Use as thickeners in cosmetics of neutralized copolymers comprising weak acid units and strong acid units, and cosmetic compositions comprising same

摘要

This invention relates to a cosmetic, dermatologic, pharmaceutical, or veterinary composition comprising at least one thickening and/or emulsifying polymer for an aqueous medium, such composition being obtained by polymerization: at least one unsaturated weak acid and at least one unsaturated strong acid such as AMPS, in the presence of a cross-linking or branching agent and optionally of a transfer agent and characterized by a water-soluble polymer fraction ranging from 5 to 50 percent by weight, preferably 8 to 35 percent. These acids are partially neutralized at the time of polymerization. The composition obtained surprisingly exhibits optimal cosmetic characteristics, in particular very high stability in the presence of electrolytes over a very wide pH range (1-13) as a result of selection of suitable polymerization conditions for the thickening and/or emulsifying polymer (neutralization rate, active matter concentration, strong/weak acid molar ratio).