Resin pipe

Abstract

To provide an easily recyclable resin pipe.SOLUTION: A resin pipe 1 includes a pipe body 10, and a belt-like part 20 extending in a pipe axial direction of the pipe body 10 on an outer peripheral surface of the pipe body 10. The belt-like part 20 is formed integrally with the pipe body 10. A ratio of a width of one belt-like part 20 to the outer periphery of the pipe body 10 is less than 5%. A thickness of the belt-like part 20 is less than that of the pipe body 10, and is 0.02 mm or more and 2.00 mm or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a resin pipe. [Background technology]

[0002] Conventionally, plastic pipes such as polyethylene pipes (polyethylene plastic pipes) have been widely used for a wide variety of purposes, including water pipes and gas pipes. For this reason, plastic pipes are color-coded according to their intended use. As the number of uses for plastic pipes increases, the colors of each pipe tend to become similar even when trying to distinguish them by color tone alone. This creates a problem in that it becomes difficult to distinguish the purpose of a plastic pipe by appearance. It is particularly difficult to distinguish the purpose of a plastic pipe by color tone in dark places.

[0003] To address these problems, for example, Patent Document 1 discloses a resin pipe that is provided with one or more discrimination layers that are integrally formed on the outer surface of the body and extend in the axial direction of the body, and a method for manufacturing the same. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-218999 Summary of the Invention [Problem to be solved by the invention]

[0005] However, there is a problem that the difference in color between the discrimination layer and the resin pipe causes poor color reproduction in recycled resin pipes with discrimination layers. To solve this problem, when recycling resin pipes with discrimination layers, it is preferable to carry out a process of separating the discrimination layer from the resin pipe. In this case, if the circumferential length (width) of each discrimination layer is long, there is a problem that the process of separating the discrimination layer from the resin pipe takes time.

[0006] The present disclosure has been made in consideration of the above circumstances, and aims to provide a resin pipe that can be easily recycled. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention proposes the following means. (1) The resin pipe of the present disclosure comprises a pipe body and a band-shaped portion extending on the outer peripheral surface of the pipe body in the pipe axis direction of the pipe body, the band-shaped portion being integrally formed with the pipe body, the ratio of the width of each of the band-shaped portions to the outer periphery of the pipe body being less than 5%, and the thickness of the band-shaped portion being smaller than the thickness of the pipe body, being 0.02 mm or more and 2.00 mm or less. (2) A plurality of the band-shaped portions are provided in the circumferential direction of the pipe body, and at least some of the band-shaped portions are unevenly arranged in one portion of the circumferential direction of the pipe body. (3) The width of each of the strip portions may be 1 mm or more and 20 mm or less. (4) The total width of the band-shaped portion relative to the outer circumference of the pipe body may be less than 30%. (5) The band-shaped portion may form an angle of 85 degrees or more with respect to a plane perpendicular to the tube axis of the tube body. [Effects of the Invention]

[0008] The present invention can provide a resin pipe that can be easily recycled. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view of a resin pipe according to an embodiment of the present disclosure. [Figure 2] 2 is a cross-sectional view of the resin pipe shown in FIG. 1 taken along line II-II. [Figure 3] FIG. 1 is a side view of a resin pipe according to an embodiment of the present disclosure. [Figure 4] FIG. 10 is a side view showing a case where the band-shaped portion is formed in a spiral shape on the outer peripheral surface of the pipe body. [Figure 5] FIG. 10 is a perspective view of a resin pipe having an uneven distribution portion where a band-shaped portion is unevenly distributed. [Figure 6] FIG. 6 is a cross-sectional view of the resin pipe of the modified example of the present disclosure taken along line II-II in FIG. 5. [Figure 7] FIG. 1 is a diagram schematically illustrating a resin pipe manufacturing apparatus. [Figure 8] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, a resin pipe 1 according to this embodiment will be described with reference to the drawings. FIG. 1 shows a perspective view of a resin pipe 1 according to this embodiment. As shown in FIG. 1, a resin pipe 1 of the present disclosure includes a cylindrical pipe body 10 and a band-like portion 20 formed on the outer surface of the pipe body 10.

