Machine Grade Stretch Film

Material and Construction

Machine grade stretch film is manufactured from linear low-density polyethylene (LLDPE) resin, processed through either cast extrusion or blown extrusion methods. Cast films are produced by extruding molten resin through a slot die onto chilled rollers, resulting in high optical clarity, quiet unwind characteristics, and consistent two-sided cling. Blown films are formed by extruding resin through a circular die and inflating it into a bubble, producing a film with superior puncture and tear resistance, higher elastic memory, and one-sided cling.

Gauge Selection and Performance

Film selection depends on the specific application, including load weight, profile, handling conditions, and containment requirements. A wide range of film options is available to accommodate everything from light, uniform loads to heavy, irregular, or high-risk shipments. By evaluating each operation individually, the appropriate film type, gauge, and performance characteristics can be selected to ensure load stability, reduce waste, and maintain efficiency across a variety of packaging environments.

High-performance thin-gauge films in the 30-47 gauge range utilize metallocene LLDPE resins and multi-layer co-extrusion technology (up to 11 layers). These films achieve load containment equivalent to conventional films at roughly double the gauge. A 47 gauge high-performance film, for example, can match the holding force of a conventional 80 gauge film while using significantly less material per pallet. This gauge equivalency is achieved through nano-layer architecture, where each micro-layer contributes specific properties: core layers provide elastic recovery, metallocene layers add puncture resistance, and skin layers control cling and abrasion characteristics.

Cast vs. Blown Film Selection

• Cast film is the standard choice for uniform, boxed loads on high-speed wrapping lines. High clarity allows barcode scanning through the wrap. Quiet unwind operation suits noise-sensitive facilities. Two-sided cling provides consistent layer-to-layer adhesion.
• Blown film is preferred for heavy, irregular, or sharp-edged loads where puncture resistance is critical. Superior tear propagation resistance prevents film failures around protruding corners. One-sided cling prevents adjacent pallets from bonding in storage. Higher elastic memory maintains load force over time.

Pre-Stretch and Film Yield

Machine stretch film is designed to be elongated during application, with stretch ratios ranging from 150% to 300% depending on film type and wrapper configuration. Higher stretch ratios reduce material consumption per pallet. Pre-stretch carriage systems on wrapping equipment mechanically elongate the film before it contacts the load, providing controlled and consistent wrap tension across the full pallet height.

Load Retention and Film Memory

After application, film contracts slightly to maintain constant inward pressure on the load. This load retention property prevents load shifting during transit and storage. Blown films generally exhibit higher elastic memory than cast films, making them better suited for loads that may shift or settle after wrapping.