Solid particle dispersion filter dyes for photographic compositions
US4940654A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 30, 1989 |
| Grant date | Jul 10, 1990 |
| Priority date | — |
| Expiry date | Jun 30, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C1/83
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
Solid particle dispersions of dyes of the formula: EQU [D-(A).sub.y ]-X.sub.n where PA0 D that comprises an aromatic ring if y is O, A is an aromatic ring bonded directly or indirectly to D, PA0 X is a substituent, other than carboxy, having an ionizable proton, either on A or on an aromatic ring portion of D, having a pKa of about 4 to 11 in a 50/50 mixture (volume basis) of ethanol and water, PA0 y is 0 to 4, PA0 n is 1 to 7, and PA0 the compound has a log partition coefficient of from about 0 to 6 when the compound is in unionized form, are disclosed for filter dye layers of photographic elements. They may be coated in layers of photographic elements without a mordant, and they do not wander at coating pH's. At processing pH's, however, they are solubilized for easy removal and/or decolorization.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.