Hydrophilic aliphatic polyurethane foams

A process for preparing hydrophilic aliphatic polyurethane foams wherein compositions comprising

• A) hydrophilic polyisocyanates obtainable by reaction of
• A1) low molecular weight aliphatic diisocyanates having a molar mass of 140 to 278 g/mol and/or polyisocyanates obtainable therefrom with an isocyanate functionality of 2 to 6, with
• A2) monofunctional polyalkylene oxides having an OH number of 10 to 250, and an ethylene oxide content of 50 to 100 mol % based on the total amount of oxyalkylene groups present,
• B) heterocyclic 4-ring or 6-ring oligomers of low molecular weight aliphatic diisocyanates having a molar mass of 140 to 278 g/mol,
• C) water,
• D) optionally catalysts,
• E) optionally C8 to C22 monocarboxylic acids or their ammonium or alkali metal salts or C12 to C44 dicarboxylic acids or their ammonium or alkali metal salts,
• F) optionally surfactants,
• G) optionally mono- or polyhydric alcohols, and
• H) no isocyanate-functional prepolymer having a weight fraction of low molecular weight aliphatic diisocyanates having a molar mass of 140 to 278 g/mol of below 1.0% by weight based on the prepolymer, obtainable by reaction of
• H1) low molecular weight aliphatic diisocyanates having a molar mass of 140 to 278 g/mol with
• H2) di- to hexafunctional polyalkylene oxides having an OH number of 22.5 to 112 mg KOH/g and an ethylene oxide content of 50 to 100 mol % based on the total amount of oxyalkylene groups present,
• are provided, foamed and cured.