JP2881404B2 - Method of joining synthetic resin products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for joining synthetic resin products.

[0002]

2. Description of the Related Art Conventionally, there has been a joining method of a synthetic resin product in which an electric wire is arranged on a joint surface of a synthetic resin product, and the electric wire is energized to heat and melt the synthetic resin to be joined. However, the cross-linked synthetic resin has a large molecular weight and a portion having a three-dimensional structure, and the ultra-high molecular weight synthetic resin has an extremely large molecular weight. It was difficult to perform fusion with the required strength. Therefore, in order to fuse a synthetic resin which is difficult to be fused as described above (hereinafter referred to as a hardly fusible synthetic resin), a two-layer synthetic resin which is relatively easily fusible with a hardly fusible synthetic resin is used. A technique of forming and fusing a structure, and a technique of oxidizing and fusing the surface of a non-fusible synthetic resin are already known.

[0003]

However, in the former technique, a special mold is used at the time of manufacturing, so that the cost of the mold is increased, and the molding speed and molding temperature must be strictly controlled. The production efficiency is limited and the production cost is high, and the mechanical strength and chemical resistance, heat resistance, and weather resistance of the product are reduced. In order to oxidize the surface, a high voltage, ultraviolet rays, an oxidizing agent, and the like are required, which has the same problem as the former technique.

[0004]

SUMMARY OF THE INVENTION According to the present invention, there is provided a synthetic resin, in which a synthetic resin product made of a non-fusible synthetic resin is joined by fusion without causing the above-mentioned problems.
At the joint surface of the electrofusion joint that joins the tubes
A helical tubular electric wire is buried, and the electric wire is insulated outside the conductor.
The synthetic resin film is coated via the edge layer and the synthetic resin
The coating is made of a synthetic resin containing unsaturated bonds in air or oxygen.
It is heated and oxidized to contain peroxide, and
In both cases, the synthetic resin film is heated and melted to the set temperature and melted.
It is the one that has been bonded .

[0005]

[Action] When a synthetic resin to be bonded and a synthetic resin containing peroxide that are difficult to be fused are heated and melted, the peroxide is decomposed to generate radicals, and hydrogen of the synthetic resin to be bonded is removed. By reducing the drawing and the molecular weight, the difficulty in fusibility is reduced, the fusibility is exhibited, and fusion can be performed. In addition, since the molten resins can be chemically bonded to each other, strong fusion can be performed. Furthermore, by making the synthetic resin for fusion a resin containing an unsaturated bond, the unsaturated groups are polymerized to form a crosslinked resin, so that a stronger fusion can be achieved.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to an embodiment shown in the drawings. FIG. 1 shows an example of a synthetic resin tube (1) made of cross-linked polyethylene or ultra-high molecular synthetic resin joined by the method of the present invention and a joint thereof (2). Fusion joints are used.

The electrofusion joint (2) has an electric wire (3) embedded therein, and is energized through the electric wire (3) to form a resin on the joint surface between the outer surface of the pipe (1) and the inner surface of the joint (2). (Hereinafter referred to as a synthetic resin to be joined) is heated and melted, and the pipe (1) and the joint (2) are fused. As shown in FIG. 1A, an electric wire (3) used for the joint (2) is provided with an insulating layer (3b) made of a glass fiber braid or the like around a conductive (3a) such as a nickel wire. A single wire (3) coated with a synthetic resin film (3c) is folded back at the intermediate portion and doubled, and spirally wound, partially as shown in FIG. This electric wire (3) is formed by welding (4) and keeping the shape of a cylinder, and connecting terminals (5) to both ends of a conductive (3a) drawn in the same direction.
Is inserted into a molding die and the joint (2) is injection-molded, whereby the electrofusion joint (2) can be manufactured. A connection terminal (5) is provided by a controller which is connected to the joint (3) at the time of fusion.
By heating and melting the wire covering resin together with the synthetic resin to be joined to the set temperature based on the heat pattern according to the product type, maintaining the temperature at that temperature for a predetermined time, cutting off the current and cooling After that, fusion is performed.

[0008] When the pipe (1) and the joint (2) are made of a non-fusible resin such as a cross-linked resin or an ultra-high polymer resin, fusion is difficult.

Therefore, in the present embodiment, a peroxide is contained in the resin between the joining synthetic resins, that is, the electric wire coating resin which is a synthetic resin for fusion, and a chemical reaction is caused at the time of fusion using the coating resin. In this way, fusion is performed.

The resin for covering electric wires is a resin containing an unsaturated bond, particularly a double bond, a double bond having an allylic position, an acryl group or a methacryl group, for example, butadiene resin, styrene butadiene rubber, butadiene rubber, isoprene rubber, EP
M, EPDM, nitrile butadiene rubber, chloroprene rubber, butyl rubber, polyethylene rubber, polyisobutylene, cumarone resin, unsaturated polyester resin, furan resin, petroleum resin, cyclopentadiene petroleum resin, polyhydroxy polyolefin, maleic acid resin, fumaric acid resin By heating and melting and stirring polyalcohol methacrylate and the like in the air or oxygen, peroxides such as peroxides and hydroperoxides are generated in the resin. The required amount of peroxide in the resin,
When a peroxide such as hydroperoxide is already contained, heating and melting stirring in air or oxygen need not be performed. If necessary, ultraviolet rays may be irradiated, or peroxides such as peroxides and hydroperoxides may be added.

