| 摘要 |
A PVC plastisol is treated with CO2 air or CO2N2 mixtures which are recycled by pumping at - 10 to 28 deg.C, particularly 0-20 deg.C, and at pressures above the vapour tension curve of CO2 but below the pressures at which there are homogeneous gaseous mixtures of CO2 air or CO2N2. When putting into operation an installation for the production of new or cleaned foam, operation is started by working above the pressures where there exist homogeneous mixtures of CO2 air or CO2N2, and the pressure is subsequently lowered below the pressures where such mixtures exist, but above the vapour tension curve of CO2. The process can be carried out continuously at lower pressures, and this represents a saving in energy. |
