JP2020051592A - Electric fusion joint, piping structure and method for producing electric fusion joint - Google Patents

Abstract

To provide an electric fusion joint that can easily identify a use of a joint, a piping structure and a method for producing an electric fusion joint.SOLUTION: An electric fusion joint 1 has a joint body 10, and an identification member 30 fitted to the outer surface of the joint body 10. The identification member 30 has a color difference (ΔE) from the joint body 10 of 1 or more, and can identify a use of a joint on the basis of a color of the identification member 30.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electric fusion joint, a piping structure, and a method for manufacturing an electric fusion joint.

2. Description of the Related Art Conventionally, when connecting a synthetic resin gas pipe or water and sewage pipe, a technique is known in which an electric welding joint in which a heating wire is embedded is energized and fused for connection.
When a synthetic resin pipe is connected by fusion, conditions (fusion conditions) such as a voltage and a time optimal for fusion differ depending on a characteristic of the resin, a diameter and a wall thickness of the pipe, and the like.
The fusion condition differs depending on the type of the pipe or the joint, and a fusion management tag in which information on the fusion condition is recorded is attached to the electric fusion joint (for example, see Patent Document 1).

JP 2009-92111 A

Piping and fitting bodies are color-coded according to their types.
However, the joints are not always given the same color as the pipes for the same application, and it is desired to easily identify the application of the joint regardless of the color of the joint main body.

  Therefore, an object of the present invention is to provide an electric fusion joint, a piping structure, and a method for manufacturing an electric fusion joint, which can easily identify the purpose of the joint.

In order to solve the above problems, the present invention has the following aspects.
[1] A joint body and an identification member attached to an outer surface of the joint body, wherein the identification member has a color difference (ΔE) of 1 or more from the joint body, and is based on a color of the identification member. Electrofusion joints that can identify the purpose of the joint.
[2] The electrofusion joint according to [1], wherein the identification member is at least one selected from a barcode, a barcode mount, a tag for attaching a barcode, a terminal cover, and a terminal cover portion.
[3] The electric fusion joint according to [1] or [2], a cylindrical main body, and one or more identification layers integrally formed on an outer surface of the main body and extending in a tube axis direction of the main body. A piping structure comprising: a resin pipe provided with a resin pipe, wherein a color difference (ΔE) between the identification member and the identification layer is 10 or less.

[4] The method for producing an electro-fusion joint according to [1] or [2], further comprising a step of attaching the identification member to an outer surface of the joint body.

  According to the electrofusion joint of the present invention, the use of the joint can be easily identified.

It is a perspective view showing the electric fusion joint concerning one embodiment of the present invention. FIG. 4 is a partial sectional view taken along line II-II of FIG. 3. It is a top view showing the piping structure concerning one embodiment of the present invention. It is a perspective view showing the electric fusion joint concerning other embodiments of the present invention.

[Electrofusion joint]
An electrofusion joint according to the present invention includes a joint body and an identification member attached to an outer surface of the joint body.
Hereinafter, an electric fusion joint according to an embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the electrofusion joint 1 of the present embodiment includes a joint body 10 formed by bending a cylinder at a substantially right angle, and an identification member 30 attached to an outer surface of the joint body 10.
The electric fusion joint 1 includes terminal cover portions 11, 11 protruding from the outer surface of the joint body 10, and indicator pins 14, 14 provided near the terminal cover portions 11, 11.

  Openings 25 and 26 are formed at both ends of the joint body 10. The joint body 10 includes receiving portions 15 and 16 for receiving piping. A clamp portion 18 is formed integrally with the receiving portion 15 from the opening end 15a of the receiving portion 15 to the outside of the joint body 10 in the axial direction. A clamp portion 18 is formed integrally with the receiving portion 16 outward from the opening end 16a of the receiving portion 16 in the axial direction of the joint body 10.

The clamp portion 18 has a first clamp portion 18a and a second clamp portion 18b which are divided into upper and lower halves. In the receiving portion 15, the first clamp portion 18a and the opening end 15a are connected by a connecting portion 20. The second clamp portion 18b and the open end 15a are connected by a connecting portion 20.
In the receiving portion 16, as in the receiving portion 15, the first clamp portion 18 a and the opening end 16 a are connected by the connecting portion 20. The second clamp portion 18b and the open end 16a are connected by a connecting portion 20.

