4. Coextrusion

Coextrusion involves the simultaneous hot extrusion of two or more plastic sheets into flat dies, and their immediate assembly while still hot, so that they bond together.

There are several techniques and machines: multi-channel dies, single-channel dies with coextrusion distributor, tubular coextrusion.

If the different polymers are not compatible with each other, they must be coextruded with the interposition of a "coextrusion binder", which is a kind of adhesive material (adhering to the different polymers).

Thanks to their excellent adhesion to a wide range of polymers, and their excellent weldability, ethylene-acrylic ester copolymers (Lotader and Orevac from Atofina) can be used either as bonding agents in 3-layer, 5-layer or higher laminates, or as weld coats in 2-layer laminates.

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