JP6666775B2 - Electrofusion joint and method of manufacturing electrofusion joint - Google Patents

Description

  The present invention relates to an electric fusion joint and a method for manufacturing the electric fusion joint.

2. Description of the Related Art Conventionally, thermoplastic resin pipes such as pipes containing a polyolefin (PO) resin have been widely used for gas pipes, water pipes, drain pipes, etc. because they have earthquake resistance, flexibility, and corrosion resistance.
When connecting such resin tubes to each other, an electric fusion joint (hereinafter, referred to as an “EF joint”) is frequently used. Specifically, the EF joint includes a joint body made of a thermoplastic resin, and a heating element such as a heating wire embedded in a fusion interface on the inner peripheral surface side of the joint body. Then, with the resin pipes to be connected inserted into the receptacles provided at both ends of the joint body of the EF joint, power is supplied through a power cord to generate heat from the heating element. As a result, the resin on the inner peripheral surface of the receptacle around the heating element and the outer peripheral surface layer of each resin tube are melted, and the electric fusion joint and the two resin tubes are connected to form an integral conduit.

  For example, Patent Literature 1 discloses a pipe (thermoplastic resin pipe, resin pipe) mainly composed of a thermoplastic resin having at least two receptacles to which pipes are connected, a heating wire wound around the receptacle, A pair of connector pins (connector mounting portions) erected on the tubular body in a state where both ends of the heating wire are connected and a part of the bottom is exposed, and at least one end of the heating wire is There is disclosed an electro-fusion type resin pipe joint (EF joint) in which the outer peripheral surface is joined to an exposed part of the bottom of the connector pin.

JP 2005-321034 A

  Generally, an oxygen barrier layer containing, for example, polyvinyl alcohol (PVA) or ethylene vinyl alcohol copolymer (EVOH) is provided on the outer peripheral surface of a pipe containing PO or the like for an air conditioning pipe through which cold water or a refrigerant passes. ing. By providing the oxygen barrier layer, intrusion of oxygen and other gases from the outside to the inside of the pipe is suppressed, and deterioration or failure of a device provided at a destination of cold water or a refrigerant can be prevented. .

  However, conventional EF joints have a problem in that although they have an antioxidant performance due to the addition of an antioxidant containing phenol or the like, the oxygen barrier performance is not oxidized. Therefore, even if the amount is small, oxygen and other gases and the like enter the inside of the EF joint from the outside, and it has not been possible to prevent the deterioration or failure of the device provided at the destination of the cold water or the refrigerant.

  The present invention has been made in view of the above circumstances, and provides an EF joint having oxygen barrier performance and a method of manufacturing an EF joint having oxygen barrier performance.

An EF joint according to the present invention is an electric fusion joint that connects a plurality of resin pipes by fusion by heating, and is a resin-made joint body having a plurality of receptacles and embedded in a fusion-bonded portion of the receptacle. Heating wire, and an oxygen barrier layer provided on the outer peripheral side of the joint body with respect to the heating wire, wherein the oxygen barrier layer covers the heating wire from the outer peripheral side of the joint body. It is embedded in the joint body, the oxygen barrier layer, that provided in a semicircular shape which is convex to the outer peripheral side of the joint body along the outer periphery of the heating wire.

According to the above configuration, since the oxygen barrier layer is provided on the outer peripheral side from the inner peripheral surface of the joint main body, oxygen from the outside to the inside of the hollow part of the joint main body is cut off, and Oxygen intrusion can be prevented. Thereby, oxygen barrier performance is provided to the EF joint.
Further, according to the above configuration, since the oxygen barrier layer is embedded in the resin of the joint main body, the oxygen barrier layer is stably fixed, and the oxygen barrier performance imparted to the EF joint is more stably exhibited.

The method for manufacturing an EF joint according to the present invention includes a resin joint body having a plurality of sockets, a heating wire embedded in a fusion portion of the socket, and a heating wire provided on an outer peripheral side of the joint body with respect to the heating wire. A method for manufacturing an electro-fusion joint, comprising: inserting a resin tube into the receptacle and fusing the same by heating, comprising a plane along an inner peripheral surface of the joint body. the joint body the covering heating wire the heating wire is covered with an oxygen barrier layer, the flat surface of the coated electric wire having a semicircular curved surface which is convex to the outer peripheral side of the joint body from the plane Winding a core mold in a state facing the inner peripheral side of the core, a step of fitting a resin mold with a gap from the outside in the core mold around which the coated heating wire is wound, a step of injecting the resin inside the mold, that have a.

