Cylindrical substrate

Abstract

The present invention provides a cylindrical substrate for lining materials that, when a rehabilitated pipe is formed within an existing pipeline by impregnating the cylindrical substrate with a curable resin, then inserting and expanding / curing it, increases the initial rigidity of the rehabilitated pipe when external pressure is applied, thereby increasing the strength of the rehabilitated pipe. [Solution] A tubular base material for a lining material that reinforces existing pipelines by lining the inner surface of the existing pipeline, comprising n (n is any natural number of 3 or more) first to nth mats made of fiber and tubular in shape, which are stacked in order from the inside to the outside, and each of the first to nth mats has first overlapping portions to nth overlapping portions where both ends overlap, and at least the m-2nd overlapping portion (m is any natural number of 3 or more and n or less) partially overlaps the m-1st overlapping portion in the thickness direction of the tubular base material.

Description

[Technical Field]

[0001] The present invention relates to a cylindrical base material for a lining material that reinforces an existing pipeline by lining the inner surface of the existing pipeline. [Background Art]

[0002] As a lining material for reinforcing existing pipelines such as sewer pipes, there is one described in Patent Document 1, for example.

[0003] FIG. 1 of Patent Document 1 describes a liner having overlapping portions 8 to 12 formed by stacking intermediate layers 3 to 7 (corresponding to mats) that are evenly shifted from each other. Since the overlapping portions do not overlap each other in this liner (see FIG. 8 of the present application), as shown in FIG. 6 of Patent Document 1, all the intermediate layers 3 to 7 can be folded collectively, thereby simplifying the manufacturing process. [Prior Art Literature] [Patent Literature]

[0004] [Patent Document 1] International Publication WO2000050801A2 [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] However, in a liner as described in Patent Document 1, when a liner obtained by impregnating the intermediate layers 3 to 7 with a curable resin is inserted into an existing pipeline, expanded and cured to form a rehabilitated pipe in the existing pipeline, if external pressure is applied to the rehabilitated pipe, since the overlapping portions 8 to 12 are arranged apart from each other, each of the overlapping portions 8 to 12 may independently become an origin of damage. For this reason, it may become difficult to improve the initial stiffness and strength of the rehabilitated pipe.

[0006] Therefore, the present invention aims to provide a tubular substrate for lining material that, when a rehabilitated pipe is formed inside an existing pipeline by impregnating a tubular substrate with a curable resin and then inserting and expanding / curing it, increases the initial rigidity of the rehabilitated pipe when external pressure is applied to it, thereby increasing the strength of the rehabilitated pipe. [Means for solving the problem]

[0007] To solve the above problems, the present invention provides a cylindrical base material for a lining material that reinforces existing pipelines by lining the inner surface of the existing pipeline, A fibrous, tubular structure consisting of n (where n is any natural number greater than or equal to 3) mats, from the first to the nth, is stacked in order from the inside out. Each of the first to nth mats has a first to nth overlapping portion formed by overlapping ends, At least the m-2 overlap portion (where m is any natural number between 3 and n) is a cylindrical substrate that partially overlaps the m-1 overlap portion in the thickness direction of the cylindrical substrate.

[0008] According to the above configuration, when a tubular base material for lining material is impregnated with a curable resin, inserted into an existing pipeline, and expanded and cured to form a rehabilitated pipe within the existing pipeline, the initial rigidity when external pressure is applied to the rehabilitated pipe can be increased, thereby increasing the strength of the rehabilitated pipe. Note that n is a value corresponding to the number of layers of mats (1st mat to nth mat) that make up the tubular substrate. Furthermore, m is a value that defines which overlapping sections of the tubular substrate are overlapping among the first to nth overlapping sections.

[0009] Furthermore, in the above-mentioned tubular substrate, The k-2 overlap portion (where k is any natural number between 3 and n) may partially overlap the k-1 overlap portion in the thickness direction of the cylindrical substrate. k is a value that defines which overlapping sections of the tubular substrate are overlapping among the first to nth overlapping sections.

