| 摘要 |
PURPOSE:To quantitatively discriminate the lapse of the available period of a product by sandwiching fine porous particles which have adsorbed a component discolored by moisture between two sheets that transmit no water vapor, one or both of the sheets being transparent, and adhering the sheets by a synthetic resin application. CONSTITUTION:One of sheets 1 and 2 that transmit no water vapor is necessary to be transparent so that a color change may be confirmed and, for example, polyvinylidene chloride applied polyester or the like is used for the sheet. When checking from both surfaces is not required, an opaque laminate laminated by aluminum foils is used for the other of the sheets 1 and 2. An indicator ink 3 that has adsorbed a discoloring component discolored by moisture is made such that, after dissolved in distilled water and water is absorbed by a porous resin with a high water absorption, cobaltous chloride hexahydrate as the discoloring component is dried to fine particles and mixed with a non- aqueous resin binder. The indicator ink 3 is printed on the sheet 1 or 2. Then, by applying a synthetic resin application 4 around the ink 3 and adhering the sheets 1 and 2 to each other, the available period of a product is quantitative discriminated. |
