| 摘要 |
In the production of foamed thermoplastic synthetic material, synthetic material is melted in a screw extruder and fluid propellant is injected into the molten sythetic material. The residence time of the molten mixture has a determining effect in regard to uniform distribution of the propellant and thus also in regard to the uniformity of the cell structure. In order to provide for homogeneous mixing of the propellant and uniform cooling of the molten mixture, without using an excessively long screw extruder, the screw extruder is provided, downstream of a melting region thereof and of an injection opening thereof through which propellant is introduced, with flow obstruction structure which is by-passed by static mixing structure disposed outside the screw extruder. The molten synthetic material is simultaneously mixed with the propellant and cooled in the static mixing structure. |
