Method of reducing the tendency of particulate active oxygen compounds to cake
US4849198A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 7, 1988 |
| Grant date | Jul 18, 1989 |
| Priority date | — |
| Expiry date | Jun 7, 2008 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01B15/106
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Particulate, active-oxygen compounds, especially sodium percarbonate, tend to cake during storage, which makes it more difficult to handle them. The invention reduces this caking tendency while the active-oxygen content remains essentially unchanged. The method of achieving this comprises bringing the active-oxygen compound in contact with such an amount of an aqueous solution containing one or more phosphonic acid compounds capable of chelate complex formation that the weight ratio of active-oxygen compound to phosphonic acid compound is 100:0.1 to 100:10, preferably 100:1 to 100:3, and subsequent drying. Sodium percarbonate is used in particular as active-oxygen compound and 1-hydroxyethane-1,1-diphosphonic acid as a 3 to 30% by weight aqueous solution is used as phosphonic acid compound. Sodium percarbonate wet salt is preferably washed with this solution, freed of excess solution and dried. Percarbonate treated in this manner hardly tends to cake at all and exhibits a greater active-oxygen stability.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.