Purified concentrated aqueous leucoindigo salt solutions
US11384245B2 · kind B2 · utility
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24Claims
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Key dates
| Filing date | Aug 10, 2018 |
| Grant date | Jul 12, 2022 |
| Priority date | — |
| Expiry date | Jul 5, 2039 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01D3/14
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
Aqueous leucoindigo solution comprising an aromatic amine, in particular aniline or aniline and N-methylaniline, wherein the concentration of the aromatic amine is below 200 ppm, wherein the leucoindigo salt in the solution is in the form of a mixed sodium and potassium salt, wherein the molar ratio of sodium to potassium is in the range of from above 3:1 to 10:1, preferably wherein the concentration of the salt is in the range of from above 25 to 45% by weight, based on the total weight of the solution.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.