Patent ID: 7217803

Claim:
An azo dye of formula wherein R 1 is —CN, —COOR 5 , —CONR 6 R 7 or a heterocyclic ring, R 2 is unsubstituted or substituted alkyl, unsubstituted or substituted aryl, —CF 3 , —COOR 5 , —CONR 6 R 7 or —COR 5 , R 3 is hydrogen, —SO 3 M, alkyl, alkoxy, alkylcarbonyl, —NO 2 or halogen, R 4 is substituted aryl, substituted heteroaryl or an aryl-N═N-aryl radical, wherein one or both of the aryl radicals in aryl-N═N-aryl is/are unsubstituted or substituted, or a radical heteroaryl-N═N-heteroaryl, wherein one or both of the heteroaryl radicals in heteroaryl-N═N-heteroaryl is/are unsubstituted or substituted, R 5 is hydrogen, alkyl or unsubstituted or substituted aryl, R 6 is hydrogen, alkyl or unsubstituted or substituted aryl, R 7 is hydrogen, alkyl or unsubstituted or substituted aryl, M + is a phosphonium salt or N(R 8 ) 4 + , wherein the substituents R 8 are each independently of the other hydrogen, C 1 –C 16 alkyl or C 1 –C 4 alcohol n is a number 1, 2 or 3 and m is a number 1, 2 or 3, and when n is a number 2 or 3, each M + can be the same or different.