| 摘要 |
PURPOSE:To enable the production of fine porous material having remarkably lower thermal conductivity than that of stationary air under normal pressure, by dispersing ultrafine powder in the presence of a surfactant and producing a porous material from the dispersed powder. CONSTITUTION:Ultrafine inorganic powder (hereinafter called as ultrafine powder) is added with a surfactant in a solvent and stirred to obtain dispersed higher order particles B having large size and composed of fine particles agglomerated with each other in a state shown in the figure. The dispersed solution is dried and the obtained ultrafine powder is formed as it is or after mixing with other inorganic fine powder and calcined. Since the formed article is free from large spaces between the higher-order particles B, B, the product is independent of the thermal conductivity of air. Accordingly, an ultrafine porous material having a thermal conductivity remarkably lower than that of stationary air of normal pressure can be produced by this process. The ultrafine powder particle is e.g. ultrafine silica powder produced by wet or dry process.
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