Photoactivatable time-temperature indicator
US4737463A · kind A · utility
57Cited by
11References
23Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Oct 9, 1985 |
| Grant date | Apr 12, 1988 |
| Priority date | — |
| Expiry date | Oct 9, 2005 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S436/905
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A photoactivated time-temperature indicator is based on diacetylenic salts. A thermally unreactive ("inactive") diacetylenic salt (or a mixture of such salts) is mixed, in a polymeric matrix, with a material that generates acid upon exposure to light. Photoexcitation, preferably by UV or near UV light, causes the formation of a thermal reactive ("active") free diacetylenic acid. Following this activation step, a progressive color development occurs at a rate that increases with temperature. The indicator is useful for monitoring the freshness of perishable products, particularly those that require refrigeration.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.