| 摘要 |
PROBLEM TO BE SOLVED: To provide a method to achieve a reversible change of the color of hair wherein the change of the color can be effected by a beautician or a consumer in a simple manner. SOLUTION: This invention relates to the method for effecting a change of color of hair, and comprises following steps, (a) dyeing the hair to a first color with an aqueous alkaline dyeing composition comprising at least one azo dye of the formula (I), (I): A-N=N-B [wherein A is a monovalent group which binds an azo group through a carbon atom, and which is free of carboxy group, sulfo group, or quaternary ammonium group, and B is a monovalent group containing a dissociative proton and, which is free of carboxy group, sulfo group, or quaternary ammonium group], wherein the azo dye is capable of reversible color change of hair in an aqueous medium, (b) rinsing the dyed hair with water and (c) subsequently treating the dyed hair with an aqueous acid formulation not containing substantially any dye to change wherein the color of the hair a second color. COPYRIGHT: (C)2005,JPO&NCIPI
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