Piping member, piping structure, and method of manufacturing piping member

Abstract

To provide a multilayer pipe that includes a glass fiber layer having a low coefficient of linear expansion.SOLUTION: A multilayer pipe 10 includes a plurality of tubular layers. Specifically, the multilayer pipe 10 includes a polyolefin resin layer 11 that is like a tube and is composed of a polyethylene resin, and a glass fiber layer 12 that is like a tube and is composed of a polyethylene resin and glass fibers. Outside the polyolefin resin layer 11, lies the glass fiber layer 12; and the glass fiber layer 12 constitutes the outermost layer.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a multi-layer pipe. [Background technology]

[0002] Conventionally, steel pipes that have excellent heat resistance and pressure resistance have been used as hot and cold water piping for air conditioning. However, the steel pipes are heavy and difficult to install. In addition, the steel pipes have a problem of being susceptible to corrosion.

[0003] Therefore, resin pipes using various resins have been used as hot and cold water piping. For example, a resin pipe having a first polyolefin resin layer containing a polyethylene resin, a polyolefin resin layer containing glass fiber, and a second polyolefin resin layer containing a polyethylene resin, with a glass fiber layer disposed outside the first polyolefin resin layer, and with the second polyolefin resin layer disposed outside the glass fiber layer, is known (see, for example, Patent Document 1). Such a resin pipe is formed by extrusion molding. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6574546 Summary of the Invention [Problem to be solved by the invention]

[0005] When the above-mentioned resin pipe is extrusion molded, the polyolefin resin layer is on the outside of the glass fiber layer, so that the glass fiber layer is less susceptible to shear forces during extrusion molding, and as a result, the glass fibers contained in the glass fiber layer are less likely to be oriented, so that it is difficult to achieve the effect of reducing the linear expansion coefficient and improving pressure resistance that are expected from the blending of glass fibers.

[0006] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a multi-layer pipe including a glass fiber layer having a low linear expansion coefficient or high pressure resistance. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention has the following aspects. [1] A multi-layer pipe having a plurality of tubular layers, the multi-layer pipe comprising: a tubular polyolefin resin layer containing a polyolefin resin; and a tubular glass fiber layer containing a polyolefin resin and glass fiber, the glass fiber layer being positioned outside the polyolefin resin layer, and the glass fiber layer being the outermost layer. [2] A multi-layer pipe having a plurality of tubular layers, comprising: a tubular polyolefin resin layer containing a polyolefin resin; and a tubular glass fiber layer containing a polyolefin resin and glass fiber, the glass fiber layer being positioned on the outer side of the polyolefin resin layer, and further comprising an adhesive layer, the adhesive layer being positioned on the outer side of the glass fiber layer, and a gas barrier layer being positioned on the outer side of the adhesive layer. [3] A multi-layer pipe according to [1] or [2], comprising two or more polyolefin resin layers. Effect of the Invention

[0008] According to the present invention, it is possible to provide a multi-layer pipe having a glass fiber layer with a low linear expansion coefficient. [Brief description of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view of a multi-layer tube according to an embodiment of the present invention taken along the tube axis direction of the multi-layer tube; [Diagram 2] 1 is a side view showing a schematic diagram of a multi-layer pipe according to an embodiment of the present invention; [Diagram 3] 1 is a plan view showing a schematic diagram of a multi-layer tube according to an embodiment of the present invention; [Figure 4]1 is a cross-sectional view of a multi-layer tube according to an embodiment of the present invention taken along the tube axis direction of the multi-layer tube; [Diagram 5] 1 is a cross-sectional view of a piping member according to an embodiment of the present invention taken along a pipe axis direction of the piping member; [Figure 6] 1 is a cross-sectional view of a piping member according to an embodiment of the present invention taken along a pipe axis direction of the piping member; [Figure 7] 1 is a cross-sectional view of a piping member according to an embodiment of the present invention taken along a pipe axis direction of the piping member; [Figure 8] 5A to 5C are cross-sectional views showing a method for manufacturing a piping member according to an embodiment of the present invention. [Figure 9] 5A to 5C are cross-sectional views showing a method for manufacturing a piping member according to an embodiment of the present invention. [Figure 10] 5A to 5C are cross-sectional views showing a method for manufacturing a piping member according to an embodiment of the present invention. [Figure 11] 1 is a cross-sectional view of a piping member according to an embodiment of the present invention taken along a pipe axis direction of the piping member. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [Multilayer pipe] A multi-layer pipe according to an embodiment of the present invention comprises a plurality of tubular layers. The plurality of layers are arranged side by side from the inside to the outside in the circumferential direction. A multi-layer pipe according to an embodiment of the present invention comprises a tubular polyolefin resin layer containing a polyethylene resin, and a tubular glass fiber layer containing a polyethylene resin and glass fiber. That is, the pipe wall of the multi-layer pipe according to an embodiment of the present invention comprises a polyolefin resin layer and a glass fiber layer. A multi-layer pipe according to an embodiment of the present invention comprises at least one polyolefin resin layer. A multi-layer pipe according to an embodiment of the present invention comprises a glass fiber layer disposed on the outside of the polyolefin resin layer, and the glass fibers are oriented in the pipe axis direction.

[0011] A multi-layer tube according to one embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a cross-sectional view of a multi-layer tube according to one embodiment of the present invention taken along the tube axis direction of the multi-layer tube. Fig. 2 is a side view of a multi-layer tube according to one embodiment of the present invention. Fig. 3 is a plan view of a multi-layer tube according to one embodiment of the present invention. The multi-layer pipe 10 shown in Figures 1, 2 and 3 includes a polyolefin resin layer 11 and a glass fiber layer 12. The polyolefin resin layer 11 and the glass fiber layer 12 are each tubular. The multi-layer pipe 10 has a pipe axis O1 and a flow path 20 therein.

[0012] The thickness t1 of the multi-layer pipe 10 is preferably 5 mm or more and 20 mm or less.

[0013] The polyolefin resin layer 11 contains a polyolefin resin. The glass fiber layer 12 contains a polyolefin resin and glass fibers.

[0014] The thickness t2 of the polyolefin resin layer 11 is preferably 5% to 40% of the total thickness of the multi-layer pipe 10, and more preferably 10% to 30%.

