Layer Multiplication (Multiplier) Technology

A potentially revolutionary flat-die system produces films and coatings with an order-of-magnitude greater number of layers than conventional coextrusions, yielding microlayer structures that improve moisture and gas barrier, encapsulate gels and “un-melts,” and enable manufacturers to make more economical use of high-cost materials. The technology is based on a patented “layer multiplier” system developed by The Dow Chemical Company and licensed from Dow by EDI. In a typical configuration, three or more extruders feed melt streams into an EDI-streamlined feedblock, which produces a uniform multi-layer “sandwich”; this in turn is fed into a layer-multiplier device built by EDI using Dow’s patented design. In this device the layers are multiplied in stages—for example, three layers are multiplied into twelve, which are multiplied into forty-eight. The finished micro-layer structure is then distributed in an EDI coextrusion manifold to the target product width.

As coextruded structures proliferate well beyond the standard limits of five, seven, or nine layers, here are some of the benefits: Enhanced barrier properties, economizing on costly materials, fewer web breaks and new combinations of properties.