Q: What is Styrofoam?

A: Styrofoam (Expandable Polystyrene or EPS) is made from PS resin granules impregnated with a blowing agent (typically pentane). Expanding beads fuse together to form the finished product, which is white, and 95 to 98 percent air and another 2 to 5% is polystyrene which is pure hydrocarbon. Small beads are used for cups and containers, medium beads for shape-molded packaging, and large beads for the expanded loose-fill packaging (peanuts). It insulates, is lightweight, and resists moisture.

Styrofoam packaging Styrofoam insulation Styrofoam cups

Q: How to produce Styrofoam?

A: Styrofoam (Expanded Polystyrene or EPS) is PS foam that use pentane gas as the blowing agent. During the material production process call “Polymerization” the polystyrene resin granules impregnated with the blowing agent. Styrofoam production process begins in the pre-expansion process where the Styrofoam bead will expand by the heat of steam usually 50 times in volume. Next step is molding process where expanded foam bead will be heated again with steam then they expand further until they fuse together, forming as foam products.

Q: How to manage the Styrofoam foam waste?
foam stucture

A: Waste Styrofoam is generally from construction, packaging and container. It is expensive and difficult to transport due to its volume to weight ratio.
The main methods to treatment used Styrofoam are as follows.

Styrofoam waste

  • Landfill: unable to biodegrade;
  • Burning: generating heat;
  • Compacting and pelletizing: using Styrofoam recycling and pelletizing machines turning waste Styrofoam into PS pellets and manufacturing various products such as coat hanger, flowerpot, video cassettes, etc.
  • Melting and pelletizing;
  • Reground and mix with concrete to produce new building products such as prefabricated concrete blocks to reduce the weight and increase insulation properties;
  • Crush into small particle and mix with soil to improve ventilation in the soil.

Q: How to recycle used Styrofoam?

A: Since Styrofoam foam is made of Polystyrene, which is thermoplastic, so that it will become again a polystyrene plastic when recycled. There are two main options for recycling Styrofoam waste: incineration – yielding energy-recovery, and recycling into other forms such as garden furniture and building insulation. Both require the Styrofoam to be compacted first.
How to Recycle Styrofoam

Q: How to densify Styrofoam?

Styrofoam melting desification

A: Densification can be carried out with heat (thermal densification), or without heat (cold compaction).
Cold compaction involves crushing and compacting Styrofoam 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 compacted Styrofoam 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 Styrofoam is, the better, since a higher weight of Styrofoam can be loaded for transport and a higher price per tone may be paid by the recycler. Cold compaction can reduce Styrofoam volume down to one-fortieth of the original.

Thermal densification involves breaking up and melting Styrofoam inside a controlled-temperature chamber. The temperature is controlled to allow the Styrofoam to melt without burning. This collapses the expanded foam cells, enabling it then to be recycled into other products. Higher compaction ratios (up to 95% volume reduction) can be achieved using the melting method that involves heating the expanded polystrene to a very high temperature to compress the product. This type of reycling 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.

Q: What is the price to compact Styrofoam?

A: China is the biggest market for densified Styrofoam in the world. The CIF Hong Kong price for compacted Styrofoam will ranges from around US$200 to US$500 per ton but is very much dependent on location, cleanliness, level of compaction and current market situation. Contaminants such as seafood waste, oils, excess moisture, ice, malodors and the presence of paper/plastic labels can generate problems for recycling and reduce the prices to be paid.

Q: Do I need an Styrofoam densifier?

A: Businesses with regular quantities of Styrofoam waste should consider the use of densifiers to initially reduce the volume of Styrofoam that is thrown away, which in turn could save money by reducing the number of times the bin requires emptying.
For a company with around 20 tons of Styrofoam per year, the payback period for a compacting machine costing around US$5,000 can be as short as one years, if the compacted Styrofoam is sold to a recycling company for about US$200 per ton and the costs of disposal to landfill are saved.
For companies with a large volume of Styrofoam waste, it may be cost-effective to establish an in-house Styrofoam densifying facility, to supply Styrofoam recyclers direct.

Q: Can all kind of waste Styrofoam be recycled?

Styrofoam transportation

A: No. If you want to recycle any Styrofoam, please make sure it is clean, with no stickers, grease, dirt, tape, labels, etc. If it’s too difficult to remove a label or contaminant, simply break off the offending piece and recycle the rest. The recycler will chop up the Styrofoam anyway and turn it into new packing material.

Q: What is the market for recycled polystyrene?

A: Almost half of the Styrofoam recycled is remanufactured into Styrofoam packaging. Other applications for Styrofoam recycling include building applications such as siding and deck board, ceiling texture, molding, electronic products, auto products, agricultural products, office supplies, egg cartons, and beanbag filler. Markets for non-foam PS include coat hangers, picture frames, waste baskets, videocassettes, flowerpots, and nursery trays.

Styrofoam blocks coat hangers CD cases


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