| 摘要 |
PURPOSE:To prevent the omission of data by the superposition of a detection mark and an image after image formation by providing the detection mark on at least one surface of a base material so as to be capable of erasing the same by heat and/or light. CONSTITUTION:A registering detection mark 3 erased by heat and/or light is provided on one surface of a base material 2 composed of a polyolefinic material. This detection mark 3 is formed from a compsn. wherein fine crystals of a liquid crystal are dispersed in a polymeric substance and the liquid crystal becomes transparent by heating, a compsn. wherein a liquid crystal is arranged in a polymeric substance at random and transparentized by changing the arrangement state of the liquid crystal by a magnetic field or a compsn. consisting of a polymeric substance and fatty acid and transparentized by the change of the crystal structure of fatty acid due to heat energy. As a substance due to light, a photochromic substance, for example, a spiropyrane or spirooxazine type compd. is used. |
