Polyurethane polyurea, method for producing same and cosmetic composition containing same

The purpose of the present invention is to provide an additive having high thickening/gelatinizing effect, which is capable of thickening/gelatinizing silicone oils and ester oils with a small addition amount. In order to achieve the above-described purpose, the present invention provides, as the additive, a polyurethane polyurea which is obtained by reacting: a polyurethane polyurea prepolymer that is obtained from a silicone derivative starting material having a specific structure, a specific diisocyanate compound starting material and a starting material that is composed of a compound represented by general formula (C), said starting materials being respectively set forth in the description; and a nitrogen compound having a specific structure and/or a hydroxyl group-containing compound having a specific structure, said compounds being respectively set forth in the description. (In the formula, R30 represents an oxygen atom or a divalent hydrocarbon group having 1-10 carbon atoms; and y represents a number of 0 or 1. In cases where R30 is a divalent hydrocarbon group having 1-10 carbon atoms, y represents a number of 1, and in cases where R30 is an oxygen atom, y represents a number of 0.)