Pigment wetting and skin moisturization are two of the many desirable functions esters impart to cosmetic formulations, but there are more. The chemist has a choice of more than 3,000 esters that deliver one or more of nine functions (see sidebar), but no one ester delivers all of these functions. So how does the chemist choose one ester from so many? In this article we discuss one ester that provides pigment wetting and skin moisturization – two functions that are useful in a wide range of personal care products.
Polymeric Ester Containing Essential Fatty Acids Polymeric esters have found applications in personal care products for many years. Today they are produced by several companies, including Arch Personal Care Products, Trivent Chemicalsa, ExxonMobil and others.
While polymeric esters all share the common characteristic of one or more bonds formed between carboxylic acid groups and hydroxyl groups, they vary considerably in their polymeric structures and molecular weights. Some are polymeric by virtue of incorporating polyoxyethylene or polyoxypropylene chains in their structures, while others are polymeric due to the presence of polymerized polyols. These differences produce polymeric esters with greatly varying degrees of emolliency, lubricity, viscosity and spreadability.
Because of the various structural configurations of polymeric esters, the methods of producing them are equally various. In general, one method involves the formation of the polymeric alkoxylate or polymerized polyol, followed by catalytic esterification with monobasic, dibasic or polybasic carboxylic acids. Again, many other methods are available because of the infinite polymeric configurations of these types of esters.
