JPH03150302A - Fibrous copper powder and manufacture thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a novel fine fibrous copper powder that can be used as a conductive paste material, a material to be mixed with a resin and injection molded, and a method for producing the same.

[Conventional technology]

Conventional methods for producing copper powder include a method of reducing charcoal, copper sulfate, and hydroxide steel without water, as well as an atomization method. However, the copper powder obtained by these methods is granular and not fibrous.

There is an electrolytic method for obtaining fibrous copper powder, but although the copper powder obtained by this method is fibrous, it is large, several tens of micrometers, and non-uniform.

For this reason, fibrous copper powder with a small particle size that can be used to produce products with high packing density as superconducting paste materials or injection molding materials has not yet been provided.

[-Problem to be solved by the invention]

The present invention aims to provide a novel fibrous copper powder and a method for producing the same in response to the current situation.

[Means to solve the problem]

The present invention has a long axis of 1 to 15 μm and an aspect ratio of 5 to 2.
A solution containing the fibrous copper powder (No. 5) and copper ions is reacted with ammonium ions in an amount equivalent to or more than the copper ions in the solution to form copper ammonium complex ions, and then the temperature of the solution is raised to 80 C. "A fibrous steel is produced by reacting an equivalent or more amount of caustic alkali with copper ions to obtain hydroxide steel, and heating the hydroxide steel to 150 to 450C in a reducing atmosphere to reduce it to copper. It is in the manufacturing method of copper powder.

In the method of the present invention, the steel ions in the solution containing copper ions include chlorinated steel, water-soluble abrasive salts such as sulfuric acid #1, and basic carbonated steel that reacts with ammonium ions to form steel ammonium complex ions. If the concentration of copper ions in the aqueous solution is too low, productivity will decrease, so the concentration is 10 g/
It is preferable that the number is 1 or more.

Ammonium ions include ammonium chloride, ammonia, and ammonia water, but ammonia or ammonia water is preferable in order to prevent contamination with impurities.

(Function) In the method of the present invention, copper ions are converted to steel ammonium complex ions.When hydroxide is converted to m with caustic alkali, columnar crystal hydroxide steel is obtained by passing through copper ammonium complex ions. This is to ensure that By first converting copper ammonium complex ions into copper ammonium complex ions and then adding caustic alkali to form hydroxide steel, the present invention does not form a gel-like state as in the case where caustic alkali is added directly to copper ions, but has a sedimentation property. It was discovered that fibrous hydroxide with good filterability can be obtained.

Converting copper ions to copper ammonium complex ions The amount of ammonium ions added must be at least equivalent to the copper ions in the aqueous solution in order to convert all the copper ions in the aqueous solution to copper ammonium complex ions. If the amount is less than the equivalent amount, gel-like hydroxide steel will be produced when caustic alkali is added subsequently, resulting in poor sedimentation and filterability. Furthermore, even if ammonium ions are added in large excess, the effect remains unchanged and it is uneconomical.

Caustic alkali is most suitable for precipitating copper hydroxide by adding an alkali to a solution in which copper ammonium complex ions have been generated, considering the strength of the alkali. Although this reaction proceeds satisfactorily at room temperature, it is better to heat the solution to increase the reaction rate; however, if the liquid temperature is too high, the oxidized steel will precipitate, making it impossible to obtain columnar crystal hydroxide steel. ,
It is desirable that the temperature be 80 C or less, preferably 60 C or less.

When the hydroxide steel obtained in this way is separated from the liquid, washed, dried, and then heated and reduced in a reducing atmosphere, fine fibrous copper powder is obtained, but if the reduction temperature is low, water Oxidized steel remains and if the temperature is too high, sintering will occur and fibrous copper powder will not be obtained. Therefore, it is desirable to set the heating temperature to 150 to 450 C, preferably 200 to 300 C. The heating time depends on the equipment and Since it varies depending on the conditions, it is best to find the optimal time according to the equipment and conditions in advance through testing.

When copper powder is produced in this manner, a fibrous powder having a major axis of 1 to 15 μm and an aspect ratio of 5 to 25 can be obtained. Copper powder smaller than this tends to aggregate and has poor dispersibility when mixed with other materials, whereas the fibrous copper powder of the present invention has good dispersibility and does not aggregate. It can be mixed easily and evenly with powder raw materials, and can be used to form paste materials for forming conductive films with a high packing density that is thick and resistant to wear, and can be mixed with resins to form high-density materials.

