JP2868092B2 - Electrofusion fittings - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrofusion joint for joining a member to be joined such as a polyolefin pipe, particularly a conduit for hot water to a side surface of another conduit.

[Conventional technology]

A crosslinked polyolefin pipe such as silane crosslinked polyethylene is used as a conduit for hot water. This crosslinked polyolefin is excellent in high-temperature performance such as heat resistance and high-temperature creep properties, and has shape retention performance, but unlike a non-crosslinked polyolefin, it cannot be fused to an object to be joined. Therefore, an electrofusion joint used as a joint of a non-crosslinked polyolefin pipe cannot be used as a joint of a crosslinked polyolefin pipe. Also, an electrofusion joint cannot be formed using a crosslinked polyolefin.

Therefore, as a joint for joining a crosslinked polyolefin pipe or a joint using a crosslinked polyolefin, a joint for performing mechanical joining is used. However, in the case of hot water pipes, the working pressure is high and the strength is required, which complicates the structure, and the workability of the piping is poor,
Since the sealing is performed by compression, there is a problem that long-term performance degradation occurs, such as degradation of sealing performance due to creep of the pipe.

[Problems to be Solved by the Invention] In order to solve the above problems, the present invention increases the heat resistance by using a crosslinked thermoplastic resin, and enhances the sealing performance by fusion, and can be optionally connected to the side surface of the conduit. Another object of the present invention is to provide an electrofusion joint having good workability.

[Means for solving the problem]

 The present invention is the following electrofusion joint.

(1) A joint for connecting an object to be joined whose surface layer or the entirety is made of a thermoplastic resin, wherein a tubular second joint is integrally provided on the top of the clasp-shaped first joint. In the electrofusion joint, the clad-shaped crosslinked thermoplastic resin layer forming the first joint portion, and the clad-shaped crosslinked thermoplastic resin at a position in contact with the object to be bonded inside the clad-shaped crosslinked thermoplastic resin layer A non-crosslinked thermoplastic resin layer formed integrally with the layer; a heating wire provided on the inner, outer, or inner surface of the non-crosslinked thermoplastic resin layer; and a tubular wire forming a second joint. A cross-linked thermoplastic resin layer, comprising a connecting member integrally fixed to the tubular cross-linked thermoplastic resin layer, wherein the cross-shaped cross-linked thermoplastic resin layer is on both end sides of the non-cross-linked thermoplastic resin layer, The non-crosslinked thermoplastic resin layer is exposed at the end Internal has a object to be bonded proximity portions formed so as to prevent the connecting member is secured to the crosslinked thermoplastic resin layer of the tubular to be integrated in the saddle-shaped crosslinked thermoplastic resin layer,
After the cross-linkable thermoplastic resin is injected and laminated and integrated with the non-cross-linked thermoplastic resin layer with the heating wire disposed on the outer surface or inner surface, the cross-linkable thermoplastic resin layer An electrofusion joint fixed to the clad-shaped crosslinked thermoplastic resin layer by cross-linking to form a clad and tubular crosslinked thermoplastic resin layer.

(2) A joint for connecting an object to be joined whose surface layer or the entirety is made of a thermoplastic resin, wherein a tubular second joint is integrally provided on the top of the clam-like first joint. In the electrofusion joint, a clad-shaped crosslinked thermoplastic resin layer for joining the first joint portion, and a clad-shaped crosslinked thermoplastic resin at a position in contact with an object to be bonded inside the clad-shaped crosslinked thermoplastic resin layer A non-crosslinked thermoplastic resin layer formed integrally with the layer; a heating wire provided on the inner, outer, or inner surface of the non-crosslinked thermoplastic resin layer; and a tubular wire forming a second joint. A cross-linked thermoplastic resin layer, and a non-cross-linked thermoplastic resin layer integrally laminated on an outer peripheral portion of the tubular cross-linked thermoplastic resin layer, wherein the cross-shaped cross-linked thermoplastic resin layer is a non-cross-linked thermoplastic resin. Non-crosslinked thermoplastic resin layer on both sides of the layer A non-crosslinked thermoplastic resin layer laminated on the tubular crosslinked thermoplastic resin layer has a joined body adjacent portion formed so as to prevent exposure to the end side, Injection of the crosslinkable thermoplastic resin in a state where it is placed in the injection mold together with the non-crosslinked thermoplastic resin layer in which the heating wire is arranged on the inner, outer surface, or inner surface integrated with the resin layer, and laminated and integrated After that, the electrofusion joint is fixed to the cross-linked thermoplastic resin layer by cross-linking the cross-linkable thermoplastic resin layer to form the cross-linked thermoplastic thermoplastic resin layer.

