ABSTRACT
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Oil phase materials are of interest to the cosmetic chemist in a variety of applications, including in pigmented products. These materials function as potential oils in which pigments may be ground, or oil phases used in emulsions. The type of products that are useful include poly alpha olefin (PAO), esters, Guerbet alcohols, and mineral oils (all of which are discussed in a separate chapter). The selection of the proper material for use depends upon many factors, one of which is the polarity of the oil. PAO and mineral oils are very nonpolar. The introduction of an oxygen, if either a hydroxyl group or an ester group, increases the polarity of the oil. The selection of a more polar oil for the creation of a pigment dispersion can be highly desirable in many instances, because the pigment can be considered a polar material. All chemistry students remember being admonished that likes dissolve likes. The negative attribute of using esters is that the materials can be hydrolytically unstable, breaking down at a pH of below 5 or over 10. This chapter deals with a new class of esters that are hydrolytically stable. This allows the formulator the ability to chose the polarity of the oil phase to optimize dispersion particle size and stability.