Opposite portions 19a and 19b are formed at both ends of the first clamp portion 18a and the second clamp portion 18b, respectively. The clamp part 18 clamps the pipe inserted into the receiving part 15 or 16 by bringing the opposing parts 19a and 19b closer to each other.
In this embodiment, a screw 22 that is screwed into a through hole (not shown) formed in the facing portions 19a and 19b is used as a means for displacing the facing portions 19a and 19b in a direction approaching each other. That is, by inserting and turning a screw 22 that fits the through hole from the upper end of the through hole formed in the facing portions 19a and 19b, the screw 22 is screwed into the through hole. As a result, the opposing portion 19a is displaced downward and the opposing portion 19b is displaced upward, so that the opposing portions 19a and 19b approach each other.

  Means for displacing the opposing portions 19a and 19b in directions approaching each other may be other than the screw 22 described above. For example, even if a wire or a SUS band is inserted into the through hole and tightened, the pipe can be firmly clamped by the first clamp portion 18a and the second clamp portion 18b.

The identification member 30 of the present embodiment is a barcode mount 32 on which a barcode 31 is printed. By reading the barcode 31 printed on the barcode mount 32 with a barcode scanner (not shown) or the like, information such as fusion conditions can be read.
Information read by a reader / writer or the like includes the welding conditions, manufacturing date, manufacturing location, manufacturer, application, type, and the like of the electrofusion joint 1.
The welding conditions of the electrofusion joint 1 include a voltage, a time, a temperature, a humidity, and the like that are optimal for the welding.
Examples of the use of the electric fusion joint 1 include water supply, sewage, gas, plant, rental, and the like.
Examples of the type of the electric fusion joint 1 include a socket, an elbow, and a cheese.

The color difference (ΔE) between the identification member 30 and the joint body 10 is 1 or more, preferably 5 or more, and more preferably 10 or more. When the color difference is equal to or greater than the lower limit, the operator can easily recognize the identification member 30 during the fusion operation. The upper limit of the color difference is not particularly limited, but is, for example, 100 or less, and is preferably 80 or less for practical use.
Examples of the color difference include a color difference in the L * a * b * color system specified in JIS Z8781-4: 2013.
The color difference can be measured using a spectral color difference meter (Handy type spectral color difference meter “NF333” manufactured by Nippon Denshoku Industries Co., Ltd.), and is preferably measured in a darkened environment such as a dark room.
Here, the color difference (ΔE) is calculated by the following equation.
ΔE = √ ((L ₁ −L ₂ ) ² + (a ₁ −a ₂ ) ² + (b ₁ −b ₂ ) ² ) (1)
In the equation (1), L ₁ , a ₁ , and b ₁ represent the lightness L, the chromaticity a in the red direction, and the chromaticity b in the yellow direction of the identification member 30, respectively, and L ₂ , a ₂ , and b ₂ are The lightness L, the chromaticity a in the red direction, and the chromaticity b in the yellow direction of the joint body 10 are respectively shown.

  The brightness (L *) of the identification member 30 or the joint body 10 in the L * a * b * color system defined in JIS Z8781-4: 2013 is preferably 20 or more. When the brightness (L *) of the identification member 30 or the joint body 10 is 20 or more, the identification member 30 or the joint body 10 can be easily visually recognized even in a dark place such as a pipe space where the electrofusion joint 1 is installed.

The contrast (PCS, Print Contrast Signal) between the barcode 31 and the barcode mount 32 is preferably 0.5 or more, more preferably 0.6 or more, and even more preferably 0.7 or more. When the PCS is equal to or more than the lower limit, the readability of the barcode 31 by the barcode scanner is easily improved. The upper limit of the PCS is not limited, but is, for example, 0.99.
PCS can be measured using the above-mentioned spectral colorimeter and is calculated by the following equation.
PCS = ((reflectivity (%) of barcode mount 32)-(reflectivity (%) of barcode 31)) / (reflectivity (%) of barcode mount 32) (2)

The bar code scanner generally reads the bar code 31 with a red light having a wavelength of 600 to 700 nm. For this reason, the color of the barcode 31 is preferably a color that easily absorbs red light such as black, blue, and green. The color of the barcode mount 32 is preferably a color that easily reflects red light rays such as white, red, and yellow.
As a combination of colors of the barcode 31 and the barcode mount 32, for example, the barcode 31 is black, the barcode mount 32 is red (PCS = 0.94); the barcode 31 is green, and the barcode mount 32 is White (PCS = 0.51); a combination of black barcode 31 and gray barcode mount 32 (PCS = 0.66).