In the present invention, the clad-shaped crosslinked thermoplastic resin layer and the tubular crosslinked thermoplastic resin layer are formed integrally, and the crosslinked thermoplastic resin layer thus integrated and the non-crosslinked thermoplastic resin are adjacent to each other. And integrated. Since the crosslinked thermoplastic resin does not have fusibility, even if the crosslinked thermoplastic resin and the non-crosslinked thermoplastic resin after crosslinking are molded by injection molding or the like, the respective layers are not separated and integrated, but are not crosslinked. When the crosslinkable thermoplastic resin and the non-crosslinkable thermoplastic resin are heat molded and integrated, and then the crosslinkable thermoplastic resin is crosslinked, a laminate in which the crosslinkable thermoplastic resin and the non-crosslinkable thermoplastic resin are integrated is obtained. Can be In the present invention, a laminate in which the crosslinked thermoplastic resin layer and the non-crosslinked thermoplastic resin layer are integrated as described above is used. The clad-shaped crosslinked thermoplastic resin layer has portions to be joined near both ends of the non-crosslinked thermoplastic resin layer, and prevents the non-crosslinked thermoplastic resin layer from being exposed to the end.

The crosslinked thermoplastic resin has a three-dimensional structure due to intermolecular crosslinking of the thermoplastic resin, and in addition to those crosslinked with a crosslinking agent such as a silane crosslinked thermoplastic resin, a divinylbenzene crosslinked thermoplastic resin, an organic peroxide, Those directly crosslinked by radiation or the like may be used.

Non-crosslinked polyolefin is a non-crosslinkable thermoplastic resin generally used as a thermoplastic resin.

Specific examples of the thermoplastic resin according to the present invention include polyolefin. Examples of the polyolefin include homo- or copolymers of α-olefins having 2 to 20 carbon atoms, preferably 2 to 12 carbon atoms. Preferred α-olefins include ethylene, propylene, butene-1,4-methylpentene-1 and the like.

The second joint is formed by integrally connecting or laminating a connecting member or a non-crosslinked thermoplastic resin layer to a tubular crosslinked thermoplastic resin layer. As such a second joint,
A member to which another connecting member such as a mounting bracket is attached, or a member having a double structure of a crosslinked thermoplastic resin layer and a non-crosslinked thermoplastic resin layer and joined by another electrofusion joint can be adopted.

(Operation)

The electrofusion joint of the present invention is arranged in a mold with a heating wire embedded in the inner, outer surface, or inner surface of the jelly-shaped non-crosslinked thermoplastic resin layer, and is integrated with the second joint. After placing the tubular connecting member or non-crosslinked thermoplastic resin layer in the mold, injecting the crosslinkable thermoplastic resin layer and laminating and integrating it, the crosslinkable thermoplastic resin is crosslinked and crosslinked. By forming a first joint as a thermoplastic resin layer and integrally forming a second joint on the top of the spine-shaped crosslinked thermoplastic resin layer of the first joint, a crosslinked thermoplastic resin is formed. It is manufactured by integrally fixing the resin layer and the connection member or the non-crosslinked thermoplastic resin layer.

The electrofusion joint thus manufactured is
A first bonding portion is attached to a side surface of a member to be bonded such as a tube having a thermoplastic resin layer such that the non-crosslinking thermoplastic resin layer is in contact with the member to be bonded. Melts and is integrally fused to the joined body.

Then, when the connection terminal of another object is joined to the second joint formed on the top of the first joint using a connecting member or a non-crosslinked thermoplastic resin layer, Any other object can be connected to any side. In this case, since the cross-linked thermoplastic resin layer has the parts to be joined near both ends of the non-crosslinked thermoplastic resin layer, the non-crosslinked thermoplastic resin layer is not exposed to the end side, and therefore, is not crosslinked. When the thermoplastic resin layer is softened, it is prevented from flowing out of the end portion and lowering the sealing property.

