Pre-Stretched and High-Performance Stretch Films

What it is

Pre-stretched film is stretched at the factory before it is wound on the roll. It has less stretch left, so the user does not need to pull hard, and it holds the load with a thinner film. It is common as hand film. High-performance or nano-layer film is coextruded from many thin layers of different resins. The layers give more strength, puncture resistance and holding force at lower gauge than a conventional film. Both are sold to cut film use, waste and wrapping effort.

How to read it

Labels often show two numbers: the actual gauge of the film and an equivalent gauge or "performs like" number. The equivalent gauge is the maker's comparison to a conventional film. It is not a standard rating, and different makers test differently. Ask for the actual gauge, roll length, width, core and recommended use. ASTM D4649 is a guide to selecting stretch films and the test methods used to compare them.

Comparing film types

How to evaluate a claim

1. Wrap the same load type with the current film and the new film.
2. Count the wraps and weigh the film used, or weigh the roll before and after.
3. Check load holding after shipping or a drop or tilt test.
4. Check for punctures at corners.
5. Compare cost per load, not cost per roll.

Key points

• A lower gauge film with the same holding force uses less plastic per load.
• Equivalent gauge claims are a starting point for a trial, not a spec.
• Machine operators may need to change carriage tension and pre-stretch settings for high-performance film.
• Gauge conversions to mil and microns are on the film gauge conversion chart.

Common mistakes

• Comparing rolls by price without comparing length and loads per roll.
• Accepting an equivalent gauge claim without a load test.
• Switching to thin film on sharp-cornered loads without corner boards.
• Leaving wrapper settings unchanged after a film change.

Governing standards: ASTM D4649 (guide for selection of stretch, shrink and net wrap films). Film maker data and load testing.

Reference only. Verify against the current governing code or standard, the manufacturer's data and the project documents before use. Apps for Distributors disclaims liability arising from reliance on this reference.