[0010] According to the above configuration, for example, if n is 6, then k will be 3, 4, 5, or 6. As a result, the first lap portion partially overlaps with the second lap portion located outside it, the second lap portion partially overlaps with the third lap portion located outside it, the third lap portion partially overlaps with the fourth lap portion located outside it, and the fourth lap portion partially overlaps with the fifth lap portion located outside it. In this way, the first lap portion to the k-2 lap portion each partially overlaps with the second lap portion to the k-1 lap portion located outside them. Therefore, when a rehabilitated pipe is formed inside an existing pipeline by impregnating a cylindrical substrate with a curable resin and then inserting and expanding it, even if external pressure is applied to the rehabilitated pipe, the ends of the first lap portion to the k-1 lap portion will not be pulled apart, thus further suppressing the first lap portion to the k-1 lap portion from becoming the starting point of damage. In other words, the initial rigidity when external pressure is applied to the rehabilitated pipe can be increased, thereby increasing the strength of the rehabilitated pipe.

[0011] Furthermore, in the above-mentioned tubular substrate, The first to the (n-1)th overlapping portions may be arranged in a stepped manner in a diagonal direction in the thickness direction of the cylindrical substrate.

[0012] According to the above configuration, the first to the (n-1)th overlapping sections can be overlapped in one direction with a unidirectional shift in the circumferential direction of the cylindrical substrate. This prevents the thickness of the cylindrical substrate from becoming excessively thick in localized areas. Furthermore, when a rehabilitated pipe is formed within an existing pipeline by impregnating a tubular substrate with a curable resin and then inserting it into the existing pipeline to expand and harden, the intermediate position between the first lap portion and the (n-1)th lap portion in the circumferential direction of the tubular substrate is positioned to correspond to the top of the existing pipeline. Therefore, even if pressure is applied from the top, the first lap portion is positioned further away from the intermediate position, thus preventing the first lap portion from becoming the starting point of damage.

[0013] Furthermore, in the above-mentioned tubular substrate, The first wrap portion may be positioned at the same location as the n wrap portion in the circumferential direction of the cylindrical substrate.

[0014] According to the above configuration, when the cylindrical substrate is inserted into an existing pipeline and the cylindrical substrate is expanded, the first and nth lap portions are compressed in the thickness direction compared to when they are not positioned at the same location in the circumferential direction. As a result, when the curable resin impregnated in the cylindrical substrate is cured to form a rehabilitated pipe inside the existing pipeline, even if external pressure is applied to the rehabilitated pipe, it becomes less likely that both ends of the first and nth lap portions will be pulled apart.

[0015] Furthermore, in the above-mentioned tubular substrate, The first to nth overlapping portions may each be superimposed with one end of each of the two ends positioned inside the other end.

[0016] With the above configuration, for example, one end of the second mat is sandwiched between the other end of the first mat and the other end of the second mat, which increases the circumferential frictional resistance. In other words, the resistance force in the direction that separates one end of the second mat from the other end of the second mat can be increased. As a result, when a rehabilitated pipe is formed inside an existing pipeline by impregnating a cylindrical substrate with a curable resin and then inserting and expanding it after curing, the initial rigidity of the rehabilitated pipe when external pressure is applied can be increased, thereby increasing the strength of the rehabilitated pipe. [Effects of the Invention]

[0017] This invention provides a tubular substrate for lining materials that, when a rehabilitated pipe is formed within an existing pipeline by impregnating a tubular substrate with a curable resin and then inserting and expanding / curing it, increases the initial rigidity of the rehabilitated pipe when external pressure is applied, thereby increasing the strength of the rehabilitated pipe. [Brief explanation of the drawing]

[0018] [Figure 1] This is a circumferential cross-sectional view of the cylindrical substrate according to this embodiment. [Figure 2] This is an enlarged view of A, the cylindrical substrate in Figure 1. [Figure 3]It is an explanatory diagram of a method for manufacturing a liner provided with a cylindrical base material according to the present embodiment. [Figure 4] It is an explanatory diagram of a method for manufacturing a liner provided with a cylindrical base material according to the present embodiment. [Figure 5] It is an explanatory diagram of a method for manufacturing a liner provided with a cylindrical base material according to the present embodiment. [Figure 6] It is an explanatory diagram of a lining step using a cylindrical base material according to the present embodiment. [Figure 7] It is a diagram showing the strength evaluation test results for rehabilitated pipes according to Example 1, Example 2 and Comparative Example 1. [Figure 8] It is an explanatory diagram of a conventional liner.

Mode for Carrying Out the Invention

[0019] (Embodiment) The cylindrical base material 3 according to the embodiment will be described. The existing pipeline to be reinforced is a pipeline that is mainly buried underground, such as a sewer pipe, a water supply pipe, and a gas pipe. The cylindrical base material 3 is an intermediate material for a rehabilitated pipe formed by curing an impregnated curable resin. That is, the inner surface of the existing pipeline will be lined with the rehabilitated pipe formed by curing the curable resin impregnated in the cylindrical base material 3.