The object to be joined is preferably one whose surface layer or the whole is made of a thermoplastic resin, particularly a resin having compatibility, and one made of a non-crosslinked thermoplastic resin shows particularly excellent fusion bonding properties.

The second joint having the connection member is obtained by disposing the connection member in a molding die and integrally forming the second joint with the non-crosslinked thermoplastic resin layer. At this time, when the embedded portion of the connection member is coated with an adhesive material such as a modified thermoplastic resin and molded, a second joint portion in which the connection member is firmly adhered is obtained. The second joint is connected to a connection terminal of another object using a mechanical joint such as a screw or a coupler.

Furthermore, when the non-crosslinked thermoplastic resin layer is integrally formed on the outer periphery of the crosslinked thermoplastic resin layer as described above, the non-crosslinked thermoplastic resin layer having a fusible property is formed on the outer periphery. Is obtained. The second joint portion can be connected by another electrofusion joint that abuts a connection terminal of another object to be joined and covers the vicinity thereof over the entire periphery.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a front view of an electrofusion joint of a reference example, FIG. 2 is a sectional view taken along line AA of FIG. 2, FIG.
The figure is a sectional view taken along the line BB of FIG. 2 showing the joined state.
In the figure, reference numeral 1 denotes an electrofusion joint, in which a first joint 1a having a hollow shape is formed at one end, and a tubular second joint 1b is integrally formed at the center of the top. The first joining portion 1a is formed integrally with the crosslinked polyolefin layer 3 at a position in contact with the to-be-joined body 4 inside the crosslinked polyolefin layer 3 having the opening 2 at the center and the inside of the crosslinked polyolefin layer 3. It has a clad-shaped non-crosslinked polyolefin layer 5 and a heating wire 6 provided inside the clad-shaped non-crosslinked polyolefin layer 5.

The second joint portion 1b is formed of a tubular crosslinked polyolefin layer 3a formed integrally with the crosslinked polyolefin layer 3 and a crosslinked polyolefin layer 3a at a position inside the crosslinked polyolefin layer 3a which is in contact with the object 4a. It has a tubular non-crosslinked polyolefin layer 5a formed as desired, and a heating wire 6a provided in the non-crosslinked polyolefin layer 5a. The non-crosslinked polyolefin layers 5, 5a of the crosslinked polyolefin layers 3, 3a are provided at both ends of the non-crosslinked polyolefin layers 5, 5a.
3b is formed, thereby preventing the non-crosslinked polyolefin layers 5, 5a from being exposed to the end.

The members to be joined 4 and 4a are formed of a tube having a thermoplastic resin layer such as polyethylene, and may be entirely formed of a fusible thermoplastic resin. Coated with a fusible thermoplastic resin. The article 4 has a bypass port 7 at a position corresponding to the opening 2 on the side surface.

The electrofusion joint 1 is inserted into a mold with the heating wires 6, 6a embedded in the non-cross-linked polyolefin layers 5, 5a, and the cross-linkable polyolefin containing a cross-linking agent, a cross-linking assistant, a catalyst, etc. in the polyolefin. And then laminating and integrating, and then cross-linking the cross-linkable polyolefin layer to form cross-linked polyolefin layers 3 and 3a.

Electrofusion joint 1 thus manufactured
In order to make the opening 2 of the first joint portion 1a coincide with the bypass port 7 formed on the side surface of the joined object 4 such as a polyolefin tube, the clad-shaped non-crosslinked polyolefin layer 5 is formed on the side surface of the joined object 4. When the heating wire 6 is energized, the non-crosslinked polyolefin layer 5 is melted and fused to the object 4 to be integrated.

The end of the object 4a to be joined is inserted into the second joining portion 1b and brought into contact with the non-cross-linked polyolefin layer 5a. When the heating wire 6a is energized, the non-cross-linked polyolefin layer 5a is fused to be joined. It is integrated with the joined body 4a. As a result, the joined bodies 4 and 4a are connected via the bypass port 7 and the opening 2. In this case, the crosslinked polyolefin layers 3 and 3a are non-crosslinked polyolefin layers.
Since the non-crosslinked thermoplastic resin layers 5 and 5a are not exposed to the end side because the joined body adjacent portions 3b are provided at both end sides of 5a, when the noncrosslinked thermoplastic resin layers 5 and 5a are softened, It is prevented from flowing out from the end portion and deteriorating the sealing performance.

