Extrusion heads for the CoEx application usually run in layer configurations from 3 to 6 layers. In some cases 7 layer applications are needed and have been built successfully as well.
CoEx is used when a combination of materials is required that do not bind together and a special adhesive layer is needed. The parison then consists of from 3 to 7 layers. Such configurations are, for example, necessary for barrier characteristics or for high gloss outside layers.

The following is an example of possible layer structures:

CoEx 3 layers:

• Inner layer HDPE: 90%
• Middle Adhesive: 5%
• Outer layer Nylon: 5%
  

Application would be:

• High- end Cosmetic containers for a scratch free surface.

If the layer structure is reversed, the inner layer is used as a barrier layer. This structure may be used to hold hair coloring lotions, for example.

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CoEx 4 layers:

• Inner layer Barrier: 10 %
• Adhesive: 5 %
• HDPE + Regrind: 75 %
• Outer Layer HDPE + Color: 15 %
  

Applications would be:

• Agro-chemical containers for superior barrier properties
• Food and Beverage Containers

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CoEx 6 layers:

Inner Layer Virgin PP: 20%

• Adhesive: 5%
• Barrier: 5%
• Adhesive: 5%
• PP &Regrind: 50%
• Outer Layer Virgin PP: 15%
  

Applications would be:

• Food and Beverage Containers

The abovementioned examples cite only approximate numbers. A wide range of layer configurations is possible that will fit your specific needs.
All heads are view-stripe capable.

Our package system includes:

• Extrusion head for CoEx processing
• Vertically mounted satellite extruders for the processing of the additional raw materials and/or for the extrusion of view stripes
• Separate control cabinet for extruder drive control as well as additional heat zones for head and extruders.