| 摘要 |
The present invention relates to a process for producing viscoelastic flexible polyurethane foams having an air flow value of at least 1 dm3/s, which comprises (a) polyisocyanate being mixed with (b) polymeric compounds having isocyanate-reactive groups, (c) optionally chain-extending and/or crosslinking agents, (d) optionally compounds having only one isocyanate-reactive group with a hydroxyl number of 100 to 500 mg KOH/g, (e) catalyst, (f) blowing agent, and also optionally (g) addition agents to form a reaction mixture and convert it into flexible polyurethane foam, wherein the polymeric compounds having isocyanate-reactive groups (b) comprise 10 to 40 wt% of at least one polyalkylene oxide (b1) having a hydroxyl number of 90 to 300 mg KOH/g, based on a 3 to 6-functional starter molecule and a propylene oxide fraction, based on the alkylene oxide content, of 80 to 100 wt%, 5 to 20 wt% of at least one polyalkylene oxide (b2) having a hydroxyl number of 10 to 60 mg KOH/g, based on a 2 to 4-functional starter molecule and a propylene oxide fraction, based on the alkylene oxide content, of 80 to 100 wt%, 10 to 50 wt% of at least one polyalkylene oxide (b3) having a hydroxyl number of 10 to 55 mg KOH/g, based on a 2 to 4-functional starter molecule and an ethylene oxide fraction, based on the alkylene oxide content, of 70 to 100 wt%, and 0 to 20 wt% of at least one polyalkylene oxide (b4) having a hydroxyl number of 50 to 200 mg KOH/g, based on a 2-functional starter molecule and an ethylene oxide fraction, based on the alkylene oxide content, of 80 to 100 wt%, and wherein the fraction of compounds b1) to b4), based on the total weight of polymeric compounds having isocyanate-reactive groups (b), is at least 80 wt%. The present invention further relates to a viscoelastic polyurethane foam having an air flow value of at least 1 dm3/s, which is obtainable by such a process, and to the use of such a polyurethane foam for mattresses and cushions. |