[0020] (Liner 1) As shown in FIG. 1, the liner 1 includes a flattened cylindrical inner tube 2, and a cylindrical base material 3 in which fibrous cylindrical first mat 31 to sixth mat 36 are sequentially laminated from the inside to the outside on the outer circumference of the inner tube 2.

[0021] (Inner Tube 2) The inner tube 2 is disposed inside the cylindrical base material 3. For the material constituting the inner tube 2, for example, rubber, nylon, silicone or the like is selected according to the application. By expanding, the inner tube 2 pushes and spreads the cylindrical base material 3 from the inside to the outside, and plays a role of bringing the cylindrical base material 3 into close contact with the inner surface of the existing pipeline.

[0022] (Cylindrical base material 3) The first to sixth mats 36 that make up the tubular substrate 3 are long, rectangular, sheet-like glass fiber substrates. Figure 3 shows a portion of the length of the first to sixth mats 31 to 36. For the first to sixth mats 31 to 36 that constitute the tubular base material 3, for example, a roving cloth woven using glass fiber bundles may be used. Alternatively, a non-crimp fabric (NCF) can be used, in which glass fibers are arranged without twisting or weaving, laminated in multiple directions, and fixed with stitching thread. In this case, the waviness of the glass fibers is reduced, and the reduction in strength of the glass fibers when a load is applied can be minimized.

[0023] As shown in Figure 2, the first mat 31 has a first overlap portion 311 formed by overlapping with one end 311a in the width direction positioned inside the other end 311b. Similarly, the second mat 32 has a second overlap portion 321 formed by overlapping with one end 321a in the width direction positioned inside the other end 321b. Similarly, the third mat 33 has a third overlap portion 331 formed by overlapping with one end 331a in the width direction positioned inside the other end 331b. Similarly, the fourth mat 34 has a fourth overlap portion 341 formed by overlapping with one end 341a in the width direction positioned inside the other end 341b. Similarly, the fifth mat 35 has a fifth overlap portion 351 formed by overlapping with one end 351a in the width direction positioned inside the other end 351b. Similarly, the sixth mat 36 has a sixth overlap portion 361 formed by overlapping with one end portion 361a in the width direction positioned inside the other end portion 361b. As described above, the first to sixth overlapping sections 311 to 361 each overlap with one end 311a to 361a positioned inside the other end 311b to 361b.

[0024] With the above configuration, for example, one end 321a of the second mat 32 is sandwiched between the other end 311b of the first mat 31 and the other end 321b of the second mat 32, thereby increasing the circumferential frictional resistance of the cylindrical base material 3. That is, the resistance force in the direction that separates one end 321a of the second mat 32 from the other end 321b of the second mat 32 can be increased. As a result, when the cylindrical base material 3 is impregnated with a curable resin, inserted into an existing pipeline, expanded and cured to form a rehabilitated pipe within the existing pipeline, the initial rigidity when external pressure is applied to the rehabilitated pipe can be increased, thereby increasing the strength of the rehabilitated pipe.

[0025] Furthermore, as shown in Figure 2, a portion of the other side of the first lap portion 311 overlaps with a portion of one side of the second lap portion 321 in the thickness direction of the cylindrical substrate 3. Similarly, a portion of the other side of the second lap portion 321 overlaps with a portion of one side of the third lap portion 331 in the thickness direction of the cylindrical substrate 3. Similarly, a portion of the other side of the third lap portion 331 overlaps with a portion of one side of the fourth lap portion 341 in the thickness direction of the cylindrical substrate 3. Similarly, a portion of the other side of the fourth lap portion 341 overlaps with a portion of one side of the fifth lap portion 351 in the thickness direction of the cylindrical substrate 3.

[0026] According to the above configuration, the first to fourth lap sections 311 to 341 partially overlap the second to fifth lap sections 321 to 351, which are located outside of them. Therefore, when a rehabilitated pipe is formed inside an existing pipeline by impregnating the cylindrical base material 3 with a curable resin and then inserting it into the existing pipeline to expand and harden, even if external pressure is applied to the rehabilitated pipe, the ends of the first to fifth lap sections 311 to 351 will be pulled apart, thus preventing the first to fifth lap sections 311 to 351 from becoming the starting point of damage. In other words, the initial rigidity when external pressure is applied to the rehabilitated pipe can be increased, thereby increasing the strength of the rehabilitated pipe.

