| 摘要 |
PROBLEM TO BE SOLVED: To maintain an initial clean state on an external appearance of a sheet even if the sheet is discolored by ultraviolet ray by providing a thermosensitive color developing layer on an upper surface of a sheet body, and covering a overall upper surface of the layer with a coloring layer via a protective layer. SOLUTION: A color developing layer 2 is provided on a front surface of a sheet body 1, a protective layer 3 is provided on the overall upper surface, and a colored layer 4 is provided on the overall upper surface of the layer 3. As a result, the layer 2 is covered with the layer 4. The body 1 is preferably formed of nonwoven fabric. Since the body 1 of the fabric has waterproofness, it is convenient in the case of scattering water to a plant. The body 1 also has tough durability and a satisfactory sense of beauty. The layer 2 can be formed by using well known thermosensitive color developing material in which lactone, lactam or colorless or monochromatic leuco dye having a spiropyran ring and acidic substance partly retained in binding agent. The layer 3 can be formed by using well known material made of water soluble resin. |
