JPH06183733A - Electric conductive white powder and it production - Google Patents

Abstract

PURPOSE:To obtain an electric conductive fine powder having high whiteness, a controlled hue and satisfactory dispersibility by incorporating specified amts. of Al, P, Mo, W, antimony oxide and tin oxide. CONSTITUTION:A water-soluble tin compd. is mixed with 1-30wt.% (expressed in terms of antimony oxide) water-soluble antimony compd. and an aq. soln. of the mixture acidified with hydrochloric acid or an alkaline aq. soln. of the mixture is prepd. One or more of compds. of Al, P, Mo and W as third elements are dissolved in the aq. soln. so as to attain 0.1-7wt.% content (expressed in terms of oxides) and hydrolysis is carried out to obtain antimony-tin hydrate contg. the third elements. This hydrate is washed, separated by filtration, dried, fired at 300-700 deg.C and pulverized to produce the objective electric conductive white powder consisting of 0.1-7wt.%, in total, of one or more from among Al, P, Mo and W, 3-30wt.% antimony oxide and the balance tin oxide and having <=0.2mum average particle diameter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved antimony oxide-containing tin oxide white conductive fine powder and a method for producing the same. More specifically, it relates to a method for producing tin oxide fine powder containing antimony oxide as a filler for forming a colorless and transparent conductive coating film having no tint. Ceramics in which antimony oxide-doped tin oxide powder is doped with antimony oxide are 1 to 7
It is widely used as a conductive powder having good conductivity with a specific resistance of 0 Ω · cm and not being affected by humidity. Among them, it is filled in resin to give conductivity to molded products and coating films, and is used as antistatic transparent film for recording films and magneto-optical disks, semiconductor clean room panels, etc., and also used for catalysts, sensors, etc. Has been done.

[0002]

2. Description of the Related Art When using a tin oxide powder containing antimony oxide as a filler to form a transparent conductive sheet,
Since it forms a thin film of 5 μm, the particle size is 0.2 μm or less (preferably 0.1 μm or less), which is half the wavelength of visible light.
It must be fine, uniform, and excellent in dispersibility and conductivity. Further, generally, in order to impart good conductivity to tin oxide, antimony oxide is added (doped), but the addition amount is generally in the range of 1 to 30% by weight, preferably 5 to 20% by weight as antimony oxide. However, as the amount of dope increases, the tint of the powder tends to increase, and the tint is suppressed from the viewpoint of the use characteristics and appearance of the transparent conductive sheet, and it becomes colorless (whitened) or close to it. It is desirable to be a thing.

The production of Sn (IV) ions and Sb
(III) Ion-containing aqueous solution, generally obtained by neutralizing and coprecipitating from an acidic hydrochloric acid solution of stannic chloride (SnCl ₄ ) and stannous antimony (SbCl ₃ ) by adding an alkaline solution After washing the hydroxide precipitate with water, the solid-liquid is separated, dried and fired. For drying and firing, the precipitate is transferred to a tray and heated in a batch type heating furnace, or placed on a conveyor and heated by a continuous heating device. After cooling, it is generally pulverized into powder and then sifted.

As a method for producing tin oxide fine powder with suppressed tint, for example, in Japanese Examined Patent Publication No. 62-1574, a tin chloride solution is added to this solution while keeping an alkaline aqueous solution having a pH of 10 or more at 65 ° C. or more to cause precipitation. A fine precipitate is obtained by finally producing it and maintaining it at pH 5 to 1, washing it, drying it, and then 350 to 700 ° C. in a reducing atmosphere or an inert atmosphere.
There is disclosed a method for producing a tin oxide fine powder having a low electric resistance, which comprises firing at a temperature of. However, although the tin oxide fine powder produced by this method has a good tint, it is difficult to obtain a low resistance powder having an electrical conductivity of 100 Ω · cm or less, and further, it lacks oxidative stability depending on the degree of reduction. There was a problem.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art, and to provide a conductive fine powder having high whiteness, suppressed tint and good dispersion. As a result of earnest studies to achieve the above object, the present inventors have found that the problem can be solved by adding aluminum, phosphorus, molybdenum, and tungsten as the third element to antimony oxide-doped tin oxide.

[0006]

Structure of the invention and reason for limitation In the present invention, the total amount of aluminum, phosphorus, molybdenum and tungsten is 0.1 to 7 w.
Provided is a white conductive powder containing t%, antimony oxide in an amount of 3 to 30 wt%, and the balance being tin oxide and having a particle size of 0.2 μm or less.

The present invention also provides a water-soluble aluminum compound, a phosphorus compound, in a production method of mixing a water-soluble tin compound and an antimony compound coexisting mixed aqueous solution and an alkaline aqueous solution to neutralize and precipitate a hydroxide. A compound, a molybdenum compound, or a tungsten compound, which is mixed to precipitate a hydroxide, and the hydroxide is washed, dried, fired, and pulverized to obtain an antimony oxide-containing tin oxide having an average particle diameter of 0.2 μm or less. A method for producing a fine powder is provided.