[0027] Furthermore, the first to fifth overlapping sections 311 to 351 are arranged in a stepped manner in a diagonal direction from one side to the other in the thickness direction of the cylindrical substrate 3, as shown in the circumferential cross-sectional view of the cylindrical substrate 3 in Figure 2.

[0028] According to the above configuration, the first to fifth overlapping portions 311 to 351 can be overlapped in one direction with a slight offset in the circumferential direction of the cylindrical substrate 3. This prevents the thickness of the cylindrical substrate 3 from becoming excessively thick in any particular area. Furthermore, when a rehabilitated pipe is formed within an existing pipeline by impregnating the cylindrical substrate 3 with a curable resin and then inserting it into the existing pipeline to expand and harden, if the intermediate position between the first lap portion 311 and the fifth lap portion in the circumferential direction of the cylindrical substrate 3 is positioned to correspond to the top of the existing pipeline, then even if pressure is applied from the top, the first lap portion 311 will be positioned further away from the intermediate position, thus suppressing the first lap portion 311 from becoming the starting point of damage.

[0029] Furthermore, as shown in Figure 2, the first wrap portion 311 and the sixth wrap portion 361 are positioned at the same location in the circumferential direction of the cylindrical base material 3.

[0030] According to the above configuration, when the cylindrical base material 3 is inserted into the existing pipeline and the cylindrical base material 3 is expanded, the first lap portion 311 and the sixth lap portion 361 are compressed in the thickness direction compared to when the first lap portion 311 and the sixth lap portion 361 are not positioned at the same location in the circumferential direction. As a result, when the curable resin impregnated in the cylindrical base material 3 is cured to form a rehabilitated pipe in the existing pipeline, even if external pressure is applied to the rehabilitated pipe, it becomes less likely that both ends of the first lap portion 311 and the sixth lap portion 361 will be pulled apart. In other words, it is possible to suppress the first lap portion 311 and the sixth lap portion 361 from becoming the starting point of damage.

[0031] (Method of manufacturing liner 1) Next, a method for manufacturing the liner 1, which includes an inner tube 2 and a cylindrical base material 3, will be described. First, lay down the sixth mat 36 as shown in Figure 3. Next, the fifth mat 35, fourth mat 34, third mat 33, second mat 32, and first mat 31 are stacked on top of the sixth mat 36, shifting them slightly as they go. In this case, one end 311a of the first mat 31 and one end 361a of the sixth mat 36 are positioned at approximately the same location in the width direction. Similarly, the other end 311b of the first mat 31 and the other end 361b of the sixth mat 36 are positioned at approximately the same location in the width direction. Next, the inner tube 2 is placed on the first mat 31.

[0032] Next, as shown in Figure 4, one end 311a of the first mat 31 is folded along the inner tube 2. Subsequently, the other end 311b of the first mat 31 is folded so that it overlaps with the one end 311a of the first mat 31. At this time, the first overlap portion 311 is formed when the one end 311a of the first mat 31 is positioned inside the other end 311b. Next, one end 321a of the second mat 32 is folded so that it overlaps with the other end 311b of the first mat 31. Then, the other end 321b of the second mat 32 is folded so that it overlaps with the one end 321a of the second mat 32. At this time, the second overlap portion 321 is formed when the two mats are overlapped with one end 321a of the second mat 32 positioned inside the other end 321b. Here, a portion of the other side of the first overlap portion 311 is arranged to overlap with a portion of one side of the second overlap portion 321 in the thickness direction of the cylindrical base material 3.

[0033] Next, one end 331a of the third mat 33 is folded so that it overlaps with the other end 321b of the second mat 32. Then, the other end 331b of the third mat 33 is folded so that it overlaps with the one end 331a of the third mat 33. At this time, the third overlap portion 331 is formed when the one end 331a of the third mat 33 is positioned inside the other end 331b. Here, a portion of the other side of the second overlap portion 321 is positioned to overlap with a portion of one side of the third overlap portion 331 in the thickness direction of the cylindrical base material 3.

