2008 TRI/PRINCETON CONFERENCE 227 without PQ-55. The color difference of the two tresses determined by the panel test is within the range from slight to moderate under the three light source used. Therefore, the color protection effect of PQ-55 leave-in treatments is perceivable by the naked eye. Rinse-off treatment with PQ-55 shampoo and conditioner products. The effect of PQ-55 on hair color protection was evaluated in a rinse-off shampoo (Table III) and conditioner formula. The formula for the conditioner is based on a blend of hydroxyethyl cetearami- dopropyldimonium chloride and stearamido propyl dimethylamine as conditioning agents in cream base thickened with fatty alcohols and nonionic surfactants. Figure 8a shows the color fading test results of dyed bleached hair samples washed with a shampoo containing 0.5% PQ-55 against the control, 12% SLES. The result indicates that 0.5% PQ-55 in the shampoo formula provides 21% color retention over the SLES control after 10× washes and the effect is visible by eyes. Figure 8b shows the color fading Figure 4. Chemical structures of selected polymers with/without hydrophobic chain and/or quaternization. Figure 5. Pictures and color loss of dyed hair samples after 10× SLES washes and leave-in treatment of 2% polymers, intense red colored hair, dyed bleached dark brown hair.

JOURNAL OF COSMETIC SCIENCE 228 test results of dyed bleached hair treated with the PQ-55 conditioner against the same conditioner but to which PQ-55 was not added, using 12% SLES as a washing agent for both the tested and the control hair tresses. There is limited color protection benefi t by using the conditioner formula alone. This is due to the negative effect of cationic surfac- tant on hair color fading as described in the previous section which balances off the color protection effect of PQ-55. Combination of PQ-55 leave-in treatment with rinse-off treatment. Figure 9 shows the anti-fading test results and pictures of dyed hair samples after combined treatment of 2% PQ-55 leave-in gel and 0.5% PQ-55 shampoo against the treatment with the same gel formula but without PQ-55 in it and 12% SLES washes. The PQ-55 combined anti- fading system achieves as high as 50% color protection over the control. Figure 6. Color loss of dyed hair samples after 10× SLES washes and leave-in treatment of PQ-55 and HEC derivatives, intense red colored hair, dyed bleached hair. Figure 7. (a) Color loss of dyed bleached hair samples with and without 2% PQ-55 leave-in treatment, in- tense red colored dye, 12% SLES as washing agent. (b) Subjective panel test results after 10× washes and treatment.