JPH0911332A - How to connect pipes - Google Patents

Abstract

(57) Abstract: When a pipe made of a thermoplastic resin is connected, it is provided in contact with the outer surface of the pipe 1 at the connecting portion of the pipe, and contains triiron tetraoxide and / or acicular titanium oxide. Has an inner circumference 3 made of the same material as the pipe,
Furthermore, a cylindrical core 2 made of the same material as the pipe is used, which has a hole 4 that does not penetrate from the outer circumference to the inner circumference and has a compound that emits an odor due to heat generation in the hole 4. The pipes are connected by applying microwaves. [Effect] A pipe can be easily connected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for connecting pipes by irradiating microwaves with a cylindrical core having a specific structure.

[0002]

2. Description of the Related Art Various proposals have been made for a method of connecting pipes molded of a thermoplastic resin. As a heat fusion method, a conductive pattern such as a nichrome wire is embedded in the resin to flow an electric current. A method of fusion by Joule heat (Japanese Patent Publication No. 61-41293, Japanese Patent Publication No. 64-74381, etc.) and a method of heating by irradiation of electromagnetic waves using a resin in which a substance that absorbs various electromagnetic waves and converts them into heat is dispersed. 3-186690, JP-A-2-261626, etc.).

The method using electromagnetic waves is characterized in that it can be heat-fused in a non-contact state and that a jig for bonding can be easily formed.

[0004]

Although the method of irradiating electromagnetic waves has the advantages as described above, it is necessary to seal it so that the electromagnetic waves do not leak outside when actually performing construction. There was a problem that it was difficult to judge from outside the seal.

[0005]

Means for Solving the Problems The inventors of the present invention completed the present invention by intensively studying a method for connecting pipes inexpensively and easily by solving the above problems.

That is, the present invention relates to a method for connecting a pipe made of a thermoplastic resin by irradiating with microwaves by using a cylindrical core provided in contact with the outer surface of the pipe at the connecting portion. Core has an inner circumference made of the same material as the pipe, which contains ferrosoferric oxide and / or acicular titanium oxide, and has a non-penetrating hole provided from the outer circumference to the inner circumference. In addition, the pipe connecting method is characterized in that a compound that emits an odor due to heat is present in the hole that does not penetrate.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the resin forming the pipe is not particularly limited as long as it is thermoplastic, and specifically, polyvinyl alcohol, polyvinyl acetate, polyamide, polyethylene, polypropylene, or ethylene, propylene. Polyolefins such as copolymers, polystyrene, polyvinyl chloride, polyvinylidene chloride, polymethyl methacrylate, or copolymers such as styrene, vinyl chloride, methyl methacrylate, vinylidene chloride, polycarbonate, polyamide, polyester, polyimide, polyether , Any engineering plastic such as a condensation-type engineering plastic such as polyetherketone or polyetheretherketone may be used.

The size, shape and molding method of the thermoplastic resin pipe are not particularly limited, as is clear from the spirit of the present invention.

In the present invention, commercially available iron tetraoxide can be used, and natural magnetite is finely pulverized, iron is burned in air, or iron (III) oxide is used.
Examples thereof include those obtained by reducing water with steam-containing hydrogen, and those obtained by finely pulverizing red hot iron with water vapor. The particle size of such ferrosoferric oxide is 1000 μm or less, preferably 0.01 to 100 μm.
Those having a size of about m are preferably used.

As the acicular titanium oxide, a commercially available acicular titanium oxide can be used. The acicular titanium oxide has a minor axis length of 0.01 to 10 μm and an aspect ratio of 5 to 1000, such as magnesium and calcium. It may be doped with another metal oxide, or may be doped with tin oxide, indium oxide, or the like to be conductive, or may be commercially available. The crystal form of titanium oxide may be either rutile type or anatase type, but it is necessary that the shape of fine particles is acicular.

In the present invention, the method of incorporating the above-mentioned iron (III) tetraoxide and / or acicular titanium oxide in the thermoplastic resin forming the inner circumference of the cylindrical core is not particularly limited, and a method capable of being well mixed. Any method is acceptable as long as it is. For example, a solution of polymer could be iron (III) tetraoxide and / or
Alternatively, it is also possible to mix acicular titanium oxide and mix well by a known mixing method such as a ball mill or a homogenizer to disperse and then mold and dry it into the shape described below.
It is preferable to heat-melt mix the powder of the thermoplastic resin with the iron trioxide and / or the acicular titanium oxide. Specifically, after mixing the thermoplastic resin with ferrosoferric oxide and / or acicular titanium oxide with a Henschel mixer or the like, the mixture is heated and melted with an extruder, Brabender, etc., and then pelletized to give a cylindrical shape described later. The core is easy to mold.

Here, the thermoplastic resin and ferrosoferric oxide and /
Alternatively, the ratio of acicular titanium oxide is 100: 1 to 10
About 0: 500 (weight ratio), preferably 100: 10
It is about 100: 200 (weight ratio).

