VASKBARE, VISKOELASTISKE BLØDE POLYURETHANSKUMSTOFFER

Producing viscoelastic polyurethane soft foam material having an air permeability of at least 1 dm 3>/second, comprises mixing and reacting (a) polyisocyanate with (b) polymeric compounds having groups reactive with isocyanate, (c) optionally chain extenders- and/or crosslinking agents, (d) optionally compounds having only one group reactive with isocyanates and having a hydroxyl number of 100-500 mg potassium hydroxide/g, (e) catalyst, (f) blowing agents and (g) optionally additives, to obtain a reaction mixture. Producing viscoelastic polyurethane soft foam materials having an air permeability of at least 1 dm 3>/second, comprises mixing and reacting (a) polyisocyanate with (b) polymeric compounds having groups reactive with isocyanate, (c) optionally chain extenders- and/or crosslinking agents, (d) optionally compounds having only one group reactive with isocyanates and having a hydroxyl number of 100-500 mg potassium hydroxide/g, (e) catalyst, (f) blowing agents and (g) optionally additives, to obtain a reaction mixture. The polymeric compounds have groups (b) reactive with isocyanates include: (b1) 10-40 wt.% at least one polyalkylene oxide having a hydroxyl number of 90-300 mg potassium hydroxide/g, starting from an 3-6-functional initiator molecule, and 80-100 wt.% propylene oxide fraction, based on the amount of alkylene oxide; (b2) 5-20 wt.% at least one polyalkylene oxide having a hydroxyl number of 10-60 mg potassium hydroxide/g, based on an 2-4-functional initiator molecule, and 80-100 wt.% propylene oxide fraction, based on the amount of alkylene oxide; (b3) 10-50 wt.% at least one polyalkylene oxide having a hydroxyl number of 10-55 mg potassium hydroxide/g, based on an 2-4-functional initiator molecule, and 70-100 wt.% ethylene oxide fraction, based on the amount of alkylene oxide; and (b4) 0-20 wt.% at least one polyalkylene oxide having a hydroxyl number of 50-200 mg potassium hydroxide/g, based on an 2-functional initiator molecule, and 80-100 wt.% ethylene oxide fraction, based on the amount of alkylene oxide, where the proportion of the compounds (b1) to (b4) is at least 80 wt.%, based on the total weight of the polymeric compounds having groups (b) reactive with respect to isocyanates. An independent claim is also included for the viscoelastic polyurethane soft foam material obtainable by the above mentioned method.