JPH06218863A - Conductive plate-shaped molded product - Google Patents

Abstract

PURPOSE:To enhance the conductivity, mechanical strength and durability as an electrode of a conductive plate-shaped molded product usable as an electrode. CONSTITUTION:A conductive plate-shaped molded product is obtained by integrally bonding and welding a surface layer having conductivity higher than that of a plate-shaped base material molded from a synthetic resin containing a conductive fiber such as a carbon fiber or a metal fiber to at least the single surface of the base material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive plate-shaped molded product which has excellent conductivity and mechanical strength and is suitable for use in electrodes and the like.

[0002]

2. Description of the Related Art Metallic materials, carbonaceous materials, graphite materials and the like are known as conductive materials for use in electrodes and the like. Among these materials, the metal material has high conductivity,
Although it is excellent in mechanical strength, it has a disadvantage that it is ionized or eluted by energization, resulting in severe wear. In particular, when heavy metals such as chrome are contained, there is a problem that the elution thereof pollutes the environment. On the other hand, carbonaceous materials and graphite materials consume less when used for electrodes, etc., but have low mechanical strength,
It cannot be used when strength is required.

[0003] Further, a molded plate of synthetic resin to which a conductive filler such as metal fiber or carbon fiber is added is known, but in this case, the metal fiber or carbon fiber plays a role of a reinforcing material and has a mechanical strength. However, the conductivity was insufficient.
Further, a carbon fiber / carbon composite material obtained by firing a carbon fiber reinforced resin molded plate is known, but this has high conductivity and consumes less electricity, but it requires a firing process, so The cost was high and the mechanical strength was insufficient depending on the application.

On the surface of the synthetic resin molded plate to which the above-mentioned conductive filler is added, a cloth or felt made of carbon fiber,
Alternatively, a conductive material to which a resin paste containing a conductive powder is attached is known (Japanese Patent Publication No. 3-58149, JP-A-58-166050 and JP-A-60-22).
1909), there is a problem in this case that the conductivity is not sufficient.

[0005]

DISCLOSURE OF THE INVENTION The present invention is a conductive plate-shaped molding which is excellent in conductivity and mechanical strength, and is suitable for electrodes because it is less consumed by energization and can be manufactured at low cost. It is to provide goods.

[0006]

The present invention is directed to a carbon fiber,
That a surface layer having a higher conductivity than the plate-shaped substrate is integrally provided by adhesion, fusion bonding, etc. on at least one surface of the plate-shaped substrate formed of a synthetic resin containing a conductive fiber such as a metal fiber. It is a characteristic conductive plate-shaped molded product.

The conductive fibers used in the present invention are short fibers or long fibers such as carbon fibers and metal fibers. Further, the plate-shaped substrate, the conductive fiber and the unsaturated polyester resin,
It is manufactured by press-molding and curing a molding compound with a thermosetting resin such as vinyl ester resin or epoxy resin. Further, a thermoplastic resin such as nylon, polyester, polyethylene, or polypropylene can be used. In this case, it can be produced by mixing the above-mentioned conductive fiber with a thermoplastic resin in a molten state, cooling and solidifying. it can. Further, the thermoplastic resin is used in the form of a fiber, which is mixed with the above conductive fibers to form a woven fabric, a knitted fabric, a non-woven fabric, or a sheet-like or mat-like form of felt, etc. The fibers can be softened and then cooled and solidified to form a plate, and the above fibers are preferably polyethylene fibers or polypropylene fibers, and the conductive fibers are preferably carbon fibers.

The plate-like base material made of the above-mentioned synthetic resin is given conductivity by the addition of conductive fibers, and at the same time, the mechanical strength is improved and the bulk density is increased. In this case, the amount of conductive fibers added is such that the bulk density of the plate-shaped substrate is 1.2 to 5.0.
g / cm ³ , its volume resistivity is less than 1Ω · cm in the direction along the plate surface and less than 10Ω · cm in the thickness direction of the plate surface, and its bending strength is 5 kg / mm ² or more. In other words, the volume fraction of the conductive fiber is preferably 5 to 70%, and 5%
If it is less than 70%, the conductivity will be insufficient and the strength will be insufficient.
When it exceeds, the consumption of metal fibers due to energization becomes excessive. In addition, a conductive powder, a thickener, a low-shrinking agent, and an internal release agent can be added to the plate-shaped substrate.

