Polystyrene(EPS), or Styrofoam, as it is commonly referred, has long been the bad guy of the recycling world. Though ideal for protecting and transporting fragile goods without added weight, its non-biodegradable polymers make it a major environmental pollutant that lingers in landfills, clogs waterways and storm drains, and litters land and sea. Continue reading
Several markets are available for EPS in both closed- and open-loop recycling. Sufficient end markets are available for all the clean EPS collected. Almost half of the EPS packaging recycled—both molded and loose-fill—is remanufactured back into EPS packaging. Continue reading
Processing of EPS Scrap
EPS scrap is generally from construction, packaging and containers. It is costly and difficult to transport due to its volume to weight ratio. Methods of disposing EPS scrap include landfill, burning, extrusion pelletizing, melting, solving, and regrind and mix with concrete. The most convenient and efficient way is to densify the foam scrap and ship to recycler for further processing such as extrusion pelletizing.
Methods to Densify EPS
There are two main options to recycle EPS scrap. One way is to use heat (thermal densification) and the other way is without heating (compression). Compression involves crushing and compacting EPS by machine. The compacted materials are extruded into a solid ‘log’. The log is cut to length to fit onto a pellet. It is usual for the densified EPS to be stored on-site until 5 to 20 metric tones are available, as this makes transport and distribution more cost-effective. The more densely compacted the EPS is, the better, since a higher weight of EPS can be loaded for transport and a higher price per tone may be paid by the recycler. Compression can reduce EPS volume by up to forty times.
Thermal densification involves breaking up and melting EPS inside a controlled-temperature chamber. The temperature is controlled to allow the EPS to melt without burning. Higher compression ratios (up to 95% volume reduction) can be achieved using the melting method that involves heating the expanded polystyrene to a very high temperature to compress the product. The disadvantage of this method is that it involved a hot element that needed to remain powered throughout the day, and this proved to be very energy inefficient and posed safety hazards due to the off-gassing of chemicals. On-and-off operation of the machine can be a big waste of energy and time because of cooling and re-heating of the machine.
Choose the EPS that is Easy to Recycling
Not all materials are well suited for recycling. Post-consumer EPS packaging must be clean and free of tape, film and cardboard. Expanded polystyrene made with a fire retardant additive, typically used in the manufacture of EPS building insulation, requires special reprocessing conditions.
How to Make Use of Recycled Polystyrene?
Since EPS foam is made of thermoplastic called Polystyrene, and it can be recycled and make polystyrene material again.
The recycled EPS pellets can be than being used for many applications. Here are just a few examples:Re-use in injection molding applications – examples include plastic stationery products, video and CD cases, coat hangers, plant pots, etcRe-use in extrusion applications – one example, hardwood replacement, can be used to make products such as garden furniture, window and picture frames.