  As shown in FIG. 2, the electrofusion joint 1 of the present embodiment includes a heating wire 17 such as a nichrome wire. The heating wire 17 is embedded in the receiving portions 15 and 16 of the electrofusion joint 1 on the side close to the inner surface in contact with the pipe. When electricity is supplied, the heating wire 17 generates heat and melts the surrounding synthetic resin.

The terminal cover portions 11 and 11 are formed in a cylindrical shape integral with the joint body 10 to protect the internal metal terminals 12 and 12. The terminal covers 11, 11 protrude from side surfaces of the sockets 15, 16 at both ends of the joint body 10.
Since the outer diameters of the terminal cover portions 11 and 11 are determined according to the connector (not shown) of the fusing device, the outer diameters of the terminal cover portions 11 are constant irrespective of the characteristics of the resin of the pipe to be connected, the diameter and the wall thickness, and the like. The size has become.

  The terminals 12, 12 protected by the terminal covers 11, 11 are connected to the heating wires 17 embedded in the receptacles 15, 16, and by connecting a connector of the fusion device to the terminals 12, 12, It is formed so that the heating wire 17 can be energized.

The indicator pins 14 are formed in a thin projection shape integral with the joint body 10. The indicator pins 14 and 14 are formed inside pin holes 13 and 13 provided on side surfaces of the receiving portions 15 and 16. For this reason, the bases of the indicator pins 14 and 14 reach the side near the inner side surface where the heating wire 17 is provided.
In addition, the indicator pins 14 are formed at a small distance in the axial direction of the joint main body 10 from the terminal cover portions 11 so that fusion by the heating wire 17 can be captured.

An identification member 30 is attached to an outer surface of the joint body 10. The position where the identification member 30 is attached is preferably near the center of the joint body 10 from the viewpoint that it is easy to visually recognize and does not hinder the fusion work.
The identification member 30 may be attached to the outer surface of the joint body 10 with a seal, an adhesive, or the like, and the fitting portion 33 is fitted to the terminal cover portion 11 like the electrofusion joint 2 shown in FIG. Then, it may be attached to the outer surface of the joint body 10.
In the identification member 30 shown in FIG. 4, the fitting portion 33, the connecting portion 34, and the barcode mount 32 are integrally formed, and function as a so-called barcode attachment tag 36.
The terminal cover 35 shown in FIG. 2 may be used as the identification member 30. The terminal cover 35 protects the terminal 12 and is formed so as to fit with the terminal cover portion 11.
When the terminal cover 35 is used as the identification member 30, the terminal cover 35 is less likely to peel off from the joint body 10 than the barcode 31 or the barcode mount 32 attached with a seal or an adhesive.
The terminal cover 35 is preferably colored the same as the barcode 31 or the barcode mount 32 described above, from the viewpoint of making the terminal cover 35 more easily visible.
Further, the terminal cover 11 itself may be detachable, the terminal cover 11 may be given the same color as the barcode 31 or the barcode mount 32 described above, and the terminal cover 11 may be the identification member 30. .
One of these identification members 30 may be used alone, or two or more of them may be used in combination.

Examples of the synthetic resin (first resin) constituting the joint body 10 include high-density polyethylene, medium-density polyethylene, crosslinked polyethylene, polypropylene, polyolefin resins such as polybutene, polyphenylene sulfide, polyethylene terephthalate, and vinyl chloride. No.
From the viewpoint of moldability and cost, the first resin is preferably a high-density polyethylene, a medium-density polyethylene, or a cross-linked polyethylene, and more preferably a high-density polyethylene or a medium-density polyethylene.
One of these first resins may be used alone, or two or more thereof may be used in combination.

The mass average molecular weight of the first resin is preferably from 1.0 × 10 ^{2 to} 1.0 × 10 ^6, more preferably from 1.5 × 10 ^{2 to} 3.0 × 10 ⁵ . When the mass average molecular weight is within the above numerical range, the joint body 10 can easily obtain desired physical properties as a joint.
The mass average molecular weight of the first resin is measured according to JIS K 7252-1.