〔Example〕

Example 1 1750 g of 0u30・5H0 was dissolved in 4.21 g of pure water, and 2.5 g of aqueous ammonia was added to this solution while stirring.
8j In addition, copper in the liquid was converted into copper ammonia complex ions.

Next, the liquid was heated to 60 C" while stirring, and the liquid temperature was increased to 60 C".
To maintain C, 200 get of the liaOH solution, equivalent to the copper in the solution, was added over 20 minutes using a roller pump. After stirring for about 30 minutes to complete the reaction, the resulting precipitate was filtered off and the pulp was washed three times with pure water. Washed precipitate 6
Drying at 0 C yielded 607 g of columnar copper precipitate. This precipitate was reduced by heating at 250C for 3 hours in a hydrogen stream to obtain 375 g of copper powder. The yield was 84.2%. When this copper powder was observed with an electron microscope, the minor axis was 0.
It was a fibrous copper powder having a shape shown in the drawing with a length of 5 to 0.7 μm and a major axis of 7 to 10 μm.

Example 2 Cu (Fj 67.4 g was dissolved in 300-g of water,
25% ammonia water 424- was added to this solution while stirring to convert the copper ions in the solution into copper-ammonium complex ions.

This solution was heated to a temperature of 55 C" while stirring. Next, a roller pump was used to maintain the liquid temperature at around 60 C" so that the amount of copper in the solution was 2.1 equivalents. 200 gel of NaOH solution 424- was added over 3θ minutes. In order to complete the reaction, the mixture was stirred for an additional 30 minutes, and the resulting precipitate was filtered off and washed three times with pure water. This precipitate was dried at 65 C" to obtain 45.8 g of columnar copper precipitate. This precipitate was dried at 250 C in a hydrogen stream.
The mixture was heated for 3 hours for reduction, and 28.6 g of copper powder was obtained. The yield was 89.6%.

When this copper powder was observed by electron microcasting, the short diameter was 0.4 to 0.
．． It was a fibrous copper powder with a length of 7 μm and a length of 6 to 8 μm.

Example 3 Basic copper carbonate (OuCO.Cu (OH) -HO)
61.2 g was suspended in 612 gLt of water, and 25% aqueous ammonia was added to the souffle with stirring to convert the copper in the liquid into copper ammonia complex ions. Next, this liquid was heated while stirring to bring the liquid temperature to 60 C''.

Then, 200 g equivalent to 1 g for the copper in the solution.
gel(F) NaOHW t&424- was added using a roller pump over 17 minutes so that the liquid temperature was maintained at around 60C. After stirring for about 30 minutes to complete the reaction, the resulting precipitate was filtered off and the pulp was washed three times with pure water. The washed precipitate was dried at 60 C" to obtain 45.6 g of columnar copper precipitate. This precipitate was heated at 250 C for 2 hours in a hydrogen stream to reduce the
8.5 g of copper powder was obtained. The yield was 87.8%. When this copper powder was observed with an electron microscope, the minor axis was 0.4 to 0.
．． It was a fibrous copper powder with a length of 6 μm and a major axis of 6 to 8 μm.

〔Effect of the invention〕

According to the present invention, the major axis is 1-15 μm, the aspect ratio is 5-15 μm, and the aspect ratio is 5-15 μm.
25 novel conductive films with good dispersibility and high packing density,
It is possible to provide a fibrous copper powder that can be used to produce resin molded products and a method for producing the same.

A simple explanatory drawing of the Buddhist altar surface is a 3500x electron micrograph showing the shape of the fibers of the fibrous copper powder obtained in Example 1.

Applicant: Sumitomo Metal Mining Co., Ltd. Procedural amendment (0 or more)

Claims (2)

[Claims] (1) The major axis is 1 to 15 μm and the aspect ratio is 5 to 25.
fibrous copper powder. (2) A solution containing steel ions is reacted with ammonium ions in an amount equivalent to or more than the copper ions in the solution to form steel ammonium complex ions, and then the temperature of the solution is raised to 80°C.
The copper hydroxide is heated to 150 to 450°C in a reducing atmosphere to form a fibrous steel that is reduced to copper by reacting an equivalent amount or more of caustic alkali with copper ions while maintaining the following conditions: Method for producing copper powder.