RO117007B1 - Extrusion head for coextruding plastic materials - Google Patents

Abstract

The invention relates to an extrusion head for simultaneous extrusion of a number of 3 to 6 materials as concentric layers in a plasticized tube. The extruded materials are polymers which may have different physical-mechanical properties and molecular structures. The plasticized tube is employed in the blow-moulding manufacturing of containers made of virgin plastics or of combinations thereof with recycled plastics. According to the invention, the extrusion head is designed as an unitary assembly and is mounted on the frame of the blowing-coextruding unit so equipped by means of an attachment plate (1) located at the upper end of the head, the other components thereof being placed under said plate. An upper feeding plate (2), in contact with the attachment plate (1), is located and guided on a intermediate distributing core (4) inside of which an interior distributing core (3) is mounted. The pot (5) which envelops both distributors makes therewith the upper level of the head. The lower level of the coextrusion head is secured to the upper level and comprises an intermediate feeding plate (6) which supplies the material to a distributing core (7) located inside a pot (8). The two levels of the coextrusion head are assembled by means of some tie bars (10). As a result of the coextrusion process, the said tube is made at the desired size, due to a nozzle and a mandrel (11) located at the lower part of the coextrusion head. The technological components of the coextrusion head are heated by means of some flatened resistors (12), at controlled temperatures which are maintained within a preset range of values by means of some thermocouples (13).