Method of making flowable alkaline thiosulfate/alkaline sulfite and the product thereof
US5270154A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 31, 1992 |
| Grant date | Dec 14, 1993 |
| Priority date | — |
| Expiry date | Jan 31, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C5/38
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method for making flowable alkaline thiosulfate, flowable alkaline sulfite, or a combination of the two, by blending an alkaline thiosulfate, an alkaline sulfite, or a combination of the two, with an alkali metal arylsulfonate.formaldehyde in an amount effective to render the alkaline thiosulfate, the alkaline sulfite, or the combination freely flowable, and the product of this method. It has been found that the product of this method, such as freely flowable ammonium thiosulfate powder mixture, can be stored in a freely flowable condition for extended periods of time and can be dissolved into solution readily to form a clear non-turbid solution. The freely flowable ammonium thiosulfate powdered mixture of the present invention is particularly useful as a photographic fixative and bleach fixative for processing photographic elements.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.