Foam#6 is now extensively used across different industries for applications such as packaging and building insulation because of its thermal insulation, noise absorbent, durability, and lightness properties. The United Nations Environment Programme (UNEP) research shows that the consumption of foam plastic is more than 350 million tons a year, with producing more than 100 million tons of white waste. However, as the degradation time of foam plastic is relatively long (about 500 years), the method of foam recycling is still limited to the use of foam recycling equipment like foam densifier.
At present, four commonly used densifiers are hydraulic, thermal, screw drive, and a hybrid, all of the four types could reduce various lightweight foam#6 materials to dense blocks, logs, and ingots, while based on different working principles. Let's take a look at how four different foam densifiers work while recycling foam#6.
The thermal densifier uses heat to melt foam#6 into a taffy-like state. There is a rotating cutter and a hot melt screw inside the machine, squeezing the air inside the foam#6 waste by crushing and screw heating. Finally melted foam#6 waste will be as hard as a solid brick. Additional labor is required to mold the foam#6 into a shape that can be stacked on a pallet. While the machine does a great job compacting foam, it is known to produce unpleasant odors and requires more electricity to operate. Meanwhile, melting compacting systems need plenty of ventilation because these systems melt and even burn the material.
Screw Drive Densifier
The screw drive densifier uses augers to push foam#6 through a chamber at a specific speed and pressure to densify the foam into a solid log or block. The material is compacted by pressure, not heat, so screw compactor systems could start processing foam#6 immediately. And it performs best when the feedstock is limited to one density of foam at a time.
The hydraulic densifier uses hydraulic pressure to compact foam#6 and eliminates its memory to extrude the foam into a dense log. It can effectively process various densities of foam at the same time without melting in the machine, so it wouldn’t produce smoke or odors. But it could be prone to leakage and higher maintenance because of hydraulic valve failure.
Hybrid Foam#6 Densifier
The hybrid foam#6 densifier combines the advantages of the hydraulic densifier system with the screw drive densifier system. It uses augers and hydraulics to compact foam without melting. The advantages of the Hybrid foam#6 densifier are neat output, small floor area, high output density and controllability.