PURPOSE: To prevent discoloring and fading with ultraviolet light by containing a condensed phosphate in a bath of a chlorine-based bleaching agent or post- treating a fabric dyed with an indigo dye in a solution of the above-mentioned phosphate after bleaching in subjecting the aforementioned fabric to bleaching treatment with the above-mentioned bleaching agent.
CONSTITUTION: A fabric (e.g. blue denim) dyed with an indigo dye is subjected to bleaching treatment in a bleaching bath of a solution containing a chlorine- based bleaching agent. In the process, a condensed phosphate (e.g. tripolyphopshate or pyrophosphate) is added to the aforementioned bleaching bath to bleach the fabric or the fabric is post-treated with an aqueous solution containing the above-mentioned condensed phosphate after the bleaching treatment to prevent the dyed fabric after the bleaching from discoloring or fading with ultraviolet light, etc. The condensed phosphate is used in an amount so as to provide a concentration within the range of preferably 0.3-3wt.% in the aqueous solution.
KAMIYAMA TAKASHI
NAKAMURA MASASHI
