Hair Cationic Dyes

Another very interesting and less explored field is the color changes observed when anthocyanins are in contact with colorless substances, which are not necessarily copigments, for instance, surfactants, emulsions, gels, proteins, DNA, cotton, wool, hair and so on (Bicard, 1999). For hair coloring, anthocyanins could be alternatives to existing synthetic systems and generate new direct dyes for hair (cationic dyes). 

Cationic dyes are occasionally used fur blueing or brightening the hair, frequently in combination with a fluorescent dyes. P. Krais discovered the brightening effect in 1929 by impregnation of rayon with a horsechestnut extract known as esculin, a fluorescent glycoside of 6,7-dihydroxycoumarin. Coumarin derivates are still used for wool and fur hair. 

Hall [61] as far back as 1937 first proposed intercellular diffusion. It has recently been clearly demonstrated by Feeder et al. [62] for metal complex dyes. Feeder has shown that a large cationic dye, rhodamine B (479Da) triphenyl pyrazine, a neutral molecule (311 Da) and the high-molecular-weight anionic oligomeric Synthappret BAP (>3,000Da) all penetrate hair through the intercellular route. 

Similar isoelectric points for hair and wool fiber are to be expected because chemical compositions of the cuticle are similar and because both fibers show similar dye-staining characteristics. Cuticle from both fibers stains more readily with cationic dyes than with anionic dyes [96], whereas the cortex stains readily to anionic dyes [121]. 

Uses Compatibilizer or antiprecipitant in dye bath of acid and cationic dyes mild dye Ieveier and/or stripping agent for acid dyes hydrophilic emulsifier skin and hair care prods. 

C.-E. Lin, Y.-T. Chen and T.-Z. Wang, Separation of benzenediamines, benzenediols and aminophenols in oxidative hair dyes by micellar electrokinetic chromatography using cationic surfactants. J. Chromatogr.A, 837 (1999) 241-252. 

Cationic polymers -of coal-tarfractions [HYDROCARBON RESINS] (Vol 13) -initiation of [INITIATORS - CATIONIC INITIATORS] (Vol 14) -of a-olefms [OLEFIN POLYMERS - POLYMERS OF HIGITEROLEFINS] (Vol 17) -in hair rinses [HAIR PREPARATIONS] (Vol 12) -in paper-making [PAPERMAKING ADDITIVES] (Vol 18) -m waste treatment of dyes [DYES, ENVIRONMENTAL CITEMISTRY] (Vol 8)... 

Exhaustive alkylation of aminonaphthols, such as 2-amino-7-naphthol, and coupling with diazotized aromatic amines generates yellow, orange, red, and brown cationic azo dyes. Compound 5 dyes human hair and polyacrylonitrile in brown shades [26],... 

Dyes such as methyl violet 8004-87-3 and methylene blue 6I-73-4 are used in rinses cationic azine and azo dyes are also used in tints. Their molecular size and charge prevent them from penetrating the hair, so that the color pattern in cross section is annular [24], The charge on the dyes, however, leads to a relatively stable ionic bonding of the dye to acid groups of the hair, which lasts through several washings. 

Color rinses represent the simplest way of altering hair color. The hair is rinsed with a dilute aqueous or aqueous-alcoholic dye solution. The dyes are generally cationic and are adsorbed by the hair surface they can mask the yellow color that results from bleaching or, given the proper selection of shade, can impart an attractive accent to the hair. Because of the short contact time with the hair, only slight color changes are possible. 

Figure 5-7. Penetration of a cationic surfactant into a split hair. Split hair treated with conditioner cross-sectioned and then stained with red 80 dye.

Figure 5-9. Light micrograph of a split hair treated with a cationic conditioner and then stained with red 80 dye. Note staining on all surfaces including the split surface (where the cationic conditioner adsorbs). Compare to Figure 5-8.

Liquid water at room temperature can penetrate across the entire fiber in less than 15min and in less than 5min at 92°F [76], whereas more than 6h is required for single hbers to equilibrate in a humid atmosphere, and even longer for a hber assembly. Dyes like methylene blue (MW 320) and orange II (MW 350) generally require over an hour to penetrate through the cuticle layers to the cortex. Similar penetration times would be expected for typical anionic and cationic surfactants used in shampoos and hair conditioners. 

In neutral dyeing or surfactant-hair interactions, competition of cations with hydrogen ions must play a role. When the concentration of hydrogen ions is low and cations of low affinity are present, the adsorption of anion is influenced by the concentration and affinity of cations for hair. If the cation affinity is high enough so that it is adsorbed, a counterion must accompany it to maintain electrical neutrality. In the presence of low-affinity cations... 

Figure 6-2. Illustration of ring dyeing. Cross sections of hair fibers treated with cetrimonium chloride for 1 h and then stained with Rubine dye after sectioning. The staining shows where the cationic surfactant had penetrated into the hair.

Primary valence bonds include ionic and covalent bonds and are the strongest binding forces. They generally have bond energies of approximately 50 to 200kcal/mole [17]. Ionic bonds are extremely important to the interactions of polymeric cationic ingredients and hair, whereas covalent bonds are probably involved between polymer and hair in certain in situ polymerization reactions or in the reaction of oxidation dyes with hair. 

Classification Quaternary ammonium salt Empirical CsiHssN Cl Properties M.w. 480.26 cationic Uses Surfactant, antistat in cosmetics textile softener, antistat, dyeing aid corrosion inhibitor emulsifier, softener, emollient in hair rinses, skin creams/lotions, pharmaceuticals Trade Name Synonyms Genamin KDB t[Clariant/Functional Chems.] Kemamine BQ-2802C [Crompton http //www. cromptoncorp. com]... 

Properties Solid m.w. 268.45 m.p. 38 C cationic Toxicology TSCA listed Uses Antistat, hair conditioner, surfactant in cosmetics, shampoos corrosion inhibitor, emulsifier, dispersant and fluidizing agent for pigments, emulsions, cosmetics, polishes, textiles, leather, and agric. prods. acid detergent for food and dairy prod intermediate for quat. ammonium compds. softener dye assistant... 

Uses Intermediate for cationic surfactants softener/antistat in hair conditioners germicide in foods, water treatment (duckweed killer), petroleum, textiles dispersant in paints antistat/disinfectant in plastics, pulp/paper dye leveling agent antimicrobial, preservative in foods, cosmetics antimicrobial in cane-sugar mills, pharmaceutical topicals organophilic surf, treatment agent in bentonite in food-pkg. adhesives... 

Electrophoretic techniques, mainly capillary zone electrophoresis (CZE) and also capillary iso-tachophoresis (ITP) or micellar electrokinetic chromatography (MEKC) have been used in cosmetic analysis (e.g., determination of cationic surfactants in toiletries, parabens in different cosmetics, fluoride, and polyphosphates in toothpaste, hair dyes, or acid preservatives in cosmetic lotions). However, their use is less extensive than LC, probably because the... 

Despite its limitations the dye method has the advantage of being very simple and sensitive. In early work Scott et al. utilized the dye rubine to disclose the presence of the cationic surfactant cetyltrimethylammoniirm bromide (CTAB) on hair (56). Actually, the hair was sectioned and the dye was able to show the (considerable) penetration of the surfactant into the hair, especially under alkaline conditions. In a later paper, Crawford and Robbins demonstrated the potential of Red 80 as a replacement dye for rubine (57) in disclosing both cationic surfactants and polymers. Unilever scientists, among others, have reported the use of the dye. Fast Bordeaux Red, to disclose the presence of Polymer JR on hair (58). 

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