Abstract:
PROBLEM TO BE SOLVED: To provide titanium dioxide powder having high sintering activity.SOLUTION: This invention relates to crystalline titanium dioxide powder in the form of aggregated primary particles having a BET surface area of 30-65 m/g and a rutile content of 50-70%. It is produced by introducing titanium tetrachloride vapor and, separately therefrom, hydrogen, air or oxygen-enriched air into a mixing chamber, subsequently igniting the mixture of titanium tetrachloride vapor, hydrogen and primary air in a burner and burning the flame into a reaction chamber and subsequently separating off the solid from gaseous substances, where the amounts used therefor are selected so as to satisfy following equation: A=A=10{[(TiCl×H)/(amount of air×total gas)]/BET}, [in the equation, A=6-12 is obeyed]. The titanium dioxide powder can be used in the ceramics industry.
Abstract:
PROBLEM TO BE SOLVED: To provide a method for producing a titanium dioxide powder.SOLUTION: The crystalline titanium dioxide powder in the form of aggregated primary particles has a BET surface area of 70-100 m/g and a rutile content of higher than 10% but less than or equal to 40%. The method for producing the titanium dioxide powder includes: introducing titanium tetrachloride vapor, and separately therefrom, hydrogen, air or oxygen-enriched air into a mixing chamber; igniting a mixture of the titanium tetrachloride vapor, hydrogen and primary air in a burner to obtain a flame; burning the flame in a reaction chamber; and subsequently separating the solid from gaseous substances, wherein the amounts used are selected to satisfy expression A: A=10{[(TiClX H)/(amount of air x total gas)]/BET} (wherein A is 0.1-0.4).
Abstract:
PROBLEM TO BE SOLVED: To provide a titanium dioxide produced by thermal decomposition which exhibits satisfactory transparency and does not cause an unpleasant and dull feeling on a skin when used as a tanning preventive agent, and to provide a formulation for a tanning preventive agent using the same. SOLUTION: The titanium dioxide is surface-modified and covered with the silicon dioxide, is produced by the thermal decomposition, and especially, is produced by flame hydrolysis. The titanium dioxide and the formulation for a tanning preventive agent using the same is obtained by spraying a surface-treating agent onto the titanium dioxide covered with silicon dioxide, followed by treating the resultant product at a certain temperature. COPYRIGHT: (C)2006,JPO&NCIPI
Abstract:
PROBLEM TO BE SOLVED: To provide a silicon dioxide powder displaying a good thickening action combined with a short incorporation time into polymers, particularly polyester resins. SOLUTION: The silicon dioxide powder is pyrogenically produced in the form of aggregates of primary particles having a BET surface area of 200±25 m 2 /g, wherein the aggregates display an average surface area of 7,000 to 12,000 nm 2 , an average equivalent circle diameter (ECD) of 80 to 100 nm and an average circumference of 850 to 1,050 nm. COPYRIGHT: (C)2006,JPO&NCIPI
Abstract:
PROBLEM TO BE SOLVED: To provide a silicon dioxide powder displaying a good thickening action combined with a short incorporation time into polymers and good dispersibility in the polymers, particularly silicone polymers. SOLUTION: The silicon dioxide powder is pyrogenically produced in the form of aggregates of primary particles having a BET surface area of 150±15 m 2 /g, wherein the aggregates display an average surface area of 12,000 to 20,000 nm 2 , an average equivalent circle diameter (ECD) of 90 to 120 nm and an average circumference of 1,150 to 1,700 nm, and the powder is produced by a pyrogenic process. COPYRIGHT: (C)2006,JPO&NCIPI
Abstract:
PROBLEM TO BE SOLVED: To provide a silicon dioxide powder that can be incorporated quickly into liquid media. SOLUTION: The silicon dioxide powder is pyrogenically produced in the form of aggregates of primary particles having a BET surface area of 300±25 m 2 /g, wherein the aggregates display an average surface area of 4,800 to 6,000 nm 2 , an average equivalent circle diameter (ECD) of 60 to 80 nm and an average circumference of 580 to 750 nm, is produced. COPYRIGHT: (C)2006,JPO&NCIPI
Abstract:
PROBLEM TO BE SOLVED: To provide a silicon dioxide powder that can be mixed quickly into liquid media. SOLUTION: The silicon dioxide powder is a pyrogenically produced silicon dioxide powder in the form of aggregates of primary particles having a BET surface area of 90±15 m 2 /g, wherein the aggregates display an average surface area of 10,000 to 20,000 nm 2 , an average equivalent circle diameter of 90 to 130 nm and an average circumference of 1,000 to 1,400 nm. The powder is produced by a pyrogenic process in which SiCl 4 and a second silicon component selected from the group comprising H 3 SiCl, H 2 SiCl 2 , HSiCl 3 , CH 3 SiCl 3 , (CH 3 ) 2 SiCl 2 , (CH 3 ) 3 SiCl and (n-C 3 H 7 )SiCl 3 are mixed with primary air and a combustion gas and burnt into a reaction chamber. At this time, secondary air is also introduced into the reaction chamber, and the feed materials are chosen so that the adiabatic flame temperature T ad becomes 1,810 to 1,890°C. A dispersion containing the pyrogenically produced silicon dioxide powder is also provided. COPYRIGHT: (C)2006,JPO&NCIPI
Abstract:
PROBLEM TO BE SOLVED: To provide a silicon-titanium mixed dioxide which is produced by pyrolysis and does not exhibit drawbacks of prior art. SOLUTION: There is provided a surface-modified silicon-titanium mixed dioxide produced by pyrolysis. The method of producing the mixed dioxide comprises: spraying water on the silicon-titanium mixed dioxide produced by pyrolysis in a mixer as needed; spraying a surface-modifying agent; mixing as needed; and then temperature-treating the obtained mixture. COPYRIGHT: (C)2006,JPO&NCIPI
Abstract:
PROBLEM TO BE SOLVED: To produce aqueous dispersion liquid containing a cerium oxide easily and to regulate grain size reproducibly such that the dispersion liquid contains impurities at a small ratio. SOLUTION: From a core of doped silicon dioxide having a low-level structure produced by thermal decomposition, the aqueous dispersion liquid containing a cerium salt solution or the mixture of the salt solution and a suspension, more preferably powder produced when a cerium oxide shell is formed by spraying them, is produced such that the powder in the dispersion liquid has an average secondary grain size not exceeding 0.2 μm. COPYRIGHT: (C)2004,JPO
Abstract:
Process for preparing an aqueous dispersion which has a pH of 9 to 14 and comprises particles of a pyrogenic titanium- silicon mixed oxide powder having a proportion of silicon dioxide of 75 to 99.99% by weight and of titanium dioxide of 0.01 to 25% by weight, whose mean aggregate diameter in the dispersion is not more than 200 nm, and at least one basic, quaternary ammonium compound.