| 摘要 |
The invention is directed to polyurethane rigid foams which can be prepared by reacting a) polyisocyanates with b) compounds having at least two hydrogen atoms which are reactive toward isocyanate groups in the presence of c) blowing agents and d) at least one flame retardant, wherein the compounds having at least two hydrogen atoms which are reactive toward isocyanate groups b) comprise at least one polyether polyol bi) and at least one polyester polyol bii) and the flame retardant d) comprises expandable graphite di). |
