Intensively bleached hair 2006 TRI/PRINCETON CONFERENCE 349 Semi-permanent Dye Dye Color Color measurement measurement 5% PCA Water Wash i\E Figure 1. Experimental design of Test I. 4-amino-3-nitropheol by immersing in the 0.02 wt% solution for 30 minutes. After removal from the dye solution, the swatches were air dried. Treatment with PCA solutions and color measurement: The pH of 5.0 wt% PCA or citric acid solution was adjusted with arginine. A hair swatch was immersed in 6 ml of the solution for 30 minutes. Treatment in deionized water was set as control. The swatch was rinsed in running tap water for 20 seconds and air dried overnight. The color value was measured by a colorimeter (initial value). The swatch was immersed in 6 ml deionized water for 30 minutes, air dried overnight, and the color value was measured again (after wash). Relative BE* was determined as following in order to eliminate the variance among each experiment: Relative .6.E* = LiE*/LiEzonrrnl Test II (Figure 2) • Hair dye: Red shade. The dye component was the emulsion formula based on fatty alcohols and contained following dye precursors and direct dyes Toluene-2,5-diamine sulfate, 2-Methylresorcinol, 4-amino-2-hydroxytoluene, 4-Amino-3-nitrophenol, 6 .. Post-dye Shampoo Shampoo Treatment x3times Conditioner x3times Conditioner Color Shampoo Conditioner Shampoo Color Dye treatment I measurement measurement 'n q A Initial value A A q A q after 6 cycles i::::::: B B B i::::::: B i::::::: i::::::: C C C C i::::::: i::::::: D D D D i::::::: Shampoo Shampoo Conditioner x3 times Conditioner x3times Conditioner Shampoo Conditioner Shampoo Color measurement q A A q A A after 6 cycles i::::::: B B i::::::: B B i::::::: C C i::::::: C C i::::::: D D i::::::: D c:::::: D Figure 2. Experimental design of Test II.

2006 TRI/PRINCETON CONFERENCE 351 Table lb Shampoos Used in Test II A B C D Control Sodium PCA Sodium PCA + Arg Silicone Na Laureth sulfate (active) 7.56 7.56 7.56 7.56 Cocamilopropyl betaine (active) 1.20 1.20 1.20 1.20 Sodium PCA 2.00 1.00 Arginine 0.40 Amodimethicone, emulsion 2.00 Pearlizing agent 4.00 4.00 4.00 4.00 Preservatives q.s q.s q.s q.s NaCl 2.00 2.00 2.00 2.00 Citric acid pH 5.8 pH 5.8 pH 5.8 pH 5.8 Water Balance Balance Balance Balance 10.0 a, 'i:" � ·- ca ra 5.0 +,I .c Q. I ::J .EJ en o L. 0.0 c( :::L 3 6 9 -5.0 pH value Figure 3. Arg uptake at various pH. Hair: Arg: 5.741 mM, 10 minutes immersion, 40°C. Arg Gly Ci) H3 N+ �� oW coo- Glu Hair pH 3 pH 6 pH 9 Figure 4. Ionic charge on amino acids and hair at various pH.