| 摘要 |
<p>Novel hair colouring compositions are provided which give improved fade resistance. They comprise (i) one or more developers selected from amino aromatic systems capable of being oxidised and thereafter undergoing a single electrophilic attack, and (ii) one or more couplers selected from (A) phenols and naphthols having an active leaving group in the para position relative to the OH group, (B) 1,3-diketones containing the group (I) in which Z is an active leaving group, and (C) compounds containing the group (II) in which Z is an active leaving group, and X is an active leaving group or a non-leaving substituent, such that in the presence of an oxidising agent the or each developer reacts with the or each coupler substantially only at the position having the active leaving group Z and, if X is an active leaving group, X, which when applied to hair by the hair switch colouring method described herein and washed 20 times by the washing protocol described herein, gives a value of ΔE fade, measured as described herein, as follows: (a) when the composition is suitable for delivering a blonde or light brown shade ΔE fade is not more than 2.5, (b) when the composition is suitable for delivering a red shade, ΔE fade is not more than 5.0, (c) when the composition is suitable for delivering a black or dark brown shade ΔE fade is not more than 2.5.</p> |