[0015] As shown in Fig. 3, in the glass fiber layer 12, the glass fibers 15 are oriented in the tube axis O1 direction. Here, "the glass fibers 15 are oriented in the tube axis O1 direction" means that the angle θ between the longitudinal direction of the glass fibers 15 and the tube axis O1 is 45° or less. Also, "the glass fibers 15 are oriented in the tube axis O1 direction" means that 50% or more of the glass fibers 15 contained in the glass fiber layer 12 have an angle between the longitudinal direction of the glass fibers 15 and the tube axis O1 within the range of 20° to 70°.

[0016] The orientation of the glass fibers can be confirmed, for example, by observing the cross section using a scanning electron microscope. The observation conditions are not particularly limited, but may be performed using a scanning electron microscope JSM-6701F manufactured by JEOL Ltd., with a deposition thickness of 10 nm, an acceleration voltage of 15 kV, and a magnification of 25 times. This allows the boundary of the glass fiber layer 12, for example, the boundary between the glass fiber layer 12 and the polyolefin resin layer 11, to be visually confirmed.

[0017] In the multi-layer pipe 10 of this embodiment, the glass fiber content in the glass fiber layer 12 is preferably 1 to 200 parts by mass, more preferably 5 to 150 parts by mass, and even more preferably 10 to 70 parts by mass, relative to 100 parts by mass of polyolefin resin. When the glass fiber content is within the above range, the impact strength, dimensional stability, and gas barrier properties of the multi-layer pipe 10 are further improved.

[0018] The thickness t3 of the glass fiber layer 12 is preferably 60% to 95%, and more preferably 70% to 95%, of the total thickness of the multi-layer pipe 10. When the thickness t3 of the glass fiber layer 12 is equal to or greater than the above lower limit, the concentration of the glass fibers contained in the glass fiber layer 12 can be reduced while the linear expansion coefficient of the multi-layer pipe 10 is sufficiently reduced. When the thickness t3 of the glass fiber layer 12 is equal to or less than the above upper limit, a sufficient thickness of the polyolefin resin layer 11 can be ensured, so that the glass fibers contained in the glass fiber layer 12 are less likely to flow out into cold water or hot water.

[0019] In this embodiment, the glass fiber layer 12 is located outside (on the outer circumferential surface of) a polyolefin resin layer 11 described below, and no other polyolefin resin layer is laminated outside (on the outer circumferential surface of) the glass fiber layer 12. Since no other polyolefin resin layer is laminated outside (on the outer circumferential surface of) the glass fiber layer 12 during extrusion molding of the multi-layer pipe 10, the glass fiber-containing resin composition constituting the glass fiber layer 12 comes into contact with the inner surface of the mold, and the shear force received from the inner surface of the mold tends to orient the glass fibers in the extrusion direction, i.e., in the axial direction of the multi-layer pipe 10.

[0020] In addition, because the adhesive layer 31 and the gas barrier layer 32 described below are laminated on the outer peripheral surface of the glass fiber layer 12 after extrusion from the mold, the presence or absence of these layers does not affect the orientation of the glass fibers in the glass fiber layer 12. In addition, if they are not laminated with the glass fiber layer 12 in the mold by co-extrusion, the outer layer of the glass fiber layer 12 may have another polyolefin resin layer, and a polyolefin resin layer containing carbon black to reduce light transmittance may be laminated on the outer peripheral surface of the glass fiber layer 12.

[0021] (Polyolefin resin) The polyolefin resin contained in the polyolefin resin layer 11 and the glass fiber layer 12 is not particularly limited. As the polyolefin resin, a conventionally known polyolefin resin can be used. The polyolefin resin may be used alone or in combination of two or more kinds.

[0022] Examples of polyolefin resins include polyethylene, polypropylene, polybutene, ethylene-vinyl acetate copolymer, and ethylene-α-olefin copolymer. From the viewpoint of more effectively increasing the strength, dimensional stability, and elongation at high temperatures of the multi-layer pipe 10, polyethylene or polypropylene is preferred. The use of polyethylene can effectively increase the impact resistance, earthquake resistance, and long-term creep properties of the multi-layer pipe 10. The use of polypropylene can maintain the extrusion moldability of the glass fiber layer 12 even if the glass fiber content is increased to increase pressure resistance and reduce the linear expansion coefficient.

[0023] Examples of polyethylene (PE) include LDPE, LLDPE, HDPE, etc. Examples of polypropylene (PP) include homo PP, block PP, random PP, etc. Examples of polybutene include polybutene-1, etc.

[0024] The ethylene-α-olefin copolymer is particularly preferably a copolymer in which ethylene is copolymerized with an α-olefin such as propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, or 1-octene at a ratio of about several mol %.

[0025] The polyolefin resin contained in the polyolefin resin layer 11 and the glass fiber layer 12 may be the same or different.

[0026] (Glass fiber) The fiber length of the glass fiber is preferably 0.05 mm or more and 10 mm or less. The fiber length of the glass fiber before molding is more preferably 1 mm or more and 5 mm or less. When the fiber length of the glass fiber is within the above range, the impact strength and dimensional stability of the multi-layer pipe 10 are further improved.

[0027] The fiber length of a glass fiber means the average length of a plurality of glass fibers.

[0028] The fiber diameter of the glass fiber is preferably 1 μm or more and 30 μm or less, and more preferably 5 μm or more and 20 μm or less. When the fiber diameter of the glass fiber is within the above range, the impact strength, dimensional stability, and gas barrier property of the multi-layer pipe 10 are further improved.

[0029] The fiber diameter of the glass fiber is determined by determining the maximum diameter of one glass fiber and averaging the maximum diameters of a plurality of glass fibers.

[0030] From the viewpoint of effectively increasing the impact strength, dimensional stability, and gas barrier properties of the multi-layer pipe 10, it is preferable that the glass fiber is surface-treated with a surface treatment agent. As the surface treatment agent, a silane coupling agent is preferable. As the surface treatment agent, for example, methacrylsilane, acrylic silane, amino silane, imidazole silane, vinyl silane, epoxy silane, etc. are mentioned. From the viewpoint of effectively increasing the impact strength, dimensional stability, and gas barrier properties of the multi-layer pipe 10, it is preferable that the glass fiber is surface-treated with amino silane.