  The content of the first resin is preferably 90% by mass or more and 100% by mass or less based on the total mass of the joint body 10. When the content of the first resin is within the above numerical range, the joint body 10 can easily obtain desired physical properties as a joint.

  The joint body 10 may contain various additives such as an antioxidant, an ultraviolet absorber (UVA), a light stabilizer, and a pigment, in addition to the first resin.

The electric fusion joint 1 can be manufactured, for example, by the following manufacturing method.
First, a wire of the heating wire 17 is wound around a core mold (not shown).
Subsequently, a resin mold (not shown) in which a gate for injecting the resin for the main body is formed is fitted into the core mold around which the heating wire 17 is wound with a gap from the outside.
Subsequently, the resin for the main body is injected into the inside of the resin molding die, and after the injection molding is completed, the resin molding die is removed. Further, the core mold is separated from the injection molded body by separating the core molds from each other along the axial direction. Thereafter, the resin injected into the gate is cut off from the injection molded body to obtain the joint body 10.
The electrofusion joint 1 is obtained by attaching the identification member 30 to the outer surface of the obtained joint body 10 (attachment step).
Examples of the method of the attaching step include a method of attaching the identification member 30 to the outer surface of the joint body 10 with a seal or an adhesive, and a method of attaching the identification member 30 to the outer surface of the joint body 10 by fitting.

  According to the above-described method of manufacturing the electric fusion joint 1, the identification member 30 can be easily attached to the outer surface of the joint main body 10. For this reason, the electrofusion joint 1 can be efficiently and simply manufactured.

The electrofusion joint 1 includes an identification member 30 whose color difference from the joint body 10 is 1 or more. The identification member 30 is given a color indicating the use of the joint body 10, so that the use of the joint can be easily identified regardless of the color of the joint body 10.
In addition, since the color difference between the identification member 30 and the joint body 10 is one or more, the identification member 30 can be easily visually recognized, and the use of the joint can be more easily identified.

[Piping structure]
As shown in FIG. 3, the piping structure S of the present embodiment includes the electrofusion joint 1 and the pipes 41 and 42 inserted into the receiving portions 15 and 16 of the electrofusion joint 1.

The pipe 41 is a resin pipe including a cylindrical main body 43 and one or more identification layers 45 integrally formed on the outer surface of the main body 43 and extending in the pipe axis direction of the main body 43.
The identification layer 45 has a band shape.
The outer diameter of the pipe 41 is formed substantially the same as the inner diameter of the socket 15 of the electrofusion joint 1. The pipe 41 is connected by fitting the end 41 a of the pipe 41 to the socket 15 of the electrofusion joint 1.

The pipe 42 is a resin pipe including a cylindrical main body 44 and one or more identification layers 46 formed integrally with the outer surface of the main body 44 and extending in the tube axis direction of the main body 44.
The identification layer 46 has a band shape.
The outer diameter of the pipe 42 is formed to be substantially the same as the inner diameter of the socket 16 of the electrofusion joint 1. The pipe 42 is connected by fitting the end 42 a of the pipe 42 to the receptacle 16 of the electrofusion joint 1.

The pipes 41 and 42 are formed in a cylindrical shape by a synthetic resin. Examples of the synthetic resin (second resin) that forms the pipes 41 and 42 include the same resin as the synthetic resin (first resin) that forms the joint body 10 described above.
From the viewpoint of moldability and cost, the second resin is preferably a high-density polyethylene, a medium-density polyethylene, or a cross-linked polyethylene, and more preferably a high-density polyethylene or a medium-density polyethylene.
One of these second resins may be used alone, or two or more thereof may be used in combination.

The mass average molecular weight of the second resin is preferably from 1.0 × 10 ^{2 to} 1.0 × 10 ^6, more preferably from 1.5 × 10 ^{2 to} 3.0 × 10 ⁵ . When the mass average molecular weight is within the above numerical range, the physical properties of the main bodies 43 and 44 as pipes are easily obtained.
The mass average molecular weight of the second resin is measured by the same method as the mass average molecular weight of the first resin.

  The content of the second resin is preferably 90% by mass or more and 100% by mass or less based on the total mass of the main bodies 43 and 44. When the content of the second resin is within the above numerical range, the main bodies 43 and 44 can easily obtain desired physical properties as piping.

  The main bodies 43 and 44 may contain various additives such as an antioxidant, an ultraviolet absorber (UVA), a light stabilizer, and a pigment, in addition to the second resin.

