Considering hair styling, what could be more natural than simply combing or brushing hair? Or setting hair after shampooing and conditioning so that it dries in the desired style? In the latter case, wet hair is more flexible and deformable due to the hydrogen bonding of absorbed water with amino acids in the keratin protein fibers of the hair cortex. These bonds supplant the intermolecular bonds within the keratin itself, giving wet hair a malleability that allows simple styling without the need for styling additives. However, this hold is not very durable, especially in high humidity. The set relaxation time of simple water-styled coiffures depends on the relative humidity of the environment since it re-plasticizes the hair keratin. Hair care researchers have even devised mathematical formulas to define the process of curl set relaxation, which could be used to evaluate ingredients and formulations.
While water-set, comb-and-go hair styling is enough for some, many consumers want something more substantial. The style they worked hard to achieve should last until they touch-up or restyle hair. This is one performance property required in a styling product. Common hair styling aids to help hold hair in place encompass a wide range of products; from polymer solutions delivered as simple liquid or foamed into mousse, to gels of varying viscosities and film stiffnesses. The essential elements of a natural hair styling liquid or gel are: a film-forming substance to keep hair in place, and a base to deliver it. This base may be as simple as thickened water or as complex as a gel or cream.
Hair Hold Technologies
Within the last few decades of hair polymer advances, a veritable avalanche of ingredients to hold hair has been invented. Now available to choose from are more than 100 polyquaterniums, and dozens of vinyl pyrollidone, vinyl acetate, acrylate and other copolymers; terpolymers; and more complex polymers for hair styling. However, under the guidelines of major “natural” certifying groups—i.e., NSF/ANSI 305, Ecocert, COSMOS, NPA and NaTrue—all of these synthetic polymers would likely be unacceptable. Thus, the natural hair care formulator must look elsewhere for materials with which to work.
In this regard, manufacturers and their product development teams often look to a major U.S. retailer in this mass-market space: Whole Foods, whose strict standards reflect the guidelines of the major certifying groups but do not follow them exactly. Table 1 reveals some differences between ingredients that are acceptable for simple placement in the store and, in a more elite category, that fall under the stricter Premium Body Care banner closer to the natural certifiers’ standards. Here it becomes clear that many conventional styling aids could be found simply placed on Whole Foods shelves, but many traditional synthetic polymers, such as carbomer for gel formation and polyvinylpyrrolidone (PVP) for hold, do not meet the Premium Body Care standard.