JPH0517148A - Fibrous black conductive substance and production thereof - Google Patents

Abstract

PURPOSE:To produce a fibrous black conductive substance by forming a film of either one of partially reduced substance of tin oxide or titanium oxide or a compound film thereof on the surface of a fibrous titanium oxide or fibrous alkali titanate. CONSTITUTION:Fine particles of fibrous titanium oxide or fibrous alkali titanate is dispersed into a solution consisting of SnCl4 (or TiCl4), organic polybasic acid, HC1 and water and the above-mentioned SnCl4 or TiCl4 are hydrolyzed by heating the dispersion and the deposited ultra-fine particles of Sn salt or Ti salt of organic polybasic acid are applied in a form of a film to the surface of fine particles of the above-mentioned fibrous titanium oxide or fibrous alkali titanate and then the film is calcined at 700-1000 deg.C in the presence of N2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fibrous black conductive material and a method for producing the same.

[0002]

2. Description of the Related Art It has been proposed in the past to use an alkali titanate as a powder material for adding conductivity to plastics, paints, etc., and treating and processing this into conductive powder. There is. For example, by mixing alkali titanate itself with a carbon material, the temperature of inert gas (500
~ 1300 ° C) firing method (Japanese Patent Publication No. 62-3767)
Japanese Patent Publication No. 62-40291, etc.) are known. Since this method is carried out by physically mixing carbon substances, there is a drawback that the fiber shape of alkali titanate is easily broken or granulated by external force at this time, and finally, a high conductivity value ≒ powder volume electric It is difficult to expect a specific resistance value. In addition, the alkali titanate itself is used under high temperature of hydrogen gas (500
C. to 1100.degree. C.) to produce a white electroconductive alkali titanate partially reduced product (JP-A-60-11261).
No. 7) is also proposed, but handling of hydrogen gas requires measures for safe work, and it is particularly necessary to deal with safety in terms of equipment. Further, in the hydrogen reduction by this method, permeation of hydrogen gas into the alkali titanate powder requires a long time at a high temperature, which is not preferable in terms of production efficiency. Also known is a method (Japanese Patent Laid-Open No. 63-12758) of obtaining a conductive fiber substance under an inert or reducing atmosphere by drying a fiber substance dispersed in a hydrocarbon solution and drying it. Although the use of alkali titanate fibers is disclosed, this case also has the same problems as described above for alkali titanate fibers.

[0003]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention As a result of earnest research to solve the above-mentioned problems of the prior art, the present inventor has found that
The surface of each of the fibrous titanium oxide or the fibrous alkali titanate particles is coated with a tin oxide partial reductant (SnO _2-x ) or a mixture thereof with carbon, or a titanium oxide partial reductant (TiO _{2- The} present invention has been completed based on the finding that one coated with either _x ) or a coating consisting of a mixture of carbon and carbon or a composite coating thereof (two-layer structure) has excellent conductivity. . An object of the present invention is to provide such a conductive material and a method for efficiently manufacturing the same.

[0004]

The fibrous black conductive material of the present invention has a surface of fine fibrous titanium oxide particles or fine fibrous alkali titanate particles to achieve the above object.
Forming a single coating or a composite coating layer of either a tin oxide partially reduced product or a film made of a mixture of carbon and tin, or a titanium oxide partially reduced product or a film made of a mixture of carbon and titanium. It is a characteristic black fibrous conductive material. In addition, a method for producing such a conductive substance is such that a surface of fibrous titanium oxide fine particles or fibrous alkali titanate is coated with a coating layer of a tin salt or titanate of an organic polybasic acid, or a coating layer including these two layers. After coating with a layer, this is treated under an inert gas atmosphere at 300-1000.
It is characterized by calcination at ℃.

The fibrous titanium oxide or alkali titanate (hereinafter referred to as a substrate) used in the present invention usually has an average length of about 40 μm and an aspect ratio of about 80. On the surface of each such particle, first, an organic polybasic acid such as tartaric acid,
To coat with tin or titanium salts such as succinic acid, malic acid, and citric acid, (SnCl ₄ + organic polybasic acid) or (Ti
Cl ₄ + organic polybasic acid) is dispersed individually in an aqueous solution of Cl ₄ + organic polybasic acid so as not to cause aggregation, and the dispersed solution is gradually heated to hydrolyze the SnCl ₄ or TiCl ₄ and precipitate. Ultrafine particles of Sn salt or Ti salt of organic polybasic acid are deposited and coated in the form of a film on the surface of the base particles while supporting the dispersion of individual base particles. The dispersion concentration of the substrate at this time is usually preferably 0.5 to 5%. The amount (weight ratio) of SnCl ₄ or TiCl ₄ used is SnCl ₄ or Ti
Cl ₄ /substrate=0.01 to ₄ is preferable. The amount (molar ratio) of organic polybasic acid used is organic polybasic acid / SnCl ₄ or T
iCl ₄ = 0.2-5 is preferred. In addition, the above-mentioned hydrolysis is usually carried out at 50 to 100 ° C. for 1 to 10 hours.

