When it comes to the different types of films, there’s some confusion out there. And like most of our blog posts, we seek to thwart the confusion.
A film is any kind of very thin membrane or barrier film made of plastic. Film can be flexible or rigid. If it’s rigid, it’s called a sheet of film. If it’s flexible, it’s called flexible film. Flexible film is made from resins that once formed is…flexible! This type of film can be used to make various types of bags, pouches, single-serving condiment packets, frozen food film, box liners, and more. Flexible film can be easily bent or crumpled without failure to its integrity or structure.
Flexible film can be extruded from a single polymer to form a single layer. Mono-layer Co-extruded film has had multiple polymers mixed to form a single layer by extrusion. Single or multi polymer, single layers of film can be fused using adhesives or heat to form multilayer flexible films.
Metalized films are polymer films coated with a thin layer of metal, usually aluminium. They offer the glossy metallic appearance of an aluminium foil at a reduced weight and cost. Metallized films are widely used for decorative purposes and food packaging, and also for specialty applications including insulation and electronics.
In general, film has many uses, including lining boxes, mixing with metal to create a shine, composite films with multiple layers, and lamination of paper products.
Shrink film and stretch film are both flexible film with different types of additives designed to shrink or stretch it.
This can be stretched over or around a stack of items to make them stay together and keep the tower upright. It’s most commonly used for stacks of boxes or cases on a pallet for transportation or storage. Stretch film can be stretched up to 500% before breaking, but in practice, the range is more like 100-300%. It’s commonly made from linear low-density polyethylene (LLDPE), other types of polyethylene, or PVC. We’ll cover these more soon.
This type of film can be used to encase a group of items or a package. With the application of heat, it shrinks to form around a single item, or a group of items. Shrink film is commonly made to shrink overwhelmingly in a single dimension so that the film shrinks more on the length than on the width, or vice versa. When shrunk, the bundle of items may be completely covered and sealed, which is called full enclosure wrapping, or the ends on either side of a package are open and called bull’s eye bundling. These holes in the film can be used for gripping. This type of film is typically made from PVC, low-density polyethylene, or polypropylene. A more sustainable option is PLA.
We hope this post has offered you some valuable insight into shrink vs stretch film and the plastics that make them. If you’re considering a switch or upgrade to your manufacturing process, please give our office a call. Our experts can advise not just on films, but on pretty much any packaging technology. We specialise in integrating packaging technologies so that your production process runs smoothly, up to quality requirements, and under budget. We hope to hear from you, and we hope you continue to enjoy our blog!