TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The coating liquid further contains a crosslinking agent selected from at least one of carbodiimide compound or oxazoline compound; and a solvent (preferably water) ( greater than or equal to 50 mass.%).    TECHNOLOGY FOCUS - POLYMERS - Preferred Sheet: The sheet (S1) further comprises a reflective layer which contains a white pigment and has light reflectivity, where the polymer layer is disposed between the reflective layer and the polymer base material. The sheet (S1) comprises at least two of the polymer layers, where one of the polymer layer further contains white pigment and is a reflective layer having light reflectivity, and another of the polymer layer is disposed between the reflective layer and the polymer base material. In the sheet (S1), the polymer layer comprises a structural portion derived from a crosslinking agent for crosslinking the composite polymer. In the polymer layer, a mass content of the structural portion derived from the crosslinking agent is 1-30 mass.% based on the content of the composite polymer. The polymer substrate is subjected to at least one surface treatment selected from a corona treatment, a flame treatment, a low pressure plasma treatment, an atmospheric pressure plasma treatment, and an ultraviolet treatment. The polymer layer has a thickness of 0.8-12 mu m. The polymer layer is provided in contact with a surface of the polymer base material. The polymer layer is an outermost layer which is disposed at the most distant position from the polymer base material. The polymer layer further contains a white pigment and is a reflective layer having light reflectivity. Preferred Components: The non-siloxane structural units comprise acrylic structural units. The polymer base material comprises a polyester resin having a carboxy group content of 2-35 equivalents/ton. Preferred Definitions:    R1 and R2=alkyl, aryl, aralkyl, alkoxy, aryloxy, mercapto group, amino or amide.    EXAMPLE - No suitable example given.