Patent ID: 6071978
Filing Date: 2000-06-06
Classification: C08G,C08J

Abstract:
A process for preparing polyurethane rigid foams from polyols and polyisocyanates as well as blowing agents and optionally foam auxiliary agents, characterised in that the polyurethane rigid foam is obtained by reactingA) a polyol component with on average at least 3 hydrogen atoms, containing1. 60 to 100% of polyethers and/or polyesters with at least 2 hydroxyl groups and a molecular weight of 250 to 1,500, which have a surface tension of 6 to 14 mN/m with respect to i-pentane and/or n-pentane as blowing agent, wherein the polyethers are obtained by the polyaddition of 70 to 100 wt. % of ethylene oxide and 0 to 30 wt. % of propylene oxide to starter compounds2. i-pentane and/or n-pentane as blowing agent,3. water and4. optionally auxiliary agents and additiveswithB) a polyisocyanate with an NCO-content of 20 to 48 wt. % which has a surface tension of 4.0 to 8 mN/m with respect to i-pentane or n-pentane as blowing agent.