Ink formulations by mixing anionic waterfast dyes containing two or more carboxyl groups
US5062893A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 22, 1990 |
| Grant date | Nov 5, 1991 |
| Priority date | — |
| Expiry date | Jun 22, 2010 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09D11/328
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
Inks are provided comprising (a) at least two dyes corresponding to the formula ##STR1## wherein W is COOH, PA0 X is H, or COOH, PA0 Y is H, COOH, or SO.sub.3 H, PA0 Z is H, COOH, or SO.sub.3 H, and PA0 R is H, CH.sub.2 COOH, or CH.sub.2 CH.sub.2 COOH; with the proviso that there are at least two COOH groups and that the number of COOH groups is equal to or greater than the number of SO.sub.3 H groups, and (b) a solvent which may be water or a mixture of water and a water-soluble organic solvent provide excellent waterfast prints on paper. The inks preferably have a pH from about 7 to about 9.5. Also preferably, a phosphate is added to reduce kogation and a metal chelating agent is added to further reduce nozzle clogging.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.