A process for producing a hydrophilic flexible polyurethane foam, in which (a) at least one polyurethane prepolymer having an isocyanate content of 6 to 10% by weight, based on the weight of the isocyanate prepolymer (a), is mixed with (b) at least one aqueous component in a ratio by weight of polyurethane prepolymer (a) to aqueous component (b) from 3:1 to 1:1.2 and allowed to react to form the flexible polyurethane foam, wherein the polyurethane prepolymer (a) is obtainable by mixing and reacting at least one isocyanate (a1) with at least one polyetherol (a2), the isocyanate (a1) comprises methylenediphenylene diisocyanate and the polyetherol (a2) has a hydroxyl number of 30 to 60 mg KOH/g and is obtainable by alkoxylating at least one difunctional and/or trifunctional starter molecule with ethylene oxide and propylene oxide and the ethylene oxide content, based on the total weight of alkylene oxide, is at least 60% by weight, based on the total weight of the polyether polyol (a2), wherein the polyetherol (a2) is obtainable by propoxylation of the starter molecule(s) in a first step up to a hydroxyl number of 400 to 1200 mg KOH/g, followed by an alkoxylation of the propoxylated starter molecule with a mixture of ethylene oxide and propylene oxide and finally an ethoxylation of the alkoxylation product thus obtained with 2 to 10% by weight ethylene oxide, based on the alkylene oxide used for producing the polyetherol (a2), and the aqueous component (b) comprises at least 90% by weight water (b1) and up to 10% by weight non-silicone-containing surface-active substances (b2), based in each case on the total weight of component (b) . (a) at least one polyurethane prepolymer having an isocyanate content of 6 to 10% by weight, based on the weight of the isocyanate prepolymer (a), is mixed with (b) at least one aqueous component in a ratio by weight of polyurethane prepolymer (a) to aqueous component (b) from 3:1 to 1:1.2 and allowed to react to form the flexible polyurethane foam, wherein the polyurethane prepolymer (a) is obtainable by mixing and reacting at least one isocyanate (a1) with at least one polyetherol (a2), the isocyanate (a1) comprises methylenediphenylene diisocyanate and the polyetherol (a2) has a hydroxyl number of 30 to 60 mg KOH/g and is obtainable by alkoxylating at least one difunctional and/or trifunctional starter molecule with ethylene oxide and propylene oxide and the ethylene oxide content, based on the total weight of alkylene oxide, is at least 60% by weight, based on the total weight of the polyether polyol (a2), wherein the polyetherol (a2) is obtainable by propoxylation of the starter molecule(s) in a first step up to a hydroxyl number of 400 to 1200 mg KOH/g, followed by an alkoxylation of the propoxylated starter molecule with a mixture of ethylene oxide and propylene oxide and finally an ethoxylation of the alkoxylation product thus obtained with 2 to 10% by weight ethylene oxide, based on the alkylene oxide used for producing the polyetherol (a2), and the aqueous component (b) comprises at least 90% by weight water (b1) and up to 10% by weight non-silicone-containing surface-active substances (b2), based in each case on the total weight of component (b) . <EOS>