Hair dye - contains oxidn dyes with a thiourea deriv - reducer and complexer for better stability

摘要

Human hair is dyed with oxidn dyes and additives by treatment at 10-40 degrees C with solns, emulsions or creams contg 0.05-2 wt.% of a thiourea deriv of formula: (where R is H or 1-4C alkyl) with 0.1-3% of a reducer (thioglycolic acid in water soluble salt form) and 0.1-2% of an org. complexer (EDTA insol salt form). An example of (I) is thiourea dioxide. Use of (I) with the reducer allows fuller and more uniform colour development and prevents precolouration of the mixt.