Fig. 4

Production of incorporated ITNs. A simplified drawing of a round yarn polyethylene extruder. (1) the motor driving the extrusion screw. (2) the hopper containing mix of HDPE, LDPE and additives in Masterbatches, (3) the extruder tube with heating and eventually cooling bodies around a central tube with the extruder screw. (4) the die head where 150–300 yarns are extruded in parallel into a water bath (5). (6) a comb that arrange the yarns parallel drawn by the first set of rotating rollers (7). (8) a stretch zone where yarns are drawn by the difference in speed of rotation rollers (9) and (7). (10) a set of combs that guides the yarns to winding up on cones (11). Typically, there are 5–7 rotating rollers on each side of the bath and just as many cones as yarns produced at the die head. The hopper can be fed automatically from containers via a vacuum system or it can be premixed and hand-carried or pumped to the hopper. Extruder screws can have many designs to provide better mixing, but net producers mostly use very simple, single screws