JPH07178817A - Fusion bonding method for thermoplastic resin molding - Google Patents

Abstract

PURPOSE:To easily perform heating and fusion bonding by covering a resin molding in which electroconductive minute particles are dispersed with thermoplastic resin, and holding the resin molding between the fusion bonding parts of at least two thermoplastic resin moldings, and then applying microwave to simplify the heat bonding. CONSTITUTION:A resin molding in which electroconductive minute particles are displayed is covered with thermoplastic resin. The resin molding is held between the fusion bonding parts of at least two thermoplastic resin moldings to be heat bonded, and then microwave is applied thereto. As the electroconductive minute particles, graphite, indiumoxide, the polymer of a heterocyclic five-membered ring compound or polyaniline whose particle diameter is preferably regulated to <=10mum in particular are exemplified. In the case of superposing and bonding a form e.g. a cylindrical form convenient to fusion bond at least two theremoplastic resin moldings to be fusion bonded, a short cylindrical form may by contrived to have a thickness to enter the interval in the case of inserting one side of cylinder into the other side of cylinder.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for fusing a thermoplastic resin molding. More specifically, the present invention relates to a method of heating, melting, and fusing by microwave using a specific method.

[0002]

2. Description of the Related Art A method of assembling resin molded products and adhering them to form a complicated molded product has been widely adopted. In the case where there is no effective adhesive such as polyolefin, or in the case where reliability is required, the heat fusion method is adopted.

[0003]

The method of heat fusion is as follows:
It is highly reliable because it melts and bonds the adhesive surface, but to melt only the adhesive surface, it is difficult to mold the molded product, such as embedding a metal near the adhesive part and performing dielectric heating. The equipment is also expensive. On the other hand, a method has been proposed in which a polyolefin that can be dielectrically heated by microwaves is used as an adhesive layer in which an organic solvent is swollen or gelled (JP-A-3-69342). There is a problem of volatilization when the waves are applied.

[0004]

[Means for Solving the Problems] The present inventors have completed the present invention by intensively studying a method capable of solving the above-mentioned problems and enabling simple heat fusion.

That is, according to the present invention, in a method of heat-sealing at least two thermoplastic resin moldings, at least a heat-sealing molding of a resin molding in which conductive fine particles are dispersed is covered with a thermoplastic resin. It is a method of fusing a thermoplastic resin molded article, which comprises sandwiching the two thermoplastic resin molded articles between fusion bonded parts and then irradiating a microwave.

In the present invention, the thermoplastic resin forming the thermoplastic resin molded product is not particularly limited, and may be a polymer having any structure as long as it can be melt-molded by heating. Specifically, polyolefins such as polyethylene, polypropylene, or copolymers of ethylene, propylene, etc., polystyrene, polyvinyl chloride, polyvinylidene chloride, polymethylmethacrylate, or styrene, vinyl chloride, methylmethacrylate, vinylidene chloride, etc. Any material such as a polymer, a condensation type engineering plastic such as a polycarbonate, a polyamide, a polyester or a polyimide may be used.

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

In the present invention, as the conductive fine particles, graphite, indium oxide, a polymer of a hetero five-membered cyclic compound or polyaniline having a particle diameter of 100 μm or less, preferably 50 μm or less, particularly preferably 10 μm or less is exemplified. It As long as it is electrically conductive, its surface may be treated to improve dispersibility. Here, as the polymer of the five-membered heterocyclic compound, those obtained by polymerizing thiophene, pyrrole and furan with an oxidizing agent can be used. Similarly, polyaniline can be obtained by polymerizing aniline with an oxidizing agent. Here, as the polyaniline, a polyaniline soluble in a specific solvent is known, but such a polyaniline can also be used. Examples of the oxidizing agent include ferric chloride, salts of persulfate such as ammonium persulfate, hydrogen peroxide solution, tungsten chloride, antimony chloride, arsenic pentafluoride and the like.

These fine particles are used as a resin molded product obtained by dispersing and molding the fine particles in a polymer. Any polymer may be used for dispersion,
In some cases, it is also preferable to use the above-mentioned thermoplastic resin which forms a thermoplastic resin molded product to be fused. Specifically, polyvinyl alcohol, polyvinyl acetate, polyolefin, polystyrene, polyvinyl chloride, polymethylmethacrylate, polycarbonate, polyester, polyamide and the like can be exemplified. Further, it is of course possible to use other resins and thermosetting resins, and examples of such resins include polyimide, epoxy resin, phenol resin, polycarbodiimide and the like.

In the present invention, the method of dispersing the conductive fine particles in the polymer is not particularly limited, and any method can be used as long as it can be mixed well. For example, it is also possible to mix conductive fine particles with a polymer solution and mix them well by a known mixing method such as a ball mill and a homogenizer to disperse them and then mold and dry them into a desired shape, and particularly a thermosetting resin. Is preferred as the dispersion medium. Further, in the case of a thermoplastic resin, the polymer and the conductive fine particles can be melted by heating and mixed and then molded into a desired shape.

When the conductive fine particles are dispersed in the polymer solution, the solvent of the polymer solution is not particularly limited as long as it can dissolve the polymer, but is not limited to water, a hydrocarbon compound, a halogenated hydrocarbon compound, and an aroma. Examples thereof include group hydrocarbon compounds, esters, ethers, amides, alcohols and ketones. As polymer concentration, 1-50w
t%.

