| abstract |
PURPOSE: To obtain a composition for dyeing resistant to a shampoo or exposure of light, etc., giving clearly colored dye finishing and suitable for dyeing of natural fibers, especially human hair, comprising a mixture of an indole and an aldehyde in a reaction medium having a specific pH. n CONSTITUTION: This hair dye composition quickly initiating a color coupling reaction without using any acid catalyst and giving clearly colored dye finishing effect and resistant to oxidation of a generated color even under an alkaline condition because the hair becomes an effective accelerator of the reaction by previously forming an addition product (a coupler) of components A and B or forming the product on natural fibers (especially hair) is obtained by mixing (A) an indole expressed by formula I (R 1 to R 5 are each H, a 1-3C alkyl, an alkoxy, an aryl, etc.; R 6 and R 7 are each H, OH, NO 2 , a halogen, an aryl, etc.) with (B) an aldehyde, preferably a compound expressed by formula II (R 8 is H, CH 3 , an alkyl, an alkenyl, an alkynyl, benzyl, etc.) in a reaction medium of pH2-10. n COPYRIGHT: (C)1990,JPO |