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Shrink wrap is one of many great ways to protect and transport items. It&#;s strong, durable, and tamper-resistant.
This article will explain exactly what it is, what it&#;s made of, the science behind it and its many advantages.
What Exactly is Shrink Wrap?
Shrink wrap, or shrink film, is a material made of polymer plastic film used to wrap and package pallets and products.
It is a unique form of plastic packaging as when heat is applied, the film shrinks, forming a tight protective layer around the packaged item.
Don&#;t Confuse Shrink Wrap with Stretch Wrap
While both shrink wrap and stretch wrap are used to package and secure products and pallets, their methods are quite different.
While shrink wrap tightens around the packaged item when heated, stretch wrap is wrapped tightly around the packaged item manually, often multiple times, with its elasticity providing the tightness.
What is Shrink Wrap Made Of?
There are a number of plastic polymers used to make shrink wrap, offering slightly different properties. The main four are:
- Polyvinyl Chloride (PVC)
- Polyolefin (POF)
- Polyethylene (PE)/Low-Density Polyethylene (LDPE)
- Polypropylene (PP)
Polyvinyl chloride used to be the most commonly used material, as it is lightweight, inexpensive and has a multitude of uses. However, due to a number of reasons, some countries have banned its use, and in countries where it isn&#;t banned, some major companies have opted to ban it. One of PVC&#;s issues is that it releases a dangerous odour when heated, with it being advised that this is done in a well-ventilated area. Another issue is the concerns around its sustainability, as in most cases PVC is not recyclable.
Because of these problems, polyolefin (POF) has replaced PVC as the favoured plastic polymer used to make shrink wrap in a number of applications. Polyolefin is extremely durable and versatile and is approved as a food-safe material. Furthermore, Polyolefin is made from 100% recyclable materials.
Polyethylene and polypropylene are types of polyolefin, with polyethylene derived from ethylene. When PE is used to make shrink film, it is often in its low-density form - low-density polyethylene (LDPE). This is because LDPE has high strength, durability, and offers the best quality for printing images and text on the wrap.
Check out our dedicated article to learn more about the differences between PVC, Polyolefin and Polyethylene Shrink films.
How To Use Shrink Wrap
To shrink wrap a product, you simply encase and surround it with the plastic film. This can be done manually or by using a shrink wrap machine.
You then need to apply heat to the shrink wrap. This can be done manually using a heat gun, moving the gun around the product until all of the film tightly covers it, or by passing the product through a heat tunnel, which will evenly apply heat around the product, shrinking the film to enclose it.
How Does Shrink Wrap Work?
Now you know the process, how does the &#;shrink&#; in shrink wrap actually work?
The molecule chains of polymers are very long, being made up of many monomers (hence &#;poly&#;). In their natural state, these long chains are randomly intertwined, coiling and twisting around one another with no specific direction or alignment. When these polymers are used to manufacture plastic, the chains are stretched out in lines, becoming untangled.
This plastic is then wrapped around the goods intended to be shrink wrapped, before heat is applied via a heat gun or heat tunnel. When heat is applied to these straight polymer chains, it provides them with energy and increases molecular motion. This motion results in the polymer chains recoiling and shrinking, returning the molecules back to their tangled state as they press around and cover the item being shrink wrapped. When properly cooled, the polymers will remain in this state, maintaining this tight and durable layer, until enough heat is applied to alter it again.
This tangled state is part of what provides the strength and durability of shrink film, as the intertwining and criss-crossing of the chains makes the polymer harder to break apart.
What Are the Benefits of Shrink Wrap?
Depending on the item you&#;re wrapping you may have a number of options available to you. For example, if you need to secure goods on a pallet you may initially opt for &#;pallet strapping&#;. However, pallet strapping comes with a number of downsides. It&#;s easy to overtighten the strapping which can cause damage to the very items they&#;re supposed to protect (especially fairly &#;soft&#; items such as cardboard boxes which can easily have edges crushed by over-tightened strapping). It&#;s also possible for items to twist free from the pallet if not secured correctly, and strapping doesn&#;t protect goods from the elements.
Shrink wrap on the other hand offers a number of substantial benefits including:
- Increased protection from environmental damage
- Increased stability during transit and storage
- Durable wrapping
- Reduced risk of tampering
- Cost effective as a packaging solution
- Easily adapts to irregular shapes
Increased Protection From Environmental Damage
The tight nature of the shrink wrap ensures increased protection of the encapsulated goods. The item is protected from dirt and debris, as well as having superior moisture protection, and is therefore protected from all the damage these contaminants could potentially cause. Shrink wrap can also include additives such as UV inhibitors, anti-static treatment, and low and non-fusion options for increased protection.
Increased Stability During Transit and Storage
Wrapping goods in shrink wrap gives superior stability to goods when in transit or storage. The tight wrapping ensures the continued rigidity of the pallet or product so there&#;s no risk of it falling over or items falling out, further protecting items from damage.
Durable Wrapping
Shrink film, especially when made from polyolefin or polyethylene, is tough, durable, tear resistant and puncture resistant. Even with obscure-shaped loads, shrink wrap will not loosen once heated and shrunk. Goods will remain tightly protected and upright when in transit or storage.