[0034] Next, one end 341a of the fourth mat 34 is folded so that it overlaps with the other end 331b of the third mat 33. Then, the other end 341b of the fourth mat 34 is folded so that it overlaps with the one end 341a of the fourth mat 34. At this time, the fourth lap portion 341 is formed when the four mats are overlapped with one end 341a of the fourth mat 34 positioned inside the other end 341b. Here, a portion of the other side of the third overlap portion 331 is arranged to overlap with a portion of one side of the fourth overlap portion 341 in the thickness direction of the cylindrical base material 3.

[0035] Next, one end 351a of the fifth mat 35 is folded so that it overlaps with the other end 341b of the fourth mat 34. Then, the other end 351b of the fifth mat 35 is folded so that it overlaps with the one end 351a of the fifth mat 35. At this time, the fifth lap portion 351 is formed when the five mats are overlapped with one end 351a of the fifth mat 35 positioned inside the other end 351b. Here, a portion of the other side of the fourth overlap portion 341 is positioned to overlap with a portion of one side of the fifth overlap portion 351 in the thickness direction of the cylindrical base material 3.

[0036] Next, one end 361a of the sixth mat 36 is folded so that it overlaps with the fifth mat 35. Then, the other end 361b of the sixth mat 36 is folded so that it overlaps with the one end 361a of the sixth mat 36. At this time, the sixth lap portion 361 is formed when the six mats are overlapped with one end 361a of the sixth mat 36 positioned inside the other end 361b. Here, the sixth lap portion 361 is positioned at the same location in the width direction as the first lap portion 311.

[0037] Following the above procedure, as shown in Figure 5, cylindrical first mats 31 to 6th mats 36 are sequentially laminated on the outer circumference of the inner tube 2 from the inside to the outside, and the first lap portions 311 to 5th lap portions are arranged in a stepped manner in a diagonal direction from one side to the other in the thickness direction of the cylindrical base material 3, thereby manufacturing a cylindrical base material 3.

[0038] Subsequently, although not shown in the diagram, a film 4 (see Figure 6) is wrapped around the outer circumference of the cylindrical substrate 3, covering the cylindrical substrate 3 with the film 4, and the liner 1 is manufactured.

[0039] (Lining the inner surface of existing pipelines) Next, we will briefly explain the lining process using Liner 1 for the inner surface of existing pipelines, such as sewer pipes, that are to be reinforced.

[0040] First, the worker impregnates the cylindrical base material 3 of liner 1 with a liquid or paste-like curable resin before it hardens. Examples of curable resins used to impregnate the cylindrical substrate 3 include thermosetting resins such as epoxy resins, unsaturated polyester resins, and vinyl ester resins, as well as photocurable resins that harden when irradiated with ultraviolet light or the like.

[0041] Next, the worker pulls the liner 1, which is a cylindrical base material 3 impregnated with a curable resin, into the existing pipeline such as a sewer pipe that is to be reinforced.

[0042] Next, the worker introduces a fluid such as air from the inside of the inner tube 2 of the liner 1 to inflate (expand) the liner 1 and make it tightly adhere to the inner surface of the existing pipeline.

[0043] Next, the worker cures the curable resin impregnated into the cylindrical base material 3 of liner 1. For example, if the curable resin impregnated into the cylindrical substrate 3 is a thermosetting resin, hot water or steam is introduced into the inner tube 2, and the thermosetting resin impregnated into the cylindrical substrate 3 is cured while the liner 1 is in close contact with the inner surface of the existing pipeline. Furthermore, if the curable resin impregnated into the cylindrical substrate 3 is a photocurable resin, the liner 1 is placed in close contact with the inner surface of the existing conduit with an ultraviolet irradiation device inside the liner 1, and ultraviolet light is irradiated from the inside of the inner tube 2 using the ultraviolet irradiation device to cure the photocurable resin impregnated into the cylindrical substrate 3.

[0044] Next, the worker cures the curable resin impregnated into the cylindrical base material 3 of liner 1, and then peels the inner tube 2 of liner 1 from the cylindrical base material 3.

[0045] Through the above process, the rehabilitated pipe (see Figure 6), formed by the curable resin impregnated into the cylindrical substrate 3, lines the inner surface of the existing pipeline.

[0046] If a rehabilitated pipe is lined using the above process, its initial rigidity when external pressure is applied to the pipe can be increased, thereby increasing its strength.

