| 摘要 |
PCT No. PCT/NO90/00118 Sec. 371 Date Jan. 17, 1992 Sec. 102(e) Date Jan. 17, 1992 PCT Filed Jul. 16, 1990 PCT Pub. No. WO91/01212 PCT Pub. Date Feb. 7, 1991.A process for the continuous or semi-continuous production of cellular plastic from a plastic mass containing a blowing agent and, optionally, other process-regulative substances and additives. The process starts by raw materials to a plastic processing machine and kneading the raw materials in the plastic processing machine under conditions of temperature and pressure which will produce an expanding mass only upon release of pressure. The expanding mass is transferred directly to a cooling zone to produce a continuous mass having high viscosity and rigidity and an approximately flat velocity profile under pressure formed by an upstream-directed pressure component. At varying intervals the plastic mass is transferred to a braking-retaining zone which may be an integral part of the cooling zone for build-up of the upstream-directed pressure component until the pressure in the plastic mass in the zones located upstream is sufficient to prevent expansion of the plastic mass. The final step in the process is controlled to expand the mass to the desired density after transfer to a heating/expansion/forming zone. |
