Linear Polyethylenes and Long-Chain Alcohols in Underarm Sticks and Soft Solids

By: Allison Hunter and Melanie Trevino, New Phase Technologies

Posted: April 27, 2006, from the December 2003 issue of Cosmetics & Toiletries.

In today’s increasingly competitive personal care market, formulators of underarm products need technologies that can help them deliver novel and aesthetically pleasing product forms to consumers – while at the same time satisfying manufacturing needs for easy formulating and cost efficiency.

Stearyl alcohol is a common gelling agent for antiperspirant sticks and gels. However, new technological developments allow formulators to use lower quantities of totally linear polyethylenes and linear, long-chain alcohols (in the range of C20 to C50, compared to C18 for stearyl alcohol) as gellants.

Although other long-chained materials exist, the completely linear form of the polyethylenes and alcohols is distinctive and makes these polymers more crystalline than branched polymers or shorter-chain polymers. Using these materials allows more flexibility in formulation because less gellant is required, and the ultimate structure is characterized by a latticework of smaller crystals than those associated with other gellants. This structure can improve formulation aesthetics as well as enhance the distinctive sensory properties of cyclomethicone to give soft, dry and smooth application without drag. In addition, the smaller crystal size improves stability of the final formulation.

This article describes these linear polyethylenes and their corresponding long-chain alcohols, compares their gelling efficiency and stability with that of stearyl alcohol and uses microscope photographs to illustrate their crystalline characteristics. In addition, a prototype formulation demonstrates use of the materials in a soft solid product form.

This is only an excerpt of the full article that appeared in Cosmetics & Toiletries, but you can purchase the full-text version.