| 摘要 |
In a method for producing cellular plastic with closed cells, and containing polyvinylchloride, a chemical blowing agent, a stabilizer, and possibly other process controlling substances and additives, the plastic mixture is treated mechanically in a plastic treating machine, and is fed to this phase of treatment at a well gelatinized state with a chemical blowing agent which was finely distributed in the plastic mixture in connection with gelatinization, but is not decomposed/vaporized, or only decomposed/vaporized to a negligible extend. The plastic mixture is treated mechanically in the plastic treating machine at a temperature above the decomposition/vaporizing temperature of the blowing agent so that the latter is decomposed/vaporized while treatment occurs, at a pressure above the internal pressure of expansion in the decomposed/vaporized blowing agent, the plastic mixture after decomposition/vaporizing of the blowing agent being made to expand to the desired shape by reduction of the external pressure. |