Since the crosslinked polyolefin layer 3 forming the joint body bears the heat resistance, the electrofusion joint 1 is excellent in shape retention even when used for joining a hot water supply pipe or the like.
On the other hand, in a state where the non-crosslinked polyolefin layers 5 and 5a are integrated with the crosslinked polyolefin layers 3 and 3a, they are fused and integrated with the bonded objects 4 and 4a. The sealability is maintained over the entire length.

FIG. 5 and FIG. 6 show another embodiment.
It is B sectional drawing equivalent. In any case, the electrofusion joint 1 has a first joint portion 1a configured in the same manner as in FIGS.

In the embodiment shown in FIG. 5, the second joining portion 1b is configured such that the insertion portion 8a of the connecting member 8 is provided with an adhesive layer 9 such as a modified polyolefin layer on a tubular crosslinked polyolefin layer 3a formed integrally with the crosslinked polyolefin layer 3. Is fixed through. The connecting member 8 is formed of a metal pipe, and a joining portion 10 such as a screw portion for joining to the joined object 4a is formed on a protruding portion 8b, and a hexagonal spanner hook 11 is formed on an intermediate portion. I have.

The above-mentioned electrofusion joint 1 has a connecting member 8.
And the first joint portion 1a is formed in the same manner as described above. The second joining portion 1b is joined to the joined object 4a by the joining means 10. As the connecting member 8, a member having another joining means 10, such as a socket having an internal thread, can be used.

In the embodiment shown in FIG. 6, in the second joint portion 1b, a tubular non-crosslinked polyolefin layer 5b is laminated and integrated around the outer periphery of a tubular crosslinked polyolefin layer 3a formed integrally with the crosslinked polyolefin layer 3.

The above-mentioned electrofusion joint 1 is manufactured in the same manner as described above by integrally laminating the non-crosslinked polyolefin layer 5b during molding. The second joint 1b is connected to the object 4a
Can be connected using other electrofusion joints, or can be directly connected to a joined object having an electrofusion joint structure.

In the above description, as the second joint 1b,
The structure is not limited to the one shown in the figure, and may have another structure.
The heating wires 6, 6a may be provided on the outer surface or the inner surface of the non-crosslinked polyolefin layers 5, 5a.

〔The invention's effect〕

According to the present invention, a connecting member or a non-crosslinked thermoplastic resin layer is fixed or laminated on a tubular crosslinked thermoplastic resin layer formed integrally with a clad crosslinked thermoplastic resin layer, and the clad crosslinked thermoplastic resin is formed. Heating wires are provided on the inside, outer surface or inner surface of the non-crosslinked thermoplastic resin layer integrated with the layer, so that other objects can be fused to the side surface of the object, and high-temperature performance such as heat resistance and An electrofusion joint having excellent sealing properties and excellent workability such as mounting work can be obtained.
In addition, since the cross-linked thermoplastic resin layer has portions to be joined at both end sides of the non-crosslinked thermoplastic resin layer, the non-crosslinked thermoplastic resin layer is not exposed to the end side, and therefore the non-crosslinked thermoplastic resin layer is not exposed. When the plastic resin layer is softened, it is prevented from flowing out of the end portion and lowering the sealing property.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view showing an electrofusion joint of a reference example, FIG. 2 is a sectional view taken along line AA of FIG. 2, FIG. 3 is a bottom view, and FIG. FIG. 5 is a sectional view taken along the line BB of FIG. 2 showing another embodiment. In each figure, the same reference numerals indicate the same or corresponding parts, 1 is an electrofusion joint, 1a is a first joint, 1b is a second joint, 2 is an opening, 3, 3a is a crosslinked polyolefin layer, 4, Reference numeral 4a denotes an object to be bonded, 5 and 5a denote non-crosslinked polyolefin layers, 6 and 6a denote heating wires, 7 denotes a bypass port, and 8 denotes a connection member.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroyuki Nishimura 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi, Osaka Inside Osaka Gas Co., Ltd. (72) Inventor Akio Nakashiba 4 Hirano-cho, Chuo-ku, Osaka-shi, Osaka 1-2 1-2, Osaka Gas Co., Ltd. (72) Inventor Fumio Hase 6-1-2, Waki-machi, Waka-cho, Kuga-gun, Yamaguchi Prefecture Inside Mitsui Petrochemical Industry Co., Ltd. 6-1-2 Kimachi Waki Mitsui Petrochemical Industry Co., Ltd. (72) Inventor Toshio Shibuchi 2-10-16 Minamikagaya, Suminoe-ku, Osaka-shi, Osaka Shinwa Sangyo Co., Ltd. (72) Inventor Nakaoka Mikio 2-10-16 Minamikagaya, Suminoe-ku, Osaka City, Osaka Prefecture Inside Shinwa Sangyo Co., Ltd. (56) References JP-A-63-254296 (JP, A) French Patent Publication 2606487 (FR, 1)

