Separate plastic composites - With an application-specific intermediate layer

Plastic composite recycling is greatly valued in today’s world. It is becoming increasingly important to recycle not only packaging, but also technical components. The current trend is to manufacture components from multi-material composites, but this is contrary to the single-material requirement for recycling. Many components, such as vehicle dashboards, are manufactured by spraying a thin thermoplastic elastomer layer over a thermoplastic substrate. The combination of materials is selected to optimize bonding. It is then impossible to separate the layers out again for recycling. The only remaining recycling solution is often either thermal recovery (incineration) or non-pure recycling for use in applications with lower material requirements. Or such components can be disposed of or separated by means of solvents, but the latter solution is expensive and environmentally harmful. So Kunststofftechnik Paderborn (KTP) at Paderborn University has developed a method for separating such composites. It uses an intermediate layer injected or co-extruded between the plastic components. This layer is selected to provide sufficient bonding in the operating temperature range, and a defined stimulation (thermal conduction or induction) can cause only it to melt. This allows plastics to be separated for single-material recycling.