Patent ID: 7354965

Claim:
An azo compound represented by the following formula (I): wherein R 1 and R 2 respectively represent a hydrogen atom, an alkyl group having 1 to 21 carbon atoms, an alkenyl group having 2 to 21 carbon atoms, an aryl group having 6 to 21 carbon atoms or an aralkyl group having 7 to 21 carbon atoms and R 1 and R 2 may form a hetero ring with nitrogen atoms bonded therewith; R 3 represents a halogen atom, a trihalomethyl group, an alkoxy group having 1 to 21 carbon atoms or a nitro group; R 4 represents a halogen atom or a â€”SO 3 M group; M represents a metal atom cation or a cation comprising a nitrogen-containing compound; m denotes an integer from 0 to 5; and n denotes an integer from 0 to 4.