Abstract: Invention relates to a process for producing viscoelastic flexible polyurethane foams by reacting a) polyisocyanates with b) compounds having at least two hydrogen atoms which are reactive toward isocyanate groups, wherein as b) a mixture of bi) from 25 to 70% by weight of a hydroxyl-comprising natural oil or fat or a reaction product of a hydroxyl-comprising natural oil or fat with alkylene oxides, bii) from 3 to 30% by weight of at least one polyether having a hydroxyl number of from 100 to 800 mg KOH/g and a functionality of 3-5 selected from the group consisting of polyether prepared by addition of alkylene oxides onto an amine, biii) 20-50% by weight of at least one polyether alcohol having a hydroxyl number of from 10 to 80 mg KOH/g and a functionality of 2-5, where the proportion of ethylene oxide is 5-25% by weight, based on the weight of the polyether alcohol, and at least part of the ethylene oxide is added on at the end of the polyether chain, biv) >0-8% by weight of at least one polyether alcoh

Abstract: The invention relates to a process for producing viscoelastic flexible polyurethane foams by reacting a) polyisocyanates with b) compounds having at least two hydrogen atoms which are reactive toward isocyanate groups, wherein a mixture of bi) from 25 to 70% by weight, based on the weight of the components bi), bii), biii) and biv), of a hydroxyl-comprising natural oil or fat or a reaction product of a hydroxyl-comprising natural oil or fat with alkylene oxides, bii) from 3 to 30% by weight, based on the weight of the components bi), bii), biii) and biv), of at least one polyether alcohol which has a hydroxyl number of from 100 to 800 mg KOH/g and a functionality of from 3 to 5 and is selected from the group consisting of polyether alcohols prepared by addition of alkylene oxides onto an amine, biii) 20-50% by weight, based on the weight of the components bi), bii), biii) and biv), of at least one polyether alcohol which has a hydroxyl number of from 10 to 80 mg KOH/g and a functionality of from 2 to 5 and

Abstract: Flexible polyurethane foams are prepared by reacting organic and/or modified organic polyisocyanates (a) with a polyetherol mixture (b) and, if required, further compounds (c) having hydrogen atoms reactive toward isocyanates, in the presence of water and/or other blowing agents (d), catalysts (e) and, if required, further assistants and additives (f), by a process in which the polyetherol mixture (b) consists of b1) at least one polyetherol which is at least difunctional, has an OH number of from 20 to 100 mg KOH/g and is based on propylene oxide and/or butylene oxide and ethylene oxide, having an ethylene oxide content of more than 40% by weight, based on the total amount of alkylene oxide used, and, if required, further polyetherols which are at least difunctional, are based on propylene oxide and/or butylene oxide and ethylene oxide and have an OH number of from 20 to 160 mg KOH/g and b2) at least one difunctional to hexafunctional polyetherol based on propylene oxide and/or butylene oxide and having an

Abstract: Flexible polyurethane foams are prepared by reacting organic and/or modified organic polyisocyanates (a) with a polyetherol mixture (b) and, if required, further compounds (c) having hydrogen atoms reactive toward isocyanates, in the presence of water and/or other blowing agents (d), catalysts (e) and, if required, further assistants and additives (f), by a process in which the polyetherol mixture (b) consists of