[0031] By surface-treating the glass fiber with aminosilane, the impact strength, dimensional stability, and gas barrier properties of the multi-layer pipe 10 are further improved compared to when the glass fiber is not surface-treated or when the glass fiber is surface-treated with a surface treatment agent other than aminosilane.

[0032] (Compatibilizer) From the viewpoint of effectively enhancing the impact strength, dimensional stability and gas barrier properties of the multi-layer pipe 10, it is preferable that the glass fiber layer 12 contains a compatibilizer.

[0033] Examples of the compatibilizer include maleic acid-modified polyolefin, silane-modified polyolefin, and chlorinated polyolefin. These compatibilizers are not included in the polyolefin resin. The compatibilizer may be used alone or in combination of two or more.

[0034] From the viewpoint of effectively enhancing the impact strength, dimensional stability and gas barrier properties of the multi-layer pipe 10, the compatibilizer is preferably a maleic acid-modified polyolefin or a silane-modified polyolefin, and more preferably a silane-modified polyolefin.

[0035] In the glass fiber layer 12, the content of the compatibilizer relative to 100 parts by mass of the polyolefin resin is preferably 0.1 to 50 parts by mass, more preferably 0.5 to 30 parts by mass, and even more preferably 1 to 15 parts by mass. When the content of the compatibilizer is within the above range, the impact strength, dimensional stability, and gas barrier properties of the multi-layer pipe 10 are further improved.

[0036] (Other ingredients) The polyolefin resin layer 11 and the glass fiber layer 12 may each contain a thermoplastic resin other than the polyolefin resin. However, when a thermoplastic resin other than the polyolefin resin is used, the content of the thermoplastic resin other than the polyolefin resin in the polyolefin resin layer 11 and the glass fiber layer 12 is preferably less than the content of the polyolefin resin in the polyolefin resin layer 11 and the glass fiber layer 12.

[0037] When using a thermoplastic resin other than the polyolefin resin, the content of the polyolefin resin is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more in a total of 100% by mass of the polyolefin resin and the thermoplastic resin other than the polyolefin resin. The content of the polyolefin resin may be 100% by mass or less (including the total amount), 99.99% by mass or less, or 99.9% by mass or less in a total of 100% by mass of the polyolefin resin and the thermoplastic resin other than the polyolefin resin.

[0038] From the viewpoint of further increasing the durability of the multi-layer pipe 10 at high temperatures and suppressing a decrease in durability due to metals such as copper, the polyolefin resin layer 11 and the glass fiber layer 12 preferably contain an antioxidant. The antioxidants may be used alone or in combination of two or more.

[0039] Examples of the antioxidant include hindered phenol-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, amine-based antioxidants, and lactone-based antioxidants.

[0040] Examples of the hindered phenol-based antioxidant include pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], thiodiethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, N,N'-hexane-1,6-diylbis(2-methyl-2,4-diphenylpropionate), and methyl ethyl bis(2-methyl-2,4-diphenylpropionate). bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide], benzenepropanoic acid, 3,5-bis(1,1-dimethylethyl)-4-hydroxy, C7-C9 side chain alkyl ester, 3,3',3'',5,5',5''-hexa-tert-butyl-a,a',a''-(mesitylene-2,4,6-triyl)tri-p-cresol, 4,6-bis(dodecylthiomethyl)-o-cresol, 4,6- Bis(octylthiomethyl)-o-cresol, ethylene bis(oxyethylene) bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], hexamethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-triphenylphosphine 1,3,5-tris[(4-tert-butyl-3-hydroxy-2,6-xylyl)methyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 2,6-di-tert-butyl-4-[4,6-bis(octylthio)-1,3,5-triazin-2-ylamino]phenol, diethyl[{3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl}methyl]phosphonate, and the like.

[0041] Examples of phosphorus-based antioxidants include tris(2,4-di-tert-butylphenyl)phosphite, tris[2-[[2,4,8,10-tetra-tert-butyldibenzo[d,f][1,3,2]dioxaphosphen-6-yl]oxy]ethyl]amine, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, bis[2,4-bis(1,1-dimethylethyl)-6-methylphenyl]ethyl ester phosphorous acid, and tetrakis(2,4-di-tert-butylphenyl)(1,1-biphenyl)-4,4'-diylbisphosphonite.

[0042] The lactone-based antioxidant may, for example, be a reaction product of 3-hydroxy-5,7-di-tert-butyl-furan-2-one with o-xylene.

[0043] From the viewpoint of further increasing the durability of the multi-layer pipe 10 at high temperatures and suppressing the decrease in durability due to metals such as copper, the antioxidant is preferably a phenol-based antioxidant, and more preferably a hindered phenol-based antioxidant. The phenol-based antioxidant and the hindered phenol-based antioxidant may be used alone or in combination of two or more kinds.

[0044] From the viewpoints of further increasing the durability of the multi-layer tube 10 at high temperatures and suppressing deterioration of durability due to metals such as copper, the antioxidant is preferably 3-(3,5-di-tert-butyl-4-hydroxyphenyl)stearyl propionate or 2,4,6-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)mesitylene. Also, the layer containing an antioxidant preferably contains 3-(3,5-di-tert-butyl-4-hydroxyphenyl)stearyl propionate or 2,4,6-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)mesitylene.

[0045] In 100% by mass of the layer containing the antioxidant, the content of the antioxidant, the phenolic antioxidant, and the hindered phenolic antioxidant is preferably 0.01% by mass or more and 5% by mass or less, more preferably 0.1% by mass or more and 1% by mass or less, and even more preferably 0.1% by mass or more and 0.5% by mass or less. When the content of the antioxidant, the phenolic antioxidant, and the hindered phenolic antioxidant is equal to or more than the lower limit, the durability of the multilayer tube 10 at high temperatures is further increased. Even if the content of the antioxidant, the phenolic antioxidant, and the hindered phenolic antioxidant exceeds the upper limit, the durability of the multilayer tube 10 at high temperatures remains unchanged. Therefore, when the content of the antioxidant, the phenolic antioxidant, and the hindered phenolic antioxidant is equal to or less than the upper limit, the use of an excessive amount of the antioxidant is suppressed.

