ALUMINA SOL FOR RECORDING MEDIUM

摘要

PURPOSE:To improve the selective adsorbability of a dye by preparing a sol forming a columnar boehmite aggregate whose particle shape has a specific aspect ratio in a state of being dripped on a collodion membrane made hydrophilic by diluting collodion to specific concn. of water and dried. CONSTITUTION:An alumina sol for a recording medium forming a bundle-like aggregate oriented in a fixed direction of boehmite whose sol particle has a columnar shape having an aspect ratio of 3 or less in a state of being dripped on a collodion membrane made hydrophilic by diluting collodion to 0.01 - 0.1% on a solid wt. basis by water and dried is prepared. This alumina sol is pref. dried at temp. equal to or less than the heat-resistant temp. of the collodion membrane and usually dried at room temp. and the shape of the alumina sol particle on the collodion membrane is observed using a transmission type electron microscope. Since the obtained alumina sol selectively adsorbs a dye with respect to the solvent in ink, printed matter having a sharp hue is obtained.