Some of the most useful thickeners for aqueous systems are cellulose derivatives. They also furnish other qualities. In the construction industry, they control the water binding ability of cement, gypsum and fillers. They perform the same function in wallpaper paste. As additives in laundry detergents, they prevent graying and discoloration. As thickeners in the food industry, they enhance composition, form, structure and consistency. In tablets in pharmaceuticals, they are binding agents and help release the active ingredients. Of course, cellulose derivatives are widely used as thickeners in the cosmetic industry.

The chart at right shows how some cellulose ether derivatives are created and their water solubility.

In cosmetics, cellulose derivatives can be used in both shampoos and conditioners. In shampoos, besides providing viscosity, they boost and stabilize foam and add a creamy texture to formulations. They are stable in salt and cationic solutions, increase viscosity across a broad pH range and allow the use of little or no salt. In conditioning systems, they become viscous in the aqueous phase through hydrogen bonding. The products are pseudoplastic, spread easily and rinse off easily from the hair. Cellulose derivatives can also help to stabilize emulsions.

AkzoNobel, Bridgewater, NJ, manufactures the cellulose derivatives listed below. The number after the name denotes the typical viscosity of a 1% solution in water.

*Structure Cel 12000 M
Methyl Hydroxyethyl Cellulose

Structure Cel 4400 E
Ethyl Hydroxyethyl Cellulose

Structure Cel 500 HM
C12-16 Alkyl PEG-2 Hydroxypropyl
Hydroxyethyl Ethylcellulose

*This is also available in a lower viscosity 8000 M grade.

An example of its use in hair products follows:

Sulfate-Free Shampoo

Procedure: Stir constantly. Mix first three ingredients in tank. Slowly sift in Structure Cel and heat to 40°C. When hydrated, cool to room temperature and add last ingredient. This yellow product is clear to slightly hazy, has a pH of 6-7, and a viscosity of 18,000 to 22,000 cps.

Harvey Fishman has a consulting firm located at 34 Chicasaw Drive, Oakland, NJ 07436, [email protected], 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.