| 摘要 |
PURPOSE:To reduce an erasing stage and to improve the efficiency of a photoengraving operation by incorporating an aq. phosphoric acid modified starch powder soln. and solvent which dissolves or swells an image part into the titled agent. CONSTITUTION:This retouching agent contains the aq. phosphoric acid modified starch soln. and the solvent which dissolves or swells the image part. The substitution rate (degree of esterification) of the phosphoric acid modified starch is theoretically possible up to 3 degree of esterification at which all of the three hydroxyl groups of the glucose residues of the starch are esterified and the range of the preferable substitution rate is 0.03-1.0 and is more preferably 0.05-0.6. The content of the phosphoric acid modified starch in the retouching agent is more preferably 0.1-3wt%. The solvent which dissolves or swells the image part includes, for example, lactones, etc. |
