Processes

Depolymerization

Chemical recycling process in the context of polymer recycling

Virgin grade raw materials are essential to produce polymers with clearly defined properties. By depolymerizing end-of-use plastics virgin grade monomers can be obtained. For this purpose, polymers with polar covalent bonds are specifically suited.

Single-StepDepolymerization

Suitable polymers can be converted into monomers by single-step (bulk-)depolymerization. In this process, the polymer is disintegrated with catalysts in its own melt without adding liquid reaction agents. Operating under vacuum, the monomer is simultaneously evacuated, to be condensed outside of the reactor afterwards. The recovery rate can achieve >90%.

Your material

  • PA

  • PET
  • PMMA
  • PS
  • PU

  • Silicone

Our Solution

  • Process intensification: Efficient continuous depolymerization of polymers without addition of liquid reaction agent

  • Dosing and heating of the polymer; stoichiometric mixing of the catalysts

  • Efficient reaction and evaporation due to enforced interfacial renewal.

  • Fouling-free reactor design and trouble-free continuous discharge of various residuals

  • High evaporation rates without product entrainment resulting in simple and stable process control

  • Extensive testing facilities in our test centers in Switzerland and Korea, for targeted process development

  • Industrialization experience for scales up to 10 t/h polymer

Two-StepDepolymerization

Solvent-based processes allow it to recycle plastics back to monomer by using an additional liquid reaction agent. The Kneader makes it possible to reduce the amount of liquid agent to a minimum.

In a first step polymers from Polycondensation are depolymerized by adding an excess of condensate and by mixing in catalysts. In a second step, the monomer is separated from the reaction mixture.

Your material

  • PET
  • PU
  • PA

  • Silicone

  • Cross-linked polymers

Our Solution

  • Efficient continuous depolymerization of polymers while minimizing amount of liquid co-reactants
  • Dosing and heating of the polymer and stoichiometric mixing of the catalysts
  • Optimal reaction conditions and accessibility of liquid co-reactant to polymer due to high interfacial renewal
  • Fouling-free kneader design and continuous discharge of reaction mixture

  • Extensive testing facilities in our test centers in Switzerland and Korea, for targeted process development

  • Industrialization experience for scales up to 10 t/h polymer

Detailed process descriptions of the process steps shown above

Number 1: interconnected gas headspace, large vapour cross sections

Number 2: large heated surface, vacuum design, fouling-free, self cleaned, robust all-phase design

Number 3: viscous screw and solid weir discharge

Number 1: viscous screw and liquid weir discharge

Nummer 2: large heated surface, over pressure design, forced viscous mixing

Number 1: interconnected gas headspace, large vapour cross sections

Number 2: glarge heated surface, robust all-phase design, vacuum design, fouling-free

More about us

Polymer Recycling

The plastics industry is undergoing a major transformation: what used to be waste is now becoming a valuable resource for new plastics.

Twin-Shaft Kneader Reactor

We present: the twin-shaft kneading reactor—a high-performance solution for demanding mixing, reaction, and drying processes.

Applications

LIST kneader reactors process materials with high efficiency where other machines fail due to rheological challenges. From high-performance polymers and synthetic rubbers to cellulose fibers from recycled textiles, as well as specialty chemicals and active pharmaceutical ingredients.