Updated: Sep 11, 2020
Although the common misconception that EPS (Expanded Polystyrene foam) cannot be recycled, it is easily recycled. The two most common methods are either grinding or compressing the foam. A foam shredder is best used when the foam will be further used as filler for toys and furniture or as a building material. Compactor will be best used to press the foam into logs, making it easier for transportation to a facility where it can be melted and molded into new material. The decision of which machine and methods to use lies on the foam applications.
Expanded Polystyrene foam, also known as EPS is a polymer made from the monomer styrene, normally solid at room temperature. EPS is a mixture of about 98% air and only 2% polystyrene. It is a highly popular plastic packaging material found in packaging of food, electronics, furniture and more. The questions to be asked are if EPS can be recycled, and if so, how? Is shredding it preferred over compacting it or vice versa?
There is a misconception that EPS is non-recyclable. However, EPS is easily recycled due to its light weight and the fact that it is partially made of air. Being a plastic-like material, EPS can be heated, melted and molded into many plastic items by being forced into palletizing extruders machines. But, the two most common recycling methods for EPS is either shredding it or compacting it. In any case, it is not economical not efficient to just pile up all the scrap foam.
The EPS can be put into the foam shredder. The machine will grind the foam pieces and will turn them into small beads about 5-10mm in diameter. Shredding the foam will not only make the recycling process easy, but will also greatly reduce the transport cost, and become a recyclable commodity of high value. Another great benefit for shredding EPS is that the foam beads can be reused as filler to cushions, bean bags, toys, stuffed animals and beanie babies. It can also be extruded into plastic pellets or used as the building material in the filling agent or as adhesive.
Another method of recycling the EPS foam is to compact it. The scrap foam pieces are placed into a compactor that will compress and press it, squeezing out the excess air. Some compactors can achieve volume reduction of up to 50 to 1 its original volume, which is reduction of about 98% its original volume. The end result is foam logs that can be stacked on top of each other. After compacting the foam it can be re-melt to make pellets for the application of injection molded parts. Compaction of foam is especially beneficial in cases where there is a need to transport it to a recycling and reuse facility. The transportation of the logs is cost effective and easy due to its light weight. The logs can be cut to the desired length, so that they can be placed easily into a pellet. Storing the logs on site is also easy and does not take up a lot of space. Using a compactor can reduce the volume down to one-fortieth of the original size of the foam.
No matter which machine or method is used to recycle the foam, there is no doubt that we do need to recycle. There is an increase recently in EPS production which necessitates recycling it both for conserving the environment and for economical reasons. The answer to the question of which machine or method to use – compactor or shredder lies in the purpose of the recycled foam. If the company or organization will use the recycled foam as fillers, or if they will use it for further mixing the foam with concrete to create lightweight building materials then shredder is the better choice. If they intend to further melt and remold the foam to different plastic products, then turning the scrap foam into logs using a compactor is the better choice.