| 摘要 |
<p>In a process for producing particles of fluid packing material in the form of spherical segments 18, made from plastic, which have a convex outer surface and another concave inner surface, the plastic material is mixed with additives, for example bubble-forming agents, dye pigments and similar agents. The plastic material is fed by means of a feed hopper 27 to an extruder via a hole in a sleeve 13 which surrounds the extrusion screw. The plastic material is plasticized on passing through the extruder 14 and, owing to the difference in speed which exists in the transverse section of the mass, it emerges from a hole 15 of the die with a curved surface. The plastic material is cut directly in the hole 15 of the die and before considerable expansion takes place. Before processing the plastic granules in the extruder 14, a bubble-forming agent (nucleation agent) is applied to its surface in a drum 5. (Figure 1).</p> |
