JPH05221763A - High electric conductive material with metal layer - Google Patents

Abstract

PURPOSE:To provide a high electric conductive material applicable to a field requiring high electric conductivity by reducing the amt. of a metal stuck, lowering specific gravity and regulating the electric resistivity of a high electric conductive compsn. to 10<-3>-10<-4>OMEGA.cm. CONSTITUTION:A layer of at least one kind of metal selected among Pt, Au, Ru, Rh, Pd, Ni, Co, Cu, Cr, Sn and Ag is stuck to the surface of an electric conductive tin oxide/antimony oxide compsn. to obtain the objective high electric conductive material.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to highly conductive materials.

[0002]

2. Description of the Related Art In recent years, with the diversification of needs for conductive materials, development of highly conductive compositions and molded products has been desired, and development of highly conductive substances suitable as materials for conductive composite materials has been developed. Is desired.

Conventionally, as a conductive substance, various materials such as titanium oxide, needle-shaped titanium oxide, mica, shirasu balloon, glass beads, fibrous aluminum borate, fibrous magnesium borate, fibrous potassium titanate, and sepiolite. It is known that tin oxide / antimony oxide, indium oxide / tin oxide, or a metal film is adhered to the surface of such or other natural minerals.

The tin oxide / antimony oxide type conductive material has a conductivity of about 10 ⁴ to 10 ¹² Ω · cm and is widely used. It is used as a composition or a molded product obtained by mixing this with a resin or the like. It has a drawback that it cannot give a conductivity of 10 ⁴ Ω · cm or more.

[0005] Indium oxide / tin oxide type conductive materials are not widely used as fillers and are used in the field of films, but their fields of use are limited because they are expensive raw materials.

Since the conductive material with the metal film adhered is a thin film of metal adhered to the surface of various materials, it has a lower bulk specific gravity than conventional metal powders, but has low electrical conductivity. There are drawbacks. In order to improve the electrical conductivity, a large amount of metal film has to be attached, but in that case, the bulk specific gravity is inevitably increased. Therefore, it cannot be a conductive material having satisfactory electric conductivity and bulk specific gravity.

Furthermore, in the conventional conductive material, the conductivity is 1
In order to increase the conductivity to the extent that high conductivity in the range of 0 ⁻³ to 10 ⁴ Ω · cm is required, it is necessary to increase the amount of the metal used, but in this case, the specific gravity of the metal used is Due to its large size, the weight of products when finished into various products becomes heavy, so that the field of use of the products is currently limited.

Carbon powder has been conventionally used as a conductive material other than the above. However, conductive compounds containing carbon powder and molded products thereof have conductivity due to the bleeding phenomenon of the carbon powder over time. There are drawbacks such as deterioration and stains.

[0009]

The object of the present invention is to reduce the amount of deposited metal, to reduce the specific gravity, and to make the highly conductive composition have an electric conductivity of 10 ⁻³ to 10 ⁴ Ω · cm and high conductivity. It is to provide a highly conductive substance applicable to a field in which is required.

That is, according to the present invention, Pt, Au, Ru, Rh and P are formed on the surface of the tin oxide / antimony oxide type conductive material.
The present invention relates to a highly conductive substance, which is provided with an adhesion layer of at least one metal selected from the group consisting of d, Ni, Co, Cu, Cr, Sn and Ag.

As the tin oxide / antimony oxide conductive material of the present invention, conventionally known conductive materials are widely used, and specifically, titanium oxide, acicular titanium oxide, mica,
Examples of various materials such as shirasu balloon, glass beads, fibrous aluminum borate, fibrous magnesium borate, fibrous potassium titanate, sepiolite and other natural minerals with tin oxide / antimony oxide attached it can.

The highly conductive substance of the present invention comprises Pt, Au, Ru, Rh, Pd, Ni and C on the surface of the above conductive substance.
It is provided with an adhesion layer of at least one metal selected from the group consisting of o, Cu, Cr, Sn and Ag. The amount of the metal deposited is 30 wt% or less. When the amount of deposited metal exceeds 30 wt%, there is no significant difference in specific gravity and electrical conductivity as a composition from known metal-attached highly conductive substances, and industrial merits cannot be found.