Claims (2)

(57) [Claims] 1. A joint for connecting an object to be joined whose surface layer or the whole is made of a thermoplastic resin, wherein a tubular second joint is integrally provided on the top of the first joint of the shape of a clam. In the obtained electrofusion joint, the clad-shaped crosslinked thermoplastic resin layer forming the first joint portion and the clad-shaped crosslinked thermoplastic resin are provided at a position in contact with the object to be bonded inside the clad-shaped crosslinked thermoplastic resin layer. A non-crosslinked thermoplastic resin layer formed integrally with the thermoplastic resin layer; a heating wire provided on the inside, outer surface, or inner surface of the non-crosslinked thermoplastic resin layer; A tubular cross-linked thermoplastic resin layer, and a connecting member integrally fixed to the tubular cross-linked thermoplastic resin layer, wherein the cross-shaped cross-linked thermoplastic resin layer is on both ends of a non-cross-linked thermoplastic resin layer. The non-crosslinked thermoplastic resin layer is exposed at the end Has a object to be bonded proximity portions formed so as to prevent the that, the connecting member being secured to the crosslinked thermoplastic resin layer of the tubular inner integral to the saddle-shaped crosslinked thermoplastic resin layer,
After the cross-linkable thermoplastic resin is injected and laminated and integrated with the non-cross-linked thermoplastic resin layer with the heating wire disposed on the outer surface or inner surface, the cross-linkable thermoplastic resin layer An electrofusion joint fixed to the clad-shaped crosslinked thermoplastic resin layer by cross-linking to form a clad and tubular crosslinked thermoplastic resin layer. 2. A joint for connecting an object to be joined whose surface layer or the whole is made of a thermoplastic resin, wherein a tubular second joint is integrally provided on the top of the first joint of the claws. In the obtained electrofusion joint, a clad-shaped crosslinked thermoplastic resin layer for joining the first joint portion, and a clad-shaped crosslinked thermoplastic resin layer at a position in contact with the object to be bonded inside the clad-shaped crosslinked thermoplastic resin layer. A non-crosslinked thermoplastic resin layer formed integrally with the thermoplastic resin layer; a heating wire provided on the inside, outer surface, or inner surface of the non-crosslinked thermoplastic resin layer; A tubular cross-linked thermoplastic resin layer; and a non-cross-linked thermoplastic resin layer integrally laminated on an outer peripheral portion of the tubular cross-linked thermoplastic resin layer. Non-crosslinked thermoplastic on both ends of the plastic resin layer A non-crosslinked thermoplastic resin layer laminated to the tubular crosslinked thermoplastic resin layer has a joined body adjacent portion formed so as to prevent the oil layer from being exposed to the end side, Injecting the crosslinkable thermoplastic resin in a state where it is arranged in the injection molding die together with the non-crosslinking thermoplastic resin layer in which the heating wire is arranged on the inside, the outer surface, or the inner surface integrated with the crosslinked thermoplastic resin layer An electrofusion joint fixed to the cross-linked thermoplastic resin layer by laminating and integrating the cross-linkable thermoplastic resin layer to form a clad and tubular cross-linked thermoplastic resin layer.