Patent ID: 8426482

Claim:
A process for producing a viscoelastic flexible polyurethane foam, comprising: reacting a) at least one polyisocyanate with b) compounds having at least two hydrogen atoms which are reactive toward isocyanate groups, in a mixture comprising bi) from 25 to 70% by weight of castor oil, based on a weight of components bi), bii), biii), and biv), bii) from 3 to 30% by weight, based on the weight of the components bi), bii), biii), and biv), of at least one first 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 prepared by addition of at least one alkylene oxide onto an amine, biii) 20-50% by weight, based on the weight of the components bi), bii), biii), and biv), of at least one second polyether alcohol which has a hydroxyl number of from 10 to 80 mg KOH/g and a functionality of from 2 to 5 and is prepared by addition of ethylene oxide and propylene oxide onto at least one H-functional starter substance, where a proportion of ethylene oxide is 5-25% by weight, based on a weight of the polyether alcohol, and at least part of the ethylene oxide is added on at an end of a chain the second polyether alcohol, biv) >0-5% by weight, based on the weight of the components bi), bii), biii), and biv), of at least one third polyether alcohol having a functionality of 2-4, a hydroxyl number of 15-60 mg KOH/g, and a content of ethylene oxide of >50% by weight, based on the weight of the third polyether alcohol.