The highly conductive substance of the present invention is produced, for example, by the following method. That is, the highly conductive substance of the present invention comprises: (a) an aqueous dispersion of an electrically conductive substance, (b) an aqueous solution or dispersion of the above-mentioned specific metal compound, (c) a reducing agent and, if necessary (d) ) Of the components selected from the group consisting of reduction catalysts, one component necessary for the reduction of the metal compound is added and an excess is added, and the remaining essential components that complete the reduction of the metal compound under stirring are continuously added. , Is produced by uniformly forming a metal in a thin film on the surface of a conductive substance. More specifically, the highly conductive substance of the present invention is produced by the methods shown in (1) to (3) below.

(1) A method in which a reducing agent is added with stirring to a mixed liquid of an aqueous dispersion of a conductive substance and an aqueous solution or dispersion of a metal compound, or a mixture obtained by adding a reducing catalyst thereto.

(2) A method of adding a reducing catalyst to an aqueous dispersion of a conductive substance, an aqueous solution of a metal compound or a mixed solution of an aqueous dispersion and a reducing agent while stirring.

(3) A method in which the aqueous dispersion of the conductive material is adjusted to a reducing atmosphere and then the aqueous aqueous solution or dispersion of the metal compound is added with stirring.

Further, as another method, the high-conductivity substance of the present invention can be produced by directly applying the technique of metal plating by the dipping method known as the chemical plating method.

The aqueous dispersion of the conductive material can be prepared by a usual powder dispersion method, but it is desirable that the conductive material be dispersed as much as possible. If the dispersion is insufficient, it is difficult to form the metal adhesion layer uniformly, and the conductivity of the obtained highly conductive substance is insufficient, which is not preferable. Therefore, when preparing the aqueous dispersion, a commonly used dispersion aid such as a water-soluble organic solvent or a surfactant may be used in combination. It is desirable that the aqueous dispersion be sufficiently fluid under stirring.

In the present invention, examples of water-soluble compounds of metal compounds include inorganic acid salts such as nitrates, hydrochlorides and cyanides, and organic acid salts such as oxalates. An aqueous solution is obtained by dissolving a water-soluble compound of these metal compounds in water. In addition, for example, by adding a hydrolyzing agent such as alkali hydroxide, ammonia, ethylenediaminetetraacetic acid and its alkali salt, a chelating agent, etc. to an aqueous solution of a metal compound, the metal compound is precipitated as a fine colloid and homogeneous. An aqueous dispersion containing a metal compound is obtained.

In the present invention, the reducing agent is a substance that reduces a metal compound by itself or in the presence of a reducing catalyst.
Examples thereof include formaldehyde, sodium thiosulfate, tartaric acid and salts thereof, hydrazine and salts thereof, hydrogen peroxide, barium peroxide, calcium peroxide and the like, which exhibit a reducing property in the presence of an alkali. Examples of the reducing catalyst include alkali metal compounds such as sodium hydroxide and potassium hydroxide against peroxides.

In the present invention, the use ratio of the metal compound and the reducing agent is not particularly limited as long as it is at least the stoichiometric amount necessary for the reduction of the metal compound, but it is usually preferable to use the reducing agent in an excessive amount.

It is preferable that these reduction reactions are always carried out in a homogeneous dispersion system. If the dispersion is insufficient, the coating material tends to be inhomogeneous. These reduction reactions can be carried out near room temperature, but are preferably carried out at 10 to 40 ° C. if the reaction is exothermic, and at 20 to 50 ° C. if the reaction is not exothermic. In any case, when the temperature is higher than 70 ° C., the reaction becomes too rapid and the surface becomes inhomogeneous. On the contrary, when the temperature is lower than 0 ° C., the reaction becomes slow and productivity is deteriorated.

[0023]

According to the present invention, the metal adhesion amount is reduced, the specific gravity is reduced, and the conductivity of the highly conductive composition is reduced to 1
It is possible to provide a highly conductive substance applicable to a field requiring a high electrical conductivity of 0 ⁻³ to 10 ⁴ Ω · cm. The highly conductive substance of the present invention requires conductivity such as a conductive material, a charging material, an antistatic material, and an electromagnetic wave shielding material in the fields of ink, paint, sheet moldings, films, fibers, molded products and the like. It is suitable for the material.

