Temperature-indicating sheet
US4601588A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 16, 1985 |
| Grant date | Jul 22, 1986 |
| Priority date | — |
| Expiry date | Sep 16, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01K11/16
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The present invention provides a temperature-indicating sheet which, when exposed to temperatures higher than the prescribed temperature in temperature-control for the common low-temperature preserved goods, changes in color according to the exposure temperature and time. This object is attained by arranging one component which melts at the prescribed temperature and a substance which irreversibly changes in color in contact with said component through a membrane permeable to the component. The sheet of the present invention comprises a component which melts at the prescribed temperature, a substance which changes in color in contact with the component and a membrane permeable to the molten component, said component being included in microcapsules which can be broken by outer pressure at a temperature used, and in which the component and the substance are arranged at the opposite sides with respect to the membrane.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.