The color difference (ΔE) between the main body 43 and the identification layer 45 in the L * a * b * color system specified in JIS Z8781-4: 2013 is preferably 1 or more, more preferably 5 or more, and further preferably 10 or more. preferable. When the color difference is equal to or more than the lower limit, the main body 43 and the identification layer 45 can be easily distinguished. The upper limit of the color difference is not particularly limited, but is, for example, 100 or less, and is preferably 80 or less for practical use.
The color difference (ΔE) between the main body 44 and the identification layer 46 is the same as the color difference (ΔE) between the main body 43 and the identification layer 45.
The color difference between the pipes 41 and 42 can be measured by the same method as the color difference (ΔE) between the identification member 30 and the joint body 10 described above.
The color difference between the pipes 41 and 42 is calculated by the above-described equation (1).
In the pipe 41, in the formula (1), L ₁ , a ₁ , and b ₁ represent the lightness L of the main body 43, the chromaticity a in the red direction, and the chromaticity b in the yellow direction, respectively, and L ₂ , a ₂ , b ₂ lightness L of each identification layer 45, the red direction chromaticity a, representing a chromaticity b yellow direction.
In the pipe 42, in the formula (1), L ₁ , a ₁ , and b ₁ represent the lightness L of the main body 44, the chromaticity a in the red direction, and the chromaticity b in the yellow direction, respectively, and L ₂ , a ₂ , b ₂ Represents the lightness L of the identification layer 46, the chromaticity a in the red direction, and the chromaticity b in the yellow direction, respectively.

The brightness (L *) of the main body 43 or the identification layer 45 in the L * a * b * color system specified in JIS Z8781-4: 2013 is preferably 20 or more. When the brightness (L *) of the main body 43 or the identification layer 45 is 20 or more, the main body 43 or the identification layer 45 is easily visible even in a dark place such as a pipe space where the pipe 41 is installed.
The brightness (L *) of the main body 44 or the identification layer 46 in the L * a * b * color system specified in JIS Z8781-4: 2013 is preferably 20 or more. When the brightness (L *) of the main body 44 or the identification layer 46 is 20 or more, the main body 44 or the identification layer 46 can be easily recognized even in a dark place such as a pipe space where the pipe 42 is installed.

The resin (third resin) constituting the identification layers 45 and 46 may be the same type of resin as the first resin, or may be a different type of resin. Further, the third resin may be the same type of resin as the second resin, or may be a different type of resin. The third resin is preferably a resin of the same type as the second resin, from the viewpoint of the difficulty in peeling the identification layers 45 and 46 from the outer surfaces of the main bodies 43 and 44.
Examples of the third resin include the same resins as the second resin, and high-density polyethylene, medium-density polyethylene, and cross-linked polyethylene are preferable, and high-density polyethylene and medium-density polyethylene are more preferable.
As the third resin, one type may be used alone, or two or more types may be used in combination.

  The weight average molecular weight of the third resin is the same as the weight average molecular weight of the second resin.

The content of the third resin is preferably 1.0 × 10 ⁻⁵ mass% or more and 10 mass% or less based on the total mass of the identification layers 45 and 46. When the content of the third resin is within the above numerical range, the identification layers 45 and 46 can easily obtain desired physical properties as piping.

  It is preferable that the identification layers 45 and 46 contain an antioxidant from the viewpoint of improving weather resistance. Examples of the antioxidant include a phenolic antioxidant, a phosphorus antioxidant, a sulfur antioxidant, an amine antioxidant, a lactone antioxidant, and the like.

The content of the antioxidant is preferably 10 ppm or more and 5000 ppm or less, more preferably 100 ppm or more and 2000 ppm or less, and more preferably 300 ppm or more and 1500 ppm with respect to the total mass of the identification layers 45 and 46. The following are more preferred. When the content of the antioxidant is equal to or more than the above lower limit, the weather resistance of the identification layers 45 and 46 is easily improved. When the content of the antioxidant is equal to or less than the above upper limit, the balance with the content of other additives is excellent, and the physical properties of the identification layers 45 and 46 are easily improved.
As the antioxidant, one type may be used alone, or two or more types may be used in combination.

