4. Production of material granules

Thermoplastic granules for injection or blow moulding and extrusion of pipes and profiles are produced in industrial plants which may include :

• reactors in which the resins are obtained, then discharged in the form of strips or rods through nozzles located at their lower ends. After cooling, the strips or rods are granulated in granulators;

• extruders fed with strips of material, or resins, additives and fillers in pellet or powder form, which, after plasticization, produce polymer alloys or resins mixed with additives and fillers. The rods obtained at the die exit are cooled and then granulated by a granulator which can be installed at the head of the extruder;

• internal mixers where resins, additives and fillers are introduced. At the end of the mixing and plasticizing operation,...