[0047] (Other embodiments) (1) In the above embodiment, six mats, numbered from the first mat 31 to the sixth mat 36, are stacked in order from the inside to the outside in the cylindrical substrate 3. In this regard, in the case of a tubular substrate, the number of mats may be n (where n is any natural number greater than or equal to 3), in which case the first to nth mats are stacked in order from the inside to the outside. Note that n is a value corresponding to the number of layers of mats that make up the tubular substrate. For example, if n is 4, then in a cylindrical substrate, four mats, the first to the fourth mat, are stacked in order from the inside to the outside.

[0048] Furthermore, if there are n mats, the first to nth mats each have a first to nth overlapping section (n overlapping sections) where both ends overlap. For example, if n is 4, then the first to fourth mats each have a first overlapping section to a fourth overlapping section where both ends overlap.

[0049] Furthermore, at least the (m-2) overlapping section (where m is any natural number between 3 and n) must partially overlap the (m-1) overlapping section in the thickness direction of the tubular substrate (Condition 1). Note that m is a value that defines which overlapping sections of the 1st to nth overlapping sections overlap each other in the tubular substrate. For example, if n is 6 (the number of mat layers is 6), then m is any natural number between 3 and 6. Therefore, m can be any value of 3, 4, 5, or 6 as long as it satisfies condition 1 above. Thus, if 3 is selected for m, the first to sixth mats each have first to sixth overlapping sections where both ends overlap, and at least the first and second overlapping sections of the first to sixth overlapping sections must partially overlap in the thickness direction of the tubular substrate. If 4 is selected for m, at least the second and third overlapping sections of the first to sixth overlapping sections must partially overlap in the thickness direction of the tubular substrate. If 5 is selected for m, at least the third and fourth overlapping sections of the first to sixth overlapping sections must partially overlap in the thickness direction of the tubular substrate. Furthermore, if m is set to 6, it is sufficient that at least the 4th and 5th overlapping sections of the 1st to 6th overlapping sections partially overlap in the thickness direction of the tubular substrate. As described above, in a tubular substrate, the number of mats constituting the tubular substrate is limited to three or more, and at least one pair of overlapping portions of the three or more mats must partially overlap in the thickness direction of the tubular substrate.

[0050] (2) In a tubular substrate, if the number of mat layers is n, the k-2nd overlap portion (where k is any natural number between 3 and n) may partially overlap the k-1st overlap portion in the thickness direction of the tubular substrate (Condition 2). Note that k is also a value that defines which overlap portions of the 1st to nth overlap portions overlap each other in the tubular substrate. For example, if n is 5 (the number of mat layers is 5), then k is all natural numbers less than or equal to 3 ≤ k ≤ 5, so all of the above conditions 2 for k = 3, k = 4, and k = 5 must be satisfied. That is, if the tubular substrate has 5 mat layers (n is 5), then the first overlap portion must partially overlap the second overlap portion in the thickness direction of the tubular substrate (when k is 3), the second overlap portion must partially overlap the third overlap portion in the thickness direction of the tubular substrate (when k is 4), and the third overlap portion must partially overlap the fourth overlap portion in the thickness direction of the tubular substrate (when k is 5).

[0051] In the tubular substrate 3 of the above embodiment, n is 6 (the number of mat layers is 6), and k is all natural numbers less than or equal to 3 ≤ k ≤ 6. Therefore, the first overlap portion 311 partially overlaps the second overlap portion 321 in the thickness direction of the tubular substrate (when k is 3), the second overlap portion 321 partially overlaps the third overlap portion 331 in the thickness direction of the tubular substrate (when k is 4), the third overlap portion 331 partially overlaps the fourth overlap portion 341 in the thickness direction of the tubular substrate (when k is 5), and the fourth overlap portion 341 partially overlaps the fifth overlap portion 351 in the thickness direction of the tubular substrate (when k is 6).

[0052] (3) In the above embodiment, the first lap portion 311 to the fifth lap portion 351 are arranged in a stepped manner in a diagonal direction from one side to the other in the thickness direction of the cylindrical substrate 3, as shown in the circumferential cross-sectional view of the cylindrical substrate 3 in Figure 2. However, the arrangement is not limited to this; the first to fifth overlapping sections 311 to 351 may be arranged in a stepped manner in a diagonal direction from one side to the other in the thickness direction of the cylindrical substrate 3. Furthermore, the first to fifth overlapping portions 311 to 351 may be arranged in a zigzag pattern in the thickness direction of the cylindrical base material 3, such as from one side to the other and from the other side to the first side.

