Process for the production of polyurethane foams

摘要

Polyurethane foams are continuously produced using CO2 as the blowing agent and a filler. The filler is mixed with at least a portion of one of the reactive components and any agglomerates are virtually completely broken up during or subsequent to such mixing. The filler-containing mixture is passed through at least one filter element to filter out any oversize grains, residual agglomerates and/or impurities. The CO2 is added under pressure to at least a portion of at least one of the reactive components to generate a mixture which comprises liquid CO2 or a mixture which comprises liquid CO2 and filler. This mixture is mixed with the other reactive component(s) and optionally further additives. The reactive mixture which includes CO2 and filler is then decompressed by division into a plurality of individual streams at shear velocities above 500 s-1 and the flow velocities thus generated are reduced before discharge. The reactive mixture is then applied to a substrate and allowed to cure to form a polyurethane foam.