| 摘要 |
PURPOSE:To produce a copying material capable of erasing a copied characters etc., by adding a water, by a method wherein an aqueous solution mainly composed of a cobalt thiocyanate is applied on a substrate and dried to form the copying material. CONSTITUTION:A coating liquid is prepared by dissolving a composition composed mainly of a cobalt thiocyanate with an alkylene glycol, a polyalkylene glycol, etc., mixed therewith as a color deeping agent in a water, an organic solvent, or a mixed solvent of water and organic solvent. This coating liquid is infiltrated and held in a substrate such as a paper, cloth, moisture-absorbing rubber, and moisture-absorbing plastic sheet; in this manner, a copying material is produced. An addition amount of the cobalt thiocyanate to the solvent is generally 0.1-200 pts.wt., preferably 0.5-140 pts.wt., to 100 pts.wt. of the solvent. As the organic solvent, methanol, ethanol, ether, acetone, etc., are used. |