The surface layer provided on one side or both sides of the plate-like substrate is a plate-like or sheet-like continuous body made of carbon or graphite, such as a carbon sintered plate, or crushed pieces of carbon plate or graphite particles. The discontinuous layer may be any discontinuous layer formed of an array of such granular materials, and these are fixed to the plate-shaped substrate by adhesion or integral molding. The thickness of the surface layer is preferably ⅓ or less of the thickness of the plate-shaped substrate, and the volume resistivity value is smaller than that of the plate-shaped substrate and preferably less than 0.1 Ω · cm. It should be noted that the outer surface of the surface layer may be further coated with a thin resin film or a thin woven fabric, knitted fabric, non-woven fabric, felt or the like made of carbon fiber or synthetic fiber. In addition, binders for increasing the adhesiveness between the conductive material and the resin component can be added to the plate-shaped base material and the surface layer.

[0010]

The conductive plate-shaped molded article of the present invention is a plate-shaped base material made of a synthetic resin containing conductive fibers and a highly conductive surface layer, which are integrated by adhesion, fusion, or the like. Only the conductive fiber contained in the base material is supplemented by a highly conductive surface layer that lacks conductivity, and since the plate-shaped base material contains the conductive fiber, the mechanical strength as a whole is improved, Moreover, since the firing process is not required, the manufacturing cost can be reduced. In particular, when carbon fibers are used as the conductive fibers and the surface layer is formed of carbon or graphite, the consumption due to the energization is further reduced.

[0011]

【Example】

Example 1 100 parts of vinyl ester resin, 50 parts of PAN-based carbon fiber chopped fiber (average fiber length 3 mm) and 130 parts of graphite powder were kneaded to prepare a sheet-shaped molding compound having a thickness of 10 mm. A 2 mm thick carbon thin plate (volume specific resistance 0.0008 Ω · cm) is placed in the mold, the above-mentioned sheet molding compound is overlaid thereon, and a heat press at a temperature of 135 ° C. and a pressure of 60 kg / cm ² is applied to 10
Conducting for 1 minute, a conductive plate-shaped molded product having a thickness of 7 mm was produced.

Example 2 Granular graphite having a particle size of 1 to 2 mm (volume resistivity 0.0
(007 Ω · cm) is evenly placed on top of which carbon fiber 70
Unit weight of 1600 parts and 30 parts of polyethylene fiber
Four sheets of softened g / m ² felt were heated at 200 ° C for 3 minutes and placed on top of each other, and the temperature was 50 ° C and the pressure was 100 ° C.
A kg / cm ² hot press was applied for 1.5 minutes to prepare a conductive plate-like molded product having a thickness of 5 mm.

Example 3 Granular graphite having a particle diameter of 1 to 2 mm (volume resistivity 0.0
(007 Ω · cm) is evenly placed on top of which carbon fiber 60
Unit weight consisting of 40 parts and 40 parts of polypropylene fiber
Four sheets of softened 0 g / m ² felt were heated at 220 ° C for 3 minutes and placed on top of each other, and the temperature was 70 ° C and the pressure was 10
A hot press of 0 kg / cm ² was applied for 1.5 minutes to prepare a conductive plate-shaped molded product having a thickness of 5 mm.

Comparative Example 1 A commercially available carbon sintered plate (manufactured by Owada Carbon Co., Ltd., 0C.C)
ARBON OT-2410) was prepared.

Comparative Example 2 Using only the kneading molding compound of Example 1, the same hot pressing as in Example 1 was carried out to produce a conductive plate-shaped molded article composed of only a plate-shaped substrate.

Comparative Example 3 Only the softened felt of Example 3 was used,
The same hot pressing as in Example 3 was carried out to produce a conductive plate-shaped molded product.

The conductive plate-like molded products of Examples 1 to 3 and Comparative Examples 1 to 3 were tested for volume resistivity and durability as electrodes by the following methods. The test results of Examples 1 to 3 are shown in Table 1, and the test results of Comparative Examples 1 to 3 are shown in Table 2.

Method for measuring volume resistivity The values in the direction along the plate surface are 100 mm in length, 10 mm in width, and 3 mm in thickness. A test piece is prepared, and silver paste is applied to both end surfaces in the longitudinal direction. Was measured with a digital multimeter (Yokogawa Electric Co., Ltd., YOKOGAWA 7552) by the 4-terminal method. As for the value in the thickness direction, a test piece having a length of 10 mm, a width of 10 mm and a thickness of 3 mm was prepared, silver paste was applied to both upper and lower surfaces, and the resistance therebetween was measured in the same manner as above.

