apparatus for the preparation of films and more layers and mold or more layers circular matrices

摘要

A multi-core circular die for preparing multi-layer tubular film from thermoplastic resins which includes a plurality of cores having concentric tube portions and central spherical portions which are rotatably fitted with each other along the spherical portions. A plurality of tubular passages are provided for conducting the flow of the molten resins, the passages being formed within spaces formed between the tube portions of the cores, a housing surroundingly securing the cores together. Adjusting bolts are provided within the lower portions of the cores and housing so as to adjust the angles of the cores relative to the axis whereby the thickness of the passages, and consequently the film layers, may be altered so as to achieve film layers of uniform thickness.