Abstract: The invention relates to stable emulsions for the production of foams based on isocyanates, comprising at least three polyols A1a, A1b and A1c and at least one physical blowing agent T, wherein A1a is a polyether polyol, obtained by the addition of epoxies to starter compounds selected from carbohydrates and difunctional or higher-functional alcohols, A1b is a polyether polyol started on an aromatic amine and A1c is a polyester polyether polyol, obtained by the addition of epoxies to the esterification product of an aromatic dicarboxylic acid derivative and a difunctional or higher-functional alcohol. The invention further relates to a method for producing foams by reactions of such emulsions with isocyanates and to the foams obtainable in this way and their use for insulating purposes.