| 摘要 |
PURPOSE:To provide an additive for dampening water capable of being replaced with isopropyl alcohol, by containing a hydrophylic polymer substance containing a carboxyl group and a hydroxyl group obtained by saponifying a copolymer prepared by copolymerizing acrylic acid and vinyl acetate. CONSTITUTION:A hydrophylic polymer substance containing a carboxyl group and a hydroxyl group, which is obtained by saponifying a copolymer consisting of acrylic acid and vinyl acetate, is used. As the hydrophylic polymer substance wherein the carboxyl group (-COOH) and the hydroxyl group (-OH) are present in the same molecule, a copolymer of acrylic acid [CH2=CH(COOH)] and vinyl alcohol [CH=CH(OH)] is used. That is, -COOH is introduced from acrylic acid and OH is introduced from vinyl alcohol. The upper limit of the average polymerization degree of the polymer substance is determined by solubility to water and pref. about 5,000 and the lower limit thereof is pref. about 500 from the aspect of orientation property to the surface of a plate, that is, covering effect. The upper limit of a OH/COOH ratio is about 5(mol/mol) and the lower limit thereof is pref. 0.5(mol/mol). |