The ratio of the polymer as the dispersion medium and the conductive fine particles is about 100: 5 to 100: 500 (weight ratio), preferably 100: 10 to 100: 200.
(Weight ratio).

The resin molding in which the conductive fine particles thus obtained are dispersed is covered with a thermoplastic resin. As the thermoplastic resin used here, it is more effective to use the same one as that constituting the thermoplastic resin molded product to be bonded. Usually, it is sufficient to completely cover the resin molded product in which the conductive fine particles are dispersed, and there is no limitation on the shape and thickness,
A shape that is convenient for fusing at least two thermoplastic resin moldings to be heat-fused, for example, to stack and bond cylindrical ones, when inserting one cylinder into the other. A device such as a cylindrical shape having a short thickness that fits in the space may be used. In addition, when the strength of the resin molded product in which the conductive fine particles are dispersed is not sufficient, it is preferable to take measures such as making the thickness of the thermoplastic resin used to cover the resin molded product relatively thick.

In the present invention, a resin molded product in which conductive fine particles covered with a thermoplastic resin are dispersed is sandwiched between the fused portions of at least two thermoplastic resin molded products, and then the molded product is irradiated with microwaves. To be done. During irradiation, it is preferable that when the resin is melted by applying pressure to the adhesive portion, the resin is sufficiently fused. Microwaves can be sufficiently fused with a wavelength and energy that are commercially available as household microwave ovens, microwaves with a frequency of several gigahertz can be used, and energy of several KW / 1 Kg is sufficient.
If it is a small molded product, put it in a commercially available microwave oven for several seconds ~
It can be fused by irradiating the microwave for several minutes.

[0015]

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

Example 1 A film having a thickness of about 30 μm was obtained by casting a slurry prepared by dispersing 1 g of graphite powder manufactured by Wako Pure Chemical Industries, Ltd. in a polypropylene carbonate solution (a solution of 2 g of polypropylene carbonate dissolved in 4 ml of methyl ethyl ketone). It was This film was made into a strip shape of 10 cm × 0.5 cm, and sandwiched between two commercially available polyethylene sheets strip-shaped (11 cm × 1 cm × 0.1 mm, melting point 135 ° C.), and heated and pressed at 240 ° C. for 1 minute. (20kg /
cm ² ) to obtain a strip-shaped molded product having a thickness of 0.1 mm. Cut off the edge of this molded product (11 cm x 1 cm x
0.1 mm).

This molded product was converted into two commercially available polyethylene sheets (10 cm × 10 cm × 0.1 mm, melting point 135).
(° C.) was sandwiched between the overlapped portions by 1 cm and overlapped. A microwave oven (Toshiba microwave oven ERT manufactured by Toshiba
-540F) while pressurizing with 100 g of glass,
Irradiated with microwave for 1 minute. When the sheet was taken out and observed, it was observed that the sheet was fused in a width of about 0.5 mm. When this sheet was pulled by Instron, the sheet was cut before the adhesive surface was cut. When the adhered sheet was further irradiated with microwaves for 1 minute,
The bonded part was heated more than the other parts but did not melt.

Example 2 The polypropylene carbonate film having the graphite dispersed therein obtained in Example 1 was replaced with a polyethylene sheet, and a strip of polystyrene film (11 cm × 1 cm ×) was used.
0.5 mm) to make a polystyrene-covered molded product, and use a commercially available polystyrene sheet (10 cm × 10
(cm × 3 mm), 1 cm of two sheets were superposed, and the molded product covered with the polystyrene was sandwiched therebetween, and the same procedure as in Example 1 was carried out. As a result, the polystyrene sheet was completely fused.

Example 3 Indium oxide (Fuji Titanium Co., Ltd.) was used as a conductive powder.
Made of fine-grained ITO (Type-B) and used as a polymer of a polymer of cyclic olefin (manufactured by ZEON CORPORATION, ZEONE
X280) was used, and a slurry of conductive fine particles was prepared in the same manner as in Example 1 except that chloroform was used as a solvent, and a film having a thickness of 40 μm was similarly prepared by casting. This film is used as a molded product in which conductive fine particles are dispersed, and a polyethylene sheet having a thickness of 1 m.
A molded article covered with polyethylene was prepared in the same manner as in Example 1 except that the resin having a diameter of m was used (10 cm × 1 cm × 1 m).
m).

As a molded product to be adhered, two commercially available polyethylene sheets (10 cm × 10 cm × 3 mm) were superposed on each other by 1 cm, and the molded product covered with the polyethylene was sandwiched therebetween, and the same procedure as in Example 1 was carried out. The sheets were completely fused. When the bonded sheet was further irradiated with microwaves for 1 minute, the bonded part was heated more than other parts but did not melt.

[0021]

Industrial Applicability By carrying out the method of the present invention, a resin molded product can be easily bonded, and even if it is irradiated with a microwave after bonding, it is safe because it does not melt again due to overheating and has an extremely industrial value. is there.

Claims (2)

[Claims] 1. A method of heat-sealing at least two thermoplastic resin moldings, wherein at least two heat-bonding moldings in which a resin molding in which conductive particles are dispersed are covered with a thermoplastic resin are heat-sealed. A method for fusing a thermoplastic resin molded article, which comprises sandwiching the thermoplastic resin molded article between fused parts and then irradiating a microwave. 2. The method according to claim 1, wherein the conductive fine particles are fine graphite, fine indium oxide, a polymer of a five-membered heterocyclic compound, or polyaniline.