[0011] The band-shaped portion 20 is located on the outer surface of the pipe main body 10. The band-shaped portion 20 extends in the direction of the pipe axis O1 of the pipe main body 10. The band-shaped portion 20 is formed integrally with the pipe main body 10. As shown in FIG. 2 , in this embodiment, four band-shaped portions 20 are positioned annularly at 90° intervals around the tube axis O1 of the tube main body 10. The number and arrangement of the band-shaped portions 20 provided in the circumferential direction of the tube main body 10 are not limited. The number of band-shaped portions 20 may be one, two, or three or more. When there are multiple band-shaped portions 20, the band-shaped portions 20 may be arranged at equal intervals in the circumferential direction of the tube main body 10, or some or all of the band-shaped portions 20 may be arranged at unequal intervals.

[0012] The length of the pipe body 10 is determined depending on the application of the resin pipe 1, and is preferably, for example, 2 m or more and 10 m or less. Here, the length of the pipe body 10 is the distance from one open end to the other open end. The inner diameter R1 of the pipe body 10 is determined depending on the application of the resin pipe 1, and is preferably, for example, 10 mm or more and 600 mm or less. The thickness d1 of the pipe body 10 (that is, the length in the radial direction of the resin pipe 1) is determined depending on the use of the resin pipe 1, and is preferably, for example, 1 mm or more and 50 mm or less.

[0013] The color tone of the pipe body 10 is not particularly limited and is determined appropriately depending on the application and purpose.

[0014] The first resin constituting the pipe body 10 is polyethylene. The content of polyethylene in the pipe body 10 is 100 parts by mass per 100 parts by mass of the resin.

[0015] The first resin may be low-density polyethylene, medium-density polyethylene, or high-density polyethylene. Among these, high-density polyethylene is preferred as the first resin. The types of polyethylene are shown in Annex Tables 1 and 2 of JIS K 6922-1:1997. Low-density polyethylene meets the requirements of any of Class 1, Category 1 to Category 6 in Annex 2. The density of low-density polyethylene is 910 kg / m 3 More than 930kg / m 3 is less than. Medium density polyethylene meets the requirements of any of Class 2, Class 1 to Class 5 in Annex 2. The density of medium density polyethylene is 930 kg / m 3 More than 942kg / m 3 is less than. High density polyethylene meets the requirements of any of Class 3, Class 1 to Class 5 in Annex 2. The density of high density polyethylene is 942 kg / m 3 That's all. As shown in Annex Tables 1 and 2, types of polyethylene are classified by a combination of "type" and "class," such as "●type●class."

[0016] The melt flow rate (MFR) of the first resin is, for example, preferably 0.01 g / 10 min or more and 200 g / 10 min or less, more preferably 0.1 g / 10 min or more and 100 g / 10 min or less, even more preferably 0.2 g / 10 min or more and 50 g / 10 min or less, and particularly preferably 0.3 g / 10 min or more and 10 g / 10 min or less. The melt flow rate (MFR) of the first resin is a value measured in accordance with 4.1 (melt flow rate) of Appendix 1 of JIS K 6922-2:2010 at a test temperature of 190°C and a test load of 21.18N.

[0017] The tensile strength of the first resin is preferably 5.9 MPa or more, more preferably 19.6 MPa or more, and even more preferably 25 MPa or more. The upper limit of the tensile strength of the first resin is usually 100 MPa. The tensile strength of the first resin is a value measured in accordance with 4.3 (tensile test) of the appendix of JIS K 6922-2:2010.

[0018] The tensile elongation at break of the first resin is preferably 100% or more, more preferably 300% or more, and the upper limit of the tensile elongation at break of the first resin is usually 1000%. The tensile elongation at break of the first resin is a value measured in accordance with 4.3 (tensile test) of the appendix of JIS K 6922-2:2010.

[0019] The durometer hardness of the first resin is 30H D D or higher is preferable, 60H D D or higher is more preferable, 65H D The upper limit of the durometer hardness of the first resin is usually 200H D It's D. The durometer hardness of the first resin is a value measured in accordance with 4.4 (Durometer D hardness test) of Appendix 1 of JIS K 6922-2:2010.

[0020] The Vicat softening point of the first resin is preferably 65°C or higher, more preferably 90°C or higher, and even more preferably 100°C or higher. The upper limit of the Vicat softening point of the first resin is usually 150°C. The Vicat softening point of the first resin is a value measured in accordance with JIS K 6922-2:2010, Appendix 4.5 (Vicat softening point test).

