| 摘要 |
<p>A method of applying dye to keratin fibres comprises pretreating the fibres by contacting them with an alkaline solution of an amphoteric surfactant, and thereafter aplying dye to the pretreated fibres from a dyeing solution substantially deficient of surfactant-type levelling agents. Also disclosed is a novel surfactant compound comprising an alkoxylated hydroxysulphobetaine of formula (I) where: R1 is a hydrocarbon group selected from the range C12H25 up to C21H43; and R2 and R3 are poly(alkylene oxide) groups, each having n alkylene oxide units, where 3 « n « 21. In another aspect, there is disclosed a method of applying dye to keratin fibres comprising contacting the fibres with a bath liquor comprising an alkaline solution of the above surfactant, and thereafter adding dye to the bath liquor and applying the dye to the fibres from the bath liquor.</p> |
