Process for foam production using dissolved under pressure carbon dioxide

摘要

PCT No. PCT/EP97/02688 Sec. 371 Date Dec. 3, 1998 Sec. 102(e) Date Dec. 3, 1998 PCT Filed May 26, 1997 PCT Pub. No. WO97/47453 PCT Pub. Date Dec. 18, 1997A process is described for the continuous production of polyurethane block foam using carbon dioxide which is physically dissolved under pressure as a foaming agent, wherein before the polyol and isocyanate components are mixed the carbon dioxide is dissolved in the polyol component and air or nitrogen is dissolved in the isocyanate component, both components are fed to a mixing chamber in which a pressure prevails which is 70 to 150% of the solution pressure of the CO2 in the polyol component, the isocyanate component is fed to the mixing chamber at a pressure of at least 30 bar and is injected therein with depressurization down to the mixing chamber pressure, wherein air or nitrogen in an amount of at least 1 g per kg CO2 is dissolved in the isocyanate component, and after emerging from the mixing chamber the mixture is depressurization to atmospheric pressure.