[0021] The mass average molecular weight of the first resin is 0.5×10 5 Over 10.0 x 10 5 Less than 1.5 x 10 is preferable. 5 Over 3.0 x 10 5 The following is more preferable: If the mass average molecular weight is within the above range, the fluidity of the resin becomes appropriate, and productivity can be increased. The mass average molecular weight of the first resin is measured in accordance with JIS K 7252-1:2008.

[0022] The number average molecular weight of the first resin is 0.1×10 4 Over 2.0 x 10 4 Less than 0.5 x 10 is preferable. 4 Over 1.0 x 10 4 The following is more preferable: If the number average molecular weight is within the above range, the fluidity of the resin becomes appropriate, and productivity can be increased. The number average molecular weight of the first resin is measured in accordance with JIS K 7252-1:2008.

[0023] The glass transition point of the first resin is preferably −140° C. or higher and −90° C. or lower, and more preferably −120° C. or higher and −100° C. If the glass transition point is within the above range, the resin has appropriate fluidity, which increases productivity. The glass transition point of the first resin is a value measured by a differential scanning calorimeter (DSC).

[0024] The melting point of the first resin is preferably 110° C. or higher and 130° C. or lower, and more preferably 120° C. or higher and 125° C. or lower. If the melting point is within the above range, the resin has appropriate fluidity, which increases productivity. The melting point of the first resin is a value measured by a differential scanning calorimeter (DSC).

[0025] The crystallinity of the first resin is preferably 60% to 80%, more preferably 65% ​​to 70%. If the crystallinity is within the above range, the resin has appropriate fluidity, which increases productivity. The crystallinity of the first resin is a value measured by DSC.

[0026] The pencil hardness of the first resin is preferably HB or more and 7B or less, and more preferably HB or more and 6B or less. If the pencil hardness is within the above range, the resin is less susceptible to scratches and the appearance can be further improved. The pencil hardness of the first resin is a value measured in accordance with JIS K 5600-5-4:1999.

[0027] The content of the first resin is preferably 90% by mass or more and 99.99999% by mass or less with respect to the total mass of the pipe body 10.

[0028] The tube body 10 may contain additives such as colorants, antioxidants, ultraviolet absorbers (UVA), and hindered amine light stabilizers (HALS). The content of the additive in the pipe body 10 is determined taking into consideration the type of additive. The content of the additive per 100 parts by mass of the first resin is 1.0 × 10 -5 Parts by mass or more and 10 parts by mass or less are preferred, and 1.0 × 10 -3 Parts by mass or more and 1.0 parts by mass or less are more preferable.

[0029] In this embodiment, the length of the band-shaped portion 20 is the same as the length of the pipe body 10. The length of the band-shaped portion 20 may be the same as or different from the length of the pipe body 10. It is preferable that the length of the band-shaped portion 20 is the same as the length of the pipe body 10.

[0030] The width w2 of the band-shaped portion 20 (i.e., the length of each band-shaped portion 20 in the circumferential direction of the resin pipe 1) is determined appropriately depending on the purpose of the band-shaped portion 20. The ratio of the width w2 to the outer circumference of the resin pipe 1 (the circumferential length around the pipe axis O1) (w2 ratio) is less than 5%. If the width w2 is less than 5%, it is easy to separate the band-shaped portion 20 from the pipe body 10 by grinding or the like during recycling, resulting in excellent recyclability. The w2 ratio is calculated by [width w2 of the band-shaped portion 20]÷[perimeter of the resin pipe 1]×100. The width of the belt-shaped portion 20 is not limited to a specific value, but may be, for example, 1 mm or more and 20 mm or less. From the viewpoint of ensuring visibility, the width of the belt-shaped portion 20 is preferably 2 mm or more. From the viewpoint of improving recyclability, the width of the belt-shaped portion 20 is more preferably 10 mm or less, and even more preferably 4 mm or less.

[0031] When multiple band portions 20 are provided in the circumferential direction as in this embodiment, from the viewpoint of improving recyclability, the total width of the band portions 20 relative to the outer periphery of the pipe body 10 is preferably less than 30%. The total width of the band portions 20 relative to the outer periphery of the pipe body 10 is more preferably less than 20%, and even more preferably less than 15%.