The substrate coated with the tin or titanium salt film of the organic polybasic acid in this way is filtered and washed with water by a conventional method.
By drying with hot air at 0 to 120 ° C., a good white powder state that does not require an external pulverizing step is obtained. The powder obtained is usually calcined in a tubular electric furnace at 300 to 600 ° C. while passing an inert gas such as N ₂ gas, and the tin salt film or titanium salt of polybasic acid on the particle surface is usually used. The film or these two-layer film is thermally decomposed to a carbon (C) -containing “SnO ₂ + carbon” film or “TiO ₂ + carbon” film or these two-layer film, but the calcination temperature is further 700
Carbon (C) in the film by raising the temperature to ~ 1000 ° C
Is deoxidatively partially reduced to oxygen (O ₂ ) of SnO ₂ or TiO ₂ as follows, SnO ₂ (or TiO ₂ ) + C → SnO _2−x (or TiO _2−x ) + CO ₂ black A conductive SnO _2-x film or TiO _2-x film is formed, and a fibrous black conductive substance based on fibrous titanium oxide or alkali titanate having excellent conductivity is obtained.

Looking at the electrical conductivity of the obtained product in terms of powder volume electrical resistivity, (conductive film amount ≈ SnO _2-x or Ti
O _2-x or their mixture amount) and (the amount of fibrous titanium oxide or fibrous alkali acid titanate) increase,
Although the conductivity is improved from 10 ¹⁰ Ωcm to 10 ^-1 Ω, the preferable ratio of the "conductive film amount" to the "fibrous titanium oxide or fibrous alkali titanate amount" is 0.05 to 2.0. .

[0008]

[Function] To form a conductive film on the surface of the fibrous titanium oxide fine particles or the fibrous alkali titanate fine particles, first, a tin salt or titanium salt film of an organic polybasic acid is formed, and then this is calcined. As a result, carbon is generated in the film by thermal decomposition at the initial stage of calcination, and then the generated carbon causes the partial deoxidative reduction of SnO ₂ or TiO ₂ in the film, so that the reduction is extremely effective. Is carried out.
In addition, the conductivity value of the powder volume electric resistance is about 10 ^-1 Ω, which is very good. Therefore,
For example, it is suitable as a conductive filler for plastics, paper, paints and the like, and the compounding amount can be reduced.

[0009]

Example 1 Tin chloride (SnCl ₄ ) 8.65 g Malic acid 4.45 g 35% HCl 20 ml Deionized water 1000 ml With stirring, the solution (A) was stirred to form a fibrous material having an average length of 40 μm and an aspect ratio of about 80. Titanium oxide 50 g 35% HCl 10 ml Deionized water 3500 ml Suspension (B) was gradually added to bring the total amount to about 450.
It was set to 0 ml. After that, the dispersion suspension under stirring was gradually heated and heated, and when it reached 60 ° C., titanium chloride (TiCl ₄ ) 106.9 g Malic acid 75.6 g 35% HCl 25 ml Deionized water 500 ml Solution (C) is gradually added, and at the same time, the temperature of the solution system is gradually increased to hydrolyze SnCl ₄ and TiCl ₄ to precipitate "Sn salt of malic acid and Ti.
The “ultrafine particles of salt” are film-coated on the surface of the fibrous titanium oxide particles that are effectively dispersed in this solution system. When the temperature of this solution system reaches 95 ° C., heating is stopped, and the wet cake obtained by filtering and washing this with a conventional method is dried with hot air at 100 ° C., so that external force pulverization is not necessary. It becomes a very good white powder. Take this in an alumina porcelain boat, place it in an inert gas (N ₂ ) substituted tubular electric furnace, and calcine 800 ° C x 1 hr while gradually increasing the temperature inside the furnace while passing N _2. Thus, a fibrous titanium oxide coated with a two-layer coating composed of a black conductive reduction coating SnO _2-x and TiO _2-x was obtained. The powder state of this powder was very good, and the volume electrical resistivity of the powder was 7 × 10 ^-1 Ωcm 2. The volume electric resistivity of the powder was measured according to the following procedure. A cylindrical powder compact having a diameter of 20 mm and a thickness of 4 mm was molded from the conductive powder under a pressure of 100 kg / cm ² , and the volume electrical resistivity of this was measured.

[0010]

Comparative Example 1 In Example 1, malic acid and 35% H
Except for not using Cl, SnC
I ₄ and TiCl ₄ were hydrolyzed, but the fibrous titanium oxide particles in this system were not dispersed individually, but were a stirring system in which they were aggregated with each other. Further, in the filtering operation after the completion of hydrolysis, the filterability is very poor, and the product dried with hot air at 100 ° C. becomes a white cracked solid,
It was not very powdery. Further, this was placed in an alumina porcelain boat as in Example 1 and allowed to stand in an inert gas (N ₂ ) substituted tubular electric furnace, and the furnace temperature was gradually raised while passing N ₂ gas to 800 It was calcined at 1 ° C. for 1 hour, but the obtained product was still a white rice cracker-like solid and the conductivity was 10 ¹⁰ Ω or more, which was unmeasurable.

