Abstract
We have developed a new type of cationic surfactant C 12 A 4G (AG) for rinse out type hair conditioner. In this work, cosmetic novelty, characteristic properties of C 12 A 4G for use in hair conditioner were evaluated and the adsorption behavior of C 12 A 4G onto the hair, the mechanism of this characteristic properties were investigated from the viewpoint of surface chemistry.
C 12 A 4G is the name of an amide guanidine type cationic surfactant having a guanidino group as cationic group (G), an amide-methylene group for 4 methylene groups as spacer between an amide group and guanidino group to boost water holding capacity (A 4) and lauroyl group (C 12). It completely differs from the quaternary ammonium type cationic surfactants currently in wide use now.
The hair treated with C 12 A 4G or hair conditioner containing C 12 A 4G displayed excellent moisturizing effect even in low humidity. The major characteristics of C 12 A 4G were most apparent during rinsing when used in hair conditioner. This conditioner was able to increase smoothness of the hair to levels never before attained and made the user the feel that it was retained on the hair, leading to consumer confidence in the perceived damaging free effect of the conditioner. The characteristics of C 12 A 4G derive from its molecular structure and the aggregates with cetyl alcohol. We clarified the adsorption mechanism of C 12 A 4G onto the hair and analyzed the aggregates formed by C 12 A 4G and cetyl alcohol using DSC, ESR technics. The results suggested that C 12 A 4G highly adsorbed onto the hair and these aggregates possessed grater water holding capacity than conventional ammonium types. It is considered that these characteristic aggregates display unique conditioning functions when they work on the hair.
Moreover the safety test of C 12 A 4G was very good. In the near future C 12 A 4G certainly promises to displace quaternary ammonium types used in hair conditioners.
