Prise winners list

The world's first nanoparticles dispersing device that makes practical use of nonoparticles

Kure-City, Hiroshima Prefecture
Kotobuki Industries Co., Ltd.
Other award winners
Yoshifumi Dainen, Toshiya Kitakaze, Takashi Tahara
Recommended by
Kikuo Okuyama

Inkyo, Mitsugi  (61)
Chemical Engineering Dept.
Chief Engineer

We produced a machine that was beyond customer's needs. It was five years later that the machine created a new market

Fine particles, the diameter of which is 1nm (1/1-billion m = 1/1-million mm), are called nanoparticles. If metallic oxides and organic pigments are pulverized to nanoparticles, they have many prominent properties. However, namoparticles have a property that they intertangle with each other and agglomerate and so it was necessary to disperse them in order to use them as industrial materials. Kotobuki Industries Co., Ltd. found that a beads mill (crusher), which mixed a material blended with a liquid with tiny small ceramic beads and stirred/pulverized it, could be also used to produce a particles dispersing device. By using ultra-small beads of 0.1mm diameter and controlling the stirring energy precisely, the company succeeded in dispersing nanoparticles evenly and materialized practical use of them. Currently a dispersing device that uses beads of 0.015mm is also manufactured.


The company developed a new product by daringly using tiny beads. Everybody thought, "Can such beads be really used?"

Mr. Inkyo, a true engineer, has worked for development of chemical industrial machines such as a centrifugal separator, filter and crusher. 
"Our company modified a Swiss-made crusher (mill) and developed our own crusher "Apex Mill" in 1986. That crusher is the origin of our present nanoparticles dispersing device."
Apex Mill was a beads agitating attrition mill (agitation mill) commonly known as a beads mill that pulverized a material into small particles. Firstly, powdered material was solved into water to make a liquid (slurry). Subsequently ceramic beads, which were hard and highly abrasion-resistant, were mixed with the liquid and it was stirred to pulverize the material into small particles. The smaller the beads were, a material was pulverized into the smaller particles. Very tiny beads of 0.3mm diameter appeared in 1992, and the company aimed to develop a mill that could use those tiny beads. At that time, everybody thought that the 0.3mm diameter beads were sufficiently good. However, there was a challenger in any field. Three years later in 1995, a beads manufacturer developed beads of 0.1mm diameter. Needless to say, there was no crusher that could use such tiny beads. This situation stimulated Mr. Inkyo, a pure engineer. He started to develop a crusher that could use beads of 0.1mm diameter.
"However, the beads were too small, and so the filter was clogged when the finished particles were separated from the beads. While at a loss what to do, he thought of an idea of revolving the slurry at high speed and separating the beads and finished particles by centrifugal force. Our technology for our centrifugal thickener for wastewater treatment helped us to develop a new crusher."
However, a new innovative crusher "Ultra Apex Mill" was not readily accepted in the market. People said, "What on earth can the 0.1mm beads be used for?"
"In such a situation, a manufacturer asked us if we could turn the barium titanate, which was the material for a laminated ceramic capacitor, into submicron particles (1/10000mm). The manufacturer asked us to, instead of pulverizing them, disperse the agglomerated particles without destroying their crystals. We could meet the customer's request very successfully. Then we thought that the new model could be used also for dispersion of smaller nanoparticles."

Finally they found a new usage for the Ultra Apex Mill, dispersion of nanoparticles. They were ahead of the times

Finding the new usage of the mill in dispersion of nanoparticles, Mr. Inkyo continuously conducted experiments. There were several methods for production of nanoparticles, and the thermal plasma method was one of them. In this method, a material was evaporated at high temperature and then cooled to produce nanoparticles. However, their surfaces were very active and so they agglomerated and became a lump. They could not be used as an industrial material unless they were dispersed. He intended to do it with a beads mill. He mixed beads of 0.1mm diameter with slurry of nanoparticles and put them into an Ultra Apex Mill. The slurry was stirred with a rotor that had many rows of radial pins and he thought that the agglomerated nanoparticles would be dispersed… Finally beads were separated with a centrifugal separator. 
"We found that when the 0.1mm beads were used, the nanoparticles could be dispersed evenly without destroying the crystals of agglomerated nanoparticles and they did not re-agglomerate."

In their experiments, they found that beads of 0.2mm diameter or larger could not disperse the nanoparticles because their impact was too strong. The beads of 0.1mm diameter, which people said was useless, solved the problem. By conducting experiments repeatedly, they found the know-how about how to disperse the nanoparticles in the optimal size according to materials and application. Nonetheless, they could sell only ten sets of the device in three years. However, the situation changed drastically in 2000. The government of US President Clinton decided to use the nanotechnology in its national strategy and so the "nonoparticles dispersing device" began to get attention. Domestic and foreign customers continuously visited the company.
"All the customers were surprised to see our device and said, 'Why haven't we used this device much more efficient than the conventional ones?' Then people began to use the nanoparticles for various purposes. Currently they are used for LCD color TVs, organic pigments of inkjet printer, dielectric material of laminated capacitor, photocatalyst, metallic paste, conductive paints and cosmetics. 
At first, people thought that the nanoparticle dispersing device was a product made by an egocentric engineer. However, having confidence in their product, Mr. Inkyo and his development team conducted experiments persistently and finally in time this device developed a new market successfully.

Kotobuki Industries Co., Ltd.

Mar. 1935
48 million yen
500 (as of Dec. 2009)
Brief information:
The company manufactures cast products, steel materials and chemical industrial machinery. The Chemical Engineering Dept. produced its nanoparticles dispersing device by integrating the crushing, filtering and centrifugal separation technologies.

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Experiments are repeated to find the optimal dispersion method.


Nanoparticles dispersing device. Slurry is dispersed into nanopariticles within the center cyoinder.


Up: slurry of barium titanate before dispersion (right) and the same after dispersion (left), the cloudy slurry became almost transparent; Low: ink pigments, which settled as large particles, (right) became a black colloid by dispersion of nanoparticles.