JPH0422012A - Manufacture of conductive resin molding - Google Patents

Abstract

PURPOSE:To improve surface conductivity by heating at a higher temperature than a glass transition temperature and pressing a surface of a conductive molding containing a conductive material in a synthetic resin. CONSTITUTION:A surface of a conductive molding 1 containing a conductive material in a synthetic resin is heated at a higher temperature than a glass transition and pressed. As synthetic resins used, polyvinyl chloride, chlorinated polyethylene, polyethylene, polypropylene, polystyrene or these mixture or a copolymer composed mainly of these resins or the like is suitably used. This synthetic resin needs to contain a conductive material and as conductive materials, carbon black having surpassing conductivity, graphite and metal powder of copper and the like, and metallic fiber and the like can be suitably used and 100wt.pts. of the synthetic resin is used after mixed with 10-100wt.pts., as an approximate range, of the conductive material. Thereby the conductive resin molding 1 surpassing in the conductivity can be easily obtained.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for manufacturing a conductive resin molded article made by mixing a conductive material such as carbon black or metal powder into a synthetic resin, and particularly relates to a method for manufacturing a conductive resin molded article by mixing a conductive material such as carbon black or metal powder into a synthetic resin. The present invention relates to a manufacturing method that allows molded products with good properties to be obtained.

(Prior art and its problems) In recent years, conductive resin molded products made by mixing synthetic resin with conductive materials such as carbon black and metal powder have been used as antistatic materials and electromagnetic shielding materials for electronics. has been done.

Such molded products are manufactured using various molding methods, but when the molded product is cut, machined, or drilled, the electrical conductivity of its surface becomes lower than that of other parts. there were. Furthermore, when other conductive materials such as metal terminals are bonded, there is a problem in that the conductivity of the bonded portion is poor.

(Means for Solving the Problems) The present invention has discovered that good conductivity can be obtained by pressing the surface of a molded article at a temperature higher than the glass transition temperature of the synthetic resin used, and the above problems can be solved. The gist of this is that the surface of a conductive resin molded article containing a conductive material in a synthetic resin is heated and pressed at a temperature equal to or higher than the glass transition temperature of the synthetic resin to improve the conductivity of the surface. A method for producing a conductive resin molded article is provided.

As the synthetic resin used in the conductive resin molded article of the present invention, polyvinyl chloride, chlorinated polyethylene, polyethylene, polypropylene, polystyrene, mixtures thereof, copolymers mainly composed of the above resins, etc. can be suitably used. This synthetic resin needs to contain a conductive material, and as the conductive material, carbon black with excellent conductivity, metal powder such as graphite and copper, metal fiber, etc. can be suitably used. 10 to 10 parts by weight
They are mixed and used in a range of about 0 parts by weight.

Conductive resin molded products can be molded into plate shapes or various shapes using conventional molding methods such as extrusion, heat press, calendaring, and injection molding using the above-mentioned compound. It can also be used when laminated with an insulating resin layer. The electric paper resistance of conductive resin molded products is 10 to 102 in terms of volume resistivity.
A value of approximately Ω·CIm is suitable.

In the present invention, it is necessary to heat the synthetic resin used for the conductive resin molded article to a temperature higher than the glass transition temperature and press the surface.

The heating temperature is preferably higher than the glass transition temperature, and the melting point is preferably about ±50°C. If the temperature is lower than the heating temperature or the glass transition temperature, pressing the area will not produce an effect of improving conductivity.

In addition, the degree of pressure varies depending on the heating temperature, but considering workability etc., it is 1 to 10k (approximately 1/-, heating time is 0,
About 5 to 2 seconds is preferable.

The reason why conductivity is improved by the above method is not clear, but when a conductive resin molded product is subjected to cutting or machining, the processed surface of the conductive resin molded product is locally pulled, causing the conductive materials to interact with each other. This is presumed to be due to a decrease in the contact point between the resin and the conductive material, or the generation of fine voids (spaces) between the resin and the conductive material. Therefore, by pressing the machined surface at a temperature higher than the glass transition temperature of the synthetic resin used, the contact points between the conductive materials are restored and the voids disappear, and the machined surface also has the inherent conductivity of the conductive resin molded product. It is thought that gender is reproduced.

In the present invention, the conductive resin molded product can be used alone, but it can also be used for molded products bonded with other conductive materials.As the conductive material, the same content as the above-mentioned conductive resin molded product or metal terminals such as word lines can be used. Can be used.

The metal terminal may vary depending on the purpose of use, or one made of conductive metal such as stainless steel, copper, iron, titanium, etc. can be suitably used.

(Example) Examples of the present invention will be described below with reference to the accompanying drawings. 1st
The figure is a perspective view showing an example of a plate-shaped conductive resin molded product 1, and shows an example of a conductive resin plate containing a conductive material in a synthetic resin.

2 to 4 are process schematic diagrams showing embodiments of the present invention,
5 to 7 are process schematic diagrams showing an embodiment using a metal terminal as the conductive material, FIG. 8 is a sectional view showing another embodiment using a metal terminal, and FIGS. 9 and 10 are It is a perspective view showing an example of a metal terminal.