  According to the above configuration, since the oxygen barrier layer is provided in advance on the outer peripheral portion of the heating wire, the heating wire can be wound around the core mold, and the oxygen barrier layer can be arranged on the outer peripheral side of the joint body in the heating wire. In addition, the oxygen barrier performance can be imparted to the EF joint, and the oxygen barrier layer can be formed stably. Therefore, an EF joint having oxygen barrier performance can be manufactured.

  According to the EF joint and the method of manufacturing the EF joint according to the present invention, the EF joint can have oxygen barrier performance.

It is a sectional view showing a first embodiment of an EF joint concerning the present invention. It is sectional drawing which shows 2nd Embodiment of the EF joint which concerns on this invention. It is sectional drawing which shows 3rd Embodiment of the EF joint which concerns on this invention. It is a schematic diagram for explaining the manufacturing method of the EF joint of the third embodiment according to the present invention. It is a side view showing a 4th embodiment of an EF joint concerning the present invention. It is the schematic for demonstrating the manufacturing method of the EF joint of 4th Embodiment concerning this invention. It is a side view showing a 5th embodiment of an EF joint concerning the present invention. It is a figure for explaining the manufacturing method of the EF joint of a 5th embodiment concerning the present invention, (a) is a sectional view showing signs that an inside part of a joint main part is formed, (b) is an oxygen barrier It is sectional drawing which shows a mode that a layer is formed, (c) is sectional drawing which shows a mode that an outer part of a joint main body is formed. It is a sectional view showing the modification of the third embodiment of the EF joint concerning the present invention.

  Hereinafter, embodiments of an EF joint and a method of manufacturing the EF joint to which the present invention is applied will be described with reference to the drawings. The drawings used in the following description are schematic, and the length, width, thickness ratio, and the like are not necessarily the same as actual ones, and can be changed as appropriate.

First, an EF joint 1A according to a first embodiment to which the present invention is applied will be described.
As shown in FIG. 1, the EF joint 1 </ b> A of the first embodiment is an EF joint that connects a plurality of (two in FIG. 1) resin tubes 5 by fusing them by heating, (2) a joint body 2 made of resin (hereinafter referred to as resin for the main body) having a receiving port 7, a heating wire 3 buried in a fusion portion 7 </ b> M of the receiving port 7, An oxygen barrier layer 14 provided on the outer peripheral side.

The resin tube 5 includes a tube main body 22, an adhesive layer 23 provided on the outer peripheral surface of the tube main body 22, and an oxygen barrier layer 24 provided on the outer peripheral surface of the adhesive layer 23. The oxygen barrier layer 24 is provided to prevent intrusion of oxygen, gas, and the like from the outside to the inside of the resin tube 5. The adhesive layer 23 is provided for bringing the tube main body 22 and the oxygen barrier layer 24 into close contact with each other. However, the adhesive layer 23 and the oxygen barrier layer 24 are not provided in a portion of the tube main body 22 that is fitted inside the receiving port 7.
The resin pipe 5 is a thermoplastic resin pipe containing PO or the like. Examples of the PO include PE, polypropylene, polybutene, an ethylene-vinyl acetate copolymer, and an ethylene-α-olefin copolymer.

From the viewpoint that the shock resistance and the earthquake resistance are further enhanced, the tube main body 22 disposed on the innermost side of the resin tube 5 preferably contains 90% by weight or more of the PO-based resin, and contains 95% by weight or more. More preferably, it is 100% by weight (total amount) or less. The total thickness of the tube body 22, the adhesive layer 23, and the oxygen barrier layer 24 is preferably 1.5 mm or more and 60 mm or less, and more preferably 3.5 mm or more and 35 mm or less.
The material of the adhesive layer 23 and the material of the oxygen barrier layer 24 are the same as the material of the oxygen barrier layer 14 and the adhesive layers 33 and 34 of the EF joint 1A of the first embodiment described later.

  The joint main body 2 is a cylindrical member having a receiving port 7 configured so that the above-described resin pipe 5 to be connected can be fitted therein, and is a so-called socket.

