| 摘要 |
PROBLEM TO BE SOLVED: To improve chemical resistance, light fastness and water resistance of a recording section by containing a water-soluble salt of a specified copolymer in a protective layer. SOLUTION: A water-soluble salt of a copolymer of a radical copolymerizable radical organic compound having benzotriazole groups and a radical polymerizable organic compound having carboxyl groups is contained in a protective layer. The benzotriazole groups absorbing strongly ultraviolet rays is introduced into molecules of a water-soluble salt to provide light fastness stabilized for a long period of time. Also, as the water-soluble salt is dispersed uniformly in a protective layer coating liquid, the effect of absorption of ultraviolet rays after coating is demonstrated uniformly. The usage ratio of the radical polymerizable organic compound having carboxyl groups is 50-500 pts.wt., preferably 100-300 pts.wt. to the radical polymerizable compound having benzotriazole groups of 100 pts.wt. The usage of water-soluble salt to the total solid amount of the protective layer is 5-80wt.%, preferably approximately 20-60wt.%. |
