Imagine this: the average semi-truck (72’) can fit 26 standard pallets inside it, without stacking. A single standard pallet can carry up to 4,600 lbs of cargo. That means just under 120,000 lbs of cargo can fit inside a semi-truck.
If it weren’t for industrial stretch wrap, it’s safe to say that much of that cargo would be tossed around, torn up, or shattered by the time the shipping container reached its destination. Stretch wrap plays an incredibly important role in the transportation industry, but what is it?
If you want answers, look no further! We’ve put together this introductory article on all things stretch wrap.
What is Stretch Wrap?
Not to be confused with saran wrap, stretch wrap goes by many names; stretch film, plastic stretch wrap, and industrial stretch wrap are some of the more common ones.
As its name implies, stretch wrap is a highly stretchable plastic film. Its primary function is to unitize loads, though it has several secondary functions that we’ll go over in this article.
Check out this article’s accompanying video to watch one of our packaging directors demonstrate the use and efficacy of several different types of stretch wrap!
What is Stretch Wrap Made Of?
First things first, what is stretch wrap made of?
Industrial stretch wrap is made from linear low-density polyethylene (LLDPE). While other types of polyethylene can be used, LLDPE is the most common material because of its elongation at break and puncture resistance.
Those are some big terms, I know. But what it really means is that a special type of plastic is used in the making of stretch wrap so that the product can have a high elastic recovery, which is ultimately useful for wrapping and holding large loads together.
What is Stretch Wrap Used For?
As mentioned earlier in the article, stretch wrap’s primary function is to secure products together so that the loads don’t fall over in transit. More often than not, this means securing products or materials to a pallet so that they can be shipped without damaging the load, or any other materials being shipped with the load.
All it takes is a basic layer of industrial stretch wrap to a load to a standard pallet. Its low cost and high efficacy have made industrial plastic wrap a staple of the shipping and transit industry. More than just a load stabilizer, though, stretch wrap has several secondary functions.
One of its many benefits is how it helps to reduce product loss. Industrial plastic wrap is very stretchy. Its elasticity allows the plastic stretch wrap to apply pressure to whatever it is securing when it’s wrapped around a load, keeping things in place. Because of this, fewer items fall off pallets and go missing in transit.
It’s for that same reason that industrial stretch wrap improves the stability of packages and the efficiency of handling and storing loads while decreasing the risk of injury for workers.
When looking at different varieties of stretch wrap, there are a host of added benefits, from UV protection, to color-coding. We’ll cover all that later in the article.
How is Stretch Wrap Made & Why Does it Matter?
There are two main processes by which plastic stretch wrap is created, the first is cast extrusion, and the second is blown extrusion.
Let’s break down the difference between these two extrusion processes.
Cast vs Blown Stretch Wrap?
Let’s start with cast stretch wrap. Cast stretch wrap is made by a process called cast extrusion. In this process, plastic material is heated up and continuously melted into a flat die slot so that it can be pushed out onto a cooled roller, causing it to re-solidify in a new shape.
This process boasts a handful of benefits, like clearer transparency, ease of use for stretching, a good grip with two-sided cling, and less noise when stretching. Due to reduced manufacturing costs, cast stretch wrap is also more affordable to produce, making it a popular option over blown stretch wrap.
In a similar process to cast stretch wrap, the blown extrusion process begins by melting plastic material and pushing it through a die slot; imagine funneling hot, melted plastic through a tube and onto a flat, chilled surface so that it cools as a thin sheet.
Where blown extrusion differs from cast extrusion is that the die slot is ring-shaped, and the plastic is pushed through vertically to form a refined tube. Then, air is blown through an opening in the center of the die, causing the tube to expand like a balloon. From the top, cool air is blown onto the tube, chilling the plastic.
This process creates a tougher, yet more flexible stretch wrap. On top of that, blown stretch wrap has a high degree of memory once stretched, leading to more secure loads. Its superior memory, strength, and tear resistance make it an effective option over cast stretch wrap. Blown stretch wrap however is more expensive than cast stretch wrap.
Whether you should be using blown or cast stretch wrap should be determined by weighing out the benefits of each to see which is more applicable to your operation.
Blown extrusion produces a higher cling quality, but the cost of production is also higher because it produces more film per hour than cast extrusion. The blown extrusion process is also less consistent, leading to a less consistent product.
Cast extrusion is a faster process that produces a more consistent product that has better performance characteristics. While the cling quality is not as good as blown stretch wrap, this is offset by a quicker and more cost-effective production.
At the end of the day though, both of these products are viable for securing loads to pallets.
What Are the Different Types of Stretch Wrap?
Industrial stretch wrap comes in many varieties, each with its own use. When stretch wrap has a specific use, other than to unitize loads, it’s referred to as specialty stretch wrap. Here, we’ll review some of the most common specialty stretch wraps.
