| abstract |
The invention relates to a method for producing viscoelastic polyurethane flexible foam materials by converting a) polyisocyanates with b) compounds having at least two hydrogen atoms reactive with isocyanate groups, and c) blowing agents, characterized in that the compounds having at least two hydrogen atoms reactive with isocyanate groups b) comprise b1) 0 to 90 parts by weight of at least one polyether alcohol made of exclusively propylene oxide units or propylene oxide units and a maximum of 50% by weight, relative to the total amount of alkylene oxide ethylene oxide units used in the polyether chain, having a nominal functionality of 3-8 and a hydroxyl number in the range of 100 to 350 mg KOH/g, and b2) 10 to 100 parts by weight of at least one graft polyol that can be produced by in situ polymerization of olefinically unsaturated monomers in at least one polyether alcohol comprising exclusively propylene oxide units or propylene oxide units and a maximum of 50% by weight, relative to the total amount of the alkylene oxide ethylene oxide units in the polyether chain, having a nominal functionality of 2-8 and a hydroxyl number in the range of 100 to 350 mg KOH/g, having a solids content of a maximum of 60% by weight, relative to the total amount of the polyols and solids used, the sum of the parts by weight b1) and b2) being 100. |