  The heating wire 3 is composed of a heating element such as a nichrome wire. The heating wire 3 is spirally and continuously wound along the axial direction of the joint body 2 so as to contact the inner peripheral surface 2a of the joint body 2. The heating wire 3 is wound tightly at one of the receptacles 7, sparsely wound therefrom at a connection portion between the receptacles 7, and wound tightly again at the center of the other receptacle 7. ing.

  The fusion portion M is a portion where the heating wire 3 is wound tightly and can be higher in temperature than the surrounding when the heating wire 3 is energized. That is, when the heating wire 3 wound tightly at the receptacle 7 is energized, the fused portion M is formed.

  On the outer peripheral surface 2 b of the joint body 2, a connector attaching portion 12 for attaching a cable connector of a fusion-attached controller and flowing an electric current to the heating wire 3 is formed. The connector mounting portion 12 is formed with a hollow portion into which a cable connector can be fitted, and is connected to an end of the heating wire 3 (not shown). The connector mounting portion 12 is provided on the outer peripheral surface 2 b of the joint main body 2 provided with the receiving port 7, and protrudes radially outward from the outer peripheral surface 2 b of the joint main body 2.

  Examples of the material of the pipe body 22 and the joint body 2 include polybutene resin, high-density polyethylene resin, medium-density polyethylene resin, and polypropylene resin.

The oxygen barrier layer 14 is embedded in the joint body 2 so as to cover the heating wire 3 from the outer peripheral side of the joint body 2.
In the EF joint 1 </ b> A, as shown in FIG. 1, the oxygen barrier layer 14 is provided in a semicircular shape protruding along the outer periphery of the heating wire 3 toward the outer peripheral side of the joint main body 2.
Further, in the EF joint 1A, the heating wire 3 constitutes a covered heating wire 20 in which the heating wire 3 is covered with the oxygen barrier layer 14 having a semicircular arc shape. The coated heating wire 20 is buried in the joint main body 2 in a state where the plane side faces the inner peripheral side of the joint main body 2.

  Specifically, the heating wire 3 includes a coating layer 32 that covers the heating wire 3 in a semicircular shape that protrudes toward the outer peripheral side of the joint body 2 in the heating wire 3, and an adhesive layer 33 provided on the outer peripheral surface of the coating layer 32. And an oxygen barrier layer 14 provided on the outer peripheral surface of the adhesive layer 33, and an adhesive layer 34 provided on the outer peripheral surface of the oxygen barrier layer 14. That is, the adhesive layer 34 is formed on a portion of the oxygen barrier layer 14 that is in contact with the resin for the main body of the joint main body 2.

  Examples of the material of the oxygen barrier layer 14 include the same materials as those of the oxygen barrier layer 24. Examples of the material for the adhesive layers 33 and 34 include the same materials as those for the adhesive layer 23. In addition, examples of the material of the coating layer 32 include the same materials as the materials of the pipe body 22 and the joint body 2.

Examples of the material of the oxygen barrier layer 14 include polyvinyl alcohol (PVA), ethylene vinyl alcohol copolymer (EVOH), polyvinylidene chloride resin (PVDC), and polyacrylonitrile (PAN).
Further, the thickness of the oxygen barrier layer 14 is preferably 75 μm or more and 200 μm or less, more preferably 100 μm or more and 150 μm or less. When the thickness of the oxygen barrier layer 14 is equal to or more than the above lower limit, the thickness of the oxygen barrier layer 14 can be easily controlled, and the oxygen barrier performance and the gas barrier performance are further enhanced. When the thickness of the oxygen barrier layer 14 is equal to or less than the above upper limit, the amount of the material used is appropriately suppressed, and the material cost is reduced and the weight is reduced.

Examples of the material of the adhesive layers 33 and 34 include a rubber-based hot melt adhesive, modified polyethylene, and modified polypropylene.
Further, the thickness of the adhesive layers 33 and 34 is preferably 50 μm or more and 200 μm or less, and more preferably 75 μm or more and 150 μm or less. When the thickness of the adhesive layers 33 and 34 is equal to or more than the above lower limit, the thickness of the adhesive layers 33 and 34 can be easily controlled, and the adhesiveness between the joint body 2 and the oxygen barrier layer 14 is further enhanced. When the thickness of the adhesive layers 33 and 34 is equal to or less than the above upper limit, the amount of material used is appropriately suppressed, the material cost is reduced, and the weight of the resin tube 5 is reduced.

