The fastness, to repeated washing, of reactive dyes and pre-metallised acid dyes on nylon 6,6

Standard depth dyeings were prepared using three, unsulfonated 1:2 pre-metallised acid dyes as well as three reactive dyes on knitted nylon 6,6 fabric and the fastness of the dyeings to 20 repeated wash tests was determined. In the case of the three premetallised acid dyes, while aftertreatment with a commercial syntan/cation system as well as a modification of this commercial system reduced both the rate and extent of dye loss during repeated washing, the extent of dye loss which occurred was not unsubstantial. In contrast, the dyeings obtained using the three commercial reactive dyes suffered considerably lower dye loss during repeated washing.