[0032] The thickness d2 of the band-shaped portion 20 (i.e., its length in the radial direction of the plastic pipe 1) is determined appropriately according to the thickness d1 of the pipe main body 10, and is, for example, preferably 0.02 mm or more and 2.00 mm or less, more preferably 0.5 mm or less, and even more preferably 0.2 mm or less. If the thickness d2 is equal to or greater than the above-mentioned lower limit, the strength of the band-shaped portion 20 can be increased. If the thickness d2 is equal to or greater than the above-mentioned lower limit, the color tone of the band-shaped portion 20 can be easily distinguished regardless of the color darkness of the band-shaped portion 20. If the thickness d2 is equal to or less than the above-mentioned upper limit, the thickness of the pipe main body 10 is not too thin at the position of the band-shaped portion 20, and the strength of the pipe main body 10 can be increased. If the thickness d2 is equal to or less than the above-mentioned upper limit, the band-shaped portion 20 disappears when the surface of the plastic pipe 1 is cut during connection with an electric fusion joint, making it easy to confirm that cutting has been performed.

[0033] The inclination of the band-shaped portion 20 with respect to the tube axis O1 of the tube main body 10 will be described with reference to FIGS. As described above, the pipe body 10 and the band-like portion 20 are different in color or material, for example. When recycling such a resin pipe 1, it is necessary to separate the band-like portion 20 from the pipe body 10 before crushing the resin pipe 1. There are no limitations on the method for separating the band-like portion 20 from the pipe body 10. For example, the band-like portion 20 may be removed by grinding the entire circumference of the resin pipe 1, or only the band-like portion 20 may be removed by grinding from the surface of the resin pipe 1.

[0034] FIG. 3 shows a case where the band-shaped portion 20 is parallel to the tube axis O1 of the pipe body 10. On the other hand, as shown in FIG. 4, if the band-shaped portion 20 is not parallel to the tube axis O1 of the pipe body 10 (i.e., is spirally formed), particularly when grinding and removing only the band-shaped portion 20 from the surface of the resin pipe 1, the cutting process takes time, which can reduce recyclability. Therefore, the angle (twist angle) θ of the band-shaped portion 20 with respect to a plane P perpendicular to the tube axis O1 of the pipe body 10 is preferably 85 degrees or more and preferably 90 degrees or less. Note that when the band-shaped portion 20 is arranged along the tube axis O1 of the pipe body 10, the lead angle θ is approximately 90 degrees.

[0035] The color tone of the band-shaped portion 20 is not particularly limited, but it is preferable that it be different from the color tone of the pipe body 10 . The color tone of the band-like portion 20 is different from the color tone of the pipe body 10, thereby creating a striped pattern on the outer periphery of the resin pipe 1. By combining the colors of the band-like portion 20 and the pipe body 10, the color variations of the resin pipe 1 are increased.

[0036] The second resin constituting the strip portion 20 is polyethylene containing low-density polyethylene, medium-density polyethylene, or a mixture thereof. The content of the second resin per 100 parts by mass of the resin in the strip portion 20 is 100 parts by mass.

[0037] The total content of the low-density polyethylene and the medium-density polyethylene per 100 parts by mass of the second resin is preferably 50 parts by mass or more, more preferably 80 parts by mass or more, and even more preferably 100 parts by mass. When the content is equal to or more than the above lower limit, the fluidity of the second resin is easily increased.

[0038] The second resin species and the first resin species may be the same or different. When the type of the second resin is different from the type of the first resin, it is preferable that the density of the second resin is smaller than the density of the first resin. If the density of the second resin is smaller than the density of the first resin, the fluidity of the second resin in the extruder is increased, and an increase in the back pressure of the extruder can be further suppressed. This further reduces the load on the extruder.

[0039] When the type of the second resin is the same as the type of the first resin, it is preferable that the second resin have a larger polyethylene "class" number in Appendix Table 2 of JIS K 6922-1:1997. That is, if the first resin is Class 2, Class 1, it is preferable that the second resin be Class 2, Class 2 to Class 5. By increasing the class number, the fluidity of the second resin in the extruder is improved, and an increase in the back pressure of the extruder can be further suppressed. This further reduces the load on the extruder.

[0040] Preferred examples of the combination of the first resin and the second resin are shown in (a), (b) and (c). (a) The first resin is high density polyethylene and the second resin is medium density polyethylene. (b) The first resin is high density polyethylene and the second resin is low density polyethylene. (c) The first resin is high density polyethylene and the second resin is a blend of low density polyethylene and medium density polyethylene.

