device for the discontinuous production of multi-layered, coextrudierter schlauchartiger preforms from thermoplastic plastic, the tuyere

摘要

A method for manufacturing large-volume hollow bodies of plastics material with multiple-layer walls. The apparatus defines an accumulation chamber and has a nozzle outlet. A plurality of material layers are joined into a multiple-layer plastic material melt within a tubular plunger which is movable in axial direction of the apparatus. The multiple-layer plastics material melt is conducted in a flow duct which widens in the shape of a funnel toward the accumulation chamber. The tubular plunger is forced by the melt to move in axial direction away from the nozzle outlet. The material melt is ejected as a multiple-layer extruded material by moving the tubular plunger in axial direction toward the nozzle outlet.