Shrink Wrap vs Stretch Wrap
Shrink Wrap vs Stretch Wrap
The Difference Between Shrink Wrap and Stretch Wrap
Shrink wrap and stretch wrap are popular types of plastic film used in the packaging of a range of goods and products. However, despite their similarities, stretch wrap and shrink wrap are used for different packaging projects and provide unique qualities. So, what are shrink film and stretch film – and what are their key differences?
What is Shrink Wrap?
Shrink wrap - also known as heat shrink wrap - is a plastic film used in the primary packaging of a range of products. This means it is wrapped directly around products.
It is a popular packaging solution due to its unique ability to form perfectly around its contents, whatever their shape or structure. This makes it a compact, secure, and hygienic packaging method used for smaller, individual items like food, toys, and gadgets. However, it can also be used to wrap large items.
Shrink wrap is a durable plastic film that becomes even stronger as it reduces and forms around its products.
What is Stretch Wrap?
Stretch wrap is an alternative plastic film that is used as a secondary packaging solution - meaning it is applied to multiple products as a secure way of bundling them together in transit or storage.
Rolls of stretch film are typically applied to large collections of items, like pallets, providing robust protection against damage and the elements. It can be wrapped around its contents manually or using a stretch wrapping machine.
What Are They Made From?
Shrink wrap and stretch wrap are both types of plastic film with unique qualities that lend themselves to the benefits of each product.
Shrink wrap is commonly made from polyolefin plastics - a versatile material that lends itself to the heat shrinking process. As the plastic cools after being heated, it becomes tougher and more durable than its original form to protect its contents. Shrink wrap is also often made from PVC, polyethylene, and polypropylene plastics.
Stretch wrap is typically made from polyethylene plastics - a flexible yet strong material that is tear- and puncture-resistant, as well as waterproof, making it ideal for use as secondary packaging, protecting pallets against damage and the elements.
How Do They Work?
Heat shrink wrap is unique in the way it is applied to products.
Firstly, plastic shrink film is wrapped around a product before any open ends are sealed to create an air-tight barrier.
Heat is then applied to the film - either via a heat gun or heat tunnel - which shrinks in size and forms perfectly and snugly around the exact shape of its contents.
This process is possible because of the plastic polymers present in the film. In its pre-heated state, the film consists of straight polymers, which break down and move freely when heated - allowing the film to reduce in size. When the film then cools and sets into its new shape, its tensile strength increases, providing a tough and durable protective barrier.
The stretch wrap process is a simpler one.
Stretch wrap is simply wound around its contents in layers, locking them in place and providing a protective barrier against damage and the elements when the pallet is in transit or storage.
This process can either be done manually using hand stretch wrap - typically for lower-volume projects like single pallets - or using a stretch wrap machine, which speeds up the process by rotating the pallet to provide more efficient coverage. This is usually used for high-volume wrapping projects.
Which Products Do They Protect?
Another significant difference between shrink and stretch wrap is in the products they are applied to.
Shrink wrap is a primary packaging solution that is applied directly to products, providing a layer of protection between the item and the consumer.
It is typically used to wrap consumer items, such as food, toys, gadgets, and leisure items. However, shrink wrap can also be used to wrap large items.
Some items that are commonly shrink-wrapped include:
- Frozen food like pizzas
- Leisure items like books, DVDs, magazines, and board games
- Large machinery and boats
Stretch wrap is a secondary packaging solution that bundles and secures multiple - often individually wrapped - items.
The film's flexibility, tough puncture-proof finish, and ability to wrap loose items together tightly make it ideal for use with fragile items and those prone to becoming loose when secured using other packaging methods.
Stretch film is typically used to wrap pallets, stacked boxes, bundled wood, bricks, rolls of carpet, large glass panels, and more.
The Pros and Cons of Shrink Wrap
Each wrapping solution offers a unique range of benefits. Here we'll look at the advantages and disadvantages of shrink and stretch wrap.
Advantages of Shrink Wrap
Shrink wrap provides various benefits, including being an ideal compact wrapping option for products that need to be stacked or stored in containers. No space is wasted as the plastic film shrinks to fit perfectly around its contents.
During the heat shrinking process, the film's tensile strength also increases. This makes shrink wrap a durable protective wrapping, preventing tearing and keeping products safe and hygienic.
Plus, shrink film maintains its transparency even as it reduces in size, making it an ideal consumer packaging option, as buyers can view items through the wrapping without directly handling them.
Disadvantages of Shrink Wrap
The main disadvantage of shrink wrapping is the demand for specialist equipment. Due to the heat shrinking process, the wrapping method requires a sealer to close open ends and either a heat gun or a heat tunnel for shrinking.
Shrink wrap film is also typically more expensive than alternatives and some plastic films release an odor when heated.
The Pros and Cons of Stretch Wrap
Advantages of Stretch Wrap
Stretch film is typically made from LLDPE plastic, a cost-effective alternative to other plastics, such as polyolefin.
It is also a tough and durable plastic, making it ideal for use as a secondary packaging solution as it is torn- and puncture-resistant. Stretch wrap is also water-resistant to protect its contents against the elements.
Plus, hand stretch wrap can be applied to products without special equipment. Users can simply wind the film around pallets in layers, creating a protective barrier against damage.
Disadvantages of Stretch Wrap
Stretch wrapping can be a costly exercise when working through high-volume packaging projects. This is because it requires specialist equipment, like pallet wrapping machines or pallet turntables, to make the project more efficient.
What Equipment Do I Need?
Both shrink wrap and stretch wrap require special equipment for high-volume packaging projects. However, depending on your needs, various machinery and equipment are available to facilitate both packaging methods.
Because of the heat shrinking process that activates the shrink film, shrink wrap machines will be needed. The type of equipment is determined by production levels and product size. Essential machine components include:
- Sealer - to close open ends and create an enclosed seal. This is often an I-bar or L-bar sealer.
- Heat gun - a hand-held device used to apply heat to shrink film. This is often used for lower production.
- Heat tunnel - a larger machine that applies heat to shrink film when wrapping products for more production.
While hand stretch film can be applied to pallets manually, users will still need specialist machinery when working through high-volume packaging projects. This includes:
- Pallet turntables - designed to maneuver heavy pallets to speed up the stretch-wrapping process.
- Stretch wrap machines - machines designed to apply stretch film while turning pallets for efficient wrapping.
|Shrink Wrap vs Stretch Wrap|
|Shrink Wrap vs Stretch Wrap||Shrink Wrap vs Stretch Wrap|
|Made From:||Commonly polyolefin plastics but also PVC, polyethylene, and polypropylene plastics.||Most commonly PVC plastics|
|How They Work:||Film is wrapped around items, end(s) are sealed, and heat is applied to shrink the wrapping around the shape of the product.||Film is wrapped in layers around multiple products – either manually or using a machine – to keep them in place.|
|What They Protect:||Smaller individual items like food, toys, and gadgets. Occasionally larger items like machinery.||Large batches of products such as pallets.|
Do I Need Stretch Wrap or Shrink Wrap?
The most effective packaging solution depends on your needs.
Shrink wrap provides a direct protective barrier to individual items like food and accessories. Using shrink wrap with a shrink-wrapping machine is ideal for fulfilling high-volume product packaging orders to keep them secure and hygienic until they reach the customer.
Stretch wrap is the perfect solution for bundling large batches of items, such as palletized loads. It is a strong, durable, and flexible film that wraps around various shapes and sizes and keeps stacked products safe until they reach the retailer, reseller, or other recipients.
Explore our range of shrink and stretch wrap solutions or ask our expert team how US Packaging & Wrapping can support all your high-volume packaging projects today.