The use of a mixture b in a flexible polyurethane foam, wherein the mixture b comprises the following components: b1) 75 to 94% by weight of at least one polyether polyol having a hydroxyl value of 10 to 60 mg KOH/g, an OH functionality of more than 2, and ethylene oxide in a proportion of 50 to 100% by weight based on the content of alkylene oxide, b2) 3 to 20% by weight of at least one polyether polyol having a hydroxyl value of 10 to 100 mg KOH/g, an OH functionality of more than 2, ethylene oxide in a proportion of 2 to 30% by weight based on the content of alkylene oxide, and a proportion of primary OH groups of 40 to 100% based on the total number of OH groups in component b2), b3) 3 to 20% by weight of at least one polyether polyol having a hydroxyl value of 10 to 100 mg KOH/g, an OH functionality of more than 2, ethylene oxide in a proportion of 0 to 30% by weight based on the content of alkylene oxide, and a proportion of primary OH groups of 0 to 30% based on the total number of OH groups in component b3), in each case based on the total amount by weight of components b1) to b3), which comes to 100% by weight, and b5) from 0.25 to 10 further parts by weight of polyurea, based on 100 parts by weight of components b1) to b3), optionally present as a constituent of a dispersion polyol based on one or more of components b1) to b3), and also b4) from 0 to 10 further parts by weight, based on 100 parts by weight of components b1) to b3), of at least one further polyether polyol that differs from components b1) to b3), and b6) from 0 to 15 further parts by weight of filler, based on 100 parts by weight of components b1) to b3), optionally present as a constituent of a graft polyol based on one or more of components b1) to b3). b1) 75 to 94% by weight of at least one polyether polyol having a hydroxyl value of 10 to 60 mg KOH/g, an OH functionality of more than 2, and ethylene oxide in a proportion of 50 to 100% by weight based on the content of alkylene oxide, b2) 3 to 20% by weight of at least one polyether polyol having a hydroxyl value of 10 to 100 mg KOH/g, an OH functionality of more than 2, ethylene oxide in a proportion of 2 to 30% by weight based on the content of alkylene oxide, and a proportion of primary OH groups of 40 to 100% based on the total number of OH groups in component b2), b3) 3 to 20% by weight of at least one polyether polyol having a hydroxyl value of 10 to 100 mg KOH/g, an OH functionality of more than 2, ethylene oxide in a proportion of 0 to 30% by weight based on the content of alkylene oxide, and a proportion of primary OH groups of 0 to 30% based on the total number of OH groups in component b3), in each case based on the total amount by weight of components b1) to b3), which comes to 100% by weight, and b5) from 0.25 to 10 further parts by weight of polyurea, based on 100 parts by weight of components b1) to b3), optionally present as a constituent of a dispersion polyol based on one or more of components b1) to b3), and also b4) from 0 to 10 further parts by weight, based on 100 parts by weight of components b1) to b3), of at least one further polyether polyol that differs from components b1) to b3), and b6) from 0 to 15 further parts by weight of filler, based on 100 parts by weight of components b1) to b3), optionally present as a constituent of a graft polyol based on one or more of components b1) to b3).