[0041] The MFR of the second resin is preferably 0.1 g / 10 min or more and 200 g / 10 min or less, and more preferably 0.4 g / 10 min or more and 100 g / 10 min or less. The MFR of the second resin is preferably greater than the MFR of the first resin. The difference between the MFR of the second resin and the MFR of the first resin is preferably 0.3 g / 10 min or more, more preferably 1.0 g / 10 min or more. If the difference in MFR between the first resin and the second resin is within the above range, the appearance of the band-shaped portion 20 can be further improved and the load on the extruder can be further reduced. The upper limit of the difference between the MFR of the second resin and the MFR of the first resin is, for example, 20 g / 10 min.

[0042] The tensile strength of the second resin is preferably 5.9 MPa or more, more preferably 9.8 MPa or more, and the upper limit of the tensile strength of the second resin is usually 100 MPa. The difference between the tensile strength of the second resin and the tensile strength of the first resin is preferably 5.0 MPa or more, and more preferably 10.0 MPa or more. If the difference in tensile strength between the first resin and the second resin is within the above range, the appearance of the strip portion 20 can be further improved and the load on the extruder can be further reduced. The upper limit of the difference between the tensile strength of the second resin and the tensile strength of the first resin is, for example, 20 MPa.

[0043] The tensile elongation at break of the second resin is preferably 100% or more, more preferably 300% or more, and the upper limit of the tensile elongation at break of the second resin is usually 1000%. The difference between the tensile elongation at break of the second resin and the tensile elongation at break of the first resin is preferably 50% or more, and more preferably 100% or more. If the difference in tensile elongation at break between the first resin and the second resin is within the above range, the appearance of the band-shaped portion 20 can be improved and the load on the extruder can be further reduced. The upper limit of the difference between the tensile elongation at break of the second resin and the tensile elongation at break of the first resin is, for example, 200%.

[0044] The durometer hardness of the second resin is 30H D D or higher is preferred, 45H D The upper limit of the durometer hardness of the second resin is usually 100H D It's D. The difference in durometer hardness between the second resin and the first resin is 15H D D or higher is preferred, 30H D D or higher is more preferable. If the difference in durometer hardness between the first resin and the second resin is within the above range, the appearance of the band-shaped portion 20 can be improved and the load on the extruder can be further reduced. The upper limit of the difference between the durometer hardness of the second resin and the durometer hardness of the first resin is, for example, 50H. D It's D.

[0045] The Vicat softening point of the second resin is preferably 65°C or higher, and more preferably 80°C or higher. The upper limit of the Vicat softening point of the second resin is usually 130°C. The difference between the Vicat softening point of the second resin and the Vicat softening point of the first resin is preferably 5°C or more, more preferably 10°C or more. If the difference in Vicat softening point between the first resin and the second resin is within the above range, the appearance of the belt-shaped portion 20 can be improved and the load on the extruder can be further reduced. The upper limit of the difference between the Vicat softening point of the second resin and the Vicat softening point of the first resin is, for example, 30°C.

[0046] The mass average molecular weight of the second resin is 1.0×10 2 Over 2.0 x 10 5 Less than 1.5 x 10 is preferable. 3 Over 1.5 x 10 5 The following is more preferred: The difference between the mass average molecular weight of the second resin and the mass average molecular weight of the first resin is 1.5 × 10 5 More than 3.0 × 10 is preferable. 5 The above is more preferable. If the difference in mass average molecular weight between the first resin and the second resin is within the above range, the appearance of the strip portion 20 can be improved and the load on the extruder can be further reduced. The upper limit of the difference between the mass average molecular weight of the second resin and the mass average molecular weight of the first resin is, for example, 3.0 × 10 5 is.

[0047] The number average molecular weight of the second resin is 1.0×10 3 Over 10.0 x 10 3 Less than 1.5 x 10 is preferable. 3 Over 5.0 x 10 3 The following is more preferred:

[0048] The glass transition point of the second resin is preferably -135°C or higher and -95°C or lower, and more preferably -125°C or higher and -105°C or lower. The difference between the glass transition point of the second resin and the glass transition point of the first resin is preferably 0°C or more and 10°C or less, more preferably 0°C or more and 5°C or less. If the difference in glass transition point between the first resin and the second resin is within the above range, the appearance of the strip portion 20 can be improved and the load on the extruder can be further reduced.

[0049] The melting point of the second resin is preferably 100°C or higher and 120°C or lower, and more preferably 115°C or higher and 120°C or lower. The difference between the melting point of the second resin and the melting point of the first resin is preferably 0°C or higher and 10°C or lower, more preferably 0°C or higher and 5°C or lower. If the difference in melting point between the first resin and the second resin is within the above range, the appearance of the band-shaped portion 20 can be made better.

