Coextrusion

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Coextrusion The process of extruding two or more materials through a single die with two or more orifices arranged so that the extrudates merge and weld together into a laminar structure before chilling.

Advantages

“Coextrusion is another tool in the well-outfitted converter's tool chest,” according to Bruce Foster, technical sales manager of Mica Corp. “It provides better quality monolayer extrusion coatings over a wider variety of widths and line speeds; the potential to save on the amount of premium resins by filling with lower cost materials; and the possibility to make multi-layer, multi-functional structures in a single pass.”

A group at Battenfeld Gloucester Engineering Co. feel that coextrusion offers targeted performance using specific polymers in specific layers, a reduction in the number of process steps, and lower cost, says spokesperson Bill Hellmuth, senior product manager — blown film systems.

Hellmuth states lower cost is possible because of the reduced amount of expensive polymer for equal performance, the use of inexpensive polymers without sacrificing performance, a reduction in setup and trim scrap, and the potential for use of a recycle layer.