How is LDPE Film Recycled?
Polyethylene is usually manufactured either of two ways, Low Density or High Density. Other than the scientific differences in their make up, the most noticeable difference is their strength and weight, which you may have already worked out from their names.
In this piece, we will look specifically at Low Density Polyethylene Film, something you may commonly find at home in the form of cling film. Whilst cling film wasn’t always made from LDPE, decades of research found that previous plastics used for covering food were leaking chemicals and deemed unsafe to use.
You will often find LDPE film used for agricultural purposes, especially for keeping thinking like strawberries, mushrooms and tomatoes fresh. LDPE is thinner than HDPE, but sometimes they are used for similar purposes, like in warehouses, for wrapping pallets. Because of how robust the film is, and also how transparent, it has become ideal for many purposes. Let's begin... First, the film is collected, often from warehouses or farms, and then it is taken to a recycling facility.
One of the great challenges for recycling LDPE film is that because many of its uses are agricultural, it is often dirty and contaminated, and must go through a proper cleaning and sorting process before it can be recycled. This can be time, energy and financially inefficient, but thankfully technologies are improving to make it better all the time. Once clean, the other challenge comes for the recycling machines. A general recycling machine would get LDPE film stuck in its teeth, causing damage to the machine and creating problems. Special LDPE recycling machines are able to chew up the plastic into small pieces and then form them into pellets. The pellets are important... LDPE recycling
machines create small pellets that can be turned into a variety of things, and are often mixed with a bit of virgin LDPE to improve their strength and reliability. Black bin bags, black agricultural film (like the type you may see spread over a field) or irrigation pipe are all likely to be made from recycled LDPE. Commonly recycled LDPE will be black, because with recycling plastics, it’s easy to turn a clear plastic black, but impossible to turn a black plastic clear!
Processing LDPE is among the easiest of the plastics, with the potential for injection moulding, rotational moulding, film blowing and blow moulding. It can be made anti slip, anti-static, antibacterial and flame retardant!
With all this ease and potential, it makes sense for LDPE recycling to be a massive and growing industry in the UK, but there is always room for improvement. Right now, the greatest task remains trying to make the plastic clean and decontaminated in an efficient way.