[0050] The crystallinity of the second resin is preferably 30% or more and 60% or less, and more preferably 40% or more and 60% or less. The difference between the crystallinity of the second resin and the crystallinity of the first resin is preferably 5% or more, and more preferably 10% or more. If the difference in crystallinity between the first resin and the second resin is within the above range, the appearance of the strip portion 20 can be improved and the load on the extruder can be further reduced. The upper limit of the difference between the crystallinity of the second resin and the crystallinity of the first resin is, for example, 50%.

[0051] The pencil hardness of the second resin is preferably HB or more and 7B or less, and more preferably HB or more and 6B or less. The difference in pencil hardness between the second resin and the first resin is preferably 2B or less, more preferably 1B or less. If the difference in hardness between the first resin and the second resin is within the above range, the appearance of the band-shaped portion 20 can be improved and the load on the extruder can be further reduced.

[0052] The content of the second resin with respect to the total mass of the strip portion 20 is preferably 90% by mass or more and 99.99999% by mass or less.

[0053] The band-shaped portion 20 may contain an additive. The additive contained in the band-shaped portion 20 is the same as the additive contained in the pipe body 10. The additive in the pipe body 10 and the additive in the band-shaped portion 20 may be the same or different. The content of the additive in the strip portion 20 is determined taking into consideration the type of additive. The content of the additive per 100 parts by mass of the second resin is 1.0×10 -5 Parts by mass or more and 10 parts by mass or less are preferred, and 1.0 × 10 -3 Parts by mass or more and 1.0 parts by mass or less are more preferable.

[0054] 3 and 4 show modified examples of the band-shaped portion 20. In this modified example, a plurality of band-shaped portions 20 are provided in the circumferential direction of the pipe body 10, and at least some of the band-shaped portions 20 are unevenly arranged in one part of the circumferential direction of the pipe body 10. As shown in FIG. 5 , in this modification, two uneven distribution portions 30 in which the band-like portions 20 are unevenly distributed are provided on either side of the tube axis O1. Specifically, twelve band-like portions 20 are provided in the circumferential direction, and each uneven distribution portion 30 has six band-like portions 20. The number of uneven distribution portions 30 is not limited to two and may be one, three, or more. When multiple uneven distribution portions 30 are provided, the uneven distribution portions 30 may be provided at equal or uneven intervals in the circumferential direction. The number of band-like portions 20 per uneven distribution portion 30 is not limited as long as it is two or more. The number of band-like portions 20 per uneven distribution portion 30 can be appropriately set depending on the width of the band-like portions 20 and the width of the resin pipe 1. When multiple uneven distribution portions 30 are provided, the number of band-like portions 20 in each uneven distribution portion 30 may be the same or different.

[0055] Furthermore, in this modified example, the spacing between each of the six strip portions 20 in one uneven distribution portion 30 is equal, but the spacing between some or all of the strip portions 20 in one uneven distribution portion 30 may be different.

[0056] The width and thickness d2 of the strip portion 20 are as described above, and therefore will not be described here.

[0057] Regarding the inclination of the band-shaped portion 20 relative to the tube axis O1 of the tube body 10, as mentioned above, it is preferable that the angle θ that the band-shaped portion 20 makes with respect to a plane perpendicular to the tube axis O1 of the tube body 10 is 85 degrees or more, and preferably 90 degrees or less.

[0058] In order to control the inclination of the band-shaped portion 20 with respect to the pipe axis O1 of the pipe body 10, it is preferable to manufacture the resin pipe 1 using the following manufacturing apparatus.

[0059] A manufacturing apparatus for manufacturing the resin pipe 1 will be described. As shown in Fig. 7, the manufacturing apparatus 51 includes a co-extrusion molding machine 52, a cooling section 53, a printing machine 55, a take-up machine 54, and a cutting machine 56. In Fig. 7, a portion of a molding die 52a (described later) that forms a second flow path 52c is indicated by a two-dot chain line so that the inside can be easily seen. The co-extrusion molding machine 52, cooling section 53, printing machine 55, take-up machine 54, and cutting machine 56 are arranged in this order from the upstream side to the downstream side along which the resin pipe 1 (continuous resin pipe 1A described later) is transported.

