EVALUATION OF HAIR FIXATIVES 71 0 1.0 20 30 40 50 60 70 TIME (MINUTES) Figure 5. Pickup measurements by strain gauge apparatus. Fixative solution deposited on hair swatch (milligrams) vs. time the solvent evaporation rate was constant over the first part of the drying curve, extrapolation of the curve yielded a wet solution pickup weight (W.0. Resin pickup was determined by the following formula: WsS Resin Pickup (%) - x 100 (III) Wh Ws = weight (grams) of solution picked up S = per cent fixative solids (by weight) in the test solution Wh = weight (grams) of swatch 80 70 •40 30 o o5 lo 1.5 20 3.0 40 50 TIME (HOURS) ß RESIN C2 RESIN 0 RESIN A ß RESIN fl / / r 21 o Figure 6. Curl Retention Analysis--Set I--Average curl retention (per cent) as a function of time (hours) for 2 per cent solutions of Resin A, B, C, D and E at 90 percent R.H., 22øC

72 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS 90 30 •0 0 050 10 20 30 40 TIME (HOURS) 7o • 5o _• •o o• FORMULATION E1 FORMULA TION E2 ß RESIN E FORMULATION D1 RESIN O Figure 7. Curl Retention Analysis--Set II--Average curl retention (per cent) as a function of time (hours) for 2 per cent solutions of Resins D, E and Formulations D1, El, E2 at 90 per cent R.H., 22øC 20 RESIN A RESIN 0 10 20 30 40 50 60 70 80 90 100 110 120 TIME (MINUTES) Figure 8. Twist Retention Analysis--Set I--Average Twist Retention as a function of time (minutes) for Resin A, B, C, D, and E at 90 to 93 per cent R.H., 21 to 25øC, and 2 per cent fixative solids (0.19 per cent pickup)