Particle size control for acetylenic agents useful in condition monitoring systems
US7019171B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 2, 2004 |
| Grant date | Mar 28, 2006 |
| Priority date | — |
| Expiry date | Jan 21, 2025 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C273/189
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
Precipitation of polyacetylenic agents can be effected with control of a particle size parameter such as mean size or spread, by mixing a warm solution of the acetylenic agent with a cold precipitation fluid and appropriate selection of a constituent of the cold precipitation fluid and/or of the temperature conditions and collecting the precipitated acetylenic agent. Precipitation additives such as nitrocellulose or gelatin can usefully be employed. Solvents such as aqueous methanol and ethyl 3-ethoxypropionate can be useful. Polyacetylenic agents, e.g. substituted diacetylenics are useful to provide visual changes in condition-monitoring indicators such as time-temperature indicators, “TTIs”, useful as freshness indicators for radiation exposure monitoring and for other purposes. Controlled, small and/or consistent particle sizes of such polyacetylenic agents are helpful in providing consistent commercial properties, especially in inks in which they may be formulated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.