[0046] The polyolefin resin layer 11 and the glass fiber layer 12 in the multi-layer pipe 10 may contain additives such as a crosslinking agent, a copper inhibitor, a lubricant, a light stabilizer, a pigment or a dye, if necessary. In particular, since the multi-layer pipe 10 of this embodiment has an outermost glass fiber layer, which has high light transmittance, it is preferable that the glass fiber layer 12 contains a pigment or dye.

[0047] Examples of the crosslinking agent include organic peroxides. Examples of the organic peroxides include dicumyl peroxide, diisopropylbenzene hydroperoxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne, etc. The crosslinking agent may be used alone or in combination of two or more.

[0048] The amount of organic peroxide used is not particularly limited. When an organic peroxide is used, the content of the organic peroxide in the layer containing the organic peroxide is preferably 0.01 parts by mass or more and 2 parts by mass or less, more preferably 0.01 parts by mass or more and 1 part by mass or less, relative to 100 parts by mass of the polyolefin resin.

[0049] The lubricant is not particularly limited, and examples thereof include fluorine-based lubricants, paraffin wax-based lubricants, stearic acid-based lubricants, etc. The lubricants may be used alone or in combination of two or more kinds.

[0050] The amount of the lubricant used is not particularly limited. In the layer containing the lubricant, the content of the lubricant per 100 parts by mass of the polyolefin resin is preferably 0.01 parts by mass or more and 3 parts by mass or less.

[0051] The light stabilizer is not particularly limited, and examples thereof include salicylic acid ester-based, benzophenone-based, benzotriazole-based, and cyanoacrylate-based ultraviolet absorbers, hindered amine-based light stabilizers, etc. The light stabilizers may be used alone or in combination of two or more.

[0052] The pigment is not particularly limited, and examples thereof include organic pigments such as azo-based, phthalocyanine-based, threne-based, and dye lake-based pigments, and inorganic pigments such as oxide-based, carbon black, molybdenum chromate-based, sulfide-selenide-based, and ferrocyanide-based pigments. One type of pigment may be used alone, or two or more types may be used in combination.

[0053] The multi-layer pipe 10 of this embodiment includes a polyolefin resin layer 11 containing polyethylene resin and a glass fiber layer 12 containing polyethylene resin and glass fiber, and the glass fiber layer 12 is disposed on the outside of the polyolefin resin layer 11. Since the glass fibers are oriented in the direction of the pipe axis O1, a multi-layer pipe having a glass fiber layer with a low linear expansion coefficient can be provided. Therefore, the multi-layer pipe 10 of this embodiment can provide a multi-layer pipe with excellent heat resistance.

[0054] The linear expansion coefficient of the multilayer tube 10 is 2×10 -5 / ℃ or more 9×10 -5 / °C or less, and 2×10 -5 / ℃ or more 8×10 -5 / °C or less, and more preferably 3×10 -5 / ℃ or more 7×10-5 / ° C. or less. When the coefficient of linear expansion of the multi-layer pipe 10 is equal to or more than the above lower limit, the multi-layer pipe 10 has excellent moldability. When the coefficient of linear expansion of the multi-layer pipe 10 is equal to or less than the above upper limit, the multi-layer pipe 10 shrinks little when hot or cold water is passed through it.

[0055] The pressure resistance of the multi-layer pipe 10 is 4.0 MPa or more, preferably 4.5 MPa or more, more preferably 5 MPa or more, and most preferably 6 MPa or more. The pressure resistance can be measured by a breaking water pressure evaluation in accordance with the PWA (Polyethylene Pipe System for Building Equipment) 001 standard.

[0056] <Other embodiments> It should be noted that the present invention is not limited to the above-described embodiment.

[0057] For example, a modified multi-layer pipe 30 as shown in Fig. 4 may be used. In the modified multi-layer pipe 30, the same components as those in the above embodiment are denoted by the same reference numerals, and their description will be omitted, with only the differences being described.

[0058] A multi-layer pipe 30 according to a modified example shown in Fig. 4 includes a polyolefin resin layer 11, a glass fiber layer 12, an adhesive layer 31, and a gas barrier layer 32. The adhesive layer 31 is disposed on the outside (outer periphery) of the glass fiber layer 12. The gas barrier layer 32 is disposed on the outside (outer periphery) of the adhesive layer 31.

[0059] (adhesive layer) The adhesive layer 31 only needs to have the property of adhering the gas barrier layer 32, and is formed from an appropriate material that exhibits adhesive properties. A known adhesive can be used as the material for the adhesive layer 31. Examples of the adhesive include modified polyolefin adhesives, acrylic adhesives, special synthetic rubber adhesives, synthetic resin adhesives, and rubber adhesives.

[0060] The thickness of the adhesive layer 31 is preferably 0.01 mm or more and 1 mm or less, and more preferably 0.02 mm or more and 0.5 mm or less.

[0061] (Gas barrier layer) The gas barrier layer 32 is formed of an appropriate material that exhibits gas barrier properties as long as it has gas barrier properties. Examples of the material for the gas barrier layer 32 include ethylene-vinyl alcohol resin, polyvinyl alcohol, polyamide, polyethylene terephthalate, etc. The material for the gas barrier layer 32 may be one type alone or two or more types in combination.

[0062] From the viewpoint of further improving the gas barrier property of the multi-layer pipe 10, the gas barrier layer 32 preferably contains an ethylene-vinyl alcohol resin. The material of the gas barrier layer 32 is preferably an ethylene-vinyl alcohol resin. The ethylene content in the ethylene-vinyl alcohol resin is preferably 20 mol % or more and 50 mol % or less, and more preferably 30 mol % or more and 40 mol % or less. When the ethylene content is equal to or more than the lower limit, the moldability when molding the gas barrier layer 32 and the water resistance of the gas barrier layer 32 are further improved. When the ethylene content is equal to or less than the upper limit, the gas barrier property of the gas barrier layer 32 and the multi-layer pipe 10 are further improved.

[0063] The thickness of the gas barrier layer 32 is preferably 0.01 mm or more and 1 mm or less, and more preferably 0.5 mm or more and 0.5 mm or less.