Durability Evaluation Method as Electrode 10 pieces of the above-mentioned electroconductive plate-shaped molded articles were used as electrodes in a tank in which an aqueous solution of 1.5 g / liter of sodium chloride was circulated.
They are installed facing each other at an interval of mm (however, in Examples 1 to 3 having a surface layer, the surface layers are opposed to each other), and a direct current having a current density of 30 mA / cm ² is continuously applied by constant current control, The durability as an electrode was evaluated by measuring the time for which a current density of 30 mA / cm ² was maintained at a maximum voltage of 18 volts.

Table 1 Example 1 Example 2 Example 3 Bulk density of base material (g / cm ³ ) 1.52 1.42 1.35 Volume resistivity of base material Direction along plate surface (Ω · cm) 0.024 0.007 0.011 Plate surface Thickness direction (Ω · cm) 0.093 0.405 0.803 Bending strength of base material (kg / mm ² ) 8.0 13.5 12.3 Volume resistivity of surface layer (Ω · cm) 0.0008 0.0007 0.0007 Durability as an electrode (time) 50 or more Over 50 over 50

Table 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Bulk density of base material (g / cm ³ ) 1.75 1.52 1.35 Volume resistivity of base material Direction along plate surface (Ω · cm) 0.0008 0.024 0.011 Plate surface Thickness direction (Ω · cm) 0.0008 0.093 0.803 Bending strength of base material (kg / mm ² ) 2.0 8.0 12.3 Durability as an electrode (time) 50 or more 0.2 0.4

As is clear from Tables 1 and 2, in Examples 1 to 3 of the present invention, the volume resistivity of the surface layer is small, the bending strength of the substrate is large, and the durability as an electrode is high. Is excellent. On the other hand, Comparative Example 1
Is a single carbon sintered plate, it has a small volume resistivity and excellent durability as an electrode, but has a low bending strength. Further, Comparative Examples 2 and 3 have no surface layer, and thus have poor durability as an electrode.

[0022]

As described above, the conductive plate-shaped molded article of the present invention has a surface having higher conductivity than the plate-shaped base material on at least one surface of the plate-shaped base material made of synthetic resin containing conductive fibers. Since it is provided with a layer, it is excellent in both electrical conductivity and mechanical strength, has little wear due to energization when used as an electrode, can withstand long-term use, and is manufactured by molding using a mold. Since it does not require firing, the manufacturing cost can be reduced, and it is particularly useful for an electrode requiring mechanical strength.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masayuki Kakiuchi, 1-2-6 Dojimahama, Kita-ku, Osaka City, Osaka Prefecture Toyo Kasei Co., Ltd. (72) Inventor, Yukihiko Naka 1 Sanmeicho, Abeno-ku, Osaka-shi, Osaka Chome 3-29

Claims (7)

[Claims] 1. A surface layer having a conductivity higher than that of the plate-shaped substrate is bonded or fused to at least one surface of the plate-shaped substrate formed of a synthetic resin containing a conductive fiber such as carbon fiber or metal fiber. An electrically conductive plate-shaped molded product characterized by being integrally provided with, for example. 2. The conductive plate-shaped molded article according to claim 1, wherein the plate-shaped substrate is composed of conductive fibers and a thermosetting resin. 3. The conductive plate-shaped molded article according to claim 1, wherein the plate-shaped substrate is composed of conductive fibers and a thermoplastic resin. 4. A woven fabric, knitted fabric, non-woven fabric or felt whose plate-shaped base material is composed of conductive fibers and thermoplastic synthetic fibers is heated to soften the thermoplastic synthetic fibers, and then obtained by cooling and solidifying. The electroconductive plate-shaped molded article according to claim 1, which is a plate-shaped body. 5. The conductive plate-shaped molded article according to claim 4, wherein the conductive fibers are carbon fibers and the thermoplastic synthetic fibers are polyethylene fibers or polypropylene fibers. 6. The plate-shaped substrate has a bulk density of 1.2 g / cm ³ or more and a volume resistivity value of 1 Ω · cm in the direction along the plate surface.
The conductive plate-like molded article according to any one of claims 1 to 5, wherein the conductive plate-like molded article has a bending strength of 5 kg / mm ² or more and a bending strength of 5 kg / mm ² or more. 7. The conductive plate-like molded article according to claim 1, wherein the surface layer is formed of carbon or graphite and has a volume resistivity value of less than 0.1 Ω · cm.