[0060] A first flow path 52b and a second flow path 52c are formed in a molding die 52a of the co-extrusion molding machine 52. In this embodiment, four second flow paths 52c are formed in the molding die 52a. The four second flow paths 52c merge with the first flow path 52b from the side of the first flow path 52b. A resin material (first resin) for forming the pipe body 10 is supplied in a molten state to the first flow path 52b. A resin material (second resin) for forming the band-shaped portion 20 is supplied in a molten state to the second flow path 52c. A continuous resin pipe 1A is extruded downstream from the molding die 52a. The continuous resin pipe 1A is formed by continuously connecting resin pipes 1 in the direction of the axis C. 8 shows the central axis C1 of the molding die 52a of the co-extrusion molding machine 52 as viewed from the downstream side toward the upstream side. In order to focus on the position of the central axis C1, the molding die 52a is indicated by a two-dot chain line.

[0061] The cooling section 53 is composed of a water tank, etc. The cooling section 53 cools the continuous resin pipe 1A molded by the co-extrusion molding machine 52 using water, etc.

[0062] 8, the haul-off machine 54 has a plurality of endless tracks 58. The plurality of endless tracks 58 are arranged at intervals from one another around a predetermined central axis C2. In this example, the haul-off machine 54 has four endless tracks 58. Each endless track 58 has a plurality of holding members 59. A recess 59a is formed in the center of the width direction (circumferential direction) of each holding member 59. When a drive motor (not shown) is rotated, the portion of the endless track 58 facing the central axis C2 moves downstream or upstream.

[0063] The endless track 58 is supported by support members 61 and the like via a known distance adjustment mechanism 60. Each support member 61 is fixed to a frame or the like (not shown). For example, the distance adjustment mechanism 60 is provided with a lever (not shown). Rotating the lever moves the endless track 58 toward or away from the support members 61, adjusting the distance between the endless track 58 and the central axis C2. The distance adjustment mechanism 60 adjusts the position of the endless track 58 in a first direction D1 toward and away from the central axis C2.

[0064] The multiple endless tracks 58 hold the continuous resin pipe 1A on the central axis C2. At this time, a portion of the outer circumferential surface of the continuous resin pipe 1A fits into the recess 59a of each holding member 59 of the endless tracks 58. This allows the multiple endless tracks 58 to securely hold the continuous resin pipe 1A. The axis C of the continuous resin pipe 1A held by the multiple endless tracks 58 is aligned with the central axis C2. When each of the endless tracks 58 rotates in a predetermined direction, the continuous resin pipe 1A is drawn downstream.

[0065] The haul-off machine 54 may also be provided with a position adjustment mechanism that adjusts the position of the endless tracks 58 in the second direction D2, which is the tangent direction of a circle centered on the central axis C2. With this configuration, if the centers of the multiple endless tracks 58 deviate from the central axis C2, the position adjustment mechanism and the distance adjustment mechanism 60 can be used to adjust the centers of the multiple endless tracks 58 so that they coincide with the central axis C2.

[0066] As described above, the resin pipe 1 of the present disclosure comprises a pipe main body 10 and a band-like portion 20 extending on the outer surface of the pipe main body 10 in the pipe axis O1 direction of the pipe main body 10, the band-like portion 20 being formed integrally with the pipe main body 10, the ratio of the width of each band-like portion 20 to the outer circumference of the pipe main body 10 being less than 5%, and the thickness of the band-like portion 20 being smaller than the thickness of the pipe main body 10, being 0.02 mm or more and 2.00 mm or less. When recycling a resin pipe 1 having a band-like portion 20, it is preferable to separate the band-like portion 20 from the pipe body 10. Separation of the band-like portion 20 from the pipe body 10 is carried out, for example, by grinding the surface of the resin pipe 1. In this case, the time required for grinding to separate the band-like portion 20 from the pipe body 10 varies depending on, for example, the width and thickness of the band-like portion 20. If the width of the band-like portion 20 is large, the grinding range becomes larger and the grinding takes longer. Furthermore, if the thickness of the band-like portion 20 is large, the grinding depth becomes larger and the grinding takes longer. With the above-described configuration, by specifying the thickness of the band-like portion 20 and the width of the band-like portion 20 relative to the outer periphery of the pipe body 10, it is possible to reduce the time required to separate the band-like portion 20 from the pipe body 10 when recycling the resin pipe 1. Therefore, the resin pipe 1 can be easily recycled.