[0064] Further, another resin layer may be laminated on the inside of the polyolefin resin layer 11 (on the inner peripheral surface of the polyolefin resin layer 11). Furthermore, it is not necessary to provide the polyolefin resin layer 11. By not providing the polyolefin resin layer 11, the inner peripheral surface of the glass fiber layer 12 receives a shear force from the mold, which makes it easier to orient the glass fibers. Furthermore, glass fibers may be contained in the polyolefin resin layer 11. By laminating a plurality of polyolefin resins containing glass fibers, the glass fibers are oriented in the extrusion direction by the time the molds join, so that the glass fibers are more likely to be oriented in the extrusion direction than when the glass fiber layer 12 is a single resin layer.

[0065] Furthermore, the orientation direction of the glass fibers does not have to be the tube axis O1 direction. The glass fibers may be oriented in the circumferential direction of the multilayer tube 10 (direction perpendicular to the tube axis O1) by rotating the extrusion molding machine, the mold structure, or the take-off machine. In this case, the shear force from the inner surface of the mold is easily applied to the glass fiber layer 12, and the glass fibers are easily oriented in the circumferential direction. Here, the glass fibers 15 being oriented in the circumferential direction of the multilayer tube 10 (direction perpendicular to the tube axis O1) means that the angle θ between the longitudinal direction of the glass fibers 15 and the plane perpendicular to the tube axis O1 is 45° or less. In addition, the glass fibers 15 being oriented in the tube axis O1 direction means that 50% or more of the glass fibers 15 contained in the glass fiber layer 12 have an angle between the longitudinal direction of the glass fibers 15 and the plane perpendicular to the tube axis O1 within the range of 20° to 70°.

[0066] [Piping components] The multi-layer pipe of the above embodiment can be used for the following piping members. Hereinafter, a piping member according to an embodiment of the present invention will be described with reference to the drawings. Fig. 5 is a cross-sectional view of a piping member according to an embodiment of the present invention taken along the axial direction of the piping member. The piping member 100 shown in Fig. 5 includes a pipe portion 101 and a joint portion 102. The piping member 100 has a pipe axis O2, and has a flow passage 120 therein. The tube portion 101 is composed of the above-mentioned multi-layer tube. The tube portion 101 has a first tube portion 111, a second tube portion 112, and a fusion portion 103 formed between the first tube portion 111 and the second tube portion 112. That is, the tube portion 101 is a fusion tube in which the first tube portion 111 and the second tube portion 112 are joined by fusion via the fusion portion 103. In other words, the tube portion 101 is a resin pipe connector in which the first tube portion 111 and the second tube portion 112 are integrated by fusion via the fusion portion 103. The first tube portion 111 and the second tube portion 112 are each tubular. The fusion portion 103 is formed by fusing the first tube portion 111 and the second tube portion 112, so the fusion portion 103 also has a glass fiber layer. The joint portion 102 is joined to the pipe portion 101. More specifically, the joint portion 102 is joined to one end portion of the pipe portion 101 (one end portion of the first pipe portion 111 (the end portion opposite to the fused portion 103)).

[0067] An inner circumferential bead 104 is formed on the inner circumferential surface of the fusion portion 103 between the first pipe portion 111 and the second pipe portion 112. The first pipe portion 111 and the second pipe portion 112 each have an inner circumferential bead 104. The inner circumferential bead 104 has a first convex portion 104a on the first pipe portion 111 side and a second convex portion 104b on the second pipe portion 112 side. The first pipe portion 111 has the first convex portion 104a. The second pipe portion 112 has the second convex portion 104b. The inner circumferential bead 104 has an inner circumferential bead in the first convex portion 104a portion and an inner circumferential bead in the second convex portion 104b portion.

[0068] An outer peripheral bead 105 is formed on the outer peripheral surface of the fusion portion 103 between the first pipe portion 111 and the second pipe portion 112. The first pipe portion 111 and the second pipe portion 112 each have an outer peripheral bead 105. The outer peripheral bead 105 has a third convex portion 105a on the first pipe portion 111 side and a fourth convex portion 105b on the second pipe portion 112 side. The first pipe portion 111 has the third convex portion 105a. The second pipe portion 112 has the fourth convex portion 105b. The outer peripheral bead 105 has an inner peripheral bead in the third convex portion 105a portion and an inner peripheral bead in the fourth convex portion 105b portion.

[0069] In the first pipe portion 111 in a state in which the first pipe portion 111 and the second pipe portion 112 are connected, a region in which the inner peripheral bead 104 of the first pipe portion 111 is not formed is defined as a region R1a. The region R1a is a region between X1a and X1b in FIG.

[0070] In the second pipe portion 112 in a state in which the first pipe portion 111 and the second pipe portion 112 are connected, a region in which the inner peripheral bead 104 of the second pipe portion 112 is not formed is defined as a region R2a. The region R2a is a region between X2a and X2b in FIG.

[0071] In the first pipe 111 in a state where the first pipe 111 and the second pipe 112 are connected, the end refers to a region from the end face of the first pipe 111 to 3 cm inward in the direction in which the first pipe 111 extends (region R1 in FIG. 5; region R1 is the region between X0 and X1a in FIG. 5). In the first pipe 111 in a state where the first pipe 111 and the second pipe 112 are connected, region R1a refers to a region from the end face of the first pipe 111 to 3 cm inward in the direction in which the first pipe 111 extends (region R1 in FIG. 5) excluding a region where the inner circumferential bead 104 is formed (region R1b in FIG. 5; region R1b is the region between X0 and X1b in FIG. 5). However, when the bead width of the first convex portion 104a is 3 cm or more, in the first tube portion 111 in a state in which the first tube portion 111 and the second tube portion 112 are connected, the end portion refers to a region from the end face of the first tube portion 111 toward the inside in the extension direction of the first tube portion 111 up to the bead width of the first convex portion 104a + 2.5 cm. Generally, the bead width of the first convex portion 104a is less than 2 cm.

