| 摘要 |
PURPOSE:To obtain an indicator suitable for visual confirmation of the service life of a product having a limited service life, for example, an insecticide, an aromatic, a deodorizer or a medicine in particular, by incorporating a solution of coloring matter in an organic solvent into a base material and utilizing the change in color tone due to vaporization of the organic solvent. CONSTITUTION:This time indicator is formed by incorporating a solution of coloring matter in an organic solvent into a base material through coating, impregnation or dropping, and utilizes a mechanism in which a change in color tone is caused by vaporization of the organic solvent. The organic solvent is selected from among those capable of causing the original color of coloring matter to substantially disappear when said solution is incorporated into the base material, and preferred examples thereof are those having a boiling point of about 150-400 deg.C, including an alcohol, an ester, an ether, a ketone, and a nitrogenous compound. The amount of the organic solvent used in this indicator may be suitably selected depending upon the service life of a product to which the indicator is applied. The base material may be the same as those conventionally used for, e.g., a mothproof sheet. |
