forms the inner layer material in the ellipse shape. The expanded vertical side view of the reinforcement spiral protrusion couple | bonded by the several uneven | corrugated latching | locking part. The expanded vertical side view of the reinforcement spiral protrusion which does not provide the uneven | corrugated latching | locking part. The expansion vertical side view which shows the modification. The side view which carried out the cross section of a part which shows an example of a use condition. The side view which carried out the cross section of a part during forming the reinforcement spiral protrusion on the outer peripheral surface of a pipe | tube main body. The side view which carried out the cross section of a part in forming the joint part in the outer peripheral surface of a pipe | tube main body.

A Synthetic resin pipe 1 Pipe body made of olefin resin 2 Reinforced spiral ridge
2a Ridge made of hard polyvinyl chloride resin
2b Inner layer material made of olefin resin 3 Cylindrical joint
3a Cylindrical body made of hard vinyl chloride resin

Claims (2)

A synthetic resin reinforcing spiral ridge having a constant width and thickness is wound around the outer peripheral surface of a flexible synthetic resin pipe main body having a predetermined length, excluding both ends, and is made of the soft synthetic resin. In the synthetic resin pipe having the synthetic resin cylindrical joints provided on the outer peripheral surfaces of both ends of the pipe main body, the soft synthetic resin pipe main body is made of olefin resin, while the reinforcing spiral protrusion is made of this soft synthetic resin. A ridge made of hard vinyl chloride resin having a certain width is formed integrally on the inner layer material made of olefin resin, the inner surface of which is integrally fused to the outer peripheral surface of the tube main body. The joints are formed on the joint surfaces so as to be engaged with each other so as to be non-separable, and the cylindrical joint is made of a hard vinyl chloride resin on an inner layer material made of an olefin resin. The top of the ridge is joined together The inner surface of the inner layer material of the reinforcing spiral ridge is integrally fused to the outer peripheral surface of the end portion of the pipe main body made of the olefin resin, and the spiral is then wound around the side surface of the previously wound spiral ridge portion. A synthetic resin pipe having joint portions at both ends, which is formed in a cylindrical shape by spirally winding the opposing side surfaces of the protruding portion. The inner layer material made of olefin resin is formed into a cross-sectional shape with both side walls provided on both side ends of the bottom surface portion having a constant width, while the ridge portion made of hard synthetic resin has the same width as the inner layer material. A cross-sectional shape is formed by providing protrusions embedded in the both side wall portions of the inner layer material on the inner surface of the inner layer material, and uneven locking portions are formed on the joint surfaces between both side surfaces of the protrusions and the inner wall surfaces of the inner layer material. The synthetic resin pipe having a joint portion on both side portions according to claim 1 .

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