5 Stretch Film Factors to Consider When Unitizing Loads


The best ways to use and save with stretch film.

If shipping materials is a large part of what you do, you’re probably already familiar with the function of stretch film — but have you ever stopped to consider whether the film you’re using is right for the job, or if there’s a better, maybe even more budget-friendly version to meet your needs?

There are many considerations to keep in mind when selecting stretch film. Each one can impact how safe your materials stay during transport, in what condition they arrive at their final destination, and how much money comes out of your budget to cover film costs… or the cost of damaged goods that weren’t properly contained. Herein we give you a list of these considerations, so you can properly unitize loads at your facility for shipping.

Stretch Factor #1: When used properly, stretch film improves efficiency during shipping.

When the items you’re preparing to ship are properly wrapped, they are far less likely to shift, slip or fall out. This means your products arrive in one piece, and your loss is minimized. It also makes for a smoother, easier ride, which may save a number of resources:

  • Time: If a driver has to stop to adjust a load that’s shifted, or if a heavy load shifts to the point that it causes damage to the vehicle, you can expect delays in getting your materials where they need to go.
  • Fuel: More time on the road, more starting and stopping, and shifting weight load means more fuel stops, which adds to your costs.
  • Money: When items are sufficiently secured, transportation and unloading is smoother and quicker, which means you may save in driver and labor costs.

However, proper wrapping isn’t the only consideration to make when determining the safety of your goods.

Stretch Factor #2: Remember to consider the route, geography and weather your goods may encounter during transport.

When you’re transporting goods, you want the best drivers, but the quality of the driving may matter even more than you think. Stopping and starting, lightning fast acceleration or slamming the brakes can all result in your stretch film being compromised. This has less to do with the strength of the material, though it does mean you should always wrap your goods properly to ensure the least amount of shifting due to driving conditions.

Another factor to keep in mind is geography. If you’re shipping over distances that include rough terrain, hilly or mountainous areas, you may want to look into a film that is stronger and resists shifting.

Weather can play a role in how your materials arrive as well. Icy, snowy, wet or other poor road conditions may lead to unstable driving, which means loads can easily shift. Make sure to take the forecast into account when preparing to ship large loads.

Stretch Factor #3: Calculate containment force, compression and film stiffness to optimize the application of stretch film.

Previously, the strength and capacity of stretch film was determined mainly by trial and error — obviously, not the most efficient way to do things. However, a recent study has shown that the containment force of stretch film can be calculated, and it can help you select the best product for your needs.

Containment force is a measurement that determines how far a test object can be pulled away from a load, when it is sandwiched between the load and an application of stretch film. Containment force of stretch film is determined by two components:

  • Compression: This is the inward force applied to a load from the stretch film. Basically, it’s how much the film squeezes the load.
  • Film Stiffness: More than just thickness or strength, film stiffness is measured in terms of the force used to stretch the film further than its current length or level of elongation.

If you understand how these components rate, you’ll be able to determine how strong and how tight your stretch film needs to be to keep your load protected.

Stretch Factor #4: Choose the right type of stretch film, blown or cast, for your application.

Stretch films generally come in two types — blown or cast — and your selection can have a big impact on cost and quality.

  • Blown: Blown film is created when resin is heated and a bubble is blown into the liquid. The material is then cooled and rolled. Blown film is typically higher quality, stronger and more puncture resistant — but it’s also more expensive. If your load is lighter and doesn’t contain sharp or jagged edges, this may be too costly an option. Blown film also has more opacity, so if it’s important that you see the items in your load after they’re wrapped, this may not work for you.
  • Cast: Cast film is made when resin is heated and then run over cooled steel rollers. Once the resin firms into sheets, it’s placed on rolls. Cast resin isn’t as strong or as resistant to tearing as blown, but it’s still tough enough to do a number of jobs. It’s also more economical, easier and quieter to use. Plus, the two-sided cling of cast wrap means it’s also more secure.

Stretch Factor #5: Determine the best way to stack your products that will reduce load failure.

There are two basic ways to stack the products you need to wrap, and it could make a big difference in the security of your items, and the film you use.

  • Layer: This involves stacking items one on top of the other in rows. Tests have shown a significant amount of shifting in this formation, even with just one less layer of stretch film than the industry recommendation.
  • Column: This configuration stacks objects vertically into columns. Studies show little shifting, although it does happen when items are not properly wrapped. However, it’s also been shown that while column formation requires several layers of film at the bottom, fewer layers can be used as you get closer to the top of the column, potentially saving time and money.

Find the Right Stretch Film for Your Facility

Wrapping your to-be-shipped materials may seem like a step that doesn’t require much thought, but evaluating your current stretch film against these standards could end up shaving valuable time off your process, and valuable dollars off your bills. If you’d like to speak to one of our experts about your stretch film needs, be sure to contact us, and check out our selection of stretch film products to find the one that’s right for you.


Venechuk, Luke. 2015. “Dissecting Containment Force: Load Compression, Film Stiffness, and their Roles Stabilizing Unitized Goods”.

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