[0011]

Example 2 Instead of fibrous titanium oxide in Example 1, potassium titanate “K ₂ O (TiO ₂ ) ₆ ” having an average length of 40 μm and an aspect ratio of about 80 and apple as the organic polybasic acid in Example 1 were used. The same procedure was carried out except that tartaric acid was used in the same molar amount instead of the acid. The obtained fibrous black conductive material was in a good powder state, and the powder volume electric resistivity was 1 × 10 ⁻¹ Ω.

[0012]

Example 3 The fibrous black conductive material obtained in the same manner as in Example 2 except that the same molar amount of citric acid was used instead of tartaric acid as the organic polybasic acid was good. It was in a powder state and the powder volume electric resistivity was 4 × 10 ⁻¹ Ω.

[0013]

Example 4 Titanium chloride (TiCl ₄ ) 11.9 g Citric acid 12.0 g 35% HCl 20 ml Deionized water 1000 ml While stirring, a fibrous material having an average length of 40 μm and an aspect ratio of about 80 Titanium oxide 100 g 35% HCl 20 ml Deionized water 3500 ml A suspension (E) was gradually added to bring the total amount to about 450.
It was set to 0 ml. Thereafter, the suspension dispersion liquid under stirring was gradually heated and heated, and when it reached 70 ° C., titanium chloride (TiCl ₄ ) 106.9 g citric acid 107.7 g 35% HCl 25 ml deionized water 500 ml Solution (F) is gradually added, and at the same time, the temperature of the hydrolysis system is also gradually increased to hydrolyze and precipitate TiCl ₄ "ultrafine particles of Ti salt of citric acid". The surface of the fibrous titanium oxide particles effectively dispersed inside is coated in a film-like manner. The temperature of this solution system is 95
When the temperature reaches ℃, the heating is stopped and this is filtered by a conventional method.
When the wet cake obtained by washing with water is dried with hot air at 80 ° C., it becomes a very good white powder that does not require external pulverization. This is subjected to thermal decomposition to deoxidation reduction under the same calcination conditions as in Example 1 to obtain a black conductive reduction film T.
A fibrous titanium oxide coated with a film of iO _2-x was obtained. The powder state of this product was very good, the volume electric resistivity of the powder was 9 × 10 ⁻¹ Ωcm, and the yield composition of the powder was fibrous titanium oxide 100 g deoxidation reduction (TiO _2-x ). It was 40 g.

[0014]

Comparative Example 2 Instead of citric acid as the organic polybasic acid in Example 4, acetic acid (CH ₃ COO) which is an organic monobasic acid was used.
Hydrolysis of TiCl ₄ was carried out by the same procedure except that the same molar amount of H) was used, but the particles of fibrous titanium oxide in this system were not dispersed individually but coagulated with each other. It was a stirring system. Further, in the filtration operation after the completion of hydrolysis, the filterability was very poor, and the product dried with hot air at 80 ° C. became a white rice cracker-like solid, which was not very powdery. Further, this was calcined under the same calcining conditions as in Example 4, but it was also a white rice cracker-shaped solid and the conductivity was 10 ¹⁰ Ω or more, which was not measurable.

[0015]

Example 5 The hue of each fibrous black substance powder obtained by the same operation as in Example 4 except that the calcination temperature in Example 4 was the temperature shown in Table 1, the presence or absence of carbon inclusion, The powder volume electric specific resistance was as shown in Table 1, respectively.

[0016]

[Table 1]

[0017]

Industrial Applicability The fibrous black conductive material of the present invention comprises a partially reduced form of tin oxide (SnO _2-x ) or a mixture of carbon with the surface of the particles of fibrous titanium oxide or fibrous alkali titanate. The powder volume electric resistivity has excellent conductivity by being coated with a film made of titanium oxide, a film made of a partially reduced form of titanium oxide (TiO2 _-x ), a film made of a mixture of carbon and carbon, or a double-layered film of these. Therefore, it is suitable as a filler for imparting conductivity to plastics, paper, paints and the like. Moreover, the effect is extremely large because it can be manufactured safely and efficiently.

Claims (3)

[Claims] 1. A film comprising a partially reduced form of tin oxide or a mixture thereof with carbon, or a partially reduced form of titanium oxide or with this and carbon, on the surface of the fine particles of fibrous titanium oxide or the fine particles of fibrous alkali titanate. A fibrous black conductive substance, characterized in that a single film of a mixture or a composite film layer thereof is formed. 2. The surface of the fibrous titanium oxide fine particles or the fibrous alkali titanate is coated with a coating layer of a tin salt of an organic polybasic acid or a titanate or a coating layer consisting of these two layers, and then the coating layer is not coated. 300 to 1000 in an atmosphere of active gas
A method for producing a fibrous black conductive material, which comprises calcination at ℃. 3. The method for producing a fibrous black conductive substance according to claim 2, wherein the organic polybasic acid is tartaric acid, succinic acid, malic acid or citric acid.