POROUS ALUMINA FREE-STANDING FILM, ALUMINA SOL AND METHODS FOR PRODUCING SAME

• Main Authors: NAGAI, NAOFUMI, MIZUKAMI, FUJIO
• Format: Patent
• Language: English; French; German
• Published: 31.08.2011
• Subjects: CHEMISTRY; COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM,CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THERARE-EARTH METALS; INORGANIC CHEMISTRY; METALLURGY

The present invention provides a porous alumina self-supporting film which has a sufficient strength to be used as a self-supporting film, is flexible and has a high transparency; an alumina sol that is composed of fibrous or needle-like boehmite particles dispersed in a solution and that has a high storage stability; and methods for producing such a film and such an alumina sol. More specifically, the invention provides a porous alumina self-supporting film which is composed of a collection of fibrous or needle-like alumina hydrate particles or alumina particles having an average breadth of 1 to 10 nm, an average aspect ratio (length/breadth) of 30 to 5,000 and an average length of 100 to 10,000 nm, has an orientation, has a pore distribution with a pore diameter d peak of 0.5 to 20 nm, is flexible, has a high transparency, and has the ability to luminesce when excited by ultraviolet light; an alumina sol which has a Na, K and SO 4 content of 0 to 1 ppm, has an orientation when the particles are collected, and luminesces when excited by ultraviolet light after being fired at 250 to 900°C; and methods for producing such a film and such an alumina sol.