Composite thermoplast sheet - extruded from one fishtail die from already combined flows of different materials

摘要

In making multilayer thermoplastics sheet or strip for subsequent thermo-moulding by bringing together two or more threads (flows) of different plastics before they enter the fishtail extrusion die, then extruding them together, as in the parent patent, the cross-sections of the flows are shaped as they are brought together, so as to suit the flow pattern in the fishtail die. This enables greater control of individual layer thickness to be achieved. Pref. for thick sheet parabolic flows are combined.