If you are new to packaging, you may be confused about the difference stretch film and shrink film. Afterall, if they are both made of plastic – how different can they be?
Although shrink and stretch are sometimes mistakenly used interchangeably, there are significant differences between the two packaging methods.
Stretch wrap is a thin, stretchable plastic film (typically made from polyethylene) that is used to lock and secure cased goods onto a pallet. As the stretch film is wrapped around the pallet, tension is applied, enabling the film to extend its length by up to 300%. This tension then creates a constrictive force around the load, allowing it to be held in place.
1. Hand Stretch Film
Hand stretch film is specifically designed to be applied manually and is therefore typically utilized in low-volume packaging operations.
2. Machine Stretch Film
Machine stretch film is film that is specifically designed to be applied with a stretch wrap machine and is typically utilized in high-volume packaging operations. Some common types of machine stretch film include:
Blown Stretch Film – is manufactured using a blown extrusion process. This process involves blowing heated resins into a bubble. The bubble is then transformed into sheets that are rolled and applied to a core tube.
Cast Stretch Film – is manufactured using the cast extrusion process. This process involves feeding heated resins through a line of cooled rollers which then solidifies the film.
Pre-Stretched Film – is film that has been pre-stretched during the manufacturing process.
Shrink wrap, on the other hand, is a plastic film that is typically used to package the product itself (such as toys, DVDs, fresh produce, frozen foods, etc.), rather than a case of goods. When heat is applied, the plastic shrinks to fit whatever it is packaging, creating a tight, protective wrap.
There are two common types of shrink wrap:
Polyolefin – offers virtually no odors, great clarity & appearance, durability, & versatility. Ideal for freezer applications and is printable.
Polyethylene – offers lower clarity that other films but its thicker characteristics make it durable. Polyethylene tightens around the package when introduced to cool air at the last stage of the packaging process. Offers great protection for shipped products.
Rotary arm stretch wrappers use a mechanical arm that rotates around the load. They are particularly useful in wrapping loads that are either very heavy or light which can create instability. Rotary arm stretch wrappers can come in automatic and semi-automatic formats and are well-suited for operations wrapping 40 loads/hour.
Orbital horizontal ring stretch wrappers use a vertical rotating ring to wrap the cased goods inside it and excel at wrapping long and wide loads such as lumber, doors, windows, piping, textiles & more.
Rotary arm stretch wrappers use a mechanical arm that rotates around the load. They are particularly useful in wrapping loads that are either very heavy or light which can create instability. Rotary arm stretch wrappers can come in automatic and semi-automatic formats and are well-suited for operations wrapping 40 loads/hour.
Automatic side seal shrink wrappers use a mechanical arm to trim and seal shrink film around products. Featuring high speeds and continuous motion, these machines are a great solution for higher packaging operations that seal up to 100 packs/minute.
Known as the ‘heart’ of shrink wrap systems, shrink tunnels create a temperature-controlled chamber in order to tighten shrink film that has already been applied by another shrink wrap machine. Shrink tunnels are available in both single and dual chamber formats, whereby dual chambers allow for faster packaging speeds.
Shrink bundling machines use a horizontal sealing arm to wrap bundles of products (both with or without trays) like water bottles or cans.
1 – Reduced Shipping Damages – Goods that are being shipped can be subject to an array of events that have the potential of damaging them. Stretch film aims to reduce these hazards due to its ability to hold loads tightly together onto the pallet so that they do not shift as much while in transport.
2 – Protection Against the Elements – Stretch film also works to protect goods from environmental damage such as dirt, dust, and moisture.
3 – Sustainability – Many types of stretch film are recyclable.
4 – Cost-Effective – compared to other packaging methods like strapping, stretch film can be a cost-effective alternative.
5 – Versatile – the stretchy characteristics of stretch wrap enable oddly-shaped or hard-to-stack loads to be wrapped.
1 – Product Protection – Shrink wrap keeps contaminants like dust and moisture at bay.
2 – Tamper Evident – Any tampering with a product will be immediately noticeable.
3 – Increased Branding Space – Many shrink films can be custom printed to include a business’s branding.
4 – Extends Shelf Life – Shrink film (when utilizing modified atmosphere packaging) can extend the shelf life of fresh produce by preserving and prevent spoilage.
A stretchable film typically made of polyethylene.
| Used to wrap individual products like DVDs, cucumbers, frozen foods, etc. |
Types:
Types:
Equipment:
Equipment:
Benefits:
1 – Reduced shipping damages
2 – Protection against the elements
3 – Sustainability
4 – Cost-Effective
5 – Versatile
Benefits:
1 – Product protection
2 – Tamper-evident
3 – Increased branding space
4 – Extends shelf life
Whether you need shrink or stretch film really depends on the type of products you are packaging. If you are unsure of which type of film you need, it is best to consider bringing on a packaging expert to look at your packaging operation to help determine the right film for your application.
Contact Crawford Packaging today to access our fleet of knowledgeable packaging specialists.
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