J. Soc. Cosmet. Chem., 22, 379-398 (May 27, 1971) The Coloring of Human Hair with Semipermanent Dyes HAROLD H. TUCKER, Ph.D.* Presented September 22, 1970, Sixth IFSCC Congress, Barcelona, Spain Synopsis--A review is given of the recent literatnre on SEMIPERMANENT HAIR COLOR- ING. A series of tests is proposed for evaluating semipermanent colors. Eighty INDO- PHENOL and INDAMINE DYES have been prepared and these dyes have been evaluated for their substantivity to human hair, their fastness to light, and the stability to storage of the dye solutions. Structures have been assigned and physical properties determined for the ten dyes in this series that passed these three tests. INTRODUCTION In the USA, three types of dyes are commonly used for coloring live human hair. These are classed as permanent or oxidation colors, semipermanent colors, and temporary colors. In the permanent colors, intermediates of low molecular weight, such as p-aminophenol and p- phenylenediamine, are used in conjunction with hydrogen peroxide. Most of these intermediates are colorless and because of their small size they more readily penetrate the hair where they are slowly oxidized to their much larger colored forms. This type of hair color is characterized by its good fastness to shampooing. In the semipermanent colors, many different types of dyes are used, most of which have been developed for the textile industry. These are generally in their colored forms and, be- cause of their larger molecular size, do not penetrate the hair as veil as the permanent dyes. The semipermanent colors are characterized by a * 14 Chesterfield Road, Scarsdale, N.Y. 10583. 379

380 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS moderate resistance to shampooing and by the fact that hydrogen perox- ide is never used in their application. The main prerequisite ot5 a tem- porary color is that it be completely removed with one shampooing there- fore, penetration of the hair is not desirable. Dyes that are in their final colored form are used in temporary colors. They are generally applied to shampooed hair that has been towel-dried and is then set and dried with- out rinsing. In this paper only the semipermanent colors are considered. First, the types of dyestuff that have been suggested will be discussed, with references describing their methods of application. Then a testing method, for determining the suitability of dyes for semipermanent hair coloring, will be proposed. Next, the preparation, application, and test- ing of a series ot5 indophenol and indamine dyes will be described. Heald (1) has published an excellent review of the patents issued in this field prior to 1962. A study of this paper and of the current literature reveals that many classes of dyes have been proposed for use in semipermanent hair coloring. Since the patents in this field are much too numerous to mention, only a few of the more recent ones, for each class of dye and dyeing assistant, will be listed. DYESTUFFS USED IN SEMIPERMANENT HAIR COLORS Oxidation Dyes There are two classes of dyes, which are also used in the oxidation colors, that are applied as semipermanent colors without the addition of an oxidizing agent. The first of these comprises the nitro dyes which in- clude nitro-p-phenylenediamine (a red shade) and nitro-o-phenylenedi- amine (a bright yellow). Much work has been done on improving the solubility, increasing the substantivity, and/or modifying the color by replacing one or both of the hydrogens on the amino groups with ali- phatic or quaternary ammoninm radicals. Since 1934, 13 U.S. patents and 12 British patents have been issued on this modification. Four of the most recent of these patents are listed in the references (2-5). The second of these classes consists ot5 oxidation dye intermediates that are developed by atmospheric oxidation. These include polyamino- phenol compounds such as 2,4,6-triaminophenol and its derivatives (6). They are applied to hair from a 3% aqueous solution which has been adjusted to a pH of 8 just prior to application and are oxidized to their colored forms by a 15-min contact with air. In another method (7), the n itrogen-methylated or oxygen-methylated 1,2,4-trisubstituted benzenes,