| abstract |
Process for the production of granules of expandable thermoplastic polymers by means of extrusion, which comprises: i) melting the polymer in a single- or multi-screw extruder (2); ii) incorporating an expanding agent in the polymer in the molten state; iii) granulating the polymer thus obtained in a device comprising a die (111), containing a series of ducts (115) made of a material having a high thermal conductivity (114), a cutting chamber (118) containing a set of hydraulic nozzles and a cutting system equipped with a set of knives (215) with a cutting edge which is radial with respect to the surface of the die; iv) annealing the granules thus obtained; v) cooling the annealed granules to room temperature. |