30128-01-9Relevant articles and documents
Lyophilized dyes and the use thereof to color keratinic fibers
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, (2008/06/13)
A dye for coloring hair is one of an indamine, indoaniline, indophenol, diaminobenzoquinone or mixtures thereof which is lyophilized from a solution of the dye in an organic solvent or in an aqueous solution of the organic solvent by freezing the solution at a temperature of -200° to -60°C, and then subliming the frozen solution under a vacuum at a temperature lower than the melting point of the frozen solution. The thus lyophilized dye can be desorped to eliminate, if necessary, residual moisture. The lyophilized dye can be solubilized in an aqueous solution to produce a hair dye composition and can be present therein in amounts of about 0.0005-4 percent by weight of said composition.