| 摘要 |
PURPOSE:To use a temperature indicting sheet for managing the preservation of frozen foods, by applying microcapsules containing a color identifying agent meltable at a specified temperature on a sheet together with a binder to form color when the sheet is exposed to the temperature above the specified value. CONSTITUTION:A wax-like substance (e.g. methyl myristate) meltable at a specified temperature and a color identifying agent (e.g. dye) 1 are contained in each of microcapasules 2. Then, a resin (e.g. ethylenevinylacetate copolymer and acrylic acid copolymer) different in the affinity from the color identifying agent 1 is used as binders 3 and 3' and the capsules 2 are applied on a sheet divided by the binders 3 and 3' to form a temperature indicating sheet. Then the capsules 2 of the sheet are broken and stuck a frozen food. As the frozen food rises above the specified temperature, the color identifying agent melts and exudes to the binders 3 and 3' to form color. Here, the layer of the color identifying agent and the binder 3 larger in the affinity forms color faster than the layer of the binder 3' smaller in the affinity. This temperature indicating sheet makes it possible to judge on how long the food is exposed to the temperature higher than the specified temperature. |
