Aftertreatment of Direct Dyes:-
by : ---
Aftertreatment of Direct Dyes:-
The wetfastness of many direct dyeings can be improved in various ways, i.e. (1) aftertreatment with cation-active organic fixing agents, (2) aftertreatment with formaldehyde, (3) aftertreatment with chromium salts, (4) diazotization of the dyes on the fibre and development with amines, phenols, or naphthols and (5) aftertreatment with diazonium compounds. The lightfastness of some direct dyeing can be improved by aftertreatment with copper salts. Copper salts are used alone, in combination with chrome, or in combination with new cation-active organic condensation products