Cost Effective
Not only is shrink film a relatively low cost, affordable material and form of packaging, it is also a space saver. This tight way of packaging items results in more space available in storage or transit, which could potentially save money when transporting or storing multiple items.
Reduced Risk of Tampering
Due to shrink wrapping being tight and secure, it is more difficult for someone to tamper with the goods once wrapped. Furthermore, any tampering would be instantly noticeable as shrink film doesn&#;t loosen or sag, and isn&#;t easily tearable. It&#;s a great way to ensure the sealed items haven&#;t been tampered with.
Size and Shape Aren&#;t An Issue
No matter the size or shape of the item that is being wrapped, shrink wrapping can do it all. From small, intricate pieces, to large obscure shaped loads, shrink film is a convenient and all encompassing solution for wrapping goods and pallets.
Common Uses for Shrink Wrap
Shrink wrap is perfect for transport and transit as it offers a secure, durable and tamper proof packaging. It&#;s also great for displaying and protecting consumer items as it can be made see through and printed on.
Some products and industries that utilise shrink wrap are:
- Food and drink packaging e.g. cartons and multi-packs (often using collation shrink film)
- Retail packaging e.g. toys, games, books
- Bath bombs
- Boats
- Building and construction
- CD cases
- Healthcare industry
- Electronics industry
- Automobile industry
That&#;s a Wrap
Looking for shrink wrap that meets your needs? Industrial Polythene offers bespoke shrink wrap solutions for any requirement! Get in touch with us to discuss your specific needs.
The three main wraps used in shrink packaging material for protecting and securing products for the retail and shipping environments are polyvinyl chloride (PVC), polyethylene (PE), and polyolefin (POF). Each has different capabilities and characteristics that make them suitable for specific applications.
What are the main differences between these types of shrink wrap? Which is the best choice for your packaging needs? Read on to find out!
What is Shrink Wrap Material?
The material known as shrink wrap is a clear plastic wrap that is used to package millions of products around the world. Shrink wrap is called shrink wrap because it shrinks around the product being packaged when it is exposed to heat.
Each of these three wraps can be co-extruded into multilayer wraps with different additives offering specific barrier properties required for shelf-life or appearance. Shrink wraps can be formed into flattened roll stock, bags, overwrap, banding, and tubing, and add a form of tamper-resistant protection to packaged goods. If you aren't sure that you are using the ideal wrap for your application, here's a breakdown of the three:
PVC Shrink Wrap
Once the most commonly-used shrink packaging material in the world due to its lightweight and inexpensive multi-purpose capabilities, PVC Shrink wrap has since taken a backseat to PE and POF for many reasons. Most specifically due to the dangers in health during creation and incineration, and sustainability.
In its rigid form, PVC is durable and is used in many applications, including construction projects and houseware products. In terms of packaging, PVC is seen in rigid applications including blister and clamshell packaging, & flexible applications including shrink wrap, bagging. Polyvinyl chloride is a combination of three elements, carbon, hydrogen, and chlorine.
It is recommended for use in well-ventilated facilities due to the strong, harmful odors that are released when heated. Due to its chemical composition and these harmful byproducts released during its creation, and decomposition for that matter, PVC has been banned in many countries.
Brands that hold high regard for corporate & social responsibility have been joining these countries in banning PVC in packaging. This is important to consider if you have toyed with the idea of using it in your packaging, and more so if you already are using it. The Walmart Sustainability Playbook specifically targets PVC reduction in packaging materials for the manufacturers of products sold in their stores.
Need Help Choosing The Right Shrink? Check out our complete guide to Shrink Film!
Related links:
BOPP is often the go-to material for film labels | 2019-12-19
Window Film 101: Everything You Need To KnowGoto Herofu to know more.
Fast Facts About PVC Shrink Wrap:
- Once the most commonly used shrink wrapping material in the world
- Temperamental with hot and cold temperature changes, causing brittleness when too cold and wrinkling when too warm
- Higher resistance to propagation of tear, Polyolefin- higher resistance to puncture
POF Shrink Wrap
Polyolefin shrink is an extremely durable and versatile 'premium' shrink wrap. It has taken the place of PVC mentioned above in many applications and is also an FDA-approved food-safe material. Polyolefin materials are available with different characteristics, including cross-linked wrap that provides high-tensile strength and incredible clarity for high-speed packaging applications. The cross-linked wrap also prevents buildup on sealing components of your packaging machinery.
With added strength, the ability to create longer rolls of wrap with thinner gauges available allows for less roll change-over and increased efficiency and productivity. Polyolefin shrink wrap has excellent puncture resistance and seal strength, allowing for irregular-shaped items to have excellent protection throughout their supply chain life-cycle. POF is available in thicknesses as low as 35-gauge (.35 mil) and is more commonly available in 45,60, 75, and 100 (1 mil) gauges.
The versatility and fairly low cost that POF offers for multiple machines and packaging forms make it a go-to form of protective packaging manufacturers of any size. In some instances POF will need perforations added to the wrap; tiny holes added to the wrap before application which allows air to escape during the shrinking process for a smooth package. Pre-perforated shrink wrap is available by many suppliers for this reason.
