| 摘要 |
PURPOSE:To use a temperature indicating sheet for managing the preservation of a frozen food, by making a color identifying agent melt above a specified temperature and permeate a diaphragm varied in the thickness so that the color forming rate thereof is varied with the time of permeation to form color in the sheet above a specified temperature. CONSTITUTION:A wax-like substance (e.g. methyl myristate) meltable above a specified temperature and a color identifying agent 2 (e.g. dye) are contained into each of microcapsules 4. These capsules 4 are applied on a sheet together with a binder 5. Then, diaphragms 1 and 1' are applied on the binder 5 with varied thicknesses in ethylene-vinylacetate resin or the like. Then, a display layer 3 adapted to absorb the color identifying agent 2 is applied on the diaphragms to form a temperature indicating sheet. Then, the capsules 4 are broken and stuck on a frozen food. When the frozen food rises above a specified temperature, the color indientifying agent 2 melts, exudes to the binder 5 to form color in the display layer 3, first passing through the thin diaphragm 1' and again, through a thick diaphragm 1 delayed. Thus, this temperature indicating sheet makes it possible to judge on how long the food is exposed to the temperature above a specified value. |