The unsaturated group may be in the main chain or side chain of the resin, or a compound containing an unsaturated group in the resin, for example, oleic ester, stearic ester, lauric ester, polyethylene glycol acryl. An acid diester monomer or the like may be mixed.

In order to stabilize the hydroperoxide ion, trialkylamine, methacrylic acid and its metal salt, especially a nickel complex, 2-methacryloyloxyethyl acid phosphate and its metal salt, especially a nickel complex, di-2-amine Methacryloyloxyethyl acid phosphate and a metal salt thereof, particularly a nickel complex, may be contained.

As described above, a synthetic resin containing an unsaturated bond is heated and oxidized in air or oxygen to produce an electric wire covering resin containing a peroxide. The electric wire (3) can be manufactured by covering the insulating layer (3b) with the extruder.

At the time of fusion of the pipe (1) and the joint (2), the conductor (3a) of the electric wire (3) is connected to the pipe (2) by the controller.
The resin is heated to 00 to 250 ° C. and held at that temperature for several tens of seconds to heat and melt the resin around the conductor (3a), that is, the electric wire coating resin and the synthetic resin to be joined. At this time, the peroxide and the unsaturated bond in the wire coating resin are radically cleaved to form a chemical bond with the synthetic resin to be joined by a radical reaction such as a hydrogen abstraction reaction and a recombination reaction. Next, the controller sets the conductor (3a) of the electric wire (3) to 300 to 350 ° C.
The temperature is raised to a certain temperature and maintained at that temperature for several tens of seconds to polymerize unsaturated bonds in the molten resin and cause a cross-linking reaction, thereby performing fusion and obtaining high fusion strength.

Fusion can be performed only by a chemical reaction with the synthetic resin which is difficult to fuse due to a peroxide in the wire coating resin. However, by adding an unsaturated bond to the wire coating resin, the peroxide is oxidized. Easy to produce the product, stably perform the chemical bonding at the time of fusion, and also increase the fusion strength by causing the cross-linking reaction. And effective.

Further, when the wire coating resin itself is oxidized (peroxide containing operation), the peroxide is contained in the resin, so that the amount of the peroxide increases, and the chemical bonding with the bonding synthetic resin becomes impossible. Chemical reaction (radical reaction, hydrogen abstraction reaction, polymerization reaction, recombination reaction, etc.) easily occurs, and stronger fusion can be obtained. However, the above effects cannot be expected by oxidizing only the wire coating resin surface, In manufacturing, when the wire coating resin itself is oxidized, it can be mass-produced at once, but when oxidizing the resin surface, mass production is very difficult. It is effective to include the substance in the resin.

In addition, since the resin and the peroxide are chemically bonded at the time of fusion, no by-products are produced outside, or only water is used when the peroxide is hydroperoxide. Since it does not come out, there is no odor and there is no need to pay attention to the effects of by-products on the human body.

The embodiments of the present invention have been described above.
The present invention is not limited to these examples, but may be provided with the structural requirements, achieve the object of the present invention, and be appropriately modified and implemented within a range having the following effects. is there.

[0019]

As described above, according to the present invention, the synthetic resin to be joined of the synthetic resin product is heated and melted, and at the same time, the resin is hardly fused and the resins are chemically bonded to each other to form a joint. Therefore, it is possible to join by fusion even with synthetic resin products made of hard-to-fuse resin, without decreasing the mechanical strength and chemical resistance, heat resistance, weather resistance, etc. of the product at that time,
It has a remarkable effect that the production cost of the product hardly increases.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a synthetic resin product joined by the method of the present invention.

[Explanation of symbols]

 (1) (2) Synthetic resin products

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-64-80517 (JP, A) JP-A-1-295829 (JP, A) JP-B-60-5166 (JP, B2) (58) Field (Int.Cl. ⁶ , DB name) B29C 65/02-65/36 C08J 5/12 C09J 5/06

Claims (1)

(57) [Claims] 1. An elect for joining a synthetic resin pipe (1).
Spiral cylindrical electric wire on the joint surface of Rofusion joint (2)
(3) is buried, and the electric wire (3) is out of the conductive (3a).
Side is covered with a synthetic resin film (3c) via an insulating layer (3b)
At the same time, the synthetic resin film (3c) contains unsaturated bonds.
Peroxidation by heating and oxidizing synthetic resin in air or oxygen
Material and a synthetic resin film (3
A method of joining synthetic resin products, wherein c) is heated and melted to a set temperature to perform fusion joining .