Fast Facts About POF Shrink Wrap
- Premium quality shrink wrap, AKA high-clarity, decorative shrink wrap.
- Made of 100% recyclable materials
- Excellent clarity and glossy shelf appearance; great for
consumer products where appearance is critical (toys, games, candies, books, foods, most retail items)
- Ability to shrink quickly and completely (
shrinks when heated resulting in a finished good as soon as it comes out of the shrink tunnel)
- Durable, versatile, low cost
- Excellent for bundling multiple items together, like tissue boxes for example.
- Cross-linked POF is great for high-speed applications, providing added strength without compromising clarity and preventing build-up on sealing components
- Polyolefin is more expensive but more durable- not as affected by temperature changes
- FDA approved for food contact
- Excellent tensile-strength and propagation-to-tear
- Pre-perforated POF is available and allows for an even shrink surface, no air pockets
PE Shrink Wrap
Polyethylene is a type of polyolefin, meaning it is a single monomer wrap that is formed with the addition of ethylene during polymerization. PE is used in several forms of flexible protective packaging including shrink wrap and stretch wrap and performs very differently for each.
There are multiple forms that PE can take, but the three most common would be Low-Density Polyethylene (LDPE), Linear Low-Density Polyethylene (LLDPE), & High-Density Polyethylene (HDPE). Each of these is best used in different industrial applications, but for shrink packaging, LDPE would be the most common form.
The benefits of using LDPE over the other forms of shrink packaging would be added strength and durability for heavier, larger items, like multipacks of beverages. These wraps are also printable and can have excellent graphics added while still maintaining the image and the strength required.
Where POF and PVC are limited in gauge thickness to usually around 100 gauge, higher gauges of PE are possible up to gauge! These thicknesses are used in Marine industrial applications, like shrink-wrapping a boat for storage. The disadvantages of PE for shrink are that it doesn't have a high shrink rate, usually around 20%, and it has significantly lower clarity than the other wraps.
The Difference Between Shrink Wrap And Stretch Wrap
Shrink wrap and stretch wrap are often confused as they look very similar, but they perform very differently. When PE is used in a shrink wrap application, it is loosely placed over a single item or multiple items and will shrink around them when heat is applied, creating a tight, tamper-resistant seal of protection. When PE is used in stretch applications, it is formulated differently to be able to stretch around items.
The elastic memory of the wrap, along with its ability to cling to itself, keeps a tight layer of protection around the items. Stretch wrap is generally used for palletizing, AKA unitizing, multiple items on a pallet to keep them from shifting during shipment. Stretch wrap usually stretches about 100-300% where shrink wrap will typically only stretch to around 50-75% before breakage occurs.
Fast Facts About PE Shrink/Stretch Wrap
- LDPE (Low-Density Polyethylene)- low melting point, good stretch & strength - commonly used for foods and meat products and stretch wrapping/palletizing
- LLDPE (Linear Low-Density Polyethylene)
- thinner than LDPE, just as strong, decent clarity - used for bulk foods, frozen foods, prints, grocery, trash bags, palletizing/stretch wrapping
- HDPE (High-Density Polyethylene)
- one of the most common polymers in plastics packaging - USDA/FDA-approved for food contact, lightweight, durable, water-resistant, bad O
2
-resistance- good for certain foods, retail products, clothing, stretch wrap for pallets
- Good for lower-end applications and unitization (24-pack of waters), replacement of master corrugated shippers, larger items
- More expensive, but durable
- Polyethylene shrink wraps are recyclable
- Thicker- offering more stretch-ability
- Shrinks as it cools rather than heats, requiring additional cooling space at the end of the tunnel
- Applications include large heavy items including bundling multipacks of water
- In thicker gauges and larger applications, wrapping boats for storage
Final Thoughts On Shrink Wrap And Stretch Wrap
No matter what the application, knowing your options can help save you money in the long run. It's always best to connect with a supplier that can answer any of your questions that you haven't found clear answers to. They can also help you with custom packaging solutions that match your needs for efficiency, protection, and visual presentation.
If you are using shrink wrap to package your products, we've created a Shrink wrap Cheat Sheet to reduce your packaging costs and increase your packages-per-roll!
Once you have decided on the right wrap for your specific packaging needs, take a look at a minimum of three vendors. Take some time to review product ratings on different brands of wrap. Contact the three chosen vendors and ask each of them for a quote.
Take notes on the quality of the customer service experience from each vendor. Also note the dynamics of the wrap products offered including price, shipping cost, and expected time of delivery. You will want to choose a vendor who treats you like a human rather than a number. If possible, speak to a human being and avoid companies that use a completely automated system with robotic or artificial voice commands and prompts.
Sometimes paying a little extra for better customer service is worth a few extra dollars. In the end, you will want to find a balance between quality customer service and quality products. By utilizing all the information above, you will be armed with the knowledge needed to make the best choice in regards to your wrap and the supplier you buy from.
If you want to learn more, please visit our website Pla Shrink Film.
