| 摘要 |
PURPOSE:To provide a high durability to repeated printing and suppress contamination of non-image parts, by providing a hydrophilic layer comprising a starch modified by phosphoric acid or a derivative thereof on the surface of an aluminum plate subjected to anodic oxidation. CONSTITUTION:A starch modified by phosphoric acid or a derivative thereof is obtained by bringing a starch into reaction with phosphorus oxychloride, a trimetaphosphate (of sodium, for example), an orthophosphate, a polyphosphate, phosphoric acid, an organic phosphonic acid or the like to form a phosphoric acid ester, and is a high molecular compound having the unit of the general formula, wherein each of R1-R3, which may be the same or different, is hydrogen or a residue of phosphoric acid or a derivative thereof. The modified starch is dissolved in an appropriate solvent, e.g., water or an alcohol such as methanol, in a concentration of 0.01-30wt% to prepare a coating liquid. The coating liquid is applied to the surface of an aluminum plate subjected to anodic oxidation, by any of dip coating, rotation coating, spray coating, curtain coating and the like. |
