METHOD AND APPARATUS FOR EXTRUDING FOAMED ARTICLES

摘要

During extrusion of foamed articles made from thermoplastic, a molten mass comprising heated, pressurized plastic which has been mixed with a foaming agent is pressed firstly through an orifice (4) which shapes the article and then through the nucleator (6). Then, the article is cooled. This results in a very fine microfoam structure. Particularly good results are obtained if the molten material is compressed for a short time immediately after it leaves the nucleator, during which compression it is ensured that no shear forces, or only slight shear forces, are generated in the molten mass.