Next, a method of manufacturing the EF joint 1A according to the first embodiment will be described.
The method of manufacturing the EF joint 1 </ b> A according to the first embodiment includes a resin-made joint body 2 having a plurality of sockets 7, a heating wire 3 buried in a fusion portion 7 </ b> M of the socket 7, and a joint body rather than the heating wire 3. This is a method for manufacturing an EF joint 1 comprising: an oxygen barrier layer 14 provided on the outer peripheral side of a resin tube 2; The manufacturing method of the EF joint 1 </ b> A of the first embodiment is configured such that the coated heating wire 20 coated with the heating wire 3 by the semicircular arc-shaped oxygen barrier layer 14 is placed on the flat side of the coated heating wire 20 in the joint body 2. A step of winding around a core mold (not shown) in a state facing the peripheral side, a step of fitting a mold for resin molding with a gap from the outside around the core mold around which the coated heating wire 20 is wound, and a step of fitting the mold for resin molding. Injecting resin into the mold.

  The coated heating wire formed in a substantially semicircular arc shape in cross section is obtained by laminating the coating layer 32, the adhesive layer 33, the oxygen barrier layer 14, and the adhesive layer 34 on the element wire of the heating wire 3. It can be manufactured by extrusion molding by extruding from an extrusion port having a substantially semicircular cross section.

Next, the coated heating wire 20 covered with the heating wire 3 by the semicircular oxygen barrier layer 14 as described above is wound around the core mold with the flat side of the coated heating wire 20 facing inward ( (See FIG. 1).
Subsequently, a resin molding die (not shown) provided with a gate for injecting the resin for the main body is fitted into a core die (not shown) around which the coated heating wire 20 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 (that is, the EF joint) 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 EF joint 1A.

  According to the EF joint 1 </ b> A of the first embodiment described above, since the oxygen barrier layer 14 is provided on the outer peripheral side from the inner peripheral surface 2 a of the joint main body 2, the oxygen barrier layer 14 extends from the outside to the inside of the hollow portion of the joint main body 2. Oxygen is shut off, so that entry of oxygen into the hollow portion of the joint body 2 can be prevented. Thereby, the oxygen barrier performance can be provided to the EF joint 1. In particular, according to the EF joint 1A, since the oxygen barrier layer 14 is embedded in the resin for the main body constituting the joint main body 2, the oxygen barrier layer 14 is stably disposed, and the oxygen added to the EF joint 1A Barrier performance can be exhibited more stably.

  Further, according to the method of manufacturing the EF joint 1A of the first embodiment, since the oxygen barrier layer 14 is provided in advance on the outer peripheral portion of the heating wire 3 by injection molding, the heating wire 3 is wound around the core mold, and The layer 14 can be efficiently arranged on the outer peripheral side of the heating wire 3, and the oxygen barrier layer 14 can be arranged on the outer peripheral side of the joint body 2 in the heating wire 3 after the subsequent injection molding of the resin for the main body. Therefore, oxygen barrier performance can be provided to the EF joint 1. Thus, the EF joint 1 having the oxygen barrier performance can be efficiently and simply manufactured.

  Further, according to the EF joint 1A and the method of manufacturing the EF joint 1A of the present embodiment, since the adhesive layer 34 is formed at the portion of the oxygen barrier layer 14 in contact with the resin for the main body of the joint main body 2, the oxygen barrier layer 14 And the resin for the main body are more strongly adhered to each other by the adhesive layer 34, so that the oxygen barrier layer 14 can be stably arranged. That is, the oxygen barrier performance of the EF joint 1A can be more stably exhibited.

  Next, an EF joint 1B according to a second embodiment of the present invention will be described. In the components of the EF joint 1B of the second embodiment shown in FIG. 2, the same components as those of the EF joint 1A of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. In FIG. 2, illustration of the resin tube 5 is omitted.

  As shown in FIG. 2, in the EF joint 1 </ b> B of the second embodiment, the oxygen barrier layer 14 is provided on the outer peripheral surface 2 b of the joint main body 2. Specifically, the oxygen barrier layer 14 is disposed so as to cover the outer peripheral surface 2b of the joint main body 2 including the connector mounting portion 12.

Next, a method for manufacturing the EF joint 1B of the second embodiment will be described.
In the method for manufacturing the EF joint 1B according to the second embodiment, first, the wire of the heating wire 3 is wound around a core mold.
Subsequently, a resin mold (not shown) in which a gate for injecting the main body resin is formed is fitted into a core mold (not shown) around which the heating wire 3 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 2.

