TH78041B - Methods of hair dyeing and redyeing - Google Patents

Abstract

------13/02/2019------(OCR) Page 1 of 1 Summary of the invention A method of hair dyeing and re-dying comprising the hair dyeing step of forming an oxidized dye polymer comprising a specific oxidizing dye and having a distinct property on the inside of the hair, and a re-dying step of performing a treatment including at least the degradation of the oxidized dye polymer by allowing the re-dyeing hair dye composition containing an oxidizing agent and having a pH higher than 9.6 at the time of application to act on the hair following the hair dyeing step. By the above method, while sufficient hair dyeing power is achieved at the time of the initial hair dyeing, the degradation treatment of the dark-colored oxidized dye polymer formed on the inside of the hair by the oxidizing dye is performed without any decolorizing treatment, and the hair dyeing treatment or bleaching treatment so that the lightening effect can be achieved satisfactorily. ------------ A method of hair dyeing and re-dying comprising the hair dyeing step of forming a oxidizing dye polymer comprising a specific oxidizing dye and having a distinct property on the inside of the hair, and the re-dying step of performing a treatment including at least the degradation of the oxidized dye polymer by allowing the re-dyeing hair dye composition containing an oxidizing agent and having a pH higher than 9.6 at the time of application to act on the hair following the hair dyeing step. By the above method, while sufficient hair dyeing power is achieved at the time of the initial hair dyeing, the degradation treatment of the dark-colored oxidized dye polymer formed on the inside of the hair by the oxidizing dye is performed without any decolorizing treatment by a decolorizing agent, and the hair dyeing treatment or bleaching treatment so that the lightening effect can be achieved satisfactorily. Oxidized dye polymers containing specific oxidation dyes and having distinct properties in the hair, and repeated hair dyeing procedures of the treatment including at least the degradation of the oxidized dye polymers by allowing the repeated hair dye mixture containing the oxidizing agent and having a pH higher than 9.6 at the time of application to act on the hair after the hair dyeing procedure by the above method, while sufficient hair dyeing power is achieved at the time of the initial hair dyeing, the degradation treatment of the dark-colored oxidized dye polymers generated within the hair by the oxidation dye is performed without any decolorization treatment, and the dyeing treatment or bleaching treatment for the hair to achieve a light color can be performed satisfactorily.