PROPERTIES OF ETHOXYLATED LANOLIN Table I Clear Gel Shampoo 525 W/W% Cocamide 10.00 TEA Laury] Sulfate 50.00 Linoleamide DEA 5.00 EDTA 0.50 Methy]garaben 0.20 Deionized Water 34.30 100.00 dehyde type D-terpenes, esters, and resins and type E-ester, alcohol ter- pene. The solutions were prepared at room temperature by first blending the fra- grance into the solubilizer and adding this to the water/alcohol mixture with agitation. (The Laneth-16 and PEG-75 Lanolin were heated slightly to con- vert them to liquids.) This resultcd in 40 solutions, which were tested for stability at room temperature and 105øF for a period of 1 month. E. Viscosity study on a gel shampoo-the following ethyoxylates were test- ed at 1, 5, 10, and 20 per cent levels in a gel shampoo: (1) PEG-75 Lanolin Oil (2) PEG-75 Lanolin (3) Laneth-40 (4) Laneth-16 (5) PEG-g4 Hydro- genated Lanolin (6) PEG-75 Lanolin Wax (7) Laneth-5 * and (8) Laneth- iO Acetate. In preparing the gel shampoo, all of the ingredients in Table I were charged in order and heated with mixing to 75øC. The shampoo was then cooled slowly to 55 øC. The gel formed was further cooled slowly to 30øC. In the experimental shampoos prepared with the ethoxylates, an equivalent amount of aleionized water was removed from the formula. All the raw ma- terials used were taken from the same batch in order to minimize any slight differences found in their analytical specifications. Viscosities were taken ini- tially and then weekly for 2 months. Records of specific gravity and stability were made during this period. DISCUSSION OF RESULTS Saad and Shay (2) described cmc as that point or range at which the con- stitution of the surfactant solute changes from a disperse state to an equilib- rium between molecules (or ions) and aggregates (micelies). It has been noted that properties such as surface tension show an abrupt change at the cmc. Table II illustrates this change. For example, one notices a decreasing *Ethoxyol 5 Maimstrom Chemical Corp., Linden, N.J.

526 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Table II CMC Determination Using Surface Tension Data Surface Tension (dyn/cm) Concentration PEG-75 PEG-75 PEG-75 Laneth-16 (% Wt) Lanolin Lanolin Lanolin Wax Oil PEG-24 Hydrogenated Laneth-40 Laneth-10 Lanolin Acetate 0.025 52 -- 69 65 -- 68 48 0.05 49 59 66 62 58 65 48 0.10 48 58 65 60 55 63 43 0.15 45 57 63 59 54 63 42 0.20 44 58 61 58 57 65 40 0.25 44 59 63 59 57 67 40 0.50 47 59 67 60 59 69 38 1.00 50 59 68 60 59 69 40 •mc(%Wt) 0.20% 0.15% 0.20% 0.20% 0.15% 0.10% 0.20% 16- 12- 8- MW CMC CMC g/100ml Moles/100ml X 10 '5 'x%• I-aneth'16 Laneth-16 990 0.10 20.5 PEG-24 Hydrol•enated I.anolin 1310 0,20 11.5 • I.aneth-5.10.101950 • PEG-24 Hydr9•enated Laneth-40 1000 1250 1500 A750 2000 MOLECULAR WEIGHT Figure I. Molar cmc versus molecular weight trend in the surface tension as the concentration of Laneth-16 increases up to 0.20 per cent. Then the surface tension suddenly increases as the concentra- tion is further increased. The point at which this change takes place is noted as the cmc and is so designated on the bottom line of the table. Furthermore,