Technology

Polystyrene Recycling

Polystyvert has developed a unique dissolution technology for recycling polystyrene.

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Polystyrene is placed in contact with an essential oil (solvent) that dissolves it in seconds. This essential oil is very safe, and can easily be reused to recycle more material.

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Le mixture of dissolved polystyrene and essential oil is then purified to attain a high level of purity for the next step: the separation of polystyrene from the essential oil.

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This separation process lies at the heart of our innovative technology, which is currently patent-pending. It overcomes the main challenge of recycling polystyrene. Even a trace amount of essential oil is enough to impact the quality of recycled polystyrene.

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The final recycled product is pelletized, while the essential oil is also recycled for the next dissolution cycle.

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Polystyvert’s recycled polystyrene retains the same properties as virgin polystyrene, since our solvent does not modify the polymer in any way. Moreover, our processes are carried out at a low temperature, which keeps the molecular chain of polystyrene intact.
This enables Polystyvert to attain a high-quality recycled product. Due to its high quality, a strong proportion of this product can be incorporated into various finished products such as insulation panels, food trays, etc. It can also be directly extruded, like virgin polystyrene, but within a more ecological framework!

Reducing Transportation Costs

The dissolution of polystyrene can be done in a recycling plant. It can also be conducted directly on-site where polystyrene residues are collected, such as a food distributor, a pharmaceutical warehouse, or a furniture store. Polystyvert’s dissolution equipment can be placed on-site, and adjusted according to the client’s needs.

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Our concentrator model that contains cartridges of solvent is effective for smaller volumes of polystyrene residue or quantities that need to be picked-up frequently. The cartridge with solvent, located in the bottom half of the concentrator, dissolves polystyrene as it is inserted into the concentrator. When the solvent is saturated, we send a truck to pick-up the cartridge and replace it with a new cartridge of fresh solvent to carry on the dissolution process. This concentrator is ideal for large stores, for example.
Polystyvert has also developed large-scale dissolution equipment located in its plant. This equipment can dissolve important volumes of polystyrene at a time, when fed continuously with a conveyor at an accelerated speed. This equipment is ideal for rigid polystyrene residues such as bundles of polystyrene packaging and waste electrical and electronic equipment (WEEE).
Dissolution reduces the volume of expanded polystyrene by a factor of 10. Thus, in its dissolved state, 10 times more polystyrene can be put into the same truck and transportation costs are dramatically reduced, compared to transporting polystyrene in its expanded form. GHG emissions are similarly significantly reduced.

Decontamination and Thorough Purification

Polystyrene with contamination represents the main obstacle to its recycling.
Polystyvert’s dissolution technology allows the largest contaminants to be removed initially, due to a screening step. During this step, the mixture of dissolved polystyrene and essential oil is poured through a simple mesh that holds back contaminants like paper, tape, cardboard, other plastics, metals, etc.

The purification step is followed by the separation of dissolved polystyrene from the essential oil. During this step, HBCD, the flame retardant that is now banned and is still found in some types of polystyrene, can be removed. Polystyvert has attained a high removal rate for HBCD, which is below the detection limit.
Polystyvert has also perfected a solution to eliminate fine particles and contaminants that remain in the solution, such as ink, pigments, and different types of additives. This low-temperature chemical process, for which a patent application has been filed, avoids using filters that are costly and have to be replaced frequently.

Re-Polymerization

Polystyvert’s recycled polystyrene has a high degree of purity, thus far unequalled. Therefore, our recycled polystyrene can be easily introduced into a polymerization reactor.

In the reactor, an expansion gas can be added to re-make expanded polystyrene with the same properties as expanded polystyrene made from virgin polystyrene, but with a high proportion of recycles material ; indeed, polystyrene is regenerated.

It is also possible to add butadiene to high-impact polystyrene (HIPS) in the polymerization reactor. Likewise, a product with the characteristics of a virgin polymer, but with a high recycling content, is obtained. The term ‘up-cycling’’ can also be used to describe this technological breakthrough.