How is the stretch film made?

Stretch film, which is a strong plastic film, is usually made by Linear low-density polyethylene (LLDPE) with strong elongability and penetration resistance.

Applicable places:

1. It is mostly used for wrapping pallets and goods on pallets, which will make them fixed on the pallets and reduce the collision during transportation;

2. Used for storage in the warehouse, wrapping the stretch film on the goods can make them moisture-proof and dust-proof, and reduce the aging and other losses caused when the goods are stacked in the warehouse

Production process:

Blown stretch film

Blow film extrudes a thick film from a circular mold and blows a large bubble of air into it.The volume of the bubbles and the original diameter and thickness of the extrusion tube determine the final specification of the material (thickness).

The vertical bubble can be several feet tall, and the film cools as it is pulled up by rollers, which collapse the bubbles and control the thin, flat film tube as it winds.

Usually in the rewinding process, the edges are cut off, the coil is cut to its width and wound in a straight line as the film is extruded.

Cast stretch film

Casting film production involves different processes.In this case, the resin is extruded through a linear mold and exuded onto a large diameter cooling roll.(Note that they may not actually be cold, but much colder than semi-molten plastic.)Depending on the original thickness of the extrusion, the resulting film is sometimes thinned to the target specification by winding the resulting film faster than the extrusion speed.

This is a horizontal process, as shown in the schematic diagram.

According to general industry estimates, the spread film accounts for another 70-80% of the stretch film manufacturing.

Differences between stretch film that is cast vs. blown

For all the commonalities, there are some differences. Every formulation and manufacturers is a bit different, but some general rules of thumb apply.

Blown stretch film tends to:

• be very resistant to puncture
• have higher levels of [cling" (how the film `sticks` to itself)
• make more noise unwinding

Cast stretch films often:

• are clearer & shinier on a load
• unwind quieter
• resist tear propagation