NOVEL ACID-TYPE HAIR COLOR TECHNOLOGY Inside of hair� I z II z � Hair pro Carboxyl group of hair protein 45 Fi gu re 12. Proposed mechanism of the formation of dye complex with aluminum ion. The state of the aluminum ion in the hair was speculated by X-ray fluorescent spectrum. This model shows that one or two ligands of aluminum ion combine with hair protein and dye. COLOR BRIGHTNESS EFFECT AND COLOR LONGEVITY EFFECT The color brightness and the color longevity effects of the "permanent" acid hair color described in the result of the tress rest were superior to chose of the conventional oxidative hair color, especially in the fashion shade. And the panel test verified char the "permanent" acid-type hair color was comparable to the conventional oxidative hair color in terms of the color brightness effect and the color longevity effect. In Figure 7B, the "permanent" acid-type hair color seems to have more brightness than that of the con­ ventional hair color. Since a conventional oxidative hair color bleaches and dyes hair simultaneously, the color brightness effect may be reduced by the bleaching process (4). However, this "permanent" acid-type hair color can show rhe color brightness effect more effectively than char of a conventional oxidative hair color, because the "perma­ nent" acid-type hair color requires no bleaching process. The result of the sensory evaluation described above also suggests chat the "permanent" acid-type hair color was also preferable in terms of smoothness and shine. Acid-type hair color that was considered "semi-permanent hair color" was improved to perform at least at the same level as "permanent hair color" by the dye-metal ion complex technology. Furthermore, rhe "permanent" acid-type hair color (1) does not damage the hair as occurs after using the conventional oxidative hair color, (2) needs no patch rest for evaluating safety, and (3) causes no irritating smell such as that a\ways generated upon the use of a conventional hair color (9,13). These factors also give a considerable advantage to the "permanent" acid-type hair color.

46 JOURNAL OF COSMETIC SCIENCE CONCLUSIONS 1. The key technology of this study is the formation of a dye-metal ion complex technology that can allow "permanent" acid-type hair color to form on insoluble dye­ metal ion complex in hair but not in the bottle. 2. The performance of "permanent" acid-type hair color, which contains A1Cl 3 ·6H 2 O and glycolic acid, is quite satisfactory as "permanent" hair color. 3. It is proposed that the dye-metal ion complex consists of dye, metal ion, and hair protein. REFERENCES (1) T. Mitsui, Ed. "Hair Color, Hair Bleach," in New Cosmetic Science (Elsevier, Tokyo, 1997), pp. 431-438. (2) Y. Arai, K. Ohno, and U. Tamura, Effect of oils in oxidation hair dye on its dyeing ability. Shikizai., 72, 19-24 (1999). (3) J. Kawase and T. Yoshihar, The trend of development of future problems of semi-permanent hair coloration, Fragrance]., 3, 18-28 (1994). (4) F. Matsuzaki, T. Yanaki, K. Shibata, K. Ohno, H. Nakajima, T. Okuda, M. Yamaguchi, and Y. Kumano, Development of phase-inverting cream hair colorant, 21'' IFSCC International Congress, Berlin, CD-ROM, P3 l (2000). (5) F. E. Wall, "Bleaches, Hair Colorings, and Dye Removers," in Cosmetics Science and Technology, M.S. Balsam and E. Sagarin, Eds. (Wiley-lnterscience, New York, 1997), Vol. 2, pp. 296-343. (6) Y. Nishida, The development of new functional hair colorant, Fragrance]., 5, 29-35 (1998). (7) K.C. Brown, "Hair and Hair Care," in Cosmetic Science and Technology, D. H. Johnson, Eds. (Marcel Dekker, New York, 1997), Series 17, pp. 191-215. (8) M. Oku, H. Nishimura, and H. Kanehisa, The analysis of dissolved proteins from bleached hair,]. Soc. Cosmet. Chem. Japan., 21, 198-209 (1987). (9) Y. Iwamoto, The trend of development and function of temporary hair-coloration and semi-permanent hair-coloration, Fragrance]., 8, 33-39 (2001). (10) Y. Kubo and T. Iijima, Dye elution from aluminum lakes of synthetic food colors (VI), Shikizai., 60, 2-13 (1987). (11) Y. Kubo, M. Shirai, and T. Iijima, Dye elution from aluminum lakes of synthetic food colors (VII), Shikizai., 60, 83-93 (1987). (12) T. Mitsui, Ed. "Hair Color, Hair Bleach," in New Cosmetic Science (Elsevier, Tokyo, 1997), pp. 74-76. (13) M. Ando and T. Matsuo, Recent progress in hair coloring technology-Development of non-odor hair colorants, Fragrance]., 8, 33-39 (2001).