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US 4,701,525 AGranted
Polyazo dyestuffs having high UV absorption
AssigneeCiba-Geigy Corporation
InventorsThomas-Markus Rohr, Jakob Kuhn
Life of this patent
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Abstract
Compounds of the formula (B--L.sub.m --A--L'--B'.sub.n, (1) in which A is the radical of a bisazo or trisazo dye, L and L' are organic radicals and B and B' are cyclic organic radicals and at least one of the radicals B and B' has spectral absorption in the UV region and one of the radicals B and B' is different from 2,4-dihydroxyphenyl, m is 1 or 2 and n is 0, 1 or 2. The compounds are suitable for use as image dyes in photographic silver dye bleach materials.
Claims1
A compound of the formula
- (B--L--.sub.m A--L'--B').sub.n,
- in which A is a radical of the formula ##STR37## L and L' are --N.dbd.N--, B and B' are identical or different from each other and denote a radical of the formula ##STR38## and m is 1 or 2 and n is 0, 1 or 2.
Dependencies are inferred from the claim text.