  In addition to manufacturing the joint body 2 described above, an oxygen barrier resin is injection-molded to form an oxygen barrier layer 14 capable of covering the outer peripheral surface of the joint body 2. The oxygen barrier layer 14 is formed of a resin for molding a resin in which a gate for injecting the oxygen barrier resin is formed in the joint body 2 following the step of completing the joint body 2 by injecting the resin for the body as described above. It can be formed by fitting a mold (not shown) with a gap from the outside and injecting an oxygen barrier resin. As another method, after the step of completing the joint main body 2 or in parallel with the step of completing the joint main body 2, a dedicated resin molding metal having a gate for injecting the oxygen barrier resin is formed. The oxygen barrier layer 14 can be manufactured separately from the joint body 2 by injecting the oxygen barrier resin into a mold (not shown), and the oxygen barrier layer 14 can be covered from the outside of the joint body 2 without gaps.

  According to the EF joint 1B of the second embodiment described above, the main body of the joint main body 2 due to the characteristics of the already manufactured joint main body 2, the resin for the main body, and the resin for the oxygen barrier, the manufacturing reason, and the like. Even if it is difficult to bury the oxygen barrier layer 14 in the resin for use, it is necessary to easily provide the oxygen barrier layer 14 with respect to the joint body 2 and to provide oxygen barrier performance to the entire EF joint 1B. Can be.

  Next, an EF joint 1C according to a third embodiment of the present invention will be described. Note that, in the components of the EF joint 1C of the third embodiment shown in FIG. 3, the same components as those of the EF joint 1A of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. In FIG. 3, illustration of the resin tube 5 is omitted.

  As shown in FIG. 3, in the EF joint 1 </ b> C of the third embodiment, the joint main body 2 has a hollow portion forming the receiving port 7, and is disposed outside the inner portion 2 </ b> I made of resin for the main body. An outer portion 2U made of a resin for the main body. The heating wire 3 and the oxygen barrier layer 14 are provided on the outer peripheral surface of the inner portion 2I of the joint body 2 and on the inner peripheral surface of the outer portion 2U. That is, the oxygen barrier layer 14 is provided between the inner part 2I and the outer part 2U via the adhesive layer 34, respectively.

In the EF joint 1C of the third embodiment, the oxygen barrier layer 14 is an oxygen barrier film 14F having an oxygen barrier performance. The adhesive layer 34 is composed of adhesive films 34I and 34F.
As the material of the oxygen barrier film 14F, the same material as that of the oxygen barrier layer 24 is used. As a material of the adhesive films 34I and 34F, the same material as that of the adhesive layer 23 is used. In particular, in the EF joint 1C of the third embodiment, since the adhesive films 34I and 34F are in contact with the heating wire 3 and the oxygen barrier film 14F is very close to the heating wire 3, the oxygen barrier film 14F and the adhesive film 34I, It is desirable that each material of the 34F does not deteriorate due to heating of the heating wire 3 at the time of heat generation.

Next, a method of manufacturing the EF joint 1C of the third embodiment will be described.
The method for manufacturing the EF joint 1C of the third embodiment includes a step of winding the heating wire 3 around the core mold, and a step of winding the oxygen barrier film 14F forming the oxygen barrier layer 14 so as to cover the whole of the wound heating wire 3. Winding the adhesive film 34F around the outer peripheral surface of the oxygen barrier film 14F, fitting the resin mold to the core mold around which the adhesive film 34F is wound with a gap from the outside, Injecting a resin into the inside.

First, the inner part 2I (so-called preform) of the joint main body 2 is formed by injection molding. Using the inner part 2I as a core mold, the element wire of the heating wire 3 is wound around the outer part of the inner part 2I.
Subsequently, as shown in FIG. 4, an adhesive film 34I for bonding the inner part 2I and the oxygen barrier layer 14 more strongly is wound so as to cover the entire heating wire 3, and the oxygen barrier 34I is placed on the adhesive film 34I. Wind the film 14F.
Subsequently, an adhesive film 34F for stronger bonding between the oxygen barrier layer 14 and the outer portion 2U (so-called outer) of the joint main body 2 is wound on the oxygen barrier film 14F.

