The Benefits of Coextrusion

by Michaela Cultrara

Coextrusion is the process of simultaneously producing a foam sheet while adding a film layer to top, bottom or both top and bottom of the sheet through a multi-layered extrusion die to create a single sheet in a single operation. This provides a base layer of foam with cap layers of material having different properties from the foam. These properties may be designed for protection, printability or aesthetics.

To achieve this in a traditional process the foam sheet is first produced by a foam extruder. A secondary operation either coats or laminates the foam sheet on separate equipment to provide the desired cap layer. Coextruded foam sheet can be produced using polystyrene, polyethylene and polypropylene which can be used in food packaging, medical, automotive and building industries. The sheet properties can be adjusted by varying the raw materials and operating conditions. Below is a list identifying the distinct benefits of this process.

CoExtrusion  line while testing

1) Cost

  • Coextrusion removes the need for a laminator. The coating extruder supplies material straight onto the foam in the die thus removing operations later on in the process
  • Requires less operators with the simplified line configuration.
  • Scrap related to sheet cutover during lamination and coating is eliminated.

2)  Productivity

  • Less equipment to maintain or break down.
  • Reduce process time because off gassing time required before coating or laminating is eliminated.
  • Reduction of setup time with laminator removed from system.

3) Quality

  • Only have to manage one process rather than multiple processes and materials.

4) Sustainability

  • Less energy required to run simplified process versus multiple additional downstream machines
  • Condensed equipment layout requiring less floor space.

5) Applications

  • Rigid cap layer on foam plates/trays.
  • Cap layer required for a barrier.
  • Formed products that require cap layer for protection or rigidity.
  • Smooth surface for quality printing.

Coextrusion is an ideal process for cost effective products that have different characteristics throughout the thickness of the finished sheet. The ability to customize the finished product while reducing manpower and startup cost is what makes the Coextrusion process so appealing to manufacturers. Contact us to understand how we can provide a Coextrusion solution to your existing product. Or allow us to help you develop a new product.