[0072] In the second pipe 112 in a state where the first pipe 111 and the second pipe 112 are connected, the end refers to a region from the end face of the second pipe 112 to 3 cm inward in the direction in which the second pipe 112 extends (region R2 in FIG. 5; region R2 is the region between X0 and X2a in FIG. 5). In the second pipe 112 in a state where the first pipe 111 and the second pipe 112 are connected, region R2a refers to a region from the end face of the second pipe 112 to 3 cm inward in the direction in which the second pipe 112 extends (region R2 in FIG. 5) excluding a region where the inner circumferential bead 104 is formed (region R2b in FIG. 5; region R2b is the region between X0 and X1b in FIG. 5). However, when the bead width of the second convex portion 104b is 3 cm or more, in the second tube portion 112 in a state in which the first tube portion 111 and the second tube portion 112 are connected, the end portion refers to a region from the end face of the second tube portion 112 toward the inside in the extension direction of the second tube portion 112 up to the bead width of the second convex portion 104b + 2.5 cm. Generally, the bead width of the second convex portion 104b is less than 2 cm.

[0073] In addition, in the first tube portion 111 before the first tube portion 111 and the second tube portion 112 are connected, the end portion refers to the area extending from the end face of the first tube portion 111 to up to 3 cm inward in the direction in which the first tube portion 111 extends.

[0074] Furthermore, in the second pipe portion 112 before the first pipe portion 111 and the second pipe portion 112 are connected, the end portion refers to the area extending from the end face of the second pipe portion 112 to up to 3 cm inward in the extension direction of the second pipe portion 112.

[0075] In the piping member 100 of this embodiment, at least one of the first pipe portion 111 and the second pipe portion 112 is formed of the above-mentioned multilayer pipe. The first pipe portion 111 and the second pipe portion 112 may have the same configuration or may have different configurations. If they have the same configuration, it is easy to form beads uniformly and easy to manufacture. When the first tube portion 111 and the second tube portion 112 have the same configuration, for example, as shown in Fig. 6, the first tube portion 111 and the second tube portion 112 may have a polyolefin resin layer 131 and a glass fiber layer 130. In this case, in the fusion portion 103, the polyolefin resin layer 131 of the first tube portion 111 and the polyolefin resin layer 131 of the second tube portion 112 are connected to form an inner circumferential bead 104, and the glass fiber layer 130 of the first tube portion 111 and the glass fiber layer 130 of the second tube portion 112 are connected to form an outer circumferential bead 105. Since the first pipe portion 111 connected to the joint portion 102 has the glass fiber layer 130, the pressure resistance and low elasticity of the fiber-containing layer can be imparted to the vicinity of the joint portion 102, making the piping member 100 more excellent in pressure resistance and low elasticity. 7, the first tube portion 111 may be composed of a polyolefin resin layer 131, and the second tube portion 112 may have a polyolefin resin layer 131 and a glass fiber layer 130. In this case, in the fusion portion 103, the polyolefin resin layer 131 of the first tube portion 111 and the glass fiber layer 130 of the second tube portion 112 are connected to each other to form an inner circumferential bead 104, and the polyolefin resin layer 131 of the first tube portion 111 and the glass fiber layer 130 of the second tube portion 112 are connected to each other to form an outer circumferential bead 105. The first pipe section 111 is composed only of a fiber-free layer, which facilitates joining of the joint section 102, which has a complex structure, to the first pipe section 111. For example, when the joint section 102 has a structure in which an in-core is inserted into the first pipe section 111, the first pipe section 111 does not include a fiber-containing layer, which makes it easy to insert the in-core of the joint section 102, and the first pipe section 111 can also be flexibly expanded in diameter and is less likely to break, resulting in a piping member 100.

[0076] The joint part 102 is a mechanical joint that connects pipes with a coupler without welding or gas pressure welding. One end part 102A of the joint part 102 is joined to one end part of the pipe part 101 (one end part of the first pipe part 111 (the end part opposite to the fused part 103)). More specifically, one end part 102A of the joint part 102 is fitted onto one end part of the first pipe part 111. Meanwhile, the other end part 102B of the joint part 102 is open, and has a socket 102C for inserting and connecting another pipe.

[0077] The joint portion 102 may be integrally formed with the first pipe portion 111 by injection molding.

[0078] The joint part 102 may have a single layer structure, a two layer structure, or a three or more layer structure. When the joint part 102 is integrally molded with the first pipe part 111, the joint part 102 and the first pipe part 111 have the same structure. For example, when the joint part 102 has a single layer structure, the first pipe part 111 that is integrally molded also has a single layer structure.

[0079] The joint portion 102 contains the same resin as the first pipe portion 111 and the second pipe portion 112. The resin contained in the joint portion 102 may be the same as or different from the resin contained in the first pipe portion 111 and the resin contained in the second pipe portion 112. Only one type of the above resin may be used, or two or more types may be used in combination.

[0080] The joint part 102 may have a fiber-containing layer, similar to the first pipe part 111 and the second pipe part 112. The above-mentioned fibers may be used alone or in combination of two or more kinds. The above-mentioned fibers may be the same as those in the multilayer pipe described above.

[0081] When the joint portion 102 has a fiber-containing layer, the longitudinal direction of the fibers contained in the fiber-containing layer is not particularly limited, but is preferably inclined toward the tube axis O1 of the tube portion 101.

[0082] According to the piping member 100 of this embodiment, the pipe section 101 has the first pipe section 111 and the second pipe section 112, and at least one of the first pipe section 111 and the second pipe section 112 is composed of the above-mentioned multilayer pipe, so that at least one of the first pipe section 111 and the second pipe section 112 has a glass fiber layer with a low linear expansion coefficient. Therefore, according to the piping member 100 of this embodiment, it is possible to provide a piping member with excellent heat resistance.

[0083] [Manufacturing method for piping components] Hereinafter, a method for manufacturing a piping member according to an embodiment of the present invention will be described with reference to the drawings.

[0084] 8 to 10 are cross-sectional views showing a method for manufacturing a piping member according to one embodiment of the present invention.

[0085] The first pipe portion 111 and the second pipe portion 112 constituting the pipe portion 101 are molded by extrusion molding or the like. When the first tube portion 111 and the second tube portion 112 have a two-layer structure (polyolefin resin layer 131 / glass fiber layer 130), a first resin composition containing the above resin and the above fiber and forming the glass fiber layer 130, and a second resin composition containing the above resin and forming the polyolefin resin layer 131 can be prepared, and any method can be used that is capable of causing the first resin composition and the second resin composition to flow in a direction corresponding to the circumferential direction of the molded tube, without any particular limitation.