Next, a resin molding die (not shown) in which a gate for injecting the resin for the main body is formed in the inner portion 2I around which the heating wire 3, the oxygen barrier film 14F, and the adhesive film 34F are wound, is spaced from the outside. Open and fit.
Subsequently, the resin for the main body is injected into the resin molding die to form the outer portion 2U of the joint main body 2. After the injection molding of the resin for the main body is completed, the resin molding die is removed. Thereafter, the resin for the main body injected into the gate is cut off from the injection molded body to obtain the EF joint 1C.

  According to the EF joint 1C of the third embodiment described above, the oxygen barrier layer 14 is constituted by the oxygen barrier film 14F, so that the oxygen barrier layer 14 can be easily and quickly prepared even for a relatively large joint body 2. To provide an oxygen barrier function to the EF joint 1C.

  Further, according to the method for manufacturing the EF joint 1C of the third embodiment, the oxygen barrier film 14F is efficiently arranged in a simple process via the adhesive film 34I on the outer peripheral side of the inner portion 2I around which the heating wire 3 is wound, By injecting the resin for the main body outside the oxygen barrier film 14F via the adhesive film 34F, the oxygen barrier layer 14 can be embedded in the resin for the main body. Thereby, the oxygen barrier performance can be provided to the EF joint 1C and the oxygen barrier layer 14 can be formed stably.

  Next, an EF joint 1D according to a fourth embodiment of the present invention will be described. In the components of the EF joint 1D of the fourth embodiment shown in FIG. 5, the same components as those of the EF joint 1A of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. In FIG. 5, illustration of the resin tube 5 is omitted.

  As shown in FIG. 5, in the EF joint 1D of the fourth embodiment, the oxygen barrier layer 14 is provided on the outer peripheral surface 2b of the joint main body 2. The oxygen barrier layer 14 is an oxygen barrier film 14F having oxygen barrier performance. An adhesive layer 34 is formed on a portion of the oxygen barrier layer 14 that is in contact with the resin for the main body of the joint main body 2. The adhesive layer 34 is an adhesive film 34F. Specifically, the adhesive layer 34 is provided with an interval along the axial direction of the joint main body 2 in order to make the joint main body 2 and the oxygen barrier layer 14 satisfactorily adhere to each other and to suppress the use amount of the adhesive film 34F. Are arranged.

Next, a method for manufacturing the EF joint 1D of the fourth embodiment will be described.
The method of manufacturing the EF joint 1D of the fourth embodiment includes a step of winding an oxygen barrier film 14F provided with an adhesive layer 34 on the outer peripheral surface 2b (surface) of the joint body 2 provided with the heating wire 3, and Heating the wound joint body 2 from outside.

First, a laminated film (not shown) in which the oxygen barrier film 14F is laminated on the adhesive film 34F is formed.
Subsequently, a resin mold having a gate for injecting the resin for the main body is fitted into the core mold around which the heating wire 3 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 2.

  Next, as shown in FIG. 6, the joint main body 2 around which the oxygen barrier film 14F is wound is heated from the outside to near the softening temperature of the oxygen barrier film 14F and the adhesive film 34F, and the oxygen barrier film is The EF joint 1D is obtained by bringing 14F into close contact with the joint main body 2 without any gap.

  According to the EF joint 1D of the fourth embodiment described above, the same operation and effects as those of the EF joint 1B of the second embodiment and the EF joint 1C of the third embodiment are obtained, and the entire EF joint 1D has an oxygen barrier function. Can be efficiently provided.

Further, according to the method of manufacturing the EF joint 1D of the fourth embodiment, the same functions and effects as those of the method of manufacturing the EF joint 1B of the second embodiment and the EF joint 1C of the third embodiment can be obtained, and as a whole, An EF joint 1C provided with an oxygen barrier function efficiently can be manufactured.
Furthermore, according to the manufacturing method of the EF joint 1D of the fourth embodiment, the oxygen barrier film 14F wound on the surface of the joint main body 2 via the adhesive film 34F is heated from the outside, thereby connecting the oxygen barrier film 14F to the joint. The surface of the main body 2 can be adhered more strongly. Thereby, the oxygen barrier layer 14 of the EF joint 1D can be more stably arranged.

  Next, an EF joint 1E according to a fifth embodiment of the present invention will be described. In the components of the EF joint 1E of the fifth embodiment shown in FIG. 7, the same components as those of the EF joint 1A of the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. In FIG. 7, illustration of the resin tube 5 is omitted.

