| 摘要 |
<p>1360939 Photographic silver dye-bleaching composition CIBA-GEIGY A G 16 Nov 1972 [29 Nov 1971] 52906/72 Heading G2C A dye bleach composition for the silver dyebleach process comprises an acid, a watersoluble iodide and at least one mercapto compound of the formula:- R 1 - SH where R 1 is an optionally substituted 2-6C aliphatic radical or optionally substituted phenyl which may be substituted by primary amino, 1-4C monoalkylamino, di (1-4C alkyl) amino, OH or COOH or a salt thereof the solubility of the compound being at least 5 x 10<SP>-4</SP> mole per litre of the composition and the compound having a vapour pressure at -20‹ to +100‹C which is at most equal to that of water at the same temperature. The compound may be 2-amino-3- mercapto-propionic acid, 2-dimethylamino-1- mercaptoethane, 2-diethylamino-1-mercaptoethane, 1, 2-dihydroxy-3-mercaptopropane, 1-amino-2-mercaptobenzene, mercaptoacetic acid, mercaptopropionic acid or mercaptosuccinic acid. The composition may contain a dye bleach catalyst. These compositions are stable and do not discolour.</p> |