Pre-Stretch Wrap
Advantages: Pre-stretch wrap is just stretch wrap, but stretched up to 90% of its maximum stretch rate. This means it requires less stretching during the application process, which translates to about 50% less film consumption than other industrial stretch wraps.
Disadvantages: Because it is already stretched out, this film is thinner than your standard stretch wrap, meaning it has poor puncture resistance. In large or uneven loads where there are multiple corners, that can mean multiple punctures.
Use Case: If you’re looking to increase cost-effectiveness without sacrificing quality, pre-stretch wrap is your go to. Because it uses about 50% less film, it can lead to huge cost savings.
UV Stretch Wrap
Advantages: Ultraviolet (UV) stretch wrap helps to protect the integrity of the stretch wrap from harmful UV rays by preventing photodegradation, a process by which rays of sunlight and the air can cause particles to degrade, damaging the stretch wrap.
Disadvantages: UV stretch wrap has two distinct disadvantages. The first is that it is more expensive than standard stretch wrap, owing to the film’s special chemical makeup. The second is that it is made to order, which usually takes about a month to get to your business.
Use Case: If you’re wrapping or storing loads outdoors, especially for extended periods of time, and want to avoid the stretch wrap degrading, then UV stretch wrap is the way to go.
Vented Stretch Wrap
Advantages: Vented stretch wrap allows products being contained by the wrap to get fresh air flow. This is particularly effective at creating the proper ventilation for produce to breathe so that it can ripen during transportation, though it is also used for meat, frozen foods, and plants.
Disadvantages: This stretch wrap has holes all over it, making it far easier to see what is being carried than other types of stretch wrap. It also has less strength than standard stretch wrap. This is because there is less plastic in it as a result of being covered in holes.
Use Case: If you ship produce that needs to breathe, especially for the purpose of ripening, this variety of stretch wrap is the best option.
Anti-Static Stretch Wrap
Advantages: A special additive that is applied to anti-static stretch wrap eliminates the possibility for this film to experience an electrostatic discharge. It clings tightly to itself for added security and reduces the amount of generated static compared to normal stretch wrap.
Disadvantages: Anti-static stretch wrap is typically thicker than your standard stretch wrap. This can be a problem if you need to see through the stretch wrap, as the added thickness can cause increased opaqueness. There is also the problem of limited manufacturing because it is more expensive.
Use Case: Anti-static stretch wrap is great for shipping electronics, electrical equipment, or anything flammable when you don’t want to risk the chance of a static shock.
Colored Stretch Wrap
Advantages: The use of colored stretch wrap is for any facility that needs to easily separate shipments. The USDA, for example, only uses blue stretch wrap so that it is easy to identify if it gets in any food. It can be used as a means of color-coding, both during shipping and in storage. It is also designed to be puncture resistant.
Disadvantages: Colored stretch wrap can make it more difficult to see exactly what products or materials are secured to the pallet. This can make it a problem if transportation workers need to know what is in the load they’re transporting. It is also made to order, meaning that if the manufacturer doesn’t already have a batch in stock, it can take a long time to be produced and delivered to your business.
Use Case: Colored stretch wrap is useful for everything from warehouse color coding to inventory dating. Create a system of organization, implement it, and watch as the efficiency of your shipping and storage increases.
Coreless Stretch Wrap
Advantages: Coreless stretch wrap is more sustainable than regular stretch wrap because it does without the core, leaving nothing to be thrown out after all the stretch wrap is used up. Pair with a reusable core for more efficiency. In addition, it will always come pre-stretched.
Disadvantages: Coreless stretch wrap is the exact same as pre-stretch wrap, just without the core. Other than having no core, it has no advantages or disadvantages over pre-stretch wrap.
Use Case: If you’re looking for a fully green manufacturing plan, or wish to promote sustainability at your business, coreless stretch wrap is the way to go.
Biodegradable Stretch Wrap
Advantages: Biodegradable stretch wrap is one of the newest stretch wrap variants out there. It is not only fully recyclable, but it is also biodegradable. So, while you may recycle it, the film will fully degrade in a landfill in approximately two years. It can break down in water or on land and breaks down so fully that it can be consumed by living organisms.
Disadvantages: This stretch wrap is soft, meaning that it has low tear resistance compared to standard stretch wrap. This affects its ability to maintain the security of an especially heavy load in transit.
Final Thoughts
Stretch wrap is an integral tool in load unitization, transportation, and storage. While it is essential to the structural safety of loads, it also provides an array of bonus benefits when taking full advantage of the wide selection of specialty plastic stretch wraps. Whatever the type of transportation or storage, there is a variety of stretch wrap that can help you in more ways than one.
Whether you’re located in the United States, Puerto Rico, the Caribbean, or Canada, Imperial Dade locations can provide your business with the tools and guidance you need to find the right stretch wrap for your operation. We also offer a wide variety of commercial manufacturing equipment including hand stretch wrap tools, stretch wrap machines, different specialty stretch wraps, and more. Reach out to us for more information today.