[0067] In addition, multiple band-shaped portions 20 may be provided in the circumferential direction of the pipe body 10, and the arrangement of at least some of the multiple band-shaped portions 20 may be unevenly distributed to a portion of the circumferential direction of the pipe body 10. Although the recyclability can be improved by reducing the width of the belt-like portion 20, the visibility of the belt-like portion 20 may be reduced due to the narrowing of the belt-like portion 20. With the above configuration, at least some of the band-like portions 20 are unevenly distributed in one portion of the circumferential direction of the pipe body 10. As a result, even if the width of each band-like portion 20 is reduced, multiple band-like portions 20 are gathered together in the uneven distribution portion 30, thereby improving visibility. This allows for a resin pipe 1 that is easily recyclable and has excellent visibility.

[0068] Furthermore, the width of each strip portion 20 may be 1 mm or more and 20 mm or less. If the width of each band-like portion 20 is 1 mm or more and 20 mm or less, the width of each band-like portion 20 that needs to be ground when recycling the resin pipe 1 can be reduced. This reduces the time required to separate the band-like portion 20 from the pipe body 10. This makes it possible to produce a resin pipe 1 that is easily recyclable.

[0069] The total width of the band-shaped portion 20 relative to the outer periphery of the pipe body 10 may be less than 30%. If the total width of the band-like portions 20 relative to the outer circumference of the pipe body 10 is less than 30%, the total width of the band-like portions 20 that must be ground when recycling the resin pipe 1 can be reduced. This reduces the time required to separate the band-like portions 20 from the pipe body 10. This allows the resin pipe 1 to be easily recycled.

[0070] The angle θ of the band-shaped portion 20 relative to a plane perpendicular to the tube axis O1 of the tube main body 10 may be 85 degrees or more. If the band-like portion 20 is formed in a spiral shape on the outer peripheral surface of the pipe body 10, it takes time to grind the band-like portion 20 when recycling the resin pipe 1. As described above, if the angle that the band-shaped portion 20 forms with respect to a plane perpendicular to the tube axis O1 of the pipe main body 10 is 85 degrees or more, the band-shaped portion 20 can be ground and removed along the tube axis O1 of the pipe main body 10. This reduces the time required to separate the band-shaped portion 20 from the pipe main body 10. This allows the resin pipe 1 to be easily recyclable.

[0071] One embodiment of the present disclosure has been described above in detail with reference to the drawings, but the specific configuration is not limited to this embodiment, and modifications, combinations, deletions, etc. of the configuration may also be made within the scope that does not deviate from the gist of the present invention.

[0072] For example, in the manufacturing apparatus 51, the printing machine 55 may be disposed between the take-up machine 54 and the cutting machine 56. By configuring the manufacturing apparatus 51 in this manner, twisting of the band-shaped portion 20 with respect to the axis C of the pipe main body 10 can be suppressed. For example, a stencil may be provided on the outer surface of the resin pipe 1. In the above embodiment, the band-shaped portion 20 is integrally formed with the pipe body 10 by co-extrusion molding, but the method of forming the band-shaped portion 20 is not limited to this. For example, after molding the pipe body 10, the band-shaped portion 20 may be formed by printing ink containing a colorant on the outer peripheral surface of the pipe body 10. [Explanation of symbols]

[0073] 1. Resin pipe 10 Tube body 20 Belt 30 Uneven distribution area

Claims

1. A tube body; a band-shaped portion extending in the axial direction of the pipe body on the outer peripheral surface of the pipe body; Equipped with the band-shaped portion is formed integrally with the pipe body, and the ratio of the width of each band-shaped portion to the outer periphery of the pipe body is less than 5%; The thickness of the band-shaped portion is smaller than the thickness of the pipe body, and is 0.02 mm or more and 2.00 mm or less. Resin pipe.

2. The band-shaped portion is provided in a plurality in the circumferential direction of the pipe body, At least some of the band-shaped portions are unevenly arranged in a portion of the circumferential direction of the pipe main body. The resin pipe according to claim 1.

3. The width of each of the strip portions is 1 mm or more and 20 mm or less. The resin pipe according to claim 1 or 2.

4. The total width of the band-shaped portion relative to the outer circumference of the pipe body is less than 30%. The resin pipe according to claim 1 or 2.

5. The band-shaped portion forms an angle of 85 degrees or more with respect to a plane perpendicular to the tube axis of the tube body. The resin pipe according to claim 1 or 2.

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