| 摘要 |
<p>Method and apparatus for making plastics foam such as polyurethane foam in the form of a pre-froth for filling moulds, using a fluorocarbon as a gas-producing agent. To avoid gas break-out and facilitate control of density and quality according to the invention the pressurised composition undergoes several pressure drops. <??>In one preferred form the pressure drops are produced at automatically controlled valves. In another embodiment the pressure drops take place at orifice plates. </p> |