[0086] The first pipe portion 111 and the second pipe portion 112 obtained as described above are fused (connected). FIG. 8 is a cross-sectional view that shows a schematic diagram of the first tube portion 111 and the second tube portion 112 before fusion (connection). Using the first tube portion 111 and the second tube portion 112 shown in FIG. 8, the end of the first tube portion 111 and the end of the second tube portion 112 are connected by fusing them together via the state shown in FIG. 9 and FIG. 10 to obtain the tube portion 101.

[0087] The fusion method is not particularly limited, and a conventionally known method can be used. The fusion preferably includes a heating step of heating the end of the first tube portion 111 before connection and the end of the second tube portion 112 before connection, and a crimping step of crimping the heated end of the first tube portion 111 and the heated end of the second tube portion 112. In the heating step, it is preferable to heat the end face of the first tube portion 111 before connection, and it is preferable to heat the end face of the second tube portion 112 before connection. In the above-mentioned crimping step, it is preferable to crimp the end face of the heated first tube portion 111 and the end face of the heated second tube portion 112 together.

[0088] FIG. 9 is a cross-sectional view for explaining the heating step in fusion bonding.

[0089] In the heating step, it is preferable to heat the end of the first tube portion 111 and the end of the second tube portion 112 using the heater H. When heating with the heater H, it is preferable to heat from the end face side of the first tube portion 111 and the end face side of the second tube portion 112.

[0090] The heating temperature in the heating step can be appropriately changed depending on the types of compounding components such as resin contained in the first tube portion 111 and the second tube portion 112. The heating temperature is preferably 230° C. or higher and 250° C. or lower, and more preferably 235° C. or higher and 245° C. or lower.

[0091] The heating time in the heating step can be appropriately changed depending on the types of compounding ingredients such as resin contained in the first tube portion 111 and the second tube portion 112, and the diameters of the first tube portion 111 and the second tube portion 112.

[0092] FIG. 10 is a cross-sectional view for explaining the pressure bonding step in fusion bonding.

[0093] The pressure in the compression bonding step can be changed as appropriate depending on the types of compounded components such as resin contained in the first tube portion 111 and the second tube portion 112. The pressure is preferably 1 MPa or more and 3 MPa or less, and more preferably 1.2 MPa or more and 2.8 MPa or less.

[0094] The crimping time in the crimping step can be changed as appropriate depending on the types of compounding ingredients such as resin contained in first tube portion 111 and second tube portion 112, and the diameters of first tube portion 111 and second tube portion 112.

[0095] As described above, the first tube portion 111 and the second tube portion 112 are connected by fusion to form the fused portion 103, and as shown in Figure 5, a tube portion 1 in which the first tube portion 111 and the second tube portion 112 are connected via the fused portion 103 can be obtained.

[0096] A joint portion 102 is joined to one end portion of the pipe portion 1 obtained as described above (one end portion of the first pipe portion 111 (the end portion opposite to the fused portion 103)) to obtain the piping member 100 shown in FIG. 5.

[0097] <Other embodiments> It should be noted that the present invention is not limited to the above-described embodiment.

[0098] For example, a piping member 200 according to a modified example as shown in Fig. 11 may be employed. In the piping member 200 according to the modified example, the same components as those in the above embodiment are denoted by the same reference numerals, and the description thereof will be omitted, and only the differences will be described.

[0099] A piping member 200 according to a modified example shown in FIG. 11 differs from the piping member 100 described above in the structure of a joint portion 210. The joint part 210 is a mechanical joint. One end 210A of the joint part 210 is connected to one end of the pipe part 1 (one end of the first pipe part 111 (the end opposite to the fused part 103)). More specifically, one end 210A of the joint part 210 is inserted into one end of the first pipe part 111. Furthermore, a pressing ring 220 is fitted onto the outer periphery of one end of the first pipe part 111 to which the one end 210A of the joint part 210 is connected. On the other hand, the other end 210B of the joint part 210 is open, and has a socket 210C for inserting and connecting another pipe.

[0100] Although the embodiment of the present invention has been described in detail above with reference to the drawings, the embodiment is merely an example of the present invention. Therefore, the present invention is not limited to the configuration of the embodiment, and it goes without saying that even if there are design changes within the scope of the present invention, they are included in the present invention. In addition, for example, when multiple configurations are included in each embodiment, it goes without saying that possible combinations of these configurations are included even if not specifically stated. In addition, when multiple examples or modified examples are disclosed as the present invention, it goes without saying that possible combinations of configurations across these are included even if not specifically stated. In addition, it goes without saying that the configurations depicted in the drawings are included even if not specifically stated. Furthermore, when the term "etc." is used, it is used to mean that equivalents are included. EXAMPLES

[0101] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0102] [Example 1] The multi-layer tube 10 was manufactured as follows. A homopolypropylene resin composition (density 0.9 g / cm3, MFR 0.5 g / 10 min (conditions: 230°C, load 2.16 kg)) was prepared as a resin composition for producing the polyolefin resin layer 11, and the same homopolypropylene resin composition as above (density 0.9 g / cm3, MFR 0.5 g / 10 min (conditions: 230°C, load 2.16 kg)) was prepared as a glass fiber-containing resin composition for producing the glass fiber layer 12. 3 20% by weight of glass fibers (average fiber length 3 mm, average fiber diameter 13 μm) and 1% by weight of pigment (both amounts relative to the entire resin composition for producing the glass fiber layer 12) were blended into a resin having an MFR of 0.5 g / 10 min (conditions: 230° C., load 2.16 kg) The resin composition was kneaded using a twin-screw co-rotating extruder to prepare a compound. Molding was performed by co-extrusion using a resin composition for producing the polyolefin resin layer 11 and a glass fiber-containing resin composition for producing the glass fiber layer 12. Specifically, extrusion was performed at an extrusion temperature of 220°C using two single extruders (the extrusion thickness of the single extruder for the polyolefin resin layer 11 was 40 mm, and the extrusion thickness of the single extruder for the glass fiber layer 12 was 75 mm), and shaping was performed using a two-layer tube mold. The extruded multilayer tube 10 was taken up by a take-up machine and cut to a predetermined length to obtain the multilayer tube 10. The resulting multi-layer pipe 10 had an inner diameter of 71 mm, an outer diameter of 89 mm, a polyolefin resin layer 11 having a thickness of 1.5 mm, and a glass fiber layer 12 having a thickness of 6.5 mm.