The plate-shaped conductive resin molded article 1 shown in Fig. 1 is a polyethylene plate (thickness: 111'll; glass transition temperature of polyethylene used - -120°C; melting point = 115°C),
Length 200rnra using a circular saw! It was cut into a size of 20+nn+.

Of this cut surface, both end faces on the 20+++n+ width side are 10
After pressing with a pressure of 2 kq/aIl using a hot plate heated to 0°C, conductive paint 2 was applied, and the electrical resistance value between both end faces was measured and found to be 350Ω.

On the other hand, the electrically conductive resin plate coated with electrically conductive paint, which is heated and pressed, has a resistance value of 1.3.
It was Ω.

2 to 4 show other embodiments of the present invention. As shown in the cross-sectional view of FIG. A laminate board 7 is used.

Here, the conductive resin molded article 1 is made of a polyvinyl chloride resin plate containing 10% by weight of carbon black as a conductive material, thickness 11, glass transition temperature of the polyvinyl chloride resin used = 87°C, melting point = 202°C ), and the insulating resin layer 3 consists of only the above-mentioned polyvinyl chloride resin (thickness 111
), and after placing them in the order shown in Figure 2, the heating temperature is 180℃ and the pressure is ! Pressing was carried out under the conditions of 50 kt/- to obtain a laminate 7. Next, as shown in FIG. 3 using the laminated plate 7 described in 1, a part of the insulating resin layer on one side is removed by cutting to expose a part of the surface of the conductive resin molded product and the exposed part 4 is removed. Three locations were formed.

The electrical resistance value between these three exposed portions 4 was 2.5Ω.

Further, the surface of the exposed portion 4 was subjected to a pressing treatment at 5 K (J/alt) using a hot plate heated to 160° C., and then the electrical resistance value was measured and found to be 515Ω.

Further, another conductive material 5 was joined to the exposed portion 4 using a polyvinyl chloride conductive welding rod as shown in FIG.

The conductive material 5 is the same as the plate-shaped conductive resin molded product 1 described above.

Here, when we measured the electrical resistance value between the conductive resin molded product 1 and the conductive material 5 for those joined without heating and pressing, it was 5.6Ω, whereas the heating and pressing The treated one had a good resistance of 1°IKΩ.

Further, FIGS. 5 to 7 show an embodiment in which a metal terminal such as a lead wire is used as the other conductive material 5, and the laminated plate 7 shown in FIG. 2 is used as shown in FIG. Like, diameter 1
The insulating resin layer 3 was removed by cutting into a cylindrical shape of 5 nnφ to form an exposed surface 4.

Next, apply a pressure of 5 k to the exposed surface using a hot plate heated to 160°C.
After pressing with g/aa, the metal terminal (contact part 12n+nφ with the conductive resin layer) shown in FIG. 10 is installed as shown in FIG. It was filled with an insulating resin 6 made of a vinyl chloride resin welding rod.

The resistance value between the conductive resin molded product 1 and the metal terminal was measured and found to be 510Ω.

On the other hand, when the resistance value was measured in the same manner for a product made using the same method as above except that no heating or pressing treatment was performed, the resistance value was 2.5Ω, indicating that the method according to the present invention is superior. I know that there is.

Although the above-mentioned metal terminals can be provided at any location depending on the application, FIG. 8 shows an example in which the metal terminals shown in the perspective view of FIG. 9 are used and are provided through the laminate. Indicated. The shape shown in the perspective view of FIG. 9 has the advantage of increasing the contact area with the exposed surface, and also has the advantage that the first
It is preferable that the contact portion has a large number of through holes as shown in FIG. 0, or that the contact portion has a mesh shape.

(Effects of the Invention) As described above, according to the present invention, a conductive resin molded product with excellent conductivity can be easily obtained, and a conductive resin molded product with excellent conductivity can be easily obtained. It has great applicability to resin molded products.

[Brief explanation of the drawing]

Figure 1 is a perspective view showing an example of a conductive resin molded product used in the present invention, Figures 2 to 4 are process schematic diagrams showing an embodiment of the present invention, and Figures 5 to 7 are conductive resin molded products. A process schematic diagram showing an example using a metal terminal as the material, FIG. 8 is a sectional view showing another example using a metal terminal, and FIGS. 9 and 10 are perspective views showing an example using a metal terminal. It is. 1... Conductive resin molded product 2... Conductive paint 3... Insulating resin layer 4... Exposed surface 5... Conductive material 7... Laminate patent applicant Mitsubishi Plastics Co., Ltd.

Claims (2)

[Claims] 1. heating the surface of a conductive resin molded article containing a conductive material in a synthetic resin at a temperature equal to or higher than the glass transition temperature of the synthetic resin;
A method for producing a conductive resin molded article, which comprises pressing to improve the conductivity of the surface. 2. 2. The method of manufacturing a conductive resin molded article according to claim 1, further comprising joining another conductive material to the surface of the heated and pressed conductive resin molded article.