| 摘要 |
<p>The present invention relates to a hard polyurethane foam obtainable by mixing (a) isocyanates, (b) compounds with groups reactive toward isocyanates, (c) blowing agents comprising water, (d) catalysts and optionally (e) further additives to give a reaction mixture, applying the reaction mixture to a reinforcing means and hardening the reaction mixture, the isocyanates (a) having a viscosity of not more than 500 mPas at 25°C and the compounds having groups reactive toward isocyanates, (b) comprising a polyetherol (b1) having a functionality of 4 or greater and a viscosity at 25°C of 10 000 mPas or less, a polyetherol (b2) having a functionality of 3.5 or less and a viscosity at 25°C of 600 mPas or less, ein Polyesterol (b3) having a viscosity at 25°C of 2500 mPas or lower, chain extenders (b4) containing at least 30% secondary OH groups, and optionally a crosslinker (b5). The present invention further relates to a process for producing such rigid polyurethane foams and to the use of the rigid polyurethane foams for insulating liquid natural gas tanks.</p> |
