Managing Recycled Plastic Compliance under European Waste Rules
Managing recycled plastic compliance under EU waste rules requires challenge-tested decontamination, accredited migration testing, and audited traceability dossiers.
Multi-Layer Co-Extrusion
Meaning
Polymer processing technique where several layers of resin are combined in a single die to create a composite structure with specific barrier properties. It governs the distribution of material properties across the thickness of the part and stops applying when the melt streams have solidified into a single sheet.
Layer Adhesion
Compatibility between the different plastic types ensures the structure does not delaminate under stress. Multi-layer co-extrusion often uses thin tie layers of modified polyolefins to bond materials with different polarities. If the bond is weak, the barrier properties of the final package will fail.
Proper selection of tie resins prevents air pockets from forming between the functional layers.
Property Tailoring
Designers combine the moisture resistance of polyethylene with the oxygen barrier of ethylene vinyl alcohol to maximize shelf life. Each layer performs a task, such as providing stiffness, colour, heat sealability and puncture resistance. This approach allows for thinner packaging that uses less total resin.
The precision of the feedblock determines the uniformity of these layers.
Cost Reduction
Placement of recycled or low cost filler material in the center of the structure lowers the overall price of the part. Virgin resin is only used for the outer skins that touch the food or the consumer. Such a configuration maintains the high quality appearance of the product while utilizing cheaper feedstock.