  As shown in FIG. 7, the EF joint 1E of the fifth embodiment is different from the EF joint 1C of the third embodiment in that the oxygen barrier layer 14 is not formed of the oxygen barrier film 14F but of an oxygen barrier resin. Is omitted. In such a configuration, the oxygen barrier layer 14 is located on the outer peripheral side of the joint body 2 with respect to the heating wire 3.

Next, a method for manufacturing the EF joint 1E according to the fifth embodiment will be described.
The method of manufacturing the EF joint 1E of the fifth embodiment includes a step of winding the heating wire 3 around a core mold, and fitting a resin molding die with a gap from the outside around the core mold around which the heating wire 3 is wound; A step of injecting resin for the main body from the first nozzle 41 into a resin molding die to form the inner resin layer 18I of the joint main body 2; and a step of injecting oxygen from the second nozzle 42 to the outer peripheral side of the inner resin layer 18I. A step of injecting the material of the barrier layer 14 to form the oxygen barrier layer 14 and injecting a resin for the main body from the first nozzle 41 to the outer peripheral surface of the oxygen barrier layer 14 to form the outer peripheral resin layer 18U of the joint main body 2 And Further, the oxygen barrier layer 14 is arranged on the outer peripheral side of the heating wire 3.

More specifically, first, as shown in FIG. 8A, the resin for the main body is injected from the first nozzle 41 to form an inner portion 2I made of the inner peripheral resin layer 18I of the joint main body 2, and the joint main body 2 is formed. The heating wire 3 is wound around the outside of the inner portion 2I of the wire 2.
Subsequently, as shown in FIG. 8B, an oxygen barrier resin is injected from the second nozzle 42 so as to cover the entire inner portion 2I, and the oxygen barrier layer 14 is formed on the inner portion 2I. .

Next, a resin molding die having a gate for injecting the resin for the main body is fitted into the inner portion 2I where the oxygen barrier layer 14 is formed with a gap (cavity) from the outside.
Subsequently, the relative position of the first nozzle 41 is moved in accordance with the arrangement of the resin molding die, and the resin for the main body is injected into the inside of the resin molding die, and the outer peripheral resin layer 18U of the joint main body 2 is formed. The outer part 2U is formed. After the injection molding of the resin for the main body is completed, the resin molding die is removed. Thereafter, the resin for the main body injected into the gate is cut off from the injection molded body to obtain the EF joint 1E.
8A to 8C, illustration of the heating wire 3 is omitted.

  According to the EF joint 1E of the fifth embodiment described above, the same operation and effect as those of the EF joint 1C of the third embodiment can be obtained, and the oxygen barrier function can be efficiently provided to the EF joint 1E.

Further, according to the method of manufacturing the EF joint 1E of the fifth embodiment, the same operation and effect as those of the method of manufacturing the EF joint 1C of the third embodiment can be obtained, and the EF joint 1E provided with the oxygen barrier function efficiently can be obtained. Can be manufactured.
Further, according to the method of manufacturing the EF joint 1E of the fifth embodiment, the joint main body 2 and the oxygen barrier layer 14 are sequentially formed from the molding stage using the first nozzle 41 and the second nozzle 42, and the first nozzle 41 and the second nozzle 42 are formed in parallel. Because they are integrated, the EF joint 1E can be provided with oxygen barrier performance and the oxygen barrier layer 14 can be formed more stably.
When forming the outer portion 2U, instead of moving the relative position of the first nozzle 41 in accordance with the arrangement of the resin molding die, a second nozzle 41 previously arranged in accordance with the arrangement of the resin molding die is used. The resin for the main body may be injection-molded from the third nozzle using three nozzles (first nozzle).

