Tool head for the extrusion of tubular or tubular preforms made of thermoplastic material

摘要

An extrusion die (1) for prodn. of tubular or pipe section, esp. for subsequent mfr. of blown film comprises (i) inner (4) and outer (5) tool sections forming an annular gap (8) concentric to the die axis; (ii) melt manifold (6) with a spiral channel (10) which enters the annular gap (8) at the lower end; and (iii) feeding unit (7) for the melt attached to the outside of the spiral manifold (6). Pref. the spiral channel is located in the parting line between the die components. The parting line may be horizontal or concial. The manifold may have two separate channels (10) positioned one above the other, one channel being offset relative to the other. Several channels interlaced with each other may be located in one plane. USE/ADVANTAGE - For extrusion of tubular section thermoplastic profile, esp. for blown film mfr. Has simpler construction and improves melt homogenity.