[0024]

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

Example 1 White conductive potassium titanate fiber (Dentol WK-2
00B, manufactured by Otsuka Chemical Co., Ltd. 3g homogeneously dispersed in 100ml water, 1.6g silver nitrate was dissolved in 50ml water, then 3.3ml ammonia water (concentration 28%) was homogeneously dissolved, and silver nitrate was added. A dispersion liquid in which was dissolved was obtained. Then, separately adjusted potassium sodium tartrate 11.4
g dissolved in 100 ml of water, 0.24 g of silver nitrate
Was dissolved in 10 ml of water, and a reducing solution in which silver was colloidally dispersed in an aqueous solution was stirred at a reaction temperature of 30-
It takes 30 minutes while maintaining the temperature at 40 ° C., and after adding to the white conductive potassium titanate fiber dispersion liquid, the mixture is stirred for 30 minutes.
After aging for a minute, the precipitate was filtered off and dried to obtain 4.1 g of a gray-brown highly conductive substance in which the surface of the white conductive potassium titanate fiber was coated with silver. The volume resistivity is
The specific gravity was 7.0 × 10 ⁻³ Ω · cm and 6.0.

Example 2 In 400 ml of a 0.2 molar aqueous solution of ethylenediaminetetraacetic acid disodium salt, 20 g of silver nitrate was added under stirring to 1 part of water.
A solution dissolved in 00 ml was added, and a part of silver nitrate was chelated to obtain a colloidal dispersion. 78 g of white conductive potassium titanate fiber was added to water 1500
In addition to the dispersion in 30 ml, 200 ml of 30% hydrogen peroxide was further added to the dispersion. The above dispersion is stirred for 10
200 ml of 5N aqueous sodium hydroxide solution was added dropwise to the solution at -15 ° C on an ice-water bath over about 60 minutes, and the temperature was adjusted to 10-1.
While keeping the temperature at 5 ° C, add 30 ml of 30% hydrogen peroxide water to 30 ml.
The reaction mixture was added dropwise over a period of time, filtered, and dried to give 90.6 g of a grayish brown highly conductive substance having a volume resistivity of 3.5 × 10 ⁻¹ Ω · cm and a specific gravity of 5.2. Obtained.

Example 3 White conductive potassium titanate fiber 1 in Example 1
The same operation was performed except that 8.3 g was uniformly dispersed in 400 ml of water, and the volume specific resistance was 2.5 × 10 ⁰ Ω · cm.
Thus, 19.3 g of an off-white brown highly conductive substance having a specific gravity of 4.7 was obtained.

Example 4 White conductive titanium oxide (W-1, Mitsubishi Materials Corp.)
(13.1 g) was uniformly dispersed in 300 ml of 4N hydrochloric acid, 1 ml of 80% hydrazine hydrate was added, and 40 g of a 10% hydrochloric acid aqueous solution of chloroauric acid was added under stirring to a dispersion containing a metal compound. A liquid was obtained. It takes about 30 minutes under stirring while adjusting the above-mentioned dispersion liquid on an ice-water bath so that the reaction temperature does not exceed 30 ° C., and 100% of 80% hydrazine hydrate is added.
After dripping 1, the mixture was aged at 30 ° C. for 2 hours, filtered, and dried to give a surface with gold-covered volume resistivity 2.0 × 1.
Gray-red highly conductive substance with a specific gravity of 6.9 at 0 ^-1 Ω · cm 1
5.3 g was obtained.

Example 5 Using white conductive needle-shaped titanium oxide (FT1000, manufactured by Ishihara Sangyo Co., Ltd.), copper sulfate 35 g / l, Rossell salt 17
0 g / l, caustic soda 50 g / l, sodium carbonate 30 g /
1 and an aqueous solution consisting of EDTA 20 ml / l,
After adding 20 g of 37% pure formalin, 55.7 g of a conductive substance was added, the mixture was stirred at room temperature for 3 minutes, and then filtered,
Washed with water and dried. As a result, 69.5 g of a highly conductive substance having a volume resistivity of 7.3 × 10 ⁻² Ω · cm and a specific gravity of 5.4, the surface of which was covered with copper, was obtained.

Example 6 White conductive mica (MEC-500, Teikoku Kako Co., Ltd.)
Made of nickel sulfate 40 g / l, sodium citrate 25 g / l, sodium hypophosphite 20 g / l, sodium acetate 5 g / l and ammonium chloride 5 g / l, and a conductive substance 48.1 g. The same treatment as in Example 5 was carried out except that the high-conductivity material 63 having a volume resistivity of 5.1 × 10 ⁻² Ω · cm and a specific gravity of 4.7, the surface of which was covered with metallic nickel. 0.1 g was obtained.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C23C 18/44 H01B 1/08 7244-5G

Claims (1)

[Claims] 1. A Pt, Au, Ru, Rh, Pd, Ni, Co layer on the surface of a tin oxide / antimony oxide conductive material.
A highly conductive substance, which is provided with an adhesion layer of at least one metal selected from the group consisting of Cu, Cr, Sn and Ag.