[0053] (4) In the above embodiment, the first wrap portion 311 is located at the same position as the sixth wrap portion 361 in the circumferential direction of the cylindrical base material 3. However, the first wrap portion 311 does not have to be positioned at the same location as the sixth wrap portion 361 in the circumferential direction of the cylindrical base material 3. For example, a portion of the other side of the fifth lap portion 351 may overlap with a portion of the one side of the sixth lap portion 361 in the thickness direction of the cylindrical base material 3. That is, the first lap portions 311 to the sixth lap portions 361 may be arranged in a stepped manner in a diagonal direction from one side to the other in the thickness direction of the cylindrical base material 3.

[0054] (5) In the above embodiment, the first overlapping portion 311 to the sixth overlapping portion 361 are arranged such that one end 311a to 361a is positioned inside the other end 311b to 361b. However, the arrangement is not limited to this; the first to sixth overlapping portions 311 to 361 may overlap with one end 311a to 361a positioned outside the other end 311b to 361b. Furthermore, the first to sixth overlapping sections 311 to 361 may overlap without specifying whether one end 311a to 361a or the other end 311b to 361b is positioned on the inside or outside. For example, in the first overlapping section 311, one end 311a may be positioned on the inside of the other end 311b, while in the second overlapping section 321, one end 321a may be positioned on the outside of the other end 321b. [Examples]

[0055] A rehabilitated pipe according to Comparative Example 1, which was made using the cylindrical substrate of Patent Document 1; a rehabilitated pipe according to Example 1, which was made using the cylindrical substrate 3 of the above embodiment; and a rehabilitated pipe according to Example 2, which was described in (4) of the other embodiment, in which the first lap portion is positioned offset from the sixth lap portion in the circumferential direction of the cylindrical substrate without overlapping. All rehabilitated pipes have a bore diameter of φ250.

[0056] Then, the deformation resistance and strength of each rehabilitated pipe were evaluated for Comparative Example 1, Example 1, and Example 2 using flattening tests and other methods described in JSWAS K-1:2002 "Rigid PVC Pipes for Sewerage." It should be noted that, in this study, the tests were not conducted to the point of failure, but rather as non-destructive tests in which the rehabilitated pipes were flattened to a predetermined deflection and then unloaded. As shown in Figure 7, in Example 2, the external force was applied to the rehabilitated pipe at a position corresponding to the first lap portion. On the other hand, in Example 1, the external force was applied to the rehabilitated pipe at a position offset from the position corresponding to the first lap portion. Figure 7 shows the test results.

[0057] According to the above test results, it was confirmed that Examples 1 and 2 were superior to Comparative Example 1 in terms of flexural modulus, flexural strength, and fracture characteristics. Furthermore, it was confirmed that Example 1 was superior to Example 2 in terms of flexural modulus, flexural strength, and fracture characteristics.

[0058] Although embodiments of the present invention have been described above with reference to the drawings, it should be understood that the specific configuration is not limited to these embodiments and examples. The scope of the present invention is indicated not only by the above-described embodiments and examples but also by the claims, and further includes all modifications within the meaning and scope equivalent to the claims. [Explanation of symbols]

[0059] 1 Liner 2 Inner Tubes 3. Cylindrical base material 31-36 Mat 1-6 311-361: Lap 1-6

Claims

1. A cylindrical base material for a lining material that reinforces existing pipelines by lining the inner surface of the existing pipeline, N tubular, fibrous mats (where n is any natural number greater than or equal to 3) are stacked sequentially from the inside to the outside. Each of the first to nth mats has a first to nth overlapping portion formed by overlapping ends, A cylindrical substrate wherein at least the m-2 overlap portion (where m is any natural number between 3 and n) partially overlaps the m-1 overlap portion in the thickness direction of the cylindrical substrate.

2. The cylindrical substrate according to claim 1, wherein the k-2 overlap portion (where k is any natural number from 3 to n) partially overlaps the k-1 overlap portion in the thickness direction of the cylindrical substrate.

3. The cylindrical substrate according to claim 2, wherein the first to n-1th lap portions are arranged in a stepped manner in a diagonal direction in the thickness direction of the cylindrical substrate.

4. The cylindrical substrate according to claim 3, wherein the first wrap portion is arranged at the same position as the n wrap portion in the circumferential direction of the cylindrical substrate.

5. The cylindrical substrate according to any one of claims 1 to 4, wherein the first to nth overlapping portions are each superimposed with one end of the two ends positioned inside the other end.

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