Stepan Chemical, Chicago, IL, produces a secondary surfactant for cleansing products such as shampoos and body washes called Amphosol CDB Special (INCI name: Cetyl betaine). This clear liquid is 30% active with 37% solids and contains no dioxane, PEG or EO/PO. It is readily biodegradable, made from natural fatty methyl esters, can be mixed cold, and has a Biorenewable Carbon Index (BCI) of 78. The BCI is derived by dividing the number of biorenewable carbons by the total carbons in the idealized molecule times 100. Biorenewable materials originate from animal-, plant- or marine-based sources.
Tests were run using Amphosol CDB Special with various sulfate-free surfactants to determine the amount of sodium chloride necessary to increase the viscosity of the mix. The greatest increase of viscosity occurred with the mixture of CDB and sodium C14-16 16 olefin sulfonate, where the viscosity started to rise at about 0.4% salt and reached a maximum of 30,000cps with 2% salt. The mixture of CDB and sodium lauryl sulfoacetate, disodium laureth sulfosuccinate (LSB) reached 20,000cps with about 1.5% salt but when more salt was added, the viscosity began dropping and 2% salt gave a viscosity of about 15,000cps. With sodium laureth sulfate (the control), the viscosity started to rise at 1% salt to a maximum of about 24,000cps with 2% salt.
A shake-foam test was done using a 0.2% active solution of the surfactants and tap water with and without castor oil. Mildness was measured by calculating the amount of Zein protein solubilized in a 1% active surfactant solution as compared to sodium lauryl sulfate (SLS). The less protein solubilized, the milder the surfactant. SLS alone solubilized the most protein; the mixture of CDB and LSB dissolved the least amount of protein.
Sodium methyl-2-sulfolaurate, disodium 2-sulfolaurate27.00
Amphosol CDB Special15.13
Lauryl lactyl lactate0.50
Sodium lauroyl lactylate0.50
Linium usitatissium extract (Flax) 0.25
Preservative, dye, and citric acidq.s.
Procedure:Begin heating water in main vessel. With constant stirring, add the first four ingredients and the glycol stearate while heating to 60-65°C. Mix for 30 minutes, begin cooling to 40°C and add the collagen, flax extract, panthenol and polyquaternium 7. Cool to 25°C to adjust the pH with citric acid or sodium hydroxide, if necessary. Add preservative, dye, and fragrance as needed.
The above is a pearlized viscous liquid, ph 5.0-5.5, and a viscosity at 25°C of 5500 to 6500 cps.
The simple body wash below is also sulfate-free.
Sulfate-Free Body Wash
Sodium methyl-2-sulfolaurate, disodium 2-sulfolaurate 16.22
Amphosol CDB Special13.32
Kathon CG (preservative)0.05
Citric acid or sodium hydroxide (25%) q.s.
Procedure: To water in tank, with constant stirring, add Polyquaternium 7 and mix until dissolved and solution is clear. Add first two ingredients, then glycerine. When homogeneous, add fragrance, dye and preservative and mix well. Adjust pH. Viscosity may be adjusted with sodium chloride if needed.
This is a clear, viscous liquid with a viscosity of 7,000 to 9,000 cps and a pH of 5.2 – 5.8.
Harvey Fishman has a consulting firm located at 34 Chicasaw Drive, Oakland, NJ 07436, firstname.lastname@example.org, specializing in cosmetic formulations and new product ideas, offering tested finished products. He has more than 30 years of experience and has been director of research at Bonat, Nestlé LeMur and Turner Hall. He welcomes descriptive literature from suppliers and bench chemists and others in the field.