Plastic film recycling performance depends more on film structure and contamination level than machine size alone. Single-layer and multilayer films behave differently during melting, degassing, and filtration. Selecting the correct extrusion configuration is critical to avoid gel formation, pressure instability, and poor pellet quality.

Table – Film Type vs Recommended Recycling Configuration

Single Layer Film – Process Explanation
Single-layer films such as LDPE and LLDPE are comparatively stable during extrusion when clean and dry. Processing complexity increases with moisture, printing ink, and surface contamination. Non-vented systems are suitable only for controlled industrial waste, while vented extrusion becomes mandatory once moisture or volatiles are present.

Multilayer Film – Process Explanation
Multilayer films introduce incompatibility between layers, differential melting behavior, and higher volatile generation during processing. Barrier layers such as EVOH or PA significantly increase degassing requirements. Two-stage and three-stage extrusion systems are used to progressively stabilize the melt, control pressure, and prevent surface defects in pellets.

Why Multilayer Film Needs More Than One Stage
In multilayer film recycling, gases are released at different temperature zones due to varied polymer chemistry. Single-stage extrusion fails to remove these gases consistently, leading to die surge, voids, and gel formation. Multi-stage extrusion separates melting, degassing, and homogenization functions across stages, improving process control and output reliability.