Freeze indicators suitable for mass production
US7624698B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 6, 2008 |
| Grant date | Dec 1, 2009 |
| Priority date | — |
| Expiry date | Feb 6, 2028 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S252/962
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A freeze indicator employs, as active indicator element, dispersion of solid particles in a liquid medium which can be water or aqueous and which coagulates to provide an irreversible appearance change when subject to freezing. The liquid dispersion can be contained in an indicator volume around which extends a vapor block layer. The vapor block layer can prevent loss of liquid vapor from the dispersion and consequent drying out and dysfunctionality of the freeze indicator. For containing an aqueous medium, bilayer and trilayer laminate materials can be used which have a low water vapor transmission rate. The active indicator element can be a dilute colloidal dispersion of a metal such as gold or silver or other inorganic pigment material in water or an aqueous medium. Some embodiments avoid use of dispersants and the like and employ an active indicator element consisting of inorganic pigment particles, water and optionally an ice nucleating agent. Heavy water, or deuterated water can be components of the water, if desired.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.