Nissan Chemical Industries Limited

Noriyuki Takakuma

Kiyomi Ema

Tohru Nishimura

Naoki Kawashita

Kouji Yamaguchi

Isao Ota

Kenji Tanimoto

Yoshiyuki Kashima

Daisuke Shimizu

Gen Yamada

A coating-forming composition for an electrical steel sheet that maintains excellent insulating properties, corrosion resistance, adhesion, and the like required in a coating for an electrical steel sheet, and exhibits excellent viscosity stability, with an increase in viscosity over time being kept gradual. A coating-forming composition for an electrical steel sheet comprises colloidal silica, a phosphate, phenylphosphonic acid or a salt thereof, and an aqueous medium.

Silica sol containing phenylphosphonic acid and applications thereof

A method for producing an active silicic acid solution in which the existing amount of foreign matters as plate-like fine particles is reduced and a method for producing a silica sol in which such foreign matters are reduced. The method fulfills the following condition; the existing amount of plate-like fine particles having a length of one side of 0.2 to 4.0 &#x3bc;m and a thickness of 1 to 100 nm is measured to be 0% to 30% in accordance with measuring method A, the method including the steps of: preparing an active silicic acid solution by subjecting an alkali silicate aqueous solution having a silica concentration of 0.5% by mass to 10.0% by mass to cation-exchange to remove alkaline components; and filtering the active silicic acid solution through a filter whose removal rate of particles having a primary particle size of 1.0 &#x3bc;m is 50% or more.

Method for producing purified active silicic acid solution and silica sol

A method for producing an active silicic acid solution in which the existing amount of foreign matters as plate-like fine particles is reduced and a method for producing a silica sol in which such foreign matters are reduced. The method fulfills the following condition: the existing amount of plate-like fine particles having a length of one side of 0.2 to 4.0 &#x3bc;m and a thickness of 1 to 100 nm is measured to be 0% to 30% in accordance with measuring method A, the method including the steps of: preparing an active silicic acid solution by subjecting an alkali silicate aqueous solution having a silica concentration of 0.5% by mass to 10.0% by mass to cation-exchange to remove alkaline components; and filtering the active silicic acid solution through a filter whose removal rate of particles having a primary particle size of 1.0 &#x3bc;m is 50% or more.

To provide a method for producing an alkali silicate aqueous solution containing a reduced amount of foreign substance of plate-like fine particles and a method for producing a silica sol containing a reduced amount of foreign substance of plate-like fine particles. A method for producing an alkali silicate aqueous solution fulfilling the following condition: the existing amount of plate-like fine particles having a length of one side of 0.2 to 4.0 &#x3bc;m and a thickness of 1 to 100 nm is determined to be 0 to 30%. The method for producing an alkali silicate aqueous solution includes the steps of adjusting a silica concentration of an alkali silicate aqueous solution to 0.5 to 10.0% by mass and filtering the alkali silicate aqueous solution through a filter having a removal rate of particles with a primary particle size of 1.0 &#x3bc;m of 50% or more.

Method for producing purified alkali silicate aqueous solution and silica sol

[Problems to Be Solved] To provide a method for obtaining a polishing composition by which a polishing speed is high and the polished surface has little surface failure. [Means to Solve the Problems] The present invention relates to a production method of a polishing composition containing zirconia oxide sol including: baking at a temperature ranging from 400 to 1000&#xb0; C., a zirconium compound having d50 (where d50 represents a particle diameter meaning that the number of particles having this particle diameter or less is 50% of the total number of particles) of zirconium compound particles of 5 to 25 &#x3bc;m and d99 (where d99 represents a particle diameter meaning that the number of particles having this particle diameter or less is 99% of the total number of particles) of zirconium compound particles of 60 &#x3bc;m or less, wherein d50 and d99 are measured by measuring a slurry of the zirconium compound by a laser diffractometry; and wet-grinding a powder of zirconium oxide obtained in the above baking in an aqueous medium until d50 of zirconium oxide particles becomes 80 to 150 nm and d99 of zirconium oxide particles becomes 150 to 500 nm, wherein d50 and d99 are measured by measuring the slurry of the zirconium compound by a laser diffractometry. [Selected Drawings]None.

Production method of polishing composition

A method of milling cerium compound by means of a ball mill using a milling medium, characterized in that ratio H/r of radius r of a cylindrical ball mill container and depth Hof the milling medium in the ball mill container disposed horizontally ranges from 1.2 to 1.9, and the ball mill container is rotated at a rotational speed which is 50% or less of critical rotational speed N=299/rof the ball mill container converted from the radius r expressed in centimeter. The milling method can be carried out in a wet or dry process, and the cerium compound is preferably cerium oxide. The method can be also applied for producing a cerium compound slurry.

Method of milling cerium compound by means of ball mill

The production method for cerium oxide particles of the present invention is a method of producing a cerium oxide particle by heating a cerium compound from a normal temperature to a temperature range of 400&#xb0; C. to 1200&#xb0; C., and comprises at least a temperature raising stage of a temperature rise speed of 2&#xb0; C./hour to 60&#xb0; C./hour, or proceeds via a stage of heating while supplying a humidified gas in a temperature raising process. By the method of the present invention, a cerium oxide powder whose particle diameter distribution of primary particles is narrow can be obtained. An aqueous cerium oxide slurry produced from the powder enables an improvement in the productivity and a reduction in the cost of a polishing step, because if it is used as an abrasive a high-quality polished face is obtained without deteriorating the polishing speed. The aqueous cerium oxide slurry of the present invention is particularly useful as an abrasive for final finish of a substrate whose main component is silica.

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Sodegaura, Japan

Noriyuki Takakuma