In the present invention, the water-soluble compound means a salt of a metal and an oxyacid containing a metal in an acid radical or a salt thereof. The amount of antimony oxide added is 1 to 30 wt% and is 1
If it is less than wt%, the tint is reduced, but the conductivity is insufficient. Further, even if it exceeds 30 wt%, the conductivity does not change and the blue tint increases. Aluminum, phosphorus, molybdenum, and tungsten added as the third element are 0.1 to 0.1 as oxides.
7 wt%, preferably 0.3 to 3 wt%, 0.1 w
If it is less than t%, no improvement in color and whiteness is observed, and 7 wt%
Even if it exceeds, the conductivity does not decrease. As a method of adding the third element, a compound of aluminum, phosphorus, molybdenum and tungsten is dissolved in a tin-antimony mixed hydrochloric acid acidic aqueous solution or an alkaline aqueous solution. Examples of the compound added to the tin-antimony mixed hydrochloric acid aqueous solution include aluminum chloride, aluminum nitrate, aluminum sulfate, phosphoric acid, molybdic acid, molybdenum pentachloride, tungstophosphoric acid, and tungsten hexachloride.
Examples of compounds added to the alkaline aqueous solution include aluminate (sodium aluminate), phosphate (sodium hexametaphosphate, etc.), molybdate (sodium molybdate, etc.), and tungstate (sodium tungstate, etc.). To be The solution containing these compounds is hydrolyzed to obtain antimony tin hydrate containing the third element. As a raw material of tin oxide and antimony oxide, there are chlorides, organic compounds (alkoxides) and the like, but chlorides are preferable.

Specifically, the method of the present invention comprises tin chloride,
When a tin hydrate precipitate containing antimony hydrate is obtained by reacting a mixed hydrochloric acid aqueous solution of antimony chloride with an alkaline aqueous solution, an aluminum compound, a phosphorus compound, a molybdenum compound, or a tungsten compound is previously added to the tin antimony mixed hydrochloric acid aqueous solution or the alkaline aqueous solution. Of at least one of them is dissolved and hydrolyzed, washed with water, separated by filtration, dried, and fired (300 ° C. to 700 ° C., preferably 450 ° C. to 650 ° C.) to obtain conductivity. Examples of the alkaline aqueous solution used for hydrolysis include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate, carbonates and ammonia.

DETAILED DESCRIPTION OF THE INVENTION The present invention will be specifically described below with reference to specific examples.

[0010]

Example 1 2 l of water was stirred and kept at 90 ° C., and 200 ml of an acidic hydrochloric acid aqueous solution containing 90 g of stannic chloride and 8 g of antimony trichloride and 2 g of sodium hexametaphosphate were dissolved in the sodium hydroxide aqueous solution (500 g /
l) 200 ml was simultaneously added dropwise over 30 minutes to obtain antimony tin hydrate containing phosphorus. It was washed with water, filtered, dried (100 ° C.), and then baked (600 ° C., 1 hr). Obtained 58 g of powder (antimony oxide 10 wt
%, Phosphorus 1 wt%) has a specific surface area of 76 m ² / g (average particle size 0.02 μm), and the color tone was measured to find an L value of 65, a
-2.0, b-2.3 (color computer manufactured by Suga Test Instruments Co., Ltd.), volume resistance value 5 Ω · cm (100 kg / cm
² pressurized powder).

Example 2 1.4 g of sodium aluminate was dissolved in an aqueous sodium hydroxide solution, and conductive fine powder was synthesized in the same manner as in Example 1. The obtained 57 g of powder (antimony oxide 10 wt%, aluminum 0.8 wt%) has a specific surface area of 91 m ² / g (average particle size 0.015 μm), color tone L value of 60, a-3.1, b-2.6. , Volume resistance value 6Ω
・ It was cm.

Example 3 3.7 g of sodium molybdate was dissolved in an aqueous sodium hydroxide solution, and conductive fine powder was synthesized in the same manner as in Example 1. The obtained 57 g of powder (antimony oxide 10 wt%, molybdenum 2.5 wt%, specific surface area 109 m ² / g (average particle size 0.015 μm), color tone L value 61, a −2.1, b −0.8, Volume resistance value 2Ω
・ It was cm.

Comparative Example 1 A conductive powder was synthesized in the same manner as in Example 1 without adding the third element. The obtained 57 g of powder (antimony oxide 10 wt%) has a specific surface area of 60 m ² / g.
(Average particle size 0.02 μm), color tone L value 38, a −4.
6, b-8.3, and the volume resistance value was 2 Ω · cm.

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[Procedure amendment]

[Submission date] October 13, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Title of invention

[Correction method] Change

[Correction content]

Title: Conductive white powder and method for producing the same

Claims (2)

[Claims] 1. A white electroconductive material containing 0.1 to 7 wt% of aluminum, phosphorus, molybdenum, and tungsten in total, 3 to 30 wt% of antimony oxide, and the balance being tin oxide, having an average particle size of 0.2 μm or less. Powder. 2. A water-soluble aluminum compound, phosphorus compound, molybdenum, which is used in a production method in which a mixed aqueous solution in which a water-soluble tin compound and a water-soluble antimony compound coexist and an alkaline aqueous solution are mixed and neutralized to precipitate a hydroxide. After mixing at least one of the compound and the tungsten compound to precipitate the hydroxide, the hydroxide is washed, dried, and calcined,
A method for producing a white conductive powder, which is pulverized to obtain a tin oxide fine powder containing antimony oxide having an average particle diameter of 0.2 μm or less.