Further, as a modified example of the fifth embodiment, the same nozzle may be used as the nozzle for injecting the resin, and the inner resin layer 18I, the oxygen barrier layer 14, and the outer resin layer 18U may be formed. In this case, the nozzle 41 is inserted into the mold at a position (mainly on the side opposite to the gate) where the resin merges (weld) in the mold and outside the gap (cavity) forming the joint body. There is provided a space for forming a resin escape portion formed by flowing the injected resin.
More specifically, a smaller amount of resin for the main body than the volume of the gap (cavity) provided in the mold is injected from the nozzle into the mold (short shot injection). Next, the oxygen-barrier resin is injected from the same nozzle 41, and the pressure is further increased so that the main-body resin is washed away with the oxygen-barrier resin. As a result, the resin for the main body can spread the resin for the main body to every corner inside the gap in the mold, and the resin for the oxygen barrier penetrates into the inside of the main body resin, whereby the oxygen barrier layer 14 is formed. . After injecting a sufficient amount of the oxygen barrier resin, the body resin constituting the periphery of the nozzle 14 is injected, and the oxygen barrier resin in the nozzle 14 is pushed into the gap of the mold.
At this time, a space for forming a resin escape portion formed by allowing the resin for the main body to escape from the gap in the mold to the outside of the joint body is provided outside the gap forming the joint body in the mold. I do. The space for forming the resin escape portion and the gap for forming the joint main body are connected by a runner provided at a position where the resin injected in the mold becomes a junction (weld) where the injected resin joins. ing. Then, at the time of injection molding, the resin escape portion is formed integrally with the joint body by releasing at least the body resin from the junction where the resin for the body injected from the nozzle 41 joins or the vicinity thereof to the external resin escape portion. You. The resin escape portion is cut out together with the gate from the joint body, and remains on the joint body as a gate cut mark and a resin escape mark.
As a result, the flow of the resin for the main body stops at the junction and does not solidify as it is, and the resin for the main body is pushed toward the resin escape portion by the oxygen barrier resin, so that the Can be inserted, and the EF joint 1E in which the oxygen barrier layer 14 is formed without a break in the circumferential direction of the joint main body can be manufactured.

  As described above, the preferred embodiments of the present invention have been described in detail. However, the present invention is not limited to the specific embodiments, and various modifications may be made within the scope of the present invention described in the appended claims. Deformation and modification are possible.

For example, as a modified example of the EF joint 1C of the third embodiment described above, an EF joint 1G shown in FIG. 9 is given. The EF joint 1G is obtained by omitting the inner part 2I of the joint main body 2 and the adhesive film 34I in the EF joint 1C. That is, in the EF joint 1G, the heating wire 3 and the oxygen barrier layer 14 are provided on the inner peripheral surface of the outer portion 2U of the joint main body 2.
When manufacturing the EF joint 1G, first, the element wire of the heating wire 3 is wound around a core mold, and the oxygen barrier film 14F is wound so as to cover the entire heating wire 3. Thereafter, in the method of manufacturing the EF joint 1C, the same operation as in the step of injection molding the resin for the main body into the inner portion 2I may be performed.

  Further, the configurations of the above-described embodiments may be appropriately combined.

1, 1A EF joint (electric fusion joint), 2 joint body, 2b outer peripheral surface, 3 heating wire, 7 receptacle, 14 oxygen barrier layer, 14F oxygen barrier film, 18I inner resin layer , 18U: outer peripheral resin layer, 20: coated heating wire, 34: adhesive layer, 34F: adhesive film, 41: first nozzle, 42: second nozzle

Claims (2)

An electric fusion joint that connects a plurality of resin tubes by fusing by heating,
A resin joint body having a plurality of sockets,
A heating wire embedded in the fused portion of the receptacle,
An oxygen barrier layer provided on the outer peripheral side of the joint main body with respect to the heating wire,
Equipped with a,
The oxygen barrier layer is embedded in the joint body so as to cover the heating wire from an outer peripheral side of the joint body,
The oxygen barrier layer is that provided in a semicircular shape which is convex to the outer peripheral side of the joint body along the outer periphery of the heating wire,
Electric fusion joint. A resin-made joint body having a plurality of sockets, a heating wire embedded in the fusion portion of the socket, and an oxygen barrier layer provided on the outer peripheral side of the joint body with respect to the heating wire, A method for manufacturing an electric fusion joint, which is connected by inserting a resin tube into a receiving port and fusing by heating,
The coated heating wire coated with the heating wire by the oxygen barrier layer having a plane along the inner peripheral surface of the joint main body and a semicircular curved surface convex from the plane to the outer peripheral side of the joint main body , a step of winding the core mold in a state where the flat surface of the coated heating wire toward the inner periphery of the joint body,
A step of fitting a resin molding mold with a gap from the outside in the core mold around which the coated heating wire is wound,
A step of injecting a resin into the resin molding die,
And having a
A method for manufacturing an electric fusion joint.

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