The shape of the cylindrical core in the present invention will be described below. FIG. 1 is a cross-sectional view of a connecting portion of a pipe, 1 is a cross section of a pipe to be connected, 2 is a cross section of a cylindrical core, and is made of the same material as the pipe. 3 is a part containing ferrosoferric oxide and / or acicular titanium oxide. Further, 4 is a hole opened from the outer circumference to the inner circumference of the cylindrical core. The size of the hole is not particularly limited as long as the odor is emitted to the outside, but even if it is large, it is necessary that the strength of the cylindrical core is not impaired. The depth of the hole is generally such that even if it is deep, it does not barely reach the layer containing ferrosoferric oxide or acicular titanium oxide, and preferably the thickness to be heated and melted at the time of fusion bonding. It is preferable that only a layer of the sand remains.

In the present invention, a compound that emits an odor by heating is placed in the bottom of the hole, and it is determined whether or not the heat required for fusion is generated by knowing that the heat is also transferred to that portion.

The compound that emits an odor by heating is not particularly limited as long as it does not generate heat by absorbing microwaves, but is not particularly limited, but preferably emits an odor near the temperature at which the resin used melts. Moreover, the odor is not toxic and does not have an unpleasant odor. In order to control the degree of odor, it is possible to devise a method of diluting or covering with another substance such as a resin or an inorganic compound. Specifically, various commercially available fragrances can be used as they are or after further dilution.

FIG. 2 is a vertical sectional view of the connecting portion of the pipe.
3 are the same as in FIG. Reference numeral 5 represents a connecting portion of a cylindrical core. In this example, the one having the connecting portion of the cylindrical core is shown, but the present invention is not limited to this. In this example, the cylindrical cores are connected at 5 parts and are usually reinforced with resin bolts. When the bolt is tightened, pressure is applied so that the cylindrical core and the outer circumference of the pipe come into close contact with each other.

The assembly of the pipe and the cylindrical core as described above is then irradiated with microwaves. Microwaves can be heated to the extent that the thermoplastic resin is sufficiently fused with a wavelength and energy that are commercially available as microwave ovens for household use, and microwaves with a frequency of several gigahertz (usually 2.45 gigahertz) are generated. Available, several KW /
Energy of about 1 kg is sufficient.

[0018]

The present invention will be further described with reference to examples.

Example 1 15 g of triiron tetraoxide (reagent manufactured by Wako Pure Chemical Industries, Ltd.) and high-density polyethylene (brand name: Stafrene E manufactured by Nippon Petrochemical Co., Ltd.)
792) 20 g was mixed well at 240 ° C. with a Labo Plastomill R type (manufactured by Toyo Seiki Seisakusho KK) This operation was repeated to obtain about 100 g of the mixture. 220 ° C of the mixture
A sheet having a thickness of 1 mm was formed by press molding. on the other hand,
High-density polyethylene (brand name: Staflen E801) manufactured by Nippon Petrochemical Co., Ltd. was similarly press-molded to obtain a sheet having a thickness of 4 mm.

90 mm × 1 mixed with ferrosoferric oxide
It was cut out into a sheet of 60 mm, and the high-density polyethylene was cut out into 100 mm × 170 mm and overlapped and press-molded at 230 ° C. to obtain a composite sheet having a thickness of 3 mm. When a sheet made by the same operation was cut in the middle, the thickness of the polyethylene part and the ferrosoferric oxide-containing part was 2.4 mm and 0.8 mm.
Was thick.

This sheet was covered with a pipe having an outer diameter of 50 mm and a thickness of 5 mm (formed by extrusion molding with high density polyethylene (brand name: Staflen E801) manufactured by Nippon Petrochemical Co., Ltd.), and the inside was covered with 43 pieces. 24 as iron oxide containing part
A cylindrical core was molded on the outer surface of the pipe by heat molding at 0 ° C. Further, four holes having an inner diameter of 5 mm and a depth of 2 mm were formed on the outside. On the bottom of this hole, a molded product obtained by dispersing ethylene brushlate as a fragrance in polyethylene wax to a concentration of 0.1% was adhered. The core connection is about 2
It was set to 0 mm and connected with nylon bolts. The microwave oven was radiated with microwaves placed in a commercially available microwave oven (Toshiba microwave oven ERT-540F manufactured by Toshiba) as shown in Figs. I stopped irradiating, and took out the bolts, and when I removed them, they were well bonded. I inserted a knife into the connection part and pierced it, but it did not come off. Further, when the bonded portion was cut into slices and the bonding state of the cylindrical core and the pipe was observed, they were completely bonded.

[0022]

INDUSTRIAL APPLICABILITY By carrying out the method of the present invention, a pipe can be easily connected, which is extremely valuable industrially.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a connecting portion of a pipe provided with a cylindrical core according to the present invention.

FIG. 2 is a vertical sectional view of a connecting portion of a pipe provided with a cylindrical core according to the present invention.

[Explanation of symbols]

1 Cross-section of pipe to be connected 2 Cross-section of cylindrical core 3 Inner circumference containing ferrosoferric oxide and / or acicular titanium oxide 4 Hole provided from outer circumference to inner circumference of cylindrical core 5 Cylindrical Core connections

Claims (1)

[Claims] 1. A method for connecting a pipe made of a thermoplastic resin by irradiating with microwaves using a cylindrical core provided in contact with an outer surface of the pipe at a connecting portion, wherein the cylindrical core is , Having an inner circumference made of the same material as the pipe, containing ferrosoferric oxide and / or acicular titanium oxide, and having a non-penetrating hole provided from the outer circumference toward the inner circumference, and A method for connecting pipes, wherein a compound that emits an odor due to heat is present in a hole that does not penetrate.