Die, system, and method for coextruding a plurality of fluid layers

Abstract

A die for coextruding a plurality of fluid layers generally includes a primary forming stem, one or more distribution plates, and a microlayer assembly. The microlayer assembly includes a microlayer forming stem and a plurality of microlayer distribution plates.

Description

BACKGROUND OF THE INVENTION[0001]The present invention relates to a coextrusion die and, more particularly, to a coextrusion die containing both a microlayer assembly and one or more distribution plates to produce coextruded films having both microlayers and thicker, conventional film layers.[0002]Coextrusion is a technique for producing a multilayer plastic (polymeric) film by bringing two or more molten polymers together in a die, in which the polymers are formed into a generally tubular or planar shape, juxtaposed in layered form, and then pushed out of an annular- or slot-shaped opening in the die. Once outside of the die, the still-molten multilayer film is exposed to an environment having a temperature that is maintained below the melting point of the component polymeric layers of the film, which causes the layers to melt-bond together as they cool and solidify.[0003]Multilayer films typically have a thickness in the range of 50-200 mils upon emergence from the die, but the fi...

AI Technical Summary

Benefits of technology

[0015]Another aspect of the invention is directed to a system for coextruding a plurality of fluid layers, comprising a die

Problems solved by technology

Unfortunately, it has proven to be difficult to combine the flow of thin layers, such as microlayers, with relatively thick layers in such a way that the physical integrity and independent properties of the thin layers are maintained.

The resultant loss of the integrity and independent characteristics of the microlayers diminishes or even eradicates the beneficial properties thereof.

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