[0103] [Example 2] A multi-layer pipe 10 was obtained in the same manner as in Example 1, except that the take-up machine was rotated.

[0104] [Comparative Example 1] A multi-layer pipe 10 was obtained in the same manner as in Example 1, except that the same resin composition as the polyolefin resin layer 11 was prepared as the resin composition for the other polyolefin resin layer to be provided on the outer peripheral surface of the glass fiber layer 12, and the resin composition for producing the polyolefin resin layer 11 and the other polyolefin resin layers, and the glass fiber-containing resin composition for producing the glass fiber layer 12 were used and extruded at an extrusion temperature of 220°C using three single extruders (the extrusion thickness of the single extruders for the polyolefin resin layer 11 and the other polyolefin resin layers was 40 mm, and the extrusion thickness of the single extruder for the glass fiber layer 12 was 75 mm), and shaped using a three-layer pipe mold. The resulting multi-layer pipe 10 had an inner diameter of 71 mm, an outer diameter of 89 mm, a polyolefin resin layer 11 having a thickness of 1.5 mm, a glass fiber layer 12 having a thickness of 5.0 mm, and the other polyolefin resin layers having a thickness of 1.5 mm.

[0105] [Linear expansion coefficient] The linear expansion coefficient was determined as follows. The multi-layer pipe 10 was cut to a length of about 1000 mm, and after curing for 24 hours in a thermostatic chamber set at 60°C (Thot), the length (Lhot) of the multi-layer pipe was measured. The same multi-layer pipe was then cured for 24 hours in a thermostatic chamber set at 5°C (Tcool), and the length (Lcool) of the multi-layer pipe was measured. The obtained value was substituted into the following formula (1) to determine the linear expansion coefficient.

[0106]

number

[0107] [Pressure resistance evaluation] A burst water pressure evaluation was carried out in accordance with PWA (Polyethylene Pipe System for Building Equipment Research Association Standard) 001. In other words, a test piece of 1000 mm in length was cut from a resin pipe, and the inside of the pipe was filled with room temperature (23°C) water, which was then pressurized by continuously pouring water in at a constant rate, to determine the water pressure (MPa) at which the resin pipe burst.

[0108] [Glass fiber orientation] A cross section of the multilayer tube 10 cut through the thick wall at a plane including the tube axis O1 and a cross section cut at a plane perpendicular to the tube axis O1 were visually observed using a JEOL scanning electron microscope JSM-671F under conditions of a deposition thickness of 10 nm, an acceleration voltage of 15 kV, and a magnification of 25x, to confirm the presence, angle, and ratio of glass fibers in the tube axis O1 and in the direction perpendicular to the tube axis O1.

[0109] (Linear expansion coefficient evaluation) The linear expansion coefficient was measured by the above-mentioned method for each of the multi-layer pipes of Examples 1 and 2, and Comparative Example 1. The results are shown in Table 1.

[0110] [Table 1] [Explanation of symbols]

[0111] 10,30 multilayer pipe 11 Polyolefin resin layer 12 Glass fiber layer 20 Flow Path 31 Adhesive layer 32 Gas barrier layer 100,200 Piping materials 101 Pipe section 102,210 Joint 103 Fusion part 104 Inner bead 105 Outer bead 111 First Pipe 112 Second Tube 115 Glass Fiber 120 Channel 130 Glass fiber layer 131 Polyolefin resin layer 220 Retaining ring

Claims

1. A pipe section and a joint section joined to the pipe section (excluding those having an electric fusion joint in which a coil that generates heat when current is passed through is embedded), The joint portion has a socket to which another pipe is connected, The pipe portion includes a first pipe portion integrally molded with the joint portion, a second pipe portion having a plurality of tubular layers, and a fusion portion formed between the first pipe portion and the second pipe portion, The fused portion has an outer peripheral bead formed thereon that protrudes from the outer surface of the pipe portion, the second pipe portion is tubular and includes a polyolefin resin layer containing a polyolefin resin, and a glass fiber layer laminated on the outside of the polyolefin resin layer and containing a polyolefin resin and a glass fiber; A piping member, wherein the glass fiber layer is an outermost layer of the second pipe portion forming the outer circumferential bead.

2. A piping component as described in Claim 1, wherein the polyolefin resin is a polypropylene resin.

3. A piping member as described in claim 1 or 2, wherein the thickness of the polyolefin resin layer relative to the total thickness of the second pipe portion is 5% or more and 40% or less, and the thickness of the glass fiber layer relative to the total thickness of the second pipe portion is 60% or more and 95% or less.

4. A piping member described in any one of claims 1 to 3, wherein the glass fiber layer contains carbon black.

5. A piping structure comprising a piping member described in any one of claims 1 to 4 and another pipe connected to the joint portion of the piping member.

6. A method for manufacturing a piping member comprising a pipe section and a joint section joined to the pipe section (excluding those comprising an electrofusion joint having an embedded coil that generates heat when electricity is passed through it), comprising: The joint portion has a socket to which another pipe is connected, The pipe portion includes a first pipe portion integrally molded with the joint portion, a second pipe portion having a plurality of tubular layers, and a fusion portion formed between the first pipe portion and the second pipe portion, the second pipe portion is tubular and includes a polyolefin resin layer containing a polyolefin resin, and a glass fiber layer laminated on the outside of the polyolefin resin layer and containing a polyolefin resin and glass fiber; a step of heating an end surface of the first pipe portion integrally molded with the joint portion; heating an end surface of the second tube portion; a crimping step of crimping the heated end surface of the first pipe portion and the heated end surface of the second pipe portion together, A method for manufacturing a piping component.

7. A method for manufacturing a piping component as described in Claim 6, wherein the pressure in the crimping process is 1 MPa or more and 3 MPa or less.

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