Styrofoam, also known as Expanded Polystyrene, EPS or recycle #6, is commonly used as trays, plates and cups in the food industry and as a great packaging material due to its light weight, low cost production rates, its sustainability and durability. It is made from styrene, a petroleum by-product and is a mixture of about 98% air and only 2% polystyrene. But Styrofoam hardly breaks down over time by itself, making it a bit of a challenge for landfills and companies when it comes to recycling the material. If buried in the ground, it takes up a lot of space, if burned it creates unpleasant ashes, so what is the best method to recycle Styrofoam or to dispose of it?
There is a misconception that EPS is non-recyclable. However, the material is actually easily recycled due to its light weight and being mostly 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. The question to be asked is how should we recycle it? Is shredding it preferable, or compacting it, or maybe melting it would be best?
One thing is for sure – It is not economical not efficient to just pile up all that excess scrap foam.
The EPS can be put into a foam shredder that 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 EPS is to use hydraulic densifier, also known as compactor. 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 95% its original size. The end result is densified foam logs that can be stacked on top of each other. After compacting the foam it can be re-melted to make pellets for the application of injection molded parts. Compacting EPS 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.
But EPS can also be melted by a method of feeding it into a thermal densifier. The machine uses heat to melt the foam, then pressing it through a narrow outlet. The end product is a solidified long “rope like” melted material. The material can then be easily transported to a required factory to be remolded again with heat and pressure into new EPS products. This method of EPS recycling reduces the original foam size by about 98% of its original size.
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, shredder or densifier 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 a 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. plastic shredder machine