It is preferable that the identification layers 45 and 46 contain an ultraviolet absorber (UVA) from the viewpoint of improving weather resistance. Examples of the ultraviolet absorber include a benzophenone ultraviolet absorber, a salmalate ultraviolet absorber, a benzocoat ultraviolet absorber, a benzotriazole ultraviolet absorber, a cyanoacrylate ultraviolet absorber, and a quencher.
As the ultraviolet absorber, for polyethylene or polypropylene, a benzophenone-based ultraviolet absorber and a benzotriazole-based ultraviolet absorber are particularly preferable.
Examples of the benzophenone-based ultraviolet absorber include 2-hydroxy-4-methoxy-benzophenone.
Examples of the benzotriazole-based ultraviolet absorber include 2- (2-hydroxy-5-methylphenyl) benzotriazole (Sumisorb 200, manufactured by Sumika Chemtex Co., Ltd.) and 2- (2-hydroxy-5-t-butyl-5- Methylphenyl) -5-chlorobenzotriazole (Tinuvin 326, BASF), 2- (2-hydroxy-3,5-di-t-butylphenyl) -5-chlorobenzotriazole (Tinuvin 327, BASF), 2 -(2-hydroxy-3,5-di-t-amylphenyl) benzotriazole (Tinuvin 328, manufactured by BASF) and the like.

The content of the ultraviolet absorber is preferably 10 ppm or more and 1000 ppm or less, more preferably 50 ppm or more and 800 ppm or less, further preferably 80 ppm or more and 400 ppm or less based on the total mass of the identification layers 45 and 46. When the content of the ultraviolet absorbent is equal to or more than the lower limit, the weather resistance of the identification layers 45 and 46 is easily improved. When the content of the ultraviolet absorber is equal to or less than the upper limit, the balance with the content of other additives is excellent, and the physical properties of the identification layers 45 and 46 are easily improved.
As the ultraviolet absorber, one type may be used alone, or two or more types may be used in combination.

The identification layers 45 and 46 preferably contain a light stabilizer from the viewpoint of improving weather resistance. Examples of the light stabilizer include salicylic acid ester light stabilizers, benzophenone light stabilizers, benzotriazole light stabilizers, cyanoacrylate light stabilizers, hindered amine light stabilizers (HALS), and the like.
As the light stabilizer, a hindered amine light stabilizer is preferable.
Examples of the hindered amine light stabilizer include tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) butane-1,2,3,4-tetracarboxylate (trade name: ADEKA STAB, manufactured by ADEKA Corporation). LA-52 "), 2,2,6,6-tetramethyl-4-piperidyl methacrylate (trade name" ADEKA STAB LA-87 "manufactured by ADEKA Corporation), bis (2,2,6,6-tetramethyl) -4-piperidyl) sebacate (trade name “ADEKA STAB LA-77Y”, trade name “ADEKA STAB LA-77G”, manufactured by ADEKA Corporation) and the like.

The content of the light stabilizer is preferably from 10 ppm to 1000 ppm, more preferably from 50 ppm to 800 ppm, even more preferably from 80 ppm to 400 ppm, based on the total mass of the discriminating layers 45 and 46. When the content of the light stabilizer is equal to or more than the above lower limit, the weather resistance of the identification layers 45 and 46 is easily improved. When the content of the light stabilizer is equal to or less than the upper limit, the balance with the content of other additives is excellent, and the physical properties of the identification layers 45 and 46 are easily improved.
One type of light stabilizer may be used alone, or two or more types may be used in combination.

The identification layers 45 and 46 may contain carbon black from the viewpoint of improving the weather resistance and the visibility of the pipes 41 and 42. Examples of carbon black include furnace black, acetylene black, channel black, and thermal black.
The content of carbon black is preferably from 1000 ppm to 5.0 × 10 ⁵ ppm, more preferably from 2,000 ppm to 3.0 × 10 ⁵ ppm, more preferably from 20,000 ppm to 1.70, based on the total mass of the identification layers 45 and 46. 0 × 10 ⁵ ppm or less is more preferable. When the content of carbon black is equal to or more than the lower limit, the weather resistance of the identification layers 45 and 46 is improved, and the distinguishability between the main bodies 43 and 44 and the identification layers 45 and 46 is easily improved. When the content of carbon black is equal to or less than the above upper limit, the balance with the content of other additives is excellent, and the physical properties of the identification layers 45 and 46 are easily improved.
One type of carbon black may be used alone, or two or more types may be used in combination.

The identification layers 45 and 46 may contain a coloring agent from the viewpoint of improving the distinguishability between the main bodies 43 and 44 and the identification layers 45 and 46. Examples of the coloring agent include pigments and dyes, and commercially available products can be used.
Examples of the pigment include organic pigments such as azo-based, phthalocyanine-based, selen-based, and dye lake-based; and inorganic pigments such as oxide-based, molybdenum chromate-based, sulfide-selenide-based, and ferrocyanide-based pigments. Can be Among these pigments, those having an absorption wavelength of light of 580 to 800 nm in the visible light range are preferred.
The type and content of the coloring agent can be appropriately determined according to the colors of the main bodies 43 and 44 and the identification layers 45 and 46.
For example, when the main bodies 43 and 44 are blue, the identification layers 45 and 46 are preferably yellow or red, and the content of the coloring agent is preferably 1 ppm or more and 25000 ppm or less based on the total mass of the identification layers 45 and 46. When the content of the coloring agent is equal to or more than the above lower limit, the distinguishability between the main bodies 43 and 44 and the identification layers 45 and 46 is easily improved. When the content of the coloring agent is equal to or less than the above upper limit, the balance with the content of other additives is excellent, and the physical properties of the identification layers 45 and 46 are easily improved.
One type of colorant may be used alone, or two or more types may be used in combination.

In the piping structure S, the color difference between the identification member 30 attached to the outer surface of the joint body 10 and the identification layers 45 and 46 formed on the pipes 41 and 42 is preferably 10 or less, more preferably 5 or less, and more preferably 1 or less. Is more preferred. When the color difference is equal to or less than the upper limit, it is easy to recognize that the applications of the electrofusion joint 1 and the pipes 41 and 42 are the same. As a result, erroneous connection between the electrofusion joint 1 and the pipes 41 and 42 is easily suppressed, and poor connection between the electrofusion joint 1 and the pipes 41 and 42 is easily reduced.
Further, it is preferable that the identification member 30 and the identification layers 45 and 46 have the same system color according to the use of the piping structure S. Since the identification member 30 and the identification layers 45 and 46 are colored in the same system, it is easy to recognize that the applications of the electrofusion joint 1 and the pipes 41 and 42 are the same. Easy to obtain.

In the piping structure S, the pipes 41 and 42 are inserted into the receiving portions 15 and 16 of the electric fusion joint 1, and the heating wire 17 of the electric fusion joint 1 is energized to generate heat. By melting the resin, the receptacle 15 and the pipe 41 are joined, and similarly, the receptacle 16 and the pipe 42 are joined to obtain the resin.
The welding conditions of the electrofusion joint 1 can be appropriately determined according to the size, type, use, and the like of the electrofusion joint 1.

The method of manufacturing the pipes 41 and 42 includes a step of forming the main bodies 43 and 44 and the identification layers 45 and 46 by co-extrusion.
As a manufacturing apparatus of the pipes 41 and 42, for example, a manufacturing apparatus including an extruder, a sizing die, a cooling bath, and a cutting machine can be exemplified. An extruder is a co-extrudable molder. The extruder has at least two feed ports. The sizing die is a cylindrical member whose diameter decreases as it goes downstream. The cooling tank is a device that cools the resin tube having a reduced diameter and hardens the resin. Examples of the cooling tank include a water-cooled cooling tank.

An example of a method for manufacturing the pipes 41 and 42 using the above manufacturing apparatus will be described.
A second resin and, if necessary, an additive (the second resin and the additive may be collectively referred to as a second resin composition) are introduced from one supply port of the extruder. A third resin and an additive (the third resin and the additive may be collectively referred to as a third resin composition) are introduced from another supply port of the extruder. The second resin composition is heated above the melting point of the second resin and kneaded. The third resin composition is heated above the melting point of the third resin and kneaded. Next, the second resin composition and the third resin composition are extruded into a cylindrical shape by an extruder. The second resin composition and the third resin composition flow through different flow paths and then merge, and the third resin composition forms the identification layers 45 and 46.
Thus, a cylindrical molded body in which the identification layers 45 and 46 are integrally formed on the outer surfaces of the main bodies 43 and 44 is obtained.

  Next, the cylindrical molded body is inserted into a sizing die. The cylindrical molded body has a desired thickness as it passes through the sizing die. The cylindrical molded body adjusted to a desired thickness is inserted into the cooling bath. The cooling tank cools the cylindrical molded body and cures the resin. The hardened cylindrical molded body is cut into a desired length to form pipes 41 and 42.

The heating temperature of the second resin composition in the extruder is, for example, preferably from 170 ° C to 250 ° C, and more preferably from 180 ° C to 220 ° C. When the heating temperature is within the above numerical range, good fluidity can be obtained while suppressing thermal decomposition of the second resin.
The heating temperature for the third resin composition in the extruder is the same as the heating temperature for the second resin composition.

  The temperature of the cooling water in the cooling tank is preferably, for example, 20 ° C or more and 30 ° C or less. When the temperature of the cooling water is within the above range, the cylindrical molded body can be sufficiently cured.

  The inner diameters of the main bodies 43 and 44 of the pipes 41 and 42, the thicknesses of the main bodies 43 and 44, the thicknesses of the identification layers 45 and 46, the widths of the identification layers 45 and 46, and the number of the identification layers 45 and 46 are determined by the extruder. It can be adjusted according to the size and shape of the mold and sizing die.

As described above, in the piping structure S of the present embodiment, since the identification member 30 and the identification layers 45 and 46 are colored in the same system, the electrofusion joint 1 and the pipes 41 and 42 are provided. It is easy to recognize that the applications are the same, to suppress erroneous connection between the electrofusion joint 1 and the pipes 41 and 42, and to easily reduce poor connection between the electrofusion joint 1 and the pipes 41 and 42. .
In the piping structure S, as the combination of colors of the identification layers 45 and 46, the joint body 10 and the identification member 30, for example, the identification layers 45 and 46 are red, the color of the joint body 10 is black, and the color of the identification member 30 is Red; identification layers 45 and 46 are green, joint body 10 is white, identification member 30 is green; identification layers 45 and 46 are gray, joint body 10 is black, identification member 30 is gray and the like. Combinations.

The invention is not limited to the embodiments described above.
In the above embodiment, the shape of the electrofusion joint 1 is an elbow. The present invention is not limited to this, and the shape of the electrofusion joint may be a socket or a cheese.
In the above-described embodiment, the electrofusion joint 1 includes the clamp 18. The present invention is not limited to this, and the electrofusion joint may not include the clamp portion.
In the above-described embodiment, the identification layers 45 and 46 are formed in the pipes 41 and 42. The present invention is not limited to this, and the pipe may not have the identification layer. In this case, the identification member and the main body of the pipe are preferably colored in the same system.
In the above-described embodiment, the identification member 30 is any one of the barcode 31, the barcode mount 32, the barcode attachment tag 36, and the terminal cover 35. The present invention is not limited to this, and the identification member only needs to have a color difference of 1 or more from the joint body, and may be a film, a wire, or the like that can be attached to the joint body.

DESCRIPTION OF SYMBOLS 1, 2 Electric fusion joint 10 Joint main body 11 Terminal cover part 12 Terminal 13 Pin hole 14 Indicator pin 15, 16 Reception part 15a, 16a Open end 17 Heating wire 18 Clamp part 18a, 18b Clamp part 19a, 19b Opposition part 20 Connection part 22 Screw 25, 26 Opening part 30 Identification member 31 Barcode 32 Barcode mount 33 Fitting part 34 Linkage part 35 Terminal cover 36 Barcode attachment tag 41, 42 Piping 43, 44 Main body 45, 46 Identification layer S Piping Construction

Claims (4)

A joint body, comprising an identification member attached to the outer surface of the joint body,
The identification member has a color difference (ΔE) of 1 or more from the joint body,
An electrofusion joint that can identify a use of the joint based on a color of the identification member.   The electrofusion joint according to claim 1, wherein the identification member is at least one selected from a barcode, a barcode mount, a barcode attachment tag, a terminal cover, and a terminal cover portion. An electrofusion joint according to claim 1 or 2,
A pipe structure comprising: a tubular main body; and a resin pipe including one or more identification layers integrally formed on an outer surface of the main body and extending in a pipe axis direction of the main body,
A piping structure, wherein a color difference (ΔE) between the identification member and the identification layer is 10 or less.   The method for manufacturing an electro-fusion joint according to claim 1 or 2, further comprising an attaching step of attaching the identification member to an outer surface of the joint body.

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