PURPOSE: To improve light fastness by adding a copolymer of 2- hydroxy-4-(methacryloyloxyethoxy)benzophenone to a coated layer containing a color developer.

CONSTITUTION: A color developer such as salicylic acid and an adhesive such as starch are added to 2-hydroxy-4-(methacryloyloxyethoxy)benzophenone having a basic skeleton expressed by formula I to form a coated layer. In the formula R is hydrogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, a phenyl group, a nucleus-substituted phenyl group, an aralkyl group or a nucleus-substituted aralkyl group; n, m are an integer of 1 or higher. This copolymer displays an efficient function as an ultraviolet beam absorbent by adding about 2 to 70 pts.wt. of the copolymer for 100 pts.wt. of a color developer and thus indicates an improved light fastness. The copolymer is